JP2019170022A - vehicle - Google Patents

Abstract

To provide an art capable of reducing possibility that a power storage amount of a secondary battery reaches to a prescribed lower limit value.SOLUTION: A vehicle includes: a power consumption source; a fuel battery; a secondary battery, and a control part. The control part decides a power generation amount of the fuel battery using a requested power amount of the power consumption source and a power storage amount of the secondary battery when load limitation on the fuel battery is not performed, and decides the smaller one of (i) the generated power amount capable of being generated by the fuel battery during an output limitation time and (ii) the sum of the request charged power of the secondary battery calculated from the charged power of the secondary battery and the requested power amount of the power consumption source, as the power generation amount of the fuel battery when the load limitation on the fuel battery is performed.SELECTED DRAWING: Figure 6

Description

  The present disclosure relates to a technology of a vehicle including a fuel cell and a secondary battery.

  Conventionally, a fuel cell vehicle having a fuel cell and a secondary battery is known (Patent Document 1). In the conventional technology, the regenerative power generated by the motor is estimated, the amount of increase in the amount of electricity stored when the estimated regenerative power is supplied to the secondary battery is predicted, and the total amount of the current amount of electricity stored and the amount of increase predicted. Charging / discharging of the secondary battery is controlled based on the virtual power storage amount.

Japanese Patent Laid-Open No. 2006-092987

  In the conventional technology, when the output of the fuel cell is limited when the regenerative power is low, for example, when the vehicle is decelerated less frequently, the discharge amount of the secondary battery increases and the storage amount of the secondary battery increases in advance. There may be a risk of reaching a set lower limit. When the storage amount of the secondary battery reaches the lower limit value, the secondary battery cannot be discharged and the motor or the like needs to be driven only by the electric power from the fuel cell. As a result, the running performance of the vehicle may be degraded. Therefore, a technique that can reduce the possibility that the amount of electricity stored in the secondary battery reaches a predetermined lower limit is desired.

  This indication is made in order to solve the above-mentioned subject, and can be realized as the following forms.

  According to one form of the present disclosure, a vehicle is provided. The vehicle includes an electric power consumption source including a motor capable of regenerative operation, a fuel cell capable of supplying electric power to the electric power consumption source, an electric parallel connection with the fuel cell, and supplies electric power to the electric power consumption source. A secondary battery capable of charging the regenerative power generated by the regenerative operation and the generated power of the fuel cell, and a control unit for controlling the power generation amount of the fuel cell, When the output of the fuel cell is not limited, the control unit determines the power generation amount of the fuel cell using the required power amount of the power consumption source and the storage amount of the secondary battery, When the output restriction of the fuel cell is performed, (i) the amount of power that can be generated by the fuel cell at the time of the output restriction, and (ii) the second amount calculated from the storage amount of the secondary battery. The required charge of the secondary battery and the power consumption source Determining the sum of the electric energy, the smaller of the amount of power generated by the fuel cell. According to this aspect, even when the output restriction of the fuel cell is performed, the secondary battery can be charged with at least a part of the generated power of the fuel cell. Thereby, since possibility that the electrical storage amount of a secondary battery will fall can be reduced, possibility that the driving performance of a vehicle will fall can be reduced.

  This indication is realizable in various forms other than the above, for example, can be realized in forms, such as a control method of vehicles.

Schematic which shows the structure of the fuel cell vehicle carrying the fuel cell system in embodiment. The internal block diagram of a control apparatus. The figure for demonstrating a SOC map. The figure for demonstrating an assist rate map. Explanatory drawing which illustrated the relationship between the power generation efficiency and output voltage in a fuel cell. The flowchart of the control which a control part performs. The figure for demonstrating the effect of this embodiment.

