Configuration and control method for power conversion device for hydrogen fuel cell of hydrogen locomotive

Abstract

The present invention relates to a configuration and control method for a power conversion device for a hydrogen fuel cell of a hydrogen locomotive, in which the power conversion device for a hydrogen fuel cell of a hydrogen locomotive comprises a triple-active-bridge (TAB) converter to electrically insulate a hydrogen fuel cell and a battery. According to the present invention, the hydrogen fuel cell and the battery are both electrically insulated, thus enhancing system reliability, and are both controllable under the operating conditions of railroad vehicles.

Description

Configuration and control method of a power converter for hydrogen fuel cells in hydrogen locomotives

[0001] The present invention relates to the configuration and control method of a power converter for a hydrogen fuel cell of a hydrogen locomotive.

[0002] According to the prior art, a hydrogen railway vehicle includes a hydrogen fuel cell, a battery, a DC / DC converter for the hydrogen fuel cell, a DC / DC converter for propulsion, a propulsion inverter, and a motor, and FIG. 1 illustrates a main device connection diagram of a hydrogen railway vehicle.

[0003] Since the output voltage of fuel cells is low and voltage fluctuations are significant, DC / DC converters are used to ensure a stable voltage supply; non-isolated DC / DC converters are primarily used due to their simple structure and ease of control. Batteries are used to compensate for the inadequate dynamic characteristics of hydrogen fuel cells and to store regenerative power from railway vehicles. The power from the hydrogen fuel cells and batteries is stepped up through a propulsion DC / DC converter and supplied to the propulsion inverter at an appropriate DC voltage.

[0004] As railway vehicle propulsion systems are high-power devices, the parallel connection of hydrogen fuel cells is unavoidable to output power ranging from hundreds of kW to several MW. While there are no particular problems when using hydrogen fuel cells and non-isolated DC / DC converters individually, when hydrogen fuel cells and non-isolated DC / DC converters are connected in parallel, the hydrogen fuel cells and DC / DC converters share a common ground, which reduces the insulation resistance of the hydrogen fuel cells. This reduction in insulation resistance can lead to problems such as electric shock, fire, system performance degradation, and damage to electronic components.

[0005] Furthermore, in railway vehicle design environments with space constraints, the use of high-power-density lithium-ion batteries is required for long-distance operation; however, since lithium-ion batteries pose a risk of fire and safety accidents, electrical insulation from other electrical components must be considered.

[0006] The present invention aims to solve the problems of the aforementioned prior art by proposing a flash memory including an in-memory processing unit internally and a processing unit for a personal computing device using the same.

[0007] The present invention is proposed based on the aforementioned background and aims to provide a configuration and control method for a power converter for a hydrogen fuel cell of a hydrogen locomotive that can improve system reliability by electrically insulating both the hydrogen fuel cell and the battery.

[0008] However, the technical problem that this embodiment aims to solve is not limited to the technical problem described above, and other technical problems may exist.

[0009] The power converter for a hydrogen fuel cell of a hydrogen locomotive according to the present invention is characterized by including a Triple-Active-Bridge (TAB) converter to electrically insulate the hydrogen fuel cell and the battery.

[0010] The above TAB converter includes a bridge (second bridge) between the hydrogen fuel cell and the propulsion DC / DC converter, and a bridge (third bridge) between the battery and the propulsion DC / DC converter.

[0011] The above TAB converter transmits power between bridges based on the phase of the reference bridge connected to the above-mentioned propulsion DC / DC converter, through the difference between the phase of the second bridge and the phase of the third bridge.

[0012] A control method for a power converter for a hydrogen fuel cell of a hydrogen locomotive, performed by a power conversion control system for a hydrogen fuel cell of a hydrogen locomotive according to the present invention, comprises: (a) a step of configuring a power converter for a hydrogen fuel cell of a hydrogen locomotive including a TAB converter; and (b) a step of controlling the power converter to transmit power during propulsion operation or regenerative operation.

