Induction motor control methods, devices, equipment, and storage media

Abstract

This application discloses an induction motor control method, apparatus, device, and storage medium. The method includes: determining an optimal starting frequency by acquiring the initial equivalent circuit parameters of the induction motor at zero speed, and determining the starting voltage by a preset starting current, so as to enable the induction motor to enter the starting operation stage. Subsequently, when it is determined that the starting speed of the induction motor in the starting operation stage accelerates to be consistent with the preset stable operating speed, the induction motor is determined to switch from the starting operation stage to the stable operation stage. In the stable operation stage, the stator, rotor, and excitation branch are identified online using voltage and current data. The induction motor is then driven to run according to the obtained optimal operating frequency, and the actual speed of the motor is monitored in real time so as to adjust the driving voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor. Thus, the operating efficiency and starting capability of the induction motor can be improved without increasing the cost of the frequency converter.

Description

[Technical Field]

[0001] This application relates to the field of induction motor control technology, and in particular to an induction motor control method, apparatus, device and storage medium. [Previous Technology]

[0002] Induction motors are widely used in many fields due to their advantages such as simple structure, high reliability, stable performance and simple drive controller control program.

[0003] Induction motors are typically operated under light loads significantly below their rated load to reduce operational risks. To improve the operating efficiency of induction motors under light loads, most existing motor control methods employ electronic frequency converters for variable frequency speed control. To ensure controller safety, the safety current capacity of the power semiconductors in the electronic frequency converter needs to be increased to enhance the current redundancy of the power semiconductors and thus improve the overload and starting capabilities of the induction motor. However, this increases the cost of the frequency converter.

[0004] Therefore, how to improve the operating efficiency and starting capability of induction motors without increasing the cost of power semiconductors in frequency converters has always been a key technical challenge that needs to be overcome in the field of induction motor applications. [Summary of the Invention]

[0005] The main objective of this application is to provide an induction motor control method, device, equipment, and storage medium, which aims to significantly improve the operating efficiency and optimize the starting capability of the induction motor without increasing the cost of the frequency converter.

[0006] To achieve the above objective, this application provides an induction motor control method. The induction motor control method is applied to a motor driver, the motor driver being electrically connected to an induction motor. The equivalent circuit of the induction motor includes a stator branch, a rotor branch, and an excitation branch. The induction motor control method includes: acquiring initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero; determining the optimal starting frequency of the induction motor based on the initial equivalent parameters; determining the starting voltage based on the optimal starting frequency and a preset safe starting current; enabling the induction motor to enter the start-up operation stage according to the optimal starting frequency and the starting voltage; acquiring the motor starting speed of the induction motor during the start-up operation stage; when the motor starting speed accelerates to match a preset stable operating speed, determining that the induction motor switches from the start-up operation stage to the stable operation stage; acquiring voltage and current data of the induction motor during the stable operation stage; performing online identification calculations on the stator branch, the rotor branch, and the excitation branch based on the voltage and current data; and determining the optimal operating frequency of the induction motor based on the identified parameters. The induction motor is driven to operate during the stable operation phase according to the optimal operating frequency, and the actual speed of the induction motor during the stable operation phase is obtained. The driving voltage is adjusted according to the actual speed of the motor to maintain the steady-state operation of the induction motor.

[0007] In one embodiment, the step of adjusting the drive voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor includes: obtaining updated equivalent parameters of the induction motor during steady-state operation and detecting whether the actual speed of the motor deviates from the stable operating speed; if the actual speed of the motor deviates from the stable operating speed, adjusting the drive voltage according to the updated equivalent parameters to maintain the steady-state operation of the induction motor; if the actual speed of the motor does not deviate from the stable operating speed, determining that the induction motor maintains steady-state operation.

[0008] In one embodiment, the step of obtaining the updated equivalent parameters of the induction motor during steady-state operation includes: fine-tuning the drive frequency of the induction motor during steady-state operation at the current fine-tuning moment to obtain the current fine-tuning frequency, and collecting the historical fine-tuning frequency obtained by fine-tuning the drive frequency of the induction motor during steady-state operation at the previous fine-tuning moment, and the future fine-tuning frequency obtained by fine-tuning the drive frequency of the induction motor during steady-state operation at the next fine-tuning moment; constructing a full-rank equivalent parameter simultaneous equation system based on the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency; and determining the updated equivalent parameters of the induction motor based on the full-rank equivalent parameter simultaneous equation system.

[0009] In one embodiment, the step of constructing a full-rank equivalent parameter simultaneous equation system based on the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency includes: obtaining the current driving voltage and current driving current of the induction motor at the current fine-tuning frequency, the historical driving voltage and historical driving current of the induction motor at the historical fine-tuning frequency, and the future driving voltage and future driving current of the induction motor at the future fine-tuning frequency; constructing a current equivalent parameter model based on the current fine-tuning frequency, the current driving voltage, and the current driving current; constructing a historical equivalent parameter model based on the historical fine-tuning frequency, the historical driving voltage, and the historical driving current; and constructing a future equivalent parameter model based on the future fine-tuning frequency, the future driving voltage, and the future driving current; and performing simultaneous equation processing based on the current equivalent parameter model, the historical equivalent parameter model, and the future equivalent parameter model to obtain a full-rank equivalent parameter simultaneous equation system.

[0010] In one embodiment, the step of determining the updated equivalent parameters of the induction motor based on the simultaneous equations of the full-rank equivalent parameters includes: performing online identification operations on the stator branch, the rotor branch, and the excitation branch respectively based on the simultaneous equations of the full-rank equivalent parameters to obtain the stator equivalent parameters, rotor equivalent parameters, and excitation equivalent parameters of the induction motor during steady-state operation; and using the stator equivalent parameters, the rotor equivalent parameters, and the excitation equivalent parameters as the updated equivalent parameters of the induction motor.

[0011] In one embodiment, the step of adjusting the drive voltage according to the updated equivalent parameters to maintain the steady-state operation of the induction motor includes: determining the optimal actual frequency of the induction motor at the stable operating speed according to the updated equivalent parameters; after driving the induction motor according to the optimal actual frequency, adjusting the drive voltage of the induction motor at the optimal actual frequency according to the speed difference between the actual speed of the motor and the stable operating speed, and maintaining the steady-state operation of the induction motor according to the adjusted drive voltage and the optimal actual frequency.

[0012] In one embodiment, the step of maintaining steady-state operation of the induction motor based on the adjusted drive voltage and the optimal actual frequency includes: driving the induction motor according to the adjusted drive voltage and the optimal actual frequency to obtain the current motor speed of the induction motor; taking the current motor speed as the next actual motor speed, returning to the step of detecting whether the actual motor speed deviates from the stable operating speed, and accumulating the number of return executions; until the actual motor speed is detected not to deviate from the stable operating speed within a preset return count threshold, then obtaining the optimal drive frequency and actual drive voltage of the induction motor at the actual motor speed, and driving the induction motor according to the optimal drive frequency and the actual drive voltage to maintain steady-state operation.

