JP2005012913A - Power converter - Google Patents

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Publication number
JP2005012913A
JP2005012913A JP2003174202A JP2003174202A JP2005012913A JP 2005012913 A JP2005012913 A JP 2005012913A JP 2003174202 A JP2003174202 A JP 2003174202A JP 2003174202 A JP2003174202 A JP 2003174202A JP 2005012913 A JP2005012913 A JP 2005012913A
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Japan
Prior art keywords
terminal
switching element
semiconductor switching
terminals
protection circuit
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JP2003174202A
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Japanese (ja)
Inventor
Yasuhiko Kono
恭彦 河野
Satoru Horie
哲 堀江
Satoshi Inarida
聡 稲荷田
Katsumi Ishikawa
勝美 石川
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Hitachi Ltd
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Hitachi Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To offer a three-level inverter which prevents the overvoltage breakage of an IGBT at protection from an overcurrent. <P>SOLUTION: For this power converter, regarding the level of an overcurrent at which the overcurrent protection circuit of each semiconductor switching element constituting the arm of a three-level inverter operates, the value of the semiconductor switching element on the side of an AC terminal is larger than the value of the protection circuit of the semiconductor switching element on the side of a DC terminal, or the protection circuit of the semiconductor switching element on the side of a DC terminal operates, being delayed behind the protection circuit of the semiconductor switching element on the side of a DC terminal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、直流電力を入力し、３レベルの電圧を出力する電力変換装置にかかり、特に過電流保護回路を有する電力変換装置に関する。
【０００２】
【従来の技術】
直流を交流に変換するインバータには大きく分けて２レベルインバータと３レベルインバータの２種類がある。３レベルインバータは、２レベルインバータに比べて回路構成は複雑になるが、（１）高調波成分を低減できるためノイズが少ない、（２）モーター駆動時にモータートルクの脈動を小さくできる、（３）モーターの磁歪音が少ない、（４）スイッチング素子の耐圧を低くできる、等の利点があり、広く使われている。
【０００３】
図２に３レベルインバータの回路を示す。図２の符号で、１００１と１００２は直流入力端子、１００３は交流出力端子、１００４と１００５はフィルタコンデンサ、１００６と１００７はクランプダイオード、１００８〜１０１１はゲート駆動回路、１０１２〜１０１５は過電流保護回路、１０１６〜１０１９はＩＧＢＴ、１０２０〜１０２３はフリーホイーリィングダイオード、１０２４〜１０２７は電流検出回路である。
【０００４】
