JP6931792B2 - Induction heating device and its drive control method - Google Patents

Description

The present disclosure relates to an induction heating device capable of simultaneously driving a plurality of inverters by supplying electric power from the same power source, and a drive control method thereof.

In the conventional induction heating device, as a configuration for simultaneously driving a plurality of inverters by supplying electric power from the same power source, for example, there is an induction heating cooker described in Patent Document 1. The induction heating cooker of Patent Document 1 is configured to alternately drive two inverters by changing the operation pattern by supplying electric power from one power source, and simultaneously perform induction heating cooking by two heating coils. The induction heating cooker of Patent Document 1 has a configuration in which an input current value from a power source is detected, and the detected current value is a total value of current values flowing through two heating coils. Therefore, in the induction heating cooker of Patent Document 1, in order to control each heating coil, the drive frequency or conduction ratio of one inverter having a small input power is kept constant, and the current value detected by the input current detection circuit at that time is fixed. Based on the above, the drive frequency or the conduction ratio of the other inverter was controlled.

As described above, in the induction heating cooker of Patent Document 1, the operation pattern is changed to fix the drive frequency or the conduction ratio of one inverter having a small input power, and the heating coil controlled by the other inverter is used. Only in the case, the feedback control was performed based on the current value detected at that time.

Japanese Patent No. 5909675

In recent years, induction heating devices have been commercialized as cooking utensils capable of heating and cooking, for example, configurations that can handle metals with low resistance and low magnetic permeability such as aluminum pans and copper pans, and heat such cooking utensils. Since the Q value indicating the sharpness of the resonance peak is high, the drive frequency of the inverter is specified in a narrow frequency band. Further, in the induction heating device, a system has been proposed in which a heating coil is used as a feeding coil to supply electric power to an electric device (non-contact device) in a non-contact manner. In such a system that supplies power in a non-contact manner, a change in the resonance point, the Q value, and the coupling coefficient k indicating the degree of magnetic coupling between the feeding coil and the receiving coil due to the displacement of the positional relationship between the feeding coil and the receiving coil. Therefore, the drive frequency of the inverter is specified in a narrow frequency band, and the drive frequency band is shifted.

As described above, devices with different drive frequencies, that is, induction heating cookers that support normal induction heating such as iron pots, and non-contact devices, or cookware that can be driven in a specific frequency band with a narrow drive frequency (for example, , Aluminum pot, copper pot), etc., which have a high Q value, can be operated simultaneously by driving multiple inverters by supplying power from the same rectified power source, which is difficult with the configuration of a conventional induction heating device. there were. In particular, in the configuration of a conventional induction heating cooker that controls the other inverter by changing the operation pattern to fix the drive frequency or conduction ratio of one inverter with a small input power, the frequency control difference of each inverter is large. Since it is indefinite, synchronization cannot be achieved, the power fluctuation value for each drive cycle of each inverter becomes large, and it is very difficult to perform highly accurate feedback control for each inverter.

In the present disclosure, in an induction heating device that drives a plurality of inverters by supplying power from the same rectified power source, the Q value is high with induction heating, and the magnetic coupling coefficient k is particularly high for each device having a different drive frequency. It is an object of the present invention to provide an induction heating device and a drive control method for the induction heating device, which can be efficiently operated in a desired state even for a device in which the value changes.

The induction heating device of one aspect in the present disclosure is
A DC power supply circuit that outputs a DC voltage,
A plurality of inverters to which power is supplied from the DC power supply circuit, and
A plurality of coils formed by driving the plurality of inverters to which high-frequency currents are supplied, and
A control unit that detects a change in an electric signal in the DC power supply circuit due to the drive of the plurality of inverters, detects power supplied to the plurality of inverters, and controls a drive signal for driving the plurality of inverters. With
The control unit
The drive signal for driving one of the plurality of inverters is controlled so that the drive cycle is linked according to the drive signal for driving the other inverter.
The current paths from the DC power supply circuit to the plurality of inverters are simultaneously opened to form a drive signal in which the storage operation period in which the DC power supply circuit is in the storage state has a predetermined time interval.
It is configured to detect the total power supplied to the plurality of inverters based on the change in the electric signal of the DC power supply circuit during the storage operation period.

The drive control method of the induction heating device of one aspect in the present disclosure is described.
A DC power supply circuit that outputs a DC voltage,
A plurality of inverters to which power is supplied from the DC power supply circuit, and
A plurality of coils formed by driving the plurality of inverters to which high-frequency currents are supplied, and
A control unit that detects a change in an electric signal in the DC power supply circuit due to the drive of the plurality of inverters, detects power supplied to the plurality of inverters, and controls a drive signal for driving the plurality of inverters. It is a drive control method of an induction heating device equipped with
The drive signal that drives one inverter in the plurality of inverters interlocks the drive cycle according to the drive signal that drives the other inverter.
The current paths from the DC power supply circuit to the plurality of inverters are simultaneously opened to form a drive signal in which the storage operation period in which the DC power supply circuit is in the power storage state has a predetermined time interval, and the power storage is performed. It has a step of detecting the total power supplied to the plurality of inverters based on the change of the electric signal of the DC power supply circuit during the operation period.

The drive control method of the induction heating device of another aspect in the present disclosure is described.
A DC power supply circuit that outputs a DC voltage,
A first inverter to which power is supplied from the DC power supply circuit to form a first high-frequency current, and
A second inverter to which power is supplied from the DC power supply circuit to form a second high-frequency current, and
A first coil that generates a first high-frequency magnetic field by supplying a first high-frequency current from the first inverter, and
A second coil that generates a second high-frequency magnetic field by supplying a second high-frequency current from the second inverter, and
A drive control method for an induction heating device including a control unit that outputs a drive signal for driving and controlling the first inverter and the second inverter.
Detecting an electric signal that changes in the DC power supply circuit by driving the first inverter and the second inverter,
When the first inverter and the second inverter are simultaneously driven and controlled by the control unit, the drive cycle of the first inverter becomes n times or 1 / n times (n is a natural number) the drive cycle of the second inverter. Set,
With the power supplied to the first inverter based on the electric signal detected in a specific period of the drive signal in which the current path from the DC power supply circuit to the first inverter and the second inverter is simultaneously open. It has a step of calculating the total value of the electric power supplied to the second inverter.

In the induction heating device and its drive control method in the present disclosure, in a configuration in which a plurality of inverters are driven by power supply from the same rectified power source, induction heating is performed and each device having a different drive frequency is driven at the same time. In this case, it is possible to perform highly accurate feedback control for each inverter, and it is possible to efficiently operate each device to be driven in a desired state.

The control block diagram which shows the structure of the induction heating apparatus of Embodiment 1 which concerns on this disclosure. An example of a frequency characteristic diagram showing the relationship between the frequency of the high-frequency current flowing through the coil and the maximum power. In the induction heating device of the first embodiment, the frequency characteristic diagram which shows the feeding characteristic at the time of performing the feeding operation with respect to the non-contact feeding load. The figure which shows the discrimination method in the load discrimination operation Waveform diagram showing the operation of each inverter and each coil in the simultaneous drive mode in the induction heating device of the first embodiment. Waveform diagram showing an example of a drive signal supplied to each inverter in a single drive mode and a simultaneous drive mode in the induction heating device of the first embodiment. A waveform diagram showing the timing of the AD conversion for performing the first inverter, the second inverter, and the power detection in the simultaneous drive mode in the induction heating device of the first embodiment. The figure which shows typically the current flow in each operation period of the 1st inverter and the 2nd inverter in the induction heating apparatus of Embodiment 1. A flowchart showing an operation in the induction heating apparatus of the first embodiment when heating an induction heating load by driving one of the inverters. A flowchart showing the operation of the induction heating mode / non-contact power feeding mode driven by the second inverter in the induction heating device of the first embodiment. The control block diagram which shows the structure of the induction heating apparatus of Embodiment 2 which concerns on this disclosure. A flowchart showing an operation when the induction heating device of the second embodiment heats an induction heating load by driving a first inverter 3 as one of the inverters. In the induction heating device of the second embodiment, a flowchart in which one of the operation modes of the induction heating mode driven by the second inverter, the non-contact power supply mode, and the low resistance induction heating mode is selected and operated. In the induction heating device of the second embodiment, a flowchart in which one of the operation modes of the induction heating mode driven by the second inverter, the non-contact power supply mode, and the low resistance induction heating mode is selected and operated.

The induction heating device of the first aspect according to the present disclosure is
A DC power supply circuit that outputs a DC voltage,
A plurality of inverters to which power is supplied from the DC power supply circuit, and
A plurality of coils formed by driving the plurality of inverters to which high-frequency currents are supplied, and
A control unit that detects a change in an electric signal in the DC power supply circuit due to the drive of the plurality of inverters, detects power supplied to the plurality of inverters, and controls a drive signal for driving the plurality of inverters. With
The control unit
The drive signal for driving one of the plurality of inverters is controlled so that the drive cycle is linked according to the drive signal for driving the other inverter.
The current paths from the DC power supply circuit to the plurality of inverters are simultaneously opened to form a drive signal in which the storage operation period in which the DC power supply circuit is in the storage state has a predetermined time interval.
It is configured to detect the total power supplied to the plurality of inverters based on the change in the electric signal of the DC power supply circuit during the storage operation period.

The induction heating device of the first aspect configured as described above performs induction heating in a configuration in which a plurality of inverters are driven by power supply from the same power source, and simultaneously drives devices having different drive frequencies. In this case, it is possible to perform highly accurate feedback control for each inverter, and it is possible to efficiently operate each device to be driven in a desired state.

In the induction heating device of the second aspect according to the present disclosure, the control unit in the first aspect of the DC power supply circuit has an operation period other than the storage operation period of the drive signals for driving the plurality of inverters. The electric power supplied to each of the plurality of inverters may be calculated from the total electric power based on the change of the electric signal.

In the induction heating device of the third aspect according to the present disclosure, in the first or second aspect, the plurality of inverters include a first inverter and a second inverter, and the high frequency current from the first inverter is the same. It has a configuration in which a high frequency current is supplied to the first coil of a plurality of coils and a high frequency current from the second inverter is supplied to the second coil of the plurality of coils.
In the simultaneous drive of the first inverter and the second inverter, the control unit sets the drive cycle of the first inverter to n times or 1 / n times the drive cycle of the second inverter (n is a natural number). It may be configured as follows.

The induction heating device of the fourth aspect according to the present disclosure includes a low-pass filter in which the DC power supply circuit has an inductor and a capacitor in the third aspect.
The first inverter and the second inverter are connected in parallel to the output side of the low-pass filter.
The control unit
In the storage operation period in which the period in which the current path from the capacitor to the first inverter is open and the period in which the current path from the capacitor to the second inverter is open overlap, the voltage across the capacitor is staggered. It may be configured to detect twice and calculate the total power supplied from the DC power supply circuit to the first inverter and the second inverter based on the results of the two detections.

