Control Strategy of Flyback Microinverter With Hybrid Mode for PV AC Modules

Abstract

This paper presents a control strategy of a flybackmicroinverter with hybrid operationmode for photovoltaic ac modules. The proposed control strategy consists of two components: the proportional-resonant (PR) controller with the harmonic compensator (HC) and the hybrid nominal duty ratio. Compared to the conventional control strategy using the proportional-integral controller, the PR controller with HC provides a higher system gain at the fundamental and harmonic frequencies of the grid without using a high proportional gain in both operation modes. Then, it enhances the tracking speed and disturbance rejection performances satisfying the desired stability. Moreover, by applying the hybrid nominal duty ratio yielded from the proposed operationmode selection, the disturbance rejection is achieved more effectively, and the control burden is reduced. Finally, the simulation and experimental results were shown to verify the tracking speed and disturbance rejection performances of the proposed control strategy.