JP4719513B2 - Induction heating control device, induction heating device, and induction heating method - Google Patents

Description

  The present invention relates to an induction heating control device, an induction heating device, and an induction heating method for induction heating an object to be heated using different frequencies.

  2. Description of the Related Art Conventionally, an induction heating apparatus that supplies electric power of different frequencies to one induction heating coil to induction-heat an object to be heated is known. Such an induction heating apparatus supplies power of two different frequencies to one induction heating coil at the same time, and quenches the uneven heating surface of a heated object such as a gear (for example, Patent Document 1 or Patent Document). 2).

  The thing of patent document 1 has connected the 1st converter which supplies a high frequency, and the 2nd converter which supplies a medium frequency in parallel to one induction coil. In other words, the first converter that supplies high frequency is used as a series resonance circuit, and the medium frequency feedback from the second converter that supplies medium frequency is attenuated by a capacitor that compensates the reactive power of the induction coil in series. Yes. Further, a capacitor is connected in parallel to the second converter to compensate the reactive power of the induction coil, and between the second converter and the common contact of the first converter and the second converter. A configuration is adopted in which a series circuit of a reactor for suppressing high-frequency feedback and a capacitor for additional compensation for compensating reactive power of the reactor is connected in series. The inductance of the reactor that suppresses high-frequency feedback is set to be at least four times larger than the inductance of the induction coil.

  In Patent Document 2, a resonant capacitor is connected in parallel between output terminals of a first high-frequency power supply device that outputs heating power at a low frequency, and an output from the first high-frequency power supply device is used as a high-frequency heating coil. Is connected to the primary side of the first transformer. Further, the output from the second high-frequency power supply device that outputs the heating power at a high frequency is connected to the primary side of the second transformer that supplies the high-frequency heating coil to the high-frequency heating coil through a resonance capacitor connected in series. . Further, the secondary winding of the second transformer is connected in series between the first transformer and the high frequency heating coil, and the second high frequency power supply device is connected to the secondary side of the first transformer. A high frequency bypass capacitor for bypassing the high frequency component is connected in parallel. The heating power is supplied to the high-frequency heating coil while preventing the electric power from the low-frequency first high-frequency power supply device from leaking to the high-frequency second high-frequency power supply device, and the high-frequency second high-frequency power supply. A configuration is adopted in which heating power is supplied to the high-frequency heating coil while preventing power from the device from leaking to the first high-frequency power supply device having a low frequency.

Japanese Patent No. 3150968 (page 2 right column-page 3 right column, Fig. 3) JP 2002-356715 A (page 4 right column-page 6 right column, FIG. 1)

  However, in the conventional induction heating apparatus as described in Patent Document 1 or Patent Document 2 described above, the magnetic permeability of the object to be heated changes and is particularly high by supplying power of two different frequencies in a superimposed manner. There is a possibility that the impedance in the power source that supplies power of the frequency fluctuates and the heating efficiency is lowered. For this reason, there exists a problem that there exists a possibility that desired hardening of a to-be-heated material may not be obtained.

  In view of such problems, an object of the present invention is to provide an induction heating control device, an induction heating device, and an induction heating method capable of obtaining good induction heating.

  The induction heating control apparatus according to the present invention controls the heating apparatus for induction heating the object to be heated by supplying electric power of different frequencies from a plurality of resonance means to the induction heating coil for induction heating the object to be heated. The control device is configured to supply power to the induction heating coil by superimposing at least two frequencies with different power supplied by the resonance unit, so that a high frequency corresponding to a change in the permeability of the object to be heated can be obtained. A conversion value acquisition means for acquiring a conversion value for maintaining the power that has been supplied immediately before the supply of the power, the magnitude of which is changed by the resonance means for supplying the power, with the at least two different frequencies superimposed and supplied; And processing means for changing the supply status of the power supplied from the resonance means for supplying the high-frequency power based on the conversion value acquired by the conversion value acquisition means. Characterized in that was.

  In the present invention, power is supplied to the induction heating coil by superimposing at least two different frequencies to be supplied by a plurality of resonance means that supply power of different frequencies to the induction heating coil for induction heating the object to be heated. By means of this, the conversion value acquisition means of the control means supplies the power that changes in magnitude by the resonance means that supplies high frequency power corresponding to the magnetic permeability of the object to be heated, immediately before the supply with the frequency superimposed. The conversion value for maintaining the power state is acquired, and the supply state of the power supplied from the resonance unit that supplies high frequency power is changed by the processing unit of the control unit based on the conversion value. For this reason, by supplying power from a plurality of resonance means in a state where different frequencies are superimposed, the permeability of the resonance means for supplying power at a particularly high frequency varies due to fluctuations in the magnetic permeability of the object to be heated, resulting in power consumption. The fluctuation can be corrected well, high-frequency AC power can be stably supplied, and good induction heating efficiency can be obtained.

  In addition, the induction heating control device of the present invention controls the heating device for induction heating the object to be heated by supplying electric power of different frequencies from a plurality of resonance means to the induction heating coil for induction heating the object to be heated. An induction heating control device, wherein the impedance of the resonance means that supplies high frequency power by supplying power to the induction heating coil by superimposing at least two different frequencies of power supplied by the resonance means Corresponding to the above, the conversion value for maintaining the power state that is supplied immediately before the power of which the magnitude changes by the resonance means for supplying the power of the high frequency is supplied by superimposing the at least two different frequencies. Based on the conversion value acquired by the conversion value acquisition means and the conversion value acquired by the conversion value acquisition means, the resonance frequency supply means supplies the high frequency power. Characterized by comprising processing means for changing the Status of the force, the.

  In the present invention, power is supplied to the induction heating coil by superimposing at least two different frequencies to be supplied by a plurality of resonance means that supply power of different frequencies to the induction heating coil for induction heating the object to be heated. By means of this, the conversion value acquisition means of the control means superimposes the frequency with the power that varies in magnitude by the resonance means that supplies high frequency power corresponding to the varying impedance in the resonance means that supplies high frequency power. Supply state of power supplied from the resonance means for obtaining the conversion value for maintaining the power state supplied immediately before the supply, and supplying the high frequency power based on the conversion value by the processing means of the control means Has changed. For this reason, by supplying power from a plurality of resonance means in a state where different frequencies are superimposed, fluctuations in impedance in the resonance means that supplies power at a particularly high frequency that varies in accordance with fluctuations in the permeability of the object to be heated. As a result, it is possible to satisfactorily correct the fluctuation of the supplied power, stably supply high-frequency AC power, and obtain a good induction heating efficiency.

  And in this invention, it is preferable that the said conversion value acquisition means is set as the structure which acquires the said conversion value by a calculation. In this invention, the conversion value is calculated and acquired by the conversion value acquisition means. For this reason, for example, the conversion value may be calculated corresponding to the shape and material of the object to be heated, the quenching state, and the versatility can be improved.

  In the present invention, it is preferable that the conversion value acquisition unit reads and acquires the conversion value calculated in advance and stored in the storage unit. In this invention, the conversion value acquisition means reads and acquires the conversion value calculated in advance and stored in the storage means. For this reason, by storing the conversion value in advance, the conversion value for stably supplying high-frequency AC power can be quickly acquired, and the processing speed can be improved.

  The induction heating apparatus of the present invention includes an induction heating coil that induction-heats an object to be heated, and a plurality of resonance means that can supply power of different frequencies to the induction heating coil by superimposing at least two different frequencies. A heating device and an induction heating control device according to any one of claims 1 to 4 for controlling the resonance means of the heating device.

  According to the present invention, the resonance means in the heating apparatus including an induction heating coil for induction heating the object to be heated and a plurality of resonance means capable of supplying electric power of different frequencies with at least two different frequencies superimposed is provided. It controls by the induction heating control apparatus in any one of Claim 4 thru | or 4. Therefore, the induction heating control device according to any one of claims 1 to 4 can be used to correct the amount of fluctuation of the power supplied in a state where different frequencies are superimposed, and to stably supply high-frequency AC power. Therefore, good induction heating efficiency can be easily obtained.

  The induction heating device of the present invention includes an induction heating coil that induction-heats an object to be heated, and first resonance means that supplies electric power of a predetermined frequency to the induction heating coil to inductively heat the object to be heated. A second resonance unit for supplying power to the induction heating coil at a frequency lower than that of the first resonance unit to inductively heat the object to be heated; and a primary side connected to the first resonance unit. A transformer having a secondary side connected to the second resonance means; and a control means for controlling the first resonance means and the second resonance means to supply power of a predetermined frequency; The control means supplies the power to the induction heating coil by superimposing the frequency of the power supplied by the first resonance means and the frequency of the power supplied by the second resonance means, thereby the object to be heated. The rate of change in permeability of And controlling the amount of power supplied by the first resonator means and.

  In the present invention, the control means supplies the power of a predetermined frequency to the induction heating coil connected to the primary side of the transformer and induction-heats the object to be heated, and causes the object to be heated to be inductively heated. The second resonance means connected to the secondary side of the transformer and having a frequency lower than the frequency of the first resonance means is supplied to the induction heating coil to inductively heat the object to be heated, and the first resonance means is controlled. Corresponding to the change rate of the permeability of the object to be heated, which is changed by supplying power to the induction heating coil by superimposing the frequency of the power supplied by the resonance means and the frequency of the power supplied by the second resonance means. Thus, the magnitude of power supplied by the first resonance means is controlled. For this reason, by supplying power from the first resonance means and the second resonance means in a state where different frequencies are superimposed, the magnetic permeability of the object to be heated changes, and the first high frequency power is supplied. Even in the state where the power supplied by changing the impedance in the resonance means is changed, the power supplied by the control means is controlled and supplied, so that high-frequency power can be supplied stably and good induction heating efficiency can be obtained. .

  And in this invention, the said control means permeate | transmits the said to-be-heated material based on the ratio of the impedance of the said 1st resonance means which fluctuates by superimposing the frequency by the said 2nd resonance means and supplying electric power. It is preferable to recognize the rate of change in magnetic susceptibility and control the amount of power supplied by the first resonance means. In the present invention, the rate at which the permeability of the object to be heated changes based on the ratio of the impedance of the first resonance means that fluctuates by supplying power with the frequency superimposed by the second resonance means by the control means. And the magnitude of the power supplied by the first resonance means is controlled. For this reason, the magnitude of the power supplied by the first resonance means corresponding to the rate of change in the magnetic permeability of the object to be heated can be easily recognized by the impedance, and control for stable power supply can be facilitated.

  Furthermore, the induction heating device of the present invention includes an induction heating coil that induction-heats an object to be heated, and first resonance means that supplies electric power of a predetermined frequency to the induction heating coil to inductively heat the object to be heated. A second resonance unit for supplying power to the induction heating coil at a frequency lower than that of the first resonance unit to inductively heat the object to be heated; and a primary side connected to the first resonance unit. A transformer having a secondary side connected to the second resonance means; and a control means for controlling the first resonance means and the second resonance means to supply power of a predetermined frequency; The control means supplies the first resonance means in response to the impedance fluctuation state of the first resonance means that fluctuates by supplying power with the frequency superimposed by the second resonance means. Control the magnitude of power It is characterized in.

