Temperature-based resistive braking capacity

Abstract

This document provides a system comprising: a resistor grid including a plurality of resistive elements, the resistor grid being electrically coupled to a motor of an electrically driven machine; a temperature sensor arranged to measure the temperature of at least one of the plurality of resistive elements; control circuitry including one or more processors and a memory configured to store instructions that, when executed by the one or more processors, cause the control circuitry to: determine the temperature of at least one resistive element based on the measurement from the temperature sensor; and determine a resistive braking capacity of the resistor grid within a power capacity difference based on the determined temperature of the resistive element; and a display configured to present a graphical representation of the resistive braking capacity of the resistor grid relative to the power capacity difference.

Description

Technical Field

[0001] This disclosure relates in general to the field of resistor grid assemblies for resistive braking systems of electrically driven machines, and more specifically to improved systems and methods for operating such resistor grid assemblies. Background Technology

[0002] Resistor grid systems for dynamic braking in machinery, such as electric locomotives and diesel-electric locomotives, off-highway machinery, and other heavy equipment, are well known. An electric drive motor generates current during braking, and the resistor grid system comprises multiple resistive elements that dissipate the generated electricity as heat. Therefore, the resistor grid system complements friction brakes and minimizes wear on the friction braking components of the machine.

[0003] The heat dissipation capacity of a resistor grid is limited by the maximum permissible temperature of each component of the resistor element. Therefore, the heat dissipation capacity of a resistor grid system may be reduced based on the system's component design, the environmental conditions surrounding the machine, and the altitude at which the machine operates. Failure to properly account for these variables may lead to failure of the resistor grid system or underutilization of its full capacity. Improved resistor grid system design and control systems are needed to extend the life of resistive braking systems and achieve maximum braking capacity under various operating conditions. Summary of the Invention

[0004] A first aspect provided herein relates to a system comprising: a resistor grid including a plurality of resistor elements electrically coupled to a motor of an electrically driven machine; a temperature sensor positioned to measure the temperature of at least one of the plurality of resistor elements; control circuitry including one or more processors and a memory configured to store instructions that, when executed by the one or more processors, cause the control circuitry to: determine the temperature of the at least one resistor element based on the measurement from the temperature sensor; and determine a resistive braking capacity of the resistor grid within a power capacity difference based on the determined temperature of the resistor element; and a display configured to present a graphical representation of the resistive braking capacity of the resistor grid relative to the power capacity difference. In some embodiments, the temperature of the resistor element is the temperature of the resistor plate of the resistor element. In some embodiments, the temperature of the resistor element is the temperature of the resistive insulator of the resistor element. In some embodiments, the temperature sensor is a sensor that directly or indirectly measures temperature. In other embodiments, the temperature sensor is one or more sensors or other data sources that provide auxiliary data sufficient to enable the one or more processors to determine the temperature of at least one of the plurality of resistive elements.

[0005] In some embodiments, the power capacity difference lies between the peak power capacity and the continuous power capacity. In some embodiments, the system further includes a second temperature sensor configured to measure the temperature of ambient air, wherein the control system is further configured to determine the resistive braking capacity of the resistor grid based on the measured temperature of the ambient air. In some embodiments, the ambient air temperature sensor is a sensor that directly or indirectly measures the temperature of the ambient air. In other embodiments, the ambient air temperature sensor is one or more sensors or other data sources that provide auxiliary data sufficient to enable the one or more processors to determine the ambient air temperature. In some embodiments incorporating an ambient air temperature sensor, the control system is further configured to determine the continuous resistive capacity of the resistor grid based on at least one of the measured temperature and / or the density of the ambient air, and the display is further configured to present a graphical representation of the continuous resistive capacity of the resistor grid relative to the capacity difference.

[0006] In some embodiments, the control system is configured to determine the temperature change of at least one of the plurality of resistive elements; and to update the graphical representation of the resistive braking capacity based on the temperature change of the at least one resistive element. In some embodiments, the graphical representation includes a first indication of peak power capacity, a second indication of continuous power capacity, and a third indication of the resistive braking capacity relative to the first and second indications. In some embodiments, the graphical representation includes a bar graph that includes the peak power capacity at a first end and the continuous power capacity at a second end, including a first portion of the first end colored with a first color and a second portion of the second end colored with a second color, and wherein the third indication includes a line indicating the positioning of the resistive braking capacity relative to the first and second ends.

[0007] The second aspect provided herein relates to a method for controlling an electrically driven machine, the method comprising: determining, by one or more processors, the temperature of a resistive element of a resistive grid electrically coupled to a motor of the electrically driven machine; determining, by the one or more processors, a resistive braking capacity of the resistive grid within a power capacity difference based on the determined temperature of the resistive element; and displaying, by the one or more processors, a graphical representation of the resistive braking capacity of the resistive grid relative to the power capacity difference on a display of the electrically driven machine. In some embodiments, the temperature of the resistive element is the temperature of the resistive tab of the resistive element. In some embodiments, the temperature of the resistive element is the temperature of the resistive insulator of the resistive element. In some embodiments, the temperature of the resistive element of the resistive grid is determined based on data provided by a temperature sensor. In other embodiments, the temperature of the resistive element of the resistive grid is determined based on data provided by one or more auxiliary sensors or other data sources, which provide auxiliary data (such as air temperature, pressure, flow rate, etc.).

[0008] In some embodiments, the power capacity difference lies between the peak power capacity and the continuous power capacity. In some embodiments, the method further includes: determining an ambient air temperature by the one or more processors; and determining the peak power capacity of the power capacity difference by the one or more processors based on the ambient air temperature. In some embodiments, the method includes: determining an ambient air density by the one or more processors, wherein the determination of the peak power capacity is based on the ambient air temperature and the ambient air density.

[0009] In some embodiments, the method includes: determining, by the one or more processors, the continuous resistive capacity of the power capacity difference based on at least one of the ambient air temperature and the ambient air density; and displaying the continuous resistive capacity to an operator of the electrically driven machine. In some embodiments, the method includes: determining, by the one or more processors, the temperature change of the resistor element; and updating, by the one or more processors, the graphical representation of the resistive braking capacity based on the temperature change.

