Decoupled Alpha-Beta control for distortion reduction in three-phase low-voltage Inverters

Abstract

This paper presents an observer based control method for unbalance and harmonic compensation in three-phase three wire low voltage inverters in stand-alone mode. In the proposed control approach, unbalance compensation can be performed by controlling three-phase inverter as a pair of single-phase inverters, namely the alpha and beta channel inverters. An adaptive feed forward compensation can be incorporated in both the alpha and beta channels of the inverter to reduce the load induced harmonic distortions in the inverter output voltage. This approach is based on multi-loop control comprising voltage and current control loops applied to alpha and beta channels of the three-phase inverter. The efficacy of the proposed Decoupled Alpha-Beta (DAB) method in overcoming distortion as well as unbalance in the output voltage waveform is illustrated with simulation results. © 2020 IEEE