| 摘要 |
PURPOSE:To suppress a beat phenomenon by correcting the ignition phase of an inverter in response to the variation of a power source voltage. CONSTITUTION:An inverter is composed of a DC smoothing capacitor Cd, and an inverter body INV thereby to drive an AC motor M. A controller is com posed of adders AD1...AD2, a proportional amplifier KF, a counter CN, an ignition mode pattern memory ROM, and a gate circuit GC. In this case, the ignition phase angle theta of an inverter is corrected in response to the variation of a DC voltage. When the voltage Vd becomes higher than a reference value, an electric angle 60 deg. is narrowed, while when it becomes lower, the angle 60 deg. is widened. Thus, the fact that the voltage Vd is enhanced so that an output current is increased is suppressed by the decrease of a conduction period, while when it is reduced, it is suppressed by the increase of the period. |