[0013] In addition, to achieve the above objectives, this application also provides an induction motor control device, the induction motor control device comprising: a start-up module, configured to acquire the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determine the optimal start-up frequency of the induction motor based on the initial equivalent parameters, determine the start-up voltage based on the optimal start-up frequency and a preset safe start-up current, and enable the induction motor to enter the start-up operation phase according to the optimal start-up frequency and the start-up voltage; a steady-state operation module, configured to acquire the motor start-up speed of the induction motor during the start-up operation phase, determine that the induction motor switches from the start-up operation phase to the steady-state operation phase when the motor start-up speed accelerates to be consistent with the preset steady-state operation speed, acquire the voltage and current data of the induction motor during the steady-state operation phase, perform online identification calculations on the stator branch, the rotor branch and the excitation branch based on the voltage and current data, and determine the optimal operating frequency of the induction motor based on the identified parameters; A steady-state maintenance module is used to drive the induction motor to operate during the stable operation phase according to the optimal operating frequency, and to obtain the actual speed of the induction motor when it is operating during the stable operation phase, and to adjust the drive voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor.

[0014] Each functional module of the induction motor control device of this application implements the steps of the induction motor control method of this application as described above during operation.

[0015] Each functional module of the induction motor control device of this application implements the steps of the induction motor control method of this application as described above during operation.

[0016] In addition, to achieve the above objectives, this application also provides an induction motor control device, which includes a memory, a processor, and a motor control program stored in the memory and executable on the processor. When the motor control program is executed by the processor, it implements the steps of the induction motor control method described above.

[0017] In addition, to achieve the above objectives, this application also provides a storage medium, which is a computer-readable storage medium, on which a motor control program is stored, and when the motor control program is executed by a processor, it implements the steps of the above-described induction motor control method.

[0018] This application provides an induction motor control method to significantly improve the operating efficiency and optimize the starting capability of the induction motor. Specifically, to improve the insufficient starting torque characteristic of the induction motor during operation, this application uses a motor driver to accurately obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero. Based on the optimal starting frequency obtained from these initial equivalent parameters, and combined with the starting voltage determined by the preset safe starting current, the induction motor is started smoothly and efficiently, thereby significantly improving its starting capability. Next, after starting the induction motor according to the optimal starting frequency and starting voltage for the start-up operation phase, the starting speed of the induction motor is detected in real time. When the starting speed accelerates to match the preset stable operating speed, it indicates that the induction motor has successfully transitioned from the start-up phase to the stable operating phase. Subsequently... The system acquires voltage and current data of the induction motor during its stable operation phase. Based on this data, it performs efficient online identification calculations on the stator branch, rotor branch, and excitation branch, respectively. The optimal operating frequency of the induction motor can be accurately determined based on the identified parameters. Next, the induction motor is driven to operate at this optimal operating frequency during the stable operation phase, ensuring high efficiency during steady-state operation. Subsequently, by real-time monitoring of the actual motor speed during the stable operation phase, the drive voltage is adjusted based on the actual motor speed to dynamically maintain the steady-state operation of the induction motor. This achieves a significant improvement in the operating efficiency and comprehensive optimization of the starting capability of the induction motor without increasing the cost of the frequency converter.

Implementation Method

[0020] This application provides an induction motor control method. Referring to FIG1, FIG1 is a flowchart of the first embodiment of the induction motor control method of this application.

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the drawings. In the following description, when referring to drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0022] Induction motors are widely used in many fields due to their simple structure, high reliability, stable performance, and simple control program for drive controllers. However, these motors have low starting torque. To reduce operational risks, many motors are routinely operated under light loads significantly below their rated load. The efficiency of induction motors under light loads is relatively low.

[0023] When speed control of an induction motor is required, an electronic frequency converter is typically used to drive the induction motor via frequency conversion. To address the problem of insufficient starting torque in induction motors, the current redundancy of the frequency converter must be large to increase the starting torque of the motor by increasing the starting current. This necessitates increasing the safe current capacity of the power semiconductors in the frequency converter, thereby increasing the cost of the frequency converter.

[0024] To address the above-mentioned deficiencies, this application provides an induction motor control method, apparatus, device, and storage medium.

[0025] The induction motor control method provided in this application can be applied to a motor driver electrically connected to an induction motor, or it can be executed by an induction motor control device that drives and controls the induction motor. Specifically, the induction motor control method described below is executed by the control center in the terminal device. Furthermore, the equivalent circuit of the induction motor includes a stator branch, a rotor branch, and an excitation branch; that is, the equivalent circuit provided in this application is a T-type equivalent circuit composed of the stator branch, the rotor branch, and the excitation branch. The executing entity of this application will not be described in detail in the following embodiments.

[0026] Furthermore, referring to Figure 2, which is a schematic diagram of the equivalent circuit of the induction motor involved in the embodiment of this application, the stator branch is electrically connected to the rotor branch and the excitation branch respectively, and the excitation branch is electrically connected to the rotor branch. The stator branch includes at least a resistor R1 and an inductor L1; the rotor branch includes at least a resistor R2 and an inductor L2; and the excitation branch includes at least a resistor Rm and an inductor Lm. Wherein, S in the rotor branch is the slip rate of the motor speed.

[0027] The induction motor control method of this application may include steps S10 to S30:

[0028] Step S10: Obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determine the optimal starting frequency of the induction motor based on the initial equivalent parameters, determine the starting voltage based on the optimal starting frequency and the preset safe starting current, and enable the induction motor to enter the starting operation stage according to the optimal starting frequency and the starting voltage.

[0029] In this embodiment, before starting the induction motor (i.e., before the induction motor enters the start-up phase), the motor driver provided in this application can accurately obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, thereby providing accurate and reliable data support for determining the optimal start-up frequency. Subsequently, based on the initial equivalent parameters, the optimal start-up frequency of the induction motor can be accurately obtained, and based on the optimal start-up frequency and the safe start-up current required by the induction motor (i.e., the preset safe start-up current), the start-up voltage is determined. Then, the induction motor is started according to the optimal start-up frequency and the start-up voltage, thereby enabling the induction motor to enter the start-up phase. This not only ensures the smoothness of the induction motor start-up process but also effectively shortens the start-up time of the induction motor and reduces the energy loss of the induction motor during the start-up phase, thereby effectively improving the start-up capability of the induction motor.

[0030] It should be noted that the initial equivalent parameters can be customized according to application requirements (i.e., pre-configured based on the human-computer interaction interface), or obtained through calculations by automatic parameter identification. The preset safe starting current is also customized according to application requirements, and this application does not impose any restrictions on it.

[0031] In a specific embodiment, if the initial equivalent parameters of the induction motor when the motor speed is zero are pre-configured based on the human-machine interface, that is, the initial equivalent parameters are preset, then the optimal starting frequency of the induction motor is determined according to the preset initial equivalent parameters and the preset starting frequency algorithm, and the starting voltage is calculated according to the optimal starting frequency and the starting current required by the induction motor; next, the induction motor is started according to the optimal starting frequency and the starting voltage to ensure that the induction motor enters the starting operation stage, thereby achieving a significant improvement in the starting performance and efficiency of the induction motor.

