Analysis and Control Considerations of an Open Winding IPMSM Drive in MTPA and FW Regions

Electromagnetic performance and expected operating capabilities of a conventional single inverter Interior Permanent Magnet Synchronous Motor (IPMSM) drive are evaluated and compared with dual inverter open winding IPMSM drives in Maximum Torque per Ampere (MTPA) and Field Weakening (FW) regions considering machine's nonlinearities and losses. Different real and reactive power sharing assumptions are made in the dual inverter drives, and it is shown how each of the related controllers is accordingly defined. It is demonstrated that in certain operating regions of the open winding machine's torque versus speed envelope, the original real and reactive power sharing principles and the defined controllers have to be modified, otherwise the machine may not be able to operate throughout its entire anticipated operating points.