JP4007253B2

JP4007253B2 - Cooker

Info

Publication number: JP4007253B2
Application number: JP2003156404A
Authority: JP
Inventors: 裕二藤井; 泉生弘田; 貴宏宮内; 篤志藤田
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2003-06-02
Filing date: 2003-06-02
Publication date: 2007-11-14
Anticipated expiration: 2023-06-02
Also published as: JP2004362794A

Description

【０００１】
【発明の属する技術分野】
本発明は一般家庭やレストラン及びオフィス等で使用される複数の加熱部を有する加熱調理器に関するものである。
【０００２】
【従来の技術】
従来の加熱調理器の動作を誘導加熱調理器を例に取り上げ、図面を用いて説明する。図２は従来例の構成を示すブロック図である。
【０００３】
図２において、２１は交流電源、２２は２つの接点２２ａ、２２ｂから成る電源スイッチ、２３は接点２２ａの開閉により交流電源２１と接続の断続が成されると共に、交流電源２１を整流するブリッジ接続されたダイオードから成る第１の整流回路２４、第１のチョークコイル２５ａ及び第１のコンデンサ２５ｂから成る第１の平滑回路２５、第１の加熱コイル（図示せず）と第１のスイッチング素子（図示せず）を含む第１のインバータ回路２６から成る第１の加熱部、２７は接点２２ｂの開閉により交流電源２１と接続の断続が成されると共に、交流電源２１を整流するブリッジ接続されたダイオードから成る第２の整流回路２８、第２のチョークコイル２９ａ及び第２のコンデンサ２９ｂから成る第２の平滑回路２９、第２の加熱コイル（図示せず）と第２のスイッチング素子（図示せず）を含む第２のインバータ回路３０から成る第２の加熱部である。
【０００４】
上記構成において動作を説明する。使用者が本機器を使用する時には、まず、電源スイッチ２２を操作することにより、第１の接点２２ａ並びに第２の接点２２ｂを閉じる。この時、第１の接点２２ａには主に第１のコンデンサ２５ｂへ電荷充電のための突入電流、第２の接点２２ｂには主に第２のコンデンサ２９ｂへ電荷充電のための突入電流がそれぞれ流れる。第１の接点２２ａ並びに第２の接点２２ｂの開閉は、電源スイッチ２２の操作によって略同時に成される。
【０００５】
この後、使用者の操作部（図示せず）のキー操作等により、第１の加熱部２３または第２の加熱部２７の動作が開始され、第１の接点２２ａまたは第２の接点２２ｂには、最大で、対応する加熱部の定格電流がそれぞれ流れる。この時、第１のインバータ回路２６または第２のインバータ回路３０は交流電源２１を対応する第１の整流回路２４または第２の整流回路２８、及び第１の平滑回路２５または第２の平滑回路２９で整流、平滑した直流（第１のコンデンサ２５ｂまたは第２のコンデンサ２９ｂの静電容量が１０〜数十μＦの場合は略全波整流の脈流）を高周波交流に変換し、対応する加熱コイル（図示せず）に高周波電流を流すことで、加熱コイルと磁気結合した鍋等の被加熱体（図示せず）に渦電流を発生させて、そのジュール熱で被加熱体を誘導加熱するものである。
【０００６】
本従来例では第１の加熱部２３と第２の加熱部２７の定格消費電流が同等で、また第１の加熱部２３及び第２の加熱部２７の入力インピーダンスの静電容量成分の大半を占める第１のコンデンサ２５ｂ及び第２のコンデンサ２９ｂの静電容量も多くとも数十μＦで同等であるので、電源スイッチ２２の各加熱部に対応した第１の接点２２ａ及び第２の接点２２ｂに流れる、突入電流及び定格電流レベルも同等となり、第１の接点２２ａ及び第２の接点２２ｂの材質や形状は同等で良く、これらで構成する電源スイッチ２２の構造も簡潔にできると共に、電源スイッチ２２と第１の加熱部２３及び第２の加熱部２７との電気的接続に用いるリード線（図示せず）の接続関係を敢えて規定する必要がないので、機器組み立て時やサービス時の制約が緩和されると言う利点がある（例えば、構成においては特許文献１、突入電流対策においては特許文献２参照）。
【０００７】
【特許文献１】
特許第３３０９８２１号公報（第５−８頁、第１図）
【特許文献２】
特開平５−２９０９６５号公報（第３−４頁、第１図）
【０００８】
【発明が解決しようとする課題】
しかしながら、以上のような従来の加熱調理器では、第１の加熱部２３と第２の加熱部２７の定格消費電流が同等であっても、加熱対象とする負荷材質の相違等に起因する、第１のインバータ回路２６及び第２のインバータ回路３０の回路構成差や必要入力電圧形態の差（例えば脈流成分の大小等）等による第１の平滑回路２５及び第２の平滑回路２９のインダクタンス値及び静電容量値が大きく異なる場合、電源スイッチ２２の第１の接点２２ａ及び第２の接点２２ｂが閉じる際の第１のコンデンサ２５ｂ及び第２のコンデンサ２９ｂに流入する突入電流の振る舞いも大きく異なることになる。
【０００９】
従って、例えば第１のコンデンサ２５ｂの静電容量（約１０００μＦ）が第２のコンデンサ２９ｂのそれ（約１０μＦ）より甚だ大きい場合には、第１のチョークコイル２５ａと第２のチョークコイル２９ａとにインダクタンス値にも差を設けて突入電流のピーク値を抑えるにしろ、機器の実装スペースに制限があり、チョークコイル自体を大型化するには限界があり、十分なインダクタンス値を得られないため、第１の接点２２ａに流れる突入電流値の時間積は第２の接点２２ｂのそれより大きくなり、従来数百μＦの静電容量への突入電流に耐えるように設計された接点を持つ電源スイッチでは、耐えきれずに溶着してしまうと言う課題があった。
【００１０】
また、これに対応するため、この場合第１の接点２２ａの許容電流を大きくするということも考えられるが、特殊仕様の接点となるため汎用性に欠け、通常大型化、或いはコストアップが予想されると共に、コストアップ抑制のため第２の接点２２ｂを現状のままの接点容量のものとしたりすると、電源スイッチ２２と第１の加熱部２３及び第２の加熱部２７との電気的接続に用いるリード線（図示せず）の接続関係を規定する必要が生じ、機器組み立て時やサービス時の制約が発生すると言う課題を有していた。
【００１１】
本発明は、上記課題を解決するもので、１つの加熱部の入力インピーダンスの静電容量成分が大きく、電源スイッチを閉じる際の突入電流が大きくなり、それぞれの加熱部に対応した接続端に流れる突入電流量に不平衡が発生する場合でも、その不平衡を抑制し、それぞれの加熱部に対応した接続端の許容電流容量は従来並み、或いは、汎用性の有る範疇での増加に留め、使い勝手が良く、信頼性の高い加熱調理器を提供することを目的とする。
【００１２】
【課題を解決するための手段】
上記課題を解決するために本発明は、入複数の加熱部を有し、前記複数の加熱部の入力の一端は各々共通電位として交流電源の一端に接続し、前記複数の加熱部のうち入力インピーダンスの静電容量成分が他と異なる加熱部を少なくともひとつ有する加熱調理器であって、前記複数の加熱部の入力の他端各々と前記交流電源の他端とを前記複数の加熱部各々に対応して設けた複数の接続端を介して接続する電源スイッチと、前記電源スイッチの前記複数の加熱部側の各々の電位端を、入力インピーダンスの静電容量成分が大なる加熱部側から入力インピーダンスの静電容量成分の小なる加熱部側へバイパスするバイパス手段と、前記バイパス手段の動作を制御する制御手段とを有し、前記制御手段は、前記電源スイッチの各接続端が導通する際に、前記複数の加熱部に流入する電流量の偏りを抑制すべく、前記バイパス手段を動作させ、流入する電流量の少ない側の加熱部と前記交流電源とを接続する前記電源スイッチの接続端に電流を一部分配して流入させる構成としているので、少なくとも１つの加熱部の入力インピーダンスの静電容量成分が大きく、電源スイッチを閉じる際に対応する接続端への突入電流が大きくなり、それぞれの加熱部に対応した接続端に流れる突入電流量に不平衡が発生する場合でも、バイパス手段がその不平衡成分を他の接続端に分配して、その不平衡を抑制することができる。
【００１３】
【発明の実施の形態】
請求項１に記載の発明は、複数の加熱部を有し、前記複数の加熱部の入力の一端は各々共通電位として交流電源の一端に接続し、前記複数の加熱部のうち入力インピーダンスの静電容量成分が他と異なる加熱部を少なくともひとつ有する加熱調理器であって、前記複数の加熱部の入力の他端各々と前記交流電源の他端とを前記複数の加熱部各々に対応して設けた複数の接続端を介して接続する電源スイッチと、前記電源スイッチの前記複数の加熱部側の各々の電位端を、入力インピーダンスの静電容量成分が大なる加熱部側から入力インピーダンスの静電容量成分の小なる加熱部側へバイパスするバイパス手段と、前記バイパス手段の動作を制御する制御手段とを有し、前記制御手段は、前記電源スイッチの各接続端が導通する際に、前記複数の加熱部に流入する電流量の偏りを抑制すべく、前記バイパス手段を動作させ、流入する電流量の少ない側の加熱部と前記交流電源とを接続する前記電源スイッチの接続端に電流を一部分配して流入させる構成としているので、この手段により、電源スイッチの複数の接続端が導通・非導通となることで、複数の加熱部への電源の供給・非供給を選択することができる。これにより、複数の加熱部はそれぞれ対応する接続端を介して交流電源より電力供給を受け、この電力によって非加熱体を加熱することができる。
【００１４】
また、複数の接続端が導通する際に発生する突入電流は各加熱部の入力インピーダンスの静電容量成分や抵抗成分、インダクタンス成分に依り、その大きさや持続時間が異なるので、各加熱部の入力インピーダンスの静電容量成分や抵抗成分、インダクタンス成分がほぼ同等、例えば各々、静電容量成分が数十μＦ、インダクタンス成分が数百μＨ、抵抗成分数百ｍΩ程度の場合には、交流電源が商用電源であれば、接続端個々の定格許容実効電流が十数〜２０Ａ程度（加熱部の定格実効電流に対しても十分満足している）のもので、機器の耐用年数に見合った耐久性は確保される。
【００１５】
しかし、ある加熱部の入力インピーダンスの静電容量成分が上記の約十〜数十倍以上にもなると、この静電容量成分を充電するために発生する突入電流のエネルギーは膨大となり、動作時の定格実効電流を連続的に流すことによる発熱等の問題から抵抗成分を大きくできない機器においては、インダクタンス値を増加させる方策をとるが、機器への実装上の制約から十分な値を得ることができない（せいぜい約数ｍＨ）ことに加え、この方策では突入電流のエネルギー自体は大きく抑制できないので、結果としてこの加熱部と交流電源を接続する接続端は上記の定格実効電流のものでは耐えきれずに性能劣化、最悪破壊に至ってしまう。
【００１６】
更に、該当の接続端の定格実効電流容量を大きくする方策でも、形状的な機器実装の制約や、コストアップ抑制のため他の接続端を上記した接点容量のものとすると、電源スイッチと該当の加熱部及び他の加熱部との電気的接続に用いるリード線の接続関係を規定する必要が生じ、機器組み立て時やサービス時の制約が発生したり、或いは機構的に接続端を断続する形式の接続端（タンブラースイッチ等）では、操作性に支障が発生する場合がある。
【００１７】
この様な場合において、バイパス手段が電源スイッチの各接続端が導通する際、入力インピーダンスの静電容量成分が大なる加熱部を交流電源と接続する接続端の当該加熱部側から入力インピーダンスの静電容量成分が小なる加熱部を交流電源と接続する接続端へとバイパスし、この接続端にも一部、入力インピーダンスの静電容量成分が大なる加熱部を交流電源と接続する接続端に流れる突入電流を分流するので、入力インピーダンスの静電容量成分が大なる加熱部を交流電源と接続する接続端の許容電流容量を極端に大きくしたり、当該加熱部の入力インピーダンスのインダクタンス成分を極端に大きくすることなく、突入電流の不平衡を抑制できるという作用を有する。
【００１８】
請求項２に記載の発明は、請求項１に記載の構成に加え、電源スイッチの複数の接続端各々が、金属等の導電物質から成る接点で、且つ前記接点各々が前記電源スイッチの開閉動作に連動して略同時に開閉するよう構成しているので、この手段により、タンブラースイッチ等、既存の多極電源スイッチで、使用者の意志に応じて、交流電源から複数の加熱部への電源供給を行うことができるという作用を有する。
【００１９】
請求項３に記載の発明は、請求項２に記載の構成に加え、複数の接点の開閉を電気励磁で行う駆動回路を有する構成としているので、この手段により、使用者は、タッチ式キーを押すなどの簡単、軽微な動作で交流電源から複数の加熱部への電源供給を行うことができるという作用を有する。
【００２０】
請求項４に記載の発明は、請求項３に記載の構成に加え、接点の開閉状態を検知する接点検知手段を有し、駆動回路が前記接点の駆動信号の有無に応じた前記接点検知手段の入力が得られない場合に、対応する加熱部の動作を停止する構成としたものであり、この手段により、万一接点が溶着或いは閉じない等の故障を生じ、加熱部が使用者の意図とは関係なく加熱動作を継続する事態になっても、加熱部の動作を停止することにより、安全性を確保することができるという作用を有する。
【００２１】
請求項５に記載の発明は、請求項４に記載の構成に加え、報知手段を有し、駆動回路が接点の駆動信号の有無に応じた接点検知手段の入力が得られない場合に、加熱部の動作を停止していることを報知する構成としているので、この手段により、使用者に機器の異常状態を認知させて、適切な処置を講じることを促すことができるという作用を有する。
【００２２】
請求項６に記載の発明は、請求項１〜５に記載の構成に加え、複数の接続端の導通開始タイミング差が、入力インピーダンスの静電容量成分が大なる加熱部に流入する電流の流入時間未満である構成としているので、この手段により、各接続端の導通開始直後の突入電流の不平衡を確実に抑制することができるという作用を有する。
【００２３】
請求項７に記載の発明は、請求項１に記載の構成に加え、電源スイッチの複数の接続端各々が、半導体スイッチから成る構成としているので、この手段により、各半導体スイッチを同タイミングで駆動すれば、これら半導体スイッチの導通タイミングの個体差は数〜数十μ秒であり、入力インピーダンスの静電容量成分が大なる加熱部に流入する電流の流入時間未満に容易にすることができるので、各接続端の導通開始直後の突入電流の不平衡をより確実に抑制することができるという作用を有する。
【００２４】
請求項８に記載の発明は、請求項１〜７に記載の構成に加え、バイパス手段は電源スイッチの接続端が導通する際にバイパスし、少なくとも１つの加熱部が動作開始する際には非導通となる構成としているので、この手段により、突入電流の不平衡を抑制後に機器が動作可能になった時点で、バイパス手段のバイパス動作（導通状態）を停止して、非導通にすることで、各加熱部が同時動作する時に、各加熱部に対応する各接続端に流れる電流においては、接続端個々に対応加熱部の消費電流のみを負担するので、接続端の接触抵抗、導通抵抗、導通電圧の個体差等による接続端に流れる電流の不平衡を皆無にして、接続端の許容定格電流を超えることを防止するという作用を有する。
【００２５】
請求項９に記載の発明は、請求項１〜８に記載の構成に加え、バイパス手段は、金属等の導電物質から成る接点を備えると共に、前記接点の開閉を電気励磁で行う駆動回路が前記接点の開閉タイミングを制御する構成としているので、この手段により、駆動回路が所望のタイミングでこの接点の開閉を制御できるので、突入電流の不平衡を抑制後に、このバイパス手段の接点の導通状態を容易に非導通にし、各加熱部が同時動作する時に、各加熱部に対応する各接続端に流れる電流においては、接続端個々に対応加熱部の消費電流のみを負担するので、接続端の接触抵抗、導通抵抗、導通電圧の個体差等による接続端に流れる電流の不平衡を皆無にして、接続端の許容定格電流を超えることを防止するという作用を有する。
