JP2004166437A - Current balance control circuit for power supply device - Google Patents

Current balance control circuit for power supply device Download PDF

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JP2004166437A
JP2004166437A JP2002331584A JP2002331584A JP2004166437A JP 2004166437 A JP2004166437 A JP 2004166437A JP 2002331584 A JP2002331584 A JP 2002331584A JP 2002331584 A JP2002331584 A JP 2002331584A JP 2004166437 A JP2004166437 A JP 2004166437A
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current
circuit
power supply
voltage
supply device
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JP3897251B2 (en
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Takehiro Koizumi
雄大 小泉
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Cosel Co Ltd
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Cosel Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To prevent, even if some of power supply devices which are connected in parallel with a load and redundantly operated become faulty, the output voltage drop from occurring in normal power supply devices. <P>SOLUTION: When a power supply device 1B becomes faulty and current detection value Vi2 becomes 0V, the divided voltage of resistors R4 and R5 also becomes 0V, thereby a transistor Tr2 connected in series with a constant-current circuit 6 is turned off, so that the constant-current circuit is isolated from a current balance control circuit 10B, to prevent the passage of unbalanced current i. Therefore, bias voltage +vi produced in a resistor R0 in a normal power supply device 1A is set equal to that before the fault, and the output voltage of the normal power supply device with respect to the load is prevented from being lowered. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明の属する技術分野】
本発明は、複数の電源装置の出力側を負荷に並列接続して並列電流バランスをとる電源装置の電流バランス制御回路に関する。
【0002】
【従来の技術】
従来、複数の電源装置を負荷に並列接続して冗長運転する際に使用する電流バランス制御回路としては、例えば図3に示すようなものがある(特許文献1)。
【0003】
図3において、1A,1Bは電源装置であり、負荷2がダイオードD3,D4を介して並列接続されている。電源装置1A,1Bから負荷2に対して同じ値の電流I1,I2を供給する。
電源装置1A,1Bには出力制御回路3が設けられ、スイッチング制御により一定電圧に安定化された出力電圧V0が負荷2に供給される。出力電圧V0は抵抗R1とR2で分圧されて増幅器4の(−)入力端子に与えられ、(+)入力端子にはツェナーダイオードZDのツェナー電圧により予め定めた基準電圧を固定的に設定する。
【0004】
増幅器4は、出力電圧V0を抵抗R1とR2で分圧した電圧にバイアス電圧発生用の抵抗R0で発生した電圧+Viを加えた電圧と、ツェナーダイオードZDの基準電圧との差電圧に応じて増幅したある電圧を出力制御回路3に出力し、出力制御回路3の出力電圧V0が一定となるように制御する。
【0005】
一方、電源装置1A,1Bには、電流バランス制御回路10A,10Bが設けられる。電流バランス制御回路10A,10Bには、負荷2に供給する出力電流I1,I2を検出するカレントトランス5が設けられ、カレントトランス5の出力はダイオードD0により整流されてコンデンサC0に検出電圧Vi1,Vi2として充電される。またコンデンサC0には電流−電圧変換用の抵抗R3が並列接続される。
【0006】
この電流バランス制御回路10A,10Bのそれぞれに設けたカレントトランス5、ダイオードD0、コンデンサC0および抵抗R3でなる電流検出回路には、抵抗R0を介して定電流回路6が接続され、更に定電流回路6の出力側で相互接続される。
【0007】
次に、図3の動作を説明する。電源装置1A,1Bから負荷2に流れる電流が等しいバランス状態では、電流バランス制御回路10A,10Bの電流検出電圧Vi1、Vi2が等しい。このため電流バランス制御回路10Aでは、電流検出電圧Vi1を電圧源としてコンデンサC0のプラス側から抵抗R0、定電流回路6、ダイオードD1を経てコンデンサC0のマイナス側に定電流Ic1が流れる。
【0008】
また電流バランス制御回路10Bでは、電流検出電圧Vi2を電圧源としてコンデンサC0のプラス側から抵抗R0、定電流回路6、ダイオードD2を経てコンデンサC0のマイナス側に定電流Ic2流れる。このため電流バランス制御回路10A,10Bの間に不平衡電流iは流れない。ここで定電流Ic1、Ic2は同じ電流値であり、例えば1mAとなる。
【0009】
これにより電流バランス制御回路10A,10Bの抵抗R0に発生するバイアス電圧+Viは等しく、増幅器4の入力電圧も等しく、増幅器4は出力制御回路3を出力電圧V0が等しくなるように制御し、負荷2に対する出力電流I1,I2はバランスしている。
【0010】
この出力電圧V0を一定値にする安定制御状態において、電源装置1Aの出力電流I1が電源装置1Bの出力電流I2より大きくなる電流バランスの崩れを生じたとする。このI1>I2となる電流バランスの崩れに対し、電源装置1Aの出力電流I1に応じて電流バランス制御回路10Aの電流検出電圧Vi1が増加し、また電源装置1Bの出力電流I2に応じて電流バランス制御回路10Bの電流検出電圧Vi2は低下し、Vi1>Vi2となる。
