Variable frequency air conditioner load adjustable capacity evaluation method and device

Abstract

The invention provides a variable frequency air conditioner load adjustable capacity evaluation method and device, and relates to the technical field of adjustable capacity evaluation. The method comprises the steps that firstly, modeling is conducted on a single variable frequency air conditioner load based on an equivalent thermal parameter model, and the dynamic relation between the temperature and the air conditioner refrigerating capacity is reflected; then, a variable set of a variable frequency air conditioner load cluster is defined, a variable frequency air conditioner load cluster model is represented, temperature setting or switching operation is conducted on single variable frequency air conditioner loads in the variable frequency air conditioner load cluster model, and the variable frequency air conditioner loads participate in demand response; and finally determining the regulation duration of the variable frequency air conditioner load participating in the demand response under the condition of considering the comfortable temperature, and evaluating the adjustable capacity of the variable frequency air conditioner load. According to the invention, on the premise of ensuring the comfort of the user, a certain adjustable capability is provided, and the precision of the adjustable capacity evaluation result is high; the economical efficiency can be improved while the comfort level of a user is met.

Description

Technical Field

[0001] The present invention relates to the technical field of adjustable capacity evaluation, and particularly to a method and device for evaluating the adjustable capacity of a variable-frequency air-conditioning load. Background Art

[0002] The demand response (DR) technology provides a good solution to address the uncertainty of new energy output, improve the economy and environmental friendliness of the power grid system. Through the DR technology, the electricity consumption behavior of the load can be flexibly regulated, equivalently providing a certain adjustable capacity, thereby enriching the dispatchable resources of the power grid. On the load side, especially the inverter air conditioning load (IACL) participating in DR has great advantages: (1) Large capacity, especially accounting for a high proportion of the total load in summer; (2) Having the characteristics of load virtual energy storage, the inherent thermal inertia of the building makes the inverter air conditioning load become virtual energy storage; (3) The human body can accept a relatively large temperature comfort range, and its flexible adjustment does not affect user comfort; (4) Fast response, enabling precise control.

[0003] Traditional evaluation methods for inverter air conditioning loads mostly focus on static calculations, ignoring the dynamic changes and the actual needs of user comfort. That is, the size of the adjustable capacity is not considered on the premise of the response time, which is not feasible in actual operation. Only the adjustment under the set value of the user's temperature is considered, and its adjustable ability is limited. In addition, the modeling process of traditional evaluation methods is complex, and the parameter solution is relatively difficult, making it difficult to accurately express its non-linear relationship, resulting in low accuracy of the evaluation results. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and device for evaluating the adjustable capacity of a variable-frequency air-conditioning load, which are used to solve the problems that the existing evaluation methods for variable-frequency air-conditioning loads are not feasible and the accuracy of the evaluation results of the adjustable capacity is low, etc. Under the premise of ensuring user comfort, a certain adjustable ability is provided, providing a method support for calculating the adjustable capacity of the cluster, and the accuracy of the evaluation results of the adjustable capacity is high; the economy can be improved while meeting user comfort.

[0005] To achieve the above purpose, in the first aspect, the present invention provides a method for evaluating the adjustable capacity of a variable-frequency air-conditioning load, including: Modeling the single-unit variable-frequency air-conditioning load based on an equivalent thermal parameter model to reflect the dynamic relationship between temperature and air-conditioning cooling capacity; Define a variable set for the variable-frequency air-conditioning load cluster, characterize the variable-frequency air-conditioning load cluster model, perform temperature setting or switching operations on the individual variable-frequency air-conditioning loads in the variable-frequency air-conditioning load cluster model to change the power of the individual variable-frequency air-conditioning loads, and further affect the overall power of the variable-frequency air-conditioning load cluster, so as to enable the variable-frequency air-conditioning load to participate in demand response; Quantify the influence of temperature on human comfort based on the predicted mean vote value, determine the regulation duration for the variable-frequency air-conditioning load to participate in demand response considering temperature comfort, calculate the operating frequency and power of the variable-frequency air-conditioning load according to the change in cooling capacity during the regulation duration, and then evaluate the adjustable capacity of the variable-frequency air-conditioning load.

