Simplified model prediction current control strategy for permanent magnet synchronous motor

Zhang, Housheng,Zhu, Shengjie,Jiang, Junjie,Wang, Qingzhuang,Wang, Ao,Jin, Duo The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11

A simplified model predictive current control strategy based on mathematical auxiliary line method is proposed to increase the permanent magnet synchronous motor (PMSM) predictive current control system's steady-state performance while reducing the system's computational complexity. The mathematical models of current prediction, first-order compensation, and cost function are presented by analyzing the prediction current control strategy of the conventional models. Within a control cycle, the simplified model predictive current control algorithm applies two voltage vectors and omits the error calculation of cost function. The anticipated voltage of transformer obtained from the beat-free current control standard is considered the reference voltage, and the judgment of the area, where the reference voltage vector is found and the strategy for double voltage vector is selected, is put forward. The optimal voltage vector can be directly output without the error calculation of the cost function in the method, thereby effectively reducing the computation load and complexity of the system and improving the steady-state performance. Experimental results verify the validity and accuracy of the proposed simplified model of predictive current control strategy for PMSM control.

Unified coordinated control strategy for two parallel inverters TPOW‑PMSM system

Housheng Zhang,Shengjie Zhu,Duo Jin,Ao Wang,Junjie Jiang,Lanlan Yu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.2

The three-phase open-winding permanent magnet synchronous motor (TPOW-PMSM) is generally used to drive electric vehicles. The voltage vector spatial distribution and fault-tolerant topological structure of a TPOW-PMSM system with two parallel inverters are analyzed in this paper. Then, based on the unified PWM modulation algorithm, a unified coordinated control strategy based on reference voltage vector 120º decoupling control is proposed. The speed and current double closedloop control systems of two parallel inverters are designed, and a PI + repetitive controller of the speed loop is designed to realize fast and stable speed control. The realization process does not require sector judgment or table lookup calculations, and the switching time of each bridge arm switch tube is determined by the instantaneous value of the three-phase voltage of the two parallel inverters, which simplifies the control algorithm. Experimental results show that the unified coordinated control strategy with the PI + repetitive controller can control the normal operation of a TPOW-PMSM, and realize smooth and reliable transitions from the normal operation state to the fault-tolerant operation state. The proposed unified coordinated control strategy with the PI + repetitive controller effectively suppresses the instantaneous value of system zero-sequence current, and inhibits the influence of the dead zone effect.

Two‑vector predictive current control strategy based on maximum torque per ampere control for PMSMs

Duo Jin,Housheng Zhang,Shengjie Zhu,Ao Wang,Junjie Jiang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8

In permanent magnet synchronous motor systems with double closed-loop maximum torque current ratio control, a PI adjuster is used as the current inner ring. Unfortunately, the current may not be tracked effectively due to controller saturation when the load suddenly changes. To counteract this effect, a novel two-vector predictive current control strategy based on maximum torque current ratio control is proposed in this paper. The control strategy introduces the model predictive current control of two voltage vectors based on maximum torque per ampere control, which is acted upon by two voltage vectors in one control period. The second selected vector is no longer limited to the null vector. The orientation and amplitude of the synthesized virtual voltage vector are adjustable. Simulation results indicate that the proposed control method has the advantages of maximum torque per ampere control and model predictive control. It optimizes the stability of the system and reduces the fluctuation of the stator current.

Simplified model predictive current control strategy for open-winding permanent magnet synchronous motor drives

Zhu, Shengjie,Zhang, Housheng The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.6

For a semi-controlled open-winding permanent magnet synchronous motor, to improve the steady-state control performance of the traditional predictive control system and to concurrently lessen the computation burden, a novel model predictive current control strategy is proposed in this paper. First, to achieve simultaneous control of the d-axis current, q-axis current, and current error-based cost functions. Then, to further reduce the calculation burden and complexity of the prediction algorithm, the predicted voltage of the converter is used as the reference voltage. In addition, the judgment of the sector where the reference voltage is located, and the selection method of the voltage vector are also given. Finally, the effectiveness of the proposed prediction method is tested by the simulation and experimental results.

Disturbance observer based non‑singular fast terminal sliding mode control of permanent magnet synchronous motors

Junjie Jiang,Housheng Zhang,Duo Jin,Ao Wang,Longhao Liu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

The existence of load disturbance can lead to the instability of permanent magnet synchronous motor (PMSM) speed control systems. Therefore, a non-singular fast terminal sliding mode control (NFTSMC) strategy based on a disturbance observer is proposed in this paper. First, a new exponential reaching law is presented to relate the rate of convergence to the state error and switching function, which achieves an improvement of the system convergence speed while reducing system jitter. At the same time, to eliminate system jitter, a new smooth saturation function is introduced in place of the symbolic function. Second, a non-singular fast terminal (NFT) sliding surface is generated by combining a nonlinear function with a linear funtion, which makes the state error converge rapidly at different stages. Finally, a disturbance observer is built to boost the robustness of the control system by observing the outside disturbance value and feeding it back to the speed controller. The dependability and effectiveness of the proposed control strategy are confirmed by simulation experiments with MATLAB.

Predictive direct torque control of permanent magnet synchronous motors using deadbeat torque and flux control

Ao Wang,Housheng Zhang,Junjie Jiang,Duo Jin,Shengjie Zhu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.2

In consideration of the shortcomings of the large torque and flux ripples in direct torque control (DTC), and the insufficient utilization of the duty cycle module in traditional DTC based on the duty cycle modulation of PMSMs, a DTC method based on deadbeat control of the torque and flux is proposed in this paper. In the synchronous rotation, coordinate system positioned with the stator flux vector, the reference voltage vector is calculated in accordance to the deadbeat control method. Six virtual voltages are constructed in such a manner that two adjacent basic voltage vectors are evenly divided in one control cycle. The effective voltage vectors are expanded to 12. The effective voltage vector closest to the phase angle of the reference voltage vector is determined to be the optimal voltage vector. Then, the duty cycle is introduced to further reduce the error between the final output voltage vector and the voltage vector required by the system. Simulation comparisons are carried out for DTC, traditional DTC based on duty cycle modulation, and the proposed DTC. The obtained simulation results demonstrate that the proposed DTC can effectively suppress both torque ripple and flux ripple, improve the utilization rate of the duty cycle module, and reduce the stator current distortion rate.

Development of Testing Device for Critical Current Measurements for HTS/LTS

Qiuliang Wang,Yinming Dai,Baozhi Zhao,Shousen Song,Zhiqiang Cao,Shunzhong Chen,Quan Zhang,Housheng Wang,Junsheng Cheng,Yuanzhong Lei,Bai Ye,Xian Li,Jianhua Liu,Shangwu Zhao,Hongjie Zhang,Xinning Hu,Ch IEEE 2009 IEEE transactions on applied superconductivity Vol.19 No.3

<P>For the goal of superconducting magnet applications in the advanced testing device for high temperature superconducting (HTS) wire and sample coils, a wide bore conduction-cooled superconducting magnet with available warm bore of phi 186 mm and center field of 5 T for the background magnetic field applications was designed and fabricated and tested. A sample cryostat with two GM cryocoolers is inserted in the background magnet. The system allows measurements to be performed in a repeatable and reliable fashion. The detailed design, fabrication and thermal analysis are presented in the paper.</P>