| 摘要 |
PURPOSE:To instantaneously hold the specified V/F ratio by calculating the voltage drop rate of a power source voltage signal and a reference signal to generate a signal for correcting an output voltage, and controlling the output voltage of power converter on the basis of the signal. CONSTITUTION:A controller 14 is operated through a chopper having a transistor 9, a reactor 10, a capacitor 11 and a diode 12 and a constant-voltage circuit made of a control circuit 13 to pulse-width-modulate an inverter 4, thereby driving a motor 5. At this time, the controller 14 is formed to input to a waveform composite circuit 112 by detecting a power source voltage, comparing it with a voltage reference 119, calculating the drop rate of the power source voltage, calculating the correcting rate by a function generator 121 and multiplying it by the output of a frequency setter 100. Accordingly, a PWM pattern is corrected and controlled at the instantaneous power interruption time to obtain a V/F ratio, thereby enabling to perform a safety instantaneous power interruption countermeasure. |
