JP2005253261A - Power supply system and electronic equipment - Google Patents

Power supply system and electronic equipment Download PDF

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JP2005253261A
JP2005253261A JP2004063860A JP2004063860A JP2005253261A JP 2005253261 A JP2005253261 A JP 2005253261A JP 2004063860 A JP2004063860 A JP 2004063860A JP 2004063860 A JP2004063860 A JP 2004063860A JP 2005253261 A JP2005253261 A JP 2005253261A
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power supply
supply system
voltage
fuel cell
constant voltage
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JP2005253261A5 (en
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Shunichi Abe
俊一 阿部
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Ricoh Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously achieve a high withstand voltage and a small voltage drop by devising a circuit configuration to realize low loss/high efficiency of a power supply system. <P>SOLUTION: A silicon diode 5 having a high withstand voltage as electric performance and a Schottky diode 6 having a small voltage drop and a small power loss are combined to reduce power loss with the silicon diode 5 which suffers from a big power loss, when the voltage applied to the diodes 5, 6 is in a forward direction. While a relay contact point 8 is controlled opening and closing with a control element 9 corresponding to the magnitude of a fuel battery 1 and a constant voltage power supply 3 so as not to apply a reverse direction voltage to the Schottky diode 6, when the voltage applied to the diodes 5, 6 is in a reverse direction. Thereby, the high withstand voltage and the small voltage drop regarding a rectifying element are simultaneously achieved to realize the low loss/high efficiency of the power supply system. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、燃料電池等を用いた電源システム及び当該電源システムを備える複写機等の電子機器に関する。   The present invention relates to a power supply system using a fuel cell or the like and an electronic apparatus such as a copying machine including the power supply system.

特許文献1には、燃料電池を用いた燃料発電装置が開示されている。また、燃料電池に限らず、二次電池と充電装置とによる発電装置を用いた画像形成装置等に関する提案例もある(例えば、特許文献2参照)。   Patent Document 1 discloses a fuel power generation apparatus using a fuel cell. In addition to the fuel cell, there is a proposal example related to an image forming apparatus using a power generation device including a secondary battery and a charging device (see, for example, Patent Document 2).

特開平8−50902号公報JP-A-8-50902 特許第3310767号公報Japanese Patent No. 3310767

燃料電池の出力電圧は不安定なため、定電圧電源で電圧を安定化してから負荷に供給するのが一般的である。定電圧電源の入力端子には入力電圧の変動を吸収するための大容量のコンデンサが並列に接続されている。   Since the output voltage of the fuel cell is unstable, the voltage is generally stabilized by a constant voltage power supply and then supplied to the load. A large-capacity capacitor for absorbing fluctuations in the input voltage is connected in parallel to the input terminal of the constant voltage power supply.

ここに、燃料電池セルは水素と酸素を化学反応させて水ができる際のエネルギを電力と言う形で取り出す電源であり、逆に燃料電池セルに対して電流を流し込むと水の電気分解で水素と酸素を発生するだけでなく燃料電池の特性劣化が起きるため、定電圧電源の入力側のコンデンサからの逆電流を整流素子、例えばダイオードで防止する必要がある。即ち、燃料電池が何らかのトラブルで、燃料供給が追いつかなくなると発電電圧よりも定電圧電源のコンデンサの電圧の方が高くなり、逆に燃料電池セルに電流が流れ込んでしまうので、このような逆電流を防止するためにダイオードが挿入される。   Here, the fuel cell is a power source that takes out the energy when water is produced by chemically reacting hydrogen and oxygen in the form of electric power, and conversely, when current is supplied to the fuel cell, hydrogen is electrolyzed to produce hydrogen. In addition to the generation of oxygen, the characteristics of the fuel cell are deteriorated. Therefore, it is necessary to prevent the reverse current from the capacitor on the input side of the constant voltage power source by a rectifying element, for example, a diode. That is, if the fuel cell cannot catch up with the fuel cell due to some trouble, the voltage of the capacitor of the constant voltage power supply becomes higher than the generated voltage, and the current flows into the fuel cell. A diode is inserted to prevent this.

しかし、高耐圧と低電圧降下とを両立できるダイオードがなく、耐圧が1000V以上と高いシリコンダイオードは順方向の電圧降下が1V程度であり、ショットキーダイオードに比べ、電力損失が2倍位になってしまう。また、順方向電圧降下が0.5V程度と小さいショットキーダイオードは電力損失が少ない反面、耐圧がせいぜい100V程度迄であり、あまり電圧の高い個所には使用できない。   However, there is no diode that can achieve both high withstand voltage and low voltage drop, and silicon diodes with high withstand voltage of 1000V or higher have a forward voltage drop of about 1V, and the power loss is about twice that of Schottky diodes. End up. A Schottky diode with a forward voltage drop as small as about 0.5 V has little power loss, but has a withstand voltage of up to about 100 V, and cannot be used in a place with a very high voltage.

