METHOD AND SYSTEM FOR REGULATING POWER DISTRIBUTED IN AN ELECTRIC AGRICULTURAL TRACTOR

Abstract

METHOD AND SYSTEM FOR REGULATING POWER DISTRIBUTED IN AN ELECTRIC AGRICULTURAL TRACTOR The invention relates to a system for regulating the electrical power supplied by an electrical energy storage device (102) to at least two electrical energy-consuming devices (106, 110, 112a, 114, 116, 122) of an electric agricultural tractor, comprising a comparison of the electrical power supplied with a maximum deliverable power threshold, and if the electrical power supplied reaches or exceeds said threshold, a reduction in the power distributed to at least one consuming device, each consuming device being associated with a unique priority value, including, if a consuming device is associated with the lowest priority value,or if a consuming device is not associated with the lowest priority value and if all consuming devices with a lower priority value have reached a minimum threshold of received power, a decrease in the electrical power supplied to that consuming device. Figure for the abbreviation: Figure 2,

Description

Title of the invention: METHOD AND SYSTEM FOR REGULATING DISTRIBUTED POWER IN AN ELECTRIC AGRICULTURAL TRACTOR Technical field of the invention

[0001] The invention relates to a method and a system for regulating distributed power in an electric agricultural tractor. More particularly, the invention relates to a method and a system for regulating the electrical power distributed to energy-consuming devices, according to a priority assigned to each of these energy-consuming devices. Technological background

[0002] In an agricultural context where field work has been greatly facilitated by the development of agricultural machinery, the use of thermal agricultural tractors, widely acclaimed by farmers, will now have to face the challenge of ecological transition.

[0003] More environmentally friendly approaches tend to move away from the use of fossil fuels as the sole source of fuel; we are seeing more and more agricultural machinery with hybrid technology combining fossil fuels and electrical power.

[0004] Most of these machines use a chassis with a classic load-bearing structure incorporating the "thermal engine - transmission shaft - gearbox" triad which has proven itself for more than a century.

[0005] Some agricultural concepts have been developed around fully electric operation. The vehicle is then powered by a battery attached to the tractor or by an additional structure installed on the latter. The thermal engine is thus replaced by an electric motor and a battery.

[0006] In a tractor equipped with a thermal engine, the mechanical power is generated by a single source and the distribution of this power is done naturally. All consumers are mechanically connected to each other.

[0007] In the case of an electric tractor, each mechanical power consumer can be supplied by an individual source.

[0008] The energy demand of a fully electric agricultural tractor therefore remains a limiting factor and the regulation of the electrical power supplied by the battery is essential. The objective is in particular not to exceed the maximum power available at the battery output, to ensure that no element is in an overload condition, and to allow the tractor operator to define the elements having priority over electrical power consumption.

[0009] Another solution proposed in the state of the art consists mainly of implementing a generalized reduction of the electrical power distributed to each energy consuming device, proportionally to their individual maximum power level and to the power limit available at the battery output.

[0010] This solution does not allow for overall power management, which can lead to situations in which certain elements are overloaded while others are not used to their maximum capacity. In addition, this solution tends to quickly limit the devices in the mechanical power chain, which can therefore rarely be used to their maximum capacity.

[0011] Another solution is to size the electrical system, in particular the battery, so that it is able to accept almost all of the cumulative power consumed by the energy-consuming devices.

[0012] This solution results in an oversizing of the electrical system relative to its average use, which leads to additional constraints, in particular on the size, weight and cost of the battery device.

[0013] The inventors therefore sought to provide a solution to overcome these drawbacks. Objectives of the invention

[0014] The invention aims to provide a method and system for regulating the electrical power supplied to the electrical energy consuming devices of an electric agricultural tractor.

[0015] The invention also aims to provide, in at least one embodiment, a method and system for regulating electrical power making it possible to prioritize energy-consuming devices according to their criticality and the actions implemented by the electric agricultural tractor.

[0016] The invention also aims to provide, in at least one embodiment, a method and system for regulating electrical power making it possible to maximize the use of the power produced by the electrical energy storage device.

