JPH0359989A - High-frequency heating device - Google Patents
High-frequency heating deviceInfo
- Publication number
- JPH0359989A JPH0359989A JP19273689A JP19273689A JPH0359989A JP H0359989 A JPH0359989 A JP H0359989A JP 19273689 A JP19273689 A JP 19273689A JP 19273689 A JP19273689 A JP 19273689A JP H0359989 A JPH0359989 A JP H0359989A
- Authority
- JP
- Japan
- Prior art keywords
- inverter circuit
- heating device
- capacitor
- frequency heating
- smoothing
- 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.)
- Pending
Links
- 238000010438 heat treatment Methods 0.000 title claims description 15
- 239000003990 capacitor Substances 0.000 claims abstract description 25
- 238000009499 grossing Methods 0.000 claims abstract description 25
- 239000004065 semiconductor Substances 0.000 claims abstract description 14
- 230000001052 transient effect Effects 0.000 claims abstract description 9
- 238000010586 diagram Methods 0.000 description 8
- 238000004804 winding Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 238000002955 isolation Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Landscapes
- Control Of High-Frequency Heating Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
この発明は、電子レンジ等の高周波加熱装置に係り、特
にその電源部の改良に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-frequency heating device such as a microwave oven, and particularly relates to an improvement of a power supply section thereof.
［従来の技術］
第４図は従来の電子レンジの一例に用いられている高周
波加熱装置の回路図であり、図において。[Prior Art] FIG. 4 is a circuit diagram of a high-frequency heating device used in an example of a conventional microwave oven.
（１）は商用電源、（２）は整流器、（３）は平滑コン
デンサで、これらの部材によって直流電源部を構成して
いる。（７） 、 （８）及び（９）はそれぞれ高周波
高圧トランスの一次、二次及び三次巻線、（４）は共振
コンデンサ、’ （５）は−次巻線〈７〉に直列接続し
た半導体スイッチ、（６）は半導体スイッチ（５）に並
列接続した転流ダイオードで、これら部材によって高周
波スイッチングパワー回路となるインバータ回路を構成
している。また、二次巻線（８〉には高圧コンデンサ（
１０）及び高圧ダイオード（１１）を接続して、半波倍
電圧整流回路を構威し、高圧ダイオード（１１〉を介し
てマグネトロン（１２）に高圧絶縁トランスよりの高圧
電力を供給し、さらに。(1) is a commercial power supply, (2) is a rectifier, and (3) is a smoothing capacitor, and these components constitute a DC power supply section. (7), (8), and (9) are the primary, secondary, and tertiary windings of a high-frequency high-voltage transformer, (4) is a resonant capacitor, and (5) is a semiconductor connected in series with the negative winding <7>. The switch (6) is a commutating diode connected in parallel to the semiconductor switch (5), and these members constitute an inverter circuit serving as a high frequency switching power circuit. In addition, the secondary winding (8>) is equipped with a high voltage capacitor (
10) and a high-voltage diode (11) are connected to form a half-wave voltage doubler rectifier circuit, and high-voltage power from a high-voltage isolation transformer is supplied to the magnetron (12) via the high-voltage diode (11).
三次巻線（９）の端子間電圧はマグネトロン（１２）の
フィラメント（１２ａ）に印加してヒータ電力を供給す
ることによりマグネトロン（１２）を駆動し、これによ
り発射するマイクロ波を被加熱体（図示なし）に照射す
るようになっている。The voltage across the terminals of the tertiary winding (9) is applied to the filament (12a) of the magnetron (12) to supply heater power to drive the magnetron (12), thereby emitting microwaves to the heated object ( (not shown).
