The Control Strategy of Open-Winding Permanent Magnet Starter-Generator With Inverter-Rectifier Topology

In order to overcome the difficulties of voltage regulation, narrow speed range, and low power factor of the traditional permanent magnet machine used in the vehicles applications, a novel inverter-rectifier topology for an open-end winding permanent magnet starter-generator is proposed. The rectifier is connected to one side of the open-end winding for the output dc voltage, and the inverter is in series to the other side for engine cranking in the start mode and the voltage regulation of the output in the generation mode. Due to the nature of the open-winding structure, the machine can flexibly change its operation from start to generation mode by the switch S. The control strategies of start and generation were analyzed separately, and a new control algorithm with a double loop for regulation of the dc voltage and current of the machine was developed. A hardware prototype of the proposed starter-generator system is built. Experimental results from this hardware prototype verify the operation principles and claims of advantages.