  In the present invention, the control means supplies the power of a predetermined frequency to the induction heating coil connected to the primary side of the transformer and induction-heats the object to be heated, and causes the object to be heated to be inductively heated. The second resonance means connected to the secondary side of the transformer and having a frequency lower than the frequency of the first resonance means is supplied to the induction heating coil to inductively heat the object to be heated; The magnitude of the power supplied by the first resonance means is controlled in accordance with the fluctuation state of the impedance of the first resonance means that fluctuates by supplying power with the frequency superimposed by the resonance means. For this reason, by supplying electric power from the first resonance means and the second resonance means in a state where different frequencies are superimposed, the impedance in the first resonance means that fluctuates in response to fluctuations in the permeability of the object to be heated. Even in a state where the power to be supplied changes due to the fluctuation of the power, the amount of power changed by the control means is controlled and supplied, so that high-frequency power can be supplied stably and good induction heating efficiency can be obtained.

  And in this invention, the said control means is the electric power supplied by the said 1st resonance means in the state by which the impedance of the said 1st resonance means is maintained in the impedance just before supplying electric power from the said 2nd resonance means. It is preferable that the size is controlled. In the present invention, the control means controls the magnitude of the power supplied by the first resonance means so that the impedance of the first resonance means is maintained at the impedance immediately before the power is supplied from the second resonance means. It is said. For this reason, it is possible to perform simple control that maintains the state before the fluctuation of the power supplied by the first resonance means, and it is possible to easily control the magnitude of the power supplied by the first resonance means.

In the present invention, the control means controls the magnitude of electric power supplied by the first resonance means based on the following expression 1. Expression 1: VRn = (1 / ((1-Y) e ^{-x / p} + Y) ^1/2 ) × VR1
VRn: power ratio supplied from the first resonance means after correction
VR1: Power ratio supplied from the first resonance means before correction
x: Power ratio supplied from the second resonance means
Y: Load resistance of the first resonance means when supplying from the second resonance means at the standard maximum power value (VR2max)
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)
A configuration is preferable. In the present invention, the magnitude of the power supplied by the first resonance means is controlled by performing arithmetic processing based on Equation 1, so that the fluctuation amount of the power supplied by the first resonance means is set to an appropriate magnitude of power. Control can be performed only by calculation, and control of the magnitude of power supplied by the first resonance means can be facilitated. Furthermore, even when the shape of the object to be heated, the induction heating conditions, and the like are different, the control can be performed using Expression 1, and versatility can be improved.

  Furthermore, in the present invention, the first resonance means includes first oscillation means that converts supplied DC power into AC power having a predetermined frequency and supplies the AC power to the induction heating coil, and the second resonance means. The means comprises second oscillating means for converting the supplied DC power into AC power having a frequency lower than the frequency converted by the first oscillating means, and supplying the AC power to the induction heating coil. Fluctuations in DC power supplied to the first oscillating means are detected by supplying power by superimposing the frequency by the second resonant means on the frequency of power supplied from the first resonant means, It is preferable to control the magnitude of the power supplied by the first resonance means so that the frequency is superposed by the two resonance means and maintained at the DC power immediately before the power is supplied. In the present invention, the control means converts the DC power supplied to AC power having a predetermined frequency and changes the DC power supplied to the first oscillation means in the first resonance means supplied to the induction heating coil. Detect and convert the DC power supplied by the second oscillating means in the second resonance means to AC power having a frequency lower than the frequency converted by the first oscillating means and superimpose the frequency to supply to the induction heating coil Control is performed to maintain the state of DC power supplied to the first oscillating means immediately before the start. For this reason, the control maintained in the power state supplied by the first resonance means before the power is supplied in a state where the frequency is superimposed can be easily obtained by simple control.

The induction heating device of the present invention includes an induction heating coil that induction-heats an object to be heated, and first resonance means that supplies electric power of a predetermined frequency to the induction heating coil to inductively heat the object to be heated. A second resonance unit for supplying power to the induction heating coil at a frequency lower than that of the first resonance unit to inductively heat the object to be heated; and a primary side connected to the first resonance unit. The induction heating is performed by superimposing a transformer having a secondary side connected to the second resonance means, a frequency of power supplied by the first resonance means, and a frequency of power supplied by the second resonance means. Control means for controlling the first resonance means and the second resonance means so that electric power can be supplied to the coil, and for controlling the magnitude of the electric power supplied by the first resonance means based on the following equation 1 When,
Formula 1: VRn = (1 / ((1-Y) e- ^{x / p} + Y) ^1/2 ) * VR1
VRn: power ratio supplied from the first resonance means after correction
VR1: Power ratio supplied from the first resonance means before correction
x: Power ratio supplied from the second resonance means
Y: Load resistance of the first resonance means when supplying from the second resonance means at the standard maximum power value (VR2max)
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)
It is characterized by comprising.

  In the present invention, the control means supplies the power of a predetermined frequency to the induction heating coil connected to the primary side of the transformer and induction-heats the object to be heated, and causes the object to be heated to be inductively heated. The second resonance means connected to the secondary side of the transformer and having a frequency lower than the frequency of the first resonance means is supplied to the induction heating coil to inductively heat the object to be heated. Based on the above, the magnitude of the electric power supplied by the first resonance means is controlled. For this reason, by supplying electric power from the first resonance means and the second resonance means in a state where different frequencies are superimposed, the impedance in the first resonance means that fluctuates in response to fluctuations in the permeability of the object to be heated. Even in a state in which the power to be supplied changes due to fluctuations in power, the amount of power changed by the control means is controlled and supplied according to the calculation based on Equation 1, so that high-frequency power can be stably supplied with a simple configuration, Induction heating efficiency is obtained.

  Furthermore, the induction heating apparatus of the present invention includes an induction heating coil that induction-heats an object to be heated, and first oscillation means that converts supplied DC power into AC power having a predetermined frequency. Is supplied to the induction heating coil to inductively heat the object to be heated, and the supplied DC power is converted to AC power having a frequency lower than the frequency converted by the first oscillation means. 2 oscillating means, a second resonance means for supplying the converted AC power to the induction heating coil to inductively heat the object to be heated, and a primary side connected to the first resonance means. A transformer having a secondary side connected to the two resonance means, and the frequency of the AC power supplied by the first resonance means to the DC power supplied to the first oscillation means and the second oscillation means, Provided by the second resonance means And superimposing the frequency of the alternating current power on the induction heating coil so that the alternating current power can be supplied to the induction heating coil, the direct current power supplied to the first oscillation means is superimposed on the frequency by the second resonance means. And control means for controlling to maintain the DC power immediately before the AC power is supplied.

  In this invention, the control means converts the DC power connected to the primary side of the transformer and supplied from the first oscillating means into AC power having a predetermined frequency to induce induction heating of the object to be heated. A first resonance means for supplying and heating an object to be heated by induction; and an induction heating coil for supplying electric power having a frequency lower than a frequency connected to the secondary side of the transformer and converted by the first oscillation means by the second oscillation means. The first resonance means immediately before supplying the AC power from the second resonance means by controlling the DC power supplied to the second resonance means for inductively heating the object to be heated by supplying the frequency to the second resonance means The DC power supplied to the first oscillation means is maintained. For this reason, by supplying electric power from the first resonance means and the second resonance means in a state where different frequencies are superimposed, the impedance in the first resonance means that fluctuates in response to fluctuations in the permeability of the object to be heated. Even in a state where the power to be supplied changes due to fluctuations in power, the power that is changed by the control means is controlled by the DC power before being converted into AC power, and the AC power is supplied. Electric power can be supplied, and good induction heating efficiency can be obtained.

  In the present invention, the first resonance means is connected in series to the primary side of the transformer on the output side of the first oscillation means to compensate for reactive power of the transformer and the induction heating coil. And a capacitor for attenuating a frequency component fed back from the second resonance means by the transformer, and the second resonance means is connected to the secondary side of the transformer on the output side of the second oscillation means. It is preferable to include a capacitor that is connected in series and suppresses frequency feedback from the first resonance means and compensates for reactive power of the transformer and the induction heating coil. In the present invention, a capacitor is connected in series to the primary side of the transformer whose primary side is connected to the first oscillating means of the first resonance means to compensate for the reactive power of the transformer and the induction heating coil and The frequency component fed back from the second resonance means for supplying a low frequency is attenuated by the amplifier. Further, the capacitor of the second resonance means is directly connected in series with the secondary side of the transformer to suppress the feedback of the frequency from the first resonance means and to compensate the reactive power of the transformer and the induction heating coil. . For this reason, by setting the secondary side of the transformer to a low inductance, a low impedance is obtained for the lower frequency current supplied by the second resonance means, so that the lower frequency current is bypassed. The object to be heated is efficiently heated by the induction heating coil with the lower frequency of the resonance means of 2. Further, since the capacitor of the second resonance means compensates for the reactive power of the transformer having a low inductance, it is easy to set a low impedance for the current of the higher frequency of the first resonance means. The capacitor of the resonance means bypasses the current of the higher frequency, and the induction heating coil is efficiently heated by the higher frequency of the first resonance means. And since the secondary side of the transformer functions as a reactor for preventing the high-frequency feedback of the first resonance means, the second resonance means is used for preventing the high-frequency feedback of the first resonance means. There is no need to provide a reactor or the like, and the configuration is simplified.

  Further, in the present invention, the second resonance means is such that the second oscillation means is a voltage type, and is connected in series to the output side of the second oscillation means and the secondary side of the transformer. It is preferable to provide a reactor that attenuates the feedback of the frequency of the resonance means. In this invention, since the reactor for attenuating the feedback of the frequency of the first resonance means is connected in series with the output side of the voltage-type second oscillation means and the secondary side of the transformer in the second resonance means, With a simple configuration in which a relatively small reactor that attenuates frequency feedback is provided, the second oscillation means can be easily configured to convert, for example, an AC power source to a DC power source and then to an AC power source of a predetermined frequency. The voltage form can be used.

  And the induction heating method of the present invention is an induction heating method in which the induction heating coil for induction heating the object to be heated is supplied with electric power of different frequencies from a plurality of resonance means to induction heating the object to be heated, The resonance that supplies high frequency power in accordance with the rate at which the magnetic permeability of the object to be heated changes by superimposing at least two frequencies of power supplied from the resonance means to the induction heating coil. Controlling the magnitude of power supplied by the means.

  In the present invention, the induction heating coil for induction heating the object to be heated is supplied with electric power of different frequencies to superimpose at least two different frequencies from a plurality of resonance means for induction heating of the object to be heated. Is controlled in accordance with the rate at which the permeability of the object to be heated changes. For this reason, by supplying power from a plurality of resonance means in a state where different frequencies are superimposed, the permeability of the resonance means for supplying power at a particularly high frequency varies due to fluctuations in the magnetic permeability of the object to be heated. The amount of power fluctuation is appropriately controlled, high-frequency AC power can be stably supplied, and good induction heating efficiency can be obtained.

