Fan control system and air conditioner

Abstract

The invention discloses a fan control system and an air conditioner. The target air speed of a fan is calculated according to the target air volume of the fan; the PI parameter is corrected through the compensation coefficient eta, and PI control is conducted on the draught fan according to the difference value between the target wind speed and the actual wind speed of the draught fan; calculating a corresponding verification rotating speed according to the actual wind speed of the fan; and whether the difference value between the calculated verification rotating speed and the actual rotating speed of the fan is within a set difference value range or not is judged, if yes, the compensation coefficient eta is kept unchanged, and if not, the compensation coefficient eta is updated through the actual wind speed and the actual rotating speed of the fan. Therefore, by means of the fan control system, the technical problem that in the prior art, the fan cannot be controlled according to the air volume requirement is solved. And moreover, the compensation coefficient eta is updated by utilizing the actual wind speed and the actual rotating speed of the fan, and the PI parameter is corrected by utilizing the compensation coefficient eta, so that the control accuracy of the fan is ensured.

Description

Technical Field

[0001] The present invention relates to the field of control technologies, and particularly to a fan control system and an air conditioner. Background Art

[0002] Air conditioner fans generally use fixed-frequency fans with single-phase AC motors and variable-frequency fans with three-phase AC permanent magnet synchronous motors (PMSMs). For the fixed-frequency fans with single-phase AC motors, although they have the advantages of simple structure and reliability, they cannot perform stepless speed regulation, and the fan efficiency is relatively low. The permanent magnet synchronous motor has a high power density, a small volume, and a simple structure. When vector control (FOC) is used for speed regulation, it has the advantages of fast dynamic response, high efficiency, low noise, safety and reliability. Therefore, most air conditioner manufacturers in the industry currently use permanent magnet synchronous fans as condenser fans.

[0003] In the FOC speed regulation of permanent magnet synchronous motors, the methods for obtaining the motor speed and rotor position are relatively complex. Currently, the mainstream speed measurement methods are mainly divided into two types. The first is to measure the speed by adding mechanical speed measurement devices such as encoders; the second is the sensorless speed detection method, including back electromotive force detection (Luenberger Observer) and rotor position / speed reconstruction algorithms. The speed measurement scheme using current sensors plus position and speed sensors has a high cost and a complex structure, so the sensorless speed detection scheme is usually used. The FOC control uses the difference between the given speed and the actual speed, generates the reference value of the quadrature-axis current through the speed proportional-integral PI regulator, and generates the voltage in the stationary coordinate system through the current PI regulator and the Park transformation module according to the difference between the reference values and the actual values of the direct-axis and quadrature-axis stator currents. The generated voltage then conducts the three-phase inverter through the pulse modulation of SVPWM, so as to achieve the control effect on the permanent magnet synchronous motor.

[0004] All current fan speed regulation control methods take the motor speed as the control target. For example, speed control algorithms such as FOC and DTC can already achieve accurate, stable, and efficient control of the motor speed. However, in quite a number of air conditioner usage scenarios, there is a high demand for accurate control of the air volume. There is no fan control scheme based on the regulation of wind speed and air volume in the industry, so that the motor speed and the air output volume cannot be accurately matched. If the fan speed and wind speed are manually matched during the system debugging process in the development stage, it will increase the development and debugging time and cost.

[0005] Therefore, the current control method of the air conditioner fan is the closed-loop control of the motor speed. This control method lacks the observation and direct control of the fan wind speed and cannot be accurately adjusted according to the air volume demand of the actual scenario. Summary of the Invention

[0006] The present invention provides a fan control system, which solves the technical problem in the prior art that the fan cannot be controlled according to the air volume requirement.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a fan control system, including:

[0009] A target wind speed calculation module, configured to calculate the target wind speed of the fan according to the target air volume of the fan;

[0010] A control module, configured to correct the PI parameters by using a compensation coefficient η; perform PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan;

[0011] A judgment module, configured to calculate the corresponding verification speed according to the actual wind speed of the fan; judge whether the difference between the calculated verification speed and the actual speed of the fan is within a set difference range. If so, the compensation coefficient η remains unchanged. If not, the compensation coefficient η is updated by using the actual wind speed and the actual speed of the fan.

[0012] In some embodiments of the present application, the calculating the corresponding verification speed according to the actual wind speed of the fan specifically includes:

[0013] Obtain the actual wind speed v of the fan c ;

[0014] Calculate the verification speed n j =v c *A / (η*k);

[0015] Wherein,

[0016] A is the area of the fan air outlet; k is a constant.

[0017] In some embodiments of the present application, the updating the compensation coefficient η by using the actual wind speed and the actual speed of the fan specifically includes:

[0018] Update the compensation coefficient η by using the following formula;

[0019] Compensation coefficient η = v c *A / (n c *k);

[0020] Wherein, v c is the actual wind speed of the fan; n c is the actual speed of the fan;

[0021] A is the area of the fan air outlet; k is a constant.

[0022] In some embodiments of the present application, before updating the compensation coefficient η using the actual wind speed and actual rotation speed of the fan, the following steps are further included:

[0023] Judge whether the actual wind speed or actual rotation speed of the fan is 0;

[0024] If so, issue an alarm prompt;

[0025] If not, update the compensation coefficient η using the actual wind speed and actual rotation speed of the fan.

