JP2003347019A - Electromagnetic induction heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter type electromagnetic induction heating apparatus to carry out induction heating by efficiently supplying desired power to objects to be heated having different materials. <P>SOLUTION: This electromagnetic induction heating apparatus is provided with a resonant circuit including an object to be heated and an inverter to supply power to the resonant circuit by converting a DC voltage to an AC voltage, and the inverter is provided with a plurality of upper and lower arms, a heating coil, a drive circuit to drive switching elements provided in the upper and lower arms, and a control circuit to control the drive circuit. The control circuit controls the operation of this apparatus by selecting a drive circuit driven according to the material of the object to be heated and desired input power. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter-type electromagnetic induction heating apparatus for efficiently supplying desired power to an object to be heated of different materials and performing induction heating.

[0002]

2. Description of the Related Art In recent years, an inverter type electromagnetic induction heating apparatus for heating an object to be heated such as a pot without using a fire has been widely used. An electromagnetic induction heating device applies a high-frequency current to a heating coil to generate an eddy current in an object to be heated made of a material such as iron or stainless steel placed close to the coil, and the electric resistance of the object to be heated itself Generate heat.

[0003] This electromagnetic induction heating apparatus has been recognized as a new heat source because it can control the temperature of an object to be heated and has high safety. Conventionally, electric cookers incorporated in system kitchens and the like include sheathed heaters, plate heaters,
Although a heater using a resistor such as a halogen heater as a heat source has been used, in recent years, a heater in which a part is replaced with an induction heating cooker, or a heater in which two or more ports are replaced by an induction heating cooker is being replaced.

[0004] As a conventional example of such an electromagnetic induction heating device, there is an induction heating cooker as disclosed in Japanese Patent Application Laid-Open No. 2001-126833 (hereinafter referred to as known example 1).
In this publicly known example 1, a commercial AC power supply is rectified and smoothed and converted into a DC voltage, a high-frequency current is supplied to a heating coil by a half-bridge type inverter, and an object to be heated arranged close to the coil is induction-heated. .

Further, the electromagnetic cooker disclosed in Japanese Patent Application Laid-Open No. 2000-48945 (hereinafter referred to as "known example 2") is provided with constant changing means for changing the number of turns of the heating coil to change the circuit constant of the resonance circuit. Heat the object to be heated with the rated input.

[0006]

In the above-mentioned known example 1, it is necessary to supply a large current to the heating coil in order to supply sufficient electric power to the low-resistance object to be heated. This increases the heating efficiency and decreases.
FIG. 20 shows the equivalent impedance of the coil and the magnetically coupled object to be heated as viewed from the heating coil side, wherein the horizontal axis represents the equivalent inductance and the vertical axis represents the equivalent resistance. The equivalent impedance varies greatly depending on the material of the object to be heated. The object to be heated made of iron is (1) in the figure, the object to be heated is stainless steel (2), and the object to be heated is aluminum (3). Characteristics. Generally, an object to be heated having a high resistance as shown in (1) is suitable for induction heating. FIG. 21 shows FIG.
The relationship between the input power and the resonance current of the objects to be heated (1) and (2) having the equivalent impedance characteristics shown in FIG. As described above, in the known example 1, when the target input power is 2 kW, an output can be obtained by flowing a resonance current of about 40 A through the heating coil in the object to be heated (1). In the case of ()), a current of about 55 A needs to flow because the resistance is small.

Further, in the above-mentioned known example 2, since the circuit constant of the resonance circuit is switched using a relay, there are problems such as a problem of a contact life of the relay and a need for an expensive and large-sized relay having a large current capacity. .

SUMMARY OF THE INVENTION The present invention addresses the above-described problems and can efficiently supply desired electric power to objects to be heated of different materials without using an expensive and large-sized relay having a large current capacity. Problem of contact life and large current input. An object of the present invention is to provide an inverter-type electromagnetic induction heating device that does not have a bad influence of voltage fluctuation due to turning off.

[0009]

According to the present invention, there is provided a resonance circuit including an object to be heated, and an inverter for converting a DC voltage to an AC voltage and supplying power to the resonance circuit, wherein the inverters are connected in series. An electromagnetic induction heating device having an upper and lower arm composed of at least two switching elements, wherein the two switching elements are connected in series with each other to define an output terminal and the DC power supply. A heating coil constituting the resonance circuit and a resonance capacitor are connected to one of the extremes, and another heating coil constituting the resonance circuit is provided between the output terminal and the output terminals of the other upper and lower arms. A drive circuit for connecting and driving the switching elements of the upper and lower arms, and a control circuit for controlling these drive circuits are provided, and are driven according to the material of the object to be heated and the desired input power. It can be achieved by selecting a drive circuit for.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a circuit diagram of an electromagnetic induction heating apparatus according to a first embodiment of the present invention.

In FIG. 1, a commercial AC power supply 1 is applied to a rectifier circuit 2 and subjected to full-wave rectification, and then converted into a DC voltage by a smoothing circuit composed of an inductor 3 and a capacitor 4. In the DC power source of the converted DC voltage, the positive electrode side of the capacitor 4 is set to a point p, and the negative electrode side is set to an point o. Between the p point and the o point, two switching elements 10a, 1
0b and upper and lower arms 20 and 2 including two switching elements 20a and 20b.
An upper and lower arm 30 composed of two switching elements 30a and 30b is connected.

Switching element 10 of upper and lower arms 10
If the connection point between a and 10b, that is, the output terminal is point t, t
A resonance circuit 60 composed of the first heating coil 5 and the capacitor 6 is connected between the point and the point o.
Assuming that the connection point of the 0 switching elements 20a and 20b is point s, the second heating coil 7 is connected between the point s and the point t.

When the connection point of the switching elements 30a and 30b of the upper and lower arms 30 is point a, a third heating coil 9 is connected between the points a and s. The switching elements of the upper and lower arms 10, 20, and 30 are driven by drive circuits 61, 62, and 63, respectively, and convert a DC voltage into a high-frequency AC voltage.

The current detection element 71 detects a current flowing through the resonance circuit, and the resonance current detection circuit 72
1 is converted into a signal suitable for the input level of the control circuit 70. The current detection element 73 detects a current input from the commercial AC power supply 1, and the input current detection circuit 74 controls the output signal level of the current detection element 73 by the control circuit 7.
The signal is converted to a signal suitable for an input level of 0. The input power setting unit 75 is an interface for the user to set the input power, and controls the control circuit 70 according to the set output.
Send a signal to

The control circuit 70 determines the material and state of the object to be heated from the relationship between the input current and the resonance current, and starts or stops the heating operation. Further, power control is performed while selecting a drive circuit according to an output signal from the input power setting unit 75.

FIG. 2 shows the relationship between the number of turns of the heating coil and the equivalent resistance. As the number of turns increases, the magnetic flux increases, and the equivalent resistance of the object to be heated as viewed from the coil side increases. In FIG. 2, as described above, the equivalent resistance greatly differs depending on the material of the object to be heated. The object to be heated made of iron is (1) in the figure, the object to be heated made of stainless steel is (2), and the material to be heated is aluminum. The heated product has the properties as shown in (3). When the object to be heated has a high resistance as in (1), the number of turns of the heating coil may be small. However, when the object to be heated has a low resistance as in (3), in order to increase the heating efficiency, the number of turns of the coil is small. It is effective to increase the number of turns and increase the equivalent resistance.

In FIG. 1, when an object to be heated is placed near a heating coil and a user performs a heating operation, a control circuit 70 outputs signals from a resonance current detection circuit 72 and an input current detection circuit 74. The material of the object to be heated is detected by comparison, and a drive circuit to be driven is selected and controlled according to the material.

