Air conditioning hot gas bypass control method, device, medium and equipment for rail vehicles

Abstract

The air conditioning hot gas bypass control method, device, medium and equipment for rail vehicles provided by the present invention are applied to the field of vehicle air conditioning control technology. The method comprises: first, obtaining the current inside and outside temperature of the rail vehicle and the operating pressure parameters of the air conditioning refrigeration system, and calculating the working parameters of the compressor, heat exchanger and thermal expansion valve. Secondly, based on the error between the return air temperature in the vehicle and the target temperature, the current cooling demand is calculated and a corresponding PWM control signal is generated. Finally, the opening of the hot gas bypass valve is adjusted using the PWM control signal, thereby adjusting the refrigerant flow rate so that the temperature in the vehicle reaches the target value. The present invention calculates the cooling demand by comprehensive temperature and pressure parameters, and uses PWM control to achieve precise control of the hot gas bypass valve, so that the hot gas bypass control of the rail vehicle can adapt to the load changes inside and outside the vehicle, thereby improving the energy-saving effect of the hot gas bypass.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle air-conditioning control, and in particular to a method, device, medium and equipment for controlling air-conditioning hot air bypass of a rail vehicle. Background Art

[0002] Hot gas bypass is a train air conditioning energy efficiency adjustment technology that mainly improves efficiency under partial load conditions by adjusting the hot gas flow from the compressor exhaust to the evaporator. The hot gas bypass valve can maintain a stable evaporation pressure and effectively adjust the cooling capacity, thereby avoiding frequent start and stop of the compressor, thereby achieving energy saving.

[0003] The main control method of existing hot gas bypass is constant flow control, that is, by setting a fixed evaporation pressure threshold, the constant opening is maintained to maintain a constant bypass hot gas flow. However, although the control method of constant flow control is simple to implement, the adjustment is rough and it is difficult to adapt to the dynamic changes of load, resulting in large fluctuations in temperature and humidity, and the energy saving effect is not obvious.

[0004] Therefore, how to effectively control the hot gas bypass of rail vehicles under dynamic load changes and improve energy-saving effects has become a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of the above problems, the present invention provides a method, device, medium and equipment for controlling hot air bypass of an air conditioner in a rail vehicle that overcomes the above problems or at least partially solves the above problems. The technical solution is as follows:

[0006] A method for controlling hot air bypass of an air conditioner in a rail vehicle, comprising:

[0007] Obtaining target operating state parameters of the rail vehicle at the current moment, wherein the target operating state parameters include indoor and outdoor temperature parameters of the rail vehicle and operating pressure parameters of an air-conditioning and refrigeration system, and the operating pressure parameters of the air-conditioning and refrigeration system are related to the refrigerant flow rate of a hot gas bypass valve in the air-conditioning and refrigeration system of the rail vehicle;

[0008] Obtaining compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air conditioning and refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air conditioning and refrigeration system operating pressure parameters;

[0009] Based on the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature, the target cooling demand calculation result of the rail vehicle at the current moment is obtained by using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters;

[0010] Obtaining a PWM control signal that matches the target cooling demand calculation result;

[0011] The PWM control signal is used to control the opening of the hot gas bypass valve of the rail vehicle to adjust the refrigerant flow rate flowing through the hot gas bypass valve at a next moment, so that the return air temperature in the vehicle at the next moment is adjusted to the preset target temperature.

[0012] Optionally, obtaining a PWM control signal that matches the target cooling demand calculation result includes:

[0013] When the target cooling demand calculation result is within a first preset percentage interval, a low cooling demand PWM control signal is generated, wherein the low cooling demand PWM control signal is used to control the air conditioning refrigeration system to start a compressor and open one of the hot gas bypass valves;

[0014] When the target cooling demand calculation result is within the second preset percentage interval, a medium cooling demand PWM control signal is generated, wherein the medium cooling demand PWM control signal is used to control the air conditioning refrigeration system to start two compressors and open two hot gas bypass valves;

[0015] When the target cooling demand calculation result is within the third preset percentage interval, a high cooling demand PWM control signal is generated, wherein the high cooling demand PWM control signal is used to control the air conditioning refrigeration system to start two compressors and close one of the hot gas bypass valves;

[0016] When the target cooling demand calculation result is within a fourth preset percentage interval, a maximum cooling demand PWM control signal is generated, wherein the maximum cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and close all the hot gas bypass valves.

[0017] Optionally, the first preset percentage interval is 4% to 25%, the second preset percentage interval is 26% to 50%, the third preset percentage interval is 51% to 75%, and the fourth preset percentage interval is 75% to 100%.

[0018] Optionally, the vehicle interior and exterior temperature parameters include the exterior ambient temperature of the rail vehicle, the interior return air temperature and the interior supply air temperature, and the air-conditioning and refrigeration system operating pressure parameters include the condensing pressure and the evaporating pressure of the air-conditioning and refrigeration system.

[0019] Optionally, after obtaining the target operating state parameters of the rail vehicle at the current moment, the method further includes:

[0020] When the ambient temperature outside the vehicle is lower than a first preset temperature threshold, the air conditioning and refrigeration system is stopped, and the fresh air damper of the rail vehicle is opened to maintain the return air temperature inside the vehicle at a preset target temperature;

[0021] When the ambient temperature outside the vehicle is greater than a second preset temperature threshold, the air conditioning and refrigeration system is started, and the step of obtaining the target operating state parameters of the rail vehicle at the current moment is re-executed.

[0022] Optionally, obtaining the compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air-conditioning and refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air-conditioning and refrigeration system operating pressure parameters includes:

[0023] Inputting the vehicle indoor and outdoor temperature parameters and the air conditioning refrigeration system operating pressure parameters into a pre-built compressor model, and obtaining the compressor operating parameters of the air conditioning refrigeration system output by the compressor model, wherein the compressor operating parameters include the exhaust pressure and the discharge refrigerant flow rate of the compressor in the air conditioning refrigeration system;

[0024] Input the vehicle indoor and outdoor temperature parameters and the air conditioning refrigeration system operating pressure parameters into a pre-built heat exchanger model to obtain the heat exchanger operating parameters of the air conditioning refrigeration system output by the heat exchanger model, wherein the heat exchanger operating parameters include the outlet temperature and heat exchange capacity of the heat exchanger in the air conditioning refrigeration system;

[0025] The vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters are input into a pre-built thermal expansion valve model to obtain the thermal expansion valve operating parameters of the air-conditioning refrigeration system output by the thermal expansion valve model, wherein the thermal expansion valve operating parameters include the valve opening of the thermal expansion valve in the air-conditioning refrigeration system.

[0026] Optionally, the obtaining of the target cooling demand calculation result of the rail vehicle at the current moment based on the temperature error between the return air temperature in the rail vehicle at the current moment and a preset target temperature and using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters includes:

[0027] Using the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature, a calculation result of the initial cooling demand of the rail vehicle at the current moment is obtained;

[0028] Calculate the cooling demand influencing parameters using the exhaust pressure and exhaust refrigerant flow of the compressor, the outlet temperature and heat exchange capacity of the heat exchanger, and the valve opening of the thermal expansion valve;

[0029] The initial cooling requirement calculation result is corrected using the cooling requirement influencing parameter to obtain a target cooling requirement calculation result of the rail vehicle at the current moment.

[0030] An air conditioning hot gas bypass control device for a rail vehicle comprises: a target operating state parameter obtaining unit, a refrigeration component working parameter obtaining unit, a target cooling demand calculation result obtaining unit, a PWM control signal obtaining unit and a hot gas bypass valve control unit.

