Voltage active support control method and device for variable frequency air conditioner

Abstract

Embodiments of the present application relate to a voltage active support control method and device for a variable frequency air conditioner, comprising: establishing a variable frequency air conditioner model; simulating dynamic characteristics of the variable frequency air conditioner under multiple voltage states based on the variable frequency air conditioner model; and equivalent constant power load of the variable frequency air conditioner to constant torque load based on the dynamic characteristics, for voltage active support control. Thus, the variable frequency air conditioner is modeled, then the dynamic voltage characteristics of the air conditioner under different voltage faults are simulated, and the constant power load of the variable frequency air conditioner is further equivalent to the constant torque load for voltage drop, voltage interruption and voltage recovery and other different voltage conditions, to realize voltage active support control, fully play the role of intelligent load side control, and relieve the impact on the power grid by improving the load characteristics of the variable frequency air conditioner.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power systems, and in particular to a voltage active support control method and device for a variable frequency air conditioner. Background Technology

[0002] With the improvement of people's living standards, the proportion of temperature-controlled loads, mainly air conditioning loads, is constantly increasing. Statistics show that global air conditioning and electric fan consumption accounts for more than one-fifth of the world's total electricity consumption. In July 1987, a shocking voltage collapse occurred in Tokyo, Japan. During the voltage drop, air conditioning loads absorbed a large amount of reactive current, increasing load admittance and accelerating the voltage collapse. Therefore, load characteristics are the most critical and direct factor affecting voltage stability. As the market share of inverter air conditioners increases, current research mostly focuses on fixed-frequency air conditioners. However, with the new air conditioning energy efficiency standard (GB 21455—2019) significantly raising the energy efficiency threshold, research on control schemes to improve the impact on grid voltage stability, especially for inverter air conditioners, is becoming increasingly urgent, aiming to fully explore and utilize their response potential. Summary of the Invention

[0003] In view of this, in order to solve the above-mentioned technical problems or some of the technical problems, the present invention provides a voltage active support control method and device for variable frequency air conditioners.

[0004] In a first aspect, embodiments of the present invention provide a voltage active support control method for a variable frequency air conditioner, comprising:

[0005] Establish a variable frequency air conditioner model;

[0006] The dynamic characteristics of a variable frequency air conditioner under various voltage conditions are simulated based on the aforementioned variable frequency air conditioner model.

[0007] Based on the aforementioned dynamic characteristics, the constant power load of the variable frequency air conditioner is equivalent to a constant torque load for active voltage support control.

[0008] In one possible implementation, the method further includes:

[0009] The permanent magnet synchronous motor model is described by voltage equation, flux linkage equation, torque equation, and motion equation.

[0010] A variable frequency air conditioner model is established based on the permanent magnet synchronous motor model.

[0011] In one possible implementation, the method further includes:

[0012] The first formula describes the analytical expression of the variable frequency air conditioner load: Z = AV 2 ;

[0013] In the formula, Z is the equivalent impedance value, V is the vertical axis, and the constant A = 90η / πT L R, a constant A, is derived by combining the relationship between the rotational speed and mechanical power of the variable frequency air conditioner's mechanical system and the relationship between the voltage and electromagnetic power of the electrical system. In the formula for calculating A, η is the efficiency, and T... L R is the compressor load torque, and R is the grid-side resistance.

[0014] In one possible implementation, the method further includes:

[0015] Based on the aforementioned dynamic characteristics, the constant power load of the variable frequency air conditioner is equivalent to a constant torque load through a rotor speed control strategy.

[0016] In one possible implementation, the method further includes:

[0017] The autonomous control strategy is set to activate when the voltage drops below a preset percentage of the rated voltage.

[0018] Set the delay recovery time so that the capacitor lags behind the voltage recovery time;

[0019] By setting the rotor speed, the variable frequency air conditioner load is changed from a constant power characteristic to a constant impedance characteristic. The rotor speed setting value is as follows:

[0020]

[0021] In one possible implementation, the method further includes:

[0022] Based on the operating characteristics of variable frequency air conditioning loads, the impact of active and reactive load characteristics under voltage control on grid voltage is determined.

[0023] Based on the impact of the active and reactive load characteristics under voltage control on the grid voltage, an equivalent model of variable frequency air conditioning load is established.

