JP3475643B2 - Overvoltage prevention method by step-down chopper circuit - Google Patents
Overvoltage prevention method by step-down chopper circuitInfo
- Publication number
- JP3475643B2 JP3475643B2 JP05432996A JP5432996A JP3475643B2 JP 3475643 B2 JP3475643 B2 JP 3475643B2 JP 05432996 A JP05432996 A JP 05432996A JP 5432996 A JP5432996 A JP 5432996A JP 3475643 B2 JP3475643 B2 JP 3475643B2
- Authority
- JP
- Japan
- Prior art keywords
- switching element
- load
- circuit
- chopper circuit
- switch element
- 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.)
- Expired - Fee Related
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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、降圧チョッパ回路
に係り、例えば誘導加熱分野に適用される高周波電源装
置においてその電圧又は電力制御部を受け持つ降圧チョ
ッパ回路の負荷（インバータ等）の過電圧保護に用いて
有効な降圧チョッパ回路による負荷の過電圧防止方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-down chopper circuit, for example, for overvoltage protection of a load (inverter or the like) of the step-down chopper circuit which is responsible for the voltage or power control unit of a high frequency power supply device applied to the field of induction heating. The present invention relates to a method of effectively preventing load overvoltage by a step-down chopper circuit.
【０００２】[0002]
【従来の技術】通常、降圧チョッパ回路は図３に示す回
路で構成される。すなわち、図３において１は直流コン
デンサ、２は直流リアクトル、３は平滑コンデンサ、４
は負荷、５はスイッチ素子、６は還流ダイオードであっ
て、スイッチ素子５はトランジスタやＩＧＢＴ等の半導
体素子からなる。2. Description of the Related Art Normally, a step-down chopper circuit is composed of the circuit shown in FIG. That is, in FIG. 3, 1 is a DC capacitor, 2 is a DC reactor, 3 is a smoothing capacitor, 4
Is a load, 5 is a switch element, and 6 is a freewheeling diode. The switch element 5 is a semiconductor element such as a transistor or an IGBT.
【０００３】図３の降圧チョッパ回路において、スイッ
チ素子５のオン，オフ時間を制御し、Ｖｏ＝｛ＴON／
（ＴON＋ＴOFF）｝×Ｖｉの出力電圧を得る。ここで、
Ｖｉは入力電圧、Ｖｏは出力電圧、ＴONはオン時間、Ｔ
OFFはオフ時間である。In the step-down chopper circuit of FIG. 3, the on / off time of the switch element 5 is controlled so that Vo = {T ON /
An output voltage of (T ON + T OFF )} × Vi is obtained. here,
Vi is the input voltage, Vo is the output voltage, T ON is the on time, T
OFF is the off time.
【０００４】この場合、オン，オフ制御を行うスイッチ
素子５がショートモードで破損すると、降圧チョッパ回
路の入力電圧Ｖｉがそのまま出力電圧Ｖｏとなり、負荷
回路（インバータ等）へ印加される。In this case, when the switch element 5 for controlling on / off is damaged in the short mode, the input voltage Vi of the step-down chopper circuit becomes the output voltage Vo as it is and is applied to the load circuit (inverter or the like).
【０００５】[0005]
【発明が解決しようとする課題】１００ＫＨｚを越える
周波数を必要とする高周波電源装置においては、降圧チ
ョッパ回路の負荷回路（インバータ）としてＭＯＳＦＥ
Ｔが使用される場合が多く、降圧チョッパ回路の入力電
圧が、通常運転中にそのままインバータへ印加されると
スイッチ素子の破損につながる。したがって、印加され
ても問題のない高耐圧素子を選定する必要がある。In a high frequency power supply device requiring a frequency exceeding 100 KHz, a MOSFE is used as a load circuit (inverter) of a step-down chopper circuit.
In many cases, T is used, and if the input voltage of the step-down chopper circuit is directly applied to the inverter during normal operation, the switch element will be damaged. Therefore, it is necessary to select a high breakdown voltage element that causes no problem even when applied.
