Method and system for controlling traction speed of mining vehicle during downhill travel

Abstract

A computer-implemented method for controlling the traction speed of a mining vehicle during downhill travel is disclosed. A mining vehicle includes a traction control system, an electric drive system including a traction engine and at least one inverter, and an electrical energy storage. The method includes: setting a braking torque of the traction engine and determining an available charging power of the electrical energy storage; calculating a reference speed of the traction engine based on the available charging power and the set brake torque when the available charging power is lower than a first predetermined value; and controlling the traction speed of the mining vehicle by controlling the speed of the traction engine to the reference speed.

Description

Technical Field

[0001] The present disclosure generally relates to electrically driven mining vehicles. In particular, the present disclosure relates to methods and systems for controlling the traction speed of an electric mining vehicle during downhill travel. Background Art

[0002] When an electric vehicle moves downhill, the electric motor acts as a generator, converting the kinetic energy from the vehicle into electrical energy while decelerating the vehicle. The electrical energy can be used to charge the vehicle's battery. This is known as regenerative braking. Thus, regenerative braking is a form of engine braking unique to electric vehicles.

[0003] One advantage of regenerative braking is that it limits the reliance on traditional friction braking. Friction braking is associated with several problems, one of which is overheating. Overheating is particularly dangerous in mining environments where service is not readily available.

[0004] During regenerative braking, the battery can only receive the generated electrical energy until it is fully charged. Thus, one problem associated with regenerative braking is that when the battery is fully charged, the electric vehicle may lose its engine braking ability because the battery can no longer receive charge. In mining environments, mining vehicles often travel long distances downhill, resulting in a large amount of regenerative energy. In fact, it is not uncommon for a mining vehicle to have a fully charged battery when it reaches the lower end of the mine. This poses a risk because the vehicle will rely solely on friction braking during at least a portion of the downhill travel.

[0005] Another problem during downhill travel is overspeed. Overspeed refers to a state where the engine speed of the vehicle is forced to reach beyond the design limits of the vehicle, which can cause damage to the vehicle. The risk of entering the overspeed state increases when the vehicle battery becomes fully charged and the ability of engine braking is unavailable.

[0006] Therefore, there is a need for a solution for sustainable regenerative braking of mining vehicles, i.e., a solution that can also be used after a mining vehicle travels downhill for a long time. Summary of the Invention

[0007] The object of the present disclosure is to overcome at least some of the above problems and provide a solution for controlling the speed of a mining vehicle in order to maintain regenerative braking.

[0008] This object and other objects are achieved by a computer-implemented method, a computer program product, a traction control system, and a mining vehicle defined in the appended claims. In this context, the term "exemplary" should be understood as being used as an instance, example, or illustration.

[0009] In a first aspect of the present disclosure, there is provided a computer-implemented method for controlling the traction speed of a mining vehicle during downhill travel. The mining vehicle includes a traction control system, an electric drive system including a traction engine and at least one inverter, and an electrical energy storage. The method includes: setting a braking torque of the traction engine and determining available charging power of the electrical energy storage; when the available charging power is below a first predetermined value, calculating a reference speed of the traction engine based on the available charging power and the set braking torque; and controlling the traction speed of the mining vehicle by controlling the speed of the traction engine to the reference speed.

[0010] Controlling the traction speed to the reference speed allows the vehicle to decelerate during downhill travel without exceeding the available power of the battery (i.e., the power that the battery can receive before being fully charged). Thus, the level of the set engine braking is always available without exceeding the available power of the battery and can avoid overspeeding.

[0011] The reference speed is the calculated speed. Specifically, the reference speed is calculated such that: if the speed of the traction engine is controlled to the reference speed, the set engine braking is maintained and the battery is not charged to an undesired level. The undesired level is associated with the battery being fully charged or nearly fully charged.

[0012] In some examples, controlling the speed includes controlling the output DC of at least one inverter.

[0013] When the electric motor generates electricity, the magnetic field in the electric motor causes the electric motor to decelerate. Thus, by controlling the output DC of at least one inverter, it is possible to control how much electricity is generated in the electric motor and thus how much the magnetic field causes the electric motor to decelerate. Using the existing components of the electric motor in the vehicle to control the speed and thus the traction speed is efficient and economical. In addition, controlling the speed by controlling the output DC is a method of providing high precision and control over the final traction speed.

[0014] In some examples, the speed of the traction engine is not allowed to exceed the reference speed.

