Bus temperature control method and system for wide-temperature-range catenary servo vibration test

Abstract

The invention relates to the technical field of railway catenary part simulation tests, in particular to a bus temperature control method and system for a wide-temperature-range catenary servo vibration test, and is applied to a multi-servo-node cascade bus topology system for the catenary servo vibration test. The method comprises the steps that environment temperature data and communication cable temperature data of a test site are collected in real time; dynamically setting a cable temperature control interval based on the environment temperature data; and when the temperature data of the communication cable exceeds the temperature control interval, the positive temperature coefficient heating sheet and the thermoelectric refrigeration sheet are driven to execute temperature adjustment. According to the invention, the temperature control interval dynamically fluctuates along with the ambient temperature, and the problems of differential signal amplitude attenuation and sharp bit error rate increase at high temperature caused by cable resistance temperature drift and the problem of fast temperature change impedance mismatch can be solved by dynamically matching the change trend of cable resistance with the ambient temperature; no-distortion or low-distortion synchronous reproduction of multi-servo-node complex vibration waveforms can be ensured, and it is ensured that test waveforms determined by high manpower cost are accurately achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of simulation test technology of railway catenary parts, and in particular to a bus temperature control method and system for wide-temperature-range catenary servo vibration test. BACKGROUND

[0002] At present, the simulation vibration test of catenary parts of electrified railway is carried out at room temperature, and two electric cylinders are used to load the catenary in the vertical direction and the horizontal direction respectively. However, the current test conditions are quite different from the actual working conditions of the railway site, on the one hand, the difference in temperature, on the other hand, the difference between the vibration power provided by the power source and the actual stress of the catenary.

[0003] In order to solve the above problems, the test system is expanded to a three or more servo node cascade bus topology, each servo node is connected in series through a cable to form a signal transmission chain, each node receives the previous signal, processes the control instruction and regenerates a digital signal, and forwards it to the next node. Through the above comprehensive and complex waveforms provided by the multi-servo node, the relatively complex actual vibration state is restored as much as possible, and the temperature difference from minus 30 DEG C to plus 50 DEG C is simulated. In order to enrich the test conditions, the temperature in the simulated environment changes at a high rate during the test process.

[0004] Under the above wide-temperature-range test conditions, the communication stability of the multi-servo system will have the following problems due to the temperature difference: the differential signal amplitude attenuation caused by the cable resistance temperature drift, the high temperature error rate surge, in the simulation vibration test, the multi-servo system needs to transmit synchronous instructions in real time, and such error will directly cause waveform distortion; the waveform of the multi-servo system often needs to be collected on site, and the waveform is confirmed through a relatively complex simulation, and the above distorted situation seriously restricts the authenticity of the vibration reproduction, and the labor cost is wasted. SUMMARY

[0005] The present application provides a bus temperature control method and system for wide-temperature-range catenary servo vibration test, which can effectively solve the problems in the background art.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is: The bus temperature control method for wide-temperature-range catenary servo vibration test is applied to a multi-servo node cascade bus topology system for catenary servo vibration test, the distance between two adjacent servo nodes is less than a set value, and the two adjacent servo nodes are connected through a segmented constant temperature cable; The outer layer of the segmented constant temperature cable is a metal heat conducting layer, and the inner layer is a communication cable in which positive temperature coefficient heating sheets and thermoelectric refrigeration sheets are installed, and the inner layer and the outer layer are separated by an aerogel thermal insulation layer; The bus temperature control method comprises: Collecting environmental temperature data and the communication cable temperature data in real time; Setting a cable temperature control interval dynamically based on the environmental temperature data; Driving the positive temperature coefficient heating sheet and the thermoelectric refrigeration sheet to perform temperature adjustment when the communication cable temperature data exceeds the temperature control interval.

[0007] Further, the bus temperature control method of the wide-temperature-range catenary servo vibration test comprises: When the communication cable temperature data is lower than the lower limit of the temperature control interval, the positive temperature coefficient heating sheet is started, and the power heating is stepped up; Wherein, the power decreases by 15% to 25% for each 1℃ increase, until the temperature reaches 0.5℃ to 1℃ above the lower limit of the temperature control interval, and the temperature control mode is switched to constant temperature mode.

