JP2002299033A - Power supply for driving magnetron - Google Patents
Power supply for driving magnetronInfo
- Publication number
- JP2002299033A JP2002299033A JP2001095748A JP2001095748A JP2002299033A JP 2002299033 A JP2002299033 A JP 2002299033A JP 2001095748 A JP2001095748 A JP 2001095748A JP 2001095748 A JP2001095748 A JP 2001095748A JP 2002299033 A JP2002299033 A JP 2002299033A
- Authority
- JP
- Japan
- Prior art keywords
- power supply
- voltage
- magnetron
- oscillation
- driving
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Control Of High-Frequency Heating Circuits (AREA)
Abstract
Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【発明の属する技術分野】本発明は、電子レンジなどの
マグネトロンを負荷とするマグネトロン駆動用電源に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for driving a magnetron such as a microwave oven.
【０００２】[0002]
【従来の技術】従来のマグネトロン駆動用電源について
図面を用いて説明する。図１３は従来のマグネトロン駆
動用電源の回路図である。従来のマグネトロン駆動用電
源は交流である商用電源１を一旦ダイオードブリッジ２
で直流電圧に変換し、この直流電圧を半導体スイッチ素
子３，４のオンオフによってインバータ回路５は高圧ト
ランス６の１次巻線に高周波電圧を発生し、高圧トラン
ス６は２次巻線に高周波高電圧を励起する。この高周波
高電圧は高圧整流回路７によって直流高電圧に整流さ
れ、マグネトロン８に印加される。マグネトロン８はこ
の直流高電圧で駆動され、２．４５GHzの電波を発生す
る。2. Description of the Related Art A conventional magnetron driving power supply will be described with reference to the drawings. FIG. 13 is a circuit diagram of a conventional magnetron driving power supply. A conventional magnetron drive power supply is a commercial power supply 1, which is an alternating current, and a diode bridge 2
The inverter circuit 5 generates a high-frequency voltage in the primary winding of the high-voltage transformer 6 by turning on and off the semiconductor switching elements 3 and 4, and the high-voltage transformer 6 applies a high-frequency voltage to the secondary winding. Excitation voltage. This high-frequency high voltage is rectified into a DC high voltage by the high-voltage rectifier circuit 7 and applied to the magnetron 8. The magnetron 8 is driven by the high DC voltage and generates a radio wave of 2.45 GHz.
【０００３】図１４は従来のマグネトロン駆動用電源の
動作波形を示した図である。商用電源１の交流電圧Ｖ１
はダイオードブリッジ２によって直流電圧に整流され
る。インダクタ９とコンデンサ１０は平滑回路を構成し
ているが、コンデンサ１０の容量はインバータ回路５の
サイズを小型化するために２０ｋHzから５０ｋHzで動作
するインバータ回路５に対して直流電圧を保持できる程
度の容量としており、商用電源１の周波数(５０Hzまた
は６０Hz)に対しては平滑する能力を有していない。こ
のためコンデンサ１０の電圧Ｖ１０は商用電源１を単に
全波整流した波形を示し、ほぼ０電圧から商用電源１の
最大電圧まで変動する脈動波形を示す。インバータ回路
５はこの脈動するコンデンサ１０の電圧Ｖ１０によって
動作するので、高圧トランス６の１次巻線に発生する高
周波電圧の包絡線波形はＶ６（Ｌｐ）に示すような波形
となりコンデンサ１０の電圧Ｖ１０が低い期間では同様
に低い電圧しか発生し得ない。FIG. 14 is a diagram showing operation waveforms of a conventional magnetron driving power supply. AC voltage V1 of commercial power supply 1
Is rectified by the diode bridge 2 into a DC voltage. The inductor 9 and the capacitor 10 form a smoothing circuit, but the capacity of the capacitor 10 is such that the DC voltage can be held for the inverter circuit 5 operating at 20 kHz to 50 kHz in order to reduce the size of the inverter circuit 5. It has a capacity and does not have the ability to smooth the frequency of the commercial power supply 1 (50 Hz or 60 Hz). For this reason, the voltage V10 of the capacitor 10 indicates a waveform obtained by simply performing full-wave rectification on the commercial power supply 1, and indicates a pulsating waveform that varies from almost zero voltage to the maximum voltage of the commercial power supply 1. Since the inverter circuit 5 operates with the pulsating voltage V10 of the capacitor 10, the envelope waveform of the high-frequency voltage generated in the primary winding of the high-voltage transformer 6 becomes a waveform as shown by V6 (Lp). However, only a low voltage can be generated during the low period.
【０００４】一方、マグネトロン８の動作特性は図１５
に示すようにアノードカソード間に所定の電圧以上が印
加されないとアノード電流が流れないような非線形な電
圧電流特性を示す。したがって、高圧トランス６の１次
巻線に発生する電圧が低い期間では２次巻線に励起され
る電圧も同時に低くなるためマグネトロン８に印加され
る電圧Ｖ８の波形は図に示すごとくＶAK(TH)に到達しな
くなる期間が発生する。この期間はマグネトロン８が発
振を停止しているため負荷であるマグネトロン８で電力
消費されないため商用電源１の電流Ｉ１は流れなくな
る。この結果商用電源１の電流Ｉ１の波形は図１４に示
すごとく電流が０となる期間を有する非常に歪を持った
波形となり、これが原因でマグネトロン駆動用電源の力
率の低下、入力電流に高調波電流を発生することにな
る。On the other hand, the operating characteristics of the magnetron 8 are shown in FIG.
As shown in FIG. 5, a non-linear voltage-current characteristic such that an anode current does not flow unless a predetermined voltage or more is applied between the anode and the cathode is exhibited. Accordingly, when the voltage generated in the primary winding of the high-voltage transformer 6 is low, the voltage excited in the secondary winding also decreases at the same time, and the waveform of the voltage V8 applied to the magnetron 8 is V AK ( There is a period when it does not reach TH) . During this period, since the magnetron 8 stops oscillating, power is not consumed by the magnetron 8, which is a load, so that the current I1 of the commercial power supply 1 stops flowing. As a result, the waveform of the current I1 of the commercial power supply 1 becomes a very distorted waveform having a period in which the current becomes 0 as shown in FIG. 14, and this causes a decrease in the power factor of the magnetron driving power supply and a higher harmonic than the input current. A wave current will be generated.
【０００５】このような課題に対して図１６に示す回路
構成のようにアクティブフィルタ回路１３をインバータ
回路５の前段に設け、入力電流の力率向上、高調波抑制
を図ったものが提案されている。アクティブフィルタ回
路１３はいわゆる昇圧チョッパ回路の構成をしており、
半導体スイッチ素子１７のオン時間比によって昇圧電圧
を制御することができる。In order to solve such a problem, an active filter circuit 13 is provided in front of the inverter circuit 5 as shown in FIG. 16 to improve the power factor of input current and suppress harmonics. I have. The active filter circuit 13 has a configuration of a so-called step-up chopper circuit.
The boosted voltage can be controlled by the ON time ratio of the semiconductor switch element 17.
【０００６】この場合の動作について図１７を用いて説
明する。商用電源１の電圧はＶ１に示すように交流電圧
波形を示している。アクティブフィルタ回路１３はダイ
オードブリッジ２によって交流電圧Ｖ１を全波整流した
電圧を半導体スイッチ素子１４のオンオフによって制御
することによってコンデンサ１５に昇圧電圧を発生す
る。この昇圧電圧Ｖ１５はコンデンサ１５の容量によっ
て脈動率は変化するが、図１３の構成におけるＶ１０の
ように完全に０まで低下しないようにすることができ
る。このため高圧トランス６の１次巻線に発生する電圧
Ｖ６（Ｌｐ）も商用電源１の電圧が０近傍であっても所
定の値以上を発生することができる。この結果マグネト
ロン８に印加する電圧は常に発振可能電圧以上を保持す
ることが可能となる。その結果、入力電流Ｉ１は図に示
すように０となる期間を持たない略正弦波状の波形とす
ることができ、入力力率の向上、高調波電流の抑制が可
能となる。The operation in this case will be described with reference to FIG. The voltage of the commercial power supply 1 shows an AC voltage waveform as indicated by V1. The active filter circuit 13 generates a boosted voltage at the capacitor 15 by controlling the voltage obtained by full-wave rectifying the AC voltage V1 by the diode bridge 2 by turning on and off the semiconductor switch element 14. Although the pulsation rate of the boosted voltage V15 changes depending on the capacitance of the capacitor 15, it is possible to prevent the boosted voltage V15 from dropping completely to zero unlike V10 in the configuration of FIG. Therefore, the voltage V6 (Lp) generated in the primary winding of the high-voltage transformer 6 can be equal to or higher than a predetermined value even when the voltage of the commercial power supply 1 is near zero. As a result, the voltage applied to the magnetron 8 can always be kept higher than the oscillating voltage. As a result, the input current I1 can have a substantially sinusoidal waveform that does not have a period during which it becomes 0 as shown in the figure, and the input power factor can be improved and the harmonic current can be suppressed.
