JPS6127113Y2

JPS6127113Y2 -

Info

Publication number: JPS6127113Y2
Application number: JP18936583U
Authority: JP
Priority date: 1983-12-08
Filing date: 1983-12-08
Publication date: 1986-08-13
Also published as: JPS59158292U

Description

【考案の詳細な説明】本考案は誘導加熱調理器に関し、その目的とす
るところはインバータ最大出力電力を負荷の種
類、あるいは電源電圧に応じて安定的に制御する
ことにある。[Detailed Description of the Invention] The present invention relates to an induction heating cooker, and its purpose is to stably control the maximum output power of an inverter according to the type of load or power supply voltage.

インバータの最大出力電力は負荷あるいは入力
電源電圧により変動するのが通常である。このた
め入力電流あるいは出力電流を検知し、これを制
御回路に帰還させて、出力制御をする必要があ
る。しかし入力電流を一定にすべくインバータ出
力を制御する場合には直接インバータ回路の出力
波形を検知していないためインバータ回路構成部
品の耐量を越える波形が印加する恐れがある。 The maximum output power of an inverter usually varies depending on the load or input power supply voltage. Therefore, it is necessary to detect the input current or output current and feed it back to the control circuit to control the output. However, when controlling the inverter output to keep the input current constant, the output waveform of the inverter circuit is not directly detected, so there is a risk that a waveform that exceeds the tolerance of the inverter circuit components may be applied.

一方インバータ回路の出力電流、電圧を検知し
てそれを一定にすべくインバータ出力を制御した
場合には、電源電圧が低下した際に入力電流が増
大し、定流定格を越えたり、整流器等の部品温度
上昇が増大する。冷却システムの電源を入力電源
からとつている場合には部品冷却条件はさらに悪
化する。 On the other hand, if the output current and voltage of the inverter circuit are detected and the inverter output is controlled to keep them constant, the input current will increase when the power supply voltage drops, and may exceed the constant current rating or cause the rectifier, etc. Part temperature rise increases. Component cooling conditions are further exacerbated when the cooling system is powered from the input power source.

そこで入力電流とインバータ出力を同時に、検
知し制御手段にフイードバツクする必要がある。
従来は第１図に示すように入力電流検知回路４と
出力電流検知回路５のオアをとり、両者の出力の
上限値で一定パワー制御するように比較器８と制
御手段９でインバータ２を制御するシステムがあ
る。 Therefore, it is necessary to simultaneously detect the input current and the inverter output and provide feedback to the control means.
Conventionally, as shown in FIG. 1, the input current detection circuit 4 and the output current detection circuit 5 are ORed, and the inverter 2 is controlled by the comparator 8 and the control means 9 so as to perform constant power control at the upper limit of the output of both. There is a system to do that.

本考案は前記システムに於て出力電流検知手段
のかわりにインバータの共振回路部品の印加電圧
検知手段を採用したものである。 The present invention employs voltage detection means applied to the resonant circuit components of the inverter in place of the output current detection means in the system.

第２図に本実施例の構成を示す。破線Ａで示す
インバータ回路の構成部品１３′の印加電圧検知
回路１５と入力電流検知回路１２の出力電圧をオ
ア回路１６に入力しオア回路の出力をインバータ
発振制御回路１４に入力し、入力電流、インバー
タ部品の印加電圧いずれか一方の上限値で最大出
力制御しようとするものである。 FIG. 2 shows the configuration of this embodiment. The output voltages of the applied voltage detection circuit 15 and the input current detection circuit 12 of the component 13' of the inverter circuit shown by the broken line A are input to the OR circuit 16, and the output of the OR circuit is input to the inverter oscillation control circuit 14, and the input current, This attempts to control the maximum output using the upper limit value of either one of the voltages applied to the inverter components.

