Analyses of the DC-Link Current in Discontinuous Modulated Three-Phase Inverters

For reduction of the switching power losses developer of three-phase inverters thinks increasingly about discontinuous modulation strategies. This applies in particular for high power inverters such as for starter generator - or hybrid drive systems. The dc-link current of these discontinuous modulated voltage source inverter are analyzed in this paper. First the dc- and the rms-current of the dc-link circuit are calculated depending on the phase shift angle and the modulation factor. Afterwards the current harmonics of the dc-link circuit for a defined phase shift angle and modulation factor are determined. The calculations are verified by several circuit simulations.