Heat dissipation method and heat dissipation device for train braking resistor

Abstract

The present invention provides a heat dissipation method, heat dissipation device, and corresponding computer-readable storage medium for a train brake resistor. The heat dissipation method for a train brake resistor includes the following steps: determining a first upper limit for the operation of the brake resistor without heat dissipation, and a second upper limit for the operation of the brake resistor without heat dissipation, and a second upper limit for the operation of the brake resistor after the brake resistor stops operating; monitoring the bus voltage across the brake resistor; in response to the bus voltage reaching a preset first voltage threshold, calculating the operation time of the brake resistor for the bus voltage to fall back to a preset second voltage threshold; in response to the resistance operation time reaching the first upper limit, turning on a fan to dissipate heat for the brake resistor, and monitoring the train's travel speed; in response to the travel speed being less than or equal to a preset speed threshold, determining whether the resistance operation time has reached the second upper limit; and in response to the determination that the resistance operation time has reached the second upper limit, keeping the fan on.

Description

Technical Field

[0001] The present invention relates to a heat dissipation technology for a train brake resistor, and in particular to a heat dissipation method for a train brake resistor and a heat dissipation device for a train brake resistor. Background Art

[0002] Currently, most urban rail transit traction systems are equipped with brake resistors, which are primarily responsible for absorbing overvoltages in the main circuit and braking chopping energy. Currently, in the existing technology in this field, when the pantograph-catenary voltage reaches a certain value, the circuit absorbs the electric braking energy in the form of heat through the brake resistor. However, due to the extremely high heat generated by the brake resistor, a high-volume fan is required to dissipate the heat, and the air duct is open to the outside, resulting in high noise levels from the brake resistor. Furthermore, to minimize the heat generated by the brake resistor, the brake resistor fan is always on. This results in high noise levels when passengers get on and off the platform. To avoid this noise, if the fan is stopped during stops, the heat dissipation conditions of the brake resistor will deteriorate, potentially leading to overheating. Furthermore, the high number of stops each day causes the brake resistor fan contactor to close and open hundreds of times, significantly shortening its lifespan. The fan's lifespan is also significantly shortened by the frequent starts and stops.

[0003] In order to overcome the above-mentioned defects of the prior art, the art urgently needs a heat dissipation method for train brake resistors, which can be used to significantly reduce the energy consumption of the resistor fan, reduce the number of fan starts and stops, and ensure the heat dissipation of the brake resistor under maximum load conditions. Summary of the Invention

[0004] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a heat dissipation method for a train brake resistor, which can significantly reduce the energy consumption of the resistor fan, reduce the number of fan starts and stops, and ensure the heat dissipation of the brake resistor under maximum load conditions.

[0006] Specifically, the heat dissipation method for a train brake resistor provided according to the first aspect of the present invention includes the following steps: determining a first time limit for the brake resistor to operate without heat dissipation, and a second time limit for turning off the heat dissipation after stopping operation; monitoring the bus voltage at both ends of the brake resistor; in response to the bus voltage reaching a preset first voltage threshold, counting the resistor operation time consumed by the bus voltage to drop back to a preset second voltage threshold; in response to the resistor operation time reaching the first time limit, turning on the fan to dissipate heat for the brake resistor, and monitoring the travel speed of the train; in response to the travel speed being less than or equal to a preset speed threshold, judging whether the resistor operation time has reached the second time limit; and in response to the judgment result that the resistor operation time has reached the second time limit, keeping the fan turned on.

[0007] Furthermore, in some embodiments of the present invention, the above-mentioned heat dissipation method also includes the following steps: in response to a judgment result that the driving speed is less than or equal to the speed threshold and the resistor operating time has not reached the second time upper limit, turning off the fan, and after the resistor operating time reaches the second time upper limit, turning on the fan again to dissipate heat for the brake resistor.

[0008] Furthermore, in some embodiments of the present invention, the heat dissipation method further includes the following steps:

[0009] In response to a judgment result that the resistance operation time exceeds the preset time or a judgment result that the resistance operation time reaches the second time upper limit and only one start-stop process is included in the preset time, the resistance operation time is reset to zero until the bus voltage reaches the first voltage threshold again, and then the resistance operation time consumed for the bus voltage to fall back to the second voltage threshold is re-counted; and in response to a judgment result that the resistance operation time reaches the second time upper limit and does not exceed the preset time and at least two start-stop processes are included in the preset time, the resistance operation time is continued to be counted.

