Low Distortion Multilevel Inverter for Efficient Solar PV Generation for EV Application

Renewable power generation has zero carbon emissions in various cases, but due to their default generation mode (DC power, such as in solar PV, fuel cells, etc.), these require inverters to supply the power to the ac loads. The power quality is an issue to address while doing DC/AC inversion and is also important for key EV applications such as driving EV motor. The inverters required may be of conventional 3-level, multi-pulse, or multi-level types. For the integration of discrete dc sources (such as SPV, fuel cell, etc.), multi-level inverters (MLIs) are preferred due to the various advantages of this structure. For the operation of MLIs, different modulation techniques are available in the literature viz. fundamental frequency switching or high-frequency switching. Total Harmonic Distortion (THD) in the output voltage produced by the inverter depends on the switching scheme chosen. To meet the requirement of various standards on harmonics, in this work, an optimized Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) technique is implemented for the control of a 9-level MLI. The proposed scheme improves the productivity of the inverter system as compared to Sinusoidal PWM (SPWM). In the presented scheme, THD due to odd harmonic components (including triplen harmonics) up to 49
^th
order has been minimized using Genetic Algorithm Optimization (GAO) technique by considering multiple transitions per quarter cycle. It has been observed that the THD and distinct harmonic components up to the 49
^th
order are within the limit set by various standards on harmonics. The viability of the presented scheme has been tested using analytical and simulation studies on a 9-level MLI.