KR102449850B1 - Pre-charge relay control system for fuel cell vehicle and control method of the same - Google Patents

Abstract

a main bus stage connected to the fuel cell stack; at least one stack main relay provided at the main bus stage to connect or block the fuel cell stack and the load connected to the main bus stage; a stack precharge circuit having one end connected to a main bus terminal on the fuel cell stack side and the other end connected to a main bus terminal on the opposite side of the fuel cell stack based on any one of the stack main relays; and a stack precharge relay provided in the stack precharge circuit so that the fuel cell stack and the load are connected or disconnected by bypassing the stack main relay.

Description

Precharge relay system for fuel cell vehicle and its control method

The present invention relates to a precharge relay system for a fuel cell vehicle and a control method thereof, and more particularly, to a stack relay assembly for supplying high voltage power through a stack of a fuel cell vehicle and a high voltage battery and a precharge relay system included in the power relay assembly and to a control method thereof.

A fuel cell system applied to a hydrogen fuel cell vehicle, which is one of the environmentally friendly future vehicles, includes a fuel cell stack that generates electric energy from an electrochemical reaction of a reactive gas, a hydrogen supply device that supplies hydrogen as fuel to the fuel cell stack, An air supply device for supplying air containing oxygen, which is an oxidizing agent required for electrochemical reaction, to the fuel cell stack, and heat that is a by-product of the electrochemical reaction of the fuel cell stack to the outside to optimally control the operating temperature of the fuel cell stack It consists of a thermal and water management system that performs a water management function.

The fuel cell vehicle is equipped with a fuel cell stack and a high voltage battery as a power source for supplying power to a driving motor serving as a driving source, and includes an inverter or the like to drive the driving motor.

1 is a block diagram showing the configuration of a precharge relay system applied to a conventional fuel cell vehicle.

Referring to FIG. 1 , a fuel cell vehicle includes a driving motor 23 driven by receiving power from a fuel cell stack 10 and a high voltage battery 50 , an inverter 22 for driving the driving motor 23 , and fuel and a main load 21 connected to the battery stack 10 and a high voltage load 61 connected to the high voltage battery 50 . In this specification, the main load 21 , the inverter 22 , the driving motor 23 , the high voltage load 61 , the high voltage battery 50 , and the like are collectively referred to as loads.

Here, the high voltage battery 50 includes a power relay assembly (PRA, 70) that switches the power of the high voltage battery 50 to be connected to or cut off from the high voltage load, and the power of the fuel cell stack 10 is and a stack relay assembly (SRA, 30) that switches to be connected to or disconnected from the main bus terminal 20 .

The power relay assembly 70 includes two battery main relays 71 and 72 respectively connected to the positive and negative poles of the high voltage battery 50 and a precharge relay provided in a circuit 73 bypassing the positive battery main relay 71 . (Pre-charge Relay, 74) and a pre-charge resistor (Pre-charge Resistor, 75). The battery main relays 71 and 72 and the precharge relay 74 of the power relay assembly are controlled by a Battery Management System (BMS, 80).

Specifically, when the high voltage battery 50 is electrically connected to the converter 51 , the negative battery main relay 72 and the precharge relay 74 are connected first. Accordingly, since the current output from the high voltage battery 50 flows to the high voltage load 61, the magnitude of the current gradually increases. When the magnitude of the current increases enough not to impact the high voltage load 61 , the positive main relay 71 is connected and then the precharge relay 74 is cut off so that the high voltage battery 50 and the high voltage load 61 are electrically connected to each other. Complete the connection.

In addition, the stack relay assembly 30 includes two main relays 31 and 32 , and the main relays 31 and 32 of the stack relay assembly 30 include a fuel cell control unit (FCU, FCU, 40) is controlled by The conventional stack relay assembly 30 does not include a precharge relay, and the stack relay assembly 30 is operated after the power relay assembly 70 is connected.

In the case of the high voltage circuit unit applied to the conventional fuel cell vehicle, the stack relay and the power relay cannot be controlled to compensate each other, and the stack relay may be operated after the precharge relay included in the power relay assembly is operated. There was a problem that it took a long time until the power generation of the.

3 is a flowchart of a starting sequence applied to a conventional fuel cell vehicle.

