Air conditioner

Abstract

The embodiment of the invention discloses an air conditioner which comprises a compressor, an outer fan and a controller, and the controller is configured to judge whether the current operation frequency of the compressor reaches a target frequency forbidding point or not under the condition that the operation frequency of the compressor is adjusted; and under the condition that the current operation frequency of the compressor reaches the target frequency forbidding point, the target frequency modulation rate is determined according to the current operation frequency of the compressor, and the operation frequency of the compressor is adjusted according to the target frequency modulation rate. According to the air conditioner, the operation frequency of the compressor and the rotating speed of the outer fan are jointly adjusted according to the temperatures of the IPM modules of the compressor and the outer fan, so that the service life of equipment is prolonged while the heating or refrigerating performance of the compressor is improved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more particularly to an air conditioner. Background Technology

[0002] In daily life, air conditioners usually increase the operating frequency of the compressor to achieve better cooling or heating effects. As the operating frequency of the compressor increases, the junction temperature of the compressor's IPM module also increases accordingly. To cool the compressor, the speed of the outdoor fan is increased. Consequently, the junction temperature of the outdoor fan's IPM module also increases. Excessive junction temperature of the IPM module will lead to a decrease in the performance and a shortened lifespan of the IPM module.

[0003] In related technologies, the operating frequency of the compressor and the speed of the external fan are often adjusted according to the ambient temperature. However, the junction temperature of the IPM module is not only related to the ambient temperature, but also to the power loss of the power devices. This can lead to the risk of overheating of the IPM module when the compressor operates at too high a frequency.

[0004] Therefore, how to fully utilize the cooling or heating performance of the compressor while avoiding overheating of the compressor and the IPM module of the outdoor fan is an urgent problem to be solved. Summary of the Invention

[0005] This application discloses an air conditioner that obtains the first junction temperature of the compressor IPM module and the second junction temperature of the outdoor fan IPM module, and comprehensively adjusts the operating frequency of the compressor and the speed of the outdoor fan based on the temperature range of the first junction temperature and the second junction temperature. This fully utilizes the heating or cooling performance of the compressor while avoiding overheating of the compressor IPM module and the outdoor fan IPM module.

[0006] This application discloses an air conditioner, which includes:

[0007] A compressor is used to compress the refrigerant circulating in the condenser, expansion valve, and evaporator.

[0008] Outdoor fans are used to regulate outdoor air circulation;

[0009] The controller is used to acquire the first junction temperature of the intelligent power module IPM of the compressor, acquire the second junction temperature of the intelligent power module IPM of the outdoor fan, adjust the operating frequency of the compressor, and adjust the speed of the outdoor fan.

[0010] The controller is configured to:

[0011] The first junction temperature and the second junction temperature are obtained, and the target parameters are adjusted according to the first junction temperature and the second junction temperature. The target parameters include the operating frequency of the compressor and / or the speed of the external fan.

[0012] In the above technical solution, by obtaining the junction temperature of the intelligent power module (IPM) of the compressor and the outdoor fan, and adjusting the frequency of the compressor and the speed of the outdoor fan according to the junction temperature, intelligent control of the air conditioner's working status can be achieved, improving its energy efficiency and stability, avoiding damage caused by overheating, and extending the equipment's lifespan.

[0013] In one possible embodiment, the controller adjusts the target parameters according to the first junction temperature and the second junction temperature, and is configured to:

[0014] Determine the target compressor temperature range where the first junction temperature is located, and the target external fan temperature range where the second junction temperature is located;

[0015] Based on the target compressor temperature range, the target outdoor fan temperature range, and a preset mapping relationship, the operating frequency of the compressor and the speed of the outdoor fan are adjusted. The preset mapping relationship includes multiple preset compressor temperature ranges, multiple preset outdoor fan temperature ranges, and multiple values ​​of the target parameter.

[0016] In the above technical solution, by mapping the junction temperature to the target temperature range and adjusting it in conjunction with the preset mapping relationship, fine control for different temperature ranges is effectively achieved, improving the adaptability of the air conditioner under different environmental conditions and enhancing the intelligence level of the system.

[0017] In one possible embodiment, the plurality of preset compressor temperature ranges include a first compressor temperature range, a second compressor temperature range, a third compressor temperature range, a fourth compressor temperature range, and a fifth compressor temperature range; the plurality of preset outdoor fan temperature ranges include a first outdoor fan temperature range, a second outdoor fan temperature range, a third outdoor fan temperature range, a fourth outdoor fan temperature range, and a fifth outdoor fan temperature range; the controller, based on the target compressor temperature range, the target outdoor fan temperature range, and a preset mapping relationship, adjusts the operating frequency of the compressor and the rotational speed of the outdoor fan, and is configured as follows:

[0018] When the first junction temperature is within the temperature range of the first compressor and the second junction temperature is within the temperature range of the first external fan, the operating frequency of the compressor is increased at a first frequency increase rate and the rotational speed of the external fan is increased at a first acceleration; or,

[0019] When the first junction temperature is within the temperature range of the second compressor and the second junction temperature is within the temperature range of the second external fan, the external fan speed is kept constant, and the operating frequency of the compressor is increased at the second frequency ramp rate; or,

[0020] When the first junction temperature is within the temperature range of the third compressor and the second junction temperature is within the temperature range of the second external fan, the operating frequency of the compressor is maintained constant, and the speed of the external fan is increased by a second acceleration; or,

[0021] When the first junction temperature is within the temperature range of the third compressor and the second junction temperature is within the temperature range of the third external fan, the operating frequency of the compressor and the rotational speed of the external fan are maintained constant; or,

[0022] When the first junction temperature is within the temperature range of the fourth compressor and the second junction temperature is within the temperature range of the fourth external fan, the operating frequency of the compressor is reduced by a first frequency reduction rate and the speed of the external fan is reduced by a third acceleration.

[0023] Wherein, the first up-frequency rate is greater than the second up-frequency rate, and the first acceleration is greater than the second acceleration.

[0024] In the above technical solution, by presetting multiple temperature ranges and adopting different adjustment strategies for different combinations of ranges, the operating status of the compressor and the external fan can be adjusted more flexibly, ensuring that the equipment can operate efficiently under different workloads and further improving the energy-saving effect.

[0025] In one possible embodiment, when the first junction temperature is within the temperature range of the third compressor and the second junction temperature is within the temperature range of the second outdoor fan, after the controller maintains the operating frequency of the compressor unchanged and increases the speed of the outdoor fan with a second acceleration, the controller is further configured to:

[0026] After a first duration, the rate of change of the first junction temperature within the first duration is obtained, and the operating frequency of the compressor and the speed of the external fan are adjusted according to the rate of change of the first junction temperature and the first change threshold.

[0027] If the rate of change of the first junction temperature is less than the first change threshold, the operating frequency of the compressor is increased by the target frequency value;

[0028] If the rate of change of the first junction temperature is greater than or equal to the first change threshold, the rotational speed of the external fan is increased to the target rotational speed value.

[0029] In the above technical solution, a dynamic adjustment mechanism for the operating status of the compressor and outdoor fan is added when the junction temperature of the IPM module changes, which further optimizes the operating efficiency of the equipment. Especially under high load or large temperature changes, it can respond quickly, avoid the temperature from rising or falling too quickly, and improve the stability of the air conditioner.

[0030] In one possible embodiment, the target frequency value is the product of the first duration and the second frequency modulation rate; the target rotational speed value is twice the product of the first duration and the second acceleration.

[0031] In the above technical solution, by clearly defining the calculation method of the target frequency value and the target speed value, a quantitative adjustment method is provided, which makes the control more precise and ensures that the compressor and the outdoor fan can operate at an appropriate rate under different conditions, thereby improving the energy-saving effect and reliability of the air conditioner.

[0032] In one possible embodiment, when the first junction temperature is within the temperature range of the fourth compressor and the second junction temperature is within the temperature range of the fourth outdoor fan, after the controller reduces the operating frequency of the compressor at a first rate of reduction and reduces the speed of the outdoor fan at a third acceleration, the controller is further configured to:

[0033] After the second time period, the rate of change of the first junction temperature during the second time period is obtained, and the operating frequency of the compressor and the speed of the external fan are adjusted according to the rate of change of the first junction temperature and the second change threshold.

[0034] If the rate of change of the first junction temperature is less than the second change threshold, the rotational speed of the external fan is reduced by a fourth acceleration;

[0035] If the rate of change of the first junction temperature is greater than or equal to the first change threshold, the operating frequency of the compressor is reduced at a second rate of reduction.

[0036] Wherein, the fourth acceleration is greater than the third acceleration, and the second frequency reduction rate is greater than the first frequency reduction rate.

[0037] In the above technical solution, by adjusting the rate of change of junction temperature after the second duration, the working status of the compressor and the outdoor fan can be flexibly adjusted according to the actual working conditions, avoiding excessive temperature fluctuations and further improving the stability and energy efficiency of the air conditioner.

[0038] In one possible embodiment, the controller is further configured to:

[0039] When the first junction temperature is within the temperature range of the fifth compressor and the second junction temperature is not within the temperature range of the fifth external fan, the compressor is shut down.

