A New Power Decoupling Control Strategy of Synchronverter Based on Current Feedback

Abstract

Synchronverter has the grid friendly features while simulating synchronous motor internal mechanism and external characteristics, but the coupling between active power and reactive power exacerbates synchronous frequency resonance simultaneously, which easy to cause power oscillation and may lead to system instability. To address this problem, a small signal model for synchronous inverter power-angle characteristics is established to analyze the mechanism of generating power coupling at first. On this basis, a new type of power decoupling control method is proposed in this paper, which adds a feedback current loop in the synchronverter to dynamically compensate of coupling power. This method converts the quantity of dynamic coupling power need to compensate into the value of the dynamic compensation current. Therefore, power decoupling is realized and the steady-state error of virtual synchronous control is improved. Finally, the effectiveness and feasibility of the proposed method is validated in a normal test system comparing with experiment results.