[0006] According to an adjustable capacity evaluation method for a variable-frequency air-conditioning load provided by the present invention, the dynamic relationship between temperature and air-conditioning cooling capacity is:

[0007]

[0008] In the formula, is the cooling capacity at time t, is the cooling capacity at time t + 1, is the indoor temperature at time is the indoor temperature at time t + 1, is the outdoor temperature at time is the outdoor temperature at time t + 1; is the time interval between time t + 1 and time t; C and R are both parameters; is the start / stop state of the air conditioner at time is the energy efficiency ratio of the air conditioner; is the rated power of the air conditioner; is the indoor temperature change range when the air conditioner operates stably.

[0009] According to an adjustable capacity evaluation method for a variable-frequency air-conditioning load provided by the present invention, the start / stop state of the air conditioner is:

[0010] In the formula, is the set temperature, is the temperature control threshold of the air conditioner, is the start / stop state of the air conditioner at time

[0011] According to an adjustable capacity evaluation method for a variable-frequency air-conditioning load provided by the present invention, the variable-frequency air-conditioning load cluster model includes:

[0012]

[0013] In the formula, are respectively the air conditioner on - cluster and the air conditioner off - cluster at the and are respectively the th air conditioner with the on and off states at the is the number of air conditioners turned on, is the number of air conditioners turned off; The power of the variable - frequency air - conditioner load cluster is:

[0014] In the formula, is the power of the variable - frequency air - conditioner load cluster at the is the power of the th air conditioner turned on at the The temperature set value and temperature threshold of the variable - frequency air - conditioner load cluster are:

[0015]

[0016]

[0017] In the formula, and are respectively the temperature set value and temperature threshold of the variable - frequency air - conditioner load cluster at the and are respectively the temperature set value and temperature threshold of the th air conditioner at the N is the total number of air conditioners in the variable - frequency air - conditioner load cluster.

[0018] According to a method for evaluating the adjustable capacity of a variable - frequency air - conditioner load provided by the present invention, quantifying the influence of temperature on human comfort based on the predicted mean vote value, includes: Determining the temperature comfort zone of the indoor temperature according to the magnitude of the predicted mean vote value.

[0019] According to a method for evaluating the adjustable capacity of a variable - frequency air - conditioner load provided by the present invention, quantifying the influence of temperature on human comfort based on the predicted mean vote value, specifically includes: Determining the level reflecting human comfort according to the magnitude of the predicted mean vote value, and obtaining the corresponding range of the temperature comfort zone based on the predetermined specification according to the level.

[0020] An adjustable capacity evaluation method for variable-frequency air-conditioning load, according to the change in refrigerating capacity under the regulation duration, calculates the operating frequency and power of the variable-frequency air-conditioning load, and further evaluates the adjustable capacity of the variable-frequency air-conditioning load, including: According to the reduced refrigerating capacity under the regulation duration, calculate the operating frequency and power of the variable-frequency air-conditioning load, and further evaluate the downward adjustable capacity of the variable-frequency air-conditioning load; according to the increased refrigerating capacity under the regulation duration, calculate the operating frequency and power of the variable-frequency air-conditioning load, and further evaluate the upward adjustable capacity of the variable-frequency air-conditioning load; evaluate the range of the adjustable capacity of the variable-frequency air-conditioning load according to the downward adjustable capacity and the upward adjustable capacity.

[0021] An adjustable capacity evaluation method for variable-frequency air-conditioning load, according to the reduced refrigerating capacity under the regulation duration, calculates the operating frequency and power of the variable-frequency air-conditioning load, and further evaluates the downward adjustable capacity of the variable-frequency air-conditioning load, including: Assume that the outdoor temperature of the th system in the variable-frequency air-conditioning load cluster remains constant at , starts regulation at time t and ends regulation at time t + 1, the temperature comfort zone is , the indoor temperature after regulation is the maximum comfort value , and the outdoor temperature is constant during the regulation duration; Then the regulation duration considering demand response under temperature comfort is:

[0022] In the formula, is the refrigerating capacity at the lowest frequency of the air conditioner; are all parameters; ; The reduced refrigerating capacity under this regulation duration is:

[0023] In the formula, is the indoor temperature set value at time t; Furthermore, calculate the operating frequency and power of the variable-frequency air-conditioning load as:

[0024]

[0025] In the formula, is the operating frequency of the variable-frequency air-conditioning load, is the power of the variable-frequency air-conditioning load; are the curve fitting coefficients of the operating frequency and refrigerating capacity of the variable-frequency air-conditioning load respectively; They are the curve fitting coefficients of the working frequency and power of the variable-frequency air-conditioning load respectively; The variable-frequency air-conditioning load is at At the moment, it needs to be in a steady state. Then the downward adjustable capacity of the variable-frequency air-conditioning load is:

[0026]

[0027] In the formula, is the downward adjustable capacity of the variable-frequency air-conditioning load at time t; is the stable operating power of the variable-frequency air-conditioning load; is the power corresponding to the variable-frequency air-conditioning load at the set frequency at time t; is The power corresponding to the variable-frequency air-conditioning load at the set frequency at the moment.

