Control device, charging system, work vehicle, charging control method, and computer program

Abstract

A work vehicle according to the present invention comprises a charging inlet, a battery that stores power supplied from a charger via the charging inlet, an electric motor that runs on power supplied from the battery, a first power system for supplying power from the charger to the battery, and a second power system for supplying power from the charger to the electric motor without the mediation of the battery. A control device according to the present invention controls power supply from a charger to an electric work vehicle and is configured or programmed to acquire a vehicle power consumption that includes the power consumption of an electric motor of the work vehicle and to limit output current at the charger in accordance with comparison results for the vehicle power consumption and an upper limit output for the charger.

Description

Control Device, Charging System, Work Vehicle, Charging Control Method, and Computer Program

[0001] The present disclosure relates to a control device, a charging system, a work vehicle, a charging control method, and a computer program.

[0002] In the field of automobiles whose main purpose is to move people or objects, electric vehicles (EVs) that generate driving force (traction) for driving by an electric motor (hereinafter sometimes simply referred to as "motor") instead of an internal combustion engine are becoming more and more popular.

[0003] On the other hand, in order to realize a decarbonized society, it is required to reduce the amount of carbon dioxide (CO ２ ) emitted by work vehicles such as tractors used in fields. Different from general automobiles, work vehicles such as tractors need to tow work implements (agricultural implements) to perform agricultural operations such as tilling. Therefore, in order to realize the electrification of work vehicles, there are problems to be solved that are different from the electrification of passenger cars.

[0004] Patent Document 1 discloses an electric tractor that distributes and supplies electric power from a battery to a plurality of electric motors. The electric tractor includes a hydraulic pump, a pump motor, a PTO motor, a traveling motor, a battery, and an electric drive controller. The pump motor is an electric motor that drives the hydraulic pump. The PTO motor is an electric motor that drives the PTO shaft. The traveling motor is an electric motor that drives the traveling body to travel. The battery supplies electric power to the pump motor, the PTO motor, and the traveling motor. The electric drive controller controls the distribution of electric power to the pump motor, the PTO motor, and the traveling motor.

[0005] Patent Document 2 discloses a control device capable of suppressing deterioration due to overcharging of a battery mounted on an electric work vehicle. The control device comprises a motor, a battery, a power supply unit capable of supplying power to the motor and battery from an external power source, and a mode switching unit that switches from a first charging mode to a second charging mode. In the first charging mode, the battery is charged by power supplied from an external power source, and in the second charging mode, the battery is rechargeable and the motor is driven by power from at least one of the external power source or the battery. In the charging control, the cell voltage of each battery cell is monitored, and after the DC voltage of the battery reaches an upper limit, constant voltage control is performed to prevent the battery from overcharging.

[0006] Japanese Patent Publication No. 2023-66721 Japanese Patent Publication No. 2024-044438

[0007] Conventional work vehicles equipped with internal combustion engines inevitably consume fossil fuels and emit greenhouse gases. On the other hand, electric work vehicles still face various challenges that need to be addressed, such as ensuring safety, improving driving performance, improving charging control, reducing environmental impact, improving convenience, and lowering costs.

[0008] This disclosure provides an electric work vehicle capable of solving at least one of these problems.

[0009] This disclosure provides solutions as described in the following items.

[0010] [Item 1] A control device for controlling the supply of power from a charger to an electric work vehicle, wherein the work vehicle comprises: a charging inlet; a battery for storing power supplied from the charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; and a second power system for supplying power from the charger to the electric motor without going through the battery, and comprises one or more processors, wherein the one or more processors acquire vehicle power consumption, including the power consumption of the electric motor of the work vehicle, and are configured or programmed to cause the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle power consumption.

[0011] [Item 2] The control device according to Item 1, comprising a communication interface capable of communicating with the charger, wherein the one or more processors are configured or programmed to transmit a current limiting command to the charger via the communication interface to cause the charger to limit the output current.

[0012] [Item 3] The control device according to Item 1 or 2, wherein the one or more processors, when the vehicle power consumption is less than the upper limit output of the charger, limit the output current from the charger to the sum of the vehicle power consumption current determined from the vehicle power consumption and the charging current required to charge the battery, and supply the charging current to the first power system and supply a current equivalent to the vehicle power consumption current to the second power system; and when the vehicle power consumption exceeds the upper limit output of the charger, limit the output current to the upper limit output current determined from the upper limit output of the charger, and supply the upper limit output current to the second power system.

[0013] [Item 4] A control device according to any one of items 1 to 3, comprising one or more electric devices different from the electric motor, wherein the one or more processors estimate the vehicle power consumption from a predicted value of the sum of the power consumption of the one or more electric devices and the power consumption of the electric motor.

[0014] [Item 5] A control device according to any one of items 1 to 3, comprising one or more electric devices different from the electric motor, wherein the one or more processors estimate the vehicle power consumption based on the past operating history of the one or more electric devices.

[0015] [Item 6] The control device according to Item 3, wherein the one or more processors determine the amount of the charging current according to the characteristics of the battery.

[0016] [Item 7] The control device according to Item 3, wherein the one or more processors determine the amount of the charging current according to the current charge level of the battery.

[0017] [Item 8] The control device according to any one of items 1 to 5, wherein the work vehicle is equipped with a PTO shaft for supplying power to the work machine, the electric motor is an electric motor for driving the PTO shaft, and when charging of the work vehicle from the charger begins, the control device starts the electric motor, and while the work vehicle is performing work with the electric motor running, the control device causes the charger to limit the output current according to the result of comparing the upper limit output of the charger with the power consumption of the vehicle.

[0018] [Item 9] A charging system comprising a control device described in any one of items 1 to 8, and a warning device, wherein the control device causes the warning device to warn that the power supplied from the charger is insufficient when the vehicle power consumption exceeds the upper limit output of the charger.

[0019] [Item 10] A work vehicle comprising: a charging inlet; a battery that stores power supplied from a charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; a second power system for supplying power from the charger to the electric motor without going through the battery; and a control device as described in any one of items 1 to 8.

[0020] [Item 11] A control method implemented in a computer for controlling the supply of power from a charger to an electric work vehicle, the work vehicle comprising: a charging inlet; a battery for storing power supplied from the charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; and a second power system for supplying power from the charger to the electric motor without going through the battery, the control method comprising: obtaining the vehicle power consumption, including the power consumption of the electric motor of the work vehicle; and causing the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle power consumption.

[0021] [Item 12] A computer program used to control the supply of power from a charger to an electric work vehicle, wherein the work vehicle comprises: a charging inlet; a battery that stores power supplied from the charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; and a second power system for supplying power from the charger to the electric motor without going through the battery, and the computer program causes the computer to perform the following actions: obtain the vehicle power consumption, including the power consumption of the electric motor of the work vehicle; and cause the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle power consumption.

[0022] [Item 13] A control device configured to perform the method described in Item 11.

[0023] [Item 14] A computer-readable non-temporary storage medium that stores a computer program containing instructions for causing a computer to perform the actions described in Item 11.

