PROCESS AND DEVICE FOR ELIMINATING OR REDUCING HARMONICS AND/OR RESONANCE OSCILLATIONS

摘要

d.c. a.c. connected in parallel to the capacitor banks CR, CS, CT supplied by the converters 1-4 having an intermediate circuit. The machine 7 forms a resonant system which is excited by the square current of the inverter 4 of the converter. In this case, the machine voltage of the additional harmonics having the frequency of the resonance point and the reference and normal harmonics at the machine current are superimposed. a.c. In the low speed range of the device 7, this excitation is removed by the optimum operating sequence of the current gap and generated by the quenching circuit 3 inside the current block. A current gap occurs at the beginning and end of each current block for attenuation of the 11th and 13th harmonics, and at the center of the current block for attenuation of the 7th harmonic. The turn-on angle reference signal [alpha] M is modified by the turn-on angle differential signal [Delta] [alpha] M for the attenuation of the fifth harmonic, in particular the excitation or available harmonics are controlled around zero or zero.