[0026] In some embodiments of the present application, the PI parameters are corrected using the compensation coefficient η; specifically, it includes:

[0027] Kp′ = Kp * A / (η * k);

[0028] Ki′ = Ki * A / (η * k);

[0029] Wherein,

[0030] Kp′ and Ki′ are the corrected proportional parameter and integral parameter respectively;

[0031] Kp and Ki are the preset proportional parameter and integral parameter respectively;

[0032] A is the area of the fan air outlet; k is a constant.

[0033] In some embodiments of the present application, calculating the target wind speed of the fan according to the target air volume of the fan specifically includes:

[0034] Obtain the target air volume and air outlet area of the fan;

[0035] Calculate the ratio of the target air volume to the air outlet area to obtain the target wind speed of the fan.

[0036] In some embodiments of the present application, the judgment module specifically includes:

[0037] A calibration rotation speed calculation unit, which is used to calculate the corresponding calibration rotation speed according to the actual wind speed of the fan;

[0038] A calibration rotation speed judgment unit, which is used to judge whether the difference between the calculated calibration rotation speed and the actual rotation speed of the fan is within the set difference range;

[0039] A compensation coefficient update unit, which is used to update the compensation coefficient η using the actual wind speed and actual rotation speed of the fan when the difference between the calculated calibration rotation speed and the actual rotation speed of the fan is not within the set difference range.

[0040] In some embodiments of the present application, the target air volume is an external input signal received by the target wind speed calculation module;

[0041] The actual wind speed of the fan is measured by a wind speed sensor.

[0042] In some embodiments of the present application, the control module specifically includes:

[0043] A correction unit for correcting the PI parameters of the wind speed outer loop PI controller by using a compensation coefficient η;

[0044] A Clark transformation unit for converting the three-phase current of the motor into the α-axis current Iα and β-axis current Iβ in a two-phase stationary coordinate system;

[0045] A Park transformation unit for converting the α-axis current Iα and β-axis current Iβ in the two-phase stationary coordinate system into the q-axis current Iq and d-axis current Id in a rotating coordinate system;

[0046] A wind speed outer loop PI controller for performing PI control based on the difference between the target wind speed and the actual wind speed of the fan, and outputting a q-axis current set value Iqr;

[0047] A first current inner loop PI controller for performing PI control based on the difference between the q-axis current set value Iqr and the q-axis current Iq, and outputting a q-axis voltage Uq;

[0048] A second current inner loop PI controller for performing PI control based on the difference between the d-axis current set value Idr and the d-axis current Id, and outputting a d-axis voltage Ud;

[0049] A Park inverse transformation unit for performing a Park inverse transformation on the q-axis voltage U q and d-axis voltage U d to obtain the α-axis voltage Uα and β-axis voltage Uβ in the two-phase stationary coordinate system;

[0050] A space vector pulse width modulation unit for generating a control signal based on the α-axis voltage Uα and β-axis voltage Uβ and outputting it to a three-phase inverter;

[0051] A three-phase inverter for generating a three-phase voltage signal according to the control signal and outputting it to the fan.

[0052] The present invention provides an air conditioner including the fan control system described above.

[0053] The present invention provides a storage medium storing executable instructions of the fan control system.

[0054] The technical solution of the present invention has the following technical effects compared with the prior art: For the fan control system and air conditioner of the present invention, the target wind speed of the fan is calculated according to the target air volume of the fan; the PI parameters are corrected by using the compensation coefficient η, and the fan is PI-controlled according to the difference between the target wind speed and the actual wind speed of the fan; the corresponding calibration speed is calculated according to the actual wind speed of the fan; it is judged whether the difference between the calculated calibration speed and the actual speed of the fan is within the set difference range. If so, the compensation coefficient η remains unchanged. If not, the compensation coefficient η is updated by using the actual wind speed and the actual speed of the fan. Therefore, the fan control system of this embodiment obtains the target wind speed according to the target air volume, and performs PI control on the fan wind speed so that the actual wind speed of the fan reaches the target wind speed, realizing accurate adjustment of the fan according to the target air volume, and solving the technical problem in the prior art that the fan cannot be controlled according to the air volume demand. Moreover, the compensation coefficient η is updated by using the actual wind speed and the actual speed of the fan, and the PI parameters are corrected by using the compensation coefficient η to ensure the accuracy of the fan control.

[0055] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become clearer. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only 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.

[0057] Figure 1 It is a structural block diagram of an embodiment of the fan control system of the present invention;

[0058] Figure 2 It is a flowchart of an embodiment of the steps executed by the fan control system of the present invention;

[0059] Figure 3 It is a flowchart of an embodiment of the steps executed by the control module;

[0060] Figure 4 It is a flowchart of an embodiment of the steps executed by the judgment module;

[0061] Figure 5 It is a flowchart of an embodiment of the steps executed by the target wind speed calculation module;

[0062] Figure 6 It is a flowchart of another embodiment of the steps executed by the judgment module;

[0063] Figure 7Flowchart of another embodiment of the steps executed by the judgment module;

[0064] Figure 8 Structural block diagram of an embodiment of the judgment module;

[0065] Figure 9 Structural block diagram of an embodiment of the control module;

[0066] Figure 10 Structural block diagram of another embodiment of the fan control system of the present invention;

[0067] Figure 11 Structural block diagram of another embodiment of the fan control system of the present invention;

[0068] Figure 12 Flowchart of another embodiment of the steps executed by the fan control system of the present invention. Detailed implementation manners

[0069] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0070] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0071] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0072] In the description of the present application, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0073] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0074] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0075] The air conditioner performs the refrigeration cycle and the heating cycle of the air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator, and is controlled by a controller to achieve the control of the refrigerant flow direction and the opening degree control of the expansion valve, etc. The refrigeration cycle and the heating cycle include a series of processes, involving compression, condensation, expansion, and evaporation, and supplying the refrigerant to the air that has been conditioned and heat-exchanged.

