A fuel cell system without dc-dc converter

Abstract

The application discloses a fuel cell system without direct current converter, relates to the technical field of hydrogen fuel cell system high-voltage platform architecture, and comprises a fuel cell module and a vehicle power module. The fuel cell module is used for generating electric energy. The vehicle power module comprises a first high-voltage power distribution unit, a bidirectional DCDC unit and an energy storage unit. The first high-voltage power distribution unit is used for obtaining the electric energy. The bidirectional DCDC unit is used for realizing energy conversion between the first high-voltage power distribution unit and the energy storage unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen fuel cell system high-voltage platform architecture, and particularly relates to a fuel cell system without a direct-current converter. BACKGROUND

[0002] At present, a DCDC power unit is contained in a hydrogen fuel cell system high-voltage architecture, and the DCDC is responsible for converting unstable direct-current voltage output by a stack into stable direct-current voltage for power supply of a vehicle power battery and high-voltage components.

[0003] However, in this high-voltage architecture, the DCDC is a core component of the fuel cell system, and the cost of the DCDC is also among the top of the fuel cell system cost. In the case that the reliability, dynamic response, and service life of the stack and other technical indexes are increasingly mature, a new type of high-voltage architecture needs to be designed to reduce the dependence of the fuel cell system on the DCDC and reduce the cost of the fuel cell system. At present, there is no proper method to solve the above problems. Therefore, it is necessary to propose a fuel cell system without a direct-current converter to at least solve part of the above problems. SUMMARY

[0004] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiments section. The summary section of the present application does not mean to attempt to limit the key features and essential technical features of the claimed technical solution, nor to attempt to determine the protection scope of the claimed technical solution.

[0005] In a first aspect, an embodiment of the present application provides a fuel cell system without a direct-current converter, the system comprising:

[0006] a fuel cell module configured to generate electric energy;

[0007] a vehicle power module comprising a first high-voltage power distribution unit, a bidirectional DCDC unit, and an energy storage unit, the first high-voltage power distribution unit configured to obtain the electric energy, and the bidirectional DCDC unit configured to realize energy conversion between the first high-voltage power distribution unit and the energy storage unit.

[0008] In an embodiment of the present application, the fuel cell module comprises a stack and a second high-voltage power distribution unit.

[0009] The stack is configured to obtain chemical energy from fuel and convert the chemical energy into the electric energy according to an electrochemical reaction;

[0010] The second high-voltage power distribution unit is configured to distribute the electric energy.

[0011] In one embodiment of the present application, the second high-voltage power distribution unit comprises a hydrogen residual discharge switch, a voltage sensor, a current sensor, a protector, and an integrated air compressor controller.

[0012] The voltage sensor is connected in parallel with the hydrogen residual discharge switch, the voltage sensor is configured to detect a bus voltage, the hydrogen residual discharge switch is connected in series with the current sensor, the current sensor is configured to detect a stack output current and a fuel cell system net output current, the protector is connected in parallel with the hydrogen residual discharge switch, and the protector is connected in series with the integrated air compressor controller.

[0013] In one embodiment of the present application, the fuel cell module further comprises a fuel cell control unit.

[0014] The fuel cell control unit is configured to calculate a stack power based on the bus voltage and the stack output current, the fuel cell unit is further configured to calculate a fuel cell system power based on the bus voltage and the fuel cell system net output current, and the fuel cell unit is further configured to transmit the stack power and the fuel cell system power to a vehicle CAN network.

[0015] In one embodiment of the present application, the fuel cell control unit is further configured to detect whether the bus voltage is higher than a preset safety threshold in the case that the fuel cell system without direct current converter is shut down, and the fuel cell control unit is further configured to close the hydrogen residual discharge switch until the bus voltage is lower than the preset safety threshold in the case that the bus voltage is lower than the preset safety threshold.

[0016] In one embodiment of the present application, the bidirectional DCDC unit comprises a power device and a high-frequency inductor.

[0017] The power device is connected in series with the high-frequency inductor, the power device is configured to boost or buck the bus voltage, and the high-frequency inductor is configured to convert the obtained voltage to obtain an output power.

[0018] In one embodiment of the present application, the power device comprises a first power device and a second power device.

[0019] The first power device and the second power device are connected in series, the power device is configured to buck the bus voltage in the case that the bus voltage is greater than a target voltage, the first power device is turned on and the second power device is turned off.

[0020] In one embodiment of the present application, the power device is configured to boost the bus voltage in the case that the bus voltage is less than a target voltage, the first power device is turned off and the second power device is turned on.

