Selective harmonic filtering of a medium voltage six-pulse line commutated rectifier using an adaptive active power filter

Active power filter (APF) performance is affected by system delay introduced in the reference signals and/or the actual injected current. This paper introduces an adaptive control strategy for the shunt APF which is capable of mitigating specific harmonic orders and consequently achieves a low harmonic factor. The delay time is minimized or eliminated when extracting the reference current and controlling the filter current. The control technique is applied to a non-linear load represented by a 6-pulse current source converter to compensate the two dominant harmonics (5^th and 7^th) of the mains current. The simulation results are verified experimentally using a scaled low-voltage prototype.