次に一具体例を述べる。第３図にトランジスタ
インバータを示す。この図で１８は電源整流器、
１９は電源コンデンサ、２０はダンパダイオー
ド、２１はスイツチングトランジスタ、２２は転
流コンデンサ、２３は加熱コイル（転流コイ
ル）、２４は加熱コイル電圧検知回路、２５，２
６はオア回路を構成するダイオード、２７は入力
電流検知回路、２８はトランジスタのオン時間を
制御するベース電流印加時間制御回路である。第
４図に電流検知回路２７と、加熱コイル電圧検知
回路２４の構成例を示す。次に動作を説明する。
基本のパワーコントロールはトランジスタ２１の
ベース電流のオン時間（第５図ｂのT₁）で行い、
T₁が大になるほど加熱コイル２３に流れる電流
が増大し出力電力が増加する。 Next, a specific example will be described. FIG. 3 shows a transistor inverter. In this diagram, 18 is the power rectifier,
19 is a power supply capacitor, 20 is a damper diode, 21 is a switching transistor, 22 is a commutation capacitor, 23 is a heating coil (commutation coil), 24 is a heating coil voltage detection circuit, 25, 2
6 is a diode constituting an OR circuit, 27 is an input current detection circuit, and 28 is a base current application time control circuit that controls the ON time of the transistor. FIG. 4 shows an example of the configuration of the current detection circuit 27 and the heating coil voltage detection circuit 24. Next, the operation will be explained.
Basic power control is performed by the on-time of the base current of the transistor 21 (T ₁ in Figure 5b).
As T ₁ becomes larger, the current flowing through the heating coil 23 increases and the output power increases.

T₁は制御回路２８内で第５図ａに示すように
のこぎり波と基準電圧Ｖ_Dとを比較器の基準に入
力しのこぎり波が立ち上がつてからＶ_Dに達する
までの時間で決定される。T₂は加熱コイル２３
と転流コンデンサ２２のトランジスタがオフして
からの共振期間であり、第５図ｃに示すＶ_Lの共
振時の波形の後縁（Ｏ電位を切るとき）でのこぎ
り波は立ち下がる。 T ₁ is determined in the control circuit 28 by inputting the sawtooth wave and _the reference voltage V _D as the reference of the comparator as shown in FIG. Ru. T ₂ is heating coil 23
This is the resonance period after the transistor of the commutating capacitor 22 is turned off, and the sawtooth wave falls at the trailing edge (when the O potential is cut) of the waveform during resonance of V _L shown in FIG. 5c.

入力電流が増大した場合、第４図の変流器４３
と２９〜３６のダイオード、コンデンサ、抵抗か
らなる整流回路で検出され比較器４２の−入力に
入つている電圧が増大し、直流電源Ｖ_CCと抵抗３
７，３８からなる基準電圧（比較器４２の＋入
力）を越えると比較器の出力がLoに下がりダイ
オード２５を介して制御回路２８の基準電圧Ｖ_D
（第５図ａ）を下げオン時間T₁が短くなりパワー
は下がる。結局入力電流検知回路の比較器の基準
電圧に対応する入力電力の上限値で安定する。 When the input current increases, the current transformer 43 in FIG.
The voltage detected by the rectifier circuit consisting of diodes, capacitors, and resistors 29 to 36 and input to the - input of comparator 42 increases, and the voltage that is input to the - input of comparator 42 increases, and the voltage increases between DC power supply V _CC and resistor 3.
When the reference voltage (+input of the comparator 42) exceeds the reference voltage consisting of 7 and 38, the output of the comparator falls to Lo and the reference voltage V _D of the control circuit 28 is passed through the diode 25.
(Fig. 5a) is lowered, the on time _T1 becomes shorter and the power decreases. Eventually, the input power stabilizes at the upper limit value corresponding to the reference voltage of the comparator of the input current detection circuit.

一方加熱コイルの端子電圧Ｖ_L（第５図ｃ）が
増大した場合（Ｖ_Lは共振時負電圧になる）Ｖ_L検
知回路２４のＥ点の電位は負方向に増大する。こ
のとき、４４〜５４の整流回路により検出された
比較器５５の＋入力電圧（Ｆ点の電位、抵抗５
４、コンデンサ４９で＋にバイアスされている）
が下がり、抵抗３７，３８で設定されている基準
電圧（比較器５５の−入力）より低くなれば比較
器５５の出力はLoになり、ダイオード２６を介
して、入力電流が増大した場合と同様、制御回路
３８の基準電圧Ｖ_Dを下げ出力電力を下げる。結
局Ｖ_L検知回路の比較器の基準電位で設定される
Ｖ_Lの上限値でパワー制御されることになる。第
４図の回路では前記二種の検出回路をダイオード
２５と２６でオア回路を構成しているため入力電
流、加熱コイル印加電圧いずれか一方が設定値を
越えた場合その上限値で最大入力電圧制御でき
る。 On the other hand, when the terminal voltage V _L (FIG. 5c) of the heating coil increases (V _L becomes a negative voltage at resonance), the potential at point E of the V _L detection circuit 24 increases in the negative direction. At this time, the +input voltage of the comparator 55 detected by the rectifier circuits 44 to 54 (potential at point F, resistor 5
4. Biased to + by capacitor 49)
When the voltage decreases and becomes lower than the reference voltage (-input of comparator 55) set by resistors 37 and 38, the output of comparator 55 becomes Lo, which is the same as when the input current increases through diode 26. , lowers the reference voltage V _D of the control circuit 38 and lowers the output power. After all, the power is controlled by the upper limit value of V _L set by the reference potential of the comparator of the V _L detection circuit. In the circuit shown in Fig. 4, the two types of detection circuits described above are constituted by an OR circuit with diodes 25 and 26, so if either the input current or the voltage applied to the heating coil exceeds the set value, the maximum input voltage is set to the upper limit value. Can be controlled.

