US3777100A - Frequency multiplying device for induction heating applications - Google Patents

Frequency multiplying device for induction heating applications Download PDF

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Publication number
US3777100A
US3777100A US00313436A US3777100DA US3777100A US 3777100 A US3777100 A US 3777100A US 00313436 A US00313436 A US 00313436A US 3777100D A US3777100D A US 3777100DA US 3777100 A US3777100 A US 3777100A
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US
United States
Prior art keywords
frequency
supply voltage
saturable reactor
multiplying device
heating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00313436A
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English (en)
Inventor
J Trine
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Elphiac SA
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Elphiac SA
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Filing date
Publication date
Application filed by Elphiac SA filed Critical Elphiac SA
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Publication of US3777100A publication Critical patent/US3777100A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/08—Control, e.g. of temperature, of power using compensating or balancing arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/02—Adaptations of transformers or inductances for specific applications or functions for non-linear operation
    • H01F38/04—Adaptations of transformers or inductances for specific applications or functions for non-linear operation for frequency changing
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B19/00—Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source
    • H03B19/03—Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source using non-linear inductance
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power

Definitions

  • the extremities of the saturable reactor are connected to those of a resonant circuit constituted by the heating inductor and a condenser in parallel therewith, through impedances such that the currents at supply frequency traversing them are of equal value and of symmetrical phases with respect to the phase of the supply voltage, the angle of each such phase being equal to 90 divided by the selected frequency multiplier and multiplied by an odd integer, so that these currents are in phase operation and their sum is nil.
  • the present invention relates to frequency multiplying devices comprising a heating inductor forming, with a condenser in parallel, a resonant circuit supplied from a source of mono-phase voltage through the intermediary of a reactor which becomes saturated when the instantaneous voltage at its limits goes beyond a certain level, this resonant circuit being tuned to an odd multiple of the frequency of the supply voltage.
  • the frequency multiplying device is characterized in that the heating inductor and the saturable reactor are each provided with a center tap or at least one of them is constituted by two identical portions without mutual induction, the supply voltage being applied between these two taps and in that the extremities of the saturable reactor are connected to those of the resonant heating circuit respectively through impedances such that the currents at supply voltage which traverse them-are of equal value and of phases symmetrical with the phase of the supply voltage, the elements of the device being furthermore selected in such a way that the angle of each of these phases is equal to 90 divided by the selected frequency multiplier and multiplied by an odd integer.
  • FIG. 1 is a diagram of the circuit of a frequency multiplying device according to the invention.
  • FIG. 2 is a vector diagram of the currents present in the circuit.
  • FIG. 1 represents an induction heating installation comprising an inductor L having a center tap and connected in parallel with a condenser C. Resistances r represent the active part of the impedance of the inductor.
  • the resonant circuit LC is connected to the extremities of a saturable reactor S having a central tap, respectively through a condenser CS and a linear reactor LS; a voltage V of frequency f is applied between the central taps of reactor S and inductor L. This voltage is supplied by an alternator A through the intermediary of an autotransformer T with adjustable taps.
  • the oscillating circuit LC is tuned to a frequency nf, n being an odd integer.
  • the condenser CS and the reactor LS are selected in such a way that the two circuits containing these two respective elements and which derive between the central taps of the reactor S and of the inductor L have reactances of equal value X and of opposite signs for the supply frequency f.
  • These two circuits on the other hand are of equal resistance R so that if the currents of frequency fin the condenser CS, in the reactor LS and in the voltage supply source V are respectively designated as I,, I, and I, these currents may be represented by the vector diagram of FIG. 2.
  • the current I which is the sum of I, and I, is in phase with the voltage V and the currents I, and I, of equal value are symmetrical with respect to the voltage V and form therewith each an angle 0:. These currents are thus out of phase with respect to each other by an angle 2a.
  • the multiplied frequency currents nf which flow in the same circuits are out of phase with each other by an angle n times greater than between I, and 1, namely by an angle 2 na. If the device is arranged in such a way that 2 not Nx 180, N being an odd integer, the currents of frequency nf in the two derivation circuits will be in phase opposition and as a consequence, their sum will be nil. Thus there will not be any currents of frequency nf in the supply source.
  • the highest rate of harmonics of order n is obtained by acting onthe voltage at the limits of the reactor S in such away as to obtain the optimum saturation conditions, which consists of acting on the voltage V by displacing the adjustable tap of the autotransformer T or by adjusting the excitation of alternator A.
  • reactor S or the inductor L or both may be constituted by two identical portions in series without mutual induction, the junction point of these two portions playing the part of the central tap.
  • Frequency multiplying device for induction heating applications comprising a heating inductor forming, with a condenser in parallel therewith, a resonant circuit supplied from a monophase voltage source through the intermediary of a saturable reactor which becomes saturated when the instantaneous voltage at its limits goes beyond a certain level, said resonant circuit being tuned to an odd multiple of the frequency of the supply voltage, characterized in that the heating inductor and the saturable reactor each comprise two identical portions without mutual induction with a junction point between said two portions, the supply voltage being ap- 2.
  • Frequency multiplying device according to claim 1, characterized in that the heating inductor and the saturable reactor each comprise a central tap and the supply voltage is applied between said two taps.
  • Frequency multiplying device characterized in that adjustable means for adjusting the supply voltage are provided to adjust the conditions of saturation of the saturable reactor to obtain the highest rate of harmonics desired.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Induction Heating (AREA)
US00313436A 1971-12-10 1972-12-08 Frequency multiplying device for induction heating applications Expired - Lifetime US3777100A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
BE776498A BE776498A (fr) 1971-12-10 1971-12-10 Dispositif multiplicateur de frequence pour applications de chauffage par induction,

