Constant-frequency compressor group control energy regulation system based on outdoor temperature and humidity coupling

Abstract

The invention relates to the technical field of refrigeration air conditioners and automatic control, in particular to a fixed frequency compressor group control energy regulation system based on outdoor temperature and humidity coupling, which comprises a data acquisition unit, a reheating demand judgment unit and an anti-icing protection control unit, a data acquisition unit acquires outdoor temperature and humidity coupling data and return air temperature data of all compressors through an outdoor temperature and humidity sensor and a return air temperature sensor, and a reheating demand judgment unit implements temperature feedforward control based on outdoor temperature and humidity and sets an adjustable limit level to constrain the input proportion of the compressors. When the compressors are fully input and the humidity exceeds the standard, the moisture content of indoor, target and outdoor air is calculated, the reheating requirement is judged by combining the transient temperature when the integral speed of the cooling and dehumidification PID controller and the adjustable limiting level and the floating gear are adjusted according to the moisture content, and the anti-icing protection control unit periodically monitors the return air temperature and takes measures. The problems that temperature and humidity control of a traditional system is not coordinated, and anti-icing protection is not accurate are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration air conditioning and automatic control, in particular to a group control energy regulation system of fixed frequency compressor based on outdoor temperature and humidity coupling. BACKGROUND

[0002] Refrigeration air conditioning and automatic control is an important technology, under the background of current building energy saving and comfort demand double promotion, this technology is the key support to ensure the stable operation of large air conditioning system, which can not only avoid the energy loss caused by frequent start and stop of single fixed frequency compressor, but also improve the overall operation efficiency by group control and reasonable load distribution, and can accurately match the indoor temperature and humidity demand, prevent excessive refrigeration or insufficient dehumidification, avoid compressor back gas pipe icing and liquid knock fault, prolong the service life of equipment, and adapt to the scene of commercial complex, data center and high requirement of air conditioning system reliability and energy efficiency; The existing fixed frequency compressor group control system faces the core problems of uncoordinated temperature and humidity control and inaccurate anti-icing protection in actual application. The traditional system mainly sets the compressor input proportion according to the outdoor temperature, without considering the influence of temperature and humidity coupling on air humidity. When the outdoor humidity is high, the compressor input proportion set according to the temperature often cannot meet the dehumidification demand, resulting in continuous over-standard indoor humidity, which needs to start the reheating device for adjustment in the later period, increasing energy consumption and destroying the balance of temperature and humidity. At the same time, the anti-icing protection mainly uses a unified back gas temperature threshold and fixed monitoring period, without setting independent protection standards according to the model and running time difference of each compressor, and without dynamically adjusting the scanning frequency according to the number of running compressors. This defect will cause the temperature and humidity control to be out of sync, resulting in a decrease in indoor comfort, and energy waste caused by additional reheating. In addition, the unified threshold is easy to trigger protection for old compressors and delay protection for new compressors, causing some compressor back gas pipes to freeze and block the pipeline, affecting system cooling capacity. When the number of running compressors increases, the fixed monitoring period cannot timely detect temperature abnormalities of multiple compressors, expanding the risk of failure and even causing compressor liquid knock damage, increasing maintenance cost and system downtime. In the long run, it is difficult to balance indoor comfort demand and energy saving goal, and it is also difficult to ensure the long-term stable operation of compressor cluster. In order to solve this technical problem, we provide a group control energy regulation system of fixed frequency compressor based on outdoor temperature and humidity coupling. SUMMARY

[0003] The purpose of the present application is to provide a group control energy regulation system of fixed frequency compressor based on outdoor temperature and humidity coupling to solve the problems raised in the background technology, Since the compressor input proportion is set only according to the outdoor temperature, without considering the dehumidification caused by temperature and humidity coupling and the energy consumption caused by additional reheating, the present case can adapt to the dehumidification demand and reduce energy consumption by adjusting the energy regulation limit level and the cooling and dehumidification PID integral speed based on the outdoor temperature and humidity to calculate the humidity content through the reheating demand judgment unit.

[0004] Due to the unified threshold and fixed period of anti-icing protection, the protection is not accurate and the risk of failure is high, therefore, the case through the anti-icing protection unit sets independent early warning / protection threshold, according to the adjustable limit level and the number of running machines to adjust the monitoring period, which can accurately prevent icing and reduce the failure probability of the compressor.

[0005] In order to achieve the above object, a group control energy regulation system of fixed frequency compressor based on outdoor temperature and humidity coupling is provided, comprising; The data acquisition unit collects outdoor temperature and humidity data and return air temperature data of each compressor through outdoor temperature and humidity sensors and return air temperature sensors; The reheating demand judgment unit performs first step temperature feedforward control based on outdoor temperature and humidity data, sets the adjustable limit level to preliminarily constrain the compressor input proportion, continuously monitors the running time when all the compressors are running, and evaluates whether the sampled temperature and humidity is within the set deviation range when the running time reaches the set value. When the humidity sampling value is higher than the upper limit of the set deviation, the air moisture content state of the indoor sampling point, the set point and the outdoor working condition point is calculated, and whether to adjust the integral action speed of the cooling and dehumidification PID controller and the adjustable limit level is judged by comparing the air moisture content state. When the adjustable limit level is up, the transient temperature value is combined to judge the reheating demand; The anti-icing protection control unit periodically monitors the return air temperature of each compressor and compares it with the preset early warning value and protection value, starts the compressor rotation operation when the return air temperature is lower than the early warning value, and immediately stops the compressor and starts two other compressors to supplement energy when the return air temperature drops to the protection value. After that, optimize the shutdown to realize energy balance. When the adjustable limit level is raised, the anti-icing monitoring period is adjusted according to the number of open compressors, the scanning frequency is reduced to speed up the rotation and reduce the risk of icing.

[0006] Compared with the prior art, the beneficial effects of the present application are: The reheating demand judgment unit calculates the indoor, target and outdoor air moisture content based on the outdoor temperature and humidity data, dynamically adjusts the adjustable limit level and the integral action speed of the cooling and dehumidification PID controller, and the anti-icing protection unit sets independent return air temperature early warning / protection threshold for each compressor and adjusts the anti-icing monitoring period combined with the adjustable limit level and the number of running compressors. At the same time, the two-way coupling of the reheating demand judgment unit and the anti-icing protection unit is realized, which achieves the technical effects of accurate matching of compressor input proportion and temperature and humidity coupling demand, accurate identification and timely response of icing risk, and collaborative optimization of temperature and humidity control and anti-icing protection. It effectively solves the problems of incoordination of temperature and humidity control and inaccuracy of anti-icing protection in the group control system of fixed frequency compressor, and guarantees the efficient operation of the system and the long-term stability of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 It is the overall block diagram of the present application. The significance of each reference numeral in the figure is as follows: 1, data acquisition unit; 2, reheat demand judgment unit; 3, anti-icing protection control unit. DETAILED DESCRIPTION

