Oil return control method and device of solar air conditioner and air conditioning system

Abstract

The invention relates to the technical field of air conditioners, and provides an oil return control method and device of a solar air conditioner and an air conditioning system.The method comprises the steps that when the solar air conditioner is in a low-frequency running state, whether a preset oil return triggering condition is met or not is judged; when conditions are met, the current oil temperature of refrigerant oil is obtained; when the oil temperature is smaller than a preset oil return temperature threshold value, a stepped frequency increasing strategy for the compressor to enter an oil return mode is determined, and the compressor is controlled to operate according to the stepped frequency increasing strategy; and if the solar power supply system does not meet the power required for maintaining the operation of the stepped frequency raising strategy, triggering the multi-energy complementary machine. The compressor is controlled to gradually increase the frequency according to the stepped frequency increasing strategy, so that the frequency of the compressor is in smooth transition, transient load impact in the oil return process is buffered, stable operation of the compressor is guaranteed, and the service life of an air conditioning system is prolonged; and auxiliary energy is introduced through a multi-energy complementary mechanism for power compensation, stable power supply in the oil return process is guaranteed, and then the operation reliability of the system is improved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a method, apparatus and air conditioning system for controlling oil return in a solar-powered air conditioner. Background Technology

[0002] With the continuous development of new energy technologies, solar air conditioning, as an energy-saving and environmentally friendly cooling and heating device, has been widely used. Currently, solar air conditioning typically uses photovoltaic panels to provide electricity to the compressor, thereby reducing the system's dependence on mains power and achieving the goal of energy conservation and emission reduction.

[0003] During the actual operation of solar air conditioners, especially at low frequencies, the refrigerant flow rate in the system pipelines is slow due to the low compressor speed. This condition can easily cause refrigerant oil to stagnate in the pipelines and heat exchangers, preventing it from returning smoothly to the compressor. If the compressor operates in a state of oil deficiency for a long time, it will lead to poor lubrication of its internal moving parts (such as scroll plates and bearings), thereby affecting the service life and operational reliability of the air conditioning system.

[0004] To address these issues, existing solar air conditioners employ a timed oil return control strategy, which forces the system into a high-frequency oil return mode based on the compressor's cumulative operating time. However, in practical applications, this forced oil return method can easily cause the compressor to wear out or jam due to excessive instantaneous load, thereby reducing the air conditioner's lifespan and reliability. Summary of the Invention

[0005] This invention provides a method, device, and air conditioning system for controlling oil return in a solar-powered air conditioner. It addresses the shortcomings of existing technologies that employ timed forced oil return strategies, which can lead to compressor wear or jamming due to excessive instantaneous load. This invention achieves safe and stable oil return, extends the service life of the air conditioner, and improves the reliability of system operation.

[0006] This invention provides a method for controlling oil return in a solar-powered air conditioner, comprising: When the solar air conditioner is operating at low frequency, it is determined whether the preset oil return trigger condition is met based on the operating parameters of the solar air conditioner. Under the condition that the preset oil return triggering condition is met, obtain the current oil temperature of the refrigeration oil; When the current oil temperature is less than the preset oil return temperature threshold, a stepped frequency increase strategy for the compressor to enter the oil return mode is determined, and the compressor is controlled to operate according to the stepped frequency increase strategy, wherein the stepped frequency increase strategy includes a frequency increase step size and a corresponding frequency increase time interval. During the process of controlling the compressor to operate according to the stepped frequency increase strategy, if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, a multi-energy complementary mechanism is triggered to introduce auxiliary energy for power compensation.

[0007] According to the present invention, a method for controlling the oil return of a solar-powered air conditioner, wherein determining the step-up frequency increase strategy for the compressor to enter the oil return mode includes: Based on the current oil temperature and the preset low temperature range, the corresponding frequency increase step size and frequency increase time interval are determined.

[0008] According to the present invention, a method for controlling the oil return of a solar-powered air conditioner includes a preset low-temperature range comprising a first low-temperature range and a second low-temperature range, wherein the temperature value of the first low-temperature range is less than the temperature value of the second low-temperature range; the step of determining the corresponding frequency ramp step size and frequency ramp time interval based on the current oil temperature and the preset low-temperature range includes: When the current oil temperature is in the first low temperature range, the stepped frequency increase strategy is determined to use a first frequency increase step size and a first frequency increase time interval; When the current oil temperature is in the second low temperature range, the stepped frequency increase strategy is determined to use a second frequency increase step size and a second frequency increase time interval. Wherein, the first frequency upsampling step size is smaller than the second frequency upsampling step size, and the first frequency upsampling time interval is smaller than the second frequency upsampling time interval.