The detection of the material needs to be performed with low power and in a short time in order to prevent occurrence of overcurrent or overvoltage. In the initial stage of material detection in the present invention, the heating coil 5
This is performed under the condition that the number of turns is the largest using No. 7 and 9. This allows
The impedance of the resonance circuit increases, and the occurrence of overcurrent and overvoltage can be suppressed.

In FIG. 1, as a result of detecting the material,
A case where it is determined that the object to be heated is mainly made of an iron material will be described. When the user sets the high output heating, the control circuit 70 drives the drive circuit 61 to drive the upper and lower arms 1.
The switching elements 10a and 10b of 0 are alternately turned on and off, and a high-frequency current is supplied to the heating coil 5 and the capacitor 6.

At this time, the operation of the upper and lower arms 20 and 30 is stopped. In the case of low output heating, the control circuit 70 controls the drive circuit 62 or 63 according to the set output.
To control the upper and lower arms 20 or 30. When the upper and lower arms 20 are selected, the heating coils 5,
When the high-frequency current is supplied to 7 and the upper and lower arms 30 are selected, the high-frequency current is supplied to all of the heating coils 5, 7, and 9. As described above, by increasing the number of turns in accordance with the set output and reducing the current by using the increase in the equivalent resistance, it is possible to suppress the loss of the coil and the switching element.
Thereby, highly efficient induction heating can be realized.

Next, a case where it is determined that the object to be heated is made of stainless steel will be described. When the user performs a high-power heating operation, the control circuit 70 drives the drive circuit 62 to switch the switching elements 20a and 20a of the upper and lower arms 20.
0b are turned on and off alternately to supply a high-frequency current to the heating coils 5, 7 and the capacitor 6. At this time, the upper and lower arms 1
0 and the operation of the upper and lower arms 30 are stopped. In the case of low output heating, the control circuit 70 drives the drive circuit 63 to control the upper and lower arms 30. When the upper and lower arms 30 start operating, the high-frequency current is supplied to all of the heating coils 5, 7, and 9.

Next, a case where it is determined that the object to be heated is made of an aluminum material will be described. The control circuit 70 drives the drive circuit 63 to turn on and off the switching elements 30a and 30b of the upper and lower arms 30 alternately.
A high-frequency current is supplied to the capacitors 7 and 9 and the capacitor 6. At this time, the operation of the upper and lower arms 10 and 20 is stopped.

As described above, by selecting the arm to be driven according to the material of the object to be heated and the set output, it is possible to increase the heating efficiency by changing the number of turns of the heating coil and suppressing an increase in the resonance current. Further, since the resonance capacitor 6 can be shared regardless of the arm to be driven, an increase in the number of components can be suppressed. In addition, since it can be realized without using an expensive and large-sized relay having a large current capacity as in the past, there is a problem of contact life and a large current. It is possible to provide an electromagnetic induction heating device that does not have a bad influence of voltage fluctuation due to turning off.

In FIG. 1, the heating coil 9 is connected between the output terminals of the upper and lower arms 20 and 30. However, the heating coil 9 may be connected between the output terminals of the upper and lower arms 10 and 30. In this case, by setting the number of turns so that the equivalent impedance of the heating coil 9 is larger than that of the heating coil 7, the same effect as described above can be obtained. Further, the embodiment of FIG. 1 uses three heating coils 5, 7, and 9 to heat an iron, stainless steel, or aluminum object to be heated and an object to be heated made by combining these materials. However, a configuration in which the number of arms and the number of heating coils are further increased in order to heat the copper object to be heated which is most difficult to heat may be used.

A second embodiment will be described with reference to FIG.

FIG. 3 is a circuit configuration diagram of an electromagnetic induction heating device according to a second embodiment of the present invention, using two heating coils 5 and 7 (a first heating coil and a second heating coil). The circuit configuration is mainly for heating an object made of iron or stainless steel and an object made of a combination of these materials. The same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, the switching elements of the upper and lower arms 10 and 20 use IGBTs, which are power semiconductor switching elements. The upper and lower arms 10 are composed of an IGBT 11 and an IGBT 13 connected in series, and the upper and lower arms 20 are connected in series. IGBT21 and IGBT connected
23.

The diodes 12 and 14 are connected to the IGBTs 11 and 13 of the upper and lower arms 10 in anti-parallel, respectively. Similarly, diodes 22 and 24 are connected in antiparallel to the IGBTs 21 and 23 of the upper and lower arms 20, respectively.

In general, an IGBT has a low reverse breakdown voltage, and therefore a diode is provided in antiparallel. A capacitor 17 and an IGBT 18 are connected in series to the lower arm of the upper and lower arms 10, and a diode 19 is connected to the IGBT 18 in antiparallel.

Similarly, a capacitor 43 and an IGBT 44 are connected to the lower arm of the upper and lower arms 20 in series.
A diode 45 is connected in anti-parallel to T44.
The IGBTs 18 and 44 have drive circuits 64 and 65, respectively.
And controls the energization of the capacitors 17 and 43.

FIG. 4 is a plan view showing the configuration of the heating coils 5 and 7 of FIG.

The heating coil 5 has a structure in which a conductive wire is spirally wound, and a heating coil 7 is wound outside the heating coil 5.
The heating coil 5 and the heating coil 7 are connected at a point b.
Magnetic bodies 81 are radially provided on the lower surfaces of the heating coils 5 and 7 to prevent the magnetic flux generated from the coils from spreading below the coils.

FIG. 5 is a sectional view of the heating coil section taken along the line AA 'in the plan view shown in FIG.

The heating coils 5 and 7 have a coil support base 80.
And is disposed below the plate 82 on which the object to be heated 90 is placed. A high-frequency current is supplied to the heating coils 5 and 7 by the circuit shown in FIG. 3, and the magnetic flux generated from the coils interlinks with the object to be heated, causing an eddy current to flow, and generates heat by the electric resistance of the object itself. As described above, the magnetic material 81 adhered to the coil support base 80 is provided on the lower surfaces of the heating coils 5 and 7.

Next, the operation of FIG. 3 will be described with reference to the timing chart shown in FIG.

FIG. 6 shows waveforms when an object to be heated mainly made of iron is heated at a high output. In FIG. 3, when it is determined that the object to be heated is made of iron, the control circuit 70 drives the drive circuit 61 to control the upper and lower arms 10 to perform the heating operation mainly using the heating coil 5. Here, when driving the upper and lower arms 10, the IGBT 2 of the upper and lower arms 20 is used.
1, 23 and 44 are turned off. On the other hand, when the upper and lower arms 20 are driven, the IGBTs 11, 13, 1
Turn 8 off.

In FIGS. 3 and 6, the power supply voltage of the inverter, that is, the DC voltage is Vp, and the voltages between the collector and the emitter of the IGBTs 11 and 13 are Va1 and Vb1 respectively.
And The current flowing through the IGBT 11 and the diode 12 is Ia1, and the current flowing through the IGBT 13 and the diode 14 is Ib1. The current flowing through the heating coil 5 is IL5, and the direction of the heating coil 5 is defined as positive from the point t in FIG. The current flowing through the heating coil 7 is IL7, and the direction of the heating coil 7 is defined as positive from the point s in FIG.

In FIG. 3, when the drive signal of the IGBT 11 is turned on and the energy stored in the heating coil 5 becomes zero, the polarity of the resonance current IL5 changes from negative to positive and the IGBT 11
11, the resonance current I in the path of the heating coil 5 and the capacitor 6
L5 flows.

