Modular Motor/Converter System Topology With Redundancy for High-Speed, High-Power Motor Applications

A novel motor/converter system topology is presented, which is ideal for high-power, high-speed motor applications, especially in the case of utilizing permanent-magnet synchronous AC motors. The proposed system utilizes space-shifted, split-phase, motor stator configuration, with a modular converter topology. The stator winding configuration allows current harmonics from the different phases to cancel out each other, while maximizing the fundamental space vector. Hence, the proposed topology does not require the high-frequency pulsewidth modulation normally needed to reduce the time-domain harmonics found in the phase currents. The switching frequency of the power converters can actually be as low as the fundamental frequency, which significantly reduces the switching losses, associated electromagnetic interference mitigation, and cooling requirements. The modularity of the proposed topology also simplifies overall system design and manufacturability, and provides redundancy and inherent fault tolerance. In this paper, the system topology and control strategy are discussed. Simulation and finite-element analysis results are presented to illustrate the harmonic cancellation and other advantages of the proposed topology. Experimental results also confirm the validity of the proposed system topology.