Uncontrolled generation in different converter systems

Interior permanent magnet synchronous motor (IPMSM) systems are vulnerable to uncontrolled generation (UCG) when the inverter switches loss their drive signals suddenly during field weakening high speed operation. At this point, uncontrolled rectifier-like inverter is composed by six freewheel diodes, the current comes from the motor through the rectifier-like inverter and converter, 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 in the systems with boost DC/DC converter, buck-boost bidirectional DC/DC converter and series DC/DC converter respectively. The SOC, current and voltage of battery etc. are shown as the results of the simulation. The states of the switches in converters are changed for avoiding as much as possible the destruction risks of battery, DC/DC, inverter, motor and other relevant components and effectively charging the battery during UCG.