[0010] In some embodiments, the graphical representation includes a first indication of peak power capacity, a second indication of continuous power capacity, and a third indication of the resistive braking capacity relative to the first and second indications. In some embodiments, the graphical representation includes a bar graph that includes the peak power capacity at a first end and the continuous power capacity at a second end, including a first portion of the first end colored with a first color and a second portion of the second end colored with a second color, and wherein the third indication includes a line indicating the positioning of the resistive braking capacity relative to the first and second ends.

[0011] The third aspect provided herein relates to an electrically driven machine comprising: a resistor grid including a plurality of resistor elements electrically coupled to a motor of the electrically driven machine; a temperature sensor arranged to measure the temperature of at least one of the plurality of resistor elements; control circuitry including one or more processors and a memory configured to store instructions that, when executed by the one or more processors, cause the control circuitry to: determine the temperature of the at least one resistor element based on the measurement from the temperature sensor; and determine a resistive braking capacity of the resistor grid within a power capacity difference based on the determined temperature of the resistor element; and a display configured to present a graphical representation of the resistive braking capacity of the resistor grid relative to the power capacity difference. In some embodiments, the temperature of the resistor element is the temperature of the resistor plate of the resistor element. In some embodiments, the temperature of the resistor element is the temperature of the resistive insulator of the resistor element.

[0012] In some embodiments, the temperature sensor is a sensor that directly or indirectly measures temperature. In other embodiments, the temperature sensor is one or more sensors that provide auxiliary data sufficient to enable the one or more processors to determine the temperature of at least one of the plurality of resistive elements. In still other embodiments, the temperature sensor is one or more other data sources that provide auxiliary data sufficient to enable the one or more processors to determine the temperature of at least one of the plurality of resistive elements.

[0013] In some embodiments, the power capacity difference lies between the peak power capacity and the continuous power capacity. In some embodiments, the electric drive further includes a second temperature sensor configured to measure the temperature of ambient air, and the control system is further configured to determine the resistive braking capacity of the resistor grid based on the measured temperature of the ambient air. In some embodiments, the control system is further configured to determine the continuous resistive capacity of the resistor grid based on at least one of the measured temperature of the ambient air and / or the density of the ambient air, and the display is further configured to present a graphical representation of the continuous resistive capacity of the resistor grid relative to the capacity difference.

[0014] In some embodiments, the control system is further configured to determine the continuous resistive capacity of the resistor grid based on at least one of the measured temperature of the ambient air and / or the density of the ambient air, and wherein the display is further configured to present a graphical representation of the continuous resistive capacity of the resistor grid relative to the capacity difference.

[0015] In some embodiments, the graphical representation includes: a first indication of peak power capacity, a second indication of continuous power capacity, and a third indication of the resistive braking capacity relative to the first and second indications.

[0016] In some embodiments, the graphical representation includes: a bar graph that includes the peak power capacity at a first end and the continuous power capacity at a second end, including a first portion of the first end colored with a first color and a second portion of the second end colored with a second color, and wherein the third indication includes a line indicating the positioning of the resistive braking capacity relative to the first end and the second end.

[0017] This invention is merely illustrative and is not intended to be limiting in any way. Other aspects, inventive features, and advantages of the apparatus or process described herein will become apparent from the detailed description set forth herein in conjunction with the accompanying drawings, wherein like reference numerals refer to like elements. Attached Figure Description

[0018] Figure 1 This is a side view of a machine according to an embodiment of the present disclosure.

[0019] Figure 2 According to the embodiments, it is used for Figure 1 A schematic diagram of the electric drive unit of the machine.

[0020] Figure 3 This is a perspective view of a modular resistor grid system according to an embodiment.

[0021] Figure 4 yes Figure 3 Exploded view of the modular resistor grid system.

[0022] Figure 5 This is a perspective view of a modular resistor grid assembly according to an embodiment.

[0023] Figure 6 According to the embodiments Figure 5 A perspective view of the modular resistor grid assembly.

[0024] Figure 7 This is a perspective view of a resistor element according to an embodiment.

[0025] Figure 8 This is a schematic diagram of a resistor grid system according to an embodiment.

[0026] Figure 9 This is a schematic diagram of a method for operating a resistor grid system according to an embodiment. Detailed Implementation

[0027] Before turning to the accompanying drawings, which illustrate certain embodiments in detail, it should be understood that this disclosure is not limited to the details or methods set forth in the specification or shown in the drawings. It should also be understood that the terminology used herein is for descriptive purposes only and should not be considered limiting.

[0028] Electric drive machine

[0029] Figure 1 A machine 100 that can implement the disclosed embodiments is schematically illustrated. Machine 100 can be generally described as any machine having an electric drive unit that can be connected to one or more drive wheels. Machine 100 may include vehicles such as diesel engine locomotives, underground trams, off-highway trucks, or vehicles used for mining, construction, quarrying, and other applications. However, it will be apparent that any other vehicle having an electric drive unit or a purely electric arrangement may be included in machine 100.

[0030] For the purposes of this disclosure, Figure 1In this embodiment, machine 100 is illustrated as an off-highway truck. Machine 100 may include a chassis 102 to support various components of machine 100. Machine 100 may include a dumping body 104 supported on chassis 102. Chassis 102 may also support operator cab 106, which is defined as an enclosed space. An operator in operator cab 106 can control various functions of machine 100 by issuing various operator commands using control devices such as joysticks, levers, or touch-based user interfaces.

[0031] The machine 100 may also include a set of drive wheels 108 for propulsion. In an embodiment, a set of idler wheels 110 may also be provided to steer the machine 100 in different directions. Furthermore, the machine 100 may include an articulated chassis for steering. The set of drive wheels 108 and the set of idler wheels 110 together may serve as ground engagement members of the machine 100. Figure 1 As illustrated, machine 100 also includes a modular resistor grid system 111, which is positioned next to the operator's cab 106 within machine 100. However, it will be apparent that the modular resistor grid system 111 can be positioned anywhere, depending on the design and available space within machine 100.

[0032] The machine 100 disclosed herein may be an electric machine having an electric drive unit 112. The electric drive unit 112 provides electricity to drive various components in the machine 100. In embodiments, the electricity may be generated on the machine by a generator, alternator, or other power generation device, which may be driven by an engine or any other power source. Alternatively, the electricity may not be generated on the machine, but may be supplied externally via overhead wires through a pantograph receiver, battery, or a series of capacitors to drive the machine 100.