A. Embodiment:
FIG. 1 is a schematic diagram illustrating a configuration of a fuel cell vehicle 10 equipped with a fuel cell system 100 according to an embodiment. FIG. 2 is an internal block diagram of the control device 180. The fuel cell vehicle 10 (FIG. 1) includes a fuel cell system 100, an air conditioner 160, and wheels WL. The fuel cell system 100 includes a fuel cell 110, an FC boost converter 120, a power control unit (PCU) 130, a motor driver 132, a motor 136, an air compressor (ACP) 138, a vehicle speed detection unit 139, two Secondary battery 140, SOC detection unit 142, FC auxiliary machine 150, control device 180, and accelerator opening detection unit 190 are provided. The fuel cell vehicle 10 supplies power from the fuel cell 110 and the secondary battery 140 to a power consumption source including the motor 136. Examples of the power consumption source include various devices that can supply power from the fuel cell 110 and the secondary battery 140, and include a motor 136, an ACP 138, an FC auxiliary device 150, and an air conditioner 160.

  The fuel cell 110 is a polymer electrolyte fuel cell that generates power by receiving supply of hydrogen and oxygen as reaction gases. The fuel cell 110 is not limited to a polymer electrolyte fuel cell, and various other types of fuel cells can be employed. The fuel cell 110 is connected to the high-voltage DC wiring DCH via the FC boost converter 120 and connected to the motor driver 132 included in the PCU 130 via the high-voltage DC wiring DCH. The FC boost converter 120 boosts the output voltage VFC of the fuel cell 110 to a high voltage VH that can be used by the motor driver 132. The fuel cell system further includes a mechanism (not shown) for supplying and discharging reaction gas (fuel gas and oxidant gas) to the fuel cell 110, and a cooling circulation system for adjusting the temperature of the fuel cell 110. Have The cooling circulation system includes a refrigerant circulation channel 114 through which a refrigerant for cooling the fuel cell 110 flows, and a temperature sensor 116 provided in an outlet side channel of the fuel cell 110 in the refrigerant circulation channel 114. The detected temperature detected by the temperature sensor 116 is transmitted to the control device 180.

  The motor driver 132 is constituted by a three-phase inverter circuit and is connected to the motor 136. The motor driver 132 converts the output power of the fuel cell 110 supplied via the FC boost converter 120 and the output power of the secondary battery 140 supplied via the DC / DC converter 134 into three-phase AC power. To the motor 136. The motor 136 is configured by a synchronous motor including a three-phase coil, and drives the wheel WL via a gear or the like. The motor 136 can perform a regenerative operation for regenerating the kinetic energy of the fuel cell vehicle 10 when the fuel cell vehicle 10 is braked. The motor 136 also functions as a generator that generates regenerative power by this regenerative operation. The vehicle speed detection unit 139 detects the vehicle speed of the fuel cell vehicle 10 and transmits it to the control device 180.

  The DC / DC converter 134 adjusts the voltage level of the high-voltage DC wiring DCH in accordance with the drive signal from the control device 180, and switches the charging / discharging state of the secondary battery 140. When regenerative power is generated in the motor 136, the regenerative power is converted into DC power by the motor driver 132 and charged to the secondary battery 140 via the DC / DC converter 134. Further, at least a part of the power generated by the fuel cell 110 can be charged in the secondary battery 140.

  The ACP driver 137 is constituted by a three-phase inverter circuit and is connected to the ACP 138. The ACP driver 137 converts the output power of the fuel cell 110 supplied via the FC boost converter 120 and the output power of the secondary battery 140 supplied via the DC / DC converter 134 into three-phase AC power. To ACP138. The ACP 138 is configured by a synchronous motor including a three-phase coil, drives the motor according to the supplied power, and supplies oxygen (air) used for power generation to the fuel cell 110.

  The secondary battery 140 is a power storage device capable of supplying electric power to a power consumption source (for example, the motor 136) by discharging and charging electric power generated by the regenerative operation of the motor 136. It can consist of batteries. The secondary battery 140 is electrically connected in parallel with the fuel cell 110 with respect to the power consumption source. The secondary battery 140 may be another type of battery such as a lead storage battery, a nickel cadmium battery, or a nickel metal hydride battery. The secondary battery 140 is connected to the DC / DC converter 134 included in the PCU 130 via the low-voltage DC wiring DCL, and further connected to the high-voltage DC wiring DCH via the DC / DC converter 134.

