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1
Demirkutlu, Eyyup. "Output Voltage Control Of A Four-leg Inverter Based Three-phase Ups By Means Of Stationary Frame Resonant Filter Banks." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608151/index.pdf.
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A method for high performance output voltage control of a four-leg inverter based three-phase transformerless UPS is proposed. Voltage control loop is employed and the method employs stationary frame resonant filter controllers for the fundamental and harmonic frequency components. A capacitor current feedback loop provides active damping and enhances the output voltage dynamic performance. The
controller design and implementation details are given. Linear and nonlinear loads for balanced and unbalanced load operating conditions are considered. The steadystate
and dynamic performance of the UPS are investigated in detail. A scalar PWM method with implementation simplicity and high performance is proposed and implemented. The control and PWM methods are proven by means of theory,
simulations, and experiments.
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Žůrek, Tomáš. "Řízení trojfázového sinusového zdroje." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220914.
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This thesis deals with control of three phase inverter as three phase sinusoidal voltage source for UPS application. Thesis is split to two parts, teoretical and practical. Teoretical part deals with three phase inverter topology analysis according requirement of neutral line wire and possibilities of generating sinusoidal PWM in depend of topology. There are also analysed properties of contorled system and designed 3 regulation methods with simulations. Second part of thesis deals with realisation of sinusoidal power source with inverter borrowed by Elcom company. To inverter control is used digital signal controler TMS320F28335 with implemented control algorithms. There are also presented the measurement results of the prototype of power source. In conclusion, simulation results are compared with measurements and achieved results are summarized.
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Yildirim, Dogan. "Field Oriented Control Of A Permanent Magnet Synchronous Motor Using Space Vector Modulated Direct Ac-ac Matrix Converter." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614302/index.pdf.
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The study designs and constructs a three-phase to three-phase direct AC&ndash<br>AC matrix converter based surface mounted permanent magnet synchronous motor (PMSM) drive system. First, the matrix converter topologies are analyzed and the state-space equations describing the system have been derived in terms of the input and output variables. After that, matrix converter commutation and modulation methods are investigated. A four-step commutation technique based on output current direction provides safe commutation between the matrix converter switches. Then, the matrix converter is simulated for both the open-loop and the closed-loop control. For the closed-loop control, a current regulator (PI controller) controls the output currents and their phase angles. Advanced pulse width modulation and control techniques, such as space vector pulse width modulation and field oriented control, have been used for the closed-loop control of the system. Next, a model of diode-rectified two-level voltage source inverter is developed for simulations. A comparative study of indirect space vector modulated direct matrix converter and space vector modulated diode-rectified two-level voltage source inverter is given in terms of input/output waveforms to verify that the matrix converter fulfills the two-level voltage source inverter operation. Following the verification of matrix converter operation comparing with the diode-rectified two-level voltage source inverter, the simulation model of permanent magnet motor drive system is implemented. Also, a direct matrix converter prototype is constructed for experimental verifications of the results. As a first step in experimental works, filter types are investigated and a three-phase input filter is constructed to reduce the harmonic pollution. Then, direct matrix converter power circuitry and gate-driver circuitry are designed and constructed. To control the matrix switches, the control algorithm is implemented using a DSP and a FPGA. This digital control system measures the output currents and the input voltages with the aid of sensors and controls the matrix converter switches to produce the required PWM pattern to synthesize the reference input current and output voltage vectors, as well. Finally, the simulation results are tested and supported by laboratory experiments involving both an R-L load and a permanent magnet synchronous motor load. During the tests, the line-to-line supply voltage is set to 26 V peak value and a 400 V/3.5 kW surface mounted permanent magnet motor is used.
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Dai, Min. "Control of power converters for distributed generation applications." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124329850.
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Pinto, Lázaro Rubens Araújo. "Aplicação de controlador preditivo baseado em modelo (MPC) para sistema de geração distribuída constituído por inversor trifásico a quatro braços." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7853.
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Previous issue date: 2017-08-07<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>This work proposes an analysis of the closed-loop operation of a distributed generation system connected to a three-phase four-wire AC power system by a three-phase four-leg inverter.
The modulation strategy adopted for this inverter is determined by the Model Predictive Control (MPC) method. Reasons for the use of this topology and the control method are discussed.
The chosen structure for the MPC predictive control aims to supply of active and reactive power by the inverter in order to maximize the power factor measured by the four-wire AC source (Y-n). Four possible cases of operation are reported for the analysis of the proposal in the three-phase four-leg inverter and other two cases for a three-phase full-bridge inverter (3F) for comparison purposes. Based on the monitoring of the active powers involved and the other variables of interest, it was possible to exemplify the achievement of the proposed objectives and validate the adopted method, at least under modeling and software simulation level.<br>Este trabalho propõe uma análise da operação em malha fechada de um sistema de geração distribuída para conexão em um sistema trifásico a quatro fios, a partir do controle de um inversor trifásico a quatro braços. A estratégia de modulação adotada para este inversor é determinada pelo método de controle preditivo baseado em modelo (MPC - Model Predictive Control). Justificativas para a utilização dessa topologia e do método de controle são discutidas. A estrutura escolhida para o controle preditivo MPC objetiva o fornecimento de potência ativa e reativa pelo inversor tendo em vista a maximização do fator de potência medido a partir da fonte pela fonte CA a quatro fios (Y-n). Quatro casos são abordados para análise da proposta no inversor trifásico a quatro braços e dois casos para um inversor trifásico em ponte completa (3F) para efeito de comparação. Baseando-se no monitoramento das potências elétricas envolvidas e nas demais grandezas de interesse, foi possível concluir que os resultados de simulações exemplificam o alcance dos objetivos propostos e validam o método adotado, pelo menos em relação à modelagem matemática empregada e à simulação do sistema de geração proposto em ambiente computacional.