図２の回路動作を簡単に説明する。直流入力端子１００１にプラスの電圧を、直流入力端子１００２には１００１に印加した電圧とは同じ大きさで極牲が逆の直流電圧を印加する。ＩＧＢＴ１０１６とＩＧＢＴ１０１７を導通させて、ＩＧＢＴ１０１８とＩＧＢＴ１０１９を非導通にすると、交流出力端子１００３には直流入力端子１００１の正の電圧が出力される。次にＩＧＢＴ１０１６を非導通にして、ＩＧＢＴ１０１８を導通すると、交流出力端子１００３はクランプダイオード１００６，１００７によりアース電位に固定される。続いてＩＧＢＴｌ０１７を非導通にして１０１９を導通すると交流出力端子１００３には直流入カ端子１００２の負の電圧が出力される。これを繰り返すことにより、正、零、負の３つの電圧レベルを出力できる。
【０００５】
次に図２の過電流保護回路の動作を説明する。ゲート駆動回路の誤動作等により３個以上のＩＧＢＴが同時に導通すると、フィルタコンデンサ１００４、１００５がＩＧＢＴで短絡され、過大な電流が流れる。電流検出回路はＩＧＢＴに流れる電流に対応した大きさの信号を過電流保護回路に出力している。過大な電流が流れてこの信号が予め定められたレベルを超えると過電流保護回路がゲート駆動回路に保護信号を送信し、この信号を受けてゲート駆動回路はＩＧＢＴを非導通にさせて過電流を遮断、あるいはゲート電圧を制限して電流を低減する。この時、過電流保護回路の動作の順番が重要となる。交流出力端子１００３に近いＩＧＢＴ、すなわち１０１７と１０１８を先に遮断すると、ＩＧＢＴ１０１７、１０１８に過電圧が印加されて破壊してしまう。例として、全てのＩＧＢＴが誤動作により導通し過電流が流れており、１０１７を先に遮断した場合を考える。この場合、ＩＧＢＴ１０１６は導通しているのでＩＧＢＴ１０１７のコレクタには直流入力端子１００１の正の電圧が印加され、１０１８と１０１９も導通しているのでＩＧＢＴｌ０１７のエミッタには直流入力端子１００２の負の電圧が印加される。つまり先に遮断されたＩＧＢＴの両端に電源電圧が印加されるという問題が生じる。
【０００６】
この問題を回避するために、下記特許文献１では、短絡保護回路による遮断の順番を制御するロジック回路を設け、交流出力端子１００３に近いＩＧＢＴ、すなわち１０１７、１０１８が後から遮断されるように制御している。
【０００７】
【特許文献１】
特開平１０−６６３４８号公報
【０００８】
【発明が解決しようとする課題】
しかしながら上記特許文献１の回路では、過電流を検出してから検出信号がロジック回路に伝わりそこで遮断の順番を決定してからゲート駆動回路に伝達されるために、過電流を検出してから実際にＩＧＢＴが遮断されるまでに時間遅れが生じる。上述したようなアーム短絡の場合には電流の増加率は５０００〜６０００Ａ／μｓにも達するために、わずかな時間遅れが生じても保護が間に合わなくなる恐れがあった。
【０００９】
また、新たにロジック回路を付加するために、回路が複雑になり、部品点数が増加し、装置が大型化したり、コストが増加したりする問題もあった。
【００１０】
本発明は上記問題点を解決し、過電流保護時のＩＧＢＴの過電圧破壊を防止した３レベルインバータを提供することを目的とする。
【００１１】
【課題を解決するための手段】
本発明の電力変換装置は、一対の直流端子と、該一対の直流端子の電位の中間の電位を有する点と、相数と同数の交流端子と、前記直流端子の高電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した上アームと、前記直流端子の低電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した下アームと、前記アームの前記２個の並列回路の接続点と、前記一対の直流端子の各電位の中間の電位を有する点との間にそれぞれ接続したダイオードと、前記各半導体スイッチング素子を過電流から保護する保護回路とを具備し、保護回路が動作する過電流レベルが、交流端子側半導体スイッチング素子の保護回路の値と、直流端子側半導体スイッチング素子の保護回路の値とで異なる。
【００１２】
本発明の電力変換装置は、前記交流端子側半導体スイッチング素子の保護回路が、直流端子側半導体スイッチング素子の保護回路動作より遅れる。
【００１３】
【発明の実施の形態】
以下、絶縁ゲート型半導体スイッチング素子であるＩＧＢＴを備えた電力変換装置を例にして、本発明の詳細を図面を用いながら説明する。
【００１４】
（実施例１）
図１に本発明による第１の実施例を示す。図１において図２と共通の構成要素には同一の符号を付けてある。図１において、１０３０、１０３１は保護動作する過電流レベルを高く設定した過電流保護回路である。本実施例では、交流出力端子側のＩＧＢＴ１０１７と１０１８（以下これを出力側のＩＧＢＴと呼ぶ）の過電流保護回路１０３０、１０３１の過電流判定レベルを、直流入力端子側のＩＧＢＴ１０１６、１０１９（以下これを入力側のＩＧＢＴと呼ぶ）の過電流保護回路の過電流検出レベルより高く設定した。
【００１５】
この構成によれば、３個以上のＩＧＢＴが同時に導通した場合に、入力側の過電流保護回路１０１２、１０１５が出力側の過電流保護回路１０３０、１０３１よりも先に過電流検出レベルに達するために、入力側の過電流保護回路１０１２、１０１５が先に保護動作を始める。このため、入力側のＩＧＢＴを先に遮断できるので、出力側のＩＧＢＴに電源電圧が印加されない。
【００１６】
また、本実施例では、保護の順番を判定するロジック回路等を経由しないで保護回路から信号が直接ゲート駆動回路に伝達されるために時間遅れが生じず、保護遅れによるＩＧＢＴの破壊を防止できる。
【００１７】