[0021] In one embodiment of the present application, the bidirectional DCDC unit further comprises a pre-charge branch relay, a main positive relay, a pre-charge relay and a pre-charge resistor.

[0022] The pre-charge branch relay is connected in parallel with the main positive relay, the pre-charge branch relay is connected in series with the pre-charge resistor, the pre-charge resistor is connected in series with the pre-charge relay, the pre-charge branch relay and the pre-charge resistor are used to limit the size of the charging current flowing into the capacitor, the main positive relay is connected in series with the pre-charge relay, the main positive relay is used to provide current for the fuel cell system without DC conversion when the capacitor charging is completed, and the pre-charge relay is used to provide a path for the pre-charge current of the capacitor.

[0023] In one embodiment of the present application, when the bus voltage is less than the preset voltage, the pre-charge branch relay and the pre-charge relay are both closed to form a pre-charge loop.

[0024] When the bus voltage is greater than or equal to the preset voltage, the pre-charge branch relay is disconnected and the main positive relay is closed to provide current for the fuel cell system without DC conversion.

[0025] In summary, the fuel cell system without DC conversion according to the embodiments of the present application comprises a fuel cell module for generating electric energy, a vehicle power module comprising a first high-voltage power distribution unit, a bidirectional DCDC unit and an energy storage unit, the first high-voltage power distribution unit is used to obtain the electric energy, and the bidirectional DCDC unit is used to realize energy conversion between the first high-voltage power distribution unit and the energy storage unit. By directly connecting the stack output to the second high-voltage power distribution unit and adding a 50KW bidirectional DCDC unit between the first high-voltage power distribution unit and the energy storage unit, the bidirectional DCDC unit is mainly used for energy conversion between the energy storage unit and the first high-voltage power distribution unit. When the bus voltage is too high, the voltage can be reduced to charge the energy storage unit, and when the bus voltage is too low, the voltage can be reversely boosted to provide voltage for the bus, thereby reducing the dependence of the fuel cell system on the DCDC and the dependence of the vehicle on the power battery.

[0026] The fuel cell system without DC conversion according to the present application has other advantages, objects and features which will be embodied in part by the following description and will be understood by those skilled in the art through research and practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in

[0028] Figure 1 A structure schematic diagram of a fuel cell system without DC converter provided by an embodiment of the present application;

[0029] Figure 2 A structure schematic diagram of a first high-voltage power distribution unit in a fuel cell system without DC converter provided by an embodiment of the present application;

[0030] Figure 3 A structure schematic diagram of a second high-voltage power distribution unit in a fuel cell system without DC converter provided by an embodiment of the present application;

[0031] Figure 4 A structure schematic diagram of a bidirectional DC / DC unit in a fuel cell system without DC converter provided by an embodiment of the present application;

[0032] Wherein, Figures 1-4 The correspondence between the reference signs and the component names in the drawings is as follows:

[0033] 101 fuel cell module, 1011 stack, 1012 second high-voltage power distribution unit, 10121 excess hydrogen discharge switch, 10122 voltage sensor, 10123 current sensor, 10124 protector, 10125 integrated air compressor controller, 1013 fuel cell control unit, 201 vehicle power module, 2011 first high-voltage power distribution unit, 2012 bidirectional DC / DC unit, 20121 power device, 201211 first power device, 201212 second power device, 20122 high-frequency inductor, 20123 pre-charge branch relay, 20124 main positive relay, 20125 pre-charge relay, 20126 pre-charge resistor, 2013 energy storage unit. DETAILED DESCRIPTION

[0034] In order to better understand the technical solutions provided by the embodiments of the present application, the technical solutions of the embodiments of the present application will be described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solutions of the embodiments of the present application, and are not limitations of the technical solutions of the present application. In the case of no conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0035] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. The terms "two or more" and "a plurality of" include two or more.

[0036] Referring to Figure 1 A fuel cell system structure diagram without direct current converter is provided for the embodiments of the present application, and specifically can include:

[0037] A fuel cell module 101, which is configured to generate electric energy;

[0038] A vehicle power module 201, which includes a first high-voltage power distribution unit 2011, a bidirectional DCDC unit 2012, and an energy storage unit 2013. The first high-voltage power distribution unit 2011 is configured to obtain the electric energy, and the bidirectional DCDC unit 2012 is configured to realize energy conversion between the first high-voltage power distribution unit 2011 and the energy storage unit 2013.

