A Single Phase Grid-Integrated PV System Using Cascaded PI and PR Controller for Power Quality Improvement
Lingamaiah Malle, Arvind Mittal, Shailendra Kumar
Abstract
With tremendous increase in usage of renewable energy sources (RES) instead of fossil fuels, solar plays a vital role among all the renewable sources. Multilevel inverter allows the grid integration with better quality of power. In this work a two-stage single phase 5-level transformers-less PV grid-connected system is presented. To produce a 5-level output voltage, four main switches and one auxiliary switch is used in this topology. A DC-DC boost converter is created to raise the voltage level from solar PV system (SPV). P&O (perturb and observe) MPPT control algorithm is used to obtain the maximum power available. A cascaded PI and PR control strategy is utilized to control DC-link voltage and current. To control the five level inverter PD-PWM method is used in this paper. Synchronizing (SPV) with the grid voltage and current is achieved by using PLL (phase-locked loop). Performance of the system is investigated in both the dynamic and abnormal conditions (swag/swell). Results are carried out in MATLAB/SIMULINK platform with 2.1 kW grid-tied PV systems.