【０００７】しかしながらこのような構成ではインバー
タ回路５にアクティブフィルタ回路１３を付加した構成
となり、電力変換の過程が整流→昇圧→高周波発生(イ
ンバータ回路)→高圧整流となるので電力変換の過程が
増加し、変換効率の低下と回路規模の増大が課題とな
る。However, in such a configuration, the active filter circuit 13 is added to the inverter circuit 5, and the power conversion process is rectification → boost → high frequency generation (inverter circuit) → high voltage rectification, so the power conversion process is increased. However, the conversion efficiency is reduced and the circuit scale is increased.
【０００８】そこで、さらに構成部品、回路機能の共用
化を図った構成のものが特開平１０−２７１８４６号公
報にて公開されている。図１８はこの発明の回路構成を
示した回路図である。この回路構成によって昇圧機能、
インバータ機能の動作を一度に行い、入力力率の向上と
回路構成の簡素化を目的としている。図１９、図２０は
回路動作を説明した図であり、図１９（ａ）〜（ｄ）は
半導体スイッチ素子Ｑ１、Ｑ２のオンオフによって各々
通電経路を説明した図であり、図２０はそれに対応した
動作波形図である。図１９、図２０を用いて回路動作に
ついて説明する。説明の都合上商用電源１の電圧極性が
図に示す方向で半導体スイッチ素子Ｑ２がオンの状態か
ら説明をはじめる。半導体スイッチ素子Ｑ２がオンの状
態では図１９（ａ）に示すようにコンデンサＣ２→商用
電源１→誘導性負荷回路１９→半導体スイッチ素子Ｑ２
の経路で電流が流れ、図２０（ａ）に示すように半導体
スイッチ素子Ｑ２の電流ＩQ2は単調に増加する。所定の
時間で半導体スイッチ素子Ｑ２をオフすると電流経路は
図１９（ｂ）の状態へ移り、ダイオードＤ２→商用電源
１→誘導性負荷回路１９→ダイオードＤ３→コンデンサ
Ｃ１の経路でコンデンサＣ１を充電する。誘導性負荷回
路１９に蓄えられたエネルギーをすべて放出するとコン
デンサＣ１を電源としてコンデンサＣ１→半導体スイッ
チ素子Ｑ１→誘導性負荷回路１９→商用電源１→コンデ
ンサＣ２で構成される図１９（ｃ）の経路で電流が流れ
る。所定の時間で半導体スイッチ素子Ｑ１をオフすると
誘導性負荷回路１９は同じ方向へ電流を流そうとするの
で図１９（ｄ）に示す経路（商用電源１→コンデンサＣ
２→ダイオードＤ４→誘導性負荷回路１９）で電流が流
れ、誘導性負荷回路１９に蓄えたエネルギーをコンデン
サＣ１へ充電する。誘導性負荷回路１９に蓄えたエネル
ギーがすべて放出されると再び図１９（ａ）の経路で電
流が流れ回路動作が継続する。特開平１０−２７１８４
６には開示されていないが、この動作を実現するために
はコンデンサＣ１とコンデンサＣ２の容量には式１で示
されるような容量関係が必要である。[0008] In view of this, a configuration for further sharing the components and circuit functions is disclosed in Japanese Patent Application Laid-Open No. Hei 10-271846. FIG. 18 is a circuit diagram showing a circuit configuration of the present invention. With this circuit configuration, the boost function,
The operation of the inverter function is performed at one time, with the aim of improving the input power factor and simplifying the circuit configuration. 19 and 20 are diagrams for explaining the circuit operation, and FIGS. 19 (a) to (d) are diagrams for explaining energization paths by turning on and off the semiconductor switch elements Q1 and Q2, respectively, and FIG. It is an operation waveform diagram. The circuit operation will be described with reference to FIGS. For convenience of description, the description will be started from the state where the semiconductor switch element Q2 is turned on with the voltage polarity of the commercial power supply 1 in the direction shown in the figure. When the semiconductor switching element Q2 is on, the capacitor C2 → the commercial power supply 1 → the inductive load circuit 19 → the semiconductor switching element Q2 as shown in FIG.
20A, the current I Q2 of the semiconductor switching element Q2 monotonically increases as shown in FIG. When the semiconductor switching element Q2 is turned off for a predetermined time, the current path shifts to the state shown in FIG. 19B, and the capacitor C1 is charged through the path of the diode D2 → the commercial power supply 1 → the inductive load circuit 19 → the diode D3 → the capacitor C1. . When all of the energy stored in the inductive load circuit 19 is released, the capacitor C1 is used as a power supply, and the capacitor C1 → the semiconductor switching element Q1 → the inductive load circuit 19 → the commercial power supply 1 → the capacitor C2, a path shown in FIG. The current flows in. When the semiconductor switching element Q1 is turned off for a predetermined time, the inductive load circuit 19 tries to flow a current in the same direction, so that the path shown in FIG.
A current flows through 2 → diode D4 → inductive load circuit 19) and charges the energy stored in inductive load circuit 19 to capacitor C1. When all the energy stored in the inductive load circuit 19 is released, a current flows again through the path of FIG. 19A, and the circuit operation continues. JP-A-10-27184
Although not disclosed in No. 6, in order to realize this operation, the capacitances of the capacitors C1 and C2 need to have a capacitance relationship as shown in Expression 1.
【０００９】（式１） Ｃ１≫Ｃ２ このような関係を満たすためにコンデンサＣ１には電解
コンデンサのような大容量に対応できるコンデンサを用
いる必要がある。(Equation 1) C1≫C2 In order to satisfy such a relationship, it is necessary to use a capacitor capable of handling a large capacity such as an electrolytic capacitor as the capacitor C1.
【００１０】このような動作によって商用電源１からの
電流を電源周期の略全域に渡り流すことができるように
なり入力電流の力率向上、高調波の抑制と回路の簡素化
を図っている。Such an operation allows the current from the commercial power supply 1 to flow over substantially the entire power supply cycle, thereby improving the power factor of the input current, suppressing harmonics, and simplifying the circuit.
【００１１】[0011]
【発明が解決しようとする課題】しかしながら、前記従
来の構成では下記にあげるような課題がある。However, the conventional structure has the following problems.
【００１２】すなわち、商用電源の電圧が変動した場合
にマグネトロンが発振可能な状態に移行しているにもか
かわらずマグネトロンの発振を検出できず所定の高周波
出力を出すことができない。或いは、マグネトロンが発
振可能な状態になっていないにもかかわらず発振したと
判定し高圧回路に過電圧を生じ、高圧回路の部品に過度
の電圧責務を与えてしまう可能性がある。That is, when the voltage of the commercial power supply fluctuates, the magnetron cannot detect the oscillation and cannot output a predetermined high-frequency output even though the magnetron has shifted to the oscillating state. Alternatively, there is a possibility that it is determined that the magnetron has oscillated even though the magnetron is not in an oscillating state, and an overvoltage is generated in the high-voltage circuit, thereby giving an excessive voltage duty to components of the high-voltage circuit.
【００１３】本発明はこのような課題に鑑みてなしたも
のであり、商用電源の電圧が変動しても確実にマグネト
ロンの発振を判定することができるマグネトロン駆動用
電源を提供することを目的としている。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a magnetron drive power supply that can reliably determine magnetron oscillation even when the voltage of a commercial power supply fluctuates. I have.
