WO2013030933A1 - Fuel cell system and fuel cell vehicle - Google Patents

Fuel cell system and fuel cell vehicle Download PDF

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Publication number
WO2013030933A1
WO2013030933A1 PCT/JP2011/069485 JP2011069485W WO2013030933A1 WO 2013030933 A1 WO2013030933 A1 WO 2013030933A1 JP 2011069485 W JP2011069485 W JP 2011069485W WO 2013030933 A1 WO2013030933 A1 WO 2013030933A1
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WIPO (PCT)
Prior art keywords
fuel cell
converter
temperature
battery
cell system
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PCT/JP2011/069485
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French (fr)
Japanese (ja)
Inventor
裕 田野
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トヨタ自動車株式会社
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Priority to PCT/JP2011/069485 priority Critical patent/WO2013030933A1/en
Publication of WO2013030933A1 publication Critical patent/WO2013030933A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04858—Electric variables
    • H01M8/04865—Voltage
    • H01M8/0488—Voltage of fuel cell stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M16/00—Structural combinations of different types of electrochemical generators
    • H01M16/003—Structural combinations of different types of electrochemical generators of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers
    • H01M16/006—Structural combinations of different types of electrochemical generators of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers of fuel cells with rechargeable batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0432—Temperature; Ambient temperature
    • H01M8/04365—Temperature; Ambient temperature of other components of a fuel cell or fuel cell stacks
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a fuel cell system and a fuel cell vehicle.
  • a fuel cell vehicle in which a fuel cell that generates power by receiving a supply of reaction gas (fuel gas and oxidizing gas) is mounted on a vehicle together with a secondary battery such as a storage battery.
  • a converter for converting a DC voltage supplied from a fuel cell or a secondary battery into a larger DC voltage is generally employed.
  • the converter is designed so that the actual voltage does not exceed the withstand voltage even in a low temperature environment where the withstand voltage of the switching element is the lowest in the specification.
  • the overvoltage threshold of the boosted voltage was set to the minimum value. However, if the overvoltage threshold is set to the minimum value in advance as described above, the boosted voltage of the converter is controlled too low even in a room temperature environment, and as a result, the vehicle running performance (drivability) may be reduced. was there.
  • the present invention has been made in view of such circumstances, and an object of the present invention is to realize control at a high voltage in a normal temperature environment while suppressing an increase in manufacturing cost in a fuel cell system including a converter. .
  • a fuel cell system is a fuel cell system including a fuel cell converter provided between a fuel cell and a load device, and a temperature of cooling water for cooling the fuel cell converter. And a threshold value switching means for switching the overvoltage threshold value of the fuel cell converter.
  • the overvoltage threshold of the fuel cell converter can be switched according to the temperature of the cooling water that cools the fuel cell converter. Therefore, for example, in a low temperature environment where the temperature of the cooling water is lower than the normal temperature, the switching element can be protected by setting the overvoltage threshold of the fuel cell converter to a small value. For this reason, since it is not necessary to employ an expensive switching element having high withstand voltage performance even in a low temperature environment, an increase in manufacturing cost of the fuel cell converter (and thus the entire system) can be suppressed. In addition, when the temperature of the cooling water is normal, control at a high voltage can be realized by setting the overvoltage threshold of the fuel cell converter to a large value.
  • the battery the battery converter provided between the battery and the load device, and limit value switching for switching the boost target voltage limit value of the battery converter according to the temperature of the cooling water Means.
  • threshold switching means for switching the overvoltage threshold of the fuel cell converter in synchronization with switching of the boost target voltage limit value of the battery converter.
  • the boost target voltage limit value of the battery converter can be switched according to the temperature of the cooling water, and the overvoltage threshold value of the fuel cell converter can be switched in synchronization with the switching of the boost target voltage limit value.
  • the fuel cell vehicle according to the present invention is equipped with the fuel cell system.
  • the present invention in a fuel cell system provided with a converter, it is possible to realize control at a high voltage in a normal temperature environment while suppressing an increase in manufacturing cost.
  • FIG. 1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a graph which shows the relationship between the cooling water temperature of the fuel cell system which concerns on embodiment of this invention, and an overvoltage threshold value.
  • the fuel cell system 1 is a power generation system mounted on a fuel cell vehicle.
  • the fuel cell system 1 rotates the traction motor 5 by supplying electric power generated by the fuel cell 2 and the battery 3 to the traction motor 5 via the inverter 4.
  • the fuel cell system 1 includes an FC (fuel cell) converter 10 provided between the fuel cell 2 and the inverter 4, a battery converter 6 provided between the battery 3 and the inverter 4, and a controller for integrated control of the entire system. 7 etc.
  • the fuel cell 2 is a solid polymer electrolyte cell stack configured by stacking a plurality of single cells in series.
  • an oxidation reaction of the following formula (1) occurs in the anode electrode
  • a reduction reaction of the following formula (2) occurs in the cathode electrode
  • the fuel cell 2 as a whole has the following formula (3).
  • An electrical reaction occurs.
  • a unit cell constituting the fuel cell 2 is a separator for supplying a fuel gas and an oxidizing gas to a membrane / electrode assembly (MEA) formed by sandwiching a polymer electrolyte membrane between two electrodes, an anode electrode and a cathode electrode. It has a structure sandwiched between.
  • the fuel cell 2 is provided with a fuel gas supply system for supplying fuel gas to the anode electrode, an oxidizing gas supply system for supplying oxidizing gas to the cathode electrode, and a cooling system for supplying cooling liquid into the separator.
  • the FC converter 10 functions to control the output voltage of the fuel cell 2.
  • the FC converter 10 in the present embodiment is a multiphase converter in which four phases of a U-phase converter 11, a V-phase converter 12, a W-phase converter 13, and an X-phase converter 14 are connected in parallel.
  • the FC converter 10 uses one phase driving that uses only one phase (for example, U phase) and two phases (for example, U phase and V phase) according to the load (required power) of a load device such as the traction motor 5.
  • the drive phase can be switched such as two-phase drive, three-phase drive using three phases (for example, U phase, V phase, and W phase) and four-phase drive using all drive phases. .
  • the FC converter 10 controls the output voltage of the fuel cell 2 so as to be a voltage corresponding to the target output (voltage after boosting). Note that the output voltage (voltage after boosting) and output current of the FC converter 10 can be detected by a voltage sensor and a current sensor (not shown).
  • the types of switching elements used for each drive phase (U phase, V phase, W phase, X phase) of the FC converter 10 include, for example, a junction Schottky diode, a pin / Schottky composite diode, and a MOS barrier.
  • Diodes such as Schottky diodes, current control transistors such as bipolar junction transistors (BJT) and Darlington, thyristors such as normal thyristors and GTO (Gate Turn Off) thyristors, MOS field effect (FET) transistors, insulated gate bipolar type Examples thereof include a voltage control type transistor such as a transistor (IGBT) and an injection promotion type insulated gate transistor (IEGT). Of these, thyristors and voltage-controlled transistors are preferable.
