Academic literature on the topic 'Line Commutated Inverter (LCI)'
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Journal articles on the topic "Line Commutated Inverter (LCI)"
1
Li, Huan, and Kang Qin. "Dynamic Phasor Modelling of LCC-HVDC System Based on a Practical Project." E3S Web of Conferences 256 (2021): 01034. http://dx.doi.org/10.1051/e3sconf/202125601034.
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This paper presents a detailed dynamic phasor modeling process of a line-commutated converter-based HVDC (LCC-HVDC) system. Firstly, the dynamic phasor models of the single-ended LCC rectifier station, inverter station and the DC line are established, respectively. Secondly, LCC-HVDC is an AC-DC-AC system. The interfaces are explained to connect the converter stations with the DC line. Through block modeling, it is helpful to simplify the process and verify the accuracy of each block. Finally, based on a practical project, the model is compared with the electromagnetic-transient (EMT) simulation results in PSCAD/EMTDC to verify the accuracy of the dynamic phasor model.
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Li, Huan, and Kang Qin. "Influence of Inverter Controller Parameters on the Small-signal Stability of LCC-HVDC System Based on a Practical Project." E3S Web of Conferences 256 (2021): 01031. http://dx.doi.org/10.1051/e3sconf/202125601031.
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Unreasonable control parameters of the Line Commutated Converter based High Voltage Direct Current (LCC-HVDC) system may induce small-signal instability. This paper studies the impact of inverter controller parameters on steady response of the LCC-HVDC system under weak AC grid condition. Firstly, according to a practical project, the small-signal model of LCC-HVDC system is established based on the switching function. Then, the eigen-analysis method is adopted to study the impact of the controller parameters on the inverter side on the oscillation mode and damping characteristics of the LCC system, and the correctness of results is verified by PSCAD/EMTDC simulation. The conclusion shows that reasonable controller parameters can improve the stability margin of the system.
3
T., Suhasini, and Mohana Rekha M. "Analysis and Control of Grid Connected DFIG Under Sub and Super Synchronous Modes of Operation." International Journal of Trend in Scientific Research and Development 2, no. 2 (2018): 1009–17. https://doi.org/10.31142/ijtsrd9568.
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The most reliable system in the present scenario for effective use of the wind power is grid integrated Doubly Fed Induction Generator DFIG . The implementation of a simple power converter arrangement in the rotor circuit for variable speeds has been proposed. Depending on wind speed, a DFIG based variable speed wind turbine is capable of operating in sub synchronous or super synchronous mode of operation using power electronic converters. The power flow in the rotor circuit is controlled for controlling the stator power in both the modes of operation by effecting rotor voltage through IGBT in sub synchronous mode whereas in super synchronous mode it is controlled by current sequence through LCI. The complete system has been modeled Using MATLAB SIMULINK blocks and simulation study has been conducted, the operation of the proposed scheme is illustrated at different operating conditions i.e. above and below synchronous speeds. T. Suhasini | M. Mohana Rekha "Analysis and Control of Grid Connected DFIG Under Sub & Super Synchronous Modes of Operation" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-2 , February 2018, URL: https://www.ijtsrd.com/papers/ijtsrd9568.pdf
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Zhang, Wei, and Dong Wang. "S-Transform Based Traveling Wave Directional Pilot Protection for Hybrid LCC-MMC-HVDC Transmission Line." Energies 15, no. 13 (2022): 4802. http://dx.doi.org/10.3390/en15134802.
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In this paper, the traveling wave protection issue of a hybrid high-voltage direct-current transmission line based on the line-commutated converter and modular multilevel converter is investigated. Generally, traveling wave protection based on voltage variation criterion, voltage variation rate criterion and current variation rate criterion is applied on hybrid high-voltage direct-current transmission lines as primary protection. There are two issues that should be addressed: (i) it has no fault direction identification capability which may cause wrong operation regarding external faults; and (ii) it does not consider the difference between line-commutated converter based rectifier station topology and modular multilevel converter based inverter station topology. Therefore, a novel traveling wave directional pilot protection principle for the hybrid high-voltage direct-current transmission line is proposed based on the S-transform. Firstly, the data processing capability of S-transform is described. Secondly, the typical traveling wave propagation process on a hybrid high-voltage direct-current transmission line is studied. Thirdly, a novel traveling wave fault direction identification principle is proposed. Eventually, based on PSCAD/EMTDC, a typical ±400 kV hybrid high-voltage direct-current transmission system is used for a case study to verify its robustness against fault location, fault resistance and fault type.
