Control method and system of inverter compressor for rail train

Abstract

The invention relates to the technical field of control, in particular to a control method and system of an inverter compressor for a rail train. The method comprises the following steps: acquiring temperature data and pressure data in the refrigerated container; based on the temperature data and the pressure data, adopting a preset load demand calculation model to calculate a load demand; and judging whether the load demand is matched with the current compressor frequency, and if not, adjusting the compressor frequency according to the load demand. According to the method, the response speed of temperature control in the refrigerating box can be increased, and the refrigerating effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control, in particular to a control method and system of a variable frequency compressor for a rail train. BACKGROUND

[0002] As a preservation and storage means for inhibiting the growth and reproduction of microorganisms and slowing down the metabolic rate of substances by reducing the ambient temperature, refrigeration technology is widely used in food processing and circulation, pharmaceutical storage, biological sample preservation, chemical raw material storage and other fields. As the core control parameter of refrigeration technology, the control accuracy, stability and response speed of temperature directly determine the quality maintenance effect, storage period and safety of refrigerated goods.

[0003] In the prior art, a refrigeration device mainly uses a traditional fixed-frequency compressor to achieve refrigeration, that is, the temperature inside the refrigeration box is adjusted by controlling the start and stop of the compressor through a temperature controller: when the temperature inside the refrigeration box is higher than the set temperature, the compressor starts refrigeration; when the temperature inside the refrigeration box is lower than the set temperature, the compressor stops working. However, this temperature control method relies on simple temperature thresholds for control and has a relatively lagging response to temperature changes. In actual operation, when the temperature fluctuates greatly, it is difficult to accurately maintain within the set range, for example, under the conditions of frequent start and stop of the train, addition of a large amount of hot food or frequent opening and closing of the refrigerator door by passengers, the temperature inside the refrigeration box will fluctuate greatly. At this time, since the temperature needs to reach a certain threshold before action is taken, the compressor cannot respond in time, thereby causing the temperature to be adjusted in time, and ultimately affecting the refrigeration effect.

[0004] Therefore, how to improve the response speed of temperature control to improve the refrigeration effect is a technical problem that needs to be solved at present. SUMMARY

[0005] To solve the technical problem that the refrigeration effect is poor due to the lagging response of temperature control when the temperature fluctuates greatly, the present application provides a solution in the following aspects.

[0006] In a first aspect, the present application provides a control method of a variable frequency compressor for a rail train, comprising: acquiring temperature data and pressure data inside a refrigeration box; calculating a load demand based on the temperature data and the pressure data using a preset load demand calculation model; determining whether the load demand matches the current frequency of the compressor, and if not, adjusting the frequency of the compressor according to the load demand.

[0007] Further, after acquiring the temperature data and pressure data inside the refrigeration box, the method further comprises: performing weighted averaging on the temperature data collected at the same time to obtain the temperature inside the refrigeration box at that time; and performing filtering processing on the pressure data to obtain smoothed pressure data.

[0008] Furthermore, based on the temperature data and the pressure data, a load demand index is calculated using a preset load demand calculation model, including: determining the temperature deviation based on the current temperature and the target temperature; determining the pressure deviation based on the current pressure and the target pressure; obtaining temperature weights and pressure weights from a preset weight database; and inputting the temperature deviation, the pressure deviation, the temperature weights, and the pressure weights into the load demand calculation model to calculate the current load demand.

[0009] Furthermore, the load demand calculation model is as follows:

[0010] In the formula, This is the load demand index. Temperature weighting, For temperature deviation, For pressure deviation, For pressure deviation, This is a preset temperature deviation mapping function used to convert temperature deviation into its degree of impact on load demand. This is a preset pressure deviation mapping function used to convert pressure deviation into its impact on load demand.

[0011] Furthermore, after obtaining the temperature weight and pressure weight, the method further includes: determining the current working state of the refrigerator based on the current temperature and current pressure; and correcting the pressure weight and temperature weight based on the current working state.

[0012] Furthermore, the operating state includes temperature-sensitive operating state and pressure-sensitive operating state; the current operating state of the refrigerator is determined according to the current temperature and current pressure, including: if the temperature change rate is greater than or equal to a preset temperature change rate threshold, it is determined to be a temperature-sensitive operating state; if the current pressure is greater than or equal to a preset pressure threshold, it is determined to be a pressure-sensitive operating state.

