Power management device and method for fuel cells

Abstract

To provide an apparatus and a method for managing the power of a fuel cell to mitigate unnecessary power movement between a fuel cell system and a high-voltage battery, which occurs in a starting sequence of a fuel cell vehicle.SOLUTION: An apparatus for managing the power of a fuel cell may include: a power conversion unit that converts a high voltage into a low voltage and supplies it to a low-voltage battery; a cooling unit that flows cooling water to cool the power conversion unit; and a controller that controls driving of the power conversion unit and the cooling unit based on the remaining state of charge of the low voltage battery.SELECTED DRAWING: Figure 3

Description

Technical Field

[0006] ,

[0001] The present invention relates to a power management device and method for a fuel cell.

Background Art

[0002] Generally, a BHDC package includes a bi-directional high voltage DC-DC converter (BHDC) and a low voltage DC-DC converter (LDC).

[0003] BHDC serves to boost the voltage of a high voltage battery and transmit it to a high voltage junction box, and to step down the electrical energy regenerated from the vehicle motor when recharging the high voltage battery. LDC steps down the high voltage output from the fuel cell stack or BHDC to 12V to charge the low voltage battery. The low voltage battery supplies power to low voltage drive devices in the vehicle, including the operating devices of the fuel cell system. Therefore, before the driver starts the vehicle, the charge level of the low voltage battery must be ensured to be above a certain amount.

[0004] [[ID=二十]]The high voltage formed in the high voltage battery is used to drive electrical components for turning on the fuel cell and to charge the low voltage battery via LDC.

[0005] Therefore, when the charge level of the low voltage battery is insufficient, power rapidly moves from the high voltage battery to the low voltage battery simultaneously with the turning on of the high voltage system. At this time, since the power transfer occurs preferentially regardless of whether the fuel cell is on or not, there is a problem that heat generation occurs in BHDC even in a situation where the required power of e-BOP (Electrical Balance of Plant) is not expected in the stand-by step.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One object of the present invention is to provide a fuel cell power management device and method that can improve unwanted power transfer between the fuel cell system and the high-voltage battery that occurs during the starting sequence of a fuel cell vehicle.

[0007] The technical problems of the present invention are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] A power management device for a fuel cell according to one embodiment of the present invention may include a power conversion unit that converts high voltage to low voltage and supplies it to a low-voltage battery, a cooling unit that cools the power conversion unit by circulating cooling water, and a control unit that controls the operation of the power conversion unit and the cooling unit based on the remaining charge amount of the low-voltage battery.

[0009] In one embodiment, the power conversion unit may include a bidirectional high-voltage DC converter that steps down regenerative power to charge a high-voltage battery or steps up the power of a high-voltage battery to supply to an electrical load, and a low-voltage DC converter that converts the output power of the bidirectional high-voltage DC converter to a low voltage to charge the low-voltage battery.

[0010] In one embodiment, the control unit can control the vehicle's low-voltage electrical components to be driven if the amount of hydrogen tank filled at the time of vehicle ignition is greater than a predetermined remaining amount.

[0011] In one embodiment, after driving the bidirectional high-voltage DC converter, if the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage and the remaining charge of the high-voltage battery is greater than a predetermined range, the control unit can drive the low-voltage DC converter to charge the low-voltage battery.

[0012] In one embodiment, after driving the bidirectional high-voltage DC converter, if the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is less than a predetermined range, the control unit can drive the low-voltage DC converter to charge the low-voltage battery.

[0013] In one embodiment, the control unit may drive the cooling unit before driving the low-voltage DC converter.

[0014] In one embodiment, the control unit can drive the fuel cell stack if, after driving the bidirectional high-voltage DC converter, the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is greater than a predetermined range.

[0015] In one embodiment, the control unit can drive the low-voltage DC converter after the fuel cell stack has been driven, and control the system so that the charge level of the low-voltage battery is maintained within a predetermined range.

[0016] A power management method for a fuel cell according to another embodiment of the present invention may include the step of controlling the drive of a power conversion unit that converts high voltage to low voltage and supplies it to the low voltage battery based on the remaining charge amount of the low voltage battery, and a cooling unit that cools the power conversion unit by circulating cooling water.

