WO2024195873A1 - Control system, work machine, and control method - Google Patents

Abstract

This control system (163) controls a work machine (10) having a work device as well as being provided with a fuel cell (143) and a power storage device (144). The control system is provided with: a required power determination unit (174) that determines the magnitude of required power necessary for the operation of the work machine; and a fuel cell control unit (178) that controls the fuel cell, on the basis of the standard generation power of the fuel cell, the maximum dischargeable power of the power storage device, and the required power.

Description

CONTROL SYSTEM, WORK MACHINE AND CONTROL METHOD

The present disclosure relates to a control system, a work machine, and a control method.
This application claims priority based on Japanese Patent Application No. 2023-047059, filed in Japan on March 23, 2023, the contents of which are incorporated herein by reference.

Machines equipped with fuel cells that use hydrogen gas as fuel are being considered. Machines powered by fuel cells usually have batteries to limit the amount of fuel cell they carry and to absorb regenerative power when going downhill. For this reason, the machine's control device needs to perform energy management to appropriately distribute the energy between the fuel cell and the battery.

Patent Document 1 discloses a technology that uses an adaptive algorithm to change the output ratio between a fuel cell and a battery in a hybrid system that uses a fuel cell and a battery.

China Patent Publication No. 108556672

A range extender system is known as a method for operating a power supply system equipped with a fuel cell and a power storage device. The range extender system constantly outputs a constant amount of power from the fuel cell, and the difference between the power required to drive a work machine and the power output by the fuel cell is compensated for by charging or discharging the power storage device. However, there is a possibility that the power may be insufficient or excessive, depending on the operating state of the machine and the state of the power storage device.
An object of the present disclosure is to provide a control system, a work machine, and a control method that are capable of appropriately determining the power that should be output by a fuel cell mounted on the work machine.

According to one aspect of the present disclosure, the control system is a control system for controlling a work machine having a fuel cell and a power storage device and having a work implement, and includes a required power determination unit that determines the amount of required power required to operate the work machine, and a fuel cell control unit that controls the fuel cell to output power greater than the standard generated power when the sum of the standard generated power of the fuel cell and the maximum dischargeable power of the power storage device is less than the required power.

According to the above aspect, the control system can appropriately determine the power that should be output by the fuel cell mounted on the work machine.

1 is a perspective view that illustrates a working machine according to a first embodiment. 1 is a schematic block diagram showing the configuration of a power system and a drive system provided in a work machine according to a first embodiment. 2 is a schematic block diagram showing the configuration of a control system provided in the work machine according to the first embodiment. FIG. FIG. 4 is a block diagram showing a calculation algorithm performed by a control amount determiner according to the first embodiment. 3 is a flowchart showing a control method for a work machine according to the first embodiment. FIG. 1 is a schematic block diagram illustrating a configuration of a computer according to at least one embodiment. FIG. 11 is a perspective view of a work machine according to a second embodiment. FIG. 11 is a schematic block diagram showing the configuration of a power system and a drive system provided in a work machine according to a second embodiment.

First Embodiment
System Configuration
Hereinafter, the embodiments will be described in detail with reference to the drawings.
1 is a perspective view that shows a schematic diagram of a work machine 10 according to a first embodiment. The work machine 10 includes a dump body 11, a vehicle body 12, and a traveling device 13.

The dump body 11 is a member on which a load is loaded. At least a portion of the dump body 11 is positioned above the vehicle body 12. The dump body 11 performs a dumping operation and a lowering operation. Through the dumping operation and the lowering operation, the dump body 11 is adjusted to a dumping position and a loaded position. The dump position refers to a position in which the dump body 11 is raised. The loaded position refers to a position in which the dump body 11 is lowered. The dump body 11 is an example of a work machine.

The dump operation refers to an operation in which the dump body 11 is moved away from the vehicle body 12 and tilted in the dumping direction. The dumping direction is toward the rear of the vehicle body 12. In the embodiment, the dump operation includes lifting the front end of the dump body 11 and tilting the dump body 11 rearward. The dump operation causes the loading surface of the dump body 11 to tilt downward toward the rear.

The lowering operation refers to the operation of bringing the dump body 11 closer to the vehicle body 12. In the embodiment, the lowering operation includes lowering the front end of the dump body 11.

