Abstract
This paper presents the small-signal modeling and controller design of a single phase multilevel, three-port based on gallium nitride (GaN) devices for renewable energy and UPS applications. The system has two ac-port with five-level waveforms and one DC port. A small-signal model of the converter is derived by the method of state-space averaging. It is controlled with two loops, an outer voltage controller is designed to regulate the DC link voltage and inner control loop compensates the grid current to track the step change in the load current. Comparison of the closed loop simulation from the derived small-signal model and a detailed circuit model showcases the effectiveness of the small signal model. Closed loop simulation results from both the small-signal model and the detail circuit model are presented and experimental results are provided.