Compressor preheating control system, preheating method and air conditioning unit

Abstract

The compressor preheating control system comprises a main controller and a compressor frequency converter which are connected with each other, and the frequency converter is electrically connected with a motor winding of a compressor; the main controller and the frequency converter are configured in the mode that after the main controller receives a starting instruction, a preheating instruction is generated according to the real-time environment temperature and the shutdown duration of a compressor; and after receiving the preheating instruction, the frequency converter outputs low-frequency voltage to a motor winding of the compressor to preheat the compressor. The invention further provides a preheating method of the compressor preheating control system and an air conditioning unit. According to the compressor preheating control system, the preheating method and the air conditioning unit, preheating before the compressor is started is conducted through the frequency converter and the motor winding which are arranged on the unit, and after preheating is completed, normal driving and controlling of the compressor are conducted. The output power of the frequency converter directly reaches the motor winding, so that the heat loss is small, the heating efficiency is high, new components are not needed, the production efficiency and the product reliability are greatly improved, and the product manufacturing cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning unit, in particular to a compressor preheating control system, a preheating method and an air conditioning unit. BACKGROUND

[0002] The track subway variable frequency air conditioning unit usually uses a horizontal compressor. When the outdoor temperature is low, the lubricating oil and the refrigerant will be mutually soluble after the air conditioning unit is stationary overnight, and a large amount of refrigerant will be deposited in the crankcase of the compressor in a liquid state, which will cause the lubricating oil concentration to decrease and fail to meet the lubricating demand of the compressor, and will also cause liquid hammer when the compressor is started. In order to avoid damage to the compressor, the compressor needs to be preheated before starting to ensure the reliability of the system.

[0003] In the existing scheme, the track subway variable frequency air conditioning unit manufacturers usually wrap an electric heating belt with a heating power of about 70 W around the outer wall of the compressor, and the electric heating belt is powered to generate heat and conduct the heat to the inside of the compressor through the cylinder before the compressor is started.

[0004] In the existing scheme of adding an electric heating belt, the electric heating belt is wrapped around the outer wall of the compressor and is also exposed to the low-temperature environment, and the heat loss is large and the heat transfer coefficient is low. The power of the electric heating belt is usually limited and cannot be designed too large, which will result in low heating efficiency and long preheating period. At the same time, the addition of the electric heating belt component increases the cost, reduces the production efficiency, and also reduces the reliability. SUMMARY

[0005] The present application provides a compressor preheating control system, a preheating method and an air conditioning unit. In the present application, the frequency converter and the motor winding of the air conditioning unit are used to preheat the compressor before starting, and the normal driving and control of the compressor are performed after the preheating is completed. The output power of the frequency converter directly reaches the motor winding, the heat loss is small, the heating efficiency is high, and at the same time, no new component needs to be added, which greatly improves the production efficiency and product reliability, and also reduces the product manufacturing cost.

[0006] To solve the above technical problems, the present application first provides a compressor preheating control system, which adopts the following technical scheme:

[0007] A compressor preheating control system, comprising a main controller and a compressor frequency converter connected to each other, wherein the frequency converter is electrically connected to the motor winding of the compressor; and the main controller and the frequency converter are configured to,

[0008] After the main controller receives a starting instruction, the main controller generates a preheating instruction according to the real-time environmental temperature and the length of time when the compressor is stopped;

[0009] After the frequency converter receives the preheating instruction, the frequency converter outputs a low-frequency voltage to the motor winding of the compressor to preheat the compressor.

[0010] Further, the frequency converter outputs a sine wave voltage or an intermittent commutation direct current voltage with a frequency of 5-15 Hz to the motor winding after receiving the preheating instruction.

[0011] Further, the compressor is a horizontal compressor, and at least part of the motor winding is immersed in the compressor lubricating oil.