When performing soil removal operations, the dump body 11 performs a dumping operation to change from a loaded position to a dumping position. If a load is loaded on the dump body 11, the load is discharged rearward from the rear end of the dump body 11 by the dumping operation. When loading operations are performed, the dump body 11 is adjusted to the loaded position.

The vehicle body 12 includes a vehicle body frame. The vehicle body 12 supports the dump body 11. The vehicle body 12 is supported by the running gear 13.

The traveling device 13 supports the vehicle body 12. The traveling device 13 drives the work machine 10. The traveling device 13 drives the work machine 10 forward or backward. At least a portion of the traveling device 13 is disposed below the vehicle body 12. The traveling device 13 has a pair of front wheels and a pair of rear wheels. The front wheels are steered wheels, and the rear wheels are driven wheels. Note that the combination of steered wheels and driven wheels is not limited to this, and the traveling device 13 may be four-wheel drive or four-wheel steering.

2 is a schematic block diagram showing the configuration of the power system 14 and drive system 15 provided in the work machine 10 according to the first embodiment. The power system 14 includes a hydrogen tank 141, a hydrogen supply device 142, a fuel cell 143, a battery 144, a DCDC converter 145, and a retarder grid 146. The retarder grid 146 is an example of a consumption device that consumes surplus power.
The hydrogen supply device 142 supplies hydrogen gas filled in the hydrogen tank 141 to the fuel cell 143. The fuel cell 143 generates electric power by electrochemically reacting hydrogen supplied from the hydrogen supply device 142 with oxygen contained in the outside air. The battery 144 stores the electric power generated in the fuel cell 143. The battery 144 is an example of an electric power storage device. The battery 144 is provided with a monitoring device (not shown) that monitors the state of the battery 144. Note that in other embodiments, the work machine 10 may be provided with another electric power storage device such as a capacitor instead of the battery 144. The monitoring device determines the maximum chargeable power and the maximum dischargeable power based on various state quantities of the battery 144, such as the temperature, charging rate, and voltage of the battery 144, in order to prevent the battery 144 from failing. For example, the maximum chargeable power and the maximum dischargeable power have smaller values as the temperature of the battery 144 increases. The DCDC converter 145 outputs electric power from the fuel cell 143 or the battery 144 connected thereto in accordance with an instruction from the control system 16 (see FIG. 3). The retarder grid 146 converts regenerative power from the drivetrain 15 into thermal energy when the battery 144 cannot be charged.

The power output by the power system 14 is output to the drive system 15 via the bus B. The drive system 15 has an inverter 151, a pump drive motor 152, a hydraulic pump 153, a hoist cylinder 154, an inverter 155, and a travel drive motor 156. The inverter 151 converts the DC current from the bus B into three-phase AC current and supplies it to the pump drive motor 152. The pump drive motor 152 drives the hydraulic pump 153. The hydraulic oil discharged from the hydraulic pump 153 is supplied to the hoist cylinder 154 via a control valve (not shown). The hoist cylinder 154 is operated by the hydraulic oil being supplied to the hoist cylinder 154. The hoist cylinder 154 performs a dumping operation or a lowering operation of the dump body 11. The inverter 155 converts the DC current from the bus B into three-phase AC current and supplies it to the travel drive motor 156. The rotational force generated by the travel drive motor 156 is transmitted to the drive wheels of the travel device 13. The travel drive motor 156 performs power running to travel the work machine 10, and regenerative running to generate regenerative power to decelerate the work machine 10.

The work machine 10 is equipped with a control system 16 that controls the power system 14 and the drive system 15. FIG. 3 is a schematic block diagram showing the configuration of the control system 16 equipped in the work machine 10 according to the first embodiment. The control system 16 is equipped with a measuring device 161, an operating device 162, and a control device 163.

The measurement device 161 collects data relating to the operating state and traveling state of the work machine 10. The measurement device 161 includes a temperature sensor that measures the temperature of the battery 144, a fuel gauge that measures the charging rate of the battery 144, a current sensor that measures the passing current of the inverter 155, and a voltage sensor that measures the voltage of the bus B.
The operation device 162 is provided in the driver's cab and receives operations by the operator. The operation device 162 includes an accelerator pedal, a brake pedal, a steering wheel, a dump lever, and the like.
The control device 163 drives the work machine 10 in accordance with the amount of operation of the operating device 162 .

