Method and device for controlling operation of water chiller, electronic equipment and medium

Abstract

The application discloses a kind of chiller operation control method, device, electronic equipment and storage medium, wherein the method comprises: according to current cooling medium temperature information, current chilled water inlet temperature, current chilled water inlet and outlet temperature difference value, current compressor power information, current cooling medium conveying device power information and chilled water inlet and outlet temperature difference target value, confirm compressor target speed and cooling medium conveying device target speed;According to the compressor target speed control compressor, according to the cooling medium conveying device target speed control cooling medium conveying device, can control the chilled water actual outlet temperature of chiller at the same time, according to current working condition control compressor power and cooling medium conveying device power, namely adjust unit power, so as to ensure effective cooling at the same time, reach the effect of reducing unit consumption power, realize energy saving.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a method, apparatus, electronic device and medium for operating control of a chiller unit. Background Technology

[0002] Chillers are commonly used for temperature control in liquid-cooled energy storage batteries, residential areas, etc. In order to achieve the ideal cooling effect, it is necessary to properly control the compressor, fan, water pump, etc. of the chiller during actual operation so that the actual outlet temperature of the chilled water matches the target outlet temperature.

[0003] In related technologies, the chilled water outlet temperature of chiller units is usually regulated by controlling the compressor speed: for example, detecting the actual chilled water outlet temperature of the chiller unit and calculating the difference between it and the target outlet temperature; based on this difference, the target compressor speed is obtained by using a PID control algorithm.

[0004] In the process of realizing this invention, the inventors discovered that the related technology has at least the following problems: when the chiller unit is actually working, the power consumption of the unit is greatly affected by different operating conditions. According to the aforementioned method, when the unit is actually running, the reasonable control of the overall power consumption of the unit is not considered under different operating conditions, which results in a certain amount of energy waste in most operating conditions. Summary of the Invention

[0005] This application provides a method, device, electronic equipment, and storage medium for operating a chiller unit. The method adjusts the compressor speed and cooling medium delivery device speed of the chiller unit based on compressor power information, cooling medium delivery device power information, and other temperature information. This reduces the unit's power consumption while ensuring effective cooling, thus achieving energy-saving effects.

[0006] Firstly, a method for operating and controlling a chiller unit is provided, including:

[0007] Based on the current cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference, the target speed of the compressor and the target speed of the cooling medium delivery device are determined.

[0008] The compressor is controlled according to the target speed of the compressor, and the cooling medium delivery device is controlled according to the target speed of the cooling medium delivery device.

[0009] Secondly, an operation control device for a chiller unit is provided, comprising:

[0010] The predictive control module is used to determine the target speed of the compressor and the target speed of the cooling medium delivery device based on the current cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference.

[0011] The control module is used to control the compressor according to the target speed of the compressor and to control the cooling medium delivery device according to the target speed of the cooling medium delivery device.

[0012] Thirdly, an electronic device is provided, including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform steps as described in the first aspect and any possible implementation thereof.

[0013] Fourthly, a computer storage medium is provided, the computer storage medium storing one or more instructions, the one or more instructions being adapted to be loaded by a processor and executed as described in the first aspect above and any possible implementation thereof.

[0014] The operation control method for the chiller unit in this application includes at least the following effects:

[0015] Based on the current cooling medium temperature, current chilled water inlet temperature, current chilled water inlet / outlet temperature difference, current compressor power, current cooling medium delivery device power, and target chilled water inlet / outlet temperature difference, the target compressor speed and target cooling medium delivery device speed are determined. The compressor operation is controlled according to the target compressor speed, and the cooling medium delivery device operation is controlled according to the target cooling medium delivery device speed. Compared to the general method of controlling compressor speed based on the difference between the actual outlet water temperature and the target outlet water temperature, this method can control the actual outlet water temperature of the chiller unit while also considering the current operating conditions of the chiller unit, including the current cooling medium temperature, current chilled water inlet temperature, current chilled water inlet / outlet temperature difference, current compressor power, and current cooling medium delivery device power. This allows for more rational control of compressor power and cooling medium delivery device power to reduce power consumption, thereby achieving energy savings while ensuring effective cooling. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0017] Figure 1 A flowchart illustrating an operation control method for a chiller unit provided in this application embodiment;

[0018] Figure 2 A schematic diagram of the input and output parameters of a model predictive controller for a chiller unit provided in this application embodiment;

[0019] Figure 3 A schematic diagram of the input and output variables of a chiller unit prediction model provided in this application embodiment;

