ACTIVE FILTER DEVICE AND CONTROL THEREOF

Japanese Patent JP3755220

B2

PROBLEM TO BE SOLVED: To reduce the size of a transformer which is essential in a series active filter and control the transformer easily. SOLUTION: This is a device for controlling a series type active filter 5 connected to a power supply system 1 through a transformer. The device includes a higher harmonic waveform holding means 7e which holds the higher harmonic waveforms to be compensated for and a pulse width modulation means 7g which modulates the pulse width of the active filter 5 based on the higher harmonic waves held in the higher harmonic waveform holding means 7e, and so controls the series type active filter 5 that the band of the transformer may be set in correspondence with the higher harmonic waves except for basic waves of the power supply 1.