The control device 163 includes a data acquisition unit 171, a standard determination unit 172, a vehicle body control unit 173, a required power calculation unit 174, a regenerative power identification unit 175, a battery capacity identification unit 176, a control amount determination unit 177, a fuel cell control unit 178, and a battery control unit 179. The control device 163 is an example of a control system.

The data acquisition unit 171 acquires measurement data from the measuring device 161 .
The standard determination unit 172 determines a standard generated power, which is a standard for the power to be output from the fuel cell 143, based on the measurement data of the charging rate of the battery 144 acquired by the data acquisition unit 171. Specifically, the standard determination unit 172 determines a lower standard generated power value as the charging rate of the battery 144 increases, and determines a higher standard generated power value as the charging rate of the battery 144 decreases. In other words, the standard determination unit 172 determines the standard generated power value using a range extender method. The standard generated power value monotonically decreases (does not monotonically increase) with respect to the charging rate of the battery 144.

The vehicle body control unit 173 generates a control signal for controlling the work machine 10 based on the amount of operation of the operating device 162. For example, the vehicle body control unit 173 generates control signals for controlling the steering, accelerator, brakes, vessel operation, etc. of the traveling device 13.

The required power calculation unit 174 calculates the required power required in the power system 14 based on the control signal generated by the vehicle body control unit 173. The required power calculation unit 174 is an example of a required power determination unit.
The regenerative power identifying unit 175 identifies the regenerative power generated by the work machine 10 based on the measurement data of the voltage of the bus B and the current passing through the inverter 155 acquired by the data acquiring unit 171 .

The battery capacity identification unit 176 identifies the maximum chargeable power and the maximum dischargeable power determined by a monitoring device for the battery 144 based on the measurement data of the state quantity of the battery 144 acquired by the data acquisition unit 171. The battery capacity identification unit 176 may identify the maximum chargeable power and the maximum dischargeable power by inquiring about the maximum chargeable power and the maximum dischargeable power from the monitoring device for the battery 144.

The control amount determination unit 177 determines the power generated by the fuel cell 143 and the charging or discharging power of the battery 144 based on the required power, the regenerative power, the standard power generated by the fuel cell 143, and the maximum chargeable power and maximum dischargeable power of the battery 144. The method of determining the control amount by the control amount determination unit 177 will be described later.

The fuel cell control unit 178 controls the fuel cell 143 to generate power in accordance with the power generation determined by the control amount determination unit 177. In other words, the fuel cell control unit 178 controls the amount of hydrogen supplied by the hydrogen supply device 142 so that the fuel cell 143 outputs the power generation determined by the control amount determination unit 177.
The battery control unit 179 controls the DCDC converter 145 connected to the battery 144 so as to discharge the discharge power determined by the control amount determination unit 177 to the battery 144, or to charge the battery 144 with the charge power determined by the control amount determination unit 177. The battery control unit 179 is an example of a power storage device control unit.

Here, a description will be given of the calculation by the control amount determiner 177 according to the first embodiment. Fig. 4 is a block diagram showing a calculation algorithm by the control amount determiner 177 according to the first embodiment.
The control amount determination unit 177 includes a first subtraction block 181 , a second subtraction block 182 , a MAX block 183 , a first MIN block 184 , a third subtraction block 186 , an addition block 188 , a second MIN block 187 , a third MIN block 189 , and a fourth subtraction block 190 .

The first subtraction block 181 subtracts the maximum dischargeable power from the subtracted required power.
The second subtraction block 182 subtracts the regenerative power from the maximum chargeable power.
4 are represented by the difference between the required power calculated by the required power calculation unit 174 and the regenerative power identified by the regenerative power identification unit 175. Specifically, the required power is the value obtained by subtracting the regenerative power from the required power, and the regenerative power is the value obtained by subtracting the required power from the regenerative power. In other words, the required power is equal to the value obtained by multiplying the regenerative power by -1.

