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1
Yu, Yixin. "Negative bias temperature instability and charge trapping effects on analog and digital circuit reliability." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4056.
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Nanoscale p-channel transistors under negative gate bias at an elevated temperature show threshold voltage degradation after a short period of stress time. In addition, nanoscale (45 nm) n-channel transistors using high-k (HfO2) dielectrics to reduce gate leakage power for advanced microprocessors exhibit fast transient charge trapping effect leading to threshold voltage instability and mobility reduction. A simulation methodology to quantify the circuit level degradation subjected to negative bias temperature instability (NBTI) and fast transient charge trapping effect has been developed in this thesis work. Different current mirror and two-stage operation amplifier structures are studied to evaluate the impact of NBTI on CMOS analog circuit performances for nanoscale applications. Fundamental digital circuit such as an eleven-stage ring oscillator has also been evaluated to examine the fast transient charge transient effect of HfO2 high-k transistors on the propagation delay of ring oscillator performance. The preliminary results show that the negative bias temperature instability reduces the bandwidth of CMOS operating amplifiers, but increases the amplifier's voltage gain at mid-frequency range. The transient charge trapping effect increases the propagation delay of ring oscillator. The evaluation methodology developed in this thesis could be extended to study other CMOS device and circuit reliability issues subjected to electrical and temperature stresses.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
2
Koton, Jaroslav. "Syntéza a analýza obvodů s moderními aktivními prvky." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233476.
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The dissertation thesis deals with the synthesis and design of active frequency filters using current (CC) and voltage (VC) conveyors, or current active elements CMI (Current Mirror and Inverter), MCMI (Multi-output CMI) and PCA (Programmable Current Amplifier). As introduction, these active elements are described as suitable for the design of the circuits working in the voltage-, current,- ,and mixed-mode, or in pure current-mode speaking about the current active elements. The new frequency filter structures presented in this thesis using the above mentioned active elements were designed by the generalized autonomous circuit method, transformation cells and signal flow-graph theory. The generalized autonomous circuit method is based on full admittance network to which generalized active elements are connected. The described admittance networks can be used for other active elements. The next method is based on the transformation cells that subsequently are used for the design of synthetic elements with higher-order imittance. Original conditions for the design of such blocks are given that lead to maximal simplicity of the final structure with minimal number of passive and active elements. For effective usage of another method utilizing signal flow-graphs, new reduced graphs of chosen active elements are given. Their usage leads to direct function blocks synthesis with required properties. The functionality and behavior of chosen circuit solutions have been verified by analyses in simulation programs. The active elements were simulated by the universal current conveyor (UCC) or universal voltage conveyors (UVC) that were designed at the FEEC, BUT in cooperation with AMI Semiconductor Design Centre Brno with the CMOS 0.35 m technology. These active elements have been also used for the realization of chosen filter structures. The experimental measurements were performed in the in the frequency range 10 KHz to 100 MHz.
3
Moghadam, Mansour Salehi. "Current-source-based low frequency inverter topology." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/12750.
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A DC to AC inverter can be classified in different topologies; some of these topologies are three level and multilevel inverter. Both types have some advantages and disadvantages. Three level inverters can be applied for low power applications because it is cheaper and has less semiconductor losses at high switching frequencies with poor total harmonic distortion (THD). Multilevel inverters (MLI) can be applied for higher power applications with less THD. However, the MLI has more cost and conductive power losses in comparison with three level inverters. In order to overcome the limitations of three and multilevel topologies, this thesis presents a new controlling topology of multilevel DC/AC inverters. The proposed multilevel inverter topology is based on a current source inverter, which consists of a buck/boost, boost and flyback converters, and an H-bridge inverter. The output voltage of the inverter is shaped through the control of just one main semiconductor switch. This new topology offers almost step-less output voltage without the need for multi DC source or several capacitor banks as in the case of other multilevel inverter topologies. The efficiency of the proposed topology is higher than other inverter topologies for medium power applications (2-10 kW). The proposed topology also generates smaller Total Harmonic Distortion (THD) compared to other inverter topologies. The two main key aspects of the proposed circuit is to keep the switching losses as low as possible and this is achieved through the control of a single switch at relatively low frequency and also to generate an improved AC Voltage waveform without the need for any filtering devices. The output frequency and voltage of the proposed circuit can be easily controlled according to the load requirements. The proposed inverter topology is ideal for the connection of renewable energy; this is due to its flexibility in varying its output voltage without the need of fixed turns-ratio transformers used in existing DC/AC inverter topologies. The harmonic contents of the output of this proposed topology can be controlled without the need of any filter. The simulation and practical implementation of the proposed circuits are presented. The practical and simulation results show excellent correlation.
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Williams, Mark Richard. "A controlled current inverter for an electric vehicle." Thesis, University of Canterbury. Department of Electrical and Electronic Engineering, 1993. http://hdl.handle.net/10092/2280.
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The University of 'Canterbury Mark II' electric vehicle has been out of service for
several years due to the lack of a suitable inverter to provide a variable frequency AC supply
to its traction motors.
This thesis describes the design and construction of such an inverter, using high
current bipolar junction transistors as the switching elements, so that the car might be
returned to service in the near future. The inverter is based on an existing commercial AC
motor speed controller. Modifications to this AC motor speed controller were made to suit
the low voltage, high current rating of the traction motors. These modifications are
described and it is shown that these modifications permitted the inverter to deliver the
required increase in current.
The inverter differs from most conventional AC motor speed controllers in that it acts
to shape load current rather than potential, and uses an asynchronous switching technique to
do this. The Thesis describes this technique and the control hardware constructed to
implement it.
Test results, showing the performance of the combined inverter/motor system are then
presented graphically and discussed with reference to standard AC motor theory, giving
consideration to the harmonic content of the AC waveforms. Consideration is also given to
a suitable closed-loop control system which could be expected to ensure that the inverter's
output frequency is controlled in such a manner as to give a safe and predictable response
to the brake and accelerator controls.
5
Hafed, Mohamed M. "CMOS inverter current and delay models incorporating interconnect effects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0025/MQ50614.pdf.
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Cho, Younghoon. "Multi-Branch Current Sensing Based Single Current Sensor Technique for Power Electronic Converters." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/39793.
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A new concept of current sensor reduction technique called multi-branch current sensing technique (MCST) is proposed in this dissertation. In the proposed current sensing method, one more branch currents are simultaneously measured several times in a single switching cycle by using a single current sensor. After that, the current reconstruction algorithm is applied to obtain all phase currents information. Compared to traditional single current sensor techniques (SCSTs), the proposed method samples the output of the current sensor regularly, and the current sensing dead-zone is dramatically reduced. Since the current sampling is performed periodically, its implementation using a digital controller is extremely simple. Moreover, the periodical dead-zone and the dead-zone near the origin of the voltage vector space which have been a big problem in the existing methods can be completely eliminated. Accordingly, there is no need to have a complicated vector reconfiguration or current estimation algorithm. The proposed MCST also takes the advantages of a SCST such as reduced cost and elimination of the sensor gain discrepancy problem in the multiple current sensor method. The fundamental concept, implementation issues, and limitation of the proposed MCST are described based on three-phase systems first. After that, the proposed MCST is adopted to two-phase inverters and multi-phase dc-dc converters with little modifications.
Computer simulations and hardware experiments have been conducted for a three-phase boost converter, a three-phase motor drive system, a two-phase two-leg inverter, a two-phase four-leg inverter with bipolar modulation, a two-phase four-leg inverter with unipolar modulation, and a four-phase dc-dc converter applications. From the simulations and the experimental results, the feasibilities of the proposed method mentioned above are fully verified.Ph. D.
7
White, Terence H. "A three-phase hybrid dc-ac inverter system utilizing hysteresis control." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FWhite%5FTerence.pdf.
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Abu-Khaizaran, Muhammad Sharif M. "The design of high power IGBT based current source inverter drive." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619760.
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Martinez, Marino Juan 1965. "The analysis of current-mirror MOSFETs for use in radiation environments." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276910.