[0017] The invention also aims to provide, in at least one embodiment, a method and system for regulating electrical power making it possible to avoid oversizing the electrical energy storage device.

[0018] The invention also aims to provide, in at least one embodiment, a method and system for regulating electrical power making it possible to provide an agricultural operator with a full working day in the same way as a thermal agricultural tractor of the same range would. Statement of the invention

[0019] To this end, the invention relates to a method for regulating the electrical power supplied by an electrical energy storage device to at least two electrical energy consuming devices of an electric agricultural tractor comprising a step of comparing the electrical power supplied by the storage device with a maximum deliverable power threshold, and if the electrical power supplied reaches or exceeds said maximum threshold, a step of reducing the power distributed to at least one energy consuming device, each energy consuming device being associated with a unique priority value for energy consumption, comprising: if an energy consuming device is associated with the lowest priority value among the energy consuming devices, a sub-step of decreasing the electrical power supplied to this energy consuming device, if an energy consuming device is not associated with the lowest priority value, and if all energy consuming devices with a lower priority value have reached a minimum threshold of received power, a sub-step of reducing the electrical power supplied to this energy consuming device.

[0020] A method for regulating electrical power according to the invention therefore allows the prioritization of energy consuming devices if the total power consumed is too high and thus to use each consuming device to its maximum potential without requiring oversizing of the battery in average use. The reduction of the distributed power thus applies only to the energy consuming device considered to be the lowest priority. If the power supplied to this lowest priority device reaches a minimum necessary for its operation, the device placed high above it in the priority list is also limited in its energy consumption, and so on for each energy consuming device as classified in the priority list. The devices are thus classified according to a priority chain.

[0021] The priority parameters and their ranking may for example be predetermined by the manufacturer of the electric agricultural tractor and / or may be determined by the operator, before or during use of the electric agricultural tractor.

[0022] Throughout the disclosure of the invention, the terms "tractor" and "agricultural tractor" must be interpreted in an equivalent manner and all relate, unless explicitly stated otherwise, to an agricultural work machine intended primarily for transport and traction, as well as for working the soil.

[0023] The electrical energy storage device preferably designates a battery, but can also be a fuel cell, a supercapacitor, a flywheel inertia, etc.

[0024] Advantageously and according to the invention, the maximum deliverable power threshold is substantially equal to the maximum power that the electrical energy storage device can deliver.

[0025] According to this aspect of the invention, the power threshold is sufficiently close to the maximum power that the electrical energy storage device can deliver to maximize the power available to the energy consuming devices.

[0026] Advantageously and according to the invention, the following priority values ​​are assigned to at least the following energy-consuming devices of the electric agricultural tractor: - a highest priority value associated with a DC / DC electrical converter configured for conversion of electrical energy supplied by the energy storage device for controlling distribution to energy consuming devices and powering the safety systems of the agricultural tractor, - a priority value lower than that of the DC / DC electric converter associated with a thermal management system configured for cooling the components of the agricultural electric tractor, - a priority value lower than that of the thermal management system associated with a hydraulic motor pump unit configured to supply a hydraulic circuit of the electric agricultural tractor, - a priority value lower than that of the hydraulic motor pump unit associated with an air compressor configured to supply a pneumatic circuit of the electric agricultural tractor, - a priority value lower than that of the air compressor associated with at least one power take-off configured to transmit mechanical energy to an accessory tool of the electric agricultural tractor, - a priority value lower than that of each power take-off associated with a traction unit of the electric agricultural tractor configured to allow the movement of the electric agricultural tractor.

[0027] According to this aspect of the invention, these particular priorities are assigned to these particular energy-consuming devices of the electric agricultural tractor, so as to correspond to their criticality in the operation of the agricultural tractor while remaining representative of a conventional use of the agricultural tractor. These devices are also the most electrically energy-consuming, in comparison with other ancillary energy-consuming devices such as lighting devices whose necessary electrical power is relatively low compared to the devices in this list.

