JP2016144366A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable retreat travel by sufficient power even when a power generation device fails in either one of driving systems in an electric vehicle including at least two independent driving systems each of which includes the power generation device, a secondary battery, and a motor.SOLUTION: When brake force is required for a vehicle when one power generation device (fuel battery) of two driving systems fails, a target SOC of a battery of a failure side driving system (failure side battery) is set to be higher than that during a normal time, and regeneration control of each motor in the two driving systems is performed so that a power storage ratio SOC of the failure side battery approximates the target SOC. As a result, amount of charge of the failure side battery can be increased. Accordingly, when driving force is required for the vehicle, sufficient power can be output from the failure side driving system using power of the failure side battery in addition to power from a normal side driving system.SELECTED DRAWING: Figure 2

Description

  The present invention provides a power generation device, a secondary battery that can be charged by power generated by the power generation device, and power required for traveling using power from the secondary battery or power generated by the power generation device. The present invention relates to an electric vehicle in which at least two drive systems including an electric motor capable of output are provided independently.

  Conventionally, as this type of electric vehicle, a vehicle having a drive system including a fuel cell, a battery that can be charged with electric power generated by the fuel cell, and an AC motor that can output driving power has been proposed. (For example, refer to Patent Document 1). In this electric vehicle, when the driving of the vehicle is requested, the AC motor is driven and controlled using the power generated by the fuel cell or the power from the battery, and when the vehicle is requested to be braked, the battery is charged by the regenerative power. The AC motor is regeneratively controlled.

JP 2011-15580 A

  By the way, in a large vehicle such as a bus or a truck, the driving force required for traveling is large, so that the driving system may be enlarged or a plurality of driving systems may be mounted. In the former case, if a failure occurs in the fuel cell of the drive system, the fuel cell cannot generate power, and therefore, the vehicle can only be evacuated within the remaining battery capacity. On the other hand, in the latter case, even when a fuel cell failure occurs in one of the plurality of drive systems, it is possible to perform a retreat travel using a normal drive system. However, even in this case, when the remaining capacity of the battery of the drive system in which the fuel cell has failed is reduced, power can be output only from the normal drive system, and standby running with sufficient power cannot be performed. There is.

  The automobile of the present invention has at least two drive systems independently provided with a power generation device, a secondary battery, and a motor, and is sufficient even when a failure of the power generation device occurs in any of the drive systems. The main purpose is to make it possible to run away by power.

  The electric vehicle of the present invention employs the following means in order to achieve the main object described above.

The electric vehicle of the present invention is
A power generation device, a rechargeable battery that can be charged with power generated by the power generation device, and power generation that outputs power necessary for traveling using the power from the secondary battery or the power generated by the power generation device An electric vehicle provided with at least two drive systems independently equipped with an electric motor,
When the power generation device has failed in one of the at least two drive systems, and when braking of the vehicle is requested, when the storage ratio of the secondary battery of the drive system in which the power generation device has failed is normal The gist is to perform regenerative control of each electric motor of the at least two drive systems so as to approach a higher target power storage ratio.