[0020] Figure 4 A schematic diagram of the system structure of an air-cooled chiller unit provided in this application embodiment;

[0021] Figure 5 A schematic diagram of input and output parameters of a model predictive controller for an air-cooled chiller unit provided in this application embodiment;

[0022] Figure 6 A schematic diagram of the input and output variables of a predictive model for an air-cooled chiller unit provided in this application embodiment;

[0023] Figure 7 A schematic diagram of the system structure of a water-cooled chiller unit provided in this application embodiment;

[0024] Figure 8 A schematic diagram of input and output parameters of a model predictive controller for a water-cooled chiller unit provided in this application embodiment;

[0025] Figure 9 A schematic diagram of the input and output variables of a prediction model for a water-cooled chiller unit provided in an embodiment of this application;

[0026] Figure 10 A schematic diagram of the operation control device for a chiller unit provided in this application embodiment;

[0027] Figure 11 This is a schematic diagram of the structure of an electronic device provided in this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0029] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0030] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] The loss function or cost function mentioned in the embodiments of this application is a function that maps the values ​​of a random event or its related random variables to non-negative real numbers to represent the "risk" or "loss" of the random event.

[0032] The embodiments of this application are described below with reference to the accompanying drawings.

[0033] Please see Figure 1 , Figure 1 A flowchart illustrating an operation control method for a chiller unit provided in this application embodiment is shown below. Figure 1 As shown, the method includes:

[0034] 101. Based on the current cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference, confirm the target speed of the compressor and the target speed of the cooling medium delivery device;

[0035] 102. Control the operation of the compressor according to the target speed of the compressor, and control the operation of the cooling medium conveying device according to the target speed of the cooling medium conveying device.

[0036] The chiller unit operation control method in this application embodiment can be applied to a chiller unit system. This chiller unit system may include a compressor, a cooling medium delivery device, an expansion valve, and an evaporator. The cooling medium temperature information refers to the current temperature information of the cooling medium related to the cooling medium delivery device. In the chiller unit system, the cooling medium differs depending on the cooling medium delivery device used. For example, the cooling medium delivery device may be a condenser fan or a cooling water pump. If the cooling medium for a condenser fan is air, then the cooling medium temperature information can be the current ambient air temperature; if the cooling medium for a cooling water pump is water, then the cooling medium temperature information can be the current cooling water inlet temperature.

[0037] In this application embodiment, the “current” value can be understood as the real-time parameter value (actual value) collected during system operation; the “target” value can be understood as the pre-set ideal parameter value.

[0038] The current temperature difference between the chilled water inlet and outlet can be calculated based on the collected current chilled water inlet temperature and current chilled water outlet temperature. Specifically, temperature sensors can be installed on the chilled water inlet and outlet pipes of the chiller unit to detect the chilled water inlet temperature Twater_r and the chilled water outlet temperature Twater_o, respectively. The measured values ​​can be recorded as the current chilled water inlet temperature Twater_r_actl and the current chilled water outlet temperature Twater_o_actl.

[0039] The temperature difference between the inlet and outlet of chilled water is represented by ΔTwater. The current temperature difference between the inlet and outlet of chilled water is ΔTwater_actl = Twater_r_actl - Twater_o_actl; the target temperature difference between the inlet and outlet of chilled water is ΔTwater_tgt = Twater_r_actl - Twater_o_tgt, where Twater_o_tgt is the preset target temperature of the outlet of chilled water, which can generally be taken as an empirical value or an industry recommended value.

[0040] Optionally, the aforementioned current compressor power information includes the Nth root of the current compressor power, and the aforementioned current cooling medium delivery device power information includes the Nth root of the current cooling medium delivery device power.

[0041] Optionally, the current compressor power and the current cooling medium delivery device power can be obtained by using sensors; or,

[0042] The power of the compressor is calculated based on its voltage and current, and the power of the cooling medium delivery device is calculated based on its voltage and current.

[0043] Specifically, the compressor power P_comp can be directly detected by sensors or indirectly calculated based on voltage and current. The actual detected value or the indirectly calculated value is recorded as the current compressor power P_comp_actl, and the Nth root of the current compressor power is recorded as nRoot_P_comp_actl.

[0044] Similarly, the power of the cooling medium conveying device can be directly detected by sensors or indirectly calculated based on voltage, current or speed. The actual detected value or the indirectly calculated value is recorded as the current power of the cooling medium conveying device. Further calculation can obtain the Nth root of the current power of the cooling medium conveying device.

