JP2021052575A - Electric power system - Google Patents

Abstract

To provide a technique which can operate a cooling device even if a system for driving a secondary cell and a motor fails.SOLUTION: An electric power system is mounted in a fuel cell vehicle with a cooling storage. The electric power system includes: a drive system; a fuel cell system which has a fuel cell which can supply electric power to a drive motor and a cooling device for the cooling storage; a secondary cell which can supply electric power to the drive motor and the cooling device; a relay for the secondary cell which is provided in a first DC conductive wire for connecting the drive motor and the secondary cell and opens/closes an electric contact between the drive motor and the secondary cell; and a control section which detects failures in the fuel cell system, the drive system, and the secondary cell and controls the relay for the secondary cell according to detection results of the failures. The control section closes the relay for the secondary cell and supplies electric power from the secondary cell to the cooling device when detecting the failure of the fuel cell system, and supplies electric power from the fuel cell system to the cooling device when detecting at least one of the secondary cell and the drive system.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to an electric power system.

Fuel cell vehicles equipped with a cooling device for driving a cooler such as a refrigerator or a freezer are known. As the power source of the cooling device, for example, a secondary battery such as a battery which is a power source of the vehicle is used. Patent Document 1 describes a technique for controlling a relay provided between a cooling device and a secondary battery so that electric power can be supplied to the cooling device even when the vehicle is temporarily parked.

Japanese Unexamined Patent Publication No. 2015-31410

If the system that drives the secondary battery or motor fails, the cooling device may not be powered. Therefore, there has been a demand for a technique capable of operating the cooling device even if the secondary battery or the system for driving the secondary battery fails.

The present disclosure has been made to solve the above-mentioned problems, and can be realized in the following forms.

According to one embodiment of the present disclosure, there is provided an electric power system mounted on a fuel cell vehicle provided with a cooler. This electric power system includes a drive system having a drive motor that generates a driving force, a fuel battery system having a fuel battery capable of supplying electric power to the drive motor and a cooling device for a cooler, and the drive motor and the above. A secondary battery capable of supplying power to the cooling device and a first DC lead wire connecting the drive motor and the secondary battery are provided to open and close the electrical contact between the drive motor and the secondary battery. A secondary battery relay, a control unit that detects a failure of the fuel cell system, the drive system, and the secondary battery, and controls opening and closing of the secondary battery relay according to the detection result of the failure. To be equipped. When the control unit detects a failure of the fuel cell system, the control unit closes the relay for the secondary battery, supplies electric power from the secondary battery to the cooling device, and causes the secondary battery and the drive system to be connected to each other. When at least one of the failures is detected, electric power is supplied from the fuel cell system to the cooling device. According to this form of power system, when a failure of the fuel cell system is detected, the relay for the secondary battery is closed, power is supplied from the secondary battery to the cooling device, and at least one of the secondary battery and the drive system is used. When a failure is detected, power is supplied from the fuel cell system to the cooling device, so that the cooling device can be operated reliably.

The present disclosure can be realized in various forms, for example, a fuel cell vehicle provided with an electric power system, a control method of the electric power system, and the like.

It is a figure which shows the schematic structure of the electric power system. It is a flowchart which shows an example of the procedure of a power source setting process. It is a flowchart which shows an example of the procedure of the power source setting process in 2nd Embodiment. This is an example of displaying the available time.

A. First Embodiment:
FIG. 1 is a schematic view showing the configuration of the electric power system 100 in the present embodiment. The electric power system 100 is mounted on a vehicle 101 including a cooling cabinet 102. The electric power system 100 includes a secondary battery 10, a relay 40 for the secondary battery, a drive system 20, a fuel cell system 70, and a control unit 80. The electric power system 100 supplies electric power from the secondary battery 10 to the drive motor 21 that generates the driving force of the vehicle 101 and the cooling device 30 for the cooling cabinet 102. The vehicle 101 of the present embodiment is a fuel cell vehicle, and the drive motor 21 and the cooling device 30 are driven by using the output power of the fuel cell 71 as well as the output power of the secondary battery 10, as will be described later. ..

As the secondary battery 10, for example, a lithium ion battery is used. The secondary battery 10 is connected to the first DC lead wire L1. The first DC lead wire L1 includes a first high voltage side lead wire L1a connected to the positive side terminal of the secondary battery 10 and a first low voltage side lead wire L1b connected to the negative side terminal. The first low voltage side lead wire L1b is connected to the ground. The secondary battery 10 can supply electric power to the drive motor 21 and the cooling device 30 through the first DC lead wire L1.