[0028] In particular, the DC / DC electrical converter (frequently called DC / DC converter) allows the transformation of the electric current coming from the energy storage device for the control of the distribution to the energy consuming devices and the power supply of the safety systems of the agricultural tractor and its function is therefore the most critical. In particular, it allows the power supply of the low voltage network of the electric agricultural tractor which in particular makes it possible to power the computers of the electric agricultural tractor. These computers ensure in particular the control of the electrical distribution to the energy consuming devices and the management of safety functions such as the control of traction, braking and steering.

[0029] The power take-off(s) and the traction unit can be suspended or temporarily limited in power in the event of a temporary overload of the power consumed.

[0030] The power take-off is also called power take-off or abbreviated as PTO for “Power Take-Off” in English.

[0031] The accessory tool is in particular a tool attached to the electric agricultural tractor, and connected to the power take-off to ensure at least one of its functions.

[0032] Advantageously and according to the invention, the method comprises a step of modification by the operator of the agricultural tractor of one, several or all of the priority values ​​associated with the energy consuming devices.

[0033] According to this aspect of the invention, the priority values ​​of the components can be modified by the operator of the agricultural tractor to enable him to adapt the priorities, for example, depending on the accessory tool(s) attached to the power take-off(s), the physical situation of the electric agricultural tractor (land used, etc.), the actions to be implemented, the electrical energy still available, etc.

[0034] In particular, the operator can advantageously choose to define a priority between traction and power take-off in the event that one of its devices is in an overload situation. The speed of one impacts the power consumed by the other, the element with the lowest priority will slow down by a certain percentage so as to reduce the power consumed by the other.

[0035] The invention also relates to a system for regulating the electrical power supplied by an electrical energy storage device to at least two electrical energy consuming devices of an electric agricultural tractor comprising a circuit for controlling the power supplied to each energy consuming device, a module for comparing a signal representative of the electrical power supplied by the storage device with a maximum deliverable power threshold, a module for transmitting a signal for reducing the distributed power if the electrical power supplied reaches or exceeds the maximum threshold, each device energy consumer being associated with a unique priority value for energy consumption, a control loop comprising a module for receiving the power reduction signal, and a module for determining the power reduction for each energy storage device, configured For : - if the energy device is associated with the lowest priority value among the energy consuming devices, sending to the control circuit a signal to reduce the electrical power supplied to this energy consuming device, - if the energy consuming device is not associated with the lowest priority value, and if all the energy consuming devices with a lower priority value have reached a minimum threshold of received power, sending to the control circuit a signal to reduce the electrical power supplied to this energy consuming device.

[0036] The electrical power regulation system according to the invention is advantageously configured to implement the electrical power regulation method according to the invention.

[0037] The method for regulating electrical power according to the invention is advantageously configured to be implemented by the electrical power regulation system according to the invention.

[0038] The advantages of the method for regulating electrical power according to the invention apply mutatis mutandis to the system for regulating electrical power according to the invention.

[0039] Advantageously and according to the invention, the maximum deliverable power threshold is substantially equal to the maximum power that the electrical energy storage device can deliver.

[0040] Advantageously and according to the invention, the system is configured for regulating the electrical power supplied to the following electrical energy consuming devices of the electric agricultural tractor: - a DC / DC electrical converter, associated with a highest priority value, and configured for conversion of the electrical energy supplied by the energy storage device for controlling the distribution to the energy consuming devices and supplying the safety systems of the agricultural tractor, - a thermal management system, associated with a priority value lower than the DC / DC electric converter, and configured for cooling the components of the agricultural electric tractor, - a hydraulic motor pump group, associated with a lower priority value to the thermal management system, and configured to supply a hydraulic circuit of the electric agricultural tractor, - an air compressor, associated with a priority value lower than the hydraulic motor pump unit, and configured to supply a pneumatic circuit of the electric agricultural tractor, - at least one power take-off, associated with a priority value lower than the air compressor, and configured to transmit mechanical energy to an accessory tool of the electric agricultural tractor, - a traction group of the electric agricultural tractor, associated with a priority value lower than each power take-off, and configured to allow the movement of the electric agricultural tractor.