[0032] When the initial equivalent parameters of the induction motor at zero speed are obtained through online parameter identification, the voltage and current data of the induction motor during the start-up and operation phase are first acquired. The stator branch, rotor branch, and excitation branch are then processed online according to these voltage and current data to obtain the stator equivalent parameters, rotor equivalent parameters, and excitation equivalent parameters of the induction motor during the start-up and operation phase. These parameters are then used as the initial equivalent parameters of the induction motor during the start-up and operation phase. Next, the optimal start-up frequency of the induction motor is determined based on these initial equivalent parameters and a preset start-up frequency algorithm. The start-up voltage is then calculated based on this optimal start-up frequency and the required start-up current of the induction motor. Subsequently, the induction motor is started according to this optimal start-up frequency and start-up voltage to ensure that the induction motor can start with the most suitable start-up voltage and optimal start-up frequency during the start-up and operation phase, thereby avoiding problems such as motor overload, vibration, or damage caused by improper start-up parameter settings. Meanwhile, a reasonable starting voltage and optimal starting frequency can effectively reduce energy consumption and wear during induction motor startup, improve the service life of the induction motor, and enhance the dynamic response capability of the induction motor, enabling it to enter the stable operation stage more quickly, thereby improving the operating efficiency and stability of the induction motor.

[0033] It should be noted that the preset starting frequency algorithm includes formula (1) and formula (2), wherein formula (1) is as follows: (1) Wherein, is the motor speed of the induction motor, which means that the motor speed of the induction motor is zero; is the stator equivalent impedance of the induction motor during the start-up phase, and is the stator equivalent parameter of the induction motor during the start-up phase; is the angular frequency of the starting current required by the induction motor, and the starting current refers to the current value flowing through the stator branch when the motor speed is zero; is the rotor equivalent impedance of the induction motor during the start-up phase, and is the rotor equivalent parameter of the induction motor during the start-up phase; is the excitation equivalent impedance of the induction motor during the start-up phase, and is the excitation equivalent parameter of the induction motor during the start-up phase; is the imaginary unit, which is a fixed value that can be customized according to the user's needs; is the number of stator winding phases of the stator branch, and is the number of magnetic pole pairs of the induction motor; is the starting torque of the induction motor when the motor speed is zero, which is also called the motor electromagnetic torque of the induction motor during the start-up phase. In addition, R1 represents the resistance value of the stator branch during the start-up phase, and L1 represents the inductance value of the stator branch during the start-up phase; R2 represents the resistance value of the rotor branch during the start-up phase, and L2 represents the inductance value of the rotor branch during the start-up phase; Rm represents the resistance value of the excitation branch during the start-up phase, and Lm represents the inductance value of the excitation branch during the start-up phase; Rm represents the current flowing through the rotor branch when the motor speed is zero; and Lm represents the phasor of the rotor current, which refers to the equivalent impedance of the rotor branch and the excitation branch connected in parallel when the motor speed is zero.

[0034] Formula (2) is as follows: (2) Where, is the optimal starting frequency of the induction motor when the motor speed is zero. The optimal starting frequency obtained by formula (2) can be understood as the frequency at which the induction motor can generate the maximum "torque / current ratio" when the motor speed is zero; refers to the starting current of the induction motor in the first starting and running stage; refers to the motor speed of the induction motor being zero; is the starting torque of the induction motor when the motor speed is zero; is the current value flowing through the rotor branch of the induction motor when the motor speed is zero.

[0035] In another embodiment, referring to FIG3, FIG3 is a multi-stage start-up control flowchart involving the embodiment of the present application. The start-up operation stage can be divided into multiple operation stages, such as start-up operation "stage 1", start-up operation "stage 2", start-up operation "stage ..." and start-up operation "stage M", wherein each start-up operation "stage *" includes the starting speed of the motor and the final speed of the motor, and the final speed of each start-up operation stage is the starting speed of the next start-up operation stage. In addition, the final speed of the last start-up operation stage can be equal to the stable operating speed of the induction motor in the stable operation stage, or a value close to the stable operating speed. For example, in Figure 3, the starting speed of stage 1 is n=0 and the final speed is n=ns1, the starting speed of stage 2 is n=ns1 and the final speed is n=ns2, ..., the starting speed of stage M is n=ns(M-1) and the final speed is n=nsM; in addition, stage M refers to the last start-up operation stage, and the final speed nsM in stage M is the stable operating speed ne of the induction motor in the stable operation stage, or a value close to the stable operating speed ne.

[0036] For example, when the induction motor is adjusted from a state with a motor speed of n1, such as n1=0, to another state with a speed of n2, the optimal starting frequency and starting voltage V1 of the n1 state are adjusted to the optimal frequency and driving voltage V2 of the n2 state in a linear relationship within a set time T; and the time T is predetermined and input according to the rotational inertia and load of the system.

[0037] Step S20: Obtain the motor starting speed of the induction motor during the start-up operation phase. When the motor starting speed accelerates to match the preset stable operating speed, determine that the induction motor switches from the start-up operation phase to the stable operating phase. Obtain the voltage and current data of the induction motor during the stable operating phase. Perform online identification calculations on the stator branch, the rotor branch, and the excitation branch based on the voltage and current data. Determine the optimal operating frequency of the induction motor based on the identified parameters.

[0038] In this embodiment, after enabling the induction motor to enter the start-up phase with the start-up voltage determined according to the optimal start-up frequency and the required safe start-up current, the motor start-up speed of the induction motor during the start-up phase is collected at a preset speed collection frequency until the collected motor start-up speed accelerates to be equal to the stable operating speed ne of the induction motor during the stable operating phase, or is within the speed allowable error range corresponding to the stable operating speed ne (i.e., a value close to the stable operating speed ne). Then it is determined that the motor start-up speed has accelerated to be consistent with the preset stable operating speed, and thus it can be determined that the motor has efficiently and smoothly switched from the start-up phase to the stable operating phase. Next, the voltage and current data of the induction motor during the stable operating phase are obtained, and the stator branch, rotor branch and excitation branch are efficiently identified online based on the voltage and current data, thereby significantly improving the accuracy of parameter identification, and the optimal operating frequency of the induction motor can be accurately obtained based on the identified parameters.

[0039] It should be noted that voltage and current data can include voltage data and current data, wherein voltage data can characterize the operating current and current data can characterize the driving voltage.

[0040] In a specific embodiment, when it is determined that the motor starting speed accelerates to be consistent with the preset stable operating speed, the current value flowing through the stator branch of the induction motor when the motor starting speed is the stable operating speed ne, or close to the stable operating speed ne, is taken as the operating current. The optimal operating frequency is calculated based on the operating current and the preset optimal frequency calculation algorithm, and the driving voltage is calculated according to the optimal operating frequency and the operating current. Subsequently, the induction motor is driven to operate in steady state according to the optimal operating frequency and the driving voltage, which ensures that the induction motor maintains high efficiency during steady-state operation, thereby significantly improving the performance of the induction motor in the steady-state operation stage and ensuring the safe and efficient operation of the induction motor.

