A constant-voltage-frequency-ratio control method, device, equipment and medium

Abstract

The application discloses a constant voltage-to-frequency ratio control method and device, equipment and a medium, and relates to the technical field of asynchronous motors. The method comprises the following steps: sampling three-phase currents of the motor, obtaining a voltage orientation angle by integrating a given frequency, and transforming the currents to a two-phase rotating coordinate system by using the voltage orientation angle to decouple active current feedback components and reactive current feedback components; after generating a total voltage given value according to a constant voltage-to-frequency ratio, establishing a voltage closed-loop control loop to output a reactive current instruction; establishing a reactive current closed-loop control loop to output a quadrature-axis voltage given value; deducting the quadrature-axis voltage given value from the total voltage given value to obtain a direct-axis voltage given value; synthesizing a space voltage vector based on the direct-axis voltage given value and the quadrature-axis voltage given value, and feeding back the amplitude of the space voltage vector to the voltage closed loop. The application effectively suppresses low-frequency oscillation and improves the output voltage precision while maintaining a simple structure through double closed-loop control of the voltage and the reactive current.

Description

A constant voltage-frequency ratio control method, device, equipment and medium Technical Field

[0001] This invention relates to the field of asynchronous motor technology, and in particular to a constant voltage-frequency ratio control method, device, equipment, and medium. Background Technology

[0002] In the field of AC motor drives, asynchronous motors are widely used in high-voltage, high-power industrial applications such as fans and pumps due to their robust structure, ease of maintenance, and relatively low cost. Constant voltage-frequency ratio control, as a basic and easily implemented control strategy, adjusts motor speed and torque by maintaining a constant ratio between motor voltage and frequency. It does not rely on complex motor parameter identification and real-time observation algorithms, thus becoming the preferred solution for many loads that do not have high requirements for dynamic performance but prioritize system reliability and economy.

[0003] However, as power levels increase, the inherent open-loop or simple closed-loop characteristics of constant voltage-frequency ratio control gradually reveal their limitations. During the operation of high-power asynchronous motors, the system is prone to continuous or intermittent low-frequency oscillations, which not only affect transmission smoothness and equipment lifespan but may also threaten the stability of the entire power system. To address this issue, existing technologies typically employ the introduction of bandpass filters. These filters aim to extract specific frequency fluctuation components of the reactive current from the detection signal and use them as compensation signals to fine-tune a given frequency, thereby attempting to increase the system's equivalent damping and suppress oscillations.

[0004] While the aforementioned frequency compensation methods based on bandpass filters can alleviate oscillation problems under certain operating conditions, their suppression effectiveness largely depends on the degree of matching between the filter parameters and the oscillation frequency. In diverse real-world operating conditions characterized by drastic load changes, complex power grid conditions, or motor parameter drift due to factors such as temperature rise, fixed filter characteristics often fail to adapt, resulting in poor oscillation suppression and potentially introducing new instability factors. Therefore, existing technical solutions still exhibit insufficient robustness and adaptability when facing complex and ever-changing industrial operating environments. Summary of the Invention

[0005] This invention provides a constant voltage-frequency ratio control method, device, equipment, and medium. The technical problem it aims to solve is: how to provide an effective control method that can more directly, proactively, and adaptably suppress low-frequency oscillations caused by reactive current fluctuations and simultaneously improve the output voltage control accuracy, while retaining the core advantages of constant voltage-frequency ratio control such as simple structure and ease of engineering implementation.

[0006] In a first aspect, embodiments of the present invention provide a constant voltage-frequency ratio control method for an asynchronous motor, comprising:

[0007] The three-phase stator current of the asynchronous motor is detected to obtain the three-phase current sampling value;

[0008] The voltage orientation angle in the voltage synchronous rotating coordinate system is obtained by integrating the given frequency of the controller.

[0009] The voltage orientation angle is used to transform the three-phase current sampling values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, so as to obtain the active current feedback component and reactive current feedback component in the two-phase rotating coordinate system.

[0010] Based on the current motor operating frequency and the preset constant voltage-frequency ratio, a total voltage setpoint is generated;

[0011] A voltage closed-loop control circuit is established, the total voltage setpoint is compared with the amplitude of the actual output voltage of the motor and proportional-integral adjustment is performed, and the output is used as the reactive current command value.

[0012] Establish a reactive current closed-loop control circuit, compare the reactive current command value with the reactive current feedback component and adjust it proportionally and integrally, and output the quadrature axis voltage setpoint.

[0013] Subtracting the quadrature-axis voltage setpoint from the total voltage setpoint yields the direct-axis voltage setpoint.

[0014] Based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of the voltage vector is fed back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor.

[0015] Optionally, the step of integrating the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system includes:

[0016] The given frequency is continuously integrated over time, and the resulting integrated angle is used as the voltage orientation angle.

[0017] Optionally, generating the total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio includes:

[0018] The starting voltage and slope are set according to the rated parameters of the asynchronous motor. During the acceleration or deceleration of the asynchronous motor, the total voltage setpoint is made to increase or decrease linearly with the current motor operating frequency according to the slope until the rated operating point is reached.

[0019] Optionally, establishing a voltage closed-loop control circuit, comparing the total voltage setpoint with the amplitude of the actual motor output voltage and performing proportional-integral adjustment, outputting as a reactive current command value, includes:

[0020] Calculate the first deviation between the total voltage setpoint and the amplitude of the actual output voltage of the motor; input the first deviation to a preset first proportional-integral regulator for calculation; and use the output value of the first proportional-integral regulator as the reactive current command value.