[0008] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application, The present application provides a group control energy modulation system of a fixed-frequency compressor based on outdoor temperature and humidity coupling. Please refer to Figure 1 As shown in the figure, it comprises: The data acquisition unit 1 acquires outdoor temperature and humidity data and return air temperature data of each compressor through outdoor temperature and humidity sensors and return air temperature sensors; The reheat demand judgment unit 2 performs first-step temperature feedforward control based on outdoor temperature and humidity data, sets an energy modulation limit level to preliminarily constrain the proportion of compressor input, continuously monitors the running time when all the compressors are running, evaluates whether the sampled temperature and humidity is within the set deviation range when the running time reaches the set value, calculates the air moisture content state of the indoor sampling point, the set point and the outdoor working condition point when the humidity sampling value is higher than the upper limit of the set deviation, and judges whether to adjust the integral action speed of the cooling and dehumidification PID controller and the energy modulation limit level by comparing the air moisture content state, wherein the reheat demand is judged in combination with the transient temperature value when the energy modulation limit level is floated to the next position; The anti-icing protection control unit 3 compares the return air temperature of each compressor with the preset warning value and protection value by periodic monitoring, starts the compressor rotation operation when the return air temperature is lower than the warning value, immediately stops the compressor and starts two other compressors to supplement energy when the return air temperature drops to the protection value, and then optimizes the shutdown to realize energy balance, adjusts the anti-icing monitoring cycle length according to the number of opened compressors when the energy modulation limit level is raised to the next position, reduces the scanning frequency to accelerate rotation and reduce the risk of icing, The data acquisition unit 1 realizes outdoor temperature and humidity coupling data acquisition through outdoor temperature and humidity sensors, and acquires return air temperature data of each compressor through a return air temperature sensor independently installed on the return air pipe of each fixed-frequency compressor. The return air temperature sensor is located at the pipe section position where the refrigerant flows out of the surface cooler in the corresponding compressor circuit, The first-step temperature feedforward control performed by the reheat demand judgment unit 2 adopts an energy modulation limit level strategy, which specifically comprises: The adjustable limit level strategy divides several temperature intervals according to the outdoor temperature and sets the upper limit value of the maximum input proportion of the compressor, when all the compressors used for calculation are running and the continuous running time reaches the set time length, and the humidity sampling value is continuously higher than the set upper limit of deviation, the moisture content state calculation mechanism is triggered, The implementation of the moisture content state calculation mechanism specifically includes: The current air moisture content state value is calculated based on the indoor temperature and humidity sampling values, the target moisture content state value is calculated based on the set temperature and humidity values, and the outdoor moisture content state value is calculated based on the outdoor temperature and humidity values; The PID control parameter adjustment direction is determined by the comparison relationship of the three groups of moisture content states: When the indoor moisture content state value does not exceed the target value, the original cooling and dehumidifying demand is maintained, but the reheat PID integral action is accelerated, when the indoor moisture content state value exceeds the target value and the outdoor moisture content state value is better than the target value, the cooling and dehumidifying PID integral action is enhanced and the reheat demand is evaluated, and when the outdoor moisture content state value is worse than the target value, the adjustable limit level is raised and the cooling and dehumidifying PID integral action is suppressed, The implementation of the adjustable limit level raising operation specifically includes: When it is determined that the outdoor moisture content state value is worse than the target value, the current adjustable limit level is raised to the adjacent high level, which is used to break through the original proportion upper limit constraint of the first step temperature feedforward control, The anti-icing protection control unit 3 sets independent return air temperature warning thresholds and protection thresholds for each compressor, and performs cyclic scanning on the return air pipe temperature of all running compressors based on the preset anti-icing monitoring period; When it is detected that the return air temperature of a compressor is lower than the warning threshold but higher than the protection threshold, the compressor rotation operation is started, that is, according to the layout relationship of the table cooler pipeline, the standby compressor farthest from the physical position of the compressor is started, and after the new compressor runs stably, the original compressor in the warning state is closed, When it is detected that the return air temperature of a compressor is lower than the protection threshold, the compressor is immediately closed and two preset associated compressors are simultaneously started, after the two newly started compressors run continuously for a minimum protection running time, the one with the lowest temperature is closed according to the real-time return air temperature data to achieve system energy balance, The time length adjustment mechanism of the anti-icing monitoring period specifically includes: when the adjustable limit level is raised, if more than half of the running compressors have return air temperatures lower than the warning threshold, the original anti-icing monitoring period is shortened to the quotient of the original time length divided by the number of running compressors, and the scanning interval is shortened to accelerate the compressor rotation frequency, The compressor rotation operation relies on the distance parameter preset by the layout of the surface condenser pipeline to realize, and the residual cold complementary effect is formed by the cold transfer time difference between the newly started compressor and the stopped compressor in the rotation process, which reduces the icing risk and maintains the stability of the total cold output of the system, The reheating demand judgment unit 2 and the anti-icing protection control unit 3 form a two-way coupling, specifically including: The adjustable restriction level change triggers the anti-icing monitoring period adjustment, and the compressor rotation state is fed back to the reheating PID calculation module in real time, and the temperature and humidity control and the anti-freezing protection are cooperatively optimized through two-way data interaction, It needs to be further explained that in the adjustable frequency compressor group control system based on outdoor temperature and humidity coupling, the data acquisition unit 1 is the basis for realizing accurate control and protection, and all subsequent reheating demand judgment and anti-icing protection operations rely on the real working condition data collected by it, so the accuracy and real-time performance of the temperature and humidity and return air temperature data need to be ensured through professional sensor deployment and data acquisition logic, and the specific implementation is as follows: The data acquisition unit 1 realizes outdoor temperature and humidity coupling data acquisition through outdoor temperature and humidity sensors. The outdoor temperature and humidity coupling data here refers to the simultaneously collected outdoor temperature and relative humidity data. The two are not independent, but together determine the air moisture content (affecting the dehumidification demand) and the refrigeration load (affecting the compressor input ratio), and need to be analyzed cooperatively to reflect the real outdoor working condition. As for sensor selection, the temperature sensor uses a high-precision platinum resistance sensor that can adapt to outdoor temperature changes in different seasons. The humidity sensor uses a capacitive sensor that can accurately capture humidity fluctuations in high-humidity or low-humidity environments. The installation location needs to meet the non-interference principle, that is, the sensor is fixed in an outdoor louver box with good ventilation, avoiding direct sunlight, high temperature, rain splashing, humidity misjudgment, air conditioner outdoor unit heat source, and local temperature anomalies, while ensuring that the sensor air inlet is not blocked and can contact outdoor air in real time. The collection frequency is set to once every 10 seconds. The data is transmitted to the system main controller through the 485 industrial bus. CRC cyclic redundancy check is performed during transmission to prevent data loss or tampering and ensure that each set of temperature and humidity data can truly reflect the real-time outdoor working condition. At the same time, the return air temperature data of each compressor is collected by a return air temperature sensor installed independently on the return air pipe of each adjustable frequency compressor. The return air temperature refers to the temperature of the refrigerant after flowing out of the surface condenser and before returning to the compressor. This temperature is directly related to the refrigerant superheat. If the temperature is too low, it means that the refrigerant may be liquid, which can cause the return air pipe to freeze or the compressor to be damaged by liquid strike. Therefore, each compressor needs to be monitored independently. The sensor uses armored K-type thermocouples that are resistant to refrigerant corrosion and have good thermal conductivity, which can accurately capture small changes in return air temperature. Independent installation is the core technical feature: The return gas pipeline of each fixed-frequency compressor is an independent circuit, and the return gas temperature is affected by its own load and refrigerant flow. If a shared sensor is used, cross interference will occur, and if the return gas temperature of a certain compressor is low, it cannot be located. Therefore, a sensor mounting seat needs to be drilled and welded on the return gas pipe of each compressor, the sensor probe is inserted into the pipeline by 3-5 mm to ensure direct contact with the refrigerant, the outside is fixed with a nut, the interface is wrapped with sealing tape to prevent refrigerant leakage, the sensor cable is protected by a metal corrugated pipe to avoid damage caused by compressor vibration, and the return gas temperature sensor is located in the pipe section where the refrigerant flows out of the surface cooler in the corresponding compressor circuit. The selection of this position is the key to ensuring the accuracy of measurement. After the refrigerant flows out of the surface cooler, it has not yet entered the compressor suction chamber, and the temperature has not been affected by the heat dissipation of the compressor. It can truly reflect the heat exchange effect of the surface cooler and the state of the refrigerant. If it is installed near the compressor suction port, the temperature will be higher due to the heat dissipation of the compressor motor, which will lead to a false judgment of the return gas temperature. The specific position is defined as a straight pipe section 15-20 cm away from the refrigerant outlet flange of the surface cooler. There are no valves, bends, and other components in this area to avoid local turbulence that can cause uneven temperature distribution. The temperature distribution is uniform. After installation, calibration is required. During system debugging, use a standard thermometer to compare the sensor reading by tightly attaching the thermometer to the outer wall of the pipeline at the sensor installation position. If the deviation exceeds 0.5°C, adjust the sensor insertion depth or perform linear calibration through software to ensure that the return gas temperature data error of each compressor is controlled within the allowed range, providing a reliable basis for subsequent ice protection. The specific implementation of the first step temperature feedforward control of the reheating demand judgment unit 2 The first temperature feedforward control performed by the reheating demand judging unit 2 adopts an adjustable limit level strategy. The temperature feedforward control refers to adjusting the control quantity in advance according to the outdoor temperature as a disturbance factor, instead of depending on the indoor temperature and humidity deviation. For example, the compressor input proportion is increased in advance when the outdoor temperature is high in summer, and the input proportion is reduced when the outdoor temperature is low in winter, so as to reduce the temperature and humidity fluctuation from the source. The adjustable limit level strategy divides the outdoor temperature into several intervals, each interval corresponds to an upper limit of the maximum input proportion of the compressor, forming a corresponding relationship between the temperature and the input proportion, so as to prevent the compressor from over-input or under-input. The adjustable limit level strategy divides the outdoor temperature into several temperature intervals and sets the upper limit of the maximum input proportion of the compressor corresponding to each temperature interval. The temperature interval division needs to be combined with the actual refrigeration load characteristics: 