[0008] Further, the bus temperature control method of the wide-temperature-range catenary servo vibration test comprises: When the communication cable temperature data is higher than the upper limit of the temperature control interval, the thermoelectric refrigeration sheet is started, and the adjacent segment of the segmented constant-temperature cable is controlled in parallel to form a heat conduction path.

[0009] Further, starting the thermoelectric refrigeration sheet and controlling the adjacent segmented constant-temperature cable in parallel to form a heat conduction path comprises: Starting the thermoelectric refrigeration sheet in the current segment to refrigerate, and the positive temperature coefficient heating sheet in the adjacent segmented constant-temperature cable to heat, and the heating heat is blocked by the peripheral aerogel thermal insulation layer.

[0010] Further, the inner surface of the metal heat-conducting layer is compounded with phase change heat storage material with a melting point of 45℃±2℃, the hot end of the thermoelectric refrigeration sheet is welded with aluminum heat dissipation fins, and the fins penetrate the aerogel thermal insulation layer; When the cold end of the thermoelectric refrigeration sheet refrigerates and the temperature of the hot end rises to the melting point, the liquid phase change heat storage material flows to the relatively low temperature area to solidify and release heat under the action of capillary force.

[0011] Further, the communication cable comprises, from inside to outside, a conductor layer, an insulating layer, and a metal shielding layer; Collecting the communication cable temperature data in real time comprises: Segmented platinum resistance temperature sensors are installed between the insulating layer and the metal shielding layer; the signals of the platinum resistance temperature sensors are connected to the ADC acquisition channel of the distributed temperature control module through the twisted pair shielding line located in the conductor layer.

[0012] Further, the set value of the distance between adjacent two servo nodes is 2 meters, and the distance between adjacent two platinum resistance temperature sensors is 0.15 to 0.2 meters.

[0013] Further, the positive temperature coefficient heating sheet is arranged in a strip shape along the length direction of the cable, is attached to the surface of the metal shielding layer, and a surface is covered with insulating and heat-conducting silica gel.

[0014] Further, the thermoelectric refrigeration sheet and the positive temperature coefficient heating sheet are arranged alternately on the surface of the metal shielding layer. The cold end of the thermoelectric refrigeration sheet is attached to the metal shielding layer, and the hot end is welded with an aluminum heat dissipation fin, and the fin penetrates the aerogel thermal insulation layer.

[0015] The temperature control bus communication system for the wide-temperature-range catenary servo vibration test is applied to a multi-servo node cascade bus topology system for the catenary servo vibration test, and comprises: The segmented constant-temperature cable is connected between two adjacent servo nodes and has a length less than a set value, the outer layer of the segmented constant-temperature cable is a metal heat-conducting layer, the inner layer is a communication cable on which a positive temperature coefficient heating sheet and a thermoelectric refrigeration sheet are mounted, and the inner layer and the outer layer are separated by an aerogel thermal insulation layer; The temperature acquisition module acquires environmental temperature data and communication cable temperature data of a test site in real time; The temperature control decision module dynamically sets a cable temperature control interval based on the environmental temperature data; The temperature control execution module drives the positive temperature coefficient heating sheet and the thermoelectric refrigeration sheet to perform temperature adjustment when the communication cable temperature data exceeds the temperature control interval.