[0021] Optionally, the step of establishing a reactive current closed-loop control circuit, comparing the reactive current command value with the reactive current feedback component and performing proportional-integral adjustment, and outputting a quadrature-axis voltage setpoint includes:

[0022] Calculate the second deviation between the reactive current command value and the reactive current feedback component; input the second deviation to a preset second proportional-integral regulator for calculation; and use the output value of the second proportional-integral regulator as the quadrature-axis voltage setpoint.

[0023] Optionally, the step of synthesizing a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint includes:

[0024] Using the direct-axis voltage setpoint and the quadrature-axis voltage setpoint as rectangular coordinate components, calculate the magnitude of the voltage vector and its direction angle relative to the direct-axis voltage setpoint; add the direction angle to the voltage orientation angle to obtain the final phase angle of the voltage vector.

[0025] Optionally, feeding back the amplitude of the voltage vector as the amplitude of the actual output voltage of the motor to the voltage closed-loop control loop includes:

[0026] In each pulse width modulation control cycle, the amplitude of the voltage vector is calculated and updated in real time based on the direct-axis voltage setpoint and quadrature-axis voltage setpoint obtained from the pulse width modulation control cycle. The updated amplitude of the voltage vector is used as the amplitude of the actual output voltage of the motor for voltage closed-loop regulation calculation in the next pulse width modulation control cycle.

[0027] Secondly, embodiments of the present invention also provide a constant voltage-frequency ratio control device for an asynchronous motor, which includes a unit for performing the above-described method.

[0028] Thirdly, embodiments of the present invention also provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described method.

[0029] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the above-described method.

[0030] This invention provides a constant voltage-frequency ratio control method, apparatus, device, and medium. The method includes: detecting the three-phase stator current of an asynchronous motor to obtain three-phase current sample values; performing an integral operation on a given frequency of the controller to obtain a voltage orientation angle in a voltage synchronous rotating coordinate system; using the voltage orientation angle to transform the three-phase current sample values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system referenced by the voltage orientation angle, obtaining active current feedback components and reactive current feedback components in the two-phase rotating coordinate system; generating a total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio relationship; and establishing a voltage closed-loop control loop to control the total voltage setpoint. The reactive current command value is compared with the amplitude of the actual output voltage of the motor and adjusted proportionally and integrally to output the reactive current command value. A reactive current closed-loop control loop is established, and the reactive current command value is compared with the reactive current feedback component and adjusted proportionally and integrally to output the quadrature-axis voltage setpoint. The quadrature-axis voltage setpoint is subtracted from the total voltage setpoint to obtain the direct-axis voltage setpoint. Based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of the voltage vector is fed back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor. This invention effectively solves the problems of low-frequency oscillation and inaccurate output voltage that are prone to occur in traditional methods under complex operating conditions by introducing a dual closed-loop structure combining voltage closed-loop control and reactive current closed-loop control in constant voltage-frequency ratio control. The voltage closed-loop control loop achieves precise closed-loop control of the output voltage by dynamically adjusting the reactive current command, ensuring voltage accuracy. The reactive current closed-loop control circuit rapidly tracks and strongly suppresses commands, directly curbing reactive component fluctuations that cause oscillations at their source, and significantly enhancing system damping and dynamic stability. This method, while maintaining its structural simplicity, provides a more direct, proactive, and adaptable high-performance control scheme. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 is a flowchart illustrating a constant voltage-frequency ratio control method for an asynchronous motor provided in an embodiment of the present invention;

[0033] Figure 2 is a schematic block diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0034] 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, not all, of the embodiments of the present invention. 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.

[0035] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0036] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0039] Please refer to Figure 1. This embodiment of the invention provides a constant voltage-frequency ratio control method for an asynchronous motor. By introducing an inner loop with reactive current as the controlled object and an outer loop with output voltage as the controlled object on the basis of the traditional open-loop structure, a set of cooperative dual closed-loop control systems is constructed. This effectively solves the technical problems of low-frequency oscillation and insufficient output voltage accuracy in constant voltage-frequency ratio control systems under high power or complex operating conditions. Specifically, the method includes the following steps:

[0040] S1 detects the three-phase stator current of the asynchronous motor to obtain the three-phase current sampling value.

[0041] In practice, the three-phase stator current of the asynchronous motor is detected to obtain the three-phase current sampling value. Specifically, the signal is acquired by a three-phase current sensor or sampling resistor network connected to the stator side of the motor, and then converted into a digital quantity by an analog-to-digital converter.

[0042] In this embodiment of the invention, by detecting the three-phase stator current of the asynchronous motor and obtaining the sampled value, the necessary real-time information input is provided for realizing closed-loop control based on current feedback.

[0043] S2, perform an integral operation on the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system.

[0044] In practice, the given frequency of the controller is integrated to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system. This calculation is performed by integrating the given frequency over time.

[0045] In this embodiment of the invention, an integral operation is performed on a given frequency to generate a voltage orientation angle, which establishes a spatial reference for a rotating coordinate system synchronized with the fundamental frequency of the power supply.

[0046] In some preferred embodiments, the step of integrating the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system includes: performing continuous-time integration on the given frequency and using the obtained integrated angle as the voltage orientation angle.

[0047] In practice, the angular frequency corresponding to the given frequency is integrated over continuous time. The specific calculation formula is θ=∫fdt, where f is the given frequency of the controller and t represents time.