出力側の過電流保護回路の過電流検出レベルＩａと入力側の過電流保護回路の過電流検出レベルＩｂの差ΔＩｓは、通常動作時に出力側のＩＧＢＴに流れる電流の最大値を考慮して設定することが望ましい。このことについて図５を使って説明する。
【００１８】
図５はＩＧＢＴ１０１７とＩＧＢＴ１０１８が導通の状態で、ＩＧＢＴ１０１６が誤動作で導通した場合のＩＧＢＴ１０１７とＩＧＢＴ１０１６の電流波形を示す。図５の符号で、１０６０はＩＧＢＴ１０１７の電流波形、１０６１はＩＧＢＴ１０１６の電流波形である。時刻ｔ１でＩＧＢＴ１０１７が導通し、ＩＧＢＴ１０１７の電流が増加する。増加直後にピークが生じているのはフリーホイーリングダイオードのリカバリー電流が流れるためである。ピークを過ぎると電流は負荷のインダクタンスで決まる電流増加率で増加して行く。
【００１９】
時刻ｔ２でＩＧＢＴ１０１６が導通すると短絡状態となり、電流が急激に増加し始める。電流が時刻ｔ４でＩＧＢＴ１０１６の過電流レベルＩａに達すると保護回路が動作し、若干の時間遅れの後、時刻ｔ５で電流が減少し始める。
【００２０】
ここでＩＧＢＴ１０１７の過電流レベルをＩＧＢＴ１０１６と同じ過電流レベルＩａに設定していると、時刻ｔ３でＩＧＢＴ１０１７の方が先に保護動作が始まり遮断されてしまう。これを防ぐために図５に示すように、ＩＧＢＴ１０１７の過電流レベルＩｂを過電流レベルＩａよりもＩｎ以上大きくしておけば良い。このΔＩｓはインバータの動作状態により変わるＩｎに依存しているために、確実にＩＧＢＴ１０１６を先に遮断するためには、Ｉｎの最大値Ｉｎｍａｘ以上、すなわち、ΔＩｓ＞Ｉｎｍａｘとしてやればよい。実際には、素子の特性のばらつきなどを考慮して、ΔＩｓに更に５％程度のマージンを持って設定するとよい。
【００２１】
（実施例２）
図３に、本実施例を示す。図３において図１乃至図２と同一の構成要素には同じ符号を付けてある。図３の符号、１０４０、１０４１は遅延回路である。本実施例では、過電流保護回路１０１２〜１０１５の過電流検出レベルは全て同じレベルに設定しておき、出力側の保護回路の信号出力に遅延回路１０４０、１０４１を接続した。
【００２２】
この遅延回路の働きを説明する。過電流が流れると、過電流保護回路が過電流を検出しゲート駆動回路にＩＧＢＴの保護の指令を出す。この時、出力側の過電流保護回路の指令信号は遅延回路１０４０、１０４１を経てゲート駆動回路１００９、１０１０に入力されるため、入カ側のゲート駆動回路１００８、１０１１よりも保護動作が遅れる。これにより出力側のＩＧＢＴを入力側のＩＧＢＴよりも後に遮断することができ、出力側のＩＧＢＴが先に遮断されて電源電圧が印加される問題を解決できる。
【００２３】
また、入力側のＩＧＢＴの遮断動作はロジック回路等を通らずに信号が保護回路から直接ゲート駆動回路に到達するために保護動作の遅れが無く、保護遅れによる破壊を防止できる。
【００２４】
（実施例３）
図４に、本実施例を示す。図４において、図１乃至図３と同一の構成要素には同じ符号を付けてある。図４の符号、１０５０、１０５１、１０５２、１０５３はコレクタ電圧検出回路である。本実施例では、過電流保護回路が、過電流通電時のコレクタ電圧の増加を検出して、過電流保護の判定をする。
【００２５】
本実施例では出力側の過電流保護回路の過電流判定レベルを、入力側の過電流保護回路の過電流検出レベルより高く設定してあるので、出力側のＩＧＢＴが先に遮断されて電源電圧が印加される問題を解決できる。この時、過電流検出レベルの差は実施例１と同様に、通常状態で出力側のＩＧＢＴを通して負荷に流れる電流の最大値以上に設定することが望ましい。
【００２６】
以上、本発明の実施例をＩＧＢＴを使って説明してきたが、半導体スイッチング素子はＩＧＢＴに限定されるものではなく、パワーＭＯＳＦＥＴやＧＴＯなどの半導体電力スイッチング素子を使っても同様である。
【００２７】
【発明の効果】
以上説明したように、本発明によれば３レベルインバータの過電流の保護時に出力側のＩＧＢＴに電源電圧が印加されないので、高い信頼性の電力変換装置が実現できる。
【図面の簡単な説明】
【図１】本発明の第１の実施例の回路の説明図である。
【図２】従来技術の回路の説明図である。
【図３】本発明の第２の実施例の回路の説明図である。
【図４】本発明の第３の実施例の回路の説明図である。
【図５】本発明の第１の実施例の動作波形である。
【符号の説明】
１００１，１００２…直流入力端子、１００３…交流出力端子、１００４，１００５…フィルタコンデンサ、１００６，１００７…クランプダイオード、１００８〜１０１１…駆動回路、１０１２〜１０１５…過電流保護回路、１０１６〜１０１９…ＩＧＢＴ、１０２０〜１０２３…フリーホイーリングダイオード、１０２４〜１０２７…電流検出回路、１０３０，１０３１…過電流保護回路、１０４０，１０４１…遅延回路、１０５０〜１０５３…電圧検出回路、１０６０…ＩＧＢＴ１０１７の電流波形、１０６１…ＩＧＢＴ１０１６の電流波形。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power converter that inputs DC power and outputs a three-level voltage, and more particularly to a power converter that has an overcurrent protection circuit.
