Energy-saving control method for inverter compressor
By establishing a multi-dimensional operating condition mapping model based on shutdown duration and heat transfer principles, the frequency of the variable-frequency compressor is dynamically adjusted, which solves the energy waste and temperature control accuracy problems of variable-frequency compressors under different operating conditions in the existing technology, and realizes efficient and energy-saving operation of commercial refrigeration equipment.
Patent Information
- Application Number
- CN202510991423.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-18
- Publication Date
- 2025-10-21
AI Technical Summary
Existing variable-frequency compressor control methods cannot be dynamically adjusted according to actual operating conditions, resulting in insufficient cooling capacity under high-temperature and high-load conditions or excessive cooling under low-temperature and low-load conditions, causing energy waste. In addition, traditional control schemes lack accurate judgment of ambient temperature fluctuations and human operations, affecting the temperature control accuracy and energy efficiency of refrigeration equipment.
By establishing a multi-dimensional working condition mapping model, using the downtime duration of the refrigeration equipment as a characteristic parameter that comprehensively reflects the impact of ambient temperature fluctuations, equipment insulation performance and human operation, combining the principles of heat transfer to calculate the cooling capacity, and dynamically adjusting the frequency of the variable frequency compressor, accurate heat load judgment and adaptive adjustment of the refrigeration equipment can be achieved.
It realizes efficient operation of variable frequency compressor under complex working conditions, reduces energy consumption, improves temperature control accuracy, enhances adaptability to complex environments, reduces ineffective power consumption, and provides an energy-saving operation solution for commercial refrigeration equipment.
Smart Images
Figure CN120819932A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of refrigeration equipment and relates to a variable frequency compressor, in particular to an energy-saving control method for a variable frequency compressor. Background Art
[0002] Currently, there are two main control methods for variable frequency compressors commonly used in commercial refrigeration equipment: mechanical variable frequency and computerized variable frequency. Mechanical variable frequency uses a fixed frequency control strategy and cannot dynamically adjust to actual operating conditions. This results in insufficient cooling capacity under high-temperature and high-load conditions, and excessive cooling capacity under low-temperature and low-load conditions, resulting in energy waste.
[0003] Although computer variable frequency technology has the ability to receive external signals, the existing control scheme still has obvious defects: on the one hand, it only relies on a single temperature sensor signal and cannot distinguish the combined impact of different factors on the temperature of the refrigeration equipment, such as ambient temperature fluctuations, attenuation of the equipment's thermal insulation performance, and human operations (such as frequent door opening). This leads to insufficient control accuracy and limited energy saving effects. On the other hand, there is a lack of accurate modeling of the dynamic heat load characteristics of the refrigeration equipment, resulting in delayed control response or over-adjustment, especially under conditions of sudden changes in ambient temperature or frequent door opening, which often causes frequent starting and stopping of the compressor and additional energy loss.
[0004] In summary, the existing variable-frequency compressor control methods are unable to achieve adaptive adjustment and are difficult to adapt to the differences in characteristics of different refrigeration equipment. Due to the influence of factors such as thermal insulation performance, usage environment and human operation, there are significant differences in the temperature change rates of different equipment. In application scenarios such as commercial cold chains that require high temperature control accuracy, it will directly affect the quality and safety of stored items and significantly increase equipment operating costs. Summary of the Invention
[0005] In order to solve the technical problems existing in the background technology, the present invention proposes an energy-saving control method for a variable-frequency compressor, which integrates multiple factor variables such as ambient temperature, insulation capacity and human operation, takes the downtime duration as a signal and maps it into a closed-loop control mechanism of the compressor frequency, thereby achieving maximum energy saving.