[0028] According to an adjustable capacity evaluation method for a variable-frequency air-conditioning load provided by the present invention, based on the increased cooling capacity during the regulation duration, the working frequency and power of the variable-frequency air-conditioning load are calculated, and then the upward adjustable capacity of the variable-frequency air-conditioning load is evaluated, including: Assume that the outdoor temperature of the th system in the variable-frequency air-conditioning load cluster is constantly , the regulation starts at time t and ends at time t + 1, the temperature comfort zone is , and the indoor temperature after the regulation ends is the minimum comfort value , and the outdoor temperature is constant during the regulation duration; Then the increased cooling capacity during this regulation duration is:

[0029] Furthermore, the working frequency and power of the variable-frequency air-conditioning load are calculated as:

[0030]

[0031] The variable-frequency air-conditioning load is at At the moment, it needs to be in a steady state. Then the upward adjustable capacity of the variable-frequency air-conditioning load is:

[0032] In the formula, is the upward adjustable capacity of the variable-frequency air-conditioning load at time t.

[0033] In the second aspect, the present invention provides an adjustable capacity evaluation device for a variable-frequency air-conditioning load, including: A modeling unit, which is used to model the single-variable frequency air-conditioning load based on an equivalent thermal parameter model, and reflect the dynamic relationship between temperature and air-conditioning cooling capacity; A response unit, which is used to define a variable set of the variable-frequency air-conditioning load cluster, characterize the variable-frequency air-conditioning load cluster model, perform temperature setting or switching operations on the single-variable frequency air-conditioning load in the variable-frequency air-conditioning load cluster model, so as to change the power of the single-variable frequency air-conditioning load, and further affect the overall power of the variable-frequency air-conditioning load cluster, and realize the participation of the variable-frequency air-conditioning load in demand response; An evaluation unit, which is used to quantify the influence of temperature on human comfort based on the predicted mean vote value, determine the regulation duration for the variable-frequency air-conditioning load to participate in demand response considering temperature comfort, calculate the working frequency and power of the variable-frequency air-conditioning load according to the change in cooling capacity during the regulation duration, and further evaluate the adjustable capacity of the variable-frequency air-conditioning load.

[0034] The technical solution of the present invention at least has the following technical effects: An adjustable capacity evaluation method and device for a variable-frequency air-conditioning load provided by the present invention. First, a single-variable frequency air-conditioning load is modeled based on an equivalent thermal parameter model to reflect the dynamic relationship between temperature and air-conditioning cooling capacity; then, a variable set of the variable-frequency air-conditioning load cluster is defined to characterize the variable-frequency air-conditioning load cluster model, and temperature setting or switching operations are performed on the single-variable frequency air-conditioning load in the variable-frequency air-conditioning load cluster model to change the power of the single-variable frequency air-conditioning load, and further affect the overall power of the variable-frequency air-conditioning load cluster, so as to realize the participation of the variable-frequency air-conditioning load in demand response; finally, the influence of temperature on human comfort is quantified based on the predicted mean vote value, the regulation duration for the variable-frequency air-conditioning load to participate in demand response considering temperature comfort is determined, and the working frequency and power of the variable-frequency air-conditioning load are calculated according to the change in cooling capacity during the regulation duration, and further the adjustable capacity of the variable-frequency air-conditioning load is evaluated. The present invention not only provides a certain adjustable ability on the premise of ensuring user comfort, but also avoids the problem that the adjustable durations of each air-conditioning are different due to factors such as parameters and working conditions, thus providing a method support for calculating the adjustable capacity of the cluster; it can improve the economy while meeting user comfort. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] In the drawings: Figure 1 It is a schematic diagram of the first-order equivalent thermal parameter model of the single-variable frequency air-conditioning load of the present invention; Figure 2 Schematic diagram of the response process of the variable-frequency air-conditioning load of the present invention participating in regulation and control; Figure 3 Outdoor temperature curve within 24 hours in the specific embodiment 2 of the present invention; Figure 4 Operating power curve of the variable-frequency air-conditioning load cluster at each moment in the specific embodiment of the present invention; Figure 5 Flow chart of the adjustable capacity evaluation method for the variable-frequency air-conditioning load of the present invention. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts fall within the scope of protection of the present invention.