[0031] The target operating state parameter obtaining unit is used to obtain the target operating state parameter of the rail vehicle at the current moment, wherein the target operating state parameter includes the indoor and outdoor temperature parameters of the rail vehicle and the operating pressure parameter of the air-conditioning and refrigeration system, and the operating pressure parameter of the air-conditioning and refrigeration system is related to the refrigerant flow rate of the hot gas bypass valve in the air-conditioning and refrigeration system of the rail vehicle;

[0032] The refrigeration component working parameter obtaining unit is used to obtain the compressor working parameters, heat exchanger working parameters and thermal expansion valve working parameters of the air-conditioning refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters;

[0033] The target cooling demand calculation result obtaining unit is used to obtain the target cooling demand calculation result of the rail vehicle at the current moment based on the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature, using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters;

[0034] The PWM control signal obtaining unit is used to obtain a PWM control signal that matches the target cooling demand calculation result;

[0035] The hot gas bypass valve control unit is used to control the opening of the hot gas bypass valve of the rail vehicle using the PWM control signal to adjust the refrigerant flow passing through the hot gas bypass valve at the next moment, so that the return air temperature in the vehicle at the next moment is adjusted to the preset target temperature.

[0036] A computer-readable storage medium stores a program, wherein when the program is executed by a processor, the method for controlling hot air bypass of an air conditioner in a rail vehicle described in any one of the above is implemented.

[0037] An electronic device, comprising at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other via the bus; and the processor is used to call program instructions in the memory to execute any one of the above-mentioned air conditioning hot air bypass control methods for rail vehicles.

[0038] By means of the above technical scheme, the present invention provides a method, device, medium and equipment for controlling hot gas bypass of an air conditioner of a rail vehicle, the method comprising: obtaining target operating state parameters of the rail vehicle at the current moment, wherein the target operating state parameters include the indoor and outdoor temperature parameters of the rail vehicle and the operating pressure parameters of the air conditioning refrigeration system, and the operating pressure parameters of the air conditioning refrigeration system are related to the refrigerant flow rate of the hot gas bypass valve in the air conditioning refrigeration system of the rail vehicle; obtaining the compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air conditioning refrigeration system at the current moment by using the indoor and outdoor temperature parameters and the operating pressure parameters of the air conditioning refrigeration system; obtaining the target cooling demand calculation result of the rail vehicle at the current moment by using the compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters based on the temperature error between the indoor return air temperature of the rail vehicle at the current moment and the preset target temperature; obtaining a PWM control signal matching the target cooling demand calculation result; and controlling the opening of the hot gas bypass valve of the rail vehicle by using the PWM control signal to adjust the refrigerant flow rate flowing through the hot gas bypass valve at the next moment, so that the indoor return air temperature at the next moment is adjusted to the preset target temperature. The present invention calculates the cooling demand of the rail vehicle by combining the temperature parameters inside and outside the vehicle and the operating pressure parameters of the air-conditioning refrigeration system, and uses a PWM control signal to adjust the refrigerant flow through the hot gas bypass valve, so that the hot gas bypass control of the rail vehicle can adapt to the load changes inside and outside the vehicle, thereby improving the energy-saving effect of the hot gas bypass.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0041] Figure 1 A schematic diagram of the structure of an air-conditioning and refrigeration system provided by an embodiment of the present invention is shown;

[0042] Figure 2 A schematic diagram illustrating a hot gas bypass structure provided by an embodiment of the present invention is shown;

[0043] Figure 3 A control logic block diagram of an air conditioning hot gas bypass control method provided by an embodiment of the present invention is shown;

[0044] Figure 4 A schematic flow chart showing an implementation of a method for controlling hot air bypass of an air conditioner in a rail vehicle provided in an embodiment of the present invention;

[0045] Figure 5 A dynamic cycle control block diagram of an air conditioning hot gas bypass control method for a rail vehicle provided by an embodiment of the present invention is shown;

[0046] Figure 6 A schematic diagram illustrating polynomial calculation of a compressor model provided by an embodiment of the present invention is shown;

[0047] Figure 7 A schematic diagram showing the principle of the calculation logic of the PID controller provided by an embodiment of the present invention is shown;

[0048] Figure 8 A schematic structural diagram of an air conditioning hot gas bypass control device for a rail vehicle provided by an embodiment of the present invention is shown;

[0049] Fig. 9 A schematic structural diagram of an electronic device provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0050] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0051] Currently, the annual energy consumption of the air conditioning system of urban rail transit (URT) trains depends on many factors, including constant factors and variable factors. In particular, the variable parameters are not only time-varying with the changes in the surrounding environment, but also depend on the train's running line and the associated operating mode. In addition, the choice of refrigerant and the performance of the control system (which determines how to respond to different load conditions) also have an important impact on energy consumption.

[0052] Constant influencing parameters are mainly train characteristics, such as thermal conductivity of the car body and solar radiation factor of the windows. These parameters are relatively stable throughout the operation. Variable influencing parameters can include weather characteristics (environmental conditions such as temperature and humidity vary with seasons and time periods), passenger capacity (fluctuations in the number of passengers, including morning and evening peaks, weekdays and holidays), train operating conditions (including the state of the train in tunnels and on the road, and changes in different weather (such as sunny, cloudy, rainy days)) and door opening and closing frequency (determined by the frequency of passenger transfers and train stops within the station).

[0053] These factors not only involve passenger comfort requirements and the number of passengers, but also affect the selection of the main components of the air conditioning unit, thereby determining the energy consumption of the system.

[0054] like Figure 1 As shown in the figure, the main components of the HVAC system (Heating Ventilation and Air Conditioning, HVAC) of rail vehicles, which consists of air conditioning units, include compressors, ventilators, condensing fans (only running in cooling mode) and heating components. Therefore, energy regulation of these main components has become one of the important means to achieve energy saving.

[0055] like Figure 2 As shown in the figure, hot gas bypass (HGPB) is an energy efficiency regulation technology in the air conditioning and refrigeration system of rail vehicles. It mainly improves the operating efficiency of the air conditioning unit under partial load conditions by changing the hot gas flow rate from the compressor exhaust directly into the evaporator. The current hot gas bypass valve is an economical method to control the cooling capacity of the compressor and can be used instead of unloading the compressor cylinder. The hot gas bypass valve can automatically bypass the required high-temperature and high-pressure gas of the compressor to the low-pressure side to maintain the stability of the evaporation pressure. The thermal bypass valve will sense the downstream pressure changes and open when the evaporation pressure drops below the valve setting value. By changing the evaporator liquid supply, energy regulation is achieved. When the load is large and the evaporation pressure is higher than the valve setting value, the thermal bypass valve remains closed and the air conditioning and refrigeration system operates normally.

[0056] After the hot gas bypass is enabled, part of the high-temperature and high-pressure steam discharged from the compressor does not pass through the condenser, but directly enters the inlet of the evaporator through the bypass pipe, and mixes with the low-pressure and low-temperature refrigerant in the evaporator to increase the evaporation pressure and temperature. Due to the increase in evaporation temperature, the ability of the evaporator to absorb heat decreases, the amount of cold supplied to the cold load decreases, and the effective cooling capacity of the unit decreases; at the same time, the high-temperature steam also brings some heat after entering, further offsetting the cooling effect of the evaporator. Therefore, by adjusting the flow rate of the bypass hot gas, the amount of cold supplied to the room by the unit can be continuously adjusted to achieve the adjustment of the cooling capacity, and the compressor does not need to be frequently started and stopped at partial load. The larger the bypass hot gas flow rate, the more the effective cooling capacity decreases, which plays a role in energy regulation, thereby achieving the purpose of energy saving.

[0057] At present, constant flow control is the main method of hot gas bypass control. By setting a fixed evaporation pressure threshold, the opening is constant to maintain a constant bypass hot gas flow. This method is simple to implement, but the adjustment is rough. The operating conditions of rail vehicles are relatively complex. The air conditioning and refrigeration system of rail vehicles has been working under conditions of large changes in heat load and rapid changes in temperature and humidity for a long time. The method of using constant flow control to bypass hot gas is difficult to adapt to the dynamic changes in load, which easily leads to large fluctuations in temperature and humidity, making the energy saving effect not obvious. Therefore, the complexity of the operating conditions of urban rail vehicles has put forward higher requirements for the energy efficiency adjustment of the air conditioning and refrigeration system.

