US5504309A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Induction heater having feedback control responsive to heat output
Assignee: Illinois Tool Works Inc
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Filing: 1994-06-07
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Granted: 1996-04-02
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Expires: 2014-06-07
Abstract
Abstract An induction heater comprises a coupled pair of inverters and an induction head for generating heat, coupled to the second inverter. The output signal of the first inverter which operates at a fixed frequency, is controlled by feedback indicative of the heat output of the induction head. A control circuit processes the feedback information to compensate for power losses in the induction head. The output of the first inverter is electrically coupled to the input of the second inverter, which operates at an adjustable frequency which is selected by the user to optimize heating. The power delivered to the induction head is dependent on the output voltage of the second inverter, which is dependent on the output signal of the first inverter.
Inventors
- 👤 Steven J. Geissler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:31
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/4807; H05; H05B; H05B6/00; H05B6/02; H05B6/04; H05B6/06
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
131 words
An induction heater comprising: a first inverter with a first output capable of providing a first output power signal having a magnitude, wherein the first inverter has a control input and the magnitude of the output power is responsive to the control input; a second inverter, coupled to the output of the first inverter, with a second output capable of providing a second output power signal; an induction head; a coupling circuit in electrical communication between the second output of the second inverter and the induction head; and a control circuit including a feedback circuit and a control output coupled to the first inverter control input, wherein the control output is responsive to the heat output of the induction head whereby the power loss in the induction head is compensated for.
Claim 2
Dependent Claim
131 words
An induction heater comprising: a first inverter with a first output capable of providing a first output power signal having a magnitude, wherein the first inverter has a control input and the magnitude of the output power is responsive to the control input; a second inverter, coupled to the output of the first inverter, with a second output capable of providing a second output power signal; an induction head; a coupling circuit in electrical communication between the second output of the second inverter and the induction head; and a control circuit including a feedback circuit and a control output coupled to the first inverter control input, wherein the control output is responsive to the heat output of the induction head whereby the power loss in the induction head is compensated for.
Claim 3
Dependent Claim
28 words
The induction heater of claim 1 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the current provided to the coupling circuit.
Claim 4
Dependent Claim
28 words
The induction heater of claim 2 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the power provided to the coupling circuit.
Claim 5
Dependent Claim
28 words
The induction heater of claim 3 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the resistive losses in the coupling circuit.
Claim 6
Dependent Claim
31 words
The induction heater of claim 4 wherein the control output is responsive to the magnitude of the resistive losses in the coupling circuit and the power provided to the coupling circuit.
Claim 7
Dependent Claim
28 words
The induction heater of claim 1 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the current provided to the induction head.
Claim 8
Dependent Claim
28 words
The induction heater of claim 6 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the power provided to the induction head.
Claim 9
Dependent Claim
28 words
The induction heater of claim 7 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the resistive losses in the induction head.
Claim 10
Dependent Claim
31 words
The induction heater of claim 8 wherein the control output is responsive to the magnitude of the resistive losses in the induction head and the power provided to the induction head.
Claim 11
Independent Claim
65 words
A method of induction heating comprising: disposing an induction head near an object to be heated; providing power to the induction head; monitoring a magnitude of resistive losses in the induction head: controlling the magnitude of the power provided in response to the resistive losses in, and the power provided to, the induction head, whereby the power loss in the induction head is compensated for.
Claim 12
Independent Claim
65 words
A method of induction heating comprising: disposing an induction head near an object to be heated; providing power to the induction head; monitoring a magnitude of resistive losses in the induction head: controlling the magnitude of the power provided in response to the resistive losses in, and the power provided to, the induction head, whereby the power loss in the induction head is compensated for.
Claim 13
Dependent Claim
42 words
The method of claim 10 including the step of monitoring the magnitude of the current provided to the induction head and wherein the magnitude of the power is controlled in response to the magnitude of the current provided to the induction head,
Claim 14
Dependent Claim
42 words
The method of claim 11 including the step of monitoring the magnitude of the power provided to the induction head and wherein the magnitude of the power is controlled in response to the magnitude of the power provided to the induction head.
