Design and Analysis of Transformerless Grid-Tied PV Inverter with Hybrid Switching for a Wide Range of PV Voltage Adaptability

An increase in electric vehicles will be going to increase per capita energy consumption, which will encourage domestic consumers to install low-power rooftop photovoltaics (PV) systems. Many single-stage transformerless inverter topologies have been developed to increase the efficiency of PV power generation. Available multilevel transformerless single-stage inverter topologies are designed by considering regulated PV input voltage. However, PV voltage will vary in a wide range. The proposed hybrid switching technique will be able to operate at three different inverter characteristics such as Seven Level Active Neutral Point Converter (7L-ANPC) and Nine level active neutral point converter (9L-ANPC) along with the proposed 11 level voltage boosting inverter (11-LVBI) in a single inverter. This inverter is operated in a wide range of PV voltage variations without compromising RMS output voltage and harmonic limits. The common mode voltage (CMV) of the proposed inverter is constant and the leakage current is less than 30 mA, so it is well suitable for transformerless operation. The hybrid switching technique is analysed and compared with existing multilevel topologies by using MATLAB/Simulink and it’s proven that the proposed switching technique has lower harmonic content for PV voltage in the range of 220–380 V with different loading conditions. Even at 50% of the rated condition and 220 V of PV, the inverter has a low current THD of 3.7%. The proposed method is also validated with Hardware-in-the-Loop (HIL) test using OPAL-RT 4510 Simulator.