Design and practical implementation of a grid-connected single-stage flyback photovoltaic micro-inverter

Abstract

Grid-connected photovoltaic (PV) micro-inverters that do not require batteries are becoming increasingly popular in the market. The main issues with this type of inverter are its cost of components, such as the DC/DC converter unit, the number of sensors, and the number of switches. Accordingly, a single-stage flyback PV micro-inverter (FBPVMI) topology is considered an attractive solution for on-grid inverters. This topology requires an expensive digital control scheme to implement the synchronization stage with the grid. This chapter presents a low-cost and small-size control circuit for injecting an AC current from the inverter to the grid under various weather conditions. The proposed control strategy is based on some low-cost operational amplifiers integrated with an Arduino UNO board. The proposed control circuit is applied to the FBPVMI topology for a 120 W prototype in the laboratory. Consequently, the overall components of the suggested control circuit are verified using a Proteus simulation tool. The experimental results are obtained for the different irradiance and temperature values to validate the proposed control. Finally, the proposed topology with this control shows a good practical efficiency of 91% with excellent total harmonic distortion (THD) content of 3.7% in the output injected current. Finally, this chapter is suitable for digital technologies applications such as embedded system technology.