Automobile environment wind tunnel main fan motor and frequency converter temperature and humidity adjusting system

Abstract

The present application relates to the technical field of automobile environment wind tunnel safe operation, and discloses a kind of automobile environment wind tunnel main fan motor and frequency converter temperature and humidity adjusting system, including being located in the inside of wind tunnel main fan and with the motor and frequency converter connected with main fan, main fan is equipped with shell, motor is connected with frequency conversion control cabinet, and motor is located in shell, frequency converter is located in frequency conversion control cabinet;Wind tunnel is connected with fresh air humidity control system, and drying fresh air pipe is arranged in fresh air humidity control system, and further include motor temperature and humidity adjusting system and frequency converter temperature and humidity adjusting system, drying fresh air valve is arranged on drying fresh air pipe, motor temperature and humidity adjusting system includes motor humidity control fresh air humidifier, motor humidity control fresh air heat exchanger and motor humidity control fresh air valve connected in sequence by pipeline, motor humidity control fresh air humidifier is connected with drying fresh air valve, and motor humidity control fresh air valve is connected with the inside of shell. To solve the problem that the motor and frequency converter of main fan in existing wind tunnel are prone to failure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of safe operation of automobile environment wind tunnel, and particularly relates to a motor and frequency converter temperature and humidity adjusting system of automobile environment wind tunnel main fan. BACKGROUND

[0002] The automobile environment wind tunnel is a very important laboratory in automobile research and development. The inside of the wind tunnel can simulate the real external climate environment. The temperature can simulate -40-60 DEG C, the humidity can simulate 5-95% relative humidity, the wind speed can simulate 0-200 km / h, and the rain and snow simulation, sunlight simulation, etc. are carried out to perform extreme environment test on the automobile in the wind tunnel, such as high temperature heat balance / heat damage test, air conditioning cooling / heating test, low temperature cold start test, rain and snow test, etc. At the same time, the rotating drum arranged on the ground of the wind tunnel can make the automobile in the wind tunnel simulate the road driving state and ensure that the resistance of the automobile driving on the rotating drum is consistent with the resistance of the automobile driving on the real road.

[0003] The main fan is a major equipment for automobile environment wind tunnel test. The accuracy of the circulating wind speed and the rapidity of the adjustment provided by the main fan directly reflect the accuracy of the automobile environment test. The maximum power of the main fan under test state is as high as 1000kw, and the maximum rotating speed is 600r / min. The blade material is mostly aluminum alloy. The cost of a set of main fan of automobile environment wind tunnel is as high as tens of millions of yuan. Once the main fan is damaged, the maintenance cost is high and the maintenance period is long. For example, when the motor of the main fan is damaged, the maintenance period is as long as half a year, which brings huge economic loss during this period. However, due to the poor working environment of the main fan, the temperature in the wind tunnel is -40-60 DEG C, the humidity is 5-95%, and the rain and snow test is also accompanied, which increases the possibility of damage of the main fan.

[0004] The main fan mainly includes a motor and a frequency converter. Since the maximum power of the main fan during operation can reach 1000kw, a large amount of heat will be generated by the motor and the frequency converter. Although the motor and the frequency converter of the main fan are currently equipped with a cooling system, there are still many problems. For example, although the frequency converter cooling system is provided with a water cooling branch for the heat generating unit of the frequency converter, the temperature control accuracy of the frequency converter cooling system is poor. During use, the heat generating unit and the control unit of the frequency converter are prone to condensation. The condensation will flow along the connecting pipe to the circuit board, causing short circuit and other accidents. The motor is installed in the main fan shell. The cooling of the motor is usually achieved by air cooling to reduce the temperature of the air in the main fan shell, and then to cool the motor winding. However, the cooling air pipe also has the problem that the external humid air penetrates into the main fan shell, and the condensation or icing is easily generated on the inner wall of the main fan shell. The condensation or icing is easy to rust the steel parts, and the condensation is also easy to flow to the motor coil. Even if the motor coil is provided with an insulation layer, if used for a long time, the insulation will deteriorate, which will cause short circuit and damage. SUMMARY

[0005] The present invention aims to provide a temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel, in order to solve the problem of easy failure of the motor and frequency converter of the main fan in the existing wind tunnel.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a temperature and humidity control system for a main fan motor and frequency converter in an automotive environmental wind tunnel, comprising a main fan located inside the wind tunnel and a motor and frequency converter connected to the main fan. The main fan is fitted with a housing, the motor is connected to a frequency converter control cabinet and is located inside the housing, and the frequency converter is located inside the frequency converter control cabinet; the wind tunnel is connected to a fresh air humidity control system, which includes a drying fresh air duct, and further includes a motor temperature and humidity control system and a frequency converter temperature and humidity control system. The drying fresh air duct is equipped with... The dry fresh air valve and the motor temperature and humidity control system include a motor-controlled humidity fresh air humidifier, a motor-controlled humidity fresh air heat exchanger, and a motor-controlled humidity fresh air valve connected in sequence through pipes. The motor-controlled humidity fresh air humidifier is connected to the dry fresh air valve, and the motor-controlled humidity fresh air valve is connected to the interior of the housing. The inverter temperature and humidity control system includes an inverter steam humidifier and an inverter fresh air humidity control heat exchanger connected in sequence through pipes. The inverter steam humidifier is connected to the dry fresh air valve, and the inverter fresh air humidity control heat exchanger is connected to the interior of the inverter control cabinet.

