JP4120536B2

JP4120536B2 - Induction heating cooker

Info

Publication number: JP4120536B2
Application number: JP2003309796A
Authority: JP
Inventors: 信二近藤; 嘉朗石尾; 知也藤濤
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2003-09-02
Filing date: 2003-09-02
Publication date: 2008-07-16
Anticipated expiration: 2023-09-02
Also published as: JP2005078993A

Description

本発明は、主として一般家庭で使用される誘導加熱調理器に関するものである。 The present invention relates to an induction heating cooker mainly used in general households.

従来この種の誘導加熱調理器としては、図８に示すように、トッププレート２５に置かれた調理鍋２４を加熱コイル２３から発生する高周波磁界により誘導加熱する誘導加熱調理器において、サーミスタ等の接触式温度検知素子で構成される感熱素子２６と、調理鍋２４の放射エネルギーを検知する赤外線センサー２７とを有する構成で、感熱素子２６で絶対温度を検知し、赤外線センサー２７で温度変化を検知することにより、調理鍋２４の急激な温度変化に素早く反応する加熱制御を行うものであった（例えば、特許文献１参照）。
特許第２８９７３０６号公報 Conventionally, as this type of induction heating cooker, as shown in FIG. 8, an induction heating cooker that induction-heats a cooking pot 24 placed on a top plate 25 by a high-frequency magnetic field generated from a heating coil 23, such as a thermistor, etc. It has a configuration including a thermal element 26 composed of a contact-type temperature detection element and an infrared sensor 27 that detects the radiant energy of the cooking pot 24. The thermal element 26 detects an absolute temperature and the infrared sensor 27 detects a temperature change. By doing, the heating control which reacts quickly with the rapid temperature change of the cooking pot 24 was performed (for example, refer patent document 1).
Japanese Patent No. 2897306

しかし上記従来の誘導加熱調理器では、調理鍋２４の底面が反ってトッププレート２５から浮いていると感熱素子２６に被加熱物２の温度が正しく伝わらないため、正確に温度を制御することが困難であるという課題があった。また、あらかじめ温度が上がっている調理鍋２４をセットされた直後は、感熱素子２６に調理鍋２４の温度が伝わるまでかなりの時間要するため、その間は正確に温度を制御することが困難であるという課題もあった。 However, in the above-described conventional induction heating cooker, if the bottom surface of the cooking pot 24 is warped and floats from the top plate 25, the temperature of the object to be heated 2 is not correctly transmitted to the thermal element 26, so that the temperature can be accurately controlled. There was a problem that it was difficult. Further, immediately after the cooking pot 24 whose temperature has been raised in advance is set, it takes a considerable time until the temperature of the cooking pot 24 is transmitted to the thermal element 26, and during that time, it is difficult to accurately control the temperature. There were also challenges.

前記従来の課題を解決するために、本発明の誘導加熱調理器は、高周波磁界を発生し被加熱物を加熱する誘導加熱コイルと、前記誘導加熱コイルに高周波電流を供給するインバータ回路と、前記被加熱物の材質を判定してアルミ領域・ステンレス領域・鉄領域を検出する材質判定手段と、前記被加熱物の放射エネルギー量で前記被加熱物の温度を検知する温度検知手段と、前記材質判定手段により検出した前記被加熱物の材質に応じて前記温度検知手段の検出値を補正する温度補正手段と、前記温度補正手段による補正温度に応じて前記インバータ回路の出力の大きさを制御する出力制御手段とを備え、前記温度補正手段は、前記ステンレス領域の場合の前記温度検知手段の検出値と前記被加熱物の温度との相関を基準値として前記ステンレス領域の場合の補正温度とし、前記アルミ領域の場合は前記基準値に第１の所定値を減算して補正温度とし、前記鉄領域の場合は前記基準値に第２の所定値を加算して補正温度として補正するものである。 In order to solve the above conventional problems, the induction heating cooker of the present invention, an induction heating coil for heating the generating a high-frequency magnetic field object to be heated, an inverter circuit for supplying a high-frequency current to the induction heating coil, wherein Material determining means for detecting the material of the object to be heated to detect an aluminum region, a stainless steel region, and an iron region, temperature detecting means for detecting the temperature of the object to be heated by the amount of radiant energy of the object to be heated, and the material Temperature correction means for correcting the detection value of the temperature detection means according to the material of the object to be heated detected by the determination means, and control of the output of the inverter circuit according to the correction temperature by the temperature correction means and an output control means, said temperature correction means, the correlation between the temperature detection value and the object to be heated of the temperature sensing means in the case of the stainless steel region as a reference value stainless In the case of the aluminum region, a first predetermined value is subtracted from the reference value to obtain a correction temperature. In the case of the iron region, a second predetermined value is added to the reference value. The correction temperature is corrected .

