Maximum voltage utilization of IPMSMs using modulating voltage scalability for wide flux weakening applications

This paper proposes the development and implementation of a hybrid maximum voltage utilization controller for interior permanent magnet synchronous motors (IPMSMs) over a wide operating region. It has a structure that combines the current vector control (CVC)-type Maximum Torque Per Ampere (MTPA) controller and the modulating voltage scaled controller (MVSC). Particularly, the current regulator is deactivated for achieving the true maximum voltage utilization in the MVSC region. The hybrid structure provides a smooth transition from the CVC to the proposed MVSC mode by deactivating the current regulator in the flux weakening region. A seamless transition to the full six-step modulation can be easily realized by adjusting a scaling gain, which can be considered a very significant merit in terms of power utilization for wide flux weakening applications. This paper also attempts to investigate the torque control accuracy under motor parameter drifts and provide how to decouple its influence using a voltage disturbance state-filter design.