[0038] The following will describe in detail some embodiments of the present invention with reference to the accompanying drawings. Without conflict, the embodiments described below and the features in the embodiments can be combined with each other.

[0039] In order to address the problems mentioned in the background art, the present invention uses the response duration and the regulated power amount of the variable-frequency air-conditioning load as evaluation indicators, obtains the corresponding temperature operating range through the comfort constraint of users, and changes the temperature set value and the on-off control state within this temperature operating range. Then, from the perspective of user comfort, the present invention makes full use of the adjustable means of the IACL cluster in the power grid, considers the response strategy of the IACL cluster, and evaluates the adjustable capacity of the IACL cluster.

[0040] Please refer to Figure 5 , the embodiment of the present invention provides an adjustable capacity evaluation method for a variable-frequency air-conditioning load, including: Step 1, model the single-variable-frequency air-conditioning load based on the Equivalent thermal parameters (ETP) model to reflect the dynamic relationship between temperature and air-conditioning cooling capacity; Specifically, for the modeling of the variable-frequency air-conditioning load using the start-stop control method, a first-order equivalent thermal parameter model commonly used in engineering is adopted. It should be emphasized that the ETP model is mainly used for the air-conditioning modeling of residential and small and medium-sized commercial buildings. Using the equivalent heat capacity C, equivalent thermal resistance R of the room, outdoor temperature T in , indoor temperature T out and cooling capacity Q ACDescribe the thermal characteristics parameters, such as Figure 1 As shown, simplify it to a first-order equation to obtain the room temperature and the refrigerating capacity The relationship is:

[0041] Use the recurrence relation for transformation and arrangement to obtain:

[0042] The following equation is the function of the relationship between the refrigerating capacity and the temperature:

[0043] In the above equation, is the refrigerating capacity at time t, is the refrigerating capacity at time t + 1, is the indoor temperature at the moment, is the indoor temperature at time t + 1, is the outdoor temperature at the moment, is the outdoor temperature at time t + 1; is the time interval between time t + 1 and time t; C and R are both parameters, and their values are related to the room volume, specific heat capacity of air, and thermal conductivity; is the start-stop state of the air conditioner at the moment; is the energy efficiency ratio of the air conditioner; is the rated power of the air conditioner; is the range of indoor temperature change during the stable operation of the air conditioner, and the relationship among the start-stop state of the air conditioner, the set temperature and the set temperature boundary is:

[0044] In the formula, is the temperature control threshold of the air conditioner, is the start-stop state of the air conditioner at the moment.

[0045] Step 2: Define the variable set of the variable-frequency air conditioner load cluster to characterize the variable-frequency air conditioner load cluster model, and perform temperature setting or switching operations on the single variable-frequency air conditioner load in the variable-frequency air conditioner load cluster model to change the power of the single variable-frequency air conditioner load, thereby affecting the overall power of the variable-frequency air conditioner load cluster and realizing the participation of the variable-frequency air conditioner load in demand response; Specifically, the variable-frequency air conditioner load cluster contains a large number of devices and has a complex internal process, making it difficult to accurately describe the power and temperature response processes. The present invention characterizes the variable-frequency air conditioner load cluster model indirectly by defining the variable set of the variable-frequency air conditioner load cluster.

[0046] At moment, the variable-frequency air-conditioning load cluster can be divided into an air-conditioning-on cluster and an air-conditioning-off cluster according to its switch state, expressed as:

[0047]

[0048] In the formula, are respectively the air-conditioning-on cluster and the air-conditioning-off cluster at and are respectively the th air conditioner with the on and off states at is the number of air conditioners turned on, is the number of air conditioners turned off; , N is the total number of air conditioners in the variable-frequency air-conditioning load cluster. The power of the variable-frequency air-conditioning load cluster is the sum of the power consumptions of each air conditioner in the air-conditioning-on cluster:

[0049] In the formula, is the power of the variable-frequency air-conditioning load cluster at is the power of the th air conditioner turned on at

[0050] Similarly, the cluster temperature set value and the temperature threshold at moment can be expressed as:

[0051]