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Chen, Chun-Hung, and 陳俊宏. "Study of a Novel Four-Switch Three-Phase Inverter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/88070340764126702697.
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碩士<br>國立宜蘭大學<br>電機工程學系碩士班<br>96<br>A novel four-switch three-phase inverter is designed and implemented. A low cost four main switches and four auxiliary switches power converter configuration of the three-phase inverter is proposed. All main switches in the three-phase inverter operate at zero voltage switching (ZVS) turn on and turn off. Also, the auxiliary switches operate at zero current switching (ZCS) turn on and turn off. Moreover, the reduction in the number of main switches can also increase the reliability, since the control circuits and the auxiliary circuits are there by reduced to two sets.
Therefore, the proposed power converter configuration achieves the low cost and high efficiency inverter without changing devices rate. The principle of operation, computer simulation and experimental results of the four-switch three-phase inverter, rated 200W and operated at 40kHz are provided to demonstrate the performance.
Keywords: Zero-Voltage Switching (ZVS), Zero-Current Switching (ZCS), Four-Switch Three-Phase Inverter (FSTPI)
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Chiu, Chi-Lun, and 邱啟倫. "Design and Implementation of Model-Free Predictive Current Controller for Four-Switch Three-Phase Inverter-Fed Synchronous Reluctance Motors." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/45034255736362108121.
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碩士<br>國立臺灣海洋大學<br>電機工程學系<br>103<br>This thesis presents a novel predictive current control for four-switch three-phase inverter-fed synchronous reluctance motor drive systems. We not only develop a new strategy for four-switch three-phase inverter-fed synchronous reluctance motor drive systems, but also discuss the feasibility and correctness of this method so as to improve the ability of the current control of the motor drive system. Furthermore, we expect to meet the industrial requirements of low-cost drive system equipped with high-performance current control. Compared to the six-switch drive system, the four-switch three-phase drive system can effectively reduce the development costs in both hardware and software. For a four-switch three-phase synchronous reluctance motor drive system, its switch strategies that we can choose are few. Generally speaking, the drawback of hysteresis current control is that it has large ripples in the output currents of the inverter. In order to improve the current-tracking performance, the development of the new switching strategy for low-cost drive system is urgently needed. As a result, the proposed method is based on the stator current measurement and the current variation so as to predict the future stator current. A digital signal processor, TMS320F2809, made by Texas Instruments Company, is used to execute the algorithms of the proposed predictive current control and hysteresis current control. Experimental results can be used as a reference for developing a new switching strategy of a four-switch three-phase drive system in the future.
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Peng, Chih-I., and 彭智義. "Design and Implementation of An Improved Predictive Current Controller for Four-Switch Three-Phase Inverter-Fed Synchronous Reluctance Motor Drive systems." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/d859f9.
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Chen, Ching-Chen, and 陳慶臻. "A multicarrier PWM for three-phase four-leg inverter." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/xk4kbd.
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碩士<br>中華大學<br>電機工程學系<br>106<br>Three-phase three-leg inverter has an inherent common mode voltage (CMV)
problem.Therefore, three-phase four-leg inverter is proposed to mitigate the CMV.
This study discusses the characteristics of multicarrier pulse width modulation (PWM)
for three-phase four-leg inverter. The analysis of sinusoidal PWM and space vector
PWM with multicarrier is presented. The simulation results are utilized to validate the
performances of the proposed multicarrier PWM scheme.
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Lin, Li-Chiun, та 林力群. "D-Σ Digital Control Based Three-Phase Four-Wire Inverter". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/8tee2e.
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博士<br>國立中正大學<br>電機工程研究所<br>103<br>This dissertation presents a division-summation (D-Σ) digital control for three-phase four-wire bi-directional inverters with wide inductance variation. The bi-directional inverters can fulfill grid connection, rectification and uninterrupted power supply (UPS). When AC grid is operated normally and the inverter system is connected to the grid, the system will be operated in grid-connection (GC) mode, which includes four functions: unity power factor (PF), rectification with pow-er-factor correction (PFC), PF leading and PF lagging. On the contrary, when the in-verter system is disconnected from AC grid due to grid fault, the system will be operated in UPS mode, supplying stable power continually for loads. The proposed D-Σ control summarizes the inductor-current variations over one switching cycle to derive control laws directly, which can overcome limitations of a-b-c to d-q transformation (Park transformation). With the proposed control, the inverter can track its sinusoidal reference currents or voltages, and it is allowed to have wide inductance variation, reducing core size significantly. In the literature, the D-Σ digital control for three-phase three-wire grid-connected inverters has been presented. However, the inverter with the previous control approach requires four control laws and four vector combinations, increasing the complexity of firmware programming. Since its region division is determined based on the zero-crossing point of line currents, the inverter is required to select different vector combinations corresponding to the phase shift between line currents and line voltages. To improve the limitations, the dissertation presents the improvement of the control-law derivation and region selection for the D-Σ digital control. By selecting the zero crossing points of phase voltages as region transitions, the control laws and the related parameter tables for the four modes can be unified to a general form. The switching sequences of the four modes are also unified to the switching pattern of the GC mode. Additionally, a D-Σ transformation matrix is identified to simplify the derivation procedure of the division (D) and summation (Σ), which can obtain the control law directly. To improve current distortion under low current levels, this dissertation presents three attempts, including mid-point current sampling, smooth region transition, current interleaving, and duty splitting. In the design and implementation, the inductances corresponding to various inductor currents are measured and tabulated into a single-chip microcontroller for tuning loop gain cycle by cycle, ensuring system stability.