  Further, the induction heating method of the present invention is an induction heating method in which the induction heating coil for induction heating the object to be heated is supplied with electric power of different frequencies from a plurality of resonance means to induction heat the object to be heated, The high frequency corresponding to the impedance fluctuation state of the resonance means for supplying high frequency power by superimposing at least two frequencies of power supplied from the resonance means to supply power to the induction heating coil. Controlling the magnitude of the power supplied by the resonance means for supplying the power.

  In the present invention, the induction heating coil for induction heating the object to be heated is supplied with electric power of different frequencies to superimpose at least two different frequencies from a plurality of resonance means for induction heating of the object to be heated. The magnitude of the power supplied by the resonance means for supplying the high frequency power is controlled in accordance with the fluctuation state of the impedance of the resonance means for supplying the high frequency power. For this reason, by supplying power from a plurality of resonance means in a state where different frequencies are superimposed, fluctuations in impedance in the resonance means that supplies power at a particularly high frequency that varies in accordance with fluctuations in the permeability of the object to be heated. Therefore, it is possible to appropriately control the amount of fluctuation of electric power, stably supply high-frequency AC power, and obtain good induction heating efficiency.

Furthermore, the induction heating method of the present invention is an induction heating method of inductively heating the object to be heated by supplying electric power of different frequencies from a plurality of resonance means to an induction heating coil for induction heating of the object to be heated, When supplying power to the induction heating coil by superimposing at least two frequencies of the power supplied from the resonance means, the power supplied by the resonance means that supplies high frequency power based on the following equation 1 Equation 1: VRn = (1 / ((1-Y) e- ^{x / p} + Y) ^1/2 ) * VR1
VRn: power ratio supplied from the high frequency side resonance means after correction
VR1: Ratio of power supplied from resonance means on the high frequency side before correction
x: Ratio of power supplied from resonance means on the lower frequency side
Y: Load resistance of the first resonance means when supplying the standard maximum power value (VR2max) from the resonance means on the low frequency side
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)
It is characterized by that.

  In the present invention, the induction heating coil for induction heating the object to be heated is supplied with electric power of different frequencies to superimpose at least two different frequencies from a plurality of resonance means for induction heating of the object to be heated. The magnitude of the electric power supplied by the resonance means for supplying the high frequency electric power is controlled based on the equation (1). For this reason, by supplying power from a plurality of resonance means in a state where different frequencies are superimposed, due to impedance fluctuations in the resonance means for supplying high frequency power that fluctuates in response to fluctuations in the permeability of the object to be heated. Even when the power to be supplied is changed, the amount of power changed by the control means is controlled and supplied according to the calculation based on Equation 1, so that high-frequency power can be stably supplied with a simple configuration, and the induction heating efficiency is good. Is obtained.

  Also, the induction heating method of the present invention induces the object to be heated by supplying each of the objects to be heated to an induction heating coil for induction heating of the object to be heated from a plurality of resonance means that respectively convert DC power into AC power having a predetermined different frequency. An induction heating method for heating, wherein the resonance means supplies high frequency AC power when supplying AC power to the induction heating coil by superimposing at least two frequencies of AC power supplied from the resonance means. The DC power supplied to is controlled to be maintained at the DC power immediately before the AC power is supplied by the resonance means that supplies the AC power with a low frequency in a superimposed manner.

  In this invention, at least two different frequencies are superimposed on the induction heating coil by superimposing at least two different frequencies on the induction heating coil for induction heating the object to be heated by converting the DC power into AC power of different frequencies and supplying them respectively. When supplying AC power, the DC power supplied to the resonance means for supplying high frequency AC power is changed to the DC power immediately before the AC power is supplied by the resonance means for supplying low frequency AC power in a superimposed manner. Control to maintain state. For this reason, by supplying power from a plurality of resonance means in a state where different frequencies are superimposed, fluctuations in impedance in the resonance means that supplies high-frequency AC power that fluctuates in response to fluctuations in the permeability of the object to be heated. Even when the power supplied by the power supply changes, the AC power is supplied by controlling the changing power supply with the DC power before conversion to AC power, so high-frequency power can be supplied stably with a simple configuration. Good induction heating efficiency can be obtained.

  Hereinafter, an induction heating apparatus according to an embodiment of the present invention will be described with reference to the drawings. In addition, although the induction heating apparatus in this Embodiment demonstrates the structure which carries out an induction heating process of the to-be-heated object, for example using two different frequencies, as a different frequency, not only two types but a several frequency is demonstrated. You may superimpose. In addition, the object to be heated has a complicated shape having a plurality of irregularities on the surface, such as gears, screws, bolts, nuts, cylindrical members such as shafts, composite materials in which different materials are laminated, etc. Can be targeted. FIG. 1 is a circuit diagram showing a schematic configuration of the induction heating apparatus in the present embodiment.

[Configuration of induction heating device]
In FIG. 1, reference numeral 100 denotes an induction heating device, and this induction heating device 100 uses two different frequencies to induction-harden an object to be heated 101 having an uneven surface to be heated, such as a gear, for example. It is. The induction heating apparatus 100 includes an induction heating coil 110 that induction-heats an object to be heated 101, a first transformer 120 as a transformer, and a predetermined frequency, for example, a frequency of 50 kHz to 1 MHz. First resonance means 130 for supplying high-frequency power to induction heating, and heating by supplying to induction heating coil 110 a medium frequency power lower than the frequency of first resonance means 130, for example, 1 kHz to 50 kHz. Second resonance means 140 to be controlled, and control means 150 are provided.

  The induction heating coil 110 is connected in series to the first resonance means 130 and the second resonance means 140. The induction heating coil 110 is supplied with high-frequency AC power from the first resonance means 130 and medium-frequency AC power from the second resonance means 140, and induction-heats the article to be heated 101.

  The first transformer 120 is connected to the first resonance means 130 and the second resonance means 140 and is connected to the induction heating coil 110, and supplies AC power having a predetermined frequency to the induction heating coil 110. The first transformer 120 has, for example, a small self-inductance, that is, an air-core coupling type, and the secondary winding 122 and the tertiary winding 123 on the secondary side are wound once. The inductance values of the winding 122 and the tertiary winding 123 and the inductance value of the induction heating coil 110 are set to be substantially the same. In the first transformer 120, the induction heating coil 110 is connected between one end side of the secondary winding 122 and the other end side of the tertiary winding 123.

  The first resonance unit 130 includes a first oscillation unit 131, a second transformer 132, and a first capacitor C1. The first oscillation means 131 includes a first converter 131A, a first smoothing capacitor Cf1, and a first inverter 131B. The first converter 131A is a forward conversion circuit using, for example, various bridge rectifier circuits, and is connected to the commercial AC power source e to convert the AC power of the commercial AC power source e into DC power. The converted DC power is appropriately smoothed through the first smoothing capacitor Cf1 and output to the first inverter 131B. The first inverter 131B is a voltage source inverter, for example, and converts the DC power input through the first smoothing capacitor Cf1 into the above-described high-frequency AC power having a predetermined frequency. The primary winding 132A of the second transformer 132 is connected in series between the output terminals of the first inverter 131B.

  The first resonance means 130 includes a series circuit of the first capacitor C1 and the primary winding 121 of the first transformer 120 between the output terminals of the secondary winding 132B of the second transformer 132. It is configured to be connected in series. That is, the first capacitor C1 enters a series resonance state by a predetermined high-frequency AC power output from the first inverter 131B and supplied via the second transformer 132, and the induction heating coil 110 is heated. 101 is induction-heated. The first capacitor C1 compensates for the reactive power of the first transformer 120 and the induction heating coil 110, and also has a medium frequency of AC power fed back from the second resonance means 140 by the first transformer 120. Attenuates the component. Then, as described above, the first resonance means 130 supplies high-frequency AC power having a frequency of 50 kHz to 1 MHz to the induction heating coil 110 via the first transformer 120, and the first capacitor C 1 The object to be heated 101 is induction-heated by series resonance. Here, when the frequency is lower than 50 kHz, there is a possibility that good quenching of the heated object 101 whose surface to be heated, particularly the gear, is uneven cannot be obtained. On the other hand, if it is higher than 1 MHz, it is difficult to obtain good induction heating. For this reason, it is preferable to set the frequency supplied by the first resonance means 130 in the range of 50 kHz to 1 MHz.

  The second resonance unit 140 includes a second oscillation unit 141, a reactor L1, a second capacitor C2, a third transformer 142, a third capacitor C3, and a fourth capacitor C4. I have. Similarly to the first resonance means 130, the second oscillation means 141 includes a second converter 141A, a second smoothing capacitor Cf2, and a second inverter 141B. The second converter 141A is a forward conversion circuit using various bridge rectifier circuits, for example, and is connected to the commercial AC power source e to convert the AC power of the commercial AC power source e into DC power. The converted DC power is appropriately smoothed through the second smoothing capacitor Cf2 and output to the second inverter 141B. The second inverter 141B is, for example, a voltage source inverter, and converts the DC power input through the second smoothing capacitor Cf2 into the above-described medium frequency AC power having a predetermined frequency.

  In the second resonance means 140, a series circuit of the reactor L1, the second capacitor C2, and the primary winding 142A of the third transformer 142 is connected between the output terminals of the second inverter 141B. Has been. In the second resonance means 140, a series circuit of a third capacitor C3 and a fourth capacitor C4 is connected between the secondary windings 142B of the third transformer 142. The connection point between the third capacitor C3 and the fourth capacitor C4 is connected to the ground. Further, in the second resonance means 140, the output terminal of the secondary winding 142B of the third transformer 142 is connected to the other end of the secondary winding 122 of the first transformer 120 and one of the tertiary windings 123. It is connected. In the second resonance means 140, the reactor L1 attenuates the high-frequency feedback component of the first resonance means 130, thereby forming a series resonance circuit. In addition, the third capacitor C3 and the fourth capacitor C4 generate reactive power of the first transformer 120 in which the secondary side of the first transformer 120 has a low inductance in order to bypass the medium-frequency alternating current. To compensate. Then, as described above, the second resonance means 140 supplies medium frequency AC power having a frequency of 1 kHz or more and 50 kHz or less to the induction heating coil 110, and the series resonance of the reactor L1 and the second capacitor C2 causes the resonance. The heated object 101 is induction-heated. Here, when the frequency is lower than 1 kHz, it may be difficult to obtain good induction heating. On the other hand, when it becomes higher than 50 kHz, there is a possibility that good induction heating over the inside of the article to be heated 101 cannot be obtained. Therefore, the frequency supplied by the second resonance unit 140 is preferably 1 kHz or more and 50 kHz or less.

