Analysis of Solar Photovoltaic Powered Neutral Point Clamped Single Phase and Three Phase Five Level Inverters

Multilevel inverter (MLI) has several benefits over the conventional two-level inverter bridge like lower voltage stresses across the switches, lower harmonics, near to sinusoidal output and improved efficiency. These benefits enable inverter design to use a lower rating of devices thus reducing the cost of the inverter even though the number of devices increases. This paper compares the performance of single-phase and three-phase neutral point clamped (NPC) inverters up to a five-level configuration with solar power as input. The inverters are designed to measure their total voltage and current harmonics, voltage stress across each switch and efficiency of the inverters using MATLAB Simulink. Moreover, both square wave and sinusoidal pulse width modulation (PWM) methods are applied on both pure resistive (R) and resistive-inductive (RL) loads for a detailed comparative analysis of the inverters. The simulation results suggest that the sinusoidal PWM method for all types of inverters gives better performance in terms of reduction in harmonics however with increased burden of computation. This paper suggests a five-level NPC inverter for most solar power applications due to its superior performance.