【0011】
このため電流バランス制御回路10A,10B間には、電源装置1Aから1Bに向けて不平衡電流iが電流検出電圧の差に応じて流れる。例えば不平衡電流iとして0.2mA流れたとすると、電流バランス制御回路10Aでは抵抗R0に定電流回路6の定電流Ic1=1mAに不平衡電流i=0.2mAを加えた1.2mAの電流が流れ、バイアス電圧+Viが増加する。
【0012】
一方、電流バランス制御回路10Bでは、不平衡電流i=0.2mAが流れ込むことで、抵抗R0には定電流回路6の定電流Ic1=1mAから不平衡電流i=0.2mAを差し引いた0.8mAの電流が流れ、バイアス電圧+Viが減少する。
【0013】
電流バランス制御回路10Aにおいてバイアス+Viが増加すると、増幅器4の出力は低下し、出力制御回路3の出力電圧を下げて電源装置1Aからの出力電流I1を減少させる。一方、電流バランス制御回路10Bにおいてバイアス+Viが減少すると、増幅器4の出力は増加し、出力制御回路3の出力電圧を上げて電源装置1Bからの出力電流I1を増加させ、最終的に出力電流I1=I2、ずなわち不平衡電流i=0となる電流バランスの保持状態を保つようになる。
【0014】
【特許文献1】
特開平9−288518号公報
【0015】
【発明が解決しようとする課題】
しかしながら、このような従来の電源装置の電流バランス制御回路にあっては、片側の電源装置が故障して電流検出電圧が断たれた場合、正常な電源装置の出力電圧が低下してしまうという問題がある。
【0016】
例えば片方の電源装置1Bが故障して、電流バランス制御回路10Bの電流検出電圧Vi2が0Vになった場合には、ダイオードD2によって抵抗R0、R3に流れる電流は阻止されるが、定電流回路6の定電流Ic2に一致する不平衡電流iが電源装置1Aの電流バランス制御回路10Aから故障した電源装置1Bの電流バランス制御回路10Bに流れる。
【0017】
このため正常な電源装置1Aの電流バランス制御回路10Aに設けた抵抗R0に両方の定電流回路6に流れる定電流を加算した電流(Ic1+Ic2)が流れ、バイアス電圧+Viがほぼ2倍に増加する。
【0018】
このため増幅器4の出力が低下し、出力制御回路3は出力電圧V0を下げるように制御され、正常な電源装置1Aから負荷2に対する出力電圧が低下する。
【0019】
この問題に対し従来は、片方の電源装置の故障で生ずる出力電圧の低下を、電源装置の仕様上無視できる範囲に抑えるように抵抗R0の値や定電流回路6の定電流を決めることで対応している。
【0020】
しかし、片側の電源装置の故障により負荷に対する出力電圧が低下することは、例え出力電圧の低下が装置の仕様を損なわない範囲であったとしても、複数の電源装置を負荷に並列接続して故障が起きても安定化した電源供給を維持するという冗長運転本来の意図が損なわれており、この点の改善が望まれる。
【0021】
本発明は、負荷に並列接続して冗長運転している複数の電源装置の一部に故障が起きても、正常な電源装置に出力電圧の低下が起きないようにした電源装置の電流バランス制御回路を提供することを目的とする。
【0022】
【課題を解決するための手段】
この目的を達成するため本発明は次のように構成する。
【0023】
本発明は、冗長運転のために複数の電源装置を負荷に並列接続し、複数の電源装置から負荷に流れる電流が一致するように制御する他の電源装置の電流バランス回路と相互に接続された電源装置の電流バランス制御回路を対象とする。
【0024】
この電流バランス制御回路は、負荷に流れる電流に比例した電圧を発生し、他の電源装置の電流検出回路と相互接続される電流検出回路と、電流検出回路に対する電流の逆流を阻止するダイオードと、電流検出回路に接続され一定電流を流す定電流回路と、電流検出回路と定電流回路を結ぶプラス側信号ラインに挿入接続されるバイアス電圧発生回路とを備える。
【0025】
このバイアス電圧発生回路は、
a)電流検出回路と他の電源装置の電流検出回路との間に電圧差がない時は、定電流回路に流す一定電流に応じたバイアス電圧を発生し、
b)電流検出電圧源の検出電圧が他の電源装置の電流検出回路に対しプラスの電圧差を持つ時は、定電流回路に流す一定電流に他の電源装置に流れ出す不平衡電流を加えた電流に応じたバイアス電圧を発生し、更に、
c)電流検出回路の検出電圧が他の電源装置の電流検出回路に対しマイナスの電圧差を持つ時は、定電流回路に流す一定電流から他の電源装置から流れ込む不平衡電流を差し引いた電流に応じたバイアス電圧を発生し、
d)各バイアス電圧を前記増幅器に対する出力電圧に加算して負荷に流れる電流が他の電源装置から負荷に流れる電流に一致するように差電圧を変化させる。
【0026】
これに加え本発明の電流バランス制御回路にあっては、電流検出回路の発生電圧が失われる故障を検出した時に、定電流回路を切り離して他の電源装置からの不平衡電流の流れ込みを阻止する故障切離し回路を設けたことを特徴とする。
【0027】
このため例えば2台の電源装置を負荷に並列接続して冗長運転している際に、片側の電源装置が故障して負荷電流が断たれた場合、故障を起こした電源装置の電流バランス制御回路に設けている電流検出回路の発生電圧が失われ、これを故障切離し回路で検出して定電流回路を切離すことで正常な電源装置の電流バランス回路からの不平衡電流の流れ込みを阻止し、正常な電流バランス制御回路の抵抗に発生するバイアス電圧を、複数の電源装置の出力電流がバランスした安定制御状態の電圧に保つ。このため片側の電源装置が故障しても、残された正常な電源装置の負荷に対する出力電圧は低下せずに一定電圧に制御され、安定した冗長運転を継続することができる。
【0028】
ここで、故障切離し回路は、定電流回路に直列接続されたトランジスタと、電流検出回路の発生電圧を分圧してトランジスタのベースにバイアス電圧を印加し、電流検出回路の発生電圧が断たれる故障検出時にトランジスタをオフして定電流回路を切離すバイアス回路とを備える。
【0029】
また故障切離し回路は、定電流回路に直列接続された電界効果トランジスタと、電流検出回路の発生電圧を分圧して電界効果トランジスタのゲートにバイアス電圧を印加し、電流検出回路の発生電圧が断たれる故障検出時に電界効果トランジスタをオフして定電流回路を切離すバイアス回路とを備えるようにしても良い。
【0030】
【発明の実施の形態】
図1は本発明による電源装置の電流バランス制御回路の実施形態を冗長運転のための接続状態ついて示した回路図である。
【0031】
図1において、電源装置1A,1Bは、冗長運転による電源供給のため、ダイオードD3,D4を介して負荷2に並列接続され、電源装置1A,1Bから負荷2に対して同じ値の電流I1,I2を供給するよう出力制御回路3により出力電圧V0を制御させる電流バランス制御回路10A,10Bを設けている。
【0032】
電源装置1A,1Bに設けた出力制御回路3はスイッチングレギュレータで構成され、例えばDC−DCコンバータ、整流出力回路、制御回路を備え、DC−DCコンバータに設けたトランスの1次巻線に接続したスイッチ素子のオン,オフ制御により負荷2に供給する出力電圧V0を一定電圧に安定化制御する。
【0033】
出力電圧V0は抵抗R1とR2で分圧されて増幅器4の(−)入力端子に与えられ、(+)入力端子にはツェナーダイオードZDのツェナー電圧により予め定めた基準電圧を固定的に設定する。
【0034】
