The Experts below are selected from a list of 12546 Experts worldwide ranked by ideXlab platform
Shanhu Li - One of the best experts on this subject based on the ideXlab platform.
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space Vector overmodulation strategy for ultrasparse matrix converter based on the maximum output Voltage Vector
IEEE Transactions on Power Electronics, 2017Co-Authors: Shanhu LiAbstract:In this paper, a space-Vector overmodulation strategy for an ultrasparse matrix converter (USMC) is proposed. The maximum output Voltage Vector, which has the same phase as reference Voltage, is derived accurately in space-Vector modulation. According to the maximum output Voltage Vector, the overmodulation mode I and mode II are re-divided, the boundary Voltage transfer ratio (VTR) of which is extended to 0.954, whereas the maximum VTR of USMC remains 1, and the low-order harmonic components are reduced effectively. The overmodulation strategies in both modes are realized, respectively, by the linear superimposed principle. In addition, the harmonic characteristics of output Voltage in overmodulation mode are analyzed by the double Fourier integral transform method. It is shown that the output Voltage contains not only $({\rm 6} z_{1}\pm 1) f_{\rm{out}}$ harmonics, but also ${\rm{\vert }} f_{\rm{out}} \pm 6 z_{2}f_{\rm{in}}{\rm{\vert }}$ and $\vert (6z_{1}\pm 1) f_{\rm{out}} \pm 6 z_{2}f_{\rm{in}}{\rm{\vert }}$ harmonics. The effectiveness of the proposed overmodulation strategy and the correctness of harmonic analysis method are verified by experiments.
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Space-Vector Overmodulation Strategy for Ultrasparse Matrix Converter Based on the Maximum Output Voltage Vector
IEEE Transactions on Power Electronics, 2017Co-Authors: Shanhu LiAbstract:In this paper, a space-Vector overmodulation strategy for an ultrasparse matrix converter (USMC) is proposed. The maximum output Voltage Vector, which has the same phase as reference Voltage, is derived accurately in space-Vector modulation. According to the maximum output Voltage Vector, the overmodulation mode I and mode II are re-divided, the boundary Voltage transfer ratio (VTR) of which is extended to 0.954, whereas the maximum VTR of USMC remains 1, and the low-order harmonic components are reduced effectively. The overmodulation strategies in both modes are realized, respectively, by the linear superimposed principle. In addition, the harmonic characteristics of output Voltage in overmodulation mode are analyzed by the double Fourier integral transform method. It is shown that the output Voltage contains not only (6z1 ± 1)fout harmonics, butalso |fout ± 6z2 fin | and |(6z1 ± 1)fout ± 6z2fin | harmonics. The effectiveness of the proposed overmodulation strategy and the correctness of harmonic analysis method are verified by experiments.
Hongmei Li - One of the best experts on this subject based on the ideXlab platform.
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Continuous Voltage Vector Model-Free Predictive Current Control of Surface Mounted Permanent Magnet Synchronous Motor
IEEE Transactions on Energy Conversion, 2019Co-Authors: Yanan Zhou, Hongmei LiAbstract:To reduce the current ripples of finite control set model predictive control, this paper proposes a continuous Voltage Vector model-free predictive current control method for the surface mounted permanent magnet synchronous motor (SMPMSM). In the proposed method, the continuous phase and the amplitude of the Voltage Vector are optimized in a sequence based on their uncoupling feature, and then the steady-state current fluctuation can be reduced. Only six active Voltage Vectors are enumerated, and the optimal phase is obtained by establishing the Lagrange interpolation polynomial between the cost function and the phase of Voltage Vectors. Then, the amplitude of the Voltage Vector with the optimal phase is optimized based on the principle of minimizing the cost function, and the optimal Voltage Vector is synthesized by a three-Vector method. In addition, the ultra-local model of the SMPMSM drive system from the previous study is used to improve the robustness of the proposed method. The current dynamic and steady-state responses are demonstrated through the simulation and experimental results.
Kaiyuan Lu - One of the best experts on this subject based on the ideXlab platform.