【００１４】[0014]
【課題を解決するための手段】前記従来の課題を解決す
るために、本発明のマグネトロン駆動用電源は第１およ
び第２の逆導通可能な半導体スイッチ素子の直列接続体
と、第１および第２のダイオードの直列接続体を並列接
続し、前記第１および第２のダイオードに各々並列に第
１と第２のコンデンサを接続し、前記第１および第２の
逆導通可能な半導体スイッチ素子の接続点と、前記第１
および第２のダイオードの接続点間に商用電源と高圧ト
ランスの１次巻線の直列回路を接続し、前記高圧トラン
スの２次巻線の出力は高圧整流回路を介してマグネトロ
ンを付勢し、前記第１および第２の半導体スイッチ素子
を駆動する駆動回路を有し、前記駆動回路は前記第１お
よび第２の半導体スイッチ素子を相補的に駆動するとと
もに前記駆動回路は前記マグネトロンの発振を検知する
発振検知部を有し、前記発振検知部は商用電源の電圧に
応じて前記マグネトロンの発振を判定する基準値を変化
させる構成としたものである。In order to solve the above-mentioned conventional problems, a magnetron driving power supply according to the present invention comprises a series connection of first and second reverse-conductive semiconductor switch elements, A first and a second capacitor connected in parallel to the first and second diodes, respectively, and a first and a second reverse-conductive semiconductor switch element. The connection point and the first
A series circuit of a commercial power supply and a primary winding of a high-voltage transformer is connected between the connection points of the second diode and the second diode, and an output of the secondary winding of the high-voltage transformer energizes the magnetron through a high-voltage rectifier circuit; A driving circuit for driving the first and second semiconductor switching elements, the driving circuit driving the first and second semiconductor switching elements complementarily, and the driving circuit detecting oscillation of the magnetron An oscillation detection unit that changes a reference value for judging the oscillation of the magnetron according to a voltage of a commercial power supply.
【００１５】これによって、商用電源の電圧が変動して
もマグネトロンの発振を確実に判定することができる。This makes it possible to reliably determine the oscillation of the magnetron even if the voltage of the commercial power supply fluctuates.
【００１６】[0016]
【発明の実施の形態】請求項１に記載の発明は、第１お
よび第２の逆導通可能な半導体スイッチ素子の直列接続
体と、第１および第２のダイオードの直列接続体を並列
接続し、前記第１および第２のダイオードに各々並列に
第１と第２のコンデンサを接続し、前記第１および第２
の逆導通可能な半導体スイッチ素子の接続点と、前記第
１および第２のダイオードの接続点間に商用電源と高圧
トランスの１次巻線の直列回路を接続し、前記高圧トラ
ンスの２次巻線の出力は高圧整流回路を介してマグネト
ロンを付勢し、前記第１および第２の半導体スイッチ素
子を駆動する駆動回路を有し、前記駆動回路は前記第１
および第２の半導体スイッチ素子を相補的に駆動すると
ともに前記駆動回路は前記マグネトロンの発振を検知す
る発振検知部を有し、前記発振検知部は商用電源の電圧
に応じて前記マグネトロンの発振を判定する基準値を変
化させる構成とすることにより、マグネトロンの発振判
定基準値が商用電源の電圧変動に対して適切な値に設定
されるので、電源電圧が変動しても確実にマグネトロン
の発振判定ができ、マグネトロン駆動用電源の高圧回路
に過大な電圧責務を印加することを防止することができ
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a series connection of first and second reverse-conducting semiconductor switch elements and a series connection of first and second diodes are connected in parallel. , First and second capacitors are connected in parallel to the first and second diodes, respectively, and the first and second capacitors are connected.
A series circuit of a commercial power supply and a primary winding of a high-voltage transformer is connected between a connection point of a semiconductor switch element capable of reverse conduction and a connection point of the first and second diodes. The output of the line includes a drive circuit for energizing a magnetron via a high voltage rectifier circuit to drive the first and second semiconductor switch elements, wherein the drive circuit comprises the first
And a drive circuit for driving the second semiconductor switch element in a complementary manner, the drive circuit having an oscillation detection unit for detecting the oscillation of the magnetron, wherein the oscillation detection unit determines the oscillation of the magnetron according to the voltage of the commercial power supply. In this configuration, the magnetron oscillation judgment reference value is set to an appropriate value with respect to the voltage fluctuation of the commercial power supply, so that the magnetron oscillation judgment can be reliably performed even if the power supply voltage fluctuates. As a result, it is possible to prevent an excessive voltage duty from being applied to the high-voltage circuit of the power supply for driving the magnetron.
【００１７】請求項２に記載の発明は、特に、請求項１
に記載の発振検知部がマグネトロンの発振を判定する基
準値は商用電源が定格電圧の時に極大となり前記商用電
源の電圧が定格電圧に対して増減した場合は基準値を減
ずる構成とすることによって、マグネトロンの発振判定
基準値が商用電源の電圧変動に対して適切な値に設定さ
れるので、電源電圧が変動しても確実にマグネトロンの
発振判定ができ、マグネトロン駆動用電源の高圧回路に
過大な電圧責務を印加することを防止することができ
る。The invention described in claim 2 is particularly advantageous in claim 1.
The reference value for determining the oscillation of the magnetron by the oscillation detection unit described in the above is a maximum when the commercial power supply is at the rated voltage, and by reducing the reference value when the voltage of the commercial power supply is increased or decreased with respect to the rated voltage, Since the magnetron oscillation judgment reference value is set to an appropriate value for the voltage fluctuation of the commercial power supply, even if the power supply voltage fluctuates, the magnetron oscillation judgment can be made reliably, and the high voltage circuit of the magnetron drive power supply is excessively large. Applying a voltage duty can be prevented.
【００１８】請求項３に記載の発明は、特に、請求項２
に記載の発振検知部がマグネトロンの発振を判定する基
準値に下限値を設定する構成とすることにより、過度に
低い電源電圧や過度に高い電源電圧に対しては発振判定
をしなくなるので、異常な電源電圧に対してマグネトロ
ン駆動用電源が大電力で動作することを防止でき、イン
バータ回路に過度な電圧および電流責務が印加すること
を防止することができる。The invention described in claim 3 is particularly advantageous in claim 2
By setting the lower limit to the reference value for judging the oscillation of the magnetron by the oscillation detector described in the above, oscillation judgment will not be performed for an excessively low power supply voltage or an excessively high power supply voltage. It is possible to prevent the magnetron driving power supply from operating at a large power with respect to a suitable power supply voltage, and prevent an excessive voltage and current duty from being applied to the inverter circuit.
【００１９】請求項４に記載の発明は、特に、請求項１
から３のいずれか１項に記載のマグネトロン駆動用電源
に商用電源の電圧を検出する電源電圧検知部を設け、発
振検知部は前記電源電圧検知部の出力信号に応じてマグ
ネトロンの発振を判定する基準値を変化させる構成とす
ることにより、マグネトロンの発振判定基準値が商用電
源の電圧変動に対して適切な値に設定されるので、電源
電圧が変動しても確実にマグネトロンの発振判定がで
き、マグネトロン駆動用電源の高圧回路に過大な電圧責
務を印加することを防止することができる。The invention described in claim 4 is particularly advantageous in claim 1.
The power supply for driving a magnetron according to any one of the above items, further comprising a power supply voltage detection unit for detecting a voltage of a commercial power supply, wherein the oscillation detection unit determines the oscillation of the magnetron according to an output signal of the power supply voltage detection unit. By changing the reference value, the magnetron oscillation judgment reference value is set to an appropriate value with respect to the voltage fluctuation of the commercial power supply, so that the magnetron oscillation judgment can be made reliably even if the power supply voltage fluctuates. In addition, it is possible to prevent an excessive voltage duty from being applied to the high voltage circuit of the power supply for driving the magnetron.
【００２０】請求項５に記載の発明は、特に、請求項４
に記載の電源電圧検知部を第１および第２のコンデンサ
の直列接続体の電圧を検出するよう構成することによ
り、マグネトロン駆動用電源が停止時に商用電源の電圧
に応じた電圧を検出することができ、マグネトロンの発
振判定基準値が商用電源の電圧変動に対して適切な値に
設定されるので、電源電圧が変動しても確実にマグネト
ロンの発振判定ができ、マグネトロン駆動用電源の高圧
回路に過大な電圧責務を印加することを防止することが
できる。The invention described in claim 5 is particularly advantageous in claim 4.