On the other hand, since the heating coil 7 is magnetically coupled to the heating coil 5 and the object to be heated, an induced voltage is generated in the heating coil 7. Therefore, a forward voltage is applied to the diode 22 of the upper and lower arms 20, and the heating coil 7,
Induction current IL7 in the path of diode 22 and IGBT11
Flows. The resonance current IL represented by a solid line as shown in FIG.
5, the induced current IL7 is a current in the opposite direction as shown by the broken line. Therefore, the IGBT 11 of the upper and lower arms 10 has the positive resonance current IL5 and the negative induction current IL7.
Flows.

Next, when the drive signal of the IGBT 11 is turned off, the resonance current IL5 has a positive polarity and the induced current IL7 has a negative polarity, and these currents are supplied to the capacitor 17 via the diode 19 of the upper and lower arms 10. And the capacitor 17 is discharged.

Therefore, the voltage Vb1 between the collector and the emitter of the IGBT 13, that is, the output voltage gradually decreases. Thereafter, when a forward voltage is applied to the diode 14, the resonance current IL5 continues to flow through the path of the heating coil 5, the capacitor 6, and the diode 14 as a circulating current. On the other hand, the induced current IL7 flows through the path of the diode 14, the heating coil 7, and the diode 22, and the energy stored in the heating coil 7 is discharged.

Next, when the drive signal of the IGBT 13 is turned on and the energy stored in the heating coil 5 becomes zero, the polarity of the resonance current IL5 changes from positive to negative, and the resonance current IL5 passes through the path of the capacitor 6, the heating coil 5 and the IGBT13. Flows. On the other hand, an induced voltage is generated in the heating coil 7, and a forward voltage is applied to the diode 24 of the upper and lower arms 20,
The induction current IL7 flows through the path of the heating coil 7, the IGBT 13, and the diode 24. Therefore, I
A negative-polarity resonance current IL5 and a positive-polarity induced current IL7 flow through the GBT 13.

Next, when the drive signal of the IGBT 13 is turned off, the resonance current IL5 has a negative polarity and the induced current IL7 has a positive polarity.
The capacitor 17 flows through the GBT 18 and the capacitor 17 is charged.

Therefore, the voltage Vb1 between the collector and the emitter of the IGBT 13, that is, the output voltage gradually increases. Thereafter, when a forward voltage is applied to the diode 12, the resonance current IL5 continues to flow through the path of the capacitor 6, the heating coil 5, and the diode 12 as a circulating current.

On the other hand, the induced current IL7 is
The energy flows through the path of the heating coil 7 and the diode 12, and the energy stored in the heating coil 7 is discharged. As described above, when heating a high resistance object to be heated with high output, a high-frequency current can be supplied to the heating coil by repeating the above operation. In FIG. 3, even if the capacitor 17, the IGBT 18, and the diode 19 of the upper and lower arms 10 and the capacitor 43, the IGBT 44, and the diode 45 of the upper and lower arms 20 are connected to the upper arm, the above-described effects can be obtained.

As described above, since the heating coil 5 and the heating coil 7 are magnetically coupled, when a current flows through the heating coil 5, an induced voltage is generated in the heating coil 7 and the upper and lower arms 2
0 of the upper and lower arms 10 via the diodes 22 and 24 of
The induced current is superimposed on the GBTs 11 and 13. To suppress the induced current, it is effective to weaken the magnetic coupling.

The third embodiment will be described with reference to FIG.

FIG. 7 is a sectional view of a heating coil portion of an electromagnetic induction heating device according to a third embodiment of the present invention.

In FIG. 7, magnetic members 83 and 84 are separately provided on the lower surfaces of the heating coils 5 and 7, respectively. Further, a magnetic body 85 is provided between the heating coil 5 and the heating coil 7 and is in contact with the magnetic body 83. Thereby, the magnetic flux generated from the heating coil 5 is guided toward the object to be heated 90, and thus the magnetic flux linked to the heating coil 7 is reduced. A magnetic body 86 is provided outside the heating coil 7 and is in contact with the magnetic body 84. This prevents the magnetic flux generated from the heating coil 7 from spreading outside the coil.

In FIG. 3, when heating an iron-made object with a low output, the control circuit 70 drives the drive circuit 62 to control the upper and lower arms 20. When the upper and lower arms 20 start operating, the high-frequency current is supplied to the heating coils 5 and 7. Also, when heating the stainless steel object to be heated, the control circuit 70 drives the drive circuit 62 to control the upper and lower arms 20 and performs the heating operation using the heating coil 5 and the heating coil 7.

The fourth embodiment will be described with reference to FIG.

FIG. 8 is a circuit diagram of an electromagnetic induction heating apparatus according to a fourth embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown. The same parts as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 8, the diodes 22 and 24 of the upper and lower arms 20 are connected in reverse series with the diodes 26 and 2 respectively.
8 are connected, and IGBTs 25 and 27 are connected to the diodes 26 and 28 in anti-parallel, respectively. Capacitors 29 and 31 are connected in parallel to the IGBTs 21 and 23 of the upper and lower arms 20, respectively.

As a result, when the IGBTs 21 and 23 are turned off, the change in the voltage applied between the collector and the emitter is reduced, and the turn-off loss can be reduced. Similarly, capacitors 15 and 16 are connected in parallel to the IGBTs 11 and 13 of the upper and lower arms 10, respectively, so that a change in voltage applied between the collector and the emitter is reduced.

As described above, since the heating coil 5 and the heating coil 7 are magnetically coupled, in FIG.
When the upper and lower arms 10 are driven to supply a current to the heating coil 5, an induced voltage is generated in the heating coil 7, and the induced current IL7
Are superimposed on the IGBTs 11 and 13 of the upper and lower arms 10 via the diodes 22 and 24 of the upper and lower arms 20. In FIG. 8, when the upper and lower arms 10 are driven,
When the 0 IGBTs 25 and 27 are turned off, the induced current is cut off by the diodes 26 and 28. On the other hand, the upper and lower arms 20
Are driven, the IGBTs 25 and 27 of the upper and lower arms 20 are moved.
Is turned on, the circulating current flows through the path of the capacitor 6, the heating coil 5, the heating coil 7, the diode 22, the IGBT 25, or the heating coil 7, the heating coil 5, the capacitor 6,
The current flows through the path of the diode 24 and the IGBT 27.

Here, the current of the heating coil 7 is diverted to the heating coil 5 and the capacitors 15 and 16 provided on the upper and lower arms 10. However, since the capacitance of the capacitors 15 and 16 is small and the reactance is large, the current flowing in the heating coil 5 is large. Is larger than the current flowing through both capacitors.

This fourth embodiment has two upper and lower arms 1
Although 0 and 20 and two heating coils 5 and 7 are shown, it is also possible to further add an upper and lower arm and a heating coil in order to diversify the material of the object to be heated.

The fifth embodiment will be described with reference to FIG.

FIG. 9 is a circuit diagram of an electromagnetic induction heating device according to a fifth embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown. Also, the same parts as those in FIG. 8 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 9, the point t and the point o
Between the points, a capacitor 17 and an IGBT 18 are connected in series, and a diode 19 is connected to the IGBT 18 in antiparallel. When the upper and lower arms 10 are driven to heat an iron object to be heated with a high output, the IGBT 18 is turned on, so that the capacitor 17 is connected to the lower arm.
The change in the voltage applied between the collector and the emitter of both IGBTs when 1, 13 is turned off is reduced. On the other hand, when the upper and lower arms 20 are driven, the capacitor 17 is cut off from the lower arm by turning off the IGBT 18, so that the current of the heating coil 7 is prevented from shunting and flowing to the capacitor 17. In FIG. 9, even if the capacitor 17, the IGBT 18, and the diode 19 are connected to the upper arm, the above-described effects can be obtained.

