Voltage Control Optimization by Equilibrium Optimizer for Unity Power Factor Operation of Grid-Connected Three-Phase Photovoltaic Inverter

A grid-tied photovoltaic (PV) system should deliver to the grid at the constant voltage and frequency desired at the point of interconnection. In this paper, the Equilibrium Optimizer Algorithm (EOA) is used to optimize the controller to ensure unity power flow (UPF) operation in a grid-connected 3-phase PV inverter. The objective aims to minimize errors in voltage control. The UPF operation is achieved by decoupled control in the dq frame by a set of tuned proportional-integral (PI) controllers and nullifying the reactive power component of current. The incremental conductance maximum power point tracking (INC MPPT) has been implemented for extracting maximum power for change in solar irradiance and temperature. The optimal controller performance is compared with the traditional design for changes in linear and nonlinear balanced 3 phase load. The source-side variations of temperature and irradiance is also observed. The EOA optimized controller performed better than the traditional controller for the different cases of operation studied.