In the induction heating device of the fifth aspect according to the present disclosure, in the fourth aspect described above, a load that does not require selection of a drive frequency is driven by the first inverter, and a load that requires selection of a drive frequency is applied. In the state of being driven by the second inverter
The control unit
The voltage across the capacitor is detected at the timing when the current path from the capacitor to the first inverter changes from the open path to the closed path and when the current path from the capacitor to the second inverter changes from the closed path to the open path. Then, it may be configured to calculate the electric power supplied to the second inverter.

In the induction heating device of the sixth aspect according to the present disclosure, the calculation result of the electric power supplied to the second inverter by the control unit in the fifth aspect, and the total electric power supplied to the plurality of inverters. May be configured to calculate the power supplied to the first inverter based on.

The drive control method for the induction heating device according to the seventh aspect according to the present disclosure is as follows.
A DC power supply circuit that outputs a DC voltage,
A plurality of inverters to which power is supplied from the DC power supply circuit, and
A plurality of coils formed by driving the plurality of inverters to which high-frequency currents are supplied, and
A control unit that detects a change in an electric signal in the DC power supply circuit due to the drive of the plurality of inverters, detects power supplied to the plurality of inverters, and controls a drive signal for driving the plurality of inverters. It is a drive control method of an induction heating device equipped with
The drive signal that drives one inverter in the plurality of inverters interlocks the drive cycle according to the drive signal that drives the other inverter.
The current paths from the DC power supply circuit to the plurality of inverters are simultaneously opened to form a drive signal in which the storage operation period in which the DC power supply circuit is in the power storage state has a predetermined time interval, and the power storage is performed. It has a step of detecting the total power supplied to the plurality of inverters based on the change of the electric signal of the DC power supply circuit during the operation period.

The drive control method of the induction heating device of the seventh aspect configured as described above is to drive a plurality of inverters by supplying electric power from the same power source to perform induction heating, and at the same time, each device having a different drive frequency. In the case of driving the inverter, it is possible to perform highly accurate feedback control for each inverter, and each device to be driven can be operated efficiently in a desired state.

The drive control method for the induction heating device according to the eighth aspect according to the present disclosure is, in the seventh aspect, the electricity of the DC power supply circuit in an operation period other than the storage operation period in the drive signals for driving the plurality of inverters. It may include a step of calculating the electric power supplied to each of the plurality of inverters from the total electric power based on the change of the signal.

In the drive control method of the induction heating device according to the ninth aspect according to the present disclosure, in the seventh or eighth aspect, the plurality of inverters include a first inverter and a second inverter, and the first inverter is used. A drive control method for an induction heating device having a configuration in which a high-frequency current is supplied to the first coil of the plurality of coils and a high-frequency current from the second inverter is supplied to the second coil of the plurality of coils.
In the simultaneous drive of the first inverter and the second inverter, the drive cycle of the first inverter is set to n times or 1 / n times (n is a natural number) of the drive cycle of the second inverter, including a step. It may be.

The drive control method of the induction heating device according to the tenth aspect according to the present disclosure is the method of the ninth aspect, wherein the DC power supply circuit includes a low-pass filter having an inductor and a capacitor, and the output side of the low-pass filter is the same. This is a drive control method for an induction heating device in which a first inverter and the second inverter are connected in parallel.
In the storage operation period in which the period in which the current path from the capacitor to the first inverter is open and the period in which the current path from the capacitor to the second inverter is open overlap, the voltage across the capacitor is staggered. It may include a step of detecting twice and calculating the total power supplied from the DC power supply circuit to the first inverter and the second inverter based on the results of the two detections.

In the drive control method of the induction heating device according to the eleventh aspect according to the present disclosure, in the tenth aspect, a load that does not need to select a drive frequency is driven by the first inverter, and the drive frequency needs to be selected. In a state where a certain load is driven by the second inverter
The voltage across the capacitor is detected at the timing when the current path from the capacitor to the first inverter changes from the open path to the closed path and when the current path from the capacitor to the second inverter changes from the closed path to the open path. Then, the step of calculating the electric power supplied to the second inverter may be included.

The drive control method for the induction heating device according to the twelfth aspect according to the present disclosure is the calculation result of the electric power supplied to the second inverter and the total electric power supplied to the plurality of inverters in the eleventh aspect. It may include a step of calculating the electric power supplied to the first inverter based on the above.

The drive control method for the induction heating device according to the thirteenth aspect according to the present disclosure is as follows.
A DC power supply circuit that outputs a DC voltage,
A first inverter to which power is supplied from the DC power supply circuit to form a first high-frequency current, and
A second inverter to which power is supplied from the DC power supply circuit to form a second high-frequency current, and
A first coil that generates a first high-frequency magnetic field by supplying a first high-frequency current from the first inverter, and
A second coil that generates a second high-frequency magnetic field by supplying a second high-frequency current from the second inverter, and
A drive control method for an induction heating device including a control unit that outputs a drive signal for driving and controlling the first inverter and the second inverter.
Detecting an electric signal that changes in the DC power supply circuit by driving the first inverter and the second inverter,
When the first inverter and the second inverter are simultaneously driven and controlled by the control unit, the drive cycle of the first inverter becomes n times or 1 / n times (n is a natural number) the drive cycle of the second inverter. Set,
With the power supplied to the first inverter based on the electric signal detected in a specific period of the drive signal in which the current path from the DC power supply circuit to the first inverter and the second inverter is simultaneously open. It has a step of calculating the total value of the electric power supplied to the second inverter.

The drive control method of the induction heating device according to the thirteenth aspect configured as described above is for each device having a different drive frequency in the induction heating device that drives a plurality of inverters by supplying electric power from the same power source. In particular, it is possible to efficiently operate a device having a large Q value in a desired state.

The drive control method for the induction heating device according to the fourteenth aspect according to the present disclosure is the drive cycle of the first inverter when the first inverter is driven independently and the first inverter in the thirteenth aspect. And when the second inverter is driven at the same time, the drive cycle of the first inverter may be different.

The drive control method for the induction heating device according to the fifteenth aspect according to the present disclosure is when the drive of the second inverter is started while the first inverter in the thirteenth or fourteenth aspect is being driven independently. Based on the drive cycle of the second inverter, the drive cycle of the first inverter may be changed from the drive cycle when the first inverter was driven independently.

The drive control method for the induction heating device according to the sixteenth aspect according to the present disclosure starts driving the second inverter while the first inverter in any one of the thirteenth to fifteenth aspects is being driven independently. At that time, the drive of the first inverter may be temporarily stopped.

The drive control method for the induction heating device according to the seventeenth aspect according to the present disclosure is a case where the drive of the second inverter is started while the first inverter in the sixteenth aspect is operating alone in the induction heating mode. When the drive cycle selection operation of sweeping the second inverter with a drive signal having a lower current than usual is executed to select the drive cycle of the second inverter, the drive of the first inverter is temporarily driven. You may stop.

The drive control method for the induction heating device according to the eighteenth aspect according to the present disclosure is the first method when the drive cycle of the second inverter in the seventeenth aspect is selected and the drive of the second inverter is started. 1 The operation of the inverter may be restarted.

The drive control method for the induction heating device according to the nineteenth aspect according to the present disclosure is the second aspect of the method, wherein the first inverter and the second inverter are operating at the same time in any of the thirteenth to eighteenth aspects. When the drive of the inverter is stopped, the drive cycle of the first inverter may be changed to the drive cycle when the first inverter is driven independently.

The drive control method for the induction heating device according to the twentieth aspect according to the present disclosure is the second high frequency generated in the second coil by driving the second inverter in any one of the thirteenth to nineteenth aspects. A magnetic field may be used to feed the non-contact feed load or to heat a low resistance induction heating load.

The drive control method of the induction heating device according to the twenty-first aspect according to the present disclosure is the method of operating the second inverter in the non-contact power feeding mode or in the induction heating mode in any one of the thirteenth to twenty-second aspects. Includes more steps to choose whether to work,
When the non-contact power supply mode is selected, the drive cycle of the first inverter when the first inverter is driven independently and the first inverter when the first inverter and the second inverter are driven at the same time. The drive cycle of the inverter may be different.

In the drive control method of the induction heating device according to the 22nd aspect according to the present disclosure, in any one of the 13th to 21st aspects, the DC power supply circuit includes a low-pass filter composed of an inductor and a capacitor. A drive control method for an induction heating device in which the first inverter and the second inverter are connected in parallel on the output side of the low-pass filter.
The voltage applied to the capacitor is detected and
In the storage operation period in which the period in which the current path from the capacitor to the first inverter is open and the period in which the current path from the capacitor to the second inverter is open overlap, the voltage across the capacitor is staggered. It may include a step of detecting twice and calculating the total power supplied from the DC power supply circuit to the first inverter and the second inverter based on the results of the two detections.

In the drive control method of the induction heating device according to the 23rd aspect according to the present disclosure, in the 22nd aspect, a load that does not need to select a drive frequency is driven by the first inverter, and the drive frequency needs to be selected. In a state where a certain load is driven by the second inverter
The voltage across the capacitor is detected at the timing when the current path from the capacitor to the first inverter changes from the open path to the closed path and when the current path from the capacitor to the second inverter changes from the closed path to the open path. Then, the step of calculating the electric power supplied to the second inverter may be included.

The drive control method for the induction heating device according to the 24th aspect according to the present disclosure is the calculation result of the electric power supplied to the second inverter and the total electric power supplied to the plurality of inverters in the 22nd aspect. It may include a step of calculating the electric power supplied to the first inverter based on the above.

Hereinafter, an embodiment of the induction heating device and its drive control method according to the present disclosure will be described in detail with reference to the drawings as appropriate. In the description of the embodiment, for example, a detailed description of already well-known matters and a duplicate description for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art.

It should be noted that the inventor intends to limit the subject matter described in the claims by those skilled in the art by providing the accompanying drawings and the following description in order to fully understand the present disclosure. is not it.

In the following embodiments, a specific configuration of the induction heating device will be described, but this configuration is an example, and the present disclosure is not limited to the configurations described in the following embodiments. It includes an induction heating device having the disclosed technical features. Further, the present disclosure includes appropriately combining arbitrary configurations described in the respective embodiments described below, and the combined configurations exert their respective effects.

(Embodiment 1)
The induction heating device of the present disclosure has a configuration capable of heating an ordinary induction heating cooker (for example, an iron pot or the like: an induction heating load IH) that supports ordinary induction heating, has a high Q value, and has a feeding coil depending on the mounting position. Non-contact electric equipment (non-contact equipment: non-contact power supply), which is a load that requires selection of the drive cycle of the inverter because the coupling coefficient k, which indicates the degree of magnetic coupling between the power receiving coil and the power receiving coil, changes and the power receiving characteristics change significantly. Induction heating appliances with low resistance and high Q value (eg, aluminum pot, copper pot: low resistance induction) that can supply power to the load PS) and / or can be driven in a specific narrow frequency band. It is configured to be able to heat with respect to the heating load IHx). However, the induction heating device of the first embodiment has a configuration capable of heating an induction heating load IH corresponding to normal induction heating, and also for a non-contact power supply load PS, which is a load that requires selection of an inverter drive cycle. The configuration that can supply power will be described.