そのため、電圧が高い電源システムでは低電圧降下なダイオードが使えないことから、例えば高耐圧なシリコンダイオードを用いた場合、10Aの電流を流すと10A×1V=10Wと損失が多かった。   For this reason, a diode with a low voltage drop cannot be used in a power supply system with a high voltage. For example, when a silicon diode having a high withstand voltage is used, a loss of 10 A × 1 V = 10 W was large when a current of 10 A was passed.

本発明の目的は、回路構成の工夫により高耐圧と低電圧降下とを両立し、電源システムの低損失・高効率化を図ることである。   An object of the present invention is to achieve both a high withstand voltage and a low voltage drop by devising a circuit configuration, and to achieve low loss and high efficiency of a power supply system.

請求項1記載の発明の電源システムは、電池或いは発電装置の出力側に定電圧電源を接続した電源システムにおいて、前記電池或いは発電装置と前記定電圧電源との間で同一の整流方向に接続されて電気的能力の異なる複数の整流素子を備える。   The power supply system according to claim 1 is a power supply system in which a constant voltage power source is connected to an output side of a battery or a power generator, and is connected in the same rectification direction between the battery or the power generator and the constant voltage power source. A plurality of rectifying elements having different electrical capabilities.

請求項2記載の発明の電源システムは、燃料電池の出力側に定電圧電源を接続した電源システムにおいて、前記燃料電池と前記定電圧電源の間で同一の整流方向に接続されて電気的能力の異なる複数の整流素子を備える。   According to a second aspect of the present invention, there is provided a power supply system in which a constant voltage power source is connected to the output side of the fuel cell, the electric power system connected in the same rectification direction between the fuel cell and the constant voltage power source. A plurality of different rectifying elements are provided.

請求項3記載の発明は、請求項1又は2記載の電源システムにおいて、複数の前記整流素子の一つは、他の整流素子よりも電圧降下の低い電気的能力を有する整流素子である。   According to a third aspect of the present invention, in the power supply system according to the first or second aspect, one of the plurality of rectifying elements is a rectifying element having an electrical capability with a lower voltage drop than the other rectifying elements.

請求項4記載の発明は、請求項3記載の電源システムにおいて、他の整流素子よりも電圧降下の低い電気的能力を有する前記整流素子は、ショットキーダイオードである。   According to a fourth aspect of the present invention, in the power supply system according to the third aspect, the rectifying element having an electrical capability with a lower voltage drop than other rectifying elements is a Schottky diode.

請求項5記載の発明の電源システムは、燃料電池の出力側に定電圧電源を接続した電源システムにおいて、前記燃料電池と前記定電圧電源との間に接続された第1の整流素子とスイッチとの並列回路と、この並列回路に直列接続されて前記第1の整流素子よりも電圧降下の低い電気的能力を有する第2の整流素子と、を備える。   According to a fifth aspect of the present invention, there is provided a power supply system in which a constant voltage power source is connected to the output side of the fuel cell, the first rectifier element and the switch connected between the fuel cell and the constant voltage power source. And a second rectifier element connected in series to the parallel circuit and having an electrical capability with a voltage drop lower than that of the first rectifier element.

請求項6記載の発明の電源システムは、燃料電池の出力側に定電圧電源を接続した電源システムにおいて、前記燃料電池と前記定電圧電源との間に接続された第1の整流素子とスイッチとの並列回路と、この並列回路中で前記スイッチに直列接続されて前記第1の整流素子よりも電圧降下の低い電気的能力を有する第2の整流素子と、を備える。   According to a sixth aspect of the present invention, there is provided a power supply system in which a constant voltage power source is connected to the output side of the fuel cell, the first rectifier element and the switch connected between the fuel cell and the constant voltage power source. And a second rectifying element connected in series to the switch in the parallel circuit and having an electrical capability with a voltage drop lower than that of the first rectifying element.

請求項7記載の発明は、請求項5又は6記載の電源システムにおいて、前記燃料電池の出力電圧より前記定電圧電源の入力端子電圧が或る値より小さくなった時に前記スイッチをONさせる制御素子を備える。   According to a seventh aspect of the present invention, in the power supply system according to the fifth or sixth aspect, the control element that turns on the switch when the input terminal voltage of the constant voltage power supply becomes smaller than a certain value from the output voltage of the fuel cell. Is provided.

請求項8記載の発明は、請求項5ないし7の何れか一記載の電源システムにおいて、前記燃料電池の出力電圧より前記定電圧電源の入力端子電圧が或る値より大きくなった時に前記スイッチをOFFさせる制御素子を備える。   According to an eighth aspect of the present invention, in the power supply system according to any one of the fifth to seventh aspects, the switch is turned on when the input terminal voltage of the constant voltage power source becomes larger than a certain value than the output voltage of the fuel cell. A control element to be turned off is provided.

請求項9記載の発明は、請求項5ないし8の何れか一記載の電源システムにおいて、前記スイッチは、FETである。   According to a ninth aspect of the present invention, in the power supply system according to any one of the fifth to eighth aspects, the switch is an FET.

請求項10記載の発明は、請求項5ないし9の何れか一記載の電源システムにおいて、前記第2の整流素子に並列接続された抵抗を備える。   According to a tenth aspect of the present invention, in the power supply system according to any one of the fifth to ninth aspects, a resistor connected in parallel to the second rectifying element is provided.