  In the electric vehicle according to the present invention, the power generation device, the secondary battery that can be charged by the power generated by the power generation device, and the power required for traveling using the power from the secondary battery or the power generated by the power generation device. And at least two drive systems each including a motor capable of generating electric power. In addition, when the power generation device has failed in any one of at least two drive systems, and when braking of the vehicle is requested, the secondary battery of the drive system (failure side drive system) in which the power generation device has failed Each of the electric motors of the at least two drive systems is regeneratively controlled so that the power storage ratio approaches a target power storage ratio that is higher than normal. As described above, when the power generation device has failed in any one of the at least two drive systems, the secondary battery of the failure side drive system is preferentially charged during regenerative braking. As a result, it is possible to prevent the power storage ratio of the secondary battery of the failure-side drive system from being reduced and power cannot be output, so that even if a failure of the power generation device occurs in any of the drive systems, the power generation device In addition to the power from the drive system in which no failure has occurred (normal side drive system), sufficient power can be output from the failure side drive system to perform the retreat travel. As a result, it is possible to further improve the performance during the retreat traveling. If priority is given to the charging of the secondary battery of the failure side drive system during regenerative braking, the amount of charge of the secondary battery of the normal side drive system will decrease, but in the normal side drive system, the secondary power is generated by the power generated by the power generator. It is possible to charge the battery. Here, the “storage ratio” means the ratio of the capacity that can be discharged from the secondary battery to the total capacity. The “power generation device” can be exemplified by a fuel cell. In addition, each electric motor of at least two drive systems may output power to the same drive wheel, or may output power to different drive wheels.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 as one Example of this invention. 5 is a flowchart showing an example of an FC failure regenerative control routine executed by a main ECU 70. It is explanatory drawing which shows an example of target SOC of the battery at the time of normal, and target SOC of the battery at the time of failure. It is explanatory drawing which shows an example of the map for a distribution ratio setting. It is a block diagram which shows the outline of a structure of the electric vehicle 20B of a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  Next, embodiments of the present invention will be described using examples. FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 according to an embodiment of the present invention. The electric vehicle 20 of the embodiment includes a first drive system 30, a second drive system 40, and a main electronic control unit (hereinafter referred to as a main ECU) 60 that controls the entire vehicle, as shown in the figure.

  The first drive system 30 and the second drive system 40 are configured as independent systems, and motors 32 and 42 that output power to the drive shaft 22 connected to the drive wheels 26a and 26b via the differential gear 24. And batteries 34 and 44 capable of supplying electric power to the motors 32 and 42, and fuel cells 36 and 46 capable of supplying electric power to the motors 32 and 42 and the batteries 34 and 44 via the DC / DC converters 35 and 45, respectively. .

  The motors 32 and 42 are configured as well-known synchronous generator motors that can be driven as electric motors and can also be driven as generators. The motors 32 and 42 are driven by switching the switching elements of the inverters 31 and 41 by the main ECU 60 so that the DC power from the batteries 34 and 44 is converted into three-phase AC power and supplied.

  The batteries 34 and 44 are configured as, for example, lithium ion secondary batteries, and exchange power with the motors 32 and 42 via the inverters 31 and 41. The batteries 34 and 44 are managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 50. The battery ECU 50 is connected to a signal necessary for managing the batteries 34, 44, for example, a voltage between terminals from a voltage sensor (not shown) installed between the terminals of the batteries 34, 44, and an output terminal of the batteries 34, 44. The charging / discharging current from the current sensor (not shown) attached to the power line, the battery temperature from the temperature sensor (not shown) attached to the batteries 34 and 44, and the like are input. Data on the state is output to the main ECU 60 by communication. In battery ECU 50, in order to manage batteries 34, 44, the ratio of the capacity of the electric power that can be discharged from batteries 34, 44 at that time based on the integrated value of the charge / discharge current detected by the current sensor to the total capacity. Is also calculated.

  The fuel cells 36 and 46 are configured as, for example, solid polymer fuel cells, and are operated by a fuel cell electronic control unit (hereinafter referred to as FCECU) 52, for example, supply amount or cooling of hydrogen-containing gas or oxygen-containing gas. The amount of water supplied is controlled. The FC ECU 52 is communicably connected to the main ECU 60 and outputs data relating to the state of the fuel cells 36 and 46 to the main ECU 60 as necessary.