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Experiments were conducted on current-mirror MOSFETs to examine their suitability for use in radiation environments. These devices, which allow low loss load current sensing (defined by a current-ratio n'), are an important element of many power integrated circuits (PICs). Total-dose testing demonstrated that the current ratio was virtually unaffected for many operating conditions. In all cases, changes were largest when sense resistance was largest and minimal when sense voltage was approximately equal to the load source's voltage. In addition, testing verified the feasibility of using sense-cell MOSFETs for applications which require radiation exposure. A constant-current op-amp circuit showed minimal current shifts, using proper circuit design, following total-dose exposure. Dose-rate testing showed the feasibility of using sense voltage to trigger g&d2; protection through drain-source voltage clamping, providing a relatively inexpensive alternative to voltage derating.
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Woolaghan, Stephen John. "Current source inverters for PM machine control." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/current-source-inverters-for-pm-machine-control(cf31f106-f7b5-475d-a5c1-8da80c06fc8a).html.
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Brushless permanent magnet (PM) drive systems offer a high efficiency over a wide power/torque-speed operating envelope, however, there are a number of problems that may limit, or complicate, their operation particularly in automotive and aerospace vehicular applications, i.e. the loss of control of the power silicon gate drive circuitry during fluxweakening operation, control of high-speed low-inductance machines and the presence of large electrolytic capacitors on the inverter DC link. Current Source Inverters (CSIs) could potentially address some or all of the above issues. However, they have found little application to date due to the wide use of the Voltage Source Inverter (VSI) circuit topology.This thesis investigates feasibility of utilising Current Source Inverters (CSIs) to control permanent magnet synchronous machines in automotive and aerospace actuation systems. CSIs, switching at the fundamental frequency, were used in some of the first semiconductor based, electronic variable speed drive systems that utilised the simple, low maintenance AC induction motor. However, the rapid progress of semiconductors and discovery of Pulse Width Modulation (PWM) techniques soon resulted in the Voltage Source Inverter (VSI) replacing the CSI in all but the highest power applications. Modern power electronics and (micro-processor based) control systems mean that the advantages of VSI systems may no longer be significant and combined with the unique environmental conditions that automotive and aerospace applications present, could allow the CSI to offer advantages over VSIs in these applications.The thesis presents the switching and control logic for CSIs and mapping to the more conventional VSI logic. Analysis is made of the various loss mechanisms in VSI and CSI power circuitary. Simulation models of the VSI and CSI structures are presented and representative drive systems designed, built and tested to validate the model developed. Comparisons are made of the two inverter topologies based on power conversions and loss audits of the test validation hardware.
11
Norman, Rosemary Anne. "High-performance current regulation for voltage-source-inverter-fed induction motor drives." Thesis, University of Bradford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514187.
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Martin, Henrik. "Control and current sensing systems for the parallel resonant pole inverter architecture." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37516.
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Hussien, Zahrul Faizi. "Current control of three-phase PWM Inverter for flywheel energy storage system." Thesis, University of Southampton, 2000. https://eprints.soton.ac.uk/47946/.
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The thesis is concerned with the use of flywheel energy storage system (FESS) in utility load levelling application. The work presented consists of two parts, first, an evaluation of utility load levelling schemes with FESS as the energy storage medium, and second, the development of power electronic interface of FESS to the utility. The thesis presents a study to evaluate FESS load levelling schemes in a UK electricity supply and distribution company. It identifies and quantifies the costs and benefits of the schemes, and carries out a financial appraisal based on Net Present Value (NPV) and Internal Rate of Return (IRR) methods. The results indicate that the DSM schemes utilising FESS can be financially viable for a UK electricity supply and distribution business in a mass-produced (low-cost) FESS scenario, and provide FESS manufacturers and developers with cost goals for such applications. The conclusions drawn provide the motivation for further technical research undertaken within the programme of work. The main work presented is in the area of power electronic interface between FESS, as well as other energy storage devices or energy sources, and the utility for embedded generation. The thesis particularly focuses on the design of current controllers for an interface in the form of three-phase voltage-source pulsewidth modulated (VS-PWM) inverter connected to the utility via LCL filter. Two different current controller structures based on suboscillation current control method have been analysed and designed, aided by computer simulation studies carried out using a general purpose dynamic system simulation software, Matlab Simulink. General properties of a three-phase VS-PWM inverter have been investigated to establish a basic understanding of its operation. The phenomenon of phase interaction in a system with no neutral connection has been examined and the effect of practical inverter nonlinearities caused by interlock time delay (dead time) and on-state voltage drops of the semiconductor devices has been discussed. Various PWM current control techniques have been investigated, including the three-independent hysteresis current control, advanced hysteresis current control, suboscillation current control and space vector current control. The suboscillation current control method has been chosen as produces a well defined harmonic spectrum in the output current without the need for complicated computations and extensive hardware, and can be easily implemented in analogue to avoid problems •sampling and computation time delay generally associated with digital controllers. Fundamental appreciation of the suboscillation PWM technique has been established from analytical synthesis of the modulation process, providing a rational basis for the current controller and computer simulation model validation. An inherent disadvantage of the suboscillation control method has been found to be its limited controller gain, causing a steady-state error to and the effect of inverter nonlinearities to be quite significant. In the first current controller structure, a simple compensation has been utilised to enable the gain to be increased beyond the conventional limit. Simulation results show that the steady-state error the current waveform has been improved and the effect of inverter nonlinearities has been It also makes the current controller less susceptible to the inherently noisy environment, current controller has been experimentally built and tested to validate the simulation results and to validate the practical aspects of its implementation. In the second current controller structure, a cyclic feedback system based on Iterative Control (ILC) has been utilised to eliminate the periodic error in the current waveform. The structure is more complicated and the cyclic feedback system requires digital implementation. Simulation results indicate that the cyclic feedback system is effective in eliminating periodic error in the current waveform. Due to time constraints and hardware limitations, ital implementation of the system has not been possible but is recommended for future research.
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Chen, Baifeng. "High-efficiency Transformerless PV Inverter Circuits." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/56686.
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With worldwide growing demand for electric energy, there has been a great interest in exploring photovoltaic (PV) sources. For the PV generation system, the power converter is the most essential part for the efficiency and function performance. In recent years, there have been quite a few new transformerless PV inverters topologies, which eliminate the traditional line frequency transformers to achieve lower cost and higher efficiency, and maintain lower leakage current as well.
With an overview of the state-of-the-art transformerless PV inverters, a new inverter technology is summarized in the Chapter 2, which is named V-NPC inverter technology. Based this V-NPC technology, a family of high efficiency transformerless inverters are proposed and detailly analyzed. The experimental results demonstrate the validity of V-NPC technology and high performance of the transformerless inverters.
For the lower power level transformerless inverters, most of the innovative topologies try to use super junction metal oxide semiconductor field effect transistor(MOSFET) to boost efficiency, but these MOSFET based inverter topologies suffer from one or more of these drawbacks: MOSFET failure risk from body diode reverse recovery, increased conduction losses due to more devices, or low magnetics utilization. By splitting the conventional MOSFET based phase leg with an optimized inductor, Chapter 3 proposes a novel MOSFET based phase leg configuration to minimize these drawbacks. Based on the proposed phase leg configuration, a high efficiency single-phase MOSFET transformerless inverter is presented for the PV micro-inverter applications. The PWM modulation and circuit operation principle are then described. The common mode and differential mode voltage model is then presented and analyzed for circuit design. Experimental results of a 250 W hardware prototype are shown to demonstrate the merits of the proposed MOSFET based phase-le and the proposed transformerless inverter.
New codes require PV inverters to provide system regulation and service to improve the distribution system stabilization. One obvious impact on PV inverters is that they now need to have reactive power generation capability. The Chapter 4 improves the MOFET based transformerless inverter in the Chapter 3 and proposed a novel pulse width modulation (PWM) method for reactive power generation. The ground loop voltage of this inverter under the proposed PWM method is also derived with common mode and differential mode circuit analyses, which indicate that high-frequency voltage component can be minimized with symmetrical design of inductors. A 250-W inverter hardware prototype has been designed and fabricated. Steady state and transient operating conditions are tested to demonstrate the validity of improved inverter and proposed PWM method for reactive power generation, high efficiency of the inverter circuit, and the high-frequency-free ground loop voltage.
