Hybrid-Modulation Hysteresis Scheme Based Decoupled Power Control of Grid-Connected Inverter

In this paper a control strategy for single-phase grid connected inverter system with LCL filter that can be used for grid-connected battery/photovoltaic system, with the target to implement decoupled active and reactive power control capability in stationary frame and inherit soft-switching behavior for higher efficiency. In order to improve system efficiency, a new hybrid-modulation based hysteresis current scheme is used to achieve soft-switching while improving the inherent zero-crossing distortion issue existing in traditional unipolar hysteresis current control. Multi proportional and resonant compensators are utilized to mitigate output low-frequency distortions further, together with a capacitor current feedback based active damping design embedded in inner loop. The proposed controller also demonstrates good robustness and immunity to distorted grid conditions.

Index Terms—Grid-connected inverter; decoupled power control; hybrid modulation; hysteresis current scheme.