Induction motor control method and device, equipment and storage medium

Abstract

The invention discloses an induction motor control method and device, equipment and a storage medium, and the method comprises the steps: determining a good starting frequency through obtaining an initial equivalent circuit parameter at the zero speed of an induction motor, and determining a starting voltage through a preset starting current, so as to enable the induction motor to enter a starting operation stage, then, when it is determined that the motor starting rotation speed of the induction motor in the starting operation stage is accelerated to be consistent with the preset stable operation rotation speed, it is determined that the induction motor is switched to the stable operation stage from the starting operation stage, and parameter identification is conducted on a stator, a rotor and an excitation branch circuit through voltage and current data in the stable operation stage; and the induction motor is driven to operate according to the obtained good operation frequency, and the actual rotation speed of the motor is monitored in real time, so that the driving voltage is adjusted according to the actual rotation speed of the motor to maintain the steady-state operation of the induction motor, and the operation efficiency and the starting capability of the induction motor can be improved on the premise of not increasing the cost of a frequency converter.

Description

Technical Field

[0001] The present application relates to the technical field of induction motor control, and in particular to an induction motor control method, device, equipment and storage medium. Background Art

[0002] Induction motors are widely used in many fields due to their simple structure, good reliability, stable performance and simple drive controller control procedures.

[0003] Induction motors are usually operated at light loads significantly lower than their rated loads to reduce the risk of their operation. In order to improve the operating efficiency of induction motors when they are running at light loads, most existing motor control methods use electronic inverters to perform variable frequency speed control on induction motors. In order to ensure the safety of the controller, it is necessary to increase the safe current capacity of the power semiconductors in the electronic inverter to improve the current redundancy of the power semiconductors to enhance the overload capacity and starting capacity of the induction motor, but this also increases the cost of the inverter.

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

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

[0006] To achieve the above object, the present application provides an induction motor control method, the induction motor control method is applied to a motor driver, the motor driver is electrically connected to the induction motor, and the equivalent circuit of the induction motor includes a stator branch, a rotor branch and an excitation branch;

[0007] The induction motor control method comprises:

[0008] Acquire initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determine an optimal starting frequency of the induction motor according to the initial equivalent parameters, determine a starting voltage according to the optimal starting frequency and a preset safe starting current, and enable the induction motor to enter a starting operation phase according to the optimal starting frequency and the starting voltage;

[0009] Acquire the motor starting speed of the induction motor in the starting operation stage, and when the motor starting speed is accelerated to be consistent with the preset stable operation speed, determine that the induction motor switches from the starting operation stage to the stable operation stage, and acquire the voltage and current data of the induction motor in the stable operation stage, perform parameter identification on the stator branch, the rotor branch and the excitation branch respectively according to the voltage and current data, and determine the optimal operating frequency of the induction motor according to the identified parameters;

[0010] The induction motor is driven to operate in the stable operation stage according to the optimal operating frequency, and the actual motor speed of the induction motor when operating in the stable operation stage is obtained, and the driving voltage is adjusted according to the actual motor speed to maintain the steady-state operation of the induction motor.

[0011] In one embodiment, the step of adjusting the driving voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor includes:

[0012] Acquire 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;

[0013] If the actual speed of the motor deviates from the stable operating speed, adjusting the driving voltage according to the updated equivalent parameter to maintain the steady-state operation of the induction motor;

[0014] If the actual speed of the motor does not deviate from the stable operation speed, it is determined that the induction motor maintains steady-state operation.

[0015] In one embodiment, the step of obtaining updated equivalent parameters of the induction motor during steady-state operation includes:

[0016] Fine-tune the driving frequency of the induction motor when it is running in a steady state at a current fine-tuning moment to obtain a current fine-tuning frequency, collect a historical fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor when it is running in a steady state at a fine-tuning moment before the current fine-tuning moment, and collect a future fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor when it is running in a steady state at a fine-tuning moment next to the current fine-tuning moment;

[0017] Constructing a full-rank set of simultaneous equations of equivalent parameters according to the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency;

[0018] The updated equivalent parameters of the induction motor are determined according to the full-rank simultaneous equations of equivalent parameters.

[0019] In one embodiment, the step of constructing a full-rank set of simultaneous equations of equivalent parameters according to the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency includes:

[0020] Respectively acquiring a current driving voltage and a current driving current of the induction motor at the current fine-tuning frequency, a historical driving voltage and a historical driving current of the induction motor at the historical fine-tuning frequency, and a future driving voltage and a future driving current of the induction motor at the future fine-tuning frequency;

[0021] Constructing a current equivalent parameter model according to the current fine-tuning frequency, the current driving voltage, and the current driving current, constructing a historical equivalent parameter model according to the historical fine-tuning frequency, the historical driving voltage, and the historical driving current, and constructing a future equivalent parameter model according to the future fine-tuning frequency, the future driving voltage, and the future driving current;

[0022] Model simultaneous processing is performed according to 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 group.

[0023] In one embodiment, the step of determining updated equivalent parameters of the induction motor according to the full-rank set of simultaneous equations of equivalent parameters comprises:

[0024] According to the full-rank equivalent parameter simultaneous equations, parameter identification processing is performed on the stator branch, the rotor branch and the excitation branch respectively to obtain the stator equivalent parameters, the rotor equivalent parameters and the excitation equivalent parameters of the induction motor in the steady-state operation stage;

[0025] The stator equivalent parameter, the rotor equivalent parameter and the excitation equivalent parameter are used as updated equivalent parameters of the induction motor.

[0026] In one embodiment, the step of adjusting the driving voltage according to the updated equivalent parameter to maintain the steady-state operation of the induction motor includes:

[0027] Determining the optimal actual frequency of the induction motor at the stable operating speed according to the updated equivalent parameter;

[0028] 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.

[0029] In one embodiment, the step of maintaining the steady-state operation of the induction motor according to the adjusted driving voltage and the optimal actual frequency comprises:

[0030] Driving the induction motor to operate according to the adjusted driving voltage and the optimal actual frequency to obtain a current motor speed of the induction motor;

[0031] Taking the current speed of the motor as the next actual speed of the motor, returning to execute the step of detecting whether the actual speed of the motor deviates from the stable operating speed, and accumulating the number of executions returned;

[0032] Until it is detected within a preset return number threshold that the actual speed of the motor does not deviate from the stable operating speed, the optimal driving frequency and actual driving voltage of the induction motor at the actual speed of the motor are obtained, and the induction motor is driven according to the optimal driving frequency and the actual driving voltage to maintain steady-state operation.

