JP4432498B2 - Induction heating inverter controller - Google Patents

Induction heating inverter controller Download PDF

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JP4432498B2
JP4432498B2 JP2004006623A JP2004006623A JP4432498B2 JP 4432498 B2 JP4432498 B2 JP 4432498B2 JP 2004006623 A JP2004006623 A JP 2004006623A JP 2004006623 A JP2004006623 A JP 2004006623A JP 4432498 B2 JP4432498 B2 JP 4432498B2
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circuit
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inverter main
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inverter
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隆宣 角垣
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Fuji Electric Co Ltd
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/04—Sources of current

Description

この発明は、直流電源と、自己消弧形素子とダイオードの逆並列回路をブリッジ接続してなるインバータ主回路と、加熱コイル及び共振コンデンサからなる共振回路と、前記インバータ主回路を制御する制御回路とを備え、前記加熱コイル上の鍋を加熱する誘導加熱インバータの制御装置に関する。 The present invention relates to a DC power supply, an inverter main circuit formed by bridge-connecting an antiparallel circuit of a self-extinguishing element and a diode, a resonance circuit including a heating coil and a resonance capacitor, and a control circuit for controlling the inverter main circuit. It is related with the control apparatus of the induction heating inverter which heats the pan on the said heating coil.

図４は、下記特許文献１に記載の回路構成などを含む、この種の誘導加熱インバータの従来例を示す回路構成図であり、この図において、１は整流電源などの直流電源、２，３はそれぞれＩＧＢＴ２ａ，３ａとダイオード２ｂ，３ｂとを逆並列接続してなる半導体スイッチ、４，５は共振コンデンサ、６は直流電源１の端子電圧を検出する直流電圧検出器、７は直流電源１の出力電流を検出する直流電流検出器、８は加熱コイル２０の上に設置される被加熱物としての鍋２１を誘導加熱するために加熱コイル２０に流れる高周波の交流電流を検出する交流電流検出器、１０は後述の制御回路であり、この回路構成では半導体スイッチ２と半導体スイッチ３とでハーフブリッジ接続のインバータ主回路を形成し、さらに、共振コンデンサ４，５と加熱コイル２０とで共振回路を形成している。   FIG. 4 is a circuit configuration diagram showing a conventional example of this type of induction heating inverter including the circuit configuration described in Patent Document 1 below. In this figure, 1 is a DC power source such as a rectifying power source, Is a semiconductor switch formed by connecting IGBTs 2a and 3a and diodes 2b and 3b in antiparallel, 4 and 5 are resonant capacitors, 6 is a DC voltage detector for detecting the terminal voltage of the DC power supply 1, and 7 is DC power supply 1 A DC current detector for detecting an output current, 8 is an AC current detector for detecting a high-frequency AC current flowing in the heating coil 20 in order to inductively heat the pan 21 as an object to be heated installed on the heating coil 20. Reference numeral 10 denotes a control circuit which will be described later. In this circuit configuration, the semiconductor switch 2 and the semiconductor switch 3 form a half-bridge connected inverter main circuit. Form a resonance circuit with the heating coil 20.

この制御回路１０には鍋２１の加熱電力を設定する電力設定器１１と、直流電圧検出器６，直流電流検出器７それぞれの検出値から鍋２１への加熱電力の演算値を導出する電力演算器１２と、電力設定器１１の設定値と電力演算器１２の演算値との偏差に基づいて前記インバータ主回路が出力すべき電力の調節演算をする電力調節器１３と、電力調節器１３の出力値と交流電流検出器８，整流器１４を介して得られる前記インバータ主回路が出力する電流の検出値（直流量）との偏差に基づいて前記インバータ主回路が出力すべき電流の調節演算を行う電流調節器１５と、電流調節器１５の出力値と交流電流検出器８の検出値（交流量）とから前記インバータ主回路が出力する電圧と電流の位相差（γ）が所望の値に調整された半導体スイッチ２，３への駆動信号を出力するγ制御回路１６と、前記駆動信号を半導体スイッチ２，３それぞれへのオン・オフ信号に分解するパルス分配器１７と、前記オン・オフ信号を半導体スイッチ２，３のＩＧＢＴ２ａ，３ａへのゲート信号に変換するゲート駆動回路１８とを備えている。   The control circuit 10 includes a power setting unit 11 for setting the heating power of the pot 21, and a power calculation for deriving a calculated value of the heating power to the pot 21 from the detected values of the DC voltage detector 6 and the DC current detector 7. A power regulator 13 that performs a regulation calculation of power to be output from the inverter main circuit based on a deviation between a set value of the power setter 11 and a calculated value of the power calculator 12. Based on the deviation between the output value and the detected value (DC amount) of the current output from the inverter main circuit obtained via the AC current detector 8 and the rectifier 14, the adjustment operation of the current to be output by the inverter main circuit is performed. The phase difference (γ) of the voltage and current output from the inverter main circuit is set to a desired value from the current regulator 15 to be performed, the output value of the current regulator 15 and the detection value (AC amount) of the AC current detector 8. Tuned semiconductor switch Γ control circuit 16 that outputs a drive signal to 2 and 3, a pulse distributor 17 that decomposes the drive signal into an on / off signal to each of semiconductor switches 2 and 3, and the on / off signal to semiconductor switch 2 , 3 is provided with a gate drive circuit 18 for converting into gate signals to the IGBTs 2a, 3a.