For extending of the application of D-Σ digital control, this dissertation presents the D-Σ digital control based three-phase four-wire inverter which is adopted for uninterruptible power supply. The D-Σ digital control cannot be directly applied to voltage tracking inverter since the above control is a current tracking control. Thus, this dissertation proposes an impedance estimation to estimate the load current variation, and the D-Σ digital control based voltage tracking can be achieved. Moreover, a repetitive control is also included in the D-Σ control to reduce harmonic distortion. The repetitive control not only records the voltage error of the last line cycle, but uses the error to modify the next switching-cycle voltage control which can fine tune the voltage tracking more sinusoidally.
For a micro-grid application, this study combines the D-Σ current tracking and voltage tracking controls into the inverter operation, and the control strategies for mode transitions from GC mode to UPS mode and vice versa are presented. When connecting or disconnecting the grid, the two types of inverter operations can transit smoothly based on the proposed control strategies. Experimental results have con-firmed the discussions
The above controls are all based on an LC filter. However, high frequency ripple current injection to the grid cannot be avoided. Actually, there are grid impedance and grid-voltage harmonics, which result in harmonic current injection to the grid. To reduce grid current harmonics, this dissertation presents an improvement of LCL-filter design and control method based on the D-Σ digital control. Its feasibility has been verified from the measurement of a single-phase inverter and the simulation results of a three-phase four-wire inverter.
Keywords: Division-summation (D-Σ), digital control, three-phase inverter, induct-ance variation, impedance estimation, repetitive control, LCL-filter.
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Chang, Chen-Wei, and 張陳維. "A multicarrier PWM for unbalance three-phase four-leg inverter." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/p2a73t.
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碩士<br>中華大學<br>電機工程學系<br>106<br>The three-phase four-leg inverter is a system for mitigating common-mode voltages
better than three-phase three-arm inverters. Therefore, for the common mode voltage
(CMV), two techniques for three-phase four-arm inverters with multi-carrier pulse width
modulation (PWM), sinusoidal PWM (SPWM) and space vector PWM (SVPWM) are
proposed. To lower the CMV. This method is used to explore the impact on the system
under load imbalance. Finally, the experimental and simulation software PSIM platform is
used to analyze its system to verify the correctness of the proposed method.
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Yeh, Chia-hao, and 葉佳皓. "DSP-BASED INVERTER SYSTEMS WITH THREE-PHASE SWITCH-MODE RECTIFIER FRONT-END." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/29996390350649923648.
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碩士<br>國立清華大學<br>電機工程學系<br>97<br>This thesis develops some DSP-based isolated single- and three-phase inverters with switch-mode rectifier (SMR) front-end. The adequate control is conducted to yield good inverter output performance and satisfactory line drawn power quality. In the development of inverter systems, the designs, implementations and controls for the following plants are performed: (i) single-phase low-frequency (LF) and high-frequency (HF) isolated inverters; (ii) three-phase single-module LF and HF isolated inverters; (iii) three-phase LF isolated Y and Δ/V modular connected inverters. Some major features of these developed inverters lie in: (i) the robust current and voltage waveform controls are proposed to yield good and robust inverter output performance under changing and nonlinear loads; (ii) the HF isolation is achieved by an isolated intermediate DC/DC series resonant converter; (iii) the Δ-connected inverter can become V-connected one automatically as one constituted module is faulted.
As generally recognized, SMR is an indispensable power electronic equipment for AC to DC conversion with good power quality, and the three-phase one is a natural choice for higher power rating. This thesis develops a three-phase single-switch (3P1SW) and a three-phase Vienna SMR front-ends for the established inverters, and their comparative performance evaluation is made. The 3P1SW SMR operating in discontinuous conduction mode (DCM) is simpler in circuit and control scheme, but it suffers from having limited power quality characteristics. As to the Vienna SMR, it employs three power switches and operates under continuous conduction mode (CCM). Hence it possesses much better power conditioning control capability and power quality than those of 3P1SW SMR.
Key words: Single-phase inverter, three-phase inverter, modular connection, resonant converter, isolated DC-link, digital control, DSP, waveform control, transformer flux imbalance, switch-mode rectifier, power factor correction.
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Chen, Jr-Hung, and 陳志宏. "The Development of Four-Switch Three-Phase Linear Motor Drive." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/24397125468443398849.