The drive motor 21 is connected to the drive wheels DW of the vehicle 101 via a gear (not shown), and generates a driving force for rotating the drive wheels DW. The drive motor 21 is composed of, for example, a three-phase AC motor. The power system 100 includes an inverter 22 that mediates the connection between the drive motor 21 and the first DC lead wire L1. The inverter 22 is a DC / AC inverter, and converts the direct current flowing through the first direct current lead wire L1 into three-phase alternating current and outputs it to the drive motor 21. Further, the inverter 22 converts the regenerative power generated by the drive motor 21 into direct current and outputs it to the first direct current lead wire L1. This regenerative power is stored in the secondary battery 10.

The cooling device 30 is connected to the first DC conductor L1 via the second DC conductor L2. The second DC lead wire L2 is connected to the first DC lead wire L1 between the secondary battery relay 40 and the drive motor 21, which will be described later. The second DC lead wire L2 includes a second high voltage side lead wire L2a connected to the first high voltage side lead wire L1a of the first DC lead wire L1 and a second low voltage side lead wire L2b connected to the first low voltage side lead wire L1b. Including. In the present embodiment, the second DC lead wire L2 is connected to the first DC lead wire L1 between the relay 40 for the secondary battery and the smoothing capacitor 52 for the secondary battery.

The cooling device 30 includes a power supply unit 31 connected to the second DC lead wire L2 and a drive unit 32 driven by receiving electric power from the power supply unit 31. The cooling device 30 is driven by a high voltage of 100 V or more. The cooling device 30 controls the temperature inside the cooling cabinet 102 of the vehicle 101 to a predetermined temperature or lower, for example, below freezing point, by driving a compressor or the like included in the driving unit 32. In the present embodiment, the "cooler" is a concept including a refrigerator and a freezer.

The power supply unit 31 of the cooling device 30 includes a diode 33, an internal relay 35, an auxiliary smoothing capacitor 36, and an auxiliary inverter 37. The diode 33 and the internal relay 35 are provided on the second high voltage side lead wire L2a. The diode 33 prevents the backflow of current from the cooling device 30 side to the secondary battery 10 side.

The internal relay 35 is attached to the second high-voltage side lead wire L2a, and connects and disconnects the second high-voltage side lead wire L2a by an opening / closing operation. The internal relay 35 includes a first internal relay switch 35a, a second internal relay switch 35b, a resistance element 35c, and an auxiliary parallel lead wire L2p connected in parallel to the second high voltage side lead wire L2a. The first internal relay switch 35a is provided on the second high voltage side lead wire L2a. The second internal relay switch 35b is provided on the auxiliary machine parallel lead wire L2p together with the resistance element 35c. The resistance element 35c is provided after the second internal relay switch 35b.

The auxiliary machine smoothing capacitor 36 is connected to the auxiliary machine parallel lead wire L2p and the second low voltage side lead wire L2b. The auxiliary smoothing capacitor 36 alleviates abrupt voltage fluctuations in the power supply unit 31. The auxiliary machine inverter 37 is connected to the second high voltage side lead wire L2a and the second low voltage side lead wire L2b in the subsequent stage of the internal relay 35. The auxiliary machine inverter 37 converts direct current into alternating current and outputs it to the drive unit 32.

In addition to the above-mentioned secondary battery 10 and inverter 22, the power system 100 has a secondary battery relay 40, a secondary battery side converter 51, and a secondary battery as components connected to the first DC lead wire L1. A smoothing capacitor 52 for use and a smoothing capacitor 53 on the motor side are provided. In the present embodiment, the system including the secondary battery side converter 51, the secondary battery smoothing capacitor 52, and the motor side smoothing capacitor 53 is also referred to as a boosting system 50. Further, a system including a drive motor 21, an inverter 22, and a boosting system 50 is also referred to as a drive system 20.

The secondary battery relay 40 is provided on the first DC lead wire L1 that connects the drive motor 21 and the secondary battery 10, and more specifically, on the first DC lead wire L1 between the drive motor 21 and the boosting system 50. The electric contact between the secondary battery 10 and the drive motor 21 and the cooling device 30 is opened and closed. The secondary battery relay 40 includes three relay switches 41, 42, 43, which are switching elements that open and close individually, a relay resistance element 44, and a parallel lead wire L1p connected in parallel to the first low-voltage side lead wire L1b. And have. The first relay switch 41 is provided on the first high voltage side lead wire L1a. The second relay switch 42 is provided on the parallel lead wire L1p. The third relay switch 43 is provided on the first low voltage side lead wire L1b. The relay resistance element 44 is provided on the parallel lead wire L1p together with the second relay switch 42. The relay resistance element 44 is provided after the second relay switch 42 when viewed from the secondary battery 10 side.