[0041] It should be noted that the stable operating speed of the induction motor during the stable operation phase is a fixed value, which can be customized according to application requirements.

[0042] The preset optimal frequency calculation algorithm includes formula (3) and formula (4), wherein formula (3) is as follows: (3) Wherein, refers to the motor speed of the induction motor as the final speed in stage M (i.e., the motor starting speed); refers to the current value flowing through the stator branch when the motor starting speed is the stable operating speed ne or close to the stable operating speed ne, i.e., the operating current; is the angular frequency of the operating current; refers to the rotor equivalent impedance of the induction motor in the starting and running stage, is the resistance value of the rotor branch resistor R2 in the starting and running stage; refers to the excitation equivalent impedance of the induction motor in the starting and running stage, is the number of stator winding phases of the stator branch, is the number of magnetic pole pairs of the induction motor; is the operating torque when the motor starting speed is the stable operating speed ne or close to the stable operating speed ne, is the phasor of the rotor current flowing through the rotor branch when the motor starting speed is the stable operating speed ne or close to the stable operating speed ne, is the slip rate of the rotor speed in the rotor branch when the motor starting speed is the stable operating speed ne or close to the stable operating speed ne.

[0043] Formula (4) is as follows: (4) Where, is the optimal operating frequency, which is the frequency at which the induction motor can generate the maximum "torque / current ratio" when the final speed of the induction motor in stage M is the stable operating speed ne or close to the stable operating speed ne; refers to the operating current of the induction motor in the last start-up operation stage (i.e., stage M); is the current value flowing through the rotor branch of the induction motor when the final speed is the stable operating speed ne or close to the stable operating speed ne.

[0044] Step S30: Drive the induction motor to run in the stable operation phase according to the optimal operating frequency, and obtain the actual speed of the induction motor when it is running in the stable operation phase. Adjust the driving voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor.

[0045] In this embodiment, after the induction motor is driven to run continuously in a steady state according to the optimal operating frequency and driving voltage, the actual speed of the induction motor during the steady-state operation is detected in real time. That is, by detecting the actual speed of the induction motor during steady-state operation in real time, the driving voltage of the induction motor is adjusted to dynamically maintain the steady-state operation of the induction motor. Thus, without increasing the cost of the frequency converter, the operating efficiency of the induction motor is significantly improved and the starting capability is fully optimized.

[0046] Further, in another embodiment, referring to FIG4, FIG4 is a block diagram of the control process involved in the embodiment of the present application. The induction motor control method provided in this application further includes steps 100 to 400.

[0047] Step 100: When the motor is starting up, calculate the optimal starting frequency based on the motor parameters at zero speed. Calculate the motor starting voltage Vso based on the motor parameters at this time and the required safe starting current. Start the motor using the optimal starting frequency and starting voltage Vso.

[0048] Step 200: When the motor starts up to the required stable operating speed ne, the optimal operating frequency at speed ne is calculated based on the motor parameters when the speed is zero. During the preset time T sr, the starting frequency is modulated linearly from to , while the drive voltage is adjusted from V so to the preset stable operating voltage V r.

[0049] Step 300: During steady-state operation at motor speed ne, the drive frequency is periodically fine-tuned multiple times. Each frequency adjustment involves sampling and analyzing the motor's drive voltage and drive current to establish and solve a system of simultaneous equations concerning the motor parameters. The optimal drive frequency fro (i.e., the optimal actual frequency) at the current speed is calculated using the obtained motor parameters.

[0050] Step 400: During steady-state operation at motor speed ne, the motor is driven using the optimal frequency fro. During steady-state operation, motor parameters are continuously calculated, motor speed is observed, and the current fro is calculated based on the new motor parameters. If the motor speed deviates from the required speed ne, the motor speed is adjusted by adjusting the drive voltage to ensure stable operation at ne.

[0051] In summary, this application provides an induction motor control method to significantly improve the operating efficiency and optimize the starting capability of the induction motor. Specifically, to improve the insufficient starting torque characteristic of the motor during operation, this application uses a motor driver to accurately obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero. Based on the optimal starting frequency obtained from these initial equivalent parameters, and combined with the starting voltage determined by the preset safe starting current, the induction motor is started smoothly and efficiently, thereby significantly improving its starting capability. Next, after starting the induction motor according to the optimal starting frequency and starting voltage for the start-up operation phase, the starting speed of the induction motor is detected in real time. When the starting speed accelerates to match the preset stable operating speed, it indicates that the induction motor has successfully transitioned from the start-up phase to the stable operating phase, and then obtains... Voltage and current data of the induction motor during its stable operation phase are collected. Based on this data, efficient online identification calculations are performed on the stator branch, rotor branch, and excitation branch. The optimal operating frequency of the induction motor can be accurately obtained based on the identified parameters. Next, the induction motor is driven to operate during the stable operation phase at the optimal operating frequency, thereby ensuring that the induction motor maintains high efficiency during steady-state operation. Subsequently, by real-time detection of the actual motor speed during the stable operation phase, the drive voltage is adjusted according to the actual motor speed to dynamically maintain the steady-state operation of the induction motor. Thus, without increasing the cost of the frequency converter, a significant improvement in the operating efficiency of the induction motor and a comprehensive optimization of its starting capability are achieved.

[0052] Further, based on the first embodiment of the induction motor control method of this application, a second embodiment of the induction motor control method of this application is proposed.

[0053] Further, in some feasible embodiments, the above step S30: adjusting the drive voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor, further includes the following implementation steps S301 to S303:

[0054] Step S301: Obtain the updated equivalent parameters of the induction motor during steady-state operation and detect whether the actual speed of the motor deviates from the stable operating speed.

[0055] In this embodiment, the updated equivalent parameters of the induction motor during steady-state operation are obtained and the actual speed of the motor is detected as deviating from the preset stable operating speed. The actual speed of the induction motor can be compared with the preset steady-state operating speed in real time. Once a deviation is detected, the adjustment mechanism is immediately triggered, such as adjusting the drive voltage, to ensure that the induction motor can quickly and accurately return to a stable operating state.

[0056] Step S302: If the actual speed of the motor deviates from the stable operating speed, adjust the drive voltage according to the updated equivalent parameters to maintain the steady-state operation of the induction motor.

[0057] In this embodiment, if the actual speed of the induction motor deviates from the stable operating speed during the steady-state operation phase, the driving voltage is adjusted according to the updated equivalent parameters, so that the actual speed of the induction motor returns to and is stably maintained at the preset stable operating speed, thereby maintaining the steady-state operation of the induction motor and ensuring the continuity and stability of the steady-state operation of the induction motor.