  • a cooling device (not shown) that circulates cooling water to cool the FC converter 10 and the like, and a temperature sensor 10a that detects the temperature of the cooling water of the cooling device are provided.
  • the temperature of the cooling water detected by the temperature sensor 10a is input to the controller 7 and used for overvoltage threshold switching control described later.
  • the battery 3 is connected in parallel to the fuel cell 2 with respect to the traction motor 5 and has a function of storing surplus power and regenerative energy during regenerative braking, and at the time of load fluctuation accompanying acceleration or deceleration of the fuel cell vehicle. It functions as an energy buffer.
  • a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery can be employed.
  • the battery converter 6 fulfills the function of controlling the input voltage of the inverter 4.
  • a battery converter having a circuit configuration similar to that of the FC converter 10 can be adopted.
  • a step-up converter may be employed, but instead, a step-up / step-down converter capable of a step-up operation and a step-down operation may be employed, and the input voltage of the inverter 4 can be controlled. Any configuration can be adopted.
  • the inverter 4 can employ, for example, a PWM inverter driven by a pulse width modulation method, and converts DC power supplied from the fuel cell 2 or the battery 3 into three-phase AC power in accordance with a control command from the controller 7. Thus, the rotational torque of the traction motor 5 is controlled.
  • the traction motor 5 generates rotational torque as power for the fuel cell vehicle, and is also configured to generate regenerative power during deceleration.
  • the rotational torque of the traction motor 5 is transmitted to the tire 9 through the shaft 8a after being decelerated to a predetermined rotational speed by the reduction gear 8.
  • all devices including the traction motor 5 and the speed reduction device 8) that operate by receiving power supplied from the fuel cell 2 are collectively referred to as a load device.
  • the controller 7 is a computer system for integrated control of the fuel cell system 1 and includes, for example, a CPU, a RAM, a ROM, and the like.
  • the controller 7 receives inputs of signals (for example, a signal indicating the accelerator opening, a signal indicating the vehicle speed, a signal indicating the output current and output voltage of the fuel cell 2) supplied from various sensors, and loads the load on the load device. (Required power) is calculated.
  • the load of the load device is, for example, the total value of the vehicle traveling power and the auxiliary power.
  • Auxiliary power is the power consumed by in-vehicle auxiliaries (air compressors, hydrogen pumps, cooling water circulation pumps, etc.), and equipment required for vehicle travel (transmissions, wheel control devices, steering devices, suspension devices, etc.) Power consumed, power consumed by devices (air conditioners, lighting fixtures, audio, etc.) arranged in the passenger space are included.
  • the controller 7 determines the distribution of output power between the fuel cell 2 and the battery 3 and calculates a power generation command value.
  • the controller 7 controls the operations of the FC converter 10 and the battery converter 6 so that these required powers are obtained.
  • the controller 7 receives the input of the temperature of the cooling water detected by the temperature sensor 10a and switches the target voltage limit value (boost target voltage limit value) of the output voltage (voltage after boost) of the battery converter 6 or not.
  • the boost target voltage limit value is switched according to the detected temperature so that the boost target voltage limit value increases as the detected temperature increases. That is, the controller 7 functions as limit value switching means in the present invention.
  • the controller 7 sets the boost target voltage limit value of the battery converter 6 to V B1 (V). Keep it. Then, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B1 (V) to V B2 (V) when the detected temperature rises to T2 (° C.) or more, and detects the detected temperature. Is kept at V B2 (V) in the temperature range of T2 (° C.) or more and less than T4 (° C.) (eg, T3 (° C.)). Thereafter, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B2 (V) to V B3 (V) when the detected temperature rises to T4 (° C.) or higher.
  • the controller 7 sets the boost target voltage limit value of the battery converter 6 to V until the detected temperature decreases and becomes lower than T3 (° C.). B3 (V) is maintained. Then, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B3 (V) to V B2 (V) when the detected temperature falls below T3 (° C.), and detects the detected temperature. Is kept at V B2 (V) in the temperature range of T1 (° C.) or more and less than T3 (° C.) (eg, T2 (° C.)). Thereafter, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B2 (V) to V B1 (V) when the detected temperature falls below T1 (° C.).
  • the controller 7 receives an input of the temperature of the cooling water detected by the temperature sensor 10a, determines whether or not to switch the overvoltage threshold of the output voltage (post-boost voltage) of the FC converter 10, and the detected temperature is high.
  • the overvoltage threshold is switched according to the detected temperature so as to increase the overvoltage threshold as the time goes. That is, the controller 7 functions as threshold switching means in the present invention. At this time, the controller 7 performs control to switch the overvoltage threshold of the FC converter 10 in synchronization with the switching of the boost target voltage limit value of the battery converter 6.
  • the controller 7 when the detected temperature is lower than T2 (° C.) (for example, T1 (° C.)), the controller 7 maintains the overvoltage threshold of the FC converter 10 as V FC1 (V). To do. The controller 7 switches the overvoltage threshold of the FC converter 10 from V FC1 (V) to V FC2 (V) when the detected temperature rises to T2 (° C.) or higher, and the detected temperature is T2 ( The overvoltage threshold is maintained at V FC2 (V) in the temperature region of not less than T4 (° C) (eg, T3 (° C)). Thereafter, the controller 7 switches the overvoltage threshold of the FC converter 10 from V FC2 (V) to V FC3 (V) when the detected temperature rises to T4 (° C.) or higher.
  • the controller 7 sets the overvoltage threshold of the FC converter 10 to V FC3 (V) until the detected temperature thereafter decreases to less than T3 (° C.). ).
  • the controller 7 switches the overvoltage threshold of the FC converter 10 from V FC3 (V) to V FC2 (V) when the detected temperature falls below T3 (° C.), and the detected temperature is T1 (
  • the overvoltage threshold is maintained as V FC2 (V) in the temperature region of not less than T 3 (° C.) (eg, T 2 (° C.)).
  • the controller 7 switches the overvoltage threshold value of the FC converter 10 from V FC2 (V) to V FC1 (V) when the detected temperature falls below T1 (° C.).
  • the boost target voltage limit value of the battery converter 6 and the overvoltage threshold of the FC converter 10 are V B1 ( V) and V FC1 (V) are maintained, and when the detected temperature reaches T2 (° C.) or more, the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B2 (V), respectively. And V FC2 (V) at the same time.
  • the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B2 (V).
  • V FC2 (V) and when the detected temperature reaches T4 (° C.) or higher, the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B3 (V) and V V, respectively. It will be switched simultaneously to FC3 (V).
  • the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B3 (V) and V FC3 (V), respectively, until the detected temperature becomes lower than T3 (° C.).
  • the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 become V B2 (V) and V FC2 (V), respectively. It can be switched at the same time.
  • the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B2 (V).
  • V FC2 (V) and when the detected temperature becomes less than T1 (° C.), the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B1 (V) and V FC1, respectively. Switching to (V) is performed at the same time.