［発明が解決しようとする課題］
上記のような従来の高周波加熱装置では、力率を増大さ
せるために平滑コンデンサ（３）の容量を比較的小さく
しているので、インバータ回路のインピーダンスが低い
ことに起因して、電源投入時の位相位置によっては半導
体スイッチ（５）に対して過渡的に過電圧が印加するた
めに、高周波加熱装置の寿命を短くしてしまうような問
題点があった。[Problem to be solved by the invention] In the conventional high-frequency heating device as described above, the capacity of the smoothing capacitor (3) is made relatively small in order to increase the power factor, so the impedance of the inverter circuit is low. Due to this, an overvoltage may be transiently applied to the semiconductor switch (5) depending on the phase position when the power is turned on, resulting in a problem that the life of the high frequency heating device will be shortened.
この発明は上記のような課題を解消するためになされた
もので、簡単な部材の付加によって、電源投入時の半導
体スイッチに対する過渡的な過電圧の印加を抑制する高
周波加熱゛装置を得ることを目的とする。This invention was made to solve the above-mentioned problems, and its purpose is to provide a high-frequency heating device that suppresses the application of transient overvoltage to a semiconductor switch when power is turned on by adding simple members. shall be.
［課題を解決するための手段］
この発明に係る高周波加熱装置は、共振用コンデンサ、
半導体スイッチ及び転流ダイオードとで成るインバータ
回路に対する過渡的な過電流を印加を抑制するため、整
流平滑回路の平滑コンデンサに並列接続した抵抗を設け
るようにしたものである。[Means for Solving the Problems] A high-frequency heating device according to the present invention includes a resonance capacitor,
In order to suppress the application of transient overcurrent to the inverter circuit consisting of semiconductor switches and commutating diodes, a resistor is provided that is connected in parallel to the smoothing capacitor of the rectifying and smoothing circuit.
［作用］
この発明における並列接続の抵抗は、平滑コンデンサの
容量を増大することによる力率の低下を招くことなく、
整流平滑回路の平滑コンデンサの容量が小さくても、イ
ンバータ回路に対するインピーダンスを大きくして、電
源投入時における半導体スイッチに印加される過渡的な
電圧上昇を抑制する。[Function] The parallel-connected resistors of the present invention do not cause a decrease in power factor due to an increase in the capacitance of the smoothing capacitor.
Even if the capacity of the smoothing capacitor of the rectifying and smoothing circuit is small, the impedance to the inverter circuit is increased to suppress the transient voltage rise applied to the semiconductor switch when the power is turned on.
［実施例］
第１図はこの発明の一実施例による高周波加熱装置の回
路の構成図であり、（１）〜（（２）は従来の高周波加
熱装置を示した第４図における同符号の部分と同一であ
るので、その構成説明は省略する。[Embodiment] Fig. 1 is a circuit diagram of a high-frequency heating device according to an embodiment of the present invention, and (1) to (2) are the same reference numerals in Fig. 4, which shows a conventional high-frequency heating device. Since the parts are the same, the explanation of the structure will be omitted.
（１３）は平滑コンデンサ（３）と並列に接続した抵抗
であり、この抵抗（１３）によって共振コンデンサ（４
）、半導体スイッチ（５）、転流ダイオード（６〉及び
−次巻線（７）でなるインバータ回路のインピダンスを
下げ、電源投入時の過渡的な電圧上昇を抑制するように
しである。(13) is a resistor connected in parallel with the smoothing capacitor (3), and this resistor (13)
), a semiconductor switch (5), a free-wheeling diode (6), and a negative winding (7) to lower the impedance of the inverter circuit to suppress a transient voltage rise when the power is turned on.
上記のような構成のこの発明による高周波加熱装置の作
用を説明するために、上記の抵抗（１３〉を平滑コンデ
ンサ（３）に並列接続をしない場合のインバータ回路に
おける過度的な応答と、抵抗（３）を発明の構成通りに
並列接続した場合のインバータ回路の電源投入時におけ
る過渡的な電圧変動とを比較した実施例について述べる
。In order to explain the operation of the high-frequency heating device according to the present invention having the above-mentioned configuration, we will explain the transient response in the inverter circuit when the above-mentioned resistor (13〉) is not connected in parallel to the smoothing capacitor (3), and the resistance (13〉) An example will be described in which a transient voltage fluctuation at the time of power-on of an inverter circuit is compared when 3) is connected in parallel according to the configuration of the invention.
