Open-end nine-phase machine conversion systems

This paper presents four nine-phase drive systems. A nine-phase machine is connected to four converters in an open-end winding arrangement, with one of the converters being shared by all machine groups. Because of the shared converter, the structures are only applied for machines with α = 0°. A PWM strategy is discussed in order to reduce machine torque ripple. Simulation and experimental results are performed to validate the theoretical approach.