Publications (1)

Publication Number Publication Date
US3777100A true US3777100A (en) 1973-12-04

Family

ID=3858994

Family Applications (1)

Application Number Title Priority Date Filing Date
US00313436A Expired - Lifetime US3777100A (en) 1971-12-10 1972-12-08 Frequency multiplying device for induction heating applications

Country Status (10)

Country Link
US (1) US3777100A (sv)
JP (1) JPS4866247A (sv)
BE (1) BE776498A (sv)
CA (1) CA949136A (sv)
DE (1) DE2260226C3 (sv)
FR (1) FR2162568B1 (sv)
GB (1) GB1416157A (sv)
IT (1) IT973957B (sv)
NL (1) NL7216682A (sv)
SE (1) SE377263B (sv)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5854473A (en) * 1993-11-15 1998-12-29 Moulinex S.A. Induction heating apparatus having an alternating current generator with a saturable choke
US20050067410A1 (en) * 2003-09-25 2005-03-31 3M Innovative Properties Company Induction heating system with resonance detection

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1698284A (en) * 1921-08-02 1929-01-08 Drahtlose Telegraphie Gmbh Arrangement for obtaining large outputs in frequency changers
US3055959A (en) * 1959-11-24 1962-09-25 Nat Res Corp Electrical device for induction furnaces

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1698284A (en) * 1921-08-02 1929-01-08 Drahtlose Telegraphie Gmbh Arrangement for obtaining large outputs in frequency changers
US3055959A (en) * 1959-11-24 1962-09-25 Nat Res Corp Electrical device for induction furnaces

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5854473A (en) * 1993-11-15 1998-12-29 Moulinex S.A. Induction heating apparatus having an alternating current generator with a saturable choke
US20050067410A1 (en) * 2003-09-25 2005-03-31 3M Innovative Properties Company Induction heating system with resonance detection
US6943330B2 (en) * 2003-09-25 2005-09-13 3M Innovative Properties Company Induction heating system with resonance detection

Also Published As

Publication number Publication date
BE776498A (fr) 1972-06-12
DE2260226C3 (de) 1978-05-03
DE2260226B2 (de) 1977-09-15
DE2260226A1 (de) 1973-06-20
GB1416157A (en) 1975-12-03
FR2162568A1 (fr) 1973-07-20
IT973957B (it) 1974-06-10
FR2162568B1 (fr) 1979-02-23
CA949136A (en) 1974-06-11
JPS4866247A (en) 1973-09-11
SE377263B (sv) 1975-06-23
NL7216682A (nl) 1973-06-13
JPS5216816B2 (sv) 1977-05-11

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