| 摘要 |
PURPOSE:To improve charging accuracy of a capacitor by decreasing the pulse width of a pulse signal to reduce the value of an AC output of an inverter during a period in which a set voltage is arrived after the charging voltage of the capacitor reaches a predetermined voltage. CONSTITUTION:Voltage detecting means 8 sends a detection signal of charging voltage of a capacitor C1 to a controller 4A. The pulse width of a carrier signal is W1 up to time t1 after the operation of an inverter 2 is started, the output of a booster transformer 3 is the same, and the increment of the charging voltage per one pulse is V1. Then, when the fact that the charging voltage of the capacitor C1 arrives at a predetermined voltage Vp at time t1 is detected, pulse width control means 9 sets the pulse width of the carrier signal to W2 to shorten it. Accordingly, the pulse width of the output of the transformer 3 also becomes the W2, and the increment of the charging voltage per one pulse of the carrier signal is varied to V2. When a set voltage V0 is detected at time t2, the operation of the inverter 2 is stopped. Therefore, the charging accuracy of the capacitor can be improved without loss of its circuit. |
