A Robust Dynamic Decoupling Control Scheme for PMSM Current Loops Based on Improved Sliding Mode Observer

Shen, Hanlin,Luo, Xin,Liang, Guilin,Shen, Anwen The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

A complete current loop decoupling control strategy based on a sliding mode observer (SMO) is proposed to eliminate the influence of current dynamic coupling and back electromotive force (EMF) in the vector control of permanent magnet synchronous motors. With this strategy, current dynamic decoupling and back EMF compensation can be simultaneously achieved. Unlike conventional methods, the proposed strategy can avoid the disturbances caused by the parametric variations of motor systems and maintain the advantages of proportional integral (PI) controllers, which are robust and easy to operate. An improved SMO, which uses a special PI regulator other than a linear saturation function as the equivalent control law in the boundary layer of a sliding surface, is proposed to eliminate the estimated errors caused by the quasi-sliding mode and obtain a satisfactory decoupling performance. The stability and parameter robustness of the proposed strategy are also analyzed. Physical experimental results are presented to verify the validity of the method.

A Robust Dynamic Decoupling Control Scheme for PMSM Current Loops Based on Improved Sliding Mode Observer

Hanlin Shen,Xin Luo,Guilin Liang,Anwen Shen 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

A complete current loop decoupling control strategy based on a sliding mode observer (SMO) is proposed to eliminate the influence of current dynamic coupling and back electromotive force (EMF) in the vector control of permanent magnet synchronous motors. With this strategy, current dynamic decoupling and back EMF compensation can be simultaneously achieved. Unlike conventional methods, the proposed strategy can avoid the disturbances caused by the parametric variations of motor systems and maintain the advantages of proportional integral (PI) controllers, which are robust and easy to operate. An improved SMO, which uses a special PI regulator other than a linear saturation function as the equivalent control law in the boundary layer of a sliding surface, is proposed to eliminate the estimated errors caused by the quasi-sliding mode and obtain a satisfactory decoupling performance. The stability and parameter robustness of the proposed strategy are also analyzed. Physical experimental results are presented to verify the validity of the method.

A Double Bi-Quad Filter with Wide-Band Resonance Suppression for Servo Systems

Xin Luo,Anwen Shen,Renchao Mao 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, “double bi-quad filter.” The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

MTPA-based high-frequency square wave voltage signal injection strategy for IPMSM control

Zhang, Zeyu,Shen, Anwen,Li, Peihe,Luo, Xin,Tang, Qipeng The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.10

This paper proposes a high-frequency (HF) square wave voltage signal injection strategy for interior permanent magnet synchronous motor (IPMSM) maximum torque per ampere (MTPA) drives. Unlike previous methods, this strategy injects a square wave HF signal into the voltage directly regardless of the current loop bandwidth limitations. In addition, the injected frequency can surpass the cut-off frequency of the current loop. Therefore, the disturbance caused by the injected signal can be reduced. The process of MTPA operating point adjustment only needs to sample and analyze the current amplitude without additional digital filters. Thus, the dynamic response promotes, and avoids the extra hardware and calculation burden. To decrease the convergence time when the load changes rapidly, an equivalent mathematical model of an IPMSM is employed to provide prior current references. Both simulation and experimental results confirm the validity and feasibility of the proposed strategy.

A Double Bi-Quad Filter with Wide-Band Resonance Suppression for Servo Systems

Luo, Xin,Shen, Anwen,Mao, Renchao The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, "double bi-quad filter." The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

A High Efficiency Two-stage Inverter for Photovoltaic Grid-connected Generation Systems

Liu, Jiang,Cheng, Shanmei,Shen, Anwen The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.1

Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dc input voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized because additional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, the electrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposes a higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches and switching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, a contrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB. Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.

A High Efficiency Two-stage Inverter for Photovoltaic Grid-connected Generation Systems

Jiang Liu,Shanmei Cheng,Anwen Shen 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.1

Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dc input voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized because additional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, the electrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposes a higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches and switching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, a contrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB. Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.

Optimal design method for LLCL filters based on NSGA-III

Li, Baojin,Huang, Songtao,Ye, Jie,Li, Yesong,Shen, Anwen,Deng, Junli The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.5

The LLCL filter is usually used as a switching ripple suppressor since it can attenuate switching-frequency current harmonics much better than an LCL filter using lower total inductance and capacitance. However, it is more difficult to design LLCL parameters. In addition, it has a number of initial design constraints: the fundamental reactive power, the resonant frequency f_res, etc. are coupled and always contradictory, which means that designing the parameters is a Many-objective optimization problem (MaOP). The non-dominated sorting genetic algorithm-III (NSGA-III) does well in solving this kind of problem. In recent studies, the proposed methods only provide a range of parameters. Thus, obtaining certain parameters relies on experience, and using the boundary value cannot be proved optimal. However, using original NSGA-III is somewhat time-consuming for achieving specific parameters. To deal with this problem, this paper proposes a novel optimal design method for an LLCL filter based on NSGA-III with the handling of constraints. The proposed method gives a set of specific parameters and achieves a high computing efficiency. The proposed method is verified through simulations and a grid-connected inverter system based on a virtual instrument to show the effectiveness of the proposed method.

Adaptive Dual Closed Loop Speed Control with Throttle Valve Dynamics for Natural Gas Engine in Range-Extended Electric Vehicles

Xiong Wenyu,Ye Jie,Gong Qichangyi,Feng Han,Shen Anwen,Xu Jinbang 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.6

This study presents an adaptive dual closed-loop speed control strategy for the natural gas engine used in a range extender to improve the robustness against parameter uncertainties, unmodeled dynamics and unknown disturbance. Compared to existing methods, this strategy takes into account the influence of the throttle valve dynamics on the intake airflow in the design of the inner-loop intake pressure controller, which is strongly nonlinear, and considers the inaccuracy of the output torque as well as unknown disturbance in the outer-loop speed controller design, which is more practical. Furthermore, the controller is incorporated with an adaptive strategy to overcome the uncertainty of parameters using the information of the engine speed and the intake pressure. Theoretical analysis indicates that this strategy can meet the demands of the wide range speed regulation of the range extender engine without knowing the specific values of the engine parameters. Moreover, the capability of the proposed controller to preserve the performance in the presence of disturbance in various working conditions is evaluated by co-simulation on the platform of Matlab/Simulink with GTpower and experiments on a range extender.