[0007] The beneficial effects of this solution are as follows: It innovatively draws treated, dry, low-temperature fresh air from the existing fresh air humidity control system inside the wind tunnel and divides the fresh air into two paths. One path, after temperature and humidity control treatment, is sent into the main fan housing to regulate the temperature and humidity of the motor's operating environment. This ensures the motor operates under optimal temperature and humidity conditions, preventing condensation from damaging the circuitry and further ensuring the motor's operational safety, thus reducing the possibility of motor damage. The other path, after temperature and humidity control treatment, is sent into the frequency converter control cabinet to regulate the temperature and humidity of the various heat-generating units and components within the frequency converter. This ensures the frequency converter operates in an optimal environment, prevents internal condensation, and further dissipates heat from components not connected to a cooling system, further reducing the likelihood of frequency converter damage.

[0008] Furthermore, the dry fresh air in the existing fresh air humidity control system 300 is dehumidified at low temperatures, with a temperature of 10℃ and a dew point temperature as low as -45℃. Therefore, directly using the dry fresh air from the existing fresh air humidity control system can not only reduce the complexity of the system structure, but also better control the humidity of the extremely dry, low-temperature fresh air.

[0009] Preferably, a motor coil heating device is connected to the motor, and the motor coil heating device remains operational during motor operation and for 10 minutes after the motor is turned off.

[0010] Preferably, it also includes a water cooling system, which includes an inverter water cooling heat exchanger and a water pump connected to each other, and the water pump is connected to a water deionization exchange device; the water deionization exchange device deionizes and purifies the chilled water, and then cools the inverter through a deionized water pipe located inside the inverter control cabinet, and the deionized water pipe is equipped with an inverter water cooling temperature sensor.

[0011] Preferably, it also includes an air-cooling system, which includes an interconnected motor air-cooled heat exchanger and a cooling fan. The cooling fan is connected to a cooling duct, and the other end of the cooling duct is connected to the inside of the main fan casing.

[0012] Preferably, the cooling duct is also connected to a motor air-cooling pressure sensor, an exhaust fan, and a motor air-cooling pressure relief valve. The motor air-cooling pressure relief valve is in the open state when the main fan is running, and the exhaust fan is a variable frequency fan.

[0013] Preferably, a dry fresh air fan, a dry fresh air volume regulating valve, and a dry fresh air volume sensor are also provided between the dry fresh air valve and the fresh air humidity control system.

[0014] Preferably, a motor-cooled humidity sensor is installed inside the main fan casing, a motor coil temperature sensor is installed on the motor windings, and an inner wall temperature sensor is installed on the inner wall of the casing; when the wind tunnel test environment temperature is lower than a first threshold, the internal temperature of the casing is controlled to always be higher than the dew point temperature corresponding to the humidity of the external and internal environments.

[0015] Preferably, the frequency converter control cabinet includes an AFE unit IGBT stack heat exchange module, an MC unit IGBT stack heat exchange module, and a dv / dt filter heat exchange module. The AFE unit IGBT stack heat exchange module is connected to an AFE unit IGBT stack heat exchange module temperature sensor, the MC unit IGBT stack heat exchange module is connected to an MC unit IGBT stack heat exchange module temperature sensor, and the dv / dt filter heat exchange module is connected to a dv / dt filter heat exchange module temperature sensor.

[0016] Preferably, it also includes a motor-controlled humidity sensor for fresh air, which is disposed between the motor-controlled humidity humidifier and the motor-controlled humidity heat exchanger.

[0017] The benefits of this solution are:

[0018] Based on the characteristics of large inertia and large delay in the control process between the opening degree of the motor-controlled humidity flow regulating valve and the actual humidity value of the area where the motor is located, a motor-cooled humidity sensor is connected between the motor-controlled humidity fresh air humidifier and the motor-controlled humidity fresh air heat exchanger. The motor-cooled humidity sensor obtains the actual humidity value of the motor-controlled humidity fresh air in a timely manner, that is, the actual humidity value of the humidity-controlled fresh air about to enter the area where the motor is located. Utilizing the fast response control characteristics between the actual humidity value of the motor-controlled humidity fresh air and the opening value of the motor-controlled humidity flow regulating valve, and based on the transfer function between the actual humidity value of the motor-controlled humidity fresh air and the actual humidity value of the area where the motor is located, obtained from experiments, fast response control of the opening value of the motor-controlled humidity flow regulating valve is achieved. Meanwhile, based on the complexity of closed-loop feedback control, a further proposal is made to reduce the order of the high-order inertial transfer function between the actual humidity value of the fresh air controlled by the motor and the actual humidity value of the area where the motor is located. The high-order inertial gain element is equivalent to a simple gain element, thereby making the entire controlled object a first-order inertial delay element with gain. For the equivalent first-order inertial delay element with gain, precise control can be achieved by using PID control, thus solving the problem that the control of ambient air humidity in the area where the motor is located is difficult and affects the control operation of condensate discharge from the motor.

[0019] Preferably, it also includes a frequency converter humidity sensor for fresh air, which is disposed between the frequency converter humidity humidifier and the frequency converter humidity heat exchanger. Attached Figure Description

[0020] Figure 1 These are schematic diagrams of the wind tunnels in the front view of Embodiments 1 and 2 of the present invention;

[0021] Figure 2 These are schematic diagrams of the motor and frequency converter temperature and humidity control system in Embodiments 1 and 2 of the present invention;

[0022] Figure 3 This is a schematic diagram of the humidity control strategy for the area where the motor is located in Embodiment 3 of the present invention;

[0023] Figure 4 This is an equivalent schematic diagram of the humidity control strategy for the area where the motor is located in Embodiment 3 of the present invention. Detailed Implementation

[0024] The following detailed description illustrates the specific implementation method:

[0025] The reference numerals in the accompanying drawings include: First corner 101, Second corner 102, Third corner 103, Fourth corner 104, Nozzle 105, Absorption chamber 106, Insulation plate 107, Collection port 108, Tracked drum pit cover 109, Drum 110, Drum pit 111, Main fan 112, Main heat exchanger 113, Sunlight simulation system 114, Wind tunnel temperature sensor 115, Wind tunnel humidity sensor 116, Motor air-cooled water flow regulating valve 201, Motor air-cooled heat exchanger 202, Motor air-cooled temperature sensor 203, Cooling fan 204, Motor humidity-controlled fresh air valve. 205. Motor-controlled humidity fresh air temperature sensor; 206. Motor-controlled humidity fresh air water-cooled regulating valve; 207. Motor-controlled humidity fresh air heat exchanger; 208. Motor-controlled humidity fresh air humidity sensor; 209. Motor-controlled humidity airflow regulating valve; 210. Motor-controlled humidity fresh air humidifier; 211. Inverter-controlled humidity fresh air airflow regulating valve; 212. Inverter-controlled humidity fresh air humidifier; 213. Inverter-controlled humidity fresh air humidity sensor; 214. Drying fresh air fan; 215. Drying fresh air airflow regulating valve; 216. Drying fresh air airflow sensor; 217. Drying fresh air valve; 218. Inverter-controlled humidity fresh air heat exchanger; 219. Inverter-controlled humidity fresh air... 220 Water-cooled regulating valve, 221 Inverter humidity control fresh air temperature sensor, 222 Exhaust fan, 223 Motor air-cooled pressure relief valve, 224 Main fan blades, 225 Main fan support structure, 226 Main fan tail cone, 227 Motor, 228 Motor coil temperature sensor, 229 Housing inner wall temperature sensor, 230 Motor coil heating device, 231 Inverter water-cooled water flow regulating valve, 232 Inverter water-cooled heat exchanger, 233 Inverter water-cooled temperature sensor, 234 Water pump, 235 Deionized water flow regulating valve, 236 Water deionization equipment, 237 Inverter control cabinet, 238 First cooling water Flow regulating valve 238, AFE unit IGBT stack heat exchange module 239, AFE unit IGBT stack heat exchange module temperature sensor 240, second cold water flow regulating valve 241, MC unit IGBT stack heat exchange module 242, MC unit IGBT stack heat exchange module temperature sensor 243, third cold water flow regulating valve 244, dv / dt filter heat exchange module 245, dv / dt filter heat exchange module temperature sensor 246, control circuit board 247, motor air-cooled pressure sensor 248, motor air-cooled humidity sensor 249, fresh air humidity control system 300.

[0026] Example 1

[0027] Example 1 is basically as shown in the appendix. Figures 1-2 As shown, a temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel is described. Figure 1 As shown, the wind tunnel is equipped with a circulating air duct, and a main fan 112 is installed inside the air duct, and as... Figure 2As shown, the internal structure of the main fan 112 mainly includes main fan blades 224, a main fan support structure 225, and a main fan tail cone 226. The main fan blades 224 are connected to a motor 227, which provides power for the rotation of the main fan blades 224 to generate a powerful airflow. A housing is fitted over the main fan 112, and the motor 227 is installed inside the housing. Simultaneously, the motor 227 is connected to a frequency converter, which provides different wind speed test environments for the wind tunnel by changing the operating efficiency of the motor 227. The motor 227 is connected to a frequency converter control cabinet 237, and the frequency converter is located within the frequency converter control cabinet 237.

[0028] During wind tunnel operation, the subsystems most prone to failure among the main fan 112 subsystems are motor 227 and frequency converter. Based on the existing main fan 112 operating system, which typically uses air cooling for motor 227 and water cooling for frequency converter, analysis revealed that: because motor 227 is cooled by introducing cold air through cooling ducts to cool the motor windings, and these ducts are not absolutely sealed, external humid air can seep into them. During low-temperature wind tunnel tests, the moisture entering the casing through the cooling ducts easily condenses or freezes on the inner wall of the casing. This condensation or freezing not only causes steel components to rust but also easily leads to condensation seeping into the motor coils and causing short circuits. When water-cooled pipes are used to cool the heating unit of the frequency converter, the pulse-type temperature control, which adjusts the valve opening only periodically, results in poor temperature control accuracy. The deviation between the set value and the actual value of the internal temperature of the housing can reach ±3℃. Since the temperature control target is the internal air temperature of the frequency converter control cabinet 237, if the internal humidity of the frequency converter control cabinet 237 is high, condensation is likely to form on the heating unit and control unit of the frequency converter due to the temperature control deviation. On the other hand, the water-cooled pipes inside the frequency converter control cabinet 237 are also prone to condensation on their outer surface due to the low internal chilled water temperature (usually between 0-6℃). This condensation can travel along the chilled water pipes to the circuit board, causing accidents such as short circuits in the control circuit board.

[0029] Based on the causes of the above-mentioned motor 227 and inverter failures, this system is equipped with a motor temperature and humidity control system and an inverter temperature and humidity control system. By introducing dry fresh air from the existing fresh air humidity control system 300 in the wind tunnel into the main fan 112 housing and the inverter control cabinet 237 respectively, the humidity and temperature of the environment where the motor 227 and inverter are located are controlled, thereby preventing condensation and preventing short circuits in the motor 227 or inverter, thus improving the safety of the main fan 112 operation. The fresh air humidity control system 300 for the wind tunnel is existing technology, such as the invention patent disclosed in application number CN202310485858.0. The fresh air humidity control system 300 first dries the outside fresh air at a temperature of 10°C, then controls the humidity of the fresh air by a humidifier installed inside the system, and finally introduces the humidity-controlled fresh air into the wind tunnel to achieve precise control of the humidity of the wind tunnel environment. In this embodiment, the introduced dry fresh air is achieved by connecting a branch pipe to the low-temperature dry fresh air duct of the fresh air humidity control system 300.