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Yao, Wei, Lingrao Wang, Yongxin Xiong, et al. "Interaction Mechanism and Coordinated Control of Commutation Failure Prevention in Multi-Infeed Ultra-HVDC System." International Transactions on Electrical Energy Systems 2022 (February 27, 2022): 1–18. http://dx.doi.org/10.1155/2022/7088114.
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Commutation failure (CF) is an inherent drawback of line-commutated converter high-voltage DC (LCC-HVDC) system. And CF prevention (CFPREV) control is widely applied in UHVDC lines to mitigate the subsequent CF. However, the formation of a multi-infeed UHVDC system induces power exchange and voltage interaction between AC buses during the transient process, making the behaviors and mitigation of CFs more complex. Consequently, exploring the impact of CFPREV control on adjacent stations and optimizing the CFPREV control to adapt to the interaction characteristics in a multi-infeed system is necessary. Considering the interaction characteristics, the impact of CFPREV control on the commutation process of inverters in a multi-infeed system is analyzed through formula derivation and simulation verification. It is found that although CFPREV control can effectively mitigate the CFs of the inverter near the fault, it will further increase the risk of concurrent CF (CCF) of remote inverters due to the interaction on the AC side. To solve this problem, a coordinated control scheme of CFPREV controls in a multi-infeed UHVDC system is proposed. The output of the CFPREV control of the inverter near the fault can be adjusted adaptively according to the commutation margins of remote inverters. And the probability of CCF caused by CFPREV control is consequently decreased. Case studies are conducted based on Henan provincial multi-infeed UHVDC system in China to verify the analysis result and the effectiveness of the coordinated control scheme of CFPREV controls.
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Feng, Qian, Ping Zeng, Desheng Zhou, Zhixin Du, Shaodong Guo, and Xiu Yang. "Research on continuous commutation failure suppression strategy for multi-feed DC transmission system considering harmonic characteristic factors." Journal of Physics: Conference Series 2797, no. 1 (2024): 012011. http://dx.doi.org/10.1088/1742-6596/2797/1/012011.
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Abstract Regarding the sustained issues of commutation failures in the hybrid double-fed DC system encompassing Line Commutated Converter High Voltage Direct Current (LCC-HVDC) and Modular Multilevel Converter High Voltage Direct Current (MMC-HVDC, from the perspective of harmonics, the harmonics in the voltage waveform of the AC bus on the inverter side are analyzed. Besides, a commutation failure suppression strategy for the hybrid doubly-fed DC transmission system based on the minimum shutdown area is designed, in which the setting value of the shutdown angle of the harmonic is considered in the minimum shutdown area. The reactive power is obtained by attaching the setting value to the reactive power control link of MMC-HVDC, and the simulation analysis in PSCAD verifies that the strategy can make the MMC-HVDC output more reactive power during the fault in the weak AC system. Increasing the shut-off margin of the manifold reduces the potential for continuous commutation failures in LCC-HVDC.
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Zhou, Yi, Hongmei Luo, Hao Xu, et al. "Coordinated DC voltage control strategy for the receiving end hybrid LCC-VSC system." Journal of Physics: Conference Series 2728, no. 1 (2024): 012058. http://dx.doi.org/10.1088/1742-6596/2728/1/012058.
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Abstract The receiving end hybrid line commutated converter (LCC) — voltage source converter (VSC) system has the obstacle that when an AC fault occurs at the sending LCC side, the DC voltage of the rectifier side will fall, resulting in the power transmission reduction of the whole system. Particularly, when the rectifier side DC voltage falls below the inverter side DC voltage, the power transmission is interrupted, posing a huge threat to the stability of the power grid at both the sending and receiving ends. To tackle these problems, a coordinated DC voltage control strategy for the receiving end is proposed. By controlling the DC voltage of the receiving VSC, the proposed method can improve the DC system power transmission capability when voltage drops at the sending side. The proposed control strategy is simple but practical, which is good for the stable and secure operation of both the sending and the receiving power system.