[0002]
[Prior art]
There are roughly two types of inverters that convert direct current into alternating current: two-level inverters and three-level inverters. The circuit configuration of the 3-level inverter is more complicated than that of the 2-level inverter, but (1) less noise because harmonic components can be reduced, (2) motor torque pulsation can be reduced when the motor is driven, (3) There are advantages such as low magnetostriction noise of the motor, and (4) low withstand voltage of the switching element, which are widely used.
[0003]
FIG. 2 shows a circuit of a three-level inverter. 2, 1001 and 1002 are DC input terminals, 1003 is an AC output terminal, 1004 and 1005 are filter capacitors, 1006 and 1007 are clamp diodes, 1008 to 1011 are gate drive circuits, and 1012 to 1015 are overcurrent protection circuits. Reference numerals 1016 to 1019 denote IGBTs, 1020 to 1023 denote free wheeling diodes, and 1024 to 1027 denote current detection circuits.
[0004]
The circuit operation of FIG. 2 will be briefly described. A positive voltage is applied to the DC input terminal 1001 and a DC voltage having the same magnitude as that of the voltage applied to the DC input terminal 1002 but having the opposite polarity is applied to the DC input terminal 1002. When the IGBT 1016 and the IGBT 1017 are made conductive and the IGBT 1018 and the IGBT 1019 are made non-conductive, the positive voltage of the DC input terminal 1001 is output to the AC output terminal 1003. Next, when the IGBT 1016 is turned off and the IGBT 1018 is turned on, the AC output terminal 1003 is fixed to the ground potential by the clamp diodes 1006 and 1007. Subsequently, when IGBT1017 is turned off and 1019 is turned on, the negative voltage of the DC input terminal 1002 is output to the AC output terminal 1003. By repeating this, three voltage levels of positive, zero, and negative can be output.
[0005]
Next, the operation of the overcurrent protection circuit of FIG. 2 will be described. When three or more IGBTs are turned on simultaneously due to malfunction of the gate drive circuit or the like, the filter capacitors 1004 and 1005 are short-circuited by the IGBTs, and an excessive current flows. The current detection circuit outputs a signal having a magnitude corresponding to the current flowing through the IGBT to the overcurrent protection circuit. When an excessive current flows and this signal exceeds a predetermined level, the overcurrent protection circuit sends a protection signal to the gate drive circuit. Upon receipt of this signal, the gate drive circuit makes the IGBT non-conductive to overcurrent. Or reduce the current by limiting the gate voltage. At this time, the order of operation of the overcurrent protection circuit is important. If the IGBTs close to the AC output terminal 1003, that is, 1017 and 1018 are shut off first, an overvoltage is applied to the IGBTs 1017 and 1018, causing destruction. As an example, consider the case where all IGBTs are turned on due to malfunction and overcurrent flows, and 1017 is cut off first. In this case, since the IGBT 1016 is conducting, the positive voltage of the DC input terminal 1001 is applied to the collector of the IGBT 1017, and 1018 and 1019 are also conducting, so the negative voltage of the DC input terminal 1002 is applied to the emitter of the IGBT 1017. Applied. That is, there arises a problem that the power supply voltage is applied to both ends of the IGBT that has been cut off first.
[0006]
In order to avoid this problem, in Patent Document 1 below, a logic circuit that controls the order of interruption by the short-circuit protection circuit is provided, and control is performed so that the IGBTs close to the AC output terminal 1003, that is, 1017 and 1018 are later interrupted. is doing.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-66348
[Problems to be solved by the invention]
However, in the circuit of Patent Document 1, since the detection signal is transmitted to the logic circuit after the overcurrent is detected, and the order of interruption is determined there and then transmitted to the gate drive circuit, it is actually detected after the overcurrent is detected. There is a time delay before the IGBT is shut off. In the case of the arm short circuit as described above, the increase rate of the current reaches 5000 to 6000 A / μs, so that there is a possibility that the protection may not be in time even if a slight time delay occurs.
[0009]
In addition, since a new logic circuit is added, there is a problem that the circuit becomes complicated, the number of parts increases, the apparatus becomes larger, and the cost increases.
