The dU/dt filters reduce the dU/dt values on the motor terminal phase-to-phase voltage what is important for short motor cables.
The dU/dt filters limit pulse amplitude in phase-to-phase voltage and thus they reduce the negative impact on motor’s winding insulation.
In comparison to sine wave filters, dU/dt filters have a cut-off frequency above the switching frequency.
Better than output chokes.
Subject to voltage pulses, voltage peaks occur in the coil every time switching takes place. The output chokes may often cause undamped oscillations at the motor terminals which increase the risk of double pulsing and over-voltages. The dU/dt filters are the low-pass filters L-C type with defined cut-off frequency. Due to this the risk of pulses and overvoltage on motor’s terminals is limited and results from filter’s attenuation.