Variable switching frequency control method, device and equipment of EC fan and storage medium
Patent Information
- Application Number
- CN202610906200.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-23
- Publication Date
- 2026-09-25
AI Technical Summary
若开关频率固定，则无法根据不同转速工况下EC风机的噪音特性对开关频率进行适应性优化，使开关损耗无法得到有效限制，影响EC风机整体运行效率
[0016]本申请先通过在不同转速工况下对EC风机的开关频率进行适应性调整，使开关频率与转速之间形成与工况适配的映射关系，并通过标定曲线记录该映射关系，为变开关频率策略提供确切的开关频率调整依据，以提高开关频率的控制效率；接着通过一阶惯性滤波法或斜坡限制法对标定曲线提供的开关频率对应值进行平滑处理，避免开关频率突变引起的电流冲击和转矩脉动，确保EC风机的电机平稳运行；随后通过第一定时器和第二定时器构成双定时器解耦架构，利用固定的第二中断频率保证FOC电流环运算和滑模观测器算法能够始终以最优频率执行，保持带宽一致性并提高控制精度；最后通过滑模观测器算法对电流采样延时进行自适应补偿，使EC风机的开关频率动态调节时，提高滑模观测器对EC风机的电机转子位置的估算精度，在第一定时器和第二定时器的配合下，完成对EC风机的电机的无位置传感器协同控制，实现稳定的开关频率切换。
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Figure CN122824040A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of motor control technology, and in particular to a variable switching frequency control method, device, equipment and storage medium for EC fans. Background Technology
[0002] EC (Electronically Commutated) fans use DC brushless motors to achieve electronic commutation. They can be directly powered by AC power and internally convert AC power to DC power to drive the motor. Compared with traditional AC fans, they are more energy efficient and quieter, and are therefore widely used in fields with high requirements for energy saving and control precision.
[0003] Existing EC (Electronic Controlled Fan) fans primarily employ a PWM modulation strategy with a fixed switching frequency for control. At low speeds, the aerodynamic noise of the EC fan is relatively low, with electromagnetic noise at the switching frequency and its harmonics becoming the dominant noise source. At high speeds, the aerodynamic noise of the EC fan is significant, and the electromagnetic noise is masked by the aerodynamic noise. If the switching frequency is fixed, it is impossible to adaptively optimize the switching frequency according to the noise characteristics of the EC fan under different speed conditions, thus failing to effectively limit switching losses and affecting the overall operating efficiency of the EC fan.
[0004] Existing variable switching frequency schemes for EC wind turbines often involve step-like abrupt changes during frequency switching, leading to PWM duty cycle update timing disorders and transient impacts in the current loop, causing motor torque pulsation and speed fluctuations. Furthermore, changes in switching frequency directly affect the current sampling timing and delay, causing phase lag in the input current signal of sensorless algorithms such as sliding mode observers, increasing angle estimation errors, and in severe cases, causing motor step loss. Summary of the Invention
[0005] In view of this, the purpose of this application is to reduce the noise and switching losses of the EC fan and improve the accuracy of motor rotor position estimation by adaptively adjusting the switching frequency under different operating speeds through a variable switching frequency strategy. The specific technical solution is as follows.
[0006] In a first aspect, this application provides a variable switching frequency control method for an EC wind turbine, comprising the following steps: S1. Dividing the speed range of the EC wind turbine into multiple speed segments, setting corresponding switching frequencies based on the noise characteristics of the EC wind turbine in each speed segment, and obtaining a calibration curve of the switching frequency with respect to the speed; S2. Obtaining the actual speed of the EC wind turbine, obtaining the switching frequency corresponding to the actual speed through the calibration curve, and smoothing the switching frequency corresponding to the actual speed to obtain a target switching frequency; S3. According to the target switching frequency, updating the switching frequency of the EC wind turbine through a first timer, and executing FOC current loop operation and sliding mode observer algorithm through a second timer to compensate for current sampling delay.