[0033] In addition, to achieve the above-mentioned purpose, the present application also provides an induction motor control device, the induction motor control device comprising:

[0034] A starting module, used for obtaining initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determining an optimal starting frequency of the induction motor according to the initial equivalent parameters, and determining a starting voltage according to the optimal starting frequency and a preset safe starting current, and enabling the induction motor to enter a starting operation phase according to the optimal starting frequency and the starting voltage;

[0035] A steady-state operation module, used to obtain the motor starting speed of the induction motor in the starting operation stage, and when the motor starting speed is accelerated to be consistent with a preset stable operation speed, it is determined that the induction motor switches from the starting operation stage to the stable operation stage, and the voltage and current data of the induction motor in the stable operation stage are obtained, and the parameters of the stator branch, the rotor branch and the excitation branch are respectively identified according to the voltage and current data, and the optimal operating frequency of the induction motor is determined according to the identified parameters;

[0036] The steady-state maintaining module is used to drive the induction motor to operate in the steady-state operation stage according to the optimal operating frequency, obtain the actual motor speed of the induction motor when it operates in the steady-state operation stage, and adjust the driving voltage according to the actual motor speed to maintain the steady-state operation of the induction motor.

[0037] Each functional module of the induction motor control device of the present application implements the steps of the induction motor control method of the present application as described above during operation.

[0038] Each functional module of the induction motor control device of the present application implements the steps of the induction motor control method of the present application as described above during operation.

[0039] In addition, to achieve the above-mentioned purpose, the present 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, and the motor control program implements the steps of the above-mentioned induction motor control method when executed by the processor.

[0040] In addition, to achieve the above-mentioned purpose, the present application also provides a storage medium, which is a computer-readable storage medium, and a motor control program is stored on the computer-readable storage medium. When the motor control program is executed by the processor, the steps of the above-mentioned induction motor control method are implemented.

[0041] The present application provides an induction motor control method to achieve significant improvement in the operating efficiency of the induction motor and optimization of the starting capability. Specifically, in order to improve the characteristic of insufficient starting torque during the operation of the induction motor, the present application provides a motor driver that can accurately obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, and achieve smooth and efficient starting of the induction motor based on the optimal starting frequency obtained from the initial equivalent parameters, and the starting voltage determined in combination with the preset safe starting current, thereby significantly improving the starting capability of the induction motor; next, after starting the induction motor according to the optimal starting frequency and starting voltage to start the operation phase, the motor starting speed of the induction motor is detected in real time. When the motor starting speed is accelerated to be consistent with the preset stable operating speed, it indicates that the induction motor has successfully transitioned from the starting phase to the stable operation phase, and then Then, the voltage and current data of the induction motor in the stable operation stage are obtained, and the parameters of the stator branch, the rotor branch and the excitation branch are efficiently identified according to the voltage and current data, and the optimal operating frequency of the induction motor can be accurately obtained according to the identified parameters; next, the induction motor is driven to operate in the stable operation stage according to the optimal operating frequency, thereby ensuring that the induction motor maintains high efficiency during steady-state operation; then, the actual speed of the induction motor when the induction motor is running in the stable operation stage is detected in real time, and the driving voltage is adjusted according to the actual speed of the motor to dynamically maintain the steady-state operation of the induction motor, thereby achieving a significant improvement in the operating efficiency of the induction motor and a comprehensive optimization of the starting capability without increasing the cost of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0044] Figure 1 is a flow chart of a first embodiment of the induction motor control method of the present application;

[0045] Figure 2 is a schematic diagram of an equivalent circuit of an induction motor involved in an embodiment of the present application;

[0046] Figure 3 It is a multi-stage startup control flow chart involved in the embodiment of the present application;

[0047] Figure 4 It is a control process block diagram involved in the embodiment of the present application;

[0048] Figure 5 is a schematic diagram of the structure of an induction motor control device involved in an embodiment of the present application;

[0049] Figure 6 It is a schematic diagram of the structure of the induction motor control device involved in the embodiment of the present application.

[0050] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0051] The present application provides an induction motor control method, referring to Figure 1 As shown, Figure 1 It is a flowchart of the first embodiment of the induction motor control method of the present application.

[0052] Here, exemplary embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0053] Induction motors are used in many fields due to their simple structure, good reliability, stable performance, and simple control procedures of the drive controller. However, the starting torque of this motor is low. In order to reduce operating risks, many motors are operated at light loads that are significantly lower than their rated loads in daily operation. The efficiency of induction motors at light loads is relatively low.

[0054] When the induction motor needs to be controlled in speed, an electronic inverter is usually used to drive the induction motor through frequency conversion. In order to solve the problem of insufficient starting torque of the induction motor, the current redundancy of the inverter must be large to increase the starting torque of the motor by increasing the starting current. This requires increasing the safe current capacity of the power semiconductor of the inverter, which also increases the cost of the inverter.

[0055] To solve the above-mentioned defects, the present application provides an induction motor control method, device, equipment and storage medium.

[0056] The induction motor control method provided in the present application can be applied to a motor driver electrically connected to an induction motor, and can also be executed by an induction motor control device that drives and controls the induction motor. Specifically, the control center in the terminal device executes the following induction motor control method. In addition, 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 the present application is a T-type equivalent circuit composed of a stator branch, a rotor branch, and an excitation branch. The execution subject of the present application will not be repeated in the following embodiments.

[0057] In addition, participating Figure 2 , Figure 2 This is a schematic diagram of an equivalent circuit of an induction motor involved in the embodiment of the present 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. Among them, S in the rotor branch is the slip rate of the motor speed.

[0058] The induction motor control method of the present application may include steps S10 to S30:

[0059] Step S10: Obtain 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 according to the initial equivalent parameters, and determine the starting voltage according to the optimal starting frequency and a 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.

[0060] In this embodiment, before starting the induction motor (i.e., before the induction motor enters the starting operation stage), the motor driver provided in the present 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 the subsequent determination of the optimal starting frequency; then, the optimal starting frequency of the induction motor can be accurately obtained based on the initial equivalent parameters, and the starting voltage is determined based on the optimal starting frequency and the safe starting current required by the induction motor (i.e., the preset safe starting current), and then the induction motor is started according to the optimal starting frequency and the starting voltage, so that the induction motor enters the starting operation stage. This not only ensures the smoothness of the induction motor starting process, but also effectively shortens the starting time of the induction motor, reduces the energy loss of the induction motor in the starting operation stage, and effectively improves the starting ability of the induction motor.

[0061] 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 the operation of automatic parameter identification. The preset safe starting current is also customized according to application requirements, and this application does not impose any restrictions here.

[0062] 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-computer interaction interface, that is, the initial equivalent parameters are preset, then the optimal starting frequency of the induction motor is determined based on 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 based on 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.