[0076] The compressor compresses the refrigerant gas in a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0077] The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in the low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant for heat exchange with the material to be cooled. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0078] The outdoor unit of the air conditioner refers to the part of the refrigeration cycle including the compressor and the outdoor heat exchanger. The indoor unit of the air conditioner includes the indoor heat exchanger, and the expansion valve can be provided in the outdoor unit or the indoor unit of the air conditioner.

[0079] The indoor heat exchanger and the outdoor heat exchanger are used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner serves as a heater in the heating mode. When the indoor heat exchanger is used as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0080] The air conditioner of this embodiment includes a fan control system for controlling the fan.

[0081] The fan control system of this embodiment includes a target wind speed calculation module, a control module, a judgment module, etc., as shown in Figure 1 shown.

[0082] The target wind speed calculation module is configured to calculate the target wind speed of the fan according to the target air volume of the fan.

[0083] The control module is configured to correct the PI parameters by using the compensation coefficient η; perform PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan.

[0084] The judgment module is configured to calculate the corresponding calibration speed according to the actual wind speed of the fan; judge whether the difference between the calculated calibration speed and the actual speed of the fan is within the set difference range. If so, the compensation coefficient η remains unchanged. If not, the compensation coefficient η is updated by using the actual wind speed and the actual speed of the fan.

[0085] Therefore, the fan control system specifically executes the following steps, as shown in Figure 2 shown.

[0086] Step S11: The target wind speed calculation module calculates the target wind speed of the fan according to the target air volume of the fan and sends it to the control module.

[0087] Step S12: The control module corrects the PI parameters by using the compensation coefficient η and performs PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan.

[0088] Step S13: The judgment module calculates the corresponding verification speed based on the actual wind speed of the fan; it determines whether the difference between the calculated verification speed and the actual speed of the fan is within the set difference range.

[0089] If so, it means that the difference between the verification speed and the actual speed is small, and the compensation coefficient η remains unchanged; if not, it means that the difference between the verification speed and the actual speed is large, and the compensation coefficient η is corrected and updated using the actual wind speed of the fan and the actual speed of the fan. Then return to step S11.

[0090] When the set difference range is 0, determining whether the difference between the verification speed and the actual speed is within the set difference range is to determine whether the verification speed is equal to the actual speed.

[0091] The control module specifically executes the following steps, see Figure 3 as shown.

[0092] Step S21: Correct the PI parameters using the compensation coefficient η.

[0093] The control module obtains the current compensation coefficient η and corrects the PI parameters using the compensation coefficient η.

[0094] When the fan is powered on and running for the first time, the compensation coefficient η is the preset initial value.

[0095] Step S22: Perform PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan.

[0096] When the control module performs PI control in each control cycle, it first obtains the current compensation coefficient η, corrects the PI parameters using the current compensation coefficient η to obtain accurate PI parameters, and then performs PI control according to the difference between the target wind speed and the actual wind speed of the fan to generate a control amount for controlling the operation of the fan so that the actual wind speed of the fan reaches the target wind speed.

[0097] By designing steps S21 - S22, accurate PI parameters can be obtained to achieve precise control of the fan.

[0098] The judgment module specifically executes the following steps, see Figure 4 as shown.

[0099] Step S31: Calculate the corresponding verification speed according to the actual wind speed of the fan.

[0100] Step S32: Determine whether the difference between the calculated verification speed and the actual speed of the fan is within the set difference range.

[0101] If it is within the set difference range, then execute step S33: The compensation coefficient η remains unchanged.

[0102] If it is not within the set difference range, step S34 is executed: The compensation coefficient η is corrected and updated using the actual wind speed of the fan and the actual rotation speed of the fan.

[0103] By designing steps S31 to S34, it is determined whether to correct and update the compensation coefficient η based on whether the difference between the calibrated rotation speed and the actual rotation speed of the fan is within the set difference range, and a relatively accurate compensation coefficient η can be obtained.

[0104] The compensation coefficient η is updated using the actual wind speed of the fan and the actual rotation speed of the fan, and the PI parameters are corrected in real time using the compensation coefficient η to ensure the accuracy of the fan control.

[0105] After the compensation coefficient η is updated, the PI parameters are corrected in real time to ensure the accuracy of the PI control.

