| 摘要 |
PURPOSE:To improve the distortion rate of waveform and power factor of AC input by reducing discontinuous region in the vicinity of zero-cross point of the waveform of AC input current. CONSTITUTION:When an AC input current command signal i0 is larger than an AC input current detection signal i1, the difference is amplified through an amplifier circuit comprising an error amplifier 22 and an inversion circuit 25 to produce a difference signal (d). The difference signal (d) is fed to a pulse width modulator 23 and output therefrom is inverted through an inverting circuit 26 and delivered, as a PWM signal, to a drive circuit 24. The drive circuit 24 outputs drive pulse signals P1, P2 having such pulse width as ON interval of self-extinguishing semiconductor elements 8, 9 increases as the difference signal (d) decreases thus performing ON/OFF control of the semiconductor elements 8, 9. |