[0009] According to the present invention, a method for controlling the return oil of a solar-powered air conditioner, wherein if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, a multi-energy complementary mechanism is triggered, including: Obtain the real-time power demand required to maintain the stepped frequency increase strategy, and obtain the real-time output power of the solar power system; When the real-time output power is less than the real-time demand power, the multi-energy complementarity mechanism is triggered.

[0010] According to the present invention, a method for controlling oil return in a solar-powered air conditioner, wherein the triggering of the multi-energy complementary mechanism includes: Determine the power difference between the real-time demand power and the real-time output power; The auxiliary energy source is controlled to provide power compensation according to the power difference; wherein the auxiliary energy source includes mains power and / or energy storage units.

[0011] According to the present invention, a method for controlling the oil return of a solar-powered air conditioner includes determining whether a preset oil return trigger condition is met based on the operating parameters of the solar-powered air conditioner, comprising: Obtain the continuous operating time of the compressor; If the continuous running time is greater than or equal to a preset running time threshold, it is determined that the preset oil return trigger condition is met.

[0012] According to the present invention, a method for controlling oil return in a solar-powered air conditioner further includes: When the current oil temperature is greater than or equal to the preset oil return temperature threshold, the compressor is controlled to operate at the preset target oil return frequency.

[0013] According to the present invention, a method for controlling oil return in a solar-powered air conditioner further includes: During the process of controlling the compressor to operate according to the stepped frequency increase strategy, the discharge temperature of the compressor and the condensing pressure in the pipeline are obtained; Based on the exhaust temperature and the condensation pressure, determine the current estimated viscosity of the retained refrigeration oil; When the current estimated viscosity drops to a preset safe lubrication threshold, the solar air conditioner is controlled to exit the oil return mode.

[0014] The present invention also provides an oil return control device for a solar air conditioner, comprising: The judgment module is used to determine whether the preset oil return trigger condition is met based on the operating parameters of the solar air conditioner when the solar air conditioner is in a low-frequency operation state. The acquisition module is used to acquire the current oil temperature of the refrigeration oil when the preset oil return trigger conditions are met. The control module is used to determine the step-up frequency increase strategy for the compressor to enter the oil return mode when the current oil temperature is less than the preset oil return temperature threshold, and to control the compressor to operate according to the step-up frequency increase strategy, wherein the step-up frequency increase strategy includes the frequency increase step size and the corresponding frequency increase time interval. The triggering module is used to trigger a multi-energy complementary mechanism to introduce auxiliary energy for power compensation when the real-time output power of the solar power supply system is insufficient to maintain the operation of the stepped frequency increase strategy during the process of controlling the compressor to operate according to the stepped frequency increase strategy.

[0015] The present invention also provides an air conditioning system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the oil return control method of the solar air conditioner as described in any of the above.

[0016] The oil return control method for solar air conditioners provided by this invention determines whether the oil return triggering condition is met based on operating parameters when the solar air conditioner is in a low-frequency operating state. If the condition is met, the current oil temperature of the compressor is obtained. If the current oil temperature is less than a preset oil return temperature threshold, a stepped frequency increase strategy for the compressor to enter the oil return mode is determined. The compressor is controlled to gradually increase its operating frequency according to the step size and corresponding time interval of the stepped frequency increase strategy, so that the compressor frequency transitions smoothly, effectively mitigating the transient load impact during the oil return process, ensuring the stable operation of the compressor, and thus extending the service life of the air conditioning system. At the same time, during the stepped frequency increase oil return process, if the real-time output power of the solar power supply system is insufficient to maintain the power required for the operation of this strategy, a multi-energy complementary mechanism is triggered to introduce auxiliary energy for power compensation, ensuring a stable power supply during the oil return process, thereby improving the reliability of the solar air conditioner under low-frequency conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is one of the flowcharts illustrating the oil return control method for solar air conditioning provided by the present invention.

[0019] Figure 2 This is the second flowchart of the oil return control method for solar air conditioning provided by the present invention.

[0020] Figure 3 This is the third flowchart of the oil return control method for solar air conditioning provided by the present invention.

[0021] Figure 4 This is the fourth flowchart of the oil return control method for solar air conditioning provided by the present invention.

[0022] Figure 5 This is the fifth flowchart of the oil return control method for solar air conditioning provided by the present invention.

[0023] Figure 6 This is the sixth flowchart of the oil return control method for solar air conditioning provided by the present invention.

[0024] Figure 7 This is a schematic diagram of the oil return control device for solar air conditioning provided by the present invention.