[0041] Advantageously and according to the invention, the regulation system comprises means for modification by the operator of the agricultural tractor of one, several or all of the priority values ​​associated with the energy consuming devices.

[0042] The invention also relates to an electric agricultural tractor comprising an electrical energy storage device and at least two electrical energy consuming devices, characterized in that it comprises an electrical power regulation system according to the invention, configured for regulating the electrical power delivered by the electrical energy storage device to each electrical energy consuming device.

[0043] The invention also relates to a method for regulating electrical power, an electrical power regulation system and an electric tractor characterized in combination by all or part of the characteristics mentioned above or below. List of figures

[0044] Other aims, characteristics and advantages of the invention will appear on reading the following description given solely for non-limiting purposes and which refers to the appended figures in which: • [Fig.l] is a schematic view representing an electrical circuit of an electric agricultural tractor configured to implement a method for regulating the electrical power according to one embodiment of the invention. • [Fig.2] is a schematic view representing a control loop represented representative of the method for regulating electrical power according to an embodiment of the invention.

[0045] Detailed description of an embodiment of the invention

[0046] In the figures, the scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0047] Identical, similar or analogous elements are designated by the same references in all the figures.

[0048] [Fig.l] schematically represents an electrical circuit 100 of an electric agricultural tractor configured to implement a method for regulating the electrical power according to an embodiment of the invention. The electrical circuit 100 is also capable of being regulated by a regulation system according to an embodiment of the invention.

[0049] The electrical circuit 100 comprises an energy storage device, here a battery 102 supplying a high voltage direct current bus 104, allowing the distribution of electrical energy to the energy consuming devices, in particular: - to a DC / DC converter 106 configured for conversion of the electrical energy supplied by the energy storage device for controlling the distribution to the energy consuming devices and powering the safety systems of the agricultural tractor, supplying a low voltage circuit 108, - to a thermal management system 110 configured for cooling the components of the agricultural electric tractor, in particular other energy-consuming devices, - to a hydraulic system 112 configured for supply by a hydraulic motor pump group 112a of a hydraulic circuit 112b of the electric agricultural tractor, - to an air compressor 114 configured to supply a pneumatic circuit of the electric agricultural tractor, - at least one power take-off, here a power take-off 116 driven via an electric motor 118 of a power take-off group 120, configured to transmit mechanical energy to an accessory tool of the electric agricultural tractor, - to a traction group 122, comprising a first electric traction motor 124a associated with a first axle 126a and a second electric traction motor 124b associated with a first axle 126b.

[0050] [Fig. 2] schematically represents a control loop 200 representative of the method for regulating the electrical power according to an embodiment of the invention. The control loop 200 receives information from the electrical circuit 100 as described previously and sends control signals allowing the regulation of the distribution of the electrical power. In particular, the control loop 200 receives from the electrical circuit 100 a first signal 202 representative of the maximum threshold of power deliverable by the battery, and a second signal 204 representative of the electrical power supplied by the battery.

[0051] These two signals are compared in a comparator 206 of the control loop, and the signal 208 representative of the comparison is transmitted to a regulator 210, preferably a PID regulator.

[0052] The control signal from the regulator 210 is transferred to regulation modules associated with each power consuming device. This control signal is representative of the reduction in consumed power required for all of the power consuming devices. A first regulation module 220 is dedicated to the traction unit, a second regulation module 222 is dedicated to the power take-off, a third regulation module 224 is dedicated to the air compressor, a fourth regulation module 226 is dedicated to the hydraulic motor pump unit, a fifth regulation module 228 is dedicated to the thermal management system and a sixth regulation module 230 is dedicated to the DC / DC converter.

[0053] From the first regulation module to the fifth regulation module, the regulation modules each comprise an output “2” indicating to the higher priority regulation module that the minimum power allocated to this energy consuming device has been reached. Each regulation module then sends its delivered power reduction instruction associated with the energy consuming device to a bus 232, which transmits these signals to the control circuit 100.

[0054] In particular, when the regulator 210 sends a signal indicating a power reduction instruction, the first regulation module 220 sends a first power reduction instruction 220b to the bus 232.