Specifically, referring to FIG. 3 , in the related art, when there is a request for a start (S10), while operating the negative battery main relay, the potential of the negative electrode is made 0 [V] through the ground (S20), and then the power relay assembly is provided. After the precharge relay is operated (S30), the battery main relay of the positive pole is activated (S40) and the driving motor is operated by the high voltage battery (S50), the stack main relay provided in the stack relay assembly is operated (S60, S70) Start-up is completed (S80). Therefore, there is a problem that it takes a long time since many steps are sequentially performed to complete the start-up.

In addition, since there is no precharge relay in the stack relay assembly, a high current suddenly flows to the main load directly connected to the stack, and there is a risk of component damage due to inrush current.

The matters described as the background art above are only for improving the understanding of the background of the present invention, and should not be taken as an acknowledgment that they correspond to the prior art already known to those of ordinary skill in the art.

KR 10-2016-0043829 A

The present invention has been proposed to solve this problem, and an object of the present invention is to provide a precharge relay system for a fuel cell vehicle in which a precharge relay is provided in a stack relay assembly and interlocked with a power relay assembly.

According to an aspect of the present invention, there is provided a precharge relay system for a fuel cell vehicle comprising: a main bus terminal connected to a fuel cell stack; at least one stack main relay provided at the main bus stage to connect or block the fuel cell stack and the load connected to the main bus stage; a stack precharge circuit having one end connected to a main bus terminal on the fuel cell stack side and the other end connected to a main bus terminal on the opposite side of the fuel cell stack based on any one of the stack main relays; and a stack precharge relay provided in the stack precharge circuit so that the fuel cell stack and the load are connected or disconnected by bypassing the stack main relay.

The stack main relay may include a first stack main relay provided on a positive electrode of the main bus terminal and a second stack main relay provided on a negative electrode of the main bus terminal, and the stack precharge circuit may be connected to the positive electrode of the main bus terminal.

and a fuel cell controller controlling the stack main relay and the stack precharge relay, wherein the fuel cell controller turns on the stack precharge relay and turns on the stack main relay when there is a request to start the fuel cell vehicle. Although the relay and the stack precharge relay are controlled, when an abnormality is detected in the stack precharge relay, the control may be terminated without turning on the stack main relay.

The load includes a high voltage battery connected to the main bus terminal through a converter, and one or more battery main relays provided between the high voltage battery and the converter to connect or cut off the high voltage battery to the converter.

The battery main relay may include a first battery main relay provided on a positive line between the high voltage battery and the converter and a second battery main relay provided on a negative line between the high voltage battery and the converter.

The stack main relay may include a first stack main relay provided on a positive electrode of the main bus terminal and a second stack main relay provided on a negative electrode of the main bus terminal, and the stack precharge circuit may be connected to the positive electrode of the main bus terminal.

The battery controller further includes a battery controller for controlling the battery main relay, wherein the battery controller controls the battery main relay to turn on the battery main relay after the stack precharge relay is turned on when there is a request to start the fuel cell vehicle, When an abnormality is detected in the charge relay, the control may be terminated without turning on the battery main relay.

One end is connected to the stack precharge circuit on the opposite side of the fuel cell stack based on the stack precharge relay, and the other end is a battery precharge circuit connected to the converter side with respect to the battery main relay in a line between the high voltage battery and the converter. have.

a first resistor provided in the stack precharge circuit on the stack precharge relay side based on a point at which the stack precharge circuit is connected to the battery precharge circuit; and a second resistor provided in the stack precharge circuit opposite to the stack precharge relay based on a point where the stack precharge circuit is connected to the battery precharge circuit.

Resistance values of the first resistor and the second resistor may be set such that a voltage equal to the voltage of the high voltage battery is applied to the second resistor when the stack precharge relay is connected.

a first resistor provided in the battery precharge circuit; and a diode provided in the battery precharge circuit.

According to an aspect of the present invention, there is provided a method for controlling a precharge relay system for a fuel cell vehicle, comprising: grounding a fuel cell stack when there is a request to start the fuel cell vehicle; actuating the stack precharge relay; and actuating the stack main relay; may include

According to an aspect of the present invention, there is provided a method of controlling a precharge relay system for a fuel cell vehicle, comprising: operating a second stack main relay when there is a request to start the fuel cell vehicle; actuating the stack precharge relay; and operating the first stack main relay.