[0016] The technical scheme of the present application can achieve the following technical effects: In the present application, the temperature control interval fluctuates dynamically with the environmental temperature, the change trend of the cable resistance can be dynamically matched with the environmental temperature, the problems of differential signal amplitude attenuation caused by cable resistance temperature drift, a sharp increase in bit error rate at high temperature, and fast temperature change impedance mismatch can be solved, the complex vibration waveform of the multi-servo node can be reproduced synchronously without distortion or with low distortion, and the test waveform determined by high labor cost can be accurately implemented. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 It is a multi-servo node cascade bus topology system framework diagram; Figure 2 It is a bus temperature control method flowchart for the wide-temperature-range catenary servo vibration test. Figure 3 A schematic diagram of a bus temperature control system for a wide-temperature-range contact network servo vibration test. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0020] like Figure 1 As shown, the bus temperature control method for wide-temperature-range catenary servo vibration test is applied to a multi-servo node cascaded bus topology system for catenary servo vibration test. The distance between two adjacent servo nodes is less than a set value, and they are connected by segmented constant temperature cables.

[0021] In this embodiment, the outer layer of the segmented constant temperature cable is a metal heat-conducting layer, and the inner layer is a communication cable with a positive temperature coefficient heating element and a thermoelectric cooling element installed. The inner and outer layers are separated by an aerogel heat insulation layer. By limiting the distance between adjacent servo nodes, that is, limiting the length of a single segmented constant temperature cable, the high-temperature error chain reaction can be blocked by controlling the differential signal attenuation rate.

[0022] like Figure 2 As shown, based on the above segmented constant temperature cable, the bus temperature control method includes: A1: Real-time acquisition of ambient temperature data and communication cable temperature data of the test site; A2: The cable temperature control range is dynamically set based on ambient temperature data. In this embodiment, the temperature control range can be specifically the ambient temperature ±5℃. A3: When the temperature data of the communication cable exceeds the temperature control range, the positive temperature coefficient heating element and thermoelectric cooling element are driven to perform temperature regulation.

[0023] In this invention, the temperature control range fluctuates dynamically with the ambient temperature. By dynamically matching the trend of cable resistance change with the ambient temperature, the problems of differential signal amplitude attenuation caused by cable resistance temperature drift, bit error rate surge at high temperatures, and impedance mismatch due to rapid temperature change can be solved.

[0024] In the implementation process, taking the temperature from 25°C to 50°C as an example, the segmented constant temperature cable temperature can be synchronized to the interval of 45°C to 55°C by the application, the conductor resistance increment is limited, the skin effect of the cable metal shielding layer is optimized, the signal attenuation is controllable, and the problem of the error code rate surge is improved. In addition, taking a 5°C / min temperature change environment as an example, the application can control the real-time temperature difference between the cable and the environment, avoid the sheath micro-cracking and impedance mutation caused by short-time high temperature difference in the traditional fixed temperature control scheme, eliminate sudden error codes from the physical layer, ensure the distortionless or low-distortion synchronous reproduction of complex vibration waveforms of multiple servo nodes, and ensure that the test waveforms determined by high labor cost are accurately implemented.

[0025] As a preferred embodiment of the above example, the low-temperature state is optimized, and when the communication cable temperature data is lower than the lower limit of the temperature control interval, the positive temperature coefficient heating sheet is started, and the power heating is stepped up. Wherein, the power decreases by 15% to 25% per 1°C, and when the temperature reaches 0.5°C to 1°C above the lower limit of the temperature control interval, it is switched to a constant temperature mode.

[0026] In this preferred embodiment, the step-up power mode combined with the constant temperature switching mechanism can avoid the overshoot problem of the positive temperature coefficient heating sheet. In this preferred embodiment, the temperature feedback dynamically reduces the power, so that the temperature curve converges smoothly to the target interval.

[0027] As another aspect of temperature regulation, the high-temperature state is optimized, and when the communication cable temperature data is higher than the upper limit of the temperature control interval, the thermoelectric refrigeration sheet is started, and the adjacent segmented constant temperature cables are controlled in parallel to form a heat conduction path.

[0028] This preferred embodiment aims to solve the risk of local heat accumulation failure of the thermoelectric refrigeration sheet. In the implementation process, when a single thermoelectric refrigeration sheet cools, the temperature of the hot end rises, causing the cooling efficiency to decay. In this preferred embodiment, the adjacent segmented constant temperature cables are linked to perform temperature control, and the heat is diffused to the entire system through the metal heat conduction layer, so that the temperature of the hot end of the thermoelectric refrigeration sheet is stabilized below the set temperature; for example, in a +45°C high temperature working condition, the linked control mode improves the cooling response speed.