第２図（ａ） 、 （ｂ）は抵抗（１３）を平滑コンデ
ンサ（３）に並列接続しない場合における電源投入時の
半導体スイッチ（５〉等のスイッチング素子に印加され
る電圧と時間との関係を示す線図であり、（ａ）図は商
用電源を９０″の位相位置で投入した場合のスイッチン
グ素子に加わる電圧の挙動を示し、投入時の２４０ｖが
２６０ｍ５後に約１４０ｖになって、定常状態を保持す
る。（ｂ）図は同じく０°の位相位置で投入した場合の
スイッチング素子に加わる電圧を示し、投入直後より電
圧値の変動がなく、約１４０Ｖの印加状態を保持する。Figures 2 (a) and (b) show the relationship between the voltage applied to a switching element such as a semiconductor switch (5) when the power is turned on and time when the resistor (13) is not connected in parallel to the smoothing capacitor (3). Figure (a) shows the behavior of the voltage applied to the switching element when the commercial power supply is turned on at a phase position of 90'', and the 240V at the time of turning on becomes about 140V after 260m5, indicating a steady state. The figure (b) also shows the voltage applied to the switching element when the switching element is turned on at a phase position of 0°, and there is no change in the voltage value immediately after turning on, and the applied state of about 140 V is maintained.
このように、位相によって過電圧が発生するのは、力率
を上げるために平滑コンデンサ（３）の容量を小さくし
なければならないことに起因している。The reason why overvoltage occurs depending on the phase is that the capacity of the smoothing capacitor (3) must be reduced in order to increase the power factor.
第３図はこの発明による第１図の構成のように、平滑コ
ンデンサ（３）に抵抗（１３）を並列接続した場合の電
源投入時における半導体スイッチ（５）等のスイッチン
グ素子に印加される電圧と時間との関係の一例を示す線
図であり、図で明らかなように、投入時の位相位置が９
０″での商用電源では最大２００Ｖの電圧が加わるが３
０＋ｍｓの短時間で定常状態に移行する結果を得た。FIG. 3 shows the voltage applied to a switching element such as a semiconductor switch (5) when the power is turned on when a resistor (13) is connected in parallel to a smoothing capacitor (3) as in the configuration shown in FIG. 1 according to the present invention. This is a diagram showing an example of the relationship between
With a commercial power supply at 0", a maximum voltage of 200V is applied, but 3
A result was obtained in which a steady state was reached in a short time of 0+ms.
上記の例による説明のように、商用電源を直流に交換す
るために平滑コンデンサ（３）の容量は制約され、その
ために電源投入時の位相によっては過渡的に半導体スイ
ッチ（５〉等のスイッチング素子に過電圧が加わる。こ
の過電圧の発生を制約するためにインバータ回路のイン
ピーダンスを低下させる抵抗（１３〉を並列接続するこ
とによって、過電圧の値を低下させるとともに、短時間
で定常状態に移行できるようになる。As explained using the example above, the capacity of the smoothing capacitor (3) is limited in order to replace the commercial power supply with direct current, and therefore depending on the phase when the power is turned on, switching elements such as the semiconductor switch (5) In order to restrict the occurrence of this overvoltage, a resistor (13) that lowers the impedance of the inverter circuit is connected in parallel to reduce the overvoltage value and to enable a transition to a steady state in a short time. Become.
［発明の効果］
以上のように、この発明によれば、商用電源の直流化の
ための平滑コンデンサに並列抵抗を接続して、インバー
タ回路のインピーダンスを低下させるように構成したの
で、電源投入時のスイッチング素子に対する過電圧の発
生を抑制できるために、寿命の長い高周波加熱装置が得
られる効果がある。[Effects of the Invention] As described above, according to the present invention, since the impedance of the inverter circuit is reduced by connecting a parallel resistor to the smoothing capacitor for converting the commercial power supply to DC, the impedance of the inverter circuit is reduced. Since generation of overvoltage to the switching element can be suppressed, a high-frequency heating device with a long life can be obtained.