[0017] In one embodiment, the power management method for the fuel cell may include the steps of: using a bidirectional high-voltage DC converter to step down the regenerative power to charge a high-voltage battery or to step up the power of the high-voltage battery to supply it to an electrical load; and using a low-voltage DC converter to convert the output power of the bidirectional high-voltage DC converter to a low voltage to charge the low-voltage battery.

[0018] In one embodiment, the power management method for the fuel cell may include a step of controlling the vehicle's low-voltage electrical components to be driven if the amount of hydrogen tank filled at the time of vehicle ignition is greater than a predetermined remaining amount.

[0019] In one embodiment, the power management method for the fuel cell may include the step of driving the low-voltage DC converter to charge the low-voltage battery if, after driving the bidirectional high-voltage DC converter, the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage and the remaining charge of the high-voltage battery is greater than a predetermined range.

[0020] In one embodiment, the power management method for the fuel cell may include the step of driving the low-voltage DC converter to charge the low-voltage battery if, after driving the bidirectional high-voltage DC converter, the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is less than a predetermined range.

[0021] In one embodiment, the power management method for the fuel cell may include the step of driving the cooling unit before driving the low-voltage DC converter.

[0022] In one embodiment, the power management method for the fuel cell may include the step of driving the fuel cell stack after driving the bidirectional high-voltage DC converter, if the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is greater than a predetermined range.

[0023] In one embodiment, the power management method for the fuel cell may include the step of driving the low-voltage DC converter after the fuel cell stack has been driven and controlling it so that the charge level of the low-voltage battery is maintained within a predetermined range. [Effects of the Invention]

[0024] This technology improves the unnecessary power transfer between the fuel cell system and the high-voltage battery that occurs during the startup sequence of a fuel cell vehicle, thereby improving the stability of the initialization of the fuel cell system by reducing the radiated noise caused by the high current in the electrical wiring harness.

[0025] In addition, various effects that can be directly or indirectly grasped by this document can be provided.

Brief Description of the Drawings

[0026] [Figure 1] It is a diagram showing a drive system equipped with a fuel cell according to an embodiment of the present invention. [Figure 2] It is a diagram for explaining the cooling process of a drive system equipped with a fuel cell according to an embodiment of the present invention. [Figure 3] It is a block diagram showing a power management device for a fuel cell according to an embodiment of the present invention. [Figure 4] It is a diagram for explaining the charging characteristics of a battery that constitutes a power management device for a fuel cell according to an embodiment of the present invention. [Figure 5] It is a diagram for explaining the noise reduction state through a power management device for a fuel cell according to an embodiment of the present invention. [Figure 6] It is a diagram for explaining the noise reduction state through a power management device for a fuel cell according to an embodiment of the present invention. [Figure 7] It is a flowchart for explaining a power management method for a fuel cell according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0027] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include various modifications, equivalents, or alternatives of the embodiments of the present invention.

[0028] The various embodiments and terminology used herein are not intended to limit the technical features described herein to any particular embodiment, but should be understood to include various modifications, equivalents, or substitutes of such embodiments.

[0029] Similar reference numerals may be used for similar or related components in relation to the description of the drawings. The singular noun corresponding to an item may include one or more of the item unless the context clearly indicates otherwise.

[0030] In this document, each phrase such as "A or B," "at least one of A and B," "at least one of A or B," "A, B, or C," "at least one of A, B, and C," and "at least one of A, B, or C" may include any one of the items listed together with the phrase, or any possible combination thereof.

[0031] Terms such as “first,” “second,” or “first,” or “second” may be used merely to distinguish one component from other such components and not to limit it in any other respect (e.g., importance or order). When a component (e.g., the first) is referred to as “connected” or “linked” to another component (e.g., the second), with or without such terms, it means that the first component may be connected to the other component directly (e.g., by wire), wirelessly, or via the third component.