[0024] [Item 15] A system comprising the control device described in Item 13, and two or more electric motors.

[0025] [Item 16] A control device for controlling the supply of power from a charger to an electric work vehicle, wherein the work vehicle comprises: a charging inlet; a battery for storing power supplied from the charger through the charging inlet; an electric motor that operates by receiving power from the battery; a first power system for supplying power from the charger to the battery; a second power system for supplying power from the charger to the electric motor without going through the battery; and a control device comprising: an acquisition unit for acquiring vehicle power consumption including the power consumption of the electric motor of the work vehicle; a comparison unit for comparing the upper limit output of the charger with the vehicle power consumption; and a limiting unit for causing the charger to limit the output current according to the comparison result of the comparison unit.

[0026] [Item 17] A system comprising the control device described in Item 16, and two or more electric motors.

[0027] Comprehensive or specific embodiments of the present invention may be realized by apparatus, systems, methods, integrated circuits, computer programs, or computer-readable non-temporary storage media, or any combination thereof. The computer-readable storage media may include volatile storage media or non-volatile storage media. The apparatus may consist of multiple devices. If the apparatus consists of two or more devices, these two or more devices may be located in a single device or in two or more separate devices.

[0028] According to embodiments of this disclosure, a control device is provided that controls the output current from a charger, which is capable of reducing the degradation of a battery mounted on an electric work vehicle.

[0029] This is a schematic plan view showing an example of the basic configuration of a work vehicle according to an exemplary embodiment of the present invention. This is a side view of a work vehicle according to an exemplary embodiment of the present invention. This is a top view of a work vehicle according to an exemplary embodiment of the present invention. This is a block diagram showing an example of the main components of a work vehicle and their connection relationships. This is a block diagram showing an example of the configuration of a power converter and its connection to other equipment. This is a block diagram showing an example of the hardware configuration of each ECU. This is a block diagram showing an example of the configuration of a power distribution unit. This is a block diagram showing a power system for charging in an exemplary embodiment of the present invention. This is a flowchart showing an example of a procedure for limiting the output current from a charger based on vehicle power consumption in an exemplary embodiment of the present invention. This is a schematic diagram showing an example of a warning image that pops up on a display.

[0030] Embodiments of the present invention will be described below. However, unnecessarily detailed descriptions may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid the following description becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present invention, and not to limit the subject matter described in the claims. In the following description, components having the same or similar function are denoted by the same reference numerals.

[0031] The following embodiments are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to these embodiments. For example, the numerical values, shapes, materials, steps, and order of steps shown in the following embodiments are merely examples, and various modifications are possible as long as they do not create a technical inconsistency. Furthermore, it is possible to combine one embodiment with other embodiments. The size and positional relationships of the components shown in each drawing may be exaggerated for ease of understanding.

[0032] (Definition of Terms) In this specification, “work vehicle” means a vehicle used for a specific task, such as agricultural work or construction work. “Work” may be, for example, agricultural work, construction work, rubble removal work, or snow removal work. Agricultural work vehicles may be, for example, tractors, combine harvesters, rice transplanters, riding cultivators, vegetable transplanters, vegetable harvesters, mowers, seeders, fertilizer spreaders, sprayers, or broadcasters. Construction work vehicles may be, for example, backhoes, wheel loaders, or carriers. An agricultural work vehicle such as a tractor or combine harvester, or a construction work vehicle, may function as a “work vehicle” on its own, or the work vehicle and any implements attached to or towed by it may function as a single “work vehicle.” Agricultural work vehicles perform agricultural tasks on the ground within a field (or work area), such as tilling, sowing, pest control, fertilizing, planting crops, or harvesting. Construction vehicles perform tasks such as transporting soil, rubble, and other materials at construction sites. These tasks are sometimes referred to as "ground work" or simply "work." When a construction vehicle moves while performing work, it is sometimes referred to as "work driving."

[0033] An "electric work vehicle" refers to a work vehicle that runs using an electric motor as its power source. An electric work vehicle may also be equipped with an internal combustion engine as an auxiliary power source in addition to the electric motor. Alternatively, an electric work vehicle may be equipped with an electric motor as an auxiliary power source in addition to the internal combustion engine. An electric work vehicle is equipped with an electrical energy source, such as a battery or fuel cell, to supply power to the electric motor. In the following description, an "electric work vehicle" may be simply referred to as a "work vehicle."

[0034] Electric motors can be synchronous motors such as permanent magnet synchronous motors or reluctance motors, or asynchronous motors such as induction motors.

[0035] A battery is an energy storage device that stores the electrical energy necessary for the operation of electric motors and other electrical components mounted on a work vehicle and / or work machine. A fuel cell is a power generation device that generates such electrical energy from a fuel such as hydrogen. An electrical energy source can be realized by an energy storage device, a power generation device, or a combination of an energy storage device and a power generation device. Furthermore, an electric work vehicle may obtain electrical energy from an electrical energy source located at a distance from the vehicle (e.g., on the ground or on another vehicle) via wired or wireless means.

[0036] When an electric work vehicle performs various "tasks" while moving or stationary, the power required for those tasks may be obtained from electric motors. An electric work vehicle is equipped with one or more electric motors. If an electric work vehicle is equipped with multiple electric motors, certain electric motors may output the driving force required for movement, while other electric motors may output the driving force required for the "tasks." If some or all of the "tasks" are performed by a work machine, the driving force can be mechanically transmitted from one or more electric motors on the electric work vehicle to the work machine. Such mechanical transmission of driving force can be achieved via a power transmission shaft called a power take-off (PTO) shaft.

[0037] The work machine itself may be equipped with an electric motor for the work. In this case, power may be supplied to the electric motor of the work machine from an electrical energy source such as a battery or fuel cell equipped in the electric work vehicle. The work machine may also be equipped with an electrical energy source that stores the power required for the work.

[0038] A "control device" (controller) is a device that controls the operation of part or all of a work vehicle. One example of a "control device" is a computing device comprising at least one processor and at least one memory that stores a computer program (code) that defines the control process executed by the processor. Another example of a "control device" is a computing device with a hardware accelerator such as an FPGA (Field-Programmable Gate Array), ASSP (Application Specific Standard Product), or ASIC (Application-Specific Integrated Circuit) configured or programmed to execute the control process. A control device may also be a collection of multiple devices. For example, several computing devices such as physically separated electronic control units (ECUs) may work together to function as a "control device".

[0039] A "processor" is a hardware electronic circuit such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), ISP (Image Signal Processor), or NPU (Neural Network Processing Unit).

[0040] "Memory" refers to hardware electronic circuits such as ROM (Read Only Memory) or RAM (Random Access Memory). Part of the memory may be a storage medium connected to the processor via wiring or a network. These hardware electronic circuits may be implemented by one or more integrated circuits (ICs) or large-scale integrated circuits (LSIs). Each functional unit or block and associated component within the electronic circuit may be manufactured individually as separate integrated circuit chips, or some or all of these functional units or blocks may be combined and manufactured as a single integrated circuit chip. Memory may store computer programs (hereinafter sometimes simply referred to as "programs") that define the operation of the processor. The programs are designed to cause the processor to perform one or more functions, operations, steps, or processes in embodiments of the present invention.