By configuring the power supply voltage detection unit described in (1) to detect the voltage of the series-connected body of the first and second capacitors, it is possible to detect the voltage corresponding to the voltage of the commercial power supply when the power supply for driving the magnetron is stopped. The magnetron oscillation judgment reference value is set to an appropriate value for the voltage fluctuation of the commercial power supply, so even if the power supply voltage fluctuates, the magnetron oscillation judgment can be made reliably, and the magnetron drive power supply high-voltage circuit can be used. Applying an excessive voltage duty can be prevented.
【００２１】請求項６に記載の発明は、特に、請求項４
に記載の電源電圧検知部を商用電源と昇圧トランスの接
続点の電圧を検出する構成とすることにより、マグネト
ロンの発振判定基準値が商用電源の電圧変動に対して適
切な値に設定されるので、電源電圧が変動しても確実に
マグネトロンの発振判定ができ、マグネトロン駆動用電
源の高圧回路に過大な電圧責務を印加することを防止す
ることができる。The invention described in claim 6 is particularly preferable in claim 4
Since the power supply voltage detection unit described in (1) detects the voltage at the connection point between the commercial power supply and the step-up transformer, the oscillation determination reference value of the magnetron is set to an appropriate value with respect to the voltage fluctuation of the commercial power supply. Even if the power supply voltage fluctuates, the oscillation of the magnetron can be reliably determined, and it is possible to prevent applying an excessive voltage duty to the high voltage circuit of the power supply for driving the magnetron.
【００２２】請求項７に記載の発明は、特に、請求項６
に記載の電源電圧検知部の働きを商用電源の極性を判定
する極性判定手段を設け、商用電源の極性が正極あるい
は負極いずれか一方の極性のときのみ電源電圧検知部は
商用電源の電圧を検出する構成とすることにより、マグ
ネトロンの発振判定基準値が商用電源の電圧変動に対し
て適切な値に設定されるので、電源電圧が変動しても確
実にマグネトロンの発振判定ができ、マグネトロン駆動
用電源の高圧回路に過大な電圧責務を印加することを防
止することができる。The invention described in claim 7 is particularly advantageous in claim 6
The power supply voltage detector detects the polarity of the commercial power supply, and the power supply voltage detector detects the voltage of the commercial power supply only when the polarity of the commercial power supply is either the positive polarity or the negative polarity. With this configuration, the magnetron oscillation judgment reference value is set to an appropriate value with respect to the voltage fluctuation of the commercial power supply, so that the magnetron oscillation judgment can be made reliably even if the power supply voltage fluctuates, It is possible to prevent an excessive voltage duty from being applied to the high voltage circuit of the power supply.
【００２３】請求項８に記載の発明は、特に、請求項１
から７のいずれか１項に記載のマグネトロン駆動用電源
に計時手段を設け所定時間以内にマグネトロンの発振を
検出できない場合は再起動する構成とすることにより、
高圧回路に継続的に高電圧が印加し続けることをなくす
ことができる。The invention described in claim 8 is particularly advantageous in claim 1.
7. The magnetron driving power supply according to any one of the items 7 to 7 is provided with a time-measuring means, and when the oscillation of the magnetron cannot be detected within a predetermined time, the magnetron is restarted.
It is possible to prevent continuous application of a high voltage to the high voltage circuit.
【００２４】請求項９に記載の発明は、特に、請求項８
のマグネトロン駆動用電源に計数手段を設けマグネトロ
ン駆動用電源が再起動を所定回数以上繰り返そうとした
場合は動作を停止する構成とすることにより、再起動が
所定回数以下に制限されるので、マグネトロンの異常や
電源電圧の異常を検出することができ、マグネトロン駆
動用電源に異常に高い電圧や大電流が印加することを防
止することができる。The invention described in claim 9 is particularly advantageous in claim 8
The magnetron driving power supply is provided with a counting means, and when the magnetron driving power supply tries to repeat the restart more than a predetermined number of times, the operation is stopped, so that the restart is limited to a predetermined number of times or less. It is possible to detect abnormalities and abnormalities in the power supply voltage, and to prevent an abnormally high voltage or large current from being applied to the magnetron driving power supply.
【００２５】[0025]
【実施例】以下、本発明の実施例について、図面を参照
しながら説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００２６】（実施例１）本発明の第１の実施例につい
て図１から図５を用いて説明する。図１は本発明のマグ
ネトロン駆動用電源の第１の実施例を示す回路図であ
る。第１、第２の半導体スイッチ素子２０、２１の直列
接続体と第１、第２のダイオード２２、２３の直列接続
体を並列接続し、第１、第２のダイオード２２、２３に
各々並列に第１、第２のコンデンサ２４、２５を接続す
るとともに半導体スイッチ素子２０、２１の接続点とダ
イオード２２、２３の接続点間に商用電源１と高圧トラ
ンス２６の直列回路を接続する構成となっている。高圧
トランス２６の２次巻線出力は高圧整流回路７に接続さ
れマグネトロン８に直流高電圧を印加する。マグネトロ
ン８はこの直流高電圧によって付勢され２．４５GHzの
電波を発生する。なお本実施例では第１、第２の半導体
スイッチ素子は順方向に導通するＩＧＢＴ（絶縁ゲート
バイポーラトランジスタ）とこれと逆並列に接続したダ
イオードにて記載しているが、ＭＯＳＦＥＴのように素
子内部にダイオードを構成したような素子を用いても適
用可能であることは言うまでもない。駆動回路２７は第
１の半導体スイッチング素子２０、および第２の半導体
スイッチング素子２１を所定のデッドタイムを持って相
補的に駆動するように其々の半導体スイッチング素子に
駆動信号を与える。(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram showing a first embodiment of a magnetron driving power supply according to the present invention. A series connection of the first and second semiconductor switch elements 20 and 21 and a series connection of the first and second diodes 22 and 23 are connected in parallel, and are connected in parallel to the first and second diodes 22 and 23, respectively. The first and second capacitors 24 and 25 are connected, and the series circuit of the commercial power supply 1 and the high-voltage transformer 26 is connected between the connection point of the semiconductor switch elements 20 and 21 and the connection point of the diodes 22 and 23. I have. The secondary winding output of the high voltage transformer 26 is connected to the high voltage rectifier circuit 7 and applies a high DC voltage to the magnetron 8. The magnetron 8 is energized by the high DC voltage and generates a radio wave of 2.45 GHz. In the present embodiment, the first and second semiconductor switch elements are described as IGBTs (insulated gate bipolar transistors) that conduct in the forward direction and diodes connected in anti-parallel to the IGBTs. It is needless to say that the present invention can be applied even if an element such as a diode is used. The drive circuit 27 supplies a drive signal to each of the first semiconductor switching element 20 and the second semiconductor switching element 21 so as to drive them complementarily with a predetermined dead time.
【００２７】図２はインバータ回路の各期間における電
流が流れる経路を示した図であり、図３はそれに対応し
た動作波形図である。商用電源１の極性が図示の状態で
半導体スイッチ素子２１がオンの状態から説明をはじめ
る。この状態では図２（ａ）に示すように商用電源１→
高圧トランス２６の1次巻線→半導体スイッチ素子２１
→ダイオード２３の経路で電流が流れ、図３（ａ）の期
間のＩ２１に示す電流が半導体スイッチ素子２１および
高圧トランス２６の１次巻線に電流が流れることによっ
て高圧トランス２６の１次巻線にエネルギーを蓄積す
る。半導体スイッチ素子２１を所定の時間でオフすると
高圧トランス２６の１次巻線電流は同じ方向に流れ続け
ようとするので今度は図２（ｂ）に示すごとく商用電源
１→高圧トランス２６の１次巻線→半導体スイッチ素子
２０の並列ダイオード→コンデンサ２４の経路で高圧ト
ランス２６の１次巻線に蓄えたエネルギーをコンデンサ
２４に充電する。この動作によってコンデンサ２４には
商用電源１の電圧を昇圧した電圧が蓄えられる。高圧ト
ランス２６の１次巻線に蓄えたエネルギーをすべて放出
すると図２（ｃ）の経路が形成され今度はコンデンサ２
４に充電したエネルギーをコンデンサ２４→半導体スイ
ッチ素子２０→高圧トランス２６の１次巻線→商用電源
１の経路で取り出す。そして半導体スイッチ素子２０を
所定の時間でオフすると高圧トランス２６の１次巻線は
同じ方向に電流を流し続けようとするので図２（ｄ）の
ように高圧トランス２６の１次巻線→商用電源１→コン
デンサ２５→半導体スイッチ素子２１の並列ダイオード
の経路で電流が流れる。商用電源１の電圧極性が図示と
逆極性の場合は半導体スイッチ素子２０、２１とダイオ
ード２２、２３とコンデンサ２４、２５の動作がそれぞ
れ入れ替わるだけで同様の動作をする。FIG. 2 is a diagram showing a path through which a current flows in each period of the inverter circuit, and FIG. 3 is an operation waveform diagram corresponding thereto. The description starts from a state where the polarity of the commercial power supply 1 is shown and the semiconductor switch element 21 is on. In this state, as shown in FIG.
