PWM switching patterns for operating a 3-phase inverter bridge as a boost converter

The author describes how the boost-action of an inverter bridge is influenced by the inverter PWM switching patterns. The inverter boost-action presented assumes that the 3-phase PWM voltages at the inverter bridge output terminals are not corrupted. The maximum permissible voltage gain of the inverter boost-action is shown to be dependent upon the amplitude modulation depth and to a limited extent by the type of reference waveform used. Analysis of the reference waveforms is used to predict the inverter boost-gain and good agreement is obtained between these predictions and results obtained from analysis of PWM switching patterns. Operating bounds for the inverter boost-action are linked with the ripple associated with three-phase rectified voltages and also with the inverter boost-gain fluctuations