According to an aspect of the present invention, there is provided a method of controlling a precharge relay system for a fuel cell vehicle, comprising: grounding a stack when there is a request to start the fuel cell vehicle; actuating the stack precharge relay; and simultaneously operating the stack main relay and the battery main relay.

According to an aspect of the present invention, there is provided a control method of a precharge relay system for a fuel cell vehicle, comprising: simultaneously operating a second stack main relay and a second battery main relay when there is a request to start the fuel cell vehicle; actuating the stack precharge relay; and operating the first stack main relay and the first battery main relay.

According to the precharge relay system for a fuel cell vehicle of the present invention, the stack relay assembly and the power relay assembly are interlocked and controlled.

In addition, it has an effect of preventing damage to components connected to the main load due to the sudden inflow of current.

In addition, the stack relay and the battery relay operate at the same time, thereby reducing the time it takes to complete the startup.

1 is a block diagram showing the configuration of a precharge relay system applied to a conventional fuel cell vehicle.
2 is a block diagram of a precharge relay system for a fuel cell vehicle according to an exemplary embodiment of the present invention.
3 is a flowchart of a starting sequence applied to a conventional fuel cell vehicle.
4 is a flowchart of a starting sequence applied to a fuel cell vehicle according to an embodiment of the present invention.

Specific structural or functional descriptions of the embodiments of the present invention disclosed in this specification or application are only exemplified for the purpose of describing the embodiments according to the present invention, and the embodiments according to the present invention may be implemented in various forms. and should not be construed as being limited to the embodiments described in the present specification or application.

Since the embodiment according to the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiment according to the concept of the present invention with respect to a specific disclosed form, and should be understood to include all changes, equivalents or substitutes included in the spirit and scope of the present invention.

Terms such as first and/or second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one element from another element, for example, without departing from the scope of the present invention, a first element may be called a second element, and similarly The second component may also be referred to as the first component.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle. Other expressions describing the relationship between elements, such as "between" and "immediately between" or "neighboring to" and "directly adjacent to", etc., should be interpreted similarly.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, and includes one or more other features or numbers. , it should be understood that it does not preclude the existence or addition of steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as meanings consistent with the context of the related art, and unless explicitly defined in the present specification, they are not to be interpreted in an ideal or excessively formal meaning. .

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in each figure indicate like elements.

2 is a block diagram of a precharge relay system for a fuel cell vehicle according to an exemplary embodiment of the present invention.

Referring to FIG. 2 , a precharge relay system for a fuel cell vehicle according to an embodiment of the present invention includes a main bus terminal 200 connected to a fuel cell stack 100 ; at least one or more stack main relays 310 and 320 provided in the main bus terminal 200 to connect or block loads connected to the fuel cell stack 100 and the main bus terminal 200; One end of one of the stack main relays 310 and 320 is connected to the main bus end 200 on the fuel cell stack 100 side, and the other end is connected to the main bus terminal 200 on the opposite side of the fuel cell stack 100 with respect to any one 310 . ) connected to the stack precharge circuit 330; and a stack precharge relay 340 provided in the stack precharge circuit 330 so that the fuel cell stack 100 and the load are connected or disconnected by bypassing the stack main relay 310 .

The stack relay assembly (SRA) 300 includes stack main relays 310 and 320 , a stack precharge circuit 330 , and a stack precharge relay 340 .

In the fuel cell stack 100 , direct current power is generated by a reaction between hydrogen and oxygen. Power generated in the fuel cell stack 100 may be supplied to a load through the main bus terminal 200 connected to the fuel cell stack 100 .

Here, the load refers to the drive motor 230 connected through the inverter 220 , the main load 210 directly connected to the main bus terminal 200 , the high voltage battery 500 connected through the converter 510 , and the difference between the high voltage battery and the converter. It is a concept including all of the high voltage load 610 and the like connected to the line 600 .

