A frequency shifter-based simple control for solar PV grid-interfaced system

Abstract

This paper deals with a grid-interfaced solar photovoltaic (SPV) energy conversion system for three-phase four-wire (3P4W) distribution system. The solar energy conversion system (SECS) is a multifunctional as it not only feeds SPV energy into the grid but also serves the purpose of grid current balancing, reactive power compensation, harmonic mitigation, and neutral current elimination. In a two-stage SPV system, the first stage is a boost converter, controlled with incremental conductance (InC) maximum power point tracking (MPPT) algorithm, and a second stage is a four-leg voltage source converter (VSC). A simple frequency shifter-based control is proposed for the control of VSC. A proportional integral (PI) controller along with feedforward term for SPV power is used for fast dynamic response. Simulations are carried out in MATLAB along with Simulink and Sim Power System toolboxes, and detailed simulation results are presented to demonstrate its required multifunctions.