[0013] Furthermore, the pressure weight and the temperature weight are corrected according to the current working state, including: if the current working state is a temperature-sensitive condition, the temperature weight is added to or multiplied by a first correction amount to obtain a corrected temperature weight; the corrected pressure weight is determined according to the corrected temperature weight; the corrected pressure weight and the corrected temperature weight are negatively correlated.

[0014] In a second aspect, the present application provides a variable frequency compressor intelligent control system for a rail train, comprising: a temperature sensor and a pressure sensor; the temperature sensor is used to collect temperature data in the refrigeration box, and the pressure sensor is used to collect pressure data in the refrigeration box; a controller connected with the temperature sensor, the pressure sensor and the compressor, used to realize the control method of the variable frequency compressor for the rail train in the first aspect.

[0015] Further, the system further comprises: a variable frequency driver connected with the controller and the compressor, used to receive the control instruction sent by the controller, and control the frequency of the compressor according to the control instruction.

[0016] Further, the system further comprises: a condenser and an evaporator, the condenser is connected with the compressor and the evaporator.

[0017] The beneficial effects of the present application are: compared with the prior art, the present application can accurately calculate the load demand by monitoring the temperature and pressure in the refrigeration box in real time, and dynamically adjust the frequency of the compressor according to the load demand, so that the refrigerating capacity of the compressor matches the actual demand of the refrigeration box, thereby ensuring the refrigeration effect. This dynamic adjustment method based on real-time data effectively solves the slow response problem of traditional fixed-frequency compressors, improves the control accuracy, reduces the frequent start and stop of the compressor, and prolongs the service life of the compressor and reduces the energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The flow chart of the control method of the variable frequency compressor for the rail train in the embodiment of the present application is shown. Figure 2 The structural block diagram of the variable frequency compressor intelligent control system for the rail train in the embodiment of the present application is shown. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] The specific embodiments of the present application will be described in detail below with reference to the drawings.

[0021] Figure 1 The flow chart of the control method of the variable frequency compressor for the rail train in the embodiment of the present application is shown.

[0022] Refrigeration equipment typically uses fixed-frequency compressors, which can only operate at a fixed power and cannot be adjusted according to actual refrigeration needs. When the temperature inside the refrigerator approaches the set value, the compressor continues to cool, causing the temperature to drop too low. Subsequently, it needs to restart to raise the temperature, resulting in large temperature fluctuations and affecting the refrigeration effect of food, especially temperature-sensitive foods.

[0023] Meanwhile, this frequent starting and stopping causes significant mechanical shock to the compressor, accelerating wear and tear, reducing its lifespan, and increasing maintenance costs. Furthermore, fixed-frequency compressors consume considerable energy during startup and shutdown, and remain in standby mode when cooling is not needed, resulting in energy waste. Given the limited energy supply of rail trains, this energy-intensive cooling method increases the train's operating costs.

[0024] Because the compressor only activates when the temperature reaches a certain threshold, it cannot respond promptly when the temperature inside the refrigerator changes rapidly, such as when a large amount of hot food is put in or when passengers frequently open and close the door. This results in untimely temperature regulation and further affects the refrigeration effect.

[0025] To address one or more of the aforementioned technical problems, in a first aspect, the present invention provides a control method for a variable frequency compressor for rail trains. Specifically, as shown... Figure 1 As shown, the method of the present invention includes the following steps.

[0026] S1. Obtain temperature and pressure data inside the refrigerator.

[0027] Specifically, temperature data inside the refrigerator is collected by a temperature sensor, and pressure data inside the refrigerator, i.e., pressure changes within the refrigeration system, is collected by a pressure sensor.

[0028] It should be noted that the temperature sensor used must be able to accurately measure the temperature at various locations inside the refrigerator. That is, the temperature sensor integrates multiple temperature measurement units, each of which collects the temperature at a specific location within the refrigerator. Alternatively, the temperature sensor is a temperature sensor array with multiple temperature sensors (i.e., temperature measurement units).