The MAX block 183 determines the larger of the standard generated power and the calculation result of the first subtraction block 181. In other words, if the net required power can be covered within the discharge capacity of the battery 144 when the fuel cell 143 is made to generate the standard generated power, the MAX block 183 outputs the standard generated power. If the net required power cannot be covered within the discharge capacity of the battery 144 when the fuel cell 143 is made to generate the standard generated power, the MAX block 183 outputs the difference between the required power and the maximum dischargeable power of the battery 144.

The first MIN block 184 determines the smaller of the calculation result of the MAX block 183 and the calculation result of the second subtraction block 182. In other words, if the standard generated power can be absorbed within the charging capacity of the battery 144 when the fuel cell 143 is made to generate standard generated power, the first MIN block 184 outputs the standard generated power. If the standard generated power cannot be absorbed within the charging capacity of the battery 144 when the fuel cell 143 is made to generate standard generated power, the first MIN block 184 outputs the difference between the maximum chargeable power of the battery 144 and the regenerative power. However, if the calculation result is a negative number, the first MIN block 184 outputs zero as the calculation result. The calculation result of the first MIN block 184 indicates the total generated power of the fuel cell 143.

A third subtraction block 186 subtracts the result of the calculation by the first MIN block 184 from the required power.
The second MIN block 187 specifies the smaller of the calculation result of the third subtraction block 186 and the maximum dischargeable power as the discharge power of the battery 144. In other words, when the fuel cell 143 generates power at the standard power generation power, the second MIN block 187 determines the difference between the total power generation power of the fuel cell 143 and the net required power as the discharge power. When the fuel cell 143 generates power greater than the standard power generation power, the second MIN block 187 determines the maximum dischargeable power as the discharge power.

The addition block 188 adds the calculation result of the first MIN block 184 and the subtracted regenerative power.
The third MIN block 189 specifies the smaller of the maximum chargeable power or the calculation result of the addition block 188 as the charging power for the battery 144. In other words, when the sum of the total power generated by the fuel cell 143 and the regenerative power balance exceeds the maximum chargeable power, the third MIN block 189 determines the maximum chargeable power as the charging power. When the sum of the total power generated by the fuel cell 143 and the regenerative power balance does not exceed the maximum chargeable power, the third MIN block 189 determines the sum of the total power generated by the fuel cell 143 and the regenerative power balance as the charging power.

The fourth subtraction block 190 identifies the result of subtracting the calculation result of the third MIN block 189 from the calculation result of the addition block 188 as the surplus power to be consumed by the retarder grid 146.

Note that at least one of the discharge power and charge power calculated by the control amount determination unit 177 will always be zero.

FIG. 5 is a flowchart showing a method for controlling the work machine 10 according to the first embodiment. When the work machine 10 according to the first embodiment starts traveling, the data acquisition unit 171 of the control device 163 acquires the measured values of the temperature of the battery 144, the charging rate of the battery 144, the current passing through the inverter 155, and the voltage of the bus bar B from the measuring device 161, and acquires the operation amount from the operation device 162 (step S1).

Next, the standard determination unit 172 determines the standard generated power, which is the standard for the power to be output by the fuel cell 143, based on the measurement data of the charging rate of the battery 144 acquired in step S1 (step S2). The vehicle body control unit 173 generates a control signal for controlling the work machine 10 based on the operation amount acquired in step S1 (step S3).

The required power calculation unit 174 calculates the required power based on the control signal generated in step S3 (step S4). The regenerative power identification unit 175 identifies the regenerative power based on the measurement data of the voltage of the bus B and the current passing through the inverter 155 acquired in step S1 (step S5).

The battery capacity determination unit 176 determines the maximum chargeable power and maximum dischargeable power of the battery 144 based on the measurement data of the state quantity of the battery 144 acquired in step S1 (step S6).

The control quantity determination unit 177 determines the generated power of the fuel cell 143, the charging or discharging power of the battery 144, and the surplus power consumed by the retarder grid 146 based on the standard generated power calculated in step S2, the required power calculated in step S4, the regenerative power calculated in step S5, and the maximum chargeable power and maximum dischargeable power identified in step S6 (step S7).

The fuel cell control unit 178 controls the fuel cell 143 to generate power according to the generated power determined in step S7 (step S8). If the generated power determined in step S7 is zero, the fuel cell control unit 178 may stop the power generation of the fuel cell 143. The battery control unit 179 also controls the DCDC converter 145 according to the discharge power or charge power determined in step S7 (step S9).

