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Uninterrupted power supply system

  • US 4,779,007 A
  • Filed: 02/13/1987
  • Issued: 10/18/1988
  • Est. Priority Date: 02/13/1987
  • Status: Expired due to Fees
First Claim
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1. A power supply system for providing uninterrupted AC power, comprising:

  • a first input port to which to couple AC input power at a specified RMS voltage level from a primary power source, a second input port to which to couple DC input power at a specified voltage level from a backup power source, and an output port to which to conenct a device to be powered;

    fullwave rectifying means for generating a first direct current from the AC input power;

    converting means for generating a second direct current from the DC input power at an RMS voltage level approximately equal to that of the AC input power; and

    switching means for coupling a selected one of the first and second direct currents to the output port according to whether the AC input power is stabilized or interrupted, and for periodically reversing the flow of the selected direct current to the output port to thereby generate AC output power;

    wherein the switching means includes waveform analyzing means for comparing the instantaneous voltage level of the AC input power at each of a plurality of phase angles with a corresponding reference value and generating an interruption-indicating control signal if the instantaneous voltage level at any one of the phase angles falls below the corresponding reference value.

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