以上のように請求項１〜２に記載の発明によれば、被加熱物の材質の影響無く高精度に被加熱物の温度を所定温度に維持することができる。 As described above, according to the first and second aspects of the present invention, the temperature of the object to be heated can be maintained at a predetermined temperature with high accuracy without being affected by the material of the object to be heated.

また、即応性の良い温度制御を実現することができる。 Moreover, temperature control with good responsiveness can be realized.

請求項１に記載の発明は、高周波磁界を発生し被加熱物を加熱する誘導加熱コイルと、前記誘導加熱コイルに高周波電流を供給するインバータ回路と、前記被加熱物の材質を判定してアルミ領域・ステンレス領域・鉄領域を検出する材質判定手段と、前記被加熱物の放射エネルギー量で前記被加熱物の温度を検知する温度検知手段と、前記材質判定手段により検出した前記被加熱物の材質に応じて前記温度検知手段の検出値を補正する温度補正手段と、前記温度補正手段による補正温度に応じて前記インバータ回路の出力の大きさを制御する出力制御手段とを備え、前記温度補正手段は、前記ステンレス領域の場合の前記温度検知手段の検出値と前記被加熱物の温度との相関を基準値として前記ステンレス領域の場合の補正温度とし、前記アルミ領域の場合は前記基準値に第１の所定値を減算して補正温度とし、前記鉄領域の場合は前記基準値に第２の所定値を加算して補正温度として補正する誘導加熱調理器を実現することができる。 Invention of claim 1, an induction heating coil for heating the generating a high-frequency magnetic field object to be heated, an inverter circuit for supplying a high-frequency current to the induction heating coil, to determine the material of the object to be heated aluminum A material determining means for detecting a region, a stainless steel region, and an iron region; a temperature detecting means for detecting a temperature of the heated object by an amount of radiant energy of the heated object; and a heating object detected by the material determining means. comprising a temperature correction means for correcting the detected value of the temperature sensing means in accordance with the material, and an output control means for controlling the magnitude of the output of said inverter circuit in accordance with the correction temperature by the temperature correcting means, the temperature correction The means uses the correlation between the detected value of the temperature detection means for the stainless steel region and the temperature of the object to be heated as a reference value as a correction temperature for the stainless steel region, For Mi region first by subtracting a predetermined value as the correction temperature to said reference value, the induction heating cooker when the iron region to correct a correction temperature by adding a second predetermined value to the reference value Can be realized.

また、被加熱物の材質の影響無く高精度に被加熱物の温度を所定温度に維持することができる。 In addition, the temperature of the object to be heated can be maintained at a predetermined temperature with high accuracy without being affected by the material of the object to be heated.

また、被加熱物の材質の影響なく高精度で即応性の良い温度制御を実現することができる。 In addition, temperature control with high accuracy and good responsiveness can be realized without being affected by the material of the object to be heated.

請求項２に記載の発明は、材質検出手段が誘導加熱コイルが発生する高周波電流あるいは高周波電圧と、電源電流との関係から被加熱物の材質を検出するものである。 According to a second aspect of the present invention, the material detecting means detects the material of the object to be heated from the relationship between the high-frequency current or high-frequency voltage generated by the induction heating coil and the power supply current.