<Action and Effects>
In this manner, the control device 163 according to the first embodiment functions as follows. The required power calculation unit 174 determines the magnitude of the required power required for the operation of the work machine 10. When the sum of the standard generated power of the fuel cell 143 and the maximum dischargeable power of the battery 144 is smaller than the required power, the fuel cell control unit 178 controls the fuel cell 143 to output power larger than the standard generated power. Specifically, when the sum of the standard generated power and the maximum dischargeable power is smaller than the required power, the fuel cell control unit 178 controls the fuel cell 143 to output power equal to the difference between the required power and the maximum dischargeable power of the battery 144. In this way, the control device 163 can determine the power that the fuel cell 143 should output so that a power shortage does not occur depending on the working state of the work machine 10 or the state of the battery 144. For example, when the operator accelerates the work machine 10, the work machine 10 may require more required power. Also, for example, when the work machine 10 travels uphill, the work machine 10 may require more required power. Furthermore, for example, a decrease in the charging rate or an increase in temperature of the battery 144 may cause the maximum dischargeable power of the battery 144 to decrease. At this time, if the required power exceeds the sum of the standard generated power of the fuel cell 143 and the maximum dischargeable power of the battery 144, the control device 163 can increase the output of the fuel cell 143. In other words, the control device 163 can appropriately determine the power that should be output by the fuel cell 143 mounted on the work machine 10. Note that in other embodiments, the fuel cell control unit 178 may control the fuel cell 143 to output power that is greater than the difference between the required power and the maximum dischargeable power of the battery 144.

The control device 163 according to the first embodiment functions as follows. The regenerative power identification unit 175 identifies the magnitude of the regenerative power generated by the work machine 10. When the sum of the standard power generation and the regenerative power of the fuel cell 143 is greater than the maximum chargeable power of the battery 144, the fuel cell control unit 178 controls the fuel cell 143 to output power less than the standard power generation or to stop power generation. Specifically, when the sum of the standard power generation and the regenerative power is greater than the maximum chargeable power, the fuel cell control unit 178 controls the fuel cell 143 to output power equal to the difference between the maximum chargeable power and the regenerative power. This allows the control device 163 to determine the power that the fuel cell 143 should output so that regeneration lapse due to the power generated by the fuel cell 143 does not occur. For example, when the operator decelerates the work machine 10, the travel drive motor 156 may generate more regenerative power. Also, for example, when the work machine 10 travels downhill, the work machine 10 may generate more regenerative power. Furthermore, for example, an increase in the charging rate or temperature of the battery 144 may cause the maximum chargeable power of the battery 144 to decrease. In this case, the control device 163 can limit the output of the fuel cell 143 if the sum of the regenerative power and the standard power generation of the fuel cell 143 exceeds the maximum chargeable power of the battery 144. In other words, the control device 163 can appropriately determine the power that should be output by the fuel cell 143 mounted on the work machine 10. Note that in other embodiments, the fuel cell control unit 178 may control the fuel cell 143 to output power that is smaller than the power difference between the maximum dischargeable power of the battery 144 and the regenerative power.

Computer Configuration
FIG. 6 is a schematic block diagram illustrating a computer configuration according to at least one embodiment.
The computer 90 comprises a processor 91 , a main memory 92 , a storage 93 , and an interface 94 .
The above-mentioned control device 163 is implemented in the computer 90. The operations of the above-mentioned processing units are stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it in the main memory 92, and executes the above-mentioned processing in accordance with the program. The processor 91 also secures storage areas in the main memory 92 corresponding to the above-mentioned storage units in accordance with the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

The program may be for implementing part of the functions to be performed by the computer 90. For example, the program may be for implementing the functions by combining with other programs already stored in the storage or with other programs implemented in other devices. In another embodiment, the computer 90 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, part or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also included as an example of a processor. In another embodiment, the computer 90 may be virtualized on one or more computers.

Examples of storage 93 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 94 or a communication line. In addition, when this program is distributed to computer 90 via a communication line, computer 90 that receives the program may expand the program into main memory 92 and execute the above-mentioned processing. In at least one embodiment, storage 93 is a non-transitory tangible storage medium.