[0015] Thus, the speed is maintained at a level where the set engine braking is maintained and thereby the available charging power is maintained below the predetermined value.

[0016] In some examples, determining the available charging power includes requesting the available charging power from the battery management system (BMS) of the mining vehicle. Utilizing the existing systems of the vehicle (such as the BMS) is efficient and economical.

[0017] In some examples, the available charging power is obtained from the BMS at scheduled and / or regular intervals. In some examples, when it is determined that the vehicle is traveling downhill, the available charging power is obtained from the BMS at a predetermined time interval.

[0018] In some examples, the available charging power is based on at least one of the state of charge (SoC) of the electrical energy storage and the temperature of the electrical energy storage. Both the SoC and the temperature provide information on how much power the battery can receive.

[0019] In some examples, the method may include determining the inclination of the ground at the location of the mining vehicle; and calculating a braking torque based on the determined inclination of the ground. This allows adapting the reference speed depending on the location of the vehicle and on the characteristics of the vehicle's surroundings. This provides a higher level of control and more efficient energy utilization.

[0020] In some examples, the location of the mining vehicle is one of the current location or an expected future location along the travel route of the mining vehicle. This allows the reference speed to be adapted not only depending on the current location, but also to be such that the appropriate reference speed to be set has been determined by the time the vehicle reaches a downhill slope.

[0021] In some examples, determining the inclination includes: obtaining data from a positioning system, the data including information on the inclination of the ground at the location of the mining vehicle.

[0022] Positioning systems in mining environments are generally able to determine the position of objects in the mining environment with high precision. Thus, these systems can be used to provide information related to the position of the vehicle. The information can be provided to the vehicle from a remote system or from the vehicle to a remote system.

[0023] In some examples, the mining vehicle includes at least two gears, and the method may include: determining which one of the at least two gears is engaged; and setting a braking torque based on the determination. In some examples, the method may include: preventing a shift to a higher gear when the available charging power is below a second predetermined value that is lower than a first predetermined value.

[0024] The system may be arranged to prevent the vehicle from reaching an undesirable state, such as a state where engine braking is unavailable.

[0025] Preventing a shift to a higher gear may include, for example, mechanically preventing the shift or communicating an alert to the driver that the shift is not recommended.

[0026] In a second aspect of the present disclosure, there is provided a computer program including instructions which, when executed by a computer, cause the computer to implement the method according to the first aspect.

[0027] In a third aspect of the present disclosure, there is provided a computer-readable medium including instructions which, when executed by a computer, cause the computer to implement the method according to the first aspect.

[0028] In a fourth aspect of the present disclosure, there is provided a traction control system for controlling the traction speed of a mining vehicle during downhill travel. The mining vehicle includes an electric drive system and an electrical energy storage, and the electric drive system includes a traction motor and at least one inverter. The traction control system includes means for communicating with the electric drive system, a processing circuit, and a memory, wherein the memory includes instructions executable by the processing circuit. The traction control system is operable to set a braking torque of the traction motor and determine available charging power of the electrical energy storage. When the available charging power is below a first predetermined value, the traction control system is further operable to calculate a reference speed of the traction motor based on the available charging power and the set braking torque, and control the traction speed of the mining vehicle by controlling the speed of the traction motor to the reference speed.

[0029] In a fifth aspect of the present disclosure, there is provided a mining vehicle including: the traction control system according to the fourth aspect, an electric drive system including a traction motor and at least one inverter, and an electrical energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present disclosure will now be described by way of example with reference to the accompanying drawings, in which:

[0031] Figure 1 An example mining vehicle during downhill travel is shown.

[0032] Figure 2 An example electric drive system and vehicle components are shown.

[0033] Figure 3 An example traction control system is shown.

[0034] Figure 4 An example method for speed control is shown. DETAILED DESCRIPTION

[0035] In the following, a detailed description of a computer-implemented method, system, computer program, computer-readable medium, and mining vehicle is provided. In the drawings, throughout the drawings, like reference numerals refer to like or corresponding elements. Optional features are shown with dashed lines. It will be understood that these figures are for illustration only and do not limit the scope of the present disclosure in any way.