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碩士<br>逢甲大學<br>電機工程所<br>94<br>The inverter is a kind of power electronics device. The speed on position control of a inverter can be adjusted by using the power supply voltage and frequency to the variable quantitied. With the development of high speed power semiconductor devices three-phase inverters play the key role for variable speed ac motor drives. Six-switch, three-phase inverters have been widely utilized for variable speed drives. Most of the past research drives mainly concentrated on the development of the efficient control algorithms for high performance drives. However, the cost did not get that much attention to the researchers, thus, a reduction of the number of power semiconductors in the inverter should be a main consideration. On this, thesis 4-switches, 3-phase inverter is proposed to control the permanent magnetism synchronous linear motor (PMSLM). This reduces the cost of the inverter, the switching losses, and the complexity of the control algorithms and interface circuits to generate 6 Pulse width Modulated (PWM) logic signals, compared with the traditional six-switch three phase inverter. Finally, a four-switch three phase inverter is implemented and demonstrated in this thesis.
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Huang, Jhen-Yu, and 黃振祐. "DEVELOPMENT OF ISOLATED THREE-PHASE INVERTER SYSTEMS WITH SWITCH-MODE RECTIFIER FRONT-ENDS." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/09115488328006999577.
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碩士<br>國立清華大學<br>電力電子產業研發碩士專班<br>98<br>The major purposes of this thesis are to develop a single-module high-frequency isolated three-phase inverter and a Scott-T modular connected low-frequency isolated three-phase inverter. All are equipped with different types of three-phase switch-mode rectifiers, and proper digital controls using digital signal processor (DSP) are conducted to yield good inverter output performance.
First, a single-phase inverter is designed and implemented, which possesses excellent and robust output voltage waveform tracking characteristics via the proposed sophisticated current and voltage control schemes. The established single-phase inverter is then employed to form a low-frequency isolated Scott-T modular connected three-phase inverter, only two inverter modules and a Scott-T transformer bank are employed. Some measured results are provided to demonstrate its operating performances, including voltage waveforms under unbalanced and nonlinear loads, and three-phase imbalance, etc. Second, a high-frequency isolated three-phase inverter is constructed. It consists of a single-module six-switch three-phase inverter and a LLC resonant DC/DC converter to establish the isolated DC-link with well-regulated voltage. The comparative performance evaluation for these two types of three-phase inverters is conducted. Specifically speaking, the high-frequency isolated inverter possesses less output voltage waveform distortion in powering nonlinear loads. However, its rating enlargement is more difficult owing to the inherent limits of high-frequency power transformer.
Finally, the development of three types of three-phase switch-mode rectifiers (SMRs) is made, and they are utilized to serve as the front-ends of the developed inverters. These include three-phase single-switch (3P1SW) SMR, three-phase bridgeless SMR and three-phase single-switch zero-current-transition (3P1SW ZCT) SMR. The established different SMR-fed inverter systems are assessed their performances comparatively by measured results.
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Yang, Shu-Wei, and 楊書瑋. "The Implementation of a Reduced-switch Three-Phase Multilevel Inverter by SVPWM Technology." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/54977151234211787852.
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碩士<br>國立高雄應用科技大學<br>電機工程系博碩士班<br>102<br>The thesis investigates the application of the space vector pulse width modulation (SVPWM) to a three phase multilevel inverter(MLI) with fewer switches. The principle of the three phase multilevel inverter and SVPWM is analyzed in detail and the MATLAB/Simulink is used for simulation. The proposed inverter uses only nine power switches and its usage of the power switches is 25% reduction as compared with the same level NPC inverter.
In comparison with the conventional sine pulse width modulation method (SPWM), the proposed SVPWM is more suitable for digitization and has higher voltage utilization, and a smaller total harmonic distortion. Finally, a three-phase multi-level inverter with the reduce switches is implemented by a micro-controller and CPLD. The experimental results show the feasibility of the proposed converter.
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Lin, Cheng-Tsung. "Speed Sensorless Control for Four-Switch Three-Phase Brushless DC Motor." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2707200701541500.
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Lin, Cheng-Tsung, and 林正宗. "Speed Sensorless Control for Four-Switch Three-Phase Brushless DC Motor." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/41289516626194726741.
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博士<br>臺灣大學<br>電機工程學研究所<br>95<br>This dissertation proposes a novel asymmetric pulse width modulation (PWM) scheme for four-switch three-phase (FSTP) brushless dc (BLDC) motor drives. This PWM scheme not only achieves the BLDC motor using FSTP inverter, but also does not need any current sensor and complex algorithm, so it can make the lowest manufacture cost of the inverter. Furthermore, this dissertation proposes a novel commutation control for the FSTP BLDC motor drive without position sensor. This sensorless control detects the crossing point of two floating voltages, and estimates the commutation timing. This sensorless control only needs two voltage sensors, so it not only reduces the cost of position sensors, but also increases the reliability of whole system.
When the BLDC motor drive uses Hall sensors as position sensors, sampling rates of the rotor speed will change with the rotor speed of BLDC motors. The fuzzy PI controller presented in this dissertation includes three fuzzy logics and three PI controllers. When the speed of BLDC motors changes, fuzzy logics will give PI controllers suitable speed errors to achieve robust control. The fuzzy logic of the fuzzy PI controller presented in this dissertation is based on the rotor speed, and therefore the controller reduces the complex of fuzzy logics and is easy to be implemented.
Finally, we implement our novel asymmetric PWM scheme and novel sensorless control in DSP (Digital Signal Processor) which is designed by Texas Instruments, TI, incorporated and FPGA (Field Programmable Gate Array) which is designed by Xilinx to prove that the sensorless control does not need complex calculation, and can be implemented in very low cost controller.
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Lee, Yueh-Pao, and 李月寶. "Constant Frequency Hysteresis Current Controller for a Three-Phase Four-Switch Rectifier." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/53867856575848114266.
