| 摘要 |
PROBLEM TO BE SOLVED: To make the unit compact and low cost, by commonly owing a plurality of converter switching elements supplementarily connected to a power supply equipment provided with a current waveform forming circuit and an rectifying element. SOLUTION: Two converters 10A, 10B comprising a chopper commonly own a switching element Qo , and charges a capacitor C1 by raising or dropping the voltage of a DC power supply 11 with a first converter 10A and, using this as a power supply. Power is supplied to a load 12 by a second converter 10B. A current I1 to a switching element Qo by the first converter 10A becomes almost half of a sine waveform by a waveform forming circuit 13 comprising a current resonance elements constituted with added L and C. On the other hand, a current I2 of a second converter becomes an almost sawtooth waveform, a current Isw of a switching element Qo becomes an waveform with both the currents I1 and I2 added together, the maximum value increases only slightly and the current during switch-off is also low so that the switching loss becomes smaller. In consequence, the amount of withstand current of a common switching element Qo does not increase significantly and it becomes compact. |
