Compared to sine-wave filters, the dV/dt filters have a cut-off frequency above the switching frequency. The voltage at the motor terminals is still PWM pulse shaped, but the rise time and Upeak are reduced. They are smaller, weigh less and have a lower price compared to sine-wave filters. Furthermore, because of the smaller inductance and capacitance, the dV/dt filters introduce a negligible reactance between inverter and motor and are therefore suitable for high dynamic applications.
Quality and design
All dV/dt filters are designed and tested for operation with the VLT® AutomationDrive FC 302, VLT® AQUA Drive FC 202, and the VLT® HVAC Drive FC 102. They are designed to match the look and quality of the FC series.
Superior compared to output chokes
Output chokes cause undamped oscillations at the motor terminals which increase the risk of double pulsing and over-voltages higher than twice the DC link voltage.
The dV/dt filters are low-pass L-C filters with a well defined cut-off frequency. Therefore the ringing oscillations at the motor terminals are damped and there is a reduced risk of double pulsing and voltage peaks.
Advantages
Enclosures
Range
3 x 200 – 690 V (up to 880 A)
Mounting
Reduces dV/dt stresses
Lowers the magnetic interference propagation on surrounding cables and equipment
Low voltage drop makes dV/dt filters the ideal solution for highly dynamic applications with flux vector regulation