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碩士<br>國立清華大學<br>電機工程學系<br>91<br>Recently, due to the rapid progress in high technology industry, much better power quality is required to meet the need of highly accurate automation machinery. As a result, how to eliminate the harmonics to achieve high power quality in a rectifier has been discussed in many literatures. Owing to the fast response, easy implementation and with fixed bounded errors, the hysteresis current controller has been widely used in various applications. However, the variable switching frequency has rendered the increasing switching loss and the harder design of the filter. Hence, how to achieve fixed switching frequency control is one of the hot topics in the literature. In fact, it is the main object of this thesis to propose a novel control strategy of constant switching frequency hysteresis current controller.
First at all, the operation principle of the traditional hysteresis current controller and the corresponding controllable condition under different output DC voltages are introduced. The inequality constraint of the controllability is obtained through the derived model. Second, the closed form expression of switch turn-on time and the corresponding partition into proper sequence are obtained to achieve constant switching frequency and with fixed error bound at the same time. Third, by modifying the formula derived before, the error due to transient and nonideal switch characteristics can be corrected at the same time while calculating the turn-on time. By this way, one can not only avoid the accumulation of the error but also can reduce unnecessary computing time for additional error correction. Fourth, the control strategy is further refined to reduce half of the computing time and make the current error distribution more uniformly inside the error bound. Hence, one can achieve a better performance without increasing the switching frequency. Finally, a prototype is constructed and some experimental results are presented for verifying the feasibility of the proposed controller.
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Chen, Jhih-han, and 陳志翰. "Pulse Amplitude Modualtion control for Four Switch Three Phase Brushless DC Motor." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/30600638104908883968.
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碩士<br>雲林科技大學<br>電機工程系碩士班<br>98<br>A pulse amplitude modulation (PAM) scheme for four-switch three-phase (FSTP) Brushless dc (BLDC) motor driver is proposed. In this research, the system structure is based on the fly-back circuit and PAM FSTP BLDC motor driver. The fly-back circuit is used to provide the variable DC-bus voltage of the pulse-amplitude modulation driver, and also power factor correction.
In the FSTP structure, the dc-bus voltage of six phases is non-uniform, the FSTP structure is proposed. The new FSTP structure is added the extra two switches and two capacitors to implement the new circuit. The two capacitors are used to create the half dc-link voltage, and then the two switches are utilized to switch the half dc-link voltage and the DC-link voltage.
This thesis utilizes Matlab/simulink to create the model of system structure and simulate the results to confirm the possibility, based on the simulation results to design the controller of this system, and then implement the control system hardware in the FPGA development board. And experimental results are provided to show this structure is workable.
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Lee, Chaoching, and 李昭慶. "Design and Implementation of Three-Phase Four-Wire Inverter with Load Impedance Estimation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/09424151021618031902.
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碩士<br>國立中正大學<br>電機工程研究所<br>100<br>This thesis presents design and implementation of a three-phase four-wire inverter with load impedance estimation. The inverter can fulfill both grid-connected and stand-alone mode operations. In the stand-alone mode, the inverter with a neutral leg can generate sinusoidal output voltage for unbalanced load and nonlinear load. With the load impedance estimation, the controller can track the sinusoidal reference voltage accurately, and the inverter is allowed to have a wide inductance variation, reducing core loss and size significantly. The control law is derived based on the two-phase modulation (TPM) scheme with a dead-beat control and on-line load impedance estimation, in which the repetitive control concept is adopted to reduce the estimation tolerance. Computer simulation and experimental results from a 10 kVA three-phase four-wire inverter have been presented to confirm the feasibility of the inverter.
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Wang, Tzu-Chien, and 王子健. "Speed Control of Four-Switch Three-Phase Brushless DC Motor without Position Sensors." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/55048584178763861139.
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碩士<br>國立臺灣大學<br>電機工程學研究所<br>96<br>This thesis proves the practicability of the low cost structure using a four-switch three-phase inverter without position sensors, and proposes a novel fuzzy PI control theory. Besides theory computation, the thesis also presents complete experimental results in proof of the theory.
Decreasing the cost of the actuators is a tendency in the future. This thesis applies a novel asymmetric pulse width modulation (PWM) scheme and uses the structure of four-switch three-phase (FSTP) brushless dc (BLDC) motor drives to reduce the cost. This PWM scheme not only achieves the BLDC motor using FSTP inverter, but also does not require any current sensor and complex algorithm, so the lowest manufacture cost of the inverter could be achieved. First, this thesis applies a novel commutation control for the FSTP BLDC motor drive without using position sensors. This sensorless control detects the crossing point of two floating voltages, and estimates the appropriate commutation timing. It only requires two voltage sensors to reduce the cost of position sensors and increases the reliability of whole system. Furthermore, this technique reduces the numbers of power switches and doesn’t require any position sensor.
When the brushless dc motor runs with or without Hall sensors, the frequency of the position signals depends on the rotor speed. Considering this phenomenon, the fuzzy PI controller including three fuzzy logics and three PI controllers is designed in this thesis. If the speed of BLDC motor varies, the fuzzy PI controller will trigger the defined PI controllers depending on the rotor speed and sum the weighted output of each PI controllers. Then it delivers the command to the inverter in order to modulate the duty cycle. This kind of fuzzy PI controller provides higher flexibility of design, and a more robust goal is accomplished. The fuzzy logic of the fuzzy PI controller designed in this thesis is based on the rotor speed, and therefore the controller reduces the complex of fuzzy logics and is easy to be implemented. Finally, the whole algorithm is implemented in a DSP. This thesis focuses on distinct sampling methods, and the experimental results with distinct conditions are compared and discussed.