[0058] Based on this, in an embodiment of the present invention, a method for controlling hot air bypass of an air conditioner in a rail vehicle is provided. Figure 3 The figure shows a control logic block diagram of the air conditioning hot gas bypass control method, which includes: first, obtaining the current inside and outside temperature of the rail vehicle and the operating pressure parameters of the air conditioning refrigeration system, and calculating the working parameters of the compressor, heat exchanger and thermal expansion valve. Secondly, based on the error between the return air temperature in the vehicle and the target temperature, the current cooling demand is calculated and a corresponding PWM control signal is generated. Finally, the opening of the hot gas bypass valve is adjusted using the PWM control signal, thereby adjusting the refrigerant flow rate so that the temperature in the vehicle reaches the target value. It can be seen that the present invention uses the PWM control method to achieve precise control of the hot gas bypass valve by calculating the cooling demand through comprehensive temperature and pressure parameters, so that the hot gas bypass control of the rail vehicle can adapt to the load changes inside and outside the vehicle, and improve the energy-saving effect of the hot gas bypass.

[0059] like Figure 4 As shown, a flow chart of an implementation of a method for controlling hot air bypass of an air conditioner in a rail vehicle provided by an embodiment of the present invention is provided. The method may include:

[0060] S100. Obtain target operating state parameters of the rail vehicle at the current moment, wherein the target operating state parameters include indoor and outdoor temperature parameters of the rail vehicle and operating pressure parameters of the air-conditioning and refrigeration system, and the operating pressure parameters of the air-conditioning and refrigeration system are related to the refrigerant flow rate of the hot gas bypass valve in the air-conditioning and refrigeration system of the rail vehicle.

[0061] Among them, the in-vehicle and out-vehicle temperature parameters mainly include in-vehicle temperature parameters and out-vehicle temperature parameters.

[0062] The in-car temperature parameter refers to the air temperature inside the carriage of a rail vehicle, which is usually measured by a temperature sensor deployed by the Train Control and Management System (TCMS). In the air conditioning and refrigeration system, the in-car temperature is an important indicator for determining the cooling demand to ensure the comfort of passengers. The in-car temperature parameters can specifically include the in-car return air temperature and the in-car supply air temperature.

[0063] The return air temperature refers to the temperature of the air inside the train compartment when it is sucked back into the air conditioning and refrigeration system for recirculation. Measured by the internal temperature sensor, this temperature reflects the actual temperature inside the compartment and is one of the main bases for the air conditioning system to adjust.

[0064] The in-car air supply temperature refers to the temperature of the air conditioning and refrigeration system of a rail vehicle when it returns the processed cold air to the interior of the vehicle. The supply air temperature affects the comfort of passengers and is used to adjust the system output to meet the preset in-car temperature.

[0065] The outside temperature parameter refers to the ambient temperature outside the rail vehicle compartment, also known as the outside ambient temperature parameter, which is also measured by a temperature sensor. The outside temperature affects the ease of temperature regulation and the cooling load inside the vehicle. For example, in hot external environments, the cooling demand increases.

[0066] The air conditioning and refrigeration system operating pressure parameter refers to the working pressure in the air conditioning and refrigeration system of the rail vehicle, which is generally measured by a differential pressure sensor. The air conditioning and refrigeration system operating pressure parameter includes the pressure of the condenser on the high-pressure side and the evaporator on the low-pressure side of the air conditioning and refrigeration system, that is, the condensing pressure and evaporating pressure of the air conditioning and refrigeration system.

[0067] The condensing pressure is the pressure of the refrigerant at the condenser. The condenser is the part of the refrigeration system where the refrigerant condenses from gas to liquid, releasing heat to the outside. The condensing pressure affects the condensation efficiency of the refrigerant and the overall performance of the system.

[0068] The evaporation pressure is the pressure of the refrigerant at the evaporator. The evaporator is another part of the refrigeration system where the refrigerant evaporates from liquid to gas, absorbing heat from the interior of the vehicle. The evaporation pressure determines the evaporation temperature of the refrigerant and the cooling effect.

[0069] It is understood that when the refrigerant flows in the system, it passes through various components such as the compressor, condenser, evaporator and expansion valve. The hot gas bypass valve is used to adjust part of the refrigerant flow so that it bypasses the evaporator and directly enters the low-pressure side to control the pressure and temperature of the evaporator. By adjusting the bypass valve, the air conditioning refrigeration system can more accurately control the cooling capacity, adapt to different load conditions, avoid frequent startup of the compressor, and improve the energy efficiency and stability of the air conditioning refrigeration system.

[0070] S110, obtaining compressor operating parameters, heat exchanger operating parameters, and thermal expansion valve operating parameters of the air-conditioning refrigeration system under the influence of vehicle indoor and outdoor temperature parameters and air-conditioning refrigeration system operating pressure parameters.

[0071] Among them, the compressor operating parameters refer to the key indicators that describe the operating status and performance of the compressor in the air conditioning and refrigeration system. In the air conditioning and refrigeration system provided by the embodiment of the present invention, the ambient temperature outside the vehicle directly affects the heat dissipation capacity of the condenser. When the temperature outside the vehicle is high, the heat dissipation effect of the condenser decreases, resulting in an increase in the condensation pressure, and the high condensation pressure requires the compressor to require more energy to compress the refrigerant, increasing the workload of the compressor. The return air temperature in the vehicle and the supply air temperature in the vehicle are direct manifestations of the heat load of the vehicle environment. High return air temperature or supply air temperature means that the heat load in the vehicle is large. When the heat load in the vehicle increases, the air conditioning and refrigeration system needs to increase the output capacity of the compressor to meet the cooling demand, which will lead to the adjustment of the compressor operating parameters, such as increasing the exhaust pressure and the refrigerant flow rate. At the same time, the temperature parameters inside and outside the vehicle not only affect the compressor, but are also closely related to the evaporation pressure and the condensation pressure. High temperature inside the vehicle will lead to high evaporation pressure, which in turn requires the compressor to increase the compression ratio; high temperature outside the vehicle will lead to high condensation pressure, increasing the load of the compressor. Therefore, the embodiment of the present invention collects the compressor operating parameters of the air conditioning and refrigeration system under the influence of the temperature parameters inside and outside the vehicle and the operating pressure parameters of the air conditioning and refrigeration system, so as to subsequently calculate the accurate cooling demand.

[0072] Among them, the heat exchanger operating parameters refer to the key indicators that describe the operating status and performance of the condenser and evaporator in the air conditioning and refrigeration system. In the air conditioning and refrigeration system provided by the embodiment of the present invention, the ambient temperature outside the vehicle directly affects the heat exchange effect between the condenser and the external environment. When the ambient temperature is high, the heat dissipation difficulty of the condenser increases, thereby affecting the condensation effect and the condensation pressure. The return air temperature in the car determines the initial temperature of the air entering the evaporator. The supply air temperature in the car reflects the heat exchange effect of the evaporator. The return air temperature in the car and the supply air temperature in the car jointly affect the heat exchange amount and the state of the refrigerant of the evaporator, and determine the overall performance of the evaporator. At the same time, the condensation pressure and the evaporation pressure directly reflect the state of the refrigerant in the condenser and the evaporator, and also affect the temperature and flow of the refrigerant, thereby affecting the heat exchange performance of the heat exchanger. For example: high condensation pressure may cause the refrigerant temperature at the condenser outlet to rise, affecting the subsequent heat exchange process. Therefore, the embodiment of the present invention collects the heat exchanger operating parameters of the air conditioning and refrigeration system under the influence of the temperature parameters inside and outside the car and the operating pressure parameters of the air conditioning and refrigeration system, so as to subsequently calculate the accurate cooling demand.

