Development of a new control strategy based on two revolving field theory for single-phase VCVSI integrated to DC microgrid

Abstract

This paper proposes a new control strategy of single-phase Voltage Controlled Voltage Source Inverter (VCVSI) based on Two Revolving Field Theory (TRFT) for integrating the single-phase static as well as dynamic ac loads to the DC Microgrid (DCMG). In the developed control scheme, the output ac voltage/current of the single-phase VCVSI has been decomposed into two counter rotating vectors, referred as Forward-Positive (FP) and Backward-Negative (BN) vectors, by using TRFT principle. The α-β components of the FP and BN rotating vectors have been obtained using the orthogonal transformation. The new control scheme, with dual controllers; one for the FP vectors and another for the BN vectors of the output ac voltage/current of the VCVSI, has been implemented into two rotating d-q synchronous reference frames, using a feed-forward and two feed-back control loops. The objective of the proposed controllers is to establish the VCVSI rated output ac voltage with low total harmonic, faster transient response after disturbances, and to ensure needed power flow from the microgrid to the single-phase loads. Simulations have been carried out to show the effectiveness of the developed control scheme along with the proposed DCMG in the islanded mode, under different operating conditions.