Establishing Optimized Harmonic Injection Order of Sequential Overmodulation Strategies for Seven-Phase Induction Motors

With the aim of minimizing harmonic injection, sequential overmodulation strategy has been developed recently for multiphase machines. The present study provides the first comprehensive assessment of the sequential overmodulation strategies with different optimized order. Distinctively, the sequential overmodulation strategy derived in this letter introduces harmonics into the higher order subspace at the first stage. A seven-phase induction motor is utilized as the prototype to evaluate different overmodulation strategies. In essence, comparative results determine and establish the notion that it is desirable to activate the lower harmonic subspace firstly in order to achieve the optimal harmonic injection, which further refines the theory of sequential overmodulation strategy.