[0032] Figure 1 is a diagram showing a drive system equipped with a fuel cell according to one embodiment of the present invention, Figure 2 is a diagram illustrating the cooling process of a drive system equipped with a fuel cell according to one embodiment of the present invention, Figure 3 is a block diagram showing a power management device for a fuel cell according to one embodiment of the present invention, and Figure 4 is a diagram illustrating the charging characteristics of a battery constituting a power management device for a fuel cell according to one embodiment of the present invention.

[0033] Referring to Figures 1 to 3, a drive system equipped with a fuel cell can be configured to include a fuel cell system 100, a power converter 200, a high-voltage battery 310, a low-voltage battery 320, a high-voltage junction unit 400, a DC converter unit 600, an inverter unit 700, and a motor 800.

[0034] The fuel cell system 100 is a type of power generation system that generates electricity through an electrochemical reaction between hydrogen and oxygen (oxygen in the air) within a fuel cell stack 120, utilizing the chemical energy contained in the fuel. The fuel cell system 100 may include a fuel cell stack 120 comprising a fuel electrode (anode) and an air electrode (cathode) for generating electricity, a hydrogen supply device (not shown) for supplying hydrogen stored in a hydrogen tank 110 to the fuel electrode, and an air supply device (not shown) for supplying air to the air electrode.

[0035] With this configuration, the fuel cell system 100 generates electricity by reacting hydrogen, which is the fuel, with oxygen in the air, and emits heat and water as reaction byproducts.

[0036] The power conversion unit 200 may include a bidirectional high voltage DC / DC converter (BHDC) 210 and a low voltage DC / DC converter (LDC) 220.

[0037] The BHDC210 is responsible for boosting the voltage of the high-voltage battery 310 and sending it to the high-voltage junction 400, and also for stepping down the voltage when regenerating power from the motor 800 to recharge the high-voltage battery 310. The BHDC210 can then supply power to electrical loads such as the DC / DC converter 600, inverter 700, and motor 800 via the high-voltage junction 400.

[0038] The LDC220 is a unidirectional DC / DC converter. The LDC220 can convert the output voltage of the fuel cell stack 120 or the output voltage of the BHDC210 to a low voltage of 12V to charge the low-voltage battery 320 and supply energy to the electrical balance of plant (E-BOP) 60 that constitute the fuel cell vehicle.

[0039] The LDC220 can start a fuel cell vehicle by operating in boost mode, which boosts the low voltage applied from the low-voltage battery 320 and applies high voltage to each component of the high-voltage battery 310 when the fuel cell vehicle is starting. When not starting a fuel cell vehicle, the LDC220 can operate in buck mode, which steps down the high voltage applied from the high-voltage battery 310 to charge the low-voltage battery 320 or to supply voltage to each electrical component 60 in the fuel cell vehicle. The LDC220 can operate in boost mode or buck mode via a buck / boost converter 170.

[0040] The high-voltage battery 310 is a high-capacity lithium-ion battery that enables the fuel cell vehicle to operate solely on the power of the high-voltage battery 310 in Electric Vehicle Mode (EV mode). The voltage supplied from the high-voltage battery 310 is boosted to 250-400V by the BHDC 210 and then supplied to the electrical load via the high-voltage junction 400.

[0041] There are two possible paths for supplying high-voltage power to the electrical load. In the first case, when the fuel cell stack 120 operates after the fuel cell vehicle starts up, the power produced from the fuel cell stack 120 can be boosted to 250-400V by the BHDC 210 and then supplied to the electrical load via the high-voltage junction 400. In the second case, without using the power from the fuel cell stack 120, the power charged in the high-voltage battery 310 can be boosted to 250-400V by the BHDC 210 and then supplied to the electrical load via the high-voltage junction 400.

[0042] The low-voltage battery 320 is a lithium-ion battery and can be charged by the low voltage input from the LDC220.

[0043] The low-voltage battery 320 serves as an energy source for electrical components 60 such as the air conditioning system inside the vehicle cabin, and also acts as a power source for the main control units of the fuel cell system 100, such as the fuel cell control unit (FCU) and the motor control unit (MCU), playing an essential role in the initial drive of the fuel cell vehicle.