The secondary battery side converter 51 is provided between the secondary battery relay 40 and the inverter 22. The secondary battery side converter 51 is a step-up DC / DC converter, and controls charging / discharging of the secondary battery 10. The secondary battery side converter 51 boosts the voltage output from the secondary battery 10 and outputs it to the inverter 22 side. Further, the secondary battery side converter 51 stores the regenerative power generated in the drive motor 21 and converted to direct current by the inverter 22 and the power generated by the fuel cell 71 in the secondary battery 10.

The smoothing capacitor 52 for a secondary battery is connected to the first high-voltage side lead wire L1a and the first low-voltage side lead wire L1b between the secondary battery relay 40 and the secondary battery side converter 51. The smoothing capacitor 52 for a secondary battery alleviates abrupt fluctuations in voltage in the section between the secondary battery 10 and the converter 51 on the secondary battery side.

The motor-side smoothing capacitor 53 is connected to the first high-voltage side lead wire L1a and the first low-voltage side lead wire L1b between the secondary battery-side converter 51 and the inverter 22. The motor-side smoothing capacitor 53 alleviates abrupt fluctuations in voltage in the section between the secondary battery-side converter 51 and the inverter 22. The motor-side smoothing capacitor 53 may be omitted.

The electric power system 100 further includes a cooling device relay 60 provided on the second DC lead wire L2 to open and close the electrical contact between the secondary battery 10 and the cooling device 30. The cooling device relay 60 includes a high-voltage side relay switch 61 provided on the second high-voltage side lead wire L2a and a low-voltage side relay switch 62 provided on the second low-voltage side lead wire L2b.

As described above, the fuel cell system 70 includes a fuel cell 71 that functions as a power source together with the secondary battery 10, and includes a fuel cell side converter 75 for controlling the output power of the fuel cell 71. The fuel cell 71 is a power generation device that generates electricity by receiving the supply of reaction gas from a reaction gas supply unit (not shown) mounted on the vehicle 101. In the present embodiment, the fuel cell 71 is a polymer electrolyte fuel cell. The fuel cell 71 is not limited to the polymer electrolyte fuel cell, and various types of fuel cells such as a solid oxide fuel cell can be adopted.

The fuel cell 71 is connected to the first DC conductor L1 via the third DC conductor L3 between the motor-side smoothing capacitor 53 and the inverter 22. The third DC lead wire L3 includes a third high voltage side lead wire L3a connected to the first high voltage side lead wire L1a and a third low voltage side lead wire L3b connected to the first low voltage side lead wire L1b.

The fuel cell side converter 75 is provided on the third DC lead wire L3. The fuel cell side converter 75 is a step-up DC / DC converter that boosts the output voltage of the fuel cell 71. The output current of the fuel cell 71 is controlled by the fuel cell side converter 75.

In the power system 100, the output power of at least one of the secondary battery 10 and the fuel cell 71 is supplied to the drive motor 21 by the cooperation of the secondary battery side converter 51 and the fuel cell side converter 75. The power generation auxiliary equipment (not shown) used for operating the fuel cell 71, such as the air compressor included in the reaction gas supply unit described above, also has the output of the secondary battery 10 as in the drive motor 21. It is driven using at least one of the electric power and the output electric power of the fuel cell 71.

The electric power system 100 further includes a control unit 80 that controls the electric power system 100. The control unit 80 is composed of an ECU (Electronic Control Unit) including at least one processor and a main storage device. The control unit 80 exerts various functions for controlling the power system 100 as described below by executing a program or instruction read by the processor on the main storage device. At least a part of the functions of the control unit 80 may be configured by a hardware circuit.

The control unit 80 controls the opening / closing operation of the secondary battery relay 40. Further, the control unit 80 detects a failure of the drive system 20, the secondary battery 10, and the fuel cell system 70. In the power source setting process described later, the control unit 80 sets the power source to the cooling device 30 by controlling the opening / closing operation of the secondary battery relay 40 according to the failure detection result.