[0010]
An object of the present invention is to solve the above-described problems and to provide a three-level inverter that prevents overvoltage breakdown of an IGBT during overcurrent protection.
[0011]
[Means for Solving the Problems]
The power conversion device of the present invention includes a pair of DC terminals, a point having an intermediate potential between the potentials of the pair of DC terminals, an AC terminal having the same number of phases, a high potential side of the DC terminal, and an AC terminal. Between the upper arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series, and between the low potential side of the DC terminal and the AC terminal, A diode connected between a lower arm in which two parallel circuits are connected in series, a connection point between the two parallel circuits of the arm, and a point having an intermediate potential between the potentials of the pair of DC terminals And a protection circuit that protects each of the semiconductor switching elements from overcurrent, and the overcurrent level at which the protection circuit operates depends on the value of the protection circuit of the AC terminal side semiconductor switching element and the DC terminal side semiconductor switch. Different between the value of the protection circuit of quenching elements.
[0012]
In the power conversion device of the present invention, the protection circuit for the AC terminal side semiconductor switching element is delayed from the operation of the protection circuit for the DC terminal side semiconductor switching element.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the details of the present invention will be described with reference to the drawings, taking as an example a power conversion device including an IGBT which is an insulated gate semiconductor switching element.
[0014]
(Example 1)
FIG. 1 shows a first embodiment according to the present invention. In FIG. 1, the same components as those in FIG. In FIG. 1, reference numerals 1030 and 1031 denote overcurrent protection circuits in which the overcurrent level at which the protection operation is performed is set high. In this embodiment, the overcurrent determination levels of the overcurrent protection circuits 1030 and 1031 of the IGBTs 1017 and 1018 (hereinafter referred to as output side IGBTs) on the AC output terminal side are set as the IGBTs 1016 and 1019 on the DC input terminal side (hereinafter referred to as this). Is called higher than the overcurrent detection level of the overcurrent protection circuit of the input side IGBT).
[0015]
According to this configuration, when three or more IGBTs are turned on simultaneously, the overcurrent protection circuits 1012 and 1015 on the input side reach the overcurrent detection level before the overcurrent protection circuits 1030 and 1031 on the output side. In addition, the overcurrent protection circuits 1012, 1015 on the input side first start the protection operation. For this reason, since the input-side IGBT can be shut off first, the power supply voltage is not applied to the output-side IGBT.
[0016]
Further, in this embodiment, since a signal is directly transmitted from the protection circuit to the gate drive circuit without going through a logic circuit or the like for determining the order of protection, there is no time delay, and the destruction of the IGBT due to the protection delay can be prevented. .
[0017]
The difference ΔIs between the overcurrent detection level Ia of the output-side overcurrent protection circuit and the overcurrent detection level Ib of the input-side overcurrent protection circuit is set in consideration of the maximum value of the current flowing through the output-side IGBT during normal operation. It is desirable to do. This will be described with reference to FIG.
[0018]
FIG. 5 shows current waveforms of the IGBT 1017 and the IGBT 1016 when the IGBT 1017 and the IGBT 1018 are in a conducting state and the IGBT 1016 is conducted due to a malfunction. In FIG. 5, 1060 is a current waveform of the IGBT 1017, and 1061 is a current waveform of the IGBT 1016. The IGBT 1017 conducts at time t1, and the current of the IGBT 1017 increases. The peak occurs immediately after the increase because the recovery current of the freewheeling diode flows. After the peak, the current increases at a current increase rate determined by the inductance of the load.
[0019]
When IGBT 1016 becomes conductive at time t2, a short-circuit state occurs and the current starts to increase rapidly. When the current reaches the overcurrent level Ia of the IGBT 1016 at time t4, the protection circuit operates, and after a slight time delay, the current starts to decrease at time t5.
[0020]
Here, if the overcurrent level of the IGBT 1017 is set to the same overcurrent level Ia as that of the IGBT 1016, the protection operation of the IGBT 1017 starts earlier and is cut off at time t3. In order to prevent this, as shown in FIG. 5, the overcurrent level Ib of the IGBT 1017 may be set larger than In by over the overcurrent level Ia. Since this ΔIs depends on In which changes depending on the operation state of the inverter, in order to reliably shut off the IGBT 1016 first, it is sufficient to set the value to the In maximum value Inmax or more, that is, ΔIs> Inmax. In practice, it is preferable to set ΔIs with a margin of about 5% in consideration of variations in element characteristics.