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Sun, Wei-You, and 孫瑋佑. "The Control and Implementation of Three-Phase Four-Leg DC-to-AC Power Inverter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38861606677135525723.
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碩士<br>清雲科技大學<br>電機工程研究所<br>96<br>Generally,the traditional three-phase three-leg DC-to-AC power inverter are used widely with three phase balanced loads. But, when the three-phase loads are unbalanced, that
three phase voltage outputs can not be symmetrical. In this paper presents a three-phase four-leg DC-to-AC power inverter can be supply a midpoint to three phase unbalanced loads.So the three-phase four-leg DC-to-AC power inverter outputs three phase symmetrical
voltages.
Using symmetrical model analysises three-phase four-leg DC-to-AC power inverter how it suppresses the unbalanced loads. The mathematic model of three-phase four-leg DC-to-AC power inverter is established in different coordinates. Paper accomplishes the
decoupling of the three-phase four-leg DC-to-AC power inverter. PI double loop controller based on synchronous frame is applied.
The control circuit cosists of digital processor(DSP TMS320F2808PZA),which programmed in C language. The performance of system is simulated MATLAB SIMULINK. Experiments the three-phase four-leg DC-to-AC power inverter can output three-phase balanced AC voltage under the unbalanced loads conditions.
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Lin, Kai-Zhen, and 林楷晸. "Design and Implementation of a Multi-function Three-phase Four-wire Half-bridge Bidirectional Inverter." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/5syh88.
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碩士<br>國立雲林科技大學<br>電機工程系<br>105<br>Due to the demand of power consumption is increasing, renewable energy technology is developed in every country. A three phase bidirectional structure is developed in this paper, which includes three modes: one is a grid connected inverter, another is a power factor corrector converter, and the last is an uninterruptible power system. Moreover, the paper also considers the situation when this system operates in grid connected mode but the sudden grid fault, the passive island detection method is developed to detect the island phenomenon. This method is able to discover grid fault and turn off the grid-connected output immediately.
The paper use bidirectional structure to reduce the circuit size and cost, and adopted Renesas Electronics' microcontroller RX62T for digital control. The MCU is used to detector the zero crossing point of grid and sense the voltage and current, then calculate and output the suitable switching control signals. Grid connected and power factor corrections are performed by the division-summation control method; Uninterruptible power system is implemented with sinusoidal pulse width modulation and a PI controller.
The operating principle of circuit, algorithm derivation, hardware and software are detailed in this paper. And, a 10kW three-phase four-wire half-bridge bidirectional inverter is implemented, the experimental results show the hardware and software design of this paper is workable.
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Hsu, Chih-Wei, and 許志偉. "Design and Implementation of A Three-Phase Four-Wire Multi-Function Inverter with LLCL Filter." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/40974787757513704336.
Full textAbstract:
碩士<br>國立清華大學<br>電機工程學系<br>104<br>This thesis presents design and implementation of a three-phase four-wire inverter with LLCL output filter. To achieve higher applicability in the emerging development of dc micro-grid and renewable energy systems, the inverter is equipped with multiple functions, including grid-connection, rectification, dc-link voltage regulation and active power filtering (APF).
In general, control strategies used in most multi-function systems tend to be complex, where each operation mode requires its own way of control. However, the division-summation (D-∑) digital control adopted in this thesis is able to overcome the above problem. With one common duty-ratio expression, various operations can be realized with different current commands, which greatly reduces the control complexity. Furthermore, with system parameters such as grid voltage, dc-link voltage, filter inductance and switching period included in the duty-ratio expression, the inverter is capable of operating normally despite of parameter variation.
Being the first to apply the D-∑ digital control to the inverter with an LLCL filter, this thesis also proposes several solutions on problems that could occur in hardware implementation; besides, parameter design procedure is also addressed and can be adapted to applications with different specifications.
Finally, each operation mode has been tested with a prototype built in lab. Measured results show consistency with simulation, and most importantly, output current can comply with the total harmonic distortion requirement stated in “IEEE Std 519™-2014”.
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Chiang, Tai-Chi, and 江泰祈. "Design of Power Flow Controllers Based on Two-Leg Four-Switch Three Phase Power Converter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26223247048890248097.
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碩士<br>國立聯合大學<br>電機工程學系碩士班<br>99<br>This thesis is focused on the design of low-cost high-performance power system controllers, in which static synchronous compensators (STATCOM) and static series synchronous compensators (SSSC) are two major design targets. The development of the proposed power flow controllers is mainly based on the hardware configuration of a 2-leg 4-switch (2L4S) three-phase inverter and issues regarding advantages and possible limitations in performing power flow regulation and voltage control functions are the main concerns. In this thesis, a number of switching techniques, e.g. voltage hysteresis, sinusoidal pulse width modulation and space vector pulse width modulation techniques are investigated. The concepts of P-Q axis control scheme and the conventional PI controllers are utilized in the proposed power flow controllers. The main control functions designed for the proposed hardware simplified compensators include the dynamic voltage control and P-Q regulations of power networks. To demonstrate the feasibility of the proposed controllers and verify their performances, a set of simulation cases on simplified power systems are constructed in the MATLAB/SIMULINK software environment and comprehensive simulation studies are carried out. Results obtained from various case studies verify the feasibility and effectiveness of the proposed 2L4S based power flow controllers.