[0039] For example, Figure 2As shown, it is a structural schematic diagram of a first high-voltage power distribution unit in a fuel cell system structure without a direct-current converter provided by an embodiment of the present application. The fuel cell module 101 is used to generate electric energy. It is a device that directly converts the chemical energy of fuel (such as hydrogen) and oxidant (such as oxygen) into electric energy. It generates electric current through an electrochemical reaction to provide a power source for the entire system. The bidirectional DCDC unit 2012 can realize energy conversion between the first high-voltage power distribution unit 2011 and the energy storage unit 2013. When the output power of the fuel cell module 101 is greater than the demand of the whole vehicle, the bidirectional DCDC unit 2012 can store the excess energy in the energy storage unit 2013, for example, convert high-voltage direct current into voltage and current suitable for charging the energy storage unit 2013. When the output power of the fuel cell module 101 is insufficient, the bidirectional DCDC unit 2012 can extract energy from the energy storage unit 2013 to supplement the whole vehicle power system to meet the power demand of the whole vehicle. The energy storage unit 2013 is usually a power battery or a super capacitor, which can provide additional energy when the output power of the fuel cell is insufficient, and improve the power performance and cruising range of the whole vehicle. In the case of brake energy recovery, the energy storage unit 2013 can also store the recovered energy to improve energy utilization efficiency.

[0040] In summary, the fuel cell system without a direct-current converter provided by the embodiment of the present application directly connects the output of the stack 1011 to the second high-voltage power distribution unit 1012, and installs a 50KW bidirectional DCDC unit 2012 between the first high-voltage power distribution unit 2011 and the energy storage unit 2013. The bidirectional DCDC unit 2012 is mainly used for energy conversion between the energy storage unit 2013 and the first high-voltage power distribution unit 2011. When the bus voltage is too high, it can be stepped down to charge the energy storage unit 2013. When the bus voltage is too low, it can be reversely boosted to provide voltage for the bus, so as to reduce the dependence of the fuel cell system on the DCDC and the dependence of the whole vehicle on the power battery.

[0041] In some examples, the fuel cell module 101 includes: a stack 1011 and a second high-voltage power distribution unit 1012;

[0042] The stack 1011 is used to obtain chemical energy from fuel, and convert the chemical energy into electric energy according to an electrochemical reaction;

[0043] The second high-voltage power distribution unit 1012 is used to distribute the electric energy.

[0044] The stack 1011 is an example of a core component of the fuel cell module 101. It extracts chemical energy from fuel, typically hydrogen. Through electrochemical reactions, the chemical energy is directly converted into electrical energy. The second high-voltage distribution unit 1012 is used to distribute the electrical energy generated by the stack 1011. The electrical energy is distributed to different loads or systems, such as the main drive motor, DCL, air conditioner, PTC (Positive Temperature Coefficient), and other high-voltage components, to meet the power requirements of the fuel cell module 101 itself and the systems connected to it.

[0045] In some examples, the second high-voltage distribution unit 1012 includes a hydrogen discharge switch 10121, a voltage sensor 10122, a current sensor 10123, a protector 10124, and an integrated air compressor controller 10125.

[0046] The voltage sensor 10122 is connected in parallel with the hydrogen discharge switch 10121, and the voltage sensor 10122 is used to detect the bus voltage. The hydrogen discharge switch 10121 is connected in series with the current sensor 10123, and the current sensor 10123 is used to detect the stack output current and the net output current of the fuel system. The protector 10124 is connected in parallel with the hydrogen discharge switch 10121, and the protector 10124 is connected in series with the integrated air compressor controller 10125.

[0047] As shown in the example of Figure 3 The voltage sensor 10122 is used to detect the bus voltage, i.e. the voltage of the main power supply circuit in the circuit. The hydrogen discharge switch 10121 is used to control the discharge process of excess hydrogen in the fuel cell. When excess hydrogen needs to be released, the switch is closed to allow the hydrogen to be safely discharged to prevent safety risks caused by hydrogen accumulation. The current sensor 10123 is used to detect the stack output current and the net output current of the fuel system. By monitoring the current, the working state of the stack 1011 and the power output of the entire fuel system can be understood, which helps to control and diagnose the system. The protector 10124 can protect the circuit, for example, when the current is too large, the voltage is too high, or other abnormal conditions occur, the circuit is cut off to protect other components in the system from damage.

[0048] In some examples, the fuel cell module 101 further includes a fuel cell control unit 1013:

[0049] The fuel cell control unit 1013 is configured to calculate a stack power based on the bus voltage and the stack output current, and calculate a fuel cell system power based on the bus voltage and the fuel cell system net output current. The fuel cell control unit 1013 is further configured to transmit the stack power and the fuel cell system power to a vehicle CAN network.