[0073] Among them, the working parameters of the thermal expansion valve refer to the key indicators that describe the operating status and performance of the thermal expansion valve in the air-conditioning and refrigeration system. In the air-conditioning and refrigeration system provided by the embodiment of the present invention, the ambient temperature outside the vehicle changes the heat dissipation effect of the condenser, thereby affecting the condensation pressure. The fluctuation of the condensation pressure will change the pressure distribution of the entire refrigeration system, thereby affecting the working pressure and temperature of the evaporator. The return air temperature in the car and the supply air temperature in the car represent the heat load in the car. The change in heat load will cause the load of the evaporator to change, affecting the refrigerant temperature at the outlet of the evaporator, that is, the temperature of the temperature sensing package. The temperature of the temperature sensing package is one of the important input parameters of the thermal expansion valve. At the same time, the evaporation pressure and the condensation pressure directly affect the working state of the evaporator and the condenser. These pressure changes will further affect the control and regulation of the thermal expansion valve. Therefore, the embodiment of the present invention collects the working parameters of the thermal expansion valve of the air-conditioning and refrigeration system under the influence of the temperature parameters inside and outside the car and the operating pressure parameters of the air-conditioning and refrigeration system, so as to subsequently calculate the accurate cooling demand.

[0074] S120. Based on the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature, the target cooling demand calculation result of the rail vehicle at the current moment is obtained by using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters.

[0075] The temperature error between the return air temperature in the car and the preset target temperature is the basis for calculating the cooling demand. The operating parameters of the compressor, heat exchanger and thermal expansion valve will affect the actual cooling demand. The adjustment of the compressor parameters directly affects the circulation volume and cooling effect of the refrigerant. The adjustment of the heat exchanger parameters affects the temperature change and heat exchange efficiency of the refrigerant. The adjustment of the thermal expansion valve directly affects the evaporation pressure and the cooling capacity of the evaporator. Therefore, by comprehensively considering and adjusting the above parameters, the optimal working state that meets the cooling demand of the rail vehicle at the current moment is calculated, that is, the target cooling demand calculation result. This result ensures that the temperature in the car can be quickly adjusted to the target temperature that is comfortable for passengers, thereby achieving efficient and stable temperature control effects.

[0076] It should be noted that if a rail vehicle is equipped with multiple air conditioning and refrigeration systems, the cooling demand calculations need to be performed separately.

[0077] S130, obtaining a PWM control signal that matches the target cooling demand calculation result.

[0078] Among them, the PWM (Pulse Width Modulation) control signal is a signal that controls power output by changing the duty cycle of the pulse signal (that is, the ratio of the signal high level time to the period).

[0079] The embodiment of the present invention can compare the target cooling demand calculation result with the performance curve of the air-conditioning refrigeration system. The performance curve is obtained through experiments or simulations, and reflects the output power of the refrigeration system under different PWM control signals. According to the comparison results, the duty cycle of the PWM control signal is adjusted. When the cooling demand is high, the duty cycle is increased to make the refrigeration system run at a higher power; when the cooling demand is low, the duty cycle is reduced to reduce the cooling power. For example, when the calculated cooling demand is high, the duty cycle of the PWM control signal is increased from 50% to 70% to increase the speed of the refrigeration system compressor and increase the cooling power. As the temperature inside the car gradually decreases, the cooling demand decreases, and the duty cycle of the PWM signal is gradually reduced to achieve the purpose of energy saving and stable control.

[0080] S140, using the PWM control signal to control the opening of the hot gas bypass valve of the rail vehicle to adjust the refrigerant flow rate flowing through the hot gas bypass valve at the next moment, so that the return air temperature in the vehicle at the next moment is adjusted to a preset target temperature.

[0081] Among them, the main function of the hot gas bypass valve is to adjust the cooling capacity of the system and prevent the evaporator from freezing by bypassing the high-temperature and high-pressure refrigerant gas discharged from the compressor to the evaporator or suction line. The hot gas bypass valve is usually installed between the exhaust pipe of the compressor and the evaporator or suction line. When the system load is low or under certain specific conditions (such as defrost mode), the hot gas bypass valve will open and introduce a part of the high-temperature and high-pressure refrigerant gas directly into the evaporator or suction line. This can increase the temperature of the evaporator to prevent it from freezing, reduce the frequent switching of the compressor, and improve the stability and life of the system.

[0082] Pulse width modulation uses a square wave whose pulse width is modulated, and the average value of the waveform varies, a pulse wave f(t) with a period of T, and a low value of y min , the high value is y max , with the duty cycle D (duty, cycle), the average value of this wave is:

[0083]

[0084] The description of the above formula can be transformed into:

[0085]

[0086] It can be seen that the average value of the waveform is directly related to the duty cycle D. Assuming that in a PWM signal with a cycle time of 10 seconds, if the pulse width (high level duration) is 8 seconds, then the low level duration is 2 seconds, and the duty cycle of this PWM signal is calculated to be 80%. In the application, when the hot gas bypass solenoid valve is opened, the duty cycle D of the PWM signal can be automatically adjusted by monitoring the changes in the system pressure value, thereby controlling the opening of the hot gas bypass solenoid valve. Ultimately, through this feedback mechanism, the air conditioning refrigeration system can maintain the return air temperature in the car close to the target temperature and achieve constant temperature control.

[0087] It should be noted that Figure 5 The figure shows a dynamic cycle control block diagram of the air conditioning hot gas bypass control method for rail vehicles provided by an embodiment of the present invention. After the hot gas bypass valve is adjusted, the evaporation pressure and the condensation pressure will change accordingly, and the outdoor ambient temperature, the indoor return air temperature and the indoor supply air temperature are also changing dynamically in real time. Therefore, the air conditioning hot gas bypass control process can be dynamically cycled according to the real-time indoor and outdoor temperature parameters and the air conditioning refrigeration system operating pressure parameters.

[0088] The present invention provides an air conditioning hot gas bypass control method for a rail vehicle, the method comprising: obtaining target operating state parameters of the rail vehicle at a current moment, wherein the target operating state parameters include in-vehicle and out-vehicle temperature parameters of the rail vehicle and operating pressure parameters of an air conditioning refrigeration system, and the operating pressure parameters of the air conditioning refrigeration system are related to the refrigerant flow rate of a hot gas bypass valve in the air conditioning refrigeration system of the rail vehicle; obtaining compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air conditioning refrigeration system at a current moment by using the in-vehicle and out-vehicle temperature parameters and the operating pressure parameters of the air conditioning refrigeration system; obtaining a target cooling demand calculation result of the rail vehicle at a current moment by using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters based on a temperature error between an in-vehicle return air temperature of the rail vehicle at a current moment and a preset target temperature; obtaining a PWM control signal matching the target cooling demand calculation result; and controlling the opening of the hot gas bypass valve of the rail vehicle by using the PWM control signal to adjust the refrigerant flow rate flowing through the hot gas bypass valve at a next moment, so that the in-vehicle return air temperature at a next moment is adjusted to the preset target temperature. The present invention calculates the cooling demand of the rail vehicle by combining the temperature parameters inside and outside the vehicle and the operating pressure parameters of the air-conditioning refrigeration system, and uses a PWM control signal to adjust the refrigerant flow through the hot gas bypass valve, so that the hot gas bypass control of the rail vehicle can adapt to the load changes inside and outside the vehicle, thereby improving the energy-saving effect of the hot gas bypass.

[0089] Optional, in the above Figure 4 On the basis of one or more corresponding embodiments, in another optional embodiment provided by the embodiment of the present invention, obtaining a PWM control signal matching the target cooling demand calculation result may specifically include:

[0090] When the target cooling demand calculation result is within the first preset percentage interval, a low cooling demand PWM control signal is generated, wherein the low cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start a compressor and open a hot gas bypass valve.

[0091] Optionally, the first preset percentage interval is 4% to 25%. The low cooling demand PWM control signal is also used to control the opening of the hot gas bypass valve according to a specific target cooling demand. For example, when the target cooling demand is 10%, the opening of the hot gas bypass valve is controlled to be 10°, and when the target cooling demand is 10%, the opening of the hot gas bypass valve is controlled to be 20°.