[0040] When the second junction temperature is within the temperature range of the fifth external fan, the compressor and the external fan are shut down.

[0041] In the above technical solution, under extreme temperature conditions, the compressor or external fan can be automatically shut down based on the junction temperature, effectively protecting the equipment, preventing damage caused by excessively high temperatures, and extending the equipment's service life. Simultaneously, the equipment can be restarted under appropriate conditions to ensure it operates within a safe temperature range.

[0042] In one possible embodiment, after the controller shuts down the compressor, the controller is further configured to:

[0043] Obtain the first junction temperature and determine whether the first junction temperature is less than the compressor start-up temperature threshold.

[0044] The compressor is turned on when the first junction temperature is lower than the compressor start-up temperature threshold.

[0045] After the controller shuts down the external fan, the controller is further configured to:

[0046] Obtain the second junction temperature and determine whether the second junction temperature is less than the outdoor fan start-up temperature threshold.

[0047] When the second junction temperature is lower than the outdoor fan start-up temperature threshold, the outdoor fan is turned on.

[0048] Wherein, the compressor start-up temperature threshold is located within the first compressor temperature range, and the outdoor fan start-up temperature threshold is located within the first outdoor fan temperature range.

[0049] In the above technical solution, after the compressor or external fan is turned off, the controller can continue to monitor the junction temperature change and decide when to restart the equipment according to the actual situation, ensuring that the equipment always works within a safe range and avoiding unnecessary losses caused by frequent start-ups and shutdowns.

[0050] In one possible embodiment, the junction temperature of the intelligent power module (IPM) is equal to the sum of the ambient temperature and the temperature rise, wherein the temperature rise is equal to the product of the device power loss and the ambient thermal resistance.

[0051] In the above technical solution, by calculating that the junction temperature of the IPM is equal to the sum of the ambient temperature and the temperature rise, and clarifying the calculation method of the temperature rise, it helps to obtain temperature information under the equipment operating status more accurately, ensure the precision of regulation and control, and further improve the operating stability and energy-saving effect of the equipment.

[0052] In one possible embodiment, the device power loss is determined by the power loss of a single insulated gate bipolar transistor (IGBT) and a fast recovery diode (FRD), wherein the IGBT power loss includes the IGBT's conduction power loss and the IGBT's switching power loss, and the FRD power loss includes the FRD's conduction power loss and the FRD's reverse recovery power loss.

[0053] In the above technical solution, by clarifying the power loss of key power devices such as IGBTs and FRDs, the junction temperature of the IPM can be calculated more accurately, ensuring the safety and efficiency of the equipment under different operating conditions, and reducing the risk of device damage due to excessive power loss.

[0054] Compared to related technologies that adjust the compressor's operating frequency and the outdoor fan's speed solely based on the ambient temperature, the air conditioner provided in this application directly obtains the junction temperature of the compressor's IPM module and the outdoor fan's IPM module. It then adjusts the compressor's operating frequency and the outdoor fan's speed in conjunction with the temperature ranges of these junction temperatures. This fully utilizes the compressor's cooling or heating performance while ensuring that the compressor and outdoor fan's IPM modules operate within their normal temperature ranges, thereby extending the equipment's lifespan. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This application provides a diagram illustrating the application scenario of compressor frequency regulation for an air conditioner.

[0057] Figure 2 This is a schematic diagram of the outdoor unit system architecture of an air conditioner provided in an embodiment of this application;

[0058] Figure 3 A schematic diagram of an IPM module junction temperature calculation method provided in an embodiment of this application;

[0059] Figure 4 A schematic flowchart illustrating a method for coordinated adjustment of a compressor and a fan, provided for an embodiment of this application;

[0060] Figure 5 A schematic flowchart illustrating a method for joint regulation of a compressor and an external fan based on the junction temperature of an IPM module, provided for embodiments of this application;

[0061] Figure 6 A schematic flowchart illustrating an adjustment method for the slow-rise phase of a linkage mechanism, provided for an embodiment of this application;

[0062] Figure 7 A schematic flowchart illustrating a method for adjusting the slow descent phase in conjunction with an embodiment of this application;

[0063] Figure 8 A schematic flowchart illustrating a method for overheating junction protection provided in this application embodiment;

[0064] Figure 9 A schematic block diagram of a control device provided in an embodiment of this application;

[0065] Figure 10 A schematic block diagram of a controller provided in an embodiment of this application. Detailed Implementation

[0066] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0067] To facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. For example, "first instruction" and "second instruction" are used to distinguish different user instructions and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0068] It should be noted that, in this application, the words "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of words such as "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0069] Furthermore, "at least one" refers to one or more, while "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can mean: a, or b, or c, or a and b, or a and c, or b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0070] Furthermore, the terms "comprising" and "having," and any variations thereof, in the embodiments and drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0071] In power devices, the "junction" typically refers to the interface between two regions with different doping types in a semiconductor device. This junction is usually a PN junction or a metal-semiconductor junction. The presence of the junction is crucial to the performance of power devices, affecting their turn-on and turn-off characteristics, breakdown voltage, leakage current, etc. The PN junction is formed by the combination of P-type and N-type semiconductor materials and is the basis of devices such as power diodes and thyristors. When the PN junction is forward biased, current can pass through; when reverse biased, the current is blocked. The metal-semiconductor junction is formed by the contact between a metal and a semiconductor and is used in Schottky diodes. Schottky junctions have low forward voltage drop and fast switching speed, but large reverse leakage current. The insulated gate junction is used in power devices such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs). By controlling the gate voltage, the channel is turned on and off, thereby controlling the current flow.

[0072] Junction temperature (Tj) refers to the temperature of the hottest point inside a semiconductor device (usually the PN junction or other critical junction). For power devices, such as power diodes, MOSFETs, and IGBTs, junction temperature is a critical parameter that directly affects the device's performance, lifespan, and reliability. Junction temperature differs from ambient temperature or the device's casing temperature because power devices generate heat during operation, and there is thermal resistance in transferring heat from the internal chip to the external environment. Therefore, the junction temperature is typically higher than both ambient and casing temperatures. When designing power electronic systems, junction temperature limitations must be considered to ensure that the device operates within its safe operating range. Common heat dissipation designs include heat sinks, fans, and liquid cooling. Junction temperature has a significant impact on device lifespan; the higher the temperature, the more pronounced the accelerated aging effect of the semiconductor device. Therefore, controlling the junction temperature can extend the device's lifespan. Increased junction temperature affects the device's switching speed, on-resistance, and leakage current. High junction temperatures can lead to performance degradation and may even trigger thermal runaway. Many power devices (such as IGBTs and MOSFETs) have junction temperature monitoring and protection mechanisms. When the junction temperature exceeds the designed maximum safe value, the protection circuit will limit power output or directly shut down the device to prevent damage. The parameters affecting the junction temperature of power devices mainly include power consumption, thermal resistance, ambient temperature, heat dissipation method, current density, and operating frequency. Power devices generate heat during operation, primarily from conduction losses (heat generated by resistance during conduction) and switching losses (heat generated by the interaction of current and voltage during switching). Higher power consumption leads to a faster junction temperature rise. Thermal resistance is the resistance to heat transfer from the device's interior to the external environment, typically consisting of two parts: junction-to-case thermal resistance (Rth(jc)) and case-to-ambient thermal resistance (Rth(ca)). Junction-to-case thermal resistance refers to the thermal resistance between the junction and the device's casing, while case-to-ambient thermal resistance refers to the thermal resistance from the device's casing to the environment (heat sink, air, etc.). Lower thermal resistance results in better heat dissipation and a slower junction temperature rise. Ambient temperature directly affects the junction temperature; higher ambient temperatures lead to higher junction temperatures because higher temperatures in the outside air or heat sink reduce the device's heat dissipation efficiency. Heat dissipation methods include, but are not limited to, the heat sink used in the device, air cooling systems, and liquid cooling systems. All these methods affect the junction temperature; more efficient heat dissipation systems can lower the junction temperature. Higher current density generates more heat, so better heat dissipation design is usually required in high-current applications to avoid excessively high junction temperatures. Increasing switching frequency increases switching losses, thereby raising junction temperature. In high-frequency applications, device thermal design is particularly critical. Rising junction temperature leads to increased on-resistance, slower switching speed, increased leakage current, and altered overall performance. In extreme cases, excessively high junction temperatures can trigger thermal runaway, where the heat generated within the device exceeds its heat dissipation capacity, causing the temperature to rise continuously and potentially damaging the device. Prolonged operation at high junction temperatures accelerates the aging of device materials and structure, resulting in a shortened lifespan.Using devices with low thermal resistance can effectively reduce junction temperature; heat dissipation can be accelerated by using heat sinks, air cooling, or liquid cooling; circuit design can be optimized to reduce conduction and switching losses and reduce heat generation; temperature sensors can be used to monitor the junction temperature of devices, and the operating mode can be automatically adjusted or the device can be shut down when the temperature is too high.