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Wang, Ting, Kun Chen, Long’en Zhang, Xingyang Hu, Hengxuan Li, and Pangqi Ye. "Research on Fault Identification of Hybrid Multi-Feed High-Voltage Direct Current System Based on Line Commutated Converter and Voltage Source Converter." Energies 17, no. 9 (2024): 2215. http://dx.doi.org/10.3390/en17092215.
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With the rapid development of voltage source converter (VSC) and line commutated converter (LCC) technology and the relative concentration of power and load, the inverter station of the flexible DC system is fed into the same AC bus with the conventional DC rectifier station, and the high-voltage direct current (HVDC) parallel hybrid feed system is formed in structure. As the electrical distance between the converter stations is very close, when a fault occurs in the near area, the current on the AC wiring on the VSC side will fluctuate greatly, resulting in the misoperation of the AC wiring protection. For this reason, this paper proposes a fault identification method based on VSC/LCC hybrid multi-fed HVDC system, which discriminates the fault and outputs the protection signal according to the protection criterion, and logically judges the combination of the output protection signal to identify the fault type. The simulation results show that the method can identify all kinds of faults of hybrid multi-feed DC system and solve the problem of protection misoperation of the hybrid multi-feed DC system.
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Wang, Hua, Ao Zheng, Ziwen Liu, Wei Liu, Xueqing Pan, and Chunsun Tian. "A Suppression Method of Commutation Failure in LCC-UHVDC Systems Based on the Dynamic Tracking of the Turn-Off Angle Setting Value." Electronics 13, no. 7 (2024): 1353. http://dx.doi.org/10.3390/electronics13071353.
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Commutation failure is still one of the most common faults in LCC-UHVDC (line commutated converter-based, ultra-high voltage direct current) systems, and if the inverter side, extinction angle, and rectification value remain constant during the fault, it may lead to commutation failure or even continuous commutation failure. Therefore, this paper first analyzes the structure of the LCC-UHVDC system and the mechanism of commutation failure and, on this basis, proposes a commutation failure suppression method based on dynamic tracking of the extinction angle rectification value. The desired DC voltage of the system under fault conditions is calculated based on key state quantities such as the AC voltage RMS value, the extinction angle, and the leading angle during the fault process. The compensation amount is obtained by comparing the desired DC voltage with the actual DC voltage and superimposition on the extinction angle rectification value in the inverter extinction angle control. When there is a risk of commutation failure, dynamically adjusting the extinction angle setting value according to the compensation value is beneficial for the rapid and stable recovery of the extinction angle, reducing the probability of commutation failure. A bipolar neutral ground LCC-UHVDC testing model system is established in PSCAD/EMTDC for simulation verification to show that the proposed improved control strategy effectively reduces the probability of commutation failure and significantly improves the stable operation characteristics of the LCC-UHVDC system.
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Chen, Xiaolong, Xiaoqing Qi, Yongli Li, Bin Li, and Botong Li. "A Calculation Method of DC Current Reference Value for Suppressing Commutation Failure in LCC-HVDC System." Journal of Physics: Conference Series 2301, no. 1 (2022): 012024. http://dx.doi.org/10.1088/1742-6596/2301/1/012024.
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Abstract Line commutated converter based high voltage direct current (LCC-HVDC) transmission system is prone to suffer commutation failure, which can lead to the increase of DC current and the interruption of DC transmission power. Furthermore, the increase of DC current might lead to subsequent commutation failure. Based on the reactive power balance of the inverter AC bus, this paper studies the functional relationship between DC current and commutation voltage. The DC current reference value is obtained by using the DC current acquired from the above functional relationship, and combining with the DC current order given by voltage dependent current order limiter (VDCOL). This calculation method can adjust the DC current reference value in time according to the commutation voltage, thus limiting the increase of DC current. In order to verify the commutation failure suppression ability of the proposed method, several simulations are conducted based on CIGRE benchmark HVDC model in PSCAD/EMTDC. Simulation results show that the proposed method can not only suppress commutation failure successfully, but also improve the fault recovery performance of the LCC-HVDC system.