増幅器4は、出力電圧V0を抵抗R1、R2で分圧した電圧に、電流バランス制御回路10A,10Bの抵抗R0で発生したバイアス電圧+Viを加えた電圧を入力し、ツェナーダイオードZDの基準電圧との差に応じて増幅した差電圧を出力制御回路3に出力し、出力制御回路3の出力電圧V0が一定電圧となるように制御する。
【0035】
電源装置1A,1Bに設けた電流バランス制御回路10A,10Bには、負荷2に供給する出力電流I1,I2を検出するカレントトランス5が設けられる。カレントトランス5は出力制御回路3に設けているDC−DCコンバータの1次側のスイッチ素子のオン、オフ制御による電流を1次巻線に流し、2次側に上向き矢印方向の電圧を発生する。
【0036】
カレントトランス5の出力はダイオードD0により整流されてコンデンサC0に電流検出電圧Vi1,Vi2として充電される。またコンデンサC0には電流−電圧変換用の抵抗R3が並列接続され、検出電流に比例した電圧を発生する電圧源として機能する。
【0037】
この電流バランス制御回路10A,10Bに設けたカレントトランス5、ダイオードD0、コンデンサC0及び抵抗R3でなる電流検出回路には、抵抗R0を介して定電流回路6が接続され、更に定電流回路6の出力側で電流バランス制御回路10A,10Bは相互接続される。
【0038】
電流バランス制御回路10A,10Bに設けた定電流回路6と直列トランジスタTr1,Tr2のコレクタとエミッタが接続される。トランジスタTr1,Tr2のベースは、電流検出回路のコンデンサC0に発生する電流検出電圧Vi1,Vi2を分圧する抵抗R4,R5の分圧点に接続され、分圧電圧によるバイアスを受ける。
【0039】
このトランジスタTr1,Tr2及び抵抗R4,R5の分圧バイアス回路によって、電流検出回路の発生電圧が失われる電源装置の故障を検出した時に、定電流回路6を切り離して他の電源装置からの不平衡電流iの流れ込みを阻止する故障切離し回路が構成される。
【0040】
次に、図1の動作を説明する。電源装置1A,1Bから負荷2に流れる電流が等しいバランス状態では、電流バランス制御回路10A,10Bで負荷2に流れる電流I1,I2に比例した互いに等しい電流検出電圧Vi1、Vi2がコンデンサC0の両端に発生する。この電流検出電圧Vi1、Vi2は抵抗R4,R5で分圧され、トランジスタTr1,Tr2に印可されてオンし、定電流回路6を電流バランス制御回路10A,10Bに接続している。
【0041】
このため電流バランス制御回路10Aでは、電流検出電圧Vi1を電圧源としてコンデンサC0のプラス側から抵抗R0、定電流回路6、トランジスタTr1、ダイオードD1を経てコンデンサC0のマイナス側に定電流Ic1が流れる。
【0042】
また電流バランス制御回路10Bでは、電流検出電圧Vi2を電圧源としてコンデンサC0のプラス側から抵抗R0、定電流回路6、トランジスタTr2、ダイオードD2を経てコンデンサC0のマイナス側に定電流Ic2流れる。このため電流バランス制御回路10A,10Bの間に不平衡電流iは流れない。ここで定電流Ic1、Ic2は同じ電流値であり、例えば1mAとなる。
【0043】
これにより電流バランス制御回路10A,10Bの抵抗R0に発生するバイアス電圧+Viは等しく、増幅器4の入力電圧も等しく、増幅器4は出力制御回路3を出力電圧V0が等しくなるように制御し、負荷2に対する出力電流I1,I2はバランスしている。
【0044】
この出力電圧V0を一定値にする安定制御状態において、電源装置1Aの出力電流I1が電源装置1Bの出力電流I2より大きくなる電流バランスの崩れを生じたとする。このI1>I2となる電流バランスの崩れに対し、電源装置1Aの出力電流I1に応じて電流バランス制御回路10Aの電流検出電圧Vi1が増加し、また電源装置1Bの出力電流I2に応じて電流バランス制御回路10Bの電流検出電圧Vi2は低下し、Vi1>Vi2となる。
【0045】
このため電流バランス制御回路10A,10B間には、電源装置1Aから1Bに向けて不平衡電流iが電流検出電圧の差に応じて流れる。例えば不平衡電流iとして0.2mA流れたとすると、電流バランス制御回路10Aでは抵抗R0に定電流回路6の定電流Ic1=1mAに不平衡電流i=0.2mAを加えた1.2mAの電流が流れ、バイアス電圧+Viが増加する。
【0046】
一方、電流バランス制御回路10Bでは、不平衡電流i=0.2mAが流れ込むことで、抵抗R0には定電流回路6の定電流Ic1=1mAから不平衡電流i=0.2mAを差し引いた0.8mAの電流が流れ、バイアス電圧+Viが減少する。
【0047】
電流バランス制御回路10Aにおいてバイアス+Viが増加すると、増幅器4の出力は低下し、出力制御回路3の出力電圧を下げて電源装置1Aからの出力電流I1を減少させる。一方、電流バランス制御回路10Bにおいてバイアス+Viが減少すると、増幅器4の出力は増加下し、出力制御回路3の出力電圧を上げて電源装置1Bからの出力電流I1を増加させ、最終的に出力電流I1=I2、すなわち不平衡電流i=0となる電流バランスの保持状態を保つようになる。
【0048】
次に片方の電源装置1Bが故障して、電流バランス制御回路10Bの電流検出電圧Vi2が0Vになった場合には、抵抗R4,R5の分圧電圧も0Vとなり、トランジスタTr2がオフし、定電流回路6を電流バランス制御回路10Bから切離す。
【0049】
このため正常な電源装置1Aの電流バランス制御回路10Aにおける電流検出電圧Vi1からバイアス電圧+Viを差し引いた電圧(Vi1−Vi)が、故障した電源装置1Bの電流バランス制御回路10Bに加わっても、不平衡電流iは流れない。
【0050】
従って、正常な電源装置1Aの抵抗R0に流れる電流は、電源装置1Bの故障前の定電流回路6で決まる同じ定電流Ic1であり、バイアス電圧+Viも同じで増幅器4の入力端子に対する入力電圧も変わらないため、増幅器4の出力も変わらない。それ故、電源装置1Bが故障しても電源装置1Aの出力制御回路3の出力電圧V0は変化せず、出力電圧V0の低下を防止することができる。
【0051】
図2は本発明の他の実施形態であり、電源装置1A側を取出して示している。この実施形態は、カレントトランス5の2次巻線に発生する電圧の向きを図1の実施形態に対し逆極性とした場合である。
【0052】
これに対応して電流バランス制御回路10AのD0,D1、コンデンサC0、抵抗R0,R3,R4,R5、定電流回路6およびトランジスタTr1を発生電圧の逆極性に合わせて接続を変更した構成としている。この場合の動作は図1の実施形態と基本的に同じになる。また図1の電源装置1B側も図2の電源装置1Aと同じ構成になる。
【0053】
尚、上記の実施形態にあっては、電流バランス制御回路10A,10Bの故障切離し回路としてトランジスタTr1,Tr2を使用しているが、これに代えて電界効果トランジスタを使用しても良い。
【0054】
即ち、図1のトランジスタTr1,Tr2に代え、MOSFETのドレインとソースを定電流回路6に直列接続し、電流検出回路のコンデンサC0の発生電圧Vi1,Vi2を抵抗R4,R5で分圧してMOSFETのゲートにバイアス電圧として印可すれば良い。
【0055】
【発明の効果】
以上説明したように本発明によれば、冗長運転のために負荷に並列接続された複数の電源装置のいずれかが故障しても、正常な電源装置の出力電圧は低下せず、装置故障に対し負荷に一定電圧を継続して供給する安定した冗長運転を継続することができる。
【0056】
また複数の電源装置のいずれかの故障に対し正常な電源装置の出力電圧は低下しないように電流バランス制御回路に設ける故障切離し回路は、小電力の抵抗2本と小信号トランジスタ1個といった僅かな追加部品で済み、低コストで対応が可能である。