[0073] An IPM (Intelligent Power Module) is a power electronic module that integrates power switching devices (such as IGBTs or MOSFETs), drive circuits, and protection circuits. It is primarily used for controlling and converting high-power electrical energy and is commonly found in motor drives, inverters, and renewable energy systems. The intelligent design of IPM modules enables systems to operate more efficiently and safely. An IPM module typically consists of power devices, drive circuits, protection circuits, logic control and signal feedback, and heat dissipation design. The core component of an IPM module is the power switching device, such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). These devices are responsible for switching and converting electrical energy. IGBTs are more suitable for medium-to-high voltage, high-power applications, while MOSFETs are typically used for lower voltage and high-frequency applications. The built-in drive circuit provides the necessary gate or gate drive signals to the power devices. This drive circuit transmits control signals from the microcontroller or digital signal processor to the power devices, ensuring fast and accurate switching. The drive circuit usually also includes isolation functions to ensure safe isolation between the high-voltage and low-voltage sides, preventing high-voltage interference to the control circuit. An IPM module contains... Multiple protection mechanisms ensure that devices are not damaged under abnormal conditions. Common protection functions include, but are not limited to, overcurrent protection, overtemperature protection, undervoltage protection, and short-circuit protection. IPM modules typically have a logic control interface that can receive external control signals (such as PWM signals) to control the switching of power devices. Simultaneously, the module provides feedback signals (such as overheat and overcurrent status) to the main control system for real-time monitoring and adjustment of operating status. Since power devices generate a significant amount of heat during operation, IPM modules usually integrate heat sinks or have a dedicated thermal management system. The junction temperature inside the module is typically monitored by a built-in thermistor to ensure the module operates within a safe temperature range. The working principle of an IPM module is to control the switching of internal power devices to drive motors or achieve power conversion. The internal drive circuit of the IPM module converts low-power control signals into high-voltage or high-current signals to control the switching state of power devices (such as IGBTs or MOSFETs), thereby achieving high-power output. The protection circuit in the module monitors the current, temperature, voltage, and other parameters of the power devices in real time. Once an abnormality (such as overcurrent or overtemperature) is detected, the protection circuit will quickly activate, shutting down the power devices to prevent damage. IPM modules are widely used in applications requiring efficient power conversion and precise control, especially in high-power motor drive systems and inverters, including but not limited to motor drives, inverters, home appliances, electric vehicles, and industrial automation. IPM modules also offer advantages such as integrated design, high efficiency, high reliability, simplified design, and good electromagnetic compatibility.

[0074] In related technologies, the operating frequency of the air conditioner compressor and the speed of the outdoor fan are often adjusted according to the ambient temperature. However, the junction temperature of the air conditioner's IPM module is affected by a variety of factors. If the compressor frequency and fan speed are adjusted only based on the ambient temperature, the IPM module junction temperature may become too high. This is especially true when the compressor load is high, the ambient temperature is low, but the heat dissipation is poor. The heat generated inside the module may not be dissipated in time, leading to overheating. This may cause a decline in the performance of power devices, or even thermal runaway, shortening the module's lifespan, or directly causing equipment failure. Even at low ambient temperatures, the IPM module junction temperature may still be too high if the compressor load is too high. Ignoring the IPM module junction temperature means that the system may operate at high power for longer periods, especially when high compressor frequency or fan speed is not required. When the ambient temperature is low but the compressor is running at high frequency, the outdoor fan may not provide sufficient heat dissipation, resulting in inadequate heat dissipation of the IPM module. Conversely, at higher ambient temperatures, the fan may overwork, increasing energy consumption.

[0075] This application embodiment acquires the junction temperature of the compressor IPM module and the outdoor fan IPM module in real time through a controller. By selecting appropriate adjustment strategies based on the temperature range of the compressor IPM module junction temperature and the outdoor fan IPM module temperature, the operating frequency of the compressor and the speed of the outdoor fan are linked. Compared with related technologies that only adjust the operating frequency of the compressor and the speed of the outdoor fan based on the ambient temperature, this application embodiment fully considers the junction temperature of the air conditioner power device IPM module. While giving full play to the cooling or heating performance of the compressor, it avoids the junction temperature of the IPM module being too high, thus extending the service life of the equipment.

[0076] In order to realize the air conditioner as described above, the application scenario of the air conditioner according to the embodiments of this application will be introduced first, so as to fully understand the working principle of each component of the outdoor unit of the air conditioner.

[0077] like Figure 1 The figure shown is a compressor frequency adjustment application scenario diagram 100 provided in the embodiment of this application. The application scenario may include compressor 101, condenser 102 and outdoor fan 103.

[0078] In some possible embodiments, the main function of compressor 101 is to compress and propel the refrigerant in the air conditioning system to achieve cooling and heating effects. Compressor 101 can be a reciprocating compressor, rotary compressor, scroll compressor, screw compressor, or centrifugal compressor; this application does not specifically limit the types. The refrigerant compressed by compressor 101 can include, but is not limited to, Freon refrigerants such as dichlorodifluoromethane (CFC-12) and dichlorofluoromethane (HCFC-22); hydrofluorocarbon refrigerants such as tetrafluoroethane (HFC-134a), R410A, and difluoromethane (R32); natural refrigerants such as propane (R290), isobutane (R600a), and carbon dioxide (R744); and mixed refrigerants with low Global Warming Potential (GWP) such as R407C, R446A, and R447A. The components of compressor 101 may include, but are not limited to, an electric motor, compressor cylinder, piston or blades, scroll or helical rotor, intake valve and exhaust valve, oil pump and lubrication system, condenser connecting pipes, housing and sound insulation system, and starting capacitor. Taking the cooling mode of an air conditioner as an example, the working process of the compressor 101 can be divided into the suction stage, compression stage, discharge stage, and condensation and throttling stage. In the suction stage, the compressor 101 draws in low-pressure, low-temperature refrigerant gas from the evaporator. At this time, the refrigerant has absorbed heat from the room and is in a low-pressure, low-temperature gaseous state. In the compressor stage, the compressor 101, driven by the electric motor, compresses the low-pressure, low-temperature refrigerant gas into a high-pressure, high-temperature gas. At this time, the pressure and temperature of the gas increase significantly. In the discharge stage, the high-pressure, high-temperature refrigerant is transported by the compressor 101 to the condenser 102. In the condenser 102, the refrigerant releases heat and cools down, turning into a high-pressure liquid. In the condensation and throttling stage, the high-pressure liquid refrigerant enters the evaporator after being depressurized by the throttling valve, becoming a low-pressure, low-temperature liquid and evaporating into a gas. At the same time, it absorbs heat from the room. The above process will continue to cycle, ultimately achieving the goal of discharging heat from the room to the outside and achieving the cooling effect. In the heating mode, the air conditioner uses devices such as a four-way valve to regulate the flow of refrigerant, achieving the opposite heat transfer process. The compressor 101 is the core component of the air conditioning system. It completes the heat transfer of the entire air conditioning system by changing the pressure and state of the refrigerant.

[0079] In some possible embodiments, the primary function of the outdoor unit condenser 102 is to cool and condense the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 101 into liquid refrigerant. This is one of the key steps in the air conditioning refrigeration cycle, involving the release and transfer of heat. The type of condenser 102 may include, but is not limited to, air-cooled condensers, water-cooled condensers, evaporative cooling condensers, microchannel condensers, and finned tube condensers. The components of the condenser 102 may include, but are not limited to, heat exchange tubes, heat dissipation fins, a water flow system (suitable for water-cooled and evaporative condensers), a housing or frame, a spray device (only applicable to evaporative cooling condensers), a liquid collector, a liquid outlet and an air inlet, a pressure controller and sensors, and a drainage system. In the cooling mode of the air conditioner, high-temperature gaseous refrigerant enters the heat exchange tubes of the condenser 102 and begins to exchange heat with the cooling medium (air or water) outside the condenser 102. In an air-cooled condenser, air is used as the cooling medium; a fan pushes air through the condenser fins, absorbing the heat released in the refrigerant pipes and carrying it away. In a water-cooled condenser, water is used as the cooling medium; water flows over the surface of the condenser pipes, absorbing the heat released by the refrigerant, and then the heated water is cooled and recycled through a cooling water system (such as a cooling tower). As the heat of the refrigerant is continuously carried away by the external medium, the temperature of the refrigerant gradually decreases. With further heat transfer, the refrigerant gradually changes from a gaseous state to a liquid state. This process is called "condensation." This phase change releases a large amount of latent heat (condensation latent heat), which is the main heat release process in condenser 102. After the refrigerant is completely condensed into a liquid state, it is collected in the liquid collector at the bottom of the condenser. Then, the condensed liquid refrigerant is discharged from the condenser through the outlet and enters the next cycle stage, that is, after being depressurized by the expansion valve, it enters the evaporator and begins a new round of refrigeration cycle.In the heating mode of the air conditioner, the function of the condenser 102 is the opposite of that in the cooling mode. In this mode, the condenser 102 no longer acts as a heat releaser but instead absorbs heat, while the evaporator releases heat. The compressor 101 still compresses the low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant. However, through the switching of the four-way valve, this high-temperature, high-pressure gas is sent to the evaporator in the indoor unit. The evaporator then acts as a condenser, releasing heat into the room. The condenser 102 in the outdoor unit becomes the evaporator for the refrigerant, absorbing heat from the outside air. When the refrigerant flows back from the indoor unit to the outdoor unit, it has become a low-temperature liquid. The condenser 102 of the outdoor unit (which acts as an evaporator at this time) absorbs heat from the surrounding air, causing the refrigerant to evaporate from a liquid state to a gaseous state. As the refrigerant absorbs heat and vaporizes, the condenser 102 obtains heat from the external environment and transfers this heat to the refrigerant, causing it to become gaseous. When the refrigerant absorbs enough heat in the outdoor unit, it enters the gaseous state and is drawn into the compressor 101. The compressor compresses the gaseous refrigerant into a high-temperature, high-pressure gas. After switching through the four-way valve, the high-temperature, high-pressure gaseous refrigerant is sent to the indoor unit, where it condenses in the evaporator (which acts as a condenser at this time), releasing a large amount of heat and thus heating the indoor air.

