Patent ID: 6269015
Filing Date: 2001-07-31
Classification: B23K,H02M

Abstract:
A power supply apparatus for an arc-utilizing apparatus, comprising:an input terminal adapted for connection to one of commercial AC power supplies in first and second groups of commercial AC power supplies, a largest effective voltage value of voltages provided by the AC power supplies in said first group being 575 V, and a largest effective voltage value of voltages provided by the AC power supplies in said second group being smaller than a smallest effective voltage value of the voltages provided by the AC power supplies in said first group;an input-side rectifier having two output terminals, said input-side rectifier rectifying a commercial AC voltage supplied from the commercial AC power supply connected to said input terminal and developing a rectified voltage between said output terminals;a pair of capacitors for smoothing the rectified voltage from said input-side rectifier;a switching arrangement for selectively connecting said pair of capacitors in series and in parallel with each other between said two output terminals of said input-side rectifier;first and second DC-to-high-frequency converters associated with respective ones of said pair of capacitors, each of said first and second DC-to-high-frequency converters including a semiconductor switching device having a conduction path, said conduction path being rendered alternately conductive and nonconductive to thereby convert a voltage across the associated capacitor into a high-frequency voltage;a transformer for voltage-transforming the high-frequency voltages from said first and second DC-to-high-frequency converters;a high-frequency-to-DC converter for converting the voltage-transformed high-frequency voltage from said transformer to a DC voltage and applying the DC voltage to said arc-utilizing apparatus; anda switching control unit for controlling said switching arrangement so as to connect said pair of capacitors in parallel when a commercial AC power supply providing a commercial AC voltage in said second group is connected to said input terminal, and to connect said pair of capacitors in series when a commercial AC power supply providing a commercial AC voltage in said first group is connected to said input terminal;said conduction path of each of said semiconductor switching devices of said first and second DC-to-high-frequency converters having a withstanding voltage of about 800 V.