[0044] Since the low-voltage battery 320 supplies power to the low-voltage drive unit in the fuel cell vehicle, including the operating unit of the fuel cell system 100, the charge level of the low-voltage battery 320 must be at least a certain amount before starting the fuel cell vehicle.

[0045] The high-voltage junction section 400 can receive power from the fuel cell system 100 and the BHDC 210, and then distribute that high voltage to electrical loads that require it.

[0046] The DC conversion unit 600 can convert the output voltage of the fuel cell system 100 or the output voltage of the BHDC 210 transmitted via the high-voltage junction unit 400 into a low voltage.

[0047] The inverter unit 700 can convert the DC power received via the DC conversion unit 600 into AC power capable of driving the motor 800.

[0048] The motor 800 is mounted on the front or rear wheel of the fuel cell vehicle, and is electrically connected to a motor reducer via the inverter unit 700 to drive the fuel cell vehicle.

[0049] On the other hand, the first thing to be done in the starting sequence of the fuel cell system 100 is the formation of a high voltage. The formed high voltage can be used to drive the electrical components 60 for starting the fuel cell system 100, and can also be used to charge the low-voltage battery 320 via the LDC 220.

[0050] If the low-voltage battery 320 is undercharged, power may rapidly transfer from the high-voltage battery 310 to the low-voltage battery 320 at the same time as the formation of a high voltage. In this case, if power transfer from the high-voltage battery 310 to the low-voltage battery 320 occurs independently of the starting of the fuel cell system 100, heat may be generated in the BHDC 210 during the fuel cell system 100 starting preparation step, even though the electrical components 60 are not driven.

[0051] Therefore, before starting the fuel cell system 100, a cooling device through which cooling water flows must be activated to cool the power electronics (PE) that generate heat.

[0052] On the other hand, referring to Figure 2, the temperature of the cooling water used to cool the heat-generating power electronic components rises, and as the heated cooling water flows along the cooling channel 190, it can raise the temperatures of the BPCU (Blower Power Control Unit) 160, buck / boost converter 170, ACL (Air Cooler) 180, and other components, including the BHDC 210, LDC 220, high-voltage battery 310, and low-voltage battery 320.

[0053] The cooling system may consist of a reservoir 130, a radiator 140, and a cooling pump (CPP; Coolant Power-electric cooling Pump) 150.

[0054] The reservoir 130 can serve as a water tank for storing the cooling water that circulates along the cooling channel 190. The radiator 140 can cool the cooling water, which has risen in temperature as it flows along the cooling channel 190, by heat exchange with the outside air. The cooling pump 150 can provide the driving force to circulate the cooling water stored in the reservoir 130 through the cooling channel 190 to the fuel cell system 100 and power electronic components, etc.

[0055] In this configuration, the cooling system can cool the fuel cell system 100 and power electronic components to prevent overheating by circulating the cooling water cooled by the radiator 140 along the cooling channel 190 through the operation of the cooling pump 150. The cooling system may include a thermal management system (TMS).

[0056] If cooling water, which has been heated by cooling the power electronic components before the fuel cell system 100 is started, flows into the fuel cell system 100, the fuel cell system 100 may not start stably when it is started.

[0057] The control unit 500 can, when it is not necessary to charge the low-voltage battery 320 via the LDC220, cut off the current flow for charging the low-voltage battery 320 in the LDC220 before starting the fuel cell system 100, thereby preventing overheating of power electronic components.

[0058] Referring to Figure 4, since the low-voltage battery 320 is a lithium-ion polymer battery, its battery voltage characteristics are stable (steady) in relation to the state of charge (SOC). That is, even if the charge level is high and insufficient, the voltage value is maintained, and even when it approaches the over-discharge limit, there may still be sufficient power to start the fuel cell system 100.

[0059] The control unit 500 can control the low-voltage battery 320 so that it is not charged before the fuel cell system 100 is started, provided that the low-voltage battery 320 has a charge level sufficient to power the low-voltage electrical components 60. The control unit 500 may include a Hydrogen Management System (HMU), a Vehicle Control Unit (VCU), a Fuel Cell Control Unit (FCU), or a Micro Control Unit (MCU).