[0063] When the initial equivalent parameters of the induction motor when the motor speed is zero are obtained through the operation of automatic parameter identification, the voltage data and current data of the induction motor in the starting operation stage are first obtained, and the stator branch, the rotor branch and the excitation branch are respectively subjected to parameter identification processing according to the voltage data and the current data to obtain the stator equivalent parameters, the rotor equivalent parameters and the excitation equivalent parameters of the induction motor in the starting operation stage, and the stator equivalent parameters, the rotor equivalent parameters and the excitation equivalent parameters of the induction motor in the starting operation stage are used as the initial equivalent parameters of the induction motor in the starting operation stage; next, the optimal starting frequency of the induction motor is determined according to the initial equivalent parameters and a 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; then, the induction motor is started according to the optimal starting frequency and the starting voltage to ensure that the induction motor can be started with the most suitable starting voltage and the optimal starting frequency in the starting operation stage, thereby avoiding problems such as motor overload, vibration or damage caused by improper setting of the starting parameters. At the same time, reasonable starting voltage and optimal starting frequency can effectively reduce the energy consumption and wear of the induction motor during startup, increase the service life of the induction motor, and enhance the dynamic response capability of the induction motor, so that the induction motor can enter the stable operation stage faster, thereby improving the operating efficiency and stability of the induction motor.

[0064] It should be noted that the preset startup frequency algorithm includes formula (1) and formula (2), wherein formula (1) is as shown below:

[0065]

[0066] Wherein, n is the motor speed of the induction motor, and n=0 means that the motor speed of the induction motor is zero; Z1 refers to the stator equivalent impedance of the induction motor during the starting operation stage, and R1 and L1 are the stator equivalent parameters of the induction motor during the starting operation stage; ω is the angular frequency of the starting current I1 required by the induction motor, and the starting current I1 refers to the current value flowing through the stator branch of the induction motor when the motor speed is zero; Z2 refers to the rotor equivalent impedance of the induction motor during the starting operation stage, and R2 and L2 are the rotor equivalent parameters of the induction motor during the starting operation stage; Z m Refers to the excitation equivalent impedance of the induction motor during the startup phase, R m and L m is the excitation equivalent parameter of the induction motor during the startup operation stage; j is an imaginary unit, which is a fixed value and can be customized according to user needs; m1 is the number of phases of the stator winding of the stator branch, ρ is the number of magnetic pole pairs of the induction motor; T emstis the starting torque of the induction motor when the motor speed is zero, and the starting torque is also called the motor electromagnetic torque of the induction motor during the starting operation stage. In addition, R1 is the resistance value of the resistor R1 of the stator branch during the starting operation stage, and L1 is the inductance value of the inductor L1 of the stator branch during the starting operation stage; R2 is the resistance value of the resistor R2 of the rotor branch during the starting operation stage, and L2 is the inductance value of the inductor L2 of the rotor branch during the starting operation stage; R m is the resistance value of the resistor Rm of the excitation branch during the starting operation stage, L2 is the inductance value of the inductor Lm of the excitation branch during the starting operation stage; I2 is the current value flowing through the rotor branch of the induction motor when the motor speed is zero; is the phase of the rotor current I2, Z d It refers to the equivalent impedance of the rotor branch and the excitation branch in parallel when the motor speed is zero.

[0067] Formula (2) is as follows:

[0068]

[0069] Among them, f s0 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; I1 = 1 st It refers to the induction motor in the first starting operation stage 1 st The starting current I1 when n=0 means that the motor speed of the induction motor is zero; T emst is the starting torque of the induction motor when the motor speed is zero; I2 is the current value flowing through the rotor branch of the induction motor when the motor speed is zero.

[0070] In yet another embodiment, referring to Figure 3 , Figure 3 It is a multi-stage startup control flow chart involved in the embodiment scheme of the present application. The startup operation stage can be divided into multiple operation stages, for example, startup operation "stage 1", startup operation "stage 2", startup operation "stage..." and startup operation "stage M", wherein each startup operation "stage *" includes the starting speed of the motor speed and the final speed of the motor speed, and the final speed of each startup operation stage is the starting speed of the next startup operation stage of the startup operation stage. In addition, the final speed of the last startup 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. Exemplarily, Figure 3 The starting speed of stage 1 is n=0 and the final speed is n=n s1 , the starting speed of stage 2 is n = n s1And the final speed is n = n s2 , ..., the starting speed of stage M is n = n s(M-1) And the final speed is n = n sM In addition, phase M refers to the last startup phase, and the final speed n in phase M is sM is the stable operating speed n of the induction motor in the stable operation stage e , or a speed close to the stable operating speed n e The value of .

[0071] For example, when the induction motor is adjusted from a state where the motor speed is n1, for example, n1=0, to another state where the speed is n2, the optimal starting frequency f is linearly increased from the n1 state within the set time T. s0 When the starting voltage V1 is adjusted to the optimum frequency f in the n2 state s1 and the driving voltage V2; while the time T is predetermined and input according to the system's moment of inertia and load conditions.

[0072] Step S20: obtaining the motor starting speed of the induction motor during the starting operation stage. When the motor starting speed is accelerated to be consistent with the preset stable operation speed, it is determined that the induction motor switches from the starting operation stage to the stable operation stage, and the voltage and current data of the induction motor during the stable operation stage are obtained. According to the voltage and current data, the parameters of the stator branch, the rotor branch and the excitation branch are respectively identified, and the optimal operating frequency of the induction motor is determined according to the identified parameters.

[0073] In this embodiment, after the starting voltage determined according to the optimal starting frequency and the required safe starting current enables the induction motor to enter the starting operation stage, the motor starting speed of the induction motor in the starting operation stage is collected according to the preset speed collection frequency until the collected motor starting speed is accelerated to the stable operation speed n of the induction motor in the stable operation stage. e equal to, or at the stable operating speed n e The corresponding speed is within the allowable error range (i.e. a speed close to the stable operating speed n e ), it is determined that the motor starting speed is accelerated to be consistent with the preset stable operating speed, and then it can be determined that the induction motor switches efficiently and smoothly from the starting operation stage to the stable operation stage; next, the voltage and current data of the induction motor in the stable operation stage are obtained, and the stator branch, rotor branch and excitation branch are efficiently identified according to 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 according to the identified parameters.

[0074] It should be noted that the voltage and current data may include voltage data and current data, wherein the voltage data may represent the operating current, and the current data may represent the driving voltage.

[0075] In a specific embodiment, when it is determined that the motor starting speed is accelerated to be consistent with the preset stable running speed, the induction motor is turned on at the motor starting speed being the stable running speed n. e , or close to the stable operating speed n e The current value flowing through the stator branch is used as the operating current, and the optimal operating frequency is calculated according to the operating current and a preset optimal frequency calculation algorithm, and the driving voltage is calculated according to the optimal operating frequency and the operating current; then, the induction motor is driven to operate in a steady state according to the optimal operating frequency and the driving voltage, ensuring that the induction motor maintains high efficiency in 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.

[0076] It should be noted that the stable operating speed of the induction motor during the stable operating stage is a constant value, which can be customized according to application requirements.

[0077] The preset optimal frequency calculation algorithm includes formula (3) and formula (4), wherein formula (3) is as follows:

[0078]

[0079] Where n = n sM It means that the motor speed of the induction motor is the final speed n in stage M sM , (i.e., the motor starting speed); I1′ refers to the motor starting speed being the stable operating speed n e Or close to the stable operating speed n e The current value flowing through the stator branch at the time of starting is the running current; ω is the angular frequency of the running current I1′; Z2 refers to the rotor equivalent impedance of the induction motor during the starting operation stage, and R2 is the resistance value of the resistor R2 of the rotor branch during the starting operation stage; Z m It refers to the excitation equivalent impedance of the induction motor during the startup and operation stage, m1 is the number of phases of the stator winding of the stator branch, and ρ is the number of magnetic pole pairs of the induction motor; T ems1 The starting speed of the motor is the stable running speed n e Or close to the stable operating speed n e The operating torque at The starting speed of the motor is the stable running speed n e Or close to the stable operating speed n e The phase of the rotor current I2' flowing through the rotor branch at this time, S is the motor starting speed and the stable running speed n eOr close to the stable operating speed n e The slip rate of the rotor speed in the rotor branch.

[0080] Formula (4) is as follows:

[0081]

[0082] Among them, f sM is the optimal operating frequency, that is, the final speed n of the induction motor in stage M sM For stable running speed n e Or close to the stable operating speed n e The frequency that can produce the maximum "torque / current ratio" when I1′=1 sM It refers to the running current I1′ of the induction motor in the last starting operation stage (i.e. stage M); I2 is the running current I1′ of the induction motor at the final speed n sM For stable running speed n e Or close to the stable operating speed n e The current value flowing through the rotor branch at this time.

[0083] Step S30: driving the induction motor to operate in the stable operation stage according to the optimal operating frequency, obtaining the actual motor speed of the induction motor when operating in the stable operation stage, and adjusting the driving voltage according to the actual motor speed to maintain the steady-state operation of the induction motor.

[0084] In this embodiment, after the induction motor is driven to operate continuously in a steady state according to the optimal operating frequency and driving voltage, the actual motor speed of the induction motor in the steady state operation stage is detected in real time, that is, the driving voltage of the induction motor is adjusted by real-time detection of the actual motor speed of the induction motor in the steady state operation to dynamically maintain the steady state operation of the induction motor, thereby achieving a significant improvement in the operating efficiency of the induction motor and a comprehensive optimization of the starting capability without increasing the cost of the inverter.

[0085] Further, in another embodiment, referring to Figure 4 , Figure 4 The induction motor control method provided in the present application also includes steps 100 to 400.

[0086] Step 100: When the motor starts running, the optimal starting frequency f is calculated according to the motor parameters when the speed is zero. s0 Calculate the starting voltage Vso of the motor according to the motor parameters and the required safe starting current. Use the optimal starting frequency f s0 And the starting voltage Vso to start the motor.

[0087] Step 200: The motor starts to reach the required stable running speed n e When the motor speed is zero, the speed is n e The optimal operating frequency f sM In the preset time Tsr, the starting frequency changes linearly from f s0 Modulate to f sM , and the driving voltage is adjusted from Vso to a preset stable operating voltage Vr.

[0088] Step 300: The motor speed is n e When the motor is in steady-state operation, the drive frequency is fine-tuned several times regularly. Each time the frequency is adjusted, the drive voltage and drive current of the motor are sampled and analyzed to establish and solve the simultaneous equations about the motor parameters. The optimal drive frequency f at the current speed is calculated using the obtained motor parameters. ro (ie the best actual frequency f se ).

[0089] Step 400: The motor speed is n e When the motor is in steady-state operation, the optimal frequency fro is used to drive the motor. During steady-state operation, the motor parameters are constantly calculated, the motor speed is observed, and the current fro is calculated according to the new motor parameters. If the motor speed deviates from the required speed n e , the motor speed is adjusted by adjusting the driving voltage so that the motor can run stably at ne.

[0090] In summary, the present application provides an induction motor control method to achieve significant improvement in the operating efficiency of the induction motor and optimization of the starting capability. Specifically, in order to improve the characteristic of insufficient starting torque during motor operation, the present application can accurately obtain the initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero through the motor driver provided by the present application, and achieve smooth and efficient starting of the induction motor based on the optimal starting frequency obtained according to the initial equivalent parameters, and the starting voltage determined in combination with the preset safe starting current, thereby significantly improving the starting capability of the induction motor; next, after starting the induction motor according to the optimal starting frequency and starting voltage to enter the starting operation stage, the motor starting speed of the induction motor is detected in real time. When the motor starting speed is accelerated to be consistent with the preset stable operating speed, it indicates that the induction motor has successfully transitioned from the starting stage to the stable operation stage, and then The voltage and current data of the induction motor in the stable operation stage are obtained, and the parameters of the stator branch, the rotor branch and the excitation branch are efficiently identified according to the voltage and current data, and the optimal operating frequency of the induction motor can be accurately obtained according to the identified parameters; next, the induction motor is driven to operate in the stable operation stage according to the optimal operating frequency, thereby ensuring that the induction motor maintains high efficiency during steady-state operation; then, the actual speed of the induction motor when the induction motor is running in the stable operation stage is detected in real time, and the driving voltage is adjusted according to the actual speed of the motor to dynamically maintain the steady-state operation of the induction motor, thereby achieving a significant improvement in the operating efficiency of the induction motor and a comprehensive optimization of the starting capability without increasing the cost of the inverter.

[0091] Furthermore, based on the first embodiment of the induction motor control method of the present application, a second embodiment of the induction motor control method of the present application is proposed.

[0092] Furthermore, in some feasible embodiments, the above step S30: adjusting the driving 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:

[0093] Step S301: 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.

[0094] In this embodiment, the updated equivalent parameters of the induction motor during steady-state operation are obtained and it is detected whether the actual motor speed deviates from the preset stable operating speed. The actual motor speed of the induction motor can be compared with the preset steady-state operating speed in real time. Once a deviation is found, 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.

[0095] Step S302: If the actual speed of the motor deviates from the stable operation speed, adjusting the driving voltage according to the updated equivalent parameter to maintain the steady-state operation of the induction motor.

[0096] In this embodiment, if the actual motor speed of the induction motor deviates from the stable operating speed during the steady-state operation stage, the driving voltage is adjusted according to the updated equivalent parameters, so that the actual motor speed of the induction motor returns to and stably maintains the same as the preset stable operating speed, so as to maintain the steady-state operation of the induction motor, thereby ensuring the continuity and stability of the steady-state operation of the induction motor.

[0097] Step S303: If the actual motor speed does not deviate from the stable operation speed, it is determined that the induction motor maintains steady-state operation.

[0098] In this embodiment, if the actual motor speed of the induction motor in the steady-state operation stage does not deviate from the stable operation speed, the induction motor is continuously driven according to the optimal operation frequency and driving voltage to maintain the steady-state operation.

[0099] Furthermore, 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:

[0100] Step S3021: fine-tune the driving frequency of the induction motor during steady-state operation at the current fine-tuning moment to obtain the current fine-tuning frequency, collect the historical fine-tuning frequencies obtained by fine-tuning the driving frequency of the induction motor during steady-state operation at the previous fine-tuning moment before the current fine-tuning moment, and collect the future fine-tuning frequencies obtained by fine-tuning the driving frequency of the induction motor during steady-state operation at the next fine-tuning moment before the current fine-tuning moment.

[0101] In this embodiment, after determining that the induction motor starts at a speed n that is stable in operation, e , or close to the stable operating speed n e After the induction motor is in steady-state operation, the driving frequency of the induction motor in steady-state operation is fine-tuned multiple times regularly to obtain multiple fine-tuning frequencies, thereby providing complete data support for the subsequent sampling and analysis of the voltage and current of the induction motor in steady-state operation. Specifically, the driving frequency of the induction motor in steady-state operation is fine-tuned at the current moment to obtain the current fine-tuning frequency, and the historical fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor in steady-state operation at the previous fine-tuning moment of the current fine-tuning moment is collected, and the future fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor in steady-state operation at the next fine-tuning moment of the current fine-tuning moment is collected, thereby ensuring the timeliness and continuity between the multiple fine-tuning frequencies.

[0102] Furthermore, in another embodiment, the historical fine-tuning frequency is (1-ΔL)f, where f is the current fine-tuning frequency and ΔL is a value in the interval (0.01, 0.5); the future fine-tuning frequency is (1+ΔH)f, where f is the current fine-tuning frequency and ΔH is a value in the interval (0.01, 0.5).

[0103] Step S3022: constructing a full-rank simultaneous equation group of equivalent parameters according to the current fine-tuning frequency, the historical fine-tuning frequency and the future fine-tuning frequency.

[0104] In this embodiment, a full-rank system of simultaneous equations of equivalent parameters is constructed by using the current results 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, thereby providing complete data for the subsequent acquisition of updated equivalent parameters of the induction motor to form a full-rank system of equations (i.e., a full-rank system of simultaneous equations of equivalent parameters).

[0105] Step S3023: determining updated equivalent parameters of the induction motor according to the full-rank simultaneous equations of equivalent parameters.

[0106] In this embodiment, by solving the set of simultaneous equations, the updated equivalent parameters of the induction motor can be accurately and quickly determined, so that the steady-state operation of the induction motor can be dynamically maintained based on the obtained updated equivalent parameters, ensuring that the induction motor can achieve optimal performance in actual operation.

[0107] Further, in some feasible embodiments, the above step S3022: constructing a full-rank system of equivalent parameter simultaneous equations according to 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:

[0108] Step A10: respectively acquiring a current driving voltage and a current driving current of the induction motor at the current fine-tuning frequency, a historical driving voltage and a historical driving current of the induction motor at the historical fine-tuning frequency, and a future driving voltage and a future driving current of the induction motor at the future fine-tuning frequency;

[0109] In this embodiment, discrete Fourier analysis is used and a preset current calculation algorithm is adopted to respectively 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 is also used and a preset voltage calculation algorithm is adopted to respectively 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.

[0110] For example, taking the calculation of the current driving current under the current fine-tuning frequency as an example, the fundamental wave I of the current driving current is calculated. i The sinusoidal component I s and cosine component I c , and the phase angle of the current driving current The preset current calculation algorithm is shown in the following formula (5):

[0111]

[0112] Among them, I i is the fundamental wave of the current driving current under the current fine-tuning frequency, I s is the sinusoidal component of the current driving current, I c is the fundamental wave of current I i The cosine component of is the current driving current I i phase angle, Δt is the interval time of current drive current sampling, N is the sampling frequency of current drive current, i(k*Δt) is the current peak value i reached when the induction motor is sampled at the Kth sampling frequency and the interval time Δt is obtained in the steady-state operation stage.

[0113] In another embodiment, taking the calculation of the current driving current under the current fine-tuning frequency as an example, the sinusoidal component U of the fundamental wave U1 of the current driving voltage is calculated. s and cosine component U c , and the phase angle of the current driving current The preset voltage calculation algorithm is shown in the following formula (6):

[0114]

[0115] Among them, U s is the sinusoidal voltage component of the fundamental wave U1 of the current drive voltage, U c is the cosine component of the fundamental wave U1, for Figure 2 The voltage phase angle of the current drive voltage U1 is shown, U1 is the fundamental wave of the current drive voltage U1, Δt is the sampling interval of the current drive voltage U1, and the sampling interval of the current drive voltage U1 is the same as the sampling interval of the current drive current I1′; N is the sampling frequency of the current drive voltage U1, and the sampling frequency of the current drive voltage U1 is the same as the sampling frequency of the current drive current I1′, and u(k*Δt) is the voltage peak value u reached at the interval Δt when the induction motor is sampled at the Kth sampling frequency in the steady-state operation stage.

[0116] Step A20: constructing a current equivalent parameter model according to the current fine-tuning frequency, the current driving voltage and the current driving current, constructing a historical equivalent parameter model according to the historical fine-tuning frequency, the historical driving voltage and the historical driving current, and constructing a future equivalent parameter model according to the future fine-tuning frequency, the future driving voltage and the future driving current;

[0117] 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.

[0118] It should be noted that the current equivalent parameter model is shown in the following formula (7):

[0119]

[0120] Among them, f id1 Refers to the current fine-tuning frequency; Z 11 is the stator branch at the current fine-tuning frequency f id1 The stator equivalent impedance, R 1’ and L 1’ is the stator equivalent parameter of the induction motor in the steady-state operation stage; Z 21 The rotor branch is at the current fine-tuning frequency f id1 The rotor equivalent impedance, R 2’ and L 2’ is the rotor equivalent parameter of the induction motor in the steady-state operation stage; Z m1 The excitation branch is at the current fine-tuning frequency f id1 The excitation equivalent impedance, R m’ and L m’ is the excitation equivalent parameter of the induction motor in the steady-state operation stage; is the current fine-tuning frequency f id1 The phase quantity of the stator current (i.e. the current driving current) flowing through the stator branch at the time, is the current fine-tuning frequency f id1 The phase quantity of the stator voltage (i.e., the current driving voltage) acting on both ends of the stator branch when Z d1 is the current fine-tuning frequency f id1 The equivalent impedance of the rotor branch and the excitation branch in parallel, S1 is the current fine-tuning frequency f id1 The slip rate of the rotor speed in the rotor branch.

