Mitigation of Voltage And Current Harmonics In Double-Stage Grid-Connected PV Plant

Due to the escalating demand for electricity in recent years, there is a desperate need for renewable energy resources that can supply a large amount of power at less cost. The Grid-connected solar PV (GCSPV) system is known for its simplicity, less maintenance and operating expenses. Boost converter employed changes the fluctuating output to a steady output. Voltage source inverter (VSI) is used to change boosted DC voltage to AC voltage. A PWM technique is adopted to regulate VSI by proper switching. Because of the presence of these power electric devices and non-linear connected loads, the generation of harmonics in the system are inevitable. These harmonics severely affect the operation of the PV system and power quality in the system. So an efficient passive LCL filter is needed to filter out the harmonics for better efficiency and power quality. The LCL filter designed in this paper decreases THD content in the grid output voltage and current to less than 1.17%. This filtered ac voltage is synchronized to the electric grid by a PLL system. The complete model a 100 kW double-stage three-phase grid-connected solar PV plant has been formulated in MATLAB, and a thorough investigation has been conducted on converter and inverter output parameters, electric grid voltage, current and power and THD percentage in inverter and grid output parameters.