  • the overvoltage threshold of the FC converter 10 can be switched according to the temperature of the cooling water that cools the FC converter 10 and the like. Therefore, in a low temperature environment where the temperature of the cooling water is lower than room temperature (for example, less than T2 (° C.)), the switching element is set by setting the overvoltage threshold of the FC converter 10 to a small value (V FC1 (V)). Can be protected. For this reason, since it is not necessary to employ an expensive switching element having a high withstand voltage performance even in a low temperature environment, an increase in manufacturing cost of the FC converter 10 (and thus the entire system) can be suppressed. Further, when the temperature of the cooling water is normal temperature (for example, T4 (° C.)), the overvoltage threshold of the FC converter 10 is set to a large value (V FC3 (V)), thereby realizing a high voltage control. Can be made.
  • the boost target voltage limit value of the battery converter 6 can be switched according to the temperature of the cooling water, and is synchronized with the switching of the boost target voltage limit value.
  • the overvoltage threshold of the FC converter 10 can be switched.
  • the fuel cell vehicle according to the embodiment described above sets the overvoltage threshold of the FC converter 10 to a large value (V FC3 (V)) when the temperature of the cooling water is normal temperature (for example, T4 (° C.)).
  • V FC3 (V) the temperature of the cooling water is normal temperature (for example, T4 (° C.)).
  • the fuel cell system according to the present invention is mounted on a fuel cell vehicle.
  • a fuel cell system can also be mounted.
  • the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for a building (house, building, etc.).
  • the present invention can be applied to a portable fuel cell system.
  • SYMBOLS 1 Fuel cell system, 2 ... Fuel cell, 3 ... Battery, 5 ... Traction motor (load apparatus), 6 ... Battery converter, 7 ... Controller (threshold value switching means, limit value switching means), 10 ... FC converter (fuel cell) converter).

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Abstract

[Problem] A fuel cell system provided with a converter, wherein control at a high voltage in a normal-temperature environment is achieved while an increase in manufacturing cost is suppressed. [Solution] A fuel cell system (1) having a fuel cell converter (10) provided between a fuel cell (2) and a load device (5), wherein the fuel cell system is provided with a threshold value switching means (7) for switching the overvoltage threshold value of the fuel cell converter (10) according to the temperature of the cooling water cooling the fuel cell converter (10). The threshold value switching means (7) increases the overvoltage threshold value as the temperature of the cooling water increases.

Description

燃料電池システム及び燃料電池車両Fuel cell system and fuel cell vehicle
　本発明は、燃料電池システム及び燃料電池車両に関する。 The present invention relates to a fuel cell system and a fuel cell vehicle.
　従来より、反応ガス（燃料ガス及び酸化ガス）の供給を受けて発電を行う燃料電池を蓄電池等の二次電池とともに車両に搭載した燃料電池車両が提案されている。このような燃料電池車両においては、燃料電池や二次電池から供給される直流電圧をより大きい直流電圧に変換するためのコンバータが採用されるのが一般的である。 Conventionally, there has been proposed a fuel cell vehicle in which a fuel cell that generates power by receiving a supply of reaction gas (fuel gas and oxidizing gas) is mounted on a vehicle together with a secondary battery such as a storage battery. In such a fuel cell vehicle, a converter for converting a DC voltage supplied from a fuel cell or a secondary battery into a larger DC voltage is generally employed.
　現在においては、コンバータのスイッチング素子の温度を検出し、検出された素子温度に基づいてスイッチング素子の駆動数及び駆動対象スイッチング素子を決定する技術が提案されている（例えば、特許文献１参照）。このような技術を採用すると、低負荷時にまで全てのスイッチング素子を駆動させるという無駄な動作（スイッチング損失）をなくし、コンバータの電力変換効率を向上させることができる、とされている。 Currently, a technique has been proposed in which the temperature of a switching element of a converter is detected, and the number of switching elements to be driven and the switching target switching element are determined based on the detected element temperature (see, for example, Patent Document 1). By adopting such a technique, it is said that the useless operation (switching loss) of driving all the switching elements even when the load is low can be eliminated, and the power conversion efficiency of the converter can be improved.
特開２０１１－１９３３８号公報JP 2011-19338 A
　ところで、コンバータのスイッチング素子は、温度変化に伴って耐電圧性能が変化することが知られている。このため、特許文献１に記載されたような従来の技術においては、仕様上最もスイッチング素子の耐電圧が低くなるような低温環境下においても実際の電圧が耐電圧を超えないように、コンバータの昇圧後電圧の過電圧閾値を最小値に設定していた。しかし、このように過電圧閾値を予め最小値に設定すると、常温環境下においてもコンバータの昇圧後電圧を過剰に低く制御してしまい、この結果、車両走行性能（ドライバビリティ）を低下させてしまう虞があった。 By the way, it is known that the withstand voltage performance of the switching element of the converter changes as the temperature changes. For this reason, in the conventional technique as described in Patent Document 1, the converter is designed so that the actual voltage does not exceed the withstand voltage even in a low temperature environment where the withstand voltage of the switching element is the lowest in the specification. The overvoltage threshold of the boosted voltage was set to the minimum value. However, if the overvoltage threshold is set to the minimum value in advance as described above, the boosted voltage of the converter is controlled too low even in a room temperature environment, and as a result, the vehicle running performance (drivability) may be reduced. was there.
　一方、車両走行性能が低下しない程度の高い電圧での制御を低温環境下において許容するような高い耐電圧性能を有する高価なスイッチング素子を採用することもできる。しかし、このように高価なスイッチング素子を採用すると、コンバータ（ひいてはシステム全体）の製造コストが上昇してしまうという新たな問題が発生することとなる。 On the other hand, it is also possible to employ an expensive switching element having a high withstand voltage performance that allows control at a high voltage that does not deteriorate the vehicle running performance in a low temperature environment. However, when such an expensive switching element is employed, a new problem arises that the manufacturing cost of the converter (and thus the entire system) increases.
　本発明は、かかる事情に鑑みてなされたものであり、コンバータを備えた燃料電池システムにおいて、製造コストの上昇を抑制しつつ、常温環境下において高い電圧での制御を実現させることを目的とする。 The present invention has been made in view of such circumstances, and an object of the present invention is to realize control at a high voltage in a normal temperature environment while suppressing an increase in manufacturing cost in a fuel cell system including a converter. .
　前記目的を達成するため、本発明に係る燃料電池システムは、燃料電池と負荷装置との間に設けられた燃料電池コンバータを備える燃料電池システムであって、燃料電池コンバータを冷却する冷却水の温度に応じて燃料電池コンバータの過電圧閾値を切り替える閾値切替手段を備えるものである。 In order to achieve the above object, a fuel cell system according to the present invention is a fuel cell system including a fuel cell converter provided between a fuel cell and a load device, and a temperature of cooling water for cooling the fuel cell converter. And a threshold value switching means for switching the overvoltage threshold value of the fuel cell converter.