Primary winding of high-voltage transformer 26 → semiconductor switch element 21
→ A current flows through the path of the diode 23, and the current indicated by I21 in the period of FIG. 3A flows through the semiconductor switch element 21 and the primary winding of the high-voltage transformer 26. To store energy. When the semiconductor switch element 21 is turned off for a predetermined time, the primary winding current of the high voltage transformer 26 tends to continue to flow in the same direction. Therefore, as shown in FIG. The energy stored in the primary winding of the high-voltage transformer 26 is charged in the capacitor 24 through the path of the winding → the parallel diode of the semiconductor switch element 20 → the capacitor 24. By this operation, a voltage obtained by boosting the voltage of the commercial power supply 1 is stored in the capacitor 24. When all the energy stored in the primary winding of the high-voltage transformer 26 is released, the path shown in FIG.
The energy charged in 4 is taken out through the path of the capacitor 24 → the semiconductor switch element 20 → the primary winding of the high voltage transformer 26 → the commercial power supply 1. When the semiconductor switch element 20 is turned off for a predetermined time, the primary winding of the high-voltage transformer 26 tries to keep the current flowing in the same direction, so that the primary winding of the high-voltage transformer 26 → commercial as shown in FIG. A current flows through a path from the power supply 1 → the capacitor 25 → the parallel diode of the semiconductor switch element 21. When the voltage polarity of the commercial power supply 1 is opposite to that shown in the figure, the same operation is performed except that the operations of the semiconductor switch elements 20 and 21, the diodes 22 and 23, and the capacitors 24 and 25 are switched.
【００２８】上記の動作においてコンデンサ２４、２５
は半導体スイッチ素子２０、２１のオンオフによって高
圧トランス２６の１次巻線に高周波電流を発生させるイ
ンバータ動作と商用電源１の電圧に対して昇圧した電圧
をコンデンサ２４、２５に発生させる動作を兼用できる
ような容量に設計され、コンデンサ２４、２５の容量は
相等しい容量で構成されている。この結果商用電源１の
電圧極性が図示の場合はコンデンサ２４に商用電源１の
電圧を昇圧した電圧を蓄え、反対に商用電源１の電圧極
性が図示とは逆極性の場合はコンデンサ２５に商用電源
１の電圧を昇圧した電圧を蓄える動作をする。したがっ
て商用電源１の電圧極性によらずコンデンサ２４、２５
に発生する電圧を等しくすることができるので商用電源
１の電流は正負対称な波形とすることができる。そし
て、このような動作を継続することで図４に示すように
商用電源１の周期に対してコンデンサ２４、２５の電圧
波形は商用電源１の電圧極性に応じて昇圧した電圧を発
生する。このため高圧トランス２６の１次巻線に流れる
電流の包絡線波形はＶ２６（Ｌｐ）に示すような波形と
なる。この電圧を高圧トランス２６は昇圧してマグネト
ロン８に印加するのでマグネトロン８に印加する電圧は
Ｖ８のような波形を示し、常に発振電圧VAK(TH )以上の
電圧を維持することが可能となる。この結果入力電流Ｉ
１は商用電源１のいずれの期間においても電流を流すこ
とができ、力率の改善、高調波の抑制を実現することが
できる。In the above operation, the capacitors 24, 25
Can perform both an inverter operation for generating a high-frequency current in the primary winding of the high-voltage transformer 26 by turning on and off the semiconductor switch elements 20 and 21 and an operation for generating voltages boosted with respect to the voltage of the commercial power supply 1 in the capacitors 24 and 25. The capacitors are designed to have such a capacity, and the capacitors 24 and 25 have the same capacity. As a result, when the voltage polarity of the commercial power supply 1 is shown in the figure, the boosted voltage of the commercial power supply 1 is stored in the capacitor 24, and when the voltage polarity of the commercial power supply 1 is opposite to that shown in the figure, the capacitor 25 is connected to the capacitor 25. An operation of storing a voltage obtained by boosting the voltage of 1 is performed. Therefore, regardless of the voltage polarity of the commercial power supply 1, the capacitors 24, 25
Can be made equal, the current of the commercial power supply 1 can have a positive and negative symmetric waveform. By continuing such an operation, the voltage waveform of the capacitors 24 and 25 with respect to the cycle of the commercial power supply 1 generates a voltage boosted according to the voltage polarity of the commercial power supply 1 as shown in FIG. Therefore, the envelope waveform of the current flowing through the primary winding of the high-voltage transformer 26 becomes a waveform as indicated by V26 (Lp). Since this voltage is boosted by the high-voltage transformer 26 and applied to the magnetron 8, the voltage applied to the magnetron 8 has a waveform like V8, and it is possible to always maintain a voltage higher than the oscillation voltage VAK (TH ) . As a result, the input current I
1 allows a current to flow in any period of the commercial power supply 1, and can improve the power factor and suppress harmonics.
【００２９】また、図３において期間（ａ）から（ｂ）
へ移行する際ダイオード２３をカットオフする動作にな
るが電流経路として半導体スイッチ素子２１が直列に接
続されているので電流の遮断は半導体スイッチ素子２１
が行うことになりダイオード２３のスイッチングスピー
ドは要求されない。また、オフ時にダイオード２３に印
加する電圧は零であるのでターンオフ時のスイッチング
損失はまったく生じない。したがってダイオード２２、
２３の設計としては順方向オン電圧ＶＦを重視した設計
で導通時の損失を重点的に抑制するように設計すること
が可能となり、ダイオード２２、２３の小形化と同時に
ダイオード２２、２３を冷却する構成の簡素化を図るこ
とが容易となる。特に電子レンジで用いるようなマグネ
トロン駆動用電源は１０００Ｗ以上の高電力を扱うので
インバータ回路の電流は４０Ａから５０Ａ程度の非常に
大きな電流レベルとなりダイオード２２、２３の設計を
順方向オン電圧ＶＦを重視して導通損失を低減すること
はインバータ回路の効率向上に有益である。このためイ
ンバータ回路のトータルの電力損失をきわめて低く抑え
ることができ、効率の高いマグネトロン駆動用電源を実
現することができる。In FIG. 3, periods (a) to (b)
When the operation is shifted to the operation mode, the operation of cutting off the diode 23 is performed.
Therefore, the switching speed of the diode 23 is not required. Further, since the voltage applied to the diode 23 at the time of turning off is zero, no switching loss occurs at the time of turning off. Therefore, the diode 22,
As for the design of the diode 23, it is possible to design to emphasize the forward ON voltage VF and to mainly suppress the loss at the time of conduction, and to cool down the diodes 22 and 23 at the same time as the diodes 22 and 23 are downsized. It is easy to simplify the configuration. In particular, the power supply for driving a magnetron used in a microwave oven handles a high power of 1000 W or more, so that the current of the inverter circuit becomes a very large current level of about 40 A to 50 A. Reducing the conduction loss by doing so is beneficial for improving the efficiency of the inverter circuit. For this reason, the total power loss of the inverter circuit can be suppressed extremely low, and a highly efficient magnetron drive power supply can be realized.