[0024] Based on the aforementioned variable frequency air conditioner load equivalent model, the variable frequency air conditioner is autonomously controlled under various voltage conditions.

[0025] Secondly, embodiments of the present invention provide a voltage active support control device for a variable frequency air conditioner, comprising:

[0026] Create a module for building a variable frequency air conditioner model;

[0027] The simulation module is used to simulate the dynamic characteristics of the variable frequency air conditioner under various voltage conditions based on the variable frequency air conditioner model.

[0028] The control module is used to convert the constant power load of the variable frequency air conditioner into a constant torque load based on the dynamic characteristics, and is used for active voltage support control.

[0029] In one possible implementation, the establishment module is further configured to describe the permanent magnet synchronous motor model using voltage equations, flux linkage equations, torque equations, and motion equations; and to establish a variable frequency air conditioner model based on the permanent magnet synchronous motor model.

[0030] In one possible implementation, the simulation module is further configured to describe the analytical expression of the variable frequency air conditioning load using a first formula, wherein the first formula is: Z = AV 2 In the formula, Z is the equivalent impedance value, V is the vertical axis, and the constant A = 90η / πT L R, a constant A, is derived by combining the relationship between the rotational speed and mechanical power of the variable frequency air conditioner's mechanical system and the relationship between the voltage and electromagnetic power of the electrical system. In the formula for calculating A, η is the efficiency, and T... L R is the compressor load torque, and R is the grid-side resistance.

[0031] In one possible implementation, the control module is further configured to convert the constant power load of the variable frequency air conditioner into a constant torque load based on the dynamic characteristics using a rotor speed control strategy.

[0032] In one possible implementation, the control module is further configured to set the autonomous control strategy activation condition to a voltage drop below a preset percentage of the rated voltage; set a delay recovery time to make the capacitor lag behind the voltage recovery time; and change the variable frequency air conditioner load from a constant power characteristic to a constant impedance characteristic by setting the rotor speed, wherein the rotor speed setting value is as follows:

[0033]

[0034] In one possible implementation, the control module is further configured to determine the impact of active and reactive load characteristics under voltage control on the grid voltage based on the variable frequency air conditioner load operating characteristics; establish an equivalent model of the variable frequency air conditioner load based on the impact of the active and reactive load characteristics under voltage control on the grid voltage; and autonomously control the variable frequency air conditioner under various voltage conditions based on the equivalent model of the variable frequency air conditioner load.

[0035] Thirdly, embodiments of the present invention provide an electronic device, including: a processor and a memory, wherein the processor is configured to execute a voltage active support control program for a variable frequency air conditioner stored in the memory, so as to implement the voltage active support control method for a variable frequency air conditioner described in the first aspect above.

[0036] Fourthly, embodiments of the present invention provide a storage medium, comprising: the storage medium storing one or more programs, the one or more programs being executable by one or more processors to implement the voltage active support control method for variable frequency air conditioners described in the first aspect above.

[0037] The voltage active support control scheme for variable frequency air conditioners provided in this invention establishes a variable frequency air conditioner model; simulates the dynamic characteristics of the variable frequency air conditioner under various voltage conditions based on the model; and converts the constant power load of the variable frequency air conditioner into a constant torque load based on the dynamic characteristics for active voltage support control. Compared with existing control schemes for the impact of grid voltage stability, which mostly target fixed frequency air conditioners and have limited research on variable frequency air conditioners, this scheme models the variable frequency air conditioner and simulates its dynamic voltage characteristics under different voltage faults. Furthermore, it converts the constant power load of the variable frequency air conditioner into a constant torque load for different voltage conditions such as voltage dips, voltage interruptions, and voltage recovery, thereby achieving active voltage support control. This fully leverages the role of intelligent load-side control and mitigates the impact on the power grid by improving the load characteristics of the variable frequency air conditioner. Attached Figure Description

[0038] Figure 1 This is a schematic flowchart of a voltage active support control method for a variable frequency air conditioner according to an embodiment of the present invention;

[0039] Figure 2 Figure a shows a simulation model of a variable frequency air conditioner according to an embodiment of the present invention;

[0040] Figure 3 Figure b shows a simulation model of a variable frequency air conditioner according to an embodiment of the present invention;

[0041] Figure 4 This is an ideal voltage-speed control diagram according to an embodiment of the present invention;

[0042] Figure 5 This is a reference rotational speed delay recovery time diagram according to an embodiment of the present invention;

[0043] Figure 6 This is a bus voltage curve of an embodiment of the present invention, showing a voltage drop to 70% of the rated value for 25 consecutive cycles.