  The main ECU 60 is configured as a microprocessor centered on a CPU, and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU, although not shown. The main ECU 60 detects signals necessary for driving and controlling the motors 32 and 42, for example, a signal from a rotational position detection sensor (not shown) that detects the rotational position of the rotor of the motors 32 and 42, and a current sensor (not shown). The phase current applied to the motors 32 and 42, the shift position SP from the shift position sensor 62 that detects the operation position of the shift lever 61, and the accelerator opening from the accelerator pedal position sensor 64 that detects the depression amount of the accelerator pedal 63 Acc, the brake pedal position BP from the brake pedal position sensor 66 for detecting the depression amount of the brake pedal 65, the vehicle speed V from the vehicle speed sensor 68, and the like are input via the input port. From the main ECU 60, switching control signals to the inverters 31 and 41, switching control signals to the DC / DC converters 35 and 45, and the like are output via an output port. Further, as described above, the main ECU 60 is connected to the battery ECU 50 and the FC ECU 52 via the communication port, and exchanges various control signals and data with the battery ECU 50 and the FC ECU 52.

  Next, the operation of the electric vehicle 20 of the embodiment configured as described above will be described. In the electric vehicle 20 according to the embodiment, when the driving force of the vehicle is required, the main ECU 60 requests travel based on the accelerator opening Acc from the accelerator pedal position sensor 64 and the vehicle speed V from the vehicle speed sensor 68. The required travel torque Td * is set. Subsequently, target torques Tm1 * and Tm2 * for each of the motors 32 and 42 are set so that the travel request torque Td * is output from both the motors 32 and 42 at a predetermined distribution ratio. Here, the distribution ratio used for distributing the travel request torque Td * to the motors 32 and 42 can be determined based on, for example, the travel state of the vehicle and the operation of the driver. The distribution ratio may be any ratio as long as the travel request torque Td * is output. Next, the required torque Pm1 * required for the first drive system 30 is set by multiplying the target torque Tm1 * by the number of revolutions of the motor 32 calculated based on the vehicle speed V, and the vehicle speed Vm is set to the target torque Tm2 *. The travel required power Pd2 * required for the second drive system 40 is set by multiplying the rotation number of the motor 42 calculated based on the above. Further, the charging request power Pb1 * required by the battery 34 is set based on the storage ratio SOC of the battery 34 of the first drive system 30 and the battery 44 is set based on the storage ratio SOC of the battery 44 of the second drive system 40. The required charging power Pb2 * is set. Here, the charging request powers Pb1 * and Pb2 * are set such that, for example, when the storage ratio SOC of the batteries 34 and 44 is lower than the target SOC (SOC center), the positive power is set to be higher and the predetermined target SOC is set. If it is higher, a higher negative power is set. Here, the target SOC (SOC center) can be set to 60%, for example. The charging request powers Pb1 * and Pb2 * are powers for charging the batteries 34 and 44 if the powers are positive, and powers for discharging the batteries 34 and 44 if the powers are negative. The target output Pf1 * of the fuel cell 36 of the first drive system 30 is set based on the sum of the travel request power Pd1 * and the charge request power Pb1 *, and the travel request power Pd2 * and the charge request power Pb2 * Is set to the target output Pf2 * of the fuel cell 46 of the second drive system 40. Thus, when the target torques Tm1 * and Tm2 * of the motors 32 and 42 and the target outputs Pf1 * and Pf2 * of the fuel cells 36 and 46 are set, the fuel cell 36 outputs power corresponding to the target outputs Pf1 * and Pf2 *. 46 and the inverters 31 and 41 are controlled so that torques corresponding to the set target torques Tm1 * and Tm2 * are output from the motors 32 and 42, respectively. Thus, while charging and discharging the batteries 34 and 44 with the charge / discharge required powers Pb1 * and Pb2, the motors 32 and 42 can travel by outputting torques corresponding to the target torques Tm1 * and Tm2 *, respectively.