  The control unit 150 controls the operations of the first resonance unit 130 and the second resonance unit 140. The control means 150 includes operation means (not shown) for setting the magnitude of the AC power supplied from the first resonance means 130 and the second resonance means 140 to the induction heating coil 110 by an input operation by an operator. Yes. Specifically, the operation means includes an operation means having an operation knob that can be input by an operator, for example, and the maximum output of the first resonance means 130 and the second resonance means 140 is 100%, and 0%. When the operation knob is input within the range of 100% or less, the first resonance unit 130 and the second resonance unit 140 are controlled to have a current value corresponding to the set value that is input by the constant current control. Set and input each AC power. Then, the control means 150 causes the first resonance means 130 to supply predetermined high-frequency AC power to the induction heating coil 110 under constant current control so that the current value becomes constant at the set output ratio. Further, the control means 150 supplies the induction heating coil 110 with AC power of a predetermined medium frequency by the second resonance means 140 and AC power of the output ratio set by the constant current control. These high-frequency AC power and medium-frequency AC power can be supplied independently, and can be supplied in a state where the high-frequency and medium-frequency are appropriately superimposed. Then, when supplying the AC power in a state where the high frequency and the medium frequency are superimposed, the control unit 150 corrects the set value of the first resonance unit 130 based on the following formula 1, and generates a constant AC power. Control the supply state. Since the current control is constant, the set value and the supplied current value are directly proportional to each other. For example, when the maximum standard value is 10000 A, if the set value is 9%, it is about 900 A, and if it is 50%. If it is about 5000A, 100%, it will be about 10000A.

  That is, the control unit 150 includes a conversion value acquisition unit (not shown), a processing unit, and the like as programs. The conversion value acquisition means supplies the AC power from the first resonance means 130 and the second resonance means 140 in a state in which different high and medium frequencies are superimposed, so that the permeability of the article to be heated 101 changes. Corresponding to the changing magnetic permeability, the impedance of the first resonance means 130 on the higher frequency side is reduced, and the AC power supplied from the first resonance means 130 is reduced. As a result, the conversion value acquisition unit calculates a correction value as a conversion value for correcting the power to be reduced to a state before superimposition based on Equation 1. That is, since the set value and the current value are directly proportional, the correction value is calculated using a linear function. Note that Formula 1 is appropriately stored in a storage unit such as a memory (not shown) configured in the control unit 150, for example. In the present embodiment, a configuration for calculating a corrected set value, which is a correction value for correcting the set value, as the conversion value will be described. However, the conversion value is not limited to this, and for example, the heating object 101 Read conversion values set in advance in a matrix based on the shape, material, induction heating conditions, etc., or calculate based on the formula set in more detail from Formula 1 for each shape, material, etc. of the object to be heated 101 Specifically, when the set value and the current value have a functional relationship such as a quadratic order or an exponent that is not directly proportional, the calculation may be performed based on the function. As a configuration for storing, any method such as storing in the control unit 150 from a recording medium in which a formula or a conversion value is recorded in advance, or setting and storing in the control unit 150 by an input operation by the operation unit is available. Available. Then, based on the correction value calculated by the conversion value acquisition means, the processing means controls the first resonance means 130 to supply AC power having a current value according to the converted corrected setting.

(Formula 1)
VRn = (1 / ((1-Y) e- ^{x / p} + Y) ^1/2 ) * VR1
VRn: power ratio supplied from the high frequency side resonance means after correction
(That is, the set value in the first resonance means 130 after correction)
VR1: Ratio of power supplied from resonance means on the high frequency side before correction
(That is, the set value in the first resonance means 130 before correction)
x: Ratio of power supplied from resonance means on the lower frequency side
(That is, the set value (= VR2) in the second resonance means 140)
Y: Load resistance of the first resonance means 130 when supplying the standard maximum power value (standard maximum setting value: VR2max) from the low frequency side resonance means (second resonance means 140)
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)

[Operation of induction heating device]
(Induction heat treatment)
Next, the operation of the induction heating process will be described as the operation of the induction heating apparatus 100 in the above-described embodiment.

  When high-frequency AC power converted by the first oscillation means 131 in the first resonance means 130 is output by the control means 150 based on a set value set in advance corresponding to the state of induction heating, the first One capacitor C1 enters a series resonance state, is supplied to the induction heating coil 110 via the first transformer 120, and the object to be heated 101 is induction-heated by the induction heating coil 110. When supplying high-frequency AC power to the induction heating coil 110, in the second resonance means 140, the reactor L1 attenuates the high-frequency feedback component of the first resonance means 130, and the third capacitor C3 and The fourth capacitor C4 compensates for the reactive power of the first transformer 120.

  Further, the control means 150 outputs the medium frequency AC power converted by the second oscillation means 141 in the second resonance means 140 based on the set value set in advance corresponding to the state of induction heating. And the reactor L1 and the second capacitor C2 enter a series resonance state, bypass the secondary winding 122 and the tertiary winding 123 of the first transformer 120, and are supplied to the induction heating coil 110. The object to be heated 101 is induction-heated by 110. When the medium frequency AC power is supplied to the induction heating coil 110, the first capacitor C1 attenuates the medium frequency feedback, and the secondary winding 122 and the tertiary winding 123 of the first transformer 120 are attenuated. The intermediate frequency AC power is supplied to the induction heating coil 110.

  Here, when high-frequency and medium-frequency AC power is supplied in a state where the high-frequency and medium-frequency are superimposed, the permeability of the object to be heated 101 increases as the current value of the supplied medium-frequency AC power increases. With the change, the impedance of the AC power in the first resonance means 130 on the high frequency side decreases. As a result, the control unit 150 performs correction control to compensate for the decrease in the current value of the supplied AC power due to the decrease in impedance in the first resonance unit 130 based on the above-described equation 1. Specifically, the converted value acquisition unit of the control unit 150 calculates the corrected set value VRn from the set value VR1 set by the operator using the operation unit, based on Expression 1 stored in the storage unit. . In a state where AC power is supplied from the first resonance unit 130 with the calculated set value VRn after correction, the first resonance unit 130 is controlled by the processing unit of the control unit 150, and the AC power is output in a state where the frequency is superimposed. AC power having the same magnitude as that in the state of being supplied immediately before supplying is supplied.

(Correction value)
Here, Equation 1 described above for correcting a decrease in the power supplied from the first resonance means 130 will be described below with reference to the drawings. FIG. 2 is a circuit diagram showing an experimental apparatus for setting a control method for controlling the magnitude of power supplied by the first resonance means on the high frequency side in the present invention. FIG. 3 is a timing chart for explaining the timing for measuring the voltage value and the current value in the first resonance means according to the supply conditions of AC power of different frequencies. FIG. 3A shows the supply status of AC power in the first resonance means. (B) is a waveform diagram showing the AC power supply status in the second resonance means. FIG. 4 is a graph showing the rate of change of impedance in the first resonance means with respect to the magnitude of the medium frequency bias current when the AC power is supplied with the frequency superimposed by the second resonance means.

  First, an experiment was conducted to recognize the situation where the impedance on the high frequency side is lowered when AC power is supplied with the frequency superimposed. As an experimental apparatus, an induction heating apparatus 200 having the configuration shown in FIG. 2 was used. In addition, about the structure same as the induction heating apparatus 100 shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  Inductive heating apparatus 200 shown in FIG. 2 replaces voltage-type series resonance type second resonance means 140 in induction heating apparatus 100 shown in FIG. 1 described above, with current-type parallel resonance type second resonance means 240 and It is a thing. That is, the induction heating apparatus 200 includes an induction heating coil 110, a first transformer 120 as a transformer, a first resonance means 130 having a voltage type series resonance type on the high frequency side, and a current type parallel resonance type on the medium frequency side. Second resonance means 240 and the like. The induction heating coil 110 has, for example, an inner diameter of 135.0 mm, a width dimension of 140.0 mm, and a number of turns of one. The first transformer 120 has a small self-inductance, for example, an air-core coupled type, and the secondary winding 122 on the secondary side is a single turn, as in the first transformer 120. It is set to be approximately the same as the inductance value of the induction heating coil 110. Similar to the induction heating apparatus 100, the first resonance unit 130 is connected between the output terminal of the first inverter 131 B in the first oscillation unit 131 and the primary winding of the first capacitor C 1 and the first transformer 120. A series circuit of lines 121 is connected. The first capacitor C1 is in a series resonance state by a predetermined high-frequency AC power with a predetermined voltage output from the first inverter 131B, and the induction heating coil 110 causes the object to be heated. 101 is induction-heated. The first capacitor C1 compensates for the reactive power of the first transformer 120 and the induction heating coil 110, and the medium frequency component of the AC power fed back from the second resonance means 240 by the first transformer 120. Attenuate.

  The second resonance means 240 includes a second oscillation means 241 including a second converter 141A, a second reactor Lf2, and a second inverter 241B, and a third capacitor C3. Similarly to the first converter 131A, the second converter 141A of the second oscillating means 241 is a forward conversion circuit and is connected to the commercial AC power source e to convert AC power from the commercial AC power source e into DC power. The output is output to the second inverter 241B through the second reactor Lf2 so that the direct current does not change suddenly. The second inverter 241B is, for example, a current source inverter, and converts DC power input via the second reactor Lf2 into medium frequency AC power, which is a predetermined frequency, and outputs it. The third capacitor C3 is connected in parallel to the secondary winding 122 of the first transformer 120 in parallel with the induction heating coil 110, and is in a parallel resonance state by the medium frequency AC power output from the second inverter 241B. Thus, the object to be heated 101 is induction-heated by the induction heating coil 110. The third capacitor C3 is set to an impedance sufficiently small for the high-frequency current of the first resonance means 130, and compensates for the reactive power of the first transformer 120 and the induction heating coil 110. That is, the second capacitor C3 includes a reactive power of the first transformer 120 in which the inductance is set to be small, and a reactive power of the induction heating coil 110 in which the inductance of the first transformer 120 is set to be substantially the same. Is set to a level that compensates for the high-frequency alternating current, and is set to a low impedance for a high-frequency alternating current. Further, the third capacitor C3 suppresses high-frequency feedback from the first resonance means 130.

  In the induction heating apparatus 200, when high-frequency AC power is output from the first oscillation means 131 of the first resonance means 130, the first capacitor C1 enters the series resonance state, and the first transformer 120 It is converted into a predetermined voltage and supplied from the secondary winding 122 to the induction heating coil 110. When the high frequency is supplied to the induction heating coil 110, since the impedance of the third capacitor C3 of the second resonance unit 240 is set to be sufficiently small, the high frequency current is bypassed and the high frequency is induced by the induction heating coil. 110 is efficiently supplied, and the object to be heated 101 is induction-heated by the induction heating coil 110. The third capacitor C3 of the second resonance unit 240 suppresses high-frequency feedback from the first resonance unit 130, and prevents damage to the second resonance unit 240 due to high-frequency feedback. When medium frequency AC power is output from the second oscillating means 241, the third capacitor C3 enters a parallel resonance state, and medium frequency AC power is supplied to the induction heating coil 110, so that the object to be heated 101 is heated. Induction heating. When the intermediate frequency is supplied, since the secondary winding 122 of the first transformer 120 has a low inductance, the impedance becomes low for the intermediate frequency AC current. Therefore, the secondary winding of the first transformer 120 is low. 122 becomes a bypass of the medium frequency alternating current, and the medium frequency is efficiently supplied to the induction heating coil 110. The first capacitor C1 of the first resonance means 130 attenuates the medium frequency feedback from the second resonance means 240 by the first transformer 120, and the first resonance means 130 by the medium frequency feedback is attenuated. Damage is prevented.