[0036] Reference Figure 1 , vehicle 10 is shown. Vehicle 10 is a mining vehicle 10 arranged to travel in a mining environment. The mining environment can be, but is not limited to, an underground mine or an open-pit mine, such as open-pit mining. The mining environment can be an area adjacent to or connected to a mine. Thus, the mining environment can be regarded as any area where a mining vehicle can travel normally during operation. Figure 1The vehicle 10 therein is illustrated as a loader. The loader is arranged to load blasted rock onto a mining truck at a blasting site. For this purpose, the loader includes a bucket 11 into which the blasted rock can be loaded and subsequently emptied, for example, into a mining truck. In an alternative embodiment, the vehicle 10 can also be illustrated as a mining truck, which is arranged to transport the blasted rock through a mining environment from a blasting site. The vehicle 10 can be operated by an operator sitting inside the vehicle 10, by a remote operator, or autonomously. It will be understood that the exemplary mining vehicle 10 is not a limitation on the scope of the present disclosure, and the present disclosure encompasses other types of mining vehicles. Examples of mining vehicles include loaders, dump trucks, trucks, excavators, drills, and transporters.

[0037] The mining vehicle 10 is driven by an electric drive system 20. Turning Figure 2 , the electric drive system 20 generally includes a traction motor 21 and an inverter 22. One end of the electric drive system 20 is connected to a battery 30 via the inverter 22, and the other end is connected to a gearbox 40.

[0038] Returning to Figure 1 the downhill scenario, when traveling within a mining environment, the mining vehicle 10 may travel downhill for long distances. The mining vehicle must always maintain its braking ability and be able to stop completely when required. For this purpose, the vehicle 10 includes friction brakes and also has the ability to perform engine braking. A well-known drawback of using friction brakes to decelerate the vehicle 10 is the risk of overheating. Therefore, engine braking is preferably used. The reliability of the braking system of the vehicle 10 is crucial, not only for safe operation but also because access to service and maintenance may be restricted in some mining environments.

[0039] Engine braking by means of regenerative braking results in a charging operation performed by the electric drive system, i.e., charging the battery 30 connected to the electric drive system 20. When the mining vehicle 10 moves downhill, the electric drive system 20 acts as a generator, and the electricity generated can be used to charge the vehicle battery. An important aspect to consider regarding regenerative braking is that it is only available when the battery is not fully charged.

[0040] The ability of the vehicle 10 to perform engine braking depends on the braking torque. The theoretical braking torque required to keep the vehicle 10 stationary is related to the slope α of the downhill. The greater the slope α, the greater the component of the gravitational vector and thus the greater the gravitational force acting on the vehicle 10, and hence the greater the torque. The smaller the slope α, the smaller the torque.

[0041] Figure 2Shows the electric drive system 20 of the mining vehicle 10. The electric drive system 20 generally includes a traction engine 21 and an inverter 22. One end of the electric drive system 20 is connected to the battery 30 via the inverter 22, and the other end is connected to the gearbox 40. According to Figure 2 The gearbox includes a first gear and a second gear 42, and the gearbox is then connected to at least one axle 50, on which two wheels 51 are arranged.

[0042] In an alternative embodiment, instead, the electric drive system 20 is directly (or via a suitable connecting device) connected to at least one axle 50, that is, the disclosed gearbox 40 is not included.

[0043] The battery 30 is arranged to store electrical energy for driving the vehicle 10. The power output from the battery 30 is direct current (DC). The inverter 22 converts the DC into alternating current (AC) for driving the traction engine 21. The inverter 22 also controls the output frequency of the alternating current. A high output frequency results in a high rotational speed of the traction engine 21. The rotational speed is the speed at which the rotor of the traction engine rotates. The rotational speed can be measured in revolutions per minute (rpm). When the rotational speed increases, the traction speed of the vehicle 10 increases. The traction speed is defined as the speed at which the mining vehicle (e.g., on the roads in a mining environment) travels. The traction speed can be measured, for example, in kilometers per hour (km / h) or miles per hour. Conversely, a low output frequency results in a low rotational speed and the vehicle 10 decelerates. However, during downhill travel, due to gravity, the rotational speed of the traction engine 21 is maintained or increased without an energy input from the battery 30. This enables the traction engine 21 to perform engine braking through regenerative braking. For this purpose, the inverter 22 is also capable of converting the input AC from the traction engine 21 into output DC to charge the battery 30.

[0044] The traction speed affects how much power the traction engine can generate during downhill travel. The higher the traction speed of the mining vehicle 10, the more power needs to be generated in the traction engine in order to decelerate the vehicle. Therefore, it would be an advantage if the traction speed of the mining vehicle is maintained below a level at which it is not possible to decelerate the vehicle without fully charging the battery.