[0007] Optionally, step S1 includes: S101. Dividing the speed range of the EC fan into a low-speed section, a medium-speed section, and a high-speed section; S102. Setting corresponding switching frequencies based on the noise characteristics of the EC fan in the low-speed section, the medium-speed section, and the high-speed section, and obtaining a calibration curve in which the switching frequency decreases in a gradient as the speed increases.
[0008] Optionally, the low-speed section, the medium-speed section, and the high-speed section are respectively 20%-30% of the rated speed, 30%-75% of the rated speed, and 75%-100% of the rated speed of the EC fan; in the calibration curve, the switching frequency corresponding to the low-speed section is 10kHz, the switching frequency corresponding to the medium-speed section decreases linearly or piecewise from 10kHz to 4kHz, and the switching frequency corresponding to the high-speed section is 4kHz.
[0009] Optionally, step S2 includes: S201. Obtaining the actual rotational speed of the EC fan, and obtaining the switching frequency corresponding to the actual rotational speed through the calibration curve; S202. Smoothing the switching frequency corresponding to the actual rotational speed through a first-order inertial filtering method or a ramp limiting method to obtain the target switching frequency.
[0010] Optionally, in the first-order inertial filtering method, the target switching frequency is obtained through the following recursive formula: In the formula, Represents the time variable. The target switching frequency at the current moment, This represents the target switching frequency at the previous moment. This indicates the switching frequency corresponding to the actual rotational speed at the current moment. This represents the smoothing coefficient.
[0011] Optionally, step S3 includes: S301. Based on the target switching frequency, a PWM wave is generated at a first interrupt frequency using a first timer to drive a three-phase full-bridge inverter, thereby driving the motor of the EC wind turbine to update the switching frequency of the EC wind turbine to the target switching frequency; S302. Based on the target switching frequency, an FOC current loop operation and sliding mode observer algorithm are executed at a second interrupt frequency using a second timer, and the current sampling delay is compensated in a manner where the compensation amount is negatively correlated with the switching frequency.
[0012] Optionally, the first interrupt frequency is a variable frequency, the second interrupt frequency is a fixed frequency, and the second interrupt frequency is independent of the first interrupt frequency.
[0013] Secondly, this application provides a variable switching frequency control device for an EC wind turbine, which executes the aforementioned variable switching frequency control method for an EC wind turbine, including: a calibration unit that divides the speed range of the EC wind turbine into multiple speed segments, sets corresponding switching frequencies based on the noise characteristics of the EC wind turbine in each speed segment, and obtains a calibration curve of the switching frequency with respect to the speed; an acquisition unit that acquires the actual speed of the EC wind turbine, obtains the switching frequency corresponding to the actual speed through the calibration curve, and smooths the switching frequency corresponding to the actual speed to obtain a target switching frequency; and an update compensation unit that updates the switching frequency of the EC wind turbine according to the target switching frequency through a first timer, and executes FOC current loop operation and sliding mode observer algorithm through a second timer to compensate for the current sampling delay.
[0014] Thirdly, this application provides an electronic device, which includes a processor and a memory; wherein the memory is used to store a computer program, which is loaded and executed by the processor to implement the aforementioned variable switching frequency control method for EC wind turbines.
[0015] Fourthly, this application provides a computer-readable storage medium for storing a computer program, which, when executed by a processor, implements the aforementioned variable switching frequency control method for EC wind turbines.
[0016] This application first adaptively adjusts the switching frequency of the EC fan under different operating speeds, establishing a mapping relationship between the switching frequency and speed that is adapted to the operating conditions. This mapping relationship is recorded using a calibration curve, providing a precise basis for adjusting the switching frequency for the variable switching frequency strategy, thereby improving the control efficiency of the switching frequency. Next, the corresponding switching frequency values provided by the calibration curve are smoothed using a first-order inertial filtering method or a ramp limiting method to avoid current surges and torque pulsations caused by sudden changes in switching frequency, ensuring the smooth operation of the EC fan motor. Subsequently, a dual-timer decoupling architecture is constructed using a first timer and a second timer. A fixed second interrupt frequency ensures that the FOC current loop operation and the sliding mode observer algorithm can always execute at the optimal frequency, maintaining bandwidth consistency and improving control accuracy. Finally, the sliding mode observer algorithm adaptively compensates for the current sampling delay, improving the estimation accuracy of the EC fan motor rotor position by the sliding mode observer when the switching frequency of the EC fan is dynamically adjusted. With the cooperation of the first and second timers, sensorless collaborative control of the EC fan motor is achieved, realizing stable switching frequency switching. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0018] Figure 1 A flowchart of the variable switching frequency control method for EC wind turbines provided in this application embodiment.
