Control methods, equipment and storage media for AC asynchronous motors

Abstract

This application belongs to the field of motor control technology, specifically relating to a control method, device, and storage medium for an AC asynchronous motor. The method involves acquiring the three-phase current of the motor at a preset acquisition cycle, and determining the direct-axis current and quadrature-axis current based on the three-phase current. In each control cycle, the state feedback quantity for the current control cycle is determined based on the direct-axis current and quadrature-axis current within that cycle. A voltage compensation quantity is determined based on the state feedback quantities from the previous and current control cycles. The voltage control quantity for the motor is determined based on the voltage compensation quantity and a reference voltage, and a drive signal is generated based on the voltage control quantity. This method enhances the ability to detect low-frequency oscillations in the AC asynchronous motor through state feedback, determines the voltage compensation quantity based on the state feedback quantities of different control cycles, and dynamically adjusts the control parameters, thereby effectively suppressing low-frequency oscillations generated during the operation of the AC asynchronous motor.

Description

Technical Field

[0001] This application belongs to the field of motor control technology, specifically relating to a control method, device, and storage medium for an AC asynchronous motor. Background Technology

[0002] AC asynchronous motors are widely used in industrial automation, HVAC, water pumps, and fans. In some applications, stable low-speed operation of AC asynchronous motors is required, and the low-frequency stability of AC asynchronous motors directly affects the operating efficiency, lifespan, and user experience of the equipment.

[0003] AC asynchronous motors are prone to low-frequency oscillations such as unstable speed or motor vibration when operating at low frequencies. Some control schemes suppress these low-frequency oscillations by setting fixed compensation parameters.

[0004] However, in actual operation, low-frequency oscillation of AC asynchronous motors is a dynamic process. Setting fixed compensation parameters is difficult to adapt to the dynamic characteristics of AC asynchronous motors and is difficult to effectively suppress low-frequency oscillation. Summary of the Invention

[0005] This application provides a control method, device, and storage medium for an AC asynchronous motor, which solves the problem that it is difficult to adapt to the dynamic characteristics of an AC asynchronous motor by setting fixed compensation parameters, and it is difficult to effectively suppress the low-frequency oscillations generated during the operation of the AC asynchronous motor.

[0006] In a first aspect, this application provides a control method for an AC asynchronous motor, comprising:

[0007] The three-phase current of the motor is acquired at a preset acquisition period, and the direct-axis current and quadrature-axis current are determined based on the three-phase current;

[0008] In each control cycle, the state feedback quantity of the current control cycle is determined based on the direct-axis current and the quadrature-axis current within the control cycle.

[0009] The voltage compensation amount is determined based on the state feedback amount of the previous control cycle and the state feedback amount of the current control cycle.

[0010] The voltage control quantity of the motor is determined based on the voltage compensation quantity and the reference voltage, and a drive signal is generated based on the voltage control quantity.

[0011] In one possible implementation, determining the state feedback quantity for the current control cycle based on the direct-axis current and the quadrature-axis current within the control cycle includes:

[0012] Extract the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control cycle;

[0013] The state feedback quantity for the current control cycle is determined based on the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current.

[0014] In one possible implementation, the control period and the preset acquisition period are the same, and the extraction of the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control period includes:

[0015] The direct-axis current within the control cycle is determined as the fluctuation characteristic quantity of the direct-axis current;

[0016] The quadrature current within the control cycle is determined as the fluctuation characteristic quantity of the quadrature current.

[0017] In one possible implementation, the control cycle includes multiple preset acquisition cycles, and the extraction of the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current within the control cycle includes:

[0018] The peak value among the multiple direct-axis currents within the control cycle is determined as the fluctuation characteristic quantity of the direct-axis current;

[0019] The peak value among the multiple quadrature-axis currents within the control cycle is determined as the fluctuation characteristic quantity of the quadrature-axis current.

[0020] In one possible implementation, determining the state feedback quantity for the current control cycle based on the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current includes:

[0021] The sum of the squares of the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current is determined as the state feedback quantity for the current control cycle.

[0022] In one possible implementation, determining the motor voltage control quantity based on the voltage compensation amount and the reference voltage includes:

[0023] The reference voltage is determined based on the current operating frequency of the motor and the voltage-frequency correspondence of the motor.

[0024] The voltage compensation limit value is determined based on the current operating frequency and the reference operating frequency of the motor. The voltage compensation limit value includes an upper limit value and a lower limit value.

[0025] The voltage control quantity is determined based on the upper limit of the amplitude limit, the lower limit of the amplitude limit, the voltage compensation amount, and the reference voltage.

[0026] In one possible implementation, determining the voltage control quantity based on the upper limit of the amplitude limiting value, the lower limit of the amplitude limiting value, the voltage compensation amount, and the reference voltage includes:

[0027] When the voltage compensation amount is between the upper limit of the amplitude limit and the lower limit of the amplitude limit, the sum of the voltage compensation amount and the reference voltage is determined as the voltage control amount;

[0028] When the voltage compensation amount is greater than or equal to the upper limit of the limiting value, the sum of the upper limit of the limiting value and the reference voltage is determined as the voltage control amount;

[0029] When the voltage compensation amount is less than or equal to the lower limit of the amplitude limit, the sum of the lower limit of the amplitude limit and the reference voltage is determined as the voltage control amount.

