Stabilized power supply unit

• US 4,823,247 A
• Filed: 01/29/1988
• Issued: 04/18/1989
• Est. Priority Date: 06/26/1987
• Status: Expired due to Term

• Current Assignee: Yutaka Electric Mfg. Co., Ltd. (Nichicon Corporation)
• Original Assignee: Yutaka Electric Mfg. Co., Ltd. (Nichicon Corporation)
• Inventors: Tamoto, Sadaharu
• Primary Examiner(s): Wong, Peter S.
• Application Number:
  US07/150,374
• Time in Patent Office: 445 Days
• Field of Search: 363/16, 363/17, 363/98, 363/124, 363/132, 363/56, 363/63, 323/222, 323/224, 323/266, 323/268, 323/271, 323/272, 307/44, 307/48, 307/66, 307/85-87
• US Class Current: 363/16
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

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.

Claims

1. 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.

2. A stabilized power supply according to claim 1, wherein the DC power source means comprises separate batteries for the positive and negative polarities with respect to said common connection.

3. A stabilized power supply according to claim 1, wherein said DC power source means comprises a battery providing one polarity with respect to said common connection, and reverse chopper means providing the opposite polarity with respect to said common connection.

4. A stabilized power supply according to claim 1, wherein the boosting chopper circuit means comprises reactance means, rectifier means and capacitor means connected in series across said DC voltages of positive and negative polarities provided by said rectification circuit means, and switching means connected between said rectifier means and said common connection.