Predictive Control Scheme With Adaptive Overmodulation for a Five-Leg VSI Driving Dual PMSMs

Abstract

A dual permanent magnet synchronous motors (PMSMs) system, driven by a five-leg voltage source inverter (VSI), is considered as a feasible option for low-cost and fault tolerance application. The traditional finite-control-set model predictive control (FCS-MPC) schemes without modulator generate heavy computational burden and larger current ripple. In this article, an improved predictive control method with space vector modulation (SVM) scheme is proposed for independent control of dual-motor system. Firstly, the expected voltage vectors (VVs) of dual motors are obtained with deadbeat (DB) solution, which yields a faster dynamic response. Then, in order to reduce current ripple and eliminate candidate voltage vector traversal process, an improved modulator with adaptive overmodulation is adopted to synthesize the expected VVs. The presented SVM method solves the problem caused by the conflicting switching-states demands of common leg from dual PMSMs. Moreover, an extensive comparison is performed among the proposed control method, the existing model-based control methods, and the field-oriented control (FOC) method with proportional-integral (PI) controller. All methods are experimentally carried out in steady state and transient state. The test results indicate that the proposed control scheme with adaptive overmodulation can effectively reduce current ripple, improve voltage utilization, and preserve good dynamic performance.