[0044] Figure 7 This is a bus current curve diagram of a voltage drop to 70% of the rated value for 25 cycles, according to an embodiment of the present invention.

[0045] Figure 8 This is an active power curve of a voltage drop to 70% of the rated value for 25 cycles, according to an embodiment of the present invention.

[0046] Figure 9This is a reactive power curve of a voltage drop to 70% of the rated value for 25 cycles, according to an embodiment of the present invention.

[0047] Figure 10 This is a schematic diagram of the structure of a voltage active support control device for a variable frequency air conditioner according to an embodiment of the present invention;

[0048] Figure 11 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0051] Figure 1 This is a flowchart illustrating an active voltage support control method for a variable frequency air conditioner according to an embodiment of the present invention. Figure 1 As shown, the method specifically includes:

[0052] S11. Establish a variable frequency air conditioner model.

[0053] In this embodiment of the invention, the variable frequency air conditioner model adopts a permanent magnet synchronous motor model, which includes a three-phase permanent magnet synchronous motor (PMSM), a rectifier-inverter module coordinate transformation module, an SVPWM module position and speed detection module, and a PI adjustment module for the current loop and speed loop.

[0054] The permanent magnet synchronous motor model is described by voltage equations, flux linkage equations, torque equations, and motion equations.

[0055] The three-phase voltage equations for a permanent magnet synchronous motor are as follows:

[0056]

[0057] In the formula, U A U B U C i represents the instantaneous value of the three-phase stator voltage. A i B i C ψ is the instantaneous value of the three-phase stator current. A ψB ψ C R is the instantaneous value of the three-phase stator flux linkage; A R B R C This represents the instantaneous value of the three-phase stator resistance.

[0058] This is transformed into the stator voltage equation based on the dq coordinate system, expressed as:

[0059]

[0060] In the formula, U d U q R represents the voltage values ​​of phases d and q; s ψ is the instantaneous value of the rotor resistance; d ψ q These are the instantaneous values ​​of the flux linkage along the d and q axes.

[0061] The flux linkage equation based on the dq coordinate system is as follows:

[0062]

[0063] In the formula, L d L q ψ represents the inductance components of phases d and q; f The excitation flux linkage is shown to be the d-axis component of the stator flux linkage, which is determined by the magnetic field of the permanent magnet.

[0064] The torque equation based on the dq coordinate system is as follows:

[0065]

[0066] The equations of motion based on the dq coordinate system are as follows:

[0067]

[0068] In the formula, T e For electromagnetic torque, T l Let J be the load torque, J be the moment of inertia, and B be the coefficient of rotational friction.

[0069] The mathematical model of the variable frequency air conditioner is as follows Figure 2 and Figure 3 As shown, module A is the power supply module, module B is the rectifier-inverter module coordinate transformation module, module C is the SVPWM module position and speed detection module, module D is the PI control module for the current loop and speed loop, and module E is the autonomous control strategy module. The PI control coefficients should be selected based on the actual parameters of the air conditioner. This patent provides reference values ​​for the control coefficients: for the speed loop, K... P =7,K I =20; For the d-axis current regulator, KP =13.5, K I =125; for the q-axis current regulator, K P =0.3, K I =125.

[0070] S12. Simulate the dynamic characteristics of the variable frequency air conditioner under various voltage conditions based on the variable frequency air conditioner model.

[0071] The air conditioning load is a constant power load, and the impedance of a constant power load is proportional to the square of the voltage. Therefore, the analytical expression for the air conditioning load can be obtained as Z = AV. 2 In the formula, Z is the equivalent impedance value, V is the vertical axis, and the constant A = 90η / πT L R. The constant A is derived by combining the relationship between the rotational speed and mechanical power of the air conditioning mechanical system and the relationship between the voltage and electromagnetic power of the electrical system. In the formula for calculating A, η is the efficiency, and T... L R represents the compressor load torque, and R represents the grid resistance. Load impedance has a crucial impact on grid voltage; the load can even determine the specific direction of grid voltage to a certain extent. In a voltage collapse event, when the grid voltage drops, the air conditioner's current demand increases. Since the air conditioner is a constant power load, its load impedance decreases, further lowering the grid voltage.