[0019] Figure 2 A flowchart of the calibration method provided in the embodiments of this application.
[0020] Figure 3 This is a schematic diagram of the calibration curve in the calibration method provided in the embodiments of this application.
[0021] Figure 4 A flowchart of the acquisition method provided in the embodiments of this application.
[0022] Figure 5 A flowchart of the update compensation method provided in the embodiments of this application.
[0023] Figure 6 The timing diagram shows the dual-timer decoupling architecture in the update compensation method provided in the embodiments of this application.
[0024] Figure 7 This is a schematic diagram of the variable switching frequency control device for the EC fan provided in an embodiment of this application.
[0025] Figure 8 This is a structural diagram of an electronic device provided in an embodiment of this application. Detailed Implementation
[0026] 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, and 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.
[0027] See Figure 1 This application provides a variable switching frequency control method for an EC wind turbine, comprising the following steps.
[0028] S1. Divide the speed range of the EC fan into multiple speed segments, and set the corresponding switching frequency based on the noise characteristics of the EC fan in each speed segment to obtain the calibration curve of the switching frequency with respect to the speed.
[0029] S2. Obtain the actual speed of the EC fan, obtain the switching frequency corresponding to the actual speed through the calibration curve, smooth the switching frequency corresponding to the actual speed, and obtain the target switching frequency.
[0030] S3. Based on the target switching frequency, update the switching frequency of the EC wind turbine through the first timer, and execute the FOC current loop operation and sliding mode observer algorithm through the second timer to compensate for the current sampling delay.
[0031] Through the above implementation method, this embodiment uses a variable switching frequency strategy to adaptively adjust the switching frequency under different speed conditions, thereby reducing the noise and switching losses of the EC fan and improving the accuracy of motor rotor position estimation.
[0032] See Figure 2 This embodiment provides a calibration method, which, as a further implementation of step S1 above, includes the following steps.
[0033] S101. Divide the speed range of the EC fan into low-speed, medium-speed and high-speed sections.
[0034] S102. Based on the noise characteristics of the EC fan in the low-speed, medium-speed and high-speed sections, the corresponding switching frequencies are set to obtain a calibration curve in which the switching frequency decreases in a gradient with the increase of the rotational speed.
[0035] In this embodiment, the noise characteristics of the EC fan include aerodynamic noise, electromagnetic switch noise, and total noise spectrum. Aerodynamic noise is generated by the rotation of the EC fan blades and is positively correlated with the rotational speed; electromagnetic switch noise is generated by the inverter's PWM switching action and is related to the switching frequency and its harmonics; the total noise spectrum can be collected using a sound level meter or microphone array.
[0036] Regarding the speed range division of EC fans, it is understandable that in the low-speed range, aerodynamic noise is relatively low, and electromagnetic switch noise becomes the dominant noise source; in the medium-speed range, aerodynamic noise increases, and the proportion of electromagnetic switch noise decreases relatively; in the high-speed range, aerodynamic noise is relatively high, and electromagnetic switch noise is masked by aerodynamic noise.
[0037] In practical applications, the calibration curve can be stored in the form of a lookup table or a piecewise linear function to represent the mapping relationship between the switching frequency and the rotational speed.
[0038] Based on the above calibration method, this embodiment adaptively adjusts the switching frequency under the three key operating conditions of EC fans in the low-speed, medium-speed, and high-speed sections, so that a mapping relationship between the switching frequency and the rotational speed is formed that is adapted to the operating conditions. The mapping relationship is recorded by calibration curves, providing a precise basis for the switching frequency adjustment for variable switching frequency strategies, thereby improving the control efficiency of the switching frequency.