図４に示した誘導加熱インバータにおいて、前記共振回路の共振周波数が例えば２０ｋＨｚ程度に整定されたとすると、この誘導加熱インバータの起動時には、制御回路１０から前記インバータ主回路の出力周波数を５０ｋＨｚ程度に設定して該インバータ主回路を起動させ、起動完了時には、鍋２１への加熱電力が指令される値に達する周波数まで出力周波数を下降させるが、このとき、前記出力周波数の変化範囲を２５〜５０ｋＨｚ程度にすることで、前記インバータ主回路から前記共振回路への出力電流に対する該インバータ主回路の出力電圧が進み位相となり、その位相差（γ）は所望の値の状態に保たれ、この誘導加熱インバータが安定に動作することが知られている。   In the induction heating inverter shown in FIG. 4, assuming that the resonance frequency of the resonance circuit is set to about 20 kHz, for example, the output frequency of the inverter main circuit is set to about 50 kHz from the control circuit 10 when the induction heating inverter is started. Then, the inverter main circuit is activated, and when the activation is completed, the output frequency is lowered to a frequency at which the heating power to the pot 21 reaches a commanded value. At this time, the change range of the output frequency is about 25 to 50 kHz. Thus, the output voltage of the inverter main circuit with respect to the output current from the inverter main circuit to the resonance circuit becomes a leading phase, and the phase difference (γ) is maintained at a desired value, and this induction heating inverter Is known to operate stably.

なお、上述の制御回路１０を形成するそれぞれの機能は周知の技術により構成できるので、その詳細構成の説明を省略する。
特開平１１−５４２４９号公報 （第２頁〜第４頁、第１図） Note that each function forming the above-described control circuit 10 can be configured by a well-known technique, and thus a detailed description thereof is omitted.
Japanese Patent Laid-Open No. 11-54249 (pages 2 to 4 and FIG. 1)

この種の誘導加熱インバータにおいて、その制御機能をマイクロコンピュータにより具現することが一般的になってきているが、近年、マイクロコンピュータの演算処理速度の高速化に伴い、例えば、関数演算の高速処理が低価格のマイクロコンピュータでも可能となってきている。   In this type of induction heating inverter, it has become common to implement the control function by a microcomputer. However, in recent years, with the increase in the processing speed of microcomputers, for example, high-speed processing of function operations has been performed. Even low-cost microcomputers are becoming possible.

すなわち、この発明の目的は、マイクロコンピュータの関数演算の高速処理能力を利用することにより、この種の誘導加熱インバータ全体の小型化・コストダウンを可能にする誘導加熱インバータの制御方法を提供することにある。   That is, an object of the present invention is to provide a control method of an induction heating inverter that makes it possible to reduce the size and cost of this type of induction heating inverter as a whole by utilizing the high-speed processing capability of the microcomputer's function operation. It is in.