[0006] The purpose of the present invention can be achieved through the following technical solutions: A variable frequency compressor energy-saving control method comprises the following steps: S1, obtaining the minimum cooling capacity of the refrigeration equipment under various preset test conditions; S2, recording the downtime duration of the refrigeration equipment under various test conditions, dividing the downtime ranges of different test conditions, and establishing a mapping relationship between different test conditions and downtime ranges; S3, real-time monitoring of the downtime duration of the refrigeration equipment in the current refrigeration cycle; S4, matching the corresponding test conditions according to the downtime range in which the downtime duration falls, and then determining the required cooling capacity of the refrigeration equipment; S5, outputting a frequency control signal that matches the cooling capacity to the variable frequency compressor.
[0007] Furthermore, in step S1, the preset test conditions include various standard climate test conditions. The minimum cooling capacity of the refrigeration equipment is calculated based on the principles of heat transfer and refrigeration, and the minimum cooling capacity includes a design margin. Specifically, the ambient heat leakage is calculated using the heat transfer coefficient of the refrigeration equipment's enclosure structure. The heat storage load is then calculated using the heat capacity of the cargo within the refrigeration equipment. Finally, the ambient heat leakage and heat storage load are added together, and a design margin of 10%-20% is added to obtain the minimum cooling capacity of the refrigeration equipment.
[0008] Furthermore, recording the downtime duration of the refrigeration equipment in step S2 includes the following steps: S21, setting the shutdown temperature T and the start-stop differential ΔT of the refrigeration equipment; S22, when the temperature inside the refrigeration equipment reaches (T-ΔT), the variable frequency compressor stops and the timing starts. When the temperature inside the refrigeration equipment reaches (T+ΔT), the variable frequency compressor starts again and the timing stops. S23, recording the time interval Δt from when the variable frequency compressor stops to when the variable frequency compressor starts again.
[0009] Furthermore, the shutdown temperature T and the start-stop hysteresis ΔT set in step S21 are constant.
[0010] Furthermore, when dividing the downtime range, first record the downtime duration of the refrigeration equipment under each test condition multiple times to obtain a data set of downtime duration under multiple different test conditions, perform comprehensive statistical analysis on the multiple data sets, obtain the critical value of the downtime duration between different test conditions, and divide the downtime range of different test conditions.
[0011] Furthermore, the refrigeration capacity required by the refrigeration equipment in step S4 adopts the minimum refrigeration capacity of the refrigeration equipment under the same test conditions obtained in step S1.
[0012] Furthermore, outputting a frequency control signal matching the cooling capacity to the variable frequency compressor in step S5 specifically includes the following steps: S51, establishing a correspondence between the cooling capacity of the refrigeration equipment and the operating frequency of the variable frequency compressor according to the operating parameters of the variable frequency compressor; S52, matching the corresponding variable frequency compressor operating frequency according to the required cooling capacity of the refrigeration equipment; S53, retrieve the corresponding frequency control signal and output it to the variable frequency compressor.
[0013] Furthermore, the control method further comprises the steps of: S6 , each time the refrigeration device runs for a preset time, adaptive calibration is performed according to the actual downtime duration distribution of the refrigeration device within the preset time period, and the downtime time range in step S2 is dynamically updated.
[0014] A control system for implementing the control method, comprising: The parameter setting module is used to preset multiple test conditions and the minimum cooling capacity of the refrigeration equipment under each test condition, and to preset the corresponding relationship between the cooling capacity of the refrigeration equipment and the operating frequency of the variable frequency compressor.
[0015] Working condition mapping module, which stores the mapping relationship between various test working conditions and downtime ranges; The signal acquisition module includes a temperature sensor and a time sensor. The temperature sensor continuously monitors the temperature changes in the refrigeration equipment. When it is detected that the temperature reaches the shutdown point, the time sensor starts timing and stops timing when the temperature returns to the startup point, thereby recording the shutdown duration of the refrigeration equipment. The shutdown point is the preset shutdown temperature T minus the start-stop hysteresis ΔT, and the startup point is the preset shutdown temperature T plus the start-stop hysteresis ΔT.
[0016] The processing module matches the corresponding test working condition from the working condition mapping module according to the downtime range of the downtime duration, and then determines the cooling capacity required by the refrigeration equipment; The signal output module outputs a frequency control signal that matches the cooling capacity to the variable frequency compressor.