[0106] The fan control system of this embodiment calculates the target wind speed of the fan according to the target air volume of the fan; corrects the PI parameters using the compensation coefficient η, and performs PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan; calculates the corresponding calibrated rotation speed according to the actual wind speed of the fan; determines whether the difference between the calculated calibrated rotation speed and the actual rotation speed of the fan is within the set difference range. If so, the compensation coefficient η remains unchanged. If not, the compensation coefficient η is updated using the actual wind speed of the fan and the actual rotation speed of the fan. Therefore, the fan control system of this embodiment obtains the target wind speed according to the target air volume, performs PI control on the fan wind speed so that the actual wind speed of the fan reaches the target wind speed, realizes accurate adjustment of the fan according to the target air volume, and solves the technical problem in the prior art that the fan cannot be controlled according to the air volume requirement. Moreover, the compensation coefficient η is updated using the actual wind speed of the fan and the actual rotation speed of the fan, and the PI parameters are corrected using the compensation coefficient η to ensure the accuracy of the fan control.

[0107] The fan control system of this embodiment is a closed-loop control of the fan wind speed, observes and directly controls the fan wind speed, and realizes accurate adjustment of the fan according to the air volume requirement of the actual scenario.

[0108] In some embodiments of the present application, the target air volume is an external input signal received by the target wind speed calculation module. The target wind speed calculation module calculates the target wind speed according to the received target air volume.

[0109] Measuring the actual wind speed of the fan using a wind speed sensor is simple, convenient, and accurate. The wind speed sensor transmits the measured actual wind speed of the fan to the control module and the judgment module respectively.

[0110] In some embodiments of the present application, calculating the target wind speed of the fan according to the target air volume of the fan specifically includes the following steps, see Figure 5 as shown.

[0111] Step S11-1: Obtain the target air volume Q of the fan and the outlet area A of the fan.

[0112] Step S11-2: Calculate the ratio of the target air volume Q to the outlet area A to obtain the target wind speed of the fan. Target wind speed = Q / A.

[0113] By designing steps S11-1 to S11-2, using the target air volume Q of the fan and the outlet area A of the fan, the target wind speed of the fan can be calculated simply and accurately.

[0114] In some embodiments of the present application, the corresponding calibration speed is calculated according to the actual wind speed of the fan, which specifically includes the following steps. See Figure 6 as shown.

[0115] Step S41: Obtain the actual wind speed v of the fan c .

[0116] Measure the actual wind speed of the fan using a wind speed sensor.

[0117] Step S42: Calculate the calibration speed n j = v c * A / (n * k).

[0118] where n j is the calibration speed; v c is the actual wind speed of the fan.

[0119] A is the area of the fan outlet; η is the compensation coefficient.

[0120] k is a preset constant, which is the proportionality coefficient between the fan air volume and the fan speed.

[0121] The fan air volume is proportional to the fan speed, and k is the proportionality coefficient between the fan air volume and the fan speed.

[0122] By designing steps S41 to S42, using the actual wind speed v of the fan c , the area A of the fan outlet, the compensation coefficient η, and the proportionality coefficient k, the relatively accurate calibration speed n can be calculated simply and conveniently j .

[0123] In some embodiments of the present application, the compensation coefficient η is updated using the actual wind speed and the actual speed of the fan, which specifically includes:

[0124] The compensation coefficient η is updated using the following formula;

[0125] Compensation coefficient η = v c * A / (n c * k);

[0126] Among them, v c is the actual wind speed of the fan; n c is the actual rotational speed of the fan;

[0127] A is the area of the air outlet of the fan; k is a preset constant, which is the proportionality coefficient between the air volume of the fan and the rotational speed of the fan.

[0128] Using the actual wind speed v of the fan c , the actual rotational speed n of the fan c , the area A of the air outlet of the fan, and the proportionality coefficient k, a relatively accurate compensation coefficient η can be calculated.

[0129] In some embodiments of the present application, before updating the compensation coefficient η using the actual wind speed and the actual rotational speed of the fan, the following steps are further included, as shown in Figure 7 shown.

[0130] Step 34-1: Determine whether the actual wind speed or the actual rotational speed of the fan is 0.

[0131] If so, execute step S34-2: Send an alarm prompt.

[0132] If not, execute step S34: Update the compensation coefficient η using the actual wind speed and the actual rotational speed of the fan.

[0133] Before updating the compensation coefficient η using the actual wind speed and the actual rotational speed of the fan, if the actual wind speed or the actual rotational speed of the fan is 0, it is possible that the fan has a fault. At this time, an alarm prompt is sent to remind the user for timely maintenance.

[0134] The PI parameters include a proportional parameter and an integral parameter. In some embodiments of the present application, the PI parameters are corrected using the compensation coefficient η; specifically including:

[0135] Kp′ = Kp * A / (η * k);

[0136] Ki′ = Ki * A / (η * k);

[0137] Among them,

[0138] Kp′ and Ki′ are the corrected proportional parameter and integral parameter respectively;

[0139] Kp and Ki are the preset proportional parameter and integral parameter respectively;

[0140] A is the area of the air outlet of the fan; k is a preset constant, which is the proportionality coefficient between the air volume of the fan and the rotational speed of the fan.

[0141] By designing the above two correction formulas, using the area A of the fan outlet, the compensation coefficient n, and the proportional coefficient k, the preset proportional parameter Kp and integral parameter Ki are corrected to obtain relatively accurate corrected proportional parameter Kp' and integral parameter Ki', so as to achieve accurate PI control.