請求項11記載の発明の電子機器は、請求項1ないし10の何れか一記載の電源システムを備え、当該電源システムから供給される電力で各負荷が動作する。   An electronic apparatus according to an eleventh aspect includes the power supply system according to any one of the first to tenth aspects, and each load operates with electric power supplied from the power supply system.

請求項12記載の発明は、請求項11記載の電子機器において、前記電源システムを内蔵する。   According to a twelfth aspect of the present invention, in the electronic device according to the eleventh aspect, the power supply system is incorporated.

本発明によれば、例えば電気的能力として耐圧の高いシリコンダイオードと、電圧降下が低くて電力損失の少ないショットキーダイオードとの組合せのように電気的能力の異なる複数の整流素子を備え、これらの整流素子にかかる電圧が順方向の場合には電力損失の大きいシリコンダイオードでの電力損失をなくす一方、これらの整流素子にかかる電圧が逆方向の場合にはショットキーダイオードには逆方向の電圧が印加されないようにすることで、高耐圧と低電圧降下とを両立し、電源システムの低損失・高効率化を図ることができる。   According to the present invention, for example, a plurality of rectifying elements having different electrical capacities such as a combination of a silicon diode having a high withstand voltage as an electrical capability and a Schottky diode with a low voltage drop and low power loss are provided. When the voltage applied to the rectifying element is in the forward direction, the power loss in the silicon diode having a large power loss is eliminated. On the other hand, when the voltage applied to these rectifying elements is in the reverse direction, the reverse voltage is applied to the Schottky diode. By preventing the voltage from being applied, it is possible to achieve both high withstand voltage and low voltage drop, and to achieve low loss and high efficiency of the power supply system.

本発明を実施するための最良の形態について図面を参照して説明する。   The best mode for carrying out the present invention will be described with reference to the drawings.

[第一の実施の形態]
本発明の第一の実施の形態を図1に基づいて説明する。本実施の形態は、電池或いは発電装置として、燃料電池1を用いた電源システムPSへの適用例を示す。燃料電池1の出力側には、燃料電池1の出力電圧を安定化させて対象となる負荷2に供給する定電圧電源3が接続されている。この定電圧電源3の入力端子間には入力電圧の変動を吸収するための大容量のコンデンサ4が接続されている。
[First embodiment]
A first embodiment of the present invention will be described with reference to FIG. The present embodiment shows an application example to a power supply system PS using a fuel cell 1 as a battery or a power generation device. Connected to the output side of the fuel cell 1 is a constant voltage power supply 3 that stabilizes the output voltage of the fuel cell 1 and supplies it to the target load 2. A large-capacitance capacitor 4 is connected between the input terminals of the constant voltage power supply 3 to absorb fluctuations in the input voltage.

このような燃料電池1の出力側と定電圧電源3の入力側との間には、複数、例えば2個の整流素子5,6が整流方向を燃料電池1側から定電圧電源3側に揃えて接続されている。ここに、整流素子としては、例えば、シリコンダイオード、SCR、ショットキーダイオード、ファーストリカバリーダイオード、ゲルマニュームダイオード、鉱石検波器、セレン整流器、真空管、水銀整流管等の整流作用を有するものを用い得るわけであるが、整流素子5,6同士はその電気的能力が異なるものが用いられる。本実施の形態では、例えば整流素子(第1の整流素子)5としては高耐圧なシリコンダイオード(以下、シリコンダイオード5とする)が用いられ、整流素子(第2の整流素子)6としては整流素子5に比べて電圧降下の低い電気的能力を有するショットキーダイオード(以下、ショットキーダイオード6とする)が用いられている。ここに、シリコンダイオード5にはリレーコイル7により開閉されるスイッチとしてのリレー接点8が並列に接続されて並列回路が構成され、ショットキーダイオード6はこの並列回路に対して直列に接続されている。また、燃料電池1の出力電圧と定電圧電源3の入力端子電圧との大小関係を比較してその大小関係に応じてリレーコイル7への通電を制御しリレー接点8を開閉制御(ON・OFF制御)する制御素子としての差動増幅器10が設けられている。この差動増幅器10は、燃料電池1の出力電圧より定電圧電源3の入力端子電圧が或る値より小さくなった時にはリレーコイル7に通電してリレー接点8を閉じ(ON)させ、燃料電池1の出力電圧より定電圧電源の入力端子電圧が或る値より大きくなった時にはリレーコイル7への通電を止めリレー接点8を開放(OFF)させるように機能する。なお、10はこの差動増幅器9を動作させる駆動電源用バッテリである。   Between the output side of the fuel cell 1 and the input side of the constant voltage power source 3, a plurality of, for example, two rectifying elements 5 and 6 align the rectification direction from the fuel cell 1 side to the constant voltage power source 3 side. Connected. Here, as the rectifying element, for example, a silicon diode, an SCR, a Schottky diode, a fast recovery diode, a germanium diode, an ore detector, a selenium rectifier, a vacuum tube, a mercury rectifying tube, or the like can be used. However, the rectifying elements 5 and 6 are different in electric capacity. In the present embodiment, for example, a high-breakdown-voltage silicon diode (hereinafter referred to as silicon diode 5) is used as the rectifying element (first rectifying element) 5, and the rectifying element (second rectifying element) 6 is rectified. A Schottky diode (hereinafter referred to as a Schottky diode 6) having an electrical capability with a voltage drop lower than that of the element 5 is used. Here, a relay contact 8 as a switch opened and closed by a relay coil 7 is connected in parallel to the silicon diode 5 to constitute a parallel circuit, and the Schottky diode 6 is connected in series to the parallel circuit. . Further, the magnitude relationship between the output voltage of the fuel cell 1 and the input terminal voltage of the constant voltage power source 3 is compared, and the energization to the relay coil 7 is controlled according to the magnitude relationship, and the relay contact 8 is controlled to be opened and closed (ON / OFF). A differential amplifier 10 is provided as a control element to be controlled. The differential amplifier 10 energizes the relay coil 7 to close (ON) the relay contact 8 when the input terminal voltage of the constant voltage power supply 3 is smaller than a certain value than the output voltage of the fuel cell 1, thereby closing (ON) the relay contact 8. When the input terminal voltage of the constant voltage power supply exceeds a certain value from the output voltage of 1, the relay coil 7 is deenergized and the relay contact 8 is opened (OFF). Reference numeral 10 denotes a drive power supply battery for operating the differential amplifier 9.

