A D-Q synchronous frame controller for single-phase inverters

This paper deals with design of a synchronous frame control strategy for single-phase inverter-based islanded distributed generation (DG) systems. Although, implementation of these regulators requires a minimum of two independent phases in the system, the required orthogonal phase is generated through the use of a first order all pass filter (APF). The essence of the proposed control strategy is to use a synchronous reference frame PI (SRFPI) controller to regulate output voltage, together with a simple inner capacitor current regulating loop to stabilize the system and a voltage-feedforward loop to improve the system robustness. A detailed design criterion for the proposed control strategy is presented base on a frequency-response approach. Finally, simulation results are presented to validate the proposed method.