Patent US4780803A successfully refreshed from Google Patents.
US4780803A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High frequency generator to be used in induction heating, laser, plasma and the alike
Assignee: G H IND SA
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Filing: 1986-10-22
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Granted: 1988-10-25
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Expires: 2006-10-22
Abstract
Abstract A high frequency generator is coupled to a resonant load. An inverter is swept through a range of frequencies at reduced power. The phase difference between the load current and voltage is measured. When the phase difference is at or near zero, the resonant frequency of the load is detected and the inverter provides full power to the load. The phase difference between the load current and voltage is monitored during operation so that the operating frequency of the inverter can be changed as the resonant frequency of the load changes.
Inventors
- 👤 Enrique-Juan-Francisco Dede Garcia-Santamaria
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:38
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H05; H05B; H05B6/00; H05B6/02; H05B6/06; H02M7/4815; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
121 words
A high frequency generator for a resonant load comprising: inverter means for producing a high frequency power waveform for coupling to a resonant load; frequency generator means coupled to said inverter means for frequency sweeping said load; measuring means coupled to said load for measuring the phase difference between voltage and current in said load during said frequency sweep; control means coupled to said measuring means for determining when said phase difference is at or near zero to detect the resonant frequency of said load; and for providing a control signal indicative thereof to said inverter means, said inverter means being responsive to said control signal for producing said high frequency power waveform to said load substantially at said resonant frequency.
Claim 2
Dependent Claim
121 words
A high frequency generator for a resonant load comprising: inverter means for producing a high frequency power waveform for coupling to a resonant load; frequency generator means coupled to said inverter means for frequency sweeping said load; measuring means coupled to said load for measuring the phase difference between voltage and current in said load during said frequency sweep; control means coupled to said measuring means for determining when said phase difference is at or near zero to detect the resonant frequency of said load; and for providing a control signal indicative thereof to said inverter means, said inverter means being responsive to said control signal for producing said high frequency power waveform to said load substantially at said resonant frequency.
Claim 3
Dependent Claim
30 words
The generator of claim 1 further comprising starting means for limiting power to said invertor means and thereby to said load until said frequency is substantially at said resonant frequency.
Claim 4
Dependent Claim
14 words
The generator of claim 2 wherein said inverter means comprises a transistor bridge invertor.
Claim 5
Dependent Claim
35 words
The generator of claim 1 wherein said measuring means is continuously operable to maintain said inverter means substantially at the resonant frequency of said load as said resonance frequency changes during operation of said load.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |