Novel three-stage motor starting control method

Abstract

The invention belongs to the technical field of motor control, and discloses a novel three-stage motor starting control method, which utilizes a model reference adaptive position-free algorithm to estimate errors, compensates system parameters, and feeds back the system parameters to an adjustable model so as to correct the estimation errors of the position-free algorithm. Switching judgment is added in a switching algorithm, so that the problems that motor parameters are inaccurate due to iron core saturation and cross saturation effects, and large errors exist between the estimated rotating speed and the actual rotating speed of model reference self-adaption before vector control is input due to influences of an inverter, a dead zone effect and the like are solved; therefore, the problem of switching failure when the position-free algorithm is switched is solved, the actual loading capacity of the motor is improved, and the accuracy of a control strategy when the model reference self-adaptive position-free switching algorithm is loaded is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of motor control, can be used in the field of three-stage motor driving, and specifically relates to a novel three-stage motor starting control method. Background Art

[0002] During the starting and generating process of the three-stage motor, it is necessary to switch from the speed sensor / IF starting mode to the speed sensorless mode. This switching process is affected by the changes in motor parameters, measurement errors, dead zone effects, etc., resulting in a large error between the estimated speed and the actual speed of the model reference adaptive system before vector control is put into use, which in turn causes a switching failure when switching to the position-free algorithm. At the same time, the estimated error will cause the actual load capacity of the motor to decrease, affecting the normal operation of the three-stage motor starting and generating system.

[0003] In response to the above problems, this application proposes a new three-stage motor starting control method, which mainly includes a three-stage motor position sensorless starting operation control strategy, and a motor parameter error leading to a positionless algorithm estimation error, and finally proposes a positionless algorithm switching control strategy based on a speed error for the positionless algorithm switching strategy. The relevant patent documents retrieved are as follows:

[0004] 1. Patent CN115459641A discloses a three-stage motor rotor position estimation method and device. The above patent proposes a three-stage motor position sensorless algorithm strategy using a high-frequency injection method at low speed and a phase-locked loop strategy at high speed.

[0005] 2. Patent CN113472256B discloses a method for estimating the rotor position of an excitation controller of an aviation three-stage starting generator system. The above patent proposes an online speed position estimation method based on a high-frequency injection method.

[0006] 3. Patent CN113824382A discloses a rotor position fault identification and compensation method based on an aviation three-stage motor starting / generation control system. The above patent proposes a method of using the rotor position change in this cycle and the rotor position change in the previous cycle as speed compensation. Summary of the invention

[0007] In order to solve the problem of switching failure when switching the positionless algorithm, the present invention provides a novel three-level motor starting control method to improve the control accuracy of the positionless algorithm. Before the positionless algorithm is switched, the model is referenced to adaptively design the switching judgment logic of the positionless algorithm to ensure the success of the positionless algorithm switching.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A novel three-stage motor starting control method includes the following steps:

[0010] Motor controller initialization to ensure the three-stage motor is properly calibrated and adjusted before starting operation;

[0011] Perform a power-on self-test to check the normal operation of the system;

[0012] The host computer sets the speed sensorless algorithm to switch the speed value and sends the control command to the motor controller;

[0013] The controller synchronously collects the current speed and estimated speed of the motor;

[0014] Determine the switching enable state of the position-free algorithm so as to make necessary parameter compensation and switch judgment of the position-free algorithm.

[0015] As a further technical solution of the present invention, the host computer sets the algorithm as a three-level motor position-free algorithm and issues a position-free algorithm switching speed instruction.

[0016] As a further technical solution of the present invention, the estimated rotation speed is obtained by a position-free algorithm.

[0017] As a further technical solution of the present invention, after the position-free algorithm switching is enabled:

[0018] If no position algorithm switching is enabled, then the no position algorithm switching is judged;

[0019] If the no-position algorithm switching is not enabled, the no-position parameter method is used for parameter compensation.

[0020] As a further technical solution of the present invention, parameter compensation of the position-free parameter method is specifically: a model reference adaptive control strategy based on parameter compensation feedback is adopted, the position-free algorithm estimation error is utilized, the system parameters are compensated, and the error is fed back to the adjustable model of the model reference adaptive control strategy.

[0021] As a further technical solution of the present invention, after the position-free algorithm cuts and judges:

[0022] If the non-position algorithm is switched, the three-stage motor switches to the non-position algorithm operation;

[0023] If the non-position algorithm is not switched, the current-frequency algorithm is maintained.

[0024] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the steps of the control method are implemented when the processor executes the program.

[0025] A computer storage medium stores a computer program, wherein the computer program implements the steps of the control method when executed by a processor.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. It can solve the problem of inaccurate motor parameters caused by core saturation and cross saturation effects, and the problem of large errors between the estimated speed and the actual speed of the model reference adaptation before vector control due to the influence of inverter and dead zone effects.

[0028] 2. Solve the problem of switching failure when switching the position-free algorithm, improve the actual load-bearing capacity of the motor, and ensure the accuracy of the control strategy when the model reference adaptive position-free switching algorithm is loaded.

[0029] 3. The estimation error of the model reference adaptive position-free algorithm is utilized to compensate the system parameters and feed them back to the adjustable model, thereby correcting the estimation error of the position-free algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Reference schematic diagram of adaptive control for existing three-stage motor model;

[0031] Figure 2 The waveform diagram of the switching of the position-free algorithm for the three-stage motor starting process;

[0032] Figure 3 This is the graph showing the motor speed estimation error changing with the motor parameter error;

[0033] Figure 4 It is a principle diagram of the model reference adaptive control based on parameter compensation feedback of the present invention;

[0034] Figure 5 This is the relationship between the motor estimated speed error and the motor load capacity;

[0035] Figure 6 The present invention is a flow chart of the switching of the model reference adaptive algorithm based on the estimated speed error;

[0036] Figure 7 This is the electrical structure diagram of the three-stage motor control;

[0037] Figure 8 This is a novel three-stage motor starting control block diagram of the present invention;

[0038] Fig. 9 A flow chart for constructing an offline table of estimated speed and inductance parameters of the present invention;

[0039] Fig.10 The schematic diagram is a novel three-stage motor starting control method of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In a first aspect, the present invention provides a novel three-stage motor starting control method, which includes the following steps:

[0042] Motor controller initialization to ensure the three-stage motor is properly calibrated and adjusted before starting operation;

[0043] Perform a power-on self-test to check the normal operation of the system;

[0044] The host computer sets the speed sensorless algorithm to switch the speed value and sends the control command to the motor controller;

[0045] The controller synchronously collects the current speed and estimated speed of the motor;

[0046] Determine the switching enable state of the position-free algorithm so as to make necessary parameter compensation and switch judgment of the position-free algorithm.

[0047] like Figure 1 The principle block diagram of the model reference adaptation shown in the figure proposes the existing three-level motor model reference adaptive position sensorless starting operation control strategy. There are two ways to control the three-level motor position algorithm starting operation: 1. First, start the motor with a speed sensor to drag it to a certain speed and then switch to the position algorithm; 2. Through the current-frequency control method, drag the motor to a certain speed and then switch to the position algorithm.

[0048] The above two methods both adopt model reference adaptive position-free control when operating without position sensor.

[0049] It is mainly composed of an adjustable model and an adaptive law. The idea of ​​MRAS for angle identification is to use the expression without unknown parameters as the expected model, and the expression containing the parameters to be identified as the adjustable model. The two models have outputs with the same physical meaning. By using the difference between the outputs of the two models, the real-time position of the motor can be identified by designing a suitable adaptive law.

[0050] The three-stage motor starting process switches without position algorithm waveform as follows Figure 2 In the figure, the red color represents the MRAS estimated speed and angle value, and the blue color represents the motor's actual speed and angle value.

[0051] Its starting stage is divided into three processes: pre-excitation and positioning stage, current-frequency control starting stage, and model reference adaptive position-free control stage.

[0052] We design an adaptive adjustable model based on model reference, which is designed according to the motor stator voltage equation. During the operation of the motor, there are core saturation and cross-saturation effects. As the armature current continues to increase, the working point of the core magnetization curve will pass through the critical saturation zone until it reaches the saturation zone. In this process, the actual working magnetic permeability of the core decreases, the magnetic resistance of the core becomes larger and cannot be ignored, the effective magnetic permeability of the magnetic circuit decreases, and the motor inductance decreases accordingly.

[0053] If constant inductance parameters are used in the model reference adaptive algorithm in practice, it will lead to calculation errors caused by constant motor parameters. Figure 3 Shown is the estimated error due to motor parameter errors.

[0054] Since the motor parameter error will lead to the model reference adaptive estimation error, resulting in a decrease in the motor load capacity, therefore, when using the model reference adaptive position-free algorithm, the motor inductance parameters should be tested first, and the control should be performed according to the actual inductance lookup table method in the model reference adaptive.

[0055] Since the parameters cause estimation errors in the position-free algorithm, a model reference adaptive control strategy based on parameter compensation feedback is proposed, such as Figure 4 As shown in Figure 2, the MRAS estimation error is fed back as a parameter compensation term to correct the estimation error of the position-free algorithm.

[0056] The iron core saturation and cross saturation effects will lead to inaccurate motor parameters. At the same time, due to the influence of the inverter, dead zone effect, etc. in the motor control system, a series of nonlinear factors will be affected, resulting in a large error between the estimated speed and the actual speed of the model reference adaptive before the vector control is put into use, and then the switching failure occurs when switching to the position-free algorithm. Similarly, the estimated error will cause the actual load capacity of the motor to decrease. The estimated speed error and the motor load are as follows: Figure 5 shown.

