| 摘要 |
PURPOSE:To reduce the input current ripple of an inverter and prevent signal failure thereof by providing a function generator for generating a level signal, a triangular wave generator for generating a carrier signal having special times of the output frequency of an inverter, and a modulator for comparing and mixing both signals. CONSTITUTION:An oscillator 1 generators a pulse train synchronized with the output frequency of an inverter by a frequency command FR, and a frequency signal having at least higher than twelfth times of the frequency of the motor to a triangular wave generator 4 from an oscillator 7, thereby generating a triangular carrier signal synchronized therewith. On the other hand, the output of the oscillator 1 is applied to a sawtooth waven generator 9 to generate a sawtooth wave signal sychronized with the output frequency of the inverter. An adder 11 adds the sawtooth wave signal and the level signal of constant voltage of voltage command VR, the sum is compared with a carrier signal by a modulator 5 to generate a chopping signal. In this manner it can prevent signal failure. |
