Harmonic and Reactive Current Cancellation with PQF
Reactive and harmonic current lead to a reduced power factor and low efficiency. In order to eliminate these problems, a parallel operated inverter system can be used to shape the mains current to a sinusoidal waveform and to increase the power factor. The SETEC active grid control principle is based on measuring the harmonic currents and compensating them by current injection in opposite phase. The compensating current is created by PWM of a two- or three- phase IGBT inverter and a DC capacitor bus. The inverter is connected to the grid via coils and a small filter circuit. In contrast to traditional capacitor circuits, the reactive compensation by active-control is continuous without transients and switching distortions, and the fast reaction guarantees for high quality of power. The compensation can be either capacitive or inductive according to the requirements of the application.
Example of a three phase Active Compensator
The picture shows a three phase grid with a non-linear load connected. The harmonic and reactive currents of the load are compensated.