In the fifth embodiment, two upper and lower arms 1
Although 0 and 20 and two heating coils 5 and 7 are shown, it is also possible to further add an upper and lower arm and a heating coil in order to diversify the material of the object to be heated.

A sixth embodiment will be described with reference to FIG.

FIG. 10 is a circuit diagram of an electromagnetic induction heating device according to a sixth embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown. Also, the same parts as those in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 8 and 9 show that the upper and lower arms 20 have the diodes 26 and 28 in order to cut off the path of the induced current.
When the upper and lower arms 20 are driven, the loss of the diodes 26 and 28 occurs. In FIG. 10, a reverse current blocking IGBT 32 having a reverse breakdown voltage is connected to the upper arm of the upper and lower arms 20, and the diode 26 and the IGBT 21 in FIGS. 8 and 9 are replaced with one IGBT. .

As a result, since the loss of the diode 26 is reduced, the conversion efficiency is improved. Similarly, a reverse current blocking IGBT 33 is connected to the lower arm, and the diode 28 and the IGBT 23 shown in FIGS.
It has been replaced by GBT. In addition, IGB of upper arm
A reverse current blocking IGBT 34 is connected in anti-parallel to T32, and the diode 22 and the IGBT of FIGS.
25 has been replaced by one IGBT. Thereby, the loss of the diode 22 is reduced.

On the other hand, diodes 37 and 38 are provided in the lower arm.
Are connected in anti-series, and the IGBT 36 is connected to the diode 37 in anti-parallel. In addition, diode 3
8, a capacitor 39 is connected in parallel.

In FIG. 10, when the upper and lower arms 10 are driven and the IGBTs 34 and 36 of the upper and lower arms 20 are turned off, the induced current is cut off by the IGBTs 32 and 33. On the other hand, when the upper and lower arms 20 are driven, the IGBTs 34, 3
6, the circulating current flows through the path of the capacitor 6, the heating coil 5, the heating coil 7, the IGBT 34 or the heating coil 7, the heating coil 5, the capacitor 6, the diode 38,
It flows on the path of the IGBT 36.

The capacitor 39 is charged and discharged via the diode 37 or the IGBT 36 when the IGBT 32 or 33 is turned off. Thereby, s of the upper and lower arms 20
The change in the voltage at the point, ie, the output voltage, is reduced. In FIG. 10, the same operation as described above can be realized even if the configuration of the upper and lower arms of the upper and lower arms 20 is reversed.

In the sixth embodiment, two upper and lower arms 1
Although 0 and 20 and two heating coils 5 and 7 are shown, it is also possible to further add an upper and lower arm and a heating coil in order to diversify the material of the object to be heated.

The seventh embodiment will be described with reference to FIG.

FIG. 11 is a circuit diagram of an electromagnetic induction heating device according to a seventh embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown. Also, the same portions as those in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 11, the lower arm IGBT 33
A IGBT 35 of a reverse current blocking type is connected in anti-parallel, and the diode 24 and the IGBT 27 of FIGS. 8 and 9 or the diode 38 and the IGBT 36 of FIG.
The configuration has been replaced with BT. The lower arm of the upper and lower arms 20 includes a capacitor 43 and an IGBT 4
4 are connected in series, and a diode 45 is connected to the IGBT 44.
Are connected in anti-parallel.

In FIG. 11, when the upper and lower arms 10 are driven, if the IGBTs 34 and 35 of the upper and lower arms 20 are turned off, the induced current is cut off by the IGBTs 32 and 33. By turning off the IGBT 44, the capacitor 43 is turned off.
Is separated from the lower arm, so that the path through which the induced current flows is cut off. On the other hand, when the upper and lower arms 20 are driven and the IGBTs 34 and 35 are turned on, the circulating current flows through the capacitor 6, the heating coil 5, the heating coil 7, and the IGBT 34.
Or the path of the heating coil 7, the heating coil 5, the capacitor 6, and the IGBT 35.

By turning on the IGBT 44, the capacitor 43 is charged and discharged via the IGBT 44 or the diode 45 when the IGBT 32 or 33 is turned off. Thereby, the change of the voltage at the point s of the upper and lower arms 20, that is, the change of the output voltage is reduced. In FIG. 11, the capacitor 43, the IGBT 44 and the diode 45
Even if is connected to the upper arm of the upper and lower arms 20, the above-described effects can be obtained.

In the seventh embodiment, two upper and lower arms 1
Although 0 and 20 and two heating coils 5 and 7 are shown, it is also possible to further add an upper and lower arm and a heating coil in order to diversify the material of the object to be heated.

The eighth embodiment will be described with reference to FIG.

FIG. 12 is a circuit diagram of an electromagnetic induction heating device according to an eighth embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown.

In FIG. 12, a reverse current blocking IGBT 32 is connected to the upper arm of the upper and lower arms 20, and a reverse current blocking IGBT 33 is connected to the lower arm.
A capacitor 43 and an IGBT 44 are connected in series to the lower arm, and a diode 45 is connected to the IGBT 44 in antiparallel.

Next, the operation of FIG. 12 will be described with reference to FIG. FIG. 13 shows a waveform when the upper and lower arms 20 are driven. Here, when driving the upper and lower arms 20,
The IGBTs 11, 13, and 18 of the upper and lower arms 10 are off, and the heating operation using the heating coils 5 and 7 is performed.

On the other hand, when driving the upper and lower arms 10, the IGBTs 32, 33 and 44 of the upper and lower arms 20 are turned off.
12 and 13, currents flowing through the IGBTs 32 and 33 are Ia2 and Ib2, respectively.
The current flowing through is Isb2. The upper and lower arms 20
The output voltage at point s is Vs. The resonance currents flowing through the heating coils 5 and 7 are IL5 and IL7, respectively, and the direction of the arrow in FIG. 12 is defined as positive.

In FIG. 12, when the drive signal of the IGBT 32 is turned on and the energy stored in the heating coils 5 and 7 becomes zero, the polarity of the resonance currents IL5 and IL7 changes from negative to positive. At this time, if the value of the capacitor 43 is set so that the output voltage Vs of the upper and lower arms 20 becomes higher than the voltage Vp at the point p, that is, the power supply voltage of the inverter, the IGBT 3
No current flows because a reverse voltage is applied to 2.

Accordingly, the resonance currents IL5 and IL7 flow through the path of the capacitor 43, the heating coil 7, the heating coil 5, the capacitor 6, and the diode 45. When the output voltage Vs becomes equal to or lower than the power supply voltage Vp of the inverter, the IGBT 32 becomes conductive, and the resonance currents IL5 and IL7 become IGBT3.
2, flows through the path of the heating coil 7, the heating coil 5, and the capacitor 6.

Next, when the drive signal of the IGBT 32 is turned off, the resonance currents IL5 and IL7 have positive polarities,
The heating coil 7, the heating coil 5, the capacitor 6, the diode 45, and the capacitor 43 continue flowing through the path.

Next, when the drive signal of the IGBT 33 is turned on and the energy stored in the heating coils 5 and 7 becomes zero, the polarity of the resonance currents IL5 and IL7 changes from positive to negative. At this time, the output voltage Vs of the upper and lower arms 20 is lower than the voltage at the point o, and no current flows because a reverse voltage is applied to the IGBT 33. Therefore, the resonance currents IL5 and IL7
Flows through the path of the capacitor 6, the heating coil 5, the heating coil 7, the capacitor 43, and the IGBT 44. Output voltage Vs
Becomes higher than the voltage at the point o, the IGBT 33 becomes conductive, and the resonance currents IL5 and IL7 flow through the path of the capacitor 6, the heating coil 5, the heating coil 7, and the IGBT 33.