At least one or more stack main relays 310 and 320 for connecting or disconnecting the fuel cell stack 100 and the load may be provided at the main bus terminal 200 between the fuel cell stack 100 and the load. Specifically, the stack main relays 310 and 320 connect the first stack main relay 310 provided at the positive electrode of the main bus terminal 200 and the second stack main relay 320 provided at the negative electrode of the main bus terminal 200 to each other. may include

One end of one of the stack main relays 310 and 320 is connected to the main bus end 200 on the fuel cell stack 100 side, and the other end is connected to the main bus terminal 200 on the opposite side of the fuel cell stack 100 with respect to any one 310 . ) connected to the stack precharge circuit 330 and the stack precharge circuit 330 so that the fuel cell stack 100 and the load bypass the stack main relay 310 to be connected or blocked. may include

Specifically, the stack precharge circuit 330 is a circuit that bypasses the stack main relay 310 on the main bus terminal 200 to connect the fuel cell stack 100 and the load, and the stack precharge relay 340 is a stack It may be provided to connect or disconnect the precharge circuit 330 . Resistors 370 and 380 may be provided in the stack precharge circuit 330 . This will be described in detail below.

In the embodiment of FIG. 2 , the stack precharge circuit 330 is configured to be respectively connected to the positive electrode of the main bus terminal 200 so as to bypass the first stack main relay 310 , but on the contrary, the second stack main relay 320 . It may be configured to bypass and be respectively connected to the negative electrode of the main bus terminal 200 .

The stack main relays 310 and 320 and the stack precharge relay 340 may be controlled by a fuel cell control unit (FCU) 400 . When there is a request to start the fuel cell vehicle, the fuel cell controller 400 turns on the stack precharge relay 340 and then turns on the stack main relays 310 and 320 to turn on the stack main relays 310 and 320 and the stack precharge relay. The charge relay 340 may be controlled.

Specifically, in the case of this embodiment, the second stack main relay 320 is controlled to turn on first, and after a time elapses so that sufficient current flows after the stack precharge relay 340 is turned on, the first stack main relay (310) can be turned on. The stack precharge relay 340 may be controlled to be turned off at the same time or after the first stack main relay 310 is turned on.

When an abnormality is detected in the stack precharge relay 340 , the fuel cell controller 400 may terminate the control without turning on the stack main relays 310 and 320 . The fuel cell controller 400 may control the abnormality detected by the stack precharge relay 340 to notify the driver of the abnormality detection through a warning lamp or a beep sound before the control is terminated.

The load includes a high voltage battery 500 connected to the main bus terminal 200 through a converter 510 , and is provided between the high voltage battery 500 and the converter 510 to connect the high voltage battery 500 to the converter 510 . It may include; one or more battery main relays (710, 720) for connecting or disconnecting. The converter exists to convert the voltage difference between the fuel cell stack 100 connected to the main bus terminal 200 and the high voltage battery.

The power relay assembly (PRA, 700) includes one or more battery main relays (710, 720). Specifically, the battery main relays 710 and 720 are connected to the first battery main relay 710 provided on the positive line of the line 600 between the high voltage battery and the converter and the negative line of the line 600 between the high voltage battery and the converter. A second battery main relay 720 provided may be included.

A high voltage load 610 may be connected to the line 600 between the high voltage battery and the converter. Here, the high voltage load 610 is preferably connected to the converter 600 side with reference to the battery main relays 710 and 720 in the line 600 between the high voltage battery and the converter.

The battery main relays 710 and 720 may be controlled by a Battery Management System (BMS, 800). The battery controller 800 may control the battery main relays 710 and 720 to turn on the battery main relays 710 and 720 after the stack precharge relay 340 is turned on when there is a request to start the fuel cell vehicle. have.

If an abnormality is detected in the stack precharge relay 340 , the battery controller 800 may control the battery main relays 710 and 720 to end the control without turning on the battery main relays 710 and 720 . The battery controller 800 may control the abnormality detected by the stack precharge relay 340 to notify the driver of the abnormality detection through a warning lamp or a beep sound before the control ends.

One end is connected to the stack precharge circuit 330 on the opposite side of the fuel cell stack 100 based on the stack precharge relay 340 , and the other end is connected to the battery main relays 710 and 720 in the line 600 between the high voltage battery and the converter. ) based on the battery precharge circuit 350 connected to the converter 510 side; may further include.

The battery precharge circuit 350 is configured so that the stack precharge control is interlocked with the battery precharge. Specifically, when the stack precharge circuit 330 is connected to the positive electrode of the main bus terminal 200 , the battery precharge circuit 350 may also be connected to the positive line of the line 600 between the high voltage battery and the converter.

Conversely, when the stack precharge circuit is connected to the negative electrode of the main bus terminal, the battery precharge circuit may also be connected to the negative line between the high voltage battery and the converter.