  The SOC detection unit 142 detects the storage amount (SOC) of the secondary battery 140 and transmits it to the control device 180. In the present specification, the “power storage amount (SOC)” means the ratio of the remaining charge amount to the current charge capacity of the secondary battery 140. Hereinafter, the storage amount (SOC) of the secondary battery 140 detected by the SOC detection unit 142 is also referred to as “storage amount Rsoc”. The SOC detection unit 142 detects the temperature Tba, the output voltage, and the output current of the secondary battery 140, and detects the storage amount Rsoc based on the detected values. Note that the SOC detection unit 142 of the present embodiment may also transmit the temperature Tba of the secondary battery 140 to the control device 180.

  The FC auxiliary machine 150 and the air conditioner 160 are connected to the low-voltage DC wiring DCL, respectively, and are driven by electric power supplied from the fuel cell 110 and the secondary battery 140. The FC auxiliary machine 150 is an auxiliary machine for power generation of the fuel cell 110 such as a fuel pump that supplies a reaction gas to the fuel cell 110 and a refrigerant pump that supplies a refrigerant to the fuel cell 110. The air conditioner 160 is an air conditioner such as an air conditioner. The accelerator opening detection unit 190 detects the accelerator opening (the amount of depression of the accelerator) of the fuel cell vehicle 10 and transmits the detection result to the control device 180.

  The control device 180 (FIG. 2) is configured by a microcomputer including a control unit 181 and a storage unit 186. The control unit 181 functions as a required power calculation unit 182, an output restriction unit 183, and a power generation amount determination unit 184 by executing various programs included in the storage unit 186. The storage unit 186 includes an SOC map 187 and an assist rate map 188. Further, when detecting various operations such as an accelerator operation by the driver, the control unit 181 controls the power generation of the fuel cell 110 and the charge / discharge of the secondary battery 140 according to the operation content. Further, the control unit 181 generates and transmits a drive signal corresponding to the accelerator opening to the motor driver 132 and the DC / DC converter 134, respectively. The motor driver 132 adjusts the pulse width of the AC voltage in accordance with the drive signal of the control device 180 to cause the motor 136 to rotate according to the accelerator opening.

  The required power calculation unit 182 calculates the required torque from the motor 136 that the fuel cell vehicle 10 has. The required torque is calculated using various information such as the accelerator opening, the current vehicle speed, and the position of the shift lever. Further, the required power calculation unit 182 calculates the required power amount of the power consumption source including the motor 136 using the calculated required torque of the motor 136 and the like. For example, the required power calculation unit 182 may calculate the required power amount of the power consumption source using a map in which the power consumption source is determined according to the accelerator opening, or the driving power required by the power consumption source From the above, the required power amount of the power consumption source may be calculated.

  The output limiting unit 183 determines whether there is an abnormality in the fuel cell system 100, and executes output limitation so that the maximum output of the fuel cell 110 is lower than the maximum rated output when there is no abnormality when there is an abnormality. Specifically, the output limiting unit 183 controls the FC boost converter 120 to limit the output of the fuel cell 110 so that the maximum output of the fuel cell 110 is lower than the maximum rated output of the fuel cell 110. The maximum output of the fuel cell 110 may be limited to a constant value, or may be varied according to the degree and type of abnormality of the fuel cell system 100 (for example, the value of the temperature detected by the temperature sensor 116). For example, the output limiting unit 183 determines whether there is an abnormality in the fuel cell system 100 using the temperature detected by the temperature sensor 116 (FIG. 1). Specifically, the output limiting unit 183 determines that there is an abnormality in the fuel cell system 100 when the temperature detected by the temperature sensor 116 is equal to or higher than a predetermined threshold. Further, for example, the output limiting unit 183 is configured to assume an assumed output of the fuel cell 110 according to the control content of a fuel gas supply system (not shown) that supplies hydrogen to the fuel cell 110 and an actual output of the fuel cell 110. Is determined to be abnormal in the fuel cell 110.

