KR20060003543A - Fuel cell-supercap hybrid and method of controlling a starting for the same - Google Patents

Abstract

The disclosed fuel cell-supercap hybrid start control method includes the steps of: (a) starting a fuel cell system using an auxiliary battery; (b) checking the start of the fuel cell system with a CAN and connecting a first contactor C1 located at an inverter side (+) terminal; (c) checking the connection of the first contactor (C1) with the can, and then connecting the second contactor (C2) located at a fuel cell side (-) terminal; (d) checking the connection of the second contactor (C2) with the can, and then selecting a first precharge resistor (R1) using the first precharge relay of the supercap initial charging device (C3); (e) after the first precharge resistor R1 confirms the connection with the can, displaying a signal on a dashboard to indicate that the driver can start driving; (f) A few seconds after the initial charging using the first precharge resistor R1 is started, the second precharge resistor R2 is connected using the second precharge relay of the supercap initial charging device C3. Making a step; (g) the first precharge resistor (R1) and the second precharge resistor (R2) are simultaneously connected in parallel and at the same time the supercap initial charging is automatically accelerated; (h) If the initial charging of the supercap is continued while driving and there is almost no voltage difference between the fuel cell and the supercap, the main contactor of the supercap initial charging device C3 is coupled, and then the first and second precharge relays are disconnected. Comprising: while completing the initial charging; characterized in that the included.

According to the present invention, during initial supercap charging through fuel cell power, fuel cell air deficiency due to a charging transient state can be minimized, thereby improving fuel cell life and providing a variable precharge resistance according to the initial supercap state of charge. By using this method, it is possible to quickly complete initial supercap charging while minimizing energy consumption, and by configuring start control to simultaneously perform initial supercap charging and driving by using fuel cell power, it is possible to improve driver's driving convenience. There is this.

Fuel Cell, Supercap, Precharge Relay

Description

FUEL CELL-SUPERCAP HYBRID AND METHOD OF CONTROLLING A STARTING FOR THE SAME}

1 is a circuit diagram schematically showing the configuration of a fuel cell-supercap hybrid according to the present invention.

Figure 2 is a detailed circuit diagram showing the configuration of the supercap initial charging device of Figure 1 in more detail.

Figure 3 is a schematic flow chart showing sequentially a fuel cell-supercap hybrid start control method according to the present invention.

<Description of the symbols for the main parts of the drawings>

10. Fuel Cell

20. Inverter

33. Supercap initial charging device

40. Super Cap

The present invention relates to a fuel cell-supercap hybrid and a start control method thereof, and more particularly, to improve fuel cell life, complete initial supercap charging while minimizing energy consumption, and improve driver's driving comfort. The present invention relates to a fuel cell-supercap hybrid and a start control method thereof.

In the conventional fuel cell-battery hybrid, a high voltage DC-DC converter is positioned between the fuel cell and the battery to buffer the voltage difference between the fuel cell and the battery, and performs charge / discharge control of the battery or power control of the fuel cell. No special start-up control strategy is needed to match the battery voltage.

In the fuel cell-supercap hybrid using the high voltage DC-DC converter, the supercap initial charging and charging / discharging are performed in an active manner using the high voltage DC-DC converter, thus requiring a separate specialized start control strategy. Do not.

On the other hand, in a fuel cell-supercap hybrid without using a high voltage DC-DC converter, it is necessary to develop a separate supercap initial charging device and a corresponding start control for matching the fuel cell and the supercap voltage. As a supercap initial charging device, a type using a single precharge resistor and a precharge relay or an inductor and an insulated gate bipolar transistor (hereinafter referred to as IGBT) are used. Converter type or the like can be referred to as an applicable device.

 However, the fuel cell-battery or fuel cell-supercap hybrid using the high-voltage DC-DC converter is a DC-DC converter having an average efficiency of about 90%. The disadvantage is that the efficiency is not high.

The fuel cell-supercap hybrid without the use of a high voltage DC-DC converter has the advantage of high overall system efficiency.However, the initial supercap charging time and fuel cell are determined by the type and control method of the initial supercap charging device and a parallel start-up control strategy. It affects stack life, energy consumption, system stability (electrical shock when combined with fuel cells and supercaps) and driver comfort.

For example, when a supercap initial charging device using one precharge resistor is used, when the precharge resistance is large, the supercap may be initially charged while preventing the fuel cell air starvation. The initial charging time is long, there is a disadvantage that the energy consumed through the resistor increases. That is, the efficiency of the system is reduced.

On the contrary, when the precharge resistance is small, there is an advantage of reducing the initial charge time of the supercap, but there is a disadvantage in that fuel cell air deficiency is likely to occur. That is, the fuel cell life may be adversely affected.

The present invention was created in order to solve the above problems, to minimize fuel cell air deficiency due to the charging transient state to improve fuel cell life, and to consume energy by using a variable precharge resistance according to the supercap initial charge state. The purpose of the present invention is to provide a fuel cell-supercap hybrid and its start control method capable of performing initial supercap charging and driving at the same time by using fuel cell power.

