Simplified Reactive Power Control for grid-connected Photovoltaic inverters

Abstract

Reactive power plays an eminent role for the power system to operate efficiently as well as securely. In order to control the reactive power by the proposed Simplified Reactive Power Control (SRPC) strategy for single-phase grid-tied Photovoltaic (PV) inverters. In this proposed SRPC strategy, the reactive power control is achieve effectively by using the Current-Mode Asynchronous Sigma-Delta Modulation (CASDM). This CASDM is adopted to enhance the current control's dynamic response, reduce both the current harmonic distortion and electromagnetic interference. In this paper, the proposed PV inverter is to extract the maximum power from the PV panels and to inject the corresponding active power into the utility grid. In the meantime, the output reactive power Q out calculated by the simplified power calculation. With both the SRPC and CASDM, the single-phase PV inverter can achieve the desired RPC with low current harmonic distortion.