Selective active filters using repetitive control techniques

This paper proposes a repetitive-based controller for active power filters, which compensates selected current harmonics produced by distorting loads. The approach is based on the measurement of line currents and performs the compensation of selected harmonics using a closed-loop repetitive-based control scheme. Compared to conventional solutions, this approach allows full compensation of selected frequencies, even if the active filter has limited bandwidth, and reduced interaction with possible dynamic components of the load. Compared to synchronous frame harmonic regulations on line currents, this approach requires a simpler algorithm, whose complexity is independent on the number of compensated harmonics, and it is more suited for DSP implementation and less sensitive to rounding and quantization errors. Experimental results on a 5kVA prototype confirm the theoretical expectations.