Claim 15
Dependent Claim
81 words
An induction heater comprising: an induction head capable of being disposed near an object to be heated; power means for providing power to the induction head, wherein the power means is in electrical communication with the induction head; monitoring a magnitude of resistive losses in the induction head; and feedback means for controlling a magnitude of the power in response to the magnitude of resistive losses in the induction head, whereby the power loss in the induction head is compensated for.
Claim 16
Dependent Claim
81 words
An induction heater comprising: an induction head capable of being disposed near an object to be heated; power means for providing power to the induction head, wherein the power means is in electrical communication with the induction head; monitoring a magnitude of resistive losses in the induction head; and feedback means for controlling a magnitude of the power in response to the magnitude of resistive losses in the induction head, whereby the power loss in the induction head is compensated for.
Claim 17
Dependent Claim
41 words
The apparatus of claim 13 including means for monitoring the magnitude of the current provided to the induction head and controlling in the magnitude of the power signal in response to the magnitude of the current provided to the induction head.
Claim 18
Dependent Claim
41 words
The apparatus of claim 14 including means for monitoring the magnitude of the power provided to the induction head and for controlling the magnitude of the power signal in response to the magnitude of the power provided to the induction head.
Claim 19
Dependent Claim
137 words
An induction heater comprising: a power circuit capable of providing an output power signal having a magnitude, wherein the power circuit has a control input and the magnitude of the output power is responsive to the control input; an induction head; a coupling circuit in electrical communication between the power circuit and the induction head; and a control circuit including a feedback circuit and a control output coupled to the power circuit control input, wherein the feedback circuit includes means to provide a signal indicative of a magnitude of resistive losses in the coupling circuit and the induction head, and further wherein the control output is responsive to the magnitude of the resistive losses in the coupling circuit and the induction head, whereby the power loss in the coupling circuit and the induction head is compensated for.
Claim 20
Dependent Claim
137 words
An induction heater comprising: a power circuit capable of providing an output power signal having a magnitude, wherein the power circuit has a control input and the magnitude of the output power is responsive to the control input; an induction head; a coupling circuit in electrical communication between the power circuit and the induction head; and a control circuit including a feedback circuit and a control output coupled to the power circuit control input, wherein the feedback circuit includes means to provide a signal indicative of a magnitude of resistive losses in the coupling circuit and the induction head, and further wherein the control output is responsive to the magnitude of the resistive losses in the coupling circuit and the induction head, whereby the power loss in the coupling circuit and the induction head is compensated for.
Claim 21
Dependent Claim
28 words
The induction heater of claim 16 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the current provided to the coupling circuit.
Claim 22
Dependent Claim
28 words
The induction heater of claim 17 wherein the feedback circuit includes means to provide a signal indicative of the magnitude of the power provided to the coupling circuit.
References Cited (Backward Citations)
US2429819A
Cited
US3466528A
Cited
US3746825A
Cited
US3743808A
Cited
US3823362A
Cited
US3953700A
Cited
US4120712A
Cited
US4112286A
Cited
US4293363A
Cited
US4280038A
Cited
US4327268A
Cited
US4511956A
Cited
US4382275A
Cited
US4578553A
Cited
US4528057A
Cited
US4602139A
Cited
US4654495A
Cited
US4637199A
Cited
USRE33467E
Cited
US4650947A
Cited
US4677535A
Cited
US4769519A
Cited
US4668851A
Cited
US4816633A
Cited
US4847746A
Cited
US4853832A
Cited
US4950348A
Cited
US5031088A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-04-02 | 1999-10-02 | 2000-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-02 | 2003-10-02 | 2004-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-02 | 2007-10-02 | 2008-04-02 | $7700.00 | Window Closed / Lapsed |