【図面の簡単な説明】
【図1】本発明の実施形態を示した回路図
【図2】本発明の他の実施形態を示した回路図
【図3】従来例の回路図
【符号の説明】
1A,1B:電源装置
2:負荷
3:出力制御回路
4:増幅器
5:カレントトランス
6:定電流回路
10A,10B:電流バランス制御回路
D0〜D4:ダイオード
R0〜R5:抵抗
ZD:ツェナーダイオード
Tr1,Tr2:トランジスタ
I1,I2:出力電流
V0:出力電圧
Vi1,Vi2:電流検出電圧
Ic1,Ic2:定電流
i:不平衡電流
[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a current balance control circuit of a power supply device in which the output sides of a plurality of power supply devices are connected in parallel to a load to balance a parallel current.
[0002]
[Prior art]
BACKGROUND ART Conventionally, as a current balance control circuit used when a plurality of power supply devices are connected in parallel to a load to perform a redundant operation, for example, there is a current balance control circuit as shown in FIG.
[0003]
In FIG. 3, reference numerals 1A and 1B denote power supply devices, and a load 2 is connected in parallel via diodes D3 and D4. Currents I1 and I2 of the same value are supplied from power supply devices 1A and 1B to load 2.
The power supply devices 1A and 1B are provided with an output control circuit 3, and an output voltage V0 stabilized to a constant voltage by switching control is supplied to the load 2. The output voltage V0 is divided by the resistors R1 and R2 and applied to the (-) input terminal of the amplifier 4, and the (+) input terminal is fixedly set to a predetermined reference voltage by the Zener voltage of the Zener diode ZD. .
[0004]
The amplifier 4 amplifies according to a difference voltage between a voltage obtained by adding the voltage + Vi generated by the bias voltage generating resistor R0 to the voltage obtained by dividing the output voltage V0 by the resistors R1 and R2, and a reference voltage of the Zener diode ZD. The output voltage is output to the output control circuit 3 and the output voltage V0 of the output control circuit 3 is controlled to be constant.
[0005]
On the other hand, the power supply devices 1A and 1B are provided with current balance control circuits 10A and 10B. The current balance control circuits 10A and 10B are provided with a current transformer 5 for detecting output currents I1 and I2 supplied to the load 2, and the output of the current transformer 5 is rectified by a diode D0, and the detection voltages Vi1 and Vi2 are supplied to a capacitor C0. Will be charged. Further, a resistor R3 for current-voltage conversion is connected in parallel to the capacitor C0.
[0006]
A constant current circuit 6 is connected via a resistor R0 to a current detection circuit including a current transformer 5, a diode D0, a capacitor C0 and a resistor R3 provided in each of the current balance control circuits 10A and 10B. 6 at the output.
[0007]
Next, the operation of FIG. 3 will be described. In a balanced state in which the currents flowing from the power supply devices 1A and 1B to the load 2 are equal, the current detection voltages Vi1 and Vi2 of the current balance control circuits 10A and 10B are equal. Therefore, in the current balance control circuit 10A, the constant current Ic1 flows from the positive side of the capacitor C0 to the negative side of the capacitor C0 via the resistor R0, the constant current circuit 6, and the diode D1, using the current detection voltage Vi1 as a voltage source.