[0048] This embodiment provides a specific method for generating the voltage orientation angle. By integrating over a given frequency, a continuously changing phase reference is obtained. This voltage orientation angle is the basis for establishing a rotating coordinate system synchronized with the power supply frequency, ensuring the correctness of subsequent coordinate transformations, enabling decoupled current control, and serving as a prerequisite for implementing the entire vector control strategy.

[0049] S3, using the voltage orientation angle, transform the three-phase current sampling values ​​from the three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, to obtain the active current feedback component and reactive current feedback component in the two-phase rotating coordinate system.

[0050] In practice, the calculated voltage orientation angle is used to perform a coordinate transformation on the three-phase current sampling values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system. The direct axis of the two-phase rotating coordinate system coincides with the direction of the voltage orientation angle. Through this transformation, the active current feedback component that is consistent with the voltage direction and the reactive current feedback component that is orthogonal to it are separated.

[0051] In this embodiment of the invention, the voltage orientation angle is used to transform the three-phase current, thereby decoupling the AC current in the stationary coordinate system into a direct-axis current component and a quadrature-axis current component in the rotating coordinate system. The quadrature-axis current component corresponds to the reactive current orthogonal to the voltage vector. This step separates the originally coupled current variables, thus creating conditions for the independent and precise control of the reactive current component.

[0052] S4 generates the total voltage setpoint based on the current motor operating frequency and the preset constant voltage-frequency ratio.

[0053] In practice, the corresponding total voltage setpoint is generated based on the current motor operating frequency and the preset constant voltage-frequency ratio.

[0054] The preset constant voltage-frequency ratio refers to a definite correspondence established between the motor's operating frequency and the fundamental voltage amplitude applied to its stator windings according to pre-set rules throughout the entire speed control process of the motor. This constant voltage-frequency ratio typically manifests as a preset curve consisting of an initial voltage compensation segment and a linear change segment. Its specific parameters are set according to the motor's rated voltage, rated frequency, and low-speed compensation requirements, and serve as the direct basis for generating the total voltage setpoint in the control algorithm.

[0055] Specifically, in some preferred embodiments, generating the total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio includes: setting the starting voltage and slope according to the rated parameters of the asynchronous motor; and during the acceleration or deceleration of the asynchronous motor, making the total voltage setpoint linearly increase or decrease with the current motor operating frequency according to the slope until the rated operating point is reached.

[0056] In practice, the initial voltage and slope are set according to the rated parameters of the asynchronous motor. During motor acceleration or deceleration, the total voltage setpoint U_ref is generated linearly based on the current motor operating frequency f. The specific formula is U_ref = U_boost + K * f. Here, U_boost is the preset initial voltage used to compensate for the influence of stator resistance at low frequencies; K is the slope of the constant voltage-frequency ratio curve, which characterizes the rate of change of stator voltage with operating frequency during motor speed regulation.

[0057] This embodiment generates voltage commands through a linear constant voltage-frequency ratio, maintaining an approximately constant air gap flux during motor speed regulation. The compensation of the initial voltage enhances the motor's torque output capability in the low-speed region, while the linear voltage-frequency relationship ensures smooth operation of the motor from startup to its rated speed range, providing a stable and reasonable fundamental voltage excitation for the entire control system.

[0058] S5, establish a voltage closed-loop control circuit, compare the total voltage setpoint with the amplitude of the actual output voltage of the motor and adjust it proportionally and integrally, and output it as the reactive current command value.

[0059] In specific implementation, a voltage closed-loop control circuit is established. The process is as follows: the difference between the above total voltage setpoint and the amplitude of the actual output voltage of the motor is fed back. The resulting deviation signal is processed by a proportional-integral regulator. The output value of the proportional-integral regulator is set as the reactive current command value.

[0060] In this embodiment of the invention, a voltage closed-loop control loop is established based on generating a total voltage setpoint to maintain the basic magnetic flux constant of the motor. This voltage closed-loop control loop compares the total voltage setpoint with the amplitude of the actual output voltage of the motor and generates a reactive current command value through a proportional-integral regulator. When the actual output voltage deviates from the setpoint due to factors such as load variations, the voltage closed loop automatically corrects the reactive current command, aiming to correct the terminal voltage by changing the motor's excitation state. This fundamentally changes the open-loop nature of traditional methods, realizing active, closed-loop regulation of the output voltage, thereby significantly improving the stability and accuracy of the output voltage under various load conditions.

[0061] In some preferred embodiments, establishing a voltage closed-loop control circuit, comparing the total voltage setpoint with the amplitude of the actual output voltage of the motor and performing proportional-integral regulation, and outputting the result as a reactive current command value, includes: calculating a first deviation between the total voltage setpoint and the amplitude of the actual output voltage of the motor; inputting the first deviation to a preset first proportional-integral regulator for calculation; and using the output value of the first proportional-integral regulator as the reactive current command value.

[0062] In practice, the first deviation between the total voltage setpoint U_ref and the amplitude U_fdb of the actual motor output voltage is calculated, i.e., ΔU = U_ref - U_fdb. This first deviation ΔU is input to a preset first proportional-integral (PI) regulator for calculation. The output of the first PI regulator is the reactive current command value Iq_ref, where Iq_ref = K. pu ΔU+K iu ΔU / s; where K pu K is the proportional coefficient of the first proportional-integral controller. iu is the integral coefficient of the first proportional-integral regulator, and s is the Laplace operator.

[0063] This embodiment achieves voltage closed-loop regulation through a first proportional-integral regulator. The proportional element provides fast response, while the integral element eliminates static errors. This closed loop can automatically detect and correct deviations in the output voltage from the given value, such as voltage drops caused by increased load, thereby ensuring that the motor terminal voltage remains highly stable under different operating conditions, significantly improving the system's voltage regulation and load stability.

