| 摘要 |
PURPOSE:To enhance reliability by providing a short pulse corrector for increasing the width of a short pulse having a pulse width shorter than predetermined time to be generated from a PWM signal forming circuit in an inverter for pulse width modulation. CONSTITUTION:An inverter controller has a speed setter 1, a controller 2, a PWM signal forming circuit 13, a short pulse corrector 7 and a short-circuit preventive time forming circuit 4. A speed command N* set by the setter 1 is converted by the controller 2 to a voltage command V*, a frequency command f*, and PWM signals U, V, W of three phases are formed by the circuit 13 from the command V*, f*. Short pulses (a), (b) might be generated in the signals U, V, W. In such a case, the pulses (a), (b) are corrected for the widths by the corrector 7 so that a main circuit switching element is not turned from ON to OFF or from OFF to ON within certain predetermined time. |