[0060] When ignition, which is the preparation for starting, is performed via the starting input unit 50 of the fuel cell vehicle, the control unit 500 can determine that the low-voltage battery 320 is not discharged. Therefore, the control unit 500 can control the system so that the low-voltage battery 320 is not charged.

[0061] Next, the control unit 500 determines that the fuel cell vehicle can be operated using the electricity from the fuel cell system 100 and can confirm the amount of hydrogen filled in the hydrogen tank 110.

[0062] The control unit 500 can determine that the fuel cell system 100 can be driven when the hydrogen level (SOF) of the hydrogen tank 110 is 20% or more. Since the fuel cell system 100 can be driven based on the hydrogen level of the hydrogen tank 110, the control unit 500 can maintain a state in which the low-voltage battery 320 is not charged.

[0063] The control unit 500 can confirm that power from the low-voltage battery 320 is being applied to the electrical components 60 of the fuel cell vehicle when ignition is performed via the start input unit 50.

[0064] Next, the control unit 500 can drive the high-voltage battery 310 and control it so that the high voltage output from the high-voltage battery 310 is applied to the BHDC 210.

[0065] On the other hand, the control unit 500 can operate the high-voltage battery 310 and control it so that the high voltage output from the high-voltage battery 310 is applied to the BHDC 210 if it determines that the fuel cell vehicle can be operated with the power stored in the high-voltage battery 310 or if the amount of hydrogen filled in the hydrogen tank 110 (SOF) is less than 20%.

[0066] When the high voltage output from the high-voltage battery 310 is applied to the BHDC210, the power of the high-voltage battery 310 can be boosted to be equivalent to the power output from the fuel cell system 100. At this time, the fuel cell system 100 is not running, while the high-voltage battery 310 and the low-voltage battery 320 can be running.

[0067] In this state, the control unit 500 can maintain a state in which the low-voltage battery 320 is not charged.

[0068] Next, the control unit 500 can check the input terminal voltage of the LDC220. The input terminal voltage of the LDC220 and the output voltage of the BHDC210 must be the same. Therefore, the control unit 500 can determine that the LDC220 is functioning normally only if the input terminal voltage exceeds 300V, but if the input terminal voltage of the LDC220 is less than 300V, it can determine that the high-voltage battery 310 is either undercharged or in a faulty state.

[0069] When the input terminal voltage of the LDC220 exceeds 300V, the control unit 500 determines that the state of the high-voltage battery 310 is normal and can check the charge level of the high-voltage battery 310.

[0070] The control unit 500 can control the LDC 220 to charge the low-voltage battery 320 if the charge level of the high-voltage battery 310 is greater than 85%, because the fuel cell vehicle can be driven using the power of the high-voltage battery 310 without driving the fuel cell system 100. In this case, the charging speed of the low-voltage battery 320 can be 10A per second.

[0071] The control unit 500 can check the charge level of the low-voltage battery 320 if the charge level of the high-voltage battery 310 is less than 85%.

[0072] The control unit 500 can drive the low-voltage electrical components 60 without charging the low-voltage battery 320 if the charge level of the low-voltage battery 320 is greater than 10%, thus maintaining a state in which the low-voltage battery 320 is not charged. In this case, since the low-voltage battery 320 is not charged and does not generate heat, it is not necessary to drive the cooling device.

[0073] The control unit 500 can control the LDC220 to charge the low-voltage battery 320 when its charge level is less than 10%. In this case, the charging speed of the low-voltage battery 320 can be set to 10A per second. Since heat is generated when the low-voltage battery 320 is charged by driving the LDC220, the control unit 500 can drive the cooling device to maximum before driving the LDC220.

[0074] Next, the control unit 500 can drive the fuel cell system 100. Once the fuel cell system 100 is driven, sufficient power is generated from it, so the control unit 500 can drive the LDC 220 to charge the low-voltage battery 320. In this case, the charging speed of the low-voltage battery 320 can be 5A per second.