[0080] In some possible embodiments, the outdoor fan 103 can be an AC motor fan or a DC motor fan; this application does not specifically limit the embodiments. The structural components of the outdoor fan 103 may include, but are not limited to, a motor, fan blades, grille or shroud, fan bracket, fan controller, electrical connectors and wiring harnesses, and vibration damping devices. The main function of the outdoor fan 103 is to help the condenser 102 dissipate heat by pushing airflow over it, thus maintaining the efficient operation of the air conditioning system. In the cooling mode of the air conditioner, the compressor 101 transfers the heat absorbed indoors to the condenser 102 via refrigerant. The outdoor fan 103 helps the condenser 102 expel this heat outdoors by forcing airflow. Through heat dissipation, the outdoor fan 103 helps lower the temperature of the condenser 102, thereby maintaining the normal pressure of the air conditioning system. If the condenser 102 cannot dissipate heat effectively, the system pressure will increase, potentially causing the compressor 101 to overload, the cooling effect to deteriorate, or even triggering a system shutdown for protection. The working efficiency of the outdoor fan 103 directly affects the energy efficiency of the entire air conditioning system. Good heat dissipation can reduce the energy consumption of the system and improve the energy efficiency ratio of the air conditioner. In inverter air conditioners, the speed of the outdoor fan 103 can be adjusted according to actual needs to further optimize energy consumption.

[0081] The above introduction to the application scenarios of air conditioners facilitates understanding of their operating modes and cooling / heating principles, providing a theoretical foundation for further understanding the air conditioner control method provided in the embodiments of this application. Next, the system architecture of the air conditioner's outdoor unit will be further described to fully understand how the various hardware components of the outdoor unit work together to achieve the air conditioner control method provided in the embodiments of this application.

[0082] like Figure 2 The diagram shown is a schematic diagram 200 of the outdoor unit system architecture of an air conditioner provided in an embodiment of this application. The system architecture of the outdoor unit may include, but is not limited to, components such as a controller 201, a memory 202, a compressor 203, an outdoor fan 204, a condenser 205, and an outdoor unit housing 206. The system architecture of the outdoor unit may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0083] The controller 201 is the control center of the air conditioner. It connects various parts of the air conditioner via various interfaces and lines. By running or executing software programs and / or modules stored in the memory 202, and by calling data stored in the memory 202, it performs various functions and processes data, thereby providing overall monitoring of the air conditioner. Optionally, the controller 201 may include one or more processing units; preferably, the controller 201 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and applications, and the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into the controller 201.

[0084] The memory 202 can be used to store software programs and modules. The controller 201 executes various functions and data processing of the air conditioner by running the software programs and modules stored in the memory 202. The memory 202 may mainly include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function (such as junction temperature detection function, frequency control function, speed control function, etc.). The data storage area may store data created based on the use of the air conditioner (such as temperature threshold, frequency adjustment rate, acceleration, etc.). In addition, the memory 202 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0085] The compressor 203 typically consists of a casing, motor, compression chamber, intake and exhaust valves, and lubrication system. The primary function of the compressor 203 is to compress low-temperature, low-pressure gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant. During the compression process, the refrigerant's pressure and temperature increase significantly. The controller 201 adjusts the frequency of the compressor 203 using variable frequency technology, thereby controlling the air conditioner's cooling capacity.

[0086] In some possible embodiments, the controller 201 can calculate the required operating frequency of the compressor 203 according to a preset algorithm. The controller 201 then generates a PWM (Pulse Width Modulation) signal based on the calculation result and transmits it to the frequency converter. The frequency converter is the core component of the motor control system, adjusting the compressor motor speed by changing the frequency and voltage of the power supply. The duty cycle (the ratio of the "high" to "low" levels of the pulse signal) of the PWM signal is proportional to the target frequency. After receiving the PWM signal, the frequency converter controls the frequency and voltage of the three-phase AC power output to supply the compressor 203 motor. When the frequency of the AC power supplied to the motor increases, the compressor 203 motor speed increases, thereby increasing the operating frequency of the compressor 203; conversely, decreasing the frequency slows down the compressor 203 speed. In this way, the controller 201 can accurately control the output capacity of the air conditioning system, enabling the indoor temperature to quickly reach and remain at the set value.

[0087] The outdoor fan 204 typically consists of components such as fan blades, a motor, a motor bracket, a fan cover, a junction box, and a control circuit. The core function of the outdoor fan 204 is to remove heat from the condenser 205 through airflow. When the high-temperature, high-pressure refrigerant passes through the condenser 205, it releases heat and gradually cools into a liquid state. The outdoor fan 204, by rotating, pushes air through the fins of the condenser 205, transferring the released heat to the outdoor air, thereby maintaining the decrease in refrigerant temperature.

[0088] In some possible embodiments, the controller 201 calculates the required rotational speed of the outdoor fan 204 based on the current operating conditions (such as condenser temperature, system pressure, etc.), and then generates a corresponding PWM control signal. The frequency of the control signal is usually fixed (e.g., above 20kHz to avoid audible noise during motor operation), while the duty cycle is changed. If the outdoor fan 204 needs to operate at high speed, the controller 201 increases the duty cycle of the PWM signal, increasing the "on" time, resulting in the motor receiving a higher average voltage and increasing the speed. If it is necessary to reduce the speed of the outdoor fan 204, the controller 201 reduces the duty cycle of the PWM signal, causing the motor to receive a lower average voltage and slowing down the speed. The duty cycle adjustment is very flexible and can be quickly fine-tuned according to changes in the external environment. Due to the design characteristics of DC motors (especially brushless DC motors), they can quickly respond to changes in the PWM signal. As the duty cycle of the PWM signal is adjusted, the motor speed also changes synchronously, enabling precise control of the fan speed.

[0089] The condenser 205 consists of a piping system, fins, a support frame, and a housing. The main function of the condenser 205 is to cool the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 203, releasing heat and converting it into a high-pressure liquid refrigerant. As the refrigerant passes through the condenser 205, it exchanges heat with the air flowing through its fins, transferring heat from the refrigerant to the air, causing the refrigerant to condense from a gaseous state to a liquid state. If the condenser 205's heat dissipation is ineffective, the refrigerant cannot condense efficiently, the system pressure will be too high, leading to compressor 203 overload or even damage.

[0090] By introducing the system architecture and other hardware aspects of the air conditioner's outdoor unit, you can understand the functions of each component. Building on this foundation, we will further explain the junction temperature calculation method for the IPM module.

[0091] like Figure 3 The diagram shown is a schematic diagram 300 of an IPM module junction temperature calculation method provided in an embodiment of this application.

[0092] In some possible embodiments, the controller 301 is electrically connected to the temperature sensor 305, the compressor IPM module 307, the outdoor fan IPM module 309, and the memory 310. The controller 301 can receive the Ta parameter 302 from the temperature sensor 305 and the V parameter from the compressor IPM module 309. CE I C , τ, V F Parameter 303, memory 310 f SW E SW(on) E SW(off) E RFD(off)Parameters 304 and controller 301 can calculate the junction temperature of compressor IPM module 307 and outdoor fan IPM module 309 respectively based on parameters 302, 303 and 304.

[0093] In some possible embodiments, the compressor IPM module 307 is integrated into the compressor 306. The compressor IPM module 307 integrates power switching devices such as IGBTs and RFDs, drive circuits, protection circuits, and other intelligent control functions. The power devices such as IGBTs and RFDs are used to control the current and voltage of the compressor. These power devices are responsible for driving the operation of the compressor and adjusting the operating speed of the compressor through the switching frequency, thereby realizing the cooling or heating function of the air conditioner.

[0094] In some possible embodiments, the external fan IPM module 309 is integrated into the external fan 308. The external fan IPM module 309 integrates power switching devices such as IGBTs and RFDs, which can quickly switch according to the input control signal to adjust the motor voltage and current of the external fan 308.

[0095] In some possible embodiments, the main parameters affecting the junction temperature of the compressor IPM module 307 or the outdoor fan IPM module 309 are the power consumption, thermal resistance, and ambient temperature of the power devices. The junction temperature of the compressor IPM module 307 or the outdoor fan IPM module 309 can be calculated using the junction temperature calculation formula:

[0096] T j =T a +P loss *R th(j-c) (1)

[0097] Among them, T a For ambient temperature, P loss R is the total loss of IPM. th(j-c) This refers to the thermal resistance of the IPM module junction to the environment.