[0010] Furthermore, in some embodiments of the present invention, the step of determining a first time limit for the braking resistor to operate without heat dissipation, and a second time limit for turning off heat dissipation after stopping operation includes: performing an operation experiment on the braking resistor without heat dissipation, and calibrating the first time limit according to the time when the braking resistor is overheated and damaged; and / or controlling the braking resistor to operate under a condition of fan heat dissipation, turning off the fan when the braking resistor stops operating, and calibrating the second time limit according to the time when the braking resistor is overheated and damaged.

[0011] Furthermore, in some embodiments of the present invention, the first voltage threshold is determined based on the upper voltage limit of the traction converter and / or pantograph network of the train, and the second voltage threshold is determined based on the normal operating voltage of the bus voltage.

[0012] Furthermore, in some embodiments of the present invention, both ends of the braking resistor are connected to the bow network of the train via a chopping unit, wherein the bus voltage of the bow network rises when the train brakes, and the chopping unit operates in response to the bus voltage reaching the first voltage threshold, controlling the braking resistor to absorb energy and generate heat to reduce the bus voltage, and the chopping unit is also shut down in response to the bus voltage falling back to the second voltage threshold to stop operating the braking resistor.

[0013] Furthermore, in some embodiments of the present invention, the speed threshold indicates a parking condition.

[0014] In addition, the heat dissipation device for a train braking resistor provided according to the second aspect of the present invention includes: a fan facing the braking resistor, for dissipating heat for the braking resistor; a memory, for storing computer instructions; and a processor, wherein the processor is connected to the memory and is configured to execute the computer instructions stored in the memory to implement the heat dissipation method for a train braking resistor as described in any one of claims 1 to 7.

[0015] Furthermore, in some embodiments of the present invention, the fan is connected to its power supply via a contactor, wherein the processor closes the contactor to turn on the fan to dissipate heat for the braking resistor, and the processor also disconnects the contactor to turn off the fan.

[0016] Furthermore, the computer-readable storage medium provided in accordance with the third aspect of the present invention stores computer instructions, which, when executed by a processor, implement the train brake resistor heat dissipation method provided in accordance with the first aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above features and advantages of the present invention will be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or characteristics may have the same or similar reference numerals.

[0018] Figure 1 A schematic diagram of the installation position of a brake resistor according to some embodiments of the present invention is shown.

[0019] Figure 2 A schematic diagram of power supply to a braking resistor according to some embodiments of the present invention is shown.

[0020] Figure 3 A schematic diagram of a heat dissipation method for a brake resistor provided according to some embodiments of the present invention is shown. DETAILED DESCRIPTION

[0021] The following specific embodiments illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiment is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0023] Furthermore, the terms "upper," "lower," "left," "right," "top," "bottom," "horizontal," and "vertical" used in the following description should be understood to refer to the orientations depicted in that section and the accompanying drawings. These relative terms are used solely for convenience of description and do not necessarily imply that the devices described herein must be manufactured or operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0024] It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe various components, regions, layers, and / or portions, these components, regions, layers, and / or portions should not be limited by these terms, and these terms are merely used to distinguish different components, regions, layers, and / or portions. Thus, a first component, region, layer, and / or portion discussed below may be referred to as a second component, region, layer, and / or portion without departing from some embodiments of the present invention.

[0025] As mentioned above, most traction systems in urban rail transit are currently equipped with brake resistors, which are primarily responsible for absorbing overvoltage in the main circuit and braking chopping energy. Currently, in the existing technology in this field, when the pantograph-net voltage reaches a certain value, the circuit absorbs the electric braking energy in the form of heat through the brake resistor. However, due to the extremely high heat generated by the brake resistor, a high-volume fan is required to dissipate the heat, and the air duct is open to the outside, resulting in relatively loud noise from the brake resistor. In addition, to minimize the heat generated by the brake resistor, the brake resistor fan is always on. This results in loud noise when passengers get on and off the platform. To avoid noise, if the fan is stopped during stops, the heat dissipation conditions of the brake resistor will deteriorate, potentially leading to overheating. In addition, the large number of stops each day will cause the brake resistor fan contactor to close and open hundreds of times, significantly shortening its lifespan. The fan lifespan is also significantly shortened due to the frequent starts and stops.