（実施例１）
図１〜図５を用いて本発明の一実施例について説明する。図１において、１は鍋やフライパン等の被加熱物、２は被加熱物１を乗せるトッププレート、３は高周波磁界を発生する加熱コイル、４は加熱コイル３に高周波電流を供給するインバータ回路、５はインバータ回路の出力の大きさを制御する出力制御手段、６は被加熱物１の温度を放射エネルギー量で検知する温度検知手段、７はインバータ回路４の電源電流、高周波出力電圧から被加熱物１の材質を検知する材質検出手段、８は材質検出手段７の検知結果から温度検知手段６の検知温度を補正する温度補正手段、９は被加熱物１の過加熱を防止するため上限温度をあらかじめ記憶する所定温度記憶手段、１０は使用者が被加熱物１の温度を設定する温度設定入力手段、これらにより誘導加熱調理器が構成されている。インバータ回路４の一例は図２に示すように、商用電源を整流する整流回路１１、パワー半導体素子２個からなるプッシュプル構成の高周波スイッチング回路１２、この高周波スイッチング回路１２の２個のパワー素子を交互にＯＮ／ＯＦＦを制御するドライブ回路１３で実現されている。そして、出力制御手段５は前記ドライブ回路が交互にＯＮ／ＯＦＦする周期を制御することによりインバータ回路４から加熱コイル３に供給する出力の大きさを制御することができる。温度検知手段６は図３に示すように光半導体素子１４と増幅回路１５とから構成される光学式の非接触温度センサで、図中の矢印で示すように被加熱物１から放射される放射エネルギーの量に応じて変化する出力電圧によって温度を検知することができる。出力制御手段５は温度検知手段６の検出値を基にインバータ回路４の出力の大きさを制御することによって被加熱物１の温度を自在に制御することができる。この光学式の非接触温度センサを用いた温度制御システムは、サーミスタ等の接触式温度センサに比べて即応性の良い高精度の温度制御を実現することができる。ところが次に説明するように被加熱物１の材質による放射率の違いにより、検知温度に誤差が生じるという課題があった。 (Example 1)
An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, 1 is a heated object such as a pan or a frying pan, 2 is a top plate on which the heated object 1 is placed, 3 is a heating coil that generates a high-frequency magnetic field, 4 is an inverter circuit that supplies a high-frequency current to the heating coil 3, 5 is an output control means for controlling the magnitude of the output of the inverter circuit, 6 is a temperature detection means for detecting the temperature of the heated object 1 by the amount of radiant energy, and 7 is heated from the power supply current and high frequency output voltage of the inverter circuit 4 material detection means for detecting the material of the object 1, temperature correction means 8 to correct the detected temperature of the temperature detecting means 6 from the detection result of the means 7 out material detection, 9 to prevent excessive heating of the article to be heated 1 Predetermined temperature storage means for storing the upper limit temperature in advance, 10 is a temperature setting input means for the user to set the temperature of the article 1 to be heated, and these constitute an induction heating cooker. As shown in FIG. 2, an example of the inverter circuit 4 includes a rectifier circuit 11 for rectifying a commercial power supply, a high-frequency switching circuit 12 having a push-pull configuration composed of two power semiconductor elements, and two power elements of the high-frequency switching circuit 12. This is realized by a drive circuit 13 that alternately controls ON / OFF. And the output control means 5 can control the magnitude | size of the output supplied to the heating coil 3 from the inverter circuit 4 by controlling the period when the said drive circuit turns ON / OFF alternately. The temperature detecting means 6 is an optical non-contact temperature sensor composed of an optical semiconductor element 14 and an amplifier circuit 15 as shown in FIG. 3, and radiation emitted from the object 1 to be heated as indicated by an arrow in the figure. The temperature can be detected by an output voltage that changes according to the amount of energy. The output control means 5 can freely control the temperature of the object to be heated 1 by controlling the magnitude of the output of the inverter circuit 4 based on the detection value of the temperature detection means 6. This temperature control system using an optical non-contact temperature sensor can realize highly accurate temperature control with quick response compared to a contact temperature sensor such as a thermistor. However, as described below, there is a problem that an error occurs in the detected temperature due to a difference in emissivity depending on the material of the article 1 to be heated.

図４は被加熱物１の温度と温度検知手段６の検知温度との相関を示している。温度検知手段６の検知温度は被加熱物１の温度と比例関係にあるが、被加熱物１の材質によって検知温度と被加熱物１の温度に誤差が発生してしまう。図４では被加熱物１の温度が１００℃の例を示しているが、被加熱物１の材質が鉄、ステンレス、アルミの場合で、被加熱物１の実際の検知温度は９０℃、１００℃、１１０℃となっている。この誤差は、図５に示すように被加熱物１の材質によって放射率が異なるために発生してしまう。温度検知手段６と被加熱物１の温度の相関をステンレスを基準に決定すると、アルミは放射率が低いので温度検知手段６の検知温度は実際の被加熱物１の温度より高く検知してしまう、また鉄は放射率が高いので温度検知手段６の検知温度は実際の被加熱物１の温度より低く検知してしまう。 FIG. 4 shows the correlation between the temperature of the article 1 to be heated and the detected temperature of the temperature detecting means 6. The detected temperature of the temperature detecting means 6 is proportional to the temperature of the object to be heated 1, but an error occurs between the detected temperature and the temperature of the object to be heated 1 depending on the material of the object to be heated 1. FIG. 4 shows an example in which the temperature of the object to be heated 1 is 100 ° C., but when the material of the object to be heated 1 is iron, stainless steel, or aluminum, the actual detected temperature of the object to be heated 1 is 90 ° C., 100 ° C and 110 ° C. This error occurs because the emissivity differs depending on the material of the article 1 to be heated as shown in FIG. If the correlation between the temperature detection means 6 and the temperature of the object to be heated 1 is determined based on stainless steel, aluminum has a low emissivity, so that the temperature detected by the temperature detection means 6 is detected higher than the actual temperature of the object to be heated 1. Moreover, since iron has a high emissivity, the temperature detected by the temperature detecting means 6 is detected lower than the actual temperature of the object 1 to be heated.