The program may also be one that realizes some of the functions described above. Furthermore, the program may be one that realizes the functions described above in combination with other programs already stored in storage 93, that is, a so-called differential file (differential program).

Second Embodiment
The second embodiment will be described with reference to Figures 7 and 8. Note that the same or corresponding reference numerals will be used to designate the same components as those in the first embodiment, and the description thereof will be omitted.

System Configuration
7 is a perspective view of a work machine 10 according to the second embodiment. The work machine 10 according to the second embodiment is, for example, a hydraulic excavator. The work machine 10 includes a traveling body 210, a rotating body 220, a work implement 230, a cab 240, and a machine room 250. The traveling body 210 and the rotating body 220 form a vehicle body.

The running body 210 supports the work machine 10 so that the work machine 10 can run. The running body 210 has a pair of left and right tracks. The work machine 10 moves forward, turns, or reverses by rotation of the pair of tracks.
The rotating body 220 is rotatably supported by the running body 210. The rotating body 220 is rotated relative to the running body 210 by a swing motor 256 described later. The rotating body 220 supports a work machine 230, a cab 240, a machine room 250, and a fuel cell 143.

The working implement 230 is operably supported on the body of the work machine 10. The working implement 230 includes a boom 231, an arm 232, and an attachment 233 which is a working tool. The attachment 233 is an example of a working tool. In the example shown in FIG. 1, the attachment 233 is a bucket. The base end of the boom 231 is rotatably attached to the rotating body 220. The base end of the arm 232 is rotatably attached to the tip of the boom 231. The attachment 233 is rotatably attached to the tip of the arm 232.

The work machine 230 is driven by a number of actuators. The actuators include, for example, a boom cylinder 231C, an arm cylinder 232C, and an attachment cylinder 233C.

The boom cylinder 231C is a hydraulic cylinder for driving the boom 231. A base end of the boom cylinder 231C is attached to the rotating body 220. A tip end of the boom cylinder 231C is attached to the boom 231.
The arm cylinder 232C is a hydraulic cylinder for driving the arm 232. A base end of the arm cylinder 232C is attached to the boom 231. A tip end of the arm cylinder 232C is attached to the arm 232.
The attachment cylinder 233C is a hydraulic cylinder for driving the attachment 233. A base end of the attachment cylinder 233C is attached to the arm 232. A tip end of the attachment cylinder 233C is attached to the attachment 233.

The operator's cab 240 of the work machine 10 is equipped with an operating device 162 for operating the work machine 10 .
The operation device 162 is provided in the cab 240 and receives operations by an operator. The operation device 162 includes, for example, operation levers for operating the revolving body 220, the boom 231, the arm 232, and the attachment 233, a foot pedal for operating the running body 210, a travel lever for operating the running body 210, and the like.

Figure 8 is a schematic block diagram showing the configuration of the power system 14 and drive system 15 of the work machine 10 according to the second embodiment. The drive system 15 has an inverter 151, a pump drive motor 152, a hydraulic pump 153, a hydraulic actuator 255, an inverter 155, and a swing motor 256. The inverter 151 converts DC current from the bus B into three-phase AC current and supplies it to the pump drive motor 152. The pump drive motor 152 generates power for driving the work machine 230 and the traveling body 210. The pump drive motor 152 rotates by the supplied three-phase AC current and drives the hydraulic pump 153. The hydraulic pump 153 discharges hydraulic oil to be supplied to the hydraulic actuator 255. The hydraulic oil discharged from the hydraulic pump 153 is supplied to the hydraulic actuator 255 via a control valve (not shown). The hydraulic actuator 255 is driven by the supplied hydraulic oil. The hydraulic actuator 255 includes a boom cylinder 231C, an arm cylinder 232C, an attachment cylinder 233C, and a hydraulic travel motor 234. The rotational force generated by the hydraulic travel motor 234 is transmitted to the traveling body 210. The inverter 155 converts the direct current from the bus B into a three-phase alternating current and supplies it to the swing motor 256. The swing motor 256 generates power for swinging the swing body 220. The swing motor 256 rotates by the supplied three-phase AC power and swings the swing body 220 relative to the traveling body 210. The swing motor 256 performs a power running operation for driving the swing body 220 to swing, and a regenerative operation for generating regenerative power to brake the swing body 220.

