Time-suboptimal analysis and control of fast three-phase active filter acting in one sixth of period

The paper presents a dynamic power active parallel filter for the VAr and higher harmonics compensation of symmetrical nonharmonic/nonlinear loads. The new original thought, which has been used, is the creation of a complex vector of investigated quantities and its decomposition into real- and imaginary components. The acquisition and control circuitry of the filter can then handle fast dynamic changes of load using a discrete Fourier harmonic analysis in the complex domain. The analysis should be completed within one sixth of the period for a three-phase power system (from acquired data of previous sixth), due to six-side symmetry of complex vector. The compensator response to the actual state of the load is then very fast.