[0092] When the target cooling demand calculation result is within the second preset percentage interval, a medium cooling demand PWM control signal is generated, wherein the medium cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and open two hot gas bypass valves.

[0093] Optionally, the second preset percentage interval is 26% to 50%. The medium cooling demand PWM control signal is also used to control the opening of the hot gas bypass valve according to the specific target cooling demand. For example, when the target cooling demand is 30%, the openings of the two hot gas bypass valves are controlled to be 15°, and when the target cooling demand is 50%, the openings of the two hot gas bypass valves are controlled to be 25°.

[0094] When the target cooling demand calculation result is within the third preset percentage interval, a high cooling demand PWM control signal is generated, wherein the high cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and close one hot gas bypass valve.

[0095] Optionally, the third preset percentage interval is 51% to 75%. The high cooling demand PWM control signal is also used to control the opening of the hot gas bypass valve according to a specific target cooling demand. For example, when the target cooling demand is 60%, the opening of the hot gas bypass valve that is still open is controlled to be 60°, and when the target cooling demand is 75%, the opening of the open hot gas bypass valve is controlled to be 75°.

[0096] When the target cooling demand calculation result is within the fourth preset percentage interval, a maximum cooling demand PWM control signal is generated, wherein the maximum cooling demand PWM control signal is used to control the air conditioning refrigeration system to start two compressors and close all hot gas bypass valves.

[0097] Optionally, the fourth preset percentage interval is 75% to 100%.

[0098] The embodiment of the present invention generates corresponding PWM control signals according to different intervals of target cooling demand, so that the air conditioning refrigeration system can accurately match the actual cooling demand, thereby avoiding over-cooling or under-cooling, improving the performance of the system and the comfort of users, and enabling the air conditioning refrigeration system to flexibly respond to various environments and load changes, thereby improving the applicability and stability of the system. At the same time, by intelligently controlling the start and stop and working state of the compressor and the hot gas bypass valve, the frequent start and stop of the compressor can be reduced, excessive wear of the equipment can be avoided, and the service life of the equipment can be extended.

[0099] Optional, in the above Figure 4 On the basis of one or more corresponding embodiments, in another optional embodiment provided by the embodiment of the present invention, after obtaining the target operating state parameters of the rail vehicle at the current moment, the method may further include:

[0100] When the ambient temperature outside the vehicle is lower than a first preset temperature threshold, the air conditioning refrigeration system is stopped and the fresh air damper of the rail vehicle is opened to maintain the return air temperature inside the vehicle at a preset target temperature.

[0101] The first preset temperature threshold may be set according to the climate of the location where the rail transit is running. For example, the first preset temperature threshold may be 15°C.

[0102] Among them, the fresh air damper refers to a device used to control the air circulation inside and outside the carriage in a rail vehicle. It is mainly used to adjust the amount of fresh air (fresh air) introduced to ensure the air quality in the carriage and the comfort of passengers. The fresh air damper can be installed in the air conditioning and refrigeration system of a rail vehicle and controlled electrically or pneumatically. The fresh air damper usually consists of one or more adjustable blades or baffles, which can be opened and closed as needed. The air conditioning and refrigeration system automatically adjusts the opening of the fresh air damper according to sensor feedback or preset parameters.

[0103] When the ambient temperature outside the vehicle is lower than a certain threshold, the embodiment of the present invention stops the operation of the air-conditioning refrigeration system and opens the fresh air damper to use the cold air from the outside to adjust the temperature inside the vehicle. This is particularly suitable for effectively using natural cold sources in winter or cold climate conditions to achieve temperature regulation in the compartment of a rail vehicle, thereby more effectively maintaining the preset target temperature, avoiding waste of resources caused by excessive cooling, and ensuring a comfortable experience for passengers in the compartment.

[0104] When the ambient temperature outside the vehicle is greater than the second preset temperature threshold, the air conditioning and refrigeration system is started, and the step of obtaining the target operating state parameters of the rail vehicle at the current moment is re-executed.

[0105] The second preset temperature threshold is greater than the first preset temperature threshold. The difference between the second preset temperature threshold and the first preset temperature threshold may be 1°C. For example, when the first preset temperature threshold is 15°C, the second preset temperature threshold is 16°C.

[0106] In the embodiment of the present invention, when the ambient temperature outside the vehicle is greater than the second preset temperature threshold, the air-conditioning refrigeration system is restarted to control the temperature inside the vehicle compartment, which can effectively maintain a comfortable temperature inside the vehicle compartment. In conjunction with the first preset temperature threshold, natural cooling sources are used preferentially to avoid unnecessary energy consumption, thereby achieving energy-saving effects.

[0107] Optional, in the above Figure 4 On the basis of one or more corresponding embodiments, in another optional embodiment provided by the embodiment of the present invention, obtaining the compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air-conditioning refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters includes:

[0108] The vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters are input into a pre-built compressor model to obtain the compressor operating parameters of the air-conditioning refrigeration system output by the compressor model, wherein the compressor operating parameters include the exhaust pressure and the discharge refrigerant flow rate of the compressor in the air-conditioning refrigeration system.

[0109] The basic model formula of the compressor model provided by the embodiment of the present invention is as follows:

[0110]

[0111]

[0112] Among them, q m is the compressor outlet mass flow rate; p d is the compressor exhaust pressure; p s is the compressor suction pressure; T s is the compressor suction temperature; P is the compressor power; η is the power correction factor; h out is the compressor outlet enthalpy, h in is the compressor inlet enthalpy.

[0113] The polynomial calculations involved in the compressor model can be found in Figure 6 As shown, Te is the evaporation temperature (℃), and the evaporation pressure corresponds to the saturation temperature; Tc is the condensation temperature (℃) and the condensation pressure corresponds to the saturation temperature.

[0114] The input parameters of the compressor model provided by the embodiment of the present invention also include: compressor speed, suction pressure (close to evaporation pressure) and compressor power, and the output parameters are exhaust pressure and exhaust refrigerant flow rate. Among them, the compressor speed determines the working speed of the compressor and has a direct impact on the compression capacity of the compressor. The suction pressure reflects the state of the refrigerant entering the compressor, which is usually close to the evaporation pressure. The compressor power indicates the amount of energy provided to the compressor, that is, the power input required for the operation of the compressor. The exhaust pressure is the pressure reached by the refrigerant after compression, which is usually close to the condensing pressure. The exhaust refrigerant flow rate refers to the flow rate of the refrigerant discharged by the compressor per unit time.

[0115] The vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters are input into a pre-built heat exchanger model to obtain the heat exchanger working parameters of the air-conditioning refrigeration system output by the heat exchanger model, wherein the heat exchanger working parameters include the outlet temperature and heat exchange capacity of the heat exchanger in the air-conditioning refrigeration system.

[0116] The heat exchanger model (evaporator model and condenser model) provided in the embodiment of the present invention can be divided into a single-phase region and a two-phase region according to the state of the refrigerant, wherein the single-phase region includes an overheating region and a supercooling region. The overheating region refers to the region where the refrigerant is in a gaseous state and the temperature is higher than the saturation temperature. The supercooling region refers to the region where the refrigerant is in a liquid state and the temperature is lower than the saturation temperature. The two-phase region represents the region where the refrigerant exists in both liquid and gaseous states and is in the process of evaporation or condensation. When calculating the characteristics of each region, the energy change of each region is calculated by the energy conservation equation to ensure the conservation of energy in the system. The heat transfer characteristics of each region are calculated by the fluid heat transfer equation to associate the heat exchange between the refrigerant and the heat exchanger. By coupling these two equations, the length of each region and the air outlet temperature can be determined, and finally the state of the refrigerant at the outlet of the heat exchanger can be obtained. A parallel flow heat exchanger can be used in the carriage of a rail vehicle to adjust the temperature of the interior environment. A tube-fin heat exchanger can be used outside the carriage of a rail vehicle to meet the heat exchange requirements of the exterior environment.