[0142] In some embodiments of the present application, the judgment module specifically includes a verification speed calculation unit, a verification speed judgment unit, a compensation coefficient update unit, etc., as shown in Figure 8 shown.

[0143] The verification speed calculation unit is used to calculate the corresponding verification speed according to the actual wind speed of the fan.

[0144] The verification speed judgment unit is used to judge whether the difference between the calculated verification speed and the actual speed of the fan is within the set difference range.

[0145] The compensation coefficient update unit is used to update the compensation coefficient η using the actual wind speed and the actual speed of the fan when the difference between the calculated verification speed and the actual speed of the fan is not within the set difference range.

[0146] After the verification speed calculation unit calculates the verification speed, it sends it to the verification speed judgment unit. The verification speed judgment unit judges whether the difference between the calculated verification speed and the actual speed of the fan is within the set difference range, and when it is determined that it is not within the set difference range, it sends an update signal to the compensation coefficient update unit. The compensation coefficient update unit updates the compensation coefficient η using the actual wind speed and the actual speed of the fan.

[0147] By designing the judgment module to include a verification speed calculation unit, a verification speed judgment unit, and a compensation coefficient update unit, it is convenient to design and implement the functions of each unit. Each unit works together and performs its own duties to jointly update the compensation coefficient.

[0148] In some embodiments of the present application, the control module specifically includes a correction unit, a Clark transformation unit, a Park transformation unit, a wind speed outer loop PI controller, a first current inner loop PI controller, a second current inner loop PI controller, a Park inverse transformation unit, a space vector pulse width modulation unit, a three-phase inverter, etc., as shown in Figure 9 shown.

[0149] The correction unit is used to correct the PI parameters of the wind speed outer loop PI controller using the compensation coefficient η.

[0150] The Clark transformation unit is used to convert the three-phase currents Iu, Iv, and Iw of the motor into the α-axis current Iα and β-axis current Iβ in the two-phase stationary coordinate system.

[0151] A Park transformation unit, which is used to convert the α-axis current Iα and β-axis current Iβ in the two-phase stationary coordinate system into the q-axis current Iq and d-axis current Id in the rotating coordinate system.

[0152] An outer-loop PI controller for wind speed, which is used to perform PI control based on the difference between the target wind speed and the actual wind speed of the wind turbine, and output the q-axis current set value Iqr.

[0153] A first inner-loop PI controller for current, which is used to perform PI control based on the difference between the q-axis current set value Iqr and the q-axis current Iq, and output the q-axis voltage Uq.

[0154] A second inner-loop PI controller for current, which is used to perform PI control based on the difference between the d-axis current set value Idr and the d-axis current Id, and output the d-axis voltage Ud.

[0155] A Park inverse transformation unit, which is used to perform Park inverse transformation on the q-axis voltage U q and d-axis voltage U d to obtain the α-axis voltage Uα and β-axis voltage Uβ in the two-phase stationary coordinate system.

[0156] A space vector pulse width modulation unit, which is used to generate a control signal according to the α-axis voltage Uα and β-axis voltage Uβ through the space vector pulse width modulation algorithm, and output it to the three-phase inverter.

[0157] The space vector pulse width modulation unit, namely the SVPWM unit, can obtain the control signal of the three-phase inverter through the space vector pulse width modulation algorithm.

[0158] A three-phase inverter, which is used to generate three-phase voltage signals according to the control signal and output them to the wind turbine.

[0159] The PI parameters of the outer-loop PI controller for wind speed are corrected using the compensation coefficient η.

[0160] The PI parameters of the first inner-loop PI controller for current and the second inner-loop PI controller for current are preset values.

[0161] See Figure 10 As shown, the three-phase currents Iu, Iv, and Iw of the motor are subjected to Clark transformation to be converted into the α-axis current Iα and β-axis current Iβ in the two-phase stationary coordinate system. The α-axis current Iα and β-axis current Iβ in the two-phase stationary coordinate system are subjected to Park transformation to be converted into the q-axis current Iq and d-axis current Id in the rotating coordinate system.

[0162] Perform PI control on the difference between the target wind speed and the actual wind speed of the wind turbine, and output the q-axis current set value Iqr. Perform PI control on the difference between the q-axis current set value Iqr and the q-axis current Iq, and output the q-axis voltage Uq. Perform PI control on the difference between the d-axis current set value Idr and the d-axis current Id, and output the d-axis voltage Ud. Perform park inverse transformation on the q-axis voltage U q and the d-axis voltage U d to obtain the α-axis voltage Uα and the β-axis voltage Uβ in the two-phase stationary coordinate system. Perform space vector pulse width modulation based on the α-axis voltage Uα and the β-axis voltage Uβ to generate a control signal, which is output to the three-phase inverter to control the three-phase inverter to output a three-phase voltage signal, and the three-phase voltage signal is used to drive the wind turbine to operate.

[0163] By designing the control module to include a correction unit, a Clark transformation unit, a Park transformation unit, a wind speed outer-loop PI controller, a first current inner-loop PI controller, a second current inner-loop PI controller, a Park inverse transformation unit, a space vector pulse width modulation unit, and a three-phase inverter, it is convenient to design and implement the functions of each unit. Each unit works together and performs its own duties to jointly achieve the closed-loop control of the wind turbine.