[0052] In the formula, and are respectively the temperature set value and the temperature threshold of the th air conditioner at

[0053] Figure 2 shows the response process when the variable-frequency air-conditioning load participates in demand response, which includes three different control methods (switch control, temperature regulation, and hybrid control). The curve in the temperature range is the operating temperature curve in the cooling mode. At At a certain moment, it starts to participate in the response, and the air conditioner status is controlled by a switch to transition from area A to area B. When the temperature drops below the lower limit, the air conditioner shuts down. At At a certain moment, when the temperature crosses the set lower limit, the temperature set value is changed through temperature adjustment, transitioning from area B to area C. The air conditioner that was about to shut down originally continues to operate until it reaches the new temperature lower limit and then shuts down. At At a certain moment, hybrid control is performed (changing both the temperature set value and the switch status simultaneously), the temperature range transitions to area D, and the air conditioner shuts down when the temperature drops to the new lower limit.

[0054] Step 3: Quantify the impact of temperature on human comfort based on the predicted mean vote value, determine the regulation duration for the variable-frequency air conditioner load to participate in demand response considering temperature comfort, calculate the working frequency and power of the variable-frequency air conditioner load according to the change in cooling capacity during the regulation duration, and then evaluate the adjustable capacity of the variable-frequency air conditioner load.

[0055] Specifically, the user's perception of the ambient temperature is characterized by thermal comfort. The predicted mean vote (PMV) is used as a comprehensive index, which includes multiple parameters such as indoor temperature, human clothing, human activity status, and humidity that affect human comfort. The PMV value is quantified between [-3, 3], and seven-level indicators are used to indicate the human thermal sensation. PMV values of -3, -2, and -1 represent cold, cool, and slightly cool respectively, PMV values of 3, 2, and 1 represent hot, warm, and slightly warm respectively, and when the PMV value is 0, it indicates that the human body is most comfortable.

[0056] PMV value The calculation method is as follows:

[0057] In the formula, is the human metabolic rate; is the efficiency when the human body performs daily activities; is the water vapor pressure in the air; is the human clothing coefficient; is the clothing surface temperature; is the radiant temperature; is the heat transfer coefficient.

[0058] According to the predetermined specifications, such as the relevant content of the "Design Code for Heating, Ventilation and Air Conditioning of Civil Buildings", when , that is, when reaching the II-level comfort level, the heating temperature range is , on this premise in the present invention, a constraint range is provided for the indoor temperature, that is, in step 3, the influence of temperature on human comfort is quantified based on the predicted mean vote value, including: determining the temperature comfort zone of the indoor temperature according to the magnitude of the predicted mean vote value. In some embodiments, it specifically includes: determining the level reflecting human comfort according to the magnitude of the predicted mean vote value, and obtaining the range of the corresponding temperature comfort zone based on the predetermined specification. For example, when the range of the predicted mean vote value is , the level is slightly cool, most comfortable or slightly warm at this time, reaching the II-level comfort, and the range of the temperature comfort zone at this moment is .

[0059] Assume that the outdoor temperature of the th system in the variable-frequency air-conditioning load cluster is constant at , starts to be regulated at time t and ends at time t + 1. The temperature comfort zone is , and the indoor temperature after the regulation ends is the maximum comfort value , and the outdoor temperature is constant during the regulation duration.

[0060] Then the regulation duration considering demand response under temperature comfort is:

[0061] In the formula, is the cooling capacity at the lowest frequency of the air conditioner; are all parameters, and their values are related to the room volume, specific heat capacity of air, and thermal conductivity; ; in the variable-frequency air-conditioning load cluster, the regulation durations of IACLs with different thermal parameters will be different, which brings inconvenience to the evaluation of the adjustable ability of the variable-frequency air-conditioning load cluster. Therefore, the present invention unifies the regulation duration of the IACL cluster with different equivalent parameters to .

[0062] The reduced cooling capacity under this regulation duration can be obtained by the following formula:

[0063] In the formula, is the indoor temperature set value at time t.