  In the electric vehicle 20 according to the embodiment, when the vehicle is required to have a braking force, the entire motor 32, 42 is to be regenerated based on the brake pedal position and the vehicle speed V from the brake pedal position sensor 66. The required torque Td * is set. Subsequently, target torques Tm1 * and Tm2 * (regenerative torque) for each of the motors 32 and 42 are set so that the regenerative request torque Td * is output from the motors 32 and 42 at a predetermined distribution ratio. Here, the distribution ratio at the time of regeneration is, for example, an even distribution of 50:50, or a higher ratio than a larger one with a smaller storage ratio SOC so that the storage ratio SOC of both batteries 34 and 44 approaches the same level. It can be done. Then, the inverters 31 and 41 are driven and controlled so that the motors 32 and 42 output the regenerative torque corresponding to the set target torques Tm1 * and Tm2 *. Thereby, the braking force is output to the vehicle by the regenerative braking of the motors 32 and 42, and the batteries 34 and 44 can be charged by the electric power generated by the motors 32 and 42 by the regenerative braking.

  Next, an operation when a failure (fail) occurs in one of the fuel cells 36 and 46 in the electric vehicle 20 of the embodiment will be described. The failure determination of the fuel cells 36 and 46 can be performed, for example, by monitoring the state of the fuel cells 36 and 46 such as a voltage drop between cells constituting the fuel cells 36 and 46 by the FC ECU 52.

  When the fuel cell fails in one of the two drive systems 30 and 40, when the vehicle is required to have a driving force, the power of the battery of the fail side drive system (fail side battery) and the normal side drive system The motors 32 and 42 and the normal fuel cell are controlled so as to travel with the travel request torque Td * using the power of the fuel cell (normal fuel cell) or the battery (normal battery). In this case, the distribution ratio used to distribute the travel request torque Td * to the motors 32 and 42 is based on the storage ratio SOC of the fail-side battery, for example, the smaller the storage ratio SOC of the fail-side battery, The ratio can be determined to be small. Here, the fail side drive system must cover all of the electric power required for driving the motor (fail side motor) by discharging from the battery (fail side battery). For this reason, the storage rate SOC of the fail-side battery tends to be lower than the storage rate SOC of the normal-side battery, and sufficient power may not be output from the fail-side motor due to a decrease in the storage rate SOC of the fail-side battery.

  Further, when one of the fuel cells 36 and 46 has failed (failed), and the braking force is required for the vehicle, the FC fail time regeneration control routine illustrated in FIG. 2 is executed.

  When the FC failure regenerative control routine is executed, the CPU 52 of the main ECU 60 first sets the regenerative request torque Td * based on the brake pedal position BP and the vehicle speed V (step S100). Subsequently, the target SOC (SOC center) of the fail-side battery is set to a fail value that is higher than normal (step S110). FIG. 3 is an explanatory diagram showing an example of the target SOC of the battery at the normal time and the target SOC of the battery at the time of failure. In this embodiment, as shown in FIG. 3, the target SOC is set to a first value (for example, 60%) when the fuel cell is normal, and when the fuel cell fails, the target SOC is set to a second value higher than the first value. Value (for example, 80%). Then, based on the set target SOC and the storage rate SOC of the fail side battery, a distribution ratio α of the regeneration required torque Td * to the fail side motor is set (step S120). The processing in step S120 is performed when the relationship between the storage ratio SOC of the fail-side battery and the distribution ratio α is obtained in advance and stored in the ROM as a distribution ratio setting map, and given the storage ratio SOC of the fail-side battery. The distribution ratio α to be calculated is derived from the distribution ratio setting map. An example of the distribution ratio setting map is shown in FIG. The distribution ratio setting map of FIG. 4 is optimized when the target SOC is set to a value for failure (80%). As shown in FIG. 4, the distribution ratio α is set to gradually (linearly) increase as the storage ratio SOC decreases so that the storage ratio SOC of the fail-side battery approaches the target SOC.