5℃ is taken as an interval, and five core intervals of ≤10℃, 10℃-15℃, 15℃-20℃, 20℃-25℃ and >25℃ are divided. The input proportion of each interval is calibrated based on historical operation data. When the outdoor temperature is ≤10℃, the indoor refrigeration demand is weak, and the maximum input proportion is set to 30% (for example, 3 out of 10 compressors are started). When the outdoor temperature is 10℃-15℃, the maximum input proportion is 50% (for example, 5 out of 10 compressors are started). When the outdoor temperature is 15℃-20℃, the maximum input proportion is 70% (for example, 7 out of 10 compressors are started). When the outdoor temperature is 20℃-25℃, the maximum input proportion is 90% (for example, 9 out of 10 compressors are started). When the outdoor temperature is >25℃, the maximum input proportion is 100% (all compressors are allowed to be started). The logic of setting the proportion is that the input proportion is increased by 20% or 10% when the temperature increases by 5℃, so as to ensure that the input proportion increases synchronously with the refrigeration load. When the system is running, the outdoor temperature data is read in real time, the current interval is determined by the temperature interval judgment module, the corresponding maximum input proportion is automatically retrieved, and the number of compressors started is constrained. For example, when the outdoor temperature is 22℃ (belongs to the 20℃-25℃ interval), there are 10 compressors in the system, and 9 compressors are allowed to be started at most, so as to avoid that all the 10 compressors are started to cause excessive cooling capacity. When all the compressors used for calculation are started and run continuously for a set time, the compressors used for calculation refer to all normal fixed-frequency compressors participating in group control in the system, excluding compressors in fault, maintenance or standby states. When all the compressors used for calculation are started, it means that the number of compressors started at present reaches the maximum input proportion of the temperature interval, which indicates that the current input proportion has reached the upper limit, and it is further needed to judge whether the dehumidification demand is met. The set time is set to 15 minutes, because it takes 15 minutes for the compressor to reach stable cooling capacity output after being started. If the humidity condition is judged immediately after the compressor is started, it is easy to cause misjudgment due to insufficient transient cooling capacity. The system records the starting time of the last compressor by a timer, starts timing from the time point, and triggers the humidity sample value evaluation process after 15 minutes. When the humidity sample value continuously exceeds the set upper limit of the deviation, the humidity sample value refers to the average relative humidity of multiple sampling points in the personnel activity area, which are arranged at a density of 50 square meters each, avoiding air outlets and heat sources, so as to ensure that the sample value represents the overall indoor working condition. The set upper limit of the deviation is the target indoor humidity plus the allowed deviation. For example, the target humidity is 50%RH, and the allowed deviation is 5%RH, so the upper limit of the deviation is 55%RH.When the average humidity value defined as the average of three consecutive (each interval of 1 minute) collected values exceeds the upper limit of the deviation, the single humidity fluctuation is avoided to trigger the false operation. The system calculates the indoor average humidity every 1 minute, compares it with the upper limit of the deviation, and when the value exceeds the limit for three consecutive times, it indicates that the indoor humidity is indeed too high, and further analysis of the moisture content is needed to determine the dehumidification direction, which triggers the moisture content state calculation mechanism. The moisture content state calculation mechanism is the key to breaking through the limitation of relative humidity. Relative humidity is greatly affected by temperature (at the same relative humidity, the higher the temperature, the higher the moisture content), while the moisture content (unit g / kg dry air) can directly reflect the water content in the air, and is more suitable as the basis for dehumidification control. After triggering, the system automatically retrieves the indoor temperature and humidity sampling values from the data acquisition unit 1, the target temperature and humidity values from the user setting module, and the outdoor temperature and humidity values from the outdoor temperature and humidity acquisition module, to prepare the basic data for the subsequent three groups of moisture content calculation, ensuring the accuracy of the subsequent PID parameter adjustment direction. The specific implementation of the moisture content state calculation mechanism is as follows: When the reheat demand judgment unit 2 detects that the humidity continues to exceed the standard and triggers the moisture content state calculation mechanism, the indoor, target and outdoor three groups of moisture content state values need to be accurately calculated to objectively judge the deviation direction of the current temperature and humidity control. Relative humidity is easily disturbed by temperature, while moisture content can directly reflect the absolute water content in the air. Therefore, the comparison and analysis based on moisture content can provide a more reliable basis for PID control parameter adjustment, avoiding the dehumidification misjudgment caused by temperature fluctuations. The specific implementation is as follows: The current air moisture content state value is calculated based on indoor temperature and humidity sampling values. The indoor temperature and humidity sampling values are average data collected by indoor distributed humidity sensors. The sensors are arranged in different functional areas of the indoor space, with at least one sensor per 50 square meters. The collection frequency is 1 minute per time. After collection, the overall indoor temperature and humidity are calculated by the arithmetic mean method (average temperature 25°C, average relative humidity 60%RH). The moisture content calculation relies on the temperature-saturated moisture content correlation. First, the saturated vapor pressure table is queried based on the average indoor temperature to obtain the saturated moisture content at that temperature (saturated moisture content at 25°C is about 20.37 g / kg dry air). Then, the indoor average relative humidity is multiplied by the saturated moisture content to obtain the current air moisture content (20.37 x 60% ≈ 12.22 g / kg dry air). To reduce the impact of local deviations, the system automatically removes outliers in the collected data (such as values deviating from the average by ±5%). This ensures that the calculated current moisture content accurately reflects the indoor moisture conditions. The target moisture content state value is calculated based on the set temperature and humidity values. The set temperature and humidity values are the indoor comfort temperature and humidity standards set by the system or customized by the user. Typically, they are divided by season: summer set temperature 24°C~26°C, relative humidity 45%~55%; winter set temperature 20°C~22°C, relative humidity 40%~50% (default set to 24°C, 50%RH). The calculation logic of the target moisture content is consistent with that of the current moisture content. First, the saturated moisture content corresponding to the set temperature is queried (about 19.25 g / kg dry air at 24°C). Then, the set relative humidity is multiplied by the target moisture content (19.25 x 50% ≈ 9.63 g / kg dry air). The system supports modifying the set values through the human-machine interface. After modification, the target moisture content is automatically recalculated and updated to the PID control module, ensuring that the target value matches the user's needs. The outdoor moisture content state value is calculated based on outdoor temperature and humidity values. The outdoor temperature and humidity values are real-time average data collected by data acquisition unit 1 (e.g., temperature 30°C, relative humidity 70%RH). The calculation of the outdoor moisture content also relies on the saturated moisture content query. At 30°C, the saturated moisture content is about 27.78 g / kg dry air. Multiplying by the outdoor relative humidity gives the outdoor moisture content (27.78 x 70% ≈ 19.45 g / kg dry air). The core function of the outdoor moisture content is to judge the dehumidification assistance capacity of outdoor air. If the outdoor moisture content is low (e.g., outdoor -5°C, 50%RH, moisture content about 1.5g / kg), the compressor load can be reduced by introducing fresh air to assist indoor dehumidification, if the outdoor humidity content is high (such as 30℃, 70%RH in summer), the compressor dehumidification is completely dependent, and the introduction of fresh air increases the indoor humidity, the PID control parameter adjustment direction is determined by the comparison of the three groups of humidity content, the PID control parameter mainly refers to the integral action speed of the cooling and dehumidification PID controller (integral coefficient), the integral action directly affects the response speed of the dehumidification effect, the integral coefficient is large, the dehumidification response is fast, and the integral coefficient is small, the response is slow, which needs to be dynamically adjusted according to the comparison result of the humidity content, and the dehumidification efficiency and temperature control are balanced, when the indoor humidity state value does not exceed the target value, the original cooling and dehumidification demand is maintained, but the reheat PID integral action is accelerated, the current humidity is less than or equal to the target humidity (such as 12.22g / kg≤12.5g / kg), which indicates that the current humidity meets the demand, but the continuous operation of the compressor may cause the indoor temperature to drop (such as from 24℃ to 22℃), at this time, the original cooling and dehumidification demand is maintained, that is, the current compressor input proportion and the proportion (P) and differential (D) parameters of the cooling and dehumidification PID are kept unchanged, to avoid excessive adjustment leading to humidity rebound, the reheat PID integral action is accelerated, that is, the integral coefficient of the reheat PID controller is increased (such as from 0.5 to 0.8), so that the reheat device (such as electric heater, hot water coil) can respond to temperature deviation more quickly, when the indoor temperature is lower than the set value by more than 1℃, the reheat device can start quickly to supplement heat to prevent the temperature from being too low, while not affecting the current dehumidification effect, when the indoor humidity state value exceeds the target value and the outdoor humidity state value is better than the target value, the cooling and dehumidification PID integral action is enhanced and the reheat demand is evaluated, the indoor humidity exceeds the target value (such as 12.22g / kg>9.63g / kg), which indicates that the humidity is out of standard, the dehumidification needs to be enhanced, the outdoor air is dry, which can be dehumidified by introducing fresh air, at this time, the integral coefficient of the cooling and dehumidification PID is increased from 0.3 to 0.6, so that the PID controller can accumulate humidity deviation more quickly, and output a larger control signal (such as prolonging the running time of the compressor, starting the standby compressor), to accelerate dehumidification, and the reheat demand is evaluated, that is, the indoor temperature is monitored simultaneously: if the temperature drops by more than 1℃ during dehumidification (such as from 24℃ to below 23℃), the reheat PID control is started, and the reheat device is started moderately to avoid the contradiction that dehumidification is too much and the temperature is too low, and to ensure that the temperature and humidity meet the standard at the same time, when the outdoor humidity state value is worse than the target value, the adjustable limit level is floated and the cooling and dehumidification PID integral action is inhibited, the outdoor humidity is worse than the target value (such as 19.45g / kg>9.63g / kg) indicates that the outdoor air is humid, and introducing fresh air will increase the indoor humidity, which needs to rely entirely on the compressor dehumidification, and the original adjustable limit level may not meet the demand (such as the original level allows 90% to be put in, and the dehumidification capacity is insufficient), and the floating adjustable limit level increases the maximum input proportion of the compressor (such as from 90% to 100%), allows more compressor input, enhances the dehumidification capacity, and the integral action of the dehumidification PID is to reduce the integral coefficient from 0.3 to 0.1, to avoid excessive integral to cause the compressor to start and stop frequently, and to prevent the dehumidification from being too fast to cause the temperature to be too low, to balance the dehumidification speed and the temperature stability by slow integral, to ensure that the indoor temperature fluctuation is controlled within ±0.5℃ while effectively dehumidifying, and the specific implementation of the floating operation of the adjustable limit level is in the comparison of the humidity content state, when it is determined that the outdoor humidity content is worse than the target value, it indicates that the outdoor air is humid, and the original temperature feedforward control set adjustable limit level cannot meet the indoor dehumidification demand, at this time, if the original proportion of the compressor input is continued to be constrained, it will lead to insufficient dehumidification capacity, and the indoor humidity continues to exceed the standard, therefore, the original proportion constraint needs to be