Abstract
Interior permanent magnet synchronous motor (IPMSM) systems are vulnerable to uncontrolled generation (UCG) when the inverter switches loss their drive signals suddenly during flied weakening high speed operation. At this point, uncontrolled rectifier is composed by freewheel diodes in the inverter, the current comes from the motor through the rectifier, and then charges the battery. This paper develops a simple analytical model of this system firstly, and then carries out the simulation of UCG transient process to investigate the impact of the motor speed, battery capacity and other factors on UCG and feedback-power obtained throughout the process. Moreover, circuit improvement is presented in order to avoid destruction risk of the battery, motor, inverter and other relevant components during UCG.
