Algorithm for passive power factor compensation method with differential capacitor change and reduced line transient noise

摘要

A computer-implementable control algorithm that measures: 1) the reactive power; 2) the power factor; 3) the voltage; and4) the line frequency. The algorithm calculates the differential compensation capacitance required that is either positive (capacitance to be added), or negative(capacitance to be removed). The new compensation capacitance is calculated from the sum or difference of the differential compensation capacitance and the current compensation capacitance. The algorithm compares the capacitor switching bit pattern for the current compensation capacitance and the capacitor switching bit pattern for the new compensation capacitance, and selects a capacitor switching bit map accordingly. The capacitor switch combination for the new compensation capacitance is switched in incrementally according to the capacitor switching bit map. To reach the selected capacitor switch combination, only one switch is switched at a time to minimize the line transient noise. This part of the algorithm continues to run until the PF is corrected, with the capacitor switches being switched on/off each delayed by a millisecond interval to minimize line transient noise.