　かかる構成を採用すると、燃料電池コンバータを冷却する冷却水の温度に応じて、燃料電池コンバータの過電圧閾値を切り替えることができる。従って、例えば、冷却水の温度が常温よりも低い低温環境下においては、燃料電池コンバータの過電圧閾値を小さい値に設定することにより、スイッチング素子を保護することができる。このため、低温環境下においても高い耐電圧性能を有する高価なスイッチング素子を採用する必要がないため、燃料電池コンバータ（ひいてはシステム全体）の製造コストの上昇を抑制することができる。また、冷却水の温度が常温である場合には、燃料電池コンバータの過電圧閾値を大きい値に設定することにより、高い電圧での制御を実現させることができる。 When such a configuration is adopted, the overvoltage threshold of the fuel cell converter can be switched according to the temperature of the cooling water that cools the fuel cell converter. Therefore, for example, in a low temperature environment where the temperature of the cooling water is lower than the normal temperature, the switching element can be protected by setting the overvoltage threshold of the fuel cell converter to a small value. For this reason, since it is not necessary to employ an expensive switching element having high withstand voltage performance even in a low temperature environment, an increase in manufacturing cost of the fuel cell converter (and thus the entire system) can be suppressed. In addition, when the temperature of the cooling water is normal, control at a high voltage can be realized by setting the overvoltage threshold of the fuel cell converter to a large value.
　また、本発明に係る燃料電池システムにおいて、バッテリと、このバッテリと負荷装置との間に設けられたバッテリコンバータと、冷却水の温度に応じてバッテリコンバータの昇圧目標電圧制限値を切り替える制限値切替手段と、を備えることができる。かかる場合において、バッテリコンバータの昇圧目標電圧制限値の切替と同期させて燃料電池コンバータの過電圧閾値を切り替える閾値切替手段を採用することができる。 Further, in the fuel cell system according to the present invention, the battery, the battery converter provided between the battery and the load device, and limit value switching for switching the boost target voltage limit value of the battery converter according to the temperature of the cooling water Means. In such a case, it is possible to employ threshold switching means for switching the overvoltage threshold of the fuel cell converter in synchronization with switching of the boost target voltage limit value of the battery converter.
　かかる構成を採用すると、冷却水の温度に応じてバッテリコンバータの昇圧目標電圧制限値を切り替えることができ、この昇圧目標電圧制限値の切替と同期させて燃料電池コンバータの過電圧閾値を切り替えることができる。 If such a configuration is adopted, the boost target voltage limit value of the battery converter can be switched according to the temperature of the cooling water, and the overvoltage threshold value of the fuel cell converter can be switched in synchronization with the switching of the boost target voltage limit value. .
　また、本発明に係る燃料電池車両は、前記燃料電池システムを搭載したものである。 The fuel cell vehicle according to the present invention is equipped with the fuel cell system.
　かかる構成を採用すると、冷却水の温度が常温である場合には、燃料電池コンバータの過電圧閾値を大きい値に設定することにより、高い電圧での制御を実現させることができる。この結果、高い走行性能を確保することができる。 When such a configuration is adopted, when the temperature of the cooling water is normal, control at a high voltage can be realized by setting the overvoltage threshold of the fuel cell converter to a large value. As a result, high running performance can be ensured.
　本発明によれば、コンバータを備えた燃料電池システムにおいて、製造コストの上昇を抑制しつつ、常温環境下において高い電圧での制御を実現させることが可能となる。 According to the present invention, in a fuel cell system provided with a converter, it is possible to realize control at a high voltage in a normal temperature environment while suppressing an increase in manufacturing cost.
本発明の実施形態に係る燃料電池システムの構成図である。1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. 本発明の実施形態に係る燃料電池システムの冷却水温度と過電圧閾値との関係を示すグラフである。It is a graph which shows the relationship between the cooling water temperature of the fuel cell system which concerns on embodiment of this invention, and an overvoltage threshold value.
　以下、図面を参照して、本発明の実施形態に係る燃料電池システム１について説明する。本実施形態に係る燃料電池システム１は、燃料電池車両に搭載された発電システムである。 Hereinafter, a fuel cell system 1 according to an embodiment of the present invention will be described with reference to the drawings. The fuel cell system 1 according to the present embodiment is a power generation system mounted on a fuel cell vehicle.
　燃料電池システム１は、図１に示すように、燃料電池２やバッテリ３で発生させた電力を、インバータ４を介してトラクションモータ５に供給することにより、トラクションモータ５を回転駆動するものである。燃料電池システム１は、燃料電池２とインバータ４との間に設けられたＦＣ（燃料電池）コンバータ１０、バッテリ３とインバータ４との間に設けられたバッテリコンバータ６、システム全体を統合制御するコントローラ７等を備えている。 As shown in FIG. 1, the fuel cell system 1 rotates the traction motor 5 by supplying electric power generated by the fuel cell 2 and the battery 3 to the traction motor 5 via the inverter 4. . The fuel cell system 1 includes an FC (fuel cell) converter 10 provided between the fuel cell 2 and the inverter 4, a battery converter 6 provided between the battery 3 and the inverter 4, and a controller for integrated control of the entire system. 7 etc.
　燃料電池２は、複数の単電池を直列に積層して構成した固体高分子電解質型セルスタックである。燃料電池２においては、アノード電極において以下の（１）式の酸化反応が生じ、カソード電極において以下の（２）式の還元反応が生じ、燃料電池２全体としては以下の（３）式の起電反応が生じる。 The fuel cell 2 is a solid polymer electrolyte cell stack configured by stacking a plurality of single cells in series. In the fuel cell 2, an oxidation reaction of the following formula (1) occurs in the anode electrode, and a reduction reaction of the following formula (2) occurs in the cathode electrode, and the fuel cell 2 as a whole has the following formula (3). An electrical reaction occurs.
　Ｈ２→２Ｈ＋＋２ｅ－　・・・（１）
　（１／２）Ｏ２＋２Ｈ＋＋２ｅ－→Ｈ２Ｏ　・・・（２）
　Ｈ２＋（１／２）Ｏ２→Ｈ２Ｏ　・・・（３） H 2 → 2H + + 2e − (1)
(1/2) O 2 + 2H + + 2e − → H 2 O (2)
H 2 + (1/2) O 2 → H 2 O (3)
　燃料電池２を構成する単電池は、高分子電解質膜をアノード電極及びカソード電極の二つの電極で挟み込んで構成した膜・電極接合体（ＭＥＡ）を、燃料ガス及び酸化ガスを供給するためのセパレータで挟み込んだ構造を有している。燃料電池２には、燃料ガスをアノード電極に供給する燃料ガス供給系統、酸化ガスをカソード電極に供給する酸化ガス供給系統、冷却液をセパレータ内に供給する冷却系統が設けられており、コントローラ７からの制御信号に応じて燃料ガスの供給量や酸化ガスの供給量が制御されることにより、所望の電力を発生させることができるようになっている。 A unit cell constituting the fuel cell 2 is a separator for supplying a fuel gas and an oxidizing gas to a membrane / electrode assembly (MEA) formed by sandwiching a polymer electrolyte membrane between two electrodes, an anode electrode and a cathode electrode. It has a structure sandwiched between. The fuel cell 2 is provided with a fuel gas supply system for supplying fuel gas to the anode electrode, an oxidizing gas supply system for supplying oxidizing gas to the cathode electrode, and a cooling system for supplying cooling liquid into the separator. By controlling the supply amount of the fuel gas and the supply amount of the oxidizing gas in accordance with the control signal from the control signal, it is possible to generate desired power.