The control unit 80 manages the drive of the cooling device 30. Further, the control unit 80 controls the drive of the drive motor 21 in response to an output request internally generated by the driver's driving operation or automatic control. Specifically, the control unit 80 controls the voltage input to the inverter 22 by the secondary battery side converter 51, and controls the output current of the fuel cell 71 by the fuel cell side converter 75. Further, the control unit 80 controls the frequency and voltage of the three-phase alternating current supplied to the drive motor 21 by the inverter 22, and controls the rotation speed and the output torque of the drive motor 21. In addition, the control unit 80 controls the power generation state of the fuel cell 71 by controlling the supply of the reaction gas to the fuel cell 71 by the reaction gas supply unit (not shown).

FIG. 2 is a flowchart showing an example of the procedure of the power source setting process. The power source setting process is a process of setting the power source of the cooling device 30. This process is a process that is repeated during the operation of the power system 100.

First, the control unit 80 determines in step S100 whether or not a failure of the fuel cell system 70 has been detected. The control unit 80 detects that the fuel cell system 70 has failed, for example, when the voltage of the fuel cell 71 falls below a predetermined first lower limit voltage. When a failure of the fuel cell system 70 is detected, the control unit 80 proceeds to the process of step S130, sets the power source of the cooling device 30 to the secondary battery 10, and ends the power source setting process. More specifically, the control unit 80 controls the secondary battery relay 40 to be closed and connected so that power is supplied from the secondary battery 10 to the cooling device 30. On the other hand, if the failure of the fuel cell system 70 is not detected, the control unit 80 proceeds to the process of step S110.

The control unit 80 determines in step S110 whether or not a failure of the drive system 20 has been detected. The control unit 80 detects that the drive system 20 has failed, for example, when a current equal to or higher than a predetermined threshold value flows through the inverter 22, that is, when an overcurrent flows through the inverter 22. When a failure of the drive system 20 is detected, the control unit 80 proceeds to the process of step S135, sets the power source of the cooling device 30 to the fuel cell 71, and ends the power source setting process. More specifically, the control unit 80 powers the fuel cell system 70 to the cooling device 30 in a state in which the secondary battery relay 40 is opened and disconnected, that is, a state in which the power supply from the secondary battery 10 is cut off. Is controlled to be supplied. On the other hand, if the failure of the drive system 20 is not detected, the control unit 80 proceeds to the process of step S120.

The control unit 80 determines in step S120 whether or not a failure of the secondary battery 10 has been detected. The control unit 80 detects that the secondary battery 10 has failed, for example, when the voltage of the secondary battery 10 falls below a predetermined second lower limit voltage. When a failure of the secondary battery 10 is detected, the control unit 80 proceeds to the process of step S135, sets the power source of the cooling device 30 to the fuel cell 71, and ends the power source setting process. On the other hand, when the failure of the secondary battery 10 is not detected, the control unit 80 ends the power source setting process without changing the power source.

The steps S100, S110, and S120 are not limited to this order, and may be performed in any order. Further, step S110 and step S120 may be performed in parallel. That is, the control unit 80 determines whether or not a failure of at least one of the drive system 20 and the secondary battery 10 has been detected, and if a failure is detected, proceeds to step S135, and no failure is detected. If so, the power source setting process is terminated without changing the power source.

According to the power system 100 of the present embodiment described above, when the control unit 80 detects a failure of the fuel cell system 70, the control unit 80 closes the secondary battery relay 40 and moves from the secondary battery 10 to the cooling device 30. When power is supplied and at least one of the failure of the secondary battery 10 and the drive system 20 is detected, the fuel cell system 70 supplies power to the cooling device 30, so that the cooling device 30 can be reliably operated. Therefore, even if a part of the electric power system 100 fails, the cooling device 30 can be operated, so that the temperature inside the cooling cabinet 102 can be prevented from rising unintentionally, and the temperature inside the cooling cabinet 102 can be controlled. It can be carried out.

B. Second embodiment:
FIG. 3 is a flowchart showing an example of the procedure of the power source setting process in the second embodiment. This flowchart is different from the first embodiment in that step S125 is provided after step S120, and other steps are the same as those in the first embodiment. Since the configuration of the fuel cell system in the second embodiment is the same as the configuration of the fuel cell system in the first embodiment, the description of the configuration of the fuel cell system will be omitted.

In the second embodiment, when the secondary battery 10 fails in step S120, the control unit 80 proceeds to the process of step S125 and determines whether or not the fuel cell system 70 is activated. When the fuel cell system 70 is activated, the control unit 80 proceeds to the process of step S135. On the other hand, when the fuel cell system 70 is not started, the control unit 80 proceeds to the process of step S137.