[0072] S13. Based on the dynamic characteristics, the constant power load of the variable frequency air conditioner is equivalent to a constant torque load for active voltage support control.

[0073] By employing a reasonable rotor speed control strategy, a constant-power air conditioner is transformed into a constant-impedance load. The aim is to improve the load characteristics of the variable frequency air conditioner and mitigate its impact on the power grid. The rotor speed control strategy involves setting the autonomous control strategy's activation condition to a voltage drop below 90% of the rated voltage. Simultaneously, considering voltage recovery, the recovery process of the reference speed is delayed, and a buffer time is added to allow the motor speed to increase slowly, resulting in a near-linear speed recovery. A delay in the recovery time is also set to allow sufficient charging time for the capacitor, lagging behind the voltage recovery duration. By setting the rotor speed, the air conditioner load is transformed from a constant-power characteristic to a constant-impedance characteristic. The speed setpoints are as follows:

[0074]

[0075] Since small voltage fluctuations are normal during normal operation of the power system, the proposed control strategy will not activate when the voltage fluctuation range is within ±10%. When the rated voltage is 220V and the rated speed is 1500r / min, the rotor speed control strategy can be derived as follows: Figure 4 .

[0076] By employing a reasonable rotor speed control strategy, the constant power air conditioner is transformed into a constant impedance load, aiming to improve the load characteristics of the variable frequency air conditioner and mitigate the impact on the power grid. Considering the delayed recovery process of the reference speed, a buffer time is added to allow the motor speed to increase slowly, making the speed recovery approximately linear. A delayed recovery time is set to allow the capacitor sufficient charging time, lagging behind the voltage recovery time. Figure 5 For reference, the rotational speed delay recovery time diagram is shown.

[0077] The above-mentioned active voltage support control of variable frequency air conditioners will be applied to the variable frequency air conditioner simulation system.

[0078] The variable frequency air conditioner compressor drive motor is a 220V, 50Hz, 2kW permanent magnet synchronous motor. The load model parameter settings are shown in Table 1.

[0079] Table 1

[0080]

[0081] The bus voltage curve showing a voltage drop to 70% of the rated value for 25 consecutive cycles is shown below. Figure 6 The bus current curve for a voltage drop to 70% of the rated value for 25 consecutive cycles is shown in the figure. Figure 7 .

[0082] During voltage disturbances, the instantaneous current of a traditional fixed-frequency air conditioner increases to 1.5 times the rated current. During voltage drops, it temporarily stabilizes at 1.8 times the rated current. When the voltage recovers, the instantaneous current increases to 2.4 times the rated current. This excessive current can easily cause damage to power grid equipment.

[0083] Compared to fixed-frequency air conditioners, those using traditional variable-frequency and autonomous control strategies experience a drop in current to near zero during voltage dips. This is because of the large capacitance between the inverter and rectifier circuits. The reduced speed of the autonomous control strategy results in lower energy consumption compared to ordinary variable-frequency air conditioners. Therefore, variable-frequency air conditioners with autonomous control strategies have longer diode turn-off times and lower operating current compared to traditional variable-frequency air conditioners. At the moment of fault clearing, the current of fixed-frequency, traditional, and improved variable-frequency air conditioners all surge. The current of the improved variable-frequency air conditioner is slightly lower than the other two, aiming to avoid excessive current. Variable-frequency air conditioners with low-voltage control strategies employ a slow motor speed recovery method to avoid the large current surge during voltage drops.