[0058] Step S303: If the actual speed of the motor does not deviate from the stable operating speed, then it is determined that the induction motor maintains steady-state operation.

[0059] In this embodiment, if the actual speed of the induction motor does not deviate from the stable operating speed during the steady-state operation phase, the induction motor will continue to be driven to maintain steady-state operation according to the optimal operating frequency and driving voltage.

[0060] Further, in some other feasible embodiments, the above step S302: obtaining the updated equivalent parameters of the induction motor during steady-state operation may also include the following implementation steps S3021 to S3023:

[0061] Step S3021: At the current fine-tuning moment, the driving frequency of the induction motor during steady-state operation is fine-tuned to obtain the current fine-tuning frequency. The historical fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor during steady-state operation at the previous fine-tuning moment is collected, as well as the future fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor during steady-state operation at the next fine-tuning moment is collected.

[0062] In this embodiment, after determining that the induction motor operates at a stable operating speed ne or close to the stable operating speed ne during steady-state operation, the drive frequency of the induction motor during steady-state operation is periodically fine-tuned multiple times to obtain multiple fine-tuning frequencies. This provides complete data support for subsequent sampling and analysis of the voltage and current during steady-state operation of the induction motor. Specifically, the drive frequency of the induction motor during steady-state operation is fine-tuned at the current moment to obtain the current fine-tuning frequency. Historical fine-tuning frequencies obtained from fine-tuning the drive frequency of the induction motor during steady-state operation at the previous fine-tuning moment are also collected, as well as future fine-tuning frequencies obtained from fine-tuning the drive frequency of the induction motor during steady-state operation at the next fine-tuning moment. This ensures the timeliness and continuity between multiple fine-tuning frequencies.

[0063] Further, in another embodiment, the historical fine-tuning frequency is (1-L)f, where f is the current fine-tuning frequency and L is a value in the range (0.01, 0.5); the future fine-tuning frequency is (1+H)f, where f is the current fine-tuning frequency and H is a value in the range (0.01, 0.5).

[0064] Step S3022: Construct a full-rank equivalent parameter simultaneous equation system based on the current fine-tuning frequency, the historical fine-tuning frequency and the future fine-tuning frequency.

[0065] In this embodiment, the current and voltage results obtained from the fine-tuning frequency data (i.e., the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency) collected at multiple consecutive fine-tuning moments are used to construct a full-rank equivalent parameter simultaneous equation system, thereby providing complete data for obtaining the updated equivalent parameters of the induction motor to form a full-rank equation system (i.e., a full-rank equivalent parameter simultaneous equation system).

[0066] Step S3023: Determine the updated equivalent parameters of the induction motor by solving the system of equations based on the full-rank equivalent parameters.

[0067] In this embodiment, by solving the system of simultaneous equations, the updated equivalent parameters of the induction motor can be accurately and quickly determined, thereby dynamically maintaining the steady-state operation of the induction motor based on the obtained updated equivalent parameters, ensuring that the induction motor can achieve optimal performance in actual operation.

[0068] Further, in some feasible embodiments, the above step S3022: constructing a full-rank equivalent parameter simultaneous equation system based on the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency, may also include the following implementation steps A10 to A30:

[0069] Step A10: Obtain the current driving voltage and current driving current of the induction motor at the current fine-tuning frequency, the historical driving voltage and historical driving current of the induction motor at the historical fine-tuning frequency, and the future driving voltage and future driving current of the induction motor at the future fine-tuning frequency.

[0070] In this embodiment, while using Discrete Fourier Analysis and a preset current calculation algorithm to calculate the current driving current of the induction motor at the current fine-tuning frequency, the historical driving current of the induction motor at the historical fine-tuning frequency, and the future driving current of the induction motor at the future fine-tuning frequency, Discrete Fourier Analysis and a preset voltage calculation algorithm are also used to calculate the current driving voltage of the induction motor at the current fine-tuning frequency, the historical driving voltage of the induction motor at the historical fine-tuning frequency, and the future driving voltage of the induction motor at the future fine-tuning frequency.

[0071] For example, taking the calculation of the current drive current under the current fine-tuning frequency as an example, the sine component and cosine component of the fundamental wave of the current drive current, as well as the phase angle of the current drive current, are calculated. The preset current calculation algorithm is shown in the following formula (5): (5) Where, is the fundamental wave of the current drive current under the current fine-tuning frequency, is the sine component of the current drive current, is the cosine component of the current fundamental wave, is the phase angle of the current drive current, is the sampling interval of the current drive current, is the sampling frequency of the current drive current, and is the current peak value reached by the induction motor in the steady-state operation phase when the sampling frequency is k.

[0072] In another embodiment, taking the calculation of the current driving current at the current fine-tuning frequency as an example, the sinusoidal component and cosine component of the fundamental wave of the current driving voltage, and the phase angle of the current driving current are calculated. The preset voltage calculation algorithm is shown in the following formula (6): (6) Where, is the sinusoidal voltage component of the fundamental wave of the current driving voltage, is the cosine component of the fundamental wave, is the voltage phase angle of the current driving voltage U1 shown in Figure 2, is the fundamental wave of the current driving voltage U1, is the sampling interval of the current driving voltage U1, and the sampling interval of the current driving voltage U1 is the same as the sampling interval of the current driving current; is the sampling frequency of the current driving voltage U1, and the sampling frequency of the current driving voltage U1 is the same as the sampling frequency of the current driving current, and is the voltage peak value reached when the induction motor is sampled at the kth sampling frequency during the steady-state operation phase.

[0073] Step A20: Construct a current equivalent parameter model based on the current fine-tuning frequency, the current driving voltage, and the current driving current; construct a historical equivalent parameter model based on the historical fine-tuning frequency, the historical driving voltage, and the historical driving current; and construct a future equivalent parameter model based on the future fine-tuning frequency, the future driving voltage, and the future driving current.

[0074] In this embodiment, the current equivalent parameter model can be accurately constructed based on the current fine-tuning frequency, the current driving voltage and the current driving current, the historical equivalent parameter model can be accurately constructed based on the historical fine-tuning frequency, the historical driving voltage and the historical driving current, and the future equivalent parameter model can be accurately constructed based on the future fine-tuning frequency, the future driving voltage and the future driving current.

[0075] It should be noted that the current equivalent parameter model is as shown in the following formula (7): (7) Where, refers to the current fine-tuning frequency; is the stator equivalent impedance of the stator branch at the current fine-tuning frequency, and is the stator equivalent parameter of the induction motor in the steady-state operation stage; is the rotor equivalent impedance of the rotor branch at the current fine-tuning frequency, and is the rotor equivalent parameter of the induction motor in the steady-state operation stage; is the excitation equivalent impedance of the excitation branch at the current fine-tuning frequency, and is the excitation equivalent parameter of the induction motor in the steady-state operation stage; is the phasor of the stator current (i.e., the current driving current) flowing through the stator branch at the current fine-tuning frequency, is the phasor of the stator voltage (i.e., the current driving voltage) acting on both ends of the stator branch at the current fine-tuning frequency, is the equivalent impedance of the rotor branch and the excitation branch in parallel at the current fine-tuning frequency, and is the slip rate of the rotor speed in the rotor branch at the current fine-tuning frequency.