[0117] The heat transfer formula and mass flow formula of the heat exchanger model provided in the embodiment of the present invention may be as follows:

[0118]

[0119]

[0120]

[0121] Where Q is the heat transfer capacity of the heat exchanger; k is a constant; k0 is the heat transfer coefficient of the heat exchanger based on the outer area of ​​the tube; A is the heat transfer area outside the heat exchanger tube; t r is the saturated refrigerant temperature; t a1 ,ta2 is the air inlet and outlet temperature; q m is the mass flow rate at the compressor outlet; q m1 Mass flow rate in heat exchanger; h r1 、h r2 is the heat exchanger inlet and outlet enthalpy; q ma is the air mass flow rate; c is the specific heat capacity of air.

[0122] The input parameters of the heat exchanger model provided in the embodiment of the present invention also include the refrigerant flow rate and the inlet temperature, and the output parameters are the outlet temperature and the heat exchange amount. Among them, the refrigerant flow rate determines the amount of refrigerant for heat exchange in the heat exchanger. The inlet temperature includes the refrigerant inlet temperature and the heat exchange medium (air) inlet temperature. The outlet temperature includes the refrigerant outlet temperature and the heat exchange medium (air) outlet temperature. The heat exchange amount indicates the amount of heat transferred by the heat exchanger within a certain period of time.

[0123] The vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters are input into a pre-built thermal expansion valve model to obtain the thermal expansion valve working parameters of the air-conditioning refrigeration system output by the thermal expansion valve model, wherein the thermal expansion valve working parameters include the valve opening of the thermal expansion valve in the air-conditioning refrigeration system.

[0124] The basic model formula of the thermal expansion valve model provided by the embodiment of the present invention is as follows:

[0125]

[0126] When the system is stable, ;

[0127] Where m is a simplified mass point; y is the spring displacement; k1 is the elastic coefficient of the adjustable spring; k2 is the elastic coefficient of the base spring; A d is the area of ​​low pressure acting on the diaphragm; F1 is the adjustable spring force; F2 is the base spring force; p b is the outlet pressure on the low pressure side.

[0128] The input parameters of the thermal expansion valve model provided by the embodiment of the present invention also include: temperature of the temperature-sensing package and spring preload, and the output parameter is valve opening. The temperature of the temperature-sensing package reflects the temperature signal felt by the thermal expansion valve and is positively correlated with the refrigerant temperature at the outlet of the evaporator. The spring preload is the initial setting force of the spring inside the thermal expansion valve. The valve opening determines the flow rate of the refrigerant through the thermal expansion valve.

[0129] The working parameters output by the compressor model, heat exchanger model and thermal expansion valve model in the embodiment of the present invention are helpful for the subsequent accurate calculation of cooling demand, thereby realizing precise control of the air conditioning hot air bypass of the air-conditioning refrigeration system, effectively reducing the number of starts and stops of the compressor and reducing energy consumption.

[0130] Optional, in the above Figure 4 On the basis of one or more corresponding embodiments, another optional embodiment provided by the embodiment of the present invention is to obtain the target cooling demand calculation result of the rail vehicle at the current moment based on the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature, using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters, which may specifically include:

[0131] The temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature is used to obtain the initial cooling demand calculation result of the rail vehicle at the current moment.

[0132] Specifically, the embodiment of the present invention can input the current return air temperature in the rail vehicle and the preset target temperature into a PID controller, and the PID controller calculates the initial cooling demand calculation result based on the temperature error between the return air temperature in the vehicle and the preset target temperature.

[0133] Optionally, the calculation logic of the PID controller provided in the embodiment of the present invention can be as follows: Figure 7 As shown, V_BTV is the compensation constant; V_DTETAS is the difference; V_CTAS is the cooling or heating calculation value; P represents proportional control; I represents integral control; HI represents the heating need; CI represents the cooling need; Supply_air represents the supply air temperature in the car; Return_air represents the return air temperature in the car; and Set_point represents the target temperature.

[0134] Optionally, in the embodiment of the present invention, the temperature error between the vehicle return air temperature and the preset target temperature may be input into the following formula:

[0135]

[0136] Get the initial cooling demand calculation result of the rail vehicle at the current moment, where CN is the initial cooling demand calculation result, K p is the proportionality coefficient, K I is the integration coefficient, K D is the differential coefficient, T e is the temperature error.

[0137] The cooling demand influencing parameters are calculated using the exhaust pressure and discharge refrigerant flow of the compressor, the outlet temperature and heat transfer capacity of the heat exchanger, and the valve opening of the thermal expansion valve.

[0138] The embodiment of the present invention can pre-build the empirical function according to the operating characteristics of the actual system and experimental data. , where Pc is the exhaust pressure of the compressor, is the discharge refrigerant flow rate of the compressor, T out is the outlet temperature of the heat exchanger, Q is the heat exchange capacity of the heat exchanger, and α is the valve opening of the thermal expansion valve. In actual operation, the exhaust pressure and discharge refrigerant flow rate of the compressor, the outlet temperature and heat exchange capacity of the heat exchanger, and the valve opening of the thermal expansion valve are substituted into the empirical function to calculate the cooling demand influencing parameters.

[0139] Optionally, the empirical function can be specified as:

[0140] , where a 1， a 2， a 3， a4 and a5 are coefficients obtained by fitting the experimental data.

[0141] The initial cooling demand calculation result is corrected using the cooling demand influencing parameter to obtain the target cooling demand calculation result of the rail vehicle at the current moment.

[0142] Optionally, the embodiment of the present invention may add the cooling demand influencing parameter to the initial cooling demand calculation result to obtain the target cooling demand calculation result of the rail vehicle at the current moment.

[0143] Optionally, the embodiment of the present invention may perform a weighted summation of the cooling demand influencing parameter and the initial cooling demand calculation result to obtain the target cooling demand calculation result of the rail vehicle at the current moment.

[0144] The embodiment of the present invention calculates and corrects the cooling demand by analyzing the temperature error of the rail vehicle and combining the parameters of each component of the air-conditioning system, which helps to achieve precise control of the air-conditioning hot air bypass by accurately analyzing and dynamically adjusting the cooling demand, thereby improving the efficiency and stability of the air-conditioning refrigeration system.

[0145] Although operations are depicted in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order.Multitasking and parallel processing may be advantageous under certain circumstances.

[0146] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0147] Corresponding to the above method embodiment, the embodiment of the present invention also provides an air conditioning hot air bypass control device for a rail vehicle, the structure of which is as follows: Figure 8As shown, it may include: a target operating state parameter obtaining unit 10, a refrigeration component working parameter obtaining unit 20, a target cooling demand calculation result obtaining unit 30, a PWM control signal obtaining unit 40 and a hot gas bypass valve control unit 50.

[0148] The target operating state parameter obtaining unit 10 is used to obtain the target operating state parameters of the rail vehicle at the current moment, wherein the target operating state parameters include the indoor and outdoor temperature parameters of the rail vehicle and the operating pressure parameters of the air-conditioning and refrigeration system, and the operating pressure parameters of the air-conditioning and refrigeration system are related to the refrigerant flow of the hot gas bypass valve in the air-conditioning and refrigeration system of the rail vehicle.

[0149] The refrigeration component working parameter obtaining unit 20 is used to obtain the compressor working parameters, heat exchanger working parameters and thermal expansion valve working parameters of the air conditioning refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air conditioning refrigeration system operating pressure parameters.

[0150] The target cooling demand calculation result obtaining unit 30 is used to obtain the target cooling demand calculation result of the rail vehicle at the current moment based on the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature, using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters.

[0151] The PWM control signal obtaining unit 40 is used to obtain a PWM control signal that matches the target cooling demand calculation result.

