Analysis of negative spikes on DC-link current in voltage-source PWM inverters

The occurrence of negative spikes on the DC-link current ill voltage-source PWM inverters is newly formulated, analysed and verified. Based on the introduction of a new vector, namely the dead time vector, the occurrence of these negative current spikes can be mathematically modelled, and hence can be identified at the instant of dead time intervals, in which two phases change their switching states simultaneously and satisfy a unique condition. The theoretical results are verified by comparing with both device-oriented PSpice simulation and experimental measurement. Since the proposed analysis is so general, it can readily be applied to other PWM inverters with various switching schemes.