[0064] Furthermore, the operating frequency and power of the variable-frequency air-conditioning load are calculated:

[0065]

[0066] In the formula, is the curve fitting coefficient of the operating frequency and the cooling capacity; is the curve fitting coefficient of working frequency and power. The variable-frequency air-conditioning load participating in the response needs to be in a steady state at moment, and the downward adjustable capacity of the variable-frequency air-conditioning load at this time is expressed as:

[0067]

[0068] In the formula, is the stable operating power of the variable-frequency air-conditioning load; is the power corresponding to the variable-frequency air-conditioning load at the set frequency at time t, is the power corresponding to the variable-frequency air-conditioning load at the set frequency at

[0069] Similarly, when the indoor temperature is the minimum comfort value after the regulation ends, then the increased cooling capacity under this regulation duration is:

[0070] Furthermore, the working frequency and power of the variable-frequency air-conditioning load are calculated as:

[0071]

[0072] The variable-frequency air-conditioning load needs to be in a steady state at moment, then the upward adjustable capacity of the variable-frequency air-conditioning load is:

[0073] In the formula, is the upward adjustable capacity of the variable-frequency air-conditioning load at time t.

[0074] Then, the adjustable capacity range of the variable-frequency air-conditioning load is evaluated based on the downward adjustable capacity and the upward adjustable capacity.

[0075] Based on the same inventive concept, another embodiment of the present invention provides an adjustable capacity evaluation device for a variable-frequency air-conditioning load. This device corresponds to the method of the foregoing embodiment. This device includes: A modeling unit, used to model the single variable-frequency air-conditioning load based on an equivalent thermal parameter model to reflect the dynamic relationship between temperature and air-conditioning cooling capacity; A response unit, used to define a variable set of the variable-frequency air-conditioning load cluster, characterize the variable-frequency air-conditioning load cluster model, perform temperature setting or switching operations on the single variable-frequency air-conditioning load in the variable-frequency air-conditioning load cluster model to change the power of the single variable-frequency air-conditioning load, and further affect the overall power of the variable-frequency air-conditioning load cluster, so as to realize the participation of the variable-frequency air-conditioning load in demand response; An evaluation unit is used to quantify the impact of temperature on human comfort based on the predicted average evaluation value, determine the regulation duration for the variable-frequency air conditioner load participating in demand response considering temperature comfort, calculate the operating frequency and power of the variable-frequency air conditioner load according to the change in refrigerating capacity during the regulation duration, and then evaluate the adjustable capacity of the variable-frequency air conditioner load.

[0076] The following is a specific embodiment of the present invention.

[0077] According to the adjustable capacity evaluation method proposed by the present invention, a variable-frequency air conditioner aggregation model is constructed in Matlab. It is assumed that 1000 air conditioners in a certain area have signed an incentive agreement and are divided into four groups, jointly forming a cluster. The number of air conditioners in each group and the distribution of each parameter are shown in Table 1.

[0078] Table 1. Number of air conditioners in each group and distribution of each parameter

[0079] Assume that the set temperature of the user is 24°C, and the comfort interval is [22°C, 26°C]. The outdoor temperature curve within 24 hours is as Figure 3 shown. By obtaining the self-performance parameters of each air conditioner, including the maximum and minimum refrigerating capacities and the corresponding refrigerating powers, etc., the upward and downward adjustable capacities that the entire cluster can provide are further obtained. Combining the stable operating powers of each adjustable variable-frequency air conditioner load, the operating power range of each time period of the cluster can be further known, as Figure 4 shown.

[0080] It can be seen from Figure 4 that at the 14th moment, the expected power consumption of the cluster is the largest, which is 1530 kW, and the adjustable range is also the largest, which is [1620 kW, 1440 kW]; at the 24th moment, the expected power consumption of the cluster is the smallest, which is 1020 kW, and the adjustable range is also the smallest, which is [960 kW, 1080 kW]. Finally, a comparison is made between the traditional method without considering user comfort, the traditional method considering comfort, and the method of the present invention. The comparison of the adjustable capabilities of the variable-frequency air conditioner load under different methods within a certain response time with a control period of 15 minutes is shown in Table 2.

[0081] Table 2. Comparison of adjustable capabilities of variable-frequency air conditioner load under different methods

[0082] As can be seen from Table 2, there are significant differences in the adjustable capacity provided by variable-frequency air-conditioning loads under different evaluation methods. Under the traditional evaluation method without considering user comfort, the operating power at this time is 978 kW, and the maximum adjustable capacity that can be provided is 348 kW. However, there is no limit on the air-conditioning regulation duration in this scenario, and the indoor temperature will exceed the temperature comfort range during the actual regulation process, seriously affecting the user experience. Under the traditional evaluation method considering user comfort, the air conditioner can also provide an adjustable capacity of 348 kW, but the allowable regulation duration under the premise of ensuring user comfort is only 4 minutes, making it difficult to achieve large-scale regulation of air conditioners. Under the evaluation method of the present invention considering user comfort, the operating power of the air conditioner at the end of the 15-minute regulation period is 1248 kW, with an adjustable capacity of 78 kW. Compared with the previous two methods, although the adjustable capacity of the air conditioner is reduced under this method, it provides the possibility for large-scale regulation of air conditioners under different working conditions.