  Using this induction heating apparatus 200, induction heating was performed, and an experiment for measuring the supply status of AC power was performed. As the object to be heated 101, a steel pipe having an outer shape of 115.0 mm was used. In the induction heating apparatus 200, the first oscillation means 131 in the first resonance means 130 is set to a frequency of 212 kHz with an output of 200 kW, and the second oscillation means 241 of the second resonance means 240 is set to a frequency of 12 kHz with an output of 200 kW. . In the induction heating process, first, the first resonance means 130 performs constant current control for supplying high-frequency AC power having a set value of 40%, an AC current of 180 A, and a frequency of 212 kHz to the induction heating coil 110. The voltage is constant in a state in which AC power of medium frequency is superimposed on the induction heating coil 110 with high frequency by the output of each set value from the second resonance means 240 in a state where the AC power supplied by induction heating of the heated object 101 is stable. The steel tube was induction-heated until the voltage was stabilized by control. The supply state of AC power in the first resonance means 130 is measured at four timings immediately before and immediately after the start of supply of the intermediate frequency and immediately before and immediately after the stop of supply of the intermediate frequency, that is, in FIG. The voltage value and current value were measured at the timings of the measurement points A, B, C, and D shown. Then, the impedance was calculated based on the voltage value and the current value, and the change state of the impedance in the first resonance means 130 was confirmed. The results are shown in Table 1, Table 2 and FIG.

  From the results shown in Tables 1 and 2 and FIG. 4, the ratio of the change in impedance in the first resonance means 130 before and after the start of supply of the medium frequency and before and after the stop of supply (ZB / ZA and ZC / ZD) is almost equal, and the influence of temperature due to induction heating of the article to be heated 101 is not so much recognized. Since the first resonance unit 130 performs constant current control by superimposing and supplying the medium frequency, as the bias current value of the AC power supplied from the second resonance unit 240 increases, It was recognized that the voltage value of the high-frequency AC power supplied from the first resonance means 130 was lowered, that is, the impedance in the first resonance means 130 was lowered. That is, by supplying alternating power to the induction heating coil 110 while superimposing different frequencies, it is considered that the magnetic permeability of the article to be heated 101 is reduced and the impedance on the high frequency side is particularly reduced. Therefore, since the high frequency output from the first resonance means 130 is reduced, the high frequency supplied from the first resonance means 130 is necessary in order to obtain the desired quenching on the surface of the object 101 to be heated by the high frequency. Is required to be maintained in a state immediately before the medium-frequency AC power is supplied from the second resonance means 240. That is, in the case where AC power is supplied in a state where the frequency is superimposed, it is necessary to compensate for the decrease in the required high-frequency coil current due to a decrease in impedance on the high-frequency side in response to a change in permeability. Become.

  Specifically, in high-frequency independent operation in which AC power is supplied only from the first resonance means 130, when the set value VR1 of the first resonance means 130 is 40%, as shown in Table 1, the AC power The voltage value Vdc is about 193 V, the current value Idc is 180 A, and the power value Pdc is about 34.7 kW (= 193 [V] × 180 [A]). When the conversion coefficient between the direct current impedance and the inverse converter output impedance in the first resonance means 130 of the induction heating device 200 is 0.8, the impedance Z of the induction heating coil 110 viewed from the first resonance means 130 is 0.8 × Zdc = 0.8 × (193/180) ≈0.86 [Ω].

  On the other hand, in the state in which the intermediate frequency is superimposed on the high frequency and the AC power is supplied, when the set value VR2 of the second resonance means 240 is 70%, the voltage value Vdc of the AC power from the first resonance means 130 is At 115 V, the current value Idc is 180 A, and the power value Pdc is about 20.7 kW (= 115 [V] × 180 [A]). Therefore, the impedance Z of the induction heating coil 110 viewed from the first resonance means 130 is 0.8 × Zdc = 0.8 × (115/180) = 0.51 [Ω]. For this reason, the reduction ratio of the impedance is 0.51 / 0.86≈0.59. That is, the electric power to be input is also 20.7 / 34.7≈0.6, which is a reduction of 60%.

  As described above, constant current control is performed in a voltage form in which the set value and the current value are in direct proportion. For this reason, since the supplemented current value substantially corresponds to the set value, the set value may be corrected in accordance with the reduction ratio of the impedance. In other words, the set value can be corrected by the reciprocal of the rate of decrease in impedance using Equation 2 shown below.

(Formula 2)
VRn = K × VR1
VRn: set value in the first resonance means after correction VR1: set value in the first resonance means before correction
K: Correction constant

  Here, since the set value in the first resonance means 130 is a current, it has a square relationship with the AC power. As a result, the correction constant K is expressed by Equation 3 shown below.

(Formula 3)
K = (1 / y) ^1/2
y: Impedance reduction rate

  And when the coil current in the induction heating coil 110 in which the set value of the second resonance means 240 was about 35% increased from 3600 A, the impedance was almost stable. That is, as can be seen from the graph shape of FIG. 4, the impedance reduction rate is stabilized at a certain middle frequency bias current value, and has an approximately exponential relationship. Therefore, the reduction ratio y of the impedance is expressed by the following equation 4.

(Formula 4)
y = (1-Y) e- ^{x / p} + Y
x: Set value in the second resonance means (= VR2)
(That is, 0 ≦ VR1 ≦ 1)
Y: Impedance reduction ratio (ZB / ZA) in the first resonance means at the maximum set value (VR2max) in the second resonance means
(In other words, a decrease in which the impedance in the first resonance means is stabilized)
p: damping constant

  Here, in order to reduce the error so that desired quenching can be obtained, the error with respect to the asymptotic line where the impedance in the first resonance means 130 is stable at the maximum set value in the second resonance means 240 is reduced to 1% or less. Set. That is, the attenuation constant p is expressed by Equation 5 shown below.

(Formula 5)
p = VR2max / ABS {ln (1%)}
= 1 / 4.6
= 0.217
ABS {m}: absolute value of m

  Based on these formulas 2 to 5, the relational expression for calculating the correction value for correcting the reduction of the high frequency impedance in the state where the frequency is superimposed is expressed by the above-described formula 1. That is, the correction value obtained by correcting the set value to compensate for the decrease in impedance is calculated based on Equation 1.

  In the process of contour quenching the steel pipe in the induction heating apparatus 200 described above using Equation 1, that is, quenching with a predetermined thickness from the outer surface, a correction value is calculated as shown in Equation 6 below.

(Formula 6)
VRn = (1 / ((1-Y) e- ^{x / p} + Y) ^1/2 ) * VR1
= (1 / ((1-0.59) e ^{(-70 / 21.7)} +0.59) ^1/2 ) × 0.40
= 1.285 x 0.40
= 0.514

  On the other hand, when the operation is performed with a new set value which is the obtained correction value, the voltage value Vdc of the AC power from the first resonance means 130 is 115 [V] × 1.285 = 148 [V], and the current value. Idc is 180 [A] × 1.285 = 131 [A], and the power value Pdc is 34.2 kW (= 148 [V] × 231 [A]). Then, it can be seen that during the single operation in which AC power is supplied only from the first resonance means 130, that is, at the measurement point A, as described above, since it is 34.7 kW, the values are almost the same and can be corrected satisfactorily. The corrected impedance is 0.8 × (148 [V] / 231 [A]) = 0.51 [Ω], which is the same as the impedance obtained by superimposing and supplying the frequency at the measurement point B. However, the power value is 34.2 kW. From this, the control by the control means 150 compensates for the decrease in high-frequency impedance caused by superimposing and supplying the frequency, and induction heating at the measurement point A immediately before supplying AC power with the frequency superimposed. Induction heating can be performed in the same state.

  As a result of a similar experiment under the condition that the gear to be contour-quenched in place of the steel pipe as the article to be heated 101, it is recognized that the rate of change in impedance in the first resonance means 130 also decreases substantially exponentially. It was.

[Effects of induction heating device]
As described above, in the above-described embodiment, the first resonance unit 130 and the second resonance units 140 and 240 that supply power of different frequencies to the induction heating coil 110 that induction-heats the object 101 to be heated are supplied. By supplying alternating power to the induction heating coil 110 by superimposing at least two different frequencies of alternating current power, ie, high frequency and medium frequency, the conversion value acquisition means of the control means 150 allows the change of the object to be heated 101 to be changed. A correction value is acquired for maintaining the power state that is supplied immediately before the supply with the frequency superimposed by the first resonance means 130 that supplies the high frequency power corresponding to the magnetic permeability. That is, the electric power supplied from the first resonance means 130 that calculates and supplies high-frequency AC power based on the calculated correction value by the processing means of the control means 150. It has changed the supply situation. For this reason, by supplying electric power from the first resonance means 130 and the second resonance means 140 and 240 in a state where different frequencies are superimposed, the magnetic permeability of the article to be heated 101 fluctuates, and the AC power having a particularly high frequency is obtained. The amount of fluctuation in power due to fluctuations in the impedance of the first resonance means 130 for supplying the power can be corrected, high-frequency AC power can be stably supplied, good induction heating efficiency can be obtained, and good contour quenching can be performed. can get.

  And the control means 150 is based on the ratio of the change of the impedance of the 1st resonance means 130 which fluctuates by superimposing the frequency in the 2nd resonance means 140,240 and supplying alternating current power. Recognizing the rate at which the permeability changes, the magnitude of the AC power supplied by the first resonance means 130 is controlled. For this reason, the magnitude of the power supplied by the first resonance means 130 corresponding to the rate of change in the magnetic permeability of the article to be heated 101 can be easily recognized by the impedance, and control for stable power supply can be easily performed. .

  Furthermore, the control means 150 controls the magnitude of the electric power supplied by the first resonance means 130 based on the formula 1 specifically. For this reason, it is possible to control the fluctuation amount of the power supplied by the first resonance means 130 to an appropriate power level only by calculation, and the impedance changes corresponding to the fluctuation of the magnetic permeability in the first resonance means 130. It is possible to easily control the magnitude of power supplied according to the situation. In particular, based on the rate of change of the impedance based on the experimental value, Formula 1 for correcting the changing ratio, that is, Formula 1 corresponding to the rate of change of the impedance that varies exponentially is obtained. The correction value is calculated. Therefore, it is possible to obtain a control that appropriately compensates for the decrease in power. Furthermore, even when the shape of the article to be heated 101, the induction heating conditions, and the like are different, the control can be performed by Expression 1, and versatility can be improved. Further, the conversion value acquisition unit of the control unit 150 acquires a correction value for correcting the amount of power that fluctuates by calculation based on Equation 1. For this reason, what is necessary is just to calculate a correction value suitably according to induction heating conditions, such as the shape and material of the to-be-heated material 101, and a hardening state, and can improve versatility.

