A three-phase hybrid series passive/shunt active filter system

This paper presents a hybrid series passive/shunt active power filter system for high power nonlinear loads. This work is motivated by the limited ability of a power converter to perform effectively as an active filter by the power and the frequency distribution of the distortion for which it must compensate. The active filter system considered here is comprised of a three-phase shunt active filter and series AC line smoothing reactances installed in front of the target load. The proposed system significantly reduces the required shunt active filter bandwidth. The space-vector PWM controller for the active filter is based on a deadbeat control model. It is implemented digitally using a single 16-bit microcontroller. This controller requires only the supply current to be monitored, an approach different from conventional methods. The paper provides background on the operation of the filter, the details of the power circuit, the details of the control design, representative waveforms; and spectral performance for a filter which supports a 15 kVA phase controlled rectifier load. Experimental data indicate that the active filter typically consumes 2% or less of the average load power, suggesting that a parallel filter is an efficient compensation approach. The spectral performance shows that the active filter brings the system into compliance with IEEE 519-1992 up to the 33 ^rd harmonic for an AC line smoothing reactance of 0.13 p.u