[0041] (Embodiments) Hereinafter, with reference to the drawings, several embodiments of the present invention applied to an electric agricultural tractor, which is an example of an electric work vehicle, will be described. The various technologies described for tractors in the following description can also be applied to agricultural machinery other than tractors, construction vehicles used at construction sites, work vehicles used at disaster sites, snowplows used in heavy snow areas, and vehicles for transporting goods, etc.

[0042] In the following explanation, the direction of arrow F in the diagram will be referred to as "forward," the direction of arrow B as "backward," the direction of arrow L as "left," the direction of arrow R as "right," the direction of arrow U as "up," and the direction of arrow D as "down."

[0043] <1. Basic Configuration of the Work Vehicle> Figure 1 is a schematic plan view showing an example of the basic configuration of a work vehicle 10 according to an exemplary embodiment of the present invention. The work vehicle 10 shown is an electric tractor for agricultural use. The work vehicle 10 can travel within a field while carrying or towing implements and performing agricultural work according to the type of implement. The work vehicle 10 can also travel within and outside of a field (including roads) with the implement lifted or without the implement attached.

[0044] The work vehicle 10 includes a vehicle body (vehicle frame) 11 that rotatably supports the left and right front wheels 14F and the left and right rear wheels 14R. The vehicle body 11 includes a front frame 12 provided with the front wheels 14F and a transmission case 13 provided with the rear wheels 14R. The front frame 12 is fixed to the front portion of the transmission case 13. The front wheels 14F and the rear wheels 14R may be collectively referred to as "wheels 14". Strictly speaking, the wheels 14 are wheels, and tires are mounted on the wheels 14. In the present disclosure, "wheel" generally means the whole of "wheel and tire". One or both of the front wheels 14F and the rear wheels 14R may be replaced with a plurality of wheels (crawlers) equipped with an endless track instead of a wheel with a tire.

[0045] In the example of FIG. 1, the work vehicle 10 includes a battery 20 and an electric motor 30 (hereinafter simply referred to as "motor 30") that are directly or indirectly supported by the front frame 12. The battery 20 may be configured as a battery pack including a plurality of cells connected in series, for example. The battery 20 is a rechargeable battery that outputs a relatively large voltage, such as a lithium-ion battery or a all-solid-state battery, for example. The battery 20 stores electric power for driving the motor 30. The battery 20 may be housed in a front housing called a "bonnet", for example. The front housing is supported by the front frame 12 at the front portion of the vehicle body 11.

[0046] Motor 30 is electrically connected to battery 20. Motor 30 can convert the electric power output from battery 20 into mechanical motion (power) and generate the driving force (traction) required for the running of work vehicle 10. Motor 30 can be, for example, an AC synchronous motor. Battery 20 generates a direct current. Therefore, when motor 30 is an AC synchronous motor, an electric circuit group including an inverter device (hereinafter sometimes simply referred to as "inverter") can be provided between battery 20 and motor 30. The direct current is converted into an alternating current by the inverter device. A part of such an electric circuit group may be inside battery 20. Also, another part of the electric circuit group may be attached to motor 30 as a drive circuit of motor 30.

[0047] Motor 30 has a rotating output shaft 33. The torque of output shaft 33 is transmitted to rear wheel 14R via mechanical components such as a transmission (speed change device) provided inside transmission case 13 and a rear wheel differential device (differential gear device). In other words, the power generated by motor 30, which is a power source, is transmitted to rear wheel 14R by a power transmission system (drive train) 34 including a transmission provided inside transmission case 13. For this reason, the "transmission case" may be called the "mission case". In the four-wheel drive mode, a part of the power of motor 30 is also transmitted to front wheel 14F. Thus, motor 30 drives a running device including a plurality of wheels 14.

[0048] The power of motor 30 may be used not only for the running of work vehicle 10 but also for driving a work implement. A PTO shaft 40 is provided at the rear end of transmission case 13. A work implement can be connected to PTO shaft 40. PTO shaft 40 can be driven by motor 30 that drives the running device or another electric motor not shown in FIG. 1. The torque of output shaft 33 of motor 30 or the output shaft of another motor is transmitted to PTO shaft 40. The work implement attached to or towed by work vehicle 10 can receive power from PTO shaft 40 and perform operations according to various works. Motor 30 and power transmission system 34 may be collectively referred to as an electric power train.

[0049] As shown in Figure 1, the work vehicle 10 does not have an internal combustion engine such as a diesel engine, but is equipped with a battery 20 and a motor 30. The output shaft 33 of the motor 30 is mechanically coupled to a power transmission system 34, such as a transmission, in a transmission case 13. The motor 30 can efficiently generate torque over a relatively wide range of rotational speeds compared to an internal combustion engine. By using the power transmission system 34, including the transmission, it becomes easy to adjust the torque and rotational speed from the motor 30 over an even wider range by performing multi-stage or continuously variable speed changes. Therefore, it is possible to efficiently perform not only the movement of the work vehicle 10 but also a variety of tasks using work equipment.

[0050] Depending on the intended use or size of the work vehicle 10, some functions of the power transmission system 34 may be omitted. For example, some or all of the transmission responsible for the gear shifting function may be omitted. The number and mounting positions of the motors 30 are not limited to the example shown in Figure 1. Furthermore, the work vehicle may be a hybrid electric vehicle (HEV) equipped with an internal combustion engine such as a diesel engine as a power source in addition to electric motors.

[0051] The work vehicle 10 shown in Figure 1 is equipped with one motor 30. However, the work vehicle 10 may be equipped with multiple electric motors. For example, the work vehicle 10 may be equipped with a drive electric motor that drives a running gear including four wheels 14, and a PTO electric motor that drives the PTO shaft 40. The work vehicle 10 may be equipped with multiple PTO shafts (e.g., a rear PTO shaft, a mid PTO shaft, a front PTO shaft, etc.). In that case, one electric motor may drive multiple PTO shafts, or multiple electric motors may drive multiple PTO shafts. For example, the work vehicle 10 may be equipped with multiple electric motors, each driving a corresponding one of the multiple PTO shafts. The work vehicle 10 may be equipped with a front wheel electric motor that drives two front wheels 14F, and a rear wheel electric motor that drives two rear wheels 14R. Alternatively, the work vehicle 10 may be equipped with two electric motors for the front wheels, each driving one of the two front wheels 14F, and two electric motors for the rear wheels, each driving one of the two rear wheels 14R. In other words, the work vehicle 10 may be equipped with four electric motors, each driving one of the four wheels 14. Thus, the work vehicle 10 may be equipped with one or more electric motors for driving the running gear and one or more electric motors for driving one or more PTO shafts. By providing multiple electric motors, the work vehicle 10 can control the rotation of multiple wheels 14 and one or more PTO shafts more flexibly. In the following description, electric motors for driving may be referred to as "driving motors," and electric motors for PTOs may be referred to as "PTO motors."