[0045] Reference Figure 3 Shows a traction control system 60. The traction control system 60 generally includes a communication device 61, a processing circuit 62, and a memory 63. In Figure 3 Also shown is a computer program 70 including instructions that, when executed by a computer, cause the computer to implement a method 80 according to the present disclosure.

[0046] The traction control system 60 is arranged to control the traction speed of the vehicle 10. To this end, the traction control system 60 is arranged to control the amount of regenerative power used to charge the battery 30, thus ensuring that sufficient engine braking torque is always available.

[0047] The traction control system 60 communicates with the electric drive system 20 via the communication device 61. The traction control system 60 communicates with the inverter 22 to control the inverter 22. The traction control system 60 can control the output of the inverter 22. The traction control system 60 can control the output DC from the inverter 22 to the battery 30. The traction control system 60 can control the output frequency from the inverter 22 to the traction engine 21.

[0048] The traction control system 60 also communicates with the battery management system (BMS) of the vehicle 10 via the communication device 61. The traction control system 60 can obtain information about the battery 30 from the BMS. Such information can be, for example, the available charging power. The available charging power is defined as the ability of the battery 30 to receive charging power and depends on both the state of charge (SoC) of the battery 30 and the temperature of the battery 30. The higher the SoC, the lower the available charging power. When the battery 30 has a temperature within the optimal temperature range, it means high available charging power. When the temperature is outside the optimal temperature range, it means low available charging power. Specifically, the lower the available charging power, the further the temperature of the battery is from the optimal temperature range. The optimal temperature range can be between 20°C and 40°C. The optimal temperature range can be between 25°C and 35°C. The optimal temperature range can be between 27°C and 35°C.

[0049] Reference Figure 4 Furthermore, a method 80 according to the present disclosure is provided. The method 80 is a computer-implemented method. The method 80 is preferably executed by the traction control system 60 according to the present disclosure.

[0050] Executing the method 80 has the effect of being able to control the traction speed of the vehicle 10 during downhill driving. As described above, one purpose of controlling the traction speed during downhill driving is to control how much power is generated during regenerative braking. By controlling how much power is generated, it is possible to avoid charging the battery 30 to a level where engine braking is unavailable.

[0051] The method 80 includes a step 81 of setting the braking torque. The set braking torque can limit the minimum level of the braking torque below which there is a risk of reduced engine braking availability. The set braking torque can limit the minimum level of the braking torque below which engine braking is unavailable for the vehicle 10. The braking torque can be set to 500 Nm. The braking torque can be set to 200 Nm.

[0052] Method 80 includes the step of determining 82 the available charging power of battery 30. Determining the available charging power may include obtaining the available charging power. Determining the available charging power may include obtaining information about the available charging power. This information may be the SoC of battery 30 and / or the temperature of battery 30. Determining the available charging power may include calculating the available charging power based on the obtained information. The available charging power and / or the relevant information may be obtained from the BMS. The available charging power and / or the relevant information may be obtained by the traction control system 60 from the BMS. The available charging power and / or the relevant information may be obtained by requesting from the BMS. The available charging power and / or the relevant information may be obtained from the BMS at scheduled and / or regular intervals. When it is determined that the vehicle is traveling downhill, the available charging power and / or the relevant information may be obtained from the BMS at a predetermined time interval. The method includes determining whether the available charging power is lower than a first predetermined value. This determination may be performed by the traction control system 60. The first predetermined value may be related to the minimum level of the available charging power, below which engine braking is not available for vehicle 10. The first predetermined value may be related to the minimum level of the available charging power, below which there is a risk of reduced engine braking availability.

[0053] Method 80 includes the step of calculating 83 the reference speed of traction engine 21. Calculating 83 the reference speed may be performed by the traction control system 60. Calculating 83 the reference speed may include obtaining the set braking torque. Calculating 83 the reference speed may include obtaining the determined available charging power. Calculating 83 the reference speed may be based on the available charging power and the set braking torque. Calculating 83 the reference speed may include calculating the speed of the traction engine required to maintain the available charging power and the set braking torque. Calculating 83 the reference speed may include calculating the speed of the traction engine required to maintain the available charging power above a predetermined value and the set braking torque. When determining 82 the available charging power, calculating 83 the reference speed may be performed. When the change in the available charging power exceeds a predetermined value, calculating 83 the reference speed may be performed. To this end, calculating 83 the reference speed may include determining the change in the determined available charging power. When setting 81 the braking torque, calculating 83 the reference speed may be performed. When the set braking torque changes, calculating 83 the reference speed may be performed.