【０００６】本発明は上述の問題点に鑑みてなされたも
ので、その目的とするところは、負荷回路に過電圧が印
加される時間を最小にできる降圧チョッパ回路による過
電圧防止方法を提供することである。[0006] The present invention has been made in view of the above problems, and an object, over by the step-down chopper circuit which can time an overvoltage is applied to the load circuit to a minimum
It is to provide a voltage prevention method .
【０００７】[0007]
【課題を解決するための手段】上記の目的を達成するた
めに、直流電源に第１のスイッチ素子及び直流リアクト
ルと平滑コンデンサよりなる平滑回路を介して負荷を接
続し、且つ、第１のスイッチ素子と直流リアクトルとの
接続点と負荷の負極間に還流ダイオードを逆並列に接続
した第２のスイッチング素子を有するチョッパ回路にお
いて、前記第１のスイッチング素子と第２のスイッチン
グ素子の動作を相反してオン，オフ制御させると共に、
第２のスイッチング素子のオン時間を第１のスイッチン
グ素子のオフ時間より短くし、第１のスイッチング素子
のショート事故時に第２のスイッチング素子を介して電
流を流すことを特徴としたものである。In order to achieve the above object, a direct current power source includes a first switching element and a direct current reactor.
The load through a smoothing circuit consisting of
And the connection between the first switching element and the DC reactor
A freewheeling diode is connected in anti-parallel between the connection point and the negative electrode of the load.
In the chopper circuit having the second switching element
And the first switching element and the second switching element.
While controlling the operation of the switching element on and off contradictoryly,
The ON time of the second switching element is set to the first switch
The switching time shorter than the off time of the switching element
In case of a short-circuit accident of the
It is characterized by flowing a flow .
【０００８】また、第１のスイッチ素子と直列に保護ヒ
ューズを設けて構成したことを特徴としたものである。Further , a protective filter is connected in series with the first switch element.
It is characterized by having a fuse .
【０００９】[0009]
【発明の実施の形態】以下に本発明の実施の形態につい
て図１と図２を参照しながら説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.
【００１０】図１は本発明の実施の形態を示す降圧チョ
ッパ回路を示すもので、直流コンデンサ１には保護ヒュ
ーズ７を介してスイッチ素子５が接続されているととも
に、保護ヒューズ７，スイッチ素子５および直流リアク
トル２を介して平滑コンデンサ３が並列に接続されてい
る。平滑コンデンサ３には負荷４が並列に接続される。
また、還流素子である還流ダイオード６に第２のスイッ
チ素子８を並列接続して並列回路９を形成し、この並列
回路９は保護ヒューズ７と第１のスイッチ素子５を介し
て直流コンデンサ１に並列接続されている。FIG. 1 shows a step-down chopper circuit according to an embodiment of the present invention, in which a switching element 5 is connected to a DC capacitor 1 via a protective fuse 7, and a protective fuse 7 and a switching element 5 are provided. Further, the smoothing capacitor 3 is connected in parallel via the DC reactor 2. A load 4 is connected in parallel to the smoothing capacitor 3.
Further, the freewheeling diode 6, which is a freewheeling element, is connected in parallel with the second switch element 8 to form a parallel circuit 9. The parallel circuit 9 is connected to the DC capacitor 1 via the protective fuse 7 and the first switch element 5. It is connected in parallel.
【００１１】図１のチョッパ回路において、スイッチ素
子５をオン，オフ制御することにより負荷に供給する直
流電力を制御する。すなわち、スイッチ素子５をオンに
すると、該スイッチ素子５，直流リアクトル２を通して
負荷４に電流が流れ、スイッチ素子５をオフにすると負
荷側から還流ダイオードを通して電流が流れる。In the chopper circuit of FIG. 1, the switch element 5 is turned on / off to control the DC power supplied to the load. That is, when the switch element 5 is turned on, a current flows through the load element 4 through the switch element 5 and the DC reactor 2, and when the switch element 5 is turned off, a current flows through the return diode from the load side.