[0029] As a preferred embodiment of the above example, the thermoelectric refrigeration sheet is started, and the adjacent segmented constant temperature cables are controlled in parallel to form a heat conduction path, comprising: Starting the current segment thermoelectric refrigeration sheet to cool, and the positive temperature coefficient heating sheet in the adjacent segmented constant temperature cable to heat the communication cable, and the heating heat is blocked by the peripheral aerogel thermal insulation layer.

[0030] In the working process of the thermoelectric refrigeration sheet, the heat of the hot end needs to be dissipated. In the preferred embodiment, when the adjacent section of the communication cable is heated, the metal heat conduction layer of the adjacent section is maintained at a relatively low temperature due to the aerogel thermal insulation, forming a relatively stable temperature difference with the hot end of the thermoelectric refrigeration sheet. The waste heat is driven from the high-temperature area of the hot end of the thermoelectric refrigeration sheet to the metal heat conduction layer of the adjacent section in a one-way manner, solving the problem of heat accumulation in the traditional scheme.

[0031] In implementation, for the segmented constant temperature cable of the adjacent section, the metal heat conduction layer absorbs heat at low temperature, while the inner layer compensates for thermal inertia fluctuations to prevent micro-cracks caused by a large temperature difference between the inner layer and the peripheral metal heat conduction layer, thereby ensuring the mechanical integrity of the cable. Of course, the heating power of the adjacent section needs to be controlled, which can be specifically positively correlated with the temperature difference between the metal heat conduction layers of the current section and the adjacent section.

[0032] As a further preferred embodiment of the above embodiment, the metal heat conduction layer is coated with a phase change heat storage material with a melting point of 45℃±2℃, and the hot end of the thermoelectric refrigeration sheet is welded with an aluminum heat dissipation fin that penetrates the aerogel thermal insulation layer. When the cold end of the thermoelectric refrigeration sheet is refrigerated and the temperature of the hot end rises to the melting point, the liquid phase change heat storage material flows to the relatively low temperature area under the action of capillary force and solidifies to release heat.

[0033] The metal heat conduction layer forms a capillary network after processing. In this embodiment, a paraffin-based composite phase change material can be used, which has the characteristic of quickly absorbing heat dissipated by the hot end of the thermoelectric refrigeration sheet. The aluminum heat dissipation fin penetrates the aerogel thermal insulation layer and directly connects the metal heat conduction layer, establishing a low thermal resistance channel. When the hot end heats up and the phase change material melts into a liquid state, capillary force drives it to flow to the relatively low temperature position that can be reached, and solidification releases latent heat. Embodiment Two

[0034] The same as Embodiment One is: The bus temperature control method for wide temperature range contact network servo vibration test is applied to a multi-servo node cascade bus topology system for contact network servo vibration test. The distance between two adjacent servo nodes is less than a set value, and they are connected by a segmented constant temperature cable. The outer layer of the segmented constant temperature cable is a metal heat conduction layer, and the inner layer is a communication cable with a positive temperature coefficient heating sheet and a thermoelectric refrigeration sheet. The inner layer and the outer layer are separated by an aerogel thermal insulation layer. In this embodiment, by limiting the distance between adjacent servo nodes, the high-temperature error code chain reaction can be blocked by controlling the differential signal attenuation rate. At high temperatures, limiting the length of a single cable ensures the signal amplitude attenuation rate between two servo nodes. The specific steps of the bus temperature control method include: Real-time acquisition of environmental temperature data and communication cable temperature data of the test site; based on the environmental temperature data, the cable temperature control interval is dynamically set, in this embodiment, the temperature control interval can be specifically the environmental temperature ± 5℃; when the communication cable temperature data exceeds the temperature control interval, the positive temperature coefficient heating sheet and the thermoelectric refrigeration sheet are driven to perform temperature adjustment.