Besides the high efficiency inverter circuit, the grid connection function is also the essential part of the PV system. The Chapter 5 present the overall function blocks for a grid-connected PV inverter system. The current control and voltage control loop is then analyzed, modeled, and designed. The dynamic reactive power generation is also realized in the control system. The new PLL method for the grid frequency/voltage disturbance is also realized and demonstrate the validity of the detection and protection capability for the voltage/frequency disturbance.
At last, a brief conclusion is given in the Chapter 6 about each work. After that, future works on device packaging, system integration, innovation on inverter circuit, and standard compliance are discussed.Ph. D.
15
Tian, Feng. "Pulse Frequency Modulation ZCS Flyback Converter in Inverter Applications." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4266.
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Renewable energy source plays an important role in energy co-generation and distribution. A traditional solar-based inverter system has two stages cascaded, which has simpler controller but low efficiency. A new solar-based single-stage grid-connected inverter system can achieve higher efficiency by reducing the power semiconductor switching loss and output stable and synchronizing sinusoid current into the utility grid. In Chapter 1, the characteristic I-V and P-V curve of PV array has been illustrated. Based on prediction of the PV power capacity installed on the grid-connected and off-grid, the trends of grid-tied inverter for DG system have been analyzed. In Chapter 2, the topologies of single-phase grid-connect inverter system have been listed and compared. The key parameters of all these topologies are listed in a table in terms of topology, power decoupling, isolation, bi-directional/uni-directional, power rating, switching frequency, efficiency and input voltage. In Chapter 3, to reduce the capacitance of input filter, an active filter has been proposed, which will eliminate the 120/100Hz low frequency ripple from the PV array's output voltage completely. A feedforward controller is proposed to optimize the step response of PV array output voltage. A sample and hold also is used to provide the 120/100Hz low frequency decoupling between the controller of active filter and inverter stage. In Chapter 4, the single-stage inverter is proposed. Compared with conventional two-stage inverter, which has two high frequency switching stages cascaded, the single-stage inverter system increases the system efficiency by utilizing DC/DC converter to generate rectified sinusoid voltage. A transformer analysis is conducted for the single-stage inverter system, which proves the transformer has no low-frequency magnetic flux bias. To apply peak current mode control on single-stage inverter and get unified loop gain, adaptive slope compensation is also proposed for single-stage inverter. In Chapter 5, a digital controller for single-stage inverter is designed and optimized by the Matlab Control Toolbox. A Psim simulation verified the performance of the digital controller design. In Chapter 6, three bi-directional single-stage inverter topologies are proposed and compared. A conventional single-stage bi-directional inverter has certain shortcoming that cannot be overcome. A modular grid-connect micro-inverter system with dedicated reactive energy processing unit can overcome certain shortcoming and increase the system efficiency and reliability. A unique controller design is also proposed. In Chapter 7, a PFM ZCS flyback inverter system is invented. By using half-wave quasi-resonant ZCS flyback resonant converter and PFM control, this topology completely eliminates switching loss. A detailed mathematical analysis provides all the key parameters for the inverter design. As the inductance of transformer secondary side get smaller, the power stage transfer function of PFM ZCS flyback inverter system demonstrates nonlinearity. An optimized PFM ZCS flyback DC/DC converter design resolves this issue by introducing a MOSFET on the secondary side of transformer. In Chapter 8, experimental results of uni-direcitonal single-stage inverter with grid-connection, bi-directional single-stage inverter and single-stage PFM ZCS flyback inverter have been provided. Conclusions are given in Chapter 9.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
16
Photong, Chonlatee. "A current source inverter with series AC capacitors for transformerless grid-tied photovoltaic applications." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13128/.
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The Current Source Inverter (CSI) is one of the simplest power converter topologies that can convert DC to AC and feed power generated from photovoltaic (PV) cells into the AC grid with a single power conversion stage over the whole PV voltage range. The CSI also provides smooth DC current which is one of the requirements of the PV cells as well as preventing reverse current using unidirectional switches. However, the CSI operates with low efficiency at lower PV voltages, which is where the PV cells produce maximum output power. This low efficiency is caused by large differences in voltage levels between the PV side and the grid side across the converter. This thesis presents an alternative topology to the three-phase CSI by connecting an AC capacitor in series with each AC phase line of the CSI circuit. The presence of the series AC capacitors in the CSI topology allows the AC voltage levels to be adjusted to match the voltage levels of the PV cells. Therefore, the CSI with series AC capacitors is able to operate with optimal DC-AC voltage levels. Performance of the proposed topology is evaluated in comparison to the standard CSI and five other converter topologies based on transformerless circuit concepts selected from those already available in the market and suitable converters discussed in the literature. All converter topologies were modeled and simulated with the SABER simulation software package. The CSI with series AC capacitors prototype was constructed in order to validate the feasibility of the proposed topology and the performance of the proposed topology in comparison to the standard CSI. Simulation results show that the CSI with series AC capacitors provides improved efficiency and better input/output power quality in comparison to the standard CSI. The proposed topology also achieves the lowest output line current distortion, lowest voltage stress across the circuit components and lowest estimated cost of power semiconductors when compared to all considered topologies. Experimental results are also presented to validate the simulation results.
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Singh, Akanksha. "A boost current source inverter based generator-converter topology for direct drive wind turbines." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/34676.
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Doctor of PhilosophyDepartment of Electrical and Computer Engineering
Behrooz Mirafzal
In this dissertation, a new topology for Direct-Drive Wind Turbines (DDWTs) with a new power electronics interface and a low-voltage generator design is presented. In the presented power electronics interface, the grid - side converter is replaced by a boost Current Source Inverter (CSI) which eliminates the required dc-bus capacitors resulting in an increase in the lifetime of DDWTs. The inherently required dc-link inductor for this topology is eliminated by utilizing the inductance of the Permanent Magnet Synchronous Generator (PMSG). The proposed three-phase boost CSI is equipped with Reverse-Blocking IGBTs (RB-IGBT) and the Phasor Pulse Width Modulation (PPWM) switching pattern to provide a 98% efficiency and high boost ratios ([superscript V]LL/V[subscript dc]) up to 3.5 in a single stage. In this dissertation, Phasor Pulse Width Modulation (PPWM) pattern for the boost – CSI is also modified and verified through simulation and experimental results. In order to realize potential capabilities of the boost inverter and to assist its penetration into renewable energy systems, the boost inverter dynamic behaviors are studied in this dissertation. Then, the developed models are verified using circuit simulations and experiments on a laboratory-scale boost – CSI equipped with RB-IGBTs. The developed dynamic models are used to study the stability of the boost – CSI through root locus of small signal poles (eigenvalues) as control inputs and load parameters vary within the boost inverter's operating limits. The dynamic models are also used to design the control schemes for the boost – CSI for both stand-alone and grid-tied modes of operation. The developed controllers of the boost – CSI are verified through simulation and experimental results. In this dissertation, the boost – CSI steady-state characterization equations are also developed and verified. The developed boost – CSI is used to replace the grid - side converter in a DDWT. A reliability analysis on the power electronics interface of an existing and developed topology is presented to demonstrate the increase in the mean time between failures. The boost – CSI enables conversion of a low dc voltage to a higher line-to-line voltage enabling the implementation of a low-voltage generator. This further enables a reduction in the number poles required in DDWT generators. The feasibility of the presented low-voltage generator is investigated through finite element computations. In this dissertation, a 1.5MW low-voltage generator designed for the proposed topology is compared with an existing 1.5MW permanent magnet synchronous generator for DDWTs to demonstrate the reduction in the volume, weight, and amount of permanent magnet materials required in the generator. The feasibility of the developed system is supported by a set of MATLAB/Simulink simulations and laboratory experiments on the closed-loop stand-alone and grid-tied systems.
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Ahmed, Eshita. "Hybrid Renewable Energy System Using Doubly-Fed Induction Generator and Multilevel Inverter." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26501.