【００１２】第１のスイッチ素子５と第２のスイッチ素
子８は図２に示すタイミングでオン，オフ動作させる。
図２において波形Ｌ1は第１のスイッチ素子５の動作タ
イムチャート、波形Ｌ2は第２のスイッチ素子８の動作
タイムチャートであり、ｔｄはデッドタイムである。The first switch element 5 and the second switch element 8 are turned on and off at the timing shown in FIG.
In FIG. 2, a waveform L 1 is an operation time chart of the first switch element 5, a waveform L 2 is an operation time chart of the second switch element 8, and td is a dead time.
【００１３】通常は、第１のスイッチ素子５のオン，オ
フ動作と並列回路９の動作に応じて負荷４に直流電力が
供給される。ここで、第１のスイッチ素子５のみがショ
ートすると、チョッパ回路の入力電圧Ｖｉが負荷４に印
加されるが第２のスイッチ素子８のオン動作により保護
ヒューズ７，スイッチ素子５および第２のスイッチ素子
８により短絡ループが形成され、保護ヒューズ７の溶断
により短絡ループが開になる。これにより負荷４に流れ
る電流がしゃ断される。Normally, DC power is supplied to the load 4 in accordance with the on / off operation of the first switch element 5 and the operation of the parallel circuit 9. Here, when only the first switch element 5 is short-circuited, the input voltage Vi of the chopper circuit is applied to the load 4, but the protection fuse 7, the switch element 5, and the second switch are turned on by the ON operation of the second switch element 8. A short circuit loop is formed by the element 8 and the short circuit loop is opened by blowing the protective fuse 7. As a result, the current flowing through the load 4 is cut off.
【００１４】第２のスイッチ素子８のみがショート破損
されると、並列回路９は双方向導通状態となり、第１の
スイッチ素子５がオンになると保護ヒューズ７，第１の
スイッチ素子５および第２のスイッチ素子８からなる短
絡ループが形成され、保護ヒューズ７が溶断して負荷４
が保護される。また、第１の保護スイッチ５と第２のス
イッチ素子の双方がショート破損した場合も同様であ
る。[0014] Only the second switching element 8 is short break, the parallel circuit 9 becomes bidirectional conduction state, the first switching element 5 and the protection fuse 7 is turned on, the first switching element 5 and the A short circuit loop composed of the switch element 8 of No. 2 is formed, the protective fuse 7 is blown, and the load 4
Is protected. The same applies when both the first protection switch 5 and the second switch element are short-circuited and damaged.
【００１５】すなわち、通常は、還流ダイオード６が動
作してチョッパ回路の動作となるが、第１のスイッチ素
子５又は第１のスイッチ素子８のいずれかがショート破
損した場合、図２に示すように第１のスイッチ素子５と
第２のスイッチ素子８を相反してオン，オフ動作させる
ことにより、最悪の場合でも半サイクル後には直流短絡
モードとなり、健全素子も破損させ、保護ヒューズ７に
より負荷保護と火災防止協調をとっている。That is, normally, the freewheeling diode 6 operates to operate the chopper circuit, but when either the first switch element 5 or the first switch element 8 is short-circuited and damaged, as shown in FIG. Moreover, by turning on and off the first switching element 5 and the second switching element 8 contradictory to each other, even in the worst case, the DC short-circuit mode occurs after half a cycle, and the sound element is also damaged, and the protective fuse 7 causes a load. Coordinates protection and fire prevention.
【００１６】[0016]
【発明の効果】本発明は、以上の如くであって、チョッ
パ回路の負荷となるインバータ等の負荷回路に過電圧が
印加される時間を最小限にでき、負荷回路の破損を防止
できるとともに、負荷回路において経済的な回路素子の
選定が可能になる。As described above, the present invention is capable of minimizing the time during which an overvoltage is applied to a load circuit such as an inverter, which serves as a load of a chopper circuit, preventing damage to the load circuit, and Allows economical selection of circuit elements in the circuit.
