DSP Based Implementation of SHE-PWM For Cross-Switched Multilevel Inverter

Multilevel inverter (MLI) plays a crucial role in medium voltage and high power applications. While the usages of MLIs are continuously growing in every area of power industries, it also initiates certain challenges that require attention. The increased number of power electronic components is one of the most challenging issues for multilevel inverters. The output power quality and the semiconductor device ratings of the grid connected high power inverters are largely dependent on the number of power components. Thus, it is required to decrease the overall power components as much as possible while designing these inverters. Therefore, this paper proposes a single phase 7-level cross-switched multilevel inverter that can produce higher voltages utilizing lesser power components. In order to further improve the efficiency of this MLI and enhancing its performance, selective harmonic elimination pulse width modulation (SHE-PWM) control technique is implemented. Here, Newton Raphson algorithm is examined to calculate the switching angles for different modulation indices. The fundamental voltage is obtained by solving the equations in such a way that the desired low order harmonics are eliminated. MATLAB Simulink software has been used to perform the simulation while the hardware model was implemented using digital signal processor eZdsp528335.