Research on control strategies of open-winding permanent magnetic generator

This paper presents a novel integrated starter-generator system consisted of engine, open-winding permanent magnetic synchronous machine, storage battery, voltage source converter (VSC) and rectifier for overcoming the difficulties of voltage regulation and narrow speed range of conventional integrated starter-generator system based on permanent magnetic machine. In the proposed system, one side of the generator is connected to rectifier, the other side is connected to VSC for output voltage regulation. This paper studies two control strategies, i_d = 0 control and unity power factor (UPF) control, of open-winding permanent magnetic synchronous generator (PMSG) by theoretical analysis, derivation of formulas and simulation, the results indicates that the system is capable of output voltage regulation over the load and speed changes, the power of the generator, storage battery and load are balanced by the bi-directional electronic converter VSC, the power factor of generator decreases accordingly when the load current increase at i_d = 0 control strategy, and the unity power factor is obtained when UPF control strategy is taken, comparative analysis is presented at the end of this paper.