Zero-sequence current suppression for parallel-connected open-winding permanent magnet synchronous generation system

In order to overcome the difficulties of poor voltage regulation and narrow speed range for the traditional permanent magnet synchronous machine used in the generation system, a parallel-connected open-winding topology is adopted with the inverter in series to one side of the windings and the rectifier to another side. Due to the parallel-connected dc sides of the rectifier and inverter, the zero-sequence current would flow in the windings under the conventional space vector pulse width modulation method for the voltage regulation, and it was result in the low efficiency. Therefore, the operation principle of the parallel-connected topology was given, and the causes and components of zero-sequence current for conventional space vector pulse with modulation algorithm was analyzed. Then, the hysteresis modulation method is adopted to suppress the zero-sequence current, and the suppression efficiency and feasibility of hysteresis modulation algorithm is verified by Simulation and experimental results.