Current control for single-phase grid-connected inverters by splitting the elements of LLCL filter

In this paper, a control strategy is applied on an LLCL filter based single-phase grid-connected voltage source inverter (VSI). This strategy includes splitting the capacitor or both capacitor and inductor on the L-C series branch of the LLCL filter into two parts and using the current flowing between the two parts as a feedback to stabilize the system. By this means, the system is simplified to a first-order one. The model of the LLCL filter based inverter is proposed and simulations of inverter with an LLCL filter based on this control strategy are conducted respectively to verify the effectiveness of the method.