[0012] The second application object of the application is to provide a preheating method of a compressor preheating control system, which adopts the following technical scheme:

[0013] A preheating method of a compressor preheating control system, the preheating control system comprising a main controller and a compressor frequency converter connected with each other, and the frequency converter being electrically connected with a motor winding of a compressor; the main controller generates a preheating instruction and sends it to the frequency converter after receiving a start-up instruction according to a real-time ambient temperature and a compressor downtime.

[0014] The frequency converter outputs a low-frequency voltage to the motor winding of the compressor for compressor preheating after receiving the preheating instruction.

[0015] Further, the main controller generates a preheating instruction and sends it to the frequency converter when the outdoor ambient temperature is less than or equal to a first preset temperature and the compressor downtime is greater than or equal to a first preset time or a previous time.

[0016] Further, the main controller is provided with a corresponding relationship table of ambient temperature and preheating time, and the preheating time is obtained according to the real-time outdoor ambient temperature and the corresponding relationship table and sent to the frequency converter.

[0017] Further, the corresponding relationship table comprises:

[0018] When the outdoor ambient temperature is greater than 0℃ and less than or equal to 5℃, the preheating time is a minutes;

[0019] When the outdoor ambient temperature is greater than -5℃ and less than or equal to 0℃, the preheating time is b minutes;

[0020] When the outdoor ambient temperature is greater than -10℃ and less than or equal to -5℃, the preheating time is c minutes;

[0021] When the outdoor ambient temperature is greater than -20℃ and less than or equal to -10℃, the preheating time is d minutes;

[0022] Wherein, a < b < d < d.

[0023] Further, the preheating method of the compressor preheating control system according to claim 7, wherein the main controller is provided with a timing module, and the main controller controls to stop preheating according to the preheating time recorded by the timing module.

[0024] Further, the main controller is further configured to send a start instruction to the frequency converter directly when the compressor has run for more than a preset running time and has stopped for less than a first preset time.

[0025] The third inventive purpose of the present application is to provide an air conditioning unit, which adopts the following technical scheme:

[0026] An air conditioning unit is provided with a compressor preheating control system as described above and performs a preheating method of the compressor preheating control system as described above.

[0027] In summary, the compressor preheating control system, the preheating method and the air conditioning unit provided by the present application have the following advantages compared with the prior art:

[0028] 1. The compressor preheating is realized by using the frequency converter and the motor winding of the compressor, the lubricating oil is heated directly in the compressor, the heat loss is small, and the preheating efficiency is high;

[0029] 2. The preheating is directly realized by the motor winding, the preheating time is short, and the customer experience is high;

[0030] 3. The preheating is realized by using the operation heat of the existing components of the compressor, no new components are added, the cost is reduced, the production efficiency is improved, and the reliability is improved.

[0031] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are part of the present application and serve to provide a further understanding of the present application, the illustrative embodiments of the present application and the description thereof serve to explain the present application, but do not constitute an improper limitation of the present application. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0033] In the drawings:

[0034] Figure 1 is a connection schematic diagram of a compressor preheating control system of the present application;

[0035] In the drawings:

[0036] 1, vehicle controller; 2, main controller; 3, ambient temperature sensor; 4, frequency converter; 5, compressor; CN1, main controller and vehicle controller communication interface; CN2, main controller and frequency converter communication interface; CN3, frequency converter and main controller communication interface; CN4, ambient temperature sensor and main controller communication interface; P, frequency converter bus voltage positive input; N, frequency converter bus voltage negative input; U, frequency converter U-phase output interface; V, frequency converter V-phase output interface; W, frequency converter W-phase output interface.

[0037] It should be noted that the drawings and the written description are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but not to limit the scope of the present application.

[0039] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0040] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] The present application first provides a compressor preheating system, comprising a main controller 2 and a compressor frequency converter 4 connected to each other, the frequency converter 4 is electrically connected with the motor winding of the compressor 5; the main controller 2 and the frequency converter 4 are configured to,

[0042] After the main controller 2 receives the start-up instruction, a preheating instruction is generated according to the real-time ambient temperature and the length of time when the compressor 5 is stopped;

[0043] After the frequency converter 4 receives the preheating instruction, a low-frequency voltage is output to the motor winding of the compressor 5 for preheating the compressor 5.