この発明は直流電源と、自己消弧形素子とダイオードの逆並列回路をブリッジ接続してなるインバータ主回路と、加熱コイル及び共振コンデンサからなる共振回路と、前記インバータ主回路を制御する制御回路とを備え、前記インバータ主回路から前記共振回路への出力電流に対する該インバータ主回路の出力電圧が進み位相になる周波数領域の交流電力により前記加熱コイル上の被加熱物を誘導加熱する誘導加熱インバータにおいて、
前記制御回路に、前記直流電源からインバータ主回路に入力される入力直流電圧（Ｖ DC ）を検出する入力直流電圧検出器と、前記インバータ主回路の出力電流（Ｉｏ）を検出する出力電流検出器と、前記出力電流検出器の検出波形および前記インバータ主回路の自己消弧形素子への駆動信号に基づいて前記インバータ主回路の出力電圧―出力電流間の位相差（γ）を求めるγ角計測回路と、前記入力直流電圧検出器により検出した入力直流電圧（Ｖ DC ）と前記出力電流検出器により検出した出力電流（Ｉｏ）とγ角計測回路により求めた出力電圧―出電流間の位相差（γ）の余弦とを乗算して前記被加熱物への加熱電力（Ｐ）を求める電力演算器とを設けたことを特徴とする。 The present invention relates to a DC power supply, an inverter main circuit formed by bridge-connecting an antiparallel circuit of a self-extinguishing element and a diode, a resonance circuit including a heating coil and a resonance capacitor, and a control circuit for controlling the inverter main circuit; An induction heating inverter that induction-heats an object to be heated on the heating coil with AC power in a frequency region in which an output voltage of the inverter main circuit is in a lead phase with respect to an output current from the inverter main circuit to the resonance circuit ,
The control circuit includes an input DC voltage detector that detects an input DC voltage (V DC ) input from the DC power source to the inverter main circuit, and an output current detector that detects an output current (Io) of the inverter main circuit. And γ angle measurement for obtaining a phase difference (γ) between the output voltage and output current of the inverter main circuit based on the detection waveform of the output current detector and the drive signal to the self-extinguishing element of the inverter main circuit Circuit, input DC voltage (V DC ) detected by the input DC voltage detector, output current (Io) detected by the output current detector, and phase difference between output voltage and output current obtained by the γ angle measuring circuit A power calculator is provided that multiplies the cosine of (γ) to determine the heating power (P) for the object to be heated .

この種の誘導加熱インバータにおいて、従来は前記加熱コイル上の鍋への加熱電力を前記インバータ回路への入力直流電圧と入力直流電流とから導出していたが、この発明では前記加熱電力を前記インバータ主回路への入力直流電圧と前記出力電流と前記位相差とに基づいて導出することで、直流絶縁が要求されることなどから大型で高価な直流電流検出器を省略することができる。   In this type of induction heating inverter, conventionally, the heating power for the pan on the heating coil was derived from the input DC voltage and the input DC current to the inverter circuit. In the present invention, the heating power is derived from the inverter. By deriving based on the input DC voltage to the main circuit, the output current, and the phase difference, a large and expensive DC current detector can be omitted because DC insulation is required.

図１は、この発明の実施例を示す誘導加熱インバータの制御装置の回路構成図であり、この図において、図４に示した従来例構成と同一機能を有するものには同一符号を付している。 FIG. 1 is a circuit configuration diagram of a control device for an induction heating inverter showing an embodiment of the present invention. In this figure, components having the same functions as those of the conventional configuration shown in FIG. Yes.

すなわち、図１に示した誘導加熱インバータにおいては直流電流検出器７が省略され、制御回路３０として電力設定器１１，電力調節器１３，整流回路１４，電流調節器１５，γ制御回路１６，パルス分配器１７，ゲート駆動回路１８の他に、電力演算器１２に代えて、電力演算器３１とγ角計測回路３２とを備えている。   That is, in the induction heating inverter shown in FIG. 1, the DC current detector 7 is omitted, and the control circuit 30 includes a power setting unit 11, a power regulator 13, a rectifier circuit 14, a current regulator 15, a γ control circuit 16, and a pulse. In addition to the distributor 17 and the gate drive circuit 18, a power calculator 31 and a γ angle measuring circuit 32 are provided instead of the power calculator 12.

図２は、図１に示したγ角計測回路３２の詳細回路構成図であり、このγ角計測回路３２には波形整形回路３２ａとγ時間計測回路３２ｂと周期計測回路３２ｃと除算演算回路３２ｄとを備えている。   FIG. 2 is a detailed circuit configuration diagram of the γ angle measurement circuit 32 shown in FIG. 1. The γ angle measurement circuit 32 includes a waveform shaping circuit 32a, a γ time measurement circuit 32b, a period measurement circuit 32c, and a division calculation circuit 32d. And.