[0064] S6, establish a reactive current closed-loop control circuit, compare the reactive current command value with the reactive current feedback component and adjust it proportionally and integrally, and output the quadrature-axis voltage setpoint.

[0065] In specific implementation, a reactive current closed-loop control circuit is established. The process is as follows: the reactive current command value is subtracted from the reactive current component fed back from the motor, and the resulting deviation signal is processed by another proportional-integral regulator. The output value of the proportional-integral regulator is the quadrature-axis voltage setpoint.

[0066] In this embodiment of the invention, establishing a reactive current closed-loop control loop is the direct means to suppress low-frequency oscillations. This reactive current closed-loop control loop compares the reactive current command value output by the voltage loop with the reactive current component fed back in real time through coordinate transformation, performs proportional-integral adjustment, and outputs a quadrature-axis voltage setpoint. This reactive current closed-loop control loop can force the actual reactive current to quickly and accurately track its command value with extremely high response speed. Since theoretical analysis and practical experience both show that the low-frequency oscillations of the asynchronous motor under constant voltage-frequency ratio control mainly originate from the periodic fluctuations of the reactive component, applying strong closed-loop control to the reactive current is equivalent to introducing a high-performance damper that can actively suppress these fluctuations into the system. Regardless of whether the disturbance source is a sudden load change or grid fluctuation, this current loop can act quickly to quell the reactive oscillations, thereby fundamentally enhancing the dynamic stability of the system and overcoming the limitations of existing technologies that use passive filters for frequency compensation with poor suppression effects under certain complex operating conditions.

[0067] In some preferred embodiments, establishing a reactive current closed-loop control circuit, comparing the reactive current command value with the reactive current feedback component and performing proportional-integral adjustment to output a quadrature-axis voltage setpoint, includes: calculating a second deviation between the reactive current command value and the reactive current feedback component; inputting the second deviation to a preset second proportional-integral regulator for calculation; and using the output value of the second proportional-integral regulator as the quadrature-axis voltage setpoint.

[0068] In practice, the second deviation between the reactive current command value Iq_ref and the reactive current feedback component iq is calculated, i.e., ΔI = Iq_ref - iq. This second deviation ΔI is then input to a preset second proportional-integral (PI) regulator for calculation. The output of the second PI regulator is the quadrature-axis voltage setpoint Uq.

[0069] Where, Uq=K pi ΔI+K ii ΔI / s, K pi K is the proportional coefficient of the second proportional-integral controller. ii is the integral coefficient of the second proportional-integral regulator, and s is the Laplace operator.

[0070] This embodiment achieves direct and powerful control of reactive power components by constructing a fast reactive current closed-loop. This reactive current closed-loop control circuit can respond instantaneously to commands and disturbances, forcing the actual reactive current to closely follow the commanded value. Since system oscillations are strongly correlated with reactive current fluctuations, this fast closed-loop is equivalent to injecting adjustable damping into the system's electromagnetic energy exchange channel, which can promptly quell reactive oscillations and fundamentally enhance the system stability in the mid-to-low frequency range.

[0071] S7, subtract the quadrature-axis voltage setpoint from the total voltage setpoint to obtain the direct-axis voltage setpoint.

[0072] In practice, the direct-axis voltage setpoint is obtained by subtracting the quadrature-axis voltage setpoint from the total voltage setpoint.

[0073] S8. Based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of the voltage vector is fed back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor.

[0074] In practice, a voltage vector for space vector pulse width modulation is calculated based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint. The amplitude of this voltage vector is obtained by taking the square root of the sum of the squares of its two rectangular coordinate components. The calculated amplitude is directly used as the amplitude of the actual output voltage of the motor and fed back to the input of the voltage closed-loop control loop to close the control loop.

[0075] In this embodiment of the invention, the final driven voltage space vector is synthesized based on the direct-axis and quadrature-axis voltage setpoints, and its amplitude is fed back to the voltage closed-loop input, thus forming a complete closed-loop control link from command to feedback. This feedback mechanism makes the entire system an organic whole. The outer voltage loop is responsible for maintaining macroscopic voltage accuracy, while the inner current loop is responsible for stabilizing microscopic reactive power components. The two work together to achieve a balance between static accuracy and dynamic stability.

[0076] This embodiment solves the system instability problem caused by reactive component oscillations in traditional constant voltage-frequency ratio control by constructing a dual closed-loop structure combining an outer voltage loop and an inner reactive current loop. The voltage closed-loop control loop dynamically adjusts the commanded value of the reactive current by comparing the given voltage with the actual output voltage. This mechanism ensures that the output voltage accurately tracks its given value under different load conditions, overcoming the insufficient voltage accuracy caused by stator impedance voltage drop under open-loop control. The reactive current closed-loop control loop rapidly tracks and adjusts the commanded value. Its ability to directly control the reactive component provides active damping for the system, effectively suppressing low-frequency oscillations. The two closed loops work together to significantly improve the system's dynamic stability and disturbance rejection capability while ensuring voltage control accuracy.

[0077] In some preferred embodiments, the step of synthesizing a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint includes: using the direct-axis voltage setpoint and the quadrature-axis voltage setpoint as rectangular coordinate components, calculating the magnitude of the voltage vector and its direction angle relative to the direct-axis voltage setpoint; and adding the direction angle to the voltage orientation angle to obtain the final phase angle of the voltage vector.