broken through by the floating operation of the level, to ensure that the compressor can provide enough cold energy for dehumidification, and at the same time, the stability of the temperature control is considered, and the specific implementation is as follows: When the outdoor humidity content state value is determined to be worse than the target value, the system compares the calculated outdoor humidity content (O) with the target humidity content (T) based on a clear quantitative standard. If the difference between the two exceeds 2 g / kg of dry air (2 g / kg is set as the determination threshold to avoid frequent triggering of upward adjustment due to minor deviations), it is determined that the outdoor humidity content is worse than the target value. For example, if the target humidity content T = 9.63 g / kg and the outdoor humidity content O = 19.45 g / kg, the difference is 9.82 g / kg, which is greater than 2 g / kg, satisfying the upward adjustment triggering condition. If the difference is less than or equal to 2 g / kg (e.g., O = 11.5 g / kg and T = 9.63 g / kg, with a difference of 1.87 g / kg), it is determined that the outdoor humidity content is close to the target value, and no upward adjustment is performed to avoid system fluctuations caused by frequent adjustments. The determination period is set to every 5 minutes, and the system will recalculate the difference between the outdoor humidity content and the target value. If the difference is determined to be worse than the target value for two consecutive times, and the indoor humidity content has exceeded the target value, the gear upward adjustment operation is triggered. If the indoor humidity content is still lower than the target value, it indicates that the current dehumidification is sufficient, and no upward adjustment is performed. The current energy adjustment limit level is increased to the adjacent higher level, and the energy adjustment limit level is a hierarchical system based on the maximum compressor input ratio. It is usually divided into 5 levels: level 1 corresponds to 30% input (up to 30% of the compressor is started), level 2 corresponds to 50%, level 3 corresponds to 70%, level 4 corresponds to 90%, and level 5 corresponds to 100% (full input). The input ratio of adjacent levels differs by 20% or 10%, ensuring a reasonable adjustment range. The adjacent higher level is one level higher than the current level. For example, if the current energy adjustment limit level is 4 (90% input), it will be adjusted to level 5 (100% input) after upward adjustment.If the current is already at the highest level 5 (100% input), it remains unchanged, and a prompt signal is sent out on the system interface that the maximum dehumidification capacity has been reached, informing the operation and maintenance personnel that there is no room for further adjustment, and whether there is any other dehumidification bottleneck needs to be checked (such as the scaling of the cooling coil, the lack of refrigerant), after the gear adjustment, the system will record the adjustment time, the level before and after the adjustment, and the outdoor humidity content data in real time, and store them into the operation log, which is convenient for subsequent operation and maintenance analysis (such as tracing the reason for high load operation in a certain period), and is used to break through the original upper limit constraint of the first step temperature feedforward control, the original upper limit of the first step temperature feedforward control refers to the maximum input ratio set according to the outdoor temperature (such as the outdoor temperature 22℃ belongs to the interval of 20℃~25℃, the original upper limit is level 4 (90% input)), which is set based on the temperature alone, without considering the influence of outdoor humidity, after breaking through the constraint, the maximum input ratio of the compressor is no longer limited by the original temperature interval, for example, the outdoor temperature 22℃ (the original upper limit is 90%), after floating up, it can allow 100% input, so that more compressors participate in operation, and the dehumidification capacity is enhanced, after breaking through the constraint, it is not unlimited operation, the system will set a safety boundary at the same time: one is the upper limit of the continuous operation time of the compressor (set to 4 hours), after exceeding, it is forced to rotate 1 compressor to stop for 15 minutes, to prevent the compressor from overheating and being damaged due to long-term high load operation, the second is the indoor temperature protection: if the indoor temperature drops by more than 2℃ (such as from 24℃ to below 22℃) after floating up, it will automatically reduce the load of part of the compressors (such as reducing the refrigerant flow), rather than continuing to maintain 100% input, to balance dehumidification and temperature control, at the same time, after the gear is floated up, the working condition change needs to be continuously monitored: every 10 minutes, the difference between the outdoor humidity content and the target value is recalculated, if the difference is reduced to within 2g / kg, and the indoor humidity content is lower than the target value, it means that the outdoor working condition has improved, and the dehumidification demand has decreased, at this time, the system will automatically reduce the adjustable limit level to the original gear (such as from level 5 to level 4), to avoid the waste of energy caused by the over-input of the compressor, the reduction process also needs to be gradual: first reduce the input ratio from 100% to 95%, maintain for 5 minutes, if the indoor temperature and humidity are stable, then reduce to 90%, to ensure that the system cold output transitions smoothly without obvious fluctuations, through this kind of dynamic adjustment of floating up according to demand and timely reduction, both the dehumidification demand in high humidity working condition and the energy saving after the working condition improves can be met, to achieve the balance of energy efficiency and comfort, the specific implementation of the anti-icing protection control unit 3 warning and rotation operation is as follows: The anti-icing protection control unit 3 sets independent return air temperature warning thresholds and protection thresholds for each compressor. The independent thresholds are the core design. The models, refrigeration capacity, and running time of each compressor are different, and the anti-icing and liquid strike capabilities are different. If the thresholds are uniformly set, the protection will not be accurate. The thresholds should be set in combination with two aspects: one is the technical manual provided by the compressor manufacturer, and the other is the actual operation data. The warning threshold and the protection threshold of the compressor with a running time of more than 3 years are each increased by 1°C, such as from 5°C and 2°C to 6°C and 3°C. Because the air valve sealing performance of the old compressor decreases, the risk of liquid in the return air is higher. The threshold storage adopts the compressor number-threshold association method: The number of each compressor and the corresponding warning and protection thresholds are stored in the database of the system controller. When called, the thresholds are accurately retrieved by the compressor number to avoid confusion. The system needs to calibrate the thresholds before each season every year. The accuracy of threshold triggering is verified by simulating the change of return air temperature. If the actual temperature deviates from the threshold by more than 1°C, the threshold is reset to ensure the reliability of the protection action. Based on the preset anti-icing monitoring period, the return air temperature of all running compressors is scanned cyclically. The preset anti-icing monitoring period is the default temperature scanning interval of the system, which is set to 30 seconds. This interval can ensure that the temperature drop is found in time to avoid missing the warning opportunity, and it will not occupy system resources due to too frequent scanning. The running compressor refers to the compressor currently in the starting state. The system will read the feedback signal of the compressor contactor in real time to exclude the stopped or faulty compressors and reduce scanning redundancy. The cyclic scanning adopts the numbering order: Starting from the first compressor, the data of its return air temperature sensor is read, compared with the warning and protection thresholds of the compressor, and the status is recorded. After scanning the last compressor, the next round starts with an interval of 30 seconds. To avoid scanning delay, the system uses multi-thread parallel technology: The 10 compressors are divided into 2 groups, 5 in each group, and scanning is performed simultaneously, the total scanning time is controlled within 5 seconds, and there is enough time to process the scanning results within 30 seconds, if it is found that a certain compressor is in the pre-warning or protection state for 2 rounds after scanning, the corresponding compressor number and state are displayed on the system interface, and an audible and visual prompt is issued, so that the operation and maintenance personnel can pay attention in time, when it is detected that the return air temperature of a certain compressor is lower than its pre-warning threshold but higher than the protection threshold, the compressor rotation operation is started, which is lower than the pre-warning threshold but higher than the protection threshold, that is, the temperature is in the pre-warning interval, indicating that the compressor has icing risk, but it has not reached the emergency protection level, at this time, if it is directly closed, it will lead to a decrease in system cooling capacity, if it continues to run, the risk will increase, therefore, it is necessary to replace the compressor without stopping through rotation, balance the risk and cooling capacity stability, the core of rotation operation is to start and stop first, start a standby compressor first, and then close the pre-warning compressor after it runs stably, to avoid cooling capacity interruption, rotation triggering needs to meet two conditions, one is that the temperature of the compressor is in the pre-warning interval for 2 rounds of scanning, and the other is that there is at least one standby compressor in the current system, if all compressors are running, the load of a certain compressor needs to be reduced to make it enter standby state before rotation, to prevent insufficient cooling capacity caused by no standby compressor, that is, according to the layout relationship of the cooler pipe, start a standby compressor farthest from the physical position of the compressor, the layout relationship of the cooler pipe refers to the physical distribution of the refrigerant pipe corresponding to each compressor in the cooler, usually the cooler adopts parallel multi-loop design, each compressor corresponds to an independent refrigerant loop, the loops are arranged at a certain interval to avoid the superposition of adjacent loop cooling capacity leading to local temperature being too low, the farthest distance needs to rely on the pre-stored pipe position coordinates, during system installation and debugging, the center coordinates of each compressor loop are measured by laser range finder (such as 1 loop coordinates (1.0, 1.0), 3 (3.0, 3.0), 5 (5.0, 1.0)), the straight line distance between the pre-warning compressor and all standby compressors is calculated, and the one with the longest distance is selected, for example, 1 compressor is pre-warning, standby compressors are 3 and 5, the distance between 1 and 3 is 2.83m, and the distance between 1 and 5 is 4.0m, the farthest standby compressor loop is selected, and the reason for selecting the farthest standby compressor loop is that the farthest standby compressor loop has no cold superposition area with the pre-warning compressor loop, and after starting, the cold can be quickly supplemented, and at the same time, the cold concentration of the adjacent loop is avoided to cause the local temperature to further decrease. Before starting, the standby compressor state needs to be checked first: the return air temperature sensor, motor current and oil pressure data of the standby compressor are read to ensure that there is no fault. If the standby compressor has a fault, the second farthest standby compressor is selected. If all standby compressors are faulty, an alarm signal of no standby compressor is sent, and the load of the pre-warning compressor is reduced instead of being directly turned off, so as to maximize the maintenance of the cold output. After the new compressor runs stably, the compressor in the pre-warning state is turned off. The determination of stable running needs to be made by comprehensively considering multiple parameters. After the new compressor is started, the return air temperature, motor current and outlet temperature of the surface cooler of the system are continuously monitored. If the return air temperature is stable at 8°C~12°C (the temperature interval of normal operation of the compressor), the current fluctuation is ≤5% (no overload), the outlet temperature of the surface cooler is stably decreased (the cold output is normal), and the system continuously runs for 2 minutes, it is determined that the system is stable. The closing opportunity needs to be gradual. After the new compressor is stable, the refrigerant flow of the pre-warning compressor is reduced by 50% first, and the system total cold is observed for 1 minute. Whether the cold is stable or not is determined by the change of the outlet temperature of the surface cooler. If the cold does not decrease obviously, the refrigerant solenoid valve of the pre-warning compressor is completely closed, and the motor power is cut off after 10 seconds to avoid the sudden stop of the system to cause the sudden decrease of the system cold. After being turned off, the return air temperature of the pre-warning compressor needs to be continuously monitored. If the temperature