Patent ID: 6181576
Filing Date: 2001-01-30
Classification: B23K,H02M

Abstract:
A power supply apparatus for an arc-utilizing apparatus, comprising:an input-side rectifier for rectifying an AC signal and developing a rectified signal between positive and negative output terminals thereof;a pair of smoothing capacitors connected in series between said positive and negative output terminals of said input-side rectifier;a pair of DC-to-high-frequency converters each including a semiconductor switching device, for converting DC signals supplied from associated ones of said smoothing capacitors into high-frequency signals;a pair of high-frequency-to-DC converters for converting high-frequency signals supplied from associated ones of said DC-to-high-frequency converters into DC signals for application to said arc-utilizing apparatus;signal detecting means for detecting the DC signals supplied from said high-frequency-to-DC converters to said arc-utilizing apparatus and developing DC signal representative signals representing the values of the DC signals;a pair of control means associated with respective ones of said pair of DC-to-high-frequency converters for controlling conduction periods of said semiconductor switching devices of the associated DC-to-high-frequency converters in such a manner that the DC signal representative signals applied thereto become equal to reference signals applied thereto;a voltage divider circuit comprising a pair of voltage-dividing resistors connected in series, said voltage divider circuit being connected in parallel with the series combination of said smoothing capacitors;voltage detecting means coupled between the junction of said smoothing capacitors and the junction of said voltage-dividing resistors, for detecting a voltage between said junctions and developing a detected voltage representative signal representing the detected voltage; andcorrection means receiving either said reference signal or said DC signal representative signal and being responsive to the application of said detected voltage representative signal, for correcting the value of said reference signal or DC signal representative signal applied to one of said control means so as to become different from the value of said reference signal or DC signal representative signal applied to the other of said control means.