[0075] The control unit 500 can drive the LDC220 while the fuel cell vehicle is in operation and control it so that the low-voltage battery 320 is charged while maintaining a charge level of 80% to 85%.

[0076] Figures 5 and 6 illustrate the noise reduction state via a power management device for a fuel cell according to one embodiment of the present invention.

[0077] Referring to Figure 5, it can be seen that during the startup process of the fuel cell system 100, when power is transferred from the high-voltage battery 310 to the low-voltage battery 320, heat is generated in the BHDC 210 even though the low-voltage electrical components 60 are not driven, and a lot of noise is generated when the cooling device is driven.

[0078] However, referring to Figure 6, it can be seen that if power transfer from the high-voltage battery 310 to the low-voltage battery 320 is prevented during the startup process of the fuel cell system 100, no heat is generated in the BHDC210, the cooling device is not driven, and thus the noise is relatively reduced.

[0079] Furthermore, the control unit 500 can control at least one other component (e.g., hardware or software component) of the fuel cell's power management device and perform various data processing or calculations.

[0080] According to one embodiment, as part of data processing or calculation, the control unit 500 can store instructions or data received from other components (e.g., sensors) in a volatile memory, process the instructions or data stored in the volatile memory, and store the resulting data in a non-volatile memory.

[0081] According to one embodiment, the control unit 500 may include a main processor (e.g., a central processing unit or application processor) or an auxiliary processor (e.g., a graphics processing unit, an image signal processor, a sensor hub processor, or a communication processor) that can operate independently or together with it. For example, if the control unit 500 includes a main processor and an auxiliary processor, the auxiliary processor may use less power than the main processor or be configured to specialize in a specified function. The auxiliary processor may be implemented separately from or as part of the main processor.

[0082] Although not shown in the illustrations, according to the embodiment, the power management device for the fuel cell may further include a storage unit.

[0083] The storage unit can store instruction words, control instruction code, control data, or user data for controlling the fuel cell's power management device. For example, the storage unit may include at least one of the following: an application program, an operating system, middleware, or a device driver.

[0084] The storage unit may include one or more volatile memory or non-volatile memory.

[0085] Volatile memory can include DRAM (dynamic random access memory), SRAM (static RAM), SDRAM (synchronous DRAM), PRAM (phase-change RAM), MRAM (magnetic RAM), RRAM (resistive RAM), and FeRAM (ferroelectric RAM), among others.

[0086] Non-volatile memory can include ROM (read-only memory), PROM (programmable ROM), EPROM (electrically programmable ROM), EEPROM (electrically erasable programmable ROM), and flash memory.

[0087] The storage compartment may further include non-volatile media such as hard disk drives (HDDs), solid state disks (SSDs), embedded multimedia cards (eMMCs), and universal flash storage (UFSs).

[0088] Hereinafter, with reference to Figure 8, a power management method for a fuel cell according to another embodiment of the present invention will be specifically described.

[0089] Figure 7 is a flowchart illustrating a power management method for a fuel cell according to one embodiment of the present invention.

[0090] In the following, we assume that the power management device for the fuel cell in Figure 3 performs the process shown in Figure 7.

[0091] First, when ignition, which is preparation for starting, is performed via the starting input unit 50 of the fuel cell vehicle (S101), the control unit 500 determines that the fuel cell vehicle can be operated with the power from the fuel cell system 100 (S102), and can confirm the amount of hydrogen filled in the hydrogen tank 110 (S103).

[0092] The control unit 500 can confirm that power from the low-voltage battery 320 is applied to the electrical components 60 of the fuel cell vehicle when ignition is performed via the start input unit 50 (S104).

[0093] Next, the control unit 500 can drive the high-voltage battery 310 and control it so that the high voltage output from the high-voltage battery 310 is applied to the BHDC 210 (S105).

[0094] On the other hand, the control unit 500 can operate the high-voltage battery 310 and control it so that the high voltage output from the high-voltage battery 310 is applied to the BHDC 210 if it determines that the fuel cell vehicle can be operated with the power stored in the high-voltage battery 310 or if the amount of hydrogen filled in the hydrogen tank 110 (SOF) is less than 20%.