  Further, the control means 150 converts the supplied DC power into AC power of a predetermined frequency and supplies it to the induction heating coil 110 to the first inverter 131B of the first oscillation means 131 in the first resonance means 130. The first oscillation means 131 detects the fluctuation of the supplied DC power, and the first oscillation means 131 converts the DC power supplied by the second inverters 141B and 241B of the second oscillation means 141 and 241 in the second resonance means 140 and 240. It is maintained in the state of the DC power supplied to the first inverter 131B in the first oscillating means 131 just before being converted to AC power having a frequency lower than the frequency to be converted and superimposed on the frequency and supplied to the induction heating coil 110. To control. For this reason, the control maintained in the power state supplied by the first resonance means 130 before the power is supplied in the state where the frequency is superimposed can be easily obtained by the simple control of the DC power.

  In the configuration of the induction heating apparatus 100 shown in FIG. 1, the second resonance means 140 has the voltage form of the second oscillation means 141, the output side of the second oscillation means 141 and the first transformer. The reactor L1 is connected in series to the secondary side of 120 and attenuates the feedback of the frequency of the first resonance means 130. For this reason, with a simple configuration in which a relatively small reactor L1 that attenuates frequency feedback is provided, the second oscillating means 141 is converted, for example, from an AC power source to a DC power source and then to an AC power source of a predetermined frequency. A voltage type that can be easily configured can be used.

  In the configuration of the induction heating apparatus 200 shown in FIG. 2, the first resonance unit 130 is connected in series to the primary side of the first transformer 120 on the output side of the first oscillation unit 131. The first capacitor C1 that compensates the reactive power of the transformer 120 and the induction heating coil 110 and attenuates the frequency component fed back from the second resonance means 240 by the first transformer 120 is provided. The second resonance means 240 is connected in series to the secondary side of the first transformer 120 on the output side of the second oscillation means 241, and suppresses frequency feedback from the first resonance means 130. In addition, a third capacitor C3 that compensates the reactive power of the first transformer 120 and the induction heating coil 110 is provided. For this reason, by setting the secondary side of the first transformer 120 to a low inductance, it becomes a low impedance for the current of the lower frequency supplied by the second resonance means 240. The current is bypassed, and the object to be heated 101 is efficiently heated by the induction heating coil 110 by the lower frequency of the second resonance means 240. Also, the third capacitor C3 of the second resonance means 240 compensates for the reactive power of the first transformer 120 having a low inductance, so that the impedance of the first resonance means 130 is low for the higher frequency current. The third capacitor C3 of the second resonance means 240 bypasses the current of the higher frequency, and is heated by the induction heating coil 110 by the higher frequency of the first resonance means 130. The object 101 is efficiently induction heated. And since the secondary side of the 1st transformer 120 functions as a reactor for preventing the high frequency feedback of the 1st resonance means 130, the 2nd resonance means 240 is made to have a high frequency of the 1st resonance means 130. Therefore, it is not necessary to provide a reactor or the like for preventing the feedback, and the configuration is simplified.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and various modifications such as modifications and improvements within the scope that can achieve the object of the present invention without departing from the gist of the present invention are included in the present invention. It is.

  For example, the induction heating apparatus 100 shown in FIG. 1, that is, the voltage type series resonance type as the first resonance unit 130 and the voltage type series resonance type as the second resonance unit 140, for example, the configuration shown in FIG. 5. It is good. FIG. 5 is a circuit diagram showing a schematic configuration of an induction heating apparatus according to still another embodiment of the present invention. The same configuration as that of induction heating apparatus 100 shown in FIG. 1 and induction heating apparatus 200 shown in FIG. The same reference numerals are given and description thereof is omitted. Specifically, an induction heating apparatus 300 shown in FIG. 5 includes an induction heating coil 110, a first transformer 120, a voltage-type series resonance type first resonance unit 330 on the high frequency side, and a medium frequency side. Voltage type series resonance type second resonance means 340.

  The 1st resonance means 330 is provided with the 1st oscillation means 131 similar to the induction heating apparatus 100 shown in FIG. 1, and the 1st capacitor | condenser C1. Similar to the induction heating device 100, the first resonance unit 330 is connected between the output terminals of the first inverter 131 </ b> B in the first oscillation unit 131 and the primary capacitors C <b> 1 and the primary transformer 120. A series circuit of the winding 121 is connected.

  The second resonance means 340 includes a second oscillation means 141 similar to the induction heating apparatus 100 shown in FIG. 1, a reactor L1, and a third capacitor C3. The reactor L1 is connected in series to the series circuit of the secondary winding 122 of the first transformer 120 and the induction heating coil 110 at the output terminal of the second inverter 141B and in parallel to the third capacitor C3. A high frequency feedback component in the resonance means 330 is attenuated to form a series resonance circuit.

  When the high frequency AC power converted by the first oscillating means 131 of the first resonance means 330 is output to the induction heating device 300, the first capacitor C1 enters the series resonance state, and the first transformer The voltage is converted into a predetermined voltage at 120 and supplied from the secondary winding 122 to the induction heating coil 110. When the high frequency is supplied to the induction heating coil 110, since the impedance of the third capacitor C3 of the second resonance means 340 is set to be sufficiently small, the high frequency current is bypassed and the high frequency is induced by the induction heating coil 110. 110 is efficiently supplied. By this high frequency supply, the induction heating coil 110 induction-heats the article 101 to be heated. Note that the reactor L1 of the second resonance means 340 attenuates the high-frequency feedback from the first resonance means 330, and the damage of the second resonance means 340 due to the high-frequency feedback is prevented.

  When the medium frequency AC power converted by the second oscillating means 141 of the second resonance means 340 is output, the third capacitor C3 and the reactor L1 enter a series-parallel resonance state, and the induction heating coil 110 receives Medium-frequency AC power is supplied and the object to be heated 101 is induction-heated. When supplying the intermediate frequency, like the induction heating apparatus 100 shown in FIG. 1, the first capacitor C1 attenuates the feedback of the intermediate frequency, and the secondary winding 122 of the first transformer 120 is bypassed. Medium frequency is supplied efficiently.

  In the induction heating apparatus 300 shown in FIG. 5, similarly to the induction heating apparatus 100 shown in FIG. 1, a second inverter 141 </ b> B that is a voltage source inverter is used as a medium frequency supply, and the output terminal of the second inverter 141 </ b> B is used. Further, the reactor L1 is connected in series to attenuate the high-frequency feedback in the first resonance means 330, 130 to form a series-parallel resonance circuit. For this reason, a voltage form that can be easily converted into AC power having a predetermined frequency can be obtained with a simple configuration in which the reactor L1 is provided. Since the reactor L1 only needs to attenuate high-frequency feedback, the reactor L1 is cheaper than the reactor Lf required when the current source inverter is used, and the cost can be easily reduced.

  Further, as the induction heating device of the present invention, current source inverters may be used on the high frequency side and the medium frequency side, respectively. That is, instead of the voltage source inverter in the first resonance means 130 of the induction heating apparatus 200 shown in FIG. 2, a current source inverter may be used as shown in FIG. FIG. 6 is a circuit diagram showing a schematic configuration of an induction heating apparatus according to still another embodiment of the present invention. The same configuration as that of induction heating apparatus 100 shown in FIG. 1 and induction heating apparatus 200 shown in FIG. The same reference numerals are given and description thereof is omitted. Specifically, the induction heating apparatus 400 shown in FIG. 6 includes an induction heating coil 110, a first transformer 120, first resonance means 430 on the high frequency side, and second resonance on the medium frequency side. Means 240.

  The first resonance unit 430 includes a first oscillation unit 431, a parallel capacitor C5, and a series capacitor C6. Similar to the second oscillating means 241, the first oscillating means 431 includes a first converter 131A, a first reactor Lf1, and a first inverter 431B. The first inverter 431B converts the DC power input from the first converter 131A into high-frequency AC power having a predetermined frequency so that the current is an inverter and the DC current does not change suddenly through the first reactor Lf1. To do. The parallel capacitor C5 is connected in parallel to the primary winding 121 of the first transformer 120 and enters a parallel resonance state with a predetermined high-frequency AC power with a predetermined voltage output from the first inverter 431B. This parallel capacitor C5 compensates for the reactive power of the first transformer 120 and the induction heating coil 110. The series capacitor C6 is connected in series to the primary winding 121 of the first transformer 120, and forms a parallel series resonance circuit with the parallel capacitor C5. The series capacitor C6 compensates for the reactive power of the first transformer 120 and the induction heating coil 110, and attenuates the intermediate frequency component of the AC power fed back from the second resonance means 240 by the first transformer 120. To do.

  In the induction heating apparatus 400 shown in FIG. 6, when the high-frequency AC power converted by the first oscillation means 431 of the first resonance means 430 is output, the parallel capacitor C5 and the series capacitor C6 are in the parallel series resonance state. Thus, the first transformer 120 converts the voltage into a predetermined voltage and supplies the voltage from the secondary winding 122 to the induction heating coil 110 to inductively heat the article to be heated 101. When the high frequency is supplied to the induction heating coil 110, the high frequency feedback is suppressed by the third capacitor C3 of the second resonance means 240 in the same manner as the induction heating device 200 shown in FIG. C3 becomes a bypass, and high frequency is efficiently supplied to the induction heating coil 110.

  Further, when the medium frequency AC power converted by the second oscillation means 241 of the second resonance means 240 is output, the third capacitor C3 is connected in parallel resonance as in the induction heating device 200 shown in FIG. In this state, medium frequency AC power is supplied to the induction heating coil 110 to inductively heat the article to be heated 101. When supplying the intermediate frequency, similarly to the induction heating device 200 shown in FIG. 2, the secondary winding 122 of the first transformer 120 is bypassed, and the intermediate frequency is efficiently supplied to the induction heating coil 110. The series capacitor C6 attenuates the medium frequency component of the AC power fed back from the second resonance means 240 by the first transformer 120.

  In the induction heating apparatus 400 shown in FIG. 6, the first inverter 431 </ b> B that is a current source inverter is used as a high-frequency supply, and a parallel capacitor C <b> 5 is connected in parallel to the primary winding 121 of the first transformer 120. A series capacitor C6 that compensates the reactive power of the first transformer 120 and the induction heating coil 110 and attenuates the medium frequency component of the AC power fed back from the second resonance means 240 by the first transformer 120. A parallel series resonance circuit is configured. For this reason, even if damage such as short-circuiting of the induction heating coil 110 occurs, since the high-frequency current value is standardly small, it is possible to suppress damage of the first oscillation means 431 and the like.

  Further, as the induction heating device of the present invention, the configuration of the voltage source inverter of the induction heating device 200 shown in FIG. 2 and the configuration of the current source inverter are reversed, that is, the first resonance means of the induction heating device 300 shown in FIG. Instead of the voltage source inverter 130, a current source inverter may be used as shown in FIG. FIG. 7 is a circuit diagram showing a schematic configuration of an induction heating device according to still another embodiment of the present invention. The same components as those of the induction heating devices 100 to 400 described above are denoted by the same reference numerals and described. Is omitted. Specifically, the induction heating device 500 shown in FIG. 7 includes an induction heating coil 110, a first transformer 120, a first resonance means 430 similar to the induction heating device 400 shown in FIG. The second resonance means 340 similar to the induction heating apparatus 300 shown in FIG.