[0044] A compressor preheating system provided in the present application can be widely used in equipment including but not limited to refrigerators, air conditioners, heat pumps, etc. that perform refrigerant heat exchange through the action of a compressor 5. In this embodiment, an air-conditioning unit, especially a vehicle-mounted air-conditioning unit, is taken as an example to introduce the specific composition structure and preheating method of the compressor preheating system provided in the present application.

[0045] A compressor preheating control system includes a main controller 2, such as Figure 1 As shown, the main controller 2 is connected to the vehicle controller 1 through the main controller and vehicle controller communication interface CN1. The vehicle controller 1 sends a control instruction for starting the air-conditioning unit to the main controller 2 through the main controller and vehicle controller communication interface CN1. The main controller 2 receives the control instruction and determines whether the received control instruction is to control the air-conditioning unit to operate in heating mode or cooling mode, and further determines whether the compressor 5 needs to be preheated.

[0046] In the air conditioning unit ( Figure 1 An ambient temperature sensor 3 is provided on the housing (not shown), and the ambient temperature sensor 3 is communicated with the main controller 2 via a CAD bus or a 485 communication bus, or is electrically connected to the ambient temperature sensor and the main controller communication interface CN4.

[0047] The main controller 2 is in communication with the inverter 4 of the compressor 5. The main controller is provided with a main controller-to-inverter communication interface CN2, and the inverter 4 is provided with an inverter-to-main controller communication interface CN3. The two interfaces are connected via a CAD bus or a 485 communication bus, but can be electrically connected.

[0048] The frequency converter 4 is electrically connected to the compressor 5, as shown in FIG. Figure 1 As shown, the inverter 4 is provided with an inverter bus voltage positive input P and an inverter bus voltage negative input N, which are used to power the inverter 4; an inverter U-phase output interface U, an inverter V-phase output interface V and an inverter W-phase output interface W are also provided. The inverter 4 is electrically connected to the compressor 5 through a three-phase interface. Furthermore, the inverter 4 can at least be electrically connected to the motor winding of the compressor 5, and output a sinusoidal wave voltage or an intermittent commutated DC voltage with an output frequency of 5-15Hz for preheating to the motor winding. Under this voltage mode, the motor winding operates to generate operating heat to preheat the compressor 5.

[0049] In this embodiment, the compressor 5 is a horizontal compressor. When static, part or most of the motor winding is immersed in the oil pool. The motor winding generates operating heat under the sinusoidal voltage or intermittent commutated DC voltage delivered by the inverter 4, and exchanges heat with the oil pool, thereby achieving preheating of the lubricating oil and effective evaporation of the refrigerant.

[0050] The main controller 2 receives the start-up instruction of the vehicle controller 1 through the main controller and vehicle controller communication interface CN1, judges the operation mode of the air conditioning unit, such as the refrigeration mode or the heating mode, obtains the real-time outdoor environment temperature provided by the environment temperature sensor 3 through the environment temperature sensor and main controller interface CN4, and judges whether the compressor 5 needs to be preheated according to the stop time of the compressor 5. If the compressor 5 does not need to be preheated, the main controller and frequency converter communication interface CN2 and the frequency converter and main controller communication interface CN3 are directly used to send the start-up operation instruction to the frequency converter 4. If the compressor 5 needs to be preheated, a preheating instruction is generated and sent to the frequency converter 4 through the interfaces CN3 and CN4. As described above, the frequency converter 4 executes corresponding actions according to the received instruction, such as executing the start-up instruction to control the compressor 5 to operate at the frequency in the instruction, or executing the preheating instruction to send a 5-15 Hz sine wave voltage or an intermittent commutation direct current voltage to the motor winding to make the motor winding operate under the voltage, while the compressor 5 does not operate, so that the motor winding generates operation heat to preheat the lubricating oil.