[0017] A refrigeration device includes the control system and a variable frequency compressor. The variable frequency compressor can receive an external frequency control signal. The frequency control signal is input through the signal receiving port of the frequency conversion board to dynamically adjust the operating frequency of the variable frequency compressor. Beneficial effects of the present invention: The variable frequency compressor energy-saving control method provided by the present invention, by establishing a multi-dimensional working condition mapping model, innovatively uses the downtime duration of the refrigeration equipment as a characteristic parameter that comprehensively reflects the ambient temperature fluctuation, the thermal insulation performance of the equipment and the influence of human operation, overcomes the inherent defect of the traditional single temperature signal control method that cannot distinguish different heat load sources, and realizes the accurate judgment of the actual heat load of the refrigeration equipment by establishing a dynamic association between the standard climate working condition and the downtime range, so that the variable frequency compressor can adjust the operating frequency according to the actual demand, fundamentally solving the energy waste problem caused by the mismatch between the control parameters and the actual working conditions in the prior art, and by adopting a refrigeration method based on the principle of heat transfer The capacity calculation model, combined with the dynamic design margin adjustment mechanism, not only ensures the reliable operation of the refrigeration equipment, but also avoids energy loss caused by over-refrigeration. At the same time, by constructing an intelligent matching algorithm between refrigeration capacity and compressor frequency, the frequency output control with optimal energy efficiency is achieved. In addition, the innovative adaptive calibration function can regularly optimize the working condition discrimination threshold, so that it can automatically adapt to long-term influencing factors such as equipment aging and seasonal changes, and continuously maintain the optimal control state. Compared with traditional control methods, the present invention significantly improves the operating efficiency of the variable frequency compressor under variable working conditions, reduces ineffective power consumption, and enhances the adaptability to complex usage environments, providing an effective technical solution for the energy-saving operation of commercial refrigeration equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 Schematic diagram of the control flow of the present invention. DETAILED DESCRIPTION
[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.
[0020] like Figure 1 As shown, the present invention provides an energy-saving control method for a variable frequency compressor, comprising the following steps: S1, obtaining the minimum cooling capacity of the refrigeration equipment under multiple preset test conditions.
[0021] Among them, the preset test conditions include high temperature and high load conditions, normal temperature and medium load conditions, low temperature and low load conditions and other standard climate type test conditions.
[0022] The minimum cooling capacity of a refrigeration unit is calculated using the principles of heat transfer and refrigeration, and includes a design margin. Specifically, the ambient heat leakage is calculated using the heat transfer coefficient of the unit's enclosure. The thermal storage load is then calculated using the heat capacity of the cargo within the unit. Finally, the ambient heat leakage and thermal storage load are added together, and a 10%-20% design margin is added to determine the minimum cooling capacity of the refrigeration unit.
[0023] S2, respectively recording the downtime duration of the refrigeration equipment under various test conditions, dividing the downtime ranges of different test conditions, and establishing a mapping relationship between different test conditions and downtime ranges.
[0024] The process of recording the downtime duration of the refrigeration equipment includes the following steps: S21, setting the shutdown temperature T and the start-stop hysteresis ΔT of the refrigeration equipment.
[0025] The set shutdown temperature T and the start-stop hysteresis difference ΔT are constant. When the set shutdown temperature T and the start-stop hysteresis difference ΔT are constant, the ambient temperature changes, the insulation capacity, and the manual opening of the door will directly affect the downtime duration of the variable frequency compressor from shutdown to restart. This downtime duration encompasses all external factors. Therefore, the downtime duration Δt is used as a dynamic parameter to comprehensively reflect variables such as the amplitude of ambient temperature fluctuations, the insulation performance of the refrigeration equipment, and the temperature rise of the refrigeration equipment caused by manual door opening. By comparing the external environment with the downtime range, the required cooling capacity can be determined, and the operating frequency of the variable frequency compressor can be adjusted to maximize the effective power.