[0013] Step (a) above comprises the TAB converter including a bridge between the hydrogen fuel cell and the propulsion DC / DC converter, and a bridge between the battery and the propulsion DC / DC converter.

[0014] Step (b) above outputs a current command of the propulsion DC / DC converter and converts it into a power command; determines the power command of the hydrogen fuel cell based on the VI curve of the hydrogen fuel cell and the railway vehicle operating conditions; determines the difference between the power command of the propulsion DC / DC converter and the power command of the hydrogen fuel cell as the power command of the battery; and outputs phase commands for the bridge between the hydrogen fuel cell and the propulsion DC / DC converter and the bridge between the battery and the propulsion DC / DC converter.

[0015] In step (b) above, when the propulsion operation is performed in which only the hydrogen fuel cell generates power, the battery does not perform charging or discharging.

[0016] In step (b) above, when the propulsion operation generates power solely from the battery, power is supplied to the propulsion DC / DC converter through the adjustment of the battery's C-rate.

[0017] In step (b) above, when the power of the propulsion DC / DC converter is less than the rated power of the hydrogen fuel cell during propulsion operation, the hydrogen fuel cell charges the battery with the remaining power after delivering it to the propulsion DC / DC converter.

[0018] In step (b) above, during regenerative operation, the regenerative power of the DC / DC converter is entirely transferred to the battery.

[0019] According to the present invention, it is possible to improve system reliability by electrically insulating both the hydrogen fuel cell and the battery, and it can be confirmed that both are controlled under railway vehicle operating conditions.

[0020] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0021] Figure 1 illustrates the connection diagram of the main devices of a hydrogen railway vehicle.

[0022] FIG. 2 illustrates a power conversion device for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention.

[0023] FIG. 3 illustrates a control algorithm for a power converter for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention.

[0024] FIG. 4 illustrates a control method for a power converter for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention.

[0025] Figure 5 is a simulation result of propulsion operation (hydrogen fuel cell and battery power generation) according to an embodiment of the present invention.

[0026] Figure 6 is a simulation result of propulsion operation (power generation using only hydrogen fuel cells) according to an embodiment of the present invention.

[0027] Figure 7 is a simulation result of propulsion operation (power generation using only the battery) according to an embodiment of the present invention.

[0028] Figure 8 is a simulation result of propulsion operation (hydrogen fuel cell power generation, battery charging) according to an embodiment of the present invention.

[0029] Figure 9 is a simulation result of regenerative operation (battery only charging) according to an embodiment of the present invention.

[0030] FIG. 10 is a block diagram showing a computer system for implementing a method according to an embodiment of the present invention.

[0031] The aforementioned objectives of the present invention, as well as other objectives, advantages, and features, and the methods for achieving them, will become clear from the embodiments described in detail below together with the accompanying drawings.

[0032] However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms, and the following embodiments are provided merely to easily inform those skilled in the art of the purpose, structure, and effects of the invention, and the scope of the rights of the present invention is defined by the description in the claims.

[0033] Meanwhile, the terms used in this specification are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used in this specification, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0034] In order to assist those skilled in the art in understanding, the background of the proposed invention will be explained below, and embodiments of the invention will be described.

[0035] Hydrogen fuel cell-based railway vehicle propulsion systems are high-power devices that require the use of multiple fuel cells in parallel. Generally, because the output voltage of hydrogen fuel cells is low and voltage fluctuations are large, DC / DC converters are used to output a stable voltage. To meet the output power requirements, it is inevitable for hydrogen locomotive propulsion systems to use multiple hydrogen fuel cells connected in parallel. However, when hydrogen fuel cells and DC / DC converters are connected in parallel, the hydrogen fuel cells and DC / DC converters share a common ground, which reduces the insulation resistance of the hydrogen fuel cells. Consequently, problems such as the risk of electric shock, fire, system performance degradation, and damage to electronic components may occur.