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The proposed hybrid system generates AC power by combining solar and wind energy converted by a doubly-fed induction generator (DFIG). The DFIG, driven by a wind turbine, needs rotor excitation so the stator can supply a load or the grid. In a variable-speed wind energy system, the stator voltage and its frequency vary with wind speed, and in order to keep them constant, variable-voltage and variable-frequency rotor excitation is to be provided. A power conversion unit supplies the rotor, drawing power either from AC mains or from a PV panel depending on their availability. It consists of a multilevel inverter which gives lower harmonic distortion in the stator voltage. Maximum power point tracking techniques have been implemented for both wind and solar power. The complete hybrid renewable energy system is implemented in a PSIM-Simulink interface and the wind energy conversion portion is realized in hardware using dSPACE controller board.
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Un, Emre. "Common Mode Voltage And Current Reduction In Voltage Source Inverter Driven Three Phase Ac Motors." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609062/index.pdf.
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In this thesis various reduced common mode voltage (RCMV) pulse width modulation (PWM) techniques and active/passive common mode voltage (CMV) reduction methods for voltage source inverter driven three-phase AC motors are theoretically and practically investigated. A novel RCMV-PWM method, the near state PWM (NSPWM) method is proposed for operation at high modulation index. At low modulation index, a modified version of an existing RCMV-PWM method, AZSPWM1, termed as MAZSPWM, is proposed to mitigate the voltage reflection problem of the method. An optimum modulation algorithm combining NSPWM and MAZSPWM with seamless transition is proposed. The proposed RCMV-PWM methods significantly reduce CMV but they suppress common mode current (CMC) partially. Utilization of a common mode inductor together with RCMV-PWM methods is effective in suppressing the CMC. In the study, in addition to the CMV characteristics, various practical performance characteristics such as voltage linearity, inverter output current ripple, inverter DC-link current ripple, and output line-to-line voltage pulse pattern are also analyzed. The study involves analysis, computer simulations, and detailed laboratory experiments.
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Jacobs, D. M. (Danver Maxwill). "Voltage control of medium to high power three-phase inverter supply systems." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52608.
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Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: In this thesis a new voltage control method is developed for a three-phase inverter supply system. The inverter supply system consist of a Permanent Magnet Generator, a three-phase rectifier, a three-phase inverter plus LC-filter and a three-phase transformer in series. This system supplies power to a network or to a stand-alone load. The main focus of this thesis is on the control aspects of the inverter and the LC-filter. Different voltage control systems are investigated and compared to each other. From these methods the proposed voltage control method is developed where only the output voltages are measured to establish good voltage control. All these voltage control methods are also simulated with a software package. The proposed voltage control method compares very well with other voltage control methods. The results that are obtained in the simulations are satisfactory. The proposed voltage control method is also implemented in an 8 kW laboratory scale model and, again, very good practical results are obtained. A TMS320F240 nsp controller is used to implement the proposed voltage control method. The controller compensates well for load steps, and these results compare well to an alternative voltage control method, which was also evaluated practically.
AFRIKAANSE OPSOMMING: In hierdie tesis IS 'n nuwe spanningsbeheermetode ontwikkel VIr 'n drie-fase wisselrigter kragtoevoerstelsel. Die wisselrigter kragtoevoerstelsel bestaan uit 'n Permanent Magneet Generator, 'n drie-fase gelykrigter, 'n drie-fase wisselrigter plus Le-filter, en 'n drie-fase transformator in serie. Hierdie stelsel voorsien krag aan 'n netwerk sowel as aan 'n alleenstaande las. Die hooffokus van hierdie tesis is op die beheeraspekte van die wisselrigter en Le-filter. Verskillende spanningsbeheermetodes is deeglik ondersoek en vergelyk met mekaar. Uit hierdie metodes is dan die voorgestelde beheermetode ontwikkel waar slegs die uittreespanning gemeet word om goeie spanningsbeheer te kan doen. Al hierdie spanningsbeheermetodes is dan gesimuleer met 'n sagteware pakket. Die voorgestelde spanningsbeheermetode vergelyk baie goed met die ander spanningsbeheermetodes. Die resultate verky in die simulasies is ook baie bevredigend. Die voorgestelde beheermetode is ook geïmplementeer op 'n 8 kW laboratorium skaalmodel en weereens is baie goeie praktiese resultate verky. 'n TMS320F240 DSP-beheerder is gebruik om die voorgestelde beheermetode mee te implementeer. Die beheerder kompenseer baie goed vir lastrappe en vergelyk ook goed met 'n ander spanningsbeheermetode wat prakties ge-evalueer is.
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Penny, John Robert. "The development of a controlled-current inverter system for use in high performance AC motor speed controllers." Thesis, University of Canterbury. Department of Electrical and Electronic Engineering, 1986. http://hdl.handle.net/10092/2396.
Full textAbstract:
AC induction motor speed control has traditionally involved
controlling the motor's input voltage and frequency through use of a
three phase pulse-width-modulating (PWM) controlled-voltage inverter,
where the inductive motor load acts as an integrating filter to smooth
out the motor input currents. This report describes the development of
a novel controlled-current inverter system in which the three phase
motor input currents are independently monitored the inverter
phases are independently switched to ensure that the three phase motor
currents are balanced three phase sinusoids at all times. It is shown
that a controlled-current inverter is capable of efficiently
controlling an AC induction motor's speed and torque through varying
the frequency and amplitude of the motor's input currents,
respectively.
Prototype controlled-current inverter systems have been
constructed and extensive testing carried out, with the systems'
performance being compared with that obtainable from controlledvoltage
inverter systems. It has been found that the
controlled-current system results in lower motor losses and much
reduced levels of audible motor noise.
Since it is intended to develop these prototype designs into
commercially viable industrial motor controllers, facilities have been
incorporated into the designs that are necessary features of all
modern motor controllers which are designed for use in an industrial
environment.
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Sadda, AlajaKumari, and Niraja Madavaneri. "A Study of Output Impedance Effects in Current-Steering Digital-to-Analog Converters." Thesis, Linköpings universitet, Elektroniksystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-87399.
Full textAbstract:
In this thesis, we have explained the different types of DAC (Digital-to-Analog) architectures and their advantages and disadvantages. We have mainly focused on current-steering digital-to-analog design for achieving high speed and high performance. The current-steering DAC is designed using binary weighted architecture. The benefits of this architecture is that it occupies less area, consumes less power and the number of control signals required are very less. The requirements for high speed and high performance DAC are discussed in detail. The circuit is implemented in a state-of-the-art 65 nm process, with a supply voltage of 1.2 V and at a sampling speed of 2 GHz. The resolution of the DAC is 8-bits. The design of 8-bit current-steering DAC converts 8 most significant bits (MSBs) into their binary weighted equivalent, which controls 256 unit current sources. The performance of the DAC is measured using the static and dynamic parameters. In communication applications the static performance measures such as INL and DNL are not of utmost importance. In this work, we have mainly concentrated on the dynamic performance characteristics like SNR (Signal to Noise Ratio) and SFDR (Spurious Free Dynamic Range). For measuring the dynamic parameters, frequency domain analysis is a better choice. Also, we have discussed how the pole-zero analysis can be used to arrive at the dynamic performance metrics of a unit element of the DAC at higher frequencies. Different methods were discussed here to show the effects of poles and zeroes on the output impedance of a unit element at higher frequencies, for example, by hand calculation, using Mathematica and by using cadence. After extensive literature studies, we have implemented a technique in cadence, to increase the output impedance at higher frequencies. This technique is called as “complimentary current solution technique”. This technique will improve the output impedance and SFDR compared to the normal unit element design. Our technique contains mostly analog building blocks, like, current mirrors, biasing scheme and switching scheme and few digital blocks like D-ff (D-flip flop). The whole system is simulated and verified in MATLAB. Dynamic performances of the DAC such as SNR and SFDR are found with the help of MATLAB.
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Alves, rodrigues Luis Gabriel. "Design and characterization of a three-phase current source inverter using 1.7kV SiC power devices for photovoltaic applications." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT030.