In step S137, the control unit 80 stops the power supply and ends the power source setting process. More specifically, the control unit 80 is in a state where the secondary battery relay 40 is opened and disconnected, that is, a state in which the power supply from the secondary battery 10 is cut off, and the fuel cell system 70 is also transferred to the cooling device 30. Control so that power is not supplied.

According to the electric power system 100 of the present embodiment described above, the control unit 80 stops the supply of electric power when the secondary battery 10 is out of order and the fuel cell system 70 is not started. Therefore, for example, when the secondary battery 10 is used as the power source when starting the fuel cell system 70, the fuel cell system 70 uses the failed secondary battery 10 in order to supply electric power to the cooling device 30. Can be avoided.

C. Other Embodiment (C1) In the above embodiment, when the drive system 20 is out of order, the control unit 80 opens and disconnects the secondary battery relay 40, that is, supplies power from the secondary battery 10. The power source is set to the fuel cell 71 in the shut-off state (see step S135 in FIG. 2). Instead, when the drive system 20 is out of order, the control unit 80 closes and connects the secondary battery relay 40, that is, the secondary battery 10 supplies power to the cooling device 30. , The power source may be set to the fuel cell 71 and the secondary battery 10.

(C2) In the above embodiment, the control unit 80 is mounted on the cooling device 30 or the vehicle 101 and is driven by consuming the electric power of the secondary battery 10 or the fuel cell 71 after the power source setting process is completed. The available time may be displayed according to the combination of use of auxiliary equipment such as a power supply device (AC100V power supply) and the like.

FIG. 4 is an example of displaying the available time. FIG. 4 is displayed on, for example, a display (not shown) mounted on the vehicle 101. In FIG. 4, “ON” means to continue using the auxiliary machine. “OFF” means to stop using the auxiliary machine. The passenger of the vehicle 101 can determine which auxiliary machine is prioritized to continue using by looking at this display.

The present disclosure is not limited to the above-described embodiment, and can be realized by various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the column of the outline of the invention are for solving the above-mentioned problems or for achieving a part or all of the above-mentioned effects. In addition, it is possible to replace or combine them as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be appropriately deleted.

10 ... Secondary battery, 20 ... Drive system, 21 ... Drive motor, 22 ... Inverter, 30 ... Cooling device, 31 ... Power supply unit, 32 ... Drive unit, 33 ... Diode, 35 ... Internal relay, 35a ... First internal relay Switch, 35b ... 2nd internal relay switch, 35c ... Resistance element, 36 ... Auxiliary smoothing capacitor, 37 ... Auxiliary inverter, 40 ... Secondary battery relay, 41 ... 1st relay switch, 42 ... 2nd relay Switch, 43 ... 3rd relay switch, 44 ... Relay resistance element, 50 ... Boost system, 51 ... Secondary battery side converter, 52 ... Secondary battery smoothing capacitor, 53 ... Motor side smoothing capacitor, 60 ... Cooling device relay , 61 ... high voltage side relay switch, 62 ... low voltage side relay switch, 70 ... fuel cell system, 71 ... fuel cell, 75 ... fuel cell side converter, 80 ... control unit, 100 ... power system, 101 ... vehicle, 102 ... cooling Storage, DW ... Drive wheel, L1 ... 1st DC lead wire, L1a ... 1st high voltage side lead wire, L1b ... 1st low voltage side lead wire, L1p ... Parallel lead wire, L2 ... 2nd DC lead wire, L2a ... 2nd high voltage side lead wire, L2b ... 2nd low voltage side lead wire, L2p ... Auxiliary parallel lead wire, L3 ... 3rd DC lead wire, L3a ... 3rd high voltage side lead wire, L3b ... 3rd low voltage side lead wire

Claims (1)

An electric power system installed in a fuel cell vehicle equipped with a cooler.
A drive system with a drive motor that generates driving force,
A fuel cell system having a fuel cell capable of supplying electric power to the drive motor and the cooling device for the cooler.
A secondary battery capable of supplying electric power to the drive motor and the cooling device,
A secondary battery relay provided on the first DC lead wire connecting the drive motor and the secondary battery to open and close the electrical contact between the drive motor and the secondary battery.
It is provided with a control unit that detects a failure of the fuel cell system, the drive system, and the secondary battery, and controls opening and closing of the secondary battery relay according to the detection result of the failure.
The control unit
When a failure of the fuel cell system is detected, the relay for the secondary battery is closed, and power is supplied from the secondary battery to the cooling device.
An electric power system that supplies electric power from the fuel cell system to the cooling device when at least one failure of the secondary battery and the drive system is detected.

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