[0121] It should be noted that the historical equivalent parameter model is shown in the following formula (8):

[0122]

[0123] Among them, f id2 refers to the historical fine-tuning frequency; Z 12 is the stator branch in the historical fine-tuning frequency f id2 The stator equivalent impedance, R 1’ and L 1’ is the stator equivalent parameter of the induction motor in the steady-state operation stage; Z 22 The rotor branch is at the historical fine-tuning frequency f id2 The rotor equivalent impedance, R 2’ and L 2’ is the rotor equivalent parameter of the induction motor in the steady-state operation stage; Z m2 The excitation branch is at the historical fine-tuning frequency f id2 The excitation equivalent impedance, R m’ and L m’ is the excitation equivalent parameter of the induction motor in the steady-state operation stage; is the historical fine-tuning frequency f id2 The phasor of the stator current (i.e., the historical driving current) flowing through the stator branch at time , is the historical fine-tuning frequency f id2 The phasor of the stator voltage (i.e., historical drive voltage) acting on both ends of the stator branch at the time, S2 is the phasor of the stator voltage (i.e., historical drive voltage) acting on both ends of the stator branch at the time, S3 is the phasor of the stator voltage (i.e., historical drive voltage) acting on both ends of the stator branch at the time, S4 is the phasor of the stator voltage (i.e., historical drive voltage id2 The slip rate of the rotor speed in the rotor branch.

[0124] The future equivalent parameter model is shown in the following formula (9):

[0125]

[0126] Among them, f id3 Refers to the future fine-tuning frequency, Z 13 Fine-tune the frequency f for the stator branch in the future id3 The stator equivalent impedance, R 1’ and L 1’ is the stator equivalent parameter of the induction motor in the steady-state operation stage; Z 23 Fine-tune the frequency f of the rotor branch in the future id3 The rotor equivalent impedance, R 2’ and L 2’ is the rotor equivalent parameter of the induction motor in the steady-state operation stage; Z m3 To fine-tune the frequency f of the excitation branch in the future id3 The excitation equivalent impedance, R m’ and L m’ is the excitation equivalent parameter of the induction motor in the steady-state operation stage; To fine-tune the frequency f in the futureid3 The phasor of the stator current (i.e., the future driving current) flowing through the stator branch at time , To fine-tune the frequency f in the future id3 The phase quantity of the stator voltage (i.e., the future driving voltage) acting on both ends of the stator branch at the time, S3 is the phase quantity of the future fine-tuning frequency f id3 The slip rate of the rotor speed in the rotor branch.

[0127] Step A30: Perform model simultaneous 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 group.

[0128] In this embodiment, model joint processing is performed based on the historical equivalent parameter model and the future equivalent parameter model to obtain a full-rank equivalent parameter joint equation group consisting of formulas (7) to (9), thereby solving the updated equivalent parameters of the induction motor under the current conditions.

[0129] Further, in some feasible embodiments, the above step S3023: determining the updated equivalent parameters of the induction motor according to the full-rank equivalent parameter simultaneous equations, may also include the following implementation steps B10 to B20:

[0130] Step B10: performing parameter identification processing on the stator branch, the rotor branch and the excitation branch respectively according to the full-rank equivalent parameter simultaneous equations to obtain stator equivalent parameters, rotor equivalent parameters and excitation equivalent parameters of the induction motor in a steady-state operation stage;

[0131] Step B20: using the stator equivalent parameter, the rotor equivalent parameter and the excitation equivalent parameter as updated equivalent parameters of the induction motor.

[0132] In this embodiment, after determining the full-rank equivalent parameter simultaneous equations, the error of solving the nonlinear equation is accumulated, and it is detected whether the error is greater than the preset error threshold. If the error is less than or equal to the preset error threshold, the full-rank equivalent parameter simultaneous equations composed of formulas (7) to (9) are completed to perform parameter identification processing on the stator branch, rotor branch and excitation branch, and the stator equivalent parameters of the stator branch in the steady-state operation stage, the rotor equivalent parameters of the rotor branch in the steady-state operation stage and the excitation equivalent parameters of the excitation branch in the steady-state operation stage can be accurately obtained, and the stator equivalent parameters, rotor equivalent parameters and excitation equivalent parameters are used as the updated equivalent parameters of the induction motor. Such processing can not only ensure the accuracy of the parameter identification processing, but also improve the response speed of the parameter identification processing, ensuring that the induction motor can achieve the optimal performance state in actual operation.

[0133] In another embodiment, if the number of iterations of the nonlinear equation is greater than a preset iteration threshold, the solution obtained is the solution to the system of equations. Such processing can improve the adaptability and robustness of parameter identification, and can adjust the strategy in time when the data is abnormal or the model does not match, thereby ensuring the stability and accuracy of the entire parameter identification process.

[0134] It should be noted that when the induction motor is in a stable operation stage, 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 calculation can be simplified. For example, if only R1 and L1, and R2 and L2 are considered, the current fine-tuning frequency f id1 and the historical fine-tuning frequency f id2 The simultaneous equations established by equations (7) and (8) are solved to calculate the equivalent parameters of the stator branch and the equivalent parameters of the rotor branch.

[0135] In addition, when the induction motor is in the stable operation stage, since the equivalent impedance of the induction motor is related to the motor's driving voltage, driving current, load characteristics and environment, in order to achieve accurate control of the induction motor, the parameter identification operation should be performed frequently when the calculation speed of the controller's MCU allows.

[0136] Furthermore, 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:

[0137] Step C10: Based on the updated equivalent parameters, the optimal actual frequency of the induction motor at the stable operating speed can be accurately obtained.

[0138] In this embodiment, the optimal actual frequency of the induction motor at a stable operating speed can be accurately obtained according to the updated equivalent parameters and the preset optimal frequency calculation algorithm.

[0139] It should be noted that the updated equivalent parameters at least include the stator equivalent parameters, the rotor equivalent parameters and the excitation equivalent parameters of the induction motor in the steady-state operation stage.

