A new method for separating AC component of instantaneous real power and imaginary power suitable for active filters

In a control system of active filters, p-q theory can be used for the calculation of higher harmonic currents. A high-pass filter of the first order is usually used for separating the AC components of instantaneous real power (p) and instantaneous imaginary power (q). However, in such a system the transient response for a load change is not high enough. Here, the authors propose a new control system in which the AC components are derived from p and q using a moving average value calculation method. By the proposed system, control response and accuracy are very good-even in the case of an abrupt load change.