[0036] To ensure system reliability, when hydrogen fuel cells are used in parallel, an isolated DC / DC converter must be used. When an isolated DC / DC converter is used, the grounds of the hydrogen fuel cell and the DC / DC converter are separated, so the insulation resistance of the hydrogen fuel cell is not reduced.

[0037] Since hydrogen fuel cells are capable of generating electricity, hydrogen fuel cell-based railway vehicle propulsion systems utilize both hydrogen fuel cells and batteries to consider the operational efficiency of railway vehicles. Furthermore, given the space constraints and long-distance operation of railway vehicles, using high-power-density lithium-ion batteries poses a risk of fire and safety accidents; therefore, to ensure system stability, a DC / DC converter capable of electrical isolation must be used.

[0038] According to an embodiment of the present invention, a power conversion device for a hydrogen fuel cell of a hydrogen locomotive including a TAB (Triple-Active-Bridge) converter and a control method thereof are proposed, which has the advantage of being able to electrically isolate the hydrogen fuel cell and the battery, respectively.

[0039] FIG. 2 illustrates a power conversion device for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention.

[0040] The power converter for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention uses a TAB converter. The TAB converter is a power converter structure and is mainly used in high-voltage / high-output applications. The TAB converter has a structure in which three H-bridges are connected to a transformer, and each H-bridge generates an AC voltage through high-frequency switching and converts the voltage through the transformer. The switching operation of each bridge can be controlled by a relative phase difference, and by adjusting the phase difference, a desired output voltage and current can be obtained, and it is possible to adjust the flow of power according to load conditions.

[0041] TAB is a structure in which three H-bridges are connected to a high-frequency transformer with three windings, making it possible to electrically isolate all three electrical components connected to the H-bridges. Therefore, even with the parallel connection of hydrogen fuel cells, the insulation resistance is not reduced, and the battery is electrically isolated from other electrical components, making it possible to improve the reliability of the system.

[0042] Referring to FIG. 2, the TAB converter includes three bridges, and when the phase of the bridge connected to the propulsion DC / DC converter (230) is the reference, it is possible to freely transfer power between the three bridges through the difference between the phase (ΦFC_DC) between the reference phase and the hydrogen fuel cell (210) bridge and the phase (ΦBAT_DC) of the battery (220) bridge.

[0043] Referring to FIG. 2, the hydrogen fuel cell (210) can generate power and outputs power only during propulsion, and the battery (220) and propulsion DC / DC converter (230) deliver power during both propulsion and regeneration.

[0044] FIG. 3 is a flowchart illustrating a control algorithm for a power converter for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention, and FIG. 4 is a flowchart illustrating a control method for a power converter for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention.

[0045] According to an embodiment of the present invention, the upper controller is classified into an upper controller and a lower controller, the upper controller aims to control the input voltage (VDC) of the propulsion DC / DC converter (230), outputs a current command (I*DC) to the lower controller, and the current command is converted into a power command (P*DC) by multiplying it by the VDC (S410).

[0046] The power command (P*FC) of the hydrogen fuel cell (210) is determined by the VI curve of the hydrogen fuel cell (210) and the railway vehicle operating conditions (S420). The hydrogen fuel cell (210) can output up to the rated power during propulsion operation and is controlled to 0 during regenerative operation.

[0047] The power command (P*BAT) of the battery (220) is determined by the difference between P*DC and P*FC (S420), and the outputs of the two current controllers output the phase command (ΦFC_DC) of the hydrogen fuel cell (210) and propulsion DC / DC converter (230) bridge and the phase command (Φ BAT_DC) of the battery (220) and propulsion DC / DC converter bridge (230) (S430).

[0048] The control method of the hydrogen fuel cell-based railway vehicle differs depending on the propulsion and regenerative operation, and the control pattern differs depending on the power generation method of the hydrogen fuel cell (210) and battery (220) during propulsion operation.