The fuel cell-supercap hybrid of the present invention for achieving the above object, in the fuel cell-supercap hybrid, the first and second contactors (C1, C2) provided between the fuel cell and the inverter; And a supercap initial charging device (C3) connected to the first and second contactors and the supercap and installed.

A fuel cell-supercap hybrid start control method of the present invention for achieving the above object comprises the steps of: (a) starting the fuel cell system using an auxiliary battery; (b) checking the start of the fuel cell system with a CAN and connecting a first contactor C1 located at an inverter side (+) terminal; (c) checking the connection of the first contactor (C1) with the can, and then connecting the second contactor (C2) located at a fuel cell side (-) terminal; (d) checking the connection of the second contactor (C2) with the can, and then selecting a first precharge resistor (R1) using the first precharge relay of the supercap initial charging device (C3); (e) after the first precharge resistor R1 confirms the connection with the can, displaying a signal on a dashboard to indicate that the driver can start driving; (f) A few seconds after the initial charging using the first precharge resistor R1 is started, the second precharge resistor R2 is connected using the second precharge relay of the supercap initial charging device C3. Making a step; (g) the first precharge resistor (R1) and the second precharge resistor (R2) are simultaneously connected in parallel and at the same time the supercap initial charging is automatically accelerated; (h) If the initial charging of the supercap is continued while driving and there is almost no voltage difference between the fuel cell and the supercap, the main contactor of the supercap initial charging device C3 is coupled, and then the first and second precharge relays are disconnected. Comprising: while completing the initial charging; characterized in that the included.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a circuit diagram schematically showing the configuration of a fuel cell-supercap hybrid according to the present invention.

Referring to the drawings, the fuel cell-supercap hybrid according to the present invention does not use a separate DC-DC converter between the fuel cell 10 and the supercap 40, and the supercap charge / discharge control is performed by the fuel cell 10. Or it is a type using a method that is automatically implemented by the voltage (Fluctuation) of the inverter 20.

In such a fuel cell-supercap hybrid, it is essential to develop a supercap initial charging strategy and a corresponding start control strategy to match the voltages of the fuel cell 10 and the supercap 40 at vehicle startup.

Accordingly, the fuel cell-supercap hybrid according to the present invention includes first and second contactors C1 and C2 31 and 32 provided between the fuel cell 10 and the inverter 20, and the first and second contacts. It is connected to the contactor (31,32) and the super cap 40 is configured to include a supercap initial charging device (C3) 33 installed.

In addition, as shown in FIG. 2, the supercap initial charging device C3 includes two first and second precharge resistors R1 and R2 33a and 33b and the first and second precharge resistors 3. The first and second precharge relays 33d and 33e and the main contactor 33c for connecting the R1 and R2 (33a, 33b) according to the starting situation.

In addition, the first and second contactors C1 and C2 31 and 32 and the supercap initial charging device C3 33 are packaged into a single module, and thus packaged into a single module to be a PDU (Power Disconnect Unit). Is used.

Referring to the start control method of the fuel cell-supercap hybrid according to the present invention having the configuration as described above are as follows.

3 is a schematic flowchart showing a fuel cell-supercap hybrid start control method according to the present invention in sequence.

Referring to the drawings, in the fuel cell-supercap hybrid start control method according to the present invention, first, the fuel cell system is started using an auxiliary battery (step 110).

Subsequently, after confirming that the fuel cell system is started with a CAN (hereinafter referred to as a CAN), the first contactor C1 31 located at the positive terminal of the inverter 20 side is connected. 120)

After confirming that the first contactor (C1) 31 is connected to the CAN, the second contactor (C2) 32 located at the negative terminal of the fuel cell 10 is connected (step 130).

In addition, after confirming the connection of the second contactor (C2) 32 with CAN, the first precharge relay 33d of the supercap initial charging device (C3) 33 disposed on the supercap side (+) terminal is used. The first precharge resistor (R1) 33a is selected.

The first precharge resistor R1 (2 to 100Ω) 33a has a larger resistance value than the second precharge resistor R2 (0.5 to 5Ω) 33b and has a power value of the fuel cell 10. When the initial charge of the supercap 40 using the, to prevent electric shock due to their voltage difference.

In addition, the power of the fuel cell 10 may be excessively instantaneously excessively used to charge the supercap 40 (in this case, air deficiency may occur in the fuel cell stack, which may adversely affect the life of the fuel cell stack). Designed to focus on peak power dissipation.

Subsequently, after confirming that the first precharge resistor (R1) 33a is connected to the CAN, for example, a signal indicating system ready is displayed on the dashboard, indicating that the driver may start driving. )

Accordingly, as the driver starts driving, the power loss through the first precharge resistor (R1) 33a is taken through the above-described method in step 140, and the supercap 40 is powered by the fuel cell 10 power. At the same time as initial charging is started, power for driving the inverter 20 is supplied.

In the present invention, wait until the initial completion of the supercap 40 is not a way to allow the driver to start driving (in this case, the start time may take about 3 minutes or more, which is bad for driving convenience Influences), the first pre-charge resistor (R1) (33a) can be performed at the same time during the initial charging while driving, it is possible to improve the convenience of the driver.

