Research on grid-connected control strategy of single-phase inverter based on improved VSG

Abstract With the increasingly severe global energy challenges and growing public concern over environmental protection and sustainable social development, renewable energy power generation technologies have witnessed rapid advancement, with their installed capacity expanding year by year. Most renewable energy sources function as distributed power supplies, and their power generation characteristics, such as frequency and voltage amplitude, often differ significantly from those of the main power grid. This necessitates the use of inverters for grid connection. As a critical interface device, the design of the inverter’s grid-connected controller plays a pivotal role in determining its overall performance. Traditional inverters are prone to excessive DC-side current during load disturbances, and the implementation of amplitude-limiting strategies may lead to DC voltage collapse. Therefore, it is imperative to develop an innovative grid-connected control approach that allows the DC-side state to influence AC-side control, thereby mitigating the risk of DC voltage collapse caused by significant load fluctuations. In this paper, building upon traditional virtual synchronous machine grid-connected control, a novel grid-connected control strategy incorporating DC-side voltage feedback is proposed. This strategy effectively addresses the issue of DC voltage collapse under large load disturbances, and its feasibility is validated through PLECS simulation.