また図３は、図２に示したγ計測回路３２の動作を説明する波形図であり、出力電流検出器８で検出される正弦波状の出力電流波形は、波形整形回路３２ａによりほぼ零クロス点で変化する論理信号に変換され、γ時間計測回路３２ｂでは前記波形整形出力とパルス分配器１７が出力するＩＧＢＴ３ａへの論理レベルの駆動信号との論理積演算を行い、この演算結果の論理「Ｈ」レベルの継続時間をγ時間として計測する。また、周期計測回路３２ｃでは前記ＩＧＢＴ３ａへの駆動信号が論理「Ｌ」から「Ｈ」に変化する期間をＴ時間として計測し、除算演算回路３２では「γ角＝（γ／Ｔ）×３６０°」の演算を行い、この演算結果を電力演算回路３１へ出力している。なお、図３に示した動作波形例では前記電流波形が正から負に変化する時点でのγ角を計測しているが、負から正に変化する時点、若しくは双方の時点で行ってもよい。   FIG. 3 is a waveform diagram for explaining the operation of the γ measuring circuit 32 shown in FIG. 2. The sinusoidal output current waveform detected by the output current detector 8 is substantially zero crossed by the waveform shaping circuit 32a. The γ time measuring circuit 32b performs a logical product operation of the waveform shaping output and the logic level drive signal output to the IGBT 3a output from the pulse distributor 17, and the logical “H” The level duration is measured as γ time. The period measuring circuit 32c measures the period during which the drive signal to the IGBT 3a changes from logic "L" to "H" as T time, and the division operation circuit 32 measures "γ angle = (γ / T) × 360 °. ”And outputs the calculation result to the power calculation circuit 31. In the example of the operation waveform shown in FIG. 3, the γ angle at the time when the current waveform changes from positive to negative is measured. However, it may be performed at the time when the current waveform changes from negative to positive, or at both times. .

また、電力演算器３１では交流電流検出器８により検出される前記インバータ回路の出力電流の実効値を求め、この実効値（ＩO ）と、直流電圧検出器６により検出される前記インバータ主回路への入力直流電圧、すなわち、直流電源１の端子電圧（ＶDC）と、γ角計測回路３２により得られたγ角とにより、加熱コイル２０上の鍋２１への加熱電力の演算値（Ｐ）として、「Ｐ＝（ＶDC／２）×ＩO ×ｃｏｓγ」なる演算を行い、この演算結果を電力調節器１３へ出力している。
なお、直流電源１が例えば三相の全波整流波形出力の場合には、この整流電圧のピーク値をα倍（α＜１）すれば、平均値とみなすことができるので、例えば整流電圧のピーク値の約０．９倍した値を前記ＶDCとして、上記の演算を行えばよい。また、この電力演算器３１では上記三角関数などの関数演算を例えば２０μ秒程度の処理速度で行えることが望ましい。 The power calculator 31 obtains an effective value of the output current of the inverter circuit detected by the AC current detector 8, and calculates the effective value (I O ) and the inverter main circuit detected by the DC voltage detector 6. The calculated value (P) of the heating power to the pan 21 on the heating coil 20 based on the input DC voltage to the terminal, that is, the terminal voltage (V DC ) of the DC power source 1 and the γ angle obtained by the γ angle measuring circuit 32. ), The calculation “P = (V DC / 2) × I O × cos γ” is performed, and the calculation result is output to the power regulator 13.
When the DC power supply 1 is, for example, a three-phase full-wave rectified waveform output, if the peak value of this rectified voltage is multiplied by α (α <1), it can be regarded as an average value. The above calculation may be performed with a value obtained by multiplying the peak value by about 0.9 times as the VDC . Further, it is desirable that the power calculator 31 can perform a function calculation such as the above trigonometric function at a processing speed of, for example, about 20 μsec.

なお、図１に示したこの発明の誘導加熱インバータの回路構成ではインバータ主回路がハーフブリッジ接続の回路構成であるが、インバータ主回路がフルブリッジ接続の回路構成でもこの発明の制御方法を行うことができる。   In addition, in the circuit configuration of the induction heating inverter of the present invention shown in FIG. 1, the inverter main circuit is a half-bridge connection circuit configuration, but the control method of the present invention is performed even when the inverter main circuit is a full-bridge connection circuit configuration. Can do.

この発明の実施例を示す誘導加熱インバータの制御装置の回路構成図The circuit block diagram of the control apparatus of the induction heating inverter which shows the Example of this invention 図１の部分詳細回路構成図Partial detailed circuit configuration diagram of FIG. 図２の動作を説明する波形図Waveform diagram explaining the operation of FIG. 従来例を示す誘導加熱インバータの回路構成図Circuit diagram of induction heating inverter showing conventional example