[0030] To better understand the operation of the main fan 112, the internal structure of the automotive environmental wind tunnel will be further described:

[0031] like Figure 1 As shown, the wind tunnel is equipped with a circulating air duct, which includes a first bend 101, a second bend 102, a third bend 103 and a fourth bend 104. The main fan 112 is installed between the second bend 102 and the third bend 103. The main fan 112 accelerates the air in the air duct to the wind speed required for the test and provides power for the automotive environmental wind tunnel test. A chamber 106 is located between the first corner 101 and the fourth corner 104. Chamber 106 serves as the testing chamber for the automotive environmental wind tunnel. Inside chamber 106 are an insulated panel 107, a tracked drum pit cover 109, a drum 110, and a drum pit 111. The insulated panel 107 ensures the test temperature is controlled within a set range. The drum 110 allows for simulated road dynamics testing of the vehicle. A sunlight simulation system 114 is installed directly above the drum 110 to enhance the diversity of the simulated testing environment. A nozzle 1 is located at one end of the air duct at the fourth corner 104 extending into chamber 106. 05. At the end of the air duct at the first corner 101 extending into the sump chamber 106, a collection port 108 is provided. At the third corner 103, a main heat exchanger 113 is provided. When the main fan 112 is working, the air continuously flows through the main heat exchanger 113 for heat exchange and cooling. After reaching the set temperature required for the test, the air is guided through the third corner 103 and the fourth corner 104 and sprayed out from the nozzle 105 into the sump chamber 106 to blow air onto the test vehicle in the sump chamber 106. The air is then guided through the collection port 108, the first corner 101, and the second corner 102 to the rear end of the main fan 112, thus completing one cycle.

[0032] like Figure 2As shown, the air-cooled system connected to motor 227 includes motor air-cooled heat exchanger 202 and cooling fan 204. Motor air-cooled heat exchanger 202 is a water-air heat exchanger. Cooling fan 204 sends the cooled air after passing through motor air-cooled heat exchanger 202 into the housing of main fan 112. Motor air-cooled heat exchanger 202 is connected to motor air-cooled water flow regulating valve 201. By regulating the flow rate of chilled water entering motor air-cooled heat exchanger 202, the heat exchange effect is controlled, thereby realizing the temperature of the cold air delivered by the air-cooled branch pipe. Motor air-cooled temperature sensor 203 is provided between motor air-cooled water flow regulating valve 201 and cooling fan 204 to achieve precise control of the temperature of the cold air about to enter the housing. The water cooling system connected to the frequency converter control cabinet 237 includes a frequency converter water-cooled heat exchanger 232 and a water pump 234. The water pump 234 leads the water cooled by the frequency converter water-cooled heat exchanger 232 to the heating unit of the frequency converter. The water pump 234 is connected to a water deionization exchange device 236 to deionize and purify the chilled water to ensure the safety of cooling the heating unit. The water deionization exchange device 236 is connected to a deionized water flow regulating valve 235, which regulates the flow rate of the circulating deionized water, thereby controlling the degree of cooling of the frequency converter by the deionized water. The frequency converter water-cooled heat exchanger 232 is connected to a frequency converter water-cooled water flow regulating valve 231, which regulates the flow rate of chilled water entering the frequency converter water-cooled heat exchanger 232.

[0033] like Figure 2 As shown, the drying fresh air duct is connected to a drying fresh air valve 218 via a branch pipe. Between the fresh air humidity control system 300 and the drying fresh air valve 218, a drying fresh air fan 215, a drying fresh air volume regulating valve 216, and a drying fresh air volume sensor 217 are sequentially installed. The drying fresh air fan 215 provides power to the drying low-temperature fresh air in the fresh air humidity control system 300, directing it to the motor 227 and the frequency converter. The drying fresh air volume regulating valve 216 adjusts the fresh air flow, and the drying fresh air volume sensor 217 monitors the airflow to the drying fresh air valve 218 in real time, achieving precise control. Furthermore, the drying fresh air valve 218 is a manual valve. Since the airflow distribution is relatively fixed when the drying fresh air in the fresh air humidity control system 300 is split into two paths and directed to the motor 227 and the frequency converter control cabinet 237 respectively, a lower-cost manual valve can be used for preset control.

[0034] The motor temperature and humidity control system includes a motor-controlled humidity fresh air humidifier 211, a motor-controlled humidity fresh air heat exchanger 208, and a motor-controlled humidity fresh air valve 205, connected sequentially via pipes. The motor-controlled humidity fresh air humidifier 211 is connected to the dry fresh air valve 218 to humidify the dry fresh air about to enter the main fan 112 housing. After humidification with water vapor, the temperature of the fresh air rises. The motor-controlled humidity fresh air heat exchanger 208 then cools the humidified fresh air, thereby achieving the purpose of controlling the humidity and temperature of the fresh air. The motor-controlled humidity fresh air valve 205 is connected to the air-cooled duct that is connected to the inside of the housing in the air-cooling system, enabling the opening and closing of the motor temperature and humidity control system. Simultaneously, after the main fan 112 stops, closing the motor-controlled humidity fresh air valve 205 prevents humidified air from entering the cooling duct and causing condensation on the inner wall of the cooling duct. A motor-controlled humidity fresh air temperature sensor 206 is installed between the motor-controlled humidity fresh air valve 205 and the motor-controlled humidity fresh air heat exchanger 208 to monitor the temperature of the fresh air after temperature control in real time. In addition, a motor-cooled air pressure sensor 248, an exhaust fan 222, and a motor-cooled air pressure relief valve 223 are connected to the cooling duct. The motor-cooled air pressure relief valve 223 is in the open state when the main fan 112 is running. The exhaust fan 222 is a variable frequency fan used to control the pressure inside the cooling duct, further ensuring the safety of system operation.