Next, when the drive signal of the IGBT 33 is turned off, the resonance currents IL5 and IL7 have negative polarities,
Heating coil 5, heating coil 7, capacitor 43, IGB
T44, the flow continues in the path of the capacitor 6. Thus, by repeating the above operation, a high-frequency current can be supplied to the heating coil. In FIG.
The capacitor 43, the IGBT 44, and the diode 45 may be connected to the upper arm of the upper and lower arms 20.

As described above, in this embodiment, the upper and lower arms 2
When each IGBT of 0 is turned off, the output voltage becomes equal to or higher than the power supply voltage of the inverter. Normally, the output voltage of the current resonance type inverter is limited to the power supply voltage of the inverter, and therefore the upper limit of the equivalent resistance is determined by the desired maximum power. In this embodiment, by increasing the output voltage, the upper limit of the equivalent resistance can be made higher than that of the current resonance type inverter of the above embodiment. Therefore, it is possible to obtain a desired input power by increasing the number of turns to increase the equivalent resistance and reduce the current. As a result, it is possible to reduce the loss of the used parts and to increase the heating efficiency.

In the eighth embodiment, two upper and lower arms 1
Although 0 and 20 and two heating coils 5 and 7 are shown, it is also possible to further add an upper and lower arm and a heating coil in order to diversify the material of the object to be heated.

The ninth embodiment will be described with reference to FIG.

FIG. 14 is a circuit diagram of an electromagnetic induction heating device according to a ninth embodiment of the present invention.

In FIG. 14, the upper arm of the upper and lower arms 20 has a diode 26 and an IGBT 21 connected in series. Similarly, the lower arm has a diode 28 and an IGBT 23
Are connected in series. Diodes 22 and 24 are connected in anti-parallel to the IGBTs 21 and 23, respectively.
No reverse voltage is applied to the IGBT. Although the embodiment of FIG. 12 uses an IGBT having a reverse withstand voltage characteristic, an IGBT having no reverse withstand voltage as in the present embodiment may be used.

In the ninth embodiment, two upper and lower arms 1
Although 0 and 20 and two heating coils 5 and 7 are shown, it is also possible to further add an upper and lower arm and a heating coil in order to diversify the material of the object to be heated.

A tenth embodiment will be described with reference to FIG.

FIG. 15 is a circuit diagram of an electromagnetic induction heating device according to a tenth embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown. In addition, the same parts as those in FIG. 14 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 14, the upper arm of the upper and lower arms 20 has a diode 26 and an IGBT 21 connected in series. Similarly, the lower arm has a diode 28 and an IGBT 23
Are connected in series. Diodes 22 and 24 are connected in anti-parallel to the IGBTs 21 and 23, respectively.
Diodes 26 and 28 have capacitors 48 and 4 respectively.
9 are connected in parallel. A capacitor 50 is connected to the lower arm.

In FIG. 15, when the material to be heated is mainly made of iron, the upper and lower arms 10 and 20 are driven simultaneously, and when the material to be heated is mainly made of stainless steel, the upper and lower arms 20 are driven. . Next, the operation of FIG. 15 will be described with reference to FIG. FIG. 16 shows waveforms when the upper and lower arms 10 and 20 are simultaneously driven.

Referring to FIG. 15 and FIG.
The voltages between the collector and the emitter of the IGBTs 11 and 13 of 0 are Va1 and Vb1, respectively. The current flowing through the IGBT 11 and the diode 12 is Ia1, and the current flowing through the IGBT 13 and the diode 14 is Ib1. The voltages between the collectors and the emitters of the IGBTs 21 and 23 of the upper and lower arms 20 are Va2 and Vb2, respectively. The current flowing through the upper arm diode 26 is Ia2, the capacitor 4
8 is Isa2, the current flowing through the lower arm diode 28 is Ib2, and the current flowing through the capacitor 49 is Isb2.

In FIG. 16, when the drive signals of the IGBTs 11 and 21 are turned on and the energy stored in the heating coil 5 becomes zero, the polarity of the resonance current IL5 changes from negative to positive,
A resonance current IL5 flows through a path of the IGBT 11, the heating coil 5, and the capacitor 6.

On the other hand, the resonance current IL flowing through the heating coil 7
7 has a negative polarity, and IL7 flows through the path of the IGBT 11, the heating coil 7, the diode 22, and the capacitor 48. When the energy stored in the heating coil 7 becomes zero, the polarity of the resonance current IL7 changes from negative to positive. At this time,
Since the voltage of the capacitor 48, that is, the voltage in the reverse direction, is applied to the diode 26 of the upper and lower arms 20, it does not conduct, and the resonance current IL 7 flows through the path of the capacitor 48, the IGBT 21, the heating coil 7, the heating coil 5, and the capacitor 6. .
When the electric charge of the capacitor 48 is exhausted and a forward voltage is applied to the diode 26, the resonance current IL7 changes to the diode 26, the IGBT 21, the heating coil 7, the heating coil 5,
It flows through the path of the capacitor 6.

Next, when the drive signals of the IGBTs 11 and 21 are turned off, the resonance current IL5 has a positive polarity.
The charge of the capacitor 17 and the capacitor 50 is discharged by L5, and then the resonance current IL5 is applied to the heating coil 7,
It flows through the path of the heating coil 5, the capacitor 6, the diode 24, and the capacitor 49.

Next, when the drive signals of the IGBTs 13 and 23 are turned on and the energy stored in the heating coil 5 becomes zero, the polarity of the resonance current IL5 changes from positive to negative, and the resonance current IL5 passes through the path of the capacitor 6, the heating coil 5 and the IGBT13. IL
5 flows.

On the other hand, the resonance current IL flowing through the heating coil 7
7 has a positive polarity, and IL7 is the heating coil 7, I
It flows through the path of the GBT 13, the diode 24, and the capacitor 49. When the energy stored in the heating coil 7 becomes zero, the polarity of the resonance current IL7 changes from positive to negative. At this time,
The voltage of the capacitor 49, that is, the reverse voltage is applied to the diode 28 of the upper and lower arms 20, so that the diode 28 does not conduct. Therefore, the resonance current IL7 flows through the path of the capacitor 6, the heating coil 5, the heating coil 7, the capacitor 49, and the IGBT 23. .
When the electric charge of the capacitor 49 is lost and a forward voltage is applied to the diode 28, the resonance current IL7 is changed to the capacitor 6, the heating coil 5, the heating coil 7, the diode 28,
It flows through the IGBT 23 path.

Next, when the drive signals of the IGBTs 13 and 23 are turned off, the resonance current IL5 has a negative polarity, and
The capacitor 17 and the capacitor 50 are charged by L5, and the resonance current IL5 is thereafter changed to the capacitor 6, the heating coil 5, the heating coil 7, the diode 22, and the capacitor 4.
It flows on the route of 8.

As described above, the high-frequency current can be supplied to the heating coil by repeating the above operation. In FIG. 15, the capacitor 50 is connected to the upper and lower arms 10.
May be divided and connected to the upper and lower arms. Further, the capacitor 19, the IGBT 18 and the diode 19 may be connected to the upper arm of the upper and lower arms 10.

In FIG. 16, the upper and lower arms 10 are turned on at the same time as the upper and lower arms 20, but the input power is adjusted by delaying the on timing from the upper and lower arms 20 and making the off timing earlier. Is possible.