[0055] If a minimum power threshold of the energy consuming device associated with the first regulation module 220 is reached, the first regulation module 220 sends a signal 220a to the second regulation module 222, to indicate that the associated energy consuming device must reduce its consumed power in turn. The second regulation module 222 then sends a second power reduction instruction 222b to the bus 232.

[0056] If a minimum power threshold of the energy consuming device associated with the second regulation module 222 is reached, the second regulation module 222 sends a signal 222a to the third regulation module 224, to indicate that the associated energy consuming device must reduce its consumed power in turn. The third regulation module 224 then sends a third power reduction instruction 224b to the bus 232.

[0057] If a minimum power threshold of the energy consuming device associated with the third regulation module 224 is reached, the third regulation module 224 sends a signal 224a to the fourth regulation module 226, to indicate that the associated energy-consuming device must reduce its power consumption in turn. The fourth regulation module 226 then sends a fourth power reduction instruction 226b to the bus 232.

[0058] If a minimum power threshold of the energy consuming device associated with the fourth regulation module 226 is reached, the fourth regulation module 226 sends a signal 226a to the fifth regulation module 228, to indicate that the associated energy consuming device must reduce its consumed power in turn. The fifth regulation module 228 then sends a fifth power reduction instruction 228b to the bus 232.

[0059] If a minimum power threshold of the energy consuming device associated with the fifth regulation module 228 is reached, the fifth regulation module 228 sends a signal 228a to the sixth regulation module 230, to indicate that the associated energy consuming device must reduce its consumed power in turn. The sixth regulation module 230 then sends a sixth power reduction instruction 230b to the bus 232.

[0060] The number of energy-consuming devices and therefore the number of associated regulation modules can vary depending on the electric agricultural tractor, and the control loop is adapted accordingly.

[0061] The described control loop is one embodiment and other variants of the invention are possible. For example: - each regulation module can have its own internal regulator to manage the power reduction setpoint, - the reduction control signal may only be transmitted to the first regulation module, the latter transmitting a new control signal to the higher priority regulation module if its minimum power threshold is reached, and so on from one regulation module to the higher priority regulation module in the priority chain, - the signal representing the electrical power supplied by the battery can be replaced by a calculation of the sum of the powers received by each energy consuming device, and for example calculated by each regulation module for its associated energy consuming device, - the power drop rate can be calculated at the loop level or by the control circuit.

Claims

Claims

1. Method for regulating the electrical power supplied by an electrical energy storage device (102) to at least two electrical energy consuming devices (106, 110, 112a, 114, 116, 122) of an electric agricultural tractor comprising a step of comparing the electrical power supplied by the storage device (102) with a maximum deliverable power threshold, and if the supplied electrical power reaches or exceeds said maximum threshold, a step of reducing the power distributed to at least one energy consuming device (106, 110, 112a, 114, 116, 122), each energy consuming device (106, 110, 112a, 114, 116, 122) being associated with a unique priority value for energy consumption, comprising: • if a device (106, 110, 112a, 114, 116, 122) energy consumer is associated with the lowest priority value among the energy consuming devices,a sub-step of reducing the electrical power supplied to this energy consuming device, • if an energy consuming device (106, 110, 112a, 114, 116, 122) is not associated with the lowest priority value, and if all of the energy consuming devices with a lower priority value have reached a minimum threshold of received power, a sub-step of reducing the electrical power supplied to this energy consuming device.,

2. Method for regulating electrical power according to claim 1, characterized in that the maximum deliverable power threshold is substantially equal to the maximum power that the electrical energy storage device (102) can deliver.