[0026] In order to overcome the above-mentioned defects in the prior art, the present invention provides a heat dissipation method for a brake resistor, which is used to significantly reduce the energy consumption of the resistor fan, reduce the number of fan starts and stops, and ensure the heat dissipation of the brake resistor under maximum load conditions.

[0027] In some non-limiting embodiments, the heat dissipation device for a train brake resistor provided in the second aspect of the present invention comprises a memory and a processor. The memory includes, but is not limited to, the computer-readable storage medium provided in the third aspect of the present invention, which stores computer instructions. The processor is connected to the memory and configured to execute the computer instructions stored in the memory to implement the heat dissipation method for a train brake resistor provided in the first aspect of the present invention.

[0028] First, please refer to Figure 1 . Figure 1 A schematic diagram of the installation position of a brake resistor according to some embodiments of the present invention is shown.

[0029] like Figure 1As shown, under braking conditions, the train is controlled by a VVVF inverter (inverter unit) motor. At this time, the motor operates in a power generation state to provide electric braking force for the train. At the same time, when the motor operates in a power generation state, the output electricity is fed back to the power grid via the VVVF inverter unit. When the power grid cannot absorb the output electricity, the electric braking energy will raise the bow-net voltage according to the inherent characteristics of the power grid. When the bow-net voltage reaches DC1850V (normal value), the VVVF inverter (chopper unit) turns on and absorbs the electric braking energy in the form of heat through the braking resistor. Here, the heat dissipation device for the train braking resistor provided in the second aspect of the present invention may include a fan, a memory and a processor. The fan can be installed above or to the side of the braking resistors R1 and R2, and the memory is connected through the processor in the heat dissipation device to execute the heat dissipation method for the braking resistor provided in the second aspect of the present invention to ensure the heat dissipation of the braking resistor under maximum load conditions.

[0030] Those skilled in the art will understand that the above-mentioned embodiments in which the fan is installed above or to the side of the brake resistor are merely some non-limiting implementation methods provided by the present invention, which are intended to clearly demonstrate the main concepts of the present invention and provide some specific solutions that are convenient for the public to implement, rather than to limit all functions or all working modes of the fan.

[0031] Specifically, the fan can be connected to a power source via a contactor. The processor can be controlled by the heat dissipation method for a train brake resistor provided by the second aspect of the present invention, closing the contactor to start the fan to dissipate heat for the brake resistor, or opening the contactor to stop the fan from dissipating heat for the brake resistor.

[0032] The following describes the heat dissipation device for a train brake resistor in conjunction with some examples of heat dissipation methods for train brake resistors. Those skilled in the art will understand that these examples of heat dissipation methods for train brake resistors are merely non-limiting implementations of the present invention, intended to clearly demonstrate the main concepts of the present invention and provide specific solutions that are convenient for the public to implement. They are not intended to limit the full functionality or operating modes of the heat dissipation device for a train brake resistor. Similarly, the heat dissipation device for a train brake resistor is merely a non-limiting implementation of the present invention and does not limit the execution of the various steps in the heat dissipation methods for train brake resistors.

[0033] Please refer to Figure 1 、 Figure 2 as well as Figure 3 . Figure 2 A schematic diagram of power supply to a braking resistor according to some embodiments of the present invention is shown. Figure 3 A schematic diagram of a heat dissipation method for a brake resistor provided according to some embodiments of the present invention is shown.