The present embodiment is also applicable to the case where a high-resistance object to be heated is heated at a high output as described above.
In addition, since the upper and lower arms 20 are driven and currents of substantially the same phase are applied to both of the heating coils 5 and 7 for heating, both coils can be used effectively. In addition, since the resonance current IL5 flowing through the heating coil 5 is divided and flows into each of the upper and lower arms, the burden on each IGBT is reduced.

In the tenth embodiment, two upper and lower arms 10, 20 and two heating coils 5, 7 are shown. However, in order to diversify the material of the object to be heated, the upper and lower arms and the heating coil are provided. It is also possible to adopt an additional configuration.

An eleventh embodiment will be described with reference to FIG.

FIG. 17 is a circuit diagram of an electromagnetic induction heating apparatus according to an eleventh embodiment of the present invention.

The rectifier circuit and the smoothing circuit are omitted, and only the inverter section is shown. In addition, the same parts as those in FIG. 16 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 17, a reverse current blocking IGBT 32 is connected to the upper arm of the upper and lower arms 20, and a reverse current blocking IGBT 33 is connected to the lower arm.
A capacitor 40 and an IGBT 41 are connected in series to the upper arm, and a diode 42 is connected to the IGBT 41 in antiparallel. The lower arm has a capacitor 43 and I
GBTs 44 are connected in series, and a diode 45 is connected to the IGBTs 44 in anti-parallel.

In FIG. 17, the IGB of the upper and lower arms 20
T32 and IGBT41 and IGBT33 and IGBT44 are respectively controlled by the same drive signal. In the present embodiment, by performing the same control as in FIG. 15, even when a high-resistance object to be heated is heated at a high output, a current having substantially the same phase is applied to both of the heating coils 5 and 7 for heating. be able to.

In the eleventh embodiment, two upper and lower arms 10 and 20 and two heating coils 5 and 7 are shown. However, in order to diversify the material to be heated, the upper and lower arms and heating coil are provided. It is also possible to adopt an additional configuration.

A twelfth embodiment will be described with reference to FIG.

FIG. 18 shows a part of a circuit diagram of an electromagnetic induction heating apparatus according to a twelfth embodiment of the present invention.
Is connected to points s and t in the above embodiment.

As shown in FIG. 18, the capacitor 8 is provided between the point s and the heating coil 7. By connecting the capacitor 8 to the above embodiment, the capacitors are connected in series, and the combined capacitance of the resonance circuit is reduced.

Accordingly, the resonance frequency is increased by connecting the capacitor 8 to the resonance circuit, and the reduction of the resonance frequency caused by the increase in the number of turns of the heating coil can be suppressed. In the embodiment shown in FIG. 1, a similar effect can be obtained by providing a capacitor in series with the heating coil 9. Thus, by switching the arm to be driven, it is possible to simultaneously switch the number of turns of the heating coil and the capacitance value of the capacitor.

A thirteenth embodiment will be described with reference to FIG.

FIG. 19 is a plan view of a heating coil of an electromagnetic induction heating apparatus according to a thirteenth embodiment of the present invention.

In FIG. 19, the heating coils 5 and 7 each have a structure in which adjacent conductors are spirally wound. In FIG. 4, the heating coils 5 and 7 are arranged inside and outside, however, in this embodiment, the heating coils 5 and 7 are arranged at substantially the same position.

Therefore, when heating is performed using only the heating coil 5, the path length of the eddy current flowing through the object to be heated is longer than that in FIG. 4, and the heating area of the object to be heated can be increased. Efficiency can be increased.

In the embodiments described above, the input power can be adjusted by a method of changing the oscillation frequency of the inverter, a pulse width modulation for controlling the on / off period of the switching element, or a method combining these controls.

[0129]

According to the present invention, the number of windings of a heating coil can be switched with a simple configuration according to an object to be heated and a set output without using an expensive and large-sized relay having a large current capacity. And an electromagnetic induction heating device capable of efficiently supplying the electric power.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an electromagnetic induction heating device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between the number of turns of a heating coil and an equivalent resistance of the electromagnetic induction heating device according to the embodiment of FIG.

FIG. 3 is a circuit configuration diagram of an electromagnetic induction heating device according to a second embodiment of the present invention.

FIG. 4 is a plan view of a heating coil of the electromagnetic induction heating device according to the embodiment of FIG. 3;

FIG. 5 is a sectional view of a heating coil unit of the electromagnetic induction heating device according to the embodiment of FIG. 3;

FIG. 6 is an operation explanatory diagram in the embodiment of FIG. 3;

FIG. 7 is a structural sectional view of a heating coil unit of an electromagnetic induction heating device according to a third embodiment of the present invention.

FIG. 8 is a circuit diagram of an electromagnetic induction heating device according to a fourth embodiment of the present invention.

FIG. 9 is a circuit diagram of an electromagnetic induction heating device according to a fifth embodiment of the present invention.

FIG. 10 is a circuit diagram of an electromagnetic induction heating device according to a sixth embodiment of the present invention.

FIG. 11 is a circuit diagram of an electromagnetic induction heating device according to a seventh embodiment of the present invention.

FIG. 12 is a circuit diagram of an electromagnetic induction heating device according to an eighth embodiment of the present invention.

FIG. 13 is an operation explanatory diagram in the embodiment of FIG. 12;

FIG. 14 is a circuit diagram of an electromagnetic induction heating device according to a ninth embodiment of the present invention.

FIG. 15 is a circuit diagram of an electromagnetic induction heating device according to a tenth embodiment of the present invention.

FIG. 16 is an operation explanatory diagram in the embodiment of FIG. 15;

FIG. 17 is a circuit diagram of an electromagnetic induction heating device according to an eleventh embodiment of the present invention.

FIG. 18 is a diagram showing a part of a circuit diagram of an electromagnetic induction heating device according to a twelfth embodiment of the present invention.

FIG. 19 is a plan view of a heating coil of an electromagnetic induction heating device according to a thirteenth embodiment of the present invention.

FIG. 20 is a graph showing an equivalent impedance of a heated object in a conventional example.

FIG. 21 is a graph showing the relationship between input power and resonance current in a conventional example.

[Explanation of symbols]

1. Commercial AC power supply 2. Rectifier circuit 3. Inductor
4,6,8,15,16,17,29,31,39,4
0, 43, 48, 49, 50 ... capacitors, 5, 7, 9
... heating coil, 10, 20, 30 ... upper and lower arms 10a,
10b, 20a, 20b, 30a, 30b ... switching elements, 11, 13, 18, 21, 23, 25, 27,
32, 33, 34, 35, 36, 41, 44... Semiconductor switching elements, 12, 14, 19, 22, 24, 2
6, 28, 37, 38, 42, 45 ... diode, 60
... resonant circuit, 61, 62, 63, 64, 65 ... drive circuit, 70 ... control circuit, 71, 73 ... current detecting element, 7
2: Resonant current detection circuit, 74: Input current detection circuit, 75
... input power setting section, 80 ... coil support base, 81, 8
3, 84, 85, 86: magnetic material, 82: plate, 90
... an object to be heated, 100 ... an inverter.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Ryuji Iyoya             Hitachi, Ibaraki Pref.             Hitachi, Ltd., Hitachi Laboratory (72) Inventor Reiko Kanoda             Hitachi, Ibaraki Pref.             Hitachi, Ltd., Hitachi Laboratory (72) Inventor Masayuki Isogai             Chiba Prefecture Kashiwa City Shinjuyo 2-3-3 1 Nihon Co., Ltd.             Inside Ritsu Home Tech F term (reference) 3K059 AA03 AA07 AC07 AC15 AD03                       AD14 AD35 BD24 CD07

