| 摘要 |
PROBLEM TO BE SOLVED: To provide a direct current power supply apparatus which requires neither a reactor nor a filter for improving an input current waveform, and requires neither a resistor nor an electromagnetic contactor for controlling a charging current. SOLUTION: The apparatus is comprised of: a rectifier 1 to rectify a commercial power supply; a small capacity capacitor 2 connected to output of the rectifier 1; an inverter constituted of semiconductor switches 4a, 4b, 5a and 5b to convert the output of the rectifier 1 into alternating current; a transformer 6 to convert output of the inverter into a prescribed voltage; and diodes 7a and 7b to rectify secondary output of the transformer 6. The direct current power supply apparatus, provided with an error signal amplifier 10 and a PWM modulator 14 which perform output control, also incudes: a detection circuit to detect an alternating current part of an output voltage of the rectifier 1; a band-rejection filter 17 to eliminate six times frequency components of an alternating current power supply from an output signal of the detection circuit; and an adder 13 to add an output signal of the band-rejection filter 17 to an output signal of the error signal amplifier 10 and add the result to PWM modulator 14. COPYRIGHT: (C)2010,JPO&INPIT
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