[0057] Based on the above problems, we propose a model reference adaptive algorithm switching strategy based on estimated speed error. By adding constraints on the above curves to the switching algorithm for switching judgment, the control strategy accuracy of the model reference adaptive law without position switching algorithm can be achieved when the load is on. The specific process is as follows Figure 6 shown.

[0058] The embodiment of the present application provides a novel three-stage motor starting control method, which adopts a discrete table parameter error compensation method based on a model reference adaptive positionless control algorithm to improve the control accuracy of the positionless algorithm. Before switching the positionless algorithm, a switching judgment logic is designed for the model reference adaptive positionless algorithm to ensure successful algorithm switching. The electrical structure diagram of the three-stage motor control is shown in FIG. Figure 7 shown.

[0059] In this embodiment, if Figure 8 As shown, a novel three-stage motor starting control method is provided, and the method is applied to a three-stage motor starting algorithm as an example for explanation, which includes the following steps:

[0060] The motor controller is connected to the computer host computer to establish normal communication and realize real-time control of the motor. The relevant flags and parameter instructions are set by the host computer and sent to the motor controller. The motor controller executes the control algorithm according to the instructions and feeds back the state value of the motor to the host computer. The host computer displays the motor status information in real time.

[0061] The specific position-free algorithm switching control method is described as follows:

[0062] When the motor starts, the three-stage motor is first dragged to a certain speed through the current-frequency control method, and the speed value of the position-free algorithm switching point is set through the host computer. The motor controller feeds back the current motor speed information to the host computer, and the information of both is displayed in the host computer;

[0063] After the motor controller is initialized, the main exciter of the three-stage motor is set to pass the external excitation power supply to establish the air gap magnetic field. When the three-stage motor is started, the direct current is first passed through the motor phase A winding. At this time, after the motor controller sends the current control instruction, the motor rotor will be positioned to the A phase. The motor controller uploads the current motor state information to the host computer. The host computer latches the read initial positioning completion signal. After determining that the initial positioning has been completed, the host computer executes the current-frequency control method to drive the motor. The host computer sends the current control information and the frequency control information. After receiving the control instruction sent by the host computer, the motor controller drives the motor according to the control instruction. At this time, the output current and frequency of the motor controller are consistent with the instruction sent by the host computer. After receiving the frequency instruction sent by the motor controller, the motor will run to the same speed as the issued frequency instruction in a short time. Set the positionless switching speed value in the host computer, and transmit the switching speed value parameter to the motor controller. The motor controller receives the switching speed information sent by the host computer and latches the value in the register.

[0064] Furthermore, the motor controller uploads the feedback speed and the estimated speed information of the model reference adaptive positionless control method to the host computer, and enters the positionless algorithm switching judgment link.

[0065] Among them, the motor controller synchronously samples the motor real-time speed information and the model reference adaptive positionless output speed information and uploads them to the host computer. After the host computer receives the motor real-time speed and the model reference adaptive positionless algorithm estimated speed value, it triggers the positionless algorithm switching judgment algorithm. In the positionless algorithm switching judgment, the motor real-time speed value is compared with the model reference adaptive output estimated speed value. Here, the motor real-time speed value is the speed value converted from the frequency instruction sent by the host computer. When the motor real-time speed value is greater than the positionless switching speed value, the host computer sends the positionless switching flag to the motor controller. After receiving the positionless switching flag, the motor controller uses the model reference adaptive positionless algorithm output estimated speed as a control signal to realize the three-level motor positionless control method; when the motor real-time speed value is less than the positionless switching speed value, the host computer will not trigger the positionless algorithm switching flag, and the motor controller still maintains current-power control.

[0066] Furthermore, in the positionless algorithm switching enable judgment link, the model reference adaptive positionless algorithm output speed value is compared with the speed value fed back by the current state of the motor to determine whether to switch to the positionless control algorithm judgment link.

[0067] Among them, the host computer receives the real-time speed value of the motor uploaded by the motor controller and the model reference adaptive positionless output estimated speed value, triggers the judgment of the positionless control switching algorithm, in which the absolute value of the difference between the real-time speed value of the motor and the model reference adaptive output estimated speed value is taken, and the absolute value of the speed error is divided by the real-time speed value of the motor, and the division is used as a sign indicator of whether to switch the positionless control algorithm. The specific judgment logic is to compare the division value with the threshold judgment value. In the test embodiment, the motor parameter is, when the positionless algorithm switching speed value is under the working condition of 200rpm, the judgment value is set to 0.1, and a better switching effect can be obtained. When the division value is less than the threshold judgment value, the host computer sends the positionless control algorithm switching enable flag bit, and when the motor controller receives the switch positionless control algorithm switching enable flag bit sent by the host computer, the second step of the positionless algorithm switching algorithm judgment is performed. When the division value is greater than the threshold judgment value, the host computer sends the positionless control algorithm switching enable failure flag. When the controller receives the flag, the motor controller will block the positionless switching judgment logic mentioned in the second step. At this time, when the host computer continues to send the speed increase command to the controller, the controller will not enter the judgment logic of the positionless algorithm switching after receiving the updated speed command information, and will not switch to the positionless algorithm operation.