[0030] In one possible implementation, determining the voltage compensation limit value based on the current operating frequency and the reference operating frequency of the motor includes:

[0031] Obtain a preset maximum limiting threshold and a minimum limiting threshold, wherein the maximum limiting threshold is the rated voltage of the motor multiplied by a first coefficient, and the minimum limiting threshold is the rated voltage of the motor multiplied by a second coefficient, wherein the first coefficient is greater than the second coefficient;

[0032] Determine the ratio of the current operating frequency to the reference operating frequency of the motor;

[0033] Multiply the maximum amplitude limit threshold by the ratio to obtain the upper limit of the amplitude limit value;

[0034] Multiplying the minimum limiting threshold by the ratio yields the lower limit of the limiting value.

[0035] Secondly, this application provides a control device for an AC asynchronous motor, comprising: an acquisition module, a processing module, a determination module, and a generation module, wherein:

[0036] The acquisition module is used to acquire the three-phase current of the motor at a preset acquisition period, and determine the direct-axis current and quadrature-axis current based on the three-phase current;

[0037] The processing module is used to determine the state feedback quantity of the current control cycle based on the direct-axis current and the quadrature-axis current in each control cycle.

[0038] The determining module is used to determine the voltage compensation amount based on the state feedback amount of the previous control cycle and the state feedback amount of the current control cycle.

[0039] The generation module is used to determine the voltage control quantity of the motor based on the voltage compensation quantity and the reference voltage, and to generate a drive signal based on the voltage control quantity.

[0040] In one possible implementation, the processing module is further configured to:

[0041] Extract the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control cycle;

[0042] The state feedback quantity for the current control cycle is determined based on the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current.

[0043] In one possible implementation, the control cycle is the same as the preset acquisition cycle, and the processing module is further configured to:

[0044] The direct-axis current within the control cycle is determined as the fluctuation characteristic quantity of the direct-axis current;

[0045] The quadrature current within the control cycle is determined as the fluctuation characteristic quantity of the quadrature current.

[0046] In one possible implementation, the control cycle includes multiple preset acquisition cycles, and the processing module is further configured to:

[0047] The peak value among the multiple direct-axis currents within the control cycle is determined as the fluctuation characteristic quantity of the direct-axis current;

[0048] The peak value among the multiple quadrature-axis currents within the control cycle is determined as the fluctuation characteristic quantity of the quadrature-axis current.

[0049] In one possible implementation, the processing module is further configured to:

[0050] The sum of the squares of the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current is determined as the state feedback quantity for the current control cycle.

[0051] In one possible implementation, the generation module is further configured to:

[0052] The reference voltage is determined based on the current operating frequency of the motor and the voltage-frequency correspondence of the motor.

[0053] The voltage compensation limit value is determined based on the current operating frequency and the reference operating frequency of the motor. The voltage compensation limit value includes an upper limit value and a lower limit value.

[0054] The voltage control quantity is determined based on the upper limit of the amplitude limit, the lower limit of the amplitude limit, the voltage compensation amount, and the reference voltage.

[0055] In one possible implementation, the generation module is further configured to:

[0056] When the voltage compensation amount is between the upper limit of the amplitude limit and the lower limit of the amplitude limit, the sum of the voltage compensation amount and the reference voltage is determined as the voltage control amount;

[0057] When the voltage compensation amount is greater than or equal to the upper limit of the limiting value, the sum of the upper limit of the limiting value and the reference voltage is determined as the voltage control amount;

[0058] When the voltage compensation amount is less than or equal to the lower limit of the amplitude limit, the sum of the lower limit of the amplitude limit and the reference voltage is determined as the voltage control amount.

[0059] In one possible implementation, the generation module is further configured to:

[0060] Obtain a preset maximum limiting threshold and a minimum limiting threshold, wherein the maximum limiting threshold is the rated voltage of the motor multiplied by a first coefficient, and the minimum limiting threshold is the rated voltage of the motor multiplied by a second coefficient, wherein the first coefficient is greater than the second coefficient;

[0061] Determine the ratio of the current operating frequency to the reference operating frequency of the motor;

[0062] Multiply the maximum amplitude limit threshold by the ratio to obtain the upper limit of the amplitude limit value;

[0063] Multiplying the minimum limiting threshold by the ratio yields the lower limit of the limiting value.

[0064] Thirdly, this application provides an electronic device, the device comprising: a memory and a processor;

[0065] The memory stores computer-executed instructions;

[0066] The processor executes computer execution instructions stored in the memory, causing the processor to perform the control method for the AC asynchronous motor as described in the first aspect and / or various possible embodiments of the first aspect.

[0067] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the control method for an AC asynchronous motor as described in the first aspect and / or various possible embodiments of the first aspect.

