Vector Control of Interior Permanent Magnet Synchronous Motor Using Non-Singular Terminal Sliding Mode Control

Abstract

Recently, as interest in electric vehicles has increased, a lot of research has been conducted on interior permanent magnet synchronous motors (IPMSM), which have high power density and are capable of high-speed operation. In the case of a general IPMSM control system, a PI controller is mainly used, but the gain of the PI controller is greatly affected by the motor parameters. In particular, in the case of IPMSM, it is designed to have a large salient polarity for high-speed operation, which can increase parameter uncertainty due to magnetic flux saturation. Therefore, in order to secure the robustness of the controller, a control method such as sliding mode control (SMC) is being studied. In studies applying existing SMC, various types of SMC such as terminal SMC (TSMC), non-singular terminal SMC (NTSMC), and super-twisting SMC (STSMC) are being studied to ensure finite time reachability. In this paper, a speed controller was designed to ensure finite time reachability of the sliding surface and state using NTSMC. In the process of designing the speed controller, the robustness of the system could not be guaranteed due to the uncertainty about the disturbance. Therefore, to ensure the robustness of the system, a disturbance observer was designed to ensure the robustness of the system. In addition, the current vector control algorithm for IPMSM for torque improvement and high-speed operation is also applied. Based on the torque command obtained from NTSMC, an algorithm for selecting a current vector according to the speed command of IPMSM was implemented. Finally, to verify the control system (NTSMC + disturbance observer + current vector algorithm) proposed in this paper, a control system was implemented using MATLAB/Simulink. The effectiveness of the proposed control system was verified by comparing the control performance of the existing PI controller and SMC.