[0035] A motor-controlled humidity control fresh air humidifier 211 is connected to the existing fresh air humidity control system 300 via a motor-controlled humidity control steam flow regulating valve 210 to provide water vapor to the motor temperature and humidity control system. The motor-controlled humidity control fresh air heat exchanger 208 is a water-to-air heat exchanger, connected to a motor-controlled humidity control fresh air water-cooling regulating valve 207. Circulating cooling water is introduced into the motor-controlled humidity control fresh air heat exchanger 208 through the motor-controlled humidity control fresh air water-cooling regulating valve 207 to achieve temperature control of the dry fresh air. A motor-cooled humidity sensor 249 is installed inside the main fan 112 housing, a motor coil temperature sensor 228 is installed on the motor windings, and a housing inner wall temperature sensor 229 is installed on the inner wall of the housing to obtain real-time humidity of the internal environment, surface temperature of the motor coils, and inner wall temperature of the housing, respectively.

[0036] When the ambient temperature of the wind tunnel test is lower than the first threshold, it indicates that a low-temperature test is being conducted inside the wind tunnel. Based on the dew point temperature corresponding to the ambient humidity inside the casing (i.e., the air humidity of the environment where the motor 227 is located) obtained by the motor air-cooled humidity sensor 249, by controlling this dew point temperature to always be lower than the inner wall temperature of the casing obtained by the inner wall temperature sensor 229, it is possible to avoid the situation where, during the low-temperature test, the outer surface of the casing is in direct contact with the circulating airflow of the wind tunnel, causing the surface temperature of the inner wall of the casing to approach the low-temperature temperature of the circulating airflow in the wind tunnel. At the same time as the inner wall of the casing is low, there is also circulating airflow inside the casing. The dew point temperature of the airflow is usually higher than the temperature of the inner wall of the casing, which leads to a large amount of condensation or ice formation on the inner wall of the casing, resulting in rusting of the steel parts inside the casing and short circuits in the motor coils. Furthermore, to ensure that the dew point temperature corresponding to the ambient humidity inside the casing is always lower than the temperature of the inner wall of the casing, the temperature difference margin of the control delay is increased. Specifically, the dew point temperature corresponding to the ambient humidity inside the casing is less than the temperature of the inner wall of the casing - 10°C. In this embodiment, the temperature difference margin is 10°C, ultimately ensuring that the inner wall of the casing will not condense or freeze. In addition, in this embodiment, the first threshold is 15°C, meaning that the test environment temperature inside the wind tunnel is less than 15°C, indicating that the wind tunnel is in a low-temperature test environment. The reason this solution is designed to control humidity rather than dehumidify to prevent condensation is that the optimal humidity range for the normal operation of electrical components is 40-60%. Excessive humidity easily leads to condensation, while excessively low humidity easily leads to static electricity, which can also damage the circuit. Therefore, controlling the humidity of the fresh air better ensures the normal operation of the motor and reduces the occurrence of malfunctions. When the wind tunnel is conducting tests at ambient or high temperatures above 15°C, the humidity inside the casing is controlled at 50% to ensure that the motor windings are in an optimal humidity operating environment. After humidity and temperature control, fresh air is continuously blown into the motor housing, which can control the ambient temperature of the motor 227 at the optimal temperature of 25℃. At the same time, by controlling the temperature of the inner wall of the housing to always be higher than the dew point temperature of the inner environment of the housing, the purpose of preventing condensation on the inner wall of the housing can be achieved.

[0037] In addition, such as Figure 2As shown, a motor coil heating device 230 is installed on the motor winding. The motor coil heating device 230 is used to heat up the motor when the internal temperature of the casing is lower than the optimal operating temperature of the motor 227 (25°C) due to heat exchange caused by airflow inside the wind tunnel under extremely low temperature test conditions. For example, when conducting an extremely low temperature test at -40°C inside the wind tunnel, the internal temperature of the casing is also below zero. It is relatively difficult to maintain the environment of the motor 227 at 25°C using fresh air with temperature and humidity control. At this time, the motor coil heating device 230 can raise the temperature of the motor 227 to 25°C, which can further ensure that the motor 227 can operate at the appropriate temperature and extend its service life. It can also prevent condensation on the surface of the motor 227 by raising the temperature of the motor 227. Furthermore, the motor coil heating device 230 can continue to heat the motor 227 after the main fan 112 stops, further improving the anti-condensation effect. After the low-temperature test is completed and the main fan 112 is turned off, the temperature of the motor 227 will gradually decrease. However, when the main fan 112 stops running, the internal pressure of the cooling duct decreases, making it difficult to completely seal. Therefore, some humid air will enter the cooling duct and reach the motor winding area, generating condensation on the low-temperature motor winding. The added motor coil heating device 230 can be activated at this time to raise the surface temperature of the motor coil. This ensures that the surface temperature of the motor winding is kept higher than the dew point temperature of the internal environment of the casing for a period of time after the low-temperature test is shut down, thus preventing condensation on the surface of the motor winding. In this embodiment, the motor coil heating device 230 is controlled to continue working for 10 minutes after shutdown.

[0038] like Figure 2 As shown, the internal heating units of the frequency converter control cabinet 227 mainly include the AFE unit IGBT stack heat exchange module 239, the MC unit IGBT stack heat exchange module 242, and the dv / dt filter heat exchange module 245. In this embodiment, a frequency converter water-cooled temperature sensor 233 is provided between the water pump 234 and the frequency converter water-cooled heat exchanger 232. During the operation of the main fan 112, the temperature of the deionized water used for circulating cooling is controlled by the frequency converter water-cooled temperature sensor 233 to always be greater than the dew point temperature corresponding to the humidity of the frequency converter control cabinet 237. This prevents condensation on the outer surface of the pipes circulating deionized water in the frequency converter control cabinet 237. Condensation would flow along the deionized water pipes and contact the control circuit board 247 and each heat exchange module in the frequency converter, causing a short circuit.