[0026] S22, when the temperature inside the refrigeration equipment reaches (T-ΔT), the variable frequency compressor stops and starts timing. When the temperature inside the refrigeration equipment reaches (T+ΔT), the variable frequency compressor starts again and stops timing.
[0027] S23, recording the time interval Δt from when the variable frequency compressor stops to when the variable frequency compressor starts again.
[0028] To define downtime ranges, the system first records the downtime duration of the refrigeration equipment under various test conditions multiple times to obtain a dataset of downtime durations under different test conditions. Cluster analysis is then performed on these datasets to determine the critical downtime durations between different test conditions, which are then used to define downtime ranges for each test condition. Specifically, when Δt ≤ t1, it corresponds to a high-temperature, high-load condition; when t1 < Δt ≤ t2, it corresponds to a normal-temperature, medium-load condition; and when Δt > t2, it corresponds to a low-temperature, low-load condition.
[0029] S3 monitors the downtime duration of the refrigeration equipment in the current refrigeration cycle in real time. This is achieved through the collaborative work of temperature sensors and time sensors. The downtime duration comprehensively reflects ambient temperature fluctuations, changes in insulation performance, and human factors.
[0030] S4: Match the corresponding test conditions according to the downtime range of the downtime duration, and then determine the required cooling capacity of the refrigeration equipment. The required cooling capacity of the refrigeration equipment is the minimum cooling capacity of the refrigeration equipment under the same test conditions obtained in step S1.
[0031] S5, outputting a frequency control signal that matches the cooling capacity to the variable frequency compressor.
[0032] Outputting a frequency control signal that matches the cooling capacity to the variable frequency compressor specifically includes the following steps: Step S51, establishing a correspondence between the cooling capacity of the refrigeration equipment and the operating frequency of the variable frequency compressor according to the operating parameters of the variable frequency compressor; Step S52, matching the corresponding variable frequency compressor operating frequency according to the cooling capacity required by the refrigeration equipment; Step S53: Retrieve the corresponding frequency control signal and output it to the variable frequency compressor.
[0033] S6 , each time the refrigeration device runs for a preset time, adaptive calibration is performed according to the actual downtime duration distribution of the refrigeration device within the preset time period, and the downtime time range in step S2 is dynamically updated.
[0034] A variable frequency compressor energy-saving control system, comprising: The parameter setting module is used to preset multiple test conditions and the minimum cooling capacity of the refrigeration equipment under each test condition, and to preset the corresponding relationship between the cooling capacity of the refrigeration equipment and the operating frequency of the variable frequency compressor.
[0035] The working condition mapping module stores the mapping relationship between various test working conditions and downtime ranges.
[0036] The signal acquisition module includes a temperature sensor and a time sensor. The temperature sensor continuously monitors the temperature changes in the refrigeration equipment. When it is detected that the temperature reaches the shutdown point, the time sensor starts timing and stops timing when the temperature returns to the startup point, thereby recording the shutdown duration of the refrigeration equipment. The shutdown point is the preset shutdown temperature T minus the start-stop hysteresis ΔT, and the startup point is the preset shutdown temperature T plus the start-stop hysteresis ΔT.
[0037] The processing module matches the corresponding test working condition from the working condition mapping module according to the downtime range of the downtime duration, and further determines the cooling capacity required by the refrigeration equipment.
[0038] The signal output module outputs a frequency control signal that matches the cooling capacity to the variable frequency compressor.
[0039] A refrigeration device includes the above-mentioned control system and a variable frequency compressor. The variable frequency compressor can receive an external frequency control signal. The frequency control signal is input through the signal receiving port of the frequency conversion board to dynamically adjust the operating frequency of the variable frequency compressor.
[0040] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.