[0068] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the control method for an AC asynchronous motor as described in the first aspect and / or various possible embodiments of the first aspect.

[0069] This application provides a control method for an AC asynchronous motor. The method acquires the three-phase current of the motor using a preset acquisition cycle and determines the direct-axis current and quadrature-axis current based on the three-phase current. In each control cycle, the state feedback quantity for the current control cycle is determined based on the direct-axis current and quadrature-axis current within the control cycle. A voltage compensation quantity is determined based on the state feedback quantity from the previous control cycle and the current control cycle. The voltage control quantity for the motor is determined based on the voltage compensation quantity and a reference voltage, and a drive signal is generated based on the voltage control quantity. This method uses both direct-axis current and quadrature-axis current to jointly determine the state feedback quantity for the current control cycle. This dual-state feedback enhances the ability to detect low-frequency oscillations in the AC asynchronous motor, achieving coordinated suppression of torque and flux oscillations. The voltage compensation quantity is determined based on the state feedback quantity of different control cycles, thereby dynamically adjusting the control parameters for different control cycles. The voltage control quantity for the motor is determined based on the voltage compensation quantity and the reference voltage, and a drive signal is generated, effectively suppressing low-frequency oscillations generated during the operation of the AC asynchronous motor. Attached Figure Description

[0070] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0071] Figure 1 A flowchart illustrating a control method for an AC asynchronous motor provided in this application embodiment. Figure 1 ;

[0072] Figure 2 A flowchart illustrating a control method for an AC asynchronous motor provided in this application embodiment. Figure 2 ;

[0073] Figure 3 A schematic diagram of the structure of a control device for an AC asynchronous motor provided in an embodiment of this application;

[0074] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0075] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0076] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0077] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0078] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0079] The constant voltage-to-frequency ratio (V / F) control method is one of the most commonly used open-loop control methods for AC asynchronous motors. It maintains a constant ratio of stator voltage to output frequency to keep the air gap flux of the AC asynchronous motor constant, thereby ensuring stable torque and normal operation of the AC asynchronous motor within its speed regulation range.

[0080] When an AC asynchronous motor operates in the low-frequency range, the amplitude of the voltage control quantity is small, and the stator resistance and line voltage drop cannot be ignored. This results in a large proportion of the stator resistance voltage drop and a decrease in back electromotive force, which weakens the system damping effect of the AC asynchronous motor and causes low-frequency oscillations in the current and speed of the AC asynchronous motor.

[0081] In related technologies, setting a fixed compensation value for the low-frequency oscillations generated during the operation of an AC asynchronous motor is difficult to adapt to the dynamic characteristic changes of the AC asynchronous motor at different frequencies, which can easily lead to insufficient low-frequency suppression or high-frequency overcompensation.

[0082] In some solutions, low-frequency oscillations in AC asynchronous motors are suppressed by controlling the quadrature-axis current. However, the quadrature-axis and direct-axis currents of an AC asynchronous motor are not completely independent. The quadrature-axis current determines the output torque of the AC asynchronous motor, while the direct-axis current determines the excitation strength. Electrical coupling exists between the quadrature-axis and direct-axis currents, and this electrical coupling is amplified under low-frequency operating conditions. When an AC asynchronous motor generates low-frequency oscillations, it is also accompanied by flux pulsation. Controlling only the quadrature-axis current cannot resolve the mutual interference and coupling between the quadrature-axis and direct-axis currents. Therefore, controlling the quadrature-axis current can only weaken the oscillation amplitude, but cannot eliminate the low-frequency coupled oscillation problem.

[0083] Furthermore, directly using proportional-integral-derivative (PID) control to suppress low-frequency oscillations presents challenges. The proportional term, being a linear amplification across the entire range, struggles to distinguish between normal current fluctuations and those caused by low-frequency oscillations. The derivative term is extremely sensitive to noise, amplifying even minute noise levels. Therefore, PID control fails to differentiate between steady-state AC signals and abnormal oscillations, making it impossible to suppress low-frequency oscillations while filtering out noise and preserving normal fluctuations.

[0084] To address the aforementioned problems, this application provides a control method for an AC asynchronous motor, which solves the problem of low-frequency oscillations generated when the AC asynchronous motor operates at low frequencies.

[0085] The execution entity in this application embodiment can be an AC asynchronous motor or a control device for an AC asynchronous motor. The control device for an AC asynchronous motor can be implemented through software and / or hardware. For example, the control device for an AC asynchronous motor can be a processor within the AC asynchronous motor.

[0086] The technical solutions of this application and how they solve the aforementioned technical problems are described in detail below with specific embodiments. These specific embodiments may exist independently or in combination with each other. Identical or similar concepts or processes may not be repeated in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0087] Figure 1 A flowchart illustrating a control method for an AC asynchronous motor provided in this application embodiment. Figure 1 .like Figure 1 As shown, the method includes:

[0088] S101. Obtain the three-phase current of the motor with a preset acquisition cycle, and determine the direct-axis current and quadrature-axis current based on the three-phase current.