[0021]
(Example 2)
FIG. 3 shows this embodiment. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. Reference numerals 1040 and 1041 in FIG. 3 denote delay circuits. In this embodiment, the overcurrent detection levels of the overcurrent protection circuits 1012 to 1015 are all set to the same level, and the delay circuits 1040 and 1041 are connected to the signal output of the protection circuit on the output side.
[0022]
The operation of this delay circuit will be described. When an overcurrent flows, the overcurrent protection circuit detects the overcurrent and issues an IGBT protection command to the gate drive circuit. At this time, since the command signal of the output-side overcurrent protection circuit is input to the gate drive circuits 1009 and 1010 via the delay circuits 1040 and 1041, the protection operation is delayed as compared with the input-side gate drive circuits 1008 and 1011. As a result, the output-side IGBT can be shut off after the input-side IGBT, and the problem that the output-side IGBT is shut off first and the power supply voltage is applied can be solved.
[0023]
In addition, since the input-side IGBT is cut off without passing through the logic circuit or the like, the signal reaches the gate drive circuit directly from the protection circuit, so that there is no delay in the protection operation and destruction due to the protection delay can be prevented.
[0024]
Example 3
FIG. 4 shows this embodiment. 4, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals. Reference numerals 1050, 1051, 1052, and 1053 in FIG. 4 denote collector voltage detection circuits. In this embodiment, the overcurrent protection circuit detects an increase in the collector voltage when energizing the overcurrent, and determines overcurrent protection.
[0025]
In this embodiment, since the overcurrent determination level of the output-side overcurrent protection circuit is set higher than the overcurrent detection level of the input-side overcurrent protection circuit, the output-side IGBT is shut off first and the power supply voltage The problem that is applied can be solved. At this time, as in the first embodiment, the difference in the overcurrent detection level is preferably set to be equal to or greater than the maximum value of the current flowing through the load-side IGBT in the normal state.
[0026]
As described above, the embodiments of the present invention have been described using the IGBT. However, the semiconductor switching element is not limited to the IGBT, and the same applies even if a semiconductor power switching element such as a power MOSFET or GTO is used.
[0027]
【The invention's effect】
As described above, according to the present invention, since the power supply voltage is not applied to the IGBT on the output side when the overcurrent of the three-level inverter is protected, a highly reliable power conversion device can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a circuit according to a first embodiment of this invention.
FIG. 2 is an explanatory diagram of a conventional circuit.
FIG. 3 is an explanatory diagram of a circuit according to a second embodiment of this invention.
FIG. 4 is an explanatory diagram of a circuit according to a third embodiment of the present invention.
FIG. 5 is an operation waveform of the first embodiment of the present invention.
[Explanation of symbols]
1001, 1002 ... DC input terminal, 1003 ... AC output terminal, 1004, 1005 ... Filter capacitor, 1006, 1007 ... Clamp diode, 1008-1011 ... Drive circuit, 1012-1015 ... Overcurrent protection circuit, 1016-1019 ... IGBT, 1020 to 1023 ... freewheeling diode, 1024 to 1027 ... current detection circuit, 1030, 1031 ... overcurrent protection circuit, 1040, 1041 ... delay circuit, 1050 to 1053 ... voltage detection circuit, 1060 ... current waveform of IGBT 1017, 1061 ... The current waveform of IGBT1016.