[0045] In this embodiment, model predictive control algorithm is mainly used to control the compressor speed and the cooling medium delivery device speed, so as to simultaneously adjust the chilled water outlet temperature and unit power, thereby reducing the unit's power consumption and achieving energy saving while ensuring effective cooling.

[0046] In one optional implementation, step 101 includes:

[0047] 011. Calculate the loss value based on the above-mentioned current cooling medium temperature information, the above-mentioned current chilled water inlet temperature value, the above-mentioned current chilled water inlet and outlet temperature difference value, the above-mentioned current compressor power information, the above-mentioned current cooling medium delivery device power information, and the above-mentioned chilled water inlet and outlet temperature difference target value;

[0048] 012. Obtain the compressor speed and the cooling medium conveying device speed when the above-mentioned loss value is minimized, and use them as the target speed of the compressor and the target speed of the cooling medium conveying device, respectively.

[0049] Specifically, when the chiller unit is running, the chilled water pump maintains a constant speed; at the same time, a model predictive controller can be used to control the compressor speed and the speed of the cooling medium delivery device.

[0050] The main method is as follows: the predictive controller can use a mature optimization solver to solve for the compressor speed and cooling medium delivery device speed that minimize the loss value. These are used as the target speeds for the compressor and cooling medium delivery device, respectively. This allows for the control of the unit power while adjusting the temperature difference between the inlet and outlet of the chilled water: making the actual value of the chilled water outlet temperature equal to the target value, while minimizing the unit power.

[0051] In an optional implementation, step 011 above includes:

[0052] 0111. Input the above-mentioned current cooling medium temperature information, the above-mentioned current chilled water inlet temperature value, compressor speed and cooling medium delivery device speed into the chiller unit model, and calculate based on the above-mentioned current chilled water inlet and outlet temperature difference value, the above-mentioned current compressor power information and the above-mentioned current cooling medium delivery device power information, and output the predicted value of chilled water inlet and outlet temperature difference, the predicted compressor power information and the predicted power information of cooling medium delivery device.

[0053] 0112. Input the predicted temperature difference between the inlet and outlet of the chilled water, the predicted power of the compressor, and the predicted power of the cooling medium conveying device into a preset cost function to calculate the loss value under different compressor speeds and cooling medium conveying device speeds.

[0054] The aforementioned preset cost function is a loss function. In this embodiment, a cost function related to the temperature difference between the inlet and outlet of chilled water, the power of the compressor, and the power of the cooling medium delivery device can be designed to calculate the loss value under different conditions. This allows the compressor speed and the cooling medium delivery device speed with the minimum loss value to be selected, and the operation of the compressor and the cooling medium delivery device to be controlled. In this case, the current temperature difference between the inlet and outlet of chilled water can be controlled to reach the target value while the power of the compressor and the cooling medium delivery device is minimized, thus achieving the unit's energy-saving effect.

[0055] For details, please refer to Figure 2 The diagram shows the input and output parameters of a predictive controller for a chiller unit model. Figure 3 This is a schematic diagram of the input and output variables of a chiller prediction model provided in an embodiment of this application.

[0056] The input and output parameters of the model predictive controller are set as follows: Figure 2 As shown, the current cooling medium temperature, current chilled water inlet temperature, target chilled water inlet and outlet temperature difference, current chilled water inlet and outlet temperature difference, current compressor power, and current cooling medium delivery device power are the inputs of the model predictive controller, and N can generally be taken as 2; the compressor target speed and the cooling medium delivery device target speed are the outputs of the model predictive controller.

[0057] The chiller unit model is the prediction model called by the model predictive controller. The prediction model called by the model predictive controller can be a conventional linear time-invariant model, such as a state-space model or a step response model. Its input and output variables can be set as follows: Figure 3As shown. The cooling medium temperature, chilled water inlet temperature, compressor speed, and cooling medium delivery device speed are the input variables of the model. The cooling medium temperature and chilled water inlet temperature are measurable disturbance variables (i.e., obtainable through real-time monitoring), while the compressor speed and cooling medium delivery device speed are controllable variables. Controllable variables here refer to variables whose specific values ​​can be selected for calculation, such as randomly selecting corresponding compressor speeds and cooling medium delivery device speeds. The current chilled water inlet and outlet temperature difference, the Nth root of the compressor power, and the Nth root of the cooling medium delivery device power are measurable output variables of the model. The parameters of the prediction model can be constructed using mature system identification methods and tools.