[0089] The preset acquisition period is the current sampling period for acquiring the three-phase current of the motor. The preset acquisition period can be set by hardware or software with timing functions. For example, a suitable preset acquisition period can be determined by setting the clock division or pre-division coefficient through a microprocessor; or the sampling duration of the three-phase current can be determined by configuring the timer count reload value, thereby determining the preset acquisition period.

[0090] For example, Hall effect sensors can be used to collect the three-phase current of a motor. The three-phase current is the instantaneous operating current of the three-phase stator windings of the motor. It is a raw AC signal superimposed with the normal fundamental component, low-frequency oscillation pulsation, and high-frequency noise, which can directly reflect the operating status of the motor.

[0091] Direct-axis current is the excitation current component in the rotating coordinate system, which determines the magnitude of the air gap magnetic field and the excitation state of the motor. Direct-axis current corresponds to the strength of the magnetic flux. Quadrature-axis current is the torque current component in the rotating coordinate system, which determines the electromagnetic torque output of the motor. Quadrature-axis current can reflect the load fluctuations and torque pulsations of the motor.

[0092] As one implementation method, the direct-axis current and quadrature-axis current can be determined based on the three-phase current through Clark and Park transformations. The calculation process for the direct-axis current and quadrature-axis current can be as follows: First, acquire the three-phase current of the motor at a preset acquisition period. Then, the Clark transformation is performed on the three-phase currents to obtain the α current in the stationary coordinate system. and β current Finally, the electrical angle is calculated based on the current operating frequency of the motor, and the α current is then adjusted according to the electrical angle. and β current Perform the Park transformation to obtain the direct-axis current. and cross-axis current .

[0093] The three-phase current of the motor is acquired at a preset acquisition period to ensure a fixed acquisition period and synchronization with the motor's control timing. The direct-axis current is then determined based on the three-phase current. and cross-axis current It can decouple three-phase alternating current into direct-axis current. and cross-axis current This separates the flux control component and torque control component of the current in the motor, making it easier to identify low-frequency flux pulsations and torque disturbances.

[0094] S102. In each control cycle, determine the state feedback quantity of the current control cycle based on the direct-axis current and quadrature-axis current within the control cycle.

[0095] The control cycle is a fixed time interval during which the executor of the AC asynchronous motor control method performs one complete control method. The control cycle can be the same as or greater than the preset acquisition cycle.

[0096] The state feedback quantity Fbk can quantify the operating state of the motor. The state feedback quantity is determined by the direct axis current and the quadrature axis current, and can characterize the current magnetic flux stability, torque fluctuation degree or low frequency oscillation strength of the motor.

[0097] Within each control cycle, the state feedback quantity Fbk of the current control cycle is determined based on the direct-axis current and quadrature-axis current, thereby quantifying the motor operating state of each control cycle and providing a data basis for subsequent oscillation suppression.

[0098] S103. Determine the voltage compensation amount based on the status feedback amount of the previous control cycle and the status feedback amount of the current control cycle.

[0099] The state feedback quantity Fbk from the previous control cycle k-1 It can characterize the motor's flux stability, torque fluctuation, or the strength of low-frequency oscillations in the previous control cycle. The state feedback quantity Fbk for the current control cycle... k It represents the operating status of the motor within the current control cycle.

[0100] The voltage compensation amount is based on the motor's state feedback amount Fbk from the previous control cycle. k-1 and the state feedback quantity Fbk of the current control cycle k A defined voltage correction component can be used to fine-tune the control voltage of the motor.

[0101] The voltage compensation amount changes only based on the state feedback amount, which can be used to achieve high signal-to-noise ratio differential damping control, and can solve the problem that traditional PID control methods have difficulty distinguishing between steady-state AC signals and abnormal oscillations.

[0102] For example, the input error of the current control cycle can be determined based on the state feedback value of the previous control cycle and the state feedback value of the current control cycle. The input error can be calculated using the following formula:

[0103] (1)

[0104] in, It is the input error of the current control cycle.

[0105] When the motor operates stably or in a steady-state oscillation, the input error tends to zero, and no voltage compensation is required, thus avoiding malfunctions. However, when the motor's operating state changes abruptly, a significant input error occurs, and the voltage compensation amount is determined based on this input error.

[0106] For example, the voltage compensation amount can be calculated using a PID control method, and the calculation formula for the voltage compensation amount can be expressed as follows:

[0107] (2)

[0108] , It is the voltage compensation amount. It is proportional gain. It is the differential gain. It is the input error of the current control cycle. It is the input error of the previous control cycle. It's the control cycle. Proportional gain. It can be set to a larger value for faster response to changes; differential gain. It can help smooth the calculation.

[0109] The voltage compensation amount is determined by the state feedback amount of the previous control cycle and the state feedback amount of the current control cycle. The voltage compensation amount can be dynamically calculated to achieve advance suppression of low-frequency oscillations, thereby improving the stability of motor operation.

[0110] S104. Determine the voltage control quantity of the motor based on the voltage compensation quantity and the reference voltage, and generate a drive signal based on the voltage control quantity.

