Experimental investigation on the performances of a multilevel inverter using a field programmable gate array-based control system

The Field Programmable Gate Array (FPGA) represents a valid solution for the design of control systems for inverters adopted in many industry applications, because of both its high flexibility of use and its high-performance with respect to other types of digital controllers. In this context, this paper presents an experimental investigation on the harmonic content of the voltages produced by a three-phase, five level cascaded H-Bridge Multilevel inverter with an FPGA-based control board, aiming also to evaluate the performance of the FPGA through the implementation of the main common modulation techniques and the comparison between simulation and experimental results. The control algorithms are implemented by means of the VHDL programming language. The output voltage waveforms, which have been obtained by applying to the inverter the main PWM techniques, are compared in terms of THD%. Simulation and experimental results are analyzed, compared and finally discussed.