【図１】本発明の実施例による降圧チョッパ回路の模式
図。FIG. 1 is a schematic diagram of a step-down chopper circuit according to an embodiment of the present invention.
【図２】図１の降圧チョッパ回路におけるスイッチ素子
のオン，オフ波形図。2 is an ON / OFF waveform diagram of a switch element in the step-down chopper circuit of FIG.
【図３】従来の降圧チョッパ回路の模式図。FIG. 3 is a schematic diagram of a conventional step-down chopper circuit.
【符号の説明】 １…直流コンデンサ ２…直流リアクトル ３…平滑コンデンサ ４…負荷 ５…第１のスイッチ素子 ６…還流ダイオード ７…保護ヒューズ ８…第２のスイッチ素子 ９…並列回路[Explanation of symbols] 1 ... DC capacitor 2 ... DC reactor 3 ... Smoothing capacitor 4 ... load 5 ... First switch element 6 ... Return diode 7 ... Protective fuse 8 ... Second switch element 9 ... Parallel circuit
Claims (2)
リアクトルと平滑コンデンサよりなる平滑回路を介して
負荷を接続し、且つ、第１のスイッチ素子と直流リアク
トルとの接続点と負荷の負極間に還流ダイオードを逆並
列に接続した第２のスイッチング素子を有するチョッパ
回路において、 前記第１のスイッチング素子と第２のスイッチング素子
の動作を相反してオン，オフ制御させると共に、第２の
スイッチング素子のオン時間を第１のスイッチング素子
のオフ時間より短くし、第１のスイッチング素子のショ
ート事故時に第２のスイッチング素子を介して電流を流
すことを特徴とした降圧チョッパ回路による負荷の過電
圧防止方法 。 1. A first switching element and a direct current for a direct current power supply.
Via a smoothing circuit consisting of a reactor and a smoothing capacitor
Connect the load and connect the first switch element and the DC reactor.
Inverting a freewheeling diode between the connection point with the tor and the negative electrode of the load
Chopper having a second switching element connected in series
In the circuit, the first switching element and the second switching element
The operation of is turned on and off contradictoryly, and the second
ON time of the switching element is the first switching element
Shorter than the off time of the first switching element.
Current through the second switching element
Overload of load by a step-down chopper circuit characterized by
Pressure prevention method .
ューズを設けて構成したことを特徴とした請求項１に記
載の降圧チョッパ回路による負荷の過電圧防止方法。2. The load overvoltage prevention method by a step-down chopper circuit according to claim 1, wherein a protective fuse is provided in series with the first switch element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05432996A JP3475643B2 (en) | 1996-03-12 | 1996-03-12 | Overvoltage prevention method by step-down chopper circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05432996A JP3475643B2 (en) | 1996-03-12 | 1996-03-12 | Overvoltage prevention method by step-down chopper circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09247927A JPH09247927A (en) | 1997-09-19 |
| JP3475643B2 true JP3475643B2 (en) | 2003-12-08 |
Family
ID=12967562
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05432996A Expired - Fee Related JP3475643B2 (en) | 1996-03-12 | 1996-03-12 | Overvoltage prevention method by step-down chopper circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3475643B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19842444A1 (en) * | 1998-09-16 | 2000-03-30 | Siemens Nixdorf Inf Syst | Overvoltage shutdown |
| KR100434148B1 (en) * | 2002-03-05 | 2004-06-04 | 엘지산전 주식회사 | Input over voltage protection of power conversion systems |
| JP5743913B2 (en) * | 2012-01-18 | 2015-07-01 | 三菱電機株式会社 | Power converter |
| JP5958067B2 (en) * | 2012-05-11 | 2016-07-27 | ソニー株式会社 | Power supply device, power supply control method, and electric vehicle |
-
1996
- 1996-03-12 JP JP05432996A patent/JP3475643B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09247927A (en) | 1997-09-19 |
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