[0078] In practice, the direct-axis voltage setpoint Ud and the quadrature-axis voltage setpoint Uq are used as rectangular coordinate components. First, the magnitude of the voltage vector U_fdb is calculated using the formula U_fdb = √(Ud² + Uq²). Then, the direction angle φ of the voltage vector relative to the direct axis is calculated using the formula φ = arctan(Uq / Ud). Finally, the direction angle φ is added to the voltage orientation angle θ to obtain the final phase angle θ_v = θ + φ of the voltage vector used for space vector pulse width modulation.

[0079] This embodiment completes the conversion from control input to execution input. By calculating the amplitude and phase of the synthesized voltage, the orthogonal axis voltage component output by the control algorithm is converted into the modulation information required by the inverter. The amplitude U_fdb serves as a feedback closed voltage loop, and the phase angle θ_v ensures that the output voltage vector has the correct spatial position.

[0080] In some preferred embodiments, feeding back the amplitude of the voltage vector as the amplitude of the actual output voltage of the motor to the voltage closed-loop control loop includes: in each pulse width modulation control cycle, calculating and updating the amplitude of the voltage vector in real time based on the direct-axis voltage setpoint and quadrature-axis voltage setpoint calculated in the pulse width modulation control cycle, and using the updated amplitude of the voltage vector as the amplitude of the actual output voltage of the motor for voltage closed-loop adjustment calculation in the next pulse width modulation control cycle.

[0081] In specific implementation, within each pulse width modulation control cycle, based on the direct-axis voltage setpoint Ud(k) and quadrature-axis voltage setpoint Uq(k) calculated for that cycle, the voltage is applied according to the formula U_fdb(k)=√(Ud(k)). 2 +Uq(k) 2 The amplitude of the voltage vector is calculated in real time. Here, k represents the index of the current pulse width modulation control cycle. Subsequently, this updated amplitude U_fdb(k) is immediately used as the amplitude of the actual output voltage of the motor, and provided for the voltage closed-loop regulation calculation in the next pulse width modulation control cycle (cycle k+1).

[0082] This embodiment specifies that the voltage feedback signal is based on the aforementioned synthesized voltage vector and is updated synchronously with a pulse width modulation frequency. This design ensures that the information fed back to the outer voltage loop has the highest timeliness and is completely synchronized with the current control output. It minimizes the delay of the feedback channel, allowing the voltage closed loop to adjust based on the latest system state, thereby improving the overall response speed and control real-time performance of the dual closed-loop system, and has a clear benefit for suppressing high-frequency disturbances and optimizing dynamic processes.

[0083] This invention proposes a constant voltage-frequency ratio control method for an asynchronous motor, comprising: detecting the three-phase stator current of the asynchronous motor to obtain three-phase current sample values; performing an integral operation on the given frequency of the controller to obtain a voltage orientation angle in a voltage synchronous rotating coordinate system; using the voltage orientation angle to transform the three-phase current sample values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, to obtain an active current feedback component and a reactive current feedback component in the two-phase rotating coordinate system; generating a total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio relationship; and establishing a voltage closed-loop control circuit. The invention employs a dual-loop control system, combining a voltage closed-loop control loop and a reactive current closed-loop control loop in constant voltage-frequency ratio control. This system effectively solves the problems of low-frequency oscillation and inaccurate output voltage that easily occur under complex operating conditions in traditional methods. The voltage closed-loop control loop achieves precise closed-loop control of the output voltage by dynamically adjusting the reactive current command. A reactive current closed-loop control circuit is established, where the reactive current command value is compared with the reactive current feedback component, and proportional-integral adjustment is performed to output a quadrature-axis voltage setpoint. The quadrature-axis voltage setpoint is subtracted from the total voltage setpoint to obtain the direct-axis voltage setpoint. Based on the direct-axis and quadrature-axis voltage setpoints, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of this voltage vector is fed back to the voltage closed-loop control circuit as the amplitude of the actual motor output voltage. The reactive current closed-loop control circuit rapidly tracks and strongly suppresses commands, directly curbing reactive component fluctuations that cause oscillations at their source, and significantly enhancing system damping and dynamic stability. This method, while maintaining its structural simplicity, provides a more direct, proactive, and adaptable high-performance control scheme.

[0084] Corresponding to the above-described constant voltage-frequency ratio control method for asynchronous motors, the present invention also provides a constant voltage-frequency ratio control device for asynchronous motors. This device includes a unit for executing the aforementioned constant voltage-frequency ratio control method for asynchronous motors, and can be configured in a terminal or server. Specifically, the device includes:

[0085] The detection unit is used to detect the three-phase stator current of the asynchronous motor in order to obtain the three-phase current sampling value;

[0086] The integrator unit is used to perform integration calculations on the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system;

[0087] The transformation unit is used to transform the three-phase current sampled values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, using the voltage orientation angle to obtain the active current feedback component and reactive current feedback component in the two-phase rotating coordinate system.

[0088] The generation unit is used to generate the total voltage setpoint based on the current motor operating frequency and the preset constant voltage-frequency ratio relationship;

[0089] The voltage closed-loop control unit is used to establish a voltage closed-loop control loop, compare the total voltage setpoint with the amplitude of the actual output voltage of the motor and perform proportional-integral adjustment, and output as a reactive current command value.

[0090] The current closed-loop control unit is used to establish a reactive current closed-loop control loop, compare the reactive current command value with the reactive current feedback component and perform proportional-integral adjustment, and output the quadrature-axis voltage setpoint.