[0039] In a further embodiment of the above calibration method, the low-speed section, medium-speed section, and high-speed section are 20%-30% of the rated speed, 30%-75% of the rated speed, and 75%-100% of the rated speed of the EC fan, respectively; in the calibration curve, the switching frequency corresponding to the low-speed section is 10kHz, the switching frequency corresponding to the medium-speed section decreases linearly or piecewise from 10kHz to 4kHz, and the switching frequency corresponding to the high-speed section is 4kHz.
[0040] Based on the above implementation method, this embodiment sets the switching frequency to a relatively high 10kHz in the low-speed range, so that the fundamental frequency of electromagnetic switch noise and its main harmonic frequencies (20kHz, 30kHz, etc.) are far away from the sensitive frequency band or higher than the range of human hearing (>20kHz), thus achieving ultrasonic silent operation of the EC fan; in the medium-speed range, the switching frequency is gradually reduced from 10Hz to 4kHz, reducing switching losses while ensuring that the electromagnetic switch noise is not abrupt; in the high-speed range, the switching frequency is reduced to the minimum of 4kHz, minimizing switching losses and improving the energy efficiency of the EC fan. At the same time, since aerodynamic noise is dominant at this time, even if the electromagnetic switch noise is relatively larger than in the low-speed and medium-speed ranges, the user experience is unlikely to be affected by the electromagnetic switch noise.
[0041] See Figure 3In one specific embodiment of the previous example, taking a 5.5kW rated power EC fan as an example, the switching frequency in the medium-speed range decreases from 10kHz to 4kHz in segments. Specifically, the switching frequencies in the 30%-45% rated speed range, 45%-60% rated speed range, and 60%-75% rated speed range of the EC fan are 8kHz, 6kHz, and 5kHz, respectively. The switching frequency shows a step-like decreasing trend, which is beneficial for reducing the switching frequency in the medium-speed range while allowing the EC fan to gradually adapt to each switching frequency, avoiding a sudden increase in electromagnetic switch noise. Compared with the traditional fixed switching frequency scheme, this embodiment can improve the overall energy efficiency of the EC fan by 5%-10% in the low-speed, medium-speed, and high-speed ranges.
[0042] In this embodiment, Figure 3 The diagram also shows the mapping relationship between the output power and the rotational speed of an EC fan with a rated power of 5.5KW. By combining this curve with the calibration curve, it can be seen that under the variable switching frequency strategy in this embodiment, the output power of the EC fan increases smoothly with the increase of the rotational speed, so that the energy efficiency of the EC fan is reasonably controlled.
[0043] See Figure 4 This embodiment provides an acquisition method, which, as a further implementation of step S2 above, includes the following steps.
[0044] S201. Obtain the actual speed of the EC fan and, through the calibration curve, obtain the switching frequency corresponding to the actual speed.
[0045] S202. The switching frequency corresponding to the actual rotational speed is smoothed by using a first-order inertial filtering method or a ramp limiting method to obtain the target switching frequency.
[0046] In one specific implementation of the above acquisition method, for the first-order inertial filtering method, the target switching frequency is obtained by the following recursive formula.
[0047] .
[0048] In the formula, Represents the time variable. The target switching frequency at the current moment, This indicates the target switching frequency at the previous moment. This indicates the switching frequency corresponding to the actual rotational speed at the current moment. This represents the smoothing coefficient. In practical applications, The preferred value is 0.3.
[0049] In another specific implementation of the above acquisition method, for the ramp limiting method, the maximum change in the switching frequency at each step is limited during execution (e.g., a maximum change of 0.01kHz per control cycle). When the target switching frequency and the actual rotational speed correspond to a switching frequency exceeding a preset threshold, the target switching frequency is gradually approached at a fixed slope.
[0050] Based on the above acquisition method, this embodiment uses a first-order inertial filtering method or a ramp limiting method to smooth the corresponding value of the switching frequency provided by the calibration curve, so as to avoid current surges and torque pulsations caused by sudden changes in switching frequency and ensure the smooth operation of the EC fan motor.
[0051] See Figure 5 This embodiment provides an update compensation method, as a further implementation of step S3 above, which includes the following steps.
