Dynamic Modeling and Controller Design for Grid-Connected CFuk CCM Inverter with Coupled Inductor

This paper presents a dynamic modeling and controller design for a grid-connected Cuk continuous conduction mode (CCM) inverter with a coupled inductor. The primary- and secondary-side inductors of the conventional Cuk converter are integrated into one coupled inductor in the presented Cuk CCM inverter, and it reduces the number of passive components. To make the Cuk CCM inverter with a coupled inductor connected with the grid utility, an output current controller should be designed appropriately. However, the output current control of the presented Cuk inverter is difficult due to the existence of the right-half plane (RHP) zeros in its transfer function. To solve the problem, a dynamic model of the Cuk CCM inverter with a coupled inductor is developed and a repetitive controller (RC) coupled with feedback and feedforward controllers is applied to this inverter. A practical design guideline is also presented to select control parameters. Experimental results using a 200-W prototype demonstrate the acceptable performance of the proposed controller.