초록 ▼

A stabilized power supply unit designed to supply the power from the commercial power source as far as the commercial power source is normal but supply the power from a battery that can be made available by an automatic switching device when the commercial power source has failed, wherein the AC vol

A stabilized power supply unit designed to supply the power from the commercial power source as far as the commercial power source is normal but supply the power from a battery that can be made available by an automatic switching device when the commercial power source has failed, wherein the AC voltage from the commercial power source is rectified by a rectification circuit to obtain almost equal DC currents on both the positive and negative sides of the common line while the commercial power source is normal. Said DC voltage is chopped by the boosting chopper circuit to boost the voltage on both the positive and negative sides. The boosted voltage is converted into the AC voltage through the DC-AC inverter, and the high-frequency component of the AC voltage is compressed through the filter in order to be outputted as an AC voltage of specified frequency. When the AC voltage is not inputted due to the failure of the commercial power source, the DC voltage from the battery is applied to the DC-AC inverter in order to be converted into the AC current and outputted as the specified AC voltage through the filter. In this manner, the direct transmission circuit with a common line can be formed without including an isolation device.

대표청구항 ▼

A stabilized AC power supply comprising: rectification circuit means for converting AC input from AC supply terminals into direct current (DC); DC-AC inverter means; DC power source means for inputting DC power to said DC-AC inverter means to obtain AC output at AC output terminals when said AC inpu

A stabilized AC power supply comprising: rectification circuit means for converting AC input from AC supply terminals into direct current (DC); DC-AC inverter means; DC power source means for inputting DC power to said DC-AC inverter means to obtain AC output at AC output terminals when said AC input is interrupted; a first direct AC supply circuit connecting a first of said AC supply terminals to a first of said AC output terminals through change-over switch means; a second direct AC supply circuit connecting a second of said AC supply terminals and a second of said AC output terminals through a common connection. said rectification circuit means providing from said AC input almost equal DC voltages of positive and negative polarities relative to said common connection; boosting chopper circuit means connected between said rectification circuit means and said DC-AC inverter means for both said positive and negative polarities with respect to said common connection; said DC-AC inverter means including a pair of switching means providing half-bridge type circuit means capable of supplying almost equal voltages of opposite polarity with respect to said common connection.