このような構成において、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より高い時(ダイオード5,6にかかる電圧が順方向の場合)は、差動増幅器9の出力がL(Low)になりリレーコイル7に電流が流れるため、リレー接点8が閉じ(ONし)、シリコンダイオード5のアノード、カソード間をショートする。従って、燃料電池1から電力を取り出している時はシリコンダイオード5での電圧降下はなく、ショットキーダイオード6だけの電圧降下となるので、電力損失を少なくすることができる。   In such a configuration, when the output voltage of the fuel cell 1 is higher than the input terminal voltage of the constant voltage power supply 3 (when the voltage applied to the diodes 5 and 6 is forward), the output of the differential amplifier 9 is L (Low). Since the current flows through the relay coil 7, the relay contact 8 is closed (turned ON), and the anode and cathode of the silicon diode 5 are short-circuited. Therefore, when power is extracted from the fuel cell 1, there is no voltage drop at the silicon diode 5, but only at the Schottky diode 6, so that power loss can be reduced.

反対に、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より低い時(ダイオード5,6にかかる電圧が逆方向の場合)は、差動増幅器9の出力がH(High)になりリレーコイル7に電流が流れないため、リレー接点8が開き、シリコンダイオード5のアノード、カソード間には電気的に何もないのと同じになる。従って、定電圧電源3の入力端子から燃料電池1の出力端子に逆に電流が流れようとしても耐電圧の高いシリコンダイオード5で堰き止められるので耐電圧の低いショットキーダイオード6に大きな逆電圧が印加されることはない。   Conversely, when the output voltage of the fuel cell 1 is lower than the input terminal voltage of the constant voltage power supply 3 (when the voltage applied to the diodes 5 and 6 is in the reverse direction), the output of the differential amplifier 9 becomes H (High). Since no current flows through the relay coil 7, the relay contact 8 is opened, which is the same as when there is nothing electrically between the anode and the cathode of the silicon diode 5. Therefore, even if a current flows backward from the input terminal of the constant voltage power supply 3 to the output terminal of the fuel cell 1, it is blocked by the silicon diode 5 having a high withstand voltage, so that a large reverse voltage is applied to the Schottky diode 6 having a low withstand voltage. It is never applied.

より詳細な動作制御として、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より高い状態から、例えば急激に燃料や空気の供給が少ない状態になると、燃料電池1の出力電圧が低下し、定電圧電源3の入力端子電圧より燃料電池1の出力電圧が低くなってしまう。この時、上述したように、閉じていたリレー接点8が開き、シリコンダイオード5のアノード、カソード間には電気的に何もないのと同じになるが、リレー接点8の動作よりも電圧の低下のほうが早い場合には耐電圧の高いシリコンダイオード5が機能しないが、電圧差があまり大きくない間は耐電圧の低いショットキーダイオード6で堰き止めることができる。ショットキーダイオード6で堰き止めている間に、リレー接点8が開ききれば今度は耐電圧の高いシリコンダイオード5が機能するようになるので大きな逆電圧が耐電圧の低いショットキーダイオード6に印加されることはなく、定電圧電源3から燃料電池1に電流が流れ込むこともない。   As more detailed operation control, when the output voltage of the fuel cell 1 is higher than the input terminal voltage of the constant voltage power supply 3, for example, when the supply of fuel or air suddenly decreases, the output voltage of the fuel cell 1 decreases. The output voltage of the fuel cell 1 becomes lower than the input terminal voltage of the constant voltage power supply 3. At this time, as described above, the relay contact 8 that has been closed opens and is the same as when there is nothing electrically between the anode and the cathode of the silicon diode 5, but the voltage drops more than the operation of the relay contact 8. If this is earlier, the silicon diode 5 having a high withstand voltage does not function, but can be blocked by the Schottky diode 6 having a low withstand voltage while the voltage difference is not so large. If the relay contact 8 is fully opened while the Schottky diode 6 is dammed, the silicon diode 5 having a high withstand voltage will function, so that a large reverse voltage is applied to the Schottky diode 6 having a low withstand voltage. No current flows from the constant voltage power supply 3 to the fuel cell 1.