The induction heating device of the first embodiment described below has a configuration in which two inverters can be simultaneously driven at different frequencies by supplying electric power from the same rectified power source. In the induction heating device of the first embodiment, one inverter induces and heats a normal induction heating cookware (induction heating load IH), and the other inverter feeds a non-contact device (non-contact power supply load PS) at the same time. The case of the mode will be described. In the induction heating device of the first embodiment, there are a single drive mode in which each inverter is driven independently, and a simultaneous drive mode in which each inverter is driven so as to simultaneously heat a normal induction heating load IH. It is also possible to do it.

In the induction heating device of the first embodiment, a configuration in which two inverters are driven by power supply from the same rectified power source to excite each of the two coils will be described. In a configuration in which a plurality of inverters are driven by power supply from the same rectified power supply and a plurality of coils are excited by each inverter, the same technical features are applied and the same effect is achieved. be able to.

FIG. 1 is a control block diagram showing the configuration of the induction heating device according to the first embodiment. As shown in FIG. 1, the induction heating device of the first embodiment includes an AC power supply 1 and a DC power supply circuit 2 that rectifies AC from the AC power supply 1 and outputs a DC voltage. The DC power supply circuit 2 includes a diode bridge 9, a rectifying inductor 10, a rectifying capacitor 11, and an input voltage detecting unit 12. In the DC power supply circuit 2, a low-pass filter is configured by the rectifying inductor 10 and the rectifying capacitor 11. The input voltage detection unit 12 detects the voltage across the rectifier capacitor 11 and outputs a detection signal to the power calculation unit 15 of the control unit 13, which will be described later.

The DC voltage output from the DC power supply circuit 2 is converted into a desired high frequency voltage in the first inverter 3 and the second inverter 4, which are two inverter circuits, and is supplied to the first coil 5 and the second coil 6. .. That is, the first inverter 3 converts the DC power supply output from the DC power supply circuit 2 into a desired high frequency voltage, and the converted high frequency voltage is a resonance including the first coil 5 and the first resonance capacitor 7. Supplied to the circuit. Similarly, the second inverter 4 converts the DC power supply output from the DC power supply circuit 2 into a desired high frequency voltage, and the converted high frequency voltage becomes a resonance circuit composed of the second coil 6 and the second resonance capacitor 8. Be supplied.

The first inverter 3 is composed of a series connection of two semiconductor switches 3a and 3b, and the series connection of the two semiconductor switches 3a and 3b is connected in parallel to the rectifying capacitor 11 on the power supply side. Similarly, the second inverter 4 is composed of a series connection of two semiconductor switches 4a and 4b, and the series connection of the two semiconductor switches 4a and 4b is connected in parallel to the rectifier capacitor 11 on the power supply side. There is.

Each of the semiconductor switches 3a, 3b, 4a, and 4b in the first embodiment is composed of a power semiconductor (semiconductor switch element) such as an IGBT and a diode connected in parallel to the power semiconductor in the opposite direction.

In the following description, in the two semiconductor switches 3a and 3b in the first inverter 3 and the two semiconductor switches 4a and 4b in the second inverter 4, the semiconductor switches 3a and 4a on the high potential side are referred to as the high potential side switches 3a and 4a. The low-potential side semiconductor switches 3b and 4b are referred to as low-potential side switches 3b and 4b.

As shown in FIG. 1, a resonance circuit including the first coil 5 and the first resonance capacitor 7 is connected to both ends of the low potential side switch 3b in the first inverter 3. The first coil 5 is excited by the first inverter 3 and functions as a heating coil or a feeding coil. A snubber capacitor 17 having a function of suppressing the generation of a surge voltage at the time of on / off is provided at both ends of the low potential side switch 3b.

On the other hand, a resonance circuit including the second coil 6 and the second resonance capacitor 8 is connected to both ends of the low potential side switch 4b in the second inverter 4. The second coil 6 is excited by the second inverter 4 and functions as a heating coil or a feeding coil. A snubber capacitor 18 having a function of suppressing the generation of a surge voltage at the time of on / off (operation timing for closing or opening) is provided at both ends of the low potential side switch 4b.

The high-potential side switch 3a and the low-potential side switch 3b in the first inverter 3 and / or the high-potential side switch 4a and the low-potential side switch 4b in the second inverter 4 are driven by the drive signal oscillating unit 16 in the control unit 13. Driven by a signal, a desired high voltage (high potential current) is supplied to the first coil 5 and / or the second coil 6.

The control unit 13 is a drive that outputs a desired drive signal to the power calculation unit 15 that receives the detection signal from the input voltage detection unit 12 to form the power detection signal and the first inverter 3 and the second inverter 4. It includes a signal oscillating unit 16. The power calculation unit 15 confirms the detection signal from the input voltage detection unit 12 that detects the voltage across the rectifier capacitor 11 at predetermined intervals. The power calculation unit 15 detects the power input to each inverter (3, 4) based on the detection signal from the input voltage detection unit 12, and outputs the power detection information to the drive signal oscillation unit 16. Various setting information selected and set by the instruction unit 14 in the induction heating device of the first embodiment is input to the drive signal oscillation unit 16 together with the power detection information from the power calculation unit 15.

Here, the induction heating load IH and Q values corresponding to the usual induction heating of an iron pot or the like described in the present disclosure are high, and the coupling coefficient k indicating the degree of magnetic coupling between the feeding coil and the power receiving coil changes depending on the mounting position. Therefore, the non-contact power supply load PS, which requires selection of the drive cycle because the power receiving characteristics change significantly, and the low resistance induction heating load IHx, which has a low resistance and a high Q value, will be briefly described.

As shown in FIG. 1, in the induction heating device of the first embodiment, the induction heating load IH is placed on the first coil 5 to which the high frequency current from the first inverter 3 is supplied, and the second inverter. The case where the non-contact feeding load PS is placed on the second coil 6 to which the high frequency current from 4 is supplied, and the simultaneous heating / feeding driving mode is executed for each of them is shown. In the induction heating device of the first embodiment, the configuration will be described as a configuration that does not correspond to the low resistance induction heating load IHx as the load.

(A) and (b) of FIG. 2 are examples of frequency characteristic diagrams showing the relationship between the frequency [Hz] of the high-frequency current flowing through the coil and the maximum power [W]. FIG. 2A shows a frequency characteristic diagram when a load corresponding to a normal induction heating such as an iron pan is heated. On the other hand, FIG. 2B is a frequency characteristic diagram when a load having a higher Q value than the characteristic shown in FIG. 2A is driven. For example, the mounting position is displaced and the Q value is high. An example of frequency characteristics when heating a non-contact power supply load PS or a low resistance load (low resistance induction heating load IHx) such as an aluminum pan is shown. As shown in FIG. 2B, since the peak of the waveform is steep in the frequency characteristics when a load having a high Q value is driven, it is necessary to select a specific frequency in order to output the desired power. It can be understood that the output power changes significantly with a slight frequency change.

In the induction heating device of the first embodiment, when a power feeding operation is performed on the non-contact power feeding load PS, for example, a high frequency current from the first inverter 3 is supplied to the first coil 5 and a high frequency is generated from the first coil 5. A magnetic field is generated, and the power receiving coil 19 and the first coil 5 provided in the non-contact power supply load PS (non-contact device) are magnetically coupled to supply power to the load. Therefore, the mounting position of the power receiving coil 19 of the non-contact power feeding load PS is preferably a position that becomes the power feeding coil in the induction heating device, for example, completely facing the first coil 5, and the Q value increases when the position shift occurs. In addition, the coupling coefficient k becomes smaller, the feeding characteristics change significantly, and the ratio of the received power to the fed power (power receiving efficiency) deteriorates.

FIG. 3 is a frequency characteristic diagram showing the feeding characteristics when the feeding operation is performed on the non-contact feeding load PS (non-contact device) in the induction heating device of the first embodiment. In FIG. 3, the curve shown by the solid line is an example of the frequency characteristics when there is no positional deviation between the power receiving coil 19 of the non-contact device and the feeding coil of the induction heating device, and the curve shown by the broken line is the non-contact device. Is an example of frequency characteristics when the position is displaced by 15 mm. As shown in FIG. 3, when the position shift occurs, the Q value in the frequency characteristic becomes high, and in order to obtain the desired power (rated power), it is necessary to perform a sweep operation to select the frequency.

In the induction heating device of the first embodiment, even if the non-contact power feeding load PS is misaligned, a weak current lower than that during normal power feeding operation is passed through the coil so that the rated power can be supplied. The drive frequency to which the rated power can be supplied is selected by sweeping the frequency band of (Drive cycle selection operation). In the frequency characteristics shown in FIG. 3, the drive frequency f1 selected when the misalignment does not occur is higher than the drive frequency f2 selected when the misalignment occurs.

In the induction heating device of the first embodiment, the load for which heating / feeding is executed by the coils (5, 6) to which the high-frequency current from the inverters (3, 4) is supplied is the induction heating load IH or non-contact feeding. The load discrimination operation for detecting whether the load is PS is performed at the initial stage before the actual operation is started. The drive cycle selection operation described above and the load determination operation described below are simultaneously executed by performing the sweep operation.

FIG. 4 is a diagram showing a discrimination method in the load discrimination operation. In FIG. 4, the horizontal axis is the input power to the coil (5, 6), and the vertical axis is the voltage of the resonant capacitor (7, 8). The vertical axis may be the voltage or current of the coil (5, 6).

The load discrimination operation in the induction heating device of the first embodiment is a control (sweep operation in a predetermined frequency band) in which a large amount of electric power is not supplied to the coil on which the load is placed at the stage of starting the operation (the stage before the start of the actual operation). , Duty ratio control), and weak power in a preset frequency band is supplied to the coil. With respect to the change in the weak electric power, the load is discriminated based on the voltage change of the resonance capacitor (or the coil itself) of the coil. In the first embodiment, the drive cycle selection operation is performed together with the load determination operation. As shown in FIG. 4, the relationship between the input power to the coil (5, 6) and the voltage of the resonant capacitor (or the coil itself) is the region of the induction heating load IH, the region of the non-contact feeding load PS, or the region of the non-contact feeding load PS. The load is determined by which region of the low resistance induction heating load IHx region exists.

The induction heating device of the first embodiment has a configuration in which two inverters can be driven at the same time by supplying power from the same rectified power source, and can support normal induction heating by driving one of the inverters. A simultaneous drive mode is executed in which the induction heating load IH is heated and power is supplied to the non-contact power supply load PS whose power receiving characteristics greatly change depending on the mounting position by driving the other inverter.