[0049] 1. Propulsion Operation (Hydrogen Fuel Cell and Battery Power Generation)

[0050] The hydrogen fuel cell power command (P*FC) is determined according to the VI curve of the hydrogen fuel cell (210) and the railway vehicle operating conditions, and the battery power command (P*BAT) is determined by the difference between the power command (P*DC) of the propulsion DC / DC converter (230) and the power command (P*FC) of the hydrogen fuel cell (210).

[0051] 2. Propulsion operation (power generation by hydrogen fuel cell only)

[0052] Only the hydrogen fuel cell (210) supplies power to the propulsion DC / DC converter (230), so the propulsion DC / DC converter (230) cannot transmit more than the maximum power generated by the hydrogen fuel cell (210) to the propulsion inverter, and the battery (220) does not charge or discharge.

[0053] 3. Propulsion operation (battery-only power generation)

[0054] Only the battery (220) supplies power to the propulsion DC / DC converter (230), and if the C-rate of the battery (220) is increased, the battery (220) alone can fully supply power to the propulsion DC / DC converter (230), and the hydrogen fuel cell (210) does not generate power.

[0055] 4. Propulsion operation (hydrogen fuel cell power generation, battery charging)

[0056] When the power of the propulsion DC / DC converter (230) is less than the rated power of the hydrogen fuel cell (210), the hydrogen fuel cell (210) delivers power to the propulsion DC / DC converter (230) and charges the battery with the remaining power.

[0057] 5. Regenerative driving (charges battery only)

[0058] Since the hydrogen fuel cell (210) is capable of only generating power, all regenerative energy during regenerative operation is charged by the battery (220).

[0059] The scenario according to the embodiment of the present invention was performed under the conditions shown in the following [Table 1].

[0060] [Table 1]

[0061]

[0062] FIG. 5 is a simulation result of propulsion operation (hydrogen fuel cell and battery power generation) according to an embodiment of the present invention, FIG. 6 is a simulation result of propulsion operation (hydrogen fuel cell only power generation) according to an embodiment of the present invention, FIG. 7 is a simulation result of propulsion operation (battery only power generation) according to an embodiment of the present invention, FIG. 8 is a simulation result of propulsion operation (hydrogen fuel cell power generation, battery charging) according to an embodiment of the present invention, and FIG. 9 is a simulation result of regenerative operation (battery only charging) according to an embodiment of the present invention.

[0063] VdcP_C1 is the propulsion DC / DC voltage, P_DC is the propulsion DC / DC power, P_FC is the hydrogen fuel cell power, and P_BAT is the battery power.

[0064] 1. Propulsion Operation (Hydrogen Fuel Cell and Battery Power Generation)

[0065] Referring to Figure 5, a ramp load was applied from 1s to 3s in the simulation, and it was confirmed that both the hydrogen fuel cell and the battery produced power and delivered the rated power of 125kW to the propulsion DC / DC converter.

[0066] 2. Propulsion operation (power generation by hydrogen fuel cell only)

[0067] Depending on the operating conditions of the railway vehicle, the hydrogen fuel cell-based propulsion system must be capable of generating power solely from the fuel cell. Referring to Figure 6, it can be confirmed through simulation that there is no power generated from the battery, and only the hydrogen fuel cell delivers power to the propulsion DC / DC converter.

[0068] 3. Propulsion operation (battery-only power generation)

[0069] Referring to Fig. 7, the simulation results for the case where only the battery generates power during propulsion operation are shown. It can be seen that there is no power generated by the fuel cell, and only the battery generates power and delivers it to the propulsion DC / DC converter.

[0070] 4. Propulsion operation (hydrogen fuel cell power generation, battery charging)

[0071] Referring to Fig. 8, simulation results for hydrogen fuel cell power generation and battery charging are shown. It is possible to manage the SoC by supplying the power required for the propulsion DC / DC converter from the hydrogen fuel cell and sending the surplus power to the battery to charge the battery.

