Sensor-less DC-Voltage Control for Grid-Connected Inverters

Three-phase grid-connected inverters using solar energy are applied very popular with large capacity. These inverters usually have input power sources in the direct current (DC) that varies according to the weather conditions. The DC voltage often needs to boost up the higher voltage level to be in accordance with the output voltage of inverters. Then, the output voltage of the DC/DC boost converter is in the form of DC voltage. In order to measure this DC value in the two-stage inverters, the existing methods usually use isolated voltage sensors. This paper presents a strategy for estimating the DC voltage value of inverters without using sensors in order to reduce cost and volume for inverters. The proposed method contributes to decreasing the price of inverters while ensuring the power quality of inverter outputs. The simulated results on MATLAB/Simulink have validated the performance of the presented solution.