[0076] It should be noted that the historical equivalent parameter model is as shown in the following formula (8):…………(8) Where, refers to the historical fine-tuning frequency; is the stator equivalent impedance of the stator branch at the historical fine-tuning frequency, and is the stator equivalent parameter of the induction motor in the steady-state operation stage; is the rotor equivalent impedance of the rotor branch at the historical fine-tuning frequency, and is the rotor equivalent parameter of the induction motor in the steady-state operation stage; is the excitation equivalent impedance of the excitation branch at the historical fine-tuning frequency, and is the excitation equivalent parameter of the induction motor in the steady-state operation stage; is the phasor of the stator current (i.e., the historical driving current) flowing through the stator branch at the historical fine-tuning frequency, is the phasor of the stator voltage (i.e., the historical driving voltage) acting on both ends of the stator branch at the historical fine-tuning frequency, and is the slip rate of the rotor speed in the rotor branch at the historical fine-tuning frequency.

[0077] The future equivalent parameter model is shown in the following formula (9): (9) Where, refers to the future fine-tuning frequency, is the stator equivalent impedance of the stator branch at the future fine-tuning frequency, and is the stator equivalent parameter of the induction motor in the steady-state operation stage; is the rotor equivalent impedance of the rotor branch at the future fine-tuning frequency, and is the rotor equivalent parameter of the induction motor in the steady-state operation stage; is the excitation equivalent impedance of the excitation branch at the future fine-tuning frequency, and is the excitation equivalent parameter of the induction motor in the steady-state operation stage; is the phasor of the stator current (i.e. the future drive current) flowing through the stator branch at the future fine-tuning frequency, is the phasor of the stator voltage (i.e. the future drive voltage) acting on both ends of the stator branch at the future fine-tuning frequency, and is the slip rate of the rotor speed in the rotor branch at the future fine-tuning frequency.

[0078] Step A30: Perform simultaneous equation processing based on the current equivalent parameter model, the historical equivalent parameter model and the future equivalent parameter model to obtain a full-rank system of equivalent parameter equations.

[0079] In this embodiment, the model is combined based on the historical equivalent parameter model and the future equivalent parameter model to obtain a full-rank equivalent parameter equation system composed of formulas (7) to (9), so that the updated equivalent parameters of the induction motor under the current condition can be solved.

[0080] Further, in some feasible embodiments, the above step S3023: determining the updated equivalent parameters of the induction motor by solving the simultaneous equations based on the full-rank equivalent parameters may also include the following implementation steps B10 to B20:

[0081] Step B10: Based on the full-rank equivalent parameters, perform online identification calculations on the stator branch, the rotor branch and the excitation branch respectively by solving the simultaneous equations to obtain the stator equivalent parameters, rotor equivalent parameters and excitation equivalent parameters of the induction motor in the steady-state operation stage.

[0082] Step B20: Use the stator equivalent parameters, the rotor equivalent parameters, and the excitation equivalent parameters as the updated equivalent parameters of the induction motor.

[0083] In this embodiment, after determining the full-rank equivalent parameter simultaneous equation system, the error of solving the nonlinear equation is accumulated, and it is detected whether the error is greater than a preset error threshold. If the error is less than or equal to the preset error threshold, the online parameter identification operation of the stator branch, rotor branch and excitation branch by the full-rank equivalent parameter simultaneous equation system composed of formulas (7) to (9) is completed. The stator equivalent parameters, rotor equivalent parameters and excitation equivalent parameters of the excitation branch in the steady-state operation stage can be accurately obtained. The stator equivalent parameters, rotor equivalent parameters and excitation equivalent parameters are used as the updated equivalent parameters of the induction motor. This process not only ensures the accuracy of parameter identification processing, but also improves the response speed of parameter identification processing, ensuring that the induction motor can achieve the optimal performance state in actual operation.

[0084] In another embodiment, if the number of iterations of the nonlinear equation is greater than a preset iteration threshold, then the solution obtained is the solution to the system of equations. This processing can improve the adaptability and robustness of online identification, and can adjust the strategy in a timely manner when data is abnormal or the model is mismatched, ensuring the stability and accuracy of the entire online identification operation process.

[0085] It should be noted that when the induction motor is in a stable operating phase, if other parameters need to be identified, such as the motor speed, more operating states need to be added to establish equations and solve them. If only some parameters that are sensitive to the environment and operating state are identified, the parameter identification and calculation can be simplified. For example, if only the identification of and , and is considered, the equivalent parameters of the stator branch and the equivalent parameters of the rotor branch can be calculated by using the current fine-tuning frequency and the historical fine-tuning frequency to solve the simultaneous equations established by formulas (7) and (8).

[0086] In addition, when the induction motor is in a stable operating phase, since the equivalent impedance of the induction motor is related to the motor's drive voltage, drive current, load characteristics and environment, in order to achieve accurate control of the induction motor, the online identification operation should be performed frequently as long as the computing speed of the controller's MCU (Micro Controller Unit) allows.

[0087] Further, in some other feasible embodiments, the above step S302: maintaining the steady-state operation of the induction motor according to the updated equivalent parameters may also include the following implementation steps C10 to C20:

[0088] Step C10: Based on the updated equivalent parameters, the optimal actual frequency of the induction motor under the stable operating speed can be accurately obtained.

[0089] In this embodiment, based on the updated equivalent parameters and the preset optimal frequency calculation algorithm, the optimal actual frequency of the induction motor under stable operating speed can be accurately obtained.

[0090] It should be noted that the updated equivalent parameters include at least the stator equivalent parameters, rotor equivalent parameters, and excitation equivalent parameters of the induction motor during the steady-state operation phase.

[0091] The preset optimal frequency calculation algorithm includes at least formula (10) and formula (11), wherein formula (10) is as follows: ... (10) Wherein, represents the stable operating speed of the induction motor; represents the stator equivalent impedance of the stator branch at the stable operating speed; represents the stator equivalent parameters of the induction motor during steady-state operation; represents the equivalent impedance of the rotor branch at the stable operating speed; represents the rotor equivalent parameters of the induction motor during steady-state operation; represents the excitation equivalent impedance of the excitation branch at the stable operating speed; represents the excitation equivalent parameters of the induction motor during steady-state operation; represents the imaginary unit; represents the angular frequency of the stator current in the stator branch at the stable operating speed, and the stator current at this time refers to the unit current flowing through the stator branch of the induction motor at the stable operating speed; represents the number of stator winding phases of the stator branch; represents the number of pole pairs of the induction motor; represents the electromagnetic torque of the induction motor at the stable operating speed; represents the current value of the rotor branch at the stable operating speed; represents the phasor of the rotor current, which refers to the equivalent impedance of the rotor branch and the excitation branch connected in parallel when the motor speed is at the stable operating speed.