[0051] In the embodiment, after the main controller 2 receives the start-up instruction of the vehicle controller 1, the real-time outdoor environment temperature and the stop time of the compressor 5 are compared with the corresponding preset values to determine whether the compressor 5 needs to be preheated and the preheating time.

[0052] The main controller 2 is provided with a timer for counting the operation time and the stop time of the air conditioning unit, especially the compressor 5. The operation time here refers to the time for driving the refrigerant flow in the normal operation of the compressor 5 in the refrigeration or heating mode, and does not include the preheating time. After the main controller 2 receives the start-up instruction, the normal operation time and the stop time of the compressor 5 recorded by the timer before the current instruction are detected. If the normal operation time of the compressor 5 before the current start-up instruction is more than (equal to or greater than) the preset operation time, such as 30 min, and the stop time is less than the first preset time, such as 2 hours, the main controller 2 directly sends the start-up instruction to the frequency converter 4, the compressor 5 does not need to be preheated, and directly starts to execute the corresponding refrigeration or heating mode according to the start-up instruction.

[0053] It should be noted that the preset operation time and the first preset time can be adjusted according to the outdoor environment temperature. The preset operation time of 30 min and the first preset time of 2 h described in the embodiment are basic data, which are applicable to the environment temperature in the range of 10℃-26℃. When the environment temperature is lower than 10℃ (including), the environment temperature is low, the compressor 5 dissipates heat quickly, and the preset operation time and the first preset time are appropriately reduced to avoid the quick heat dissipation of the compressor 5 and the condensation of the lubricating oil. When the environment temperature is higher than 26℃ (including), the environment temperature is high, which is not conducive to the heat dissipation of the compressor 5, and the time required for the lubricating oil in the compressor 5 to cool down to the condensation point is long, so the preset operation time and the first preset time can be appropriately extended.

[0054] Preferably, the main controller 2 is provided with a variation curve of time and ambient temperature, the variation curve is related to the heat dissipation and cooling speed of the compressor 5 at different ambient temperatures, and the preset running time and the first preset time are different at different ambient temperatures. The variation curve can be divided into multiple sections, such as the variation curve can be divided into three continuous curves connected at both ends, the first section is when the ambient temperature is less than or equal to 10℃, the second section is when 10℃<ambient temperature<26℃, and the third section is when the ambient temperature is greater than or equal to 26℃.

[0055] In the first section, the preset running time and the first preset time are linearly shortened with the increase of the ambient temperature; in the second section, the preset running time and the first preset time are constant values and do not change with the ambient temperature; in the third section, the preset running time and the first preset time are linearly lengthened with the increase of the ambient temperature. Considering that the heat dissipation and cooling efficiency of the compressor 5 are different in low temperature (less than or equal to 10℃) and high temperature (greater than or equal to 26℃) environments, the slopes of the first section and the second section can be set to be different. Preferably, the second section can also be divided into intervals, and different slopes can be used in each interval. Similarly, the interval curve of the newly divided second section includes a horizontal line, that is, the preset running time and the first preset time do not change with the ambient temperature in the interval. The slopes of the curves in each section are determined according to the heat dissipation efficiency of the compressor 5 in the temperature interval, so as to accurately control the preheating operation.

[0056] Further, if the outdoor ambient temperature and the compressor 5 downtime do not meet the above conditions, further judgment is made. When the outdoor ambient temperature is less than or equal to the first preset temperature and the compressor 5 downtime is greater than or equal to the first preset time, the main controller 2 generates a preheating instruction and sends it to the frequency converter 4. The first preset temperature can be set to 5℃, and the first preset time is 2 hours as described above, that is, when the outdoor ambient temperature is less than or equal to 5℃ and the compressor 5 downtime is greater than or equal to 2h, it is determined that the compressor 5 needs to be preheated before this start-up, and the preheating instruction is sent to the frequency converter 4.

