# US 5,706,184 A · Resonant converter with a resonant circuit employing the leakage inductance and distributed capacitance of a transformer

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- Number: US 5,706,184 A
- Document ID: US5706184A
- Status: Granted
- Kind: A
- Application number: 08/478,838
- Filed: 1995-06-07
- Granted: 1998-01-06
- Earliest claimed: 1994-06-27
- Assignees: NEC Corporation
- Inventors: Tsuneo Mizuta; Kaoru Ishimoto
- Web page: https://patentgrep.com/patent/US5706184A

## CPC

- H02M 3/335: using semiconductor devices only
- H02M 3/28: using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- 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
- Y02P 80/10: Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

Secondary side leakage inductance and distributed capacity of a high voltage insulating transformer are constructively employed to function as the resonance coil and resonance condenser of a resonance converter. Increased efficiency is achieved by using a smoothing circuit of choke input construction so as not to reduce the impedance on the secondary side of the transformer.

## Claims

### Claim 1

A resonance converter comprising:
an insulating transformer, the secondary side of which is the high-voltage side of at least 1 KV;
switching means for on/off control of electric power supplied to the primary side of said insulating transformer;
smoothing-rectifying means for smoothing-rectifying induced electric power on the secondary side of said insulating transformer; and
control means, coupled to said smoothing-rectifying means, for performing on/off control of said switching means in accordance with a direct current voltage supplied from said smoothing-rectifying means; and
a resonance circuit wherein resonance is generated only by leakage inductance and distributed capacity on the secondary side of said insulating transformer.

### Claim 2 (depends on 1)

The resonance converter according to claim 1, wherein said control means is arranged to turn off said switching means when the resonance current reaches one of a minimum value and zero.

### Claim 3 (depends on 1)

The resonance converter according to claim 1, wherein a smoothing portion of said smoothing-rectifying means comprises a choke coil.

### Claim 4

A resonance converter comprising:
an insulating transformer, the secondary side of which is the high-voltage side of at least 1 KV;
switching means for on/off control of electric power supplied to the primary side of said insulating, transformer:
smoothing-rectifying means for smoothing-rectifying induced electric power on the secondary side of said insulating transformer; and
control means, coupled to said smoothing-rectifying means, for performing on/off control of said switching means in accordance with a direct current voltage supplied from said smoothing-rectifying means; and
a resonance circuit wherein resonance is generated by leakage inductance and distributed capacity on the secondary side of said insulating transformer;
wherein a condenser is connected in parallel with one of an input and an output of a rectifying portion of said smoothing-rectifying means for regulating the resonance frequency of said resonance circuit.

### Claim 5 (depends on 4)

The resonance converter according to claim 4, wherein a smoothing portion of said smoothing-rectifying means comprises a choke coil.