[0029] In one embodiment, after acquiring the temperature and pressure data inside the refrigerator, the method of the present invention further includes: performing a weighted average of the temperature data collected at the same time to obtain an average temperature, that is, using the average temperature as the temperature inside the refrigerator at that time. Specifically, the calculation expression for the average temperature is:

[0030] In the formula, The average temperature. For the first The weight of each temperature measurement unit, For the first The temperature measured by each temperature measurement unit This represents the number of temperature measurement units.

[0031] In one embodiment, the weight of the temperature measurement unit can be set by experts based on the degree of influence of the temperature measurement unit's location on the refrigeration effect.

[0032] By determining the weight of temperature measurement units based on their impact on refrigeration performance, the accuracy of temperature measurement within the refrigeration unit can be improved, thereby enhancing the accuracy of subsequent load determination.

[0033] Furthermore, the pressure data is filtered to obtain balanced pressure data. Filtering the pressure data eliminates high-frequency interference, thereby improving the accuracy of subsequent load demand calculations.

[0034] S2. Based on temperature and pressure data, calculate the load demand using a preset load demand calculation model.

[0035] In one embodiment, determining load requirements specifically includes the following steps.

[0036] S21. Determine the temperature deviation and pressure deviation.

[0037] Specifically, the temperature deviation is determined based on the current temperature and the target temperature. Specifically, the temperature deviation is obtained by subtracting the target temperature from the current temperature; similarly, the pressure deviation is obtained by subtracting the target pressure from the current pressure. The target temperature and target pressure are set manually.

[0038] If the temperature is higher than the target temperature and the pressure is lower, it indicates that the cooling capacity needs to be increased, which means the compressor frequency can be increased; conversely, if the temperature is close to the target temperature and the pressure is normal, it indicates that the load demand is low, which means the compressor frequency can be reduced.

[0039] By determining the actual load demand of the refrigerated container based on the temperature and pressure inside, and then dynamically adjusting the compressor frequency according to the load demand, the idling and over-cooling of traditional fixed-frequency compressors when refrigeration is not needed are avoided, which effectively reduces energy consumption, meets the requirements of energy conservation and emission reduction for rail trains, and reduces operating costs.

[0040] S22, Obtain temperature weight and pressure weight.

[0041] In this embodiment, the temperature weight and pressure weight can be set by experts or obtained by matching from a preset weight database. The sum of the temperature weight and pressure weight is 1.

[0042] In one embodiment, after obtaining the temperature weight and pressure weight, the method of the present invention further includes: determining the current operating state of the refrigerator based on the current temperature and current pressure; and correcting the pressure weight and temperature weight based on the current operating state. The operating state includes temperature-sensitive operating conditions, pressure-sensitive operating conditions, and normal operating conditions.

[0043] Specifically, if the rate of temperature change is greater than or equal to a preset temperature change rate threshold, it indicates that the temperature fluctuation is relatively large, possibly caused by frequent opening and closing of the refrigerator or the placement of hot food, thus determining the current operating state as a temperature-sensitive condition. The temperature change rate threshold is set manually. In an optional embodiment, the temperature change rate threshold can be determined based on the temperature change rate under different scenarios. Specifically, the temperature change rate when the refrigerator door is opened and closed, and the temperature change rate when hot food is placed inside, are calculated, and the average of these two values ​​is used to obtain the temperature change rate threshold.

[0044] If the current pressure is greater than or equal to a preset pressure threshold, the current operating state is determined to be a pressure-sensitive condition. The pressure threshold is close to a preset safe pressure upper limit; for example, the pressure threshold can be set to 0.9 times the safe pressure upper limit, which is set manually.

[0045] If the rate of temperature change is less than the temperature change rate threshold and the current pressure is less than the pressure threshold, then the current working condition is determined to be normal.

[0046] Furthermore, if the current operating condition is temperature-sensitive, the current temperature weight is added to or multiplied by the first correction amount to obtain the corrected temperature weight; then, 1 is subtracted from the corrected temperature weight to obtain the corrected pressure weight. Wherein, if added, the value range of the first correction amount can be set to 0~0.3; if multiplied, the value range of the first correction amount can be set to 0.8~1.0.

[0047] Similarly, if the current operating condition is a pressure-sensitive condition, the current pressure weight is added to or multiplied by the second correction increment to obtain the corrected pressure weight; then, 1 is subtracted from the corrected pressure weight to obtain the corrected temperature weight. If the weight is added, the second correction increment can range from 0 to 0.3; if the weight is multiplied, the second correction increment can range from 0.8 to 1.0.