[0140] The preset optimal frequency calculation algorithm includes at least formula (10) and formula (11), wherein formula (10) is as shown below:

[0141]

[0142] Where n = n e It means that the motor speed of the induction motor is the stable operating speed n e; Z 1e The stator branch is running at a stable speed n e The stator equivalent impedance, R 1’ and L 1’ is the stator equivalent parameter of the induction motor in the steady-state operation stage; Z 2e The rotor branch is running at a stable speed n e The equivalent impedance, R 2’ and L 2’ is the rotor equivalent parameter of the induction motor in the steady-state operation stage; Z me The excitation branch is at a stable operating speed n e The excitation equivalent impedance, R m’ and L m’ is the excitation equivalent parameter of the induction motor in the steady-state operation stage; j is the imaginary unit; ω e The stator branch is running at a stable speed n e The angular frequency of the stator current I1 at this time, and the stator current I1 at this time refers to the induction motor at a stable operating speed n e The unit current I flowing through the stator branch N ; m1 is the number of phases of the stator winding of the stator branch, ρ is the number of magnetic pole pairs of the induction motor; T emse The induction motor is running at a stable speed n e The electromagnetic torque of the motor at 2e The rotor branch is running at a stable speed n e The current value at is the rotor current I 2e The phasor, Z de It means that when the motor speed is stable running speed n e The equivalent impedance of the rotor branch and the excitation branch in parallel.

[0143] Formula (11) is as follows:

[0144]

[0145] Among them, f se is the optimal actual frequency of the induction motor, I1=1 N The motor speed of the induction motor is the stable operating speed n e The unit current I flowing through the rotor branch N , n=n e It means that the motor speed of the induction motor is the stable operating speed n e , I 2e The rotor branch is running at a stable speed n e The current value at .

[0146] In addition, it should be noted that the calculation algorithm used to calculate the adjusted driving voltage is shown in the following formula (12):

[0147] U d =[d u *(n c -n e )]*U1

[0148] Among them, U d is the adjusted driving voltage; d u It is a preset proportional increment of the adjustment voltage, which can be customized according to application requirements. This application does not impose any restrictions on this; n c is the actual speed of the motor; n e To stabilize the operating speed; U1 is the driving voltage.

[0149] Step C20: After driving the induction motor according to the optimal actual frequency, adjusting the driving 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 driving voltage and the optimal actual frequency.

[0150] In this embodiment, after the induction motor is driven 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, 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 stage, thereby significantly improving the stability and energy efficiency of the induction motor operation without increasing the cost of the inverter.

[0151] Further, in some feasible embodiments, in the above step C20: maintaining the steady-state operation of the induction motor according to the adjusted driving voltage and the optimal actual frequency, the following implementation steps C201 to C203 may also be included:

[0152] Step C201: driving the induction motor to operate according to the optimal actual frequency and the adjusted driving voltage to obtain a current motor speed of the induction motor;

[0153] Step C202: taking the current speed of the motor as the next actual speed of the motor, returning to execute the step of detecting whether the actual speed of the motor deviates from the stable operating speed, and accumulating the number of times the execution is returned.

[0154] In this embodiment, the induction motor is driven to operate according to the optimal actual frequency and the adjusted driving voltage, so that the current speed of the induction motor can be accurately obtained, and the current speed of the motor is 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 execute, which is conducive to the stable operation of the induction motor.

[0155] Step C203: until it is detected within a preset return number threshold that the actual speed of the motor does not deviate from the stable operating speed, the optimal driving frequency and actual driving voltage of the induction motor at the actual speed of the motor are obtained, and the induction motor is driven according to the optimal driving frequency and the actual driving voltage to maintain steady-state operation.

[0156] In this embodiment, when it is detected within a preset return number threshold that the actual speed of the motor does not deviate from the stable operating speed, the optimal driving frequency and the actual driving voltage of the induction motor at the actual speed of the motor can be automatically obtained. By driving the induction motor according to the optimal driving frequency and the actual driving voltage to maintain steady-state operation, it is ensured that the induction motor can continue to operate in an efficient and stable state, thereby significantly improving the reliability and energy efficiency of the motor operation.

[0157] In summary, when the motor enters the steady-state operation stage, unlike the variable frequency control of traditional induction motors, the driving frequency and driving voltage of the induction motor driver of the present application are determined by the load, the real-time parameters of the motor and the required motor speed. When the motor starts, the required "allowable starting current" can produce a larger starting torque; when the motor is running in a steady state, the copper loss of the motor can be reduced to a smaller state. Therefore, the present invention can reduce the cost of the induction motor drive controller and improve the motor efficiency. These effects are of positive significance to the application of induction motors.

[0158] In addition, the present application also provides an induction motor control device, please refer to Figure 5 , Figure 5 It is a structural schematic diagram of an induction motor control device involved in an embodiment of the present application.

[0159] The induction motor control device of the present application comprises:

[0160] A starting module H01 is used to obtain 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 according to the initial equivalent parameters, and determine the starting voltage according to the optimal starting frequency and a 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;

[0161] The steady-state operation module H02 is used to obtain the motor starting speed of the induction motor in the starting operation stage. When the motor starting speed is accelerated to be consistent with the preset stable operation speed, it is determined that the induction motor switches from the starting operation stage to the stable operation stage, and the voltage and current data of the induction motor in the stable operation stage are obtained. According to the voltage and current data, the parameters of the stator branch, the rotor branch and the excitation branch are respectively identified, and the optimal operating frequency of the induction motor is determined according to the identified parameters;

[0162] The steady-state maintaining module H03 is used to drive the induction motor to operate in the stable operation stage according to the optimal operating frequency, obtain the actual motor speed of the induction motor when it is operating in the stable operation stage, and adjust the driving voltage according to the actual motor speed to maintain the steady-state operation of the induction motor.

[0163] Each functional module of the induction motor control device of the present application implements the steps of the induction motor control method of the present application as described above during operation.

[0164] In addition, the present application also provides an induction motor control device. Figure 6 , Figure 6 The schematic diagram of the structure of the induction motor control device involved in the embodiment of the present application is shown in FIG. The induction motor control device of the embodiment of the present application may be a device for locally running the induction motor control method.

[0165] like Figure 6 As shown, the induction motor control device of the embodiment of the present application may include: a processor 1001, such as a CPU, a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a Wi-Fi interface).

[0166] The memory 1005 is arranged on the main body of the induction motor control device. The memory 1005 stores a program, and the program implements 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 memory or a stable memory (non-volatile memory), such as a disk memory. The memory 1005 can also be a storage device independent of the aforementioned processor 1001.

[0167] Those skilled in the art will understand that Figure 6 The structure of the induction motor control device shown in the figure does not constitute a limitation on the induction motor control device, and may include more or less components than those shown in the figure, or combine certain components, or arrange the components differently.

[0168] like Figure 6 As shown, the memory 1005 as a storage medium may include an operating system, a network communication module, a user interface module, and a motor control program of the induction motor control device.

[0169] exist Figure 6 In the induction motor control device shown, 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 one of the above-mentioned induction motor control methods.

