A New Method for Determining Reference Compensating Currents of Three-Phase Shunt Active Power Filters

Using a shunt active power filter (SAPF) has been proved as an effective method to compensate reactive power and to mitigate harmonic currents of nonlinear loads. When designing a SAPF, it is crucial to generate reference currents for determining actual compensating current injections to the point of common coupling. In contrast to the conventional instantaneous reactive power theory, which needs coordinate transformations, the new method proposed in this letter is to determine reference compensating currents based on the balance of the instantaneous reactive and active power generated in the SAPF. It is shown that the proposed method is suitable for reactive and harmonic power compensation by using a SAPF. In addition, to maintain the sinusoidal source currents this method also eliminates the need for installing energy storage devices for reactive power compensation as well as the dc source for the harmonic compensation in the active power filter. Therefore, a simpler design of the SAPF with minimal line losses can be expected.