  When the required power calculation unit 182 does not limit the output of the fuel cell 110, the power generation amount determination unit 184 determines the required power amount of the power consumption source calculated by the required power calculation unit 182 and the secondary battery 140. The power generation amount of the fuel cell 110 is determined using the amount of electricity stored. Specifically, the power generation amount determination unit 184 refers to the SOC map 187 and the assist rate map 188 to prioritize the power generation efficiency of the fuel cell 110 and charge / discharge the secondary battery 140. Determine the amount. The power generation efficiency of the fuel cell 110 is a ratio of energy (generated power) generated by the fuel cell 110 to energy consumed by hydrogen.

In addition, when the output of the fuel cell 110 is limited, the power generation amount determination unit 184 determines the power generation amount of the fuel cell 110 as a smaller one of the following two power amounts (i) and (ii). Determine as. The required amount of charge of the secondary battery 140 (ii) below is calculated by the power generation amount determination unit 184 using the SOC map 187.
(I) Amount of power that can be generated by the fuel cell 110 when the output is limited (ii) A required charge amount of the secondary battery 140 calculated from a storage amount Rsoc of the secondary battery 140 and a required power amount of the power consumption source Sum (total power generation)

  FIG. 3 is a diagram for explaining the SOC map 187. FIG. 4 is a diagram for explaining the assist rate map 188. FIG. 5 is an explanatory diagram illustrating the relationship between the power generation efficiency and the output voltage in the fuel cell 110. In FIG. 3, the horizontal axis represents the storage amount (SOC) of the secondary battery 140, and the vertical axis represents the charge / discharge amount of the secondary battery 140. In FIG. 4, the horizontal axis is the amount of electricity stored in the secondary battery 140, and the vertical axis is the assist rate of the secondary battery 140. As the assist rate decreases, the ratio of power supplied from the secondary battery 140 decreases, and the ratio of power supplied from the fuel cell 110 increases.

  The SOC map 187 (FIG. 3) shows the secondary battery 140 in two cases, that is, an FC normal operation in which no output restriction occurs in the fuel cell 110 and an FC output restriction in which the output restriction occurs in the fuel cell 110. This is a map showing the relationship between the amount of stored electricity (SOC) and the amount of charge / discharge of the secondary battery 140.

  Control unit 181 (FIG. 2) controls charging / discharging of secondary battery 140 based on the position of storage amount Rsoc in SOC map 187. During the FC normal operation, the secondary battery 140 is charged and discharged so that the charged amount Rsoc is maintained between the upper limit value Ha and the lower limit value La. In other words, during FC normal operation, when the charged amount Rsoc falls below the lower limit value La, the secondary battery 140 is charged with regenerative power, and when the charged amount is greater than or equal to the lower limit value La, the secondary battery 140 is discharged. This is done to supply power to a power consuming source including the motor 136. The discharge amount (output) of the secondary battery 140 is a target discharge amount of the secondary battery 140 determined by referring to a map (not shown) from the required power of the power consumption source, and an assist rate determined using FIG. It is calculated by the product of

  As shown in FIG. 5, the fuel cell 110 has the highest power generation efficiency when the output voltage V1 has a relatively low load, and the power generation efficiency decreases as the load increases from there. During FC normal operation, the load of the fuel cell 110 is reduced by increasing the assist rate of the secondary battery 140 with respect to the required power of the motor 136, so that the fuel cell 110 can be operated with high efficiency. Thereby, the fuel consumption of the fuel cell 110 can be improved. During FC normal operation, the charge / discharge amount of the secondary battery 140 is determined using the SOC map 187 and the assist rate map 188 so that the power generation efficiency of the fuel cell 110 is improved.