以上の説明から明らかなように、本考案によれ
ば最大入力電力制御方式を採用することにより負
荷変動によるインバータ部品の保護、電源電圧変
動による消費電力、入力電流制御を効果的にでき
安定なインバータ動作を保障できるものである。
たとえば第３図のインバータ回路に於て、Ｖ_L一
定制御は、出力一定制御と同等であり標準動作電
源電圧に於て入力電流制御の設定消費電力とＶ_L
制御による入力電力の設定値を同一にした場合に
は第６図のような制御特性が得られる。 As is clear from the above explanation, according to the present invention, by adopting the maximum input power control method, it is possible to effectively protect inverter components due to load fluctuations, control power consumption due to power supply voltage fluctuations, and control input current, resulting in a stable inverter. The operation can be guaranteed.
For example, in the inverter circuit shown in Figure 3, constant V _L control is equivalent to constant output control, and the set power consumption of input current control and V _L
When the set value of input power by control is made the same, control characteristics as shown in FIG. 6 are obtained.

[Brief explanation of the drawing]

第１図は従来の誘導加熱調理器の回路図、第２
図，第３図は本考案の一実施例における誘導加熱
調理器の回路図、第４図は同回路図、第５図ａ，
ｂ，ｃは同動作波形図、第６図は同特性図であ
る。２……インバータ回路、３……加熱コイル、４
……入力電流検知手段、５……出力電流検知手
段、６……オア回路、８……比較回路、９……制
御手段、１３……インバータ共振回路、１４……
インバータ制御回路、１５……電圧検知手段、１
６……オア回路、１９……電源コンデンサ、２０
……ダンパ・ダイオード、２１……スイツチング
トランジスタ、２２……転流コンデンサ、２３…
…転流コイル、２４……電圧検知手段、２５，２
６……オア回路構成ダイオード。 Figure 1 is a circuit diagram of a conventional induction heating cooker, Figure 2 is a circuit diagram of a conventional induction heating cooker.
Figure 3 is a circuit diagram of an induction heating cooker according to an embodiment of the present invention, Figure 4 is the same circuit diagram, Figure 5 a,
b and c are waveform diagrams of the same operation, and FIG. 6 is a characteristic diagram of the same. 2... Inverter circuit, 3... Heating coil, 4
... Input current detection means, 5 ... Output current detection means, 6 ... OR circuit, 8 ... Comparison circuit, 9 ... Control means, 13 ... Inverter resonance circuit, 14 ...
Inverter control circuit, 15... Voltage detection means, 1
6...OR circuit, 19...Power supply capacitor, 20
... Damper diode, 21 ... Switching transistor, 22 ... Commutation capacitor, 23 ...
... Commutation coil, 24 ... Voltage detection means, 25, 2
6...OR circuit configuration diode.

Claims

[Scope of utility model registration request]

An inverter circuit is configured by a series circuit of a heating coil and a transistor connected to an output terminal of a full-wave rectifier, and a commutation capacitor connected between an interconnection point of this series circuit and one output terminal of the full-wave rectifier. and means for detecting a voltage corresponding to the input current to the inverter circuit, and means for detecting a voltage applied to a resonant element or a switching element constituting the inverter circuit, each of the detecting means The output is connected to an OR circuit via first and second comparators that share a predetermined reference voltage, and the output of this OR circuit is input to an inverter control means that continuously controls the on-time of the transistor. An induction heating cooker configured to set both input voltages of the OR circuit to the same value under a predetermined load condition, and perform maximum output suppression control of the inverter circuit by varying the ON time of the transistor. .