ちなみに、リレー接点8が全ての整流素子5,6をバイパスする形でショートする回路構成の場合は、接点が開ききるまでの間は逆方向の電流を阻止するものがないので、この過度期は定電圧電源3から燃料電池1に電流が流れ込んでしまい、高価な燃料電池1にダメージを与えてしまう。これは、リレー接点8の動作例で説明したが、これが後述の無接点の半導体素子に変わって切り替え動作時間が早くなっても、短い時間の間はやはり電圧電源から燃料電池に電流が流れ込んでしまう。   Incidentally, in the case of a circuit configuration in which the relay contact 8 is short-circuited so as to bypass all the rectifying elements 5 and 6, there is nothing to prevent reverse current until the contacts are fully opened, so this transient period is Current flows from the constant voltage power source 3 to the fuel cell 1, which damages the expensive fuel cell 1. This has been described in the operation example of the relay contact 8, but even if this is changed to a non-contact semiconductor element to be described later and the switching operation time is shortened, the current flows from the voltage power source to the fuel cell for a short time. End up.

本実施の形態の変形例として、スイッチをリレーコイル7により開閉されるリレー接点8に代えて、図2に示すように、無接点の半導体素子、例えば、FET11を用いるようにしてもよい。前述のリレー(リレーコイル7&リレー接点8)は動作回路が簡単で漏れ電流が小さい特徴があるのに対して、FET11はリレーに比較して動作時間が格段に短いため、燃料電池1の急激な電圧低下でも燃料電池1に逆電圧が印加されるのを防ぐことができ、かつ、無接点スイッチであるため、接点の荒れや異物の付着がなく、半永久的に使用できる特徴がある。このFET1はS(ソース)・D(ドレイン)間がシリコンダイオード5に並列に接続されて並列回路を構成し、G(ゲート)には差動増幅器9の出力が接続されている。なお、この差動増幅器9の±入力端子は図1の場合とは逆とされている。   As a modification of the present embodiment, a contactless semiconductor element, for example, an FET 11 may be used instead of the relay contact 8 that is opened and closed by the relay coil 7 as shown in FIG. The above-described relay (relay coil 7 & relay contact 8) has a feature that the operation circuit is simple and the leakage current is small. On the other hand, the operation time of the FET 11 is much shorter than that of the relay. Since the reverse voltage can be prevented from being applied to the fuel cell 1 even when the voltage drops, and since it is a non-contact switch, there is a feature that it can be used semipermanently without any contact roughening or foreign matter adhesion. The FET 1 is connected in parallel to the silicon diode 5 between S (source) and D (drain) to form a parallel circuit, and the output of the differential amplifier 9 is connected to G (gate). The ± input terminal of the differential amplifier 9 is opposite to that in FIG.

動作的には、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より高い時は差動増幅器9の出力が、図1の場合とは逆に、H(High)になりFET11のG(ゲート)電圧がS(ソース)電圧より高くなるのでFET11がONしシリコンダイオード5のアノード、カソード間をショートする。従って、燃料電池1から電力を取り出している時はシリコンダイオード5での電圧降下はなく、ショットキーダイオード6だけの電圧降下となるので、電力損失を少なくすることができる。   In operation, when the output voltage of the fuel cell 1 is higher than the input terminal voltage of the constant voltage power supply 3, the output of the differential amplifier 9 becomes H (High), contrary to the case of FIG. Since the (gate) voltage becomes higher than the S (source) voltage, the FET 11 is turned ON, and the anode and cathode of the silicon diode 5 are short-circuited. Therefore, when power is extracted from the fuel cell 1, there is no voltage drop at the silicon diode 5, but only at the Schottky diode 6, so that power loss can be reduced.

反対に、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より低い時は差動増幅器9の出力がL(Low)になりFET11のG(ゲート)電圧がS(ソース)電圧と等しくなるのでFET11がOFFし、シリコンダイオード5のアノード、カソード間には電気的に何もないのと同じになる。従って、定電圧電源3の入力端子から燃料電池1の出力端子に逆に電流が流れようとしても耐電圧の高いシリコンダイオード5で堰き止められるので耐電圧の低いショットキーダイオード6に大きな逆電圧が印加されることはない。   On the contrary, when the output voltage of the fuel cell 1 is lower than the input terminal voltage of the constant voltage power supply 3, the output of the differential amplifier 9 becomes L (Low) and the G (gate) voltage of the FET 11 is equal to the S (source) voltage. Therefore, the FET 11 is turned OFF, and it is the same as that there is nothing electrically between the anode and the cathode of the silicon diode 5. Therefore, even if a current flows backward from the input terminal of the constant voltage power supply 3 to the output terminal of the fuel cell 1, it is blocked by the silicon diode 5 having a high withstand voltage, so that a large reverse voltage is applied to the Schottky diode 6 having a low withstand voltage. It is never applied.