[Simultaneous drive mode by induction heating device]
Next, in the induction heating device of the first embodiment, the induction heating load IH corresponding to the usual induction heating such as an iron pan is heated as the load of the first coil 5, and the non-contact device (non-contact device) is used as the load of the second coil 6. A simultaneous drive mode for feeding a non-contact power supply load PS) will be described. That is, the load placed facing the first coil 5 has a low Q value, and the induction capable of performing power control by changing the duty ratio at a predetermined drive frequency without selecting a drive frequency. The heating load is IH. On the other hand, when the load placed on the second coil 6 faces each other, the coupling coefficient k changes when the mounting position shifts, the power receiving characteristic changes significantly, and the Q value is high, so that the desired power is supplied. For this purpose, it is a non-contact power supply load PS that requires selection of a drive frequency.

FIG. 5 is a waveform diagram (time chart) showing the operations of the first inverter 3, the second inverter 4, the first coil 5, and the second coil 6 in the simultaneous drive mode in the induction heating device of the first embodiment.

In FIG. 5, (a) is the gate voltage waveform (drive signal) of the high potential side switch 3a of the first inverter 3, and (b) is the gate voltage waveform (drive signal) of the low potential side switch 3b of the first inverter 3. ), (C) is the gate voltage waveform (drive signal) of the high potential side switch 4a of the second inverter 4, and (d) is the gate voltage waveform (drive signal) of the low potential side switch 4b of the second inverter 4. ). FIG. 5 (e) is a waveform diagram showing a high-frequency current supplied to the first coil 5 by driving the first inverter 3. FIG. 5 (f) is a waveform diagram showing a high-frequency current supplied to the second coil 6 by driving the second inverter 4.

In the gate voltage waveforms shown in FIGS. 5A and 5B, the dead time is set so that the rising timing and the falling timing do not overlap. Similarly, in the gate voltage waveforms shown in FIGS. 5 (c) and 5 (d), the dead time is set so that the rising timing and the falling timing do not overlap.

As shown in FIG. 5, the drive frequency of the drive signal supplied to the first inverter 3 (for example, 25 kHz) is 1 / of the drive frequency of the drive signal supplied to the second inverter 4 (for example, 50 kHz). It has doubled. That is, the drive cycle Tc1 of the drive signal supplied to the first inverter 3 is twice the drive cycle Tc2 of the drive signal supplied to the second inverter 4.

As described above, in the induction heating device of the first embodiment, the high frequency current from the first inverter 3 is supplied to the first coil 5, so that a high frequency magnetic field is generated from the first coil 5, and the generated high frequency is generated. An iron pot or the like (induction heating load IH) is heated by a magnetic field. On the other hand, when the high frequency current from the second inverter 4 is supplied to the second coil 6, a high frequency magnetic field is generated from the second coil 6, and the power receiving coil 19 provided in the non-contact device which is the non-contact power supply load PS. And the second coil 6 are magnetically coupled to supply power to the load.

In the induction heating device of the first embodiment, when the induction heating load IH (iron pot or the like) is heated by the first coil 5 and the non-contact power supply load PS is supplied by the other second coil 6, the first coil is used. The drive cycle Tc1 of the first inverter 3 that supplies the high-frequency current to the fifth coil 5 is set to 1/2 times the drive cycle (Tc2) of the second inverter 4 that supplies the high-frequency current to the second coil 6. In the induction heating device of the first embodiment, a case where the induction heating load IH is heated by the first coil 5 and the non-contact power supply load PS is supplied by the second coil 6 will be described, but the load is reversed. Even in this case, the drive cycles of the first inverter 3 and the second inverter 4 can be reversed.

In the induction heating device of the present disclosure, when the induction heating load IH is heated by one coil and the non-contact power supply load PS is supplied by the other coil, the high frequency current is supplied to each coil. The drive cycle is n times (n is a natural number), 1 / n times, or a drive cycle in which current is not supplied from the rectifying capacitor to any coil at the same time at predetermined time intervals. If it is set, highly accurate feedback control can be performed for each inverter corresponding to each load. This point will be described below.

FIG. 6 is a waveform diagram showing an example of a drive signal supplied to each inverter in the single drive mode and the simultaneous drive mode in the induction heating device of the first embodiment. FIG. 6A shows the high potential side switch 3a ((A) in FIG. 6) and the low potential side when the induction heating load IH is heated by driving the first inverter 3 in the independent drive mode. It is a drive signal (drive cycle Tc3) supplied to the switch 3b ((b) of (A) in FIG. 6). (B) and (C) of FIG. 6 show drive signals supplied to the first inverter 3 and the second inverter 4 in the simultaneous drive mode.

The waveform diagram of FIG. 6B shows a case where the induction heating load IH is heated by the first coil 5 and the non-contact feeding load PS is fed by the second coil 6. In FIG. 6B, the upper side ((c), (d)) shows the drive signal of the first inverter 3 that supplies the high frequency current to the first coil 5, and the lower side ((e), (f). )) Indicates a drive signal of the second inverter 4 that supplies a high frequency current to the second coil 6.

When power is supplied to the non-contact power supply load PS whose Q value is high or the resonance point changes and it is necessary to select the drive cycle, the drive signal having the selected drive cycle Tc4a is the second inverter 4. Is supplied to. In the induction heating device of the first embodiment, the drive signal supplied to the first inverter 3 that heats the induction heating load IH drives the drive signal supplied to the second inverter 4 that supplies power to the non-contact power supply load PS. The drive cycle Tc3a (= 2 * Tc4a) is set to twice the cycle Tc4a. At this time, the drive cycle Tc3a of the drive signal supplied to the first inverter 3 is the drive cycle Tc3 (Tc3a <) of the drive signal supplied to the first inverter 3 in the independent drive mode shown in FIG. It is set shorter than Tc3). Therefore, the drive cycle of the drive signal supplied to the first inverter 3 that heats the induction heating load IH is determined by the drive cycle of the drive signal of the second inverter 4 that feeds the non-contact power supply load PS.

When power is supplied to the non-contact power supply load PS, in the induction heating device of the first embodiment, a sweep operation in which a weak current is passed through the corresponding coil in a preset frequency band at the initial stage of receiving the power supply command. To determine the load and select the drive frequency. Further, the induction heating device of the first embodiment may be configured to receive communication information from the non-contact power supply load PS and set it to a designated drive cycle included in the communication information. Further, the drive cycle for feeding the non-contact power supply load PS specified by the user in the instruction unit (operation unit) of the induction heating device may be set.

The waveform diagram of FIG. 6C shows a case where the induction heating load IH is heated by the first coil 5 and the non-contact feeding load PS is fed by the second coil 6 as in FIG. 6B. Shown. However, in the waveform diagram shown in FIG. 6 (C), the drive cycle Tc4b of the drive signal supplied to the second inverter 4 is the drive signal supplied to the second inverter 4 shown in FIG. 6 (B). The drive cycle is set to be longer than the drive cycle Tc4a of. In FIG. 6C, the upper side ((g), (h)) shows the drive signal of the first inverter 3, and the lower side ((i), (j)) shows the drive signal of the second inverter 4. Is shown. As shown in FIG. 6C, when power is supplied to the non-contact power supply load PS by the second coil 6, the drive signal of the selected drive cycle Tc4b is supplied to the second inverter 4, and the second inverter 4 is supplied with power. For the 1 inverter 3, the drive signal has a drive cycle Tc3b (= 2 * Tc4b) that is twice the drive cycle Tc4b of the drive signal supplied to the second inverter 4. At this time, the drive cycle Tc3b of the drive signal supplied to the first inverter 3 is set to be longer than the drive cycle Tc3 of the drive signal supplied to the first inverter 3 in the independent drive mode shown in FIG. 6A. (Tc3b> Tc3).

As described above, in the induction heating apparatus of the first embodiment, when each inverter (3, 4) is driven in the simultaneous drive mode with respect to the induction heating load IH and the non-contact power supply load PS, the induction heating load IH is applied. On the other hand, the drive frequency of the first inverter 3 that drives the first coil 5 to be heated is determined by the drive frequency of the second inverter 4 that drives the second coil 6 that feeds the non-contact power supply load PS. be. In the induction heating device of the first embodiment, when the induction heating load IH and the non-contact power supply load PS are driven in the simultaneous drive mode, the drive signal of the inverter for heating the induction heating load IH is used. The case where the drive cycle is twice the drive cycle of the drive signal of the inverter for supplying power to the non-contact power supply load PS has been described, but it is not specified as twice, but three times or four times. ..., n times, or 1 / n (n is a natural number), or set to a drive cycle in which there is a period in which current is not supplied from the rectifying capacitor to any coil via the inverter at regular time intervals. Just do it.

In the induction heating device of the first embodiment, by driving each inverter (3, 4) as described above in the simultaneous drive mode, the electric power supplied by each inverter is detected, and highly accurate feedback control is performed. It can be carried out.

[Power detection method for each inverter]
Next, a method of detecting the electric power supplied to each coil (5, 6) by driving the first inverter 3 and the second inverter 4 in the simultaneous drive mode will be described. FIG. 7 is a waveform diagram showing the timing of the first inverter 3, the second inverter 4, and the AD conversion for performing power detection in the simultaneous drive mode shown in FIG. 5 described above. In the waveform diagram shown in FIG. 7, the induction heating load IH is heated by driving the first inverter 3, and the non-contact feeding load PS is fed by driving the second inverter 4.

FIG. 8 is a diagram schematically showing the current flow in each operation period of the first inverter 3 and the second inverter 4. The current flow in each of the figures (a) to (d) in FIG. 8 corresponds to the operation periods A to D shown in FIG. 7. That is, during the operation period A when the high potential side switch 3a in the first inverter 3 is in the ON state and the low potential side switch 4b in the second inverter 4 is in the ON state, the current shown in FIG. 8A is It becomes a flow. The current flow shown in FIG. 8B is the operating period B when the high potential side switch 3a of the first inverter 3 is in the ON state and the high potential side switch 4a of the second inverter 4 is in the ON state. .. The current flow shown in FIG. 8C is the operating period C when the low potential side switch 3b of the first inverter 3 is in the ON state and the low potential side switch 4b of the second inverter 4 is in the ON state. .. The current flow shown in FIG. 8D is the operating period D when the low potential side switch 3b of the first inverter 3 is in the ON state and the high potential side switch 4a of the second inverter 4 is in the ON state. ..

As shown in FIG. 8, since the low potential side switches (3b, 4b) of each inverter (3, 4) are in the ON state during the operation period C, each inverter (3, 4) is turned on from the rectifier capacitor 11 (power supply side). The current path flowing to each coil (5, 6) via) is open (off), and the current flows only in the closed circuit current path by the inverter (3, 4) and the coil (5, 6). Is. That is, the operation period C is a state in which the current from the rectifier capacitor 11 on the power supply side is not supplied to the respective inverters 3 and 4, and the power storage operation in the state in which the rectifier capacitor 11 is stored in the DC power supply circuit 3. It will be a period.

In the induction heating device of the first embodiment, in the operation period C (storage operation period), the voltage across the rectifying capacitor 11 on the power supply side is detected twice with a predetermined time difference, and AD conversion is performed. (AD1, AD2). At this time, since the current only flows into the rectifying capacitor 11 from the rectifying inductor 10 (power supply side), the second detection voltage AD1 after the first first detection voltage AD1 in the operation period C (storage operation period). The detection voltage AD2 has a higher voltage across the rectifier capacitor 11.