[0054] The reference speed may be calculated by the following formula:

[0055]

[0056] where P is the available charging power in kW, B is the power margin in kW, M is the set braking torque in Nm, and N is the reference speed in km / h.

[0057] The power margin is a safety margin included in the formula that takes into account the uncertainty of the available charging power obtained. The power margin can be 10 kW. The power margin can be 20 kW. The power margin can be set depending on which gear is connected. Additionally, the formula can be used without inputting a power margin (i.e., setting the power margin to zero).

[0058] Method 80 includes the step of controlling 84 the traction speed of the mining vehicle 10 by controlling the rotational speed of the traction engine 21 to a reference speed. Controlling the rotational speed of the traction engine 21 can include controlling the inverter 22. Controlling 84 the traction speed can include controlling the rotational speed of the traction engine 21 not to exceed the reference speed.

[0059] In one example, controlling 84 the traction speed of the mining vehicle 10 by controlling the rotational speed of the traction engine 21 can include: controlling the output DC from the inverter 22 to the battery. Controlling the rotational speed of the traction engine 21 can include: controlling the output DC from the inverter 22 to the battery, which in turn controls the input AC from the traction engine 21 to the inverter 22, and thus controls the rotational speed of the traction engine 21. Controlling the rotational speed of the traction engine 21 can include: limiting the output DC from the inverter 22 to the battery to limit the input AC from the traction engine 21 to the inverter 22, and thus limit the rotational speed of the traction engine 21.

[0060] In another example, controlling 84 the traction speed of the mining vehicle 10 by controlling the rotational speed of the traction engine 21 can include: controlling the output frequency from the inverter to the traction engine 21. Controlling the rotational speed of the traction engine 21 can include: limiting the output frequency from the inverter to the traction engine 21, and thus limiting the rotational speed of the traction engine 21.

[0061] Setting the braking torque 81 can include: determining the inclination of the ground under the vehicle 10 or the inclination of a section of the road in front of the vehicle 10. Setting the braking torque can include: determining that the inclination is higher than a predetermined inclination value. Setting the braking torque can include: determining that the inclination is lower than a predetermined inclination value. Setting the braking torque can include: if the inclination is higher than the predetermined inclination value, setting a higher braking torque value, and if the inclination is lower than the predetermined inclination value, setting a lower braking torque. Determining the inclination can include the step of communicating with a device arranged on the vehicle 10 for determining the inclination. For example, such a device can be a gyroscope. Determining the inclination can include: obtaining the inclination from the device for determining the inclination by requesting the inclination. Obtaining the inclination from the device can be performed by the traction control system 60. Determining the inclination can also include the step of obtaining information about the inclination from the positioning system of the mining environment. The positioning system can be capable of determining the position of the vehicle 10 and transmitting information about the position to the vehicle 10. The information can include the inclination at the position or the inclination of a position in front of the vehicle 10 on the travel route of the vehicle 10.

[0062] Setting the braking torque 81 can include: determining the current gear of the vehicle 10. A higher braking torque can be set when it is determined that a higher gear is engaged, and a lower braking torque can be set when it is determined that a lower gear is engaged. This is because the traction speed of the vehicle 10 is higher when a higher gear is engaged compared to when a lower gear is engaged. When the traction speed is higher, the generated electricity can increase. Therefore, a higher braking torque can be set for a higher gear to control the reference speed and, in turn, control the generated electricity to the battery 30. The higher gear can be the second gear, and the lower gear can be the first gear. The braking torque can be set to 500 Nm. The braking torque can be set to 200 Nm. When the vehicle 10 is in the second gear 42, the braking torque can be set to 500 Nm. When the vehicle 10 is in the first gear 41, the braking torque can be set to 200 Nm. The method can also include determining whether the available charging power is lower than a second predetermined value, the second predetermined value being lower than the first predetermined value. When it is determined that the available charging power is lower than the second predetermined value, the method can include at least one of the following: mechanically and / or electrically preventing a shift to a higher gear, communicating to the vehicle driver that a shift to a higher gear is not recommended, bringing the vehicle to a complete stop, and communicating to the driver that engine braking is unavailable.

[0063] In one example, the method includes: setting a braking torque to 500 Nm; obtaining available charging power, wherein the obtained available charging power is 130 kW; calculating a reference speed according to a formula with a 20 kW power margin, wherein the final reference speed is 2102 rpm; and controlling the speed of the traction engine to the reference speed. According to this example, the final traction speed of the mining vehicle 10 is 10.0 km / h.