[0048] If the current working condition is normal, then the current pressure weight and temperature weight remain unchanged.

[0049] By adjusting the pressure and temperature weights according to different operating conditions, the compressor's operating status can be adjusted in a timely manner, thereby ensuring the response speed and accuracy of temperature control. For example, when frequent opening and closing of the refrigerator door causes drastic temperature fluctuations, increasing the temperature weight allows for a priority response to temperature changes, enabling the temperature inside the refrigerator to quickly return to the target temperature and ensuring the stability of the refrigeration effect; when the pressure inside the refrigerator approaches the pressure threshold, increasing the pressure weight prevents overpressure operation.

[0050] By optimizing the compressor's operating status, frequent starts and stops can be avoided, reducing mechanical shock and extending the compressor's service life. This, in turn, reduces the frequency of equipment maintenance and repair costs, and improves the reliability of train operation.

[0051] S23. Input the temperature deviation, pressure deviation, temperature weight, and pressure weight into the load demand calculation model to calculate the current load demand.

[0052] In this embodiment, the load demand calculation model is as follows:

[0053] In the formula, This is the load demand index. Temperature weighting, For temperature deviation, For pressure deviation, For pressure deviation, This is a preset temperature deviation mapping function used to convert temperature deviation into its degree of impact on load demand. This is a preset pressure deviation mapping function used to convert pressure deviation into its impact on load demand.

[0054] In one embodiment, the temperature deviation mapping function and the pressure deviation mapping function can be piecewise linear functions or nonlinear functions, such as exponential functions, to highlight the significant impact of large deviations on load demand. After determining the type of the temperature deviation mapping function, the temperature deviation is used as the independent variable, and the degree of influence of the temperature deviation on load demand is used as the dependent variable. Then, the unknown parameters in the temperature deviation mapping function are determined using the least squares method, ultimately yielding the temperature deviation mapping function. The degree of influence of the temperature deviation on load demand is determined by experts. Similarly, the method for determining the pressure deviation mapping function is similar to that for the temperature deviation mapping function, and will not be elaborated here.

[0055] This load demand calculation model can accurately calculate the actual load demand of the compressor, thereby improving the accuracy of subsequent compressor frequency adjustments.

[0056] S3. Adjust the compressor frequency according to load requirements.

[0057] Specifically, it determines whether the load demand matches the current compressor frequency. If so, the current compressor frequency is maintained; otherwise, the compressor frequency is adjusted according to the calculated load demand. More specifically, based on a preset load demand-target frequency mapping relationship, the load demand is converted into a target frequency suitable for the compressor, and then this target frequency is sent to the inverter driver, so that the compressor frequency matches the load demand, ultimately achieving dynamic adaptation of cooling capacity.

[0058] In one embodiment, a preset fuzzy PID control optimization algorithm can be used to control the temperature inside the refrigerator.

[0059] Specifically, the temperature deviation and the rate of change of temperature deviation are calculated. The temperature deviation is obtained by subtracting the target temperature from the current temperature; the rate of change of temperature deviation is obtained by dividing the temperature deviation by time.

[0060] The temperature deviation and its rate of change are input into the fuzzy PID control optimization algorithm to calculate the PID parameter adjustment. In this embodiment, the PID parameter adjustment includes the proportional coefficient adjustment, the derivative coefficient adjustment, and the integral coefficient adjustment.

[0061] Furthermore, the temperature deviation and the rate of change of temperature deviation are fuzzified. Specifically, a triangular membership function is used to map the input temperature deviation and the rate of change of temperature deviation to a fuzzy set, which includes negative large, negative medium, negative small, zero, positive small, positive medium, and positive large.

[0062] Furthermore, fuzzy inference is performed based on preset module rules to obtain fuzzy output quantities; the centroid method is used to defuzzify the fuzzy output quantities to obtain precise PID parameter adjustment quantities. The Mamdani inference method (min-max inference) can be used for fuzzy inference, and other inference methods can be used by those skilled in the art; no restrictions are imposed here.

