A cascaded asymmetric multilevel inverter with minimum number of switches for solar applications

Abstract

Solar energy is one of the renewable energy which is used to generate electricity with the help of PV arrays. DC-DC converter is used to step up the DC voltage from PV arrays and then it is connected to an inverter for AC applications. Conventional inverters have many issues like non sinusoidal output, high total harmonic distortion (THD), high switching stress and more number of switches. So multilevel inverter (MLI) have gained much importance over conventional inverters for high voltage and high power applications, due to the increased number of voltage levels producing less number of harmonics. In this paper, a cascaded asymmetric multilevel inverter is proposed which contains minimum number of switches and can be employed in AC applications using solar energy. The proposed topology consists of 25 output levels using 10 switches with near sinusoidal output, thereby reducing gate driver circuitry and optimizing circuit layout. Asymmetric multilevel inverter is more advantageous than symmetric multilevel inverter in obtaining more number of output levels using same number of voltage sources. The other advantages of proposed topology are low voltage stress and reduced THD. The THD for proposed inverter circuit is only 4.98%. Modeling and simulation is carried out using MATLAB/SIMULINK.