[0098] Since IPM modules typically use a three-phase inverter structure, each phase requires two switches. Each switch usually contains an Insulated Gate Bipolar Transistor (IGBT) and a Fast Recovery Diode (FRD) connected in parallel. Each phase requires two IGBTs (upper and lower arms), so a total of six IGBTs are needed (3 phases × 2 IGBTs / phase). Each IGBT is connected in parallel with an FRD to handle reverse current, therefore six FRDs are required. The total losses of an IPM module can be obtained using the following formula:

[0099] P loss =6*(P ss(IGBT) +P ss(FRD) (2)

[0100] Where P ss(IGBT) P represents the total loss of the IGBT. ss(FRD) This represents the total loss of the FRD.

[0101] The total loss of IGBT is calculated using the following formula:

[0102] P ss(IGBT) =P cd +P sw (3)

[0103] Among them, P cd For the conduction loss of the IGBT, P sw This refers to the switching losses of the IGBT.

[0104] The total loss of the FRD is calculated using the following formula:

[0105] P ss(FRD) =P Fcd +P rr (4)

[0106] Among them, P ss(FRD) For the conduction loss of the FRD, P rr The turn-off loss of the FRD is P. rr This includes the reverse recovery loss of the FRD.

[0107] When the current is sinusoidal, a single IGBT module is only responsible for the positive half-cycle (or negative half-cycle) current flow, so the conduction loss of a single IGBT is:

[0108]

[0109] Among them, V CE I is the terminal voltage of the IGBT. C Let V be the current flowing through the IGBT from the IPM, and τ be the duty cycle. CE with I C The relationship between them can be approximated by a straight line, as follows:

[0110] V CE =V CE0 +r CE *I C (t) (6)

[0111] Among them, V CE0 For the threshold voltage, r CE The equivalent resistance for IGBT conduction can be determined using the V value provided in the product datasheet. CE with I C The curve between them is obtained.

[0112] When an IPM module uses bipolar sinusoidal modulation, the carrier signal is typically a triangular or sawtooth wave. Both the positive and negative components (polarity) of the modulation waveform affect the output waveform. The carrier waveform can change upwards or downwards, thus the output voltage switches between positive and negative. For example, when the modulating wave is stronger than the carrier wave, the output is a positive voltage; when the modulating wave is weaker than the carrier wave, the output is a negative voltage. In this case, the duty cycle τ of the signal is:

[0113]

[0114] Where M is the modulation ratio, φ is the phase difference between the IGBT voltage and current, and ω is the angular frequency.

[0115] Let the time-domain expression of the current be:

[0116] I C (t)=I CP sin(ωt) (8)

[0117] Among them, I CP This represents the peak current.

[0118] The field-of-view expression for voltage is then:

[0119] V CE (t)=V P sin(ωt+φ) (9)

[0120] Among them, V P This represents the peak voltage.

[0121] Substituting equations (6), (7), (8), and (9) into equation (1) in turn, we get:

[0122]

[0123] The switching loss of a single IGBT within half a cycle is:

[0124]

[0125] Among them, f SW E is the switching frequency. SW(on) The energy lost during the IGBT's initial operation, E SW(off) To shut down the energy lost in one operation.

[0126] E SW(on) and E SW(off) With current I C The variation of E is non-linear and difficult to describe accurately quantitatively using analytical expressions. Product specifications will provide rated current and rated voltage, or E under a few modes. SW(on) and E SW(off) The curve, as shown by experiments, indicates that E SW(on) and ESW(off) Linearization can meet the requirements of engineering calculations, that is:

[0127]

[0128] Among them, E SW(on)p Rated current I CN and rated voltage V CEN The energy lost when the IGBT is turned on once, E SW(off)p Rated current I CN and rated voltage V CEN The energy lost when the IGBT is turned off once, V dc I is the voltage of the DC bus. CN For the rated operating current, V CEN This is the rated operating voltage.

[0129] For the conduction loss of the FRD, we have:

[0130]

[0131] Among them, V F This is the terminal voltage across FRD.

[0132] Based on the above analysis, the derivation method of the formula for calculating the conduction loss of IGBTs is consistent, and we have:

[0133]

[0134] Among them, V F0 r is the threshold voltage of the FRD. F The equivalent resistance of the FRD in the on-state can be determined by the V specified in the product datasheet. F with I C The curve was obtained.

[0135] The turn-on loss of the FRD is negligible; only its turn-off loss is calculated. The turn-off loss is:

[0136]

[0137] Among them, E FRD(off) For the energy lost when the FRD is turned off once, equation (15) can be approximated as:

[0138]

[0139] Among them, E rec(ICN) For the rated current I CN and rated voltage V CEN The energy lost during reverse recovery when RFD is turned off.

[0140] For example, let the modulation ratio M = 0.866, and φ be the phase difference between the current flowing through the IGBT or FRD and the terminal voltage. Ideally, the two are 180° apart. In actual operation, due to the presence of conduction delay and parasitic parameters, there may be a positive or negative deviation of several angles. In the calculation process, φ can be taken as...

[0141] =180°, then cosφ=1, take r CE =0.0025Ω, V CE0 =1.75V, I CP =265A, substituting the above parameters into equation (10) yields P. cd =161.9W. Take E. SW(on)p =26mJ, E SW(off)p =55.5mJ, V dc =645V, I CN =450A, V CEN =600V, substituting the above parameters into equation (12) gives P sw =32.86W. Take V. F0 =1.65V, r F =0.0013Ω, substituting the above parameters into equation (14) yields P Fcd =25.3W. Take E. rec(ICN) =48.5mJ, substituting the above parameters into equation (16) yields P rr =135.4W. In summary, the loss P of a single IGBT is... ss(IGBT) =194.76W, single FRD loss P ss(FRD) =160.7W, then the total loss P loss =2132.76W, taking the ambient temperature Ta=40℃, thermal resistance R th(j-c) =0.05℃ / W, then the junction temperature T of the IPM module is... j =146.64℃.

[0142] The above embodiments accurately calculate the junction temperature of the compressor and the outdoor fan IPM module by combining data acquired from multiple sensors. This junction temperature calculation method ensures that the temperature of the power devices remains within a safe range, thereby improving the safety and reliability of the equipment. The following section introduces a method for coordinated regulation of the compressor and fan.

[0143] like Figure 4 The diagram shown is a schematic flowchart 400 illustrating a method for coordinated adjustment of a compressor and a fan according to an embodiment of this application. The method includes the following steps:

[0144] S401, obtain the first junction temperature and the second junction temperature.

[0145] In some possible embodiments, a voltage sensor is installed between the collector and emitter of the IGBT or RFD in the IPM module. The high voltage is converted into a low voltage signal acceptable to the controller through a voltage divider circuit or an electrical isolation circuit (such as an optocoupler or a Hall effect sensor). This signal is then converted into a digital signal by an analog-to-digital converter (ADC) for the microcontroller to read. The Hall effect current sensor can measure the current in the conductor non-contactly, accurately measure high currents, and provide good electrical isolation. A low-impedance shunt resistor is connected in series with the emitter of the IGBT or RFD. The current is indirectly calculated by measuring the voltage drop across the resistor. The current measurement signal is usually an analog signal. After conversion by the ADC, the controller can obtain the real-time current value of the IGBT or RFD. The drive signal of the IGBT or RFD is directly generated by the controller, so the duty cycle can be obtained by reading the PWM setpoint.

[0146] In some possible embodiments, the temperature sensor is installed on the outdoor unit of the air conditioner. The resistance of the thermistor of the temperature sensor changes with temperature. The resistance value can be converted into a voltage signal through a simple circuit. The controller measures the voltage signal and then calculates the actual ambient temperature by looking up a table or formula.

[0147] In some possible embodiments, the air conditioner also includes a memory that stores the switching frequency of the IGBT or RFD of the IPM module, the energy loss of the IGBT once turned on, the energy loss of the IGBT once turned off, and the energy loss of the RTD once reverse recovery.

[0148] In some possible embodiments, the controller acquires relevant parameters transmitted from the temperature sensor, the compressor IPM module, the outdoor fan IPM module, and the memory, and calculates the first junction temperature of the compressor IPM module and the second junction temperature of the outdoor fan IPM module in real time according to the junction temperature calculation formula.

[0149] S402, adjust the target parameters according to the first junction temperature and the second junction temperature, wherein the target parameters include the operating frequency of the compressor and / or the rotational speed of the external fan.