After a few seconds (less than about 10 seconds) of initial charging using the first precharge resistor (R1) 33a, the second precharge relay 33e of the supercap initial charging device (C3) 33 is turned off. Connect the second precharge resistor (R2) 33b (step 160).

At this time, the first precharge relay 33d is continuously connected, and the total precharge resistance is 1 / (1 / R1 + 1 / R2), and the second precharge resistor R2 (33b) having a small resistance value is present. It is set to a value close to).

The reason for using each of the first and second precharge relays 33d and 33e instead of using one precharge relay that can select three positions R1, R2, and Off is the first precharge resistor R1 (33a). ), When the second precharge resistor (R2) 33b is changed to the second precharge resistor (R2) 33b, the first precharge resistor (R1) 33a is temporarily disconnected (off state) occurs.

In this situation, when the second precharge resistor (R2) 33b is coupled, the above-described electric shock and air deficiency of the fuel cell stack may occur in step 140.

The purpose of the second precharge resistor (R2) 33b is to reduce the voltage difference between the fuel cell 10 and the supercap 40 through the first precharge resistor (R1) 33a. This is to accelerate the initial charge time by using a small value resistor. Therefore, the second precharge resistor (R2) 33b is designed with focus on the mean power.

In addition, the first precharge resistor (R1) 33a and the second precharge resistor (R2) 33b are simultaneously connected in parallel, and at the same time, the initial charging of the supercap 40 is automatically accelerated (depending on driving conditions). The total initial charge time can be shortened to less than 1 minute) (step 170).

In particular, since the amount of heat generated by the energy consumed by the first precharge resistor R1 33a and the second precharge resistor R2 33b is not small at this stage (the fuel cell 10 and the supercap 40 are Depending on voltage and power specifications), configuration of air-cooled or water-cooled cooling loops is required.

When the initial charging of the supercap 40 is continued while driving, when there is almost no voltage difference between the fuel cell 10 and the supercap 40 (less than 2V), the main contactor 33c of the supercap initial charging device c3 (33). Then, the first and second precharge relays 33d and 33e are disconnected to complete initial charging.

As described above, the fuel cell-supercap hybrid and its starting control method according to the present invention have the following effects.

In the initial charging of the supercap through fuel cell power, fuel cell air shortage due to the charging transient state is minimized, thereby improving fuel cell life.

In addition, by using a variable precharge resistance according to the initial charge state of the supercap, it is possible to quickly complete the initial supercap charging while minimizing energy consumption.

In addition, as the start control is configured to simultaneously perform initial charging and driving of the supercap by using fuel cell power, driving convenience of the driver may be improved.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (6)

In a fuel cell-supercap hybrid, First and second contactors C1 and C2 installed between the fuel cell and the inverter; And a supercap initial charging device (C3) connected to and connected to the first and second contactors and the supercap. The method of claim 1, The supercap initial charging device (C3), It consists of two first and second precharge resistors R1 and R2 and first and second precharge relays and a main contactor for connecting the first and second precharge resistors R1 and R2 according to a starting condition. A fuel cell-supercap hybrid, characterized in that. The method of claim 1, The first and second contactors (C1, C2) and the supercap initial charging device (C3) is a fuel cell-supercap hybrid, characterized in that packaged as a single module. (a) starting the fuel cell system using an auxiliary battery; (b) checking the start of the fuel cell system with a CAN and connecting a first contactor C1 located at an inverter side (+) terminal; (c) checking the connection of the first contactor (C1) with the can, and then connecting the second contactor (C2) located at a fuel cell side (-) terminal; (d) checking the connection of the second contactor (C2) with the can, and then selecting a first precharge resistor (R1) using the first precharge relay of the supercap initial charging device (C3); (e) after the first precharge resistor R1 confirms the connection with the can, displaying a signal on a dashboard to indicate that the driver can start driving; (f) A few seconds after the initial charging using the first precharge resistor R1 is started, the second precharge resistor R2 is connected using the second precharge relay of the supercap initial charging device C3. Making a step; (g) the first precharge resistor (R1) and the second precharge resistor (R2) are simultaneously connected in parallel and at the same time the supercap initial charging is automatically accelerated; (h) If the initial charging of the supercap is continued while driving and there is almost no voltage difference between the fuel cell and the supercap, the main contactor of the supercap initial charging device C3 is coupled, and then the first and second precharge relays are disconnected. While completing the initial charging while charging; fuel cell-supercap hybrid start control method characterized in that it comprises a. The method of claim 4, wherein The first precharge resistor (R1) has a larger resistance value than the second precharge resistor (R2) characterized in that the fuel cell-supercap hybrid start control method. The method of claim 4, wherein In the step (f), the first precharge relay is continuously connected, and the total precharge resistance is 1 / (1 / R1 + 1 / R2), which is close to the second precharge resistor R2. A fuel cell-supercap hybrid start control method, characterized in that set to a value.

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