【００２６】
請求項１０に記載の発明は、請求項１〜８に記載の構成に加え、バイパス手段は、所定の導通電圧または所定の導通抵抗を有する両導通型半導体素子で構成しているので、この手段により、比較的小型、安価で突入電流耐性に優れる素子でバイパス手段を構成でき、バイパス手段搭載に関して、スペース制約のある機器においては、比較的容易に搭載できるという作用を有する。
【００２７】
請求項１１に記載の発明は、請求項１０に記載の構成とすると共に、両導通半導体素子は、互いに逆接続した２つのダイオードで構成としているので、この手段により、ダイオードの持つ導通電圧の存在により、突入電流の不平衡を抑制後に機器が動作可能になった時点で、バイパス手段のバイパス動作（導通状態）を停止して、非導通にすることで、各加熱部が同時動作する時に、各加熱部に対応する各接続端に流れる電流においては、接続端個々に対応加熱部の消費電流のみを負担するので、接続端の接触抵抗、導通抵抗、導通電圧の個体差等による接続端に流れる電流の不平衡を皆無にして、接続端の許容定格電流を超えることを防止すると共に、バイパス手段搭載に関して、駆動回路等が不要であるので、スペース制約のある機器においては、更に容易に搭載できるという作用を有する。
【００２８】
【実施例】
（実施例１）
以下本発明の実施例を誘導加熱調理器を例に取り上げ、図面に基づいて説明する。図１は本発明の第１の実施例の構成を示すブロック図である。
【００２９】
図１において、１は交流電源、２は２つの接続端２ａ、２ｂ（定格実効電流容量１６Ａ）から成る電源スイッチ、３は第１の接続端２ａの開閉により交流電源１と接続の断続が成されると共に、交流電源１を整流するブリッジ接続されたダイオードから成る第１の整流回路４、第１のチョークコイル５ａ（インダクタンス大、約３ｍＨ）及び第１のコンデンサ５ｂ（静電容量大、約１０００μＦ）から成る第１の平滑回路５、第１の加熱コイル（図示せず）と第１のスイッチング素子（図示せず）を含む第１のインバータ回路６から成る第１の加熱部、７は第２の接続端２ｂの開閉により交流電源１と接続の断続が成されると共に、交流電源１を整流するブリッジ接続されたダイオードから成る第２の整流回路８、第２のチョークコイル９ａ（インダクタンス小、約２００μＨ）及び第２のコンデンサ９ｂ（静電容量小、約１０μＦ）から成る第２の平滑回路９、第２の加熱コイル（図示せず）と第２のスイッチング素子（図示せず）を含む第２のインバータ回路１０から成る第２の加熱部、１１は電源スイッチ２の第１の加熱部３及び第２の加熱部７側各々の電位端を、第１の加熱部側から第２の加熱部７側へバイパスするバイパス手段、１２は、電源スイッチ２を電磁式リレー或いは半導体スイッチとした場合、これを導通・非導通にするための第１の駆動回路、１３は電源スイッチ２を電磁リレーとした場合に、第１の接続端（接点）２ａ及び第２の接続端（２ｂ）の対応する各加熱部側の電位を検出し、各接続端（接点）の導通・非導通状態を検知する接点検知手段、１４は電源スイッチ２を電磁リレーとした場合に、接点検知手段１３の出力を基に所望の情報を使用者に報知する報知手段、１５はバイパス手段１１が電磁リレーとした場合のリレー接点を導通・非導通にするための第２の駆動回路、１６は使用者が第１の加熱部３並びに第２の加熱部７を所望の動作状態に設定すると共に、これに応じて第１の加熱部３及び第２の加熱部７を動作させる信号を出力したり、第１の駆動回路１２及び第２の駆動回路１５を動作させる信号を出力たり、或いは接点検知手段１３の出力に応じて報知手段に所望の情報を使用者に報知する信号の出力を行う操作・制御回路（制御手段）である。
【００３０】
上記構成において動作を説明する。使用者が本機器を使用する時には、まず、電源スイッチ２がタンブラースイッチ等であれば、これを操作することにより、第１の接点２ａ並びに第２の接点２ｂを略同時に閉じる。
【００３１】
また、電源スイッチ２が電磁リレー或いは半導体スイッチの場合は、操作・制御回路１６のタクトスイッチを操作して第１の駆動回路１２に電磁リレー或いは半導体スイッチを導通状態にさせる。電源スイッチ２がタンブラースイッチ等であれば、使用者はある程度の操作力を必要とするが、電磁リレー或いは半導体スイッチであれば、上記のようにタクトスイッチを押すという簡単な操作で電源スイッチ２を動作させることができる。
【００３２】
この時、第１の接続端２ａには第１のコンデンサ５ｂへ電荷充電のための突入電流、第２の接続端２ｂには第２のコンデンサ９ｂへ電荷充電のための突入電流がそれぞれ流れようとするが、バイパス手段１１により、第１の接続端２ａと第２の接続端２ｂは各加熱部側から見て並列接続となることで、第１の接続端２ａと第２の接続端２ｂにそれぞれ流れるべき突入電流を略均等に分担する。これにより、バイパス手段１１が無ければ、静電容量大の第１のコンデンサ５ｂによる突入電流は第１の接続端２ａにのみ流れる所を、第１の接続端２ａ及び第２の接続端２ｂに分配することができる。このため、所望の耐久回数を満足せず溶着したり、破壊する等、１つの接続端では耐えられないような突入電流でも２つの接続端の並列接続により耐えるようにすることができる。
【００３３】
また、第１の接続端２ａの定格実効電流容量を大きくして（２０Ａ超）突入電流に対する耐性を向上せず、形状的な機器実装の制約や、コストアップ抑制のため第２の接続端２ｂと同じ上記した定格実効電流容量（１６Ａ）のものとできるので、電源スイッチと該当の加熱部及び他の加熱部との電気的接続に用いるリード線の接続関係を規定する必要もなく、機器組み立て時やサービス時の制約は発生しない。更に、第１の加熱部３の入力インピーダンスの静電容量成分は第２の加熱部７のそれの約１００倍にもなると、この静電容量成分を充電するために発生する突入電流のエネルギーは膨大であり、動作時の定格実効電流を連続的に流すことによる発熱等の問題から抵抗成分を大きくできない機器においては、インダクタンス値を増加させるにも、機器への実装上の制約から十分な値を得ることはできないし、突入電流のエネルギー自体は大きく抑制できないが、本実施例では、この状態においても、２つの接続端の並列接続により耐えるようにすることができる。
【００３４】
バイパス手段１１が電磁リレーである場合は、電源スイッチ２が導通状態になった直後或いは導通状態になる以前に第２の駆動回路１５により導通状態にされている。また、突入電流が流れ終わった後、例えば、本実施例では突入電流は約百ｍ秒以下で流れ終わるので、電源スイッチ２が導通してから５００ｍ秒後にバイパス手段１１の電磁リレーを非導通にして、第１の加熱部３または第２の加熱部７が動作する時に流れる定常電流は対応する第１の接続端２ａまたは第２の接続端２ｂそれぞれに流れるようにして、第１の加熱部３と第２の加熱部７が同時動作する時に、対応する第１の接続端２ａと第２の接続端２ｂに流れる電流においては、接続端個々に対応加熱部の消費電流のみを負担するので、接続端の接触抵抗、導通抵抗、導通電圧の個体差等による接続端に流れる電流の不平衡を皆無にして、接続端個々の許容定格電流を超えることを防止している。
【００３５】
バイパス手段１１が所定の導通電圧または所定の導通抵抗を有する両導通型半導体素子、本実施例では、互いに逆接続した２つのダイオードで形成、である場合は、電源スイッチ２が導通状態になった直後、突入電流が流れ出した瞬間にこの突入電流のエネルギーによって、第１の接続端２ａの第１の加熱部３側の電位端電圧と第２の接続端２ｂの第２の加熱部７側電位端電圧との差が、このダイオードの導通電圧略１Ｖを容易に超えるので、ダイオードが導通状態になり突入電流を第１の接続端２ａと第２の接続端２ｂに分配する。
【００３６】
また、突入電流のエネルギーが流れながら減衰していくので、第１の接続端２ａの第１の加熱部３側の電位端電圧と第２の接続端２ｂの第２の加熱部７側電位端電圧との差が、このダイオードの導通電圧略１Ｖを超えなくなると、バイパス手段１１のダイオードは非導通になる。これにより、第１の加熱部３または第２の加熱部７が動作する時に流れる定常電流は対応する第１の接続端２ａまたは第２の接続端２ｂそれぞれに流れるようにして、第１の加熱部３と第２の加熱部７が同時動作する時に、対応する第１の接続端２ａと第２の接続端２ｂに流れる電流においては、接続端個々に対応加熱部の消費電流のみを負担するので、接続端の接触抵抗、導通抵抗、導通電圧の個体差等による接続端に流れる電流の不平衡を皆無にして、接続端個々の許容定格電流を超えることを防止している。
【００３７】
第１の加熱部３または第２の加熱部７が動作する時には、第１の接続端２ａの第１の加熱部３側の電位端電圧と第２の接続端２ｂの第２の加熱部７側電位端電圧との差が、バイパス手段１１のダイオードの導通電圧略１Ｖを超えることはなく、バイパス手段１１の非導通状態は保たれる。この場合、バイパス手段１１が電磁リレーである時のように、第２の駆動回路１５を必要とせず、簡単な構成で、バイパス手段１１の導通・非導通を制御することができる。
【００３８】
バイパス手段１１が突入電流を第１の接続端２ａと第２の接続端２ｂに分配する際、第１の接続端２ａと第２の接続端２ｂとの導通開始タイミングが突入電流が流れている時間以上あると、突入電流の分配はできないが、突入電流が流れている時間未満、本実施例では第１の加熱部３への突入電流が流れている時間は略交流電源１の周期の略半分（略πラジアン）であり、第１の加熱部３への突入電流ピークはその略半分のπ／２ラジアン付近に発生するので、このピークを抑制するため第１の接続端２ａと第２の接続端２ｂとの導通開始タイミング差をπ／２ラジアン以下に設定している。これにより、各接続端の導通開始直後の突入電流の不平衡を確実に抑制することができる。
【００３９】
第１の加熱部３及び第２の加熱部７への突入電流流入後、電源スイッチ２が電磁リレーまたは半導体スイッチである時は、操作・制御回路１６が第１の駆動回路１２に出力している信号の状態と接点検知手段１３からの第１の接続端２ａ及び第２の接続端２ｂの導通状態の信号とを比較して、第１の駆動回路１２が第１の接続端２ａ及び第２の接続端２ｂを導通状態にしている信号を出しているにも関わらず、接点検知手段１３からの信号が非導通状態であったり、またその逆で第１の駆動回路１２が第１の接続端２ａ及び第２の接続端２ｂを非導通状態にしている信号を出しているにも関わらず、接点検知手段１３からの信号が導通状態であった場合は、故障であると判断して、該当する接続端側の加熱部を動作停止すると共に、報知手段１４によりその旨を使用者に報知する。
【００４０】
故障でないと判断すれば、使用者の操作・制御回路１６へのキー操作等により、第１の加熱部３または第２の加熱部７の動作が開始され、第１の接点２ａまたは第２の接点２ｂには、最大で、対応する加熱部の定格電流がそれぞれ流れる。この時、第１のインバータ回路６または第２のインバータ回路１０は交流電源１を対応する第１の整流回路４または第２の整流回路８、及び第１の平滑回路５または第２の平滑回路９で整流、平滑した直流（第１のコンデンサ５ｂまたは第２のコンデンサ９ｂの静電容量値により、脈流成分を持っている）を高周波交流に変換し、対応する加熱コイル（図示せず）に高周波電流を流すことで、加熱コイルと磁気結合した鍋等の被加熱体（図示せず）に渦電流を発生させて、そのジュール熱で被加熱体を誘導加熱するものである。
【００４１】
尚、本実施例では、加熱部を２つの入力インピーダンスの静電容量成分が異なる誘導加熱方式の構成で説明してあるが、３つ以上有する構成であっても同様の効果が得られるのは言うまでもないことである。また、すべての加熱部が入力インピーダンスの静電容量成分を有する必要もなく、抵抗成分のみのヒーターが含まれていても良い。
【００４２】
【発明の効果】
以上の説明から明らかなように、請求項１〜１１記載の発明によれば、入力インピーダンスの静電容量成分が大なる加熱部のインダクタンス成分や抵抗成分を機器実装不可能なまで大きくすることなく、また、入力インピーダンスの静電容量成分が大なる加熱部に対応する接続端の許容実効電流も大きくせず、機器組み立て時やサービス時の制約を発生させずに、入力インピーダンスの静電容量成分が大なる加熱部への突入電流に耐えうる電源スイッチを形成した加熱調理器を実現することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施例の構成を示すブロック図
【図２】従来例の構成を示すブロック図
【符号の説明】
１交流電源
２電源スイッチ
２ａ第１の接続端
２ｂ第２の接続端
３第１の加熱部
７第２の加熱部
１１バイパス手段
１２第１の駆動回路
１３接点検知手段
１４報知手段
１５第２の駆動回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooking device having a plurality of heating units used in general homes, restaurants and offices.
[0002]
[Prior art]
The operation of a conventional cooking device will be described with reference to the drawings, taking an induction cooking device as an example. FIG. 2 is a block diagram showing a configuration of a conventional example.
[0003]
In FIG. 2, 21 is an AC power source, 22 is a power switch composed of two contacts 22a and 22b, and 23 is connected to the AC power source 21 by opening and closing the contact 22a, and is bridged to rectify the AC power source 21. A first rectifier circuit 24 composed of a diode, a first smoothing circuit 25 composed of a first choke coil 25a and a first capacitor 25b, a first heating coil (not shown) and a first switching element ( The first heating unit 27 including the first inverter circuit 26 including the first inverter circuit 26 (not shown) is intermittently connected to the AC power source 21 by opening / closing the contact 22b, and is bridge-connected to rectify the AC power source 21. The second rectifier circuit 28 composed of a diode, the second smoothing circuit 29 composed of the second choke coil 29a and the second capacitor 29b, the second heating circuit Le is a second heating portion of a second inverter circuit 30 including the (not shown) and a second switching element (not shown).