　ＦＣコンバータ１０は、燃料電池２の出力電圧を制御する機能を果たす。本実施形態におけるＦＣコンバータ１０は、図１に示すように、Ｕ相コンバータ１１、Ｖ相コンバータ１２、Ｗ相コンバータ１３、Ｘ相コンバータ１４の４相を並列に接続した多相コンバータである。ＦＣコンバータ１０は、トラクションモータ５等の負荷装置の負荷（要求電力）に応じて、１相（例えばＵ相）のみを使用する１相駆動、２相（例えばＵ相とＶ相）を使用する２相駆動、３相（例えばＵ相とＶ相とＷ相）を使用する３相駆動、全ての駆動相を使用する４相駆動、といった駆動相の切替えを行うことができるようになっている。 The FC converter 10 functions to control the output voltage of the fuel cell 2. As shown in FIG. 1, the FC converter 10 in the present embodiment is a multiphase converter in which four phases of a U-phase converter 11, a V-phase converter 12, a W-phase converter 13, and an X-phase converter 14 are connected in parallel. The FC converter 10 uses one phase driving that uses only one phase (for example, U phase) and two phases (for example, U phase and V phase) according to the load (required power) of a load device such as the traction motor 5. The drive phase can be switched such as two-phase drive, three-phase drive using three phases (for example, U phase, V phase, and W phase) and four-phase drive using all drive phases. .
　ＦＣコンバータ１０は、燃料電池２の出力電圧を目標出力に応じた電圧（昇圧後電圧）となるように制御する。なお、ＦＣコンバータ１０の出力電圧（昇圧後電圧）や出力電流は、図示していない電圧センサ及び電流センサにより検出することができるようになっている。 The FC converter 10 controls the output voltage of the fuel cell 2 so as to be a voltage corresponding to the target output (voltage after boosting). Note that the output voltage (voltage after boosting) and output current of the FC converter 10 can be detected by a voltage sensor and a current sensor (not shown).
　ＦＣコンバータ１０の各駆動相（Ｕ相、Ｖ相、Ｗ相、Ｘ相）に用いられるスイッチング素子の種類としては、例えば、接合ショットキーダイオード、ｐ－ｉ－ｎ／ショットキー複合ダイオード、ＭＯＳ障壁ショットキーダイオード等のダイオード類、バイポーラ接合型トランジスタ（ＢＪＴ）やダーリントンといった電流制御型トランジスタ、通常サイリスタやＧＴＯ（Gate Turn Off）サイリスタ等のサイリスタ類、ＭＯＳ電界効果（ＦＥＴ）トランジスタ、絶縁ゲートバイポーラ型トランジスタ（ＩＧＢＴ）、注入促進型絶縁ゲートトランジスタ（ＩＥＧＴ）等の電圧制御型トランジスタ、等を挙げることができる。これらの中では、サイリスタ類及び電圧制御型トランジスタが好ましい。 The types of switching elements used for each drive phase (U phase, V phase, W phase, X phase) of the FC converter 10 include, for example, a junction Schottky diode, a pin / Schottky composite diode, and a MOS barrier. Diodes such as Schottky diodes, current control transistors such as bipolar junction transistors (BJT) and Darlington, thyristors such as normal thyristors and GTO (Gate Turn Off) thyristors, MOS field effect (FET) transistors, insulated gate bipolar type Examples thereof include a voltage control type transistor such as a transistor (IGBT) and an injection promotion type insulated gate transistor (IEGT). Of these, thyristors and voltage-controlled transistors are preferable.
　本実施形態においては、冷却水を循環させてＦＣコンバータ１０等を冷却する図示されていない冷却装置と、この冷却装置の冷却水の温度を検出する温度センサ１０ａと、が設けられている。温度センサ１０ａで検出された冷却水の温度はコントローラ７に入力され、後述する過電圧閾値の切替制御に用いられる。 In the present embodiment, a cooling device (not shown) that circulates cooling water to cool the FC converter 10 and the like, and a temperature sensor 10a that detects the temperature of the cooling water of the cooling device are provided. The temperature of the cooling water detected by the temperature sensor 10a is input to the controller 7 and used for overvoltage threshold switching control described later.
　バッテリ３は、トラクションモータ５に対して燃料電池２と並列に接続されており、余剰電力や回生制動時の回生エネルギを蓄える機能を有するとともに、燃料電池車両の加速又は減速に伴う負荷変動時のエネルギーバッファとして機能するものである。バッテリ３としては、例えば、ニッケル・カドミウム蓄電池、ニッケル・水素蓄電池、リチウム二次電池等の二次電池を採用することができる。 The battery 3 is connected in parallel to the fuel cell 2 with respect to the traction motor 5 and has a function of storing surplus power and regenerative energy during regenerative braking, and at the time of load fluctuation accompanying acceleration or deceleration of the fuel cell vehicle. It functions as an energy buffer. As the battery 3, for example, a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery can be employed.
　バッテリコンバータ６は、インバータ４の入力電圧を制御する機能を果たすものであり、例えばＦＣコンバータ１０と同様の回路構成を有するものを採用することができる。バッテリコンバータ６としては、昇圧型のコンバータを採用してもよいが、これに代えて昇圧動作及び降圧動作が可能な昇降圧型のコンバータを採用してもよく、インバータ４の入力電圧の制御が可能なあらゆる構成を採用することができる。 The battery converter 6 fulfills the function of controlling the input voltage of the inverter 4. For example, a battery converter having a circuit configuration similar to that of the FC converter 10 can be adopted. As the battery converter 6, a step-up converter may be employed, but instead, a step-up / step-down converter capable of a step-up operation and a step-down operation may be employed, and the input voltage of the inverter 4 can be controlled. Any configuration can be adopted.
　インバータ４は、例えばパルス幅変調方式で駆動されるＰＷＭインバータを採用することができ、コントローラ７からの制御指令に従って、燃料電池２やバッテリ３から供給される直流電力を三相交流電力に変換して、トラクションモータ５の回転トルクを制御する。 The inverter 4 can employ, for example, a PWM inverter driven by a pulse width modulation method, and converts DC power supplied from the fuel cell 2 or the battery 3 into three-phase AC power in accordance with a control command from the controller 7. Thus, the rotational torque of the traction motor 5 is controlled.
　トラクションモータ５は、燃料電池車両の動力となる回転トルクを発生させるものであり、減速時には回生電力を発生させるようにも構成されている。トラクションモータ５の回転トルクは、減速装置８によって所定の回転数に減速させられた上で、シャフト８ａを介してタイヤ９に伝達される。なお、本実施形態においては、燃料電池２から供給される電力を受けて作動する全ての機器（トラクションモータ５及び減速装置８を含む）を負荷装置と総称することとする。 The traction motor 5 generates rotational torque as power for the fuel cell vehicle, and is also configured to generate regenerative power during deceleration. The rotational torque of the traction motor 5 is transmitted to the tire 9 through the shaft 8a after being decelerated to a predetermined rotational speed by the reduction gear 8. In the present embodiment, all devices (including the traction motor 5 and the speed reduction device 8) that operate by receiving power supplied from the fuel cell 2 are collectively referred to as a load device.