[0152] The hot gas bypass valve control unit 50 is used to control the opening of the hot gas bypass valve of the rail vehicle using a PWM control signal to adjust the refrigerant flow through the hot gas bypass valve at the next moment, so that the return air temperature in the vehicle at the next moment is adjusted to a preset target temperature.

[0153] Optionally, the PWM control signal acquisition unit 40 is specifically used to generate a low cooling demand PWM control signal when the target cooling demand calculation result is in a first preset percentage interval, wherein the low cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start a compressor and open one hot gas bypass valve; when the target cooling demand calculation result is in a second preset percentage interval, a medium cooling demand PWM control signal is generated, wherein the medium cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and open two hot gas bypass valves; when the target cooling demand calculation result is in a third preset percentage interval, a high cooling demand PWM control signal is generated, wherein the high cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and close one hot gas bypass valve; when the target cooling demand calculation result is in a fourth preset percentage interval, a maximum cooling demand PWM control signal is generated, wherein the maximum cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and close all hot gas bypass valves.

[0154] Optionally, the first preset percentage interval is 4% to 25%, the second preset percentage interval is 26% to 50%, the third preset percentage interval is 51% to 75%, and the fourth preset percentage interval is 75% to 100%.

[0155] Optionally, the in-vehicle and out-vehicle temperature parameters include the outdoor ambient temperature of the rail vehicle, the in-vehicle return air temperature and the in-vehicle supply air temperature, and the air-conditioning and refrigeration system operating pressure parameters include the condensing pressure and the evaporating pressure of the air-conditioning and refrigeration system.

[0156] Optionally, the air conditioning hot gas bypass control device of the rail vehicle may also include: an air conditioning refrigeration system start and stop control unit.

[0157] The air conditioning and refrigeration system start and stop control unit is used for, after the target operating state parameter obtaining unit 10 obtains the target operating state parameters of the rail vehicle at the current moment, when the ambient temperature outside the vehicle is lower than the first preset temperature threshold, stopping the operation of the air conditioning and refrigeration system and opening the fresh air damper of the rail vehicle to maintain the return air temperature in the vehicle at the preset target temperature; when the ambient temperature outside the vehicle is greater than the second preset temperature threshold, starting the air conditioning and refrigeration system to trigger the target operating state parameter obtaining unit 10.

[0158] The refrigeration component working parameter acquisition unit 20 is specifically used to input the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built compressor model, and obtain the compressor working parameters of the air-conditioning refrigeration system output by the compressor model, wherein the compressor working parameters include the exhaust pressure and the discharge refrigerant flow rate of the compressor in the air-conditioning refrigeration system; input the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built heat exchanger model, and obtain the heat exchanger working parameters of the air-conditioning refrigeration system output by the heat exchanger model, wherein the heat exchanger working parameters include the outlet temperature and heat exchange capacity of the heat exchanger in the air-conditioning refrigeration system; input the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built thermal expansion valve model, and obtain the thermal expansion valve working parameters of the air-conditioning refrigeration system output by the thermal expansion valve model, wherein the thermal expansion valve working parameters include the valve opening of the thermal expansion valve in the air-conditioning refrigeration system.

[0159] Optionally, the target cooling demand calculation result obtaining unit 30 is specifically used to obtain the initial cooling demand calculation result of the rail vehicle at the current moment by using the temperature error between the return air temperature in the rail vehicle at the current moment and the preset target temperature; calculate the cooling demand influencing parameters by using the exhaust pressure and exhaust refrigerant flow of the compressor, the outlet temperature and heat exchange capacity of the heat exchanger, and the valve opening of the thermal expansion valve; use the cooling demand influencing parameters to correct the initial cooling demand calculation result to obtain the target cooling demand calculation result of the rail vehicle at the current moment.

[0160] The present invention provides an air conditioning hot gas bypass control device for a rail vehicle, and the device is used to: obtain target operating state parameters of the rail vehicle at the current moment, wherein the target operating state parameters include indoor and outdoor temperature parameters of the rail vehicle and operating pressure parameters of the air conditioning refrigeration system, and the operating pressure parameters of the air conditioning refrigeration system are related to the refrigerant flow rate of the hot gas bypass valve in the air conditioning refrigeration system of the rail vehicle; obtain compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air conditioning refrigeration system at the current moment by using the indoor and outdoor temperature parameters and the operating pressure parameters of the air conditioning refrigeration system; obtain a target cooling demand calculation result of the rail vehicle at the current moment by using the compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters based on the temperature error between the indoor return air temperature of the rail vehicle at the current moment and a preset target temperature; obtain a PWM control signal matching the target cooling demand calculation result; and control the opening of the hot gas bypass valve of the rail vehicle by using the PWM control signal to adjust the refrigerant flow rate flowing through the hot gas bypass valve at the next moment, so that the indoor return air temperature at the next moment is adjusted to the preset target temperature. The present invention calculates the cooling demand of the rail vehicle by combining the temperature parameters inside and outside the vehicle and the operating pressure parameters of the air-conditioning refrigeration system, and uses a PWM control signal to adjust the refrigerant flow through the hot gas bypass valve, so that the hot gas bypass control of the rail vehicle can adapt to the load changes inside and outside the vehicle, thereby improving the energy-saving effect of the hot gas bypass.

[0161] Regarding the device in the above embodiment, the specific manner in which each unit performs the operation has been described in detail in the embodiment of the method, and will not be elaborated here.

[0162] The air conditioning hot gas bypass control device of the rail vehicle includes a processor and a memory. The above-mentioned target operating state parameter acquisition unit 10, the refrigeration component working parameter acquisition unit 20, the target cooling demand calculation result acquisition unit 30, the PWM control signal acquisition unit 40 and the hot gas bypass valve control unit 50 are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

[0163] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the cooling demand calculated by the integrated temperature and pressure parameters is adjusted by adjusting the kernel parameters, and the hot gas bypass valve is precisely controlled by the PWM control method, so that the hot gas bypass control of the rail vehicle can adapt to the load changes inside and outside the vehicle, and improve the energy saving effect of the hot gas bypass.

[0164] An embodiment of the present invention provides a computer-readable storage medium having a program stored thereon, and when the program is executed by a processor, the air conditioning hot air bypass control method of the rail vehicle is implemented.

[0165] An embodiment of the present invention provides a processor, which is used to run a program, wherein the air conditioning hot air bypass control method of the rail vehicle is executed when the program is run.

[0166] like Fig. 9 As shown, an embodiment of the present invention provides an electronic device 1000, which includes at least one processor 1001, at least one memory 1002 connected to the processor 1001, and a bus 1003; wherein the processor 1001 and the memory 1002 communicate with each other through the bus 1003; the processor 1001 is used to call the program instructions in the memory 1002 to execute the above-mentioned rail vehicle air conditioning hot air bypass control method. The electronic device in this article can be a server, a PC, a PAD, a mobile phone, an ECU (Electronic Control Unit), a VCU (Vehicle Control Unit), an MCU (Micro Controller Unit), an HCU (Hybrid Control Unit), etc.

[0167] The present invention also provides a computer program product, which, when executed on an electronic device, is suitable for executing a program of initializing steps of a method for controlling hot gas bypass of an air conditioner of a rail vehicle.

[0168] The present invention is described with reference to flowcharts and / or block diagrams of methods, apparatuses, electronic devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable device to generate a machine, so that the instructions executed by the processor of the computer or other programmable device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0169] In a typical configuration, an electronic device includes one or more processors (CPU), a memory, and a bus. The electronic device may also include an input / output interface, a network interface, and the like.

[0170] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip. The memory is an example of a computer-readable medium.

[0171] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0172] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the present invention are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards of relevant countries and regions.

[0173] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left" and "right" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the positions or elements referred to must have specific directions, be constructed and operate in specific directions. Therefore, they should not be understood as limitations of the present invention.