[0033] In the illustrated embodiment, the electric drive unit 112 includes a power source 114, which may be an engine, such as an internal combustion engine, like a diesel engine, gasoline engine, or natural gas engine. The power source 114 can provide output torque at an output shaft 116 in the machine 100. The output shaft 116 can be connected to a generator 118, which may be a multiphase alternating current (AC) synchronous alternating current generator. During operation, the output shaft 116 rotates the rotor of the generator 118 to generate electricity, for example, alternating current (AC). This generated electricity can be used to operate multiple drive motors 120, which are directly coupled to or coupled via intermediate components to the set of drive wheels 108. For the purposes of this disclosure, the drive motors 120 may be variable speed, reversible AC motors.

[0034] Electric drive unit and dynamic braking system

[0035] Figure 2 A schematic diagram of the electric drive device 112 is shown. The electric drive device 112 of this disclosure can be a direct series drive device. Figure 2 The arrangement of various components of the electric drive unit 112 in the machine 100 according to an embodiment is illustrated. In this schematic diagram, the direction of power flow in the system is indicated by arrows. Solid arrows indicate the flow of power when the machine 100 is being propelled. Conversely, in Figure 2 In the diagram, the flow of electricity in the machine 100 during braking mode is represented by dashed arrows, while dotted arrows represent the control circuit connections between the components of the electric drive unit 112.

[0036] Those skilled in the art will understand that generator 118 can generate electricity in the form of alternating current (AC). This electricity can be supplied to rectifier 122 and converted to direct current (DC). The rectified DC power can be converted back to AC power by inverter circuit 124. Inverter circuit 124 can selectively adjust the frequency and / or pulse width of the output, so that drive motor 120 connected to the output of inverter circuit 124 can operate at a variable speed. In embodiments, multiple inverter circuits 124 may be configured to be connected to drive motor 120 in machine 100.

[0037] Figure 2 A dynamic braking system 200 for machine 100 is also illustrated. The dynamic braking system 200 can be connected to the drive motor 120 of machine 100. Specifically, the dynamic braking system 200 can be operably configured to be connected to the inverter circuit 124 in machine 100. The dynamic braking system 200 can be configured to slow the propulsion of machine 100 during braking mode according to operator commands in machine 100.

[0038] According to this disclosure, the dynamic braking system 200 may include a control unit 202, which may be, but is not limited to, hardware components, computing devices or other processing equipment, and a combination of memory (such as random access memory (RAM), read-only memory (ROM), flash memory, and data structures). The control unit 202 may be configured to execute instructions (e.g., the processing equipment may be configured to execute instructions stored on a data structure of the control unit 202). The control unit 202 may be configured to receive operator commands from the machine 100. Furthermore, the control unit 202 may determine, at least in part, whether to place the machine 100 into braking mode based on the operator commands. To initiate braking of the machine 100, the control unit 202 may generate a braking signal (illustrated by dotted lines) for the inverter circuit 124. Dashed arrows indicate optional signals, inputs, or data 211 that the control unit 202 may receive from the resistor grid system 111 during operation.

[0039] The braking signal can be received by the inverter circuit 124 in machine 100. The braking signal can carry a command to reverse the torque polarity of the drive motor 120. This causes the drive motor 120 to act as a generator, thereby using mechanical power in the form of rotational energy from the set of drive wheels 108 to generate electricity. This electricity can be supplied back to the electric drive unit 112 in machine 100.

[0040] The dynamic braking system 200 can also be configured to provide regenerative braking in the machine 100. For this purpose, the dynamic braking system 200 may include an energy storage unit 204. The energy storage unit 204 may include a battery or a plurality of capacitors, which are configured to be connected to a drive motor 120 in the electric drive unit 112. As during braking mode, the drive motor 120 may generate electricity, which the energy storage unit 204 may store for later use by the machine 100.

[0041] This disclosure applies to many machines, such as large off-highway trucks (e.g., dump trucks), which are commonly used in mines, construction sites, and quarries. Machine 100 may have a high payload capacity and a travel speed of several miles per hour when fully loaded. Machine 100 may also need to operate in a variety of environments, at a variety of altitudes, and successfully traverse steep slopes in dry or wet conditions.

[0042] Typically, friction brakes coupled to the set of drive wheels and idler wheels are used to stop or slow down such machines. These friction brakes are effective, but can wear out with prolonged use. To overcome this problem, the dynamic braking system 200 of the machine 100 of this disclosure can operate in combination with or without these friction brakes. The dynamic braking system 200 can supplement these friction brakes in the machine 100, thereby helping to reduce wear on such brakes.

[0043] The dynamic braking system 200 can activate upon operator command to place the machine 100 into braking mode. Specifically, the operator command can be received by the control unit 202 within the dynamic braking system 200. The control unit 202 generates a braking signal, which is at least partially determined by the operator command. This determination or calculation can be based on various operating parameters of the machine 100, such as current speed, current payload, acceleration, desired speed, etc.

[0044] Subsequently, the braking signal can be received by the inverter circuit 124 in the electric drive unit 112 of the machine 100. In braking mode, the electric drive unit 112 can reverse the torque polarity of the drive motor 120, thereby causing the drive motor 120 to act as a generator. In this mode, the drive motor 120 can use the power of the set of drive wheels 108, thereby ultimately releasing the mechanical energy of the set of drive wheels 108 and achieving deceleration or braking of the machine 100. In addition, the drive motor 120 consumes the mechanical power of the set of drive wheels 108 to generate electricity in the electric drive unit 112.

[0045] The generated electricity can be fed to the dynamic braking system 200 in the electric drive unit 112. The generated electricity (which may be in AC form) can be fed via an inverter 124 that converts AC power to DC power. In an embodiment where the machine 100 has regenerative braking, a portion of the generated electricity can be supplied to the modular resistor grid system 111 for dissipation as heat, while the remainder can be supplied to the energy storage unit 204 for later use by the machine 100.

[0046] Modular resistor grid system

[0047] The dynamic braking system 200 may include a modular resistor grid system 111. The modular resistor grid system 111 may dissipate some or all of the generated power as heat. Figure 3 A perspective view of a modular resistor grid system 111 according to aspects of this disclosure is illustrated. Figure 4 Examples Figure 3 Exploded view of the modular resistor grid system.