The current flowing through the rectifying capacitor 11 is "i", the charge stored in the rectifying capacitor 11 is "Q", the capacitance of the rectifying capacitor 11 is "C", the voltage generated in the rectifying capacitor 11 is "V", and the time is "t". Then, the relationship between the following equations (1) and (2) is established.

i = dQ / dt (1)

Q = C * V (2)

Therefore, the following equation (3) is obtained from the equations (1) and (2).

i = C * dV / dt (3)

Assuming that the first detection voltage AD1 and the subsequent second detection voltage AD2 are detected in the operation period C and the time interval, which is the time difference between them, is "T", the equations (3) to the following equations (4) are obtained. Become.

i = C * (AD1-AD2) / T (4)

(AD1-AD2) in the formula (4) is a voltage difference at a predetermined time interval T in the operation period C. Therefore, since the capacitor capacity C is a value determined by design, the current value flowing into the rectifier capacitor 11 can be calculated during the operation period C. Assuming that the current change of the rectifying inductor 10 in the DC power supply circuit 2 is zero, the input power P is the product of the power supply voltage V and the input current i (P = V * i).

As described above, in the simultaneous drive mode in the induction heating device of the first embodiment, no current is supplied from the rectifying capacitor 11 on the power supply side to both the inverters (3, 4) of the first inverter 3 and the second inverter 4. If there is an operating period, the total power supplied to the first inverter 3 and the second inverter 4 can be detected. Therefore, in the above calculation, even if the drive frequencies to the first inverter 3 and the second inverter 4 have a phase difference, there is no current supply to both inverters (3, 4) at regular intervals. It can be done if it exists.

Next, the detection of each current flowing through the first inverter 3 and the second inverter 4 will be described with reference to FIG. 7. As described above, FIG. 7 shows a case where the induction heating load IH is heated by driving the first inverter 3 and the non-contact feeding load PS is fed by driving the second inverter 4. Therefore, the drive frequency of the first inverter 3 for heating the induction heating load IH is determined by the drive frequency of the second inverter 4 set for feeding the non-contact feed load PS.

In the induction heating device of the first embodiment, when the drive frequencies of the first inverter 3 and the second inverter 4 are shown in FIG. 7, the detection of the current flowing from the rectifying capacitor 11 to the second inverter 4 operates from the operation period D. This can be performed by detecting the voltage of the rectifying capacitor 11 at the timing of transition to the period A (third detection voltage AD3 shown in FIG. 7). That is, in the operating period D, the current from the rectifying capacitor 11 flows only into the second inverter 4, and the current path from the rectifying capacitor 11 to the second inverter 4 is established at the timing of transition from the operating period D to the operating period A. The road is open (off). By detecting the voltage across the rectifying capacitor 11 (third detection voltage AD3) at the timing when the current path from the rectifying capacitor 11 to the second inverter 4 becomes open, the voltage is supplied from the rectifying capacitor 11 to the second inverter 4. Power can be detected.

The voltage change of the rectifying capacitor 11 during the operation period D is determined by the difference between the current flowing from the rectifying inductor 10 and the current flowing from the rectifying capacitor 11 to the second inverter 4. Since the current from the rectifying inductor 10 is detected during the calculation of the total power supplied to the first inverter 3 and the second inverter 4 detected in the above-mentioned operation period C, the current flows from the rectifying capacitor 11 to the second inverter 4. The current and power can be calculated by calculation based on the length of the operation period D and the third detection voltage AD3. In this calculation, the voltage value of the rectifying capacitor 11 at the start of the operation period D is required, but instead, the second detection voltage AD2 after the operation period C is used to detect the second detection voltage AD2. If the time interval from the time point to the start time point of the operation period D is known, it is possible to calculate the current and electric power flowing from the rectifying capacitor 11 to the second inverter 4.

As the detection period in the operation period D, the detection operation of the second detection voltage AD2 in the operation period C described above is performed at the timing of the transition from the operation period C to the operation period D, and the second detection voltage AD2 at that time is performed. May be the period from the detection time of the third detection voltage AD3 to the detection time of the third detection voltage AD3 in the operation period D. Further, as the detection period in the operation period D, an operation of detecting the fourth detection voltage AD4 may be added in accordance with the start timing in the operation period D.

Further, in the inverter, immediately after switching, waveform ringing and noise may occur, and the voltage may not be detected accurately. Therefore, in such a case, the voltage may be detected and AD conversion may be performed by shifting the voltage back and forth by a minute period from the switching timing. In this way, even when voltage detection is performed by shifting the voltage back and forth by a minute period from the switching timing and calculation is performed based on the detection result, a difference occurs with respect to the theoretical value as the calculation result. The inventor has confirmed in actual operation experiments that there is no effect in actual use.

As described above, the electric power supplied to the second coil 6 by driving the second inverter 4 for supplying the non-contact power supply load PS is calculated to be supplied to the first inverter 3 and the second inverter 4. Since the total power is detected, it is possible to calculate the power supplied to the first inverter 3 that induces and heats the induction heating load IH. That is, the power supplied to the first inverter 3 is calculated by subtracting the power supplied to the second inverter 4 from the total power.

Since the information on the received power of the non-contact device (non-contact power supply load PS) supplied by driving one of the inverters can be detected on the non-contact device side, the information is derived from the non-contact device side. It can be transmitted to the heating device by communication. In this way, in the induction heating device that has received the information on the power received by the non-contact device, the power of induction heating by the other inverter is obtained by subtracting the power received by the non-contact device from the total output power of the induction heating device. It is also possible to detect.

[Operation of induction heating mode / non-contact power supply mode in inverter]
FIG. 9 is a flowchart showing an operation when heating the induction heating load IH by driving one of the inverters (3 or 4). In the flowchart shown in FIG. 9, this is an operation when the user selects the induction heating mode by the first coil 5 by operating a button on the instruction unit 14.
In the flowchart shown in FIG. 9, a case where the user selects the operation mode (induction heating mode / non-contact power feeding mode) of the corresponding coil (5, 6) by operating a button on the instruction unit 14 will be described. , The user does not select the operation mode of the corresponding coil on the indicating unit 14, but the user presses the "start" button on the indicating unit 14, so that the load mounted on the corresponding coil is automatically determined. The load determination operation to be performed may be executed. In this load discrimination operation, as described above, a low duty ratio weak power supplies a drive signal to the coil to supply a high-frequency current to the coil, and a resonance capacitor generated at that time is supplied. The load is determined based on the voltage of (the voltage of the corresponding coil).

When the start of the induction heating mode by the first inverter 3 is instructed (step 101), the operation mode of the second inverter 4 is confirmed in step 102.

In step 102, if the second inverter 4 is operating in the non-contact power supply mode in which power is supplied to the non-contact power supply load PS, the process proceeds to step 103.

In step 103, the drive cycle of the first inverter 3 is set to twice the drive cycle of the second inverter 4. In step 104, which is the transition from step 103, the first inverter 3 is driven in the set drive cycle, heating in the induction heating mode is started, and power supply in the non-contact power supply mode by the second inverter 4 is continued. (Simultaneous drive mode).

On the other hand, in step 102, if the second inverter 4 is not operating in the non-contact power supply mode, the process proceeds to step 105. In step 105, the drive cycle of the first inverter 3 is set to a predetermined drive cycle normally used for induction heating (for example, the drive cycle is set to 44 μs), and the process proceeds to step 104. In step 104 at this time, only the first inverter 3 is driven in the set drive cycle, and induction heating is started (independent drive mode).

Next, the operation of performing the induction heating mode / non-contact power feeding mode for the load by driving the second inverter 4 that supplies the high frequency current to the second coil 6 will be described. FIG. 10 is a flowchart showing the operation of the induction heating mode / non-contact power supply mode driven by the second inverter 4.

When the drive start is instructed to the second inverter 4 (step 201), the operation mode of the second inverter 4 is confirmed in step 202. That is, it is confirmed whether the second inverter 4 has an operation mode in which induction heating is performed on the load or an operation mode in which non-contact power supply is performed.

In step 202, if the second inverter 4 is in the non-contact power supply mode with respect to the load, the process proceeds to step 203. In step 203, if the first inverter 3 is operating in the induction heating mode, the driving of the first inverter 3 is stopped (step 204).

Next, in step 205, the drive cycle of the second inverter 4 is selected. This selection may be set to a drive cycle in which the desired output selected in the drive cycle selection operation executed at the same time as the load determination operation can be obtained, or a drive cycle predetermined for the load may be set to the indicator unit 14. The drive cycle may be set by the user or based on the communication information from the load.

In step 206, the second inverter 4 is driven by the set drive cycle, and the non-contact power supply by the second inverter 4 is started.

In step 207, the drive cycle of the first inverter 3 is set to twice the drive cycle of the second inverter 4.

In step 208, the first inverter 3 is driven in the set drive cycle, and induction heating by the first inverter 3 is started. That is, in step 208, the simultaneous drive mode in which the first inverter 3 operates in the induction heating mode and the second inverter 4 operates in the non-contact power feeding mode is started.
Note that step 206 is not limited to being performed before step 208. For example, step 205 is followed by step 207, step 207 is followed by step 208, step 208 is followed by step 206, and step 206 and step 208. The order of may be changed.

On the other hand, in step 202, if the second inverter 4 is not in the non-contact power supply mode in which the non-contact power supply is performed to the load, the process proceeds to step 211. In step 211, assuming that the second inverter 4 should operate in the induction heating mode, the drive cycle of the second inverter 4 is set to a predetermined drive cycle normally used for performing induction heating (for example, the drive cycle is 44 μs). Set to).

In step 212, the second inverter 4 is driven at the set drive cycle, and induction heating is started. That is, in step 212, in the simultaneous drive mode in which the first inverter 3 operates in the induction heating mode and the second inverter 4 operates in the induction heating mode, or in the independent drive mode in which only the second inverter 4 performs the induction heating mode. be.

Further, in step 203, if the first inverter 3 is not operating in the induction heating mode, the drive cycle of the second inverter 4 is selected (step 209). The drive cycle of the second inverter 4 in step 209 may be selected by the drive cycle selection operation in step 205 described above, and the user sets a drive cycle predetermined for the load in the indicator unit 14. Alternatively, the drive cycle may be set based on the communication information from the load.

In step 210, the non-contact power feeding mode of the second inverter 4 is started at the selected drive cycle. That is, in step 210, only the second inverter 4 is in the independent drive mode in which only the second inverter 4 operates in the non-contact power supply mode.