3. Method for regulating electrical power according to one of claims 1 or 2, characterized in that the following priority values ​​are assigned to at least the following energy consuming devices of the electric agricultural tractor: • a highest priority value associated with a DC / DC electrical converter (106) configured for conversion of the electrical energy supplied by the energy storage device (102) for distribution control to the energy-consuming devices and the power supply of the safety systems of the agricultural tractor, • a priority value lower than that of the DC / DC electric converter (106) associated with a thermal management system (110) configured for cooling the components of the electric agricultural tractor, • a priority value lower than that of the thermal management system (110) associated with a hydraulic motor pump group (112a) configured for supplying a hydraulic circuit (112b) of the electric agricultural tractor, • a priority value lower than that of the hydraulic motor pump group (112a) associated with an air compressor (114) configured for supplying a pneumatic circuit of the electric agricultural tractor,• a priority value lower than that of the air compressor (114) associated with at least one power take-off (116) configured to transmit mechanical energy to an accessory tool of the electric agricultural tractor, • a priority value lower than that of each power take-off (116) associated with a traction group (122) of the electric agricultural tractor configured to allow the movement of the electric agricultural tractor.,

4. Method for regulating electrical power according to one of claims 1 to 3, characterized in that it comprises a step of modification by the operator of the agricultural tractor of one, several or all of the priority values ​​associated with the energy-consuming devices (106, 110, 112a, 114, 116, 122).

5. System for regulating the electrical power supplied by an electrical energy storage device to at least two electrical energy consuming devices (106, 110, 112a, 114, 116, 122) of an electric agricultural tractor comprising a circuit for controlling the power supplied to each energy consuming device (106, 110, 112a, 114, 116, 122), a module (206) for comparing a signal representative of the electrical power supplied by the storage device with a maximum deliverable power threshold, a module for transmitting a signal for reducing the distributed power if the supplied electrical power reaches or exceeds the maximum threshold, each energy consuming device (106, 110, 112a, 114, 116, 122) being associated with a unique priority value for energy consumption, a regulation loop (200) comprising a module for receiving the power reduction signal, and a module for determining the power reduction for each energy storage device, configured to: • if the energy device is associated with the lowest priority value among the energy consuming devices, sending to the control circuit a signal (220b) for reducing the electrical power supplied to this energy consuming device, • if the energy consuming device is not associated with the lowest priority value, and if all the energy consuming devices with a lower priority value have reached a minimum threshold of received power,sending to the control circuit a signal (222b, 224b, 226b, 228b, 230b) reducing the electrical power supplied to this energy-consuming device.,

6. Electrical power regulation system according to claim 5, characterized in that the maximum deliverable power threshold is substantially equal to the maximum power that the electrical energy storage device can deliver.

7. Electrical power regulation system according to one of claims 5 or 6, characterized in that it is configured for the regulation of the electrical power supplied to the following electrical energy consuming devices of the electric agricultural tractor: • a DC / DC electrical converter (106), associated with a highest priority value, and configured for a conversion of the electrical energy supplied by the energy storage device (102) for the control of the distribution to the energy consuming devices and the supply of the safety systems of the agricultural tractor, • a thermal management system (110), associated with a priority value lower than the DC / DC electrical converter (106), and configured for cooling of the components of the electric agricultural tractor, • a hydraulic motor pump group (112a), associated with a priority value lower than the thermal management system (110), and configured for supplying a hydraulic circuit (112b) of the electric agricultural tractor, • an air compressor (114), associated with a priority value lower than the hydraulic motor pump group (112a), and configured for supplying a pneumatic circuit of the electric agricultural tractor, • at least one power take-off (116), associated with a priority value lower than the air compressor (114), and configured to transmit mechanical energy to an accessory tool of the electric agricultural tractor, • a traction group (122) of the electric agricultural tractor, associated with a priority value lower than each power take-off (116), and configured to allow the movement of the electric agricultural tractor.

8. Electrical power regulation system according to one of claims 5 to 7, characterized in that it comprises means for modification by the operator of the agricultural tractor of one, several or all of the priority values ​​associated with the energy-consuming devices (106, 110, 112a, 114, 116, 122).

9. Electric agricultural tractor comprising an electrical energy storage device (102) and at least two electrical energy consuming devices (106, 110, 112a, 114, 116, 122), characterized in that it comprises an electrical power regulation system according to one of claims 5 to 8, configured for regulating the electrical power delivered by the electrical energy storage device (102) to each electrical energy consuming device (106, 110, 112a, 114, 116, 122).

Images