Zero body diode conduction time in variable speed drive converter systems

This paper describes a digital gate control approach for variable speed motor drive systems. The presented approach reduces body diode conduction time to zero without generation of cross conduction. The method uses a measurement impedance in series to the power devices of the converter system. This allows the direct detection of the current commutation interval and the load current direction in every half-bridge. With application of this approach we achieved an improved efficiency and electromagnetic behavior by the avoidance of body diode conduction and reverse recovery. The duration of a switching transition is minimized.