Impact of cable and motor loads on wide bandgap device switching and reflected wave phenomenon in motor drives

In inverter based motor drives, the fast switching speeds of the power devices result in over-voltage at the motor end. Corresponding to these over-voltages at the motor end, there are over-currents at the inverter end. While the over-voltage increases stress on motor and cable insulation, the load and the cable parasitics increases the switching loss of the power devices. These effects are more pronounced in converters using Wide Bandgap (WBG) devices because of the their faster switching speed. Previous works have only studied either over-voltages or currents in converters with low source impedance. In this paper, the effect of inductive source impedance on the Reflected Wave Phenomenon (RWP) is studied. The impact of different filter topologies (used to mitigate the RWP) on the switching losses of the devices. Also, the effect of the cable parasitic including the ground and shield wires are studied here. Experiments are carried out to identify losses in different filter topologies, RWP, switching losses of devices and dv/dt at the load.