A first resistor 370 and a second resistor 380 may be provided in the stack precharge circuit 350 . The first resistor 370 may be provided in the stack precharge circuit 330 on the side of the stack precharge relay 340 based on a point where the stack precharge circuit 350 is connected to the battery precharge circuit 350 , , the second resistor 380 is to be provided in the stack precharge circuit 330 on the opposite side of the stack precharge relay 340 based on the point where the stack precharge circuit 330 is connected to the battery precharge circuit 350 . can

Here, the first resistor 370 and the second resistor 380 have resistance values such that the same voltage as the voltage of the high voltage battery 500 is applied to the second resistor 380 when the stack precharge relay 340 is connected. can be set.

For example, the voltage of the fuel cell stack 100 may be set to 450 [V] and the voltage of the high-voltage battery 500 may be set to 250 [V], and the first resistor 370 and the second resistor 380 may be ) may be determined such that the potential difference between both ends of the second resistor 380 becomes 250 [V] equal to the voltage of the high voltage battery 500 . The resistance value of the third resistor 360 may also be affected, but the effect will not be significant. Therefore, as the resistance values of the first resistor 370 and the second resistor 380 are set, both ends of the second resistor 380 are The potential difference may be equal to the voltage of the high voltage battery 500 .

A third resistor 360 and a diode 390 may be further provided in the battery precharge circuit 350 . The amount of current flowing into the battery precharge circuit 350 may vary according to the size of the third resistor 360 of the battery precharge circuit 350 . According to the configuration of the third resistor 360 and the diode 390 , the reverse current may be prevented from flowing in the battery precharge circuit 350 due to the reverse voltage.

4 is a flowchart of a starting sequence applied to a fuel cell vehicle according to an embodiment of the present invention.

4 , in a method for controlling a precharge relay system of a fuel cell vehicle according to an embodiment of the present invention,

grounding the fuel cell stack when there is a request to start the fuel cell vehicle (S100) (S200); operating the stack precharge relay (S300); and operating the stack main relay (S400) to complete the starting of the fuel cell vehicle (S500).

When there is a request for starting the fuel cell vehicle (S100), the negative potential may be made 0 [V] by grounding the fuel cell stack (S200). It can be connected so that the negative side of the main bus terminal is grounded when there is a request to start the fuel cell vehicle. Specifically, it can be connected so that the negative side of the main bus terminal is grounded through the connection of the stack main relay provided on the negative side of the main bus terminal.

Thereafter, the stack precharge relay is turned on (S300), and after a time elapses so that sufficient current flows, the stack main relay is turned on (S400) to complete the start-up of the fuel cell vehicle. When the stack main relay is operated after the stack precharge relay is operated, the battery main relay may also be operated at the same time (S200).

The stack main relay of the precharge relay system for a fuel cell vehicle according to an embodiment of the present invention includes a first stack main relay provided on a positive electrode of a main bus terminal and a second stack main relay provided on a negative electrode of the main bus terminal, The stack precharge circuit is connected to the positive side of the main bus terminal, and the battery main relay connects the first battery main relay provided on the positive line between the high voltage battery and the converter and the second battery main relay provided on the negative line between the high voltage battery and the converter. In this case, when there is a request to start the fuel cell vehicle (S100), the second stack main relay is operated to connect the negative electrode of the fuel cell stack to ground (S200). Thereafter, the stack precharge relay is turned on ( S300 ), and after a sufficient time has elapsed, the first stack main relay is turned on ( S400 ) to complete the start of the fuel cell vehicle ( S500 ).

The second battery main relay may be simultaneously operated while the second stack main relay is operated (S200), and the first battery main relay may be simultaneously operated while the first stacked main relay is operated (S400).

Although shown and described with respect to specific embodiments of the present invention, it is understood in the art that the present invention can be variously improved and changed without departing from the spirit of the present invention provided by the following claims. It will be obvious to those of ordinary skill in the art.

