Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6259242
Wang Gao-lin, Wu Fang, L. Gang, G. Qiang, X. Dianguo
This paper studies the sensorless interior permanent magnet synchronous motor (IPMSM) vector control strategy which is based on the EMF sliding-mode observer. As parameters selected for the position observer are obtained mostly by experimental adjustment, a phase locked loop (PLL) parameters design method based on the expected position estimation error is present. To improve the operation efficiency, a maximum torque per ampere (MTPA) control strategy based on current vector angle online tuning is introduced. In this way, the robustness against the motor parameters variations can be enhanced. The main idea is changing the reference of the stator current vector angle by a small value change, and then comparing the corresponding current value to tracking the ideal MTPA trajectory. The experiments on a 2.2kW IPMSM sensorless vector control system verifies the effectiveness of the PLL parameter design method and the MTPA control strategy.
{"title":"EMF-based position sensorless control of IPMSM with improved current vector control strategy","authors":"Wang Gao-lin, Wu Fang, L. Gang, G. Qiang, X. Dianguo","doi":"10.1109/IPEMC.2012.6259242","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6259242","url":null,"abstract":"This paper studies the sensorless interior permanent magnet synchronous motor (IPMSM) vector control strategy which is based on the EMF sliding-mode observer. As parameters selected for the position observer are obtained mostly by experimental adjustment, a phase locked loop (PLL) parameters design method based on the expected position estimation error is present. To improve the operation efficiency, a maximum torque per ampere (MTPA) control strategy based on current vector angle online tuning is introduced. In this way, the robustness against the motor parameters variations can be enhanced. The main idea is changing the reference of the stator current vector angle by a small value change, and then comparing the corresponding current value to tracking the ideal MTPA trajectory. The experiments on a 2.2kW IPMSM sensorless vector control system verifies the effectiveness of the PLL parameter design method and the MTPA control strategy.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115325197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6258995
K. Qu, Jinbin Zhao, Yuehong Xing
A Low-voltage ride-through (LVRT) control strategy is presented with full-power converter for direct-drive permanent magnet synchronous generator (PMSG) wind-power system. According to the LVRT requirements, control strategy is realized by limit the rise of DC-link voltage on basis of power balance between wind power side and grid side. Simulation results verify the effectiveness of the proposed method that the LVRT is achieved, power balanced and response quickly traced.
{"title":"A LVRT control strategy based on DC-link voltage limit for PMSG wind generation system","authors":"K. Qu, Jinbin Zhao, Yuehong Xing","doi":"10.1109/IPEMC.2012.6258995","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6258995","url":null,"abstract":"A Low-voltage ride-through (LVRT) control strategy is presented with full-power converter for direct-drive permanent magnet synchronous generator (PMSG) wind-power system. According to the LVRT requirements, control strategy is realized by limit the rise of DC-link voltage on basis of power balance between wind power side and grid side. Simulation results verify the effectiveness of the proposed method that the LVRT is achieved, power balanced and response quickly traced.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115373402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6258891
Liu Fangcheng, Liu Jinjun, Zhang Bin, Zhang Hao-dong, H. S. Ul
The renewable energy has become the research focus in recent years with the environment-friendly characteristic. Integrating energy storage system to the renewable energy system can enhance the stability and reliability of the whole power system. As one of the core technologies, energy management of the hybrid energy storage system attracts more and more attention. Hybrid energy storage system can improve the performance of the storage device with the battery as the main power source and the super capacitor as the auxiliary power source. This paper presents a control strategy based on the DC voltage regulation via sliding mode control that changes the working conditions of battery and super capacitor. When the supercapacitor voltage stays in the working range as designed, it will work as the auxiliary power source to maintain the DC voltage. When the supercapacitor voltage reaches the upper limit or the lower limit, the battery will be controlled to maintain the DC bus voltage, making the super capacitor voltage remain in a proper range. The simulation model is established in MATLAB and simulation results verify the validity of the proposed control method.