[0072] 5. Regenerative driving (charges battery only)

[0073] Referring to Fig. 9, the simulation results of charging the battery with regenerative power during regenerative operation are illustrated. During the regenerative operation of the railway vehicle, power is transferred from the propulsion DC / DC converter to a hydrogen fuel cell or battery power source. Since the hydrogen fuel cell can only generate power and cannot receive regenerative power, all regenerative power generated during regenerative operation is transferred to the battery. Through the simulation, it can be confirmed that all power from the propulsion DC / DC converter is transferred to the battery.

[0074] According to an embodiment of the present invention, it is applicable to fields using TAB converters, hydrogen fuel cell-based railway vehicle power conversion devices, and fields with multiple power sources.

[0075] A control method for a power conversion device for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention is performed by a power conversion control system for a hydrogen fuel cell of a hydrogen locomotive.

[0076] A control method for a power converter for a hydrogen fuel cell of a hydrogen locomotive, performed by a power conversion control system for a hydrogen fuel cell of a hydrogen locomotive according to an embodiment of the present invention, comprises: (a) a step of configuring a power converter for a hydrogen fuel cell of a hydrogen locomotive including a TAB converter; and (b) a step of controlling the power converter to transmit power during propulsion operation or regenerative operation.

[0077] (a) Step comprises a TAB converter including a bridge between the hydrogen fuel cell and the propulsion DC / DC converter, and a bridge between the battery and the propulsion DC / DC converter.

[0078] Step (b) outputs a current command for the propulsion DC / DC converter and converts it into a power command; determines the power command of the hydrogen fuel cell based on the VI curve of the hydrogen fuel cell and the railway vehicle operating conditions; determines the difference between the power command of the propulsion DC / DC converter and the power command of the hydrogen fuel cell as the power command of the battery; and outputs phase commands for the bridge between the hydrogen fuel cell and the propulsion DC / DC converter and the bridge between the battery and the propulsion DC / DC converter.

[0079] (b) In step (b), when the propulsion operation is performed using only the hydrogen fuel cell, the battery does not perform charging or discharging.

[0080] (b) In step (b), during propulsion operation where only the battery generates power, power is supplied to the propulsion DC / DC converter through the adjustment of the battery's C-rate.

[0081] (b) In step (b), when the power of the propulsion DC / DC converter is less than the rated power of the hydrogen fuel cell during propulsion operation, the hydrogen fuel cell charges the battery with the power remaining after supplying it to the propulsion DC / DC converter.

[0082] (b) In step (b), during regenerative operation, the regenerative power of the DC / DC converter is entirely transferred to the battery.

[0083] FIG. 10 is a block diagram showing a computer system for implementing a method according to an embodiment of the present invention.

[0084] Referring to FIG. 10, a computer system (1300) may include at least one of a processor (1313), memory (1330), an input interface device (1350), an output interface device (1360), and a storage device (1340) that communicate via a bus (1370). The computer system (1300) may also include a communication device (1320) coupled to a network. The processor (1310) may be a central processing unit (CPU) or a semiconductor device that executes instructions stored in memory (1330) or storage device (1340). Memory (1330) and storage device (1340) may include various forms of volatile or non-volatile storage media. For example, memory may include read-only memory (ROM) and random access memory (RAM). In the embodiments of this description, memory may be located inside or outside the processor, and memory may be connected to the processor through various known means. Memory is a volatile or non-volatile storage medium of various forms, and for example, memory may include read-only memory (ROM) or random access memory (RAM).

[0085] Accordingly, embodiments of the present invention may be implemented as a method implemented on a computer or as a non-transient computer-readable medium storing computer-executable instructions. In one embodiment, when executed by a processor, the computer-readable instructions may perform a method according to at least one aspect of the present description.

