A novel dead-time vector approach to analysis of DC link current in PWM inverter drives

Abstract

An analysis on the DC link current of space-vector PWM AC drives using novel dead-time vector (DTV) concept has been presented. By employing the DTV, a bi-value function to quantify the polarities of three phase winding currents, inverter output voltages and DC link current at dead time state can be expressed in close vectored forms. Thus, the entire drive system is considered as a whole to investigate the characteristics of DC link current at both normal and dead time states during steady and transient operations, increasingly, a phenomenon of negative spikes on DC link current caused by dead time effect is newly observed and highlighted. This phenomenon can be accurately predicted and mathematically characterized by using the proposed DTV approach. Both computer simulation and experimental results have been used for verification.