　コントローラ７は、燃料電池システム１を統合制御するためのコンピュータシステムであり、例えばＣＰＵ、ＲＡＭ、ＲＯＭ等を有している。コントローラ７は、各種センサから供給される信号（例えば、アクセル開度を表す信号、車速を表す信号、燃料電池２の出力電流や出力電圧を表す信号等）の入力を受けて、負荷装置の負荷（要求電力）を算出する。 The controller 7 is a computer system for integrated control of the fuel cell system 1 and includes, for example, a CPU, a RAM, a ROM, and the like. The controller 7 receives inputs of signals (for example, a signal indicating the accelerator opening, a signal indicating the vehicle speed, a signal indicating the output current and output voltage of the fuel cell 2) supplied from various sensors, and loads the load on the load device. (Required power) is calculated.
　負荷装置の負荷は、例えば車両走行電力と補機電力との合計値である。補機電力には、車載補機類（エアコンプレッサ、水素ポンプ、冷却水循環ポンプ等）で消費される電力、車両走行に必要な装置（変速機、車輪制御装置、操舵装置、懸架装置等）で消費される電力、乗員空間内に配置される装置（空調装置、照明器具、オーディオ等）で消費される電力、等が含まれる。 The load of the load device is, for example, the total value of the vehicle traveling power and the auxiliary power. Auxiliary power is the power consumed by in-vehicle auxiliaries (air compressors, hydrogen pumps, cooling water circulation pumps, etc.), and equipment required for vehicle travel (transmissions, wheel control devices, steering devices, suspension devices, etc.) Power consumed, power consumed by devices (air conditioners, lighting fixtures, audio, etc.) arranged in the passenger space are included.
　そして、コントローラ７は、燃料電池２とバッテリ３との各々の出力電力の配分を決定し、発電指令値を算出する。コントローラ７は、燃料電池２及びバッテリ３に対する要求電力を算出すると、これらの要求電力が得られるようにＦＣコンバータ１０及びバッテリコンバータ６の動作を制御する。 Then, the controller 7 determines the distribution of output power between the fuel cell 2 and the battery 3 and calculates a power generation command value. When the controller 7 calculates the required power for the fuel cell 2 and the battery 3, the controller 7 controls the operations of the FC converter 10 and the battery converter 6 so that these required powers are obtained.
　また、コントローラ７は、温度センサ１０ａで検出された冷却水の温度の入力を受けて、バッテリコンバータ６の出力電圧（昇圧後電圧）の目標電圧制限値（昇圧目標電圧制限値）を切り替えるか否かを判定し、検出温度が高くなるに従って昇圧目標電圧制限値を大きくするように検出温度に応じて昇圧目標電圧制限値を切り替える。すなわち、コントローラ７は、本発明における制限値切替手段として機能する。 Further, the controller 7 receives the input of the temperature of the cooling water detected by the temperature sensor 10a and switches the target voltage limit value (boost target voltage limit value) of the output voltage (voltage after boost) of the battery converter 6 or not. The boost target voltage limit value is switched according to the detected temperature so that the boost target voltage limit value increases as the detected temperature increases. That is, the controller 7 functions as limit value switching means in the present invention.
　具体的には、コントローラ７は、図２に示すように、検出温度がＴ２（℃）未満（例えばＴ１（℃））であるときには、バッテリコンバータ６の昇圧目標電圧制限値をＶＢ１（Ｖ）のまま維持する。そして、コントローラ７は、検出温度が上昇してＴ２（℃）以上となった時点で、バッテリコンバータ６の昇圧目標電圧制限値をＶＢ１（Ｖ）からＶＢ２（Ｖ）へと切り替え、検出温度がＴ２（℃）以上Ｔ４（℃）未満（例えばＴ３（℃））の温度領域において昇圧目標電圧制限値をＶＢ２（Ｖ）のまま維持する。その後、コントローラ７は、検出温度が上昇してＴ４（℃）以上となった時点でバッテリコンバータ６の昇圧目標電圧制限値をＶＢ２（Ｖ）からＶＢ３（Ｖ）へと切り替える。 Specifically, as shown in FIG. 2, when the detected temperature is lower than T2 (° C.) (eg, T1 (° C.)), the controller 7 sets the boost target voltage limit value of the battery converter 6 to V B1 (V). Keep it. Then, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B1 (V) to V B2 (V) when the detected temperature rises to T2 (° C.) or more, and detects the detected temperature. Is kept at V B2 (V) in the temperature range of T2 (° C.) or more and less than T4 (° C.) (eg, T3 (° C.)). Thereafter, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B2 (V) to V B3 (V) when the detected temperature rises to T4 (° C.) or higher.
　一方、コントローラ７は、検出温度が上昇してＴ４（℃）以上となった場合においては、その後検出温度が下降してＴ３（℃）未満となるまでバッテリコンバータ６の昇圧目標電圧制限値をＶＢ３（Ｖ）のまま維持する。そして、コントローラ７は、検出温度が下降してＴ３（℃）未満となった時点で、バッテリコンバータ６の昇圧目標電圧制限値をＶＢ３（Ｖ）からＶＢ２（Ｖ）へと切り替え、検出温度がＴ１（℃）以上Ｔ３（℃）未満（例えばＴ２（℃））の温度領域において昇圧目標電圧制限値をＶＢ２（Ｖ）のまま維持する。その後、コントローラ７は、検出温度が下降してＴ１（℃）未満となった時点でバッテリコンバータ６の昇圧目標電圧制限値をＶＢ２（Ｖ）からＶＢ１（Ｖ）へと切り替える。 On the other hand, when the detected temperature rises to be equal to or higher than T4 (° C.), the controller 7 sets the boost target voltage limit value of the battery converter 6 to V until the detected temperature decreases and becomes lower than T3 (° C.). B3 (V) is maintained. Then, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B3 (V) to V B2 (V) when the detected temperature falls below T3 (° C.), and detects the detected temperature. Is kept at V B2 (V) in the temperature range of T1 (° C.) or more and less than T3 (° C.) (eg, T2 (° C.)). Thereafter, the controller 7 switches the boost target voltage limit value of the battery converter 6 from V B2 (V) to V B1 (V) when the detected temperature falls below T1 (° C.).