rises above the pre-warning threshold (for example, from 3°C to 6°C) and lasts for 5 minutes, the pre-warning compressor is included in the standby compressor list and started when needed next time. If the temperature is still below the pre-warning threshold, it is determined that the pipeline may be frozen, and a prompt signal of needing to check the return air pipeline is sent to inform the operation and maintenance personnel to troubleshoot. Through such accurate selection and stable rotation of the compressor, the icing risk can be eliminated in time, the system cold output can be stabilized, the indoor temperature and humidity can be prevented from fluctuating, and the specific implementation of the emergency operation after the threshold is triggered is as follows. When the compressor suction temperature is detected to be lower than the protection threshold, the compressor is immediately turned off. When the suction temperature is lower than the protection threshold (e.g., the protection threshold is 2°C, and the current temperature is 1°C), the system needs to shut down the risk as quickly as possible. First, send a power-off signal to the main contactor of the compressor to cut off the power supply of the motor and stop the compressor from running. At the same time, send a closing signal to the refrigerant solenoid valve corresponding to the compressor to cut off the passage of refrigerant flowing to the suction pipe, preventing more liquid refrigerant from entering the suction pipe and exacerbating icing. The immediate response time needs to be controlled within 100ms. The system uses hardware interrupt priority design, and sets the suction temperature lower than the protection threshold as the highest priority interrupt. Once this condition is detected, other non-urgent tasks (such as data statistics) are suspended, and the shutdown operation is performed first to avoid delays that may cause the fault to expand. After shutdown, key information needs to be recorded: the shutdown time, the suction temperature before shutdown, the continuous running time of the compressor, and the current load data are stored in the fault log for subsequent maintenance personnel to analyze the fault cause. If multiple compressors are below the protection threshold at the same time (e.g., two compressors trigger at the same time), the compressor with the lowest temperature is closed first in order of temperature from low to high, and the others are processed in turn. The lower the temperature, the higher the risk, and it needs to be handled first. At the same time, avoid shutting down multiple compressors at once to cause a cold load interruption, and simultaneously start two preset associated compressors. The preset associated compressor is a compressor that the system pre-stores and has a complementary relationship with the faulty compressor in terms of piping layout. Its selection needs to be based on the piping layout of the surface cooler. Each compressor is associated with two compressors, for example, 1 compressor is associated with 3 and 5, and 2 is associated with 4 and 6. The association relationship is determined by the piping distance and cold load matching degree during system installation. The total refrigeration capacity of the associated compressor needs to be slightly higher than that of the faulty compressor (e.g., the faulty compressor has a refrigeration capacity of 5kW, and the associated compressor has a refrigeration capacity of 3kW each, with a total refrigeration capacity of 6kW), to ensure that the cold load can be quickly supplemented and the system cold load does not drop too much. At the same time of shutting down the faulty compressor, send a start signal to the contactors of the two associated compressors, with a start interval of ≤1 second to minimize the cold load interruption time. Before starting, a quick self-check needs to be performed: within 100ms, detect the suction temperature of the associated compressor (which needs to be ≥5°C), the motor insulation resistance (which needs to be ≥0.5MΩ), and the oil pressure (which needs to be ≥0.2MPa), ensure no failure, if the self-checking of a certain associated compressor fails (such as the return gas temperature 3℃), the standby associated compressor (such as 1 associated 3 failure, start standby 7) is immediately started, if both associated compressors are faulty, an emergency machine shortage sound and light alarm is sent out, at the same time the load of other running compressors is reduced (such as reducing the refrigerant flow), avoiding the triggering of protection of other compressors due to sudden increase of load, maintaining the basic cold output, the newly started two compressors continue to run for a minimum protection running time, which is the shortest time to ensure the stable operation of the associated compressor and the steady-state cold output, usually set to 5 minutes, after the new compressor is started, it needs to go through three stages of startup initial stage (low cold) → acceleration period (cold rising) → steady state (cold stable), 5 minutes can ensure it enters the steady state, avoiding the system cold fluctuation caused by starting and stopping repeatedly, the time monitoring starts from the successful start of both associated compressors, if one of them fails, only monitor the one that starts successfully, the time does not change, if both start successfully, they are counted simultaneously, the monitoring in operation cannot be ignored: the system collects the return gas temperature, current and table cooler outlet temperature of the two associated compressors every 30 seconds, if the return gas temperature of a certain compressor is lower than the early warning threshold (such as 5℃), its load is immediately reduced (such as closing the small expansion valve), avoiding it also entering the protection state, if the table cooler outlet temperature drops too fast (such as 3℃ in 5 minutes), the refrigerant flow of the two compressors is appropriately reduced to balance the cold supplement and temperature stability, if the indoor temperature and humidity deviation is large at this time, the minimum protection running time is automatically extended to 10 minutes to ensure enough time to supplement the cold, avoiding the deterioration of indoor environment, according to the real-time return gas temperature data, the one with the lowest temperature is closed to realize system energy balance, the real-time return gas temperature data refers to the return gas temperature of the two associated compressors collected every 30 seconds, the temperature difference reflects the load difference of the two compressors, the lower the temperature, the lower the superheat of the refrigerant sucked by the compressor, the higher the load, the higher the temperature, the lower the load, the one with the lowest temperature is closed, which is the compressor with higher load, by reducing the operation of high-load compressor, the load state of the two compressors is balanced, avoiding the energy waste or failure risk caused by one overload and one light load, the closing process needs to be smooth transition: first reduce the refrigerant flow of the compressor to be closed by 50%, maintain for 1 minute, monitor the total cold output of the system (judged by the table cooler outlet temperature); if the cold output does not decrease significantly (such as temperature fluctuation ≤0.5℃), and then completely close the refrigerant solenoid valve thereof, and turn off the motor power supply after 10 seconds. After turning off, the energy balance effect needs to be verified: monitor the return air temperature of the remaining compressor (such as 3) and the indoor temperature and humidity, if the return air temperature is stable at 8℃~12℃ (normal interval), the indoor temperature and humidity deviation is ≤1℃ and 2%RH, then it is determined that the balancing is successful; if the temperature of the remaining compressor is still lower than the early warning threshold, or the indoor temperature and humidity fluctuates too much, then adjust again (such as reducing the load of the remaining compressor, starting other standby compressors), until the system reaches a stable state, through this process of emergency shutdown-quick cold supplement-balance load, both the risk of failure can be quickly eliminated, and the system stability can be maximized to maintain, to ensure that the indoor environment is not greatly affected, and the specific implementation of the ice prevention monitoring cycle length adjustment mechanism is that when the adjustable limit level is floated, the maximum input proportion of the compressor increases (such as from 90% to 100%), the number of running compressors increases, and the probability of the return air temperature being lower than the early warning threshold also rises. If the original ice prevention monitoring cycle (such as 30 seconds) is still used, it may not be able to timely discover the temperature drop risk of multiple compressors at the same time, resulting in icing or liquid knock failure; therefore, the monitoring cycle length needs to be dynamically adjusted, the scanning frequency is optimized according to the number of running compressors and the temperature state, to ensure quick response to temperature changes, and the specific implementation is as follows: the ice prevention monitoring cycle length adjustment mechanism specifically includes: When the adjustable limit level position is floated, the adjustable limit level position is floated, which is the trigger condition of the adjustment mechanism. The reheat demand judgment unit 2 sends the position floating signal (such as floating to level 5) to the anti-icing protection control unit 3 through the system internal CAN bus in real time, and the transmission delay is ≤100 ms, which ensures that the anti-icing unit can respond immediately. After triggering, the anti-icing unit first reads the current number of running compressors (such as 10 all running) and the return air temperature state (normal, warning) of each compressor, which is prepared for subsequent judgment. If the position is continuously floated in a short time (such as from level 3→4→5), the adjustment process is restarted after each float to use the latest position and running state, avoiding adjustment lag caused by multiple floats. At the same time, the system records the position floating time, the monitoring period before adjustment (such as 30 seconds) and the current number of running compressors, and stores them into the adjustment log, which facilitates the recovery of the original period when the position is lowered (such as the position is lowered from 5 to 4, and the 30-second period is recovered). If more than half of the compressors in the current running compressors have return air temperature below the warning threshold, the current number of running compressors refers to the number of compressors actually started after the position is floated (such as 10 in total, all started for 10; if 2 are faulty, the running number is 8). Faulty or standby compressors need to be excluded to ensure the accuracy of the statistical base. The more than half criterion is that the number of compressors below the warning threshold is greater than 50% of the running number (for example, 10 running, 6 below the warning threshold (6>5), triggering adjustment; 8 running, 5 below the warning threshold (5>4), also triggering adjustment). If the running number is odd (such as 7), more than half means 4 or more; if the running number is ≤2 (such as 2), more than half means 2 below the warning threshold, which all need to trigger adjustment. The judgment of return air temperature below the warning threshold needs to be based on the independent warning threshold of each compressor (such as 1 warning threshold 5℃, 26℃), not a unified threshold, to ensure accurate judgment. For example, 2 compressors have temperature 5.5℃, which is below the warning threshold of 6℃, and is judged as below the warning threshold, while 1 compressor has temperature 5.5℃, higher than its early warning threshold 5℃, determine normal, determine the cycle set for gear up after every 2 minutes, the system every 2 minutes statistics once below the early warning threshold compressor quantity, continuous 2 times statistics all more than half, only then execute cycle adjustment, avoid single statistics error (such as the temperature of a compressor temporary decline) lead to the adjustment of the problem, then the original anti-icing monitoring cycle length is shortened to the original length divided by the number of running compressors, the original anti-icing monitoring cycle length refers to the default period before the gear up, usually 30 seconds, the period is based on the scene of fewer running compressors set (such as 6 run, 30 seconds period enough), the quotient calculation, that is, the new monitoring period = original period ÷ current running compressor number, when calculating, use integer division, keep integer seconds, for example, the original period 30 seconds, the current running number 10, new period = 30 ÷ 10 = 3 seconds, running number 6, new period = 30 ÷ 6 = 5 seconds, running number 5, new period = 6 seconds, to avoid too many running numbers leading to new period too short (such as 20 run, 30 ÷ 20 = 1.5 seconds, too frequent), the system sets the minimum lower limit of the new period to 2 seconds: even if the quotient < 2 seconds (such as 30 seconds ÷ 20 sets = 1.5 seconds), also execute 2 seconds, to prevent scanning too frequent occupation system CPU resources, cause other control tasks delay, after calculation, the system automatically updates the scanning interval of the anti-icing monitoring module, without manual intervention, for example, the original 30 seconds period, after updating, scan every 3 seconds all running compressors back gas temperature, the scanning efficiency is greatly improved, by shortening the scanning interval to speed up the compressor rotation frequency, the core purpose of shortening the scanning interval is that the new period is greatly shortened than the original period, which can make the anti-icing unit find the compressor with decreased back gas temperature faster.