  On the other hand, at the time of FC output restriction (FIG. 3), when the charged amount Rsoc is equal to or smaller than a predetermined threshold value Sa, the secondary battery 140 is charged as follows. The control unit 181 includes the required power amount of the power consumption source, the sum of the required power storage amount of the secondary battery 140 at the time of FC output restriction calculated by referring to the power storage amount Rsoc and the SOC map 187 in FIG. When the total power generation amount) is smaller than the power generation amount that can be generated by the fuel cell 110 (the maximum power generation amount when the FC output is limited), the fuel cell 110 is caused to generate the total power generation amount. Then, the control unit 181 charges the secondary battery 140 by supplying the secondary battery 140 with power obtained by subtracting the required power generation amount of the power consumption source from the total power generation amount.

  FIG. 6 is a flowchart of control executed by the control unit 181. First, this flowchart is repeatedly executed at predetermined time intervals starting from the fact that the start switch for starting the fuel cell vehicle 10 is turned ON.

  First, the required power calculation unit 182 calculates the required torque of the motor 136 using information such as the accelerator opening, the current vehicle speed, and the position of the shift lever received by the control unit 181 (step S12). In step S12, the required driving force of power consumption sources other than the motor 136 is also calculated. Next, the required power calculation unit 182 calculates the required power amount of the power consumption source by, for example, calculating the required power amount of the motor 136 by using the rotation speed of the motor 136 and the calculated required torque (step) S14). The required power calculation unit 182 determines the target discharge amount of the secondary battery 140 using a map (not shown) that defines the relationship between the required power amount of the power consumption source and the target discharge amount of the secondary battery 140.

  Next, the power generation amount determination unit 184 determines whether or not output restriction is performed on the fuel cell 110 by the output restriction unit 183 (step S16). When the output restriction is not performed, the power generation amount determination unit 184 refers to the data during the normal FC operation of the SOC map 187 and the storage amount Rsoc. Then, the power generation amount determination unit 184 calculates charging power supplied to the secondary battery 140 or discharging power supplied from the secondary battery 140 to the power consumption source so that the power generation efficiency of the fuel cell 110 becomes higher (step S18). ). That is, in step S18, the charge / discharge power of the secondary battery 140 is calculated by giving priority to the power generation efficiency of the fuel cell 110 over the charging of the secondary battery 140.

After step S18, the power generation amount determination unit 184 determines the power generation amount of the fuel cell 110 using the required power amount of the power consumption source and the storage amount of the secondary battery 140 (step S20). Specifically, the power generation amount determination unit 184 determines the power generation amount of the fuel cell 110 using the following equation (1). In the following formula (1), “required power amount of power consumption source” is the value calculated in step S14, and “charge / discharge power amount of secondary battery” is the value calculated in step S18. In the following formula (1), “charge / discharge power amount of secondary battery” is treated as a negative value for the discharge power amount and a positive value for the charge power amount.
Fuel cell power generation amount = required power amount of power consumption source + charge / discharge power amount of secondary battery (1)

  After step S20, the control unit 181 calculates the amount of power (permitted power amount) that can be supplied to a power consumption source such as the motor 136 (step S22). In step S22, the permitted power amount is calculated using the actual power generation amount of the fuel cell 110 and the actual discharge power amount (or charge power amount) of the secondary battery 140. After step S22, the control unit 181 controls the driving force of the power consumption source such as the torque of the motor 136 so as to be equal to or less than the calculated permitted power amount (step S24).

  When it is determined in step S16 that the output restriction is performed, the power generation amount determination unit 184 refers to the data at the time of FC output restriction in FIG. 3 and the storage amount Rsoc, and stores the power of the secondary battery 140. Charge power (required charge amount) for recovering the amount is calculated (step S30). That is, in step S30, the recovery of the SOC of the secondary battery 140 is prioritized over the power generation efficiency of the fuel cell 110. In addition, when the charged amount Rsoc exceeds the threshold value Sa shown in FIG. 3, the required charge amount is calculated as zero.

  After step S30, the power generation amount determination unit 184, as described above, (i) the power generation amount that the fuel cell 110 can generate when the output is limited, (ii) the required charge amount of the secondary battery 140, and the power consumption The smaller of the sum (total power generation amount) with the required power amount of the source is determined as the power generation amount of the fuel cell 110 (step S32). After step S32, step S22 and step S24 described above are executed.