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minimum Voltage Vector injection method for sensorless control of pmsm for low speed operations
IEEE Transactions on Power Electronics, 2016Co-Authors: Kaiyuan Lu, Sanjeet Dwivedi, Jesper Riber Rosholm, Frede BlaabjergAbstract:In this paper, a simple signal injection method is proposed for sensorless control of permanent-magnet synchronous machine (PMSM) at a low speed, which ideally requires one Voltage Vector only for position estimation. The proposed method is easy to implement, resulting in low computation burden. No filters are needed for extracting the high-frequency current signals for position estimation. The use of low-pass filters (LPFs) in the current control loop to obtain the fundamental current component is not necessary. Therefore, the control bandwidth of the inner current control loop may not need to be sacrificed. The proposed method may also be further developed to inject two opposite Voltage Vectors to reduce the effects of inverter Voltage error on the position estimation accuracy. The effectiveness of the proposed method is demonstrated by comparing with other sensorless control method. Theoretical analysis and experimental results are given for validating the proposed new sensorless control method.
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Permanent Magnet Flux Online Estimation Based on Zero-Voltage Vector Injection Method
IEEE Transactions on Power Electronics, 2015Co-Authors: Kaiyuan Lu, Sanjeet Kumar Dwivedi, Rosholm Jesper Riber, Weimin WuAbstract:In this paper, a simple and accurate method is proposed for online estimation of the rotor permanent magnet (PM) flux linkage for surface mounted PM synchronous machines. By advantageously utilizing an injected zero-Voltage Vector, the effects of inductance in estimating the PM flux linkage is eliminated. The inverter Voltage error and phase resistive Voltage drop effects are minimized by repeating the test at different speeds. Therefore, as a result, only the Voltage commands are needed for PM flux linkage estimation, resulting in great simplicity. Filtering the current ripple caused by the zero-Voltage Vector injection is not necessary. The proposed method can be used with sensored or sensorless field-oriented control strategies. The experimental results have shown a good accuracy of the proposed new method.
Yaohua Li - One of the best experts on this subject based on the ideXlab platform.
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Model Predictive Direct Torque Control of Surface PMSM System Based on Basic Voltage Vector of VSI
2019 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE), 2019Co-Authors: Yaohua Li, Qidong YangAbstract:In this paper model predictive direct torque control (MP-DTC) for surface permanent magnet synchronous motor (PMSM) direct torque control (DTC) system is proposed. Based on flux and torque's expressions of surface PMSM in stator flux reference frame, 6 basic Voltage Vectors generated by Voltage source inverter (VSI) are used as candidate Voltage Vectors. And according to values of stator flux and torque at next sampling point after applying these 6 Voltage Vector, 6 different values of cost function about stator flux and torque's error are obtained. The predictive control will select Voltage Vector corresponding to the minimum cost function as output Voltage Vector. And in order to reduce the computational burden, based on the utilization rate of 6 Voltage Vectors, the predictive control using simplified aggregate of candidate Voltage Vectors is given. Simulation results show compared with switching table, control performance of predictive control is better. And compared with predictive control using 6 basic Voltage Vectors, the proposed predictive control has almost the same control performance, but switching frequency is decreased and calculation burden is also reduced.
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Predictive control with variable amplitude of Voltage Vector of interior PMSM direct torque control system
2019 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE), 2019Co-Authors: Yaohua Li, Qidong YangAbstract:Based on stator flux and torque's expressions of interior permanent magnet synchronous motor (PMSM) direct torque control (DTC) system in stator flux frame, Voltage Vector with variable amplitude and fixed angle is used as candidate output Voltage Vector. The amplitude of stator flux and torque at next sampling point after applying Voltage Vector with different amplitude are obtained. A one-step selection algorithm is established based on the cost function of stator flux and torque's errors, which can choose Voltage Vector to minimize the cost function. More candidate Voltage Vectors will lead to better control performance, but it will cause heavier calculation burden. In this paper, control performances of interior PMSM DTC system are compared using 10 different methods to divide Voltage Vector. Considering control performance and calculation burden, dividing Voltage Vector into five equal parts to get the aggravate of 5 candidate Voltage Vectors is an ideal way. And system performance tends to be stable.