[0064] In one example, the method includes: setting a braking torque to 500 Nm; obtaining available charging power, wherein the obtained available charging power is 100 kW; calculating a reference speed according to a formula with a 20 kW power margin, wherein the final reference speed is 1529 rpm; and controlling the speed of the traction engine to the reference speed. According to this example, the final traction speed of the mining vehicle 10 is 7.3 km / h.

[0065] In one example, the method includes: setting a braking torque to 200 Nm; obtaining available charging power, wherein the obtained available charging power is 130 kW; calculating a reference speed according to a formula with a 20 kW power margin, wherein the final reference speed is 5255 rpm; and controlling the speed of the traction engine to the reference speed. According to this example, the final traction speed of the mining vehicle 10 is 25.0 km / h.

[0066] Preferred examples of the method 80 and the system have been disclosed above. However, those skilled in the art will realize that this can vary within the scope of the claims without departing from the inventive concept.

[0067] All the alternative embodiments or parts of the embodiments described above can be freely combined or applied separately from each other without departing from the inventive concept, as long as the combination is not contradictory.

Claims

1. A computer-implemented method (80) for controlling the traction speed of a mining vehicle (10) during downhill travel, wherein the mining vehicle (10) comprises: A traction control system (60), an electric drive system (20) including a traction engine (21) and at least one inverter (22), and an electrical energy storage (30). The method (80) includes: Setting (81) the braking torque of the traction engine (21); Determining (82) the available charging power of the electrical energy storage (30); When the available charging power is lower than a first predetermined value, calculating (83) a reference speed of the traction engine (21) based on the available charging power and the set braking torque; and Controlling (84) the traction speed of the mining vehicle (10) by controlling the speed of the traction engine (21) to the reference speed.

2. The method (80) according to claim 1, wherein, Controlling the speed includes: controlling the output direct current of the at least one inverter (22).

3. The method (80) according to claim 1 or 2, wherein The speed of the traction engine (21) is not allowed to exceed the reference speed.

4. The method (80) according to any one of the preceding claims, wherein, Determining the available charging power includes: requesting the available charging power from a battery management system (BMS) of the mining vehicle (10).

5. The method (80) according to any one of the preceding claims, wherein, The available charging power is based on at least one of a state of charge (SoC) of the electrical energy storage (30) and a temperature of the electrical energy storage (30).

6. The method (80) according to any one of the preceding claims, further comprising: Determining the inclination of the ground at the location of the mining vehicle (10); And Calculating the braking torque based on the determined inclination of the ground.

7. The method (80) according to claim 6, wherein, The location of the mining vehicle (10) is one of a current location and an expected future location along the travel route of the mining vehicle (10).

8. The method (80) according to claim 6 or 7, wherein, Determining the inclination includes: obtaining data from a positioning system, the data including information about the inclination of the ground at the location of the mining vehicle (10).

9. The method (80) according to any one of the preceding claims, further comprising: Determining which one of at least two gears (41, 42) of the mining machine is engaged; And Setting the braking torque based on the determination.

10. The method (80) according to claim 9, further comprising: Preventing a shift to a higher gear when the available charging power is lower than a second predetermined value, the second predetermined value being lower than the first predetermined value.

11. A computer program (70) including instructions, which when executed by a computer cause the computer to implement the method (80) according to any one of the preceding claims.

12. A computer-readable medium including instructions, which when executed by a computer cause the computer to implement the method (80) according to any one of claims 1 to 11. A traction control system (60) for controlling the traction speed of a mining vehicle (10) during downhill travel, wherein the mining vehicle (10) includes an electric drive system (20) and an electrical energy storage (30), the electric drive system (20) includes a traction engine (21) and at least one inverter (22), the traction control system (60) includes means (61) for communicating with the electric drive system (20), a processing circuit (62) and a memory (63), the memory containing instructions executable by the processing circuit (62), wherein the traction control system (60) is configured to: Set the braking torque of the traction engine (21); Determine the available charging power of the electrical energy storage (30); When the available charging power is below a first predetermined value, calculate a reference speed of the traction engine (21) based on the available charging power and the set braking torque; And Control the traction speed of the mining vehicle (10) by controlling the speed of the traction engine (21) to the reference speed.

13. A mining vehicle (10) comprising the traction control system (60) according to claim 13, an electric drive system (20) including a traction engine (21) and at least one inverter (22), and an electrical energy storage (30).

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