The control device 163 (see FIG. 3) according to the second embodiment causes the traveling body 210 to travel in accordance with the amount of operation of the operating device 162. The control device 163 drives the working machine 230 in accordance with the amount of operation of the operating device 162. The control device 163 causes the rotating body 220 to rotate in accordance with the amount of operation of the operating device 162.

The vehicle body control unit 173 (see FIG. 3) according to the second embodiment generates control signals for controlling the running of the running body 210, the drive of the work machine 230, and the rotation of the rotating body 220, depending on the amount of operation of the operating device 162.

<Action and Effects>
As described above, the control device 163 according to the second embodiment can determine the power to be output by the fuel cell 143 so that a power shortage does not occur depending on the working state of the work machine 10 or the state of the battery 144. The work machine 10 may require more power when operating a plurality of motors. For example, when the operator performs a combined operation on the work machine 10 by simultaneously rotating the revolving body 220 and driving the work implement 230, the work machine 10 requires more power. More specifically, when the revolving body 220 is rotated while raising the boom 231 or the arm 232 with a load loaded on the attachment 233, the work machine 10 requires more power. In addition, for example, the maximum dischargeable power of the battery 144 may decrease due to a decrease in the charging rate or an increase in temperature of the battery 144. At this time, the control device 163 can increase the output of the fuel cell 143 when the required power exceeds the sum of the standard generated power of the fuel cell 143 and the maximum dischargeable power of the battery 144. In other words, the control device 163 can appropriately determine the electric power that should be output by the fuel cell 143 mounted on the work machine 10 .

The control device 163 according to the second embodiment can determine the power to be output by the fuel cell 143 so that regeneration lapse due to the power generated by the fuel cell 143 does not occur. For example, when braking the revolving body 220 with excavation material loaded on the attachment 233, the revolving motor 256 may generate more regenerative power. For example, when braking the revolving body 220 placed on a slope, the revolving motor 256 may generate more regenerative power. For example, the maximum chargeable power of the battery 144 may decrease due to an increase in the charging rate or temperature of the battery 144. In this case, the control device 163 can limit the output of the fuel cell 143 when the sum of the regenerative power and the standard power generated by the fuel cell 143 exceeds the maximum chargeable power of the battery 144. In other words, the control device 163 can appropriately determine the power to be output by the fuel cell 143 mounted on the work machine 10.

Other Embodiments
Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes are possible. That is, in other embodiments, the order of the above-mentioned processes may be changed as appropriate. Also, some of the processes may be executed in parallel.
The control device 163 according to the embodiments described above may be configured by a single computer 90. Moreover, the control device 163 may function as the control device 163 by distributing the configuration of the control device 163 among multiple computers 90, and the multiple computers 90 cooperate with each other. In this case, some of the computers 90 constituting the control device 163 may be mounted inside the work machine 10, and other computers 90 may be provided outside the work machine 10. For example, when the work machine 10 according to the other embodiments is remotely operated, configurations other than the fuel cell control unit 178 and the battery control unit 179 may be provided in a remote computer 90.

In addition, the standard determination unit 172 of the control device 163 according to the embodiment described above determines the standard generated power based on the charging rate of the battery 144, but is not limited to this. For example, in other embodiments, the standard generated power may be determined independently of the charging rate of the battery 144.

The regenerative power identifying unit 175 in the embodiment described above identifies the regenerative power generated by the work machine 10 based on the measurement data of the voltage of the bus bar B and the current passing through the inverter 155 acquired by the data acquisition unit 171, but is not limited to this. For example, in another embodiment, the measurement device 161 may include a current sensor that measures the current passing through the inverter 151, and the regenerative power identifying unit 175 may identify the regenerative power generated by the work machine 10 based on the measurement data of the current passing through the inverter 151.

Furthermore, the work machine 10 according to the embodiment described above is equipped with a retarder grid 146 that consumes surplus power, but is not limited to this. For example, the work machine 10 according to other embodiments may not be equipped with a retarder grid 146, and may be configured so that surplus power is consumed by the pump drive motor 152 or an auxiliary device mounted on the work machine 10.