[0150] In some possible embodiments, the controller will detect in real time the different temperature ranges of the first junction temperature and the different temperature ranges of the second junction temperature, and adopt different linkage adjustment strategies for the compressor and the controller. When both the first and second junction temperatures are low, the compressor's operating frequency and the outdoor fan's speed can be rapidly increased to quickly improve the compressor's cooling or heating performance. When the first and second junction temperatures begin to rise, the compressor's frequency increase rate and the outdoor fan's acceleration can be reduced, while the compressor's operating frequency and the outdoor fan's speed are further increased to the compressor's maximum junction temperature boundary to improve system performance. When the first and second junction temperatures reach near the system's preset maximum junction temperature boundary, the compressor's operating frequency and the outdoor fan's speed are kept constant to limit the junction temperature of the compressor's IPM module and the outdoor fan's IPM module from rising further. When the first and second junction temperatures exceed the system's preset maximum junction temperature boundary, the controller controls the compressor to reduce its operating frequency and the outdoor fan to reduce its speed to lower the junction temperature of the compressor's IPM module and the outdoor fan's IPM module. When the first and second junction temperatures exceed the system's preset maximum junction temperature boundary by a certain value, the controller stops outputting PWM signals and shuts down the compressor and outdoor fan to allow them to cool down rapidly.

[0151] The above embodiments effectively improve the energy efficiency of air conditioners by controlling the coordinated adjustment of the compressor's operating frequency and the fan speed, while protecting the equipment from overheating. This method can flexibly adjust the operating status of the compressor and fan under different junction temperature conditions, further optimizing the performance of the air conditioner. The following section further describes how to adjust the target parameters specifically according to the temperature range of the junction temperature.

[0152] like Figure 5 The diagram shown is a schematic flowchart 500 illustrating a method for joint regulation of a compressor and an external fan based on the junction temperature of an IPM module, according to an embodiment of this application. The method includes the following steps:

[0153] S501, the controller obtains the first junction temperature of the compressor IPM module and the second junction temperature of the outdoor fan IPM module.

[0154] Step S501 is similar to step S401, and will not be described again here.

[0155] S502, the controller determines the temperature range of the first junction temperature and the temperature range of the second junction temperature.

[0156] In some possible embodiments, five compressor temperature thresholds, T0, T1, T2, T3, T4 with T0 < T1 < T2 < T3 < T4, and five external fan temperature thresholds, Ta, Tb, Tc, Td, Te with Ta < Tb < Tc < Td < Te, are stored in the memory of the air conditioner. The four compressor temperature thresholds T1, T2, T3, T4 divide the junction temperature of the compressor IPM module into the first compressor temperature range, the second compressor temperature range, the third compressor temperature range, the fourth compressor temperature range, and the fifth compressor temperature range. There is also a compressor temperature threshold T0 in the first compressor temperature range. When the compressor is shut down due to overheating of the first junction temperature, the compressor can only be started when the first junction temperature is less than T0. The four external fan temperature thresholds Tb, Tc, Td, Te divide the junction temperature of the external fan IPM module into the first external fan temperature range, the second external fan temperature range, the third external fan temperature range, the fourth external fan temperature range, and the fifth external fan temperature range. There is also an external fan temperature threshold Ta in the first external fan temperature range. When the external fan is shut down due to overheating of the second junction temperature, the external fan can only be started when the second junction temperature is less than Ta.

[0157] S503, the controller obtains the adjustment parameter according to the temperature ranges where the first junction temperature and the second junction temperature are located and the mapping relationship between the temperature ranges and the adjustment strategy.

[0158] In some possible embodiments, each target compressor temperature range where the first junction temperature is located and each target external fan temperature range where the second junction temperature is located correspond to a linkage adjustment strategy for the compressor and the external fan. The mapping relationship between the target compressor temperature range, the target external fan temperature range, and the adjustment strategy is stored in the memory, as shown in Table 1:

[0159] Table 1

[0160]

[0161] S504, the controller adjusts the compressor frequency and the rotational speed of the external fan using the adjustment parameter.

[0162] In some possible embodiments, when the first junction temperature is in the first compressor temperature range (0, T1) and the second junction temperature is in the first external fan temperature range (0, Tb), at this time, the compressor and the external fan are in the rapid increase stage of rotational speed and frequency. The compressor is controlled to rapidly increase its operating frequency at the first frequency increase rate v1, and the external fan is controlled to rapidly increase its rotational speed at the first acceleration a1.

[0163] In some possible embodiments, when the first junction temperature is located in the second compressor temperature range [T1, T2) and the second junction temperature is located in the second outdoor fan temperature range [Tb, Tc), the compressor and the outdoor fan are in the frequency ramp-up phase. The controller increases the operating frequency of the compressor at a second ramp-up rate v2 and keeps the speed of the outdoor fan constant, wherein the second ramp-up rate v2 is less than the first ramp-up rate v1.

[0164] In some possible embodiments, when the first junction temperature is located in the third compressor temperature range [T2,T3) and the second junction temperature is located in the second outdoor fan temperature range [Tb,Tc), the compressor and the outdoor fan are in the frequency ramp-up phase. The controller maintains the compressor's operating frequency unchanged and increases the outdoor fan speed with a second acceleration within a preset time Δt1, wherein the second acceleration is less than the first acceleration.

[0165] In some possible embodiments, when the first junction temperature is located in the third compressor temperature range [T2, T3) and the second junction temperature is located in the third outdoor fan temperature range [Tc, Td), the compressor and the outdoor fan are in the restricted-up phase, and the controller maintains the compressor's operating frequency and the outdoor fan's speed unchanged.

[0166] In some possible embodiments, when the first junction temperature is located in the fourth compressor temperature range [T3,T4) and the second junction temperature is located in the fourth outdoor fan temperature range [Td,Te), the compressor and the outdoor fan are in a slow reduction phase. The controller reduces the operating frequency of the compressor at a first reduction rate v3 and reduces the speed of the outdoor fan at a third acceleration a3 within a preset time Δt2.

[0167] In some possible embodiments, when the first junction temperature is located in the fifth compressor temperature range [T4,∞) and the second junction temperature is located in the fifth outdoor fan temperature range [Te,∞), the compressor and the outdoor fan are in the junction temperature too high shutdown protection, and the controller stops the PWM signal output of the compressor IPM module and the PWM signal output of the outdoor fan IPM module.

[0168] In some possible embodiments, if the target compressor temperature range where the first junction temperature is located and the target outdoor fan temperature range where the second junction temperature is located are not as described above, the compressor frequency and the outdoor fan speed are adjusted according to the strategy shown in Table 1.

[0169] For example, when the air conditioner starts, the controller powers on the compressor and outdoor fan. The first junction temperature of the compressor IPM module and the second junction temperature of the outdoor fan IPM module are both ambient temperature (25°C). Five compressor temperature ranges are defined as (0°C, 30°C), [30°C, 60°C), [60°C, 90°C), [90°C, 120°C), and [120°C, ∞). Five outdoor fan temperature ranges are defined as (0°C, 32°C), [32°C, 64°C), [64°C, 96°C), [96°C, 128°C), and [128°C, ∞). At this time, the controller increases the compressor's operating frequency at a first frequency ramp rate of 10Hz / s and an acceleration of 15r / s. 2 The outdoor fan speed is increased until the first junction temperature rises to 30°C and the second junction temperature rises to 34°C. Then, the controller increases the compressor's operating frequency at a second boost rate of 5Hz / s while maintaining the outdoor fan speed constant. After a period of time, the first junction temperature rapidly rises to 60°C and the second junction temperature rises to 58°C. The controller then maintains the compressor's operating frequency constant and increases the compressor's operating frequency at a second acceleration of 10r / s. 2 The outdoor fan speed is increased by 10 rpm for 10 seconds. After a period of time, the first junction temperature rises to 78°C, and the second junction temperature rises to 70°C. At this time, the controller maintains the compressor operating frequency and the outdoor fan speed unchanged. After a period of time, the first junction temperature continues to rise to 90°C, and the second junction temperature rises to 100°C. At this time, the compressor reduces its operating frequency at a first reduction rate of 15 Hz / s for 20 seconds, and then accelerates at a third rate of 20 rpm. 2 After reducing the speed of the outdoor fan for 20 seconds, the first junction temperature rises to 120℃ and the second junction temperature rises to 130℃. At this time, the controller detects that the junction temperature of the compressor and the junction temperature of the outdoor fan are too high, and stops the PWM signal output of the compressor IPM module and the outdoor fan IPM module, so that the operating frequency of the compressor drops rapidly and the speed of the outdoor fan drops rapidly.

[0170] The above embodiments, by adjusting the compressor and outdoor fan according to the junction temperature of the IPM module, can ensure cooling / heating performance while preventing module overheating and extending the service life of the equipment. The following sections will further describe the linked slow-rise stage, linked slow-fall stage, and over-temperature protection stage in the above embodiments.

[0171] like Figure 6 The diagram shown is a schematic flowchart 600 illustrating an adjustment method for a slow-rise phase in linkage according to an embodiment of this application. The method includes the following steps:

[0172] S601, the controller maintains the compressor's operating frequency unchanged during the first duration, and increases the speed of the external fan with a second acceleration.

[0173] In some possible embodiments, when the first junction temperature of the compressor IPM module is in the third compressor temperature range and the second junction temperature of the outdoor fan IPM module is in the second compressor temperature range, the controller controls the compressor to maintain its current operating frequency and increases the speed of the outdoor fan with a second acceleration within a first duration.

[0174] S602, the controller acquires the rate of change of the first junction temperature over a first time period.