Claims (27)

[Claims] 1. A resonance circuit including an object to be heated, and an inverter for converting a DC voltage to an AC voltage and supplying power to the resonance circuit, wherein the inverter includes at least two switching elements connected in series. An electromagnetic induction heating apparatus having upper and lower arms, comprising: at least two or more upper and lower arms, wherein each of the upper and lower arms is in parallel with a (positive or negative) extreme of a DC power supply of the DC voltage And the output terminal is where the two switching elements are connected in series with each other. The resonance circuit is connected between the output terminal t of one upper and lower arm and at least one extreme of the DC power supply. And a heating capacitor forming the resonance circuit is connected between the output terminal t and the output terminal s of the other upper and lower arms. An electromagnetic induction heating apparatus comprising: a drive circuit for driving the switching elements of the upper and lower arms; and a control circuit for controlling the drive circuits. 2. A resonance circuit including an object to be heated, and an inverter for converting a DC voltage into an AC voltage and supplying power to the resonance circuit, wherein the inverter includes at least two switching elements connected in series. An electromagnetic induction heating device having an upper and lower arm comprising: a first and a second two upper and lower arms, wherein each of the upper and lower arms is extremely (positive or negative) of a DC power supply of the DC voltage. The output terminal t is where the two switching elements of the first upper and lower arms are connected in series with each other, and the two switching elements of the second upper and lower arms are connected in series with each other. The first heating coil and the first resonance capacitor constituting the resonance circuit are connected between the output terminal t and at least one extreme of the DC power supply. Continued, and first to connect the second heating coil constituting the resonant circuit between the output terminals s and the output terminal t, drives the switching elements of the first upper and lower arms
And a control circuit for controlling the first and second drive circuits, a second drive circuit for driving the switching element of the second upper and lower arms, and a control circuit for controlling the first and second drive circuits. 3. A resonance circuit including an object to be heated, and an inverter for converting a DC voltage to an AC voltage and supplying power to the resonance circuit, wherein the inverter includes at least two switching elements connected in series. In the electromagnetic induction heating apparatus having the upper and lower arms, the upper and lower arms are provided with first, second, and third three, and each of the upper and lower arms includes a DC power supply (positive and negative) of the DC voltage. )
The output terminal t is where the two switching elements of the first upper and lower arms are connected in series with each other, and the two switching elements of the second upper and lower arms are connected in series with each other. Is connected to the output terminal s, and the place where the two switching elements of the third upper and lower arms are connected in series is set as the output terminal a. And a first heating coil and a first resonance capacitor forming the resonance circuit are connected to each other, and a second heating coil forming the resonance circuit is formed between the output terminal t and the output terminal s. Connecting a third heating coil constituting the resonance circuit between the output terminal s and the output terminal a, and driving a switching element of the first upper and lower arms.
, A second drive circuit for driving the switching elements of the second upper and lower arms, a third drive circuit for driving the switching elements of the third upper and lower arms, and the first, second and third switches An electromagnetic induction heating device comprising a control circuit for controlling the drive circuit. 4. The electromagnetic induction heating apparatus according to claim 1, wherein a first current detecting element for detecting a current flowing in the resonance circuit, and a first current detecting element for detecting a current flowing in the resonance circuit. A resonance current detection circuit for converting an output signal level into a signal suitable for an input level of the control circuit; a second current detection element for detecting an input current supplied to each of the upper and lower arms; and a second current detection element An input current detection circuit for converting an output signal level of the input current signal into a signal suitable for an input level of the control circuit, wherein the control circuit responds to the output signals of the resonance current detection circuit and the input current detection circuit. An electromagnetic induction heating apparatus comprising: determining a material and a state of a heating object; selecting at least one drive circuit to be driven; and controlling operation thereof. 5. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit configured to set electric power to be supplied to the object to be heated, wherein the control circuit is configured to control the input power. An electromagnetic induction heating device, wherein at least one of the drive circuits to be driven is selected and the operation is controlled in accordance with an output signal from a power setting unit. 6. The electromagnetic induction heating device according to claim 1, wherein the switching elements of the upper and lower arms are power semiconductor switching elements, and the power semiconductor switching elements are diodes in antiparallel. An electromagnetic induction heating device, comprising: 7. The electromagnetic induction heating apparatus according to claim 1, wherein the switching element of the upper and lower arms is a power semiconductor switching element, the power semiconductor switching element includes a diode in anti-parallel, A second capacitor connected in series between at least one extreme of the DC power supply and a power semiconductor switching element; the power semiconductor switching element connected in series to the second capacitor includes a diode in antiparallel; A fourth drive circuit for driving the power semiconductor switching element connected in series to a second capacitor, wherein the control circuit controls the fourth drive circuit in conjunction with the drive circuit. Electromagnetic induction heating device. 8. The electromagnetic induction heating apparatus according to claim 1, wherein the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the first upper and lower arms 10 are connected in series. First and second power semiconductor switching elements 11 and 13 which are connected in anti-parallel, respectively, to the first and second diodes 12 and 1.
The upper arm of the second upper and lower arm 20 includes a third diode 26 and a third power semiconductor switching element 21 connected in series, and the third power semiconductor switching element 21 is connected in anti-parallel. A fourth diode 22;
The third diode 26 includes a fourth power semiconductor switching element 25 in anti-parallel, and the lower arm of the second upper and lower arms 20 includes a fifth diode 28 and a fifth power semiconductor switching element connected in series. 23, and the fifth power semiconductor switching element 23 includes a sixth diode 24 in anti-parallel, the fifth diode 28 includes a sixth power semiconductor switching element 27 in anti-parallel, And sixth power semiconductor switching element 2
And a fifth drive circuit for driving the fifth and fifth drive circuits, and wherein the control circuit controls the fifth drive circuit in conjunction with the first to third drive circuits. . 9. The electromagnetic induction heating apparatus according to claim 8, wherein the third power semiconductor switching element includes a third capacitor in parallel, and the fifth power semiconductor switching element includes a fourth capacitor in parallel. An electromagnetic induction heating device comprising: 10. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit for setting power to be supplied to the object to be heated, wherein the control circuit controls an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, and the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20. Are first and second connected in series.
And the first and second power semiconductor switching elements 11, 1
3 is a first and a second diode 1 which are respectively anti-parallel.
2 and 14, wherein the second upper and lower arms 20 have first and second power semiconductor switching elements 32 and 33 having a reverse withstand voltage function, and the second upper and lower arms 20 are provided on at least one of the upper and lower arms. A second capacitor 43 and a power semiconductor switching element 44 connected in series, and the power semiconductor switching element 44 includes a diode 45 in anti-parallel, and a fourth driving the power semiconductor switching element 44
The electromagnetic induction heating device, further comprising: a drive circuit 65 for controlling the fourth drive circuit 65 in cooperation with the drive circuit. 11. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit for setting power to be supplied to the object to be heated, wherein the control circuit outputs an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, and the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the first upper and lower arms 10 has first and second power semiconductor switching elements 11 and 13;
The second power semiconductor switching elements 11 and 13 are respectively provided with first and second diodes 12 and 14 in antiparallel, and the second upper and lower arms 20 are provided with first and second power semiconductor switching devices having reverse withstand voltage functions. Having elements 32 and 33,