[0004]
The operation in the above configuration will be described. When the user uses this apparatus, first, the first contact 22a and the second contact 22b are closed by operating the power switch 22. At this time, the first contact 22a mainly has an inrush current for charging the first capacitor 25b, and the second contact 22b has an inrush current mainly for charging the second capacitor 29b. Flowing. The first contact 22 a and the second contact 22 b are opened and closed substantially simultaneously by operating the power switch 22.
[0005]
Thereafter, the operation of the first heating unit 23 or the second heating unit 27 is started by a key operation or the like of the operation unit (not shown) by the user, and the first contact 22a or the second contact 22b is activated. The maximum rated current of the corresponding heating part flows. At this time, the first inverter circuit 26 or the second inverter circuit 30 includes the first rectifier circuit 24 or the second rectifier circuit 28 corresponding to the AC power supply 21, and the first smoothing circuit 25 or the second smoothing circuit. The direct current rectified and smoothed at 29 (if the first capacitor 25b or the second capacitor 29b has a capacitance of 10 to several tens of μF) is converted into a high-frequency alternating current, and the corresponding heating is performed. By passing a high-frequency current through a coil (not shown), an eddy current is generated in a heated object (not shown) such as a pan magnetically coupled to the heating coil, and the heated object is induction-heated by the Joule heat. Is.
[0006]
In this conventional example, the rated current consumption of the first heating unit 23 and the second heating unit 27 is equal, and most of the capacitance components of the input impedances of the first heating unit 23 and the second heating unit 27 are reduced. Since the capacitance of the first capacitor 25b and the second capacitor 29b occupied is equal to at most several tens of μF, the first contact 22a and the second contact 22b corresponding to each heating part of the power switch 22 are connected to each other. The flowing inrush current and the rated current level are equivalent, and the material and shape of the first contact 22a and the second contact 22b may be the same, and the structure of the power switch 22 constituted by these can be simplified, and the power switch 22 Since it is not necessary to stipulate the connection relationship of lead wires (not shown) used for electrical connection between the first heating unit 23 and the second heating unit 27, restrictions at the time of device assembly and service There is an advantage that is alleviated (e.g., see Patent Document 2 in Patent Document 1, the inrush current measures in the structure).
[0007]
[Patent Document 1]
Japanese Patent No. 3309821 (page 5-8, Fig. 1)
[Patent Document 2]
JP-A-5-290965 (page 3-4, FIG. 1)
[0008]
[Problems to be solved by the invention]
However, in the conventional cooking device as described above, even if the rated current consumption of the first heating unit 23 and the second heating unit 27 is the same, due to the difference in the load material to be heated, etc. Inductance of the first smoothing circuit 25 and the second smoothing circuit 29 due to a difference in circuit configuration between the first inverter circuit 26 and the second inverter circuit 30 and a difference in required input voltage form (for example, the magnitude of the pulsating current component). When the value and the capacitance value are greatly different, the behavior of the inrush current flowing into the first capacitor 25b and the second capacitor 29b when the first contact 22a and the second contact 22b of the power switch 22 are closed is also large. Will be different.
[0009]
Therefore, for example, when the capacitance (about 1000 μF) of the first capacitor 25b is much larger than that (about 10 μF) of the second capacitor 29b, the first choke coil 25a and the second choke coil 29a Even if there is a difference in the inductance value to suppress the peak value of the inrush current, there is a limit to the equipment mounting space, there is a limit to increasing the size of the choke coil itself, and a sufficient inductance value can not be obtained, The time product of the inrush current value flowing through the first contact 22a is larger than that of the second contact 22b. Conventionally, in a power switch having a contact designed to withstand an inrush current to a capacitance of several hundred μF. , There was a problem of welding without being able to endure.
[0010]
In order to cope with this, it may be considered that the allowable current of the first contact 22a is increased in this case, but since it is a contact of a special specification, it is not versatile and is normally expected to increase in size or cost. In addition, if the second contact 22b has the same contact capacity as the current one in order to suppress an increase in cost, it is used for electrical connection between the power switch 22 and the first heating unit 23 and the second heating unit 27. There is a need to define the connection relationship of lead wires (not shown), and there is a problem that restrictions at the time of device assembly and service occur.
[0011]
The present invention solves the above-described problem, and the capacitance component of the input impedance of one heating unit is large, the inrush current when closing the power switch is large, and flows to the connection end corresponding to each heating unit. Even if an unbalance occurs in the amount of inrush current, the unbalance is suppressed, and the allowable current capacity at the connection end corresponding to each heating unit is limited to an increase in the conventional or general category. An object is to provide a heating cooker that is good and reliable.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention has a plurality of heating units, and one end of each of the plurality of heating units is connected to one end of an AC power source as a common potential, and the input of the plurality of heating units is input. Cooking with at least one heating part that has a different electrostatic capacitance component from the others In a vessel A power switch for connecting each of the other input ends of the plurality of heating units and the other end of the AC power supply via a plurality of connection ends provided corresponding to each of the plurality of heating units; Bypass means for bypassing each potential end of the plurality of heating parts of the switch from the heating part side where the capacitance component of the input impedance is large to the heating part side where the capacitance component of the input impedance is small; Control means for controlling the operation of the bypass means, the control means, in order to suppress the bias of the amount of current flowing into the plurality of heating portions when each connection end of the power switch is conducted, Since the bypass means is operated and the current is partially distributed to the connection end of the power switch that connects the heating unit on the side where the amount of current flowing in is small and the AC power supply, at least one additional current is supplied. The capacitance component of the input impedance of the part is large, the inrush current to the connection end corresponding to closing the power switch is large, and an unbalance occurs in the amount of inrush current flowing to the connection end corresponding to each heating part Even in this case, the bypass means can distribute the unbalanced component to the other connection ends to suppress the unbalance.