[0048] refer to Figure 3 and Figure 4The modular resistor grid system 111 includes a mounting base 302, a fan 310, and a modular resistor grid assembly 400. The mounting base 302 may be permanently or removably coupled to machine 100. The mounting base 302 provides a support structure to which other components of the modular resistor grid system 111 can be secured, connected to, and / or coupled to the dynamic braking system 200 of machine 100. The mounting base 302 may include a frame 304 and one or more brackets 306. The frame 304 may include rigid support members (such as rods, rails, columns, tracks, or other suitable elements) to secure components of the modular resistor grid system 111 to machine 100. The brackets 306 may be selectively movable, such that one or more brackets 306 can be fastened along the frame 304 to a first position, released to allow sliding along the length of the frame 304 to a second position, and then tightened to secure the bracket 306 in the second position. The bracket 306 may also include a mounting feature 308 configured to align with or abut against components of the modular resistor grid system 111, such that these components can be fastened together by bolts, welds, or other suitable fasteners. For example, according to aspects of this disclosure, in Figure 3 and Figure 4 In this configuration, movable brackets 306 are coupled to mounting features 308, the shapes of which are designed to match the cylindrical profile of the modular resistor grid system 111. In this way, multiple modular resistor grid assemblies 400 with different axial lengths L can be coupled to the mounting base 302 by sliding along the frame 304 and fixing the movable brackets 306 as needed.

[0049] The modular resistor grid system 111 also includes a fan 310. The fan 310 is configured, for example, during resistive braking mode of the machine 100, to blow cooling air through the modular resistor grid assembly 400 to dissipate heat. The fan 310 may include a blade assembly 312 configured to direct air toward or through the modular resistor grid assembly 400 as the blade assembly 312 rotates. A power source 314 (e.g., an electric motor, battery, etc.) may power the fan 310, and a hub assembly 316 may direct air toward the modular resistor grid assembly 400 and / or enclose and protect components of the fan 310.

[0050] The modular resistor grid system 111 includes a modular resistor grid assembly 400. The modular resistor grid assembly 400 facilitates resistive braking by receiving power from the machine 100 and dissipating that power as heat. In some embodiments, the modular resistor grid assembly 400 may be formed as a single unit, or may be formed from a single modular resistor grid. In other embodiments, the modular resistor grid assembly 400 may be formed by coupling a plurality of modular resistor grids 402 together (e.g., see discussion below). Figure 5 and Figure 6 The modular resistor grid assembly 400 includes a housing 404 that provides support for the various components of the modular resistor grid system 111. Figures 3 to 5 In the illustrated example, the housing 404 is cylindrical, having an inner wall 406 and an outer wall 408. The housing 404 can be of any shape and can be divided into one or more modular sections. For example, the housing 404 of a modular resistor grid assembly 400 can be formed by coupling two or more modular resistor grids 402 together, each modular resistor grid having a housing 404 that encloses one or more resistor elements 410. The modular resistor grids 402 can be cylindrical, semi-cylindrical, quadrant-shaped, wedge-shaped, triangular, or other suitable shapes. The number of sub-sections of the housing 404 and the number of individual modular resistor grids 402 that can be coupled together to form the modular resistor grid assembly 400 can vary depending on space constraints in the machine 100.

[0051] For example, Figure 5 and Figure 6 An embodiment of a modular resistor grid assembly 400 is illustrated, which is divided into four quadrant-shaped modular resistor grids 402, which are assembled together in machine 100. Both the modular resistor grid assembly 400 and the modular resistor grids 402 include at least one resistor element 410 disposed between the inner wall 406 and the outer wall 408 of the housing 404. The modular resistor grid assembly and / or the modular resistor grids 402 may include two or more resistor elements 410 (e.g., multiple resistor elements 410) stacked closely in a stacked configuration abutting each other in an end-to-end orientation. The resistor elements 410 may be uniformly arranged in the housing 404 to maintain air space between them. This uniform spacing ensures adequate cooling airflow between the resistor elements 410 in the modular resistor grid system 111. Furthermore, one or more cooling air vents may be provided in the housing 404 for circulating cooling air within the modular resistor grid system 111.

[0052] Figure 7A resistor element 410 according to an embodiment is illustrated. The resistor element 410 includes a first insulator 412, a second insulator 414, and one or more resistor plates 416 mounted to the first insulator 412 and the second insulator 414. In the illustrated example, the resistor plates 416 are mounted between the first insulator 412 and the second insulator 414, which are then anchored to the inner wall 406 and outer wall 408 of the housing 404 of the modular resistor grid assembly 400 and / or the modular resistor grid 402. Furthermore, one or more resistor elements 410 may be arranged in one or more rows, substantially parallel to each other, in a close face-to-face relationship, thereby forming an axial airflow path therebetween. Multiple resistor pieces 416 of resistor element 410 may be connected in series within each modular resistor grid 402 and / or modular resistor grid assembly 400 to provide a continuous current path between the input terminal 419 and the output terminal 420 of the modular resistor grid 402 and / or modular resistor grid assembly 400 (see [link to documentation]). Figure 5 and Figure 6 For this purpose, conductive members may be provided in the housing 404 to electrically connect two or more resistor pieces 416 in the modular resistor grid system 111. The conductive member may be a conductive wire, a welded component, etc. The resistor units 410 may be connected in such a manner that the modular resistor grid system 111 can have two current circuits (i.e., a contactor power supply circuit and a chopper power supply circuit).

[0053] As illustrated, the first insulator 412 and the second insulator 414 may be in the form of a block made of an insulating material, such as silicon-bonded laminated mica, ceramic, glass-reinforced material, etc. However, any other material with insulating properties may be used to form the first insulator 412 and the second insulator 414. The first insulator 412 may be secured to the outer wall 408 of the housing 404 by some fastening member, such as nuts and bolts, screws, etc. The second insulator 414 may be secured to the inner wall 406 of the housing 404 in a similar manner. The first insulator 412 and the second insulator 414 may each include one or more holes 418 formed therein. Furthermore, the holes 418 may not extend through the first insulator 412 or the second insulator 414 and may be configured to receive and mount a resistor piece 416 between the first insulator 412 and the second insulator 414.