[0084] Figure 8The graph shows the active power consumption curves for a voltage drop to 70% of the rated value over 25 cycles. It can be seen from the graph that both traditional inverter air conditioners and fixed-frequency air conditioners using the active voltage support control method have significantly lower active power consumption than fixed-frequency air conditioners. This advantage is even more pronounced with the proposed active voltage support control method. This is because the active voltage support control method reduces the engine speed, resulting in lower active power demand. At the moment of a voltage fault, similar to the current change trend, the active power of the inverter air conditioner drops to zero due to the effect of the uncontrolled rectifier. Subsequently, as the large capacitor discharges, the active power gradually recovers. After the voltage fault is resolved, the instantaneous impact of active power on the inverter air conditioner using the proposed active voltage support control method is far lower than that of the fixed-frequency air conditioner due to the delayed recovery of the engine speed.

[0085] Because of the large capacitor between the rectifier bridge and the inverter, when the grid voltage drops to 70% of its rated value at t=0.4s, the capacitor begins to discharge, and the DC bus voltage gradually decreases. At this time, under the autonomous control strategy, the inverter air conditioner automatically reduces the motor speed when the voltage drops. Because the reduction in the motor's active power consumption slows down the capacitor discharge process, it provides more time for the grid voltage to recover. This method can effectively delay motor stalling, thereby reducing the incidence of motor stall.

[0086] Figure 9 The graph shows the reactive power curve when the voltage drops to 70% of the rated value for 25 consecutive cycles. As shown, when a voltage fault occurs, the reactive power of the inverter air conditioner first drops to zero, then remains at a constant level close to zero. When the voltage fault is restored, due to capacitor charging, the reactive power of the inverter air conditioner initially shows a low reactive power flow. However, for the fixed-frequency air conditioner, a high reactive power demand is maintained during both the voltage fault occurrence and disconnection. This sudden increase in reactive power demand contradicts the lack of reactive power in the power grid. To meet the reactive power demand of the temperature-controlled load, the power grid will further reduce the voltage or disconnect the load, thus causing the voltage to continue to drop, creating a vicious cycle that ultimately leads to a voltage collapse accident. Figure 9 It can be seen that, in general, the variable frequency air conditioner under the autonomous control strategy has the lowest reactive power among the three types of air conditioning loads.

[0087] The voltage active support control scheme for variable frequency air conditioners provided in this invention establishes a variable frequency air conditioner model; simulates the dynamic characteristics of the variable frequency air conditioner under various voltage conditions based on the model; and converts the constant power load of the variable frequency air conditioner into a constant torque load based on the dynamic characteristics for active voltage support control. Compared with existing control schemes for the impact of grid voltage stability, which mostly target fixed frequency air conditioners and have limited research on variable frequency air conditioners, this scheme models the variable frequency air conditioner and simulates its dynamic voltage characteristics under different voltage faults. Furthermore, it converts the constant power load of the variable frequency air conditioner into a constant torque load for different voltage conditions such as voltage dips, voltage interruptions, and voltage recovery, thereby achieving active voltage support control. This fully leverages the role of intelligent load-side control and mitigates the impact on the power grid by improving the load characteristics of the variable frequency air conditioner.

[0088] Figure 10 A schematic diagram of the structure of a voltage active support control device for a variable frequency air conditioner according to an embodiment of the present invention is shown, as follows: Figure 10 As shown, the device includes:

[0089] Module 1001 is used to build a variable frequency air conditioner model. For detailed explanations, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0090] The simulation module 1002 is used to simulate the dynamic characteristics of the variable frequency air conditioner under various voltage conditions based on the variable frequency air conditioner model. For detailed explanations, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0091] The control module 1003 is used to convert the constant power load of the variable frequency air conditioner into a constant torque load based on the dynamic characteristics, and is used for active voltage support control. For detailed explanation, please refer to the relevant descriptions in the above method embodiments; they will not be repeated here.

[0092] The voltage active support control device for variable frequency air conditioners provided in this embodiment of the invention is used to execute the voltage active support control method for variable frequency air conditioners provided in the above embodiment. Its implementation method and principle are the same. For details, please refer to the relevant description of the above method embodiment, which will not be repeated here.

[0093] Figure 11 An electronic device according to an embodiment of the present invention is shown, such as... Figure 11 As shown, the electronic device may include a processor 1101 and a memory 1102, wherein the processor 1101 and the memory 1102 may be connected via a bus or other means. Figure 11 Taking the example of a connection between China and Israel via a bus.

[0094] Processor 1101 may be a central processing unit (CPU). Processor 1101 may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof.