Dissertations / Theses on the topic "Line Commutated Inverter (LCI)"
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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.
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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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Jain, Amit Kumar. "Control Of High Power Wound Field Synchronous Motor Drives - Modelling Of Salient Pole Machine, Field Oriented Control Using VSI, LCI And Hybrid LCI/VSI Converters." Thesis, 2010. https://etd.iisc.ac.in/handle/2005/1985.
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This thesis proposes control schemes and converter configurations for high power wound field synchronous motor (WFSM) drives. The model for a salient pole WFSM in any general rotating reference frame is developed which can be used to derive models along known rotor (dq) and stator flux (MT) reference frames. Based on these models, the principle of sensor-less stator flux oriented field-oriented control (FOC) for salient pole WFSM is developed. So far in the literature, control of cylindrical rotor machine only has been addressed and the effects of saliency have generally been neglected. The performance of the proposed sensor-less FOC has been demonstrated by experimentally operating a 15.8 HP salient pole WFSM using a three-level IGBT based voltage source inverter (VSI).
The principle of FOC has been later extended to the control of current source load
commutated inverter (LCI) fed salient pole WFSM drives, where the drawbacks present in conventional self-control method such as rigorous off-line calculation for generation of look up tables, coupling between flux and torque control etc. are eliminated.
This thesis also proposes the combination of a VSI with the LCI power circuit to overcome the different disadvantages that are present in the existing LCI topology. Firstly, a novel starting scheme is proposed, where the LCI fed WFSM is started with the aid of a low power auxiliary VSI converter in a smooth manner with sinusoidal motor currents and voltages. This overcomes the difficulties of the present complex dc link current pulsing technique that has drawbacks such as pulsating torque, long starting time etc. In a second mode of operation, it is shown that the VSI can be connected to the existing LCI fed WFSM drive as a harmonic compensator in On-The-Fly mode; this will make the terminal stator current and voltage sinusoidal apart from cancellation of torque pulsations thus improving the drive performance. The above two schemes have potential as retrofit for existing drives.
It is possible to combine both the advantages, mentioned above, by permanently connecting the VSI with the LCI power circuit to feed the WFSM. This proposed hybrid LCI/VSI drive can be regarded as a universal solution for high power synchronous motor drives at all power and speed ranges.
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Jain, Amit Kumar. "Control Of High Power Wound Field Synchronous Motor Drives - Modelling Of Salient Pole Machine, Field Oriented Control Using VSI, LCI And Hybrid LCI/VSI Converters." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/1985.
Full textAbstract:
This thesis proposes control schemes and converter configurations for high power wound field synchronous motor (WFSM) drives. The model for a salient pole WFSM in any general rotating reference frame is developed which can be used to derive models along known rotor (dq) and stator flux (MT) reference frames. Based on these models, the principle of sensor-less stator flux oriented field-oriented control (FOC) for salient pole WFSM is developed. So far in the literature, control of cylindrical rotor machine only has been addressed and the effects of saliency have generally been neglected. The performance of the proposed sensor-less FOC has been demonstrated by experimentally operating a 15.8 HP salient pole WFSM using a three-level IGBT based voltage source inverter (VSI).
The principle of FOC has been later extended to the control of current source load
commutated inverter (LCI) fed salient pole WFSM drives, where the drawbacks present in conventional self-control method such as rigorous off-line calculation for generation of look up tables, coupling between flux and torque control etc. are eliminated.
This thesis also proposes the combination of a VSI with the LCI power circuit to overcome the different disadvantages that are present in the existing LCI topology. Firstly, a novel starting scheme is proposed, where the LCI fed WFSM is started with the aid of a low power auxiliary VSI converter in a smooth manner with sinusoidal motor currents and voltages. This overcomes the difficulties of the present complex dc link current pulsing technique that has drawbacks such as pulsating torque, long starting time etc. In a second mode of operation, it is shown that the VSI can be connected to the existing LCI fed WFSM drive as a harmonic compensator in On-The-Fly mode; this will make the terminal stator current and voltage sinusoidal apart from cancellation of torque pulsations thus improving the drive performance. The above two schemes have potential as retrofit for existing drives.
