AC-DC converter apparatus

• US 5,771,163 A
• Filed: 11/19/1996
• Issued: 06/23/1998
• Est. Priority Date: 11/19/1996
• Status: Expired due to Term

• Current Assignee: Sansha Electric Manufacturing Company Limited
• Original Assignee: Sansha Electric Manufacturing Company Limited
• Inventors: Hashimoto, Takashi, Danjo, Kenzo, Okamoto, Shigeru, Karino, Kunio, Moriguchi, Haruo
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US08/752,302
• Time in Patent Office: 581 Days
• Field of Search: 363/71, 363/98, 363/97, 363/80, 363/79, 363/17, 363/25, 363/37, 307/82
• US Class Current: 363/71
• CPC Class Codes: H02M 1/0074 Plural converter units whose inputs are connected in series
• CPC Class Codes: H02M 3/285 Single converters with a plurality of output stages connected in parallel parallel operation of a plurality of converters in dc distribution networks H02J1/10
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer

Abstract

A DC power supply apparatus includes a rectifier circuit for rectifying an input AC voltage to develop a rectified voltage between two output terminals thereof. First and second smoothing capacitors are connected in series between the output terminals of the rectifier circuit. First and second voltages developed across the first and second capacitors are applied to first and second inverters which convert the applied voltages to high-frequency voltages, which, in turn, are applied to a transformer. The transformer develops a transformed high-frequency voltage which is converted to a DC voltage by a converter. A voltage detector detects the first and second voltages, and the detected first and second voltages are compared in a microprocessor. An inverter control circuit controls the first and second inverters in accordance with the result of comparison, in a sense to make the voltages across the first and second smoothing capacitors equal.

Claims

1. A DC power supply apparatus comprising:

rectifying means for rectifying an input AC voltage to develop a rectified voltage between two output terminals thereof;

first and second smoothing capacitors connected in series between said output terminals of said rectifying means;

first inverter means receiving a first voltage developed across said first smoothing capacitor, and second inverter means receiving a second voltage developed across said second smoothing capacitor, said first and second inverter means converting said first and second voltages into high-frequency voltages;

voltage transforming means receiving said high-frequency voltages from said first and second inverter means and developing a voltage-transformed high-frequency voltage;

converting means for converting the voltage-transformed high-frequency voltage into a DC voltage;

voltage detecting means for detecting respective ones of said first and second voltages;

comparing means for comparing the absolute value of the difference between said first and second voltages as detected by said detecting means with a reference voltage, and developing an output corresponding to the result of comparison, said reference voltage being the difference between the voltages developed across respective ones of said first and second smoothing capacitors when the voltage across one of said first and second smoothing capacitors is the rated voltage of said one smoothing capacitor; and

disabling means responsive to the output of said comparing means developed when the absolute value of the difference between said first and second voltages is larger than said reference voltage, for disabling said first and second inverter means, said disabling means having a slow response to the output of said comparing means.

2. A DC power supply apparatus comprising:

rectifying means for rectifying an input AC voltage to develop a rectified voltage between two output terminals thereof;

first and second smoothing capacitors connected in series between said output terminals of said rectifying means;

first inverter means receiving a first voltage developed across said first smoothing capacitor, and second inverter means receiving a second voltage developed across said second smoothing capacitor, said first and second inverter means converting said first and second voltages into high-frequency voltages;

voltage transforming means receiving said high-frequency voltages from said first and second inverter means and developing a voltage-transformed high-frequency voltage;

converting means for converting the voltage-transformed high-frequency voltage into a DC voltage;

voltage detecting means for detecting the respective ones of said first and second voltages;

comparing means for comparing the respective ones of said first and second voltages as detected with a reference voltage which is the rated voltage of said first and second smoothing capacitors, and developing an output corresponding to the result of comparison; and

time constant means responsive to the output of said comparing means developed when either one of said first and second voltages is larger than said reference voltage, for causing said first and second inverter means not to develop said high-frequency voltages, said time constant means having a slow response to the output of said comparing means.

3. The DC power supply apparatus according to claim 2 wherein said time constant means is responsive to the output of said comparing means developed when either one of said first and second voltages is larger than said reference voltage for disabling said first and second inverter means.

4. The DC power supply apparatus according to claim 2 wherein said time constant means is responsive to the output of said comparing means developed when either one of said first and second voltages is larger than said reference voltage for interrupting the supply of the AC voltage to said rectifying means.