[0052] <2. Specific Examples of Work Vehicles> Next, we will explain a more specific example of the configuration of work vehicle 10.

[0053] Figure 2 is a side view of a work vehicle 10 according to an exemplary embodiment of the present invention. Figure 3 is a top view of the work vehicle 10 according to this embodiment.

[0054] The work vehicle 10 shown in Figures 2 and 3 comprises a vehicle body 11 and a running gear supported by the vehicle body 11. The running gear includes various devices necessary for driving, such as left and right front wheels 14F, left and right rear wheels 14R, front axle 15F, rear axle 15R, and a rear wheel differential.

[0055] The vehicle body 11 comprises a front frame 12, a transmission case 13, and a housing frame 16. The front frame 12 is connected to the front of the housing frame 16. The transmission case 13 is connected to the rear of the housing frame 16. A first electric motor 30A and a second electric motor 30B are housed inside the housing frame 16. The first electric motor 30A is a driving motor and drives the running gear via a power transmission system in the transmission case 13. The second electric motor 30B is a PTO motor and drives the PTO shaft 40 and one or more hydraulic pumps. The first electric motor 30A and the second electric motor 30B may be electric motors capable of relatively high efficiency and high torque output, such as permanent magnet synchronous motors.

[0056] The front frame 12 is fitted with a front axle case 17F. The front axle case 17F supports the left and right front wheels 14F. The transmission case 13 includes a rear axle case 17R. The rear axle case 17R supports the left and right rear wheels 14R and transmits power to the rear wheels 14R.

[0057] A battery 20 is mounted on the front frame 12. The battery 20 is supported by the front frame 12 and housed inside the front housing 19 (bonnet). The battery 20 stores the power supplied to the first electric motor 30A and the second electric motor 30B. In other words, the battery 20 stores power for driving, operation, and hydraulic drive. In the following description, the battery 20 may be referred to as the "drive battery 20".

[0058] Above the housing frame 16 and the transmission case 13 are a steering wheel 53, a meter panel unit 54, a group of pedals 55 including the accelerator and brake, a group of switches 56 for work driving, and a driver's seat 52. A safety frame 51 is provided behind the driver's seat 52. The safety frame 51 is attached to the transmission case 13 and has a structure that extends upward. Inside the housing frame 16 are the first electric motor 30A and the second electric motor 30B.

[0059] The switch group 56 includes various operating devices such as switches, levers, and dials for adjusting the operation of the work vehicle 10 and the work implement. The switch group 56 includes various operating devices such as an accelerator lever for adjusting the travel speed, a switch for switching the PTO shaft 40 on and off, a dial for adjusting the rotational speed of the PTO shaft 40, and a lever for adjusting the height of the three-point linkage supporting the work implement. By operating the switch group 56, the driver can give various instructions to the work vehicle 10 for travel and work.

[0060] The meter panel unit 54 displays information regarding the status of the work vehicle 10. For example, the meter panel unit 54 displays various information such as the travel speed, the rotational speed of the PTO shaft 40, the height of the three-point linkage, the output of the motors 30A and 30B, the charge status of the battery 20, and the temperature of the battery 20. The meter panel unit 54 may be equipped with analog meters and / or a digital display (hereinafter sometimes simply referred to as "display") for displaying this information. The display of the meter panel unit 54 may display a graphical user interface (GUI) that allows the user to perform various setting operations related to the work vehicle 10. The user can perform various settings related to the work vehicle 10 on the display screen using an input device connected to the meter panel unit 54 or an input means such as a touchscreen mounted on the display.

[0061] As shown in Figure 3, a charging inlet 57 is provided to the right of the steering wheel 53. The charging inlet 57 is a device that includes a socket configured to allow connection of a charging adapter extending from an external power source or charger. Near the charging inlet 57, a device for the user to initiate charging, such as a charging start button, may be provided. When the user connects the charging adapter to the charging inlet 57 and performs a predetermined operation, such as pressing the charging start button, charging of the battery 20 begins.

[0062] The battery 20 can be charged using either normal charging or rapid charging. In normal charging, AC power supplied from an external AC power source is converted to high-voltage DC power (e.g., around 350V to 450V), and this DC power is supplied to the battery 20. In rapid charging, high-voltage DC power is directly supplied to the battery 20 from an external DC power source. The charging inlet 57 in this embodiment supports both normal and rapid charging. For normal charging, a commercial AC power source that outputs an AC voltage of, for example, 200V or 100V may be used as the power source. For rapid charging, a DC power source that outputs a DC voltage of, for example, around 350V to 450V may be used as the power source. Rapid charging can be performed using protocols compliant with standards such as CHAdeMO, NACS, CCS1, CCS2, GB / T, or ChaoJi.

[0063] The power stored in the battery 20 can also be output to external electrical equipment via the charging inlet 57. Such external power output is referred to as "external power supply" in this specification. External power supply is performed with an external power supply adapter connected to the charging inlet 57. The DC power from the battery 20 can be converted to AC power by a power converter in the work vehicle 10. This AC power can then be supplied to external equipment via the charging inlet 57 and the external power supply adapter.

[0064] As shown in Figure 3, the first electric motor 30A and the second electric motor 30B in this embodiment are arranged side by side. The first electric motor 30A and the second electric motor 30B are rotated by power supplied from the battery 20. The first electric motor 30A drives the running gear via a power transmission system in the transmission case 13. The second electric motor 30B drives the PTO shaft 40 and the hydraulic pump via a power transmission system in the transmission case 13. As a result, the second electric motor 30B drives the work implement and various hydraulic devices. The hydraulic devices may be used, for example, to change the height of the three-point linkage supporting the work implement. The work vehicle 10 may be equipped with a power steering system that assists the driver's steering wheel operation. In this case, the hydraulic devices may also be used in the power steering system to supply auxiliary force to change the steering angle of the front wheels 104F.

[0065] <3. System Configuration of the Work Vehicle> Figure 4 is a block diagram showing the main components of the work vehicle 10 and an example of their connection relationships. In Figure 4, connection relationships related to power transmission, high-voltage drive power, and low-voltage auxiliary power are represented by solid lines of different thicknesses. Connection relationships related to signals (digital signals and analog signals) are represented by dotted lines. Coolant flow is represented by thick dashed lines.

[0066] As shown in Figure 4, the work vehicle 10 is equipped with a first inverter 35A and a second inverter 35B. The first inverter 35A is connected to the first electric motor 30A. The second inverter 35B is connected to the second electric motor 30B. Each of the first inverter 35A and the second inverter 35B converts the DC voltage from the battery 20 into a three-phase AC voltage. The first inverter 35A supplies the converted three-phase AC voltage to the first electric motor 30A. This causes the first electric motor 30A to rotate and the traction device to be driven. The second inverter 35B also supplies the converted three-phase AC voltage to the second electric motor 30B. This causes the second electric motor 30B to rotate and the hydraulic pump 36 and the PTO shaft 40 to be driven.

