Sinusoidal filter for increasing the efficiency of inverter-controlled motor systems

Sinusoidal filters or LC filters consist of a (choke) inductance (L) and a downstream (capacitor) capacity (C) and form a low-pass filter tuned exactly to the required resonance frequency. Just like dU/dt filters, they belong to the output filters, as they are also operated directly at the inverter output and before the connected drive units (motors). They are individually developed and optimised for the clock frequency of the inverter.

The name sinusoidal filter is derived from the sinusoidal output voltage. While dU/dt filters mainly reduce the rates of voltage rise, sine filters smooth the square-wave voltage pattern at the output of the frequency inverter to a sinusoidal output voltage. This arises from the PWM (pulse width modulated) signal due to the low-pass effect.

Among other things, this dampens interference pulses, voltage peaks, additional losses on components such as cables, lines, noise developments, insulation stresses on motors accordingly and increases the efficiency and service life of the entire drive system.

Our sinusoidal filters are mainly used in drives and automation technology. Customers from all over the world have been relying on TRAMAG’s high-quality wound goods for their frequency converter-controlled motor operation for years.