[0095] Next, the control unit 500 can check the input terminal voltage of the LDC220 (S106).

[0096] The control unit 500 can determine that the high-voltage battery 310 is either undercharged or in a faulty state if the input terminal voltage of the LDC220 is less than 300V (S107).

[0097] When the input terminal voltage of the LDC220 exceeds 300V, the control unit 500 determines that the state of the high-voltage battery 310 is normal and can check the charge level of the high-voltage battery 310 (S108).

[0098] The control unit 500 can control the LDC 220 to charge the low-voltage battery 320 if the charge level of the high-voltage battery 310 is greater than 85%, because the fuel cell vehicle can be driven by the power of the high-voltage battery 310 without driving the fuel cell system 100 (S109).

[0099] The control unit 500 can check the charge level of the low-voltage battery 320 if the charge level of the high-voltage battery 310 is less than 85% (S110).

[0100] The control unit 500 can drive the low-voltage electrical components 60 without charging the low-voltage battery 320 if the charge level of the low-voltage battery 320 is greater than 10%, thus maintaining a state in which the low-voltage battery 320 is not charged. In this case, since the low-voltage battery 320 is not charged and does not generate heat, it is not necessary to drive the cooling device.

[0101] If the charge level of the low-voltage battery 320 is less than 10%, the control unit 500 can first drive the cooling device to its maximum capacity (S111) before driving the LDC220, and then control the LDC220 to drive and charge the low-voltage battery 320 (S112).

[0102] Next, the control unit 500 can drive the fuel cell system 100 (S113).

[0103] Next, the control unit 500 can drive the LDC220 to charge the low-voltage battery 320 (S114).

[0104] Next, the control unit 500 can drive the LDC220 while the fuel cell vehicle is in operation and control it so that the low-voltage battery 320 is charged while maintaining a charge level of 80% to 85% (S115).

[0105] Various embodiments of this document may be implemented as software (e.g., a program) containing one or more instruction words stored in a machine-readable storage medium (e.g., internal memory or external memory). For example, the machine may invoke and execute at least one instruction from the one or more instruction words stored in the storage medium. This allows the machine to operate to perform at least one function in response to the invoked at least one instruction word. The one or more instruction words may include code generated by a compiler or code executable by an interpreter.

[0106] The device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, "non-transitory" simply means that the storage medium is a tangible device and does not contain signals (e.g., electromagnetic waves), and this term does not distinguish between cases where data is stored on the storage medium semi-permanently and cases where it is stored temporarily.

[0107] According to one embodiment, the methods of the various embodiments disclosed herein may be provided in a computer program product. The computer program product may be traded as a commodity between a seller and a buyer. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)) or online (e.g., download or upload) via an application store or directly between two user devices. In the case of online distribution, at least a portion of the computer program product may be at least temporarily stored or temporarily generated on a device-readable storage medium such as the memory of a manufacturer's server, an application store server, or an intermediary server.

[0108] According to various embodiments, each of the components described above (e.g., a module or a program) may include one or more individuals, and some of the individuals may be separated and arranged in other components.

[0109] In various embodiments, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added.

[0110] Multiple components (e.g., modules or programs) may be integrated into a single component, either broadly or additionally. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar way as those previously performed by the components of the multiple components.

[0111] According to various embodiments, the operations performed by the module, program, or other components may be performed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be performed in a different order, omitted, or one or more other operations may be added.

[0112] As described above, the present invention improves the unnecessary power transfer between the fuel cell system and the high-voltage battery that occurs during the starting sequence of a fuel cell vehicle, thereby improving the stability of the initial setup of the fuel cell system by reducing radiated noise due to high current in the electrical lines.

[0113] The above description is merely illustrative of the technical concept of the present invention, and a person with ordinary skill in the art to which the present invention belongs can make various modifications and variations without departing from the essential characteristics of the present invention.

[0114] Therefore, the embodiments disclosed herein are for illustrative purposes only, not to limit the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by such embodiments. The scope of protection of the present invention must be interpreted in accordance with the claims described below, and all technical concepts within an equivalent scope should be interpreted as being included within the scope of the rights of the present invention.