[0086] The communication device (1320) can transmit or receive wired or wireless signals.

[0087] In addition, the method according to an embodiment of the present invention may be implemented in the form of program instructions that can be executed through various computer means and may be recorded on a computer-readable medium.

[0088] The above computer-readable medium may include program instructions, data files, data structures, etc., either individually or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for embodiments of the present invention, or they may be known and available to a person skilled in the art of computer software. The computer-readable recording medium may include a hardware device configured to store and execute program instructions. For example, the computer-readable recording medium may be magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; ROM; RAM; flash memory, etc. The program instructions may include not only machine code, such as that generated by a compiler, but also high-level language code that can be executed by a computer through an interpreter, etc.

[0089] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. In Paragraph 1, The above TAB converter includes a bridge (second bridge) between the hydrogen fuel cell and the propulsion DC / DC converter, and a bridge (third bridge) between the battery and the propulsion DC / DC converter. Power converter for hydrogen fuel cells in hydrogen locomotives.

2. In Paragraph 2, The above TAB converter transmits power between bridges based on the phase of the reference bridge connected to the above propulsion DC / DC converter, through the difference between the phase of the second bridge and the phase of the third bridge. Power converter for hydrogen fuel cells in hydrogen locomotives.

3. In Paragraph 2, The above TAB converter transmits power between bridges based on the phase of the reference bridge connected to the above propulsion DC / DC converter, through the difference between the phase of the second bridge and the phase of the third bridge. Power converter for hydrogen fuel cells in hydrogen locomotives.

4. A method for controlling a power converter for a hydrogen fuel cell of a hydrogen locomotive, performed by a power conversion control system for a hydrogen fuel cell of a hydrogen locomotive, wherein (a) a step of configuring a power converter for a hydrogen fuel cell of a hydrogen locomotive including a TAB converter; and (b) a step of controlling the power converter to transmit power during propulsion operation or regenerative operation A control method for a power converter for a hydrogen fuel cell of a hydrogen locomotive, including 5. In Paragraph 4, The above step (a) comprises configuring the TAB converter including a bridge between the hydrogen fuel cell and the propulsion DC / DC converter, and a bridge between the battery and the propulsion DC / DC converter. Control method for a power converter for a hydrogen fuel cell in a hydrogen locomotive.

6. In Paragraph 5, Step (b) above outputs a current command of the propulsion DC / DC converter and converts it into a power command; determines the power command of the hydrogen fuel cell based on the VI curve of the hydrogen fuel cell and the railway vehicle operating conditions; determines the difference between the power command of the propulsion DC / DC converter and the power command of the hydrogen fuel cell as the power command of the battery; and outputs phase commands of the bridge between the hydrogen fuel cell and the propulsion DC / DC converter and the bridge between the battery and the propulsion DC / DC converter. Control method for a power converter for a hydrogen fuel cell in a hydrogen locomotive.

7. In Paragraph 6, In step (b) above, when the hydrogen fuel cell is used for propulsion operation, the battery does not perform charging or discharging. Control method for a power converter for a hydrogen fuel cell in a hydrogen locomotive.

8. In Paragraph 6, In step (b) above, when the propulsion operation generates power only from the battery, power is supplied to the propulsion DC / DC converter through the adjustment of the battery's C-rate. Control method for a power converter for a hydrogen fuel cell in a hydrogen locomotive.

9. In Paragraph 6, In step (b) above, when the power of the propulsion DC / DC converter is less than the rated power of the hydrogen fuel cell during propulsion operation, the hydrogen fuel cell charges the battery with the remaining power after delivering it to the propulsion DC / DC converter. Control method for a power converter for a hydrogen fuel cell in a hydrogen locomotive.

10. In Paragraph 6, In step (b) above, during regenerative operation, the regenerative power of the DC / DC converter is entirely transferred to the battery. Control method for a power converter for a hydrogen fuel cell in a hydrogen locomotive.

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