{"title":"Energy management of hybrid energy storage system (HESS) based on sliding mode control","authors":"Liu Fangcheng, Liu Jinjun, Zhang Bin, Zhang Hao-dong, H. S. Ul","doi":"10.1109/IPEMC.2012.6258891","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6258891","url":null,"abstract":"The renewable energy has become the research focus in recent years with the environment-friendly characteristic. Integrating energy storage system to the renewable energy system can enhance the stability and reliability of the whole power system. As one of the core technologies, energy management of the hybrid energy storage system attracts more and more attention. Hybrid energy storage system can improve the performance of the storage device with the battery as the main power source and the super capacitor as the auxiliary power source. This paper presents a control strategy based on the DC voltage regulation via sliding mode control that changes the working conditions of battery and super capacitor. When the supercapacitor voltage stays in the working range as designed, it will work as the auxiliary power source to maintain the DC voltage. When the supercapacitor voltage reaches the upper limit or the lower limit, the battery will be controlled to maintain the DC bus voltage, making the super capacitor voltage remain in a proper range. The simulation model is established in MATLAB and simulation results verify the validity of the proposed control method.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115587614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6258814
Byeong-Heon Kim, S. Sul, C. Lim
This paper presents an active Anti-Islanding Detection (AID) method using Negative Sequence Voltage (NSV) injection to electrical grid through a three-phase photovoltaic (PV) inverters. Because islanding operation mode can cause a variety of problems, the islanding detection of grid-connected PV inverter is the mandatory feature. The islanding mode is detected by measuring the magnitude of Negative Sequence Impedance (NSI) calculated by the negative sequence voltage and current at the point of common coupling (PCC). Simulation and experiment are performed to verify the effectiveness of the proposed method which can detect the islanding mode in the specified time. The test has been done in accordance with the condition on IEEE Std 929–2000.
{"title":"Anti-islanding detection method using Negative Sequence Voltage","authors":"Byeong-Heon Kim, S. Sul, C. Lim","doi":"10.1109/IPEMC.2012.6258814","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6258814","url":null,"abstract":"This paper presents an active Anti-Islanding Detection (AID) method using Negative Sequence Voltage (NSV) injection to electrical grid through a three-phase photovoltaic (PV) inverters. Because islanding operation mode can cause a variety of problems, the islanding detection of grid-connected PV inverter is the mandatory feature. The islanding mode is detected by measuring the magnitude of Negative Sequence Impedance (NSI) calculated by the negative sequence voltage and current at the point of common coupling (PCC). Simulation and experiment are performed to verify the effectiveness of the proposed method which can detect the islanding mode in the specified time. The test has been done in accordance with the condition on IEEE Std 929–2000.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"242 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115617773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6259187
Xianwen Bao, F. Zhuo, Baoquan Liu
This paper presents a method to design a control system for grid-connected Photovoltaic (PV) inverter which has a LCL-type filter to suppress the output current total harmonic distortion (THD). The conventional approach to design the control system is in synchronous reference domain, which transforms the ac variables into dc quantities and thus, possibility of applying the simple PI controller. However, in a LCL-type filter, the coupling terms are complicated due to the filter capacitance and inductance, and have not been formulated so far. It has been found that the major limitations of real and reactive power are the coupling terms. In this paper, the PV inverter adopts conventional double loops control strategy, inner inductance current control loop and outer DC link voltage control loop. An accurate linear model of three phase PV inverter is derived using feedback linearization method. The linearization system has successfully decoupled the real and reactive current loops and achieves desirable performance. A 250-kW three phase full bridge grid-connected inverter is presented to confirm the analytical results. Simulation results, using MATLAB/SIMULINK, presented for this strategy confirm the effectiveness of the control scheme.
{"title":"Feedback linearization control of photovoltaic inverter with LCL filter","authors":"Xianwen Bao, F. Zhuo, Baoquan Liu","doi":"10.1109/IPEMC.2012.6259187","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6259187","url":null,"abstract":"This paper presents a method to design a control system for grid-connected Photovoltaic (PV) inverter which has a LCL-type filter to suppress the output current total harmonic distortion (THD). The conventional approach to design the control system is in synchronous reference domain, which transforms the ac variables into dc quantities and thus, possibility of applying the simple PI controller. However, in a LCL-type filter, the coupling terms are complicated due to the filter capacitance and inductance, and have not been formulated so far. It has been found that the major limitations of real and reactive power are the coupling terms. In this paper, the PV inverter adopts conventional double loops control strategy, inner inductance current control loop and outer DC link voltage control loop. An accurate linear model of three phase PV inverter is derived using feedback linearization method. The linearization system has successfully decoupled the real and reactive current loops and achieves desirable performance. A 250-kW three phase full bridge grid-connected inverter is presented to confirm the analytical results. Simulation results, using MATLAB/SIMULINK, presented for this strategy confirm the effectiveness of the control scheme.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115716004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6259224
Yanping Xu, Yongbo Fan, Y. Zhong
Direct Torque Control (DTC) of Permanent Magnet Synchronous Motor (PMSM) has quick response and simple structure, but it has the disadvantages of large torque ripples and inconstant switching frequency. An improved DTC method of PMSM based on backstepping control is proposed in this paper. For direct torque control, speed, torque and flux linkage are selected as virtual state variables and then a backstepping controller is designed to produce reference stator voltage components. Then according to those voltage components, space vector modulation (SVM) is used to produce switching states of inverters. Simulation results show that the performance of the proposed DTC system has been dramatically improved. Compared to the traditional DTC, the proposed DTC based on backstepping control could effectively decrease flux and torque ripples, make inverters have constant switching frequency. Compared to the DTC based on PI control, the backstepping DTC has fewer adjusted parameters and has good dynamic performance and good robustness.
