Neutral-point oscillation control based on a new audio space vector modulation (A-SVM) for DCI-NPC power amplifiers

Abstract

In this work, the oscillation or flotation in the DC-BUS neutral point in the DCI-NPC (Diode Clamped Inverter–Neutral Point Clamped) amplifiers is presented as one of the most important distortion sources. This perturbation is characterized and studied, as well as its causes and distorting effects. It is also presented two techniques of vector modulation for audio. The intelligent use of these techniques in the process of vector modulation allows to redistribute the charge of the two capacitors in the DC-BUS, allowing the control of the voltage in the neutral point of the DC-BUS, and therefore, the cancellation of the flotation and its distorting effects. Experimental and simulation results which verify these strategies are presented.