Full textAbstract:
Classiquement, la chaîne de conversion de l’énergie électrique des centrales photovoltaïques comporte un champ photovoltaïque (PV) délivrant une tension maximale de 1kV suivi d’un hacheur élévateur connecté à un onduleur de tension triphasé. Cette chaîne de conversion à deux étages (DC/DC + DC/AC) est ensuite raccordée sur le réseau moyenne tension au travers d’un transformateur BT/HTA. Dans l’objectif de simplifier les systèmes de conversion PV, ce travail de recherche s’intéresse à l’étude et la mise en œuvre d’une topologie DC/AC n’employant qu’un seul étage de conversion : l’Onduleur de Courant triphasé. Bien que relativement simple, l’Onduleur de Courant présente comme inconvénient majeur les pertes par conduction. Pour pallier ce problème, des interrupteurs à grand-gap au Carbure de Silicium (SiC) sont employés, ce qui permet de convertir de l’énergie de façon performante (η>98.5%) tout en gardant une fréquence de commutation élevée (plusieurs dizaines de kHz). Les modules à semi-conducteurs de puissance du marché n’étant pas compatibles avec ce type de convertisseur, des modules particuliers en SiC ont été développés dans le cadre de la thèse. La caractérisation dynamique de ces nouveaux modules est réalisée dans le but de servir de base à la conception d’un démonstrateur de l’Onduleur de Courant d’une puissance nominale de 60kW. Enfin, le rendement de la partie semi-conducteur de puissance est évalué par une méthode calorimétrique confirmant l’aptitude de la topologie à fonctionner à des fréquences de commutation supérieures. L’originalité de ces travaux réside principalement dans la conception, caractérisation et mise en œuvre de ce nouveau module de puissance adapté à cette topologie connue, mais peu étudiée à l’heure actuelle avec des interrupteurs au SiCClassically, the energy conversion architecture found in photovoltaic (PV) power plants comprises a multitude of solar arrays delivering a maximum voltage of 1kV followed by a step-up chopper connected to a three-phase voltage source inverter. This two-stage conversion system (DC/DC + DC/AC) is then connected to the MV grid through a LV/MV transformer. In order to simplify the PV systems, this research work focuses on the study and implementation of a DC/AC topology employing a single conversion stage: the three-phase current source inverter (CSI). Although relatively simple, the CSI presents as major drawback the conduction losses. To deal with this problem, wide-bandgap silicon carbide (SiC) semiconductors are used, which allows to efficiently convert energy (η> 98.5%) while keeping a relatively high switching frequency (several tens of kHz). Nonetheless, since the available power semiconductor modules on the market are not compatible with the CSI, a novel 1.7kV SiC-based module is developed in the context of the thesis. Thus, the dynamic characterization of the new SiC device is carried out and serves as a basis for the design of a 60kW Current Source Inverter prototype. Finally, the inverter’s semiconductor efficiency is evaluated through a calorimetric method, confirming the ability of the topology to operate at higher switching frequencies. At the present time, little research has been conducted on the CSI implementation with SiC devices. The originality of this work lies mainly in the design, characterization and implementation of the new SiC power module adapted to this well-known inverter topology
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Zhao, Zhao [Verfasser], Roberto [Gutachter] Leidhold, and Ralf [Gutachter] Vick. "Common-mode current reduction technologies in four-wire inverter-fed motors / Zhao Zhao ; Gutachter: Roberto Leidhold, Ralf Vick." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2021. http://d-nb.info/1239811497/34.
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Murray, Nicholas John. "Flexible Power control in Large Power Current Source Conversion." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/2610.
Full textAbstract:
This thesis describes a new concept, applicable to high-power current-sourced conversion (CSC), where a controllable firing-angle shift is introduced between series and parallel converters to enable independent active and reactive power control. The firing-shift concept solves a difficult problem, by giving thyristor based CSCs the control flexibility of pulse-width modulated (PWM) converters, but without a loss in efficiency or rating. Several configurations are developed, based on the firing-shift concept, and provide flexible, efficient solutions for both very high power HVDC transmission, and very high current industrial processes.
HVDC transmission configurations are first developed for 4-quadrant high-pulse operation, based on the series connected multi-level current reinjection (MLCR) topology. Independent reactive power control between two ends of an HVDC link are proven under firing-shift control, with high-pulse operation, and without on-load tap changing (OLTC) transformers. This is followed by application of firing-shift control to a bi-directional back-to-back HVDC link connecting two weak systems to highlight the added dc voltage control flexibility of the concept.
The fault recovery capability of an MLCR based ultra-HVDC (UHVDC) long distance transmis-sion scheme is also proven under firing-shift control. The scheme responds favourably to both ac disturbances and hard dc faults, without the risk of commutation failures and instability experienced during fault recovery of line-commutated conversion.
The two-quadrant capability of very high current rectification is also proven with configurations based on phase-shifted 12-pulse and MLCR parallel CSCs. The elimination of the electro-mechanical OLTC/satruable reactor voltage control, the high-current CSC’s biggest shortcoming, greatly improves controllability and with firing-shift control, ensures high power-factor for all load conditions. This reduces the reactive power demands on the transmission system, which results in more efficient power delivery
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Titiz, Furkan Kaan Verfasser], Doncker Rik W. [Akademischer Betreuer] [De, and Sibylle [Akademischer Betreuer] Dieckerhoff. "A three-phase low-voltage grid-connected current source inverter / Furkan Kaan Titiz ; Rik W. de Doncker, Sibylle Dieckerhoff." Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1216040907/34.
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Thulukkameetheen, Mohideen Raiz. "Highly Linear Current to Delay converter and its application in ADC design." 2014. http://hdl.handle.net/10222/44103.
Full textAbstract:
In this work a low voltage and highly linear current-mode current to delay (CTD) converter is presented. The proposed current to delay converter has the improved linearity of about 23.5% when compared with a conventional–delay inverter over the input dynamic current range of 50µA. When used as front-end block in current-mode delay-mode analog to digital converter an 11-bit resolution is obtained. The design is implemented in TSMC 90 nm CMOS technology. Monte Carlo analysis and process corner analysis is performed on the proposed circuit to analyze the amount of mismatch that will degrade the performance of the circuit in a system level. A Process, Voltage, and Temperature (PVT) variation insensitive circuit is used to bias the designed CTD converter to obtain 57% reduction of variation when compared with the simple current mode biasing technique.
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Moschopoulos, Gerasimos. "A modified pulsewidth modulated current source inverter." Thesis, 1991. http://spectrum.library.concordia.ca/4579/1/MM73682.pdf.
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陳建銘. "Design of Current Mirror with High Output Impedance and High Current." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01553115579551644936.
Full textAbstract:
碩士建國科技大學
電機工程系暨研究所
99
The present paper mainly research current mirror with high current and high output impedances. Such a current mirror applied to OP amplifier, compared to regular current mirror, has high output impedances, current matching. Mainly, the software HSPICE on workstation is used for the circuit design. The devises in circuits are offered by National Chip Implementation Center. Under the 0.35μm regular processes of Taiwan Semiconductor Manufacture Cooperator, this paper is going to investigate, design, and compare.
30
Ho, Duen-Yi, and 何敦逸. "Study and Implementation of a Current-Source Inverter." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/17813417804908319447.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
92
The purpose of this thesis is to implement a current-source inverter with high current output capability. This current-source inverter serves as an ac power supply for electrical welding. First of all, we present four topologies of the power stages. After comparing among these four types, two of them：the full-bridge and the five-switch topologies are adopted for experiments. The control circuits of the chosen topologies are implemented with two schemes：utilizing either a single-chip microprocessor 8051, or integrated circuits. In high power systems, usually IGBT is used as the switching device which is considered to be the most important but vulnerable power electronic device. We also discuss on some topics such as the IGBT characteristics, driving circuits and noise suppression in high current systems. At last, we implement a prototype current-source inverter with its output current amplitude ranging from 0 to 100 A, frequency from 50 Hz to 200 Hz and the duty cycle from 10% to 90%.
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黃建銘. "The 0.35um CMOS Current Mirror Design and Analysis." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/25868250176903282898.
