PMSM Current Harmonics Control Technique Based on Speed Adaptive Robust Control

The permanent magnet synchronous motor (PMSM) is widely used in electric vehicles due to its high power density. New requirements are constantly proposed with the development of PMSM, one of which is torque ripple. The current harmonic injection is a common method to minimize torque ripple. Designing an effective controller to realize current harmonic injection is the key technology. In this article, the transient voltage–current coupling equation considering magnetic saturation is derived by introducing incremental inductance. After appropriately simplifying, it is shown in form of the harmonic state space (HSS) equation. Considering that PMSM parameters vary with the current due to magnetic saturation, a robust controller is adopted to ensure stability. In order to eliminate the influence of motor speed change on control stability, the HSS is transformed into a spatial form. Then, the speed adaptive robust (SAR) controller is designed. Finally, the SAR controller is used in simulation and test bench experiments to verify dynamic response and stability. Compared with traditional PI and PR controllers, the SAR controller can ensure a good dynamic response, steady-state error, and robust stability when speed and PMSM parameters vary. Moreover, the SAR controller can well resist the harmonic coupling effect and system lag.

I. Introduction

With the rapid development of industry, the permanent magnet synchronous motor (PMSM) attracts more and more attention. New requirements, such as higher power density, smoother torque, and lower vibration, are constantly proposed. One of the most important requirements is torque ripple, which can produce powertrain vibrations and acoustic noise [1], [2]. In order to minimize torque ripple, various approaches are proposed in recent decades. The existing torque ripple minimization (TRM) approaches can be roughly categorized into two classes: the motor design approach [3]–[6] and the motor control approach. The motor control approach is more widely used since it is applicable for existing motors although the algorithm is relatively complex. The core technologies of this approach include the PMSM analytical torque equation and the current harmonic injection algorithm.