Novel Feedback-Based Selected Harmonic Elimination Technique for Single-Phase Symmetric PWM Inverters

This paper presents a novel feedback-based selected harmonic elimination (SHE) technique for using in single-phase symmetric pulse-width modulation (PWM) inverters. The novelty of the proposed technique is that it is implemented as a closed loop system. It means that it uses the solution of a set of transcendental equations as the initial optimal switching angles to start an exact smart feedback-based process to compensate the probable differences between the actual optimal switching angles and the theoretical computed optimal switching angles. For first time, the proposed technique can completely eliminate the selected voltage harmonics for both resistive and inductive loads. To check the theoretical results, the proposed technique is implemented as a simulated circuit in Proteus 6 software environment. Based on the simulated circuit, an experimental prototype of the circuit is constructed to verify the theoretical and simulation results. There are not any limitations for the maximum output power and loads of the inverter and furthermore, it complies with international standards such as IEEE 519, ER G5/4-1 and IEC 555-2. A comparison between the results of this work and other works is presented which explicitly proves the superiority of the proposed technique.