[0092] Formula (11) is as follows: (11) Where, is the optimal actual frequency of the induction motor, is the unit current flowing through the rotor branch when the motor speed of the induction motor is the stable operating speed ne, refers to the speed of the induction motor being the stable operating speed ne, and is the current value of the rotor branch at the stable operating speed.

[0093] In addition, it should be noted that the calculation algorithm used to calculate the adjusted drive voltage is as shown in the following formula (12): (12) Where, is the adjusted drive voltage; is the preset adjustment voltage ratio increment, which can be customized according to application requirements, and this application does not impose any restrictions here; is the actual speed of the motor; is the stable operating speed; is the drive voltage.

[0094] Step C20: After driving the induction motor according to the optimal actual frequency, the driving voltage of the induction motor at the optimal actual frequency is adjusted according to the speed difference between the actual speed of the motor and the stable operating speed, and the steady-state operation of the induction motor is maintained according to the adjusted driving voltage and the optimal actual frequency.

[0095] In this embodiment, after driving the induction motor at the optimal actual frequency, the driving voltage of the induction motor at the optimal actual frequency is adjusted according to the speed difference between the actual speed of the motor and the stable operating speed until the actual speed of the motor is adjusted to be consistent with the preset stable operating speed, and the adjusted driving voltage is obtained. Next, the steady-state operation of the induction motor is dynamically maintained according to the adjusted driving voltage and the optimal actual frequency, so that the induction motor is always at the optimal efficiency point during the stable operation phase, thereby significantly improving the stability and energy efficiency of the induction motor operation without increasing the cost of the frequency converter.

[0096] Further, in some feasible embodiments, step C20: maintaining the steady-state operation of the induction motor based on the adjusted drive voltage and the optimal actual frequency may further include the following implementation steps C201 to C203:

[0097] Step C201: Drive the induction motor to run according to the optimal actual frequency and the adjusted drive voltage to obtain the current motor speed of the induction motor;

[0098] Step C202: Take the current speed of the motor as the next actual speed of the motor, return to the step of detecting whether the actual speed of the motor deviates from the stable operating speed, and return the cumulative number of executions.

[0099] In this embodiment, the induction motor is driven according to the optimal actual frequency and the adjusted driving voltage, so that the current speed of the induction motor can be accurately obtained. The current speed of the motor is then used as the next actual speed of the motor, and the step of detecting whether the actual speed of the motor deviates from the stable operating speed is returned to be executed. This helps to stabilize the operation of the induction motor.

[0100] Step C203: Until the actual speed of the motor is detected to be within the preset return number threshold and does not deviate from the stable operating speed, the optimal driving frequency and actual driving voltage of the induction motor at the actual motor speed are obtained, and the induction motor is driven to maintain steady-state operation according to the optimal driving frequency and the actual driving voltage.

[0101] In this embodiment, when the actual speed of the motor is detected to be within the preset return number threshold and does not deviate from the stable operating speed, the optimal driving frequency and actual driving voltage of the induction motor at the actual motor speed can be automatically obtained. As the induction motor is driven according to the optimal driving frequency and actual driving voltage to maintain steady-state operation, the induction motor can be continuously operated in a highly efficient and stable state, which significantly improves the reliability and energy efficiency of motor operation.

[0102] In summary, once the motor enters the steady-state operation phase, unlike the frequency conversion control of traditional induction motors, the induction motor driver of this application determines its driving frequency and driving voltage based on the load, the real-time parameters of the motor, and the required motor speed. During motor startup, the required "allowable starting current" can generate a larger starting torque; during steady-state operation, the copper losses of the motor can be minimized. Therefore, this invention can reduce the cost of the induction motor drive controller and improve motor efficiency. These effects are of positive significance for the application of induction motors.

[0103] In addition, this application also provides an induction motor control device. Please refer to FIG5, which is a schematic diagram of the structure of the induction motor control device involved in the embodiment of this application.

[0104] The induction motor control device of this application includes:

[0105] Starting module H01 is used to obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determine the optimal starting frequency of the induction motor based on the initial equivalent parameters, determine the starting voltage based on the optimal starting frequency and the preset safe starting current, and enable the induction motor to enter the starting operation stage according to the optimal starting frequency and the starting voltage.

[0106] The steady-state operation module H02 is used to obtain the motor starting speed of the induction motor during the start-up operation phase. When the motor starting speed accelerates to be consistent with the preset steady-state operation speed, it is determined that the induction motor switches from the start-up operation phase to the steady-state operation phase. The module also obtains the voltage and current data of the induction motor during the steady-state operation phase, performs online identification calculations on the stator branch, the rotor branch and the excitation branch based on the voltage and current data, and determines the optimal operating frequency of the induction motor based on the identified parameters.

[0107] The steady-state maintenance module H03 is used to drive the induction motor to operate in the stable operation phase according to the optimal operating frequency, and to obtain the actual speed of the induction motor when it is operating in the stable operation phase, and to adjust the drive voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor.

[0108] Each functional module of the induction motor control device of this application implements the steps of the induction motor control method of this application as described above during operation.

[0109] In addition, this application also provides an induction motor control device. Please refer to Figure 6, which is a schematic diagram of the structure of the induction motor control device involved in the embodiment of this application. Specifically, the induction motor control device in this embodiment can be a device for locally running an induction motor control method.

[0110] As shown in Figure 6, the induction motor control device of this application embodiment may include: a processor 1001, such as a CPU (Central Processing Unit), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to realize communication between these components. The user interface 1003 may include a display screen and an input unit such as a keyboard. Optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0111] The memory 1005 is disposed on the main body of the induction motor control device. The memory 1005 stores a program that performs corresponding operations when executed by the processor 1001. The memory 1005 is also used to store parameters used by the induction motor control device. The memory 1005 can be a high-speed RAM (random-access memory) or a stable memory (non-volatile memory), such as a disk storage device. Optionally, the memory 1005 can also be a storage device independent of the aforementioned processor 1001.

[0112] Those skilled in the art will understand that the structure of the induction motor control device shown in FIG6 does not constitute a limitation on the induction motor control device, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0113] As shown in Figure 6, the memory 1005, which serves as a storage medium, may include an operating system, a network communication module, a user interface module, and a motor control program for an induction motor control device.

[0114] In the induction motor control device shown in FIG6, the processor 1001 can be used to call the motor control program of the induction motor control device stored in the memory 1005 and execute the steps of any of the above induction motor control methods.

[0115] Furthermore, this application provides a storage medium that is a computer-readable storage medium. The computer-readable storage medium stores a motor control program, which, when executed by a processor, implements the steps of the aforementioned induction motor control method.

[0116] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0117] The sequence numbers of the above embodiments are for description only and do not represent the superiority or inferiority of the embodiments.

