DV/Dt Filter, Frequency Converter Speed Control Device Protection Motor

DV/dt filter
When the PWM inverter directly drives the motor, it will generate a higher common -mode voltage 
of dv/dt, and thus generate bearing current and common mode leakage current and severe 
electromagnetic interference (EMI). Due to the influence of the distribution parameters in the 
cable, voltage reflection occurs at the motor end, resulting in coil insulation failure. The dv/dt 
filter reduces the attenuation rate of the motor cable transmission line, minimizes the peak 
voltage, and effectively reduces the high output voltage dv/dt of the IGBT converter.

Product application
dV/dT filter is for protecting the motor. Due to the long running cable between the inverter and the motor, it will cause a peak voltage that has a devastating effect on the motor. The length of the cable depends on the number of switchings of the power semiconductor and the size of the motor. If the cable is as short as 2.5 meters, the peak voltage of the motor will exceed the rated value. If the cable is too long, the problem is even bigger. In this case, a dV/dT filter is required to protect the motor from the devastating effects of the peak voltage.