It is possible to combine both the advantages, mentioned above, by permanently connecting the VSI with the LCI power circuit to feed the WFSM. This proposed hybrid LCI/VSI drive can be regarded as a universal solution for high power synchronous motor drives at all power and speed ranges.
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Banerjee, Debmalya. "Load Commutated SCR Current Source Inverter Fed Induction Motor Drive With Sinusoidal Motor Voltage And Current." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/744.
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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.
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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.
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Hatua, Kamalesh. "Active Reactive Induction Motor - A New Solution For Load Commutated SCR-CSI Based High Power Drives." Thesis, 2010. https://etd.iisc.ac.in/handle/2005/2009.
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This thesis deals with a new solution for medium voltage drives. Load Commutated Inverter (LCI) fed synchronous motor drive is a popular solution for high power drive applications. Though the induction machine is more rugged and cheaper compared to the synchronous machine, LCI fed induction motor drive solution is not available. The basic advantage of a synchronous machine over an induction machine is the fact that the synchronous machine can operate at leading power factor. Due to this property load commutation of SCR switches of the LCI is achievable for synchronous machine. On the contrary an induction machine always draws lagging power factor current; this makes it unsuitable as a drive motor for LCI technology. In this thesis a new LCI fed induction motor drive configuration is developed as an alternative for synchronous motor drives.
A new variant of six phase induction motor is proposed in this context. The machine is named as Active Reactive Induction Machine (ARIM). The ARIM contains two sets of three-phase windings with isolated neutral. Both the windings have a common axis. One winding carries the active power and can be wound for higher voltage (say 11kV). The other winding supplies the total reactive power of the machine and can be wound for lower voltage (say 2.2 kV). The rotor is a standard squirrel cage. High power induction machines usually demand lesser magnitude of reactive power compared to the total power rating of the machine ( 20% ). Therefore excitation winding has a smaller fraction of the total machine rating compared to the power winding.
A VSI with an LC filter supplies reactive power to the ARIM through the excitation winding and ensures leading power factor at the power winding. This is similar to the excitation control of the LCI fed synchronous machine. The direct VSI connection is possible due to the lower voltage rating for the excitation winding. In this way, the VSI voltage rating does not limit the highest motor voltage that can be handled. An LCI supplies the real power into the ARIM from the power winding. The LCI currents are quasi square wave in shape. Therefore they have rich low order harmonic content. They cause 6th and 12th harmonic torque pulsations in the machine. This is a problem for the LCI fed synchronous machine drive. In the proposed drive, the VSI can compensate these low frequency m.m.f. harmonics inside the machine air gap to remove torque pulsation and rotor harmonic losses. The advantage of the proposed topology is that no transformer is required to drive an 11kV machine.
It is always desirable to feed sinusoidal voltage and current to both the power winding and the excitation winding. To address this problem, a second configuration is proposed. A low power three-level VSI is connected in shunt at the power winding with the proposed ARIM drive as discussed above. This VSI compensates the low frequency harmonic currents to achieve sinusoidal motor currents at the motor winding. This VSI acts as a shunt active filter and compensates for the lower order harmonics injected by the LCI.
The proposed topologies have LC filters to maintain sinusoidal motor voltages and currents by absorbing the VSI switching frequency components. But the motor terminal voltage oscillates at system resonant frequency due to the presence of LC filters. These resonant components in the terminal voltages are required to be eliminated for smooth terminal voltages and safe load commutation of the thyristors. In this thesis a simple active damping method is proposed to mitigate these issues.
The proposed topologies are experimentally verified with an ARIM with 415 V power winding and 220 V excitation winding. The control is carried out on a digital platform having a TMS 320LF 2407A DSP processor and an ALTERA CYCLONE FPGA processor. Results from the prototype experimental drive are presented to show the feasibility and performance of the proposed drive configurations.