[0054] Resistor sheet 416 may be formed from a continuous strip of resistive material (such as stainless steel). Resistor sheet 416 may include a body portion 420 extending along the longitudinal direction XX' of resistor sheet 416. In embodiments, resistor sheet 416 may also include a series of folded-back portions 422 disposed on opposite longitudinal sides of the body portion 420 of resistor sheet 416. In some configurations, resistor sheet 416 may extend along the longitudinal direction XX' in the range of about 150 mm to about 200 mm. In a specific example, resistor element 404 may have a length of about 160 mm. Resistor sheet 416 may have a pointed portion 424 disposed at an end 426 remote from the body portion 420. Alternatively, resistor sheet 416 may include two or more pointed portions 424 disposed remote from both ends 426. The pointed portions 424 of resistor sheet 416 may be adapted to be received in holes 418 of a first insulator 412 and a second insulator 414. The hole 418 provides some clearance for the movement of the tip portion 424 within it. This allows the resistor piece 416 to move in the longitudinal direction XX' within the resistor element 410 during thermal expansion and contraction.

[0055] During resistive braking mode, the generated power can enter the modular resistor grid system 111 via input terminal 419 and flow through the resistor plates 416 in the resistor elements 410 of the modular resistor grid system 111 as heat dissipation. Specifically, heat is generated by the body portion 420 of the resistor plate 416. This generated heat can be dissipated to the first insulator 412 and the second insulator 414, raising the temperature of the first insulator 412 and the second insulator 414 in the resistor element 410. According to industry standards, the normal continuous operating temperature of the first insulator 412 and the second insulator 414 is in the range of 300 to 400 degrees Celsius. In short time intervals, the temperature of the first insulator 412 and the second insulator 414 may reach higher values ​​due to surges, but if the temperature rises to the critical temperature or above the maximum operating temperature over a long period of time, the lifespan of the first insulator 412 and the second insulator 414 may be significantly shortened. In addition, the mechanical stability of resistor 416 may be affected, causing resistor 416 to bend and ultimately leading to the rapid failure of dynamic braking system 200.

[0056] Temperature-based resistive braking capacity

[0057] Continue to refer to Figures 2 to 7During operation, the modular resistor grid system 111 has a capacity for dissipating energy, which can be expressed as a power capacity. For example, the power capacity of the modular resistor grid system 111 may be 1 MW. The power capacity of the modular resistor grid system 111 may vary depending on the geometry and properties of the resistor grid system and the operating conditions of the system. The power capacity for dissipating energy of the resistor grid system 111 may depend on (but is not limited to) the operating conditions of the fan 310, the temperature of the ambient air, the density of the ambient air, and the temperature of the resistor element 410, etc.

[0058] The power capacity reported or measured by the modular resistor grid system 111 can be either continuous power capacity or transient power capacity. This is when the grid element 410 is at its maximum sustainable temperature T. max At this time, the continuous power capacity of the resistor grid system 111 can be determined. The power capacity of the resistor grid system 111 may be affected by the highest temperature T that the resistor element 410 can safely withstand. max The maximum temperature is limited by the material and geometry of the resistor element. When operating in continuous power capacity mode, the resistor grid system 111, together with the resistor element 410, is at or near T. max The system operates at a roughly steady-state temperature. In this mode, the resistor grid system 111 dissipates energy as heat at a rate approximately the same as the rate at which energy is supplied to the system as charge. Depending on the specific implementation, the continuous power capacity of the resistor grid system 111 may depend on several variables, including but not limited to the length of the electrical path provided by the resistor elements, the resistor grid material, the fan duty cycle, and convection considerations (such as the geometry of the angle and surface of the grid elements relative to the cross airflow provided by the fan operation).

[0059] When the resistor grid system 111 is below the maximum operating temperature T of the grid element 410... max When operating under certain conditions, transient power capacity may occur. In this mode, the resistor grid system will transiently have increased power capacity, which can be used to absorb and dissipate capacity exceeding that available during continuous power mode operation. During transient mode operation, the resistor grid system 111 is able to dissipate an amount of energy approximately equal to the continuous power capacity, but can also absorb additional energy via the heating of the resistor element 410. The thermal capacity of this system can provide additional power capacity for resistive braking purposes.

[0060] The peak power capacity of a resistor grid system can occur when the resistor elements are at their lowest temperatures. In air-cooled systems, the lowest resistor element temperature is equal to the ambient air temperature. A power capacity difference may exist in the system, defined by the peak power capacity and the sustained power capacity. By considering the additional power capacity available to the resistor grid when the resistor elements are below their maximum operating temperature, an additional resistive braking capacity can be provided to the vehicle. This additional resistive capacity can be utilized by the operator to reduce the amount of friction braking required for deceleration or otherwise controlling the vehicle. The systems and methods provided herein enable the operator to utilize this additional resistive braking capacity.

[0061] refer to Figure 8 According to an exemplary embodiment of this disclosure, a schematic diagram of a control circuit 500 for a resistive braking system is provided. When operating at temperatures below the maximum operating temperature of the resistive elements' components (e.g., resistor plates and / or resistor insulators), the control circuit 500 may account for additional braking capacity available to the resistive grid. The control circuit 500 may be configured to provide control over the resistive braking system and the resistive grid system of a vehicle, including a power source, drive motor, inverter, and resistive grid system (as previously described), while receiving data regarding the operating temperature of components or portions of the resistive grid system.

[0062] like Figure 8 As shown, the control circuit 500 may include a control unit 510, an inverter circuit 512, and a temperature sensor 520. The control circuit 500 includes one or more processors 504 and a computer memory 502. In some embodiments, the control circuit 500 includes an auxiliary data source 518 and / or a display 516 for displaying the resistive braking capacity of the resistor grid system to the operator of the vehicle. In some embodiments, the temperature sensor 520 is a sensor that directly or indirectly measures temperature. In other embodiments, the temperature sensor 520 is one or more sensors or other data sources that provide auxiliary data sufficient to enable one or more processors to determine the temperature of at least one of a plurality of resistor elements. The control unit 510 may be a combination, but not limited to, of, an instruction set stored on the computer memory 502, one or more processors 504 configured to execute the instruction set, random access memory (RAM), read-only memory (ROM), flash memory, and data structures, etc. The control unit 510 is configured to receive and output signals. The control circuit 500 is electrically coupled to the temperature sensor 520, which is configured to measure the temperature of one or more parts of the resistor grid system 514, such as resistor grid elements.