[0025] Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The following is combined Figures 1 to 7 The present invention describes the oil return control method, apparatus, and air conditioning system of a solar-powered air conditioner.

[0028] An embodiment of the present invention proposes a method for controlling oil return in a solar-powered air conditioner, such as... Figure 1 As shown, the method includes the following steps: Step 100: When the solar air conditioner is in a low-frequency operation state, determine whether the preset oil return trigger condition is met based on the operating parameters of the solar air conditioner.

[0029] Understandably, during operation, a solar-powered air conditioner's compressor adjusts its operating frequency according to indoor and outdoor load demands, and the electrical energy required for compressor operation is provided by a solar power system. This system includes photovoltaic panels, a controller, and an energy storage unit. The photovoltaic panels convert solar energy into electrical energy to power the compressor, and excess energy is stored in the storage unit. When the system is under partial load (e.g., indoor temperature close to the set temperature, outdoor ambient temperature suitable), the compressor enters a low-frequency operating state to maintain stable system operation and reduce energy consumption. Low-frequency operation refers to a mode where the compressor's operating frequency is below a preset frequency threshold, such as below 30Hz or below 40% of the rated frequency. Specific thresholds can be set based on the compressor model, system design, and actual application scenario.

[0030] Under low-frequency operation, the compressor speed is low, and the refrigerant flow rate in the system pipeline is slow. This reduces the refrigerant's ability to carry refrigerant oil back to the compressor, easily leading to oil buildup in pipelines, heat exchangers, and gas-liquid separators. If the compressor operates in an oil-deficient state for an extended period, it will affect the lubrication of its internal moving parts. Therefore, this embodiment first determines whether the solar air conditioner is operating at low frequency. Based on this, it determines whether the oil return trigger condition is met according to operating parameters (such as the compressor's continuous low-frequency operation time, exhaust temperature, system pressure, etc.). For example, when the compressor's continuous low-frequency operation time reaches a preset time threshold, it can be determined that the oil return trigger condition is met, thereby initiating the subsequent oil return control process.

[0031] Step 200: Under the condition that the preset oil return triggering condition is met, obtain the current oil temperature of the refrigeration oil.

[0032] Specifically, once the oil return trigger condition is met, the current oil temperature of the refrigeration oil (lubricating oil) is obtained through a temperature sensor or other detection device. Refrigeration oil has the physical characteristic that its viscosity changes with temperature, and the oil temperature affects its flowability. When the oil temperature is low, the refrigeration oil has a higher viscosity and poorer flowability. If the compressor is forcibly driven to operate at a high frequency (target oil return frequency) at this time, the refrigeration oil cannot flow back to the moving parts inside the compressor (such as the scroll plate, bearings, etc.) in time, which can easily lead to dry friction of the parts due to insufficient lubrication, causing severe wear or even seizure. Therefore, the current oil temperature obtained in this embodiment is used to subsequently determine whether the compressor has the conditions to safely enter the normal oil return mode and to determine a suitable oil return control strategy, avoiding forced high-frequency oil return operation when the refrigeration oil viscosity is too high.

[0033] Step 300: When the current oil temperature is lower than the preset oil return temperature threshold, determine the step frequency increase strategy for the compressor to enter the oil return mode, and control the compressor to operate according to the step frequency increase strategy. The step frequency increase strategy includes the frequency increase step size and the corresponding frequency increase time interval.

[0034] Understandably, the current oil temperature is compared with a preset oil return temperature threshold. If the current oil temperature is lower than the preset oil return temperature threshold, it indicates that the refrigeration oil temperature is low and its fluidity is poor, indicating a need for oil return. In this case, the compressor enters the oil return mode, and a stepped frequency increase strategy is used to control the compressor's operation. The stepped frequency increase strategy means that the compressor does not directly increase to the high frequency (target oil return frequency), but gradually increases the operating frequency according to a preset frequency increase step size. After each frequency increase, it maintains that frequency for a preset frequency increase time interval until the compressor adapts to the frequency before proceeding to the next frequency increase. For example, it can be set to increase the frequency by 5Hz each time, and maintain operation for 30 seconds after each frequency increase until oil return is completed or the target oil return frequency is reached. This gradual frequency increase method can avoid mechanical shock and wear to the compressor due to excessive instantaneous load.

[0035] Step 400: During the operation of the compressor according to the stepped frequency increase strategy, if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, the multi-energy complementarity mechanism is triggered to introduce auxiliary energy for power compensation.