[0067] The transmission case 13 houses the power transmission system 34A for driving, the power transmission system 34B for work, and the hydraulic pump 36. The power transmission system 34A for driving may include components such as a reduction gear, a sub-transmission, and a differential. The power transmission system 34A for driving transmits power from the rotation of the first electric motor 30A to the rear wheels 14R. In four-wheel drive mode, the power transmission system 34A for driving also transmits a portion of the power from the rotation of the first electric motor 30A to the front wheels 14F. The power transmission system 34B for work may include components such as a reduction gear, a PTO clutch, and a PTO transmission. The power transmission system 34B for work transmits power from the rotation of the second electric motor 30B to the hydraulic pump 36 and the PTO shaft 40. The PTO shaft 40 supplies power for work to the work implement.

[0068] The PTO shaft 40 shown in Figure 4 is the rear PTO shaft. In addition to the rear PTO shaft, the work vehicle 10 may also have a mid-PTO shaft or a front PTO shaft. If the work vehicle 10 has multiple PTO shafts, the power transmission system 34B may be configured to distribute the power generated by the rotation of the second electric motor 30B to the multiple PTO shafts. Alternatively, in addition to the second electric motor 30B that drives the PTO shaft 40, the work vehicle 10 may include other electric motors that drive the other PTO shafts.

[0069] The implements connected to the PTO shaft 40 may include, for example, a rotary tiller, a seeder, a spreader, a transplanter, a mower, a rake, a baler, a harvester, a sprayer, or a harrow. Any implement can be connected to the work vehicle 10 and used.

[0070] The hydraulic pump 36 is driven by power from the second electric motor 30B. The hydraulic pump 36 pressurizes the hydraulic fluid, thereby changing the height of the three-point linkage to which the work equipment is connected. Alternatively, the hydraulic pump 36 may be used in a hydraulic power steering system. If a front loader is mounted as the work equipment, the hydraulic pump 36 may be used in a hydraulic system that enables the lifting and lowering of the front loader. Power from the second electric motor 30B may be transmitted to multiple hydraulic pumps to drive these multiple hydraulic systems. Alternatively, the work vehicle 10 may have one or more electric motors for hydraulics separate from the second electric motor 30B.

[0071] In the example shown in Figure 4, the work vehicle 10 further comprises a power converter 58, a power distribution unit (PDU) 80, an auxiliary battery 21, and a battery temperature control system 70.

[0072] The power converter 58 is positioned between the charging inlet 57 and the battery 20 and performs power conversions such as AC to DC conversion and voltage conversion. Figure 5 shows an example of the configuration of the power converter 58 and its connection to other equipment. The power converter 58 shown in Figure 5 includes an onboard charger (OBC) 81 and a DC-DC converter 82. During normal charging, the OBC 81 converts AC power from the charging inlet 57 to DC power and supplies it to the drive battery 20 via the power distribution unit 80. The drive battery 20 is charged by this DC power. The DC-DC converter 82 is connected to the OBC 81 and also to the battery 20 via the power distribution unit 80. The DC-DC converter 82 converts the relatively high-voltage DC power output from the OBC 81 or the drive battery 20 to lower-voltage DC power (e.g., 12V or 24V). The low-voltage DC power converted by the DC-DC converter 82 is supplied to the auxiliary battery 21 and the auxiliary components 84. The auxiliary components 84 include several devices that operate on the relatively low voltage output from the DC-DC converter 82 or the battery 21. For example, the auxiliary components 84 include several electronic control units (ECUs) and other electrical components. The auxiliary battery 21 is charged by the DC voltage output from the DC-DC converter 82. The auxiliary battery 21 stores the power supplied to the auxiliary components 84, such as each ECU, the meter panel unit 54, the pumps 67, 77, and the air conditioner. The battery 21 may be, for example, a lead-acid battery.

[0073] Refer to Figure 4 again. The work vehicle 10 is equipped with multiple ECUs. The multiple ECUs include a main ECU 61, an electric ECU 62, and a charging ECU 63. The main ECU 61 controls the overall operation of the work vehicle 10 based on signals generated by the user operating the pedal group 55, the switch group 56, and the meter panel unit 54. The electric ECU 62 mainly controls the charging and discharging of the battery 20 and the operation of the electric motors 30A and 30B. The charging ECU 63 communicates with an external charger (external power supply) and performs control to ensure smooth charging by appropriately controlling the relay 64.

[0074] In this embodiment, the combination of the main ECU 61, the electric ECU 62, and the charging ECU 63 functions as a "control device" that controls the operation of the work vehicle 10. Therefore, in the following description, the operations performed by the main ECU 61, the electric ECU 62, and the charging ECU 63 all correspond to operations performed by the "control device". These ECUs can communicate with each other according to a vehicle bus standard such as CAN (Controller Area Network). Instead of CAN, a faster communication method such as on-board Ethernet (registered trademark) may be used. An on-board computer integrating at least some of the functions of the main ECU 61, the electric ECU 62, and the charging ECU 63 may be provided as the "control device". The control device may include ECUs other than the main ECU 61, the electric ECU 62, and the charging ECU 63. Each ECU may be a computing device including one or more processors and one or more memories. Each ECU can perform the operations described later by having the processor execute a computer program stored in the memory.

[0075] The electric ECU 62 sends control signals to the first inverter 35A and the second inverter 35B in response to signals from the pedal group 55 and the switch group 56. The electric ECU 62 can perform motor control based on a rotational speed command value or a torque command value determined, for example, according to the amount of operation of the pedal group 55 by the driver.

[0076] The electric ECU 62 controls the switching operation of multiple switch elements (e.g., MOSFETs) in the first inverter 35A and the second inverter 35B, respectively. Specifically, the electric ECU 62 generates control signals to control the switching operation of each switch element and outputs them to each inverter. The first inverter 35A converts the DC power from the battery 20 into three-phase AC power, which is a pseudo-sine wave of, for example, u-phase, v-phase, and w-phase, according to the control signals from the electric ECU 62, and supplies this three-phase AC power to the first electric motor 30A. Similarly, the second inverter 35B converts the DC power from the battery 20 into three-phase AC power, which is a pseudo-sine wave of, for example, u-phase, v-phase, and w-phase, according to the control signals from the electric ECU 62, and supplies this three-phase AC power to the second electric motor 30B. As a result, the electric ECU 62 can rotate the electric motors 30A and 30B at appropriate rotational speeds and torques according to the driver's operation.

[0077] While the work vehicle 10 is in operation, the main ECU 61 causes the meter panel unit 54 to display information regarding the status of the work vehicle 10. For example, the main ECU 61 displays information such as the travel speed, the operating status of the motors 30A and 30B, the charge status of the battery 20, and the status of the power transmission system 34A and the transmission included in 34A on the meter panel unit 54.

[0078] Figure 6 is a block diagram showing an example of the hardware configuration of each ECU. Each ECU 400 includes a processor 434, ROM 435, RAM 436, external I / F 437, and communication I / F 438. These components are interconnected via a bus 439.

