Analysis of dynamic characteristics and control techniques applied to permanent-magnet direct drive generator based on double time coordinate

The dynamic operating characteristics of direct drive permanent magnet synchronous generator (PMSG) were researched. A method of non-linear slope pre-charge for DC-bus voltage is proposed on purpose of protecting power electronic devices. By further analyzing, some problems of conventional control strategy for grid-connection are pointed out, and a novel analysis method named double-time coordinate system is proposed, based on which the corresponding control strategy is presented to suppress the gear twisting moment and reduce the impact of grid connected. Simulation and experimental results prove that the proposed theoretical analysis method and control strategy is effective under the platform PSCAD/EMTDC.