１…直流電源、２，３…半導体スイッチ、４，５…共振コンデンサ、６…直流電圧検出器、７…直流電流検出器、８…交流電流検出器、１０…制御装置、１１…電力設定器、１２…電力演算器、１３…電力調節器、１４…整流回路、１５…電流調節器、１６…γ制御回路、１７…パルス分配器、１８…ゲート駆動回路、２０…加熱コイル、２１…鍋、３０…制御回路、３１…電力演算器、３２…γ角計測回路。
DESCRIPTION OF SYMBOLS 1 ... DC power supply, 2, 3 ... Semiconductor switch, 4, 5 ... Resonance capacitor, 6 ... DC voltage detector, 7 ... DC current detector, 8 ... AC current detector, 10 ... Control device, 11 ... Power setting device DESCRIPTION OF SYMBOLS 12 ... Power calculator, 13 ... Power regulator, 14 ... Rectifier circuit, 15 ... Current regulator, 16 ... γ control circuit, 17 ... Pulse distributor, 18 ... Gate drive circuit, 20 ... Heating coil, 21 ... Pan , 30... Control circuit, 31... Power calculator, 32.

Claims (1)

直流電源と、自己消弧形素子とダイオードの逆並列回路をブリッジ接続してなるインバータ主回路と、加熱コイル及び共振コンデンサからなる共振回路と、前記インバータ主回路を制御する制御回路とを備え、前記インバータ主回路から前記共振回路への出力電流に対する該インバータ主回路の出力電圧が進み位相になる周波数領域の交流電力により前記加熱コイル上の被加熱物を誘導加熱する誘導加熱インバータにおいて、
前記制御回路に、前記直流電源からインバータ主回路に入力される入力直流電圧（Ｖ DC ）を検出する入力直流電圧検出器と、前記インバータ主回路の出力電流（Ｉｏ）を検出する出力電流検出器と、前記出力電流検出器の検出波形および前記インバータ主回路の自己消弧形素子への駆動信号に基づいて前記インバータ主回路の出力電圧―出力電流間の位相差（γ）を求めるγ角計測回路と、前記入力直流電圧検出器により検出した入力直流電圧（Ｖ DC ）と前記出力電流検出器により検出した出力電流（Ｉｏ）とγ角計測回路により求めた出力電圧―出電流間の位相差（γ）の余弦とを乗算して前記被加熱物への加熱電力（Ｐ）を求める電力演算器とを設けたことを特徴とする誘導加熱インバータの制御装置。 A DC power supply, an inverter main circuit formed by bridge-connecting an antiparallel circuit of a self-extinguishing element and a diode, a resonance circuit including a heating coil and a resonance capacitor, and a control circuit for controlling the inverter main circuit , In an induction heating inverter that induction-heats an object to be heated on the heating coil with AC power in a frequency region in which an output voltage of the inverter main circuit is in a lead phase with respect to an output current from the inverter main circuit to the resonance circuit ,
The control circuit includes an input DC voltage detector that detects an input DC voltage (V DC ) input from the DC power source to the inverter main circuit, and an output current detector that detects an output current (Io) of the inverter main circuit. And γ angle measurement for obtaining a phase difference (γ) between the output voltage and output current of the inverter main circuit based on the detection waveform of the output current detector and the drive signal to the self-extinguishing element of the inverter main circuit Circuit, input DC voltage (V DC ) detected by the input DC voltage detector, output current (Io) detected by the output current detector, and phase difference between output voltage and output current obtained by the γ angle measuring circuit A control device for an induction heating inverter, comprising: a power calculator that multiplies a cosine of (γ) to obtain heating power (P) for the object to be heated.
JP2004006623A 2004-01-14 2004-01-14 Induction heating inverter controller Expired - Fee Related JP4432498B2 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103904871A (en) * 2014-03-25 2014-07-02 深圳麦格米特电气股份有限公司 Control method of high-frequency heating power switch tube protection circuit

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005050037A1 (en) * 2005-10-14 2007-05-24 E.G.O. Elektro-Gerätebau GmbH Induction heater and method for operating such
CN101636014A (en) * 2009-08-12 2010-01-27 苏州市春和电器有限公司 Low power consumption standby circuit device of induction cooker
FR2954887B1 (en) * 2009-12-31 2012-01-20 Fagorbrandt Sas METHOD AND DEVICE FOR DETERMINING THE INSTANT POWER DELIVERED BY INDUCTION MEANS ASSOCIATED WITH A HEATING CONTAINER

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103904871A (en) * 2014-03-25 2014-07-02 深圳麦格米特电气股份有限公司 Control method of high-frequency heating power switch tube protection circuit
CN103904871B (en) * 2014-03-25 2016-09-07 深圳麦格米特电气股份有限公司 The control method of high-frequency heating power switching tube protection circuit

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