[0008]
In the current balance control circuit 10B, the constant current Ic2 flows from the plus side of the capacitor C0 to the minus side of the capacitor C0 via the resistor R0, the constant current circuit 6, and the diode D2 using the current detection voltage Vi2 as a voltage source. Therefore, the unbalanced current i does not flow between the current balance control circuits 10A and 10B. Here, the constant currents Ic1 and Ic2 have the same current value, for example, 1 mA.
[0009]
As a result, the bias voltage + Vi generated in the resistors R0 of the current balance control circuits 10A and 10B is equal, the input voltage of the amplifier 4 is also equal, the amplifier 4 controls the output control circuit 3 so that the output voltage V0 is equal, and the load 2 Are balanced.
[0010]
It is assumed that, in the stable control state in which the output voltage V0 is set to a constant value, a current imbalance occurs in which the output current I1 of the power supply 1A becomes larger than the output current I2 of the power supply 1B. In response to the current balance collapse where I1> I2, the current detection voltage Vi1 of the current balance control circuit 10A increases in accordance with the output current I1 of the power supply 1A, and the current balance increases in accordance with the output current I2 of the power supply 1B. The current detection voltage Vi2 of the control circuit 10B decreases, and becomes Vi1> Vi2.
[0011]
Thus, an unbalanced current i flows between the current balance control circuits 10A and 10B from the power supply devices 1A to 1B according to the difference between the current detection voltages. For example, assuming that 0.2 mA flows as the unbalanced current i, the current balance control circuit 10A generates a 1.2 mA current obtained by adding the unbalanced current i = 0.2 mA to the constant current Ic1 of the constant current circuit 6 to the resistor R0. Flow, the bias voltage + Vi increases.
[0012]
On the other hand, in the current balance control circuit 10B, since the unbalanced current i = 0.2 mA flows, the unbalanced current i = 0.2 mA obtained by subtracting the unbalanced current i = 0.2 mA from the constant current Ic1 = 1 mA of the constant current circuit 6 into the resistor R0. A current of 8 mA flows, and the bias voltage + Vi decreases.
[0013]
When the bias + Vi increases in the current balance control circuit 10A, the output of the amplifier 4 decreases, the output voltage of the output control circuit 3 decreases, and the output current I1 from the power supply device 1A decreases. On the other hand, when the bias + Vi decreases in the current balance control circuit 10B, the output of the amplifier 4 increases, the output voltage of the output control circuit 3 increases, the output current I1 from the power supply device 1B increases, and finally the output current I1 = I2, that is, the current balance holding state where the unbalanced current i = 0 is maintained.
[0014]
[Patent Document 1]
JP-A-9-288518
[Problems to be solved by the invention]
However, in such a current balance control circuit of a conventional power supply device, if one of the power supply devices fails and the current detection voltage is cut off, the output voltage of the normal power supply device decreases. There is.
[0016]
For example, if one power supply device 1B fails and the current detection voltage Vi2 of the current balance control circuit 10B becomes 0 V, the current flowing through the resistors R0 and R3 is blocked by the diode D2, but the constant current circuit 6 The unbalanced current i that matches the constant current Ic2 flows from the current balance control circuit 10A of the power supply 1A to the current balance control circuit 10B of the failed power supply 1B.
[0017]
Therefore, a current (Ic1 + Ic2) obtained by adding the constant current flowing through both the constant current circuits 6 to the resistor R0 provided in the current balance control circuit 10A of the normal power supply device 1A flows, and the bias voltage + Vi almost doubles.
[0018]
For this reason, the output of the amplifier 4 decreases, and the output control circuit 3 is controlled so as to reduce the output voltage V0, and the output voltage from the normal power supply 1A to the load 2 decreases.
[0019]
Conventionally, this problem has been dealt with by determining the value of the resistor R0 and the constant current of the constant current circuit 6 so that the output voltage drop caused by the failure of one of the power supply devices is suppressed to a range that can be ignored in the specification of the power supply device. are doing.
[0020]
However, a decrease in the output voltage to the load due to a failure of one of the power supply units means that even if the decrease in the output voltage is within the range that does not impair the specifications of the unit, the failure occurs when multiple power supply units are connected in parallel to the load. However, the original intention of the redundant operation to maintain a stable power supply even when the power failure occurs is impaired, and improvement in this point is desired.
[0021]
The present invention relates to a current balance control of a power supply device in which a normal power supply device does not cause a decrease in output voltage even if a failure occurs in a part of a plurality of redundantly operated power supply devices connected in parallel to a load. It is intended to provide a circuit.
[0022]
[Means for Solving the Problems]
To achieve this object, the present invention is configured as follows.
[0023]
According to the present invention, a plurality of power supplies are connected in parallel to a load for redundant operation, and are mutually connected to a current balance circuit of another power supply that controls so that currents flowing from the plurality of power supplies to the load match. It is intended for a current balance control circuit of a power supply device.
[0024]
The current balance control circuit generates a voltage proportional to the current flowing through the load, and a current detection circuit interconnected with a current detection circuit of another power supply device, a diode for preventing a reverse flow of current to the current detection circuit, A constant current circuit is connected to the current detection circuit and allows a constant current to flow, and a bias voltage generation circuit is inserted and connected to a positive signal line connecting the current detection circuit and the constant current circuit.
[0025]
This bias voltage generation circuit
a) When there is no voltage difference between the current detection circuit and the current detection circuit of another power supply, a bias voltage is generated according to a constant current flowing through the constant current circuit,
b) When the detection voltage of the current detection voltage source has a positive voltage difference with respect to the current detection circuit of another power supply, a current obtained by adding an unbalanced current flowing to another power supply to a constant current flowing to the constant current circuit. Generates a bias voltage according to
c) When the detection voltage of the current detection circuit has a negative voltage difference with respect to the current detection circuit of another power supply, the current is obtained by subtracting the unbalanced current flowing from the other power supply from the constant current flowing in the constant current circuit. Generates a bias voltage according to
d) adding each bias voltage to the output voltage to the amplifier and changing the difference voltage so that the current flowing to the load matches the current flowing to the load from another power supply.
[0026]
In addition to the above, in the current balance control circuit of the present invention, when detecting a failure in which the voltage generated by the current detection circuit is lost, the constant current circuit is disconnected to prevent the flow of unbalanced current from another power supply device. A fault isolation circuit is provided.