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Hatua, Kamalesh. "Active Reactive Induction Motor - A New Solution For Load Commutated SCR-CSI Based High Power Drives." Thesis, 2010. http://hdl.handle.net/2005/2009.
Full textAbstract:
This thesis deals with a new solution for medium voltage drives. Load Commutated Inverter (LCI) fed synchronous motor drive is a popular solution for high power drive applications. Though the induction machine is more rugged and cheaper compared to the synchronous machine, LCI fed induction motor drive solution is not available. The basic advantage of a synchronous machine over an induction machine is the fact that the synchronous machine can operate at leading power factor. Due to this property load commutation of SCR switches of the LCI is achievable for synchronous machine. On the contrary an induction machine always draws lagging power factor current; this makes it unsuitable as a drive motor for LCI technology. In this thesis a new LCI fed induction motor drive configuration is developed as an alternative for synchronous motor drives.
A new variant of six phase induction motor is proposed in this context. The machine is named as Active Reactive Induction Machine (ARIM). The ARIM contains two sets of three-phase windings with isolated neutral. Both the windings have a common axis. One winding carries the active power and can be wound for higher voltage (say 11kV). The other winding supplies the total reactive power of the machine and can be wound for lower voltage (say 2.2 kV). The rotor is a standard squirrel cage. High power induction machines usually demand lesser magnitude of reactive power compared to the total power rating of the machine ( 20% ). Therefore excitation winding has a smaller fraction of the total machine rating compared to the power winding.
A VSI with an LC filter supplies reactive power to the ARIM through the excitation winding and ensures leading power factor at the power winding. This is similar to the excitation control of the LCI fed synchronous machine. The direct VSI connection is possible due to the lower voltage rating for the excitation winding. In this way, the VSI voltage rating does not limit the highest motor voltage that can be handled. An LCI supplies the real power into the ARIM from the power winding. The LCI currents are quasi square wave in shape. Therefore they have rich low order harmonic content. They cause 6th and 12th harmonic torque pulsations in the machine. This is a problem for the LCI fed synchronous machine drive. In the proposed drive, the VSI can compensate these low frequency m.m.f. harmonics inside the machine air gap to remove torque pulsation and rotor harmonic losses. The advantage of the proposed topology is that no transformer is required to drive an 11kV machine.
It is always desirable to feed sinusoidal voltage and current to both the power winding and the excitation winding. To address this problem, a second configuration is proposed. A low power three-level VSI is connected in shunt at the power winding with the proposed ARIM drive as discussed above. This VSI compensates the low frequency harmonic currents to achieve sinusoidal motor currents at the motor winding. This VSI acts as a shunt active filter and compensates for the lower order harmonics injected by the LCI.
The proposed topologies have LC filters to maintain sinusoidal motor voltages and currents by absorbing the VSI switching frequency components. But the motor terminal voltage oscillates at system resonant frequency due to the presence of LC filters. These resonant components in the terminal voltages are required to be eliminated for smooth terminal voltages and safe load commutation of the thyristors. In this thesis a simple active damping method is proposed to mitigate these issues.
The proposed topologies are experimentally verified with an ARIM with 415 V power winding and 220 V excitation winding. The control is carried out on a digital platform having a TMS 320LF 2407A DSP processor and an ALTERA CYCLONE FPGA processor. Results from the prototype experimental drive are presented to show the feasibility and performance of the proposed drive configurations.
Conference papers on the topic "Line Commutated Inverter (LCI)"
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Shanthi, T., and N. Ammasai Gounden. "Power electronic interface for grid-connected PV array using boost converter and line-commutated inverter with MPPT." In 2007 International Conference on Intelligent and Advanced Systems (ICIAS). IEEE, 2007. http://dx.doi.org/10.1109/icias.2007.4658513.
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Sood, V. K. "Analysis and simulator evaluation of a dc line-side force-commutated HVDC inverter for feeding a remote load." In 1985 IEEE Power Electronics Specialists Conference. IEEE, 1985. http://dx.doi.org/10.1109/pesc.1985.7071001.
