SUPERVISORY CIRCUIT OF HARMONIC DISTORTION IN POWER SUPPLY FOR SYNCHRONOUS ELECTRICAL EQUIPMENT EXCITED BY PERMANENT MAGNET

摘要

PROBLEM TO BE SOLVED: To provide a supervisory circuit to supervise harmonic distortion in power supply for a synchronous electrical equipment excited by permanent magnet which includes a rotor with no damper cage, a stator with a first, a second and a third coils, a frequency converter, and a control circuit to control the frequency converter.;SOLUTION: The supervisory circuit includes means to acquire a signal showing a current in the first coil and a signal showing a current in the second coil; a circuit to generate a synchronous pulse reflecting an electrical frequency of rotation of the rotor to the stator; a means to require a signal showing a current in the third coil; band-rejection notch filter which receives the signals showing the currents in the first, the second and the third coils respectively to reject a harmonic corresponding to the electrical frequency, and outputs respectively center frequencies servo controlled into the electrical frequency of the rotation of the rotor; measuring circuit to measure the harmonic remained in the signals output from the band-rejection notch filters; and a comparator circuit to compare a maximum value of values of the signals from the measuring circuits with a threshold.;COPYRIGHT: (C)2007,JPO&INPIT