Power control apparatus for high frequency dielectric heating and control method employed by the power control apparatus

A technology of power control unit and high-frequency medium, which is applied in microwave heating, electric/magnetic/electromagnetic heating, household cooking utensils, etc., and can solve problems such as input current waveform distortion

Active Publication Date: 2014-12-10
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned switching still involves the problem that, in combination with the fact that the magnetron is a non-linear load as indicated by the VAK (anode-cathode voltage)-Ib characteristic in Fig. 63, the current waveform of the commercial power supply to the magnetron drive power supply becomes a waveform containing a large number of harmonic components
Therefore, if the magnetron temperature matches the low temperature, when the magnetron temperature becomes higher, the input current waveform is distorted

Method used

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  • Power control apparatus for high frequency dielectric heating and control method employed by the power control apparatus
  • Power control apparatus for high frequency dielectric heating and control method employed by the power control apparatus
  • Power control apparatus for high frequency dielectric heating and control method employed by the power control apparatus

Examples

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Effect test

Embodiment 1

[0203] figure 1 is a block diagram illustrating a high-frequency heating device according to Embodiment 1 of the present invention. exist figure 1 In the example, the high-frequency heating device includes an inverter 40 , a controller 45 for controlling the first and second semiconductor switching elements 3 and 4 of the inverter, and a magnetron 12 . The inverter 40 includes an AC power source 50 , a diode bridge rectifier 60 , a smoothing circuit 61 , a resonance circuit 36 ​​, first and second semiconductor switching elements 3 and 4 , and a voltage doubler rectifier 11 .

[0204] In a diode bridge rectifier 60 composed of four diodes 63 , the AC voltage of the AC power source 50 is rectified and converted into a DC power source 51 via a smoothing circuit 61 composed of an inductor 64 and a third capacitor 7 . Then, it is converted into high-frequency alternating current through the resonance circuit 36 ​​composed of the first capacitor 5, the second capacitor 6, and t...

Embodiment 2

[0239] Embodiment 2 of the present invention will be discussed below. Embodiment 2 of the present invention relates to the structure of the controller, and has figure 1 structure in which the input current waveform information 90 and the power control information 91 from the comparator 74 are mixed, filtered, and converted into on and off driving signals of the semiconductor switching elements 3, 4 of the inverter for use . Therefore, it is unnecessary to process the waveform information of the commercial power supply voltage conforming to the nonlinear load characteristic of the magnetron, simplifying the frequency modulation signal generator, and relative to Figure 64 In the example of the prior art, the commercial power supply voltage waveform information also becomes unnecessary, thereby contributing to the practical miniaturization of the machine structure, simplifying the control program, and shortening the processing time, and thus the machine performance can be impr...

Embodiment 3

[0242] Embodiment 3 of the present invention relates to an input current detection section. figure 1 , the input current detection section detects the input current of the inverter using the CT 71 and the like, and performs rectified output from the rectifier 72 . According to this structure, the input current is detected using CT or the like, and thus a large signal can be obtained while maintaining the isolation property, so that the effect of input current waveform shaping is large, and the quality of the input current is improved.

[0243] exist figure 2 In the example shown, after rectification in the rectifier 61 of the inverter, the input current detection section detects a unidirectional current via a shunt resistor 86 located between the rectifier 60 and the smoothing circuit 61, amplified by an amplifier (amplifier) ​​85 across the shunt voltage across the resistor 86 and outputs that voltage. This configuration has the advantage of configuring the input current ...

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PUM

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Abstract

Provided is a power control apparatus for high frequency dielectric heating, which is not affected by magnetron types, fluctuations of characteristics, power supply voltages and the like. The power control apparatus is provided with input current detecting sections (71, 72) for detecting an input current to an inverter circuit (10), which rectifies (31) an alternating current power supply voltage (20) and converts it into high-frequency power by performing high-frequency switching. A switching frequency control signal (92) wherein input current waveform information (90) from the input current detecting section and power control information (91) are mixed, is converted into a drive signal of semiconductor switching elements (3, 4) of the inverter circuit.

Description

technical field [0001] The present invention relates to power control of high-frequency dielectric heating using magnetrons, particularly high-frequency dielectric heating that is not affected by differences in characteristics of magnetrons, magnetron types, or differences in anode temperature of the magnetrons. Background technique [0002] Heretofore, power supplies installed in high-frequency heating equipment have become large and heavy, and therefore, there have been demands for miniaturization and weight reduction of the power supplies. Therefore, in various fields at present, miniaturization, weight reduction, and cost reduction by switching the power supply are being actively pursued. In a high-frequency heating apparatus for cooking food by microwaves generated in a magnetron, miniaturization and weight reduction of a power supply for driving the magnetron are required, and this is accomplished by a switchable inverter. [0003] Specifically, the high-frequency inv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B6/68H05B6/66
CPCH05B6/685Y02B40/143Y02B40/00
Inventor 末永治雄安井健治酒井伸一城川信夫守屋英明木下学
Owner PANASONIC CORP
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