Sampled energy control of a single-phase shunt active power filter synthesising a resistive load

Shunt active power filters (APF´s) are becoming an important consideration for installations where a large number of non-linear loads are responsible for failure to comply with standards for harmonic distortion of the current waveform [16, 17]. This paper is concerned with a control strategy for a voltage-fed shunt APF. A control system is proposed that uses two sampled difference-energy components to achieve good dynamic performance to changing loads. The system uses a current error driven discrete proportional hysteresis method to inject harmonic and reactive correction currents into the load so as to remove these components from the source current. Another feature of this system is that the source current remains proportional to the source voltage so that the combined load/APF appears purely resistive.