[0052] S301. Based on the target switching frequency, a PWM wave is generated at the first interrupt frequency through the first timer to drive the three-phase full-bridge inverter, thereby driving the motor of the EC fan to update the switching frequency of the EC fan to the target switching frequency.
[0053] S302. Based on the target switching frequency, the FOC current loop operation and sliding mode observer algorithm are executed at the second interrupt frequency through the second timer, and the current sampling delay is compensated in a way that the compensation amount is negatively correlated with the switching frequency.
[0054] In this embodiment, the first timer is configured as a 6-channel complementary PWM output mode with four-zone insertion (such as the advanced timer mode of TIM1 / TIM8 in the MCU), directly driving the six power switches of the three-phase full-bridge inverter. The first timer is responsible for generating the PWM waveform, and its period register and compare register support real-time dynamic updates. The second timer is used to perform FOC current loop calculations (including Clark / Park transformation, current regulator, inverse Park transformation, SVPWM duty cycle calculation) and sliding mode observer algorithms. The specific process of the FOC current loop calculation can use existing technology, which will not be described in detail here.
[0055] For the first timer, it is understood that once the target switching frequency is determined, its frequency value is updated in the period register at the underflow interrupt or commutation point of the PWM cycle of the first timer to ensure that the duty cycle switching is aligned with the PWM cycle boundary, avoiding abnormal pulse width caused by non-integer cycle switching. Combined with the aforementioned smoothing processing of the switching frequency corresponding to the actual speed, the switching frequency switching process (such as reducing from 10kHz to 4kHz) can be completed within tens to hundreds of control cycles, thus effectively suppressing current surges and torque ripples.
[0056] See Figure 6In one specific implementation of the above-mentioned update compensation method, the first interrupt frequency is a variable frequency, the second interrupt frequency is a fixed frequency, and the second interrupt frequency is independent of the first interrupt frequency.
[0057] For the second timer, it can be understood that the second timer is independently configured as a fixed-frequency periodic interrupt (e.g., the second interrupt frequency is 10kHz, i.e., triggered once at 100μm), which is completely decoupled from the first interrupt frequency of the first timer. No matter how the first interrupt frequency changes (e.g., from 10kHz to 4kHz), the second timer always maintains its fixed second interrupt frequency.
[0058] Based on the above implementation, this embodiment uses a first timer and a second timer to form a dual-timer decoupled architecture. Changes in the switching frequency only affect the PWM wave generation period of the first timer, and do not affect the execution period of the second timer for FOC current loop operation and sliding mode observer algorithm. The fixed second interrupt frequency ensures that the FOC current loop operation and sliding mode observer algorithm can always be executed at the optimal frequency, avoiding performance fluctuations caused by the coupling of switching frequency and control frequency in traditional schemes, maintaining bandwidth consistency and improving control accuracy.
[0059] Regarding the current sampling delay, it is understandable that in single-resistor or dual-resistor sampling schemes, the current sampling time is usually scheduled at the midpoint or underflow point of the PWM cycle. For example, when the switching frequency decreases from 10kHz to 4kHz, the switching cycle correspondingly increases from 100μs to 250μs. If the sampling time is not adjusted synchronously, the delay of the sampled current relative to the actual current increases, resulting in a phase lag in the current signal input to the sliding mode observer, which in turn causes errors in the estimated back EMF and rotor angle.
[0060] In this embodiment, to address the aforementioned issues, the sliding mode observation algorithm employs a current sampling delay compensation strategy based on the switching frequency.
[0061] First, a quantitative analysis of the time delay of the sampled current is performed. At different switching frequencies, the time delay of the current sampling point relative to the start of the PWM cycle varies. Let the switching period be... The current sampling delay is Switching frequency When reduced, the switching cycle Increase; if the current sampling point remains fixed at the switching cycle The midpoint of the current sampling delay As it increases, for example: when hour, , ;when hour, , .