この様な温度検知の誤差の補正方法を次に説明する。図６は材質検出手段７の一例を示している。高周波電圧検知回路１７は加熱コイル３に直列に接続されているコンデンサ１８の両端電圧を抵抗１９の分圧で検出している。また電源電流検知回路２０はインバータ回路４への電源電流をカレントトランス２１と抵抗２２で検出している。材質検出手段（材質判定手段）７は高周波電圧検知回路１７の検出値と電源電流検知回路２０の検出値とから被加熱物１の材質を判定する。この判定方法を図７を基に説明する。図７の実線は出力制御手段５がドライブ回路１３の制御周期を所定範囲変化させてインバータ回路４の出力を制御した時の電源電流と出力電圧との変化の軌跡を示している。図７から分かるように電源電流と出力電圧の変化の軌跡は被加熱物１の材質によって特徴的な動きをする。よって図７の点線で示すように領域Ｉ（磁性ステンレス）、領域ＩＩ（鉄）領域ＩＩＩ（非磁性ステンレス）、領域ＩＶ（アルミ）に区分して、前記電源電流と出力電圧の変化の軌跡の終点が属する領域によって被加熱物１の材質を判定することができる。温度補正手段８は被加熱物１の材質がステンレスの場合の温度検知手段６の検出値と被加熱物１の温度との相関を基準値として、材質判定手段７の判定結果がステンレスの場合は基準値を、判定結果がアルミの場合は基準値−１０℃を、判定結果が鉄の場合は基準値＋１０℃を、それぞれ補正温度とすることにより被加熱物１の材質の影響を無くして正しい被加熱物１の温度を出力制御手段５に出力することができる。出力制御手段５は温度補正手段６の検知温度に応じてインバータ回路４の出力の大きさを制御することにより、被加熱物１の材質の影響なく高精度で即応性の良い温度制御を実現することができる。 Next, a method for correcting such temperature detection error will be described. Figure 6 shows an example of a means 7 out material detection. The high-frequency voltage detection circuit 17 detects the voltage across the capacitor 18 connected in series with the heating coil 3 by the divided voltage of the resistor 19. The power supply current detection circuit 20 detects a power supply current to the inverter circuit 4 with a current transformer 21 and a resistor 22. Material detection means ( material determination means ) 7 determines the material of the article 1 to be heated from the detection value of the high-frequency voltage detection circuit 17 and the detection value of the power supply current detection circuit 20. This determination method will be described with reference to FIG. The solid line in FIG. 7 shows the locus of change between the power supply current and the output voltage when the output control means 5 controls the output of the inverter circuit 4 by changing the control cycle of the drive circuit 13 within a predetermined range. As can be seen from FIG. 7, the locus of changes in the power supply current and the output voltage has a characteristic movement depending on the material of the article 1 to be heated. Therefore, as shown by the dotted line in FIG. 7, the region I (magnetic stainless steel), the region II (iron), the region III (nonmagnetic stainless steel), and the region IV (aluminum) are divided into the locus of changes in the power supply current and the output voltage. The material of the article to be heated 1 can be determined by the region to which the end point belongs. The temperature correction means 8 uses the correlation between the detected value of the temperature detection means 6 and the temperature of the heated object 1 when the material of the heated object 1 is stainless steel as a reference value, and when the judgment result of the material judging means 7 is stainless steel The reference value is correct when the determination result is aluminum and the reference value is −10 ° C., and when the determination result is iron, the reference value is + 10 ° C., and the correction temperature is used to eliminate the influence of the material of the object 1 to be heated. The temperature of the article to be heated 1 can be output to the output control means 5. The output control means 5 controls the magnitude of the output of the inverter circuit 4 in accordance with the temperature detected by the temperature correction means 6, thereby realizing highly accurate and responsive temperature control without being affected by the material of the article 1 to be heated. be able to.