[0058] Specifically, the prediction model can calculate the predicted value of the chilled water inlet and outlet temperature difference, the predicted compressor power, and the predicted cooling medium delivery device based on the current cooling medium temperature information, the current chilled water inlet and outlet temperature value, the current compressor power information, and the current cooling medium delivery device power information. Its output results are used to calculate the cost function, with the goal of minimizing the cost function.

[0059] The aforementioned preset cost function is the cost function of the aforementioned model predictive controller, used to calculate the loss value under different compressor speed values ​​and cooling medium delivery device speed values.

[0060] In one alternative implementation, the cost function cost_func of the model prediction controller is defined as follows:

[0061]

[0062] Wherein, ΔTwater(i), ΔTwater_tgt(i), nRoot_P_comp(i), and nRoot_P_oP(i) represent the predicted value ΔTwater of the chilled water inlet and outlet temperature difference at the i-th prediction time, the target value ΔTwater_tgt of the chilled water inlet and outlet temperature difference, the compressor power prediction information (the Nth root predicted value of the compressor power nRoot_P_comp), and the cooling medium delivery device prediction information (the Nth root predicted value of the cooling medium delivery device power nRoot_P_oP), respectively; p is the prediction time domain, wt is the temperature difference weighting coefficient, and wp is the power weighting coefficient, which can be determined as needed when setting the model prediction controller parameters. The above cost function can also be designed as needed, and this application embodiment does not impose any restrictions on this.

[0063] In an optional embodiment, if the cooling medium conveying device is a condenser fan, the cooling medium temperature information can be the current ambient air temperature value.

[0064] If the aforementioned cooling medium delivery device is a cooling water pump, the aforementioned cooling medium temperature information can be the current cooling water inlet temperature value.

[0065] Furthermore, if the aforementioned cooling medium conveying device is a condenser fan, and the cooling medium temperature information is the current ambient air temperature, the chiller unit operation control method provided in this application embodiment is applicable to an air-cooled chiller unit system. If the aforementioned cooling medium conveying device is a cooling water pump, and the cooling medium temperature information is the current cooling water inlet temperature, the chiller unit operation control method provided in this application embodiment is applicable to a water-cooled chiller unit system.

[0066] The control methods for these two types of chiller systems are described below:

[0067] I. See also Figure 4 The diagram shows a system structure of an air-cooled chiller unit.

[0068] like Figure 4 As shown, the air-cooled chiller unit includes a compressor, an air-cooled condenser (including a condenser fan), an expansion valve, and an evaporator. The evaporator is connected to the chilled water inlet pipe and the chilled water outlet pipe, and the chilled water outlet pipe is connected to the chilled water pump. Temperature sensors can be installed on the chilled water inlet pipe and the chilled water outlet pipe of the air-cooled chiller unit to detect the chilled water inlet temperature Twater_r and the chilled water outlet temperature Twater_o, respectively. The measured values ​​are recorded as the current chilled water inlet temperature value Twater_r_actl and the current chilled water outlet temperature value Twater_o_actl, respectively. The temperature difference between the chilled water inlet and outlet is represented by ΔTwater, then the current inlet and outlet temperature difference ΔTwater_actl = Twater_r_actl - Twater_o_actl; the target temperature difference ΔTwater_tgt = Twater_r_actl - Twater_o_tgt, where Twater_o_tgt is the target value of the chilled water outlet temperature, which can generally be taken as an empirical value or an industry-recommended value.

[0069] Based on the description of the foregoing embodiments, the operation control method for an air-cooled chiller unit may include:

[0070] 201. Based on the current ambient air temperature, current chilled water inlet temperature, current chilled water inlet and outlet temperature difference, current compressor power information, current condenser fan power information, and target chilled water inlet and outlet temperature difference, confirm the target compressor speed and the target condenser fan speed.

[0071] 202. Control the operation of the compressor according to the target speed of the compressor, and control the operation of the condenser fan according to the target speed of the condenser fan.

[0072] Figure 5This is a schematic diagram of the input and output parameters of a model predictive controller for an air-cooled chiller unit, provided in an embodiment of this application.

[0073] Figure 6 This is a schematic diagram of the input and output variables of a predictive model for an air-cooled chiller unit provided in an embodiment of this application.

[0074] The operation and control methods for air-cooled chillers can be referenced. Figure 1 The specific descriptions of the embodiments shown are not repeated here.