[0063] Control unit 510 may optionally be configured to receive additional signals 570 from auxiliary data source 518. Auxiliary data sources may include, but are not limited to, remote or local databases or servers, computing modules, processors, memory, and / or local or remote sensors. For example, control unit 510 may receive signals 570 corresponding to: the temperature of the ambient air around the vehicle, the density of the ambient air around the vehicle, the altitude at which the vehicle is operating, the time of day, and information about the planned route of the vehicle, etc. Even though a single source 518 is shown, it should be understood that each of these data signals may be provided by a separate sensor or other data source, such as a temperature sensor configured to measure the temperature of the ambient air around the vehicle or an altimeter configured to measure the altitude at which the vehicle is operating. It should also be understood that a single source may provide multiple data points. For example, a remote server may send signals providing data about the vehicle's altitude and ambient air density or pressure.

[0064] The control unit 510 can also be configured to transmit a braking signal 550 to the inverter circuit 512. This braking signal can be received by the inverter circuit 512 in the vehicle. The braking signal may carry a command to reverse the torque polarity of a drive motor (not shown) coupled to the inverter circuit 512, thereby providing braking to the vehicle and generating charge in the drive motor. Excess charge can be directed to a resistor grid system for heat dissipation or to a battery for storage.

[0065] In some embodiments, temperature sensor 520 may be, but is not limited to, a thermocouple, a digital temperature sensor, an infrared detector, a thermopile sensor, a resistance temperature detector, or a negative temperature coefficient thermistor. The temperature sensor provides control unit 510 with a resistance temperature signal 540 corresponding to one or more temperatures associated with one or more resistor elements. In some embodiments, temperature sensor 520 may be one or more sensors or other data sources that provide auxiliary data enabling one or more processors to determine the temperature of a resistor grid element. Measuring multiple resistor element locations increases data redundancy and also helps identify hot spots in the resistor grid. Such hot spots can indicate conduction or convection problems in the resistor grid. The temperature sensor may also optionally or additionally provide information corresponding to the temperature of other parts of the resistor grid system. For example, the temperature of the resistor insulator or grid cover may also be of interest and therefore can be measured.

[0066] Control unit 510 is configured to use one or more processors 504 and memory 502 to determine the resistive braking capacity of resistor grid system 514 based on measured temperature data associated with resistor grid system 514 (measured by temperature sensor 520). The resistive braking capacity will fall within the power capacity difference defined by the peak power capacity and continuous power capacity of resistor grid system 514. In some embodiments, the measured temperature is the temperature of one or more resistor elements. In other embodiments, the measured temperature is the temperature of the resistor plates of the resistor elements. In some embodiments, the measured temperature is the temperature of other components of resistor grid system 514, such as resistor insulators, inner walls, or outer walls.

[0067] Continue to refer to Figures 5 to 8 The control unit 510 may optionally be configured to determine the resistive braking capacity of the resistor grid system 514 based on other available data, such as ambient air temperature, ambient air density, ambient air pressure, contamination of resistor elements, altitude at which the vehicle is operating, or the planned route of the vehicle. This list of potential considerations is not intended to be exclusive—other variables may be considered when determining the resistive braking capacity of the resistor grid system 514.

[0068] Control circuitry 500 may optionally be configured to provide an output signal 560 to interface 516. Thus, information determined, calculated, derived, identified, or otherwise present in control unit 510 may be transmitted to other device 516 via output signal 560. In some embodiments, interface 516 is a user interface, such as a graphical display. As a non-limiting example, the display may be positioned in the cab to show the operator of the vehicle the capacity of the resistive grid, thereby informing the operator of the availability of additional resistive braking capacity beyond the resistive braking capacity. In a non-limiting use case scenario, the operator may want to know how much capacity is available in the resistive grid braking system before initiating downhill transport to avoid increased wear on the vehicle's friction braking components. Control unit 510 may display the available resistive capacity and an indication of the continuous resistive capacity to the operator.

[0069] The graphical display includes an indication of the resistive braking capacity of the resistor grid system. It may also include an indication of the peak power capacity determined by the control unit 510 using one or more processors 504 and memory 502. In some embodiments, the determination of the peak power capacity takes into account one or both of ambient air temperature and pressure. The presented display may also indicate the continuous power capacity and power capacity difference of the resistor grid system; in some embodiments, the continuous power capacity and power capacity difference may also be determined by taking into account one or both of ambient air temperature and pressure. In other embodiments, the continuous power capacity is a set value in computer memory 502 or received by the control unit 510 from another source 518. In some embodiments, the display includes colored portions to indicate the various information presented. In some of these embodiments, the colored bars indicate relative values ​​of peak power capacity, continuous power capacity, resistive braking capacity, and power capacity difference.

[0070] These principles can be applied to methods of operating vehicles using resistive braking capacity. (Reference) Figure 9 The diagram illustrates a method 600 for operating such a vehicle according to an embodiment. In a first step 610, one or more processors on the vehicle determine the temperature of at least one resistive element in the resistive grid system that provides resistive braking capacity to the vehicle. As described above, in some embodiments, the temperature is measured by a sensor located near or inside the resistive grid system, and may include a thermocouple, digital temperature sensor, infrared detector, thermopile sensor, resistance temperature detector, or negative temperature coefficient thermistor. In other embodiments, the temperature sensor may be one or more sensors or other data sources that provide auxiliary data that enables one or more processors to determine the temperature of the resistive grid element.

[0071] Once the temperature of at least one resistor element is determined, in the second step 620, one or more processors may determine the capacity of the resistor grid system based on the determined temperature of the resistor element relative to the power capacity difference. As previously described, when the temperature of the resistor element is below the maximum operating temperature, the resistor grid system may have an additional capacity above its continuous capacity. The power capacity difference may extend, for example, from the peak or maximum power capacity (available when the temperature of the resistor grid element is approximately at ambient air temperature) to the continuous power capacity (available when the temperature of the resistor grid element is approximately at the maximum operating temperature).

[0072] Figure 9The additional steps, shown in dashed lines, include step 640, which determines the temperature of the ambient air in which the vehicle operates. Furthermore, it includes step 650, which determines the peak power capacity of the resistor grid system based on the determined ambient air temperature. The peak power capacity of the resistor grid system can also be presented by one or more processors on a display available to the vehicle operator, thereby providing the operator with additional information about the potential capacity of the braking system. Additionally, the method may also take into account the density of the ambient air. In such cases, this information takes into account the density of the ambient air before the peak power capacity of the resistor grid system is presented on the operator's display.