【００３０】このように本実施例のマグネトロン駆動用
電源においては従来例で示した回路とは全く異なった回
路動作によってダイオード２２、２３の設計を順方向オ
ン電圧ＶＦ重視の設計とすることが可能となりダイオー
ド２２、２３の損失を極小化しマグネトロン駆動用電源
全体の電力変換効率を向上している。この効果はコンデ
ンサ２４、２５がインバータ動作とコンデンサ２４、２
５に商用電源１の電圧を昇圧した電圧を加える動作を兼
用することによって発揮される本発明における特有の効
果であり、従来例にて挙げた特開平１０−２７１８４６
の構成とは異なったコンデンサの回路機能と回路動作に
よって実現されるものである。As described above, in the magnetron driving power supply of the present embodiment, the design of the diodes 22 and 23 can be designed to emphasize the forward ON voltage VF by a completely different circuit operation from the circuit shown in the conventional example. The loss of the diodes 22 and 23 is minimized, and the power conversion efficiency of the entire magnetron driving power supply is improved. The effect is that the capacitors 24 and 25 operate in inverter operation and
5 is a unique effect of the present invention exhibited by also using the operation of adding the voltage of the commercial power supply 1 to the voltage of the commercial power supply 1.
Is realized by a circuit function and a circuit operation of a capacitor different from the configuration of FIG.
【００３１】図４は本実施例のマグネトロン駆動用電源
において動作開始からマグネトロンが発振可能となるま
での期間におけるマグネトロンにかかる電圧Ｖａｋおよ
びマグネトロンのカソードの温度の時間変化を示した図
である。マグネトロンのカソードは昇圧トランスに設け
られたヒータ巻線から電力供給を受けて、温度上昇しカ
ソードから熱電子を安定に放出できる温度まで上昇す
る。一般にこの温度は１９００Ｋから２１００Ｋ程度で
あり、ヒータ巻線はこの温度に相当した電力をカソード
に供給するように設計されている。図５は商用電源の電
圧が変動した場合において昇圧トランスの１次巻線の発
生電圧を一定とした場合でのマグネトロンが非発振の期
間と発振可能な状態になった時の入力電流の差異を示し
た図である。この図を見てわかるように商用電源の電圧
が定格電圧付近ではマグネトロンが非発振の状態と発振
可能な状態とで入力電流の差が大きく発振を検出する基
準値の設定は比較的容易に設定することができる。しか
しながら、定格電圧から外れた電圧においてはこの入力
電流の差があまりない。従って、商用電源の電圧によら
ず一定の入力電流でマグネトロンの発振を検出するよう
に構成すると定格電圧から外れた電圧ではマグネトロン
が発振できる状態まで遷移していないにもかかわらず発
振したと判定したり、マグネトロンはすでに発振可能な
状態に遷移しているにもかかわらず発振していないと判
定するケースが発生する。しかしながら、本発明におい
てはマグネトロンが発振したと判定する基準値を商用電
源の電圧に応じて変化させ、其々の電圧において適切な
基準値となるようにしているので商用電源の電圧が変動
しても確実にマグネトロンが発振状態に遷移したか否か
を判定することが可能となる。FIG. 4 is a diagram showing the time variation of the voltage Vak applied to the magnetron and the temperature of the cathode of the magnetron during the period from the start of operation to the time when the magnetron can oscillate in the magnetron driving power supply of this embodiment. The cathode of the magnetron receives power supply from a heater winding provided in the step-up transformer, and the temperature rises to a temperature at which thermoelectrons can be stably emitted from the cathode. Generally, this temperature is about 1900K to 2100K, and the heater winding is designed to supply electric power corresponding to this temperature to the cathode. FIG. 5 shows the difference between the input current when the magnetron is not oscillating and the input current when the oscillating state is obtained when the voltage of the primary winding of the step-up transformer is constant when the voltage of the commercial power supply fluctuates. FIG. As can be seen from this figure, when the voltage of the commercial power supply is near the rated voltage, the difference in input current between the non-oscillating state and the oscillating state of the magnetron is large, and the reference value for detecting oscillation is relatively easy to set. can do. However, there is not much difference between the input currents at voltages outside the rated voltage. Therefore, if the configuration is such that the magnetron oscillation is detected at a constant input current regardless of the voltage of the commercial power supply, it is determined that the magnetron has oscillated at a voltage outside the rated voltage even though the magnetron has not transitioned to a state where it can oscillate. In some cases, it is determined that the magnetron is not oscillating even though the magnetron has already transited to an oscillating state. However, in the present invention, the reference value for determining that the magnetron oscillates is changed in accordance with the voltage of the commercial power supply, so that the appropriate reference value is obtained at each voltage, so that the voltage of the commercial power supply fluctuates. Also, it is possible to reliably determine whether the magnetron has transitioned to the oscillation state.
【００３２】（実施例２）本発明の第２の実施例につい
て図６から図８を用いて説明する。図６は本実施例の回
路図を示す図である。前述の実施例１と同一符号の構成
要素は同一の作用を持つものであり、ここではその動作
の詳細については省略する。２９は電源電圧検知部であ
り、第１および第２のコンデンサの直列接続体の出力電
圧を検出するように構成されている。電源電圧検知部２
９はこの検出電圧に基づいて発振検知部２８に信号を送
信し、発振検知部２８は電源電圧検知部２９からの信号
に基づいてマグネトロン８が発振したか否かを判定する
基準値を変化させるように働く。ここで、商用電源１の
電圧と第１および第２のコンデンサの直列接続体の出力
電圧は図７に示すように、マグネトロン駆動用電源が停
止しているときは必ずＶ２＝２×Ｖ１Ｖ１：商用電源の
電圧の最大値Ｖ２：第１および第２のコンデンサの直列
接続体の出力電圧なる関係となっている。これは第１お
よび第２の半導体スイッチ素子２０、２１がオフ状態で
インバータ回路が停止している状態では第１および第２
のコンデンサ２４、２５と第１および第２の半導体スイ
ッチ素子２０、２１に逆並列に接続されたダイオード２
２、２３によって商用電源１の電圧を倍電圧整流する構
成となるからである。従って、第１および第２のコンデ
ンサ２４、２５の直列接続体の出力電圧を検出すること
によって商用電源の電圧変動を忠実に検出することが可
能となる。そして、発振検知部２８は電源電圧検知部２
９の検知電圧に応じてマグネトロン８が発振したと判定
する基準値を図８のように変化させる。この結果、其々
の電圧において適切な基準値となるようにしているので
商用電源１の電圧が変動しても確実にマグネトロン８が
発振状態に遷移したか否かを判定することが可能とな
る。(Embodiment 2) A second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a diagram showing a circuit diagram of the present embodiment. The components having the same reference numerals as those in the first embodiment have the same function, and the details of the operation are omitted here. Reference numeral 29 denotes a power supply voltage detection unit, which is configured to detect an output voltage of a series connection of the first and second capacitors. Power supply voltage detector 2
9 transmits a signal to the oscillation detection unit 28 based on the detected voltage, and the oscillation detection unit 28 changes a reference value for determining whether or not the magnetron 8 has oscillated based on a signal from the power supply voltage detection unit 29. Work like that. Here, as shown in FIG. 7, the voltage of the commercial power supply 1 and the output voltage of the series connection of the first and second capacitors are always V2 = 2 × V1V1: commercial power when the power supply for driving the magnetron is stopped. The relationship is the maximum value V2 of the voltage of the power supply: the output voltage of the series connection of the first and second capacitors. This is because when the first and second semiconductor switch elements 20 and 21 are off and the inverter circuit is stopped, the first and second semiconductor switch elements 20 and 21 are turned off.
Diode 2 connected in anti-parallel to capacitors 24 and 25 and first and second semiconductor switch elements 20 and 21
This is because the voltage of the commercial power supply 1 is double-voltage rectified by 2 and 23. Therefore, by detecting the output voltage of the series connection of the first and second capacitors 24 and 25, it is possible to faithfully detect the voltage fluctuation of the commercial power supply. The oscillation detection unit 28 is connected to the power supply voltage detection unit 2.
The reference value for determining that the magnetron 8 has oscillated according to the detected voltage 9 is changed as shown in FIG. As a result, an appropriate reference value is set for each voltage, so that it is possible to reliably determine whether the magnetron 8 has transitioned to the oscillation state even if the voltage of the commercial power supply 1 fluctuates. .
