| 摘要 |
PURPOSE:To suppress the fluctuation of an inverter input voltage and thus to obtain a power unit minimized for voltage fluctuation by arranging such that a control angle of a rectifier through which to supply power to inverter according to a load operation can be changed according to the control angle at no-load operation. CONSTITUTION:An alternating current from power supply is converted through a rectifier 1, a smoothing circuit 2, an inverter 3, a transformer 4, a rectifier 5 and supplied to a load 6 like X-ray tube; a control angle of the rectifier 1 is controlled by a gate circuit 8 according to a difference between an output voltage VF of the circuit 2 and a set point VP. Where there is working an X-ray tube voltage impression command signal CVS, the inverter 3 is kept operating, therefore a constant voltage controlling circuit 10 issues a control signal to change the control angle of the rectifier 1 from a value necessary for peak charging of the filter 2 to a value necessary for mean value current in accordance with a signal from a control command generating circuit 20. Where there is no signal CVS working, the circuit 10 issues a signal necessary for peak charging. |
