Voltage Space of Five-Phase Voltage-Source Inverters

Abstract

Multiphase systems offer several advantages over their three-phase counterparts, such as torque enhancement, fault-tolerant operation, etc. In five-phase systems, the inverter output voltage can be increased using the third harmonic, which produces the voltage vector in the x−y plane with additional torque and the zero-sequence, torque-non-producing component. The maximum voltage is obtained with a non-circular trajectory of the voltage vector in the x−y plane, while the machine's optimal operation requires its circular trajectory. The paper focuses on analyzing the space for the voltage increase with respect to the constraints given by the dc-link voltage on the one hand and by the x−y and non-zero voltage component on the other. Theoretical conclusions are verified by simulations and experimental measurements.