[0175] In some possible embodiments, the controller increases the speed of the external fan during a first duration and detects the rate of change of the first junction temperature of the compressor IPM module during the first duration, the rate of change being the difference between the final value and the initial value of the first junction temperature.

[0176] S603, the controller determines whether the rate of change is less than the first change threshold.

[0177] In some possible embodiments, if the rate of change of the first junction temperature is less than the first change threshold, it indicates that the junction temperature of the compressor IPM module has increased less or decreased, and the operating frequency of the compressor can be increased; if the change of the first junction temperature is greater than or equal to the first change threshold, it indicates that the junction temperature of the compressor IPM module has increased more, and the speed of the external fan should be increased to dissipate heat from the compressor IPM module.

[0178] S604, the controller increases the compressor's operating frequency by the target frequency value.

[0179] In some possible embodiments, when the rate of change of the first junction temperature is less than the first change threshold, the controller controls the compressor to increase the operating frequency to the target frequency value, that is, the controller increases the operating frequency of the compressor at a second frequency increase rate within a first duration.

[0180] S605, the controller increases the speed of the external fan by the target speed value.

[0181] In some possible embodiments, if the change in the first junction temperature is greater than or equal to the first change threshold, the controller controls the operating frequency of the compressor to increase the target speed value, that is, the controller increases the speed of the outdoor fan with a second acceleration for twice the first duration or increases the speed of the outdoor fan with a second acceleration for twice the first duration.

[0182] For example, the first junction temperature is within the temperature range of the third compressor, the second junction temperature is within the temperature range of the second external fan, the first duration is 5 seconds, the second frequency ramp-up rate is 10 Hz / s, and the second acceleration is 10 r / m. 2 If the controller increases the speed of the external fan by 50 r / s, and then detects a change rate of -5℃ in the first junction temperature within 5 seconds, and takes the first change threshold as 0℃, it indicates that the first junction temperature has decreased, and the controller increases the operating frequency of the compressor by 50 Hz.

[0183] The above embodiments, by gradually increasing the speed of the external fan and the frequency of the compressor, avoid the system from heating up too quickly during the performance improvement process, while ensuring stable system operation.

[0184] like Figure 7 The diagram shown is a schematic flowchart 700 illustrating an adjustment method for a slow descent phase according to an embodiment of this application. The method includes:

[0185] S701, the controller reduces the compressor's operating frequency at a first rate of reduction and reduces the speed of the external fan at a third rate of acceleration.

[0186] In some possible embodiments, when the first junction temperature of the compressor IPM module is in the fourth compressor temperature range and the second junction temperature of the outdoor fan IPM module is in the fourth compressor temperature range, the controller reduces the operating frequency of the compressor at a first frequency reduction rate and reduces the speed of the outdoor fan at a third acceleration.

[0187] S702, the controller acquires the rate of change of the first junction temperature over a second time period.

[0188] In some possible embodiments, the controller reduces the operating frequency of the compressor and the speed of the external fan during a second duration and detects the rate of change of the first junction temperature of the compressor IPM module during the second duration, the rate of change being the difference between the final value and the initial value of the first junction temperature.

[0189] S703, the controller determines whether the rate of change is less than the second change threshold.

[0190] In some possible embodiments, if the rate of change of the first junction temperature is less than the second change threshold, it indicates that the junction temperature of the compressor IPM module has increased less or decreased, and the speed of the external fan can be reduced more quickly; if the change of the first junction temperature is greater than or equal to the second change threshold, it indicates that the junction temperature of the compressor IPM module has increased more, and the operating frequency of the compressor should be reduced more quickly to further reduce the first junction temperature.

[0191] S704, the controller switches the acceleration of the external fan to the fourth acceleration.

[0192] In some possible embodiments, when the rate of change of the first junction temperature is less than the first change threshold, the controller reduces the operating frequency of the compressor at a first rate of reduction and reduces the speed of the external fan at a fourth acceleration, wherein the fourth acceleration is less than the third acceleration.

[0193] S705, the controller switches the compressor's frequency reduction rate to the second frequency reduction rate.

[0194] In some possible embodiments, when the rate of change of the first junction temperature is greater than or equal to the second change threshold, the controller reduces the operating frequency of the compressor at a first rate of reduction and reduces the speed of the external fan at a fourth acceleration, wherein the fourth acceleration is less than the third acceleration.

[0195] For example, the first junction temperature is within the temperature range of the fourth compressor, the second junction temperature is within the temperature range of the fourth external fan, the second duration is 10s, the first frequency rise rate is -10Hz / s, the second frequency fall rate is -20Hz / s, and the third acceleration is -10r / m. 2 The fourth acceleration is -20 r / m 2 If the controller reduces the compressor's operating frequency by 100Hz and the outdoor fan speed by 100r / s, and then detects a change rate of 5℃ in the first junction temperature within 10s, taking the second change threshold as 0℃, it indicates that the first junction temperature has increased. The controller then switches the compressor's frequency reduction rate to -20Hz / s, still operating at -10r / min. 2 The acceleration reduces the speed of the external fan.

[0196] The above embodiments can flexibly change the compressor's frequency reduction rate and the outdoor fan's deceleration acceleration when the IPM module junction temperature is high, so that the junction temperature of the compressor's IPM module and the outdoor fan's IPM module drops rapidly.

[0197] like Figure 8 The diagram shown is a schematic flowchart 800 of a junction overheat shutdown protection method provided in an embodiment of this application. The method includes the following steps:

[0198] S801, the controller obtains the first junction temperature and the second junction temperature.

[0199] Step S801 is similar to step S401, and will not be described again here.

[0200] S802, the controller determines whether the second junction temperature is within the temperature range of the fifth external fan.

[0201] In some possible embodiments, when the junction temperature of the outdoor fan IPM module is within the fifth outdoor fan temperature range, the controller determines that the junction temperature of the outdoor fan IPM module is over-temperature. If the junction temperature of the outdoor fan IPM module is not within the fifth outdoor fan temperature range, the controller needs to further determine whether the junction temperature of the compressor IPM module is over-temperature.

[0202] S803, the controller stops outputting the compressor PWM signal and the outdoor fan PWM signal.

[0203] In some possible embodiments, when the outdoor fan IPM module overheats, the controller needs to stop the PWM signal output of the outdoor fan, and the outdoor fan speed will drop rapidly to reduce the second junction temperature. After the outdoor fan is turned off, the compressor cannot be cooled. If the compressor continues to run, its first junction temperature will also overheat. Therefore, the controller also needs to stop the compressor PWM signal output to reduce the first junction temperature of the compressor.

[0204] S804, the controller determines whether the first junction temperature is within the temperature range of the fifth compressor.

[0205] In some possible embodiments, if the second junction temperature of the external fan is not overheated, it is necessary to further determine whether the first junction temperature of the compressor is overheated.

[0206] S805: When the first junction temperature is less than the compressor start-up temperature threshold, the controller outputs the compressor PWM signal; when the second junction temperature is less than the outdoor fan start-up temperature threshold, the controller outputs the outdoor fan PWM signal.

[0207] In some possible embodiments, when both the compressor's IPM module and the outdoor fan's IPM module are shut down due to overheating, the controller needs to wait until the compressor's first junction temperature drops to the compressor's start-up temperature threshold before outputting a compressor PWM control signal to increase the compressor's operating frequency, and wait until the compressor's second junction temperature drops to the outdoor fan's start-up temperature threshold before outputting an outdoor fan PWM control signal to increase the outdoor fan's speed.

[0208] S806, the controller stops outputting the compressor PWM signal, while the outdoor fan continues to run.

[0209] In some possible embodiments, when only the first junction temperature of the compressor's IPM module is overheated while the second junction temperature of the outdoor fan's IPM module is not overheated, the controller can simply stop the compressor's PWM signal output to shut down the compressor, while the outdoor fan can continue to run to cool the compressor's IPM module.

[0210] S807, the controller adjusts the compressor's operating rate and the outdoor fan's speed using other adjustment methods.

[0211] In some possible embodiments, when neither the first junction temperature of the compressor IPM module nor the second junction temperature of the outdoor fan IPM module exceeds the temperature limit, the operating frequency of the compressor and the speed of the outdoor fan can be adjusted according to the compressor temperature range and the outdoor fan temperature range where the first junction temperature and the second junction temperature are respectively located, in conjunction with the adjustment strategy in Table 1.

[0212] S808 When the first junction temperature is less than the compressor start-up temperature threshold, the controller outputs the compressor PWM signal.

[0213] In some possible embodiments, when the compressor's IPM module shuts down due to overheating, the controller needs to wait until the compressor's first junction temperature drops to the compressor's start-up temperature threshold before outputting a compressor PWM control signal to increase the compressor's operating frequency.

[0214] The above embodiment immediately stops the compressor and fan when the junction temperature of the IPM module is detected to be too high, preventing overheating damage to the equipment. This protection mechanism helps extend the service life of the equipment and improve system stability.

[0215] To implement the control method described above, the controller requires certain functional modules. The following description of the apparatus embodiments is similar to the description of the method embodiments described above, and has similar beneficial effects. For technical details not disclosed in the apparatus embodiments of this application, please refer to the description of the method embodiments of this application for understanding.