[0073] In the third step 630, the available resistive braking capacity of the vehicle is presented by one or more processors relative to the power capacity difference. This step can be performed using a display (preferably a display readily available to the vehicle's operator). For example, for a vehicle using a local operator, this step can utilize a display located in the vehicle's cab. For a remote operator, one or more processors can present the resistive braking capacity on a remote display. Power capacity difference, peak power capacity, and continuous power capacity may also be displayed, if desired.

[0074] It should be understood that the methods disclosed in this article are not limited to... Figure 9 The exact steps shown do not necessarily have to be performed in the order described. A step may be iterated multiple times before or after performing another step. In some embodiments, the determination of ambient air temperature and the determination of peak power capacity are not performed. In other embodiments, the determination of ambient air temperature and the determination of peak power capacity are not performed. In still other embodiments, the determination of ambient air temperature and the determination of peak power capacity are not performed.

[0075] The various operations described in this article can be implemented on a computer system. Figure 8 A block diagram of a representative computing system that can be used to implement the present disclosure is shown, the representative computing system including one or more processors 504 and computer memory 502. The computing system may be implemented, for example, as a consumer device such as a smartphone, other mobile phone, tablet computer, wearable computing device (e.g., smartwatch, glasses, head-mounted display), desktop computer, laptop computer, etc., or implemented using distributed computing devices. In some embodiments, control unit 510 is the computing system. In other embodiments, the computing system is a part or subsystem of control unit 510. In some embodiments, the computing system may include conventional computer components such as one or more processors 504, storage devices or computer memory 502, network interfaces, user input devices, and user output devices 516.

[0076] A network interface coupled to or otherwise communicating with a computer system provides connectivity to a wide area network (e.g., the Internet), and the WAN interface of a remote server system may also be connected to that wide area network. The network interface may include a wired interface (e.g., Ethernet) and / or a wireless interface that implements various RF data communication standards, such as Wi-Fi, Bluetooth, UWB, or cellular data network standards (e.g., 3G, 4G, 5G, 60GHz, LTE, etc.).

[0077] User input devices may include any device (or devices) through which a user can provide signals to a computer system; the computer system may interpret these signals as indications of specific user requests or information. User input devices may include any or all of the following: keyboard, touchpad, touchscreen, mouse or other pointing device, scroll wheel, click wheel, knob, button, switch, keypad, microphone, and sensors (e.g., motion sensors, eye-tracking sensors, etc.).

[0078] User output device 516 may include any means by which a computer system can provide information to a user. For example, user output device 516 may include a display for displaying images generated by or delivered to the computing system 516. The display may employ various image generation technologies, such as liquid crystal displays (LCDs), light-emitting diodes (LEDs) (including organic light-emitting diodes (OLEDs)), projection systems, or cathode ray tubes (CRTs), and associated electronics (e.g., digital-to-analog converters or analog-to-digital converters, or signal processors). Devices such as touchscreens may be used as both input and output devices. Output device 516 may complement or replace the display. Examples include indicator lights, speakers, haptic "display" devices, and printers.

[0079] Some specific implementations include electronic components (such as microprocessors, storage devices, and memories) that store computer program instructions in a computer-readable storage medium (e.g., a non-transitory computer-readable medium). Many of the features described in this specification can be implemented as processes specified as sets of program instructions encoded on a computer-readable storage medium. When these program instructions are executed by one or more processors, they cause the processor to perform various operations indicated in the program instructions. Examples of program instructions or computer code include: machine code, such as machine code generated by a compiler; and files containing high-level code that are executed by a computer, electronic component, or microprocessor using an interpreter. With appropriate programming, a processor can provide a variety of functionalities to a computing system, including any of the functionalities described herein that are performed by a server or client, or other functionalities associated with message management services.

[0080] It should be understood that the description of the computer systems provided herein is illustrative, and changes and modifications to the configuration or implementation of the computer systems are possible. Computer systems used in conjunction with this disclosure may have other capabilities not specifically described herein. Furthermore, while the computing systems are described with reference to specific blocks, it should be understood that these blocks are defined for ease of description and are not intended to imply a specific physical arrangement of the component parts. For example, different blocks may reside in the same facility, in the same server rack, on the same motherboard, or on the same circuitry. Moreover, these blocks do not necessarily correspond to physically different components. For example, blocks can be configured to perform various operations by programming the processor or providing appropriate control circuitry, and whether various blocks can be reconfigured depends on how the initial configuration is obtained. Specific embodiments of this disclosure can be implemented in various devices, including electronic devices implemented using any combination of circuitry and software.

[0081] Unless otherwise specified, as used herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean + / - 10% of the disclosed value. As used herein with respect to structural features (e.g., describing shape, size, orientation, direction, relative positioning, etc.), the terms “approximately,” “about,” “substantially,” and similar terms are intended to cover minor structural variations that may occur, for example, during manufacturing or assembly, and are intended to have a broad meaning consistent with common usage accepted by one of ordinary skill in the art to which the subject matter of this disclosure pertains. Therefore, these terms should be interpreted as indicating that non-substantial or insignificant modifications or alterations to the described and claimed subject matter are considered to fall within the scope of this disclosure as set forth in the appended claims.

[0082] As used herein, the term “coupled” and its variations mean that two components are directly or indirectly connected to each other. Such a connection can be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). Such a connection can be achieved by: two components being directly coupled to each other; two components being coupled to each other using a single intermediate component and any additional intermediate component; or two components being coupled to each other using an intermediate component that is integral with one of the two components to form a single whole. If “coupled” or its variations are modified by an additional term (e.g., direct coupling), the general definition of “coupled” provided above is modified by the colloquial meaning of the additional term (e.g., “direct coupling” means the connection of two components without any single intermediate component), resulting in a narrower definition than the general definition of “coupled” provided above. Such coupling can be mechanical, electrical, or fluid.

[0083] The positioning of elements mentioned herein (e.g., "top", "bottom", "above", "below") is used merely to describe the orientation of the various elements in the accompanying drawings. It should be noted that, according to other embodiments, the orientation of the various elements may differ, and such variations are intended to be covered by this disclosure.