[0036] Understandably, in solar-powered air conditioners, the electrical energy required for compressor operation is provided by a solar power system. However, the output power of this system may fluctuate due to factors such as sunlight intensity and weather changes. During the oil return process following a stepped frequency ramp-up strategy, if the real-time output power of the solar power system is lower than the power required to maintain the current frequency ramp-up strategy, the compressor may be unable to maintain the required oil return frequency, or even experience an interruption in oil return. Therefore, this step monitors the output power of the solar power system in real-time and compares it with the real-time power demand required to maintain the stepped frequency ramp-up strategy. When the real-time output power is less than the real-time power demand, a multi-energy complementarity mechanism is triggered, introducing auxiliary energy sources such as mains power or energy storage units for power compensation. This ensures that the compressor can stably complete the oil return operation according to the preset stepped frequency ramp-up strategy, guaranteeing the continuity and reliability of the oil return process.

[0037] The oil return control method for solar air conditioners provided in this invention determines whether the oil return triggering condition is met based on operating parameters when the solar air conditioner is in a low-frequency operating state. If the condition is met, the current oil temperature of the compressor is obtained. If the current oil temperature is less than a preset oil return temperature threshold, a stepped frequency increase strategy for the compressor to enter the oil return mode is determined. The compressor is controlled to gradually increase its operating frequency according to the step size and corresponding time interval of the stepped frequency increase strategy, so that the compressor frequency transitions smoothly, effectively mitigating the transient load impact during the oil return process, ensuring the stable operation of the compressor, and thus extending the service life of the air conditioning system. At the same time, during the stepped frequency increase oil return process, if the real-time output power of the solar power supply system is insufficient to maintain the power required for the operation of this strategy, a multi-energy complementary mechanism is triggered to introduce auxiliary energy for power compensation, ensuring a stable power supply during the oil return process, thereby improving the reliability of the solar air conditioner under low-frequency conditions.

[0038] In one embodiment of the present invention, step 300, determining the stepped frequency increase strategy for the compressor to enter the oil return mode, may specifically include the following: Based on the current oil temperature and the preset low temperature range, determine the corresponding frequency ramp step size and frequency ramp time interval.

[0039] Specifically, when the current oil temperature is determined to be lower than the preset oil return temperature threshold, it indicates that the refrigeration oil temperature is low and the viscosity is high. If forced oil return is performed directly at high frequency (target oil return frequency) at this time, the compressor may be damaged due to excessive instantaneous load. Therefore, this embodiment determines the stepped frequency increase strategy when the compressor enters the oil return mode based on the specific low temperature range of the current oil temperature, that is, sets the corresponding frequency increase step size and the corresponding frequency increase time interval.

[0040] Understandably, the viscosity of refrigeration oil increases as temperature decreases. The lower the oil temperature, the worse the fluidity of the refrigeration oil, and the greater the mechanical stress on the internal moving parts of the compressor (such as the scroll plate and bearings) during the oil return process. To reduce transient impact on the compressor while ensuring effective oil return, the temperature range below the preset oil return temperature threshold is divided into several different low-temperature zones; the corresponding frequency increase step size and frequency increase time interval are matched according to the low-temperature zone to which the current oil temperature belongs.

[0041] The lower the current oil temperature is in the low-temperature range, the smaller the corresponding frequency increase step size and the shorter the frequency increase time interval. This is to reduce the transient mechanical impact on the moving parts inside the compressor by using a step-like frequency increase method with small step size and short interval, thereby protecting the compressor.

[0042] Optionally, the preset low-temperature range includes a first low-temperature range and a second low-temperature range, wherein the temperature value of the first low-temperature range is lower than the temperature value of the second low-temperature range; for example... Figure 2 As shown, step 300, based on the current oil temperature and the preset low-temperature range, determines the corresponding frequency ramp-up step size and frequency ramp-up time interval, which may specifically include the following steps: Step 310: When the current oil temperature is in the first low temperature range, determine the first frequency increase step size and the first frequency increase time interval for the stepped frequency increase strategy.

[0043] Step 320: When the current oil temperature is in the second low temperature range, determine the step frequency increase strategy to use the second frequency increase step size and the second frequency increase time interval; wherein, the first frequency increase step size is smaller than the second frequency increase step size, and the first frequency increase time interval is smaller than the second frequency increase time interval.

[0044] In this embodiment, a preset return oil temperature threshold is denoted as the first temperature threshold T1, and a second temperature threshold T2 is set within the temperature range below the first temperature threshold T1, where T2 < T1. Based on this, the temperature range below T1 is divided into two sub-ranges: the first low-temperature range is the temperature range less than T2, and the second low-temperature range is the temperature range greater than or equal to T2 and less than T1.