[0075] Specifically, during the operation of the air-cooled chiller unit, the chilled water pump maintains a constant speed. At the same time, a model predictive controller is used to control the compressor speed and condenser fan speed. The main method is that the predictive controller can use a mature optimization solver to find the compressor speed and condenser fan speed values ​​that minimize the loss value. These are used as the target speeds for the compressor and condenser fan, respectively. This allows for the control of the unit power while adjusting the temperature difference between the inlet and outlet chilled water, so that the actual value of the chilled water outlet temperature equals the target value, and the unit power is minimized.

[0076] The input and output parameters of the model predictive controller are as follows: Figure 5 As shown, the current ambient air temperature value OAT_actl, the current chilled water inlet temperature value Twater_r_actl, the target chilled water inlet and outlet temperature difference value ΔTwater_tgt, the current chilled water inlet and outlet temperature difference value ΔTwater_actl, the Nth root of the current compressor power nRoot_P_comp_actl, and the Nth root of the current condenser fan power nRoot_P_oFan_actl are the inputs of the model predictive controller, where N is typically 2; the target compressor speed rpm_comp and the target condenser fan speed rpm_oFan are the outputs of the model predictive controller.

[0077] The air-cooled chiller unit model is the predictive model called by the predictive controller. It can be a linear time-invariant model with a conventional structure, such as a state-space model or a step response model. Its input and output variables are as follows: Figure 6As shown in the figure, the ambient air temperature OAT, chilled water inlet temperature Twater_r, compressor speed rpm_comp, and condenser fan speed rpm_oFan are the input variables of the model. Ambient air temperature OAT and chilled water inlet temperature Twater_r are measurable disturbance variables (i.e., their current actual values ​​can be obtained through detection), while compressor speed rpm_comp and condenser fan speed rpm_oFan are controllable variables. The chilled water inlet and outlet temperature difference ΔTwater, the Nth root of compressor power nRoot_P_comp, and the Nth root of condenser fan power nRoot_P_oFan are the measurable output variables of the model. The parameters of this prediction model can be constructed using mature system identification methods and tools.

[0078] In one specific implementation, the cost function cost_func of the model predictor controller is defined as follows:

[0079]

[0080] Wherein, ΔTwater(i), ΔTwater_tgt(i), nRoot_P_comp(i), and nRoot_P_oFan(i) are the chilled water inlet and outlet temperature difference ΔTwater, the target chilled water inlet and outlet temperature difference ΔTwater_tgt, the Nth root of the compressor power nRoot_P_comp, and the Nth root of the condenser fan power nRoot_P_oFan, respectively, at the i-th prediction time; p is the prediction time domain, wt is the temperature difference weighting coefficient, and wp is the power weighting coefficient, which can be set as needed.

[0081] Optionally, the expansion valve of the above-mentioned air-cooled chiller unit is controlled by a conventional superheat control method, and this application embodiment does not limit this.

[0082] II. See also Figure 7 The diagram shows a system structure schematic of a water-cooled chiller unit. Figure 7As shown, the water-cooled chiller unit includes a compressor, a water-cooled condenser, an expansion valve, and an evaporator; the evaporator is connected to the chilled water inlet pipe and the chilled water outlet pipe, and the chilled water outlet pipe is connected to the chilled water pump; the water-cooled condenser is connected to the cooling water inlet pipe and the cooling water outlet pipe, and the cooling water outlet pipe is connected to the cooling water pump. Temperature sensors can be installed on the chilled water inlet and outlet pipes of the water-cooled chiller unit to detect the chilled water inlet temperature Twater_r and chilled water outlet temperature Twater_o, respectively. The measured values ​​are recorded as the current chilled water inlet temperature Twater_r_actl and the current chilled water outlet temperature Twater_o_actl, respectively. The temperature difference between the chilled water inlet and outlet is represented by ΔTwater, then the current inlet / outlet temperature difference ΔTwater_actl = Twater_r_actl - Twater_o_actl; the target temperature difference ΔTwater_tgt = Twater_r_actl - Twater_o_tgt, where Twater_o_tgt is the target chilled water outlet temperature value, which can generally be taken as an empirical value or an industry-recommended value. Sensors can also be installed on the cooling water inlet pipe of the water-cooled chiller unit to detect the cooling water inlet temperature Tcoolant_r, and the measured value is recorded as the current cooling water inlet temperature Tcoolant_r_actl.

[0083] Based on the description of the foregoing embodiments, the operation control method for a water-cooled chiller unit may include:

[0084] 301. Based on the current cooling water inlet temperature, current chilled water inlet temperature, current chilled water inlet and outlet temperature difference, current compressor power information, current cooling water pump power information, and target chilled water inlet and outlet temperature difference, confirm the target compressor speed and the target cooling water pump speed.