  In the induction heating apparatus 500, when the high-frequency AC power converted by the first oscillation unit 431 of the first resonance unit 430 is output, the parallel capacitor C5 and the series capacitor C6 are in a parallel series resonance state. The first transformer 120 converts the voltage into a predetermined voltage, which is supplied from the secondary winding 122 to the induction heating coil 110 to inductively heat the article to be heated 101. When the high frequency is supplied to the induction heating coil 110, the high frequency feedback from the first resonance means 430 is attenuated by the reactor L1 of the second resonance means 340, similarly to the induction heating apparatus 300 shown in FIG. The third capacitor C3 is bypassed, and the high frequency is efficiently supplied to the induction heating coil 110. When the medium frequency AC power converted by the second oscillating means 141 of the second resonance means 340 is output, the third capacitor C3 and the reactor L1 enter a series-parallel resonance state, and the induction heating coil 110 receives Medium-frequency AC power is supplied and the object to be heated 101 is induction-heated. At the time of supply of the intermediate frequency, like the induction heating device 400 shown in FIG. 6, the series capacitor C6 attenuates the intermediate frequency component of the AC power fed back from the second resonance means 340 by the first transformer 120. The secondary winding 122 of the first transformer 120 is bypassed, and the medium frequency is efficiently supplied to the induction heating coil 110.

  Further, as the induction heating device of the present invention, the converter and the smoothing capacitor in the induction heating device 300 shown in FIG. 5 are shared as shown in FIG. That is, when each inverter is a voltage type like the induction heating apparatus 100 shown in FIG. 1 or the induction heating apparatus 300 shown in FIG. 5, it is possible to share the power supply side that supplies DC power. FIG. 8 is a circuit diagram showing a schematic configuration of an induction heating device according to still another embodiment of the present invention. The same components as those of the induction heating devices 100 to 500 described above are denoted by the same reference numerals and described. Is omitted. An induction heating apparatus 600 shown in FIG. 8 includes an induction heating coil 110, a first transformer 120, a converter 650 that is a DC conversion means for converting AC power into DC power, a smoothing capacitor Cf, a first capacitor A resonance unit 630 and a second resonance unit 640 are provided.

  The converter 650 is a forward conversion circuit using various bridge rectifier circuits, for example, and is connected to the commercial AC power source e and converts AC power into DC power. The first resonance unit 630 includes a first inverter 131B that functions as a first oscillation unit, and a first capacitor C1. The first inverter 131B converts the DC power converted by the converter 650 and smoothed and input via the smoothing capacitor Cf into high-frequency AC power having a predetermined frequency. The second resonance unit 640 includes a second inverter 141B that functions as a second oscillation unit, a third capacitor C3, and a reactor L1. Then, the second inverter 141B converts the DC power converted by the converter 650 and smoothed via the smoothing capacitor Cf into medium frequency AC power having a predetermined frequency.

  The induction heating apparatus 600 shown in FIG. 8 converts the DC power converted by the converter 650 and smoothed by the smoothing capacitor Cf into a predetermined high-frequency AC power by the first inverter 131B, and the second inverter It is converted into predetermined medium frequency AC power at 141B. When high frequency AC power is output from the first inverter 131B of the first resonance means 630, the first capacitor C1 enters a series resonance state and is converted into a predetermined voltage by the first transformer 120. It is supplied from the secondary winding 122 to the induction heating coil 110 to heat the object 101 to be heated. When supplying the high frequency, as described above, the high frequency feedback from the first resonance means 630 is attenuated by the reactor L1 of the second resonance means 640, the third capacitor C3 is bypassed, and the high frequency is induced. It is efficiently supplied to the heating coil 110. When medium frequency AC power is output from the second inverter 141B of the second resonance means 640, the third capacitor C3 and the reactor L1 enter a series-parallel resonance state, and the induction heating coil 110 has a medium frequency AC power. Electric power is supplied to inductively heat the article to be heated 101. When supplying the medium frequency, as described above, the first capacitor C1 attenuates the feedback of the medium frequency, and the secondary winding 122 of the first transformer 120 is bypassed, so that the medium frequency is efficiently supplied. .

  In the induction heating device 600 shown in FIG. 8, the converter 650 and the smoothing capacitor Cf are shared, the number of parts is reduced, and the productivity is improved, the device cost is reduced, and the size and weight are reduced. Furthermore, it is possible to easily obtain a facility in which only one power source is connected and equipment is reduced.

  Further, as the induction heating device of the present invention, in the configuration in which the converter 650 in the induction heating device 600 shown in FIG. 8 is shared, for example, as shown in FIG. 9, the first inverter 131B of the induction heating device 600 has a current type. This is a configuration using an inverter. That is, the converter is shared in the induction heating apparatus 500 shown in FIG. FIG. 9 is a circuit diagram showing a schematic configuration of an induction heating device according to still another embodiment of the present invention. The same components as those of each of the induction heating devices 100 to 600 described above are denoted by the same reference numerals and described. Is omitted. Specifically, the induction heating device 700 shown in FIG. 9 includes an induction heating coil 110, a first transformer 120, a converter 650, a smoothing capacitor Cf, a first resonance means 730, and a second resonance. Means 640.

  The first resonance unit 730 includes a first oscillation unit 731, a parallel capacitor C 5, and a series capacitor C 6. The first oscillating means 731 includes a chopper circuit 760 connected to the converter 650 via a smoothing capacitor Cf, a reactor L3, and a first inverter 431B. Then, the first oscillating means 731 first interrupts the DC power converted by the converter 650 and smoothed by the smoothing capacitor Cf by the chopper circuit 760, so that the DC current does not change suddenly through the reactor L3. The signal is input to 431B and converted into high-frequency AC power having a predetermined frequency.

  In addition, the induction heating apparatus 700 shown in FIG. 9 is configured so that the DC power converted by the converter 650 and smoothed by the smoothing capacitor Cf is appropriately cut off by the chopper circuit 760 so that the DC current does not change suddenly through the reactor L3. The first inverter 131B is input to convert it into high-frequency AC power having a predetermined frequency, and the second inverter 141B converts it into predetermined medium-frequency AC power. When the high-frequency AC power converted by the first oscillation means 731 of the first resonance means 730 is output, as described above, the parallel capacitor C5 and the series capacitor C6 enter the parallel series resonance state, and the first The voltage is converted to a predetermined voltage by the transformer 120 and supplied to the induction heating coil 110 from the secondary winding 122 to inductively heat the object to be heated 101. At the time of supplying the high frequency, as described above, the high frequency feedback from the first resonance means 730 is attenuated by the reactor L1 of the second resonance means 640, the third capacitor C3 is bypassed, and the high frequency is induced. It is efficiently supplied to the heating coil 110. Further, when the medium frequency AC power converted by the second inverter 141B of the second resonance means 640 is output, the third capacitor C3 and the reactor L1 enter a series-parallel resonance state, and the induction heating coil 110 has a medium The alternating current power of a frequency is supplied and the to-be-heated material 101 is induction-heated. When supplying the medium frequency, as described above, the first capacitor C1 attenuates the feedback of the medium frequency, and the secondary winding 122 of the first transformer 120 is bypassed, so that the medium frequency is efficiently supplied. .

  Furthermore, as an induction heating apparatus of the present invention, the induction heating apparatus 700 shown in FIG. 9 has been illustrated with respect to a configuration in which an inverter uses an inverter on the high frequency side, but conversely, a current source inverter may be used on the intermediate frequency side. Furthermore, it is good also as a structure which aimed at sharing of a converter also about the structure which uses a current source inverter for both.

  In addition, as described above, the object to be heated 101 is any one that is induction-heated, such as a steel pipe, a complex-shaped gear having a plurality of irregularities on the surface, or a composite material in which a plurality of members are laminated. Can be targeted. Moreover, although the structure which supplies a high frequency and a medium frequency was demonstrated, it is good also as a structure which supplies another frequency. Furthermore, not only the high frequency and the medium frequency but also a configuration in which at least two different frequencies can be superimposed and supplied can be provided.

  And although it demonstrated as a structure provided with the induction heating coil 110 in the structure of the induction heating apparatuses 100-700, the induction heating coil comprised corresponding to the to-be-heated object 101 which carries out induction heating by making the induction heating coil 110 into another body. 110 may be appropriately connected.

  Further, as the control means 150, both the first oscillating means 131, 431 and the second oscillating means 141, 241 are controlled, or the converter 650, the first inverter 131B and the second inverter 141B are controlled respectively. Further, the converter 650, the chopper circuit 760, the first inverter 131B, and the second inverter 141B are controlled, respectively. However, for example, the high-frequency side control for controlling the first oscillation means 131, 431 is described. The control unit may be divided into the control unit and the control unit on the medium frequency side that controls the second oscillation unit 141, 241 and may be controlled separately.

  Furthermore, the control is not limited to the correction value obtained by calculation based on Equation 1, but for example, as described above, the matrix is set in advance based on the shape and material of the object to be heated 101, induction heating conditions, and the like. For each of the shapes and materials of the object to be heated 101 and the calculation based on the formula set in more detail from Formula 1, specifically, the set value and the current value are not directly proportional to each other. In the case of a functional relationship such as quadratic or exponential, any correction that corrects a reduction in power on the high frequency side that is supplied corresponding to the magnetic permeability that the object to be heated 101 fluctuates, such as performing a correction based on the function, etc. The control method can be used.

  Further, the control means 150 is not limited to the control means 150 that constitutes the induction heating devices 100 to 700, and the control means 150 that can be appropriately connected to an induction heating device and controls the supply of AC power appropriately may be configured independently. .

  In addition, the specific structure and procedure for carrying out the present invention may be changed to other configurations as long as the object of the present invention can be achieved.