[0079] ROM 435 is, for example, writable memory (e.g., PROM), rewritable memory (e.g., flash memory), or read-only memory. ROM 435 stores a program that controls the operation of the processor 434. ROM 435 does not have to be a single recording medium; it may be a collection of multiple recording media. Some of the multiple storage media may be removable memory.

[0080] RAM 436 provides a working area for temporarily unpacking the program stored in ROM 435 at boot time. RAM 436 does not need to be a single recording medium; it may be a collection of multiple recording media.

[0081] External I / F 437 is an interface for connecting to external devices. Communication I / F 438 is an interface for communicating with other electronic devices (e.g., sensors and other ECUs). For example, communication I / F 438 can perform wired communication compliant with various protocols such as CAN or Ethernet®. Communication I / F 438 may also perform wireless communication compliant with wireless communication standards such as Bluetooth® and / or Wi-Fi®.

[0082] The ECU may further include a storage device for storing data generated by the processor 434 for a relatively long period of time. Such a storage device may be, for example, a semiconductor storage device, a magnetic storage device, or an optical storage device, or a combination thereof.

[0083] The power distribution unit 80 shown in Figure 4 is a device that electrically connects equipment such as the charging inlet 57, power converter 58, battery 20, inverters 35A and 35B, and heater 72.

[0084] Figure 7 shows an example of the configuration of the power distribution unit 80. The power distribution unit 80 may have a plurality of relay circuits 83 (83a to 83g) that operate under the control of the electric ECU 62. During charging, the power distribution unit 80 is configured to supply power from the charging inlet 57 or the power converter 58 to the battery 20, and to the heater 72 when the temperature is low. On the other hand, during discharging, the power distribution unit 80 is configured to distribute power from the battery 20 to the first inverter 35A, the second inverter 35B, and the power converter 23. The electric ECU 62 may be configured or programmed to control the charging and discharging of the battery 20 by appropriately switching the on and off of the plurality of relay circuits 83a to 83g in the power distribution unit 80. In this specification, relay circuits may be simply referred to as "relays".

[0085] As shown in Figure 4, the battery 20 includes a battery management system (BMS) 22 and a temperature sensor 24. The BMS 22 is configured to monitor the state of the battery 20, such as the input voltage, output voltage, and temperature, and to control the charging and discharging currents to the battery 20 based on these states. The temperature sensor 24 may be configured to measure the temperature of each of the multiple cells contained in the battery 20.

[0086] The work vehicle 10 illustrated in Figure 4 is equipped with a cooling system 60 for high-voltage equipment and a battery temperature control system 70. The cooling system 60 is used to cool equipment to which high voltage is applied (also referred to as "high-voltage equipment"). The cooling system 60 comprises a radiator 65, a reservoir tank 66, a pump 67, and a cooling fan 68. In the example in Figure 4, the cooling system 60 is connected via hoses to the first inverter 35A, the first electric motor 30A, the second electric motor 30B, the second inverter 35B, and the power converter 58 in that order. This forms a flow path through which the coolant circulates. The coolant in the cooling system 60 is, for example, water or oil. The cooling system 60 cools these high-voltage equipment by circulating the coolant through the flow path. The coolant heated by the high-voltage equipment is cooled by heat dissipation in the radiator 65. The cooling fan 68 generates cooling air to cool the coolant inside the radiator 65. The cooling air promotes heat dissipation from the radiator 65.

[0087] The battery temperature control system 70 is used to cool or heat (also referred to as "heating") the battery 20. The battery temperature control system 70 comprises a heater 72, a radiator 75, a reservoir tank 76, and a pump 77. The battery temperature control system 70 is connected to the battery 20 via a hose. This creates a passage through which the coolant circulates. The coolant in the battery temperature control system 70 is, for example, water or oil. The battery temperature control system 70 cools the battery 20 by circulating the coolant through the passage. The coolant heated by the battery 20 is cooled by heat dissipation in the radiator 75. Cooling air from the cooling fan 68 also plays a role in cooling the coolant inside the radiator 75. The heater 72 raises the temperature of the battery 20 by warming the coolant. This makes it possible to suppress a decrease in the charge and discharge performance of the battery 20 even in low-temperature environments where the ambient temperature is, for example, below 0 degrees Celsius (°C).

[0088] The operation of the cooling system 60 and the battery temperature control system 70 is controlled by the electric ECU 62. For example, the electric ECU 62 is configured or programmed to maintain the temperature of the battery 20 within an appropriate range by controlling the battery temperature control system 70 based on the temperature of the battery 20 measured by the temperature sensor 24. In addition to the measurement value of the temperature sensor 24, the electric ECU 62 may also control the battery temperature control system 70 based on the measurement value of a temperature sensor 25 that measures the ambient temperature and is installed in the work vehicle 10.

[0089] The flow paths of the coolant in the cooling system 60 and the battery temperature control system 70 are not limited to the illustrated paths and can be changed as appropriate. The cooling method in the cooling system 60 and the battery temperature control system 70 is not limited to water cooling or oil cooling, but may also be air cooling. Alternatively, the refrigerant used in an air conditioner may be used instead of the above-mentioned coolant.

[0090] <4. Charging Control> An electric work vehicle is equipped with multiple electric devices, including motors, and a battery that stores the power supplied to the multiple electric devices. The multiple electric devices may include various electric devices such as inverters, BMS, radiators, heaters, and ECUs, as illustrated in Figure 4.

[0091] When a charging adapter is connected to the charging inlet, power is supplied to the battery from an external charger via the charging inlet, thereby charging the battery. Batteries tend to degrade with repeated charging and discharging. Batteries also tend to degrade with overcharging and discharging or with high current flow. Therefore, battery degradation can be reduced by avoiding repeated charging and discharging, overcharging and discharging, or supplying high current.

[0092] Work vehicles such as backhoes can operate in a stationary location while being charged by connecting to an external charger. In particular, when operating work vehicles while charging, improvements to the charging control are desirable in order to reduce battery degradation.

[0093] To solve the above problems, the control device in this embodiment is configured or programmed to control the power supply from the charger to the electric work vehicle. The work vehicle includes a charging inlet, a battery that stores power supplied from the charger through the charging inlet, a motor that operates on power supplied from the battery, a first power system for supplying power from the charger to the battery, and a second power system for supplying power from the charger to the motor without going through the battery. The motor is, for example, a PTO motor. However, as mentioned above, multiple motors, including a drive motor, a PTO motor, and a pump motor, may operate on power supplied from the battery. The battery charging method may be normal charging or rapid charging.

[0094] The control device may include one or more processors configured or programmed to acquire vehicle power consumption, including the power consumption of the work vehicle's motor, and to limit the output current of the charger according to the result of comparing the charger's upper limit output with the vehicle power consumption.

[0095] The control device in this embodiment may include a communication interface capable of communicating with the charger. The control device may be configured or programmed to send a current limiting command to the charger via the communication interface, causing the charger to limit the output current.