[0111] The reference voltage is determined from the V / F curve based on the current operating frequency and can serve as the drive signal for controlling the motor under ideal conditions. The V / F curve represents the motor's control strategy and is used to indicate the relationship between the reference voltage and the motor's current operating frequency. Controlling the motor according to the V / F curve can maintain a relatively constant voltage-to-frequency ratio, thereby ensuring a constant air gap flux in the motor.

[0112] The voltage control quantity of the motor, determined based on the voltage compensation amount and the reference voltage, can be expressed by the following formula:

[0113] (3)

[0114] in, It is a voltage compensation control quantity. It is the reference voltage. It is the voltage compensation amount.

[0115] For example, a drive signal generated based on a voltage control quantity can be used to perform an inverse Park transformation on the voltage control quantity to obtain the voltage in the stationary coordinate system. Then, for the voltage in the stationary coordinate system Space Vector Pulse Width Modulation (SVPWM) is performed to generate a drive signal, which in turn drives the motor.

[0116] The control method for an AC asynchronous motor provided in this application acquires the three-phase current of the motor with a preset acquisition cycle, and determines the direct-axis current and quadrature-axis current based on the three-phase current. In each control cycle, the state feedback quantity of the current control cycle is determined based on the direct-axis current and quadrature-axis current within the control cycle. The voltage compensation quantity is determined based on the state feedback quantity of the previous control cycle and the state feedback quantity of the current control cycle. The voltage control quantity of the motor is determined based on the voltage compensation quantity and the reference voltage, and a drive signal is generated based on the voltage control quantity. This method determines the state feedback quantity of the current control cycle by using the direct-axis current and quadrature-axis current together. Through dual-state feedback, it enhances the ability to sense low-frequency oscillations of the AC asynchronous motor, completes the coordinated suppression of torque and flux oscillations, determines the voltage compensation quantity based on the state feedback quantity of different control cycles, thereby completing the dynamic adjustment of control parameters for different control cycles to obtain the voltage compensation quantity, determines the voltage control quantity of the motor based on the voltage compensation quantity and the reference voltage, and generates a drive signal, thereby effectively suppressing the low-frequency oscillations generated during the operation of the AC asynchronous motor.

[0117] As one implementation method, determining the state feedback quantity of the current control cycle may include: extracting the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control cycle; and determining the state feedback quantity of the current control cycle based on the fluctuation characteristics of the direct-axis current and the quadrature-axis current.

[0118] In this step, fluctuation characteristics can represent features such as the amplitude or trend of current change. The fluctuation characteristics of direct-axis current are used to represent fluctuations related to the motor's magnetic flux state; the fluctuation characteristics of quadrature-axis current are used to represent fluctuations related to the motor's torque.

[0119] The state feedback quantity of the current control cycle can indicate the degree of low-frequency oscillation of the motor within the current control cycle, and can be used as the basis for determining the voltage compensation quantity.

[0120] By extracting the fluctuation characteristics of the direct-axis current and the quadrature-axis current during the control cycle, fluctuation characteristics related to magnetic flux strength and torque output are screened out. The two characteristics are then fused to obtain the state feedback quantity of the comprehensive state, which can fully reflect the oscillation characteristics of the motor and provide an effective reference for determining the voltage compensation quantity.

[0121] For example, the state feedback quantity for the current control cycle can be determined by the sum of the squares of the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current.

[0122] In this step, the sum of the squares of the fluctuation characteristics of the direct-axis current and the quadrature-axis current is determined as the state feedback quantity of the current control cycle. The fluctuation characteristics of the direct-axis current and the quadrature-axis current are squared respectively. After the square operation, the result is always a positive number, with no positive and negative cancellation. This will prevent the fluctuations from canceling each other out, thus avoiding the problem of motor oscillation state detection failure.

[0123] As one implementation method, when the control period and the preset acquisition period are the same, the direct-axis current within the control period can be determined as the fluctuation characteristic of the direct-axis current; and the quadrature-axis current within the control period can be determined as the fluctuation characteristic of the quadrature-axis current.

[0124] When the motor oscillates at low frequency, the direct-axis current and quadrature-axis current within the control cycle can contain the complete oscillation and fluctuation characteristics of magnetic flux and torque. Therefore, the direct-axis current and quadrature-axis current within the control cycle can be directly used as their respective fluctuation characteristic quantities.

[0125] The control cycle is the same as the preset acquisition cycle, which can achieve strict alignment of control timing. When the current is acquired, the control strategy is calculated synchronously, thereby ensuring the real-time performance of low-frequency oscillation suppression.

[0126] By defining the direct-axis current and the quadrature-axis current as fluctuation characteristics within the control cycle, multiple calculations can be performed without fully reflecting the fluctuations of both the direct-axis and quadrature-axis currents, thus reducing the computational load.

[0127] In one implementation, when the control period includes multiple preset acquisition periods, the peak value among multiple direct-axis currents within the control period can be determined as the fluctuation characteristic of the direct-axis current; and the peak value among multiple quadrature-axis currents within the control period can be determined as the fluctuation characteristic of the quadrature-axis current.

