Solar Photovoltaic Grid Interactive Inverter Control with Reduced Sensors Count

Abstract

This manuscript introduces a control scheme for grid interactive photovoltaic inverter system. For designing a control system for grid interfaced converters voltage and current sensors are required. The control strategy introduced does not uses a voltage sensor for measuring the grid voltage thereby reducing the sensor count. Reducing the number of sensor is more economical as it reduces the overall cost and increases energy efficiency and also the system reliability. A sinusoidal signal integrator is used for generating the reference voltage signal for grid voltage estimation unit. A proportional + resonant controller is designed to dictate the output current of the grid interfaced inverter. The objective of the current controller is to regulate the power flow between the photovoltaic source and the grid and to make the output current injected into the grid harmonic free. The control scheme introduced is assessed under a variety of operating scenarios to which it can be subjected when the solar inverter is working on a grid interfaced mode. The simulation results confirm that the control scheme estimates the voltage under all operating conditions and the proportional resonant current controller demonstrated excellent response by mitigating the injected current harmonics and enhancing the power quality.