また出力制御手段５は図１に示すように、温度設定入力手段９で使用者により設定された設定温度と、温度補正手段８による補正温度との大小比較を行い、補正温度が設定温度より高いとインバータ回路４の出力を最大にし、また補正温度が設定温度より高いとインバータ回路４の出力を小さくする。この動作を繰り返すことにより、被加熱物１の材質の影響無く、被加熱物１の温度を高精度に設定温度に維持することができる。よって、例えば揚げ物調理のように被加熱物１の温度安定性が調理性能に大きく影響するメニューにおいても、本実施例の誘導加熱調理器では油の温度を精度良く設定温度に維持することができるので、簡単に上手な揚げ物調理を実現することができる。また、制御手段５は、所定温度記憶手段１０にあらかじめ設定されている所定温度と温度補正手段８の検知温度との大小比較を行い、検知温度が所定温度以上になると、インバータ回路４の出力を停止あるいは抑制することにより、被加熱物１が過加熱により必要以上の高温になることを防止することができる。また被加熱物１の温度を高精度に検知することができるので、過加熱防止においても、必要以上に低い温度で加熱の停止や抑制をすることが無く、使い勝手の良い誘導加熱調理器を提供することができる。 Further, as shown in FIG. 1, the output control means 5 compares the set temperature set by the user with the temperature setting input means 9 and the correction temperature set by the temperature correction means 8, and the correction temperature is higher than the set temperature. When the correction temperature is higher than the set temperature, the output of the inverter circuit 4 is reduced. By repeating this operation, the temperature of the object to be heated 1 can be maintained at the set temperature with high accuracy without being affected by the material of the object to be heated 1. Therefore, for example, in the menu where the temperature stability of the object to be heated 1 greatly affects the cooking performance such as fried food cooking, the temperature of the oil can be accurately maintained at the set temperature in the induction heating cooker of the present embodiment. Therefore, you can easily achieve good fried food cooking. Further, the control means 5 compares the predetermined temperature preset in the predetermined temperature storage means 10 with the detected temperature of the temperature correction means 8, and outputs the output of the inverter circuit 4 when the detected temperature becomes equal to or higher than the predetermined temperature. By stopping or suppressing, it is possible to prevent the heated object 1 from being heated to an unnecessarily high temperature due to overheating. In addition, since the temperature of the object to be heated 1 can be detected with high accuracy, it is possible to provide an induction heating cooker that is easy to use without stopping or suppressing heating at an unnecessarily low temperature for preventing overheating. can do.

本発明の実施例の構成を示す図The figure which shows the structure of the Example of this invention. 本発明のインバータ回路を説明する図The figure explaining the inverter circuit of this invention 本発明の温度検知手段を説明する図The figure explaining the temperature detection means of this invention 本発明の温度検知手段の検知誤差を説明する図The figure explaining the detection error of the temperature detection means of this invention 本発明の被加熱物の材質と放射率の関係を表す図The figure showing the relationship between the material of the to-be-heated material of this invention, and an emissivity 本発明の材質検知手段を説明する図The figure explaining the material detection means of this invention 本発明の材質検知手段を説明する図The figure explaining the material detection means of this invention 従来の技術の構成を説明する図The figure explaining the structure of the prior art

Explanation of symbols

１被加熱物
３加熱コイル
４インバータ回路
５出力制御手段
６温度検知手段
７材質検出手段（材質判定手段）
８温度補正手段
９所定温度記憶手段
１０温度設定入力手段
１７高周波電圧検知回路
２０電源電流検知回路 DESCRIPTION OF SYMBOLS 1 Heated object 3 Heating coil 4 Inverter circuit 5 Output control means 6 Temperature detection means 7 Material detection means (material judgment means)
8 Temperature correction means 9 Predetermined temperature storage means 10 Temperature setting input means 17 High frequency voltage detection circuit 20 Power supply current detection circuit

Claims

An induction heating coil for heating the generating a high-frequency magnetic field object to be heated, the induction and the inverter circuit for supplying a high-frequency current to the heating coil, wherein to determine the material of the object to be heated detected aluminum regions stainless region iron region a material determining means for the temperature detection means for detecting the temperature of the heated object with radiant energy of the object to be heated, the temperature sensing means in accordance with the material of the object to be heated detected by the material determining means Temperature correction means for correcting the detected value, and output control means for controlling the magnitude of the output of the inverter circuit in accordance with the temperature corrected by the temperature correction means, the temperature correction means in the case of the stainless steel region The correction value in the case of the stainless steel region as a reference value based on the correlation between the detection value of the temperature detection means and the temperature of the object to be heated, and the reference value in the case of the aluminum region First by subtracting a predetermined value as the correction temperature, the induction heating cooker for correcting a corrected temperature by adding a second predetermined value to the reference value in the case of the iron area.

Material detection means, induction heating cooker according the high-frequency current or high-frequency voltage induction heating coil generates, from the relationship between the supply current to claim 1 for detecting the material of the object to be heated.