[0045] When the temperature of the refrigeration oil is in the first low temperature range (oil temperature < T2), for example, T2 can be set to 0℃, the refrigeration oil has a high viscosity and poor fluidity. A smaller first frequency increase step size (e.g., 5Hz each time) and a shorter first frequency increase time interval (e.g., keep running for 1 minute after each frequency increase) are used to make the compressor frequency increase slowly, giving the refrigeration oil sufficient time to return and avoid insufficient lubrication caused by sudden frequency changes.

[0046] When the refrigeration oil temperature is in the second low-temperature range (T2 ≤ oil temperature < T1), for example, T2 is 0℃ and T1 is 5℃, the refrigeration oil viscosity decreases, its fluidity improves, and it can withstand relatively rapid frequency increases. Therefore, within this temperature range, a larger second frequency increase step size (e.g., 10Hz per increase) and a longer second frequency increase interval (e.g., maintaining operation for 3 minutes after each frequency increase) are used to appropriately accelerate the oil return process and shorten the oil return duration, while ensuring timely oil oil return. By matching different frequency increase steps and frequency increase intervals according to different oil temperature ranges, the oil return efficiency is optimized while ensuring the safe operation of the compressor.

[0047] In one embodiment of the present invention, such as Figure 3 As shown, step 400 may specifically include the following steps: Step 410: Obtain the real-time power demand required to maintain the stepped frequency increase strategy, and obtain the real-time output power of the solar power system.

[0048] Among them, real-time demand power refers to the electrical power consumed by the compressor at the current moment during the process of running to the target oil return frequency according to the current frequency increase step size and frequency increase time interval. This power value can be calculated in real time based on the compressor's current operating frequency, load status and system operating parameters. Real-time output power refers to the electrical power that the solar power supply system can actually provide under the current light conditions and operating status, which can be obtained in real time through the power detection device set at the output end of the photovoltaic panel.

[0049] Step 420: When the real-time output power is less than the real-time demand power, trigger the multi-energy complementarity mechanism.

[0050] Understandably, comparing real-time output power with real-time demand power reveals that when the output power is less than the demand, it indicates that the current power generation capacity of the solar power system is insufficient to support the compressor's continued operation according to the stepped frequency ramp-up strategy. Continued reliance on solar power could lead to a decrease in compressor frequency or interruption of oil return. In this situation, a multi-energy complementarity mechanism is triggered, introducing auxiliary energy (such as mains power or energy storage units) for power compensation. This ensures the compressor can stably complete the oil return operation according to the stepped frequency ramp-up strategy, thereby promptly initiating power compensation when solar power is insufficient, ensuring the continuity and reliability of the oil return process.

[0051] Optional, such as Figure 4 As shown, in step 400, the multi-energy complementarity mechanism is triggered, which may specifically include the following steps: Step 430: Determine the power difference between the real-time demand power and the real-time output power.

[0052] Step 440: Control the auxiliary energy to compensate for the power difference and supply power.

[0053] Understandably, the power difference between the real-time demand power and the real-time output power is determined. This difference represents the current power deficit of the solar power system, indicating the additional electrical energy required to maintain the stable operation of the stepped frequency ramp strategy. Auxiliary energy sources, including mains power and / or energy storage units, are controlled to compensate for this power difference. Specifically, when the energy storage unit has sufficient stored power, it can be prioritized to discharge for power compensation, fully utilizing the energy stored in the solar system. When the energy storage unit has insufficient power or when prioritizing energy storage lifespan, it can switch to mains power for compensation, or mains power and the energy storage unit can work together to supplement the power deficit. This eliminates DC bus voltage fluctuations caused by insufficient power during the stepped frequency ramp process, ensuring the bus voltage remains stable within the range required for normal compressor operation. It avoids compressor frequency fluctuations, operational instability, or even shutdown protection caused by voltage fluctuations, thus ensuring the smooth execution of the stepped frequency ramp oil return process.

[0054] In one embodiment of the present invention, such as Figure 5 As shown, in step 100, based on the operating parameters of the solar air conditioner, it is determined whether the preset oil return trigger condition is met, which may specifically include the following: Step 110: Obtain the continuous running time of the compressor.

[0055] The continuous running time is the total duration of continuous operation of the compressor since its start-up, or the cumulative duration of continuous operation of the compressor in low-frequency operation mode, which can be obtained in real time through the timing module inside the controller.

[0056] Step 120: If the continuous running time is greater than or equal to the preset running time threshold, determine that the preset oil return trigger condition is met.