[0083] In summary, the adjustable capacity evaluation method and device for variable-frequency air-conditioning loads provided by the present invention not only provide a certain adjustable capacity under the premise of ensuring user comfort, but also avoid the problem of different regulation durations caused by factors such as parameters and working conditions of each air conditioner, thus providing a method support for the calculation of the adjustable capacity of the cluster. And taking the response duration and response power as evaluation indicators, different evaluation methods are used for comparative analysis. Through numerical examples, it is shown that the method proposed by the present invention is more superior, and the adjustable range of the variable-frequency air-conditioning load cluster capacity is obtained.

[0084] Those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and the practice of the embodiments disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common general knowledge or conventional technical means in the technical field not disclosed by the present invention. It should be understood that the present invention is not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. An adjustable capacity evaluation method for a variable frequency air conditioner load, characterized in that, Including: Modeling the single-unit variable-frequency air-conditioning load based on an equivalent thermal parameter model to reflect the dynamic relationship between temperature and air-conditioning cooling capacity; Defining a variable set of the variable-frequency air-conditioning load cluster to characterize the variable-frequency air-conditioning load cluster model, performing temperature setting or switching operations on the single-unit variable-frequency air-conditioning load in the variable-frequency air-conditioning load cluster model to change the power of the single-unit variable-frequency air-conditioning load, thereby affecting the overall power of the variable-frequency air-conditioning load cluster and realizing the participation of the variable-frequency air-conditioning load in demand response; Quantifying the impact of temperature on human comfort based on the predicted mean vote value, determining the regulation duration for the variable-frequency air-conditioning load to participate in demand response considering temperature comfort, calculating the operating frequency and power of the variable-frequency air-conditioning load according to the change in cooling capacity during the regulation duration, and then evaluating the adjustable capacity of the variable-frequency air-conditioning load.

2. The adjustable capacity evaluation method for the variable-frequency air-conditioning load according to claim 1, characterized in that The dynamic relationship between the temperature and the air-conditioning cooling capacity is: Wherein, is the refrigerating capacity at time t, is the refrigerating capacity at time t + 1, is the indoor temperature at time is the indoor temperature at time t + 1, is the outdoor temperature at time is the outdoor temperature at time t + 1; is the time interval between time t + 1 and time t; C and R are both parameters; is the start-stop state of the air conditioner at time is the energy efficiency ratio of the air conditioner; is the rated power of the air conditioner; is the range of indoor temperature change during stable operation of the air conditioner.

3. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 2, wherein The start-stop state of the air-conditioning is: Wherein, is the set temperature, is the temperature control threshold of the air conditioner, is the start / stop state of the air conditioner at time 4. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 3, characterized in that The variable-frequency air-conditioning load cluster model includes: Wherein, are respectively the air conditioner on-cluster and the air conditioner off-cluster at the and are respectively the th air conditioner in the on state and the off state at the is the number of air conditioners in the on state, is the number of air conditioners in the off state; The power of the variable-frequency air-conditioning load cluster is: In the formula, is the power of the variable-frequency air-conditioning load cluster at time is the power of the th air conditioner turned on at time The temperature set value and temperature threshold of the variable-frequency air-conditioning load cluster are: In the formula, and are respectively the temperature set value and the temperature threshold of the variable-frequency air-conditioning load cluster at time and are respectively the temperature set value and the temperature threshold of the th air conditioner at time N is the total number of air conditioners in the variable-frequency air-conditioning load cluster.

5. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 4, characterized in that The quantifying the impact of temperature on human comfort based on the predicted mean vote value includes: Determining the temperature comfort zone of the indoor temperature according to the magnitude of the predicted mean vote value.

6. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 5, wherein The quantifying the impact of temperature on human comfort based on the predicted mean vote value specifically includes: Determining the level reflecting human comfort according to the magnitude of the predicted mean vote value, and obtaining the range of the corresponding temperature comfort zone based on a predetermined specification according to the level.

7. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 5, wherein The calculating the operating frequency and power of the variable-frequency air-conditioning load according to the change in cooling capacity during the regulation duration, and then evaluating the adjustable capacity of the variable-frequency air-conditioning load includes: Calculating the operating frequency and power of the variable-frequency air-conditioning load according to the reduced cooling capacity during the regulation duration, and then evaluating the downward adjustable capacity of the variable-frequency air-conditioning load; calculating the operating frequency and power of the variable-frequency air-conditioning load according to the increased cooling capacity during the regulation duration, and then evaluating the upward adjustable capacity of the variable-frequency air-conditioning load; evaluating the range of the adjustable capacity of the variable-frequency air-conditioning load according to the downward adjustable capacity and the upward adjustable capacity.

8. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 7, characterized in that, The calculating the operating frequency and power of the variable-frequency air-conditioning load according to the reduced cooling capacity during the regulation duration, and then evaluating the downward adjustable capacity of the variable-frequency air-conditioning load includes: Assume that the outdoor temperature of the th system in the variable-frequency air-conditioning load cluster is constant at . The regulation starts at time t and ends at time t + 1. The temperature comfort zone is . After the regulation ends, the indoor temperature is the maximum comfort value . The outdoor temperature is constant during the regulation period; Then the regulation duration for demand response considering temperature comfort is: In the formula, is the cooling capacity at the lowest frequency of the air conditioner; are all parameters; ; The reduced cooling capacity during this regulation duration is: Wherein, is the indoor temperature set value at time t; And then calculating the operating frequency and power of the variable-frequency air-conditioning load as: In the formula, is the operating frequency of the variable-frequency air-conditioning load, is the power of the variable-frequency air-conditioning load; are the curve fitting coefficients of the operating frequency and the cooling capacity of the variable-frequency air-conditioning load respectively; are the curve fitting coefficients of the operating frequency and the power of the variable-frequency air-conditioning load respectively; The variable-frequency air-conditioning load needs to be in a steady state at the moment, and the downward adjustable capacity of the variable-frequency air-conditioning load is as follows: In the formula, is the downward adjustable capacity of the variable-frequency air-conditioning load at time t; is the stable operating power of the variable-frequency air-conditioning load; is the power corresponding to the variable-frequency air-conditioning load at the set frequency at time t; is the power corresponding to the variable-frequency air-conditioning load at the set frequency at time 9. The adjustable capacity evaluation method for the variable frequency air conditioner load according to claim 8, characterized in that The calculating the operating frequency and power of the variable-frequency air-conditioning load according to the increased cooling capacity during the regulation duration, and then evaluating the upward adjustable capacity of the variable-frequency air-conditioning load includes: Assume that the outdoor temperature of the th system in the variable-frequency air-conditioning load cluster is constant at . Regulation starts at time t and ends at time t + 1. The temperature comfort zone is . After the regulation ends, the indoor temperature is the minimum comfort value . The outdoor temperature is constant during the regulation duration; Then the increased cooling capacity during this regulation duration is: And then calculating the operating frequency and power of the variable-frequency air-conditioning load as: The variable-frequency air-conditioning load needs to be in a steady state at the moment, and the upward adjustable capacity of the variable-frequency air-conditioning load is as follows: In the formula, is the upward adjustable capacity of the variable-frequency air conditioner load at time t.

10. An adjustable capacity evaluation device for a variable frequency air conditioner load, characterized in that, Including: A modeling unit for modeling the single-unit variable-frequency air-conditioning load based on an equivalent thermal parameter model to reflect the dynamic relationship between temperature and air-conditioning cooling capacity; A response unit, which is used to define a set of variables of a variable-frequency air-conditioning load cluster, characterize the variable-frequency air-conditioning load cluster model, perform temperature setting or switching operations on the individual variable-frequency air-conditioning loads in the variable-frequency air-conditioning load cluster model to change the power of the individual variable-frequency air-conditioning loads, and thus affect the overall power of the variable-frequency air-conditioning load cluster, so as to enable the variable-frequency air-conditioning load to participate in demand response; An evaluation unit, which is used to quantify the impact of temperature on human comfort based on the predicted mean vote value, determine the regulation duration for the variable-frequency air-conditioning load to participate in demand response considering temperature comfort, calculate the operating frequency and power of the variable-frequency air-conditioning load according to the change in cooling capacity during the regulation duration, and then evaluate the adjustable capacity of the variable-frequency air-conditioning load.

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