　また、コントローラ７は、温度センサ１０ａで検出された冷却水の温度の入力を受けて、ＦＣコンバータ１０の出力電圧（昇圧後電圧）の過電圧閾値を切り替えるか否かを判定し、検出温度が高くなるに従って過電圧閾値を大きくするように検出温度に応じて過電圧閾値を切り替える。すなわち、コントローラ７は、本発明における閾値切替手段として機能する。この際、コントローラ７は、バッテリコンバータ６の昇圧目標電圧制限値の切替と同期させて、ＦＣコンバータ１０の過電圧閾値を切り替えるような制御を行う。 Further, the controller 7 receives an input of the temperature of the cooling water detected by the temperature sensor 10a, determines whether or not to switch the overvoltage threshold of the output voltage (post-boost voltage) of the FC converter 10, and the detected temperature is high. The overvoltage threshold is switched according to the detected temperature so as to increase the overvoltage threshold as the time goes. That is, the controller 7 functions as threshold switching means in the present invention. At this time, the controller 7 performs control to switch the overvoltage threshold of the FC converter 10 in synchronization with the switching of the boost target voltage limit value of the battery converter 6.
　具体的には、コントローラ７は、図２に示すように、検出温度がＴ２（℃）未満（例えばＴ１（℃））であるときには、ＦＣコンバータ１０の過電圧閾値をＶＦＣ１（Ｖ）のまま維持する。そして、コントローラ７は、検出温度が上昇してＴ２（℃）以上となった時点で、ＦＣコンバータ１０の過電圧閾値をＶＦＣ１（Ｖ）からＶＦＣ２（Ｖ）へと切り替え、検出温度がＴ２（℃）以上Ｔ４（℃）未満（例えばＴ３（℃））の温度領域において過電圧閾値をＶＦＣ２（Ｖ）のまま維持する。その後、コントローラ７は、検出温度が上昇してＴ４（℃）以上となった時点でＦＣコンバータ１０の過電圧閾値をＶＦＣ２（Ｖ）からＶＦＣ３（Ｖ）へと切り替える。 Specifically, as shown in FIG. 2, when the detected temperature is lower than T2 (° C.) (for example, T1 (° C.)), the controller 7 maintains the overvoltage threshold of the FC converter 10 as V FC1 (V). To do. The controller 7 switches the overvoltage threshold of the FC converter 10 from V FC1 (V) to V FC2 (V) when the detected temperature rises to T2 (° C.) or higher, and the detected temperature is T2 ( The overvoltage threshold is maintained at V FC2 (V) in the temperature region of not less than T4 (° C) (eg, T3 (° C)). Thereafter, the controller 7 switches the overvoltage threshold of the FC converter 10 from V FC2 (V) to V FC3 (V) when the detected temperature rises to T4 (° C.) or higher.
　一方、コントローラ７は、検出温度が上昇してＴ４（℃）以上となった場合においては、その後検出温度が下降してＴ３（℃）未満となるまでＦＣコンバータ１０の過電圧閾値をＶＦＣ３（Ｖ）のまま維持する。そして、コントローラ７は、検出温度が下降してＴ３（℃）未満となった時点で、ＦＣコンバータ１０の過電圧閾値をＶＦＣ３（Ｖ）からＶＦＣ２（Ｖ）へと切り替え、検出温度がＴ１（℃）以上Ｔ３（℃）未満（例えばＴ２（℃））の温度領域において過電圧閾値をＶＦＣ２（Ｖ）のまま維持する。その後、コントローラ７は、検出温度が下降してＴ１（℃）未満となった時点でＦＣコンバータ１０の過電圧閾値をＶＦＣ２（Ｖ）からＶＦＣ１（Ｖ）へと切り替える。 On the other hand, when the detected temperature rises to be equal to or higher than T4 (° C.), the controller 7 sets the overvoltage threshold of the FC converter 10 to V FC3 (V) until the detected temperature thereafter decreases to less than T3 (° C.). ). The controller 7 switches the overvoltage threshold of the FC converter 10 from V FC3 (V) to V FC2 (V) when the detected temperature falls below T3 (° C.), and the detected temperature is T1 ( The overvoltage threshold is maintained as V FC2 (V) in the temperature region of not less than T 3 (° C.) (eg, T 2 (° C.)). Thereafter, the controller 7 switches the overvoltage threshold value of the FC converter 10 from V FC2 (V) to V FC1 (V) when the detected temperature falls below T1 (° C.).
　すなわち、検出温度の上昇過程においては、検出温度がＴ２（℃）未満（例えばＴ１（℃））であるときにバッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ１（Ｖ）及びＶＦＣ１（Ｖ）のまま維持され、検出温度がＴ２（℃）以上となった時点で、バッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ２（Ｖ）及びＶＦＣ２（Ｖ）へと同時に切り替えられる。そして、検出温度がＴ２（℃）以上Ｔ４（℃）未満（例えばＴ３（℃））の温度領域において、バッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ２（Ｖ）及びＶＦＣ２（Ｖ）のまま維持され、検出温度がＴ４（℃）以上となった時点で、バッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ３（Ｖ）及びＶＦＣ３（Ｖ）へと同時に切替えられることとなる。 That is, in the process of increasing the detected temperature, when the detected temperature is less than T2 (° C.) (for example, T1 (° C.)), the boost target voltage limit value of the battery converter 6 and the overvoltage threshold of the FC converter 10 are V B1 ( V) and V FC1 (V) are maintained, and when the detected temperature reaches T2 (° C.) or more, the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B2 (V), respectively. And V FC2 (V) at the same time. In the temperature region where the detected temperature is T2 (° C.) or higher and lower than T4 (° C.) (eg, T3 (° C.)), the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B2 (V). And V FC2 (V), and when the detected temperature reaches T4 (° C.) or higher, the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B3 (V) and V V, respectively. It will be switched simultaneously to FC3 (V).
　一方、検出温度の下降過程においては、検出温度がＴ３（℃）未満となるまでバッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ３（Ｖ）及びＶＦＣ３（Ｖ）のまま維持され、検出温度がＴ３（℃）未満となった時点で、バッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ２（Ｖ）及びＶＦＣ２（Ｖ）へと同時に切り替えられる。そして、検出温度がＴ１（℃）以上Ｔ３（℃）未満（例えばＴ２（℃））の温度領域において、バッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ２（Ｖ）及びＶＦＣ２（Ｖ）のまま維持され、検出温度がＴ１（℃）未満となった時点でバッテリコンバータ６の昇圧目標電圧制限値及びＦＣコンバータ１０の過電圧閾値が各々ＶＢ１（Ｖ）及びＶＦＣ１（Ｖ）へと同時に切替えられることとなる。 On the other hand, in the decreasing process of the detected temperature, the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B3 (V) and V FC3 (V), respectively, until the detected temperature becomes lower than T3 (° C.). When the detected temperature becomes less than T3 (° C.), the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 become V B2 (V) and V FC2 (V), respectively. It can be switched at the same time. In the temperature region where the detected temperature is T1 (° C.) or more and less than T3 (° C.) (eg, T2 (° C.)), the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B2 (V). And V FC2 (V), and when the detected temperature becomes less than T1 (° C.), the boost target voltage limit value of the battery converter 6 and the overvoltage threshold value of the FC converter 10 are V B1 (V) and V FC1, respectively. Switching to (V) is performed at the same time.