{"title":"An improved Direct Torque Control method of PMSM based on backstepping control","authors":"Yanping Xu, Yongbo Fan, Y. Zhong","doi":"10.1109/IPEMC.2012.6259224","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6259224","url":null,"abstract":"Direct Torque Control (DTC) of Permanent Magnet Synchronous Motor (PMSM) has quick response and simple structure, but it has the disadvantages of large torque ripples and inconstant switching frequency. An improved DTC method of PMSM based on backstepping control is proposed in this paper. For direct torque control, speed, torque and flux linkage are selected as virtual state variables and then a backstepping controller is designed to produce reference stator voltage components. Then according to those voltage components, space vector modulation (SVM) is used to produce switching states of inverters. Simulation results show that the performance of the proposed DTC system has been dramatically improved. Compared to the traditional DTC, the proposed DTC based on backstepping control could effectively decrease flux and torque ripples, make inverters have constant switching frequency. Compared to the DTC based on PI control, the backstepping DTC has fewer adjusted parameters and has good dynamic performance and good robustness.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115887028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6258864
M. S. Reza, M. Ciobotaru, V. Agelidis
This paper proposes the application of second order generalized integrator (SOGI) and Kalman filter (KF) technique for the rejection of DC offset and harmonics from the distorted grid voltage waveform. The SOGI is used to estimate the orthogonal waveforms of grid voltage fundamental frequency component. On the other hand, the linear Kalman filter (LKF) is used to reject the DC offset and harmonics present in the distorted grid voltage waveform. The resonance and harmonic frequencies of the SOGI and LKF, respectively, are provided by the frequency locked loop (FLL). The proposed technique provides better results to reject the DC offset and harmonics as compared to the multiple SOGI (MSOGI) technique. The improved performance of the proposed technique is due to the use of LKF which not only rejects the DC offset and harmonics but also non-sensitive to the change of SOGI's gain. Synthetically generated grid voltage waveforms are used in MATLAB/Simulink to depict the superior performance of the proposed SOGI-LKF technique as compared to the MSOGI with/without offset rejection technique.
{"title":"Grid voltage offset and harmonics rejection using second order generalized integrator and kalman filter technique","authors":"M. S. Reza, M. Ciobotaru, V. Agelidis","doi":"10.1109/IPEMC.2012.6258864","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6258864","url":null,"abstract":"This paper proposes the application of second order generalized integrator (SOGI) and Kalman filter (KF) technique for the rejection of DC offset and harmonics from the distorted grid voltage waveform. The SOGI is used to estimate the orthogonal waveforms of grid voltage fundamental frequency component. On the other hand, the linear Kalman filter (LKF) is used to reject the DC offset and harmonics present in the distorted grid voltage waveform. The resonance and harmonic frequencies of the SOGI and LKF, respectively, are provided by the frequency locked loop (FLL). The proposed technique provides better results to reject the DC offset and harmonics as compared to the multiple SOGI (MSOGI) technique. The improved performance of the proposed technique is due to the use of LKF which not only rejects the DC offset and harmonics but also non-sensitive to the change of SOGI's gain. Synthetically generated grid voltage waveforms are used in MATLAB/Simulink to depict the superior performance of the proposed SOGI-LKF technique as compared to the MSOGI with/without offset rejection technique.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123895896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6259070
Jiangang Liang, X. Zhou, Xinmin Jin, Yibin Tong, R. Cai
When multi-parallel inverters with L filter are connected to the grid through a long cable, the voltage at the point of common coupling (PCC) will be distorted due to the superposition of the voltage harmonic which are generated by different inverters. In order to solve this problem, the causes of voltage distortion are analyzed in this paper primarily. The correlation of the harmonic between the voltage in the PCC and the pulse width modulation (PWM) wave the output of the inverters is deduced, including the peak voltage, voltage harmonic, and the total harmonic distortion (THD). And then the solution of adding capacitor in the PCC is presented in this paper. Combined with the practical requirement, the method on the design the capacitor is listed. Finally, for illustration, the problems and solution for paralleled inverters are tested by simulation and experiments and the results provide the support to aforementioned theory and analysis.