[0057] Understandably, after prolonged compressor operation, especially when operating at low frequencies for extended periods, refrigerant oil gradually accumulates in the pipes and heat exchanger, leading to an increased demand for oil return. By setting a time threshold, the oil return control process can be triggered promptly when the accumulated demand reaches a certain level, preventing compressor operation due to insufficient oil return. Specifically, the acquired continuous operating time is compared with a preset time threshold. When the continuous operating time is greater than or equal to the preset time threshold, the preset oil return trigger condition is deemed met. The preset time threshold can be set according to the compressor model and the actual application scenario; for example, it can be set to 2 hours.

[0058] It should be noted that the use of continuous running time as the criterion for oil return triggering in this embodiment is only an exemplary implementation. In practical applications, the oil return triggering condition can also be set according to other operating parameters. For example, the compressor's exhaust superheat can be detected. When the exhaust superheat is lower than a preset superheat threshold, it indicates that there is too much refrigerant in the system, and the refrigeration oil may be diluted or stagnant, thus triggering oil return. Alternatively, the compressor's operating current or power fluctuations can be detected. When abnormal fluctuations occur in the current or power, it may indicate poor lubrication of the compressor, requiring the initiation of oil return. In addition, multiple operating parameters can be combined for comprehensive judgment. For example, continuous running time and exhaust superheat can be combined, and oil return can be triggered only when both meet their respective preset conditions, thereby improving the accuracy and reliability of oil return triggering.

[0059] In one embodiment of the present invention, the method further includes the following steps: Step 500: Control the solar air conditioner to exit the oil return mode.

[0060] Optionally, such as Figure 6 As shown, step 500 may specifically include the following steps: Step 510: During the process of controlling the compressor to operate according to the stepped frequency increase strategy, obtain the compressor's discharge temperature and the condensing pressure in the pipeline.

[0061] Step 520: Determine the current estimated viscosity of the retained refrigeration oil based on the exhaust temperature and condensation pressure.

[0062] Step 530: When the current estimated viscosity drops to the preset safe lubrication threshold, control the solar air conditioner to exit the oil return mode.

[0063] Understandably, during the process of controlling the compressor to return oil according to the stepped frequency increase strategy, the compressor's discharge temperature and the condensing pressure in the pipeline are acquired in real time. The discharge temperature can be obtained through a temperature sensor installed on the compressor's discharge pipeline, and the condensing pressure can be obtained through a pressure sensor installed at the condenser inlet or outlet. Based on the acquired discharge temperature and condensing pressure, the current estimated viscosity of the retained refrigerant oil is determined. The viscosity of the refrigerant oil has a physical correspondence with temperature and pressure. The discharge temperature reflects the current temperature state of the refrigerant oil, and the condensing pressure reflects the current load condition of the system, thus allowing the current estimated viscosity of the retained refrigerant oil to be calculated without the need for an additional oil viscosity detection sensor. The current estimated viscosity is compared with a preset safe lubrication threshold. When the current estimated viscosity drops below the preset safe lubrication threshold, it indicates that the refrigerant oil retained in the pipeline has fully returned to the compressor, the oil volume inside the compressor has been restored, and the lubrication conditions have improved, indicating that the oil return process is complete. At this point, the solar air conditioner is controlled to exit the oil return mode, allowing the system to return to normal operation.

[0064] In one embodiment of the present invention, after performing step 500, the method further includes the following: The compressor is controlled to return to the preset low-frequency operating state; and the power supply of the mains power or the energy storage unit is gradually reduced until it is cut off, so as to restore the operation mode mainly powered by solar energy.

[0065] Understandably, after the solar-powered air conditioner exits the oil return mode, the compressor's operating frequency gradually decreases and returns to the preset low-frequency operating state before the oil return, allowing the system to re-enter the energy-saving operation mode. Simultaneously, regarding the multi-energy complementarity mechanism, the compensating power supply from the mains power or energy storage unit is gradually reduced, ensuring a smooth transition of power supply from auxiliary energy back to the solar power system. Specifically, based on the compressor's actual operating power requirements, the output power of the mains power or energy storage unit is gradually reduced according to a preset decreasing step size, correspondingly increasing the proportion of power supplied by the solar power system, until the compensating power supply from the auxiliary energy is completely cut off, and the system returns to a solar-powered operation mode.

[0066] In one embodiment of the present invention, the method further includes the following steps: Step 600: When the current oil temperature is greater than or equal to the preset oil return temperature threshold, control the compressor to run at the preset target oil return frequency.