[0085] 302. Control the operation of the compressor according to the target speed of the compressor, and control the operation of the cooling water pump according to the target speed of the cooling water pump.

[0086] Figure 8 This is a schematic diagram of the input and output parameters of a model predictive controller for a water-cooled chiller unit, provided in an embodiment of this application.

[0087] Figure 9 This is a schematic diagram of the input and output variables of a prediction model for a water-cooled chiller unit provided in an embodiment of this application.

[0088] The operation and control methods for water-cooled chillers can be referenced. Figure 1 The specific descriptions of the embodiments shown are not repeated here.

[0089] Specifically, during the operation of the water-cooled chiller unit, the chilled water pump maintains a constant speed. At the same time, a model predictive controller is used to control the compressor speed and the cooling water pump speed. The main method is that the predictive controller can use a mature optimization solver to find the compressor speed and cooling water pump speed values ​​that minimize the loss value. These are used as the target speeds for the compressor and cooling water pump, respectively. This allows the unit power to be controlled while adjusting the temperature difference between the inlet and outlet chilled water, so that the actual value of the chilled water outlet temperature equals the target value, while minimizing the unit power.

[0090] The input and output variables of the model predictive controller are as follows: Figure 8 As shown, the current cooling water inlet temperature Tcoolant_r_actl, the current chilled water inlet temperature Twater_r_actl, the target chilled water inlet and outlet temperature difference ΔTwater_tgt, the current chilled water inlet and outlet temperature difference ΔTwater_actl, the Nth root of the current compressor power nRoot_P_comp_actl, and the Nth root of the current cooling water pump power nRoot_P_oPump_actl are the inputs of the model predictive controller, where N is typically 2; the compressor target speed rpm_comp and the cooling water pump target speed rpm_oPump are the outputs of the model predictive controller.

[0091] The water-cooled chiller unit model is the predictive model called by the predictive controller. It can be a linear time-invariant model with a conventional structure, such as a state-space model or a step response model. Its input and output variables are as follows: Figure 9 As shown in the figure, the cooling water inlet temperature Tcoolant_r, chilled water inlet temperature Twater_r, compressor speed rpm_comp, and cooling water pump speed rpm_oPump are the input variables of the model. Among them, the cooling water inlet temperature Tcoolant_r and chilled water inlet temperature Twater_r are the measurable disturbance variables of the model (that is, the current actual values ​​can be obtained through detection), and the compressor speed rpm_comp and cooling water pump speed rpm_oPump are the controllable variables of the model. The chilled water inlet and outlet temperature difference ΔTwater, the Nth root of the compressor power nRoot_P_comp, and the Nth root of the cooling water pump power nRoot_P_oPump are the measurable output variables of the model. The parameters of this prediction model can be constructed using mature system identification methods and tools.

[0092] In one specific implementation, the cost function cost_func of the model predictor controller is defined as follows:

[0093]

[0094] Wherein, ΔTwater(i), ΔTwater_tgt(i), nRoot_P_comp(i), and nRoot_P_oPump(i) are the chilled water inlet and outlet temperature difference ΔTwater, the target chilled water inlet and outlet temperature difference ΔTwater_tgt, the Nth root of the compressor power nRoot_P_comp, and the Nth root of the cooling water pump power nRoot_P_oPump, respectively, at the i-th prediction time; p is the prediction time domain, wt is the temperature difference weighting coefficient, and wp is the power weighting coefficient, which can be set as needed.

[0095] Optionally, the expansion valve of the above-mentioned water-cooled chiller unit is controlled by a conventional superheat control method, and this application does not limit this.

[0096] In this embodiment, parameters such as the compressor power and condenser fan power (or cooling water pump power) of the chiller unit are directly measured or indirectly calculated. A linear time-invariant model (such as a state-space model or step response model) is established for parameters such as the chilled water inlet and outlet temperature difference, the Nth root of the compressor power, and the Nth root of the condenser fan power (or cooling water pump power). A model predictive control algorithm is then used to control the compressor speed and condenser fan speed (or cooling water pump speed), and the Nth root of the compressor and condenser fan (or cooling water pump) power is incorporated into the predictive control algorithm. The cost function is used to determine the target speed of the compressor and the target speed of the condenser fan (or the target speed of the cooling water pump) by calculating the minimum cost function. This cost function takes into account the power of the compressor and the power of the condenser fan (or the cooling water pump), that is, it takes into account the power of the unit. The chilled water outlet temperature and the power of the unit are adjusted simultaneously. While controlling the actual outlet temperature of the chilled water of the chiller unit to reach the target outlet temperature, the power of the current unit can be controlled. While effectively controlling the outlet temperature of the chilled water of the chiller unit, the power consumption of the unit is reduced, thus achieving energy saving.