[0039] Considering that the frequency converter should also operate in its optimal working environment, the temperature inside the frequency converter control cabinet 237 should be controlled at 20℃ and the humidity at 40%. This ensures that the control circuit board 247 inside the frequency converter control cabinet 237 can operate under optimal conditions of 25℃ and 40% humidity within a 20℃ working environment, thereby ensuring the optimal operating environment for the frequency converter and increasing its service life. When the internal temperature of the frequency converter control cabinet 237 is stable at 20℃ and the humidity is stable at 40%, the corresponding dew point temperature is 6℃ (which can be calculated using the dew point temperature calculation formula). The temperature of the deionized water should always be greater than 6℃ to avoid condensation on the outer wall of the deionized water pipe. Similarly, based on the temperature difference margin of the control delay, in this embodiment, the temperature of the deionized water is set to 15℃. The temperature of the deionized water is 9℃ higher than the dew point temperature of the internal environment of the frequency converter control cabinet 237 during operation, i.e., the temperature difference margin is 9℃, which ensures that the surface of the deionized water pipe entering the frequency converter control cabinet 237 will not condense. The deionized water enters the frequency converter control cabinet 237 in three ways. One way passes through the first cold water flow regulating valve 238 to precisely control the surface temperature of the AFE unit IGBT stack heat exchange module 239, and the AFE unit IGBT stack heat exchange module 239 is connected to the AFE unit IGBT stack heat exchange module temperature sensor 240. Another way passes through the second cold water flow regulating valve 241 to precisely control the surface temperature of the MC unit IGBT stack heat exchange module 242, and the MC unit IGBT stack heat exchange module 242 is connected to the MC unit IGBT stack heat exchange module temperature sensor 243. The third way passes through the third cold water flow regulating valve 244 to precisely control the surface temperature of the dv / dt filter heat exchange module 245, and the dv / dt filter heat exchange module 245 is connected to the dv / dt filter heat exchange module temperature sensor 246.

[0040] Finally, as Figure 2 As shown, the inverter temperature and humidity control system includes an inverter steam humidifier 213 and an inverter fresh air humidity control heat exchanger 219 connected in sequence via pipes. The inverter steam humidifier 213 is connected to a dry fresh air valve 218, and the inverter fresh air humidity control heat exchanger 219 is connected to the inside of the inverter control cabinet via pipes. The outlet of the inverter fresh air humidity control heat exchanger 219 is connected to an inverter humidity control fresh air temperature sensor 221. The inverter fresh air humidity control heat exchanger 219 is connected to an inverter humidity control fresh air water-cooled regulating valve 220. Similarly, the inverter steam humidifier 213 is connected to the humidifier in the fresh air humidity control system 300 via an inverter humidity control fresh air steam flow regulating valve 212. The dry fresh air in the fresh air humidity control system 300 is humidified by the inverter steam humidifier 213 and cooled by the inverter fresh air humidity control heat exchanger 219 before entering the inverter control cabinet 237.

[0041] Considering the optimal operating environment inside the frequency converter control cabinet 237, the temperature and humidity control system of the frequency converter in this embodiment controls the temperature of the dry fresh air at 20℃ and the humidity at 40%. Although the three main heat-generating units of the frequency converter—the AFE unit IGBT stack heat exchange module 239, the MC unit IGBT stack heat exchange module 242, and the dv / dt filter heat exchange module 245—are all connected to water-cooling systems for cooling, units with less heat generation, such as the control circuit board 247, are not connected to a temperature control system. Under prolonged operation in the wind tunnel or extreme conditions, the control circuit board 247 may also experience poor heat dissipation and damage. This embodiment, by introducing temperature- and humidity-controlled fresh air into the frequency converter control cabinet 237, not only provides an optimal operating environment for each unit of the frequency converter control cabinet 237 but also provides timely heat dissipation for components such as the control circuit board 247, reducing the possibility of damage to these components of the frequency converter. Specifically, low-temperature dry fresh air at 10°C is introduced from the existing fresh air humidity control system 300 through the dry fresh air valve 218, humidified by the frequency converter humidity control fresh air humidifier 213, cooled to 20°C by the frequency converter humidity control fresh air heat exchanger 219, and then enters the frequency converter control cabinet 237. After the fresh air blows through the various circuit components in the frequency converter, it flows out from the small holes on the cabinet plate of the frequency converter control cabinet 237.

[0042] In this embodiment, innovatively, treated, low-temperature fresh air is drawn from the existing fresh air humidity control system 300 inside the wind tunnel and divided into two paths. One path of dry fresh air, after temperature and humidity control treatment, is sent into the housing of the main fan 112 to control the temperature and humidity of the motor 227's operating environment. This ensures that the motor 227 operates in an optimal temperature and humidity environment, preventing condensation from damaging the circuitry and further ensuring the safety of the motor 227's operation, thus reducing the possibility of motor 227 damage. The other path of dry fresh air, after temperature and humidity control treatment, is sent into the inverter control cabinet 227 to control the temperature and humidity of the operating environment of the various heat-generating units and components in the inverter. This ensures that the inverter is in an optimal operating environment, prevents internal condensation, and further dissipates heat from components that are not connected to a cooling system, thereby further reducing the possibility of inverter damage. The existing fresh air humidity control system 300 uses dry fresh air that has been dehumidified at low temperatures, with a temperature of 10°C and a dew point as low as -45°C. Therefore, directly using the dry fresh air from the existing fresh air humidity control system 300 can not only reduce the complexity of the system structure, but also better control the humidity of extremely dry, low-temperature fresh air.

[0043] Example 2

[0044] like Figures 2-4 The temperature and humidity control system of the main fan motor and inverter of the automotive environmental wind tunnel shown is different from that of Embodiment 1 in that it also includes a motor humidity control fresh air humidity sensor 209 and an inverter humidity control fresh air humidity sensor 214.