[0128] When the motor control cycle is longer than the preset acquisition cycle, each control cycle will include multiple acquisition cycles. For example, if the motor control cycle is 10 ms and the preset acquisition cycle is 1 ms, then each control cycle will include 10 preset acquisition cycles.

[0129] When a motor experiences low-frequency oscillations, its direct-axis and quadrature-axis currents will fluctuate periodically. The peak value among multiple direct-axis currents within the control cycle can represent the maximum deviation of the magnetic flux fluctuation, and the peak value among multiple quadrature-axis currents can represent the maximum deviation of the torque fluctuation. The magnitude of the peak value is positively correlated with the strength of the oscillation. Therefore, the peak value among multiple direct-axis currents can be used as the fluctuation characteristic of the direct-axis current, and the peak value among multiple quadrature-axis currents can be used as the fluctuation characteristic of the direct-axis current.

[0130] The control cycle includes multiple preset acquisition cycles, which can acquire multiple sets of continuous current data, thus fully capturing current fluctuations in low-frequency oscillations. This reduces control misadjustment, enhances oscillation suppression, and improves system stability. The peak value of the current reflects the maximum amplitude of the current fluctuation. By using the peak value of the current within multiple preset acquisition cycles as the fluctuation characteristic, and not relying on the instantaneous current at a single moment, it is possible to avoid misjudging noise as oscillation fluctuations.

[0131] Figure 2 A flowchart illustrating a control method for an AC asynchronous motor provided in this application embodiment. Figure 2 The following is a combination of... Figure 2 The determination of the voltage control quantity in the embodiments of this application will be described, such as... Figure 2 As shown, the method includes:

[0132] S201. Determine the reference voltage based on the current operating frequency of the motor and the voltage-frequency correspondence of the motor.

[0133] The current operating frequency of the motor determines its current speed, and this frequency can be predetermined based on the motor's operating conditions. The voltage-frequency relationship of the motor can be determined from a pre-calibrated V / F curve. From the V / F curve, the reference voltage corresponding to the motor at different operating frequencies can be determined. Therefore, the current operating frequency of the motor can be predetermined, and the reference voltage can be determined from the V / F curve based on the current operating frequency.

[0134] Based on the current operating frequency of the motor, the corresponding reference voltage is determined from the V / F curve to maintain constant magnetic flux during motor operation and improve the overall stability of motor operation.

[0135] S202. Determine the voltage compensation limit value based on the current operating frequency and the motor's reference operating frequency. The voltage compensation limit value includes an upper limit and a lower limit.

[0136] The reference operating frequency of a motor is its standard operating frequency, typically 50Hz. For a motor to operate normally, the ratio of voltage to operating frequency must remain constant; therefore, there is a certain correlation between the motor's operating frequency and voltage. Thus, the voltage compensation limit value can be determined based on the motor's current operating frequency, thereby matching the motor's characteristics at different frequencies, balancing low-speed stability and high-speed dynamics, and ultimately improving the stability of full-frequency oscillation suppression.

[0137] In this step, determining the voltage compensation limit value can be achieved by first obtaining the preset maximum and minimum limit thresholds; then determining the ratio of the current operating frequency to the motor's reference operating frequency; finally, multiplying the maximum limit threshold by the ratio to obtain the upper limit value, and multiplying the minimum limit threshold by the ratio to obtain the lower limit value. The maximum limit threshold is the motor's rated voltage multiplied by a first coefficient, and the minimum limit threshold is the motor's rated voltage multiplied by a second coefficient, where the first coefficient is greater than the second coefficient.

[0138] The voltage compensation limit can be expressed by the following formula:

[0139] (4)

[0140] (5)

[0141] in, It is the upper limit of the amplitude limit. It is the lower limit of the amplitude limit. It is the rated voltage of the motor. It is the first coefficient. It is the second coefficient. This is the current operating frequency. It is the reference operating frequency.

[0142] The voltage compensation limit can be set according to the rated voltage of the motor. For example, if the first coefficient is 0.2, the second coefficient is 0.1, the rated voltage of the motor is 380V, the current operating frequency of the motor is 40Hz, and the reference operating frequency of the motor is 50Hz, then the upper limit of the limit can be determined to be 60.8V and the lower limit is 30.4V.

[0143] The maximum and minimum voltage compensation thresholds are determined based on the motor's rated voltage to ensure that the maximum voltage compensation is within a safe range. The upper and lower limits of the voltage compensation value are dynamically determined based on the motor's current operating frequency and reference frequency. When the current operating frequency is low, the voltage compensation limit is tightened to prevent overreaction, while when the current operating frequency is high, the voltage compensation limit is relaxed to ensure dynamic response.

[0144] S203. Determine the voltage control quantity based on the upper limit of the amplitude limit, the lower limit of the amplitude limit, the voltage compensation amount, and the reference voltage.