[0174] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. It should also be noted that the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0175] It should be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0176] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for controlling hot air bypass of an air conditioner in a rail vehicle, characterized in that: include: Obtaining target operating state parameters of the rail vehicle at the current moment, wherein the target operating state parameters include indoor and outdoor temperature parameters of the rail vehicle and operating pressure parameters of an air-conditioning and refrigeration system, and the operating pressure parameters of the air-conditioning and refrigeration system are related to the refrigerant flow rate of a hot gas bypass valve in the air-conditioning and refrigeration system of the rail vehicle; Obtaining the compressor operating parameters, heat exchanger operating parameters and thermal expansion valve operating parameters of the air-conditioning refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters, including: inputting the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built compressor model, obtaining the compressor operating parameters of the air-conditioning refrigeration system output by the compressor model, wherein the compressor operating parameters include the exhaust pressure and the discharge refrigerant flow rate of the compressor in the air-conditioning refrigeration system; inputting the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built heat exchanger model, obtaining the heat exchanger operating parameters of the air-conditioning refrigeration system output by the heat exchanger model, wherein the heat exchanger operating parameters include the outlet temperature and heat exchange capacity of the heat exchanger in the air-conditioning refrigeration system; inputting the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built thermal expansion valve model, obtaining the thermal expansion valve operating parameters of the air-conditioning refrigeration system output by the thermal expansion valve model, wherein the thermal expansion valve operating parameters include the valve opening of the thermal expansion valve in the air-conditioning refrigeration system; Based on the temperature error between the return air temperature in the vehicle at the current moment and the preset target temperature, the target cooling demand calculation result of the vehicle at the current moment is obtained by using the compressor operating parameters, the heat exchanger operating parameters and the thermal expansion valve operating parameters, which includes: obtaining the initial cooling demand calculation result of the vehicle at the current moment by using the temperature error between the return air temperature in the vehicle at the current moment and the preset target temperature; calculating the cooling demand influencing parameter by using the exhaust pressure and the exhaust refrigerant flow of the compressor, the outlet temperature and the heat exchange amount of the heat exchanger and the valve opening of the thermal expansion valve; and correcting the initial cooling demand calculation result by using the cooling demand influencing parameter to obtain the target cooling demand calculation result of the vehicle at the current moment; Obtaining a PWM control signal that matches the target cooling demand calculation result; The PWM control signal is used to control the opening of the hot gas bypass valve of the rail vehicle to adjust the refrigerant flow rate flowing through the hot gas bypass valve at a next moment, so that the return air temperature in the vehicle at the next moment is adjusted to the preset target temperature.

2. The method according to claim 1, characterized in that The obtaining of a PWM control signal matching the target cooling demand calculation result comprises: When the target cooling demand calculation result is within a first preset percentage interval, a low cooling demand PWM control signal is generated, wherein the low cooling demand PWM control signal is used to control the air conditioning refrigeration system to start a compressor and open one of the hot gas bypass valves; When the target cooling demand calculation result is within the second preset percentage interval, a medium cooling demand PWM control signal is generated, wherein the medium cooling demand PWM control signal is used to control the air conditioning refrigeration system to start two compressors and open two hot gas bypass valves; When the target cooling demand calculation result is within the third preset percentage interval, a high cooling demand PWM control signal is generated, wherein the high cooling demand PWM control signal is used to control the air conditioning refrigeration system to start two compressors and close one of the hot gas bypass valves; When the target cooling demand calculation result is within a fourth preset percentage interval, a maximum cooling demand PWM control signal is generated, wherein the maximum cooling demand PWM control signal is used to control the air-conditioning refrigeration system to start two compressors and close all the hot gas bypass valves.

3. The method according to claim 2, characterized in that The first preset percentage interval is 4% to 25%, the second preset percentage interval is 26% to 50%, the third preset percentage interval is 51% to 75%, and the fourth preset percentage interval is 75% to 100%.

4. The method according to claim 1, characterized in that: The in-vehicle and out-vehicle temperature parameters include the outdoor ambient temperature, the in-vehicle return air temperature and the in-vehicle supply air temperature of the rail vehicle, and the air conditioning and refrigeration system operating pressure parameters include the condensing pressure and the evaporating pressure of the air conditioning and refrigeration system.

5. The method according to claim 4, characterized in that After obtaining the target operating state parameters of the rail vehicle at the current moment, the method further includes: When the ambient temperature outside the vehicle is lower than a first preset temperature threshold, the air conditioning and refrigeration system is stopped, and the fresh air damper of the rail vehicle is opened to maintain the return air temperature inside the vehicle at a preset target temperature; When the ambient temperature outside the vehicle is greater than a second preset temperature threshold, the air conditioning and refrigeration system is started, and the step of obtaining the target operating state parameters of the rail vehicle at the current moment is re-executed.

6. An air conditioning hot gas bypass control device for a rail vehicle, characterized in that: include: target operating state parameter obtaining unit, refrigeration component working parameter obtaining unit, target cooling demand calculation result obtaining unit, PWM control signal obtaining unit and hot gas bypass valve control unit, The target operating state parameter obtaining unit is used to obtain the target operating state parameter of the rail vehicle at the current moment, wherein the target operating state parameter includes the indoor and outdoor temperature parameters of the rail vehicle and the operating pressure parameter of the air-conditioning and refrigeration system, and the operating pressure parameter of the air-conditioning and refrigeration system is related to the refrigerant flow rate of the hot gas bypass valve in the air-conditioning and refrigeration system of the rail vehicle; The refrigeration component working parameter obtaining unit is used to obtain the compressor working parameters, heat exchanger working parameters and thermal expansion valve working parameters of the air-conditioning refrigeration system under the influence of the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters, which includes: inputting the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built compressor model to obtain the compressor working parameters of the air-conditioning refrigeration system output by the compressor model, wherein the compressor working parameters include the exhaust pressure and the discharge refrigerant flow rate of the compressor in the air-conditioning refrigeration system; inputting the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built heat exchanger model to obtain the heat exchanger working parameters of the air-conditioning refrigeration system output by the heat exchanger model, wherein the heat exchanger working parameters include the outlet temperature and heat exchange capacity of the heat exchanger in the air-conditioning refrigeration system; inputting the vehicle indoor and outdoor temperature parameters and the air-conditioning refrigeration system operating pressure parameters into a pre-built thermal expansion valve model to obtain the thermal expansion valve working parameters of the air-conditioning refrigeration system output by the thermal expansion valve model, wherein the thermal expansion valve working parameters include the valve opening of the thermal expansion valve in the air-conditioning refrigeration system; The target cooling demand calculation result obtaining unit is used to obtain the target cooling demand calculation result of the rail vehicle at the current moment based on the temperature error between the return air temperature in the vehicle at the current moment and the preset target temperature, using the compressor working parameters, the heat exchanger working parameters and the thermal expansion valve working parameters, including: obtaining the initial cooling demand calculation result of the rail vehicle at the current moment by using the temperature error between the return air temperature in the vehicle at the current moment and the preset target temperature; calculating the cooling demand influencing parameter by using the exhaust pressure and the exhaust refrigerant flow of the compressor, the outlet temperature and the heat exchange amount of the heat exchanger and the valve opening of the thermal expansion valve; and correcting the initial cooling demand calculation result by using the cooling demand influencing parameter to obtain the target cooling demand calculation result of the rail vehicle at the current moment; The PWM control signal obtaining unit is used to obtain a PWM control signal matching the target cooling demand calculation result; The hot gas bypass valve control unit is used to control the opening of the hot gas bypass valve of the rail vehicle using the PWM control signal to adjust the refrigerant flow passing through the hot gas bypass valve at the next moment, so that the return air temperature in the vehicle at the next moment is adjusted to the preset target temperature.

7. A computer-readable storage medium having a program stored thereon, characterized in that: When the program is executed by a processor, the air conditioning hot gas bypass control method for a rail vehicle according to any one of claims 1 to 5 is implemented.

8. An electronic device, characterized in that: The electronic device includes at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other via the bus; the processor is used to call program instructions in the memory to execute the air conditioning hot air bypass control method for a rail vehicle as described in any one of claims 1 to 5.

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