Keywords: power system control, power flow controller, power converter, static synchronous compensator, static series synchronous compensators
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Huang, Hsu-Yun, and 黃勖昀. "Design and Implementation of Three-Phase Four-Wire Inverter with Load Impedance Estimation and Iterative-Learning Control." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/83173068641099534403.
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碩士<br>國立中正大學<br>電機工程研究所<br>101<br>This thesis presents design and implementation of a three-phase four-wire inverter with load impedance estimation and iterative-learning control. The inverter can operate at the grid-connected and stand-alone mode conditions. In the stand-alone mode, the inverter with a neutral leg can generate sinusoidal output voltage for unbalanced load and nonlinear load. With the load impedance estimation, the controller can track the sinusoidal reference voltage accurately, and the inverter has considered a wide inductance variation, reducing core size significantly. The control law is based on a two-phase modulation (TPM) scheme with a D-∑ digital control and on-line load impedance estimation. Additionally, the iterative-learning control concept is adopted to reduce total voltage harmonic distortions. Finally, the computer simulation and experimental results measurements are performed for a 10 kVA three-phase four-wire inverter to verify the feasibility of the inverter.
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Tseng, Chia-Hung, and 曾嘉宏. "A POSITION SENSORLESS SWITCHED-RELUCTANCE MOTOR DRIVE WITH THREE-PHASE FOUR-QUADRANT SWITCH-MODE RECTIFIER FRONT-END." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/72095486914013511974.
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碩士<br>國立清華大學<br>電機工程學系<br>101<br>This thesis is mainly concerned with the development of a switched-reluctance motor (SRM) drive equipped with a three-phase four-quadrant front-end switch-mode rectifier (SMR). First, an asymmetric bridge converter fed SRM drive is constructed using off-the-shelf power modules. Through properly designed current and speed control schemes, the established motor drive possesses good driving characteristics, including acceleration/deceleration, reversible and regenerative braking operations. Then the high-speed driving performance enhancement via commutation instant advanced shift and voltage boosting are explored experimentally.
Next, a three-phase four-quadrant SMR is established and employed as the front-end of SRM drive. It can draw the power from the mains with power factor correction and possess regenerative braking energy recovery capability. Moreover, the DC-link voltage of the SRM drive can also be adjustable and boostable for effectively enhancing the SRM driving performance under higher speeds. For completeness, the driving characteristics of the SRM drive powered by other two types of three-phase SMRs are comparatively evaluated.
In addition, a SRM position sensorless control scheme based on narrow pulse voltage injection is proposed. The voltage pulses with suited frequency and duration are injected into the demagnetized phase winding via the DSP PWM channel. The resulted winding currents are sensed and processed to yield an observed Hall signal and used for making the SRM position sensorless control. In sensorless control operation, the motor is initially started in stepping motor mode. As the speed rises to an appropriate value, the operation is changed to switched-reluctance motor mode using the observed Hall signal. And the speed feedback control is conducted using the observed speed, which is obtained from the sensed four winding currents.
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Lee, Po Hung, та 李柏宏. "Design and Implementation of a 20 kVA D-Σ Digital Controlled Three-Phase Four-Wire Multi-Function Inverter System". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/5s7543.
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碩士<br>國立清華大學<br>電機工程學系<br>103<br>This thesis presents design and implementation of a 20 kVA division-summation (D-Σ) digital controlled three-phase four-wire multi-function inverter system. The in-verter can be operated in grid-connected or stand-alone mode to act as a renewa-ble-energy ac power-supply system. In the stand-alone mode, the control of this in-verter uses the D-Σ digital control law for voltage tracking which includes load im-pedance estimation and repetitive control, causing the inverter can stabilize sinusoidal output voltage for unbalanced load and nonlinear load. For the grid-connected mode, in order to achieve a specific PF and stabilize grid voltage and frequency, the control is the D-Σ digital control law for current tracking which supplemented by a droop control based linear P-Q compensation. Moreover, the D-Σ digital control law in this research is based on Two-Phase Modulation (TPM) scheme and associated with the switching sequence transformed from space vector pulse width modulation (SVPWM) scheme, and thus, the inductance variation can be taken into account, reducing core size significantly. Finally, the control laws are verified with measured results from a 20 kVA three-phase four-wire inverter system.
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Ghoshal, Anirban. "Operation of Three Phase Four Wire Grid Connected VSI Under Non-Ideal Conditions." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3386.
Full textAbstract:
The necessity to incorporate renewable energy systems into existing electric power grid and need of efficient utilization of electrical energy are growing every day. A shunt connected Voltage Source Inverter(VSI) capable of bidirectional power flow and fast control has become one of the building block to address such requirements. However with growing number of grid connected VSI, new requirements related to harmonic injection, higher overall efficiency and better performances during short term grid disturbances have emerged as challenges. For this purpose a grid connected three phase four wire VSI with LCL filter can be considered as a general module to study different control approaches and system behavior under ideal and non-ideal grid conditions. This work focuses on achieving enhanced performance by analyzing effect of non-ideal conditions on system level and relating it to individual control blocks.