[0045] like Figure 2 As shown, the motor-controlled humidity sensor 209 is positioned between the motor-controlled humidity humidifier 211 and the motor-controlled humidity heat exchanger 208; the inverter-controlled humidity sensor 214 is positioned between the inverter-controlled humidity humidifier 213 and the inverter-controlled humidity heat exchanger 219. Adding a humidity sensor between the humidifier and the heat exchanger further improves the accuracy of humidity control for the fresh air destined for the motor 227 or the inverter. In this embodiment, the principle of precise humidity control is illustrated using the motor-controlled humidity sensor 209 in the motor temperature and humidity control system as an example. The motor-controlled humidity sensor 209 promptly acquires the actual humidity value of the motor-controlled fresh air.

[0046] Based on the actual humidity value of the area where the motor is located and the set humidity value of the area where the motor is located, determine the deviation value between the humidity setting and the actual value;

[0047] The opening value of the motor-controlled humidity control valve is determined based on the deviation value and the actual humidity value of the fresh air controlled by the motor.

[0048] Before determining the opening value of the motor-controlled humidification steam flow regulating valve, a step reduction process is performed. The step reduction process is as follows:

[0049] Obtain the transfer function G1(s) between the opening value of the motor humidity control airflow regulating valve and the actual value of the motor humidity control fresh air humidity; obtain the transfer function G2(s) between the actual value of the motor humidity control fresh air humidity and the actual value of the humidity in the area where the motor is located; based on the transfer functions G1(s) and G2(s), determine the transfer function G4(s) between the actual value of the humidity in the area where the motor is located and the opening value of the motor humidity control airflow regulating valve.

[0050] And a reduced-order controller is determined based on the transfer function G2(s);

[0051] The transfer function G4(s) is reduced in order using a reduced-order controller to obtain the reduced-order transfer function G5(s);

[0052] The reduced transfer function G5 is subjected to PID control to determine the opening value of the motor-controlled humidification steam flow regulating valve.

[0053] Where: φ motor The actual humidity value of the area where the motor is located (from the motor-cooled humidity sensor 249), φ motor set Here, E(s) represents the humidity setpoint for the area where the motor is located, E(s) represents the deviation between the humidity setpoint and the actual humidity value of the area where the motor is located, and PID represents the PID calculation of the closed-loop control loop; φ airThe actual humidity value of the fresh air controlled by the motor (obtained by the fresh air humidity sensor 209) is given by U2(s), and the opening value of the steam flow regulating valve 210 is given by G1(s). G1(s) is the transfer function between the opening value of the steam flow regulating valve 210 and the actual humidity value of the fresh air controlled by the motor, and G1(s) is a first-order inertial transfer function with delay. G2(s) is the transfer function between the actual humidity value of the fresh air controlled by the motor and the actual humidity value of the area where the motor is located, and this transfer function is an nth-order inertial element. control G3(s) is the inertial element of the reduced-order controller, and K is the gain element of the reduced-order controller.

[0054] In this embodiment, G1(s) is obtained through a perturbation test using the step response method. Specifically, the opening degree u2(s) of the motor-controlled humidification steam flow regulating valve 210 changes stepwise from one value to another, and then the actual humidity value φ of the motor-controlled humidification fresh air in the dry fresh air introduction duct is collected over a period of time. air The change curve provides the transfer function of the first-order inertial band gain element. The G1(s) transfer function is specifically:

[0055]

[0056] In the formula, K1 is the gain from the opening of the motor-controlled humidity control valve to the actual value of the fresh air humidity, T1 is the inertial time from the opening of the motor-controlled humidity control valve to the actual value of the fresh air humidity, and τ1 is the delay time from the opening of the motor-controlled humidity control valve to the actual value of the fresh air humidity.

[0057] G2(s) is obtained using a test-based modeling method. Specifically, it involves acquiring the fresh air humidity input and output values ​​over a given period, performing system identification based on this measured data, and finally obtaining the transfer function of the higher-order inertial band gain based on the system identification results. The fresh air humidity input value is the actual humidity value φ inside the dry fresh air duct of the motor-controlled humidity system. air The fresh air humidity output value is the actual humidity value φ of the area where the motor is located. motor .

[0058] The transfer function of G2(s) is as follows:

[0059] G2(s) = K / (Ts+1) n

[0060] In the formula: T is the inertial time from the actual value of the fresh air humidity controlled by the motor to the actual value of the humidity in the area where the motor is located, and K is the gain from the actual value of the fresh air humidity controlled by the motor to the actual value of the humidity in the area where the motor is located.

[0061] Furthermore, the actual humidity value φ in the area where the motor, which requires precise control, is located can be derived. motorThe transfer function G4(s) exists between the motor-controlled humidified steam flow regulating valve 210 and the opening value u2(s), and the formula for calculating G4(s) is as follows:

[0062]

[0063] φ moto The transfer function between u2(s) further demonstrates the difficulty of achieving fast and accurate control between the two.

[0064] Based on this, a reduction-order control method for closed-loop feedback control is further proposed. Based on the transfer functions obtained from the actual control system operation, and combining PID control and reduction-order control, the high-order inertial gain element is equivalent to a simple gain element, thus transforming the entire controlled object into a first-order inertial delay element with gain. Then, PID control can be used to achieve precise control of the equivalent first-order inertial delay element with gain. The specific reduction-order equivalence process is as follows: Figures 3 to 4 The process is as follows:

[0065] First, the order n, gain K, and inertia time T can be determined based on G2(s), and then the order reduction controller F can be determined. control , and such Figure 3 As shown, G3(s) is the inertial element of the reduced-order controller, and K is the gain element of the reduced-order controller.

