A Power Control Strategy and Supporting Capability Analysis for a Hybrid Power Supply System Composed of Open-Winding WFSG and ESS

With the increasing penetration of renewable energy, the inertia of grid is gradually decreasing, and transient support capability is seriously insufficient. To improve the inertia and transient support capability of microgrid, a hybrid power supply system composed of an open-winding wound field synchronous generator (OW-WFSG) and an energy storage system (ESS) is proposed. By analyzing the power flow of the system, a synchronous control strategy based on rotor position tracking is proposed to realize the decoupling and control of power. Meanwhile, the analysis of active power support mechanism shows that the ESS with the proposed control strategy has the characteristics of synchronous generator, which achieves further improvement of the grid inertia and frequency support capability. Moreover, to improve the voltage support capability under power grid voltage fault, a winding closure and overexcitation control is proposed, which not only utilizes the high overload capability of OW-WFSG, but also avoids overcurrent damage to the converter. Experimental results verify the effectiveness of the proposed control strategy.