Hardware Design and Implementation of FPGA Controlled Seven-Level Reduced Switch MLI

Abstract

The paper proposes the design of a seven-level reduced switch multi-level inverter (7LRS-MLI) topology. The design produces a seven-level staircase output waveform with fewer components (seven power switches), thus reducing the cost and area and improving the performance of the design, i.e. increasing efficiency and reducing switching loss effectively. Both symmetric and asymmetric configurations have been implemented and the results are discussed in the paper. A comparison of the proposed structure with other recent seven-level structures has been illustrated. The simulation (using MATLAB/SIMULINK software) and experimental validation of 7LRS-MLI also have been performed for R, RL load, change in load and change in a modulation index (MI). Field programmable gate arrays (FPGA) have been used for digital implementation of the switching waveforms which reduces design time and improves flexibility. For switching devices, the alternative phase opposite disposition pulse width modulation (APOD-PWM) technique is used at 500 Hz and 5 kHz. The voltage and current total harmonic distortion (THD) profiles are also computed during the simulation and experimental validation.