Full textAbstract:
碩士建國科技大學
電機工程系暨研究所
99
The present paper mainly design low voltage current supply circuit, whose properties are high swing, high output impedances, constant output current. In the research, the designed current supply has the properties of low voltage work, proper temperature coefficient compensate, and stable operation. Mainly, the software HSPICE on workstation is used for the circuit design. The devises in circuits are offered by National Chip Implementation Center. Under the 0.35μm regular processes of Taiwan Semiconductor Manufacture Cooperator, this paper is going to investigate, design, and compare.
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Chung, Chun-Fu, and 鍾俊甫. "Design and application of high accurate current mirror." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/56162979486518665542.
Full textAbstract:
碩士淡江大學
電機工程學系
89
As the current-mode approach to analog circuit design is gaining interest due to better performance, another compelling reason for current-mode circuit is the decreasing power supply of microelectronic, and much work has been carried out on current-output-based active devices (COBADs), such as current conveyors and OTAs. A current output stage (COS) is one of the main building blocks of COBADs, both linearity and output resistance of a COS depend on the performance of the current mirrors (CMs) used and both must be sufficiently high. In this thesis, a new current mirror is proposed to provide high accuracy and very high output impedance. A novel feedback gain stage is used to increase the output impedance and matching accuracy significantly. Moreover, the proposed new current mirror also has output swing similar as traditional two-stage cascode current mirror, and we used TSMC 0.35um 1P4M to simulate the performance and we would compare the performance between the novel current mirror and the general current mirror. this novel current mirror would be used in delay generator circuit to compare the performance with other current sources.
33
Pua, Mei-ping. "The design of a precision current mirror using a high-gain current amplifier." 2008. http://hdl.handle.net/10106/1875.
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Wu, Yu-En, and 吳毓恩. "Parallel Inverter System with Current-Weighting-Distribution-Control Strategy." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/69746580560803616884.
Full textAbstract:
博士國立中正大學
電機工程所
93
ABSTRACT A current-weighting-distribution-control (CWDC) strategy for multi-inverter systems to achieve current sharing is presented in this dissertation. With the CWDC strategy, the inverters connected in parallel are allowed to have different power ratings and can achieve a weighted-output-current distribution by adding only simple circuits to each inverter. In such systems, each inverter has an outer-voltage-loop controller to govern system stability, an inner-current-loop controller to expedite dynamic response, and a weighting-current controller to achieve current distribution and to reduce possible interactive effects among inverters. Simulation results and experimental measurements from a three-inverter and six-inverter systems with either identical or different power ratings have demonstrated the feasibility of the proposed strategy in weighting-current distribution and fast regulation during a step-load change or hot-swap operation. Finally, the regular CWDC strategy with Voerr-sharing scheme is proposed to improve weighting-current distribution and system dynamic response during load variations. The Voerr-sharing scheme is constituted by a Voerr-distribution circuit and used to share the Voerr signal according to the power rating of each inverter. Thus, the proposed multi-inverter system possesses the features of high reliability, expandability and maintainability. In addition, weighting-current distribution is more precise and the dynamic response is faster over the regular CWDC strategy.
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You-ChiangLin and 林右鎗. "Study on Grid-Connected Inverter with Current Correction Control." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/07765574948330368166.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
98
The purpose of this thesis is to implement the grid-connected inverter system to feed electrical power into the utility grid effectively by using current correction control. It work on stand-alone mode or grid connected mode. The inverter output voltage can be stable when operates in stand-alone mode with voltage feedback control. When the system operates in the grid-connected mode with zero-crossing control ＆ current correction control, the phase and frequency of the inverter output currents is similar to the utility system. Besides, this inverter with over-voltage or under-voltage protection can avoid system causing damage under improper operation. This system based on DSP TMS320LF2407A to fulfill digital control. And the prototype of inverter system is confirmed to be feasible.
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Mufford, William Edward. "Microcontroller-based current source inverter driven induction motor drive." Thesis, 1992. http://hdl.handle.net/2429/3087.
Full textAbstract:
Current Source Inverter Induction Motor Drives (CSI-IM) are well suited to large power applications when regeneration is required. This thesis deals with the design and analysis of a flexible single chip microcontroller based CSI-IM drive. In order to demonstrate the merits of the adaptable microcontroller based system, two different types of outer loop speed/torque control strategies (Flux and Vector control) are discussed and discrete control laws are developed. Furthering the theme of microcontroller agility, two different types of inner loop current control scheme sare developed: simple proportional-integral feed back control, and direct model reference adaptive control (DMRAC) with feed forward back-electromotive-force (back-emf) compensation. The Vector and DMRAC is included not only to demonstrate the fact that high-performance control laws can be run on the microcontroller in real time, but also to show the benefits of these advanced control methodologies. The overall hardware and software development is discussed in detail. Experimental results, using a prototype unit,are presented to illustrate the potential of the microcontroller based CSI-IM drive.
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XIA, QI-NAN, and 夏啟南. "Current source pwm GTO inverter for induction motor drive." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/22587199355012955337.
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吳起行. "Study on Control of Current-Source-Inverter-Fed PMSM." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/03364454154233148293.
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碩士國立交通大學
電控工程研究所
101
This dissertation studies the control system of Current-Source-Inverter-fed PMSM. The Buck DC-DC current controller is used as an ideal current source on the DC side of Current-Source-Inverter. The parallel capacitors on the AC side of Current-Source- Inverter constitute LC low pass filters with the inductive coils of PMSM, and supply phase currents for PMSM in some switching states of CSI. We use SVPWM to generate the switch signal, and the method we use to set Dead-Time can ensure minimum switching transient and reduce the switching energy consumption. Besides, the Zero-Sequence- Injection technology of SVPWM can extend the range of linear modulation, and improve the utilization of DC bus. The principle and method of SVPWM on Current-Source- Inverter is analyzed in detail. In control strategy, we build the equivalent model of the DC side and the AC side of Current-Source-Inverter separately, and improve the control method to realize the control of Current-Source-Inverter-Fed PMSM. Furthermore, we deduce the design formulas of the parallel capacitors. And the simulation and experimental results are also provided to demonstrate the validity of this system both under steady state and load switching state.
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SU, JIN-SHAN, and 蘇金山. "Control and modeling of the controlled-current inverter drive." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/07440956214274948368.
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陳天祐. "The analysis and research of the 0.35μm current mirror." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01967711266939814486.
Full textAbstract:
碩士建國科技大學
電機工程系暨研究所
99
This paper mainly investigates and researches current mirror deeply. Focus on basic current mirror, Cascade current mirror, Wilson current mirror, the HSPICE software is used for simulation analysis and research. The effect will be research between different temperature and different NMOS length or width to the output currents of current mirrors. Mainly, the HSPICE made by Synopsys is applied to the research. As well, in the research, the devises are offered by National Chip Implementation Center, which are made by 0.35μm regular processes of Taiwan Semiconductor Manufacture Cooperator.
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Wang, Chi-Zong, and 王麒榕. "Current Mirror Driver For High Power LED Backlight Module." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/52308949484169102198.
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碩士國立清華大學
產業研發碩士積體電路設計專班
95
Abstract A novel implementation of temperature independent current reference is proposed in this thesis. Based on the traditional bandgap circuit, a current reference is realized by compensating the temperature performance of the resistor, which can start correctly and work properly with a power supply voltage above 1.5V. Thus, a current reference independent and power supply voltage variations is proposed. A regulated feedback cascode current mirror is also proposed in this thesis. The current mirror is composed of the following three parts: the high accurate current matching circuit, the regulated high output resistance circuit and the wide voltage swing input circuit.
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Liu, Chang-Yuan, and 劉昌遠. "Implementation of a Current Amplifier using Paralleled Dual-Module Current-Controlled DC/AC Inverter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/nzyxh7.