[0034] like Figure 1 、 Figure 2 as well as Figure 3 As shown, during the train braking process, the processor can first determine a first upper limit for the braking resistor to operate without heat dissipation, and a second upper limit for the time it takes to shut down the heat dissipation after the train stops operating. Specifically, a person skilled in the art can conduct a running experiment with the braking resistor without heat dissipation and calibrate the first upper limit based on the time it takes for the braking resistor to overheat and damage. A person skilled in the art can also control the braking resistor to operate with a fan for heat dissipation, shut down the fan when the braking resistor stops operating, and calibrate the second upper limit based on the time it takes for the braking resistor to overheat and damage. After determining the first and second upper limits, the processor can monitor the bus voltage across the braking circuit. When the bus voltage reaches a preset first voltage threshold, the processor calculates the time it takes for the bus voltage to fall back to a preset second voltage threshold. Specifically, the first voltage threshold can be determined based on the upper voltage withstand limits of the train's traction converter and pantograph. The first voltage threshold can be a commonly used power grid value of DC1850V. The second voltage threshold can be determined based on the normal operating voltage of the bus voltage, which can be a commonly used value of 1750V. After determining the bus voltage across the braking resistor, in response to the bus voltage reaching the first voltage threshold, the processor can calculate the resistor operating time t it takes for the bus voltage to fall back to the second voltage threshold. Subsequently, when the braking resistor operating time t reaches the first time limit t1, the processor can turn on the fan to dissipate heat from the braking resistor while simultaneously monitoring the train's speed. When the train's speed is less than or equal to a preset speed threshold, the processor can determine whether the braking resistor operating time has reached the second time limit. When the resistor operating time reaches the second time limit, the processor can keep the fan on. In this way, the present invention can keep the fan on even when the train speed decreases to a stop condition. Compared to current control schemes that turn the fan off each time the train stops and on each time the train starts, the present invention can reduce the number of fan starts and stops, ensure heat dissipation from the braking resistor under maximum load conditions, and significantly reduce the energy consumption of the resistor fan.

[0035] Furthermore, in some embodiments of the present invention, during the train braking process, when the train speed is less than or equal to the speed threshold and the braking resistor operating time has not reached the second time limit t2, the processor may determine that the train does not need to activate the fan to prevent the resistor from overheating, and thus shut down the fan. When the braking resistor operating time reaches the second time limit t2, the processor may determine that the braking resistor requires activation of the fan to dissipate heat to prevent overheating during train operation, and thus restart the fan to dissipate heat for the braking resistor. Here, the speed threshold may be a train speed close to that of a stopped train to represent a stopped train condition.

[0036] Furthermore, during the train's travel, the duration of the train's normal start-stop process can be used as a preset time t4. When the resistor operation time t reaches the second time limit t2 (i.e., t>t2) and the preset time t4 includes only one start-stop process (i.e., the time period t4 only includes t1 and does not include t3), the processor can determine that the train has only started and stopped once within the normal start-stop period, thereby determining that the train is under normal operating conditions, and reset the resistor operation time until the bus voltage reaches the first voltage threshold again, and then recalculate the resistor operation time t it takes for the bus voltage to fall back to the second voltage threshold. Here, the preset time t4 can be determined by the duration of the train's normal start-stop process, and t3 indicates the first time limit for the train's brake resistor to operate without heat dissipation during the second start-stop process. In this way, this method can ensure that under normal train operation, the energy consumption of the brake fan is significantly reduced, the number of fan starts and stops is reduced, and the heat dissipation of the brake resistor is guaranteed under maximum load conditions.

[0037] Alternatively, in other embodiments, in response to the determination that the resistor operating time t reaches the second time limit t2 and does not exceed the preset time t4, and that at least two start-stop processes occur within the preset time t4, the processor may determine that the train is in a fault or debugging period, thereby continuing to count the resistor operating time and repeating the above method to start / stop the fan during each start-stop cycle of the train. In this way, this method can significantly reduce the energy consumption of the resistor fan and the number of fan starts and stops under fault / debugging conditions, while also ensuring heat dissipation of the brake resistor under maximum load conditions.

[0038] In summary, by implementing the above-mentioned control scheme for starting and stopping the fan, the present invention can stop the fan under normal / fault / debugging conditions when the braking resistor can dissipate heat by itself to avoid overheating of the braking resistor, thereby significantly reducing the energy consumption of the resistor fan and reducing its noise impact on passengers. It can also keep the fan running continuously when the braking resistor cannot dissipate heat by itself, thereby reducing the number of times the fan is started and stopped and extending its life.