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 includes a plurality of heating units, and one end of each input of the plurality of heating units is connected to one end of an AC power source as a common potential, and the input impedance of the plurality of heating units is static. Cooking with at least one heating unit with a different capacitance component In a vessel A power switch for connecting each of the other input ends of the plurality of heating units and the other end of the AC power supply via a plurality of connection ends provided corresponding to each of the plurality of heating units; Bypass means for bypassing each potential end of the plurality of heating parts of the switch from the heating part side where the capacitance component of the input impedance is large to the heating part side where the capacitance component of the input impedance is small; Control means for controlling the operation of the bypass means, the control means, in order to suppress the bias of the amount of current flowing into the plurality of heating portions when each connection end of the power switch is conducted, By operating the bypass means, the current is partially distributed and introduced into the connection end of the power switch that connects the heating unit on the side with a smaller amount of inflow current and the AC power supply. By multiple connection terminal of the switch is rendered conductive and non-conductive, it is possible to select the power supply and non-supply to the plurality of heating portions. Thereby, a some heating part receives electric power supply from AC power supply via the corresponding connection end, respectively, and can heat a non-heating body with this electric power.
[0014]
Also, the inrush current generated when a plurality of connection ends become conductive depends on the capacitance component, resistance component, and inductance component of the input impedance of each heating unit. When the capacitance component, resistance component, and inductance component of the impedance are almost equal, for example, when the capacitance component is several tens μF, the inductance component is several hundred μH, and the resistance component is about several hundred mΩ, an AC power source is commercial If it is a power supply, the rated allowable effective current of each connection end is about 10 to 20 A (which is sufficiently satisfied with the rated effective current of the heating part), and the durability corresponding to the service life of the equipment is Secured.
[0015]
However, if the capacitance component of the input impedance of a certain heating unit is about ten to several tens of times the above, the energy of the inrush current generated to charge this capacitance component becomes enormous, For devices that cannot increase the resistance component due to problems such as heat generation due to continuous flow of the rated effective current, measures are taken to increase the inductance value, but sufficient values cannot be obtained due to restrictions on mounting on the device. In addition to this (at most about several mH), the energy of the inrush current itself cannot be greatly suppressed by this measure. As a result, the connecting end connecting the heating unit and the AC power source cannot withstand the above rated effective current. It will lead to performance degradation and worst destruction.
[0016]
Furthermore, even in the measure to increase the rated effective current capacity of the corresponding connection end, if the other connection ends have the above-mentioned contact capacities in order to limit the mounting of the equipment in shape or to suppress the cost increase, the power switch and the corresponding It is necessary to define the connection relationship of the lead wires used for electrical connection with the heating unit and other heating units, which may cause restrictions during assembly and service, or mechanically interrupt the connection end At the connection end (such as a tumbler switch), the operability may be hindered.
[0017]
In such a case, when the bypass means is connected to each connection end of the power switch, the input impedance is statically connected from the heating section side of the connection end connecting the heating section having a large capacitance component of the input impedance to the AC power supply. Bypass the heating part with a small capacitance component to the connection end connected to the AC power supply, and also at this connection end, the heating part with a large capacitance component of the input impedance to the connection end connected to the AC power supply Since the inrush current that flows is shunted, the allowable current capacity of the connection end that connects the heating section with a large capacitance component of the input impedance to the AC power supply is extremely increased, or the inductance component of the input impedance of the heating section is extremely large. In this case, the inrush current imbalance can be suppressed without increasing the current.
[0018]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, each of the plurality of connection ends of the power switch is a contact made of a conductive material such as metal, and each of the contacts is an opening / closing operation of the power switch. Since it is configured to open and close at the same time in conjunction with the power supply, it is possible to supply power from the AC power supply to multiple heating units according to the user's intention using existing multipolar power switches such as tumbler switches. It has the effect | action that can be performed.
[0019]
Since the invention according to claim 3 has a drive circuit that performs opening and closing of the plurality of contacts by electrical excitation in addition to the structure according to claim 2, this means allows the user to touch the touch key. It has an effect that power can be supplied from an AC power source to a plurality of heating units with a simple and light operation such as pressing.
[0020]