また、別の変形例を図3に示す。この変形例は、ショットキーダイオード6に並列に抵抗12を接続したものである。この抵抗12は、ショットキーダイオード6に直列に接続されたシリコンダイオード5やリレー接点8の漏れ抵抗を通じて逆方向電圧がショットキーダイオード6に印加されないようにするためのものである。   Another modification is shown in FIG. In this modification, a resistor 12 is connected in parallel to the Schottky diode 6. This resistor 12 is for preventing reverse voltage from being applied to the Schottky diode 6 through the leakage resistance of the silicon diode 5 and the relay contact 8 connected in series with the Schottky diode 6.

例えば、図1に示した回路構成でシリコンダイオード5の漏れ抵抗が10MΩ、ショットキーダイオード6の漏れ抵抗100KΩ、燃料電池1の出力端子電圧が0V、定電圧電源3の入力端子電圧が100Vの時、ショットキーダイオード6に印加される逆方向電圧Vsは、
Vs=100V*100KΩ/(10MΩ+100KΩ)
から求められ、0.99Vとなる。この値はショットキーダイオード6の逆耐圧よりかなり小さいのでショットキーダイオード6に並列に抵抗12を挿入する必要は必ずしもない。しかし、漏れ抵抗は、ばらつきも大きく、環境によっても大きく変化し、また、ショットキーダイオード6の性能が向上し漏れ抵抗値が格段に向上すれば逆耐圧をオーバーすることも有り得るが、抵抗12を挿入することにより確実に防止することができる。
For example, when the leakage resistance of the silicon diode 5 is 10 MΩ, the leakage resistance of the Schottky diode 6 is 100 KΩ, the output terminal voltage of the fuel cell 1 is 0 V, and the input terminal voltage of the constant voltage power supply 3 is 100 V in the circuit configuration shown in FIG. The reverse voltage Vs applied to the Schottky diode 6 is
Vs = 100V * 100KΩ / (10MΩ + 100KΩ)
And is 0.99V. Since this value is much smaller than the reverse breakdown voltage of the Schottky diode 6, it is not always necessary to insert the resistor 12 in parallel with the Schottky diode 6. However, the leakage resistance varies greatly and varies greatly depending on the environment. If the performance of the Schottky diode 6 is improved and the leakage resistance value is significantly improved, the reverse breakdown voltage may be exceeded. By inserting, it can prevent reliably.

図4に示すように、図2に示した構成例についても、同様にショットキーダイオード6に並列に抵抗12を接続してもよい。   As shown in FIG. 4, the resistor 12 may be connected in parallel to the Schottky diode 6 in the configuration example shown in FIG.

[第二の実施の形態]
本発明の第二の実施の形態を図5に基づいて説明する。前述の図1ないし図4で示した部分と同一部分は同一符号を用いて示し、説明も省略する。基本的構成は、図1の場合に準ずるが、本実施の形態では、シリコンダイオード5とリレー接点8との並列回路に対して、リレー接点8と直列に整流素子ショットキーダイオード6を接続したものである。
[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG. The same parts as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is also omitted. The basic configuration is the same as the case of FIG. 1, but in this embodiment, a rectifier Schottky diode 6 is connected in series with the relay contact 8 with respect to the parallel circuit of the silicon diode 5 and the relay contact 8. It is.

このような構成において、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より高い時(ダイオード5,6にかかる電圧が順方向の場合)は、差動増幅器9の出力がL(Low)になりリレーコイル7に電流が流れるため、リレー接点8が閉じ、シリコンダイオード5とショットキーダイオード6との並列回路が形成される。従って、燃料電池1から電力を取り出している時は順方向の電圧降下の小さいショットキーダイオード6だけに電流が流れるので、電力損失を少なくすることができる。   In such a configuration, when the output voltage of the fuel cell 1 is higher than the input terminal voltage of the constant voltage power supply 3 (when the voltage applied to the diodes 5 and 6 is forward), the output of the differential amplifier 9 is L (Low). ) And the current flows through the relay coil 7, the relay contact 8 is closed, and a parallel circuit of the silicon diode 5 and the Schottky diode 6 is formed. Accordingly, when the power is taken out from the fuel cell 1, the current flows only through the Schottky diode 6 having a small forward voltage drop, so that the power loss can be reduced.