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Predictive Control with Variable Amplitude of Voltage Vector of Surface PMSM Direct Torque Control System
2018 IEEE Student Conference on Electric Machines and Systems, 2018Co-Authors: Yaohua Li, Qidong YangAbstract:Based on flux and torque's expressions of surface permanent magnet synchronous motor (PMSM) direct torque control (DTC) system, the values of stator flux and torque at next sampling point after applying Voltage Vector with different amplitude are given in this paper. And objective function of flux and torque's error is proposed which only uses the amplitude of applying Voltage Vector as the variable. The predictive control will select the optimal Voltage Vector which aims to minimize objective function. Simulation results show the PMSM DTC system under the control of proposed strategy works properly. The predictive control selects the optimal Voltage Vector from aggregate of Voltage Vectors. More selectable Voltage Vectors will lead to better control performance, but it will cause heavier calculation burden. In this paper, control performances of surface PMSM DTC system are given using 9 aggregates of selectable Voltage Vectors. Considering control performance and calculation burden, dividing Voltage Vector into three equal parts to get 3 selectable Voltage Vectors is an ideal way.
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IECON - An adaptive variable Voltage Vector switching table in PMSM DTC system
IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017Co-Authors: Yaohua Li, Yafei Qu, Xiangzhen Meng, Sen JiaoAbstract:In this paper, the effect of zero Voltage Vector in permanent magnet synchronous motors (PMSM) direct torque control (DTC) system is analyzed. As zero Voltage Vector decreases stator flux and torque slowly, when system decreases the amplitude of stator flux and torque at same time, zero Voltage Vector can be used to suppress stator flux and torque ripple at steady-state. And non-zero Voltage Vector is used to get quicker response at dynamic-state. As there are two switching state of zero Voltage Vector, a switching state selection strategy is given when zero Voltage Vector is used, which aims to minimize switching times. Thus, an adaptive variable Voltage Vector switching table is proposed. Simulation results show that PMSM DTC system can work properly under control of the proposed switching table. The switching times of the system are reduced by 55% compared with conventional switching table without zero Voltage Vector. And the system has quicker dynamic response compared with switching table only using zero Voltage Vector to decrease stator flux and torque.
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IECON - An optimal Voltage Vector selection strategy based on preictive control for the DTC in SPMSM
IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017Co-Authors: Yaohua Li, Yafei Qu, Xiangzhen Meng, Sen JiaoAbstract:In this paper, an optimal Voltage Vector selection strategy based on predictive control for the direct torque control (DTC) in surface permanent magnet synchronous motor (SPMSM) is reported. The proposed predictive control determines the angle of applied Voltage Vector from the proper Voltage Vector selection area according to cost function and uses space Vector modulation (SVM) to generate the applied Voltage Vector. As the angle of applied Voltage Vector is selected from the proper selection area, it can always satisfy the control of stator flux and torque. Simulation results show the proposed DTC strategy can work well. Compared with conventional switching table, the reported strategy, it can suppress torque ripple and reduce cost function. And due to the use of SVM, switching frequency is constant, which isn't constant using conventional switching table.
Cao Yuzhao - One of the best experts on this subject based on the ideXlab platform.
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Torque-ripple reduction of SRM using optimised Voltage Vector in DTC
IET Electrical Systems in Transportation, 2018Co-Authors: Zhao Xianchao, He Kunlun, Cao YuzhaoAbstract:High torque ripple is inherent in switched reluctance motors (SRMs) because of the motor's doubly salient structure and highly non-uniform torque and magnetisation characteristics. Direct torque control (DTC) for SRM is one of the torque ripple reduction strategies which gets wide attention for its simpleness and effectiveness. In this study, aiming at the torque ripple phenomenon of DTC for SRM, a novel method for torque-ripple reduction is proposed. With the new methods, sector zones were redivided into 9 and 12 sector zones based on six sector zones and new control rules were adopted. Consequently, the proposed methods make the selection of Voltage Vector more precise. A 12/8-pole three-phase SRM drive system was designed to verify the effectiveness of the proposed new methods. The results verified that the improved DTC algorithms with 9 and 12 sector zones could indeed minimise the torque ripple to a great extent.