[0097] Please see Figure 10 , Figure 10 This is a schematic diagram of the structure of an operation control device for a chiller unit provided in an embodiment of this application, as shown below. Figure 10 As shown, the operation control device 1000 of the chiller unit includes:

[0098] The predictive control module 1010 is used to determine the target speed of the compressor and the target speed of the cooling medium delivery device based on the current cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference.

[0099] The control module 1020 is used to control the operation of the compressor according to the target speed of the compressor, and to control the operation of the cooling medium conveying device according to the target speed of the cooling medium conveying device.

[0100] Optionally, the prediction control module 1010 mentioned above includes a first calculation unit 1011 and a second calculation unit 1012;

[0101] The first calculation unit 1011 is used to calculate the loss value based on the current cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference.

[0102] The second calculation unit 1012 is used to obtain the compressor speed value and the cooling medium conveying device speed value when the loss value is minimized, and use them as the target speed of the compressor and the target speed of the cooling medium conveying device, respectively.

[0103] Optionally, the first computing unit 1011 described above is specifically used for:

[0104] Input the current cooling medium temperature information, the current chilled water inlet temperature value, the compressor speed and the cooling medium delivery device speed into the chiller unit model, and calculate based on the current chilled water inlet and outlet temperature difference value, the current compressor power information and the current cooling medium delivery device power information to output the predicted chilled water inlet and outlet temperature difference value, the predicted compressor power information and the predicted cooling medium delivery device power information.

[0105] The predicted value of the temperature difference between the inlet and outlet of chilled water, the target value of the temperature difference between the inlet and outlet of chilled water, the predicted power information of the compressor, and the predicted power information of the cooling medium conveying device are input into a preset cost function to calculate the loss value under different compressor speeds and cooling medium conveying device speeds.

[0106] Optionally, the aforementioned current compressor power information includes the Nth root of the current compressor power, and the aforementioned current cooling medium delivery device power information includes the Nth root of the current cooling medium delivery device power.

[0107] Optionally, the above-mentioned chiller unit operation control device 1000 further includes an acquisition module 1030, used for:

[0108] The current compressor power and the current cooling medium delivery device power are obtained by using sensors; or,

[0109] The power of the compressor is calculated based on its voltage and current, and the power of the cooling medium delivery device is calculated based on its voltage, current, or speed.

[0110] Optionally, if the cooling medium delivery device is a condenser fan, the cooling medium temperature information is the current ambient air temperature value;

[0111] If the aforementioned cooling medium delivery device is a cooling water pump, the aforementioned cooling medium temperature information is the current cooling water inlet temperature value.

[0112] According to one embodiment of this application, the operation control device 1000 of the above-mentioned chiller unit can perform the following actions: Figure 1 The steps in the illustrated embodiment will not be repeated here. The operation control device 1000 of this chiller unit can be applied to a chiller unit system to realize the above-described operation control method for the chiller unit.

[0113] Based on the description of the above method and device embodiments, this application also provides an electronic device, which can be a water chiller unit. Figure 11 The diagram shown is a structural schematic of an electronic device provided in this application. The electronic device 1100 may include a processor 1101, an input / output device 1102, a memory 1103, and a computer storage medium. The various components within the electronic device can be connected via a bus 1104 or other means.

[0114] A computer storage medium can be stored in the memory 1103 of the electronic device 1100. The computer storage medium is used to store a computer program, which includes program instructions. The processor 1101 is used to execute the program instructions stored in the computer storage medium. The processor (or CPU, Central Processing Unit) is the computing and control core of the electronic device, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or function. In one embodiment, the processor 1101 described above in this application embodiment can be used to perform a series of processes, including... Figure 1 The methods shown involve various steps, etc.

[0115] This application also provides a computer storage medium (memory), which is a memory device in an electronic device used to store programs and data. It is understood that the computer storage medium here can include both built-in storage media in the electronic device and extended storage media supported by the electronic device. The computer storage medium provides storage space that stores the operating system of the electronic device. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device; optionally, it can also be at least one computer storage medium located remotely from the aforementioned processor.