[0091] The calculation unit is used to subtract the quadrature-axis voltage setpoint from the total voltage setpoint to obtain the direct-axis voltage setpoint;

[0092] The synthesis unit is used to synthesize a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, and feed the amplitude of the voltage vector back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor.

[0093] In some preferred embodiments, the step of integrating the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system includes:

[0094] The given frequency is continuously integrated over time, and the resulting integrated angle is used as the voltage orientation angle.

[0095] In some preferred embodiments, generating the total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio includes:

[0096] The starting voltage and slope are set according to the rated parameters of the asynchronous motor. During the acceleration or deceleration of the asynchronous motor, the total voltage setpoint is made to increase or decrease linearly with the current motor operating frequency according to the slope until the rated operating point is reached.

[0097] In some preferred embodiments, establishing a voltage closed-loop control circuit, comparing the total voltage setpoint with the amplitude of the actual motor output voltage and performing proportional-integral adjustment, and outputting it as a reactive current command value, includes:

[0098] Calculate the first deviation between the total voltage setpoint and the amplitude of the actual output voltage of the motor; input the first deviation to a preset first proportional-integral regulator for calculation; and use the output value of the first proportional-integral regulator as the reactive current command value.

[0099] In some preferred embodiments, establishing a reactive current closed-loop control circuit, comparing the reactive current command value with the reactive current feedback component and performing proportional-integral adjustment, and outputting a quadrature-axis voltage setpoint includes:

[0100] Calculate the second deviation between the reactive current command value and the reactive current feedback component; input the second deviation to a preset second proportional-integral regulator for calculation; and use the output value of the second proportional-integral regulator as the quadrature-axis voltage setpoint.

[0101] In some preferred embodiments, the synthesis of a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint includes:

[0102] Using the direct-axis voltage setpoint and the quadrature-axis voltage setpoint as rectangular coordinate components, calculate the magnitude of the voltage vector and its direction angle relative to the direct-axis voltage setpoint; add the direction angle to the voltage orientation angle to obtain the final phase angle of the voltage vector.

[0103] In some preferred embodiments, feeding back the amplitude of the voltage vector as the amplitude of the actual output voltage of the motor to the voltage closed-loop control loop includes:

[0104] In each pulse width modulation control cycle, the amplitude of the voltage vector is calculated and updated in real time based on the direct-axis voltage setpoint and quadrature-axis voltage setpoint obtained from the pulse width modulation control cycle. The updated amplitude of the voltage vector is used as the amplitude of the actual output voltage of the motor for voltage closed-loop regulation calculation in the next pulse width modulation control cycle.

[0105] It should be noted that those skilled in the art can clearly understand that the specific implementation process of the above-mentioned constant voltage-frequency ratio control device for asynchronous motors and each unit can be referred to the corresponding description in the foregoing method embodiments. For the sake of convenience and brevity, it will not be repeated here.

[0106] The constant voltage-frequency ratio control device for the aforementioned asynchronous motor can be implemented as a computer program, which can run on the computer device shown in Figure 2.

[0107] Please refer to Figure 2, which is a schematic block diagram of a computer device provided in an embodiment of this application. The computer device 500 can be a terminal or a server, wherein the server can be a standalone server or a server cluster composed of multiple servers.

[0108] The computer device 500 includes a processor 502, a memory, and a network interface 505 connected via a system bus 501. The memory may include a non-volatile storage medium 503 and internal memory 504.

[0109] The non-volatile storage medium 503 can store an operating system 5031 and a computer program 5032. When the computer program 5032 is executed, it causes the processor 502 to execute a constant voltage-frequency ratio control method for an asynchronous motor.

[0110] The processor 502 provides computing and control capabilities to support the operation of the entire computer device 500.

[0111] The internal memory 504 provides an environment for the operation of the computer program 5032 in the non-volatile storage medium 503. When the computer program 5032 is executed by the processor 502, the processor 502 can execute a constant voltage-frequency ratio control method for an asynchronous motor.

[0112] The network interface 505 is used for network communication with other devices. Those skilled in the art will understand that the above structure is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device 500 to which the present application is applied. A specific computer device 500 may include more or fewer components than shown in the figures, or combine certain components, or have different component arrangements.

[0113] The processor 502 is used to run a computer program 5032 stored in the memory to perform the following steps:

[0114] The three-phase stator current of the asynchronous motor is detected to obtain the three-phase current sampling value;

[0115] The voltage orientation angle in the voltage synchronous rotating coordinate system is obtained by integrating the given frequency of the controller.

[0116] The voltage orientation angle is used to transform the three-phase current sampling values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, so as to obtain the active current feedback component and reactive current feedback component in the two-phase rotating coordinate system.

[0117] Based on the current motor operating frequency and the preset constant voltage-frequency ratio, a total voltage setpoint is generated;

[0118] A voltage closed-loop control circuit is established, the total voltage setpoint is compared with the amplitude of the actual output voltage of the motor and proportional-integral adjustment is performed, and the output is used as the reactive current command value.

[0119] Establish a reactive current closed-loop control circuit, compare the reactive current command value with the reactive current feedback component and adjust it proportionally and integrally, and output the quadrature axis voltage setpoint.

[0120] Subtracting the quadrature-axis voltage setpoint from the total voltage setpoint yields the direct-axis voltage setpoint.

[0121] Based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of the voltage vector is fed back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor.

[0122] In some preferred embodiments, the step of integrating the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system includes:

[0123] The given frequency is continuously integrated over time, and the resulting integrated angle is used as the voltage orientation angle.