[0050] For example, the FCCU (Fuel Cell Control Unit 1013) uses a voltage sensor 10122 to monitor the bus voltage. The bus is the main line of power transmission, and detecting the bus voltage can understand the power supply of the entire system, ensuring that the voltage is within the appropriate range to ensure the normal operation of the fuel cell system and other devices connected thereto. The fuel cell control unit 1013 uses a current sensor 10123 to detect the stack output current and the fuel cell system net output current, respectively. By monitoring these current parameters, the working state of the stack 1011 and the power output of the entire fuel cell system can be understood, providing an important basis for the control and management of the system. The fuel cell control unit 1013 calculates the stack power based on the detected bus voltage and stack output current (stack power = bus voltage x stack output current). At the same time, the fuel cell system power is calculated based on the bus voltage and the fuel cell system net output current. Then, the FCCU uploads the stack power and the fuel cell system power to the vehicle CAN network (Controller Area Network), so that other control units and systems of the vehicle can obtain the running state information of the fuel cell system, in order to carry out comprehensive coordination and control.

[0051] In some examples, the fuel cell control unit 1013 is further configured to detect whether the bus voltage is higher than a preset safety threshold when the fuel cell system without DC converter is shut down, and the fuel cell control unit is further configured to close the residual hydrogen discharge switch 10121 when the bus voltage is lower than the preset safety threshold until the bus voltage is lower than the preset safety threshold.

[0052] For example, after the fuel cell system completes shutdown, the FCCU continues to detect the bus voltage through the voltage sensor 10122. If it is detected that the bus voltage is higher than the preset safety threshold, wherein the preset safety threshold is 60V, the FCCU will take measures to reduce the voltage to ensure safety. The specific operation is to close the residual hydrogen discharge switch 10121. After the residual hydrogen discharge switch 10121 is closed, the voltage generated by the residual hydrogen reaction in the system is discharged through the resistance. Through this discharge process, the bus voltage is reduced to below 60V, the safety voltage. The purpose of this is to avoid the risk of high voltage caused by residual hydrogen reaction after the system is shut down, which may cause electrical failure, fire, explosion and other dangerous situations. Reducing the voltage to a safe range can improve the safety and stability of the system.

[0053] In some examples, the bidirectional DCDC unit 2012 includes a power device 20121 and a high-frequency inductor 20122.

[0054] The power device 20121 is connected in series with the high-frequency inductor 20122, and the power device 20121 is used to step up or step down the bus voltage; the high-frequency inductor 20122 is used to convert the obtained voltage to obtain output power.

[0055] For example, as shown in Figure 4 The structure of the bidirectional DCDC unit in the fuel cell system structure without a direct current converter provided by the embodiment of the application is shown in the structure diagram. The main function of the bidirectional DCDC unit 2012 is to clamp the bus voltage. According to the accelerator pedal of the whole vehicle (which can be understood as the power demand), the target working voltage is set according to the polarization curve of the stack 1011. At this voltage, the stack 1011 can output the corresponding power. The power device 20121 is used for step-up or step-down operation of the bus voltage. When a higher voltage is needed to drive a specific load or perform energy transmission, the power device 20121 can increase the bus voltage; and when it is needed to reduce the voltage to adapt to the requirements of different circuits or devices, it can perform step-down operation. The high-frequency inductor 20122 is used to convert the obtained voltage to obtain output power. When current passes through the high-frequency inductor 20122, it will transform the voltage according to its characteristics. This transformation can include filtering, energy storage and voltage conversion functions. Through the action of the high-frequency inductor 20122, the input voltage is converted into output power suitable for the requirements of a specific load or system.

[0056] In some examples, the power device 20121 includes a first power device 201211 and a second power device 201212.

[0057] The first power device 201211 and the second power device 201212 are connected in series, and when the bus voltage is greater than the target voltage, the power device 20121 steps down the bus voltage, the first power device 201211 is turned on and the second power device 201212 is turned off.

[0058] For example, when the bus voltage is greater than the target voltage, the bus voltage needs to be stepped down. At this time, the power device 20121 steps down the voltage. Specifically, the first power device 201211 is turned on, and the second power device 201212 is turned off. In this way, the bus voltage can be regulated to make the output voltage closer to the target voltage to meet the system requirements.