[0063] The preset fuzzy rules include: if the temperature deviation is large and the rate of change of the temperature deviation is large, it indicates that the current temperature deviates far from the target temperature and changes rapidly, so the proportional coefficient is increased, that is, the adjustment amount of the proportional coefficient is greater than 0, in order to quickly reduce the deviation; if the temperature deviation is small and the rate of change of the temperature deviation is small, it indicates that the temperature is close to the target temperature and changes slowly with small fluctuations, so the integral coefficient is increased, that is, the adjustment amount of the integral coefficient is greater than 0, in order to eliminate steady-state error; if the temperature deviation is small and the rate of change of the temperature deviation is large, it indicates that the current temperature fluctuates greatly, so the derivative coefficient is increased, that is, the adjustment amount of the derivative coefficient is greater than 0, in order to suppress temperature fluctuations, ensure stable temperature control, and thus ensure the refrigeration effect.

[0064] Traditional PID controllers have fixed parameters, making it difficult to adapt to complex operating conditions such as train vibration and start-stop cycles. To address this, this invention uses fuzzy logic to dynamically adjust the PID parameters, thereby determining the accuracy and response speed of temperature control. For example, when hot food is placed inside, the temperature deviation can be large and change rapidly. In this case, by increasing the proportional coefficient / proportional term, the system can quickly respond to temperature changes, allowing the temperature inside the refrigerator to rapidly return to the target temperature.

[0065] By monitoring the temperature changes inside the refrigerator in real time and precisely adjusting the frequency of the inverter compressor according to the actual situation, the temperature inside the refrigerator can be stably maintained within the set range, reducing temperature fluctuations and thus improving the refrigeration effect.

[0066] Figure 2 This is a structural block diagram of the intelligent control system for variable frequency compressors for rail trains in an embodiment of the present invention.

[0067] In a second aspect, the present invention provides an intelligent control system for a variable frequency compressor used in rail trains. Specifically, as... Figure 2 As shown, the intelligent control system for a variable frequency compressor of the present invention includes at least a temperature sensor, a pressure sensor, a controller, and a compressor. The temperature sensor is used to collect temperature data of the refrigerator compartment, and the pressure sensor is used to collect pressure data of the refrigerator compartment. The controller (main control chip) is connected to the pressure sensor, the temperature sensor, and the compressor to implement the control method for a variable frequency compressor for rail trains described in the first aspect.

[0068] In addition, the intelligent control system for the variable frequency compressor may also include a variable frequency drive, a condenser, and an evaporator. The variable frequency drive is connected to the controller and the compressor, and the condenser is connected to the compressor and the evaporator. Specifically, the variable frequency drive receives control commands from the controller and controls the compressor frequency accordingly; the condenser dissipates heat from the high-temperature, high-pressure refrigerant; and the evaporator evaporates the refrigerant, absorbing heat from the refrigerator during the evaporation process to achieve a cooling effect.

[0069] The working process of this variable frequency compressor intelligent control system is as follows: the temperature sensor and pressure sensor transmit the real-time collected temperature data and pressure data to the controller, respectively. The controller processes the received temperature data and pressure data, calculates the current load demand, and then determines whether the load demand matches the current compressor frequency. If so, the current compressor frequency is maintained, and temperature data and pressure data are continued to be received; if not, the corresponding control command is sent to the variable frequency drive according to the load demand. After receiving the control command, the variable frequency drive sends the corresponding control signal to the compressor, and the compressor operates at the corresponding frequency according to the control signal.

[0070] During operation, the compressor compresses the refrigerant to obtain a high-temperature, high-pressure refrigerant. This high-temperature, high-pressure refrigerant is then transported to the condenser through corresponding pipes for heat dissipation, resulting in a low-temperature, high-pressure liquid. This liquid then enters the evaporator through corresponding pipes to evaporate, absorbing the pressure inside the refrigerator and achieving the refrigeration effect.

[0071] By adjusting the compressor frequency, the compressor power is regulated, thereby controlling the cooling capacity and ultimately regulating the temperature inside the refrigerator. The coordinated operation of the condenser, evaporator, and compressor ensures the normal operation of the refrigeration system, thus achieving precise temperature control within the refrigerator.

