Band-Based Multi-Step Predictive Torque Control Strategy for PMSM Drives

Abstract

The multi-step model predictive control can effectively reduce the switching frequency of inverter and improve the efficiency of motor drive system. However, the conventional multi-step model predictive control algorithm is difficult to implement in a short sampling period because of high computational complexity. In this paper, a band-based multi-step predictive torque control (BM-PTC) strategy for permanent magnet synchronous motor (PMSM) drives is proposed. On the one hand, the simplified multi-step prediction model for tracking errors of torque and stator flux is derived, and the method of reducing candidate switching sequences by band constraints is proposed, thus the computational complexity of multi-step prediction can be significantly reduced. On the other hand, the steady-state control mode and transient-state control mode are designed respectively to ensure that the system has good steady-state and dynamic performance under low switching frequency. Based on a 6-kW PMSM, the feasibility and effectiveness of the proposed strategy are verified by experiments. The proposed strategy can reduce the switching frequency by more than 37% while ensuring high performance.

Keywords

• Permanent magnet synchronous motor (PMSM)
• predictive torque control
• multi-step model predictive control
• switching frequency