Sine wave filter – Rockwell Automation 20G PowerFlex 750-Series AC Drives User Manual
Page 183
Rockwell Automation Publication 750-RM002B-EN-P - September 2013
183
Diagnostics and Protection
Chapter 3
A method to reduce just the dV/dt is to use shielded cable between the drive and
the motor. The inherent capacitance between the lines and the shield help keep
the surge voltage at 1200V up to 600 ft with PWM drives.
Sine Wave Filter
Instead of matching impedances or reducing the dV/dt of the individual pulses
coming from the drive, create a filter that enables the lower fundamental
frequencies to pass, and block or absorb the higher frequencies caused by the fast
switching IGBTs and the carrier frequency of the PWM waveform? There are
two types that are on the market today. One that consists of an LC filter and
another that consists of output line reactors along with tuned LC sections.