According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, the contact detection means for detecting the open / closed state of the contact is provided, and the contact detection means according to the presence or absence of a drive signal of the contact. If this input is not obtained, the operation of the corresponding heating unit is stopped. By this means, a failure such as the contact not being welded or closed occurs, and the heating unit is not intended by the user. Even if it becomes the situation which continues heating operation irrespective of, it has the effect | action that safety | security can be ensured by stopping operation | movement of a heating part.
[0021]
The invention according to claim 5 has a notification means in addition to the structure according to claim 4, and the heating circuit is heated when the input of the contact detection means according to the presence / absence of the contact drive signal cannot be obtained. Since it is configured to notify that the operation of the unit is stopped, this means has an effect that the user can be made aware of the abnormal state of the device and can be encouraged to take appropriate measures.
[0022]
In addition to the structure of Claims 1-5, the invention of Claim 6 is the inflow of the electric current which flows into the heating part from which the conduction | electrical_connection start timing difference of several connection ends becomes large in the electrostatic capacitance component of input impedance. Since the configuration is less than the time, this means has an effect that the inrush current imbalance immediately after the start of conduction at each connection end can be surely suppressed.
[0023]
According to the seventh aspect of the present invention, in addition to the configuration of the first aspect, each of the plurality of connection ends of the power switch is composed of a semiconductor switch. By this means, each semiconductor switch is driven at the same timing. If this is the case, the individual difference in the conduction timing of these semiconductor switches is several to several tens of microseconds, which can be easily made less than the inflow time of the current flowing into the heating section where the capacitance component of the input impedance is large. And, it has the effect that the imbalance of the inrush current immediately after the start of conduction at each connection end can be more reliably suppressed.
[0024]
According to an eighth aspect of the present invention, in addition to the configuration according to the first to seventh aspects, the bypass means bypasses when the connection end of the power switch is conducted, and does not operate when at least one heating unit starts operation. Since it is configured to be conductive, by this means, when the device becomes operable after suppressing the imbalance of the inrush current, the bypass operation (conductive state) of the bypass means is stopped and made non-conductive. In the current flowing through each connection end corresponding to each heating unit when each heating unit operates simultaneously, only the current consumption of the corresponding heating unit is borne by each connection end, so the contact resistance, conduction resistance of the connection end, This has the effect of preventing the current flowing through the connection end from being unbalanced due to individual differences in conduction voltage, etc., and preventing the allowable rated current at the connection end from being exceeded.
[0025]
According to a ninth aspect of the present invention, in addition to the configurations of the first to eighth aspects, the bypass means includes a contact made of a conductive material such as a metal, and a drive circuit that opens and closes the contact by electrical excitation is provided. Since it is configured to control the contact opening / closing timing, this means that the drive circuit can control the opening / closing of this contact at a desired timing, so that the conduction state of the contact of this bypass means can be changed after suppressing the inrush current imbalance. Since the current flowing through each connection end corresponding to each heating unit is easily made nonconductive and the current flowing through each connection end corresponding to each heating unit bears only the consumption current of the corresponding heating unit for each connection end. It has the effect of eliminating the unbalance of the current flowing through the connection end due to individual differences in resistance, conduction resistance, conduction voltage, etc., and preventing exceeding the allowable rated current at the connection end.
[0026]
In the invention described in claim 10, in addition to the structure described in claims 1-8, the bypass means is constituted by a both-conduction type semiconductor element having a predetermined conduction voltage or a predetermined conduction resistance. Thus, the bypass means can be configured with a relatively small, inexpensive, and excellent inrush current resistance, and it has an effect that the bypass means can be mounted relatively easily in a device with space restrictions.
[0027]
The invention described in claim 11 has the configuration described in claim 10, and both conductive semiconductor elements are configured by two diodes connected in reverse to each other. By stopping the bypass operation (conducting state) of the bypass means when the device becomes operable after suppressing the imbalance of inrush current, when each heating unit operates simultaneously, In the current flowing through each connection end corresponding to each heating unit, only the consumption current of the corresponding heating unit is borne by each connection end, so the connection end due to contact resistance, conduction resistance, individual differences in conduction voltage, etc. It eliminates the imbalance of the flowing current and prevents it from exceeding the allowable rated current at the connection end. Information, such an action can be more easily mounted.
[0028]
【Example】
Example 1
Embodiments of the present invention will be described below with reference to the drawings, taking an induction heating cooker as an example. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention.
[0029]