　以上説明した実施形態に係る燃料電池システム１においては、ＦＣコンバータ１０等を冷却する冷却水の温度に応じて、ＦＣコンバータ１０の過電圧閾値を切り替えることができる。従って、冷却水の温度が常温よりも低い低温環境下（例えばＴ２（℃）未満）においては、ＦＣコンバータ１０の過電圧閾値を小さい値（ＶＦＣ１（Ｖ））に設定することにより、スイッチング素子を保護することができる。このため、低温環境下においても高い耐電圧性能を有する高価なスイッチング素子を採用する必要がないため、ＦＣコンバータ１０（ひいてはシステム全体）の製造コストの上昇を抑制することができる。また、冷却水の温度が常温（例えばＴ４（℃））である場合には、ＦＣコンバータ１０の過電圧閾値を大きい値（ＶＦＣ３（Ｖ））に設定することにより、高い電圧での制御を実現させることができる。 In the fuel cell system 1 according to the embodiment described above, the overvoltage threshold of the FC converter 10 can be switched according to the temperature of the cooling water that cools the FC converter 10 and the like. Therefore, in a low temperature environment where the temperature of the cooling water is lower than room temperature (for example, less than T2 (° C.)), the switching element is set by setting the overvoltage threshold of the FC converter 10 to a small value (V FC1 (V)). Can be protected. For this reason, since it is not necessary to employ an expensive switching element having a high withstand voltage performance even in a low temperature environment, an increase in manufacturing cost of the FC converter 10 (and thus the entire system) can be suppressed. Further, when the temperature of the cooling water is normal temperature (for example, T4 (° C.)), the overvoltage threshold of the FC converter 10 is set to a large value (V FC3 (V)), thereby realizing a high voltage control. Can be made.
　また、以上説明した実施形態に係る燃料電池システム１においては、冷却水の温度に応じてバッテリコンバータ６の昇圧目標電圧制限値を切り替えることができ、この昇圧目標電圧制限値の切替と同期させてＦＣコンバータ１０の過電圧閾値を切り替えることができる。 In the fuel cell system 1 according to the embodiment described above, the boost target voltage limit value of the battery converter 6 can be switched according to the temperature of the cooling water, and is synchronized with the switching of the boost target voltage limit value. The overvoltage threshold of the FC converter 10 can be switched.
　また、以上説明した実施形態に係る燃料電池車両は、冷却水の温度が常温（例えばＴ４（℃））である場合にＦＣコンバータ１０の過電圧閾値を大きい値（ＶＦＣ３（Ｖ））に設定することにより高い電圧での制御を実現させることができる燃料電池システム１を備えるものであるため、高い走行性能を確保することができる。 Further, the fuel cell vehicle according to the embodiment described above sets the overvoltage threshold of the FC converter 10 to a large value (V FC3 (V)) when the temperature of the cooling water is normal temperature (for example, T4 (° C.)). Thus, since the fuel cell system 1 that can realize control at a high voltage is provided, high running performance can be ensured.
　なお、以上説明した実施形態においては、本発明に係る燃料電池システムを燃料電池車両に搭載した例を示したが、燃料電池車両以外の各種移動体（ロボット、船舶、航空機等）に本発明に係る燃料電池システムを搭載することもできる。また、本発明に係る燃料電池システムを、建物（住宅、ビル等）用の発電設備として用いられる定置用発電システムに適用してもよい。さらには、携帯型の燃料電池システムにも適用可能である。 In the above-described embodiment, an example in which the fuel cell system according to the present invention is mounted on a fuel cell vehicle has been shown. Such a fuel cell system can also be mounted. Further, the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for a building (house, building, etc.). Furthermore, the present invention can be applied to a portable fuel cell system.
　１…燃料電池システム、２…燃料電池、３…バッテリ、５…トラクションモータ（負荷装置）、６…バッテリコンバータ、７…コントローラ（閾値切替手段、制限値切替手段）、１０…ＦＣコンバータ（燃料電池コンバータ）。 DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 3 ... Battery, 5 ... Traction motor (load apparatus), 6 ... Battery converter, 7 ... Controller (threshold value switching means, limit value switching means), 10 ... FC converter (fuel cell) converter).

Claims (4)

  1. 　燃料電池と負荷装置との間に設けられた燃料電池コンバータを備える燃料電池システムであって、
    　前記燃料電池コンバータを冷却する冷却水の温度に応じて前記燃料電池コンバータの過電圧閾値を切り替える閾値切替手段を備える、
    燃料電池システム。     A fuel cell system comprising a fuel cell converter provided between a fuel cell and a load device,
    A threshold value switching means for switching an overvoltage threshold value of the fuel cell converter according to a temperature of cooling water for cooling the fuel cell converter;
    Fuel cell system.
  2. 　前記閾値切替手段は、前記冷却水の温度が高くなるに従って前記過電圧閾値を大きくするものである、
    請求項１に記載の燃料電池システム。     The threshold switching means increases the overvoltage threshold as the temperature of the cooling water increases.
    The fuel cell system according to claim 1.
  3. 　バッテリと、
    　前記バッテリと前記負荷装置との間に設けられたバッテリコンバータと、
    　前記冷却水の温度に応じて前記バッテリコンバータの昇圧目標電圧制限値を切り替える制限値切替手段と、を備え、
    　前記閾値切替手段は、前記バッテリコンバータの昇圧目標電圧制限値の切替と同期させて前記燃料電池コンバータの過電圧閾値を切り替えるものである、
    請求項１又は２に記載の燃料電池システム。     Battery,
    A battery converter provided between the battery and the load device;
    Limit value switching means for switching the boost target voltage limit value of the battery converter according to the temperature of the cooling water,
    The threshold value switching means switches the overvoltage threshold value of the fuel cell converter in synchronization with the switching of the boost target voltage limit value of the battery converter.
    The fuel cell system according to claim 1 or 2.
  4. 　請求項１から３の何れか一項に記載の燃料電池システムを備える、
    燃料電池車両。
          The fuel cell system according to any one of claims 1 to 3 is provided.
    Fuel cell vehicle.
PCT/JP2011/069485 2011-08-29 2011-08-29 Fuel cell system and fuel cell vehicle WO2013030933A1 (en)

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JP2008148407A (en) * 2006-12-07 2008-06-26 Yokogawa Electric Corp Overcurrent detection circuit
JP2009081959A (en) * 2007-09-26 2009-04-16 Toyota Motor Corp Controller of step-up/step-down converter
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WO2011021263A1 (en) * 2009-08-17 2011-02-24 トヨタ自動車株式会社 Fuel cell system

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Publication number Priority date Publication date Assignee Title
JPH05151983A (en) * 1991-11-29 1993-06-18 Sanyo Electric Co Ltd Hybrid fuel cell system
JP2008017625A (en) * 2006-07-06 2008-01-24 Renesas Technology Corp Semiconductor device and switching power supply device
WO2008007723A1 (en) * 2006-07-10 2008-01-17 Toyota Jidosha Kabushiki Kaisha Load drive device and vehicle using the same
JP2008148407A (en) * 2006-12-07 2008-06-26 Yokogawa Electric Corp Overcurrent detection circuit
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