[0027]
Therefore, for example, when two power supply units are connected in parallel to a load for redundant operation and one of the power supply units fails and the load current is cut off, the current balance control circuit of the failed power supply unit The voltage generated by the current detection circuit provided in the power supply circuit is lost, and this is detected by the fault disconnection circuit, and the constant current circuit is disconnected to prevent the flow of unbalanced current from the current balance circuit of the normal power supply device. A bias voltage generated in a resistor of a normal current balance control circuit is maintained at a voltage in a stable control state in which output currents of a plurality of power supply devices are balanced. Therefore, even if one of the power supply units fails, the output voltage of the remaining normal power supply unit with respect to the load is controlled to a constant voltage without lowering, and stable redundant operation can be continued.
[0028]
Here, the fault isolation circuit divides the voltage generated by the transistor connected in series with the constant current circuit and the current detection circuit, applies a bias voltage to the base of the transistor, and cuts off the voltage generated by the current detection circuit. A bias circuit for turning off the transistor at the time of detection and disconnecting the constant current circuit.
[0029]
The fault isolation circuit divides the voltage generated by the field effect transistor and the current detection circuit connected in series to the constant current circuit, applies a bias voltage to the gate of the field effect transistor, and cuts off the voltage generated by the current detection circuit. And a bias circuit for turning off the field effect transistor and disconnecting the constant current circuit when a failure is detected.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a circuit diagram showing an embodiment of a current balance control circuit of a power supply device according to the present invention with respect to a connection state for a redundant operation.
[0031]
In FIG. 1, power supplies 1A and 1B are connected in parallel to a load 2 via diodes D3 and D4 in order to supply power by redundant operation. Current balance control circuits 10A and 10B for controlling the output voltage V0 by the output control circuit 3 so as to supply I2 are provided.
[0032]
The output control circuit 3 provided in each of the power supply devices 1A and 1B includes a switching regulator and includes, for example, a DC-DC converter, a rectification output circuit, and a control circuit, and is connected to a primary winding of a transformer provided in the DC-DC converter. The output voltage V0 supplied to the load 2 is stably controlled to a constant voltage by ON / OFF control of the switch element.
[0033]
The output voltage V0 is divided by the resistors R1 and R2 and applied to the (-) input terminal of the amplifier 4, and the (+) input terminal is fixedly set to a predetermined reference voltage by the Zener voltage of the Zener diode ZD. .
[0034]
The amplifier 4 inputs a voltage obtained by adding the bias voltage + Vi generated by the resistor R0 of the current balance control circuits 10A and 10B to the voltage obtained by dividing the output voltage V0 by the resistors R1 and R2, and outputs the reference voltage of the Zener diode ZD. Is output to the output control circuit 3 and the output voltage V0 of the output control circuit 3 is controlled to be constant.
[0035]
The current balance control circuits 10A and 10B provided in the power supply devices 1A and 1B are provided with a current transformer 5 for detecting output currents I1 and I2 supplied to the load 2. The current transformer 5 supplies a current through ON / OFF control of a switch element on a primary side of a DC-DC converter provided in the output control circuit 3 to a primary winding, and generates a voltage in an upward arrow direction on a secondary side. .
[0036]
The output of the current transformer 5 is rectified by the diode D0 and charged in the capacitor C0 as current detection voltages Vi1 and Vi2. A resistor R3 for current-voltage conversion is connected in parallel to the capacitor C0, and functions as a voltage source that generates a voltage proportional to the detected current.
[0037]
A constant current circuit 6 is connected via a resistor R0 to a current detection circuit including a current transformer 5, a diode D0, a capacitor C0, and a resistor R3 provided in the current balance control circuits 10A and 10B. On the output side, the current balance control circuits 10A and 10B are interconnected.
[0038]
The constant current circuit 6 provided in the current balance control circuits 10A and 10B is connected to the collectors and emitters of the series transistors Tr1 and Tr2. The bases of the transistors Tr1 and Tr2 are connected to the voltage dividing points of the resistors R4 and R5 for dividing the current detection voltages Vi1 and Vi2 generated in the capacitor C0 of the current detection circuit, and receive a bias by the divided voltage.
[0039]
When a failure of the power supply that causes the voltage generated by the current detection circuit to be lost is detected by the voltage dividing bias circuit of the transistors Tr1 and Tr2 and the resistors R4 and R5, the constant current circuit 6 is disconnected and unbalanced from another power supply. A fault isolation circuit for preventing the current i from flowing in is formed.
[0040]
Next, the operation of FIG. 1 will be described. In a balanced state in which the currents flowing from the power supply devices 1A and 1B to the load 2 are equal, the current detection voltages Vi1 and Vi2 equal to the currents I1 and I2 flowing to the load 2 in the current balance control circuits 10A and 10B are applied to both ends of the capacitor C0. appear. The current detection voltages Vi1 and Vi2 are divided by the resistors R4 and R5, applied to the transistors Tr1 and Tr2 and turned on, and connect the constant current circuit 6 to the current balance control circuits 10A and 10B.
[0041]
Therefore, in the current balance control circuit 10A, the constant current Ic1 flows from the plus side of the capacitor C0 to the minus side of the capacitor C0 via the resistor R0, the constant current circuit 6, the transistor Tr1, and the diode D1 using the current detection voltage Vi1 as a voltage source.
[0042]
In the current balance control circuit 10B, the constant current Ic2 flows from the plus side of the capacitor C0 to the minus side of the capacitor C0 via the resistor R0, the constant current circuit 6, the transistor Tr2, and the diode D2 using the current detection voltage Vi2 as a voltage source. Therefore, the unbalanced current i does not flow between the current balance control circuits 10A and 10B. Here, the constant currents Ic1 and Ic2 have the same current value, for example, 1 mA.
[0043]
As a result, the bias voltage + Vi generated in the resistors R0 of the current balance control circuits 10A and 10B is equal, the input voltage of the amplifier 4 is also equal, the amplifier 4 controls the output control circuit 3 so that the output voltage V0 is equal, and the load 2 Are balanced.