In FIG. 1, 1 is an AC power source, 2 is a power switch composed of two connection ends 2a and 2b (rated effective current capacity 16A), and 3 is intermittently connected to the AC power source 1 by opening and closing the first connection end 2a. And a first rectifier circuit 4 comprising a bridge-connected diode for rectifying the AC power source 1, a first choke coil 5a (large inductance, about 3 mH), and a first capacitor 5b (large capacitance, about A first smoothing circuit 5 composed of 1000 μF, a first heating unit composed of a first inverter circuit 6 including a first heating coil (not shown) and a first switching element (not shown), The connection and disconnection of the AC power supply 1 are made by opening and closing the second connection end 2b, and the second rectifier circuit 8 and the second choke coil 9a each composed of a bridge-connected diode that rectifies the AC power supply 1. A second smoothing circuit 9 comprising a small inductance, about 200 μH) and a second capacitor 9 b (small capacitance, about 10 μF), a second heating coil (not shown) and a second switching element (not shown). ) Including a second inverter circuit 10 including a second inverter circuit 10, and 11 indicates a potential end of each of the first heating unit 3 and the second heating unit 7 side of the power switch 2 from the first heating unit side. Bypass means for bypassing to the second heating unit 7 side, 12 is a first drive circuit for making the power switch 2 conductive or non-conductive when the power switch 2 is an electromagnetic relay or semiconductor switch, and 13 is a power switch 2 is an electromagnetic relay, the potential of each heating unit corresponding to the first connection end (contact point) 2a and the second connection end (2b) is detected, and conduction / non-connection of each connection end (contact point) is detected. Contact detection means 14 for detecting the conduction state, When the source switch 2 is an electromagnetic relay, notification means for notifying a user of desired information based on the output of the contact detection means 13, 15 is a conductive / non-conductive relay contact when the bypass means 11 is an electromagnetic relay. The second drive circuit 16 for conducting is configured so that the user sets the first heating unit 3 and the second heating unit 7 to a desired operation state, and the first heating unit 3 and A signal for operating the second heating unit 7 is output, a signal for operating the first drive circuit 12 and the second drive circuit 15 is output, or the notification means is desired according to the output of the contact detection means 13. This is an operation / control circuit (control means) for outputting a signal for informing the user of the above information.
[0030]
The operation in the above configuration will be described. When the user uses the device, first, if the power switch 2 is a tumbler switch or the like, the first contact 2a and the second contact 2b are closed substantially simultaneously by operating the switch.
[0031]
When the power switch 2 is an electromagnetic relay or a semiconductor switch, the tact switch of the operation / control circuit 16 is operated to cause the first drive circuit 12 to turn on the electromagnetic relay or the semiconductor switch. If the power switch 2 is a tumbler switch or the like, the user needs a certain amount of operating force. If the power switch 2 is an electromagnetic relay or a semiconductor switch, the power switch 2 can be easily operated by pressing the tact switch as described above. It can be operated.
[0032]
At this time, an inrush current for charging the electric charge to the first capacitor 5b flows through the first connection terminal 2a, and an inrush current for the electric charge charging to the second capacitor 9b flows through the second connection terminal 2b. However, by the bypass means 11, the first connection end 2a and the second connection end 2b are connected in parallel when viewed from the respective heating unit sides, whereby the first connection end 2a and the second connection end 2b. The inrush currents that should flow through each of them are shared substantially evenly. Thereby, if there is no bypass means 11, the place where the inrush current due to the first capacitor 5b having a large capacitance flows only to the first connection end 2a is transferred to the first connection end 2a and the second connection end 2b. Can be distributed. For this reason, it is possible to withstand an inrush current that cannot be withstood by one connection end by parallel connection of the two connection ends, such as welding or breaking without satisfying the desired durability.
[0033]
In addition, the rated effective current capacity of the first connection end 2a is increased (over 20A), and the resistance to inrush current is not improved. Since it can have the same rated effective current capacity (16A) as above, it is not necessary to define the connection relationship of the lead wires used for the electrical connection between the power switch, the corresponding heating unit and other heating units, and the assembly of equipment There are no time or service restrictions. Furthermore, when the capacitance component of the input impedance of the first heating unit 3 is about 100 times that of the second heating unit 7, the energy of the inrush current generated to charge the capacitance component is For devices that are enormous and that cannot increase the resistance component due to problems such as heat generation caused by continuous flow of the rated effective current during operation, sufficient values can be obtained due to mounting restrictions on the device, even though the inductance value cannot be increased. In this embodiment, even in this state, it is possible to withstand the parallel connection of the two connection ends.
[0034]
When the bypass means 11 is an electromagnetic relay, the second drive circuit 15 is in a conductive state immediately after the power switch 2 is in a conductive state or before the power switch 2 is in a conductive state. In addition, for example, in this embodiment, the inrush current stops flowing in about 100 milliseconds or less after the inrush current has ended. Therefore, the electromagnetic relay of the bypass means 11 is made non-conductive 500 milliseconds after the power switch 2 is turned on. The steady heating current that flows when the first heating unit 3 or the second heating unit 7 is operated flows to the corresponding first connection end 2a or second connection end 2b, respectively, so that the first heating unit 3 and the second heating unit 7 simultaneously operate, the current flowing through the corresponding first connection end 2a and second connection end 2b bears only the current consumption of the corresponding heating unit for each connection end. The current flowing through the connection end due to contact resistance at the connection end, conduction resistance, individual differences in conduction voltage, etc. is eliminated, and the allowable rated current of each connection end is prevented from exceeding.
[0035]