The first and second power semiconductor switching elements with reverse withstand voltage function include third and fourth power semiconductor switching elements with reverse withstand voltage function in antiparallel, respectively, and the second power with switching function with reverse withstand voltage function. An electromagnetic induction heating apparatus, comprising: a fifth drive circuit for driving a semiconductor switching element 33; wherein the control circuit 70 controls the fifth drive circuit in conjunction with the drive circuit. 12. The electromagnetic induction heating apparatus according to claim 11, wherein the second upper and lower arms have a second capacitor and a power semiconductor switching element connected in series to at least one of the upper and lower arms. And the power semiconductor switching element 44 includes a diode 45 in anti-parallel,
The electromagnetic induction heating device, further comprising: a drive circuit 65 for controlling the fourth drive circuit 65 in cooperation with the drive circuit. 13. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit that sets power to be supplied to the object to be heated, wherein the control circuit outputs an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, and the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the first upper and lower arms 10 has first and second power semiconductor switching elements 11 and 13;
The second power semiconductor switching elements 11 and 13 are respectively provided with first and second diodes 12 and 14 in antiparallel, and the second upper and lower arms 20 are provided with first and second power semiconductor switching devices having reverse withstand voltage functions. Having elements 32 and 33,
One of the first and second power semiconductor switching elements 32 and 33 having reverse withstand voltage function is connected in anti-parallel to the fifth power semiconductor switching element.
And the other of the first and second power semiconductor switching elements 32 and 33 having a reverse withstand voltage function is a seventh diode 37 and an eighth diode which are connected in anti-series. 38, the seventh diode 37 includes a seventh power semiconductor switching element 36 in anti-parallel, and the eighth diode 38 includes a fifth capacitor 3 in parallel.
9, the fifth power semiconductor switching element 34 with reverse withstand voltage function and the seventh power semiconductor switching element 36.
A fifth drive circuit for driving the control circuit;
Numeral 0 controls the fifth drive circuit in conjunction with the drive circuit. 14. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit for setting power to be supplied to the object to be heated, wherein the control circuit outputs an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, and the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the first upper and lower arms 10 has first and second power semiconductor switching elements 11 and 13;
The second power semiconductor switching elements 11 and 13 include first and second diodes 12 and 14 in anti-parallel, respectively. The upper arm of the second upper and lower arms 20 is connected to a third diode 26 connected in series with a third diode 26. And the third power semiconductor switching element 21 includes a fourth diode 22 in anti-parallel, and the lower arm of the second upper and lower arm 20 is connected to a fifth A diode 28 and a fifth power semiconductor switching element 23, and the fifth power semiconductor switching element 23 includes a sixth diode 24 in antiparallel, and the second upper and lower arms 20 are at least one of an upper and lower arm A second capacitor 43 and a power semiconductor switching element 44 connected in series to the power semiconductor switch; Grayed element 44 includes a diode 45 in inverse parallel, fourth for driving the power semiconductor switching element 44
An electromagnetic induction heating apparatus, comprising: a drive circuit 65 for controlling the fourth drive circuit 65 in cooperation with the drive circuit. 15. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit for setting power to be supplied to the object to be heated, wherein the control circuit outputs an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, and the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the first upper and lower arms 10 has first and second power semiconductor switching elements 11 and 13;
The second power semiconductor switching elements 11 and 13 include first and second diodes 12 and 14 in anti-parallel, respectively. The upper arm of the second upper and lower arms 20 is connected to a third diode 26 connected in series with a third diode 26. And the third power semiconductor switching element 21 includes a fourth diode 22 in anti-parallel, the third diode 26 includes a sixth capacitor 48 in parallel, The lower arm of the two upper and lower arms 20 includes a fifth diode 28 and a fifth power semiconductor switching element 23 connected in series, and the fifth power semiconductor switching element 23 has a sixth diode 24 connected in anti-parallel. The fifth diode 28 includes a seventh capacitor 49 in parallel, and the second upper and lower arms 20 include at least one Electromagnetic induction heating device characterized by the arm comprising a capacitor 50 of the eighth. 16. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit for setting power to be supplied to the object to be heated, wherein the control circuit outputs an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, and the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the first upper and lower arms 10 has first and second power semiconductor switching elements 11 and 13;
The second power semiconductor switching elements 11 and 13 are respectively provided with first and second diodes 12 and 14 in antiparallel, and the second upper and lower arms 20 are provided with first and second power semiconductor switching devices having reverse withstand voltage functions. Having elements 32 and 33,
The second upper and lower arms 20 include capacitors 40 and 43 connected in series and power semiconductor switching elements 41 and
44, and the power semiconductor switching element 41,
44 includes diodes 42 and 45 in anti-parallel, the second upper and lower arms 20 include an eighth capacitor 50 in at least one arm, and a fifth driving the power semiconductor switching element 41.
An electromagnetic induction heating apparatus, comprising: a drive circuit for controlling the fifth drive circuit in conjunction with the drive circuit. 17. The electromagnetic induction heating apparatus according to claim 1, wherein the first upper and lower arms have at least one of a ninth capacitor and a ninth capacitor. 18. The electromagnetic induction heating apparatus according to claim 1, wherein the first upper and lower arms include a tenth capacitor and a power semiconductor switching element connected in series to at least one of the arms. The power semiconductor switching element 18 includes a diode 19 in anti-parallel, and a sixth driving the power semiconductor switching element 18
An electromagnetic induction heating apparatus, comprising: a drive circuit 64 of the first embodiment; and the control circuit 70 controls the sixth drive circuit. 19. The electromagnetic induction heating apparatus according to claim 1, further comprising a resonance capacitor connected in series to the heating coil, in addition to the resonance capacitor. Electromagnetic induction heating device. 20. The electromagnetic induction heating apparatus according to claim 1, wherein the first, second, and third heating coils are formed of a spirally wound conductor. An electromagnetic induction heating apparatus, wherein the first, second, and third ranks are arranged so as to be closer to the outer periphery as they come later, and provided so as to be closer to the object to be heated. 21. The electromagnetic induction heating apparatus according to claim 20, wherein the heating coil includes a magnetic body on a side opposite to the object to be heated. 22. The electromagnetic induction heating device according to claim 21, wherein the magnetic material is individually divided corresponding to the first, second, and third heating coils. Electromagnetic induction heating device. 23. The electromagnetic induction heating device according to claim 22, wherein a magnetic material for isolation is provided between the inner and outer peripheries adjacent to the first, second, and third heating coils. Wherein the magnetic body is in close contact with an outer peripheral end side or an inner peripheral end side of the divided magnetic body. 24. The electromagnetic induction heating apparatus according to claim 23, further comprising a magnetic material for isolation on an outer periphery of the heating coil disposed at an outermost periphery, wherein the magnetic material for isolation and the magnetic material for isolation are provided. An electromagnetic induction heating apparatus characterized in that the divided magnetic body is in close contact with the outer peripheral end side. 25. The electromagnetic induction heating device according to claim 1, wherein the first, second, and third heating coils are formed of a spirally wound conductor. An electromagnetic induction heating apparatus, wherein each of the conductors of the heating coil is arranged adjacent to each other and is provided so as to be close to the object to be heated. 26. The electromagnetic induction heating apparatus according to claim 1, wherein the first, second, and third heating coils are on the side opposite to the object to be heated. An electromagnetic induction heating device comprising a magnetic material. 27. The electromagnetic induction heating apparatus according to claim 1, further comprising: an input power setting unit for setting power to be supplied to the object to be heated, wherein the control circuit controls an output signal from the input power setting unit. Accordingly, the operation is controlled by selecting at least one of the drive circuits to be driven, wherein the upper and lower arms have at least a first upper and lower arm 10 and a second upper and lower arm 20, and the second upper and lower arms 20. An electromagnetic induction heating apparatus, wherein the output voltage of the DC power supply is higher than the DC voltage of the DC power supply.