  FIG. 7 is a diagram for explaining the effect of the present embodiment. In FIG. 7, the vertical axis represents the amount of power, and the horizontal axis represents the elapsed time. When the required power amount of the power consumption source is positive, power is supplied from the fuel cell 110 or the secondary battery 140 to the power consumption source. When the required power amount is negative, the regenerative power of the motor 136 is supplied to the secondary battery 140. Is done.

  When the output of the fuel cell 110 is limited in a situation where regenerative power is unlikely to occur when the fuel cell vehicle 10 is traveling on an expressway, the amount of power supplied from the secondary battery 140 to the power consumption source May increase. In this case, the storage amount Rsoc of the secondary battery 140 reaches the lower limit value La, and there is a possibility that power cannot be supplied from the secondary battery 140 to the power consumption source. When power cannot be supplied from the secondary battery 140 to the power consumption source, the running performance of the fuel cell vehicle 10 may deteriorate. In this embodiment, when the output limitation of the fuel cell 110 is performed, the power generation amount determination unit 184 determines (i) the power generation amount that can be generated by the fuel cell 110 when the output is limited (the maximum power generation amount when the FC output is limited). ) And (ii) the sum of the required charge amount of the secondary battery 140 and the required power amount of the power consumption source is determined as the power generation amount of the fuel cell 110 (step S32 in FIG. 6). . Thus, when the sum of the required charge amount of the secondary battery 140 and the required power amount of the power consumption source is determined as the power generation amount of the fuel cell 110, at least a part of the generated power of the fuel cell 110 is used as the secondary battery 140. Can be charged. For example, in FIG. 7, the generated power for the area with cross-hatching can be supplied to the secondary battery 140. Thereby, since possibility that the electrical storage amount of the secondary battery 140 will fall can be reduced, possibility that the driving performance of a vehicle will fall can be reduced.

  In addition, this indication is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with a configuration of another modified mode, and the configuration of another modified mode can be added to the configuration of a certain embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. Moreover, you may combine embodiment, a deformation | transformation aspect, and a modification.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell vehicle 100 ... Fuel cell system 110 ... Fuel cell 114 ... Refrigerant circulation flow path 116 ... Temperature sensor 120 ... FC boost converter 132 ... Motor driver 134 ... DC / DC converter 136 ... Motor 137 ... ACP driver 138 ... Air compressor DESCRIPTION OF SYMBOLS 139 ... Vehicle speed detection part 140 ... Secondary battery 142 ... SOC detection part 150 ... FC auxiliary machine 180 ... Control apparatus 181 ... Control part 182 ... Required electric power calculation part 183 ... Output restriction part 184 ... Electric power generation amount determination part 186 ... Memory | storage part 187 ... SOC map 188 ... Assist rate map 190 ... Accelerator opening detector DCH ... High-voltage DC wiring DCL ... Low-voltage DC wiring Rsoc ... Amount of storage V1 ... Output voltage VFC ... Output voltage VH ... High-voltage voltage WL ... Wheel

Claims (1)

A vehicle,
A power consumption source including a motor capable of regenerative operation;
A fuel cell capable of supplying power to the power consumption source;
A secondary battery that is electrically connected to the fuel cell in parallel and supplies power to the power consuming source, and is capable of charging the regenerative power generated by the regenerative operation and the generated power of the fuel cell. When,
A control unit for controlling the power generation amount of the fuel cell,
The controller is
If the output of the fuel cell is not limited, the power generation amount of the fuel cell is determined using the required power amount of the power consumption source and the storage amount of the secondary battery,
When the output restriction of the fuel cell is performed, (i) the amount of power that can be generated by the fuel cell at the time of the output restriction, and (ii) the second amount calculated from the storage amount of the secondary battery. A vehicle in which the smaller one of the sum of the required charge amount of the secondary battery and the required power amount of the power consumption source is determined as the power generation amount of the fuel cell.

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