Selective Harmonic Mitigation Technique to Control Power Flow in Cascaded H-Bridge Multilevel Inverter with Non-equal Dc Link Voltages and Energy Storage

Abstract

This paper presents a new SHM-PWM technique based on multilevel waveforms which enables the required control of power flow in a CHB converter while fully utilizing the waveform degrees of freedom. The method uses the interpolation of LUT based solutions for a number of imbalances to control the power flow through the H-bridges asymmetrically, thus avoiding the requirement of very large LUTs apparent in previous methods. This paper also focuses on the SHM-PWM control strategy which is capable of meeting grid codes even under non-equal dc link voltages. Theoretical and simulated result is experimentally verified using a five level cascaded H-bridge topology operating as an inverter.