Current dual-loop control for RPI with LCL filter in Micro-inverter

Abstract

In order to raise the stability and output currents performance of PV micro-inverter, a current dual-loop control was proposed for RPI with LCL filter. A new peak currents control strategy is proposed as current inner-loop control by selecting suitable control envelope curve in the paper. This peak currents control strategy can simplify the design of the three phases LCL filter and improve the close loop control stably by narrowing the range of RPI switching frequency without any auxiliary circuit. The outer loop control improves the RPI output current performance. A prototype for 400W Micro-inverter is built, simulation and experimental results is reported.