[0035] The technical effects of the above scheme are the same as those of Embodiment One, except that in this embodiment, as a further optimization, the communication cable comprises, from the inside out, a conductor layer, an insulating layer and a metal shielding layer; real-time acquisition of communication cable temperature data, including: The platinum resistance temperature sensor is installed between the insulating layer and the metal shielding layer in sections; the signal of the platinum resistance temperature sensor is connected to the ADC acquisition channel of the distributed temperature control module through the twisted pair shielding line located in the conductor layer.

[0036] In this preferred scheme, the twisted pair shielding line uses the twisted structure to offset the common mode electromagnetic interference, and the metal shielding layer blocks external electric field coupling to eliminate signal noise caused by servo drive pulses and strong current of the catenary; the conductor layer inside the wiring shell avoids impedance loss of long-distance analog signal transmission, and the ADC acquisition channel is localized to realize signal synchronous digitization, so that the temperature quantization error can be reduced in this way. In the embodiments of the present application, the platinum resistance sensor directly contacts the interface between the insulating layer and the metal shielding layer, and the shell accurately captures the real temperature of the cable core.

[0037] In specific implementation, the following optimization is set: the set value of the distance between the adjacent two servo nodes is 2 meters, and the distance between the adjacent two platinum resistance temperature sensors is 0.15 to 0.2 meters, i.e. the distance between the adjacent servo nodes is ≤2 meters, so as to ensure that the single cable signal attenuation rate is controllable, and the platinum resistance temperature sensor spacing is controlled, so that the axial temperature gradient during temperature change can be captured more carefully.

[0038] In order to make the positive temperature coefficient heating sheet obtain better technical effects, as a preferred embodiment of the above embodiment, the positive temperature coefficient heating sheet is in a strip shape and is arranged along the length direction of the cable, is attached to the surface of the metal shielding layer, and the surface is covered with insulating heat-conductive silicone. The covering method in this preferred scheme can realize more uniform and gentle heating compared with point heating, and the insulating heat-conductive silicone realizes high-voltage isolation and interface zero-gap heat transfer.

[0039] As a preferred embodiment of the above embodiment, the setting method of the thermoelectric refrigeration sheet and the positive temperature coefficient heating sheet is further optimized, the thermoelectric refrigeration sheet and the positive temperature coefficient heating sheet are staggered on the surface of the metal shielding layer; the cold end of the thermoelectric refrigeration sheet is attached to the metal shielding layer, and the hot end is welded with an aluminum heat dissipation fin, and the fin penetrates the aerogel thermal insulation layer. The thermoelectric refrigeration sheet and the positive temperature coefficient heating sheet are staggered to form a segmented micro-zone temperature control unit; the role of the aluminum heat dissipation fin in this preferred scheme is as described in the above embodiments, which will not be described here. Example 3

[0040] like Figure 3 As shown, the multi-servo node cascaded bus topology system applied to catenary servo vibration testing includes: The segmented constant temperature cable connects two adjacent servo nodes and has a length less than the set value. The outer layer of the segmented constant temperature cable is a metal heat-conducting layer, and the inner layer is a communication cable with a positive temperature coefficient heating element and a thermoelectric cooling element installed. The inner and outer layers are separated by an aerogel heat insulation layer. The temperature acquisition module collects real-time ambient temperature data and communication cable temperature data from the test site. The temperature control decision module dynamically sets the cable temperature control range based on ambient temperature data; The temperature control module drives the positive temperature coefficient heating element and thermoelectric cooling element to perform temperature adjustment when the temperature data of the communication cable exceeds the temperature control range.

[0041] The technical effects achieved in this embodiment are as described in the above embodiments, and will not be repeated here.