[0145] When the voltage compensation amount is between the upper limit and the lower limit of the amplitude limit, the sum of the voltage compensation amount and the reference voltage is determined as the voltage control amount; when the voltage compensation amount is greater than or equal to the upper limit of the amplitude limit, the sum of the upper limit of the amplitude limit and the reference voltage is determined as the voltage control amount; when the voltage compensation amount is less than or equal to the lower limit of the amplitude limit, the sum of the lower limit of the amplitude limit and the reference voltage is determined as the voltage control amount.

[0146] In this step, the upper limit of the amplitude limit is used as the upper limit of the voltage compensation amount to prevent the voltage control amount from being too high and causing motor abnormalities. The lower limit of the amplitude limit is used as the lower limit of the voltage compensation amount to prevent insufficient voltage control compensation and a decrease in the low-frequency oscillation suppression effect. By setting the upper limit and lower limit of the amplitude limit, and using the limit superposition when the voltage compensation amount exceeds the upper or lower limit, the effective compensation amount is retained while the voltage adjustment range is limited, thereby improving the low-frequency oscillation suppression effect of the motor control method across the entire frequency band.

[0147] According to the embodiments of this application, the control method for AC asynchronous motors provided in this application is implemented using software algorithms, without the need to add additional sensors to monitor parameters such as motor speed, and is applicable to all general-purpose frequency converters.

[0148] Based on the above embodiments, this application also provides a control device for an AC asynchronous motor. Figure 3 This is a schematic diagram of the structure of a control device for an AC asynchronous motor provided in an embodiment of this application, as shown below. Figure 3 As shown, the AC asynchronous motor control device 300 provided in this embodiment includes: an acquisition module 301, a processing module 302, a determination module 303, and a generation module 304. Wherein:

[0149] The acquisition module 301 is used to acquire the three-phase current of the motor at a preset acquisition period, and determine the direct-axis current and quadrature-axis current based on the three-phase current;

[0150] Processing module 302 is used to determine the state feedback quantity of the current control cycle based on the direct-axis current and quadrature-axis current in each control cycle.

[0151] The determination module 303 is used to determine the voltage compensation amount based on the state feedback amount of the previous control cycle and the state feedback amount of the current control cycle.

[0152] The generation module 304 is used to determine the voltage control quantity of the motor based on the voltage compensation quantity and the reference voltage, and to generate a drive signal based on the voltage control quantity.

[0153] In one possible implementation, the processing module 302 is further configured to:

[0154] Extract the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control cycle;

[0155] The state feedback quantity for the current control cycle is determined based on the fluctuation characteristics of the direct-axis current and the quadrature-axis current.

[0156] In one possible implementation, the control cycle is the same as the preset acquisition cycle, and the processing module 302 is further configured to:

[0157] The direct-axis current within the control cycle is defined as the fluctuation characteristic quantity of the direct-axis current.

[0158] The quadrature axis current within the control period is defined as the fluctuation characteristic quantity of the quadrature axis current.

[0159] In one possible implementation, the control cycle includes multiple preset acquisition cycles, and the processing module 302 is further configured to:

[0160] The peak value among multiple direct-axis currents within the control cycle is determined as the fluctuation characteristic of the direct-axis current.

[0161] The peak value among multiple quadrature-axis currents within the control period is determined as the fluctuation characteristic quantity of the quadrature-axis current.

[0162] In one possible implementation, the processing module 302 is further configured to:

[0163] The sum of the squares of the fluctuation characteristics of the direct-axis current and the fluctuation characteristics of the quadrature-axis current is determined as the state feedback quantity for the current control cycle.

[0164] In one possible implementation, the generation module 304 is further configured to:

[0165] The reference voltage is determined based on the motor's current operating frequency and the voltage-frequency correspondence of the motor.

[0166] The voltage compensation limit is determined based on the current operating frequency and the motor's reference operating frequency. The voltage compensation limit includes an upper limit and a lower limit.

[0167] The voltage control quantity is determined based on the upper limit of the amplitude limit, the lower limit of the amplitude limit, the voltage compensation amount, and the reference voltage.

[0168] In one possible implementation, the generation module 304 is further configured to:

[0169] When the voltage compensation amount is between the upper limit and the lower limit of the amplitude limit, the sum of the voltage compensation amount and the reference voltage is determined as the voltage control amount;

[0170] When the voltage compensation is greater than or equal to the upper limit of the limit value, the sum of the upper limit of the limit value and the reference voltage is determined as the voltage control quantity.

[0171] When the voltage compensation is less than or equal to the lower limit of the amplitude limit, the sum of the lower limit of the amplitude limit and the reference voltage is determined as the voltage control quantity.

[0172] In one possible implementation, the generation module 304 is further configured to:

[0173] Obtain the preset maximum and minimum amplitude thresholds. The maximum amplitude threshold is the rated voltage of the motor multiplied by a first coefficient, and the minimum amplitude threshold is the rated voltage of the motor multiplied by a second coefficient. The first coefficient is greater than the second coefficient.

