Comparative study of H-bridge multilevel inverters dedicated to PV

Abstract

Generally, electrics devices need alternating current. But PV generators provide direct current. So, it is necessary to use inverters. Multilevel inverters seem very suitable for this task. In this paper, we present a comparative study between three multilevel inverters: 3 levels, 5 levels and 15 levels. These inverters have the same topology and are controlled by the same law: Pulse Width Modulation (PWM). Our interest concerns the magnitude and the quality of generated voltage. The 15L multilevel inverter supplied by 36V PV gives a 230V AC voltage. So it's the most suitable for supplying normal electric equipments. Simulation with Matlab/Simulink of the inverters operation shows that: THD is independent of the value of PV voltage; the greater the number of levels is, the less THD becomes.