[0096] In one embodiment, the work vehicle may include a PTO shaft for supplying power to the work machine and a PTO motor for driving the PTO shaft. When charging of the work vehicle from the charger begins, the control device starts the PTO motor and, while the work vehicle is performing work with the PTO motor running, may cause the charger to limit the output current according to a comparison between the upper limit output of the charger and the vehicle's power consumption. When charging of the work vehicle from the charger begins, the control device may start the PTO motor and operate the hydraulic pump to start the hydraulic system.

[0097] The control method implemented in the computer that controls the power supply from the charger to the electric work vehicle in this embodiment is used for a work vehicle that includes a charging inlet, a battery that stores power supplied from the charger through the charging inlet, a motor that operates on power supplied from the battery, a first power system for supplying power from the charger to the battery, and a second power system for supplying power from the charger to the motor without going through the battery. The method includes obtaining the vehicle's power consumption, including the power consumption of the motor of the work vehicle, and causing the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle's power consumption.

[0098] A computer program containing a set of instructions that causes one or more computers to execute the above method of controlling the supply of power from a charger to an electric work vehicle may be manufactured and sold independently of the work vehicle. The computer program may be provided, for example, by being stored in a computer-readable non-temporary storage medium. The computer program may also be provided by download via a telecommunications line (e.g., the Internet).

[0099] According to the control device, charging system, work vehicle, charging control method, and computer program of this embodiment, a novel method for controlling the output current from a charger based on vehicle power consumption is provided, thereby reducing battery degradation, and in particular reducing battery degradation due to overcharging.

[0100] Figure 8 is a block diagram showing the power system for charging in this embodiment. The block diagram shown in Figure 8 corresponds to a simplified version of the block diagram shown in Figure 4, with the parts related to the power system for charging extracted.

[0101] The work vehicle 10 shown in Figure 8 includes a charging inlet 57, a battery 20 that stores power supplied from an external charger 90 via the charging inlet 57, a motor 30 that operates using power supplied from the battery 20, a first power system 70A, and a second power system 70B.

[0102] In this embodiment, the motor 30 is, for example, a PTO motor. The inverter 35 is, for example, a second inverter connected to the PTO motor (see Figure 4).

[0103] The first power system 70A connects the power distribution unit 80 to the battery 20, enabling power to be supplied from the charger 90 to the battery 20. The second power system 70B connects the power distribution unit 80 to the inverter 35, and also connects the inverter 35 to the motor 30, enabling power to be supplied from the charger 90 to the motor 30 without going through the battery 20.

[0104] The electric ECU 62 and charging ECU shown in Figure 4 may function as a control device 400 for controlling the output current from the charger, either individually or in cooperation. The control device 400 may acquire the vehicle power consumption, including the power consumption of the motor 30 of the work vehicle 10, and may be configured or programmed to limit the output current of the charger 90 according to the result of comparing the upper limit output of the charger 90 with the vehicle power consumption.

[0105] The control device 400 includes a communication interface 438 that enables communication with the charger 90, as shown in Figure 6. The charger 90 includes a controller 91 that controls the operation of the charger 90. The control device 400 and the controller 91 are connected to each other so as to be able to communicate with each other by wire or wireless. The controller 91 may be further connected so as to be able to communicate with the BMS 22 (see Figure 4) of the work vehicle 10.

[0106] Figure 9 is a flowchart showing an example of the procedure for limiting the output current from the charger based on the vehicle's power consumption in this embodiment.

[0107] (Step S101) As described above, when the user connects the charging adapter to the charging inlet and performs a predetermined operation such as pressing the charging start button, charging of the battery begins.

[0108] (Step S102) In this embodiment, when charging to the battery begins, the control device starts the PTO motor, which in turn starts the PTO shaft and hydraulic pump, for example, to operate the work equipment. For example, a work vehicle such as a backhoe can perform stationary work while being charged while connected to an external charger. Alternatively, when charging to the battery begins, the control device may start the PTO motor and the drive motor. In this case, the work vehicle can perform work in a state that is not completely stopped, as long as it is within the reach of the charging adapter extending from the charger.

[0109] (Step S103) Next, the control device obtains the vehicle power consumption, including the power consumption of the PTO motor of the work vehicle. For example, the control device may estimate the vehicle power consumption from a predicted sum of the power consumption of one or more electric devices and the power consumption of the PTO motor. One or more electric devices may include various electric devices such as inverters, BMS, radiators, heaters, and ECUs.

[0110] Motor power consumption refers to the power consumed by the motor, including losses such as copper losses, and can be estimated, for example, from the mechanical motor output that can be extracted from the motor's output shaft, which is expressed as the product of motor torque and rotational speed.

[0111] In this embodiment, the control device can estimate the vehicle's power consumption from a predicted value of the sum of the power consumption of one or more electric devices with relatively high power consumption (for example, the second inverter 35B, BMS 22, radiators 65 and 75 shown in Figure 4) and the power consumption of the PTO motor. The power consumption of the PTO motor can be estimated, for example, from the mechanical motor output that can be taken from the output shaft of the PTO motor.

[0112] The control device can estimate the vehicle's power consumption based on the past operating history of one or more electric devices. For example, the control device can estimate the power consumption of each electric device based on its past operating history, and then estimate the vehicle's power consumption from the sum of these predicted values ​​and the power consumption of the PTO motor.

[0113] (Step S104) Next, the control device compares the upper limit output of the charger with the estimated vehicle power consumption. The upper limit output of the charger means the upper limit of the amount of power that can be supplied to the work vehicles. The charger may have multiple charging ports. In this case, the upper limit of the amount of power supplied to each individual work vehicle is determined in general terms based on the upper limit output of the charger, and in more detail, it may be determined, for example, according to the number of work vehicles connected to the charging port and / or the specifications of the work vehicles.

[0114] (Step S105) If the estimated vehicle power consumption is below the upper limit output of the charger (YES in Step S105), the control device proceeds to the next step S106; if the vehicle power consumption exceeds the upper limit output of the charger (NO in Step S105), the control device proceeds to the next step S108.

[0115] (Step S106) The control device may limit the output current from the charger to the sum of the vehicle consumption current, which is determined from the vehicle's power consumption, and the charging current required to charge the battery. For example, the control device determines the vehicle consumption current from the estimated vehicle power consumption. The control device determines the sum of the vehicle consumption current and the charging current required to charge the battery.

[0116] The control device may determine the amount of charging current according to the battery characteristics. Alternatively, the control device may determine the amount of charging current according to the current charge level of the battery. In this way, the control device limits the output current from the charger to the sum of the vehicle's consumption current and the charging current. In other words, the control device limits the output current from the charger to the vehicle's consumption current plus an additional amount for battery charging.

[0117] (Step S107) The control device may limit the output current from the charger to the sum current determined in step S106 and send a current limit command to the controller 91 of the charger 90 to instruct the limiting to the sum current. The controller 91 may limit the output current to the sum current in response to the current limit command.