In this work a phase locked loop structure has been proposed which is capable of extracting positive sequence fundamental phase information under non-ideal grid conditions. It can also be used in a single phase system without any structural modification. The current control for the three phase four wire VSI system has been implemented using Proportional Resonant (PR) controller in a per phase basis in stationary reference frame. A simplified controller design procedure based on asymptotic representation of the system transfer function is proposed. Using this method expressions for controller gains can be derived. A common mode model of the inverter system has been derived for low frequencies. Using this model a controller is designed to mitigate DC bus imbalance caused by sensor and ADC channel offsets. A multi-rate approach for digital implementation of PR controller with low resource consumption, that is suitable for an FPGA like digital controller ,is proposed. This multi-rate method can maintain resonance frequency accuracy even at low sampling frequency and can easily be frequency adaptive. Anti-wind up methods for PI controller have been studied to find suitable anti-wind up methods for PR controller. The tracking anti-wind up method is shown to be suitable for use with a PR controller. The effectiveness of this method under sudden disconnection and reconnection of VSI from grid is experimentally verified. A resonant integrator based second order filter is shown to be useful for active damping of LCL filter resonance with a wide range of grid inductance variation. The proposed method utilizes the LCL filter capacitor voltage to estimate resonance frequency current. Suitability of fundamental current PR controller for active damping alone, and with the proposed method show the superiority of the proposed method especially for low switching frequencies.
Design oriented analysis of the above topics are included in the thesis. The theoretical understandings developed have been verified through experiments in the laboratory and can be readily implemented in industrial power electronic systems.
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Ghoshal, Anirban. "Operation of Three Phase Four Wire Grid Connected VSI Under Non-Ideal Conditions." Thesis, 2013. http://etd.iisc.ernet.in/2005/3386.
Full textAbstract:
The necessity to incorporate renewable energy systems into existing electric power grid and need of efficient utilization of electrical energy are growing every day. A shunt connected Voltage Source Inverter(VSI) capable of bidirectional power flow and fast control has become one of the building block to address such requirements. However with growing number of grid connected VSI, new requirements related to harmonic injection, higher overall efficiency and better performances during short term grid disturbances have emerged as challenges. For this purpose a grid connected three phase four wire VSI with LCL filter can be considered as a general module to study different control approaches and system behavior under ideal and non-ideal grid conditions. This work focuses on achieving enhanced performance by analyzing effect of non-ideal conditions on system level and relating it to individual control blocks.
In this work a phase locked loop structure has been proposed which is capable of extracting positive sequence fundamental phase information under non-ideal grid conditions. It can also be used in a single phase system without any structural modification. The current control for the three phase four wire VSI system has been implemented using Proportional Resonant (PR) controller in a per phase basis in stationary reference frame. A simplified controller design procedure based on asymptotic representation of the system transfer function is proposed. Using this method expressions for controller gains can be derived. A common mode model of the inverter system has been derived for low frequencies. Using this model a controller is designed to mitigate DC bus imbalance caused by sensor and ADC channel offsets. A multi-rate approach for digital implementation of PR controller with low resource consumption, that is suitable for an FPGA like digital controller ,is proposed. This multi-rate method can maintain resonance frequency accuracy even at low sampling frequency and can easily be frequency adaptive. Anti-wind up methods for PI controller have been studied to find suitable anti-wind up methods for PR controller. The tracking anti-wind up method is shown to be suitable for use with a PR controller. The effectiveness of this method under sudden disconnection and reconnection of VSI from grid is experimentally verified. A resonant integrator based second order filter is shown to be useful for active damping of LCL filter resonance with a wide range of grid inductance variation. The proposed method utilizes the LCL filter capacitor voltage to estimate resonance frequency current. Suitability of fundamental current PR controller for active damping alone, and with the proposed method show the superiority of the proposed method especially for low switching frequencies.
Design oriented analysis of the above topics are included in the thesis. The theoretical understandings developed have been verified through experiments in the laboratory and can be readily implemented in industrial power electronic systems.
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Wang, Jyun-Ting, and 汪俊廷. "Design and Implementation of Regulated Dual-Voltage-Vector Predictive Current Controllers for Three-Phase Four-Switch Synchronous Reluctance Motor Drive Systems." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/he8u64.
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碩士<br>國立臺灣海洋大學<br>電機工程學系<br>107<br>This thesis proposes regulated dual-voltage-vector predictive current controllers for three-phase four-switch inverter synchronous reluctance motor drive systems. First of all, the motor drive control system has always been an indispensable part of the industry. The cost of reducing the motor drive is a constant trend. The three-phase four-switch drive system can effectively reduce the hardware development cost compared with the six-switch drive systems. However, there is a voltage imbalance problem, which seriously affects the control current control performance. This thesis proposes a model-free predictive current control. This method is based on the detection of motor current, indicating that this method is not affected by motor parameters and voltage imbalance.
Secondly, the switch combinations that can be selected in the three-phase four-switch drive system are limited. Unlike predictive current control using four voltage vectors, the proposed method uses eight resultant voltage vectors, each of which is composed of two voltage vectors. Since the number of switch combinations that can be selected is increased, the current error is effectively reduced.
Finally, in order to verify the feasibility and correctness, the system architecture is simulated by Matlab®(R2017a)/Simulink. The implementation is based on the TMS320F28379D digital signal processor produced by Texas Instruments as the core of the control, providing 17 sets of experimental results. It is further desirable to meet the need for low-cost drive systems equipped with high-performance current control.