[0042] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A bus-based temperature control method for wide-temperature-range catenary servo vibration testing, applied to a multi-servo node cascaded bus topology system for catenary servo vibration testing, characterized in that... The distance between two adjacent servo nodes is less than a set value, and they are connected by segmented constant temperature cables; The segmented constant temperature cable has an outer metal heat-conducting layer and an inner communication cable with a positive temperature coefficient heating element and a thermoelectric cooling element installed. The inner and outer layers are separated by an aerogel heat insulation layer. Bus temperature control methods include: Real-time acquisition of ambient temperature data at the test site and temperature data of the communication cables; The cable temperature control range is dynamically set based on the ambient temperature data. When the temperature data of the communication cable exceeds the temperature control range, the positive temperature coefficient heating element and the thermoelectric cooling element are driven to perform temperature adjustment.

2. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 1, characterized in that, include: When the temperature data of the communication cable is lower than the lower limit of the temperature control range, the positive temperature coefficient heating element is activated, and the power heating is increased in stages. The power decreases by 15% to 25% for every 1°C increase in temperature, until the temperature reaches 0.5°C to 1°C above the lower limit of the temperature control range, at which point it switches to constant temperature mode.

3. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 1, characterized in that, include: When the temperature data of the communication cable is higher than the upper limit of the temperature control range, the thermoelectric cooling element is activated, and the adjacent segments of the segmented constant temperature cable are controlled to form a heat conduction path.

4. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 3, characterized in that, Activating the thermoelectric cooling element and coordinating with adjacent segmented constant-temperature cables to form a heat conduction path includes: The current segment's thermoelectric cooling element is activated for cooling, and the adjacent segment's segmented constant temperature cable's positive temperature coefficient heating element is activated for heating. The heating heat is blocked by the surrounding aerogel insulation layer.

5. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 4, characterized in that, The inner surface of the metal thermal conductive layer is composite with a phase change thermal storage material with a melting point of 45℃±2℃. The hot end of the thermoelectric cooling chip is welded with aluminum heat dissipation fins, which penetrate the aerogel insulation layer. When the cold end of the thermoelectric cooling element is cooled, causing the temperature of the hot end to rise to the melting point, the liquid phase change thermal storage material flows to a relatively low temperature region under the action of capillary force, solidifies, and releases heat.

6. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 1, characterized in that, The communication cable comprises, from the inside out, a conductor layer, an insulation layer, and a metal shielding layer; Real-time acquisition of temperature data from the communication cable, including: A platinum resistance temperature sensor is installed in sections between the insulating layer and the metal shielding layer; The signal from the platinum resistance temperature sensor is connected to the ADC acquisition channel of the distributed temperature control module via a twisted-pair shielded cable located in the conductor layer.

7. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 6, characterized in that, The set value for the distance between two adjacent servo nodes is 2 meters, and the distance between two adjacent platinum resistance temperature sensors is 0.15 to 0.2 meters.

8. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 6, characterized in that, The positive temperature coefficient heating element is arranged in a strip along the length of the cable, attached to the surface of the metal shielding layer, and covered with insulating and thermally conductive silicone.

9. The bus temperature control method for wide-temperature-range contact network servo vibration testing according to claim 8, characterized in that, The thermoelectric cooling element and the positive temperature coefficient heating element are alternately arranged on the surface of the metal shielding layer; The cold end of the thermoelectric cooling chip is attached to the metal shielding layer with its cold end facing inward, and the hot end is welded with aluminum heat dissipation fins, which penetrate the aerogel insulation layer.

10. A bus temperature control system for wide-temperature-range catenary servo vibration testing, applied to a multi-servo node cascaded bus topology system for catenary servo vibration testing, characterized in that... include: The segmented constant temperature cable connects two adjacent servo nodes and has a length less than a set value. The outer layer of the segmented constant temperature cable is a metal heat-conducting layer, and the inner layer is a communication cable with a positive temperature coefficient heating element and a thermoelectric cooling element installed. The inner and outer layers are separated by an aerogel heat insulation layer. The temperature acquisition module collects real-time ambient temperature data and communication cable temperature data from the test site. The temperature control decision module dynamically sets the cable temperature control range based on the ambient temperature data; The temperature control execution module drives the positive temperature coefficient heating element and the thermoelectric cooling element to perform temperature adjustment when the temperature data of the communication cable exceeds the temperature control range.

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