第１図はこの発明の一実施例による高周波加熱装置の回
路図、第２図は平滑コンデンサに並列抵抗を接続しない
場合の作用を説明するための線図、第３図はこの発明の
構成による並列抵抗を接続した場合の作用を説明するた
めの線図、第４図は従来の高周波加熱装置の回路図であ
る。
図において、（１）・・・商用電源、（２）・・・整流
器、（３）・・・平滑コンデンサ、（４）・・・共振コ
ンデンサ、（５）・・・半導体スイッチ、（６）・・・
転流ダイオード、（１２）・・・マグネトロン、（１３
）・・・抵抗である。
なお、図中同一符号は同−又は相当部分を示す。Fig. 1 is a circuit diagram of a high-frequency heating device according to an embodiment of the present invention, Fig. 2 is a diagram for explaining the effect when no parallel resistance is connected to the smoothing capacitor, and Fig. 3 is a diagram according to the configuration of the present invention. A diagram for explaining the effect when parallel resistances are connected, and FIG. 4 is a circuit diagram of a conventional high-frequency heating device. In the figure, (1)... Commercial power supply, (2)... Rectifier, (3)... Smoothing capacitor, (4)... Resonant capacitor, (5)... Semiconductor switch, (6)... ...
Commutating diode, (12)... Magnetron, (13
)...It is resistance. Note that the same reference numerals in the figures indicate the same or equivalent parts.
Claims (1)
路に接続された共振用コンデンサ、半導体スイッチ及び
転流ダイオードとで成るインバータ回路と、このインバ
ータ回路によって付勢されてマグネトロンに高圧パルス
を供給するとともに、上記マグネトロンのフィラメント
にヒータ電力を供給する高圧トランスとで成る高周波加
熱装置において、上記インバータ回路に対する過渡的な
過電圧の印加を抑制するため、上記整流平滑回路の平滑
コンデンサに並列接続した抵抗を設けたことを特徴とす
る高周波加熱装置。A rectifying and smoothing circuit connected to a commercial power supply, an inverter circuit consisting of a resonant capacitor, a semiconductor switch, and a commutating diode connected to this rectifying and smoothing circuit, and a high voltage pulse that is energized by this inverter circuit and supplied to the magnetron. In addition, in a high-frequency heating device consisting of a high-voltage transformer that supplies heater power to the filament of the magnetron, a resistor is connected in parallel to the smoothing capacitor of the rectifying and smoothing circuit in order to suppress the application of transient overvoltage to the inverter circuit. A high-frequency heating device characterized by being provided with.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19273689A JPH0359989A (en) | 1989-07-27 | 1989-07-27 | High-frequency heating device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19273689A JPH0359989A (en) | 1989-07-27 | 1989-07-27 | High-frequency heating device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0359989A true JPH0359989A (en) | 1991-03-14 |
Family
ID=16296210
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19273689A Pending JPH0359989A (en) | 1989-07-27 | 1989-07-27 | High-frequency heating device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0359989A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040018001A (en) * | 2002-08-24 | 2004-03-02 | 삼성전자주식회사 | Control circuit for high power level in a microwave oven |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59194384A (en) * | 1983-04-19 | 1984-11-05 | 三洋電機株式会社 | Drive circuit of magnetron |
| JPS62147971A (en) * | 1985-12-23 | 1987-07-01 | Matsushita Electric Works Ltd | Inverter unit |
-
1989
- 1989-07-27 JP JP19273689A patent/JPH0359989A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59194384A (en) * | 1983-04-19 | 1984-11-05 | 三洋電機株式会社 | Drive circuit of magnetron |
| JPS62147971A (en) * | 1985-12-23 | 1987-07-01 | Matsushita Electric Works Ltd | Inverter unit |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20040018001A (en) * | 2002-08-24 | 2004-03-02 | 삼성전자주식회사 | Control circuit for high power level in a microwave oven |
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