It is a circuit diagram which shows schematic structure of the induction heating apparatus which concerns on one embodiment of this invention. It is a circuit diagram which shows the experimental apparatus which is other embodiment of this invention for setting the control method which controls the magnitude | size of the electric power supplied by the 1st resonance means in the said one Embodiment. 2 is a timing chart for explaining the timing for measuring the voltage value and the current value in the first resonance means according to the supply status of AC power of different frequencies in the experiment by the experimental apparatus shown in FIG. 2 in the embodiment. ) Is a waveform diagram showing the supply status of AC power in the first resonance means, and (B) is a waveform diagram showing the AC power supply status in the second resonance means. According to the experiment by the experimental apparatus shown in FIG. 2 in the above embodiment, the impedance of the first resonance means with respect to the magnitude of the medium frequency bias current when the AC power is supplied with the frequency superimposed by the second resonance means. It is a graph which shows a change rate. It is a circuit diagram which shows schematic structure of the induction heating apparatus which concerns on other embodiment of this invention. It is a circuit diagram which shows schematic structure of the induction heating apparatus which concerns on other embodiment of this invention. It is a circuit diagram which shows schematic structure of the induction heating apparatus which concerns on other embodiment of this invention. It is a circuit diagram which shows schematic structure of the induction heating apparatus which concerns on other embodiment of this invention. It is a circuit diagram which shows schematic structure of the induction heating apparatus which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,200,300,400,500,600,700 ... Induction heating apparatus 101 ... To-be-heated object 110 ... Induction heating apparatus 120 ... First transformer 130, 330, 430, 630, 730 ... Resonance means First resonance means 131, 431, 731... First oscillation means 131B... First inverter 140, 240, 340, 640 which can also function as first oscillation means. Second resonance which is resonance means. Means 141, 241 ... second oscillating means 141B ... second inverter that can also function as second oscillating means

Claims (19)

An induction heating control device for controlling a heating device for induction heating the object to be heated by supplying electric power of different frequencies from a plurality of resonance means to an induction heating coil for induction heating the object to be heated,
Resonance means for supplying high frequency power corresponding to a change in magnetic permeability of the object to be heated by superimposing at least two frequencies with different power supplied by the resonance means and supplying power to the induction heating coil Conversion value acquisition means for acquiring a conversion value for maintaining the power that changes in magnitude in the power state that was supplied immediately before supplying at least two different frequencies superimposed on each other;
Based on the conversion value acquired by the conversion value acquisition means, processing means for changing the supply status of the power supplied from the resonance means for supplying the high frequency power, and
An induction heating control device comprising: An induction heating control device for controlling a heating device for induction heating the object to be heated by supplying electric power of different frequencies from a plurality of resonance means to an induction heating coil for induction heating the object to be heated,
In response to a change in the impedance of the resonance means that supplies high frequency power by superimposing at least two different frequencies of power supplied by the resonance means to supply power to the induction heating coil, this high frequency A conversion value acquisition means for acquiring a conversion value for maintaining the power state that was supplied immediately before the power having a magnitude changed by the resonance means for supplying the power is supplied in a state where the at least two different frequencies are superimposed and supplied; ,
Based on the conversion value acquired by the conversion value acquisition means, processing means for changing the supply status of the power supplied from the resonance means for supplying the high frequency power, and
An induction heating control device comprising: The induction heating control device according to claim 1 or 2,
The said conversion value acquisition means acquires the said conversion value by a calculation. The induction heating control apparatus characterized by the above-mentioned. The induction heating control device according to claim 1 or 2,
The said conversion value acquisition means reads and acquires the said conversion value calculated beforehand and memorize | stored in the memory | storage means. The induction heating control apparatus characterized by the above-mentioned. An induction heating coil that induction-heats an object to be heated, and a heating device that includes a plurality of resonance means capable of supplying electric power of different frequencies to the induction heating coil by superimposing at least two different frequencies;
The induction heating control device according to any one of claims 1 to 4, which controls the resonance means of the heating device;
An induction heating apparatus comprising: An induction heating coil for induction heating the object to be heated;
First resonance means for inductively heating the object to be heated by supplying electric power of a predetermined frequency to the induction heating coil;
Second resonance means for inductively heating the object to be heated by supplying electric power having a frequency lower than that of the first resonance means to the induction heating coil;
A transformer having a primary side connected to the first resonance means and a secondary side connected to the second resonance means;
Control means for controlling the first resonance means and the second resonance means to supply electric power of a predetermined frequency,
The control means supplies the electric power to the induction heating coil by superimposing the frequency of the electric power supplied by the first resonance means and the frequency of the electric power supplied by the second resonance means, thereby the object to be heated. An induction heating apparatus characterized by controlling the magnitude of the electric power supplied by the first resonance means in accordance with the rate at which the magnetic permeability of the liquid crystal changes. The induction heating device according to claim 6,
The control means sets a rate at which the permeability of the object to be heated changes based on the ratio of the impedance of the first resonance means that fluctuates by supplying power with the frequency superimposed by the second resonance means. Recognizing and controlling the magnitude of electric power supplied by the first resonance means. An induction heating coil for induction heating the object to be heated;
First resonance means for inductively heating the object to be heated by supplying electric power of a predetermined frequency to the induction heating coil;
Second resonance means for inductively heating the object to be heated by supplying electric power having a frequency lower than that of the first resonance means to the induction heating coil;
A transformer having a primary side connected to the first resonance means and a secondary side connected to the second resonance means;
Control means for controlling the first resonance means and the second resonance means to supply electric power of a predetermined frequency,
The control means supplies the first resonance means in response to the impedance fluctuation state of the first resonance means that fluctuates by supplying power with the frequency superimposed by the second resonance means. An induction heating device characterized by controlling the magnitude of electric power. The induction heating device according to claim 7 or 8,
The control means controls the magnitude of power supplied by the first resonance means so that the impedance of the first resonance means is maintained at an impedance immediately before the power is supplied from the second resonance means. An induction heating device characterized by that. An induction heating apparatus according to any one of claims 6 to 9,
The control means controls the magnitude of electric power supplied by the first resonance means based on the following expression 1. Expression 1: VRn = (1 / ((1-Y) e ^{−x / p} + Y) ^1/2 ) × VR1
VRn: power ratio supplied from the first resonance means after correction
VR1: Power ratio supplied from the first resonance means before correction
x: Power ratio supplied from the second resonance means
Y: Load resistance of the first resonance means when supplying from the second resonance means at the standard maximum power value (VR2max)
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)
An induction heating device characterized by that. An induction heating apparatus according to any one of claims 6 to 9,
The first resonance means includes first oscillating means for converting supplied DC power into AC power having a predetermined frequency and supplying the AC power to the induction heating coil.
The second resonance means includes second oscillating means for converting the supplied DC power to AC power having a frequency lower than the frequency converted by the first oscillating means and supplying the AC power to the induction heating coil.
The control means supplies the power by superimposing the frequency by the second resonance means on the frequency of the power supplied from the first resonance means, thereby changing the DC power supplied to the first oscillation means. And the magnitude of the power supplied by the first resonance means is controlled so that the frequency is superimposed by the second resonance means and maintained at the DC power immediately before the power is supplied. Induction heating device. An induction heating coil for induction heating the object to be heated;
First resonance means for inductively heating the object to be heated by supplying electric power of a predetermined frequency to the induction heating coil;
Second resonance means for inductively heating the object to be heated by supplying electric power having a frequency lower than that of the first resonance means to the induction heating coil;
A transformer having a primary side connected to the first resonance means and a secondary side connected to the second resonance means;
The first resonance unit and the second resonance unit can supply power to the induction heating coil by superimposing the frequency of the power supplied by the first resonance unit and the frequency of the power supplied by the second resonance unit. Control means for controlling the magnitude of the electric power supplied by the first resonance means based on the following formula 1;
Formula 1: VRn = (1 / ((1-Y) e- ^{x / p} + Y) ^1/2 ) * VR1
VRn: power ratio supplied from the first resonance means after correction
VR1: Power ratio supplied from the first resonance means before correction
x: Power ratio supplied from the second resonance means
Y: Load resistance of the first resonance means when supplying from the second resonance means at the standard maximum power value (VR2max)
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)
An induction heating apparatus comprising: An induction heating coil for induction heating the object to be heated;
First oscillating means for converting supplied DC power into AC power of a predetermined frequency, and supplying the converted AC power to the induction heating coil to inductively heat the object to be heated. When,
Second oscillating means for converting supplied DC power into AC power having a frequency lower than the frequency converted by the first oscillating means is provided, and the converted AC power is supplied to the induction heating coil to be heated. A second resonance means for inductively heating the object;
A transformer having a primary side connected to the first resonance means and a secondary side connected to the second resonance means;
The frequency of the alternating current power supplied by the first resonance means and the frequency of the alternating current power supplied by the second resonance means for the direct current power supplied to the first oscillation means and the second oscillation means. Control is performed so that AC power can be supplied to the induction heating coil by superimposing, and the DC power supplied to the first oscillating means is superimposed on the frequency by the second resonance means and immediately before AC power is supplied. Control means for controlling the state to be maintained at DC power;
An induction heating apparatus comprising: The induction heating device according to claim 11 or 13,
The first resonance means is connected in series with the primary side of the transformer on the output side of the first oscillation means to compensate for the reactive power of the transformer and the induction heating coil, and the transformer A capacitor for attenuating the frequency component fed back from the second resonance means;
The second resonance means is connected in series to the secondary side of the transformer on the output side of the second oscillation means and suppresses frequency feedback from the first resonance means, and the transformer and the An induction heating apparatus comprising a capacitor for compensating reactive power of an induction heating coil. An induction heating apparatus according to any one of claims 11, 13, and 14,
The second resonance means includes
The second oscillating means is a voltage type;
An induction heating apparatus comprising a reactor connected in series to the output side of the second oscillation means and the secondary side of the transformer to attenuate the frequency feedback of the first resonance means. An induction heating method for inductively heating the object to be heated by causing an induction heating coil for induction heating the object to be heated to supply electric power of different frequencies from a plurality of resonance means,
The resonance that supplies high frequency power in accordance with the rate at which the magnetic permeability of the object to be heated changes by superimposing at least two frequencies of power supplied from the resonance means to the induction heating coil. An induction heating method characterized by controlling the magnitude of electric power supplied by the means. An induction heating method for inductively heating the object to be heated by causing an induction heating coil for induction heating the object to be heated to supply electric power of different frequencies from a plurality of resonance means,
The high frequency corresponding to the impedance fluctuation state of the resonance means for supplying high frequency power by superimposing at least two frequencies of power supplied from the resonance means to supply power to the induction heating coil. An induction heating method characterized by controlling the magnitude of electric power supplied by a resonance means for supplying electric power. An induction heating method for inductively heating the object to be heated by causing an induction heating coil for induction heating the object to be heated to supply electric power of different frequencies from a plurality of resonance means,
When supplying power to the induction heating coil by superimposing at least two frequencies of the power supplied from the resonance means, the power supplied by the resonance means that supplies high frequency power based on the following equation 1 Equation 1: VRn = (1 / ((1-Y) e- ^{x / p} + Y) ^1/2 ) * VR1
VRn: power ratio supplied from the high frequency side resonance means after correction
VR1: Ratio of power supplied from resonance means on the high frequency side before correction
x: Ratio of power supplied from resonance means on the lower frequency side
Y: Load resistance of the first resonance means when supplying the standard maximum power value (VR2max) from the resonance means on the low frequency side
p: damping constant (p = VR2max / ABS {ln (1%)}, ABS {m}: absolute value of m)
An induction heating method characterized by that. An induction heating method in which the object to be heated is induction-heated by being supplied to an induction heating coil that induction-heats the object to be heated from a plurality of resonance means that respectively convert direct-current power into alternating-current power of a predetermined different frequency,
When the AC power is supplied to the induction heating coil by superimposing at least two frequencies of the AC power supplied from the resonance means, the DC power supplied to the resonance means for supplying high frequency AC power is reduced. The induction heating method is characterized in that the resonance means for supplying alternating-current power with a frequency is controlled so as to maintain the direct-current power immediately before the alternating-current power is supplied.

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