As described above, in the induction heating device of the first embodiment, the inverter that has been instructed to supply power is driven by the drive signal of the selected specific drive cycle to supply power to the non-contact power supply load PS. At the same time, when another inverter driven by the electric power from the same rectified power source is simultaneously instructed to heat the induction heating load, the inverter supplies power to the non-contact power supply load PS. It is set to drive with a drive cycle twice the drive cycle of the inverter for the operation. In this way, by setting the drive cycle of each inverter to be n times (n is a natural number), the current path from the power supply side (rectifier capacitor side) to the inverter is open for any inverter. The operation period (see (c) of FIG. 8: operation period C) is generated at predetermined time intervals. In this way, the induction heating is performed by detecting the voltage change of the rectifying capacitor 11 on the power supply side in the power storage state during the operation period (storage operation period) in which the current path from the power supply side is open for all the inverters. The device can detect the total power in the simultaneous drive mode of the induction heating mode and the non-contact power supply mode.

Further, an operation period in which the current path from the power supply side (rectifier capacitor side) is closed (on) only for the inverter for supplying power to the non-contact power supply load PS having a short drive cycle ((d) in FIG. 8: operation). From period D), the current path from the power supply side (rectifying capacitor side) is closed (on) only for the inverter for inductive heating to the inductive heating load IH (FIG. 8 (a): operation). By detecting the voltage change of the rectifying capacitor 11 on the power supply side at the timing of transition to period A), the power supplied from the power supply side to supply the non-contact power supply load PS in the induction heating device is detected. It becomes possible.

Further, the electric power supplied to the inverter for heating the induction heating load IH by subtracting the electric power supplied to the inverter for supplying the non-contact power supply load PS detected as described above from the total electric power. Can be detected. As a result, the induction heating device of the first embodiment can detect the power supply to each coil in the simultaneous drive mode, and can perform highly accurate feedback control for each load.

Further, if the other inverter is already operating in the induction heating mode when the power supply to the non-contact power supply load PS is started, the driving of the inverter operating in the induction heating mode is temporarily stopped, and the non-contact power supply load PS By providing the selection period of the drive cycle of the inverter for supplying power to the power supply, it is possible to shift to the simultaneous drive mode in a state where a desired output can be obtained for the non-contact power supply load PS.

As described above, the induction heating device of the first embodiment has a configuration in which a plurality of inverters are driven by power supply from the same power source, and has an induction heating mode for the induction heating load IH and non-contact with the non-contact power supply load PS. By operating the power supply mode at a desired drive cycle, highly accurate feedback control can be performed for each inverter.

(Embodiment 2)
Hereinafter, the induction heating device of the second embodiment and the drive control method thereof according to the present disclosure will be described. The induction heating device of the second embodiment has substantially the same configuration as the induction heating device of the first embodiment. The difference between the induction heating device of the second embodiment and the induction heating device of the first embodiment is that the load placed on the coil is, for example, an induction heating load IH such as an iron pan, or a non-contact electric device. A non-contact power supply load PS, or a low resistance induction heating load IHx such as an aluminum pan or a copper pan, and a drive signal corresponding to these loads is supplied to the inverter. In the description of the second embodiment, the same reference numerals are given to the elements having the same operation, configuration, and function as those of the first embodiment, and the description may be omitted in order to avoid duplicate description. ..

Also in the configuration of the induction heating device of the second embodiment, as in the configuration of the first embodiment described above, the two inverters are driven by the power supply from the same rectified power source, and each of the two coils is excited. However, the present disclosure is not limited to this configuration, and the same technical technique may be applied to a configuration in which a plurality of inverters are driven by power supply from the same power source and a plurality of coils are excited by each inverter. A similar effect can be achieved by applying the feature.

FIG. 11 is a control block diagram showing the configuration of the induction heating device according to the second embodiment. The induction heating device of the second embodiment shown in FIG. 11 has substantially the same configuration as the configuration of the first embodiment shown in FIG. 1 described above. As shown in FIG. 11, in the induction heating device of the second embodiment, the induction heating load IH is placed on the first coil 5 for induction heating, and the low resistance induction heating load is placed on the second coil 6. It is a simultaneous drive mode in which IHx is placed and heated, or a non-contact power supply load PS is placed and fed. The low resistance induction heating load IHx mounted on the second coil 6 is a low resistance induction heating cooker in which the drive frequency of the second inverter 4 is driven in a specific narrow frequency band to induce heating. (For example, an aluminum pot, a copper pot, etc.). Further, as described above, the non-contact power feeding load PS (for example, a non-contact device) has a high Q value, and the coupling coefficient k indicating the degree of magnetic coupling between the power feeding coil and the power receiving coil changes depending on the mounting position. It is a non-contact power supply that requires selection of the drive cycle of the inverter because the power receiving characteristics change significantly.

As described above, in the induction heating device of the second embodiment, the induction heating load IH is placed on the first coil 5, and the low resistance induction heating load IHx or the non-contact power supply load PS is placed on the second coil 6. In the mounted simultaneous drive mode, the drive cycle Tc1 (see FIG. 5) of the drive signal of the first inverter 3 that supplies the high frequency current to the first coil 5 is the high frequency current in the second coil 6 depending on the load. Is set to twice or three times the drive cycle Tc2 of the drive signal of the second inverter 4 that supplies the current.

In the induction heating device of the second embodiment, the user presses the "start" button, which is an instruction to start the operation mode, on the corresponding coil (5, 6) at the instruction unit 14, thereby performing the above-described embodiment. The load discrimination operation / drive cycle selection operation described in 1 is executed. In the load discrimination operation / drive cycle selection operation, the inverters (3, 4) are driven in a predetermined frequency band with a low duty ratio in order to supply weak power to the corresponding coil. The load is determined based on the voltage (coil voltage) of the resonant capacitors (7, 8) generated when the weak power is supplied to the coil. When the load is a non-contact power supply load PS or a low resistance induction heating load IHx, the drive cycle of the drive signal input to the inverter is selected. In the induction heating device of the second embodiment shown in FIG. 11, for example, a normal induction heating cooker (induction heating load IH) is placed on the first coil 5, and the induction heating device is not placed on the second coil 6. This is a simultaneous drive mode in which the contact feeding load PS or the low resistance induction heating load IHx is placed. Therefore, in the induction heating device of the second embodiment, the drive cycle of the first inverter 3 that supplies the high frequency current to the first coil 5 is the drive cycle of the second inverter 4 that supplies the high frequency current to the second coil 6. It is set to be twice or three times as large as. That is, the drive frequency of the first inverter 3 is 1/2 or 1/3 times the drive frequency of the second inverter 5.

[Operation of induction heating mode / non-contact power supply mode / low resistance induction heating mode in inverter]
Hereinafter, the operation in which the non-contact feeding mode or the low resistance induction heating mode is executed together with the induction heating mode in the induction heating device of the second embodiment will be described with reference to the flowchart.

FIG. 12 is a flowchart showing an operation when heating the induction heating load IH by driving the first inverter 3 as one of the inverters. In the flowchart shown in FIG. 12, this is an operation when the user selects the induction heating mode by the first coil 5 by operating a button on the instruction unit 14.

In step 301, when the start of the induction heating mode by one of the first inverters 3 is instructed, the operation mode of the other second inverter 4 is confirmed (steps 302 and 305).

When it is confirmed in step 302 that the second inverter 4 is operating in the non-contact power supply mode for the non-contact power supply load PS, the process proceeds to step 303.

In step 303, the drive cycle of the first inverter 3 is set to twice the drive cycle of the second inverter 4.

In step 304, which is the transition from step 303, the first inverter 3 is driven in the set drive cycle, heating in the induction heating mode is started, and power supply in the non-contact power supply mode by the second inverter 4 is continued. (Simultaneous drive mode).

On the other hand, in step 302, if the second inverter 4 is not operating in the non-contact power feeding mode, the process proceeds to step 305, and is the second inverter 4 operating in the low resistance induction heating mode with respect to the low resistance induction heating load IHx? Whether or not it is confirmed. When it is confirmed in step 305 that the second inverter 4 is operating in the low resistance induction heating mode, the process proceeds to step 306.

In step 306, the drive cycle of the first inverter 3 is set to three times the drive cycle of the second inverter 4, and the process proceeds to step 304. In step 304, which is the transition from step 306, the first inverter 3 is driven in the set drive cycle to start heating in the induction heating mode, and the heating in the low resistance induction heating mode by the second inverter 4 continues. (Simultaneous drive mode).

Further, in step 305, if the second inverter 4 is not operating in the low resistance induction heating mode, the process proceeds to step 307. In step 307, the drive cycle of the first inverter 3 is set to a predetermined drive cycle normally used for induction heating (for example, the drive cycle is set to 44 μs), and the process proceeds to step 304. In step 304 at this time, only the first inverter 3 is driven in the set drive cycle, and induction heating is started (independent drive mode).

Next, an operation of performing one of the induction heating mode, the non-contact feeding mode, and the low resistance induction heating mode with respect to the load by driving the second inverter 4 that supplies a high frequency current to the second coil 6 will be described. .. 13 and 14 show a flowchart in which one of the operation modes of the induction heating mode, the non-contact power supply mode, and the low resistance induction heating mode driven by the second inverter 4 is selected and operated.

When the drive start is instructed to the second inverter 4 (step 401), the operation mode of the second inverter 4 is confirmed in step 402. That is, it is confirmed whether the operation mode in which the second inverter 4 supplies non-contact power to the load.

In step 402, if the second inverter 4 is in the non-contact power supply mode with respect to the load, the process proceeds to step 403. In step 403, it is confirmed whether or not the first inverter 3 is operating in the non-contact power feeding mode or the low resistance induction heating mode. If the first inverter 3 is operating in the non-contact power feeding mode or the low resistance induction heating mode, the second inverter 4 is instructed to drive the non-contact power feeding mode, and at the same time, the operation mode requiring frequency control is set. Since it cannot be executed, the drive instruction to the second inverter 4 is rejected, and the user is notified to that effect (step 404).

On the other hand, if the first inverter 3 is not operating in the non-contact power feeding mode or the low resistance induction heating mode in step 403, it is confirmed in step 405 whether or not the first inverter 3 is operating in the induction heating mode. If the first inverter 3 is operating in the induction heating mode, the drive of the first inverter 3 is stopped (step 406).

Next, in step 407, the drive cycle of the second inverter 4 is selected. This selection is performed in the same manner as the selection in step 205 in the flowchart shown in FIG. 10 described above.

In step 408, the second inverter 4 is driven by the selected drive cycle, and the non-contact power supply by the second inverter 4 is started.

In step 409, the drive cycle of the first inverter 3 is set to twice the drive cycle of the second inverter 4.

In step 410, the first inverter 3 is driven in the set drive cycle, and induction heating by the first inverter 3 is started. That is, in step 410, the simultaneous drive mode in which the first inverter 3 operates in the induction heating mode and the second inverter 4 operates in the non-contact power feeding mode is started.

Further, when it is determined in step 405 that the first inverter 3 is not operating in the induction heating mode, the drive cycle of the second inverter 4 is selected in step 411, and the process proceeds to step 412.

In step 412, the non-contact power feeding mode of the second inverter 4 is started at the selected drive cycle. That is, in step 412, only the second inverter 4 is a single drive mode in which only the second inverter 4 operates in the non-contact power supply mode.

