Operation strategy of hybrid harmonic filter in demand-side system

The passive power filter has the following problems: (1) the source impedance may strongly affect the filtering characteristics; and (2) it may cause a series resonance and/or a parallel resonance to distort voltages. These disadvantages of the passive power filter can be improved by the combined use of active and passive power filters and by appropriately coordinating their operations. To harmonics generated by the nonlinear load, the varying frequency components are compensated by the active power filter and the fixed frequency components by the passive power filters of the proposed method. This provides a good harmonic compensation over the entire operation range for the irregularly varying frequency harmonic current generated by the nonlinear load. In addition, this arrangement suppresses parallel and series resonances. In this paper, an operation and control strategy for the proposed hybrid power filter is analyzed and simulated.