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Electromagnetic induction heating device

A technology of electromagnetic induction heating and heating coil, applied in induction heating, induction heating control and other directions, can solve the problem of inverter interference sound, etc., and achieve the effect of preventing interference sound, reducing the number of parts, and suppressing withstand voltage

Active Publication Date: 2013-05-01
HITACHI APPLIANCES INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In addition, in a device with a plurality of heating coils, in the case of heating different objects to be heated separately, when controlling the drive frequency of the inverter to perform power control, there may also be problems caused by the frequency difference between the inverters. The problem of interfering sounds

Method used

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Examples

Experimental program
Comparison scheme
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Embodiment 1)

[0044] figure 1 It is a circuit configuration diagram of the electromagnetic induction heating device of Embodiment 1, and an unshown object to be heated (for example, a cooking pot) is magnetically coupled to a heating coil to supply power to the object to be heated (cooking pot). exist figure 1 Among them, between the positive electrode and the negative electrode of the DC power supply 1, a power semiconductor switching element 3a, an inductor 41, and a switching element 3b are connected in series. In addition, a resonant load circuit 60 , a smoothing capacitor 44 , and a diode 43 are connected in series at both ends of the inductor 41 . The resonant load circuit 60 is constituted by the heating coil 11 and the resonant capacitor 13 connected in parallel. Diodes 4a, 4b are connected in antiparallel to switching elements 3a, 3b, respectively.

[0045] exist figure 1 Among them, the switching elements 3a, 3b, the inductor 41, and the diode 43 constitute the chopper circuit...

Embodiment 2)

[0054] image 3 It is a circuit configuration diagram of the electromagnetic induction heating device of Example 2. For and Example 1 figure 1 , figure 2 The same parts are attached with the same symbols, and explanations are omitted.

[0055] exist image 3 in, with figure 1 The difference is that the switching element 3c is connected between the resonant capacitor 13 and the switching element 3b, the diode 4c is connected in antiparallel to the switching element 3c, and the snubber capacitor 14 is connected in parallel with the switching element 3b. In addition, the capacity of the snubber capacitor 14 is smaller than that of the resonant capacitor 13 .

[0056] Next, the operation of this embodiment will be described. Figure 4 The operation waveforms of each part of this embodiment are shown. Figure 4 (a) shows the operation waveform at low power output, Figure 4 (b) shows the operation waveform at the time of high power output. exist Figure 4 in, toward fi...

Embodiment 1

[0062] Compared with the first embodiment, the present embodiment can suppress the withstand voltage of the switching element 3b because the voltage applied to the switching element 3b is clamped. Figure 5 represents the relationship between the on-time duty ratio of the switching element 3a and the filter voltage, Image 6 Indicates the relationship between filtered voltage and input power. filter voltage, such as Figure 5 As shown, increasing in proportion to the on-time duty cycle of switching element 3a, the input power as Image 6 , increases proportionally to the square of the filtered voltage.

[0063] in addition, Figure 7 Indicates the relationship between the input power and the voltage applied to the switching element 3b, Figure 8 Indicates the relationship between input power and resonance capacitor voltage. The solid line represents the characteristics of this embodiment, and the dotted line represents the characteristics when the chopper circuit 10 is ex...

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Abstract

The present invention aims to provide an electromagnetic induction heating device which can restrain magnetic field variation in a heating coil and prevents buzz sound from a heated object. The electromagnetic induction heating device is provided with the following components: a chopper circuit which performing boosting or chopping on DC voltage from a DC power supply; and an inverter which converts the DC voltage from the chopper circuit to AC voltage. The chopper circuit is provided with a first switch component, an inductor and a second switch component which are connected in series between an anode and a cathode of the DC power supply. The voltage resonance type inverter is provided with the heating coil and a second switch component which are connected in series, and a resonance capacitor that is equipped parallelly with the heating coil. A wave filtering circuit is equipped parallelly with the series circuit which is composed of the heating coil and the second switch component, thereby filtering the DC voltage output from the chopper circuit. The second switch component which is commonly used in the chopper circuit and inverter is used as a boosting switch component of the chopper circuit.

Description

technical field [0001] The present invention relates to an electromagnetic induction heating device of an inverter type such as an induction heating cooker. Background technique [0002] In the electromagnetic induction heating device, a high-frequency current flows through a heating coil to generate eddy current in a metal object to be heated arranged close to the coil, and heat is generated by the resistance of the object itself. Because it can control the temperature of the object to be heated and has high safety, it is recognized as a new heat source. [0003] As a conventional example of an electromagnetic induction heating device, there is an induction heating device disclosed in Japanese Patent No. 4186946 . The device consists of a rectifier circuit for converting AC power to DC, a heating coil, and an inverter circuit. The inverter circuit has a switching element connected in series with the heating coil and a resonant capacitor connected in parallel with the heati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B6/06
Inventor 庄司浩幸宇留野纯平矶贝雅之
Owner HITACHI APPLIANCES INC