On the other hand, in step 402, if the drive instruction to the second inverter 4 is not the non-contact power feeding mode, it is confirmed in step 413 whether or not the drive instruction to the second inverter 4 is the low resistance induction heating mode.

In step 414 shown in FIG. 14, it is confirmed whether or not the first inverter 3 is operating in the non-contact power feeding mode or the low resistance induction heating mode. If the first inverter 3 is operating in the non-contact power feeding mode or the low resistance induction heating mode, the operation mode in which the second inverter 4 is instructed to drive the low resistance induction heating mode and at the same time frequency control is required. Is not possible, so the drive to the second inverter 4 is refused, and the user is notified to that effect (step 415).

On the other hand, if the first inverter 3 is not operating in the non-contact power feeding mode or the low resistance induction heating mode in step 414, it is confirmed in step 416 whether or not the first inverter 3 is operating in the induction heating mode. If the first inverter 3 is operating in the induction heating mode, the drive of the first inverter 3 is stopped (step 417).

Next, in step 418, the drive cycle of the second inverter 4 is selected. In step 419, the second inverter 4 is driven by the selected drive cycle, and low resistance induction heating by the second inverter 4 is started.

In step 420, the drive cycle of the first inverter 3 is set to three times the drive cycle of the second inverter 4.

In step 421, the first inverter 3 is driven in the set drive cycle, and induction heating by the first inverter 3 is started. That is, in step 421, the simultaneous drive mode in which the first inverter 3 operates in the induction heating mode and the second inverter 4 operates in the low resistance induction heating mode is started.

Further, when it is confirmed in step 416 that the first inverter 3 is not operating in the induction heating mode, the drive cycle of the second inverter 4 is selected in step 422, and the process proceeds to step 423.

In step 423, the low resistance induction heating mode of the second inverter 4 is started at the selected drive cycle. That is, in step 423, only the second inverter 4 is a single drive mode in which only the second inverter 4 operates in the low resistance induction heating mode.

Further, in step 413 shown in FIG. 13, if it is determined that the drive instruction to the second inverter 4 is not in the low resistance induction heating mode, the process proceeds to step 424. In step 424, the drive cycle of the second inverter 4 is set to a predetermined drive cycle normally used for induction heating (for example, the drive cycle is set to 44 μs), and the process proceeds to step 425. In step 425, the second inverter 4 is driven at the set drive cycle, and induction heating is started.

In the induction heating device of the second embodiment, the load placed facing the second coil 6 has a high Q value, and it is necessary to select the drive frequency of the second inverter 4, and a specific drive cycle is required. It is a specific load (for example, non-contact feeding load PS, low resistance induction heating load IHx, etc.) that needs to supply the high frequency current of the above. When the drive frequency of the second inverter 4 is controlled in the adjustment of the output power for such a specific load, the drive frequency of the first inverter 3 is controlled in conjunction with the control. In the first inverter 3, the induction heating load IH placed facing the first coil 5 has a low Q value, and it is possible to perform power control by changing the duty ratio at a set drive frequency. Is.

As described above, in the induction heating device of the second embodiment, it is necessary to select the drive frequency of the inverter, and it is necessary to supply a high frequency current of a specific drive cycle (for example, a non-contact power supply load PS, Or, when a low resistance induction heating load (IHx, etc.) is mounted on one coil, an appropriate drive cycle is selected and driven according to the specific load mounted, and at the same time, it is induced on the other coil. When a heating load is placed, a high-frequency current is supplied to the other coil at a drive cycle corresponding to the drive cycle selected for one coil.

Therefore, in the simultaneous drive mode as described above, the operating period (see (c): operating period C in FIG. 8) in which the current path from the power supply side (rectifying capacitor side) is open is set for any of the inverters. The drive cycle is set so as to occur at predetermined time intervals. In this way, by forming a drive signal having an operating period in which the current path from the power supply side is open at the same time for all the inverters and detecting the voltage change of the rectifier capacitor 11 on the power supply side, the induction heating device is used. It is possible to detect the total power in the simultaneous drive mode. Since the detection of the total power has been described in the above-described first embodiment, it will be omitted here.

Further, an operating period in which the current path from the power supply side (rectifying capacitor side) is open only for one inverter for the above specific load (PS, IHx, etc.) (FIG. 8 (d): operating period). From (see D), the operating period in which the current path from the power supply side (rectifying capacitor side) is open only for the other inverter for inductive heating to the induced heating load IH ((a) in FIG. 8: operating period). By detecting the voltage change of the rectifier capacitor 11 on the power supply side at the timing of transition to (see A), the power supplied from the power supply side to one coil on which a specific load (PS, IHx, etc.) is placed. Can be detected.

Therefore, in the induction heating device of the second embodiment, it is possible to detect the power supply to each coil in the simultaneous drive mode, and it is possible to perform highly accurate feedback control for each load.

As described above, the induction heating device of the second embodiment has a configuration in which a plurality of inverters are driven by power supply from the same power source, and has an induction heating mode for an induction heating load IH and a specific load (PS, IHx, etc.). By operating the operation mode for each inverter at a desired drive cycle, highly accurate feedback control can be performed for each inverter.

(Embodiment 3)
Hereinafter, the induction heating device of the third embodiment according to the present disclosure will be described. The induction heating device of the third embodiment has substantially the same configuration as the induction heating device of the first embodiment. The difference between the induction heating device of the third embodiment and the induction heating device of the first embodiment is the case where the specific load mounted on the coil operates at a specific drive frequency. For example, the load placed on one coil is, for example, an induction heating load IH of an iron pan or the like, and the other load operates at a specific drive frequency, for example, a drive frequency of around 36 kHz. This is the case where the non-contact power supply load PS is used. In the description of the third embodiment, the same reference numerals are given to the elements having the same operation, configuration, and function as those of the first embodiment, and the description may be omitted in order to avoid duplicate description. ..

In the configuration of the induction heating device of the third embodiment, for example, the induction heating load IH is placed on one first coil 5 and as a specific load on the other second coil 6, for example, a drive frequency of around 36 kHz. The case where the non-contact power supply load PS operating in the above mode is mounted and the simultaneous drive mode is executed will be described.

As described in the first and second embodiments described above, in the simultaneous drive mode, when the drive frequency of the specific load is set to around 36 kHz, in order to supply a high frequency current to the first coil 5. A drive frequency of around 18 kHz, which is a double drive cycle, is set in the first inverter 3. However, since the audible frequency that humans can generally hear is in the range of about 20 Hz to 20 kHz, if a drive frequency of about 18 kHz is set, it will be heard as an unpleasant sound for humans.

Therefore, in the configuration of the induction heating device of the third embodiment, the drive frequency of the inverters (3, 4) is set to be a region excluding the audible frequency band. For example, in the simultaneous drive mode, when the drive frequency of the specific load mounted on the second coil 6 is set to 36 kHz and the induction heating load IH is mounted on the first coil 5, the first The drive frequency of 24 kHz, which is two-thirds times the drive frequency, is set for the first inverter 3 that supplies the high-frequency current to the coil 5. The drive cycle is 3/4 times. As a result, the first inverter 3 is set to a drive frequency in a frequency band outside the audible frequency band exceeding 20 kHz, and the user does not hear an unpleasant sound.

Also in the induction heating device of the third embodiment, as in the second embodiment described above, a specific load (for example, non-contact feeding load PS, low resistance induction heating load IHx, etc.) for which it is necessary to select the drive frequency of the inverter, etc. ) Is mounted on one coil, an appropriate drive cycle is selected and driven according to the loaded load, and at the same time, when an induction heating load is mounted on the other coil. , The drive frequency corresponding to the drive frequency selected for one inverter is set for the other inverter. However, the drive frequency set at this time is set to be a region excluding the audible frequency band.

Further, also in the induction heating device of the third embodiment, as in the configuration of the first and second embodiments described above, in the simultaneous drive mode, the drive frequencies of the respective inverters are set, so that all of them are formed. In the inverter of the above, a drive signal is formed in which an operation period in which the current path from the power supply side is simultaneously opened is generated at predetermined time intervals. Therefore, the total power in the simultaneous drive mode by the induction heating device of the third embodiment is detected by detecting the voltage change of the rectifying capacitor 11 on the power supply side during the operation period in which the current path from the power supply side is simultaneously opened. It becomes possible.

Further, also in the induction heating device of the third embodiment, by detecting the voltage change of the rectifying capacitor 11 at the timing described in the above-described first and second embodiments, the power supply side with respect to one coil The power supplied is detected, and the power supplied from the power supply side to the other coil is calculated.

Therefore, in the induction heating device of the third embodiment, it is possible to detect the power supply to each coil in the simultaneous drive mode, and it is possible to perform highly accurate feedback control for each load.

As described above, the induction heating device of the third embodiment has a configuration in which a plurality of inverters are driven by power supply from the same power source, and has an induction heating mode for an induction heating load IH and a specific load (PS, IHx, etc.). By operating the operation mode for each inverter at a desired drive cycle, highly accurate feedback control can be performed for each inverter.

In the induction heating device of the third embodiment, as a specific example, a specific load operating at a drive frequency of around 36 kHz is placed, and the drive frequency for the induction heating load IH becomes the drive frequency for the specific load. On the other hand, for example, the setting of the drive frequency of 2/3 times has been described, but the value of 2/3 times the drive frequency in the third embodiment does not limit the configuration of the induction heating device of the present disclosure. At least, if the drive frequency is set so that power is not supplied to any of the inverters from the power supply side at the same time at predetermined intervals, the total power in the simultaneous drive mode can be detected. Also, only for the inverter for a specific load, if there is an operating period in which the current path from the power supply side (rectifier capacitor side) is closed (on), it is possible to detect the power for the specific load. It becomes.

In the description of the above embodiment, the drive frequency of the inverter for heating the induction heating load IH has been described as being one value (for example, 23 kHz), but it is not specified as one value. .. For example, there is an induced heating load IH that is induced to be heated by a binary drive frequency, such as a pot that is induced to be heated based on a drive frequency of 23 kHz and a pot that is induced to be heated on a basis of 30 kHz. Therefore, for example, when power is supplied to the non-contact power supply load PS by one coil at a drive frequency of 46 kHz, when the induction heating load IH is simultaneously heated by the other coil, the induction heating load IH If is a pot that is induced and heated on a 23 kHz basis, the drive cycle is set to a ratio of 1: 2. On the other hand, if the induction heating load IH mounted on the other coil is an induction heating pot based on 30 kHz, the drive cycle is set to a ratio of 2: 3, for example, the drive frequency is 45 kHz. The drive signal of each inverter is set to a drive frequency of 30 kHz. In this way, in the simultaneous drive mode, the drive signal is set so that an operation period (storage operation period) in which power is not supplied from the power supply side to any of the inverters occurs at the same time at predetermined intervals, and the accuracy is set for each inverter. It is possible to perform high feedback control.