[0164] The control module also includes a position sensor and a speed sensor, which are respectively used to detect the rotor angle and the actual speed of the wind turbine.

[0165] Next, the control principle of the wind turbine control system will be specifically described.

[0166] The selection of the control quantity and the feedback quantity of the control system is an important parameter in the design of the control system. Replace the speed control quantity in the traditional wind turbine control system with the wind speed, and the structure diagram of the new control system is as shown in Figure 11 shown.

[0167] Figure 11 In it, the target wind speed calculation module and the verified speed calculation unit are integrated together, which is called the wind field model. The verified speed judgment unit and the compensation coefficient update unit are integrated together, which is called the speed verification module.

[0168] Integrate the wind speed outer-loop PI controller, the first current inner-loop PI controller, and the second current inner-loop PI controller together, which is called the controller.

[0169] Integrate the Clark transformation unit, the Park transformation unit, the Park inverse transformation unit, the space vector pulse width modulation unit, the three-phase inverter, the position sensor, and the speed sensor together, which is called the wind turbine driver.

[0170] The system inputs the target air volume according to the actual demand. After passing through the wind field model (specifically referring to the target wind speed calculation module), the target air volume is converted into the target wind speed and input into the controller. The controller calculates the control output value based on the difference between the target wind speed and the measured wind speed output by the wind speed sensor, and sends it to the driver to control the operation and speed regulation of the fan. During the operation of the system, the fan driver periodically detects the fan speed, and at the same time converts the measured wind speed into the verified speed through the wind field model (specifically referring to the verified speed calculation unit) for speed verification, so as to perform real-time correction on the parameters (compensation coefficient η) of the wind field model and ensure the accuracy of control.

[0171] Assume that the system resistance is constant, that is, the change in system resistance at different wind speeds is ignored. According to the fan law, the air volume is proportional to the speed, that is, Q∝n, where Q is the air volume and n is the fan speed. The air volume Q = k * n, and k is the proportionality coefficient between the fan air volume and the fan speed.

[0172] Let the outlet area be A, then the wind speed v = Q / A = k * n / A, where k is the proportionality coefficient.

[0173] From the above formula, it can be concluded that the outlet wind speed v of the fan is proportional to the fan speed n, and the proportionality coefficient between the wind speed and the speed is k / A, which depends on the design parameters of the fan, such as the impeller diameter, blade angle, etc.

[0174] For common axial fans, the theoretical air volume Q can be approximated as Q = vπD 2 / 4, where D is the impeller diameter. Then the relationship between the wind speed v and the speed n is: v = 4kn / (πD 2 )

[0175] In actual operation, the following factors need to be considered:

[0176] (1) System resistance: The resistance of the air duct or condenser fins will change the operating point and affect the linear relationship between the wind speed and the speed;

[0177] (2) Efficiency loss: Mechanical friction, air turbulence, etc. cause the actual wind speed to be lower than the theoretical value;

[0178] (3) Air density: The air density decreases in a high-temperature environment, and the wind speed decreases slightly at the same speed.

[0179] Therefore, the influence caused by the above factors can be reduced to a unified comprehensive efficiency coefficient (i.e., compensation coefficient) to correct the model, which is represented by η.

[0180] The corrected wind speed calculation formula is: v = n * k * n / A. The comprehensive efficiency coefficient η in the formula can be corrected in real time through speed verification during the operation of the system to improve the accuracy of the model.

[0181] According to the above formula, the calculation formula for the rotational speed can be obtained as: n = v * A / (n * k).

[0182] The wind field model mainly includes two formulas:

[0183] v = Q / A; used to calculate the target wind speed based on the target air volume;

[0184] n = v * A / (n * k); used to calculate and verify the rotational speed based on the actual wind speed of the fan.

[0185] Since the parameters of the wind field model are affected by factors such as the environment, system parameters, and operating conditions, the comprehensive efficiency coefficient (i.e., the compensation coefficient η) changes in real time, resulting in a non-linear relationship between the wind speed and the fan rotational speed, thus affecting the stability and accuracy of the control system. Due to the complexity of the actual system parameters and environmental parameters, as well as the large differences in parameters among different models, it is relatively difficult to obtain the change law of the comprehensive efficiency coefficient through experimental and analytical calculation methods. It requires a large amount of manpower, time, and cost, and it is not easy to obtain ideal results. Therefore, in order to reduce the cost of model correction and improve the development efficiency, this solution designs rotational speed verification to perform online model parameter correction, and obtains a wind field model with higher accuracy through a dual redundant verification mechanism.

[0186] The rotational speed verification uses sensors and algorithms to substitute the rotational speed measured in real time in each cycle and the wind speed measured in real time into the wind field model, calculate and obtain the latest parameters (i.e., the compensation coefficient η), and update the parameters of the previous cycle.

[0187] The specific steps are as follows:

[0188] Step 1: Estimate the initial coefficients η0 and k according to the system parameters and the fan model. η0 is the preset initial value of the compensation coefficient η.

[0189] Step 2: Collect the wind speed v1 in the first cycle;

[0190] Step 3: Detect the fan rotational speed n1 in the first cycle;

[0191] Step 4: Use the wind field model to calculate the verification rotational speed in the first cycle

[0192] Step 5: Calculate the actual comprehensive efficiency coefficient η1 in the first cycle as:

[0193]

[0194] Step 6: Repeat Steps 2 to 5 to calculate the actual comprehensive efficiency coefficient ηi in the i-th cycle.