[0059] In some examples, when the bus voltage is less than the target voltage, the power device 20121 steps up the bus voltage, the first power device 201211 is turned off and the second power device 201212 is turned on.

[0060] For example, when the bus voltage is less than the target voltage, the bus voltage needs to be stepped up to reach the required target voltage value. At this time, the power device 20121 steps up the voltage. Specifically, the first power device 201211 is turned off, and the second power device 201212 is turned on. In this way, when the bus voltage is insufficient, the working state of the power device 20121 can be adjusted to regulate the bus voltage and ensure that the output voltage meets the system requirements.

[0061] In some examples, the bidirectional DCDC unit 2012 further comprises a pre-charge branch relay 20123, a main positive relay 20124, a pre-charge relay 20125 and a pre-charge resistor 20126.

[0062] The pre-charge branch relay 20123 is connected in parallel with the main positive relay 20124, the pre-charge branch relay 20123 is connected in series with the pre-charge resistor 20126, the pre-charge resistor 20126 is connected in series with the pre-charge relay 20125, the pre-charge branch relay 20123 and the pre-charge resistor 20126 are used to limit the size of the charging current flowing into the capacitor, the main positive relay 20124 is connected in series with the pre-charge relay 20125, the main positive relay 20124 is used to provide current for the fuel cell system without a direct current converter when the capacitor charging is completed, and the pre-charge relay 20125 is used to provide a path for the pre-charge current of the capacitor.

[0063] For example, the pre-charge branch relay 20123 is connected in parallel with the main positive relay 20124. The pre-charge branch relay 20123 is further connected in series with a pre-charge resistor 20126, and the pre-charge resistor 20126 is further connected in series with a pre-charge relay 20125. Meanwhile, the main positive relay 20124 is also connected in series with the pre-charge relay 20125.

[0064] The pre-charge branch relay 20123 and the pre-charge resistor 20126 serve to limit the size of the charging current flowing into the capacitor. In the initial stage of starting the circuit, the capacitor is equivalent to a short-circuit state, and a large impact current may be generated if the power supply is directly connected, which may damage the circuit elements. The series connection of the pre-charge branch relay 20123 and the pre-charge resistor 20126 can limit the charging current, so that it slowly rises, thereby protecting the circuit.

[0065] The main positive relay 20124 serves to provide current for the fuel cell system without a DC converter when the capacitor is fully charged. When the capacitor is charged to a certain extent to meet the system requirements, the main positive relay 20124 is closed to provide a large current path required for normal operation.

[0066] The pre-charge relay 20125 serves to provide a path for the pre-charge current of the capacitor. In the pre-charge phase, the pre-charge relay 20125 is closed, so that the current flows through the pre-charge branch relay 20123, the pre-charge resistor 20126, and then charges the capacitor.

[0067] In some examples, when the bus voltage is less than a preset voltage, the pre-charge branch relay 20123 and the pre-charge relay 20125 are both closed to form a pre-charge loop.

[0068] When the bus voltage is greater than or equal to the preset voltage, the pre-charge branch relay 20123 is disconnected and the main positive relay 20124 is closed to provide current for the fuel cell system without a DC converter.

[0069] For example, when the bus voltage is less than a preset voltage, the pre-charge branch relay 20123 and the pre-charge relay 20125 are both closed. At this time, a pre-charge loop is formed, and the purpose is to slowly charge the capacitor and other elements through the loop. Because in the case of low voltage, directly connecting to the main loop may generate a large impact current, which may damage the system elements. The pre-charge resistor 20126 in the pre-charge loop can limit the size of the charging current, ensuring that the charging process is safe and stable.

[0070] The pre-charge branch relay 20123 is opened, and the main positive relay 20124 is closed. At this time, the pre-charge branch is opened, and the fuel cell system without a direct-current converter is provided with current through the main positive relay 20124. Because when the bus voltage reaches the preset value, it indicates that the capacitor and other elements have been charged to the appropriate state, the main circuit can be switched to normal operation, and the main positive relay 20124 can provide a larger current path after being closed, meeting the needs of normal operation of the system.

[0071] In the present disclosure, the terms "first", "second", "third" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance; the term "multiple" refers to two or more, unless otherwise explicitly limited. The terms "mount", "connect", "connect", "fix" and other terms should be broadly understood, for example, "connect" can be fixed connection, or detachable connection, or integrally connected; "connected" can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0072] In the description of the present disclosure, it should be understood that the terms "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the devices or units referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, cannot be understood as a limitation on the present disclosure.

