An SVPWM Strategy With Extended Linear Modulation Range for Dual Three-Phase Machine Drives Under Unbalanced Power Sharing Conditions

In this article, a new space vector pulsewidth modulation (SVPWM) strategy is proposed for dual three-phase (DTP) machine drives. The proposed strategy is based on vector space decomposition (VSD) and mainly targets the scenario where power of the two subthree-phase winding sets of the machine is unequal. In the basic VSD-based SVPWM strategies, the constraints of non-negative dwell time of the basic vectors result in zero linear modulation range when the DTP machine is under unbalanced power sharing conditions. Different from them, this article investigates the maximum linear modulation capability of VSD-based SVPWM under power sharing by removing the dwell time constraints of the basic vectors. In this regard, only the physical limitations of the dwell time of each phase need to be guaranteed. According to this principle, a two-step-based design procedure of the proposed modulation strategy is presented in detail, followed by a numerical analysis regarding its linear modulation boundary. Moreover, the performance comparisons with many other typical VSD-based SVPWM strategies are also conducted. It has been theoretically and experimentally proven that the proposed SVPWM solution can obtain maximum linear modulation range when the DTP machine is under unbalanced power sharing.