[0057] Preferably, the main controller 2 is provided with a corresponding relationship table of ambient temperature and preheating time, and a plurality of continuous ambient temperature intervals are set in the corresponding table, and each interval corresponds to a preheating time, such as:

[0058] When the outdoor ambient temperature is greater than or equal to 5℃, the preheating time is a minutes;

[0059] When the outdoor ambient temperature is greater than or equal to 5℃, the preheating time is a minutes;

[0060] When the outdoor ambient temperature is greater than or equal to 5℃, the preheating time is a minutes;

[0061] When -20℃ < outdoor environment temperature ≤ -10℃, the preheating time is d minutes;

[0062] Wherein, a < b < d < d.

[0063] In this embodiment, the corresponding relationship between the ambient temperature range and the preheating time is shown in Table 1:

[0064] Table 1: Corresponding relationship table of ambient temperature and preheating time

[0065] Ring temperature T Preheating time 0℃<T≤5℃ 3 min (a) -5℃<T≤0℃ 6 min (b) -10℃<T≤-5℃ 10 min (c) -20℃<T≤-10℃ 15 min (d)

[0066] The main controller 2 acquires the corresponding preheating time in the corresponding relationship table according to the acquired real-time outdoor environment temperature, and sends the acquired preheating time to the frequency converter 4 along with the preheating instruction, and the frequency converter 4 performs the corresponding preheating operation.

[0067] It should be noted that the preheating time of the compressor 5 shown in Table 1 is only an example. In actual application, the preheating time corresponding to different specifications, different rated power and different lubricating oil used by the compressor 5 is different.

[0068] After the main controller 2 sends the preheating instruction, the timer in the main controller 2 starts the preheating countdown. When the countdown is over, the main controller 2 sends the end preheating command to the frequency converter 4, and simultaneously sends the compressor 5 start (air conditioning unit start) command, operation mode and target frequency. The timer starts timing and records the running time of the compressor 5 for the next time the machine is started to judge whether preheating is needed.

[0069] As described above, the main controller 2 of the air conditioning unit connects the outdoor environment temperature sensor 3 through the CN4 interface to detect the outdoor environment temperature, and records the last time the compressor 5 runs and the time from shutdown to now. When the vehicle controller sends the refrigeration and heating mode command to the air conditioning main controller 2 through the vehicle controller and main controller interface CN1 port, the main controller 2 judges whether the compressor 5 needs to be preheated. If preheating is needed, the main controller 2 needs to send the preheating command and the preheating time to the compressor frequency converter 4 through the CN2 and CN3 communication ports in the above figure, and the main controller 2 performs preheating time countdown. When the countdown is over, the main controller 2 sends the end preheating command to the compressor frequency converter 4 and simultaneously sends the compressor 5 start command and target frequency; if it is judged that preheating is not needed, the main controller 2 directly sends the compressor 5 start command and target frequency to the compressor frequency converter 4.

[0070] In the embodiment, the compressor preheating control system and the specific preheating control method are introduced by taking the vehicle-mounted air conditioning unit as an example. However, the compressor preheating control system can be widely applied to any device using the compressor 5, including but not limited to any nature of air conditioning unit, refrigerator, heat pump system. According to the different use of the device, the connection mode, the setting position, etc. of each component of the compressor preheating control system described above can be adaptively adjusted, and the preheating control described above can be realized. It cannot be considered as a limitation of the application scope because of the above description. For example, when the compressor preheating control system described above is a general household air conditioner, the vehicle controller 1 does not need to be set, and the vehicle controller and the main controller interface CN1 do not need to be set on the main controller 2. The main controller 2 directly receives the start-up instruction, and performs the compressor preheating control according to the environmental temperature, the running time of the compressor 5 in the previous stage, the shutdown time, etc. as described above.