  When the distribution ratio α is set, the target torque Tma * of the fail side motor is set by multiplying the regenerative request torque Td * by the set distribution ratio α (step S130). Further, the target torque Tmb * of the normal side motor is set by subtracting the target torque Tma * of the fail side motor from the regeneration required torque Td * (step S140). When the target torques Tma * and Tmb * are set, the inverters 31 and 41 are driven and controlled so that the regenerative torque corresponding to the set target torques Tma * and Tmb * is output from the motors 32 and 42 (step S150). End the hour regeneration control routine.

  According to the electric vehicle 20 of the above-described embodiment, when one of the first drive system 30 and the second drive system 40 fails, when the braking force is required for the vehicle, the fail-side drive is performed. The target SOC of the system battery (fail side battery) is set higher than normal, and the motors 32 and 42 are regeneratively controlled so that the storage rate SOC of the fail side battery approaches the set target SOC. As a result, the amount of charge of the fail-side battery can be increased. Next, when the driving force is required for the vehicle, the power of the fail-side battery is used in addition to the power from the normal driving system. Sufficient power can be output from the fail side drive system. As a result, it is possible to further improve the performance during the retreat traveling. Here, when the regenerative braking of the vehicle is performed, if the charge amount of the fail side battery is increased, the charge amount of the normal side battery is reduced, but by charging the normal side battery using the power of the normal side fuel cell, Thus, the storage rate SOC of the normal battery can be brought close to the target SOC.

  In the electric vehicle 20 of the embodiment, as shown in FIG. 4, the torque distribution ratio α of the fail-side motor is set to change linearly with respect to the change in the power storage ratio SOC. Instead, the distribution ratio α may be changed stepwise with respect to the change in the power storage ratio SOC, or a different distribution ratio α is set depending on whether the power storage ratio SOC is greater than or equal to a predetermined ratio. You may make it (binary control).

  In the electric vehicle 20 according to the embodiment, power is output from the two drive systems 30 and 40 to the same drive wheel. However, power may be output to different drive wheels. For example, as shown in the electric vehicle 20B of the modified example illustrated in FIG. 5, the rotation shaft of the motor 32 of the first drive system 30B is connected to the drive shaft 22 connected to the drive wheels (for example, front wheels) 26a and 26b, The rotation shaft of the motor 42 of the second drive system 40B may be configured to be connected to the drive shaft 122 connected to the drive wheels (for example, rear wheels) 126a and 126b. In addition, the electric vehicle 20 of the embodiment is configured to include the two drive systems 30 and 40, but may be configured to include three or more drive systems.

  The electric vehicle 20 of the embodiment is configured to include the motors 32 and 42, the batteries 34 and 44, and the fuel cells 36 and 46 as the drive system (the first drive system 30 and the second drive system 40). Any type of power generator may be used as long as it is a power generator capable of supplying electric power to a motor or a battery, such as a generator that generates power using power from an internal combustion engine instead of 36 and 46.

  The embodiments of the present invention have been described using the embodiments. However, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course you get.

  The present invention can be used in the manufacturing industry of electric vehicles.

  20, 20B Electric vehicle, 22, 122 Drive shaft, 24 Differential gear, 26a, 26b, 126a, 126b Drive wheel, 30, 30B First drive system, 31 Inverter, 32 Motor, 34 Battery, 35 DC / DC converter, 36 Fuel cell, 40, 40B second drive system, 41 inverter, 42 motor, 44 battery, 45 DC / DC converter, 46 fuel cell, 50 battery ECU, 52 FC ECU, 60 main ECU, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 brake pedal position sensor, 68 vehicle speed sensor.

Claims (1)

A power generation device, a rechargeable battery that can be charged with power generated by the power generation device, and power generation that outputs power necessary for traveling using the power from the secondary battery or the power generated by the power generation device An electric vehicle provided with at least two drive systems independently equipped with an electric motor,
When the power generation device has failed in any of the at least two drive systems, and when braking of the vehicle is requested, the storage ratio of the secondary battery of the drive system in which the power generation device has failed is normal. A regenerative control of each electric motor of the at least two drive systems so as to approach a higher target power storage ratio.

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