Further, in the present disclosure, the selection timing of the drive cycle for the electric device that needs to select the drive cycle of the inverter is not only at the initial stage of driving when the drive cycle selection operation described in the above embodiment is executed, but also during the simultaneous drive mode. It may be changed at any time. In that case, the drive cycle of the inverter that induces and heats the induction heating load IH is the drive cycle of the inverter for the electric device that needs to be selected so that the ratio of the drive cycle set at the initial stage of the simultaneous drive mode is maintained. By changing at the same time as the change, highly accurate feedback control can be maintained.

In the present disclosure, as specifically described in each of the above-described embodiments, in an induction heating device that drives a plurality of inverters by supplying power from the same rectified power source, for each device having a different drive frequency. Therefore, it is possible to efficiently operate the device in a desired state even for a device having a particularly large Q value. Therefore, by using the induction heating device and the drive control method thereof of the present disclosure, it is possible to perform feedback control for each inverter and perform highly accurate drive control for the inverter.

The present disclosure provides an induction heating device having excellent commercial value, high reliability and safety, and for example, provides an induction heating device capable of efficiently performing non-contact power feeding together with induction heating. can do.

1 AC power supply 2 DC power supply circuit 3 1st coil 3a High potential side switch 3b Low potential side switch 4 2nd inverter 4a High potential side switch 4b Low potential side switch 5 1st coil 6 2nd coil 7 1st resonance capacitor 8th 2 Resonant capacitor 9 Diode bridge 10 Rectifying inductor 11 Rectifying capacitor 12 Input voltage detector 13 Control unit 14 Indicator 15 Power calculation unit 16 Drive signal oscillation unit 19 Power receiving coil IH Inductive heating load PS Non-contact power supply load IHx Low resistance Inductive heating load

Claims (24)

A DC power supply circuit that outputs a DC voltage,
A plurality of inverters to which power is supplied from the DC power supply circuit, and
A plurality of coils formed by driving the plurality of inverters to which high-frequency currents are supplied, and
A control unit that detects a change in an electric signal in the DC power supply circuit due to the drive of the plurality of inverters, detects power supplied to the plurality of inverters, and controls a drive signal for driving the plurality of inverters. With
The control unit
The drive signal for driving one of the plurality of inverters is controlled so that the drive cycle is linked according to the drive signal for driving the other inverter.
The current paths from the DC power supply circuit to the plurality of inverters are simultaneously opened to form a drive signal in which the storage operation period in which the DC power supply circuit is in the storage state has a predetermined time interval.
An induction heating device configured to detect the total power supplied to the plurality of inverters based on a change in an electric signal of the DC power supply circuit during the storage operation period. The control unit calculates the power supplied to each of the inverters of the plurality of inverters based on the change of the electric signal of the DC power supply circuit in the operation period other than the storage operation period in the drive signals for driving the plurality of inverters. The induction heating device according to claim 1, which is configured to be calculated from the total electric power. The plurality of inverters include a first inverter and a second inverter, high-frequency current from the first inverter is supplied to the first coil of the plurality of coils, and high-frequency current from the second inverter is the first of the plurality of coils. It has a configuration that is supplied to two coils, and has a configuration.
In the simultaneous drive of the first inverter and the second inverter, the control unit sets the drive cycle of the first inverter to n times or 1 / n times the drive cycle of the second inverter (n is a natural number). The induction heating device according to claim 1 or 2, which is configured as described above. The DC power supply circuit comprises a low-pass filter having an inductor and a capacitor.
The first inverter and the second inverter are connected in parallel to the output side of the low-pass filter.
The control unit
In the storage operation period in which the period in which the current path from the capacitor to the first inverter is open and the period in which the current path from the capacitor to the second inverter is open overlap, the voltage across the capacitor is staggered. 3. The total power supplied from the DC power supply circuit to the first inverter and the second inverter is calculated based on the results of the two detections. The induction heating device according to the description. In a state where a load that does not require selection of a drive frequency is driven by the first inverter and a load that requires selection of a drive frequency is driven by the second inverter.
The control unit
4. The fourth aspect of the present invention is configured to detect the voltage across the capacitor and calculate the electric power supplied to the second inverter at the timing when the current path from the capacitor to the second inverter changes from the closed path to the open path. The induction heating device according to. The control unit
The fifth aspect of claim 5, wherein the electric power supplied to the first inverter is calculated based on the calculation result of the electric power supplied to the second inverter and the total electric power supplied to the plurality of inverters. Induction heating device. A DC power supply circuit that outputs a DC voltage,
A plurality of inverters to which power is supplied from the DC power supply circuit, and
A plurality of coils formed by driving the plurality of inverters to which high-frequency currents are supplied, and
A control unit that detects a change in an electric signal in the DC power supply circuit due to the drive of the plurality of inverters, detects power supplied to the plurality of inverters, and controls a drive signal for driving the plurality of inverters. It is a drive control method of an induction heating device equipped with
The drive signal that drives one inverter in the plurality of inverters interlocks the drive cycle according to the drive signal that drives the other inverter.
The current paths from the DC power supply circuit to the plurality of inverters are simultaneously opened to form a drive signal in which the storage operation period in which the DC power supply circuit is in the power storage state has a predetermined time interval, and the power storage is performed. A drive control method for an induction heating device, comprising a step of detecting the total power supplied to the plurality of inverters based on a change in an electric signal of the DC power supply circuit during an operation period. The power supplied to each of the inverters of the plurality of inverters is calculated from the total power based on the change of the electric signal of the DC power supply circuit in the operation period other than the storage operation period in the drive signals for driving the plurality of inverters. The drive control method for an induction heating device according to claim 7, further comprising a step. The plurality of inverters include a first inverter and a second inverter, high-frequency current from the first inverter is supplied to the first coil of the plurality of coils, and high-frequency current from the second inverter is the first of the plurality of coils. It is a drive control method of an induction heating device having a configuration of being supplied to two coils.
In the simultaneous drive of the first inverter and the second inverter, the drive cycle of the first inverter is set to n times or 1 / n times (n is a natural number) of the drive cycle of the second inverter, including a step. The drive control method for an induction heating device according to claim 7 or 8. A drive control method for an induction heating device in which the DC power supply circuit includes a low-pass filter having an inductor and a capacitor, and the first inverter and the second inverter are connected in parallel on the output side of the low-pass filter.
In the storage operation period in which the period in which the current path from the capacitor to the first inverter is open and the period in which the current path from the capacitor to the second inverter is open overlap, the voltage across the capacitor is staggered. 9. The total power supplied from the DC power supply circuit to the first inverter and the second inverter is calculated based on the results of the two detections. The drive control method of the induction heating device according to the above. In a state where a load that does not require selection of a drive frequency is driven by the first inverter and a load that requires selection of a drive frequency is driven by the second inverter.
10. The claim 10 includes a step of detecting the voltage across the capacitor and calculating the power supplied to the second inverter at the timing when the current path from the capacitor to the second inverter changes from the closed path to the open path. The drive control method of the induction heating device according to the above. The eleventh claim includes a step of calculating the electric power supplied to the first inverter based on the calculation result of the electric power supplied to the second inverter and the total electric power supplied to the plurality of inverters. Drive control method of the induction heating device. A DC power supply circuit that outputs a DC voltage,
A first inverter to which power is supplied from the DC power supply circuit to form a first high-frequency current, and
A second inverter to which power is supplied from the DC power supply circuit to form a second high-frequency current, and
A first coil that generates a first high-frequency magnetic field by supplying a first high-frequency current from the first inverter, and
A second coil that generates a second high-frequency magnetic field by supplying a second high-frequency current from the second inverter, and
A drive control method for an induction heating device including a control unit that outputs a drive signal for driving and controlling the first inverter and the second inverter.
Detecting an electric signal that changes in the DC power supply circuit by driving the first inverter and the second inverter,
When the first inverter and the second inverter are simultaneously driven and controlled by the control unit, the drive cycle of the first inverter becomes n times or 1 / n times (n is a natural number) the drive cycle of the second inverter. Set,
It is supplied to the first inverter based on the change of the electric signal detected in a specific period of the drive signal in which the current path from the DC power supply circuit to the first inverter and the second inverter is simultaneously opened. A drive control method for an induction heating device having a step, which calculates a total value of electric power and electric power supplied to the second inverter. 13. The thirteenth aspect of the present invention, wherein the drive cycle of the first inverter when the first inverter is driven independently and the drive cycle of the first inverter when the first inverter and the second inverter are driven at the same time are different. Drive control method of the induction heating device. When the driving of the second inverter is started while the first inverter is being driven independently, the driving cycle of the first inverter is driven independently based on the driving cycle of the second inverter. The drive control method for an induction heating device according to claim 13 or 14, wherein the drive cycle is changed from the drive cycle at the time of the operation. The induction heating according to any one of claims 13 to 15, wherein the driving of the first inverter is temporarily stopped when the driving of the second inverter is started while the first inverter is being driven independently. Device drive control method. When the second inverter is started to be driven while the first inverter is operating independently in the induction heating mode, a drive cycle selection operation for sweeping the second inverter with a drive signal having a current lower than usual is executed. Then, when selecting the drive cycle of the second inverter,
The drive control method for an induction heating device according to claim 16, wherein the drive of the first inverter is temporarily stopped. The drive control method for an induction heating device according to claim 17, wherein when the drive cycle of the second inverter is selected and the drive of the second inverter is started, the drive of the first inverter is restarted. When the driving of the second inverter is stopped while the first inverter and the second inverter are operating at the same time, the driving cycle of the first inverter is changed to the driving cycle when the first inverter is driven independently. The drive control method for an induction heating device according to any one of claims 13 to 18. 13. Drive control method of the induction heating device. Further including a step of selecting whether to operate the second inverter in the non-contact power feeding mode or the induction heating mode.
When the non-contact power supply mode is selected, the drive cycle of the first inverter when the first inverter is driven independently and the first inverter when the first inverter and the second inverter are driven at the same time. The drive control method for an induction heating device according to any one of claims 13 to 20, wherein the drive cycle of the induction heating device is different. A drive control method for an induction heating device in which the DC power supply circuit includes a low-pass filter composed of an inductor and a capacitor, and the first inverter and the second inverter are connected in parallel on the output side of the low-pass filter. ,
The voltage applied to the capacitor is detected and
In the storage operation period in which the period in which the current path from the capacitor to the first inverter is open and the period in which the current path from the capacitor to the second inverter is open overlap, the voltage across the capacitor is staggered. The total power supplied from the DC power supply circuit to the first inverter and the second inverter is calculated based on the results of the two detections. 21. The drive control method for an induction heating device according to any one of items. In a state where a load that does not require selection of a drive frequency is driven by the first inverter and a load that requires selection of a drive frequency is driven by the second inverter.
The voltage across the capacitor is detected at the timing when the current path from the capacitor to the first inverter changes from the open path to the closed path and when the current path from the capacitor to the second inverter changes from the closed path to the open path. The drive control method for the induction heating device according to claim 22, further comprising a step of calculating the electric power supplied to the second inverter. Including a step of calculating the power supplied to the first inverter based on the calculation result of the power supplied to the second inverter and the total power supplied to the first inverter and the second inverter. The drive control method for an induction heating device according to claim 23.

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