Control of Parallel-connected AC to DC Converter with Droop Technique for DC Microgrid Application

This paper presents the control of a single-phase ac to dc convener using the rotating reference frame control methodology wherein the phase angle (theta) obtained from a single-phase phase-locked loop is used for axis-transformation. The I-d,I-q currents and output voltage of the converter are then controlled by PI control strategy. The dc microgrid under study consists of two modules of the ac to dc converters connected in parallel topology using droop control technique. The simulation results based on Matlab/Simulink illustrate that I-d,I-q currents can be regulated by the designed PI controllers. Therefore, zero steady state error and simple power calculation are achieved. Also, real power sharing between the two converters is fulfilled by the parallel-connected converter topology with droop controller in such a dc microgrid system. while the output voltage is maintained at 600 V by a PI controller at the secondary control level. (C) 2013 The Authors. Published by Elsevier B.V.