[0072] The intelligent control system of this invention is not only applicable to vertical refrigerators on rail trains, but can also be applied to other refrigeration equipment, such as refrigerators and freezers. Furthermore, this intelligent control system possesses a certain degree of anti-interference capability to ensure stable operation under the rail train's operating environment (electromagnetic interference, vibration). Simultaneously, it also has a fault diagnosis function; when an anomaly / fault is detected, it can promptly issue an alarm and provide fault information, thereby improving the response speed for maintenance.

[0073] In the description of this specification, "multiple" means at least two, such as two, three or more, unless otherwise explicitly specified. Furthermore, the steps described above are for clarity only; in implementation, they can be combined into one step or some steps can be broken down into multiple steps, as long as they include the same logical relationships.

[0074] While this specification has shown and described numerous embodiments of the invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of this invention.

Claims

1. A control method for a variable frequency compressor for rail trains, characterized in that, include: Acquire temperature and pressure data inside the refrigerator; Based on the temperature data and the pressure data, the load demand is calculated using a preset load demand calculation model. Determine whether the load demand matches the compressor's current frequency. If not, adjust the compressor's frequency according to the load demand.

2. The control method for a variable frequency compressor for rail trains according to claim 1, characterized in that, After obtaining the temperature and pressure data inside the refrigerator, the following is also included: The temperature inside the refrigerator at that moment is obtained by weighted averaging of temperature data collected at the same time. The pressure data is filtered to obtain smoothed pressure data.

3. The control method for a variable frequency compressor for railcars according to claim 1 or 2, characterized in that, Based on the temperature data and the pressure data, a load demand index is calculated using a preset load demand calculation model, including: Determine the temperature deviation based on the current temperature and the target temperature; Determine the pressure deviation based on the current pressure and the target pressure; Retrieve temperature and pressure weights from a pre-defined weight database; The temperature deviation, the pressure deviation, the temperature weight, and the pressure weight are input into the load demand calculation model to calculate the current load demand.

4. The control method for a variable frequency compressor for rail trains according to claim 3, characterized in that, The load demand calculation model is as follows: In the formula, To meet load requirements, Temperature weighting, For temperature deviation, For pressure deviation, For pressure deviation, This is a preset temperature deviation mapping function used to convert temperature deviation into its degree of impact on load demand. This is a preset pressure deviation mapping function used to convert pressure deviation into its impact on load demand.

5. The control method for a variable frequency compressor for rail trains according to claim 3, characterized in that, After obtaining the temperature weight and pressure weight, the following is also included: Determine the current operating status of the refrigerator based on the current temperature and pressure; The pressure weight and temperature weight are adjusted according to the current working status.

6. The control method for a variable frequency compressor for rail trains according to claim 5, characterized in that, The operating conditions include temperature-sensitive conditions and pressure-sensitive conditions; Determine the current operating status of the refrigerator based on the current temperature and pressure, including: If the rate of temperature change is greater than or equal to the preset temperature change rate threshold, it is determined to be a temperature-sensitive operating condition. If the current pressure is greater than or equal to the preset pressure threshold, it is determined to be a pressure-sensitive operating condition.

7. The control method for a variable frequency compressor for rail trains according to claim 5, characterized in that, The pressure weight and temperature weight are corrected according to the current working status, including: If the current working state is a temperature-sensitive condition, the temperature weight is added to or multiplied by the first correction amount to obtain the corrected temperature weight. The corrected pressure weight is determined based on the corrected temperature weight; the corrected pressure weight is negatively correlated with the corrected temperature weight.

8. A variable frequency compressor intelligent control system for rail trains, characterized in that, include: Temperature sensor and pressure sensor; the temperature sensor is used to collect temperature data inside the refrigerator, and the pressure sensor is used to collect pressure data inside the refrigerator. A controller, connected to the temperature sensor, the pressure sensor, and the compressor, is used to implement the control method for a variable frequency compressor for rail trains as described in any one of claims 1 to 7.

9. The intelligent control system for variable frequency compressors for rail trains according to claim 8, characterized in that, Also includes: A variable frequency drive, connected to the controller and the compressor, is used to receive control commands sent by the controller and control the frequency of the compressor according to the control commands.

10. The intelligent control system for variable frequency compressors for rail trains according to claim 8 or 9, characterized in that, Also includes: A condenser and an evaporator, wherein the condenser is connected to the compressor and the evaporator.

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