[0095] The memory 1102, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the methods provided in the embodiments of the present invention. The processor 1101 executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions, and modules stored in the memory 1102, thereby implementing the methods in the above-described method embodiments.

[0096] The memory 1102 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 1101, etc. Furthermore, the memory 1102 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 1102 may optionally include memory remotely located relative to the processor 1101, and these remote memories may be connected to the processor 1101 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0097] One or more modules are stored in memory 1102 and, when executed by processor 1101, perform the methods described in the above method embodiments.

[0098] The specific details of the aforementioned electronic device can be understood by referring to the relevant descriptions and effects in the above method embodiments, and will not be repeated here.

[0099] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0100] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A voltage active support control method for a variable frequency air conditioner, characterized in that, include: Establish a variable frequency air conditioner model; The dynamic characteristics of a variable frequency air conditioner under various voltage conditions are simulated based on the aforementioned variable frequency air conditioner model. Based on the aforementioned dynamic characteristics, the constant power load of the variable frequency air conditioner is equivalent to a constant torque load for active voltage support control. Specifically, when the voltage fluctuation range is outside ±10%, the establishment of the variable frequency air conditioner model includes: The permanent magnet synchronous motor model is described by voltage equation, flux linkage equation, torque equation, and motion equation. A variable frequency air conditioner model was established based on the permanent magnet synchronous motor model. The simulation of the dynamic characteristics of a variable frequency air conditioner under various voltage conditions based on the variable frequency air conditioner model includes: The first formula describes the analytical expression for the load of a variable frequency air conditioner: ; In the formula, This is the equivalent impedance value. The vertical axis is a constant. ,constant The relationship between the rotational speed and mechanical power of the variable frequency air conditioner's mechanical system and the relationship between the voltage and electromagnetic power of the electrical system were derived simultaneously. In the calculation formula, For efficiency, This is the compressor load torque. This is the grid-side resistance.

2. The method according to claim 1, characterized in that, The method of equipping the constant power load of the variable frequency air conditioner with a constant torque load based on the dynamic characteristics for active voltage support control includes: Based on the aforementioned dynamic characteristics, the constant power load of the variable frequency air conditioner is equivalent to a constant torque load through a rotor speed control strategy.

3. The method according to claim 1, characterized in that, The method further includes: Based on the operating characteristics of variable frequency air conditioning loads, the impact of active and reactive load characteristics under voltage control on grid voltage is determined. Based on the impact of the active and reactive load characteristics under voltage control on the grid voltage, an equivalent model of variable frequency air conditioning load is established. Based on the aforementioned variable frequency air conditioner load equivalent model, the variable frequency air conditioner is autonomously controlled under various voltage conditions.

4. A voltage active support control device for a variable frequency air conditioner, characterized in that, include: Create a module for building a variable frequency air conditioner model; The simulation module is used to simulate the dynamic characteristics of the variable frequency air conditioner under various voltage conditions based on the variable frequency air conditioner model. The control module is used to convert the constant power load of the variable frequency air conditioner into a constant torque load based on the dynamic characteristics, and is used for active voltage support control. When the voltage fluctuation range is outside ±10%, the establishment module is also used to describe the permanent magnet synchronous motor model through voltage equation, flux linkage equation, torque equation and motion equation; and to establish a variable frequency air conditioner model based on the permanent magnet synchronous motor model. The simulation module is also used to describe the analytical expression of the variable frequency air conditioner load using a first formula, which is: ; In the formula, This is the equivalent impedance value. The vertical axis is a constant. ,constant The relationship between the rotational speed and mechanical power of the variable frequency air conditioner's mechanical system and the relationship between the voltage and electromagnetic power of the electrical system were derived simultaneously. In the calculation formula, For efficiency, This is the compressor load torque. This is the grid-side resistance.

5. An electronic device, characterized in that, include: A processor and a memory, the processor being configured to execute a voltage active support control program for an inverter air conditioner stored in the memory, to implement the voltage active support control method for an inverter air conditioner as described in any one of claims 1 to 3.

6. A storage medium, characterized in that, The storage medium stores one or more programs, which can be executed by one or more processors to implement the voltage active support control method for the variable frequency air conditioner according to any one of claims 1 to 3.

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