Particle Swarm Optimization of PI Controllers in Grid-Connected PV Conversion Cascade Based Three Levels NPC Inverter

Abstract

In this paper, the application of the Particle Swarm Optimization (PSO) method to proportional integral regulators of two-stage photovoltaic power conversion systems is presented. The photovoltaic generator is connected to a boost converter controlled by Maximum Power Point Tracking (MPPT) fuzzy logic regulator. The three-phase three-level inverter constituting the second stage of studied cascade is controlled by the vector pulse width modulation strategy. To be able to synchronize the injected current and the grid voltage, a phase-locked loop is used. Three PI regulators are used to regulate the DC bus voltage as well as the grid currents obtained after transformation in rotating dq-reference frame. The parameters of the regulators used are determined by the particle swarm optimization method.