[0124] In some preferred embodiments, generating the total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio includes:

[0125] The starting voltage and slope are set according to the rated parameters of the asynchronous motor. During the acceleration or deceleration of the asynchronous motor, the total voltage setpoint is made to increase or decrease linearly with the current motor operating frequency according to the slope until the rated operating point is reached.

[0126] In some preferred embodiments, establishing a voltage closed-loop control circuit, comparing the total voltage setpoint with the amplitude of the actual motor output voltage and performing proportional-integral adjustment, and outputting it as a reactive current command value, includes:

[0127] Calculate the first deviation between the total voltage setpoint and the amplitude of the actual output voltage of the motor; input the first deviation to a preset first proportional-integral regulator for calculation; and use the output value of the first proportional-integral regulator as the reactive current command value.

[0128] In some preferred embodiments, establishing a reactive current closed-loop control circuit, comparing the reactive current command value with the reactive current feedback component and performing proportional-integral adjustment, and outputting a quadrature-axis voltage setpoint includes:

[0129] Calculate the second deviation between the reactive current command value and the reactive current feedback component; input the second deviation to a preset second proportional-integral regulator for calculation; and use the output value of the second proportional-integral regulator as the quadrature-axis voltage setpoint.

[0130] In some preferred embodiments, the synthesis of a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint includes:

[0131] Using the direct-axis voltage setpoint and the quadrature-axis voltage setpoint as rectangular coordinate components, calculate the magnitude of the voltage vector and its direction angle relative to the direct-axis voltage setpoint; add the direction angle to the voltage orientation angle to obtain the final phase angle of the voltage vector.

[0132] In some preferred embodiments, feeding back the amplitude of the voltage vector as the amplitude of the actual output voltage of the motor to the voltage closed-loop control loop includes:

[0133] In each pulse width modulation control cycle, the amplitude of the voltage vector is calculated and updated in real time based on the direct-axis voltage setpoint and quadrature-axis voltage setpoint obtained from the pulse width modulation control cycle. The updated amplitude of the voltage vector is used as the amplitude of the actual output voltage of the motor for voltage closed-loop regulation calculation in the next pulse width modulation control cycle.

[0134] It should be understood that in the embodiments of this application, the processor 502 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0135] It will be understood by those skilled in the art that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program may be stored in a storage medium, which is a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the process steps of the embodiments of the above methods.

[0136] Therefore, the present invention also provides a storage medium. This storage medium can be a computer-readable storage medium. The storage medium stores a computer program. When executed by a processor, the computer program causes the processor to perform the following steps:

[0137] The three-phase stator current of the asynchronous motor is detected to obtain the three-phase current sampling value;

[0138] The voltage orientation angle in the voltage synchronous rotating coordinate system is obtained by integrating the given frequency of the controller.

[0139] The voltage orientation angle is used to transform the three-phase current sampling values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, so as to obtain the active current feedback component and reactive current feedback component in the two-phase rotating coordinate system.

[0140] Based on the current motor operating frequency and the preset constant voltage-frequency ratio, a total voltage setpoint is generated;

[0141] A voltage closed-loop control circuit is established, the total voltage setpoint is compared with the amplitude of the actual output voltage of the motor and proportional-integral adjustment is performed, and the output is used as the reactive current command value.

[0142] Establish a reactive current closed-loop control circuit, compare the reactive current command value with the reactive current feedback component and adjust it proportionally and integrally, and output the quadrature axis voltage setpoint.

[0143] Subtracting the quadrature-axis voltage setpoint from the total voltage setpoint yields the direct-axis voltage setpoint.

[0144] Based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of the voltage vector is fed back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor.

[0145] In some preferred embodiments, the step of integrating the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system includes:

[0146] The given frequency is continuously integrated over time, and the resulting integrated angle is used as the voltage orientation angle.

[0147] In some preferred embodiments, generating the total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio includes:

[0148] The starting voltage and slope are set according to the rated parameters of the asynchronous motor. During the acceleration or deceleration of the asynchronous motor, the total voltage setpoint is made to increase or decrease linearly with the current motor operating frequency according to the slope until the rated operating point is reached.

[0149] In some preferred embodiments, establishing a voltage closed-loop control circuit, comparing the total voltage setpoint with the amplitude of the actual motor output voltage and performing proportional-integral adjustment, and outputting it as a reactive current command value, includes:

[0150] Calculate the first deviation between the total voltage setpoint and the amplitude of the actual output voltage of the motor; input the first deviation to a preset first proportional-integral regulator for calculation; and use the output value of the first proportional-integral regulator as the reactive current command value.

[0151] In some preferred embodiments, establishing a reactive current closed-loop control circuit, comparing the reactive current command value with the reactive current feedback component and performing proportional-integral adjustment, and outputting a quadrature-axis voltage setpoint includes:

[0152] Calculate the second deviation between the reactive current command value and the reactive current feedback component; input the second deviation to a preset second proportional-integral regulator for calculation; and use the output value of the second proportional-integral regulator as the quadrature-axis voltage setpoint.

[0153] In some preferred embodiments, the synthesis of a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint includes:

[0154] Using the direct-axis voltage setpoint and the quadrature-axis voltage setpoint as rectangular coordinate components, calculate the magnitude of the voltage vector and its direction angle relative to the direct-axis voltage setpoint; add the direction angle to the voltage orientation angle to obtain the final phase angle of the voltage vector.