[0073] In the description of the present disclosure, the terms "one embodiment", "some embodiments", "a specific embodiment" and the like mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] In several embodiments provided in the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be omitted or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed each other can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0075] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e. may be located in one place, or may also be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0076] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0077] If the integrated unit is realized in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0078] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0079] Although the preferred embodiments of the present specification have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the present specification.

[0080] Obviously, those skilled in the art can make various modifications and variations to the present specification without departing from the spirit and scope of the present specification. Thus, if these modifications and variations of the present specification fall within the scope of the claims of the present specification and their equivalents, the present specification also intends to include these modifications and variations.

Claims

1. A fuel cell system without a DC converter, characterized in that: The system comprises: A fuel cell module configured to generate electrical energy; the fuel cell module further comprising a fuel cell control unit configured to calculate the stack power based on the bus voltage and the stack output current; the fuel cell control unit further configured to calculate the fuel-electric system power based on the bus voltage and the net output current of the fuel-electric system; and the fuel cell control unit further configured to transmit the stack power and the fuel-electric system power to the vehicle CAN network. The vehicle power module includes a first high-voltage distribution unit, a bidirectional DCDC unit and an energy storage unit. The first high-voltage distribution unit is used to obtain the electrical energy, and the bidirectional DCDC unit is used to realize energy conversion between the first high-voltage distribution unit and the energy storage unit.

2. A fuel cell system without a DC converter according to claim 1, characterized in that: The fuel cell module includes: a fuel cell stack and a second high-voltage power distribution unit; The fuel cell stack is used to obtain chemical energy from fuel and convert the chemical energy into electrical energy according to electrochemical reaction; The second high-voltage power distribution unit is used to distribute the electric energy.

3. A fuel cell system without a DC converter according to claim 2, characterized in that: The second high-voltage power distribution unit includes: a residual hydrogen discharge switch, a voltage sensor, a current sensor, a protector and an integrated air compressor controller; The voltage sensor is connected in parallel with the residual hydrogen discharge switch, and the voltage sensor is used to detect the bus voltage. The residual hydrogen discharge switch is connected in series with the current sensor, and the current sensor is used to detect the output current of the fuel cell stack and the net output current of the fuel cell system. The protector is connected in parallel with the residual hydrogen discharge switch, and the protector is connected in series with the integrated air compressor controller.

4. A fuel cell system without a DC converter according to claim 3, characterized in that: The fuel cell control unit is further configured to detect whether the bus voltage is higher than a preset safety threshold when the fuel cell system without a DC converter is shut down. The fuel cell control unit is further configured to close the residual hydrogen discharge switch when the bus voltage is lower than the preset safety threshold until the bus voltage is lower than the preset safety threshold.

5. A fuel cell system without a DC converter according to claim 3, characterized in that: The bidirectional DCDC unit includes: a power device and a high-frequency inductor; The power device is connected in series with the high-frequency inductor, and the power device is used to step up or down the bus voltage; the high-frequency inductor is used to convert the acquired voltage to obtain output power.

6. A fuel cell system without a DC converter according to claim 5, characterized in that: The power device includes: a first power device and a second power device; The first power device and the second power device are connected in series. When the bus voltage is greater than the target voltage, the power device steps down the bus voltage, the first power device is turned on, and the second power device is turned off.

7. A fuel cell system without a DC converter according to claim 6, characterized in that: When the bus voltage is lower than the target voltage, the power device boosts the bus voltage, the first power device is turned off, and the second power device is turned on.

8. The fuel cell system without a DC converter according to claim 5, characterized in that: The bidirectional DCDC unit further comprises: a pre-charge branch relay, a main positive relay, a pre-charge relay and a pre-charge resistor; The pre-charging branch relay is connected in parallel with the main positive relay, the pre-charging branch relay is connected in series with the pre-charging resistor, the pre-charging resistor is connected in series with the pre-charging relay, the pre-charging branch relay and the pre-charging resistor are used to limit the size of the charging current flowing into the capacitor, the main positive relay is connected in series with the pre-charging relay, the main positive relay is used to provide current to the fuel cell system without a DC converter when the capacitor is fully charged, and the pre-charging relay is used to provide a path for the pre-charging current of the capacitor.

9. A fuel cell system without a DC converter according to claim 8, characterized in that: When the bus voltage is less than a preset voltage, the pre-charging branch relay and the pre-charging relay are both closed to form a pre-charging circuit; When the bus voltage is greater than or equal to a preset voltage, the pre-charge branch relay is disconnected and the main positive relay is closed to provide current to the fuel cell system without a DC converter.

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