[0062] Subsequently, the current sampling delay is compensated in a manner where the compensation amount is negatively correlated with the switching frequency. Based on the current switching frequency... Real-time calculation of the current switching cycle and current current sampling delay Phase lead compensation is performed at the current input of the sliding mode observer. Specifically, the current signal vector is rotated in the sliding mode observer coordinate system to compensate for the current sampling delay. The introduced current signal is phase-lagging. The lower the current switching frequency... Current switching cycle The larger the value, the longer the current sampling delay. The larger the value, the greater the compensation; conversely, the smaller the value, the smaller the compensation.
[0063] Based on the above implementation, this embodiment uses a sliding mode observer algorithm to adaptively compensate for the current sampling delay, thereby improving the estimation accuracy of the motor rotor position of the EC wind turbine by the sliding mode observer when the switching frequency of the EC wind turbine is dynamically adjusted. With the cooperation of the first timer and the second timer, sensorless collaborative control of the motor of the EC wind turbine is completed, achieving stable switching frequency switching.
[0064] See Figure 7 This application also provides a variable switching frequency control device for EC wind turbines. This device can be implemented as all or part of a terminal through software, hardware, or a combination of both, or it can be integrated as an independent module on a server. Specifically, the device includes a calibration unit 701, an acquisition unit 702, and an update compensation unit 703.
[0065] The calibration unit 701 is used to divide the speed range of the EC fan into multiple speed segments, set the corresponding switching frequency based on the noise characteristics of the EC fan in each speed segment, and obtain the calibration curve of the switching frequency with respect to the speed.
[0066] The acquisition unit 702 is used to acquire the actual speed of the EC fan, obtain the switching frequency corresponding to the actual speed through the calibration curve, and smooth the switching frequency corresponding to the actual speed to obtain the target switching frequency.
[0067] The update compensation unit 703 is used to update the switching frequency of the EC wind turbine according to the target switching frequency through the first timer, and to execute the FOC current loop operation and sliding mode observer algorithm through the second timer to compensate for the current sampling delay.
[0068] It should be noted that the device provided in the above embodiments, when executing the variable switching frequency control method for EC wind turbines, is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the equipment can be divided into different functional modules to complete all or part of the functions described above. Furthermore, the device provided in the above embodiments and the variable switching frequency control method embodiments for EC wind turbines belong to the same concept, and its implementation process is detailed in the method embodiments, which will not be repeated here.
[0069] See Figure 8 This application also discloses an electronic device 80, including: at least one processor 81, at least one memory 82, a power supply 83, a communication interface 84, an input / output interface 85, and a communication bus 86. The memory 82 stores a computer program, which is loaded and executed by the processor 81 to implement the relevant steps in the variable switching frequency control method for EC wind turbines disclosed in any of the foregoing embodiments. Furthermore, the electronic device 80 in this embodiment can specifically be an electronic computer.
[0070] In this embodiment, the power supply 83 is used to provide operating voltage for the various hardware devices on the electronic device 80; the communication interface 84 can create a data transmission channel between the electronic device 80 and external devices, and the communication protocol it follows can be any communication protocol applicable to the technical solution of this application, and is not specifically limited here; the input / output interface 85 is used to acquire external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs, and is not specifically limited here.
[0071] In addition, the memory 82, as a carrier for resource storage, can be a read-only memory, random access memory, disk, or optical disk, etc. The resources stored thereon can include an operating system 821, computer programs 822, etc., and the storage method can be temporary storage or permanent storage.
[0072] The operating system 821 is used to manage and control the various hardware devices on the electronic device 80 and the computer program 822, which may be Windows Server, Netware, Unix, Linux, etc. In addition to including a computer program capable of performing the network request processing method executed by the electronic device 80 as disclosed in any of the foregoing embodiments, the computer program 822 may further include a computer program capable of performing other specific tasks.
[0073] Furthermore, this application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the aforementioned variable switching frequency control method for EC wind turbines. Specific steps of this method can be found in the corresponding content disclosed in the foregoing embodiments, and will not be repeated here.
[0074] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0075] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0076] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.