【００３３】（実施例３）本発明の第３の実施例につい
て図９から１１を用いて説明する。図９は本実施例のマ
グネトロン駆動用電源の回路図である。前述までの実施
例１、２と同一の符号を付した構成要素は同一の作用を
有するものであり、ここではその詳細な動作の説明につ
いては割愛する。本実施例では電源電圧検知部は商用電
源と昇圧トランスの１次巻線の接続部から信号を検出す
る構成となっている。この接続点の電圧は図１０に示す
ように商用電源の正極或いは負極に一方の極性の時には
商用電源と同一の電圧を出力する。本実施例では電源電
圧の極性を判定する電源極性判定手段をも有しており、
電源電圧検知部は電源極性判定手段が商用電源の極性を
正極であると判定している期間のみ電圧を検出し、商用
電源の電圧を測定するよう構成されている。また、発振
検知部は電源電圧検知部の検知電圧に応じてマグネトロ
ンが発振したと判定する基準値を図１１のように変化さ
せる。この結果、其々の電圧において適切な基準値とな
るようにしているので商用電源の電圧が変動しても確実
にマグネトロンが発振状態に遷移したか否かを判定する
ことが可能となる。(Embodiment 3) A third embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a circuit diagram of the magnetron driving power supply of the present embodiment. The components denoted by the same reference numerals as those in the first and second embodiments have the same operation, and the detailed description of the operation is omitted here. In the present embodiment, the power supply voltage detection unit is configured to detect a signal from a connection between the commercial power supply and the primary winding of the step-up transformer. As shown in FIG. 10, the voltage at this connection point outputs the same voltage as that of the commercial power supply when the polarity is one of the positive and negative electrodes of the commercial power supply. This embodiment also has a power supply polarity determination unit that determines the polarity of the power supply voltage,
The power supply voltage detection unit is configured to detect the voltage only during a period when the power supply polarity determining unit determines that the polarity of the commercial power supply is positive, and measure the voltage of the commercial power supply. The oscillation detector changes the reference value for determining that the magnetron has oscillated according to the detection voltage of the power supply voltage detector as shown in FIG. As a result, the respective reference voltages are set to appropriate reference values. Therefore, even if the voltage of the commercial power supply fluctuates, it is possible to reliably determine whether the magnetron has transitioned to the oscillation state.
【００３４】（実施例４）本発明の第４の実施例につい
て図１２を用いて説明する。図１２は本実施例のマグネ
トロン駆動用電源の回路図である。前述までの実施例
１、２および３と同一の符号を付した構成要素は同一の
作用を有するものでありここでは詳細な説明は割愛す
る。ここで３１は計時手段であり、インバータ回路が動
作を開始し、半導体スイッチ素子にゲート信号が発生し
始めてからの時間を計測する。インバータ回路が動作し
始めてから一定時間を過ぎても発振検知部からマグネト
ロンの発振を判定したという信号が送られてこないとイ
ンバータ回路を一旦停止させ、所定の時間遅延して再起
動させるように機能する。また、計数手段３２は計時手
段３１が再起動を指令した回数をカウントし、一定回数
以上再起動した場合はインバータ回路を停止させて再起
動が過からないように計数手段３２は作用する。この結
果、電源電圧が定格電圧に対して異常に高い場合や低い
場合にマグネトロンの発振を検出できなくても高圧回路
に継続的に高電圧が印加することを防止することができ
る。(Embodiment 4) A fourth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a circuit diagram of the magnetron driving power supply of the present embodiment. The components denoted by the same reference numerals as those in the first, second, and third embodiments have the same operation, and the detailed description is omitted here. Here, reference numeral 31 denotes time measuring means for measuring the time from when the inverter circuit starts operating and when the gate signal starts to be generated in the semiconductor switch element. If a signal indicating that magnetron oscillation has been determined is not sent from the oscillation detector even after a certain period of time after the inverter circuit has started operating, the inverter circuit is temporarily stopped and restarted after a predetermined delay. I do. Further, the counting means 32 counts the number of times the timer means 31 instructs the restart, and when the restart is performed more than a certain number of times, the counting means 32 operates so as to stop the inverter circuit and prevent the restart. As a result, when the power supply voltage is abnormally high or low with respect to the rated voltage, it is possible to prevent the high voltage from being continuously applied to the high voltage circuit even if the magnetron oscillation cannot be detected.
【００３５】[0035]
【発明の効果】以上のように、本発明によれば、マグネ
トロンのような非線形な特性をもつ負荷であっても商用
電源の略全域にわたり入力電流を流すことができるとと
もに電子レンジのような高い変換電力を扱う機器におい
てもインバータ回路の発生損失を抑制することができ高
効率のマグネトロン駆動用電源を実現することができる
とともに、商用電源の電圧が変動してもマグネトロンが
発振状態に遷移したか否かを確実に判定することがで
き、特に高圧回路に過度な高電圧を継続的に印加するこ
とを防止することができる。As described above, according to the present invention, even with a load having a non-linear characteristic such as a magnetron, an input current can flow over substantially the entire area of a commercial power supply and a high load such as a microwave oven can be obtained. Even in equipment that handles converted power, it is possible to suppress the generation loss of the inverter circuit and realize a high-efficiency power supply for driving the magnetron, and to determine whether the magnetron transitions to the oscillation state even if the voltage of the commercial power supply fluctuates. It is possible to reliably determine whether the voltage is high or not, and it is possible to prevent continuous application of an excessively high voltage to the high-voltage circuit.
【図１】本発明の実施例１におけるマグネトロン駆動用
電源を示す回路図FIG. 1 is a circuit diagram illustrating a magnetron driving power supply according to a first embodiment of the present invention.
【図２】同マグネトロン駆動用電源のインバータ回路の
各期間における電流が流れる経路を示した図FIG. 2 is a diagram showing paths through which current flows in each period of the inverter circuit of the power supply for driving the magnetron.
【図３】同マグネトロン駆動用電源のインバータ回路の
動作波形図FIG. 3 is an operation waveform diagram of the inverter circuit of the power supply for driving the magnetron.
【図４】同マグネトロン駆動用電源の起動時におけるマ
グネトロンにかかる電圧Ｖａｋとカソード温度の変化を
示す図FIG. 4 is a diagram showing a change in a voltage Vak applied to the magnetron and a change in cathode temperature when the magnetron driving power supply is started.
【図５】同マグネトロン駆動用電源において商用電源の
電圧変動に対するマグネトロンが非発振状態と発振状態
での入力電流の変化を示す図FIG. 5 is a diagram showing a change in an input current in a non-oscillating state and an oscillating state of the magnetron with respect to a voltage change of a commercial power supply in the magnetron driving power supply.
【図６】本発明の実施例２におけるマグネトロン駆動用
電源を示す回路図FIG. 6 is a circuit diagram showing a magnetron driving power supply according to a second embodiment of the present invention.
【図７】同マグネトロン駆動用電源における商用電源の
電圧と第１および第２のコンデンサの直列接続体の出力
電圧の関係を示す図FIG. 7 is a diagram showing a relationship between a voltage of a commercial power supply and an output voltage of a series connection of first and second capacitors in the magnetron driving power supply.
【図８】同マグネトロン駆動用電源において商用電源の
電圧変動に対するマグネトロンが非発振状態と発振状態
での入力電流の変化を示す図FIG. 8 is a diagram showing a change in input current in a non-oscillating state and an oscillating state of the magnetron with respect to a voltage change of a commercial power supply in the magnetron driving power supply.
【図９】本発明の実施例３におけるマグネトロン駆動用
電源を示す回路図FIG. 9 is a circuit diagram showing a magnetron driving power supply according to a third embodiment of the present invention.
【図１０】同マグネトロン駆動用電源において商用電源
と電源電圧検知部の検知電圧の関係を示す図FIG. 10 is a diagram showing a relationship between a commercial power supply and a detection voltage of a power supply voltage detection unit in the magnetron driving power supply.
【図１１】同マグネトロン駆動用電源において商用電源
の電圧変動に対するマグネトロンが非発振状態と発振状
態での入力電流の変化を示す図FIG. 11 is a diagram showing a change in input current in a non-oscillating state and an oscillating state of the magnetron with respect to a voltage change of a commercial power supply in the magnetron driving power supply.
【図１２】本発明の実施例４におけるマグネトロン駆動
用電源を示す回路図FIG. 12 is a circuit diagram showing a magnetron driving power supply according to a fourth embodiment of the present invention.
【図１３】従来のマグネトロン駆動用電源を示す回路図FIG. 13 is a circuit diagram showing a conventional magnetron driving power supply.
【図１４】同マグネトロン駆動用電源の動作波形図FIG. 14 is an operation waveform diagram of the magnetron driving power supply.