[0118] The control device controls multiple relay circuits (see Figure 7) provided in the power distribution unit, enabling power supply to the first and second power systems. The control device can supply a charging current to the first power system and a current equivalent to the vehicle's consumption current to the second power system, for example, by controlling the BMS. In this way, in addition to normal battery charging control, the control device can supply power from the charger to the PTO motor without going through the battery. With this control, normal charging is performed with a charging current determined, for example, according to the battery's characteristics or its current charge level, thereby reducing battery degradation due to overcharging. Furthermore, it becomes possible to operate the work equipment by supplying power directly from the charger to the PTO motor without going through the battery while the battery is being charged.

[0119] (Step S108) The control device determines the upper limit output current from the upper limit output of the charger. The control device may limit the output current from the charger to the upper limit output current. The control device may transmit a current limit command to the controller 91 of the charger 90 to indicate that the output current has been limited to the upper limit output current. The controller 91 may limit the output current to the upper limit output current in response to the current limit command.

[0120] The control unit controls multiple relay circuits (see Figure 7) provided in the power distribution unit to shut off the power supply to the first power system and open the power supply to the second power system, thereby supplying the upper limit output current to the second power system. With this control, if the vehicle's power consumption exceeds the upper limit output of the charger, power from the charger is not supplied to the battery, but only to the PTO motor. Therefore, it is possible to reduce battery degradation due to overcharging. Furthermore, it becomes possible to operate the work equipment by supplying power directly from the charger to the PTO motor without going through the battery.

[0121] (Step S109) The work vehicle may be equipped with a display device. An example of a display device is the display of the meter panel unit 54 shown in Figure 4. The control device may cause a warning device to warn that the power supplied from the charger is insufficient if the vehicle's power consumption exceeds the upper limit output of the charger.

[0122] Figure 10 is a schematic diagram showing an example of a warning image that pops up on the display. For example, the control device may pop up a warning image 99 on the display that includes a message warning that the power supplied from the charger is insufficient. Such a display makes it possible to warn the user that the vehicle's power consumption exceeds the power supplied from the charger. Upon receiving the warning, the user may take actions such as reducing the rotation speed of the PTO motor, stopping the PTO motor, or suppressing the operation of the work equipment.

[0123] The charging system in this embodiment comprises the control device and warning device described above. The charging system is suitably mounted on a work vehicle.

[0124] This invention is applicable to electric work vehicles in general.

[0125] 10...Work vehicle, 11...Body, 12...Front frame, 13...Transmission case, 14...Wheels, 14F...Front wheels, 14R...Rear wheels, 15F...Front axle, 15R...Rear axle, 16...Housing frame, 17F...Front axle case, 17R...Rear axle case, 19...Front housing, 20...Battery, 22...Battery management system (BMS), 24...Temperature sensor, 30, 30A, 30B, 30C...Electric motor, 33...Output shaft, 34...Power transmission system, 35, 35A, 35B...Inverter, 36...Hydraulic pump, 40...PTO shaft, 51...Rops frame, 52...Driver's seat, 53...Steering wheel, 54...Meter panel unit, 55...Pedal group, 56...Switch group, 57...Charging inlet 58... Power converter, 60... Cooling system for high-voltage equipment, 61... Main ECU, 62... Electric ECU, 63... Charging ECU, 64... Relay, 65... Radiator for high-voltage equipment, 66... ​​Reservoir tank, 67... Pump, 68... Cooling fan, 70... Battery temperature control system, 70A... First power system, 70B... Second power system, 72... Heater, 75... Battery radiator, 76... Reservoir tank, 77... Pump, 80... Power distribution unit, 81... Onboard charger (OBC), 82... DC-DC converter, 90... Charger, 91... Controller, 400... Control device

Claims

1. A control device for controlling the supply of power from a charger to an electric work vehicle, wherein the work vehicle comprises: a charging inlet; a battery for storing power supplied from the charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; and a second power system for supplying power from the charger to the electric motor without going through the battery, and comprises one or more processors, wherein the one or more processors acquire vehicle power consumption, including the power consumption of the electric motor of the work vehicle, and are configured or programmed to cause the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle power consumption.

2. The control device according to claim 1, comprising a communication interface capable of communicating with the charger, wherein the one or more processors are configured or programmed to transmit a current limiting command to the charger via the communication interface to cause the charger to limit the output current.

3. The control device according to claim 1 or 2, wherein, when the vehicle power consumption is less than the upper limit output of the charger, the one or more processors limit the output current from the charger to the sum of the vehicle power consumption current determined from the vehicle power consumption and the charging current required to charge the battery, and supply the charging current to the first power system and supply a current equivalent to the vehicle power consumption current to the second power system; and when the vehicle power consumption exceeds the upper limit output of the charger, the output current is limited to the upper limit output current determined from the upper limit output of the charger, and the upper limit output current is supplied to the second power system.

4. The control device according to claim 1 or 2, comprising one or more electric devices different from the electric motor, wherein the one or more processors estimate the vehicle power consumption from a predicted value of the sum of the power consumption of the one or more electric devices and the power consumption of the electric motor.

5. The control device according to claim 1 or 2, comprising one or more electric devices different from the electric motor, wherein the one or more processors estimate the vehicle power consumption based on the past operating history of the one or more electric devices.

6. The control device according to claim 3, wherein the one or more processors determine the amount of the charging current according to the characteristics of the battery.

7. The control device according to claim 3, wherein the one or more processors determine the amount of the charging current according to the current charge level of the battery.

8. The control device according to claim 1 or 2, wherein the work vehicle is equipped with a PTO shaft for supplying power to a work machine, the electric motor is an electric motor for driving the PTO shaft, and when charging of the work vehicle from the charger begins, the control device starts the electric motor, and while the work vehicle is performing work with the electric motor running, the control device causes the charger to limit the output current according to the result of comparing the upper limit output of the charger with the power consumption of the vehicle.

9. A charging system comprising: a control device according to claim 1 or 2; and a warning device, wherein the control device causes the warning device to warn that the power supplied from the charger is insufficient when the vehicle power consumption exceeds the upper limit output of the charger.

10. A work vehicle comprising: a charging inlet; a battery for storing power supplied from a charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; a second power system for supplying power from the charger to the electric motor without going through the battery; and the control device according to claim 1 or 2.

11. A control method implemented in a computer for controlling the supply of power from a charger to an electric work vehicle, the work vehicle comprising: a charging inlet; a battery for storing power supplied from the charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; and a second power system for supplying power from the charger to the electric motor without going through the battery, the control method comprising: obtaining the vehicle's power consumption, including the power consumption of the electric motor of the work vehicle; and causing the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle's power consumption.

12. A computer program used to control the power supply from a charger to an electric work vehicle, wherein the work vehicle comprises: a charging inlet; a battery that stores power supplied from the charger through the charging inlet; an electric motor that operates on power supplied from the battery; a first power system for supplying power from the charger to the battery; and a second power system for supplying power from the charger to the electric motor without going through the battery, and the computer program causes a computer to perform the following actions: obtain the vehicle power consumption, including the power consumption of the electric motor of the work vehicle; and cause the charger to limit the output current according to the result of comparing the upper limit output of the charger with the vehicle power consumption.

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