[0044]
It is assumed that, in the stable control state in which the output voltage V0 is set to a constant value, a current imbalance occurs in which the output current I1 of the power supply 1A becomes larger than the output current I2 of the power supply 1B. In response to the current balance collapse where I1> I2, the current detection voltage Vi1 of the current balance control circuit 10A increases in accordance with the output current I1 of the power supply 1A, and the current balance increases in accordance with the output current I2 of the power supply 1B. The current detection voltage Vi2 of the control circuit 10B decreases, and becomes Vi1> Vi2.
[0045]
Thus, an unbalanced current i flows between the current balance control circuits 10A and 10B from the power supply devices 1A to 1B according to the difference between the current detection voltages. For example, assuming that 0.2 mA flows as the unbalanced current i, the current balance control circuit 10A generates a 1.2 mA current obtained by adding the unbalanced current i = 0.2 mA to the constant current Ic1 of the constant current circuit 6 to the resistor R0. Flow, the bias voltage + Vi increases.
[0046]
On the other hand, in the current balance control circuit 10B, since the unbalanced current i = 0.2 mA flows, the unbalanced current i = 0.2 mA obtained by subtracting the unbalanced current i = 0.2 mA from the constant current Ic1 = 1 mA of the constant current circuit 6 into the resistor R0. A current of 8 mA flows, and the bias voltage + Vi decreases.
[0047]
When the bias + Vi increases in the current balance control circuit 10A, the output of the amplifier 4 decreases, the output voltage of the output control circuit 3 decreases, and the output current I1 from the power supply device 1A decreases. On the other hand, when the bias + Vi decreases in the current balance control circuit 10B, the output of the amplifier 4 increases and decreases, the output voltage of the output control circuit 3 increases, and the output current I1 from the power supply device 1B increases. The current balance holding state where I1 = I2, that is, the unbalanced current i = 0 is maintained.
[0048]
Next, when one of the power supply devices 1B fails and the current detection voltage Vi2 of the current balance control circuit 10B becomes 0V, the divided voltages of the resistors R4 and R5 also become 0V, and the transistor Tr2 is turned off. The current circuit 6 is disconnected from the current balance control circuit 10B.
[0049]
Therefore, even if the voltage (Vi1-Vi) obtained by subtracting the bias voltage + Vi from the current detection voltage Vi1 in the current balance control circuit 10A of the normal power supply device 1A is applied to the current balance control circuit 10B of the failed power supply device 1B, No equilibrium current i flows.
[0050]
Therefore, the current flowing through the resistor R0 of the normal power supply 1A is the same constant current Ic1 determined by the constant current circuit 6 before the failure of the power supply 1B, the bias voltage + Vi is the same, and the input voltage to the input terminal of the amplifier 4 is also Since it does not change, the output of the amplifier 4 does not change. Therefore, even if the power supply device 1B fails, the output voltage V0 of the output control circuit 3 of the power supply device 1A does not change, and it is possible to prevent the output voltage V0 from decreasing.
[0051]
FIG. 2 shows another embodiment of the present invention, in which the power supply device 1A side is taken out and shown. This embodiment is a case where the direction of the voltage generated in the secondary winding of the current transformer 5 has a polarity opposite to that of the embodiment of FIG.
[0052]
Correspondingly, the connections of D0 and D1, the capacitor C0, the resistors R0, R3, R4, and R5, the constant current circuit 6, and the transistor Tr1 of the current balance control circuit 10A are changed according to the opposite polarity of the generated voltage. . The operation in this case is basically the same as the embodiment of FIG. The power supply device 1B in FIG. 1 also has the same configuration as the power supply device 1A in FIG.
[0053]
In the above embodiment, the transistors Tr1 and Tr2 are used as fault isolation circuits for the current balance control circuits 10A and 10B, but field effect transistors may be used instead.
[0054]
That is, instead of the transistors Tr1 and Tr2 of FIG. 1, the drain and the source of the MOSFET are connected in series to the constant current circuit 6, and the generated voltages Vi1 and Vi2 of the capacitor C0 of the current detection circuit are divided by the resistors R4 and R5, and What is necessary is just to apply a bias voltage to the gate.
[0055]
【The invention's effect】
As described above, according to the present invention, even if any one of a plurality of power supplies connected in parallel to a load for redundant operation fails, the output voltage of a normal power supply does not decrease, and On the other hand, stable redundant operation of continuously supplying a constant voltage to the load can be continued.
[0056]
Further, a fault isolation circuit provided in the current balance control circuit so that the output voltage of the normal power supply does not decrease in response to a failure of any of the plurality of power supplies, may be a small one such as two low power resistors and one small signal transistor. Only additional parts are required, and it can be handled at low cost.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is a circuit diagram showing another embodiment of the present invention. FIG. 3 is a circuit diagram of a conventional example.