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Unlu, Murat, Sabri Camur, Ersoy Beser, and Birol Arifoglu. "A modified line-commutated inverter for grid-connected photovoltaic systems with voltage-based maximum power point tracking method." In 2017 International Symposium on Power Electronics (Ee). IEEE, 2017. http://dx.doi.org/10.1109/pee.2017.8171672.
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Lavanya, V., N. Ammasai Gounden, and Polimera Malleswara Rao. "A Simple Controller using Line Commutated Inverter with Maximum Power Tracking for Wind-Driven Grid-Connected Permanent Magnet Synchronous Generators." In 2006 International Conference on Power Electronic, Drives and Energy Systems. IEEE, 2006. http://dx.doi.org/10.1109/pedes.2006.344281.
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Zamani, A., and H. Shahalami. "Performance of a hybrid series filter in mitigating power quality problem of a grid-connected PV array interfaced with a line-commutated inverter." In 2014 22nd Iranian Conference on Electrical Engineering (ICEE). IEEE, 2014. http://dx.doi.org/10.1109/iraniancee.2014.6999616.
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Arjun, A., B. Vinod, N. Kumaresan, and D. R. Binu Ben Jose. "A power electronic controller for PV-tied Grid-connected system with single parameter sensing for mppt using boost converter and line-commutated inverter." In 2012 IEEE Third International Conference on Sustainable Energy Technologies (ICSET). IEEE, 2012. http://dx.doi.org/10.1109/icset.2012.6357372.
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Sihler, Christof, Simon Schramm, Valerio Rossi, Andrea Lenzi, and Valerio Depau. "Electronic Torsional Vibration Elimination for Synchronous Motor Driven Turbomachinery." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46005.
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The oil and gas industry has a growing demand for electrically driven trains operated at variable speeds. Variable frequency electrical drives enable increased operational flexibility and energy efficiency. One drawback of power electronics driven systems is the generation of non-fundamental air-gap torque ripple components due to electrical harmonics. The air-gap torque ripple can interact with the mechanical system at natural torsional frequencies of the drive train. Uncontrolled excited torsional vibration can silently lead to coupling failure due to fatigue. The coincidence of electrical drive harmonics and natural torsional frequencies of the mechanical system is sometimes unavoidable, due to the large variable speed range of the compressor as for process requirements. For those types of applications, a damping system utilizing available power electronics has been developed that can be applied to new units but also as a retrofit solution in existing variable speed trains. Electronic torsional vibration elimination (eTVe) is based on an angular vibration measurement in the mechanical system and an interface to the existing inverter control of the electrical drive. An important milestone of the eTVe development was achieved in 2010, in site testing this new solution to Liquid Natural Gas (LNG) production trains and demonstrating that it can completely eliminate torsional vibrations. With eTVe a residual torsional vibration level was achieved that was lower than the vibration level measured while the LNG train was only gas turbine driven. This torsional performance was achieved with a standard load commutated inverter drive (LCI). LCIs are one of the most widespread electrical drive technology for gas compression trains because of excellent reliability records, and it is the only one referenced solution for electric power larger than 45 MW.
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Corliss, James M., and H. Sprysl. "Measured Torsional Vibration Characteristics of a 100 Megawatt Wind Tunnel Drive Line." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/vib-8276.
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Abstract A new 100 MW (135,000 Hp) adjustable speed drive system has recently been installed in the NASA Langley National Transonic Facility. The 100 MW system is the largest of its kind in the world and consists of a salient pole synchronous motor powered by a 12-pulse Load Commutated Inverter variable frequency drive. During system commissioning the drive line torsional vibrations were measured with strain gages and a telemetry-based data acquisition system. The torque measurements included drive start-up and steady-state operation at speeds where the drive motor’s pulsating torques match the drive line’s torsional natural frequency. Rapid drive acceleration rates with short dwell times were effective in reducing torsional vibrations during drive starts. Measured peak torsional vibrations during steady-state operation were comparable to predicted values and large enough to produce noticeable lateral vibrations in the drive line shafting. Cyclic shaft stresses for all operating conditions were well within the fatigue limits of the drive line components. A comparison of the torque measurements to an analytical forced response model concluded that a 0.5% critical damping ratio was appropriately applied in the drive line’s torsional analysis.