In the above-described embodiment, a dump truck or a hydraulic excavator is used as an example of the work machine 10 having a fuel cell 143 and a battery 144 and a work implement, but this is not limited to this. For example, the work machine according to other embodiments may be other work machines such as a bulldozer, a wheel loader, a crane, a forklift, or a motor grader.

In addition, the vehicle body control unit 173 according to the embodiment described above generates a control signal for controlling the work machine 10 based on the amount of operation of the operation device 162, but this is not limited to this. For example, when the work machine 10 is controlled by an external control system, the vehicle body control unit 173 may generate a control signal for controlling the work machine 10 based on an operation command transmitted from the external control system. Also, for example, when the work machine 10 operates autonomously, the measurement device 161 may further collect data on the position and orientation of the work machine 10, the topography around the work machine 10, and the work plan. The control device 163 may have an operation signal generation unit for generating an operation signal based on the measurement data collected by the measurement device 162. The vehicle body control unit 173 may generate a control signal for controlling the work machine 10 based on the operation command generated by the operation signal generation unit.

10...Working machine 11...Dump body 12...Vehicle body 13...Traveling device 14...Power system 141...Hydrogen tank 142...Hydrogen supply device 143...Fuel cell 144...Battery 145...DC-DC converter 146...Retarder grid 15...Drive system 151...Inverter 152...Pump drive motor 153...Hydraulic pump 154...Hoist cylinder 155...Inverter 156...Travel drive motor 16...Control system 161...Measuring device 162...Operation device 163...Control device 171...Data acquisition unit 172...Standard determination unit 173...Vehicle control unit 174... Required power calculation section 175...Regenerative power determination section 176...Battery capacity determination section 177...Control amount determination section 178...Fuel cell control section 179...Battery control section 181...First subtraction block 182...Second subtraction block 183...MAX block 184...First MIN block 185...Division block 186...Third subtraction block 187...Second MIN block 188...Addition block 189...Third MIN block 190...Fourth subtraction block 90...Computer 91...Processor 92...Main memory 93...Storage 94...Interface B...Bus line

Claims (10)

A control system for controlling a work machine having a fuel cell and a power storage device, the control system comprising:
a required power determination unit that determines the magnitude of required power necessary for operation of the work machine;
a fuel cell control unit that controls the fuel cell based on a standard generated power of the fuel cell, a maximum dischargeable power of the power storage device, and the required power;
A control system comprising: the fuel cell control unit controls the fuel cell to output power larger than the standard power generation power when a sum of the standard power generation power and the maximum dischargeable power is smaller than the required power.
The control system of claim 1 . a regenerative power identification unit that identifies the magnitude of regenerative power generated by the work machine,
the fuel cell control unit controls the fuel cell to output power less than the standard generated power or to stop generating power when the sum of the standard generated power and the regenerated power is greater than a maximum chargeable power of the power storage device.
The control system of claim 2. the fuel cell control unit controls the fuel cell to output the standard generated power when a sum of the standard generated power and a maximum dischargeable power of the power storage device is greater than the required power and a sum of the standard generated power and the regenerative power is smaller than a maximum chargeable power of the power storage device.
The control system of claim 3. a standard determination unit that determines the standard generated power based on the charging rate of the power storage device;
The control system of claim 1 . a power storage device control unit that controls the power storage device so as to discharge an amount of power corresponding to a difference between the power output by the fuel cell and the required power;
The control system of claim 1 . a power storage device control unit that controls the power storage device so as to store the power equivalent to the sum of the power output by the fuel cell and the regenerative power;
The control system of claim 3 . The work machine includes a consumption device that consumes surplus power,
the power storage device control unit controls the power storage device so as to charge the maximum chargeable power when a sum of the power output by the fuel cell and the regenerative power is greater than the maximum chargeable power.
8. The control system of claim 7. A work machine having a fuel cell, a power storage device, and the control system described in any one of claims 1 to 7, and having a work implement. A control method for a work machine including a fuel cell and a power storage device and having a work implement, comprising:
determining a required amount of electrical power required to operate the work machine;
controlling the fuel cell based on a standard power generation amount of the fuel cell, a maximum dischargeable power of the power storage device, and the required power;
A control method comprising:

Images