An Auto-Tuning Filtering Method Based on Variable Reactors

An auto-tuning filtering method based on the variable reactor is presented in this chapter. As the inductance of the traditional passive filter is constant and the capacitance is affected by temperature as well as the other external factors, the resonance frequency of the filter may deviate from the resonant point. To deal with this drawback, an auto-tuning filtering method based on the variable reactor is presented. The inductance of the variable reactor can be adjusted by adjusting the triggering angle of the thyristor, the equivalent inductance of the variable reactor would be changed automatically, and the filter would be retuned to the harmonic frequency. Simulating analysis shows that the accuracy and feasibility of this method are good. The harmonics of the power grids will be suppressed. And the power consumption of the equipment would be reduced as well.