Claims

1. A power conversion unit that converts high voltage to low voltage and supplies it to a low-voltage battery, A cooling unit that cools the power conversion unit by circulating cooling water, A control unit that controls the operation of the power conversion unit and the cooling unit based on the remaining charge amount of the low-voltage battery. Includes, The power conversion unit is A bidirectional high-voltage DC converter that either steps down regenerative power to charge a high-voltage battery or steps up the power from a high-voltage battery to supply to an electrical load, The system includes a low-voltage DC converter that converts the output power of the bidirectional high-voltage DC converter to a low voltage to charge the low-voltage battery, A power management device for a fuel cell, characterized in that, after driving the bidirectional high-voltage DC converter, if the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage and the remaining charge amount of the high-voltage battery is greater than a predetermined range, the control unit drives the low-voltage DC converter to charge the low-voltage battery.

2. The power management device for a fuel cell according to claim 1, characterized in that the control unit controls the vehicle's low-voltage electrical components to be driven when the amount of hydrogen tank filled at the time of vehicle ignition.

3. The power management device for a fuel cell according to claim 1, characterized in that, after driving the bidirectional high-voltage DC converter, if the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is less than a predetermined range, the control unit drives the low-voltage DC converter to charge the low-voltage battery.

4. The power management device for a fuel cell according to claim 1 or 3, characterized in that the control unit drives the cooling unit before driving the low-voltage DC converter.

5. The power management device for a fuel cell according to claim 1, characterized in that, after driving the bidirectional high-voltage DC converter, the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is greater than a predetermined range.

6. The power management device for a fuel cell according to claim 5, characterized in that the control unit drives the low-voltage DC converter after the fuel cell stack has been driven, and controls the amount of charge of the low-voltage battery to be maintained within a predetermined range.

7. Based on the remaining charge of the low-voltage battery, A power conversion unit that converts high voltage to low voltage and supplies it to the low-voltage battery, and a cooling unit that controls the drive of the cooling unit that cools the power conversion unit by circulating cooling water. A method for managing the power of a fuel cell, including, The power management method for the fuel cell is as follows: In a bidirectional high-voltage DC converter, the steps include step-by-stepping the regenerative power to charge a high-voltage battery or step-up the power of the high-voltage battery to supply it to an electrical load, In a low-voltage DC converter, the steps include: converting the output power of the bidirectional high-voltage DC converter to a low voltage to charge the low-voltage battery; The power management method for the fuel cell is characterized by including the step of driving the low voltage DC converter to charge the low voltage battery if, after driving the bidirectional high voltage DC converter, the input terminal voltage of the low voltage DC converter is higher than a predetermined voltage and the remaining charge amount of the high voltage battery is greater than a predetermined range.

8. The power management method for the fuel cell according to claim 7, characterized in that the method includes a step of controlling the vehicle's low-voltage electrical components to be driven when the amount of hydrogen tank filled at the time of vehicle ignition.

9. The power management method for the fuel cell according to claim 7, characterized in that, after driving the bidirectional high-voltage DC converter, if the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is less than a predetermined range, the power management method for the fuel cell according to claim 7, further comprising the step of driving the low-voltage DC converter to charge the low-voltage battery.

10. The power management method for the fuel cell according to claim 7 or 9, characterized in that the method includes a step of driving the cooling unit before driving the low-voltage DC converter.

11. The power management method for the fuel cell according to claim 7, characterized in that, after driving the bidirectional high-voltage DC converter, the input terminal voltage of the low-voltage DC converter is higher than a predetermined voltage, the remaining charge of the high-voltage battery is less than a predetermined range, and the remaining charge of the low-voltage battery is greater than a predetermined range, the power management method for the fuel cell according to claim 7.

12. The power management method for the fuel cell according to claim 11, characterized in that the power management method for the fuel cell includes the step of driving the low-voltage DC converter after driving the fuel cell stack and controlling it so that the charge amount of the low-voltage battery is maintained within a predetermined range.

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