[0084] Hardware and data processing components for implementing the various processes, operations, exemplary logic, logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed using general-purpose single-chip or multi-chip processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof, which are intended to perform the functions described herein. A general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, a combination of one or more microprocessors with a DSP core, or any other such configuration. In some embodiments, specific processes and methods may be executed by circuitry dedicated to a given function. Memory (e.g., memory, memory cell, storage device) may include one or more means (e.g., RAM, ROM, flash memory, hard disk storage devices) for storing data and / or computer code to perform or facilitate the various processes, layers, and modules described in this disclosure. The memory may be or include volatile or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. According to an exemplary embodiment, the memory is communicatively connected to a processor via processing circuitry and includes computer code for (e.g., by the processing circuitry or processor) performing one or more of the processes described herein.

[0085] This disclosure contemplates methods, systems, and program products for implementing various operations on any machine-readable medium. Embodiments of this disclosure may be implemented using existing computer processors; or by a dedicated computer processor for a suitable system, incorporated for this or another purpose; or by a hardwired system. Embodiments within the scope of this disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available medium accessible by a general-purpose or special-purpose computer or other machine with a processor. As an example, such machine-readable media may include RAM, ROM, EPROM, EEPROM, or other optical disk storage devices, magnetic disk storage devices, or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures accessible by a general-purpose or special-purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, special-purpose computer, or special-purpose processing machine to perform a function or a set of functions.

[0086] Although the accompanying drawings and description may illustrate a particular order of method steps, the order of such steps may differ from the order depicted and described unless otherwise specified above. Furthermore, unless otherwise specified above, two or more steps may be performed simultaneously or partially simultaneously. Such variations may depend, for example, on the chosen software and hardware system and the designer's choices. All such variations are within the scope of this disclosure. Similarly, software implementations of the described method may be accomplished using rule-based logic and other logic through standard programming techniques to perform various connection steps, processing steps, comparison steps, and decision steps.

[0087] It is important to note that the constructions and arrangements of the various embodiments are merely illustrative. Additionally, any element disclosed in one embodiment may be incorporated into or used in any other embodiment disclosed herein.

Claims

1. A system comprising: A resistor grid comprising a plurality of resistor elements (410) electrically coupled to a motor (120) of an electrically driven machine (100). A temperature sensor (520) is arranged to measure the temperature of at least one of the plurality of resistive elements (410); A control circuit (500) includes one or more processors (504) and a memory (502) configured to store instructions that, when executed by the one or more processors (504), cause the control circuit (500) to: The temperature of at least one of the plurality of resistor elements (410) is determined based on measurements from the temperature sensor (520); as well as The resistive braking capacity of the resistor grid within the power capacity difference is determined based on the determined temperature of the resistor element. and Display (516), the display being configured to present a graphical representation of the resistive braking capacity of the resistor grid relative to the power capacity difference.

2. The system of claim 1, wherein the power capacity difference is between the peak power capacity and the continuous power capacity.

3. The system according to claim 1 or 2, the system further comprising a second temperature sensor (518) configured to measure the temperature of ambient air, wherein the control circuit (500) is further configured to determine the resistive braking capacity of the resistor grid based on the measured temperature of the ambient air.

4. The system of claim 2, wherein the control circuit (500) is further configured to determine the continuous resistive capacity of the resistor grid based on at least one of the measured temperature of the ambient air and / or the density of the ambient air, and The display (516) is also configured to present a graphical representation of the continuous resistivity of the resistor grid relative to the capacity difference.

5. The system according to claim 2 or 4, wherein the control circuit (500) is configured to: determine the temperature change of at least one of the plurality of resistor elements (410); and update the graphical representation of the resistive braking capacity according to the temperature change of the at least one resistor element.

6. The system according to any one of claims 1 to 5, wherein the graphical representation includes a first indication of peak power capacity, a second indication of continuous power capacity, and a third indication of the resistive braking capacity relative to the first and second indications.

7. The system according to any one of claims 1 to 6, wherein the graphical representation comprises a bar graph including the peak power capacity at a first end and the continuous power capacity at a second end, wherein a first portion of the first end is colored with a first color and a second portion of the second end is colored with a second color, and wherein the third indication comprises a line indicating the positioning of the resistive braking capacity relative to the first end and the second end.

8. A method (600) for controlling an electrically driven machine, the method (600) comprising: The temperature (610) of the resistor element of the resistor grid that is electrically coupled to the motor of the electrically driven machine is determined by one or more processors. The resistive braking capacity (620) of the resistor grid within the power capacity difference is determined by the one or more processors based on the determined temperature of the resistor element. as well as The one or more processors present a graphical representation (630) of the resistive braking capacity of the resistor grid relative to the power capacity difference on the display of the electrically driven machine.

9. The method (600) of claim 8, wherein the power capacity difference is between the peak power capacity and the continuous power capacity.

10. The method (600) according to claim 9, further comprising: The ambient air temperature (640) is determined by the one or more processors. as well as The peak power capacity (650) of the power capacity difference is determined by the one or more processors based on the ambient air temperature.

11. The method (600) of claim 10, further comprising determining the ambient air density by the one or more processors, wherein the determination of the peak power capacity is based on the ambient air temperature and the ambient air density.

12. The method (600) according to claim 11, further comprising: The one or more processors determine the continuous resistive capacity of the power capacity difference based on at least one of the ambient air temperature and the ambient air density; as well as The continuous resistive capacity is displayed to the operator of the electrically driven machine.

13. The method (600) according to any one of claims 8 to 12, the method further comprising: The temperature change of the resistor element is determined by the one or more processors; as well as The graphical representation of the resistive braking capacity is updated by the one or more processors based on the change in temperature.

14. The method (600) according to any one of claims 8 to 13, wherein the graphical representation includes a first indication of peak power capacity, a second indication of continuous power capacity, and a third indication of the resistive braking capacity relative to the first and second indications.

15. The method (600) of any one of claims 8 to 14, wherein the graphical representation comprises a bar graph including the peak power capacity at a first end and the continuous power capacity at a second end, wherein a first portion of the first end is colored with a first color and a second portion of the second end is colored with a second color, and wherein the third indication comprises a line indicating the positioning of the resistive braking capacity relative to the first end and the second end.

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