[0195] The traditional FOC control algorithm based on speed feedback consists of a speed outer loop, a current inner loop, coordinate transformation, space vector pulse width modulation, a three-phase inverter, a permanent magnet synchronous motor, and a position sensor.

[0196] Modify the speed outer loop in the FOC control algorithm to a wind speed outer loop, add a wind speed sensor to measure the real-time wind speed, and calculate the output of the outer loop through a PI controller. The output quantity is used as the input value of the current inner loop to participate in the control. The new system block diagram is as Figure 10 shown.

[0197] In the original control algorithm, the speed outer loop is actually the integral of the current inner loop. After replacing the outer loop control quantity with the wind speed, due to the uncertainty of the comprehensive efficiency coefficient, the linear PI controller is no longer applicable, and the parameters of the PI controller need to be corrected in real time. Commonly used non-linear PI controllers include fuzzy PI controllers and adaptive PI controllers. In this scheme, since the time-varying parameters in the wind field model can be corrected by the speed verification link, for the convenience of design and to reduce the complexity of the controller, the method of correcting the PI parameters according to the comprehensive efficiency coefficient is used to optimize the controller.

[0198] Expression of the original speed loop PI controller:

[0199] u o = Kp·Δn + Ki·∑Δn

[0200] where Δn is the difference between the desired speed and the measured speed.

[0201] After replacing the speed with the wind speed, the expression of the latest wind speed outer loop PI controller can be obtained:

[0202]

[0203] Through the above formula, the corrected PI parameters can be obtained as:

[0204]

[0205] where η is iteratively updated according to the speed verification result in each cycle, so as to realize the periodic iterative update of the PI parameters.

[0206] For the control flow of the fan control system, see Figure 12 shown.

[0207] Step S51: Input the target air volume.

[0208] Step S52: Wind field model calculation: Calculate the target wind speed according to the target air volume.

[0209] Step S53: Read the measured value of the wind speed sensor.

[0210] Step S54: The controller calculates the difference between the target wind speed and the measured wind speed and generates a control output.

[0211] Step S55: The driver adjusts the fan speed.

[0212] Step S56: Wind field model calculation: Calculate the calibration speed based on the measured wind speed.

[0213] Step S57: Determine whether the calibration speed is equal to the measured speed.

[0214] If they are equal, the parameter η remains unchanged.

[0215] If they are not equal, execute Step S58: Correct the wind field model parameter η.

[0216] In the fan control system of this embodiment, wind speed feedback is used to replace motor speed feedback to directly control the air outlet speed of the fan, enabling the air conditioning system to adjust the fan according to the real-time air volume demand and accurately obtain the actual air volume that conforms to the expected air volume.

[0217] This embodiment improves the method for determining the wind field model parameter (compensation coefficient η). By calculating the correction amount of the wind field model parameter based on the real-time obtained wind speed and motor speed, the wind field model parameter is corrected in real time to ensure the accuracy and adaptability of the wind field model.

[0218] Using wind speed feedback to replace motor speed feedback to directly control the wind speed of the fan enables the system to perform precise control according to the performance requirements of the air-cooled system, improving the accuracy of fan control; during the system debugging process, the debugging process of matching the fan speed with the required air volume is omitted, improving the development efficiency and reducing the development economic cost and time cost. Through the method of speed calibration and real-time model correction, the adaptability of the wind field model in different application scenarios is improved, the accuracy and adaptability of the controller parameters are improved, and the control precision is improved.

[0219] The fan control system of this embodiment realizes precise control of the fan for air volume following demand through wind speed feedback adjustment, has high adaptability to different models and scenarios, has relatively high model accuracy, reduces the difficulty of controlling parameter debugging, and improves the control precision.

[0220] Based on the design of the above fan control system, this embodiment also proposes an air conditioner including the described fan control system.

[0221] The air conditioner of this embodiment designs a fan control system to obtain the target wind speed according to the target air volume, and performs PI control on the fan wind speed so that the actual wind speed of the fan reaches the target wind speed, achieving accurate adjustment of the fan according to the target air volume and solving the technical problem in the prior art that the fan cannot be controlled according to the air volume requirement. Moreover, the compensation coefficient η is updated by using the actual wind speed and the actual rotation speed of the fan, and the PI parameters are corrected by using the compensation coefficient η to ensure the accuracy of the fan control and improve the market competitiveness of the air conditioner.

[0222] Based on the design of the above fan control system, this embodiment also proposes a storage medium that stores the executable instructions of the fan control system.

[0223] The storage medium stores the executable instructions of the target wind speed calculation module, the control module, and the judgment module.

[0224] The executable instructions are used to make the fan control system execute the following steps to achieve accurate control of the fan.

[0225] Steps to be executed:

[0226] Calculate the target wind speed of the fan according to the target air volume of the fan;

[0227] Correct the PI parameters by using the compensation coefficient η, and perform PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan;

[0228] Calculate the corresponding verification rotation speed according to the actual wind speed of the fan; judge whether the difference between the calculated verification rotation speed and the actual rotation speed of the fan is within the set difference range. If so, the compensation coefficient η remains unchanged. If not, update the compensation coefficient η by using the actual wind speed and the actual rotation speed of the fan.