[0155] In some preferred embodiments, feeding back the amplitude of the voltage vector as the amplitude of the actual output voltage of the motor to the voltage closed-loop control loop includes:

[0156] In each pulse width modulation control cycle, the amplitude of the voltage vector is calculated and updated in real time based on the direct-axis voltage setpoint and quadrature-axis voltage setpoint obtained from the pulse width modulation control cycle. The updated amplitude of the voltage vector is used as the amplitude of the actual output voltage of the motor for voltage closed-loop regulation calculation in the next pulse width modulation control cycle.

[0157] The storage medium is a physical, non-transient storage medium, such as a USB flash drive, external hard drive, read-only memory (ROM), magnetic disk, or optical disk, or any other physical storage medium capable of storing program code. The computer-readable storage medium can be non-volatile or volatile.

[0158] Those skilled in the art will 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 implementations should not be considered beyond the scope of this invention.

[0159] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of each unit is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0160] The steps in the method of this invention can be adjusted, merged, or reduced in order according to actual needs. The units in the device of this invention can be merged, divided, or reduced according to actual needs. Furthermore, the functional units in the various embodiments of this 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.

[0161] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or 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, a terminal, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0162] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0163] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Since these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

[0164] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A constant voltage-frequency ratio control method for an asynchronous motor, characterized in that, include: The three-phase stator current of the asynchronous motor is detected to obtain the three-phase current sampling value; the given frequency of the controller is integrated to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system; The voltage orientation angle is used to transform the three-phase current sampling values ​​from a three-phase stationary coordinate system to a two-phase rotating coordinate system with the voltage orientation angle as a reference, so as to obtain the active current feedback component and reactive current feedback component in the two-phase rotating coordinate system. Based on the current motor operating frequency and the preset constant voltage-frequency ratio, a total voltage setpoint is generated; A voltage closed-loop control circuit is established, the total voltage setpoint is compared with the amplitude of the actual output voltage of the motor and proportional-integral adjustment is performed, and the output is used as the reactive current command value. A reactive current closed-loop control circuit is established. The reactive current command value is compared with the reactive current feedback component and proportional-integral adjustment is performed to output the quadrature-axis voltage setpoint. The quadrature-axis voltage setpoint is subtracted from the total voltage setpoint to obtain the direct-axis voltage setpoint. Based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint, a voltage vector for space vector pulse width modulation is synthesized, and the amplitude of the voltage vector is fed back to the voltage closed-loop control loop as the amplitude of the actual output voltage of the motor.

2. The constant voltage-frequency ratio control method for an asynchronous motor according to claim 1, characterized in that, The step of integrating the given frequency of the controller to obtain the voltage orientation angle in the voltage synchronous rotating coordinate system includes: performing continuous-time integration on the given frequency and using the obtained integrated angle as the voltage orientation angle.

3. The constant voltage-frequency ratio control method for an asynchronous motor according to claim 1, characterized in that, The step of generating a total voltage setpoint based on the current motor operating frequency and a preset constant voltage-frequency ratio includes: setting an initial voltage and slope according to the rated parameters of the asynchronous motor; and during the acceleration or deceleration of the asynchronous motor, making the total voltage setpoint linearly increase or decrease with the current motor operating frequency according to the slope until the rated operating point is reached.

4. The constant voltage-frequency ratio control method for an asynchronous motor according to claim 1, characterized in that, The establishment of the voltage closed-loop control circuit, which compares the amplitude of the total voltage setpoint with the amplitude of the actual output voltage of the motor and performs proportional-integral adjustment, and outputs the result as the reactive current command value, includes: calculating a first deviation between the amplitude of the total voltage setpoint and the amplitude of the actual output voltage of the motor; inputting the first deviation to a preset first proportional-integral regulator for calculation; and using the output value of the first proportional-integral regulator as the reactive current command value.

5. The constant voltage-frequency ratio control method for an asynchronous motor according to claim 1, characterized in that, The process of establishing a reactive current closed-loop control circuit, comparing the reactive current command value with the reactive current feedback component, and performing proportional-integral adjustment to output a quadrature-axis voltage setpoint includes: calculating a second deviation between the reactive current command value and the reactive current feedback component; inputting the second deviation to a preset second proportional-integral regulator for calculation; and using the output value of the second proportional-integral regulator as the quadrature-axis voltage setpoint.

6. The constant voltage-frequency ratio control method for an asynchronous motor according to claim 1, characterized in that, The step of synthesizing a voltage vector for space vector pulse width modulation based on the direct-axis voltage setpoint and the quadrature-axis voltage setpoint includes: using the direct-axis voltage setpoint and the quadrature-axis voltage setpoint as rectangular coordinate components, calculating the magnitude of the voltage vector and its direction angle relative to the direct-axis voltage setpoint; and adding the direction angle to the voltage orientation angle to obtain the final phase angle of the voltage vector.

7. The constant voltage-frequency ratio control method for an asynchronous motor according to claim 6, characterized in that, The step of feeding back the amplitude of the voltage vector as the amplitude of the actual output voltage of the motor to the voltage closed-loop control loop includes: in each pulse width modulation control cycle, calculating and updating the amplitude of the voltage vector in real time based on the direct-axis voltage setpoint and quadrature-axis voltage setpoint calculated in the pulse width modulation control cycle, and using the updated amplitude of the voltage vector as the amplitude of the actual output voltage of the motor for voltage closed-loop adjustment calculation in the next pulse width modulation control cycle.

8. A constant voltage-frequency ratio control device for an asynchronous motor, characterized in that, Includes a unit for performing the method as described in any one of claims 1-7.

9. A computer device, characterized in that, The computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, can implement the method as described in any one of claims 1-7.

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