[0066] G3(s) = 1 / (Ts+1) n

[0067] Using a reduced-order controller F control The inertial element G3(s) in the equation reduces the order of G1(s) and G2(s). For example... Figure 4 As shown, after order reduction, the humidity control system for the entire motor area becomes a first-order inertial and delayed element with gain, and the transfer function G5(s) becomes:

[0068]

[0069] As can be seen from the transfer function G5(s), this transfer function is simply the result of changing the gain in the transfer function G1(s) from K1 to K1*K. Therefore, a simple PID controller can achieve good and accurate control for such a first-order inertial and delayed element after order reduction.

[0070] In this embodiment, given the large inertia and delay in the control process between the opening degree of the motor-controlled humidity regulating valve 210 and the actual humidity value of the area where the motor is located, a motor-cooled humidity sensor 249 is connected to the outlet end of the motor-controlled humidity fresh air humidifier 211. The actual humidity value φ of the motor-controlled humidity fresh air is obtained in a timely manner through the motor-cooled humidity sensor 249. air , φair This refers to the actual humidity value of the fresh air entering the area where the motor is located, using the actual humidity value φ of the fresh air controlled by the motor. air The rapid response control characteristics between the motor-controlled humidity control valve opening value u2(s) and the actual humidity value φ of the motor-controlled fresh air are obtained from experiments. air The actual humidity value φ of the area where the motor is located motor The transfer function between the motor and the humidity control valve is used to achieve rapid response control of the opening value u2(s) of the motor-controlled humidity flow regulating valve. Furthermore, based on the complexity of closed-loop feedback control, a reduction process is proposed for the high-order inertial transfer function G2(s) between the actual humidity value of the fresh air controlled by the motor and the actual humidity value of the area where the motor is located. This transforms the high-order inertial gain element into a simple gain element, making the entire controlled object a first-order inertial delay element with gain. For the equivalent first-order inertial delay element with gain, precise control can be achieved using PID control, thus solving the problem of difficult control of ambient air humidity in the area where the motor is located, which affects the control operation of the motor's condensate discharge.

[0071] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A temperature and humidity control system for a main fan motor and frequency converter in an automotive environmental wind tunnel, comprising a main fan installed inside the wind tunnel and a motor and frequency converter connected to the main fan, the main fan being fitted with a housing, the motor being connected to a frequency converter control cabinet and located inside the housing, and the frequency converter being located inside the frequency converter control cabinet; the wind tunnel is connected to a fresh air humidity control system, the fresh air humidity control system containing a drying fresh air duct, characterized in that: It also includes a motor temperature and humidity control system and a frequency converter temperature and humidity control system. A drying fresh air valve is installed on the drying fresh air duct. The motor temperature and humidity control system includes a motor humidity-controlled fresh air humidifier, a motor humidity-controlled fresh air heat exchanger, and a motor humidity-controlled fresh air valve connected in sequence through pipes. The motor humidity-controlled fresh air humidifier is connected to the drying fresh air valve, and the motor humidity-controlled fresh air valve is connected to the inside of the housing. The frequency converter temperature and humidity control system includes a frequency converter steam humidifier and a frequency converter fresh air humidity-controlled heat exchanger connected in sequence through pipes. The frequency converter steam humidifier is connected to the drying fresh air valve, and the frequency converter fresh air humidity-controlled heat exchanger is connected to the inside of the frequency converter control cabinet. A dry fresh air fan, a dry fresh air volume regulating valve, and a dry fresh air volume sensor are also installed between the dry fresh air valve and the fresh air humidity control system. It also includes a motor-controlled humidity sensor for fresh air, which is installed between the motor-controlled humidity humidifier and the motor-controlled humidity heat exchanger. It also includes a frequency converter humidity control fresh air humidity sensor, which is installed between the frequency converter steam humidifier and the frequency converter fresh air humidity control heat exchanger.

2. The temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel according to claim 1, characterized in that: A motor coil heating device is connected to the motor, and the motor coil heating device remains running during the operation of the motor and for 10 minutes after the motor is turned off.

3. The temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel according to claim 2, characterized in that: It also includes a water cooling system, which includes an interconnected inverter water cooling heat exchanger and a water pump, and the water pump is connected to a water deionization exchange device; the water deionization exchange device deionizes and purifies the chilled water, and then cools the inverter through a deionized water pipe located inside the inverter control cabinet, and the deionized water pipe is equipped with an inverter water cooling temperature sensor.

4. The temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel according to claim 3, characterized in that: It also includes an air-cooling system, which includes an interconnected motor air-cooled heat exchanger and a cooling fan. The cooling fan is connected to a cooling duct, and the other end of the cooling duct is connected to the inside of the main fan casing.

5. The temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel according to claim 4, characterized in that: The cooling duct is also connected to a motor air-cooling pressure sensor, an exhaust fan, and a motor air-cooling pressure relief valve. The motor air-cooling pressure relief valve is in the open state when the main fan is running, and the exhaust fan is a variable frequency fan.

6. The temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel according to claim 1, characterized in that: The main fan casing is equipped with a motor-cooled humidity sensor, a motor coil temperature sensor on the motor windings, and an inner wall temperature sensor on the inner wall of the casing. When the wind tunnel test environment temperature is lower than the first threshold, the internal temperature of the casing is controlled to always be higher than the dew point temperature corresponding to the internal ambient humidity.

7. The temperature and humidity control system for the main fan motor and frequency converter of an automotive environmental wind tunnel according to claim 6, characterized in that: The variable frequency control cabinet includes an AFE unit IGBT stack heat exchange module, an MC unit IGBT stack heat exchange module, and a dv / dt filter heat exchange module. The AFE unit IGBT stack heat exchange module is connected to an AFE unit IGBT stack heat exchange module temperature sensor, the MC unit IGBT stack heat exchange module is connected to an MC unit IGBT stack heat exchange module temperature sensor, and the dv / dt filter heat exchange module is connected to a dv / dt filter heat exchange module temperature sensor.

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