Real-time simulations of a parallel hybrid active filter with hardware-in-the-loop

This paper presents hybrid power filter (HPF) performance evaluation procedure by applying special simulation hardware for digital real-time power system simulation (RTDS). RTDS simulator enables real-time calculation of electromagnetic phenomena with calculation time step of even 1-2 μs. Special hardware makes possible of importing and exporting of electrical signals from the simulator to external equipment and therefore so called hardware-in-the-loop (HIL) testing. Such simulations provide an insight in the equipment behaviour and also the influence of this equipment to system operation. In this paper a combination of a three-phase, two-level, voltage-source converter connected in parallel with the inductor of a shunt, single-tuned, passive filter is tested. To control the active part, a proportional-resonant (PR), multi-loop controller is used. The testing has shown a remarkable usefulness of the RTDS simulator for determination of actual electrical system equipment behaviour in various system conditions.