Claims (8)

一対の直流端子と、
該一対の直流端子の電位の中間の電位を有する点と、
相数と同数の交流端子と、
前記直流端子の高電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した上アームと、
前記直流端子の低電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した下アームと、
前記アームの前記２個の並列回路の接続点と、前記一対の直流端子の各電位の中間の電位を有する点との間にそれぞれ接続したダイオードと、
前記各半導体スイッチング素子の予め定められた電流値以上の主電流を抑制又は遮断する保護回路とを具備し、
前記交流端子に接続された半導体スイッチング素子の保護回路の予め定められた第１の電流値が、前記直流端子に接続された半導体スイッチング素子の保護回路の予め定められた第２の電流値よりも高いことを特徴とする電力変換装置。A pair of DC terminals;
A point having an intermediate potential between the pair of DC terminals;
AC terminals of the same number as the number of phases,
An upper arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the high potential side of the DC terminal and the AC terminal;
A lower arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the low potential side of the DC terminal and the AC terminal;
A diode connected between a connection point of the two parallel circuits of the arm and a point having an intermediate potential between the potentials of the pair of DC terminals;
A protection circuit that suppresses or cuts off a main current equal to or higher than a predetermined current value of each semiconductor switching element;
The predetermined first current value of the protection circuit for the semiconductor switching element connected to the AC terminal is greater than the predetermined second current value of the protection circuit for the semiconductor switching element connected to the DC terminal. A power converter characterized by being expensive. 請求項１に記載の電力変換装置において、前記予め定められた第１の電流値と第２の電流値との差が、電力変換装置の正常動作時に前記交流端子から出力される最大の電流値より大きいことを特徴とする電力変換装置。2. The power conversion device according to claim 1, wherein the difference between the predetermined first current value and the second current value is a maximum current value output from the AC terminal during normal operation of the power conversion device. A power converter characterized by being larger. 一対の直流端子と、
該一対の直流端子の各電位の中間の電位を有する点と、
相数と同数の交流端子と、
前記直流端子の高電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した上アームと、
前記直流端子の低電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した下アームと、
前記アームの前記２個の並列回路の接続点と、前記一対の直流端子の各電位の中間の電位を有する点との間にそれぞれ接続したダイオードと、
前記半導体スイッチング素子の駆動回路と、
前記半導体スイッチング素子の電流を検出し信号を出力する検出回路と、
該検出回路の信号が予め定められた値以上になった場合に前記駆動回路に前記半導体スイッチング素子の電流を制限もしくは遮断する信号を出す過電流保護回路とを具備し、
前記交流端子に接続された半導体スイッチング素子の過電流保護回路で予め定められた第１の値が、前記直流端子に接続された半導体スイッチング素子の過電流保護回路で予め定められた第２の値よりも大きいことを特徴とする電力変換装置。A pair of DC terminals;
A point having an intermediate potential between the potentials of the pair of DC terminals;
AC terminals of the same number as the number of phases,
An upper arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the high potential side of the DC terminal and the AC terminal;
A lower arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the low potential side of the DC terminal and the AC terminal;
A diode connected between a connection point of the two parallel circuits of the arm and a point having an intermediate potential between the potentials of the pair of DC terminals;
A driving circuit for the semiconductor switching element;
A detection circuit for detecting a current of the semiconductor switching element and outputting a signal;
An overcurrent protection circuit that outputs a signal to limit or cut off the current of the semiconductor switching element to the drive circuit when the signal of the detection circuit exceeds a predetermined value;
The first value predetermined in the overcurrent protection circuit of the semiconductor switching element connected to the AC terminal is the second value predetermined in the overcurrent protection circuit of the semiconductor switching element connected to the DC terminal. The power converter characterized by being larger than. 請求項３に記載の電力変換装置において、前記予め定められた第１の値と第２の値との差が、電力変換装置の正常動作時に前記交流端子から出力される最大の電流値より大きいことを特徴とする電力変換装置。4. The power conversion device according to claim 3, wherein a difference between the predetermined first value and the second value is larger than a maximum current value output from the AC terminal during normal operation of the power conversion device. The power converter characterized by the above-mentioned. 一対の直流端子と、
該一対の直流端子の各電位の中間の電位を有する点と、
相数と同数の交流端子と、
前記直流端子の高電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した上アームと、
前記直流端子の低電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した下アームと、
前記アームの前記２個の並列回路の接続点と、前記一対の直流端子の各電位の中間の電位を有する点との間にそれぞれ接続したダイオードと、
前記半導体スイッチング素子の駆動回路と、
前記半導体スイッチング素子の両端の電圧を検出し信号を出力する検出回路と、
前記検出回路の信号が予め定められた値以上になった場合に、前記駆動回路に前記半導体スイッチング素子の電流を制限もしくは遮断する信号を出す過電流保護回路とを具備し、
前記交流端子に接続された半導体スイッチング素子の過電流保護回路の予め定められた第１の値が、前記直流端子に接続された半導体スイッチング素子の過電流保護回路の予め定められた第２の値よりも大きいことを特徴とする電力変換装置。A pair of DC terminals;
A point having an intermediate potential between the potentials of the pair of DC terminals;
AC terminals of the same number as the number of phases,
An upper arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the high potential side of the DC terminal and the AC terminal;
A lower arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the low potential side of the DC terminal and the AC terminal;
