| 摘要 |
PROBLEM TO BE SOLVED: To provide a low price power supply for plating which ensures the plating in the uniform thickness. SOLUTION: A rectified output of an input side rectifier 32 is converted to a high frequency signal with inverters 38a, 38b. This high frequency signal is changed (transformed) in voltage with transformers 48a, 48b. When the transformed high frequency signal is positive, the transformed high frequency signal is rectified with a diode 50a or 50b to apply a positive current to a load 60. When the transformed high frequency signal is negative, the diode 50c or 50d rectifies the transformed high frequency signal to apply a negative current to the load 60. An IGBT54a is connected in series to the diodes 50a and 50b, it is then controlled for ON and OFF depending on the frequency lower than the high frequency signal. An IGBT54b is also connected in series to the diodes 50c and 50d and it is then opened, depending on the lower frequency when the IGBT54a is closed, and it is also closed depending on the lower frequency, when the IGBT54b is opened. Here, the inverters 38a, 38b are controlled synchronously with the IGBT54a, 54b, so that a value of the high frequency signal when the IGBT54b is closed becomes higher than the value when the IGBT54a is closed.
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