[0174] The ratio of the current operating frequency to the motor's reference operating frequency;

[0175] Multiply the maximum amplitude limit threshold by the ratio to obtain the upper limit value;

[0176] Multiply the minimum limiting threshold by the ratio to obtain the lower limit of the limiting value.

[0177] This embodiment provides a control device for an AC asynchronous motor, which can execute the control method for the AC asynchronous motor provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0178] It should be noted that the division of the various modules in the above device is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. These modules can be implemented entirely in software via processing element calls; they can be fully implemented in hardware; or some modules can be implemented in software via processing element calls, while others are implemented in hardware. Each module can be a separate processing element, or it can be integrated into a chip within the device. Alternatively, it can be stored as program code in the device's memory, and its functions can be called and executed by a processing element. Furthermore, these modules can be fully or partially integrated together, or they can be implemented independently. The processing element here can be an integrated circuit with signal processing capabilities. During implementation, each step of the above method or each of the above modules can be completed through integrated logic circuits in the processor element or through software instructions.

[0179] This application also provides an electronic device. Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 400 provided in this embodiment includes at least one processor 401 and a memory 402. Optionally, the device 400 further includes a communication component 403. The processor 401, memory 402, and communication component 403 are connected via a bus 404.

[0180] In a specific implementation, at least one processor 401 executes computer execution instructions stored in memory 402, causing at least one processor 401 to perform the above-described method.

[0181] The specific implementation process of processor 401 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0182] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0183] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0184] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0185] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0186] The aforementioned readable 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 storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0187] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0188] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0189] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0190] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0191] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0192] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described technical solution. Its implementation principle and technical effects are similar and will not be repeated here.

[0193] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0194] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A control method for an AC asynchronous motor, characterized in that, The method includes: The three-phase current of the motor is acquired at a preset acquisition period, and the direct-axis current and quadrature-axis current are determined based on the three-phase current; In each control cycle, the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control cycle are extracted; the sum of the squares of the fluctuation characteristics of the direct-axis current and the quadrature-axis current is used to determine the state feedback quantity for the current control cycle; the fluctuation characteristic of the direct-axis current is the direct-axis current, or the peak value among multiple direct-axis currents; the fluctuation characteristic of the quadrature-axis current is the quadrature-axis current, or the peak value among multiple quadrature-axis currents; Based on the state feedback quantity of the previous control cycle and the state feedback quantity of the current control cycle, determine the input error of the current control cycle; Based on the input error of the current control cycle, the voltage compensation amount is determined according to the following formula; , It is the voltage compensation amount. It is proportional gain. It is the differential gain. It is the input error of the current control cycle. It is the input error of the previous control cycle. It is the control cycle; The reference voltage is determined based on the current operating frequency of the motor and the voltage-frequency correspondence of the motor. The voltage compensation limit value is determined based on the current operating frequency and the reference operating frequency of the motor. The voltage compensation limit value includes an upper limit value and a lower limit value. When the voltage compensation amount is between the upper limit of the amplitude limit and the lower limit of the amplitude limit, the sum of the voltage compensation amount and the reference voltage is determined as the voltage control amount; When the voltage compensation amount is greater than or equal to the upper limit of the limiting value, the sum of the upper limit of the limiting value and the reference voltage is determined as the voltage control amount; When the voltage compensation amount is less than or equal to the lower limit of the amplitude limit, the sum of the lower limit of the amplitude limit and the reference voltage is determined as the voltage control amount of the motor, and a drive signal is generated based on the voltage control amount.

2. The method according to claim 1, characterized in that, The control period is the same as the preset acquisition period. Extracting the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control period includes: The direct-axis current within the control cycle is determined as the fluctuation characteristic quantity of the direct-axis current; The quadrature current within the control cycle is determined as the fluctuation characteristic quantity of the quadrature current.

3. The method according to claim 1, characterized in that, The control cycle includes multiple preset acquisition cycles, and the extraction of the fluctuation characteristics of the direct-axis current and the quadrature-axis current within the control cycle includes: The peak value among the multiple direct-axis currents within the control cycle is determined as the fluctuation characteristic quantity of the direct-axis current; The peak value among the multiple quadrature-axis currents within the control cycle is determined as the fluctuation characteristic quantity of the quadrature-axis current.

4. The method according to claim 1, characterized in that, The step of determining the voltage compensation limit value based on the current operating frequency and the reference operating frequency of the motor includes: Obtain a preset maximum limiting threshold and a minimum limiting threshold, wherein the maximum limiting threshold is the rated voltage of the motor multiplied by a first coefficient, and the minimum limiting threshold is the rated voltage of the motor multiplied by a second coefficient, wherein the first coefficient is greater than the second coefficient; Determine the ratio of the current operating frequency to the reference operating frequency of the motor; Multiply the maximum amplitude limit threshold by the ratio to obtain the upper limit of the amplitude limit value; Multiplying the minimum limiting threshold by the ratio yields the lower limit of the limiting value.

5. An electronic device, characterized in that, The device includes: a memory and a processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the control method for an AC asynchronous motor as described in any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the control method for an AC asynchronous motor as described in any one of claims 1 to 4.

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