[0039] Furthermore, in some embodiments of the present invention, the two ends of the braking resistor may be connected to the train's pantograph network via a chopper unit. Here, the bus voltage of the pantograph network increases when the train brakes. When the bus voltage reaches the first voltage threshold, the processor may control the chopper unit to operate. The processor may also control the braking resistor to absorb energy and generate heat to reduce the bus voltage. When the bus voltage drops back to the second voltage threshold, the processor may control the chopper unit to stop operating the braking resistor.

[0040] Although the above methods are illustrated and described as a series of acts for simplicity of explanation, it is to be understood and appreciated that these methods are not limited by the order of the acts, as some acts may occur in a different order and / or concurrently with other acts from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art according to one or more embodiments.

[0041] Those skilled in the art will appreciate that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips cited throughout the foregoing description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0042] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. A skilled person may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0043] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be 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, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0044] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A heat dissipation method for a train braking resistor, characterized in that: The following steps are involved: Performing a non-heat-dissipating operation experiment on the braking resistor, and calibrating a first time limit according to the time when the braking resistor is damaged by overheating; and / or controlling the braking resistor to operate under a condition where a fan dissipates heat, shutting down the fan when the braking resistor stops operating, and calibrating a second time limit according to a time when the braking resistor is damaged by overheating; monitoring the bus voltage across the braking resistor; In response to the bus voltage reaching a preset first voltage threshold, counting the resistance operation time consumed for the bus voltage to fall back to a preset second voltage threshold; In response to the resistor operation time reaching the first time limit, turning on a fan to dissipate heat for the brake resistor, and monitoring the running speed of the train; In response to the driving speed being less than or equal to a preset speed threshold, determining whether the resistance operation time reaches the second time upper limit; In response to a determination result that the driving speed is less than or equal to the speed threshold and the resistor operation time has not reached the second time limit, turning off the fan, and turning on the fan again to dissipate heat from the brake resistor after the resistor operation time reaches the second time limit; as well as In response to a determination that the resistance operation time reaches the second time upper limit, the fan is kept turned on.

2. The heat dissipation method according to claim 1, wherein: The following steps are also included: In response to a determination result that the resistance operation time exceeds a preset time or that the resistance operation time reaches the second time upper limit and a determination result that the preset time includes only one start-stop process, the resistance operation time is reset to zero until the bus voltage reaches the first voltage threshold again, and then the resistance operation time consumed for the bus voltage to fall back to the second voltage threshold is recalculated; as well as In response to a judgment result that the resistance operation time reaches the second time upper limit and does not exceed the preset time and includes at least two start-stop processes within the preset time, the resistance operation time continues to be counted.

3. The heat dissipation method according to claim 1, wherein: The first voltage threshold is determined according to the upper voltage limit of the traction converter and / or the pantograph network of the train, and the second voltage threshold is determined according to the normal operating voltage of the bus voltage.

4. The heat dissipation method according to claim 1 or 3, characterized in that: The two ends of the braking resistor are connected to the pantograph of the train via a chopper unit, wherein the bus voltage of the pantograph increases when the train brakes. The chopper unit operates in response to the bus voltage reaching the first voltage threshold, controlling the braking resistor to absorb energy and generate heat to reduce the bus voltage. The chopper unit is further turned off in response to the bus voltage falling back to the second voltage threshold to stop operating the braking resistor.

5. The heat dissipation method according to claim 1, wherein: The speed threshold is indicative of a parking condition.

6. A heat dissipation device for a train braking resistor, characterized in that: include: A fan, facing the braking resistor, for dissipating heat from the braking resistor; Memory, for storing computer instructions; as well as A processor, wherein the processor is connected to the memory and is configured to execute computer instructions stored in the memory to implement the heat dissipation method for a train braking resistor according to any one of claims 1 to 5.

7. The heat dissipation device according to claim 6, characterized in that: The fan is connected to a power supply via a contactor, wherein the processor closes the contactor to turn on the fan to dissipate heat for the brake resistor, and the processor also opens the contactor to turn off the fan.

8. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by the processor, the heat dissipation method for a train brake resistor according to any one of claims 1 to 5 is implemented.

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