10: fuel cell stack 20: main bus stage
30: stack relay assembly 40: fuel cell controller
50: high voltage battery 60: line between high voltage battery and converter
70: power relay assembly 80: battery controller
100: fuel cell stack 200: main bus stage
300: stack relay assembly 400: fuel cell controller
500: high voltage battery 600: line between high voltage battery and converter
700: power relay assembly 800: battery controller

Claims (15)

a main bus stage connected to the fuel cell stack;
at least one stack main relay provided at the main bus stage to connect or block the fuel cell stack and the load connected to the main bus stage;
a stack precharge circuit having one end connected to a main bus terminal on the fuel cell stack side and the other end connected to a main bus terminal on the opposite side of the fuel cell stack based on any one of the stack main relays; and
a stack precharge relay provided in the stack precharge circuit so that the fuel cell stack and the load are connected or disconnected by bypassing the stack main relay;
one or more battery main relays connected to the main bus terminal through a converter and provided between the high voltage battery and the converter to connect or disconnect the high voltage battery to the converter; and
A fuel cell comprising a; one end connected to the stack precharge circuit on the opposite side of the fuel cell stack with reference to the stack precharge relay, and the other end connected to the converter side with respect to the battery main relay in a line between the high voltage battery and the converter. The vehicle's precharge relay system. The method according to claim 1,
The stack main relay includes a first stack main relay provided on a positive pole of the main bus terminal and a second stack main relay provided on a negative pole of the main bus terminal,
The stack precharge circuit is a precharge relay system for a fuel cell vehicle, characterized in that it is connected to the positive electrode of the main bus stage. The method according to claim 1,
Further comprising; a fuel cell controller for controlling the stack main relay and the stack precharge relay;
The fuel cell controller controls the stack main relay and the stack precharge relay to turn on the stack main relay after turning on the stack precharge relay when there is a request to start the fuel cell vehicle, but when an abnormality is detected in the stack precharge relay A precharge relay system for a fuel cell vehicle, characterized in that the control is terminated without turning on the stack main relay. delete The method according to claim 1,
The battery main relay includes a first battery main relay provided on a positive line between the high voltage battery and the converter and a second battery main relay provided on a negative line between the high voltage battery and the converter. . 6. The method of claim 5,
The stack main relay includes a first stack main relay provided on a positive pole of the main bus terminal and a second stack main relay provided on a negative pole of the main bus terminal,
The stack precharge circuit is a precharge relay system for a fuel cell vehicle, characterized in that it is connected to the positive electrode of the main bus stage. The method according to claim 1,
A battery controller for controlling the battery main relay; further comprising,
The battery controller controls the battery main relay to turn on the battery main relay after the stack precharge relay is turned on when there is a request to start the fuel cell vehicle. A precharge relay system for a fuel cell vehicle, characterized in that the control is terminated without being controlled. delete The method according to claim 1,
a first resistor provided in the stack precharge circuit on the stack precharge relay side based on a point at which the stack precharge circuit is connected to the battery precharge circuit; and
The precharge relay system of the fuel cell vehicle further comprising a second resistor provided in the stack precharge circuit opposite to the stack precharge relay based on a point where the stack precharge circuit is connected to the battery precharge circuit. 10. The method of claim 9,
A precharge relay system for a vehicle, characterized in that resistance values of the first resistor and the second resistor are set such that a voltage equal to the voltage of the high voltage battery is applied to the second resistor when the stack precharge relay is connected. The method according to claim 1,
a third resistor provided in the battery precharge circuit; and
The precharge relay system for a fuel cell vehicle further comprising a diode provided in the battery precharge circuit. In the method of controlling the precharge relay system of the fuel cell vehicle of claim 1,
grounding the fuel cell stack when there is a request to start the fuel cell vehicle;
actuating the stack precharge relay; and
A method of controlling a precharge relay system of a fuel cell vehicle, comprising: operating a stack main relay. In the method of controlling the precharge relay system of the fuel cell vehicle of claim 2,
operating a second stack main relay when there is a request to start the fuel cell vehicle;
actuating the stack precharge relay; and
A method of controlling a precharge relay system of a fuel cell vehicle, comprising: operating a first stack main relay. In the method of controlling the precharge relay system of the fuel cell vehicle of claim 1,
grounding the stack when there is a request to start the fuel cell vehicle;
actuating the stack precharge relay; and
A method of controlling a precharge relay system of a fuel cell vehicle, comprising: simultaneously operating a stack main relay and a battery main relay. In the method of controlling the precharge relay system of the fuel cell vehicle of claim 6,
simultaneously operating a second stack main relay and a second battery main relay when there is a request to start the fuel cell vehicle;
actuating the stack precharge relay; and
A method of controlling a precharge relay system of a fuel cell vehicle, comprising: operating a first stack main relay and a first battery main relay.

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