【図１５】従来のマグネトロン駆動用電源におけるマグ
ネトロンの動作特性図FIG. 15 is an operating characteristic diagram of a magnetron in a conventional magnetron driving power supply.
【図１６】アクティブフィルタ回路を追加した従来のマ
グネトロン駆動用電源の回路図FIG. 16 is a circuit diagram of a conventional magnetron driving power supply to which an active filter circuit is added.
【図１７】同マグネトロン駆動用電源の動作波形図FIG. 17 is an operation waveform diagram of the magnetron driving power supply.
【図１８】特開平１０−２７１８４６号公報にて公開さ
れた電源装置の回路図FIG. 18 is a circuit diagram of a power supply device disclosed in Japanese Patent Application Laid-Open No. 10-271846.
【図１９】同電源装置の各動作モードにおける電流経路
を示す回路図FIG. 19 is a circuit diagram showing a current path in each operation mode of the power supply device.
【図２０】同電源装置の動作波形図FIG. 20 is an operation waveform diagram of the power supply device.
１ 商用電源 ７ 高圧整流回路 ８ マグネトロン ２０ 第1の半導体スイッチ素子 ２１ 第2の半導体スイッチ素子 ２２ 第1のダイオード ２３ 第2のダイオード ２４ 第1のコンデンサ ２５ 第2のコンデンサ ２６ 高圧トランス ２７ 駆動回路 ２８ 発振判定部 ２９ 電源電圧検知部 ３０ 電源極性判定手段 ３１ 計時手段 ３２ 計数手段 DESCRIPTION OF SYMBOLS 1 Commercial power supply 7 High voltage rectifier circuit 8 Magnetron 20 1st semiconductor switch element 21 2nd semiconductor switch element 22 1st diode 23 2nd diode 24 1st capacitor 25 2nd capacitor 26 High voltage transformer 27 Drive circuit 28 Oscillation determining section 29 Power supply voltage detecting section 30 Power supply polarity determining means 31 Clocking means 32 Counting means
───────────────────────────────────────────────────── フロントページの続き (72)発明者 石尾 嘉朗 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 末永 治雄 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 石崎 恵美子 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 守屋 英明 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Ｆターム(参考） 3K086 AA10 BA08 CB20 CD19 DA20 DB03 DB21 FA02 FA03 FA04 FA05 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiro Ishio 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Emiko Ishizaki 1006 Kadoma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Hideaki Moriya 1006 Odaka, Kadoma, Kadoma, Osaka Pref. CD19 DA20 DB03 DB21 FA02 FA03 FA04 FA05
Claims (9)
イッチ素子の直列接続体と、第１および第２のダイオー
ドの直列接続体を並列接続し、前記第１および第２のダ
イオードに各々並列に第１と第２のコンデンサを接続
し、前記第１および第２の逆導通可能な半導体スイッチ
素子の接続点と、前記第１および第２のダイオードの接
続点間に商用電源と高圧トランスの１次巻線の直列回路
を接続し、前記高圧トランスの２次巻線の出力は高圧整
流回路を介してマグネトロンを付勢し、前記第１および
第２の半導体スイッチ素子を駆動する駆動回路を有し、
前記駆動回路は前記第１および第２の半導体スイッチ素
子を相補的に駆動するとともに前記駆動回路は前記マグ
ネトロンの発振を検知する発振検知部を有し、前記発振
検知部は商用電源の電圧に応じて前記マグネトロンの発
振を判定する基準値を変化させる構成としたマグネトロ
ン駆動用電源。1. A series connection of first and second semiconductor switches capable of reverse conduction and a series connection of first and second diodes are connected in parallel, and the first and second diodes are connected in series. A first and a second capacitor are connected in parallel, and a commercial power supply and a high-voltage transformer are connected between a connection point of the first and second semiconductor switch elements capable of reverse conduction and a connection point of the first and second diodes. And a drive circuit for driving the first and second semiconductor switch elements by energizing a magnetron via a high-voltage rectifier circuit with an output of a secondary winding of the high-voltage transformer. Has,
The drive circuit complementarily drives the first and second semiconductor switch elements, and the drive circuit has an oscillation detection unit that detects oscillation of the magnetron, and the oscillation detection unit responds to a voltage of a commercial power supply. And a magnetron driving power supply configured to change a reference value for judging the oscillation of the magnetron.
する基準値は商用電源が定格電圧の時に極大となり前記
商用電源の電圧が定格電圧に対して増減した場合は基準
値を減ずる構成とした請求項１記載のマグネトロン駆動
用電源。2. A reference value by which an oscillation detector detects the oscillation of a magnetron is maximum when the commercial power supply is at a rated voltage, and is reduced when the voltage of the commercial power supply is increased or decreased with respect to the rated voltage. Item 7. A power supply for driving a magnetron according to Item 1.
する基準値に下限値を設定する構成とした請求項２記載
のマグネトロン駆動用電源。3. The power supply for driving a magnetron according to claim 2, wherein the oscillation detector sets a lower limit value to a reference value for judging the oscillation of the magnetron.
部を設け、発振検知部は前記電源電圧検知部の出力信号
に応じてマグネトロンの発振を判定する基準値を変化さ
せる構成とした請求項１ないし３のいすれか１項に記載
のマグネトロン駆動用電源。4. A power supply voltage detecting section for detecting a voltage of a commercial power supply, wherein the oscillation detecting section changes a reference value for judging magnetron oscillation in accordance with an output signal of the power supply voltage detecting section. 4. The power supply for driving a magnetron according to any one of items 1 to 3.
デンサの直列接続体の電圧を検出するよう構成した請求
項４記載のマグネトロン駆動用電源。5. The power supply for driving a magnetron according to claim 4, wherein the power supply voltage detecting section is configured to detect a voltage of a series connection of the first and second capacitors.
スの接続点の電圧を検出する構成とした請求項４記載の
マグネトロン駆動用電源。6. A power supply for driving a magnetron according to claim 4, wherein said power supply voltage detection section detects a voltage at a connection point between a commercial power supply and a step-up transformer.
を設け、商用電源の極性が正極あるいは負極いずれか一
方の極性のときのみ電源電圧検知部は商用電源の電圧を
検出する構成とした請求項６記載のマグネトロン駆動用
電源。7. A power supply voltage detecting unit for determining the polarity of a commercial power supply, wherein the power supply voltage detecting unit detects the voltage of the commercial power supply only when the polarity of the commercial power supply is either the positive polarity or the negative polarity. Item 7. A power supply for driving a magnetron according to Item 6.
ロンの発振を検出できない場合は再起動する構成とした
請求項１から７のいずれか１項に記載のマグネトロン駆
動用電源。8. The magnetron driving power supply according to claim 1, wherein a timer is provided to restart the magnetron when oscillation of the magnetron cannot be detected within a predetermined time.
が再起動を所定回数以上繰り返そうとした場合は動作を
停止する構成とした請求項８記載のマグネトロン駆動用
電源。9. The magnetron driving power supply according to claim 8, wherein a counting means is provided to stop the operation when the magnetron driving power supply attempts to restart more than a predetermined number of times.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001095748A JP3501137B2 (en) | 2001-03-29 | 2001-03-29 | Power supply for magnetron drive |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001095748A JP3501137B2 (en) | 2001-03-29 | 2001-03-29 | Power supply for magnetron drive |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002299033A true JP2002299033A (en) | 2002-10-11 |
| JP3501137B2 JP3501137B2 (en) | 2004-03-02 |
Family
ID=18949759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001095748A Expired - Fee Related JP3501137B2 (en) | 2001-03-29 | 2001-03-29 | Power supply for magnetron drive |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3501137B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020153624A (en) * | 2019-03-22 | 2020-09-24 | パナソニックＩｐマネジメント株式会社 | Dryer |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101485342B1 (en) * | 2013-10-31 | 2015-01-26 | 한국전기연구원 | Power supply unit for magnetron including protection circuit |
-
2001
- 2001-03-29 JP JP2001095748A patent/JP3501137B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020153624A (en) * | 2019-03-22 | 2020-09-24 | パナソニックＩｐマネジメント株式会社 | Dryer |
| JP7129650B2 (en) | 2019-03-22 | 2022-09-02 | パナソニックＩｐマネジメント株式会社 | Dryer |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3501137B2 (en) | 2004-03-02 |
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