[0071] In summary, the compressor preheating control system, the preheating method and the air conditioning unit provided by the application have the following advantages compared with the prior art.

[0072] 1. The compressor preheating is realized by using the frequency converter and the motor winding of the compressor, the lubricating oil is directly heated in the compressor, the heat loss is small, and the preheating efficiency is high.

[0073] 2. The preheating is directly performed by the motor winding, the preheating time is short, and the customer experience is high.

[0074] 3. The preheating is realized by using the running heat of the existing components of the compressor, no new components are added, the cost is reduced, the production efficiency is improved, and the reliability is improved.

[0075] The above description is only the preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the scope of the technical solution of the application, and the equivalent embodiments with equivalent changes are equivalent. The embodiments in the above examples can be further combined or replaced. Any simple modification, equivalent change and modification of the above examples according to the technical essence of the application are still within the scope of the application.

Claims

1. A compressor preheating control system, characterized in that: The invention comprises a main controller and a compressor inverter connected to each other, wherein the inverter is electrically connected to the motor winding of the compressor; the main controller and the inverter are configured as follows: After receiving the power-on instruction, the main controller generates a preheating instruction according to the real-time ambient temperature and the compressor shutdown time; After receiving the preheating instruction, the frequency converter outputs a low-frequency voltage to the motor winding of the compressor to preheat the compressor.

2. A compressor preheating control system according to claim 1, characterized in that: After receiving the preheating instruction, the frequency converter outputs a sinusoidal wave voltage or an intermittent commutation DC voltage with a frequency of 5-15 Hz to the motor winding.

3. The compressor preheating control system according to claim 1, characterized in that: The compressor is a horizontal compressor, and at least a portion of the motor winding is immersed in the compressor lubricating oil.

4. A preheating method for a compressor preheating control system, characterized in that: The preheating control system includes a main controller and a compressor inverter connected to each other, and the inverter is electrically connected to the motor winding of the compressor; after receiving the power-on instruction, the main controller generates a preheating instruction based on the real-time ambient temperature and the compressor shutdown time and sends it to the inverter; After receiving the preheating instruction, the frequency converter outputs a low-frequency voltage to the motor winding of the compressor to preheat the compressor.

5. The preheating method of a compressor preheating control system according to claim 4, characterized in that: When the outdoor ambient temperature is less than or equal to the first preset temperature, and the compressor shutdown time is greater than or equal to the first preset time or the previous time, the main controller generates a preheating instruction and sends it to the inverter.

6. The preheating method of a compressor preheating control system according to claim 4, characterized in that: The main controller is provided with a correspondence table between ambient temperature and preheating time, and the preheating time is obtained according to the real-time outdoor ambient temperature and the correspondence table, and is sent to the frequency converter.

7. The preheating method of a compressor preheating control system according to claim 6, characterized in that: The corresponding relationship table includes: When the outdoor temperature is 0℃<≤5℃, the preheating time is a minute; When the outdoor ambient temperature is -5℃<≤0℃, the preheating time is b minutes; When the outdoor ambient temperature is -10℃<≤-5℃, the preheating time is c minutes; When the outdoor ambient temperature is -20℃<≤-10℃, the preheating time is d minutes; Among them, a<b<d<d.

8. The preheating method of a compressor preheating control system according to claim 7, characterized in that: The main controller has a built-in timing module, and the main controller controls to stop preheating according to the preheating time recorded by the timing module.

9. The preheating method of a compressor preheating control system according to claim 4, characterized in that: The main controller is further configured to skip preheating and directly send a start instruction to the inverter when the compressor's last operating time exceeds a preset operating time and the shutdown time is less than a first preset time.

10. An air conditioning unit, characterized in that: A compressor preheating control system according to any one of claims 1 to 3 is provided, and a preheating method of the compressor preheating control system according to any one of claims 4 to 9 is executed.

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