[0067] Understandably, after obtaining the compressor's current oil temperature, it is compared with a preset oil return temperature threshold. If the current oil temperature is greater than or equal to the preset oil return temperature threshold, it indicates that the refrigeration oil temperature is already in a high range, its viscosity is within the optimal design range, and it has good fluidity, easily following the refrigerant gas to flow at high speed in the pipeline. At this time, the internal moving parts of the compressor have been fully preheated and are capable of withstanding high-load operation. In this case, there is no need to use a stepped frequency increase strategy to slowly increase the frequency; the compressor can be directly controlled to operate at the preset target oil return frequency, allowing it to quickly enter the high-frequency oil return mode and rapidly bring the refrigeration oil stagnating in the pipeline and heat exchanger back to the compressor. Thus, when oil temperature conditions permit, directly using the traditional conventional high-frequency oil return method can shorten the oil return duration and improve oil return efficiency while ensuring the safe operation of the compressor.

[0068] The oil return control device for solar air conditioning provided by the present invention will be described below. The oil return control device for solar air conditioning described below can be referred to in correspondence with the oil return control method for solar air conditioning described above.

[0069] Embodiments of the present invention also propose an oil return control device for solar air conditioning, such as... Figure 7 As shown, the control device includes a judgment module 701, an acquisition module 702, a control module 703, and a trigger module 704.

[0070] The judgment module 701 is used to determine whether the preset oil return trigger condition is met based on the operating parameters of the solar air conditioner when the solar air conditioner is in a low-frequency operation state.

[0071] The acquisition module 702 is used to acquire the current oil temperature of the refrigeration oil when the preset oil return trigger conditions are met.

[0072] The control module 703 is used to determine the step frequency increase strategy for the compressor to enter the oil return mode when the current oil temperature is lower than the preset oil return temperature threshold, and to control the compressor to operate according to the step frequency increase strategy. The step frequency increase strategy includes the frequency increase step size and the corresponding frequency increase time interval.

[0073] The trigger module 704 is used to trigger a multi-energy complementary mechanism to introduce auxiliary energy for power compensation when the real-time output power of the solar power supply system is insufficient to maintain the operation of the step-up frequency strategy during the operation of the compressor.

[0074] The embodiments of the present invention also propose an air conditioning system, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the oil return control method of the solar air conditioner provided in any of the above embodiments.

[0075] Figure 8 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840. The processor 810, communication interface 820, and memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute a solar air conditioner oil return control method. This method includes: when the solar air conditioner is in a low-frequency operating state, determining whether a preset oil return trigger condition is met based on the operating parameters of the solar air conditioner; if the preset oil return trigger condition is met, obtaining the current oil temperature of the refrigerant oil; if the current oil temperature is lower than a preset oil return temperature threshold, determining a stepped frequency increase strategy for the compressor to enter the oil return mode, and controlling the compressor to operate according to the stepped frequency increase strategy, wherein the stepped frequency increase strategy includes a frequency increase step size and a corresponding frequency increase time interval; during the process of controlling the compressor to operate according to the stepped frequency increase strategy, if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, triggering a multi-energy complementary mechanism to introduce auxiliary energy for power compensation.

[0076] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part 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 of the various embodiments of the present invention. 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.

[0077] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the oil return control method for solar air conditioning provided by the above methods. The method includes: when the solar air conditioning is in a low-frequency operation state, determining whether a preset oil return trigger condition is met based on the operating parameters of the solar air conditioning; if the preset oil return trigger condition is met, obtaining the current oil temperature of the refrigeration oil; if the current oil temperature is less than a preset oil return temperature threshold, determining a stepped frequency increase strategy for the compressor to enter the oil return mode, and controlling the compressor to operate according to the stepped frequency increase strategy, wherein the stepped frequency increase strategy includes a frequency increase step size and a corresponding frequency increase time interval; during the process of controlling the compressor to operate according to the stepped frequency increase strategy, if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, triggering a multi-energy complementary mechanism to introduce auxiliary energy for power compensation.

[0078] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the oil return control method for a solar-powered air conditioner provided by the above methods. The method includes: when the solar-powered air conditioner is in a low-frequency operating state, determining whether a preset oil return trigger condition is met based on the operating parameters of the solar-powered air conditioner; if the preset oil return trigger condition is met, obtaining the current oil temperature of the refrigeration oil; if the current oil temperature is less than a preset oil return temperature threshold, determining a stepped frequency increase strategy for the compressor to enter the oil return mode, and controlling the compressor to operate according to the stepped frequency increase strategy, wherein the stepped frequency increase strategy includes a frequency increase step size and a corresponding frequency increase time interval; during the process of controlling the compressor to operate according to the stepped frequency increase strategy, if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, triggering a multi-energy complementary mechanism to introduce auxiliary energy for power compensation.