[0229] The above computer storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The computer storage medium can be any available storage medium accessible by a general-purpose or special-purpose computer.

[0230] In some embodiments, a computer storage medium is coupled to a processor such that the processor can read information from, and write information to, the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an Application Specific Integrated Circuits (ASIC). Of course, the processor and the storage medium can also exist as discrete components in a device.

[0231] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

[0232] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A fan control system, characterized in that: include: The target wind speed calculation module is configured to: calculate the target wind speed of the fan according to the target wind volume of the fan; The control module is configured to: modify the PI parameter using the compensation coefficient η; and perform PI control on the fan according to the difference between the target wind speed and the actual wind speed of the fan; The judgment module is configured as follows: calculate the corresponding verification speed according to the actual wind speed of the fan; judge whether the difference between the calculated verification speed and the actual speed of the fan is within the set difference range, if so, the compensation coefficient η remains unchanged, if not, the compensation coefficient η is updated using the actual wind speed of the fan and the actual speed of the fan.

2. The fan control system according to claim 1, characterized in that: The step of calculating the corresponding verification speed according to the actual wind speed of the fan specifically includes: Get the actual wind speed v of the fan c ; Calculate the calibration speed n j =v c *A / (η*k); in, A is the area of ​​the fan outlet; k is a constant.

3. The fan control system according to claim 1, characterized in that: The updating of the compensation coefficient η by using the actual wind speed and the actual rotation speed of the fan specifically includes: The compensation coefficient η is updated using the following formula: Compensation coefficient η=v c *A / (n c *k); Among them, v c is the actual wind speed of the fan; n c is the actual speed of the fan; A is the area of ​​the fan outlet; k is a constant.

4. The fan control system according to claim 1, characterized in that: Before the actual wind speed and the actual rotation speed of the fan are used to update the compensation coefficient η, the following steps are also included: Determine whether the actual wind speed or actual speed of the fan is 0; If so, an alarm is issued; If not, the compensation coefficient η is updated using the actual wind speed and the actual rotation speed of the fan.

5. The fan control system according to claim 1, characterized in that: The method of using the compensation coefficient η to correct the PI parameter specifically includes: Kp′=Kp*A / (η*k); Ki′=Ki*A / (η*k); in, Kp′ and Ki′ are respectively the corrected proportional parameter and integral parameter; Kp and Ki are the preset proportional parameter and integral parameter respectively; A is the area of ​​the fan outlet; k is a constant.

6. The fan control system according to claim 1, characterized in that: The step of calculating the target wind speed of the fan according to the target wind volume of the fan specifically includes: Obtain the target air volume and outlet area of ​​the fan; The ratio of the target air volume to the air outlet area is calculated to obtain the target wind speed of the fan.

7. The fan control system according to claim 1, characterized in that: The judgment module specifically includes: A verification speed calculation unit, which is used to calculate the corresponding verification speed according to the actual wind speed of the fan; A verification speed determination unit, which is used to determine whether the difference between the calculated verification speed and the actual speed of the fan is within a set difference range; The compensation coefficient updating unit is used to update the compensation coefficient η using the actual wind speed and the actual rotation speed of the fan when the difference between the calculated verification rotation speed and the actual rotation speed of the fan is not within the set difference range.

8. The fan control system according to claim 1, characterized in that: The target wind volume is an external input signal received by the target wind speed calculation module; the actual wind speed of the fan is measured using a wind speed sensor.

9. The fan control system according to any one of claims 1 to 8, characterized in that: The control module specifically includes: A correction unit, which is used to correct the PI parameters of the wind speed outer loop PI controller using the compensation coefficient η; A Clark transformation unit is used to transform the three-phase current of the motor into an α-axis current Iα and a β-axis current Iβ in a two-phase stationary coordinate system; A Park conversion unit, which is used to convert the α-axis current Iα and the β-axis current Iβ in the two-phase stationary coordinate system into the q-axis current Iq and the d-axis current Id in the rotating coordinate system; The wind speed outer loop PI controller is used to perform PI control according to the difference between the target wind speed of the wind turbine and the actual wind speed of the wind turbine, and output a q-axis current set value Iqr; A first current inner loop PI controller, which is used to perform PI control according to the difference between the q-axis current setting value Iqr and the q-axis current Iq, and output a q-axis voltage Uq; A second current inner loop PI controller, which is used to perform PI control according to the difference between the d-axis current setting value Idr and the d-axis current Id, and output a d-axis voltage Ud; Park inverse conversion unit, which is used to convert the q-axis voltage U q , d-axis voltage U d Perform inverse park transformation to obtain the α-axis voltage Uα and the β-axis voltage Uβ in the two-phase stationary coordinate system; A space vector pulse width modulation unit, which is used to generate a control signal according to the α-axis voltage Uα and the β-axis voltage Uβ, and output the control signal to the three-phase inverter; The three-phase inverter is used to generate a three-phase voltage signal according to the control signal and output it to the wind turbine.

10. An air conditioner, characterized in that The invention comprises a wind turbine control system as claimed in any one of claims 1 to 9.

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