In the case where the bypass means 11 is a both-conduction type semiconductor element having a predetermined conduction voltage or a predetermined conduction resistance, in this embodiment, formed by two diodes reversely connected to each other, the power switch 2 is in a conduction state. Immediately after that, at the moment when the inrush current starts to flow, the energy of the inrush current causes the potential end voltage on the first heating unit 3 side of the first connection end 2a and the potential on the second heating unit 7 side of the second connection end 2b. Since the difference from the end voltage easily exceeds the diode conduction voltage of approximately 1 V, the diode becomes conductive, and the inrush current is distributed to the first connection end 2a and the second connection end 2b.
[0036]
Further, since the energy of the inrush current is attenuated while flowing, the potential end voltage on the first heating unit 3 side of the first connection end 2a and the potential end on the second heating unit 7 side of the second connection end 2b When the difference from the voltage does not exceed approximately 1 V, the diode of the bypass means 11 becomes non-conductive. Accordingly, the steady heating current that flows when the first heating unit 3 or the second heating unit 7 operates is caused to flow to the corresponding first connection end 2a or second connection end 2b, respectively. When the unit 3 and the second heating unit 7 operate simultaneously, the current flowing through the corresponding first connection end 2a and second connection end 2b bears only the consumption current of the corresponding heating unit for each connection end. Therefore, the current flowing through the connection end due to contact resistance at the connection end, conduction resistance, individual differences in conduction voltage, etc. is eliminated, and the allowable rated current of each connection end is not exceeded.
[0037]
When the first heating unit 3 or the second heating unit 7 operates, the potential end voltage on the first heating unit 3 side of the first connection end 2a and the second heating unit 7 of the second connection end 2b. The difference from the side potential terminal voltage does not exceed the conduction voltage of the diode of the bypass unit 11 of about 1 V, and the non-conduction state of the bypass unit 11 is maintained. In this case, unlike the case where the bypass unit 11 is an electromagnetic relay, the second drive circuit 15 is not required, and conduction / non-conduction of the bypass unit 11 can be controlled with a simple configuration.
[0038]
When the bypass means 11 distributes the inrush current to the first connection end 2a and the second connection end 2b, the inrush current flows due to the conduction start timing between the first connection end 2a and the second connection end 2b. If the time is longer than the time, the inrush current cannot be distributed. However, in the present embodiment, the time during which the inrush current flows to the first heating unit 3 is less than the period of the AC power supply 1 in the present embodiment. Since it is half (approximately π radians), the inrush current peak to the first heating unit 3 is generated in the vicinity of approximately half π / 2 radians. Therefore, in order to suppress this peak, the first connection end 2 a and the second The conduction start timing difference with the connection end 2b is set to π / 2 radians or less. Thereby, the imbalance of the inrush current immediately after the start of conduction at each connection end can be reliably suppressed.
[0039]
After the inrush current flows into the first heating unit 3 and the second heating unit 7, when the power switch 2 is an electromagnetic relay or a semiconductor switch, the operation / control circuit 16 outputs to the first drive circuit 12. The first drive circuit 12 compares the first connection terminal 2a and the second connection terminal 2b with the first connection terminal 2a and the second connection terminal 2b. 2, the signal from the contact detection means 13 is in the non-conductive state, and vice versa, the first drive circuit 12 is in the first state. If the signal from the contact detection means 13 is in a conductive state despite the fact that the signal that makes the connection end 2a and the second connection end 2b nonconductive is output, it is determined that there is a failure. In addition, the operation of the heating part on the corresponding connection end side is stopped, and the notification means 4 by informing the fact to the user.
[0040]
If it is determined that there is no failure, the operation of the first heating unit 3 or the second heating unit 7 is started by the user's operation to the operation / control circuit 16 or the like, and the first contact 2a or the second contact is started. The rated current of the corresponding heating part flows through the contact 2b at the maximum. At this time, the first inverter circuit 6 or the second inverter circuit 10 includes the first rectifier circuit 4 or the second rectifier circuit 8 corresponding to the AC power supply 1, and the first smoothing circuit 5 or the second smoothing circuit. The direct current rectified and smoothed at 9 (having a pulsating flow component depending on the capacitance value of the first capacitor 5b or the second capacitor 9b) is converted into a high-frequency alternating current, and a corresponding heating coil (not shown) By causing a high-frequency current to flow, an eddy current is generated in a heated object (not shown) such as a pan magnetically coupled to the heating coil, and the heated object is induction-heated by the Joule heat.
[0041]
In this embodiment, the heating unit has been described with the configuration of the induction heating system in which the capacitance components of the two input impedances are different, but the same effect can be obtained even with a configuration having three or more. Needless to say. Moreover, it is not necessary for all the heating parts to have a capacitance component of input impedance, and a heater having only a resistance component may be included.
[0042]
【The invention's effect】
As is apparent from the above description, according to the inventions of claims 1 to 11, without increasing the inductance component or the resistance component of the heating part in which the electrostatic capacitance component of the input impedance is large until the device cannot be mounted. In addition, the allowable effective current at the connection end corresponding to the heating part where the capacitance component of the input impedance is large does not increase, and the capacitance component of the input impedance does not cause restrictions during assembly or service. Therefore, it is possible to realize a heating cooker in which a power switch that can withstand an inrush current to the heating portion is formed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a conventional example
[Explanation of symbols]
1 AC power supply
2 Power switch
2a First connection end
2b Second connection end
3 First heating section
7 Second heating section
11 Bypass means
12 First drive circuit
13 Contact detection means
14 Notification means
15 Second drive circuit