[0216] like Figure 9 The diagram shown is a schematic block diagram of a control device 900 provided in an embodiment of this application. The control device includes a junction temperature acquisition module 901 and a parameter adjustment module 902.

[0217] Junction temperature acquisition module 901 is used to acquire the first junction temperature and the second junction temperature.

[0218] In some possible embodiments, the junction temperature acquisition module 901 can calculate the first junction temperature and the second junction temperature based on the relevant parameters transmitted by the temperature sensor, the compressor IPM module, the external fan IPM module, and the memory.

[0219] The parameter adjustment module 902 is used to adjust the target parameters according to the first junction temperature and the second junction temperature.

[0220] In some possible embodiments, the parameter adjustment module 902 first determines the target compressor temperature range where the first junction temperature is located and the target external fan temperature range where the external fan is located, and adjusts the operating frequency of the compressor and the speed of the external fan according to the target compressor temperature range and the target external fan temperature range and in conjunction with Table 1.

[0221] The aforementioned functional modules work together to achieve coordinated regulation between the air conditioner's compressor and outdoor fan. Finally, the composition of the controller will be introduced.

[0222] like Figure 10 The diagram shown is a schematic block diagram of a controller 1000 provided in an embodiment of this application. The controller 1000 may include a processor 1010, a memory 1020, a bus 1030, and a device interface 1040.

[0223] The processor 1010 calls the executable program code stored in the memory 1020 to execute any of the air conditioner control methods disclosed in the embodiments of this application.

[0224] The memory 1020 stores executable program code, which is executed by the processor 1010 to implement any of the air conditioner control methods disclosed in the embodiments of this application.

[0225] Bus 1030 is used to transfer program code stored in memory 1020 to processor 1010 for execution.

[0226] Device interface 1040 is connected to bus 1030 to enable the processor 1010 and memory 1020 to connect with other devices.

[0227] Optionally, the memory 1020 may include read-only memory and random access memory, and provide instructions and data to the processor 1010. A portion of the memory 1020 may also include non-volatile random access memory. For example, the memory 1020 may also store device type information. The processor 1010 can be used to execute instructions stored in the memory, and when the processor executes the instructions, the processor 1010 can perform the various steps and / or processes corresponding to the terminal device in the above method embodiments.

[0228] It should be understood that, in the embodiments of this application, the processor may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0229] It should be noted that, Figure 10 The controller 1000 shown may also include components not shown, such as a power supply, which will not be described in detail in this embodiment.

[0230] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly manifested as execution by a hardware processor, or as a combination of hardware and software modules within the processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor executes the instructions in the memory, combining them with its hardware to complete the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0231] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0232] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0233] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0234] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0235] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0236] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to related technologies, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0237] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An air conditioner, characterized in that, The air conditioner includes: A compressor is used to compress the refrigerant circulating in the condenser, expansion valve, and evaporator. An outdoor fan is used to regulate the circulation of outdoor air. The controller is used to acquire the first junction temperature of the intelligent power module IPM of the compressor, acquire the second junction temperature of the intelligent power module IPM of the outdoor fan, adjust the operating frequency of the compressor, and adjust the speed of the outdoor fan. The controller is configured to: The first junction temperature and the second junction temperature are obtained, and the target parameters are adjusted according to the first junction temperature and the second junction temperature. The target parameters include the operating frequency of the compressor and / or the speed of the external fan.

2. The air conditioner according to claim 1, characterized in that, The controller adjusts the target parameters according to the first junction temperature and the second junction temperature, and is configured as follows: Determine the target compressor temperature range where the first junction temperature is located, and the target external fan temperature range where the second junction temperature is located; Based on the target compressor temperature range, the target outdoor fan temperature range, and a preset mapping relationship, the operating frequency of the compressor and the speed of the outdoor fan are adjusted. The preset mapping relationship includes multiple preset compressor temperature ranges, multiple preset outdoor fan temperature ranges, and multiple values ​​of the target parameter.

3. The air conditioner according to claim 2, characterized in that, The plurality of preset compressor temperature ranges include a first compressor temperature range, a second compressor temperature range, a third compressor temperature range, a fourth compressor temperature range, and a fifth compressor temperature range. The plurality of preset outdoor fan temperature ranges include a first outdoor fan temperature range, a second outdoor fan temperature range, a third outdoor fan temperature range, a fourth outdoor fan temperature range, and a fifth outdoor fan temperature range. The controller, based on the target compressor temperature range, the target outdoor fan temperature range, and a preset mapping relationship, adjusts the operating frequency of the compressor and the rotational speed of the outdoor fan, and is configured as follows: When the first junction temperature is within the temperature range of the first compressor and the second junction temperature is within the temperature range of the first external fan, the operating frequency of the compressor is increased by a first frequency increase rate and the rotational speed of the external fan is increased by a first acceleration. or, When the first junction temperature is within the temperature range of the second compressor and the second junction temperature is within the temperature range of the second external fan, the external fan speed is kept constant, and the operating frequency of the compressor is increased at the second frequency ramp rate; or, When the first junction temperature is within the temperature range of the third compressor and the second junction temperature is within the temperature range of the second external fan, the operating frequency of the compressor is kept constant, and the speed of the external fan is increased by the second acceleration. or, When the first junction temperature is within the temperature range of the third compressor and the second junction temperature is within the temperature range of the third external fan, the operating frequency of the compressor and the rotation speed of the external fan are kept constant. or, When the first junction temperature is within the temperature range of the fourth compressor and the second junction temperature is within the temperature range of the fourth external fan, the operating frequency of the compressor is reduced by a first frequency reduction rate and the speed of the external fan is reduced by a third acceleration. Wherein, the first up-frequency rate is greater than the second up-frequency rate, and the first acceleration is greater than the second acceleration.

4. The air conditioner according to claim 3, characterized in that, When the first junction temperature is within the temperature range of the third compressor and the second junction temperature is within the temperature range of the second external fan, after the controller maintains the operating frequency of the compressor unchanged and increases the speed of the external fan with a second acceleration, the controller is further configured to: After a first duration, the rate of change of the first junction temperature within the first duration is obtained, and the operating frequency of the compressor and the speed of the external fan are adjusted according to the rate of change of the first junction temperature and the first change threshold. If the rate of change of the first junction temperature is less than the first change threshold, the operating frequency of the compressor is increased by the target frequency value; If the rate of change of the first junction temperature is greater than or equal to the first change threshold, the rotational speed of the external fan is increased to the target rotational speed value.

5. The air conditioner according to claim 4, characterized in that, The target frequency value is the product of the first duration and the second frequency modulation rate; the target rotational speed value is twice the product of the first duration and the second acceleration.

6. The air conditioner according to claim 4, characterized in that, When the first junction temperature is within the temperature range of the fourth compressor and the second junction temperature is within the temperature range of the fourth outdoor fan, after the controller reduces the operating frequency of the compressor at a first reduction rate and reduces the speed of the outdoor fan at a third acceleration, the controller is further configured to: After the second time period, the rate of change of the first junction temperature during the second time period is obtained, and the operating frequency of the compressor and the speed of the external fan are adjusted according to the rate of change of the first junction temperature and the second change threshold. If the rate of change of the first junction temperature is less than the second change threshold, the rotational speed of the external fan is reduced by a fourth acceleration; If the rate of change of the first junction temperature is greater than or equal to the first change threshold, the operating frequency of the compressor is reduced at a second rate of reduction. Wherein, the fourth acceleration is greater than the third acceleration, and the second frequency reduction rate is greater than the first frequency reduction rate.

7. The air conditioner according to claim 3, characterized in that, The controller is also configured to: When the first junction temperature is within the temperature range of the fifth compressor and the second junction temperature is not within the temperature range of the fifth external fan, the compressor is shut down. When the second junction temperature is within the temperature range of the fifth external fan, the compressor and the external fan are shut down.

8. The air conditioner according to claim 7, characterized in that, After the controller shuts down the compressor, the controller is further configured to: Obtain the first junction temperature and determine whether the first junction temperature is less than the compressor start-up temperature threshold. The compressor is turned on when the first junction temperature is lower than the compressor start-up temperature threshold. After the controller shuts down the external fan, the controller is further configured to: Obtain the second junction temperature and determine whether the second junction temperature is less than the outdoor fan start-up temperature threshold. When the second junction temperature is lower than the outdoor fan start-up temperature threshold, the outdoor fan is turned on. Wherein, the compressor start-up temperature threshold is located within the first compressor temperature range, and the outdoor fan start-up temperature threshold is located within the first outdoor fan temperature range.

9. The air conditioner according to any one of claims 1-8, characterized in that, The junction temperature of the intelligent power module (IPM) is equal to the sum of the ambient temperature and the temperature rise, where the temperature rise is equal to the product of the device power loss and the ambient thermal resistance.

10. The air conditioner according to claim 9, characterized in that, The power loss of the device is determined by the power loss of a single insulated gate bipolar transistor (IGBT) and the power loss of a fast recovery diode (FRD). The power loss of the IGBT includes the IGBT's conduction power loss and the IGBT's switching power loss, and the power loss of the FRD includes the FRD's conduction power loss and the FRD's reverse recovery power loss.

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