1A, 1B: Power supply device 2: Load 3: Output control circuit 4: Amplifier 5: Current transformer 6: Constant current circuits 10A, 10B: Current balance control circuits D0 to D4: Diodes R0 to R5: Resistance ZD: Zener diode Tr1, Tr2: transistors I1, I2: output current V0: output voltages Vi1, Vi2: current detection voltages Ic1, Ic2: constant current i: unbalanced current

Claims (3)

冗長運転のために複数の電源装置を負荷に並列接続し、前記複数の電源装置から負荷に流れる電流が一致するように制御する他の電源装置の電流バランス制御回路と相互に接続された電源装置の電流バランス回路に於いて、
前記負荷に流れる電流に比例した電圧を発生し、他の電源装置の電流検出回路と相互接続される電流検出回路と、
前記電流検出回路に対する電流の逆流を阻止するダイオードと、
前記電流検出回路に接続され一定電流を流す定電流回路と、
前記電流検出回路と定電流回路を結ぶプラス側信号ラインに挿入接続され、前記電流検出回路と他の電源装置の電流検出回路との間に電圧差がない時は前記定電流回路に流す一定電流に応じたバイアス電圧を発生し、前記電流検出電圧源の検出電圧が他の電源装置の電流検出回路に対しプラスの電圧差を持つ時は前記定電流回路に流す一定電流に他の電源装置に流れ出す不平衡電流を加えた電流に応じたバイアス電圧を発生し、更に、前記電流検出回路の検出電圧が他の電源装置の電流検出回路に対しマイナスの電圧差を持つ時は前記定電流回路に流す一定電流から他の電源装置から流れ込む不平衡電流を差し引いた電流に応じたバイアス電圧を発生し、前記各バイアス電圧を前記増幅器に対する出力電圧に加算して負荷に流れる電流が他の電源装置から負荷に流れる電流に一致するように差電圧を変化させるバイアス電圧発生回路と、
前記電流検出回路の発生電圧が失われる故障を検出した時に、前記定電流回路を切り離して他の電源装置からの不平衡電流の流れ込みを阻止する故障切離し回路と、
を備えたことを特徴とする電源装置の電流バランス制御回路。
A power supply unit connected to a load in parallel with a plurality of power supply units for redundant operation and connected to a current balance control circuit of another power supply unit for controlling currents flowing from the plurality of power supply units to the load to be equal to each other In the current balance circuit of
A current detection circuit that generates a voltage proportional to the current flowing through the load and is interconnected with a current detection circuit of another power supply device;
A diode for preventing backflow of current to the current detection circuit;
A constant current circuit connected to the current detection circuit and flowing a constant current;
A constant current flowing through the constant current circuit when there is no voltage difference between the current detection circuit and the current detection circuit of another power supply device, which is inserted and connected to a positive signal line connecting the current detection circuit and the constant current circuit; When the detected voltage of the current detection voltage source has a positive voltage difference with respect to the current detection circuit of another power supply, a constant current flowing through the constant current circuit is applied to the other power supply. A bias voltage is generated in accordance with the current obtained by adding the unbalanced current flowing out.If the detected voltage of the current detection circuit has a negative voltage difference with respect to the current detection circuit of another power supply, the constant current circuit is generated. A bias voltage corresponding to a current obtained by subtracting an unbalanced current flowing from another power supply device from a constant current flowing is generated, and each of the bias voltages is added to an output voltage to the amplifier, so that a current flowing to a load becomes another. A bias voltage generating circuit for changing the differential voltage to match the current flowing from a source device to a load,
A failure isolation circuit that disconnects the constant current circuit to prevent the flow of unbalanced current from another power supply device when detecting a failure in which the generated voltage of the current detection circuit is lost;
A current balance control circuit for a power supply device, comprising:
請求項1記載の電源装置の電流バランス制御回路に於いて、前記故障切離し回路は、
前記定電流回路に直列接続されたトランジスタと、
前記電流検出回路の発生電圧を分圧して前記トランジスタのベースにバイアス電圧を印加し、前記電流検出回路の発生電圧が断たれる故障検出時に前記トランジスタをオフして前記定電流回路を切離すバイアス回路と、
を備えたことを特徴とする電源装置の電流バランス制御回路。
The current balance control circuit of the power supply device according to claim 1, wherein the fault isolation circuit includes:
A transistor connected in series to the constant current circuit;
A bias that divides a voltage generated by the current detection circuit and applies a bias voltage to the base of the transistor, and turns off the transistor to disconnect the constant current circuit when a failure is detected in which the voltage generated by the current detection circuit is cut off. Circuit and
A current balance control circuit for a power supply device, comprising:
請求項1記載の電源装置の電流バランス制御回路に於いて、前記故障切離し回路は、
前記定電流回路に直列接続された電界効果トランジスタと、
前記電流検出回路の発生電圧を分圧して前記電界効果トランジスタのゲートにバイアス電圧を印加し、前記電流検出回路の発生電圧が断たれる故障検出時に前記電界効果トランジスタをオフして前記定電流回路を切離すバイアス回路と、
を備えたことを特徴とする電源装置の電流バランス制御回路。
The current balance control circuit of the power supply device according to claim 1, wherein the fault isolation circuit includes:
A field effect transistor connected in series to the constant current circuit,
Applying a bias voltage to the gate of the field effect transistor by dividing the voltage generated by the current detection circuit, and turning off the field effect transistor upon detection of a failure in which the voltage generated by the current detection circuit is cut off; And a bias circuit for disconnecting
A current balance control circuit for a power supply device, comprising:
JP2002331584A 2002-11-15 2002-11-15 Current balance control circuit for power supply Expired - Fee Related JP3897251B2 (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007143292A (en) * 2005-11-18 2007-06-07 Cosel Co Ltd Parallel operation power supply system
CN101958542A (en) * 2010-07-09 2011-01-26 深圳键桥通讯技术股份有限公司 Method for intelligently balancing load among modules in communication power-supply system
JP2017135089A (en) * 2016-01-29 2017-08-03 コイト電工株式会社 Power supply system and railroad vehicle
CN112445309A (en) * 2019-08-30 2021-03-05 比亚迪股份有限公司 Redundant power supply for computer control system and computer control system
EP3996225A1 (en) 2020-11-05 2022-05-11 Yazaki Corporation Power supply switching control system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007143292A (en) * 2005-11-18 2007-06-07 Cosel Co Ltd Parallel operation power supply system
CN101958542A (en) * 2010-07-09 2011-01-26 深圳键桥通讯技术股份有限公司 Method for intelligently balancing load among modules in communication power-supply system
JP2017135089A (en) * 2016-01-29 2017-08-03 コイト電工株式会社 Power supply system and railroad vehicle
WO2017131227A1 (en) * 2016-01-29 2017-08-03 コイト電工株式会社 Power supply system and railroad car
US10668811B2 (en) 2016-01-29 2020-06-02 Koito Electric Industries, Ltd. Power supply system and railroad car
CN112445309A (en) * 2019-08-30 2021-03-05 比亚迪股份有限公司 Redundant power supply for computer control system and computer control system
EP3996225A1 (en) 2020-11-05 2022-05-11 Yazaki Corporation Power supply switching control system
US11594911B2 (en) 2020-11-05 2023-02-28 Yazaki Corporation Power supply switching control system

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