{"title":"Analysis of voltage distortion for parallel PWM inverters with L filter","authors":"Jiangang Liang, X. Zhou, Xinmin Jin, Yibin Tong, R. Cai","doi":"10.1109/IPEMC.2012.6259070","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6259070","url":null,"abstract":"When multi-parallel inverters with L filter are connected to the grid through a long cable, the voltage at the point of common coupling (PCC) will be distorted due to the superposition of the voltage harmonic which are generated by different inverters. In order to solve this problem, the causes of voltage distortion are analyzed in this paper primarily. The correlation of the harmonic between the voltage in the PCC and the pulse width modulation (PWM) wave the output of the inverters is deduced, including the peak voltage, voltage harmonic, and the total harmonic distortion (THD). And then the solution of adding capacitor in the PCC is presented in this paper. Combined with the practical requirement, the method on the design the capacitor is listed. Finally, for illustration, the problems and solution for paralleled inverters are tested by simulation and experiments and the results provide the support to aforementioned theory and analysis.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"254 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114395271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The permanent magnet synchronous machine (PMSM) dynamic performance is not good in the flux-weakening operation region. The drawbacks of the conventional flux-weakening strategy were analyzed, and a compensator was added to the conventional flux-weakening strategy. The compensator is designed by using the difference of the q-axis current reference and the real current. With this method, the anti-windup control and flux-weakening control can be achieved simultaneously. The simulation and experimental results are used to demonstrate the effectiveness of the proposed flux-weakening strategy.
{"title":"An improved flux-weakening strategy for field-oriented-controlled PMSM drives","authors":"Huawei Zhou, X. Wen, Feng Zhao, Jian Zhang, Jinlei Meng","doi":"10.1109/IPEMC.2012.6259222","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6259222","url":null,"abstract":"The permanent magnet synchronous machine (PMSM) dynamic performance is not good in the flux-weakening operation region. The drawbacks of the conventional flux-weakening strategy were analyzed, and a compensator was added to the conventional flux-weakening strategy. The compensator is designed by using the difference of the q-axis current reference and the real current. With this method, the anti-windup control and flux-weakening control can be achieved simultaneously. The simulation and experimental results are used to demonstrate the effectiveness of the proposed flux-weakening strategy.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114487133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-02DOI: 10.1109/IPEMC.2012.6258774
Jianing Wang, S. D. de Haan, J. Ferreira, P. Luerkens
A major component of high voltage (HV) generators for medical X-ray machines is the HV multiplier. This is typically a Cockcroft-Walton cascade circuit, multiplying a moderately high voltage from the transformer to the final high voltage level at round 100kV. It is often equipped in a resonant converter as a part of capacitive output. Previous work shows that the parasitic capacitance of the cascade multiplier becomes highly relevant to the resonant tank. The equivalent parasitic capacitance of the multiplier has been numerically analyzed to discover its dependence on the material technologies of the HV module. However, the simplifications in the previous research, such as assumed equal voltage distribution across series connected diodes, absence of bulk capacitors etc., give limitations to validity of the equivalent capacitance characteristics. In this paper, an improved approximate capacitance network is proposed for the multiplier with parasitic capacitances to exhibit a more realistic parasitic model of the HV module. Based on the network, the equivalent capacitance of the multiplier is analytically expressed and analyzed. The relationship between the capacitance and parameters including the diode junction capacitance, the structural capacitance, the number of diodes per chain and the feeding voltage of the cascade is shown. According to the results, the capacitances of the cascade are compared for two semiconductor technologies that are silicon (Si) diode and silicon carbide (SiC) diode. Design guidelines are obtained for the minimization of the cascade capacitance.
{"title":"Analytical analysis of the equivalent parasitic capacitance of the high-voltage cascade multiplier in medical application of X-ray power generator","authors":"Jianing Wang, S. D. de Haan, J. Ferreira, P. Luerkens","doi":"10.1109/IPEMC.2012.6258774","DOIUrl":"https://doi.org/10.1109/IPEMC.2012.6258774","url":null,"abstract":"A major component of high voltage (HV) generators for medical X-ray machines is the HV multiplier. This is typically a Cockcroft-Walton cascade circuit, multiplying a moderately high voltage from the transformer to the final high voltage level at round 100kV. It is often equipped in a resonant converter as a part of capacitive output. Previous work shows that the parasitic capacitance of the cascade multiplier becomes highly relevant to the resonant tank. The equivalent parasitic capacitance of the multiplier has been numerically analyzed to discover its dependence on the material technologies of the HV module. However, the simplifications in the previous research, such as assumed equal voltage distribution across series connected diodes, absence of bulk capacitors etc., give limitations to validity of the equivalent capacitance characteristics. In this paper, an improved approximate capacitance network is proposed for the multiplier with parasitic capacitances to exhibit a more realistic parasitic model of the HV module. Based on the network, the equivalent capacitance of the multiplier is analytically expressed and analyzed. The relationship between the capacitance and parameters including the diode junction capacitance, the structural capacitance, the number of diodes per chain and the feeding voltage of the cascade is shown. According to the results, the capacitances of the cascade are compared for two semiconductor technologies that are silicon (Si) diode and silicon carbide (SiC) diode. Design guidelines are obtained for the minimization of the cascade capacitance.","PeriodicalId":236136,"journal":{"name":"Proceedings of The 7th International Power Electronics and Motion Control Conference","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114621664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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