Claims
1. A variable frequency compressor energy-saving control method, characterized in that: The following steps are involved: S1, obtaining the minimum cooling capacity of the refrigeration equipment under various preset test conditions; S2, recording the downtime duration of the refrigeration equipment under various test conditions, dividing the downtime ranges of different test conditions, and establishing a mapping relationship between different test conditions and downtime ranges; S3, real-time monitoring of the downtime duration of the refrigeration equipment in the current refrigeration cycle; S4, matching the corresponding test conditions according to the downtime range in which the downtime duration falls, and then determining the required cooling capacity of the refrigeration equipment; S5, outputting a frequency control signal that matches the cooling capacity to the variable frequency compressor.
2. The control method according to claim 1, characterized in that: In step S1, the preset test conditions include a variety of standard climate type test conditions, and the minimum cooling capacity of the refrigeration equipment is calculated based on the principles of heat transfer and refrigeration, and the minimum cooling capacity includes a design margin.
3. The control method according to claim 1, wherein: Recording the downtime duration of the refrigeration equipment in step S2 includes the following steps: S21, setting the shutdown temperature T and the start-stop differential ΔT of the refrigeration equipment; S22, when the temperature inside the refrigeration equipment reaches (T-ΔT), the variable frequency compressor stops and the timing starts. When the temperature inside the refrigeration equipment reaches (T+ΔT), the variable frequency compressor starts again and the timing stops. S23, recording the time interval Δt from when the variable frequency compressor stops to when the variable frequency compressor starts again.
4. The control method according to claim 3, characterized in that: The shutdown temperature T and the start-stop hysteresis ΔT set in step S21 are constant.
5. The control method according to claim 1, characterized in that: When dividing the downtime range, we first record the downtime duration of the refrigeration equipment under each test condition multiple times to obtain a data set of downtime duration under multiple different test conditions. We then perform a comprehensive statistical analysis on the multiple data sets to obtain the critical value of the downtime duration between different test conditions and divide the downtime range of different test conditions.
6. The control method according to claim 1, characterized in that: The cooling capacity required by the refrigeration equipment in step S4 adopts the minimum cooling capacity of the refrigeration equipment under the same test conditions obtained in step S1.
7. The control method according to claim 1, characterized in that: Outputting a frequency control signal that matches the cooling capacity to the variable frequency compressor in step S5 specifically includes the following steps: S51, establishing a correspondence between the cooling capacity of the refrigeration equipment and the operating frequency of the variable frequency compressor according to the operating parameters of the variable frequency compressor; S52, matching the corresponding variable frequency compressor operating frequency according to the required cooling capacity of the refrigeration equipment; S53, retrieve the corresponding frequency control signal and output it to the variable frequency compressor.
8. The control method according to claim 1, characterized in that: Also includes the steps: S6 , each time the refrigeration device runs for a preset time, adaptive calibration is performed according to the actual downtime duration distribution of the refrigeration device within the preset time period, and the downtime time range in step S2 is dynamically updated.
9. A control system implementing any one of the control methods of claims 1 to 8, characterized in that: include: A parameter setting module is used to preset multiple test conditions and the minimum cooling capacity of the refrigeration equipment under each test condition, and to preset the corresponding relationship between the cooling capacity of the refrigeration equipment and the operating frequency of the variable frequency compressor; Working condition mapping module, which stores the mapping relationship between various test working conditions and downtime ranges; The signal acquisition module includes a temperature sensor and a time sensor. The temperature sensor continuously monitors the temperature changes in the refrigeration equipment. When the temperature reaches the shutdown point, the time sensor starts timing and stops timing when the temperature returns to the startup point, thus recording the shutdown duration of the refrigeration equipment. The processing module matches the corresponding test working condition from the working condition mapping module according to the downtime range of the downtime duration, and then determines the cooling capacity required by the refrigeration equipment; The signal output module outputs a frequency control signal that matches the cooling capacity to the variable frequency compressor.
10. A refrigeration device comprising the control system according to claim 9 and a variable frequency compressor, characterized in that: The variable frequency compressor can receive an external frequency control signal, and the frequency control signal is input through the signal receiving port of the frequency conversion board to dynamically adjust the operating frequency of the variable frequency compressor.