[0118] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a computer-readable storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause an induction motor control device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0119] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application. [Simplified Explanation of the Diagram]

[0019] Figure 1 is a flowchart of the first embodiment of the induction motor control method of this application; Figure 2 is a schematic diagram of the equivalent circuit of the induction motor involved in the embodiment of this application; Figure 3 is a flowchart of the multi-stage start-up control involved in the embodiment of this application; Figure 4 is a block diagram of the control process involved in the embodiment of this application; Figure 5 is a schematic diagram of the structure of the induction motor control device involved in the embodiment of this application; Figure 6 is a schematic diagram of the structure of the induction motor control equipment involved in the embodiment of this application.

Claims

1. An induction motor control method, wherein the induction motor control method is applied to a motor driver, the motor driver being electrically connected to an induction motor, and the equivalent circuit of the induction motor including a stator branch, a rotor branch, and an excitation branch; the induction motor control method includes: The process involves: acquiring the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero; determining the optimal starting frequency of the induction motor based on the initial equivalent parameters; determining the starting voltage based on the optimal starting frequency and a preset safe starting current; enabling the induction motor to enter the start-up operation phase according to the optimal starting frequency and the starting voltage; acquiring the motor starting speed of the induction motor during the start-up operation phase; determining that the induction motor switches from the start-up operation phase to the stable operation phase when the motor starting speed accelerates to match the preset stable operation speed; acquiring the voltage and current data of the induction motor during the stable operation phase; performing online identification calculations on the stator branch, the rotor branch, and the excitation branch based on the voltage and current data; determining the optimal operating frequency of the induction motor based on the identified parameters; driving the induction motor to operate during the stable operation phase according to the optimal operating frequency; acquiring the actual motor speed of the induction motor during the stable operation phase; and adjusting the drive voltage based on the actual motor speed to maintain the steady-state operation of the induction motor.

2. The induction motor control method as described in claim 1, wherein, The step of adjusting the drive voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor includes: obtaining updated equivalent parameters of the induction motor during steady-state operation and detecting whether the actual speed of the motor deviates from the stable operating speed; if the actual speed of the motor deviates from the stable operating speed, adjusting the drive voltage according to the updated equivalent parameters to maintain the steady-state operation of the induction motor; if the actual speed of the motor does not deviate from the stable operating speed, determining that the induction motor maintains steady-state operation.

3. The induction motor control method as described in claim 2, wherein, The step of obtaining the updated equivalent parameters of the induction motor during steady-state operation includes: fine-tuning the drive frequency of the induction motor during steady-state operation at the current fine-tuning moment to obtain the current fine-tuning frequency; collecting the historical fine-tuning frequency obtained by fine-tuning the drive frequency of the induction motor during steady-state operation at the previous fine-tuning moment; and collecting the future fine-tuning frequency obtained by fine-tuning the drive frequency of the induction motor during steady-state operation at the next fine-tuning moment; constructing a full-rank system of equivalent parameter equations based on the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency; and determining the updated equivalent parameters of the induction motor based on the full-rank system of equivalent parameter equations.

4. The induction motor control method as described in claim 3, wherein, The step of constructing a full-rank equivalent parameter simultaneous equation system based on the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency includes: obtaining the current driving voltage and current of the induction motor at the current fine-tuning frequency, the historical driving voltage and current of the induction motor at the historical fine-tuning frequency, and the future driving voltage and current of the induction motor at the future fine-tuning frequency; constructing a current equivalent parameter model based on the current fine-tuning frequency, the current driving voltage, and the current driving current; constructing a historical equivalent parameter model based on the historical fine-tuning frequency, the historical driving voltage, and the historical driving current; and constructing a future equivalent parameter model based on the future fine-tuning frequency, the future driving voltage, and the future driving current; and performing simultaneous equation processing based on the current equivalent parameter model, the historical equivalent parameter model, and the future equivalent parameter model to obtain the full-rank equivalent parameter simultaneous equation system.

5. The induction motor control method as described in claim 3, wherein, The step of determining the updated equivalent parameters of the induction motor based on the simultaneous equations of the full-rank equivalent parameters includes: performing online identification operations on the stator branch, the rotor branch, and the excitation branch respectively based on the simultaneous equations of the full-rank equivalent parameters to obtain the stator equivalent parameters, rotor equivalent parameters, and excitation equivalent parameters of the induction motor during steady-state operation; and using the stator equivalent parameters, rotor equivalent parameters, and excitation equivalent parameters as the updated equivalent parameters of the induction motor.

6. The induction motor control method as described in claim 2, wherein, The step of adjusting the drive voltage according to the updated equivalent parameters to maintain the steady-state operation of the induction motor includes: determining the optimal actual frequency of the induction motor at the stable operating speed according to the updated equivalent parameters; after driving the induction motor according to the optimal actual frequency, adjusting the drive voltage of the induction motor at the optimal actual frequency according to the speed difference between the actual speed of the motor and the stable operating speed, and maintaining the steady-state operation of the induction motor according to the adjusted drive voltage and the optimal actual frequency.

7. The induction motor control method as described in claim 6, wherein, The steps for maintaining steady-state operation of the induction motor based on the adjusted drive voltage and the optimal actual frequency include: driving the induction motor according to the adjusted drive voltage and the optimal actual frequency to obtain the current motor speed; using the current motor speed as the next actual motor speed, returning to the step of detecting whether the actual motor speed deviates from the stable operating speed, and accumulating the number of return executions; until the actual motor speed is detected not to deviate from the stable operating speed within a preset return count threshold, then obtaining the optimal drive frequency and actual drive voltage of the induction motor at the actual motor speed, and driving the induction motor according to the optimal drive frequency and the actual drive voltage to maintain steady-state operation.

8. An induction motor control device, comprising: The system comprises the following modules: a start-up module, which acquires the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determines the optimal start-up frequency of the induction motor based on the initial equivalent parameters, determines the start-up voltage based on the optimal start-up frequency and a preset safe start-up current, and enables the induction motor to enter the start-up operation phase according to the optimal start-up frequency and the start-up voltage; a steady-state operation module, which acquires the motor start-up speed of the induction motor during the start-up operation phase, determines that the induction motor switches from the start-up operation phase to the steady-state operation phase when the motor start-up speed accelerates to match the preset steady-state operation speed, acquires the voltage and current data of the induction motor during the steady-state operation phase, performs online identification calculations on the stator branch, rotor branch, and excitation branch based on the voltage and current data, and determines the optimal operating frequency of the induction motor based on the identified parameters; and a steady-state maintenance module, which drives the induction motor to operate during the steady-state operation phase according to the optimal operating frequency, acquires the actual motor speed of the induction motor during the steady-state operation phase, and adjusts the drive voltage according to the actual motor speed to maintain the steady-state operation of the induction motor.

9. An induction motor control device, comprising: A memory, a processor, and a motor control program stored in the memory and executable on the processor, wherein the processor, when executing the motor control program, implements the steps of the induction motor control method as described in any one of claims 1 to 7.

10. A storage medium, comprising: The storage medium is a computer-readable storage medium storing a motor control program, which, when executed by a processor, implements the steps of the induction motor control method as described in any one of claims 1 to 7.

Images