反対に、燃料電池1の出力電圧が定電圧電源3の入力端子電圧より低い時(ダイオード5,6にかかる電圧が逆方向の場合)は、差動増幅器9の出力がH(High)になりリレーコイル7に電流が流れないため、リレー接点8が開き、シリコンダイオード5のカソードから、ショットキーダイオード6は電気的に切り離されるので、耐電圧の低いショットキーダイオード6に大きな逆電圧が印加されることはない。   Conversely, when the output voltage of the fuel cell 1 is lower than the input terminal voltage of the constant voltage power supply 3 (when the voltage applied to the diodes 5 and 6 is in the reverse direction), the output of the differential amplifier 9 becomes H (High). Since no current flows through the relay coil 7, the relay contact 8 is opened, and the Schottky diode 6 is electrically disconnected from the cathode of the silicon diode 5, so that a large reverse voltage is applied to the Schottky diode 6 having a low withstand voltage. Never happen.

本実施の形態の変形例として、スイッチをリレーコイル7により開閉されるリレー接点8に代えて、図6に示すように、無接点の半導体素子、例えば、FET11を用いるようにしてもよい。これは、前述の図1と図2との関係の場合と同様であり、動作等については説明を省略する。   As a modification of the present embodiment, a contactless semiconductor element, for example, an FET 11 may be used instead of the relay contact 8 that is opened and closed by the relay coil 7 as shown in FIG. This is the same as in the case of the relationship between FIG. 1 and FIG. 2 described above, and the description of the operation and the like is omitted.

また、前述の図3、図4の場合と同様に、本実施の形態の場合も、別の変形例として,図7、図8に示すように、ショットキーダイオード6に並列に抵抗12を接続してもよい。   As in the case of FIG. 3 and FIG. 4 described above, in this embodiment, as another modification, a resistor 12 is connected in parallel to the Schottky diode 6 as shown in FIG. 7 and FIG. May be.

[第三の実施の形態]
本発明の第三の実施の形態を図9に基づいて説明する。本実施の形態は、前述したような構成の電源システムPSを複写機、ファクシミリ、複合機(MFP)、各種プリンタ等の画像形成装置なる電子機器用の電源として使用するようにした適用例を示す。この画像形成装置21は、画像形成部22、通信制御部23、機械駆動部24、電子制御部25、定着部26等の各々周知の各種負荷を備えるものであり、これらの各種負荷に対する電源として電源システムPSが当該画像形成装置21に内蔵される形で設けられ、インバータ回路27により適当な高電圧等に変換されて電力が供給されるように構成されている。
[Third embodiment]
A third embodiment of the present invention will be described with reference to FIG. The present embodiment shows an application example in which the power supply system PS configured as described above is used as a power supply for an electronic apparatus such as a copying machine, a facsimile machine, a multifunction peripheral (MFP), and various printers. . The image forming apparatus 21 includes various well-known loads such as an image forming unit 22, a communication control unit 23, a mechanical drive unit 24, an electronic control unit 25, and a fixing unit 26, and serves as a power source for these various loads. The power supply system PS is provided so as to be built in the image forming apparatus 21, and is configured to be supplied with electric power after being converted into an appropriate high voltage or the like by the inverter circuit 27.

なお、当該電源システムPSを備える電子機器としては、このような画像形成装置に限らず、電子黒板等の各種機器に適用し得るのはもちろんである。   Of course, the electronic apparatus provided with the power supply system PS is not limited to such an image forming apparatus, but can be applied to various apparatuses such as an electronic blackboard.

本発明の第一の実施の形態の電源システムを示す概略回路図である。It is a schematic circuit diagram which shows the power supply system of 1st embodiment of this invention. その変形例を示す概略回路図である。It is a schematic circuit diagram which shows the modification. 別の変形例を示す概略回路図である。It is a schematic circuit diagram which shows another modification. さらに別の変形例を示す概略回路図である。It is a schematic circuit diagram which shows another modification. 本発明の第二の実施の形態の電源システムを示す概略回路図である。It is a schematic circuit diagram which shows the power supply system of 2nd embodiment of this invention. その変形例を示す概略回路図である。It is a schematic circuit diagram which shows the modification. 別の変形例を示す概略回路図である。It is a schematic circuit diagram which shows another modification. さらに別の変形例を示す概略回路図である。It is a schematic circuit diagram which shows another modification. 本発明の第三の実施の形態の画像形成装置を示す概略ブロック図である。It is a schematic block diagram which shows the image forming apparatus of 3rd embodiment of this invention.

符号の説明Explanation of symbols

1 燃料電池、電池
3 定電圧電源
5 シリコンダイオード、第1の整流素子
6 ショットキーダイオード、第2の整流素子
8 スイッチ
9 制御素子
11 FET、スイッチ
12 抵抗
DESCRIPTION OF SYMBOLS 1 Fuel cell, battery 3 Constant voltage power supply 5 Silicon diode, 1st rectifier 6 Schottky diode, 2nd rectifier 8 Switch 9 Control element 11 FET, switch 12 Resistance

Claims (12)