A diode connected between a connection point of the two parallel circuits of the arm and a point having an intermediate potential between the potentials of the pair of DC terminals;
A driving circuit for the semiconductor switching element;
A detection circuit for detecting a voltage across the semiconductor switching element and outputting a signal;
An overcurrent protection circuit that outputs a signal to limit or cut off the current of the semiconductor switching element to the drive circuit when the signal of the detection circuit is equal to or higher than a predetermined value;
The first predetermined value of the overcurrent protection circuit of the semiconductor switching element connected to the AC terminal is the second predetermined value of the overcurrent protection circuit of the semiconductor switching element connected to the DC terminal. The power converter characterized by being larger than. 請求項５に記載の電力変換装置において、前記予め定められた第１の値と第２の値との差が、電力変換装置の正常動作時に前記交流端子から出力される最大の電流値より大きいことを特徴とする電力変換装置。6. The power conversion device according to claim 5, wherein a difference between the predetermined first value and the second value is greater than a maximum current value output from the AC terminal during normal operation of the power conversion device. The power converter characterized by the above-mentioned. 一対の直流端子と、
該一対の直流端子の各電位の中間の電位を有する点と、
相数と同数の交流端子と、
前記直流端子の高電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した上アームと、
前記直流端子の低電位側と交流端子との間に、半導体スイッチング素子と逆極性のダイオードとの並列回路を２個直列接続した下アームと、
前記アームの前記２個の並列回路の接続点と、前記一対の直流端子の各電位の中間の電位を有する点との間にそれぞれ接続したダイオードと、
前記半導体スイッチング素子の予め定められた電流値以上の電流を抑制又は遮断する保護回路を具備し、
前記交流端子に接続された半導体スイッチング素子の保護回路が遅延回路を備えていて、前記直流端子に接続された半導体スイッチング素子の保護回路より遅れて保護動作することを特徴とする電力変換装置。A pair of DC terminals;
A point having an intermediate potential between the potentials of the pair of DC terminals;
AC terminals of the same number as the number of phases,
An upper arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the high potential side of the DC terminal and the AC terminal;
A lower arm in which two parallel circuits of a semiconductor switching element and a diode of reverse polarity are connected in series between the low potential side of the DC terminal and the AC terminal;
A diode connected between a connection point of the two parallel circuits of the arm and a point having an intermediate potential between the potentials of the pair of DC terminals;
Comprising a protection circuit that suppresses or cuts off a current equal to or higher than a predetermined current value of the semiconductor switching element;
The power conversion device according to claim 1, wherein the protection circuit for the semiconductor switching element connected to the AC terminal includes a delay circuit, and performs a protection operation later than the protection circuit for the semiconductor switching element connected to the DC terminal. 請求項１から請求項７の何れか１項に記載の電力変換装置において、前記半導体スイッチング素子が絶縁ゲート型半導体スイッチング素子であることを特徴とする電力変換装置。The power conversion device according to any one of claims 1 to 7, wherein the semiconductor switching element is an insulated gate semiconductor switching element.
JP2003174202A 2003-06-19 2003-06-19 Power converter Withdrawn JP2005012913A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101860252A (en) * 2010-04-28 2010-10-13 清华大学 Three-level converter for optimizing device overcurrent protection and enlarging system safety operation area
WO2012122825A1 (en) * 2011-03-16 2012-09-20 中国电力科学研究院 Modular multilevel converter valve protection method
CN102868290A (en) * 2012-09-05 2013-01-09 华北电力大学 Total bridge type MMC (Microsoft Management Console)-HVDC (High Voltage Direct Current Transmission) sub-module fault in-situ diagnosing and protecting method
CN105471308A (en) * 2014-09-30 2016-04-06 株式会社日立制作所 Power converter protector and protection method thereof
WO2024047710A1 (en) * 2022-08-29 2024-03-07 東芝三菱電機産業システム株式会社 Electric power conversion control device, electric power conversion device, and protection method

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101860252A (en) * 2010-04-28 2010-10-13 清华大学 Three-level converter for optimizing device overcurrent protection and enlarging system safety operation area
WO2012122825A1 (en) * 2011-03-16 2012-09-20 中国电力科学研究院 Modular multilevel converter valve protection method
CN102868290A (en) * 2012-09-05 2013-01-09 华北电力大学 Total bridge type MMC (Microsoft Management Console)-HVDC (High Voltage Direct Current Transmission) sub-module fault in-situ diagnosing and protecting method
CN102868290B (en) * 2012-09-05 2015-04-15 华北电力大学 Total bridge type MMC (Microsoft Management Console)-HVDC (High Voltage Direct Current Transmission) sub-module fault in-situ diagnosing and protecting method
CN105471308A (en) * 2014-09-30 2016-04-06 株式会社日立制作所 Power converter protector and protection method thereof
CN105471308B (en) * 2014-09-30 2018-07-06 株式会社日立制作所 The protective device of power-converting device and guard method
WO2024047710A1 (en) * 2022-08-29 2024-03-07 東芝三菱電機産業システム株式会社 Electric power conversion control device, electric power conversion device, and protection method

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