[0079] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and 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 modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0080] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling oil return in a solar-powered air conditioner, characterized in that, include: When the solar air conditioner is operating at low frequency, it is determined whether the preset oil return trigger condition is met based on the operating parameters of the solar air conditioner. Under the condition that the preset oil return triggering condition is met, obtain the current oil temperature of the refrigeration oil; When the current oil temperature is less than the preset oil return temperature threshold, a stepped frequency increase strategy for the compressor to enter the oil return mode is determined, and the compressor is controlled to operate according to the stepped frequency increase strategy, wherein the stepped frequency increase strategy includes a frequency increase step size and a corresponding frequency increase time interval. During the process of controlling the compressor to operate according to the stepped frequency increase strategy, if the real-time output power of the solar power supply system does not meet the power required to maintain the operation of the stepped frequency increase strategy, a multi-energy complementarity mechanism is triggered to introduce auxiliary energy for power compensation.

2. The oil return control method for solar air conditioning according to claim 1, characterized in that, The step-up frequency increase strategy for determining when the compressor enters the oil return mode includes: Based on the current oil temperature and the preset low temperature range, the corresponding frequency increase step size and frequency increase time interval are determined.

3. The oil return control method for solar air conditioning according to claim 2, characterized in that, The preset low temperature range includes a first low temperature range and a second low temperature range, wherein the temperature value of the first low temperature range is lower than the temperature value of the second low temperature range; The step of determining the corresponding frequency ramping step size and frequency ramping time interval based on the current oil temperature and a preset low-temperature range includes: When the current oil temperature is in the first low temperature range, the stepped frequency increase strategy is determined to use a first frequency increase step size and a first frequency increase time interval; When the current oil temperature is in the second low temperature range, the stepped frequency increase strategy is determined to use a second frequency increase step size and a second frequency increase time interval. Wherein, the first frequency upsampling step size is smaller than the second frequency upsampling step size, and the first frequency upsampling time interval is smaller than the second frequency upsampling time interval.

4. The oil return control method for solar air conditioning according to claim 1, characterized in that, If the real-time output power of the solar power system does not meet the power requirements for maintaining the operation of the stepped frequency increase strategy, the multi-energy complementarity mechanism is triggered, including: Obtain the real-time power demand required to maintain the stepped frequency increase strategy, and obtain the real-time output power of the solar power system; When the real-time output power is less than the real-time demand power, the multi-energy complementarity mechanism is triggered.

5. The oil return control method for solar air conditioning according to claim 4, characterized in that, The triggering multi-energy complementarity mechanism includes: Determine the power difference between the real-time demand power and the real-time output power; The auxiliary energy source is controlled to provide power compensation according to the power difference; wherein the auxiliary energy source includes mains power and / or energy storage units.

6. The oil return control method for solar air conditioning according to claim 1, characterized in that, The determination of whether the preset oil return trigger condition is met based on the operating parameters of the solar-powered air conditioner includes: Obtain the continuous operating time of the compressor; If the continuous running time is greater than or equal to a preset running time threshold, it is determined that the preset oil return trigger condition is met.

7. The oil return control method for solar air conditioning according to claim 1, characterized in that, The method further includes: When the current oil temperature is greater than or equal to the preset oil return temperature threshold, the compressor is controlled to operate at the preset target oil return frequency.

8. The oil return control method for solar air conditioning according to any one of claims 1 to 7, characterized in that, The method further includes: During the process of controlling the compressor to operate according to the stepped frequency increase strategy, the discharge temperature of the compressor and the condensing pressure in the pipeline are obtained; Based on the exhaust temperature and the condensation pressure, determine the current estimated viscosity of the retained refrigeration oil; When the current estimated viscosity drops to a preset safe lubrication threshold, the solar air conditioner is controlled to exit the oil return mode.

9. A solar-powered air conditioner oil return control device, characterized in that, include: The judgment module is used to determine whether the preset oil return trigger condition is met based on the operating parameters of the solar air conditioner when the solar air conditioner is in a low-frequency operation state. The acquisition module is used to acquire the current oil temperature of the refrigeration oil when the preset oil return trigger conditions are met. The control module is used to determine the step-up frequency increase strategy for the compressor to enter the oil return mode when the current oil temperature is less than the preset oil return temperature threshold, and to control the compressor to operate according to the step-up frequency increase strategy, wherein the step-up frequency increase strategy includes the frequency increase step size and the corresponding frequency increase time interval. The triggering module is used to trigger a multi-energy complementary mechanism to introduce auxiliary energy for power compensation when the real-time output power of the solar power supply system is insufficient to maintain the operation of the stepped frequency increase strategy during the process of controlling the compressor to operate according to the stepped frequency increase strategy.

10. An air conditioning system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the oil return control method of the solar air conditioner as described in any one of claims 1 to 8.

Images