[0077] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0078] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A variable switching frequency control method for an EC fan, characterized in that, Includes the following steps: S1. Divide the speed range of the EC fan into multiple speed segments, and set the corresponding switching frequency based on the noise characteristics of the EC fan in each speed segment to obtain the calibration curve of the switching frequency with respect to the speed. S2. Obtain the actual rotational speed of the EC fan, and through the calibration curve, obtain the switching frequency corresponding to the actual rotational speed. Smooth the switching frequency corresponding to the actual rotational speed to obtain the target switching frequency. S3. Based on the target switching frequency, update the switching frequency of the EC wind turbine through the first timer, and execute the FOC current loop operation and sliding mode observer algorithm through the second timer to compensate for the current sampling delay.
2. The variable switching frequency control method for EC wind turbines according to claim 1, characterized in that, Step S1 includes: S101. Divide the speed range of the EC fan into low-speed, medium-speed and high-speed sections; S102. Based on the noise characteristics of the EC fan in the low-speed section, the medium-speed section and the high-speed section, set the corresponding switching frequency to obtain a calibration curve in which the switching frequency decreases in a gradient with the increase of the rotational speed.
3. The variable switching frequency control method for EC fans according to claim 2, characterized in that, The low-speed section, the medium-speed section, and the high-speed section are respectively 20%-30% of the rated speed, 30%-75% of the rated speed, and 75%-100% of the rated speed of the EC fan; In the calibration curve, the switching frequency corresponding to the low-speed section is 10kHz, the switching frequency corresponding to the medium-speed section decreases linearly or piecewise from 10kHz to 4kHz, and the switching frequency corresponding to the high-speed section is 4kHz.
4. The variable switching frequency control method for EC wind turbines according to claim 1, characterized in that, Step S2 includes: S201. Obtain the actual rotational speed of the EC fan, and obtain the switching frequency corresponding to the actual rotational speed through the calibration curve; S202. The switching frequency corresponding to the actual rotational speed is smoothed by using a first-order inertial filtering method or a ramp limiting method to obtain the target switching frequency.
5. The variable switching frequency control method for EC wind turbines according to claim 4, characterized in that, In the first-order inertial filtering method, the target switching frequency is obtained through the following recursive formula: ； In the formula, Represents the time variable. The target switching frequency at the current moment, This represents the target switching frequency at the previous moment. This indicates the switching frequency corresponding to the actual rotational speed at the current moment. This represents the smoothing coefficient.
6. The variable switching frequency control method for EC wind turbines according to claim 1, characterized in that, Step S3 includes: S301. Based on the target switching frequency, a PWM wave is generated at a first interrupt frequency using a first timer to drive a three-phase full-bridge inverter, thereby driving the motor of the EC wind turbine to update the switching frequency of the EC wind turbine to the target switching frequency. S302. Based on the target switching frequency, the FOC current loop operation and sliding mode observer algorithm are executed at the second interrupt frequency through the second timer, and the current sampling delay is compensated in a way that the compensation amount is negatively correlated with the switching frequency.
7. The variable switching frequency control method for EC wind turbines according to claim 6, characterized in that, The first interrupt frequency is a variable frequency, the second interrupt frequency is a fixed frequency, and the second interrupt frequency is independent of the first interrupt frequency.
8. A variable switching frequency control device for an EC fan, characterized in that, The method for controlling the variable switching frequency of an EC wind turbine as described in any one of claims 1 to 7 includes: The calibration unit divides the speed range of the EC fan into multiple speed segments, sets the corresponding switching frequency based on the noise characteristics of the EC fan in each speed segment, and obtains the calibration curve of the switching frequency with respect to the speed. The acquisition unit acquires the actual rotational speed of the EC fan, obtains the switching frequency corresponding to the actual rotational speed through the calibration curve, and smooths the switching frequency corresponding to the actual rotational speed to obtain the target switching frequency. The update compensation unit updates the switching frequency of the EC wind turbine through a first timer based on the target switching frequency, and executes the FOC current loop operation and sliding mode observer algorithm through a second timer to compensate for the current sampling delay.
9. An electronic device, characterized in that, The electronic device includes a processor and a memory; wherein the memory is used to store a computer program, which is loaded and executed by the processor to implement the variable switching frequency control method for the EC wind turbine as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, Used to store a computer program, which, when executed by a processor, implements the variable switching frequency control method for EC wind turbines as described in any one of claims 1 to 7.