電池或いは発電装置の出力側に定電圧電源を接続した電源システムにおいて、
前記電池或いは発電装置と前記定電圧電源との間で同一の整流方向に接続されて電気的能力の異なる複数の整流素子を備える、ことを特徴とする電源システム。
In a power supply system in which a constant voltage power supply is connected to the output side of a battery or power generator,
A power supply system comprising a plurality of rectifier elements connected in the same rectification direction between the battery or the power generation device and the constant voltage power supply and having different electrical capabilities.
燃料電池の出力側に定電圧電源を接続した電源システムにおいて、
前記燃料電池と前記定電圧電源の間で同一の整流方向に接続されて電気的能力の異なる複数の整流素子を備える、ことを特徴とする電源システム。
In a power supply system where a constant voltage power supply is connected to the output side of the fuel cell,
A power supply system comprising a plurality of rectifier elements connected in the same rectification direction between the fuel cell and the constant voltage power supply and having different electrical capabilities.
複数の前記整流素子の一つは、他の整流素子よりも電圧降下の低い電気的能力を有する整流素子である、ことを特徴とする請求項1又は2記載の電源システム。   3. The power supply system according to claim 1, wherein one of the plurality of rectifying elements is a rectifying element having an electrical capability with a lower voltage drop than other rectifying elements. 他の整流素子よりも電圧降下の低い電気的能力を有する前記整流素子は、ショットキーダイオードである、ことを特徴とする請求項3記載の電源システム。   The power supply system according to claim 3, wherein the rectifying element having an electrical capability with a lower voltage drop than other rectifying elements is a Schottky diode. 燃料電池の出力側に定電圧電源を接続した電源システムにおいて、
前記燃料電池と前記定電圧電源との間に接続された第1の整流素子とスイッチとの並列回路と、この並列回路に直列接続されて前記第1の整流素子よりも電圧降下の低い電気的能力を有する第2の整流素子と、を備えることを特徴とする電源システム。
In a power supply system where a constant voltage power supply is connected to the output side of the fuel cell,
A parallel circuit of a first rectifier element and a switch connected between the fuel cell and the constant voltage power source, and an electric circuit connected in series to the parallel circuit and having a voltage drop lower than that of the first rectifier element. A power supply system comprising: a second rectifying element having capacity.
燃料電池の出力側に定電圧電源を接続した電源システムにおいて、
前記燃料電池と前記定電圧電源との間に接続された第1の整流素子とスイッチとの並列回路と、この並列回路中で前記スイッチに直列接続されて前記第1の整流素子よりも電圧降下の低い電気的能力を有する第2の整流素子と、を備えることを特徴とする電源システム。
In a power supply system where a constant voltage power supply is connected to the output side of the fuel cell,
A parallel circuit of a first rectifying element and a switch connected between the fuel cell and the constant voltage power source, and a voltage drop than the first rectifying element connected in series to the switch in the parallel circuit And a second rectifying element having a low electrical capacity.
前記燃料電池の出力電圧より前記定電圧電源の入力端子電圧が或る値より小さくなった時に前記スイッチをONさせる制御素子を備える、ことを特徴とする請求項5又は6記載の電源システム。   The power supply system according to claim 5, further comprising a control element that turns on the switch when an input terminal voltage of the constant voltage power supply becomes smaller than a certain value from an output voltage of the fuel cell. 前記燃料電池の出力電圧より前記定電圧電源の入力端子電圧が或る値より大きくなった時に前記スイッチをOFFさせる制御素子を備える、ことを特徴とする請求項5ないし7の何れか一記載の電源システム。   The control element according to any one of claims 5 to 7, further comprising a control element that turns off the switch when an input terminal voltage of the constant voltage power source becomes larger than a certain value than an output voltage of the fuel cell. Power system. 前記スイッチは、FETである、ことを特徴とする請求項5ないし8の何れか一記載の電源システム。   The power supply system according to claim 5, wherein the switch is an FET. 前記第2の整流素子に並列接続された抵抗を備える、ことを特徴とする請求項5ないし9の何れか一記載の電源システム。   The power supply system according to any one of claims 5 to 9, further comprising a resistor connected in parallel to the second rectifier element. 請求項1ないし10の何れか一記載の電源システムを備え、当該電源システムから供給される電力で各負荷が動作することを特徴とする電子機器。   An electronic apparatus comprising the power supply system according to claim 1, wherein each load operates with electric power supplied from the power supply system. 前記電源システムを内蔵する、ことを特徴とする請求項11記載の電子機器。
The electronic device according to claim 11, wherein the power supply system is incorporated.
JP2004063860A 2004-03-08 2004-03-08 Power supply system and electronic equipment Expired - Fee Related JP4209791B2 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8773874B2 (en) 2009-06-02 2014-07-08 Toyota Jidosha Kabushiki Kaisha Power supply system and plurality parallel resonant converters having current blocking circuit
CN111381176A (en) * 2018-12-28 2020-07-07 奥特润株式会社 Device and method for controlling the measurement of the cell voltage of a fuel cell

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8773874B2 (en) 2009-06-02 2014-07-08 Toyota Jidosha Kabushiki Kaisha Power supply system and plurality parallel resonant converters having current blocking circuit
DE112009004843B4 (en) 2009-06-02 2019-01-17 Toyota Jidosha Kabushiki Kaisha Power supply system
CN111381176A (en) * 2018-12-28 2020-07-07 奥特润株式会社 Device and method for controlling the measurement of the cell voltage of a fuel cell

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