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碩士國立臺北科技大學
電力電子產業研發碩士專班
96
This thesis is concerned with the analysis and implementation of a paralleled dual-module current amplifier. A current amplifier with a dual modules connected in parallel is presented based on the interleave control, so as to increase the carrier frequency at output and hence to improve the dynamic response and decrease output current ripple, therefore the size of output filter will be reduced. Also, a current controller is added in each module to make the current flowing through modules evenly distributed in steady state. To facilitate the studies performed in this thesis, a DSP-based controller is constructed using a DSP TMS320F2812 manufactured by Texas Instruments. There are several benefits using DSP-based to implement the dual-module parallel current amplifier, such as to simplify hardware circuits, to generate flexible functions and to adapt changing environmental conditions, etc. For saving the execution time, all the routines are coded by assembly language. Finally, some experimental results have confirmed the validity of the proposed methods in paralleled dual-module current amplifier.
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Klabunde, Michael C. "Current control of a 3-level rectifier/inverter drive system." 1995. http://catalog.hathitrust.org/api/volumes/oclc/33156576.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1995.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 57-59).
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Lee, Yun-Jui, and 李昀叡. "Improvement of shunt-based current sensing and inverter overmodulation strategy." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/w9s5uu.
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碩士國立臺灣大學
機械工程學研究所
107
This thesis presents two improvements on the high speed machine drive during high PWM voltage modulation index. The first part concentrates on the voltage source inverter with shunt resistors for machine current measurement. The proposed technique solves the current sensing dead zone which typically occurs in high modulation index. Two methods are developed to minimize the current sensing dead zone. The first method is based on the selection of two suitable phases under three-phase current sensing topology. The sensing dead zone is improved during 0.2~0.95 modulation index. In addition, the second method is proposed for the current sensing when the modulation index is higher than 0.95. On the basis, the DPWM is implemented to obtain more current measurement window under the same modulation index. It is concluded that the total current harmonic distortion can be minimized under 60% for full region modulation. In addition to current sensing dead zone, the inverter overmodulation is another issue to limit the high speed drive when the modulation index is beyond 0.866. This issue results in the degraded dynamic response at high speed. Under this effect, the second part develops the overmodulation control strategy to improve the drive transient response. By manipulating d-axis current dependent on the PWM voltage command, the transient state of current control is improved while maintaining steady-state performance. All the proposed methods are verified based on a 300W and 8-pole high speed permanent magnet machine.
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Hsiang-YiChu and 朱湘儀. "Dual Buck Inverter with Constant Frequency Variable Hysteresis Current Control." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/90045155481958795728.
Full textAbstract:
碩士國立成功大學
電機工程學系
102
The purpose of this thesis is to implement a dual buck inverter for tide power transfer system. Because the change of front-end tide power transfer system output AC voltage could be varying and low. By realized the first stage of boost converter to rectify and boost the voltage, then convert power to the second stage of dual buck inverter. The thesis presents a new control strategy of constant frequency with variable hysteresis width. It can design the filter and choose power components easily when using the new type control. Compare to conventional hysteresis current control, by constant frequency variable hysteresis current control, it reduces the total harmonic distortion and the ripple of output voltage. Furthermore, it raises the system of power conversion efficiency. Finally, the thesis proposed a prototype 500 watt dual buck inverter system is implemented. The maximum efficiency of the system is 97% and THD is less than 2%.
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"CMOS current mode A/D converter with improved power efficiency using current mirror memory cells." 2004. http://library.cuhk.edu.hk/record=b5891950.
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Chi-Hong, Chan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 114-117).
Abstracts in English and Chinese.
Abstract --- p.i
摘要 --- p.iii
Acknowledgements --- p.iv
Table of Contents --- p.vi
List of Figures --- p.x
List of Tables --- p.xiii
Chapter 1. --- Introduction --- p.1
Chapter 1.1. --- System on a Chip (SoC) Design Challenges --- p.1
Chapter 1.2. --- Research Objective --- p.3
Chapter 1.3. --- Thesis Organization --- p.3
Chapter 2. --- Fundamentals of CMOS Current Mode A/D converters --- p.5
Chapter 2.1. --- Overview --- p.5
Chapter 2.2. --- Current Mode Signal Processing --- p.5
Chapter 2.2.1. --- Voltage Mode Circuit Design Technique --- p.5
Chapter 2.2.2. --- Current Mode Circuit Design Technique --- p.6
Chapter 2.2.3. --- First Generation (FG) SI Memory Cell vs. Second Generation (SG) SI Memory Cell --- p.7
Chapter 2.3. --- Ideal Nyquist Rate A/D converters --- p.9
Chapter 2.4. --- Static Performance Parameters --- p.13
Chapter 2.4.1. --- Differential Non-Linearity (DNL) --- p.13
Chapter 2.4.2. --- Integral Non-Linearity (INL) --- p.13
Chapter 2.5. --- Performance Parameters in Frequency Domain --- p.15
Chapter 2.5.1. --- Signal-to-Noise and Distortion Ratio (SNDR) --- p.16
Chapter 2.5.2. --- Effective Number of Bits (ENOB) --- p.16
Chapter 2.5.3. --- Spurious Free Dynamic Range (SFDR) --- p.16
Chapter 3. --- Proposed Current Mirror Memory Cell (CMMC) --- p.18
Chapter 3.1. --- Overview --- p.18
Chapter 3.2. --- Working Principle of CMMC --- p.18
Chapter 3.3. --- CMMC vs. FG SI Cells --- p.20
Chapter 3.4. --- Analog Delay Cell Implementation using the two kinds of memory cells --- p.21
Chapter 3.4.1. --- Delay Cell Implementation by FG Memory Cells --- p.22
Chapter 3.4.2. --- Delay Cell Implementation by CMMC --- p.23
Chapter 3.4.3. --- Simulation Results --- p.24
Chapter 3.5. --- Conclusion --- p.27
Chapter 4. --- Architectural Design of the 12-Bit CMOS A/D Converter --- p.28
Chapter 4.1. --- Overview --- p.28
Chapter 4.2. --- The Floating Analog-to-Digital Converter --- p.28
Chapter 4.3. --- Conversion Algorithm --- p.32
Chapter 4.4. --- Accuracy Considerations Due to Circuit Non-Idealities --- p.34
Chapter 4.4.1. --- Gain Error of Residual Generator --- p.34
Chapter 4.4.2. --- Offset Error of Residual Generator --- p.36
Chapter 4.5. --- Speed Consideration --- p.36
Chapter 4.6. --- Power Consumption vs. No. of Bits per Stage --- p.38
Chapter 4.7. --- Final Architectural Design --- p.40
Chapter 5. --- A/D Converter Implementation using CMMC --- p.41
Chapter 5.1. --- Overview --- p.41
Chapter 5.2. --- Current Sample-and-Hold --- p.41
Chapter 5.2.1. --- Signal Independent CFT Cancellation --- p.43
Chapter 5.2.2. --- Signal Dependent CFT Cancellation --- p.44
Chapter 5.2.3. --- Complete CFT Cancellation --- p.45
Chapter 5.2.4. --- CFT Cancellation by Transmission Gate --- p.45
Chapter 5.2.5. --- CFT Cancellation by Dummy Switches --- p.47
Chapter 5.3. --- Common Mode Feed Forward (CMFF) --- p.48
Chapter 5.4. --- Differential Current Comparator --- p.52
Chapter 5.4.1. --- Regenerative Latch --- p.53
Chapter 5.4.2. --- Pre-amplifier --- p.54
Chapter 5.5. --- Residual Generator --- p.55
Chapter 5.6. --- Thermometer to Binary code Decoder --- p.57
Chapter 6. --- Layout Considerations --- p.59
Chapter 6.1. --- Overview --- p.59
Chapter 6.2. --- Process Introduction --- p.59
Chapter 6.3. --- Common Centroid Layout --- p.60
Chapter 6.4. --- The Design of Power Supply Rails --- p.63
Chapter 6.5. --- Shielding --- p.64
Chapter 6.6. --- Layout of the whole design --- p.65
Chapter 7. --- Simulation Results --- p.67
Chapter 7.1. --- Overview --- p.67
Chapter 7.2. --- Simulation Results of the Current Sample-and-Hold --- p.67
Chapter 7.3. --- Simulation Results of the Differential Current Comparator --- p.70
Chapter 7.4. --- Simulation Results of the overall ADC using One-Stage Simulation Result --- p.71
Chapter 7.5. --- Power Simulation of the Overall 12-Bit ADC --- p.75
Chapter 7.6. --- Summary --- p.78
Chapter 8. --- Measurement Results --- p.79
Chapter 8.1. --- Overview --- p.79
Chapter 8.2. --- PCB Design Consideration --- p.79
Chapter 8.3. --- Measurement Setup --- p.82
Chapter 8.4. --- Measurement Result --- p.84
Chapter 8.4.1. --- Static Parameters --- p.84
Chapter 8.4.2. --- Frequency Domain Measures --- p.85
Chapter 8.5. --- Discussion --- p.90
Chapter 9. --- Conclusion --- p.95
Chapter 9.1. --- Research Methodology of this Project --- p.95
Chapter 9.2. --- Comparison between Voltage Mode and Current Mode Circuit --- p.97
Chapter 9.3. --- Contribution of this Project --- p.98
Chapter A. --- Appendices --- p.99
Chapter A.I. --- Small Signal Analysis on CMMC and FG Memory Cell --- p.99
Chapter A.II. --- The ESD Protection on the ADC --- p.102
Chapter A.III. --- The Histogram Test to determine the DNL and INL of ADC --- p.104
Chapter A.IV. --- Measurement Result of a Commercially Available ADC AD7820 --- p.106
Chapter A.V. --- Pin Assignment of the Current Mode ADC --- p.109
Chapter A.VI. --- Schematics of the Current Mode ADC --- p.111
Chapter A.VII. --- The Chip Micrograph --- p.113
Bibliography --- p.114
47
Banerjee, Debmalya. "Load Commutated SCR Current Source Inverter Fed Induction Motor Drive With Sinusoidal Motor Voltage And Current." Thesis, 2008. http://hdl.handle.net/2005/744.