Claims

A heating unit having a plurality of heating units, one end of the input of each of the plurality of heating units is connected to one end of an AC power source as a common potential, and the capacitance component of the input impedance is different from the other among the plurality of heating units the a heating cooker having at least one, via a plurality of connection terminals provided in correspondence with the other end of each and of the AC power source and the other end of the input of the plurality of heating unit to the plurality of heating portions each The power switch to be connected and the potential end of each of the plurality of heating units of the power switch are connected to the heating unit side where the capacitance component of the input impedance is small from the heating unit side where the capacitance component of the input impedance is large. Bypass means, and control means for controlling the operation of the bypass means, wherein the control means is a current that flows into the plurality of heating sections when each connection end of the power switch is conductive. In order to suppress the unevenness of the heating cooker, the bypass means is operated to partially distribute the current to the connection end of the power switch that connects the heating unit on the side where the amount of current flowing in is small and the AC power supply. .

2. The power switch according to claim 1, wherein each of the plurality of connection ends is a contact made of a conductive material such as metal, and each of the contacts is configured to open and close substantially simultaneously with the opening and closing operation of the power switch. Cooking cooker.

The cooking device according to claim 2, further comprising a drive circuit that opens and closes the plurality of contacts by electrical excitation.

Contact detecting means for detecting the open / closed state of the contact, and the control means operates the corresponding heating unit when the input of the contact detecting means according to the presence or absence of the drive signal of the contact cannot be obtained. The cooking device according to claim 3, wherein the cooking is stopped.

5. A notification means is provided, and the control means notifies that the operation of the heating section is stopped when the drive circuit cannot obtain the input of the contact detection means according to the presence or absence of the contact drive signal. The heating cooker described in 1.

The cooking device according to any one of claims 1 to 5, wherein the time difference between the conduction start timings of the plurality of connection ends is less than the inflow time of the current flowing into the heating unit in which the capacitance component of the input impedance is large.

The cooking device according to claim 1, wherein each of the plurality of connection ends of the power switch is formed of a semiconductor switch.

The heating cooker according to any one of claims 1 to 7, wherein the bypass means bypasses when the connection end of the power switch is conductive, and becomes non-conductive when at least one heating unit starts operation. .

The bypass means includes a contact made of a conductive material such as a metal, and a drive circuit that opens and closes the contact by electrical excitation controls the opening and closing timing of the contact. Cooking device.

The cooking device according to any one of claims 1 to 8, wherein the bypass means is configured by a both-conduction type semiconductor element having a predetermined conduction voltage or a predetermined conduction resistance.

The cooking device according to claim 10, wherein each of the conductive semiconductor elements is composed of two diodes connected in reverse to each other.