Improved Minimal Harmonic Injection PWM Strategy for Dual-Three-Phase Permanent Magnet Synchronous Motors in the Overmodulation Region

In this paper, an improved overmodulation strategy for dual three-phase permanent magnet synchronous motor(dual three-phase PMSM) is proposed, which can achieve minimal harmonic injection in the case of overmodulation and greatly simplify the solution process. By injecting harmonics in the overmodulation region, the reference voltage of the fundamental subspace can be modulated while minimizing the harmonic voltage in the harmonic subspace. Minimizing the harmonic voltage is a quadratic optimization problem, and its solution process is complicated. The solving process is greatly simplified by mathematical methods in this paper, and the amplitude of the injected harmonics is guaranteed to be the smallest. Finally, the smooth switching between the linear modulation region and the overmodulation region is realized. Simulation analysis verifies the effectiveness and feasibility of the proposed strategy.