Full textAbstract:
This thesis deals with modeling, simulation and implementation of Load Commutated SCR based current source Inverter (LCI) fed squirrel cage induction motor drive with sinusoidal voltage and sinusoidal current. In the proposed system, the induction motor is fed by an LCI. A three level diode clamped voltage source inverter (VSI) is connected at the motor terminal with ac chokes connected in series with it. The VSI currents are controlled in such a manner that it injects the reactive current demanded by the induction motor and the LCI for successful commutation of the SCRs in the LCI. Additionally, it absorbs the harmonic frequency currents to ensure that the induction motor draws sinusoidal current. As a result, the nature of the motor terminal voltage is also sinusoidal.
The concept of load commutation of the SCRs in the LCI feeding an induction motor load is explained with necessary waveforms and phasor diagrams. The necessity of reactive compensation by the active filter connected at the motor terminal for the load commutation of the thyristors, is elaborated with the help of analytical equations and phasor diagrams. The requirement of harmonic compensation by the same active filter to achieve sinusoidal motor current and motor voltage, is also described. Finally, to achieve the aforementioned induction motor drive, the VA ratings of the active filter (VSI) and the CSI with respect to VA rating of the motor, are determined theoretically. The proposed drive scheme is simulated under idealized condition. Simulation results show good steady state and dynamic response of the drive system. Load commutation of the SCRs in the LCI and the sinusoidal profile of motor current and voltage, have been demonstrated.
As in LCI fed synchronous motor drives, a special mode of operation is required to run up the induction motor from standstill. As the SCRs of the LCI are load commutated, they need motor terminal voltages for commutation. At standstill these voltages are zero. So, a starting strategy has been proposed and adopted to start the motor with the aid of the current controlled VSI to accelerate until the motor terminal voltages are high enough for the commutation of the SCRs in the LCI.
The proposed drive is implemented on an experimental setup in the laboratory. The IGBT based three level diode clamped VSI has been fabricated following the design of the standard module in the laboratory. A generalized digital control platform is also developed using a TMS320F2407A DSP. Two, three phase thyristor bridges with necessary firing pulse circuits have been used as the phase controlled rectifier and the LCI respectively. Appropriate protection scheme for such a drive is developed and adopted to operate the drive. Relevant experimental results are presented. They are observed to be in good agreement with the simulation results.
The effect of capacitors connected at the output of the LCI in the commutation process of the SCRs in the LCI is studied and analyzed. From the analysis, it is understood that the capacitors form a parallel resonating pair with filter inductor and the motor leakage inductance, which results in an undesired oscillation in the terminal voltage during each of the commutation intervals leading to commutation failure. So, in the final system, the capacitors are removed to eliminate any chance of commutation failure of the SCRs in the LCI. It is shown by experiment that the commutation of the SCRs takes place reliably in the absence of the capacitors also. The commutation process is studied and analyzed without the capacitors to understand the motor terminal voltage waveform of the experimental results.
48
Po-EnWang and 王伯恩. "Study on Parallel-Controlled Inverter System for Tidal Current Power Generation." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/87k2t2.
Full textAbstract:
碩士國立成功大學
電機工程學系
106
In this thesis, the digital parallel-controlled inverter system is developed. The control strategy of the system is the combination of constant voltage control and constant current control which can let the system operate both in standalone and grid-connected mode. The constant voltage control strategy is realized by translating the output voltage signal from the stationary frame into the rotating frame so that sinusoidal voltage can be treated as dc value to be regulated. The constant current control strategy is implemented based on dq reference frame. By means of Park transformation, sinusoidal current can be represented as dc value, rotating synchronously at the detected frequency provided by phase-locked loop so that the active power and reactive power can be controlled separately by dq current command. Furthermore, with the use of the proposed PLL consist of the structure based on a second order generalized integrator (SOGI), the phase angle can be tracked precisely. Finally, the parallel-controlled inverter system is realized and experimental results show that the system can supply up to 1000 W in standalone mode and 500 W in grid-connected mode.
49
Chen, Wei-Zhong, and 陳偉中. "Development of Single-phase Current Source Inverter for Ozonizer Power Supplies." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/s9e2up.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
107
This thesis aims to develop a high-voltage and high-frequency single-phase current source inverter power supply for ozonizer. The whole system is composed of an interleaved buck converter, a single-phase current source inverter and a RLC parallel resonant load. Interleaved buck converter as DC-DC converter uses a three-phase bridge rectifier to convert grid voltage to dc-link voltage. With controlling the output current of the interleaved buck converter, the features of constant output power and constant output current can be achieved. This control strategy could reduce the value of ripple of the output current and increase the system power capacity. Single-phase current source inverter converts direct current to alternating current, and connects with a transformer as a power supply for ozonizer. This RLC parallel resonant circuit can supply a high power factor and low switching loss output by working at the resonant frequency with the single-phase current source inverter. The 32-bit digital signal processor, TMS320F28069, is adopted as the system core. All control strategies are accomplished with C language, which can reduce hardware components. The ouput power of the system as power supply for ozonizer reaches to 1.0kW, the ouput current of the primary side of the transformer is 5.35A, the ouput voltage is 431V, and the weight percent of the ozone is 11.15%. The thesis also accomplished a system with a parallel resonant circuit to simulate ozonizer, which output power reaches to 2.0W. The output current is 7.84A, the output voltage is 263V, the output frequency is 1kHz, the output power factor is 0.99, and the system efficiency is 91%. The feasibility of the proposed system structure and control strategy is verified experimentally.
50
Yu-GuangWu and 吳育光. "Implementation of Grid-Connected Inverter for Tidal Current Power Generation System." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/09746864805974594797.
Full textAbstract:
碩士國立成功大學
電機工程學系專班
98
The design and implementation of grid-connected type inverter for tidal current power generation system is presented in this thesis. The output voltage would be stable in the default variation of input voltage. Because the input voltage will be varied in certain range, so a control procedure is made to reduce the influence to output voltage. Under stand-alone mode, the voltage feedback control is used to adjust the duty of pulse-width modulation and maintain output voltage in the default range. Under grid-connected mode, the current feedback control is used to limit output current for the purpose of output power control. Finally, the experimental result and PSIM simulation are presented to verify the control theorem and design procedure of inverter, and efficiency of inverter could be more the 91% under stand-alone mode.