On the design of proportional resonant controllers for single-phase grid-connected inverters

Connection of distributed generations to the power grid is regulated by international standards. Proportional Resonant-type (PR) compensators are widely used for controlling single-phase grid-connected inverters. Those controllers are normally designed based on frequency response approach and system requirements such as phase margin (PM) and speed of transient response. This paper concerns the design of PR controllers for single-phase grid-connected inverters. The paper provides guidelines for performing a design leading to desirable system responses. The control system characteristics including transient response time, harmonic rejection ability, delay margin (DM), and the damping of the responses are considered to arrive at a desirable design. Comparisons of the proposed design method with a conventional one show that more robust performance over a wide range of inverter power ratings can is achieved.