[0170] In addition, the present application provides a storage medium, which is a computer-readable storage medium. The computer-readable storage medium stores a motor control program, and when the motor control program is executed by a processor, the steps of the above-mentioned induction motor control method are implemented.

[0171] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0172] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0173] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a computer-readable storage medium (such as ROM / RAM, disk, CD) as mentioned above, and includes a number of instructions for enabling an induction motor control device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0174] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An induction motor control method, characterized in that: The induction motor control method is applied to a motor driver, the motor driver is electrically connected to the induction motor, and the equivalent circuit of the induction motor includes a stator branch, a rotor branch and an excitation branch; The induction motor control method comprises: Acquire initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determine an optimal starting frequency of the induction motor according to the initial equivalent parameters, determine a starting voltage according to the optimal starting frequency and a preset safe starting current, and enable the induction motor to enter a starting operation phase according to the optimal starting frequency and the starting voltage; Acquire the motor starting speed of the induction motor in the starting operation stage, and when the motor starting speed is accelerated to be consistent with the preset stable operation speed, determine that the induction motor switches from the starting operation stage to the stable operation stage, and acquire the voltage and current data of the induction motor in the stable operation stage, perform parameter identification on the stator branch, the rotor branch and the excitation branch respectively according to the voltage and current data, and determine the optimal operating frequency of the induction motor according to the identified parameters; The induction motor is driven to operate in the stable operation stage according to the optimal operating frequency, and the actual motor speed of the induction motor when operating in the stable operation stage is obtained, and the driving voltage is adjusted according to the actual motor speed to maintain the steady-state operation of the induction motor.

2. The method according to claim 1, characterized in that The step of adjusting the driving voltage according to the actual speed of the motor to maintain the steady-state operation of the induction motor comprises: Acquire 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; If the actual speed of the motor deviates from the stable operating speed, adjusting the driving voltage according to the updated equivalent parameter to maintain the steady-state operation of the induction motor; If the actual speed of the motor does not deviate from the stable operation speed, it is determined that the induction motor maintains steady-state operation.

3. The method according to claim 2, characterized in that The step of obtaining updated equivalent parameters when the induction motor is in steady-state operation comprises: Fine-tune the driving frequency of the induction motor when it is running in a steady state at a current fine-tuning moment to obtain a current fine-tuning frequency, collect a historical fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor when it is running in a steady state at a fine-tuning moment before the current fine-tuning moment, and collect a future fine-tuning frequency obtained by fine-tuning the driving frequency of the induction motor when it is running in a steady state at a fine-tuning moment next to the current fine-tuning moment; Constructing a full-rank set of simultaneous equations of equivalent parameters according to the current fine-tuning frequency, the historical fine-tuning frequency, and the future fine-tuning frequency; The updated equivalent parameters of the induction motor are determined according to the full-rank simultaneous equations of equivalent parameters.

4. The method according to claim 3, characterized in that The step of constructing a full-rank set of simultaneous equations of equivalent parameters according to the current fine-tuning frequency, the historical fine-tuning frequency and the future fine-tuning frequency comprises: Respectively acquiring a current driving voltage and a current driving current of the induction motor at the current fine-tuning frequency, a historical driving voltage and a historical driving current of the induction motor at the historical fine-tuning frequency, and a future driving voltage and a future driving current of the induction motor at the future fine-tuning frequency; Constructing a current equivalent parameter model according to the current fine-tuning frequency, the current driving voltage, and the current driving current, constructing a historical equivalent parameter model according to the historical fine-tuning frequency, the historical driving voltage, and the historical driving current, and constructing a future equivalent parameter model according to the future fine-tuning frequency, the future driving voltage, and the future driving current; Model simultaneous processing is performed according to 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 group.

5. The method according to claim 3, characterized in that The step of determining the updated equivalent parameters of the induction motor according to the full-rank equivalent parameter simultaneous equations comprises: According to the full-rank equivalent parameter simultaneous equations, parameter identification processing is performed on the stator branch, the rotor branch and the excitation branch respectively to obtain the stator equivalent parameters, the rotor equivalent parameters and the excitation equivalent parameters of the induction motor in the steady-state operation stage; The stator equivalent parameter, the rotor equivalent parameter and the excitation equivalent parameter are used as updated equivalent parameters of the induction motor.

6. The method according to claim 2, characterized in that The step of adjusting the driving voltage according to the updated equivalent parameter to maintain the steady-state operation of the induction motor comprises: Determining the optimal actual frequency of the induction motor at the stable operating speed according to the updated equivalent parameter; 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.

7. The method according to claim 6, characterized in that The step of maintaining the steady-state operation of the induction motor according to the adjusted driving voltage and the optimal actual frequency comprises: Driving the induction motor to operate according to the adjusted driving voltage and the optimal actual frequency to obtain a current motor speed of the induction motor; Taking the current speed of the motor as the next actual speed of the motor, returning to execute the step of detecting whether the actual speed of the motor deviates from the stable operating speed, and accumulating the number of executions returned; Until it is detected within a preset return number threshold that the actual speed of the motor does not deviate from the stable operating speed, the optimal driving frequency and actual driving voltage of the induction motor at the actual speed of the motor are obtained, and the induction motor is driven according to the optimal driving frequency and the actual driving voltage to maintain steady-state operation.

8. An induction motor control device, characterized in that: The induction motor control device comprises: A starting module, used for obtaining initial equivalent parameters of the equivalent circuit of the induction motor when the motor speed is zero, determining an optimal starting frequency of the induction motor according to the initial equivalent parameters, and determining a starting voltage according to the optimal starting frequency and a preset safe starting current, and enabling the induction motor to enter a starting operation phase according to the optimal starting frequency and the starting voltage; A steady-state operation module, used to obtain the motor starting speed of the induction motor in the starting operation stage, and when the motor starting speed is accelerated to be consistent with a preset stable operation speed, it is determined that the induction motor switches from the starting operation stage to the stable operation stage, and the voltage and current data of the induction motor in the stable operation stage are obtained, and the parameters of the stator branch, the rotor branch and the excitation branch are respectively identified according to the voltage and current data, and the optimal operating frequency of the induction motor is determined according to the identified parameters; The steady-state maintaining module is used to drive the induction motor to operate in the steady-state operation stage according to the optimal operating frequency, obtain the actual motor speed of the induction motor when it operates in the steady-state operation stage, and adjust the driving voltage according to the actual motor speed to maintain the steady-state operation of the induction motor.

9. An induction motor control device, characterized in that: The induction motor control device comprises a memory, a processor and a motor control program stored in the memory and executable on the processor, and the processor implements the steps of the method according to any one of claims 1 to 7 when executing the motor control program.

10. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, on which a motor control program is stored. When the motor control program is executed by a processor, the steps of the induction motor control method according to any one of claims 1 to 7 are implemented.

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