[0116] In one embodiment, a processor may load and execute one or more instructions stored in a computer storage medium to implement the corresponding steps in the above embodiments; specifically, one or more instructions in the computer storage medium may be loaded and executed by a processor, such as... Figure 1 The steps involved in the method shown will not be repeated here.

[0117] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described device and module can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0118] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the division of modules is merely a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. The coupling, direct coupling, or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, apparatuses, or modules, and may be electrical, mechanical, or other forms.

[0119] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0120] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid state disks (SSDs).

Claims

1. A method for controlling the operation of a chiller unit, characterized in that, include: Based on the current cooling medium temperature information, current chilled water inlet temperature value, current chilled water inlet and outlet temperature difference value, current compressor power information, current cooling medium delivery device power information, and target chilled water inlet and outlet temperature difference value, determine the target compressor speed and the target speed of the cooling medium delivery device, including: The loss value is calculated based on the current cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference; Obtaining the compressor speed and cooling medium delivery device speed when the loss value is minimized, and using them as the target speeds for the compressor and cooling medium delivery device, respectively, specifically includes: The current cooling medium temperature, the current chilled water inlet temperature, the compressor speed, and the cooling medium delivery device speed are input into the chiller unit model. Based on the current chilled water inlet / outlet temperature difference, the current compressor power, and the current cooling medium delivery device power, calculations are performed to output predicted chilled water inlet / outlet temperature difference, predicted compressor power, and predicted cooling medium delivery device power. The predicted chilled water inlet / outlet temperature difference, the target chilled water inlet / outlet temperature difference, the predicted compressor power, and the predicted cooling medium delivery device power are input into a preset cost function to calculate the loss value under different compressor speeds and cooling medium delivery device speeds. The compressor speed and cooling medium delivery device speed at which the loss value is minimized are obtained and used as the target compressor speed and the target cooling medium delivery device speed, respectively. The compressor is controlled to operate according to the target speed of the compressor, and the cooling medium delivery device is controlled to operate according to the target speed of the cooling medium delivery device.

2. The operation control method for a chiller unit according to claim 1, characterized in that, The current compressor power information includes the Nth root of the current compressor power, and the current cooling medium delivery device power information includes the Nth root of the current cooling medium delivery device power.

3. The operation control method for a chiller unit according to claim 2, characterized in that, The method further includes: The current compressor power and the current cooling medium delivery device power are obtained by using sensors; or, The current compressor power is calculated based on the compressor's voltage and current, and the current cooling medium delivery device power is calculated based on the voltage, current, or speed of the cooling medium delivery device.

4. The operation control method for a chiller unit according to any one of claims 1-3, characterized in that, If the cooling medium conveying device is a condenser fan, the cooling medium temperature information is the current ambient air temperature value; If the cooling medium delivery device is a cooling water pump, the cooling medium temperature information is the current cooling water inlet temperature value.

5. An operation control device for a chiller unit, characterized in that, include: The predictive control module is used to determine the target speed of the compressor and the target speed of the cooling medium delivery device based on the cooling medium temperature information, the current chilled water inlet temperature value, the current chilled water inlet and outlet temperature difference value, the current compressor power information, the current cooling medium delivery device power information, and the target value of the chilled water inlet and outlet temperature difference. The predictive control module is specifically used for: The current cooling medium temperature information, the current chilled water inlet temperature value, the compressor speed and the cooling medium delivery device speed are input into the chiller unit model, and the current chilled water inlet and outlet temperature difference value, the current compressor power information and the current cooling medium delivery device power information are calculated to output the predicted chilled water inlet and outlet temperature difference value, the predicted compressor power information and the predicted cooling medium delivery device power information. The predicted value of the chilled water inlet and outlet temperature difference, the target value of the chilled water inlet and outlet temperature difference, the predicted power information of the compressor, and the predicted power information of the cooling medium conveying device are input into a preset cost function to calculate the loss value under different compressor speeds and cooling medium conveying device speeds. The compressor speed and the cooling medium delivery device speed are obtained when the loss value is minimized, and are used as the target speed of the compressor and the target speed of the cooling medium delivery device, respectively. The control module is used to control the compressor according to the target speed of the compressor and to control the cooling medium delivery device according to the target speed of the cooling medium delivery device.

6. An electronic device, characterized in that, It includes a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps of the chiller unit operation control method as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The system contains a computer program that, when executed by a processor, causes the processor to perform the steps of the chiller unit operation control method as described in any one of claims 1 to 4.

Images