[0009] In the present application, the data acquisition unit 1 collects outdoor temperature and humidity coupling data and compressor back gas temperature data through outdoor temperature and humidity sensors and back gas temperature sensors, the reheating demand judgment unit 2 implements temperature feedforward control based on outdoor temperature and humidity, sets adjustable limit level to restrict compressor input proportion, calculates indoor, target and outdoor air moisture content when all compressors are input and humidity exceeds the standard, adjusts the integral speed of the cooling and dehumidification PID controller and the adjustable limit level, combines transient temperature judgment to determine reheating demand when the gear is up, and the anti-icing protection control unit 3 periodically monitors the back gas temperature and implements measures, solving the problems of uncoordinated temperature and humidity control and inaccurate anti-icing protection in traditional systems.

[0010] The basic principles, main features and advantages of the present application are shown and described above, and those skilled in the art should understand that the present application is not limited to the above examples, the above examples and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application, various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application, the scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A group control energy modulation system for a fixed frequency compressor based on outdoor temperature and humidity coupling, characterized in that, Comprise: The data acquisition unit (1) collects outdoor temperature and humidity data and the return air temperature data of each compressor through outdoor temperature and humidity sensors and return air temperature sensors; The reheating demand judgment unit (2) performs first step temperature feedforward control based on outdoor temperature and humidity data, sets adjustable limit level to preliminarily constrain compressor input proportion, continuously monitors running time when all compressors are put into operation, evaluates whether the sampled temperature and humidity is within the set deviation range when the running time reaches the set value, calculates the air moisture content state of indoor sampling point, set point and outdoor working condition point when the humidity sampling value is higher than the upper limit of the set deviation, and judges whether to adjust the integral action speed of the cooling and dehumidifying PID controller and the adjustable limit level by comparing the air moisture content state, wherein the adjustable limit level is raised when the adjustable limit level is raised. The anti-icing protection control unit (3) compares the return air temperature of each compressor with the preset warning value and protection value by periodic monitoring, starts the compressor rotation operation when the return air temperature is lower than the warning value, stops the compressor immediately and starts two other compressors to supplement energy when the return air temperature drops to the protection value, and then optimizes the shutdown to realize energy balance, and adjusts the anti-icing monitoring cycle length according to the number of opened compressors when the adjustable limit level is raised, reduces the scanning frequency to speed up the rotation and reduce the icing risk.

2. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 1, characterized in that: The data acquisition unit (1) realizes outdoor temperature and humidity coupling data acquisition through outdoor temperature and humidity sensors, and collects the return air temperature data of each compressor through the return air temperature sensors independently installed on the return air pipe of each fixed-frequency compressor. The return air temperature sensor is located at the pipe section position where the refrigerant flows out of the surface cooler in the corresponding compressor circuit.

3. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 2, characterized in that: The first step temperature feedforward control performed by the reheating demand judgment unit (2) adopts adjustable limit level strategy, which specifically includes: The adjustable limit level strategy divides several temperature intervals according to outdoor temperature and sets the maximum input proportion upper limit value of the compressor corresponding to each temperature interval. When all the compressors used for calculation are put into operation and the continuous running time reaches the set time length, and the humidity sampling value is continuously higher than the set deviation upper limit, the moisture content state calculation mechanism is triggered.

4. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 3, characterized in that: The implementation of the moisture content state calculation mechanism specifically includes: The current air moisture content state value is calculated based on the indoor temperature and humidity sampling value, the target moisture content state value is calculated based on the set temperature and humidity value, and the outdoor moisture content state value is calculated based on the outdoor temperature and humidity value. The comparison relationship among the three groups of moisture content states determines the adjustment direction of the PID control parameters: When the indoor moisture content state value does not exceed the target value, the original cooling and dehumidifying demand is maintained, but the reheating PID integral action is accelerated. When the indoor moisture content state value exceeds the target value and the outdoor moisture content state value is better than the target value, the cooling and dehumidifying PID integral action is enhanced and the reheating demand is evaluated. When the outdoor moisture content state value is worse than the target value, the adjustable limit level is raised and the cooling and dehumidifying PID integral action is suppressed.

5. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 4, characterized in that: The implementation of the adjustable limit level raising operation specifically includes: When it is determined that the outdoor moisture content state value is worse than the target value, the current adjustable limit level is raised to the adjacent high level, which is used to break through the original proportion upper limit constraint of the first step temperature feedforward control.

6. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 5, characterized in that: The anti-icing protection control unit (3) sets independent return air temperature warning threshold and protection threshold for each compressor, and performs cyclic scanning on the return air temperature of all running compressors based on the preset anti-icing monitoring period; When the return air temperature of a certain compressor is detected to be lower than the warning threshold but higher than the protection threshold, the compressor rotation operation is started, that is, according to the layout relationship of the air cooler pipeline, the standby compressor farthest from the physical position of the compressor is started, and after the new compressor is stable, the original compressor in the warning state is closed.

7. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 6, characterized in that: When the return air temperature of a certain compressor is detected to be lower than the protection threshold, the compressor is immediately closed and two preset associated compressors are simultaneously started, and after the two newly started compressors are continuously operated for a minimum protection operation time, the one with the lowest temperature is closed according to the real-time return air temperature data to realize system energy balance.

8. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 7, characterized in that: The length adjustment mechanism of the anti-icing monitoring period specifically includes: when the adjustable limit level is floated, if more than half of the running compressors have return air temperature lower than the warning threshold, the original anti-icing monitoring period is shortened to the quotient of the original length divided by the number of running compressors, and the scanning interval is shortened to accelerate the compressor rotation frequency.

9. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 8, characterized in that: The compressor rotation operation relies on the distance parameter preset by the layout of the air cooler pipeline, and in the rotation process, the residual cooling complementary effect is formed by the cooling transfer time difference between the newly started compressor and the stopped compressor, which reduces the icing risk and maintains the stability of the total cooling output of the system.

10. The group control energy modulation system based on outdoor temperature and humidity coupling according to claim 9, characterized in that: The reheating demand judgment unit (2) and the anti-icing protection control unit (3) form a two-way coupling, specifically including: The adjustable limit level change triggers the anti-icing monitoring period adjustment, and the compressor rotation state is fed back to the reheating PID calculation module in real time, and the temperature and humidity control and the anti-freezing protection are optimized through two-way data interaction.

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