[0068] Furthermore, when the positionless control algorithm switching enable judgment fails, the model reference adaptive positionless algorithm parameter compensation strategy is entered to compensate the model reference adaptive internal parameters, and then the model reference adaptive output speed is fed back to the host computer. The above operation is repeated until the switching judgment logic is met, and the three-stage motor can realize the positionless algorithm switching.

[0069] Among them, when the position-free control algorithm fails to enable the switching judgment of the position-free control algorithm, the host computer's position-free algorithm parameter compensation flag is triggered at this time. When the motor controller receives the flag sent by the host computer, the host computer will first control the speed to maintain a speed value below the position-free algorithm speed switching point, and at the same time, the model reference adaptive output speed is subtracted from the current running feedback speed of the motor. By subtracting the model reference adaptive output speed from the current running feedback speed of the motor, the speed difference is used as input. After receiving the speed difference signal, the parameter compensation feedback link obtains the parameters in the adaptive model in the model reference adaptive algorithm through offline table lookup for compensation.

[0070] In this embodiment, the offline table lookup method used is described in detail, and the offline parameter table construction process is as follows: Fig. 9As shown, when constructing the offline table, first, in the three-level motor vector control algorithm with a rotary transformer, the open-loop operation model refers to the adaptive model in the adaptive algorithm, and by changing the inductance parameters in the adaptive model, the observation model refers to the adaptive algorithm output estimated speed change law, the output estimated speed change and the inductance parameter are matched one by one, and the offline table is organized.

[0071] The specific implementation method is as follows: The adjustable model equivalent stator voltage equation is:

[0072]

[0073] In the above formula, u d 、u q To sample the current voltage value, i d 、i q To sample the current current value, the estimated speed information without position algorithm in the equation can be obtained by calculating the electrical angle, and the calculation equation is: p is the number of motor pole pairs. The change in electrical angular velocity (w e ±Δw) is related to the inductance parameter change value (L±ΔL). When constructing the discrete table, it is obtained by calibrating the relationship between Δw and ΔL. When the corresponding speed error input occurs, the compensation value of the inductance parameter can be obtained by checking the offline table. The advantage of choosing the inductance parameter as the offline table is that the inductance parameter can reflect the saturation response of the internal magnetic circuit of the motor. During the operation of the motor, the inductance value often changes with the change of current.

[0074] In this example, the real-time speed value of the motor obtained by the three-stage motor current-frequency control method is compared with the estimated speed value of the model reference adaptive positionless algorithm, and the ratio of the speed difference to the real-time speed value of the motor is recorded. This ratio is stored and updated and written to the host computer, so that the host computer can judge whether the switching conditions of the positionless algorithm are met based on the result. When the three-stage motor does not meet the switching conditions, a method for compensating the inductance parameters in the adaptive model in the model reference adaptive positionless algorithm is further proposed to adjust the estimated speed output by the model reference adaptive positionless algorithm to meet the switching conditions of the positionless algorithm so that the subsequent switching algorithm can control the motor.

[0075] A new three-stage motor starting control strategy proposed in an embodiment of the present invention can solve the problem of inaccurate motor parameters caused by core saturation and cross-saturation effects, and the problem of large error between the estimated speed and the actual speed of the model reference adaptive before vector control due to the influence of the inverter and dead zone effects, thereby solving the problem of switching failure when switching the positionless algorithm, improving the actual load-bearing capacity of the motor, and ensuring the accuracy of the control strategy when the model reference adaptive positionless switching algorithm is loaded.

[0076] In a second aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the control method when executing the program.

[0077] In a third aspect, the present invention provides a computer storage medium having a computer program stored thereon, characterized in that the computer program implements the steps of the control method when executed by a processor.

[0078] So far, the purpose of the present invention has been achieved.

[0079] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A novel three-stage motor starting control method, characterized in that ,The three-stage motor position algorithm switching judgment and parameter compensation feedback based on the speed error include the following steps: Motor controller initialization to ensure the three-stage motor is properly calibrated and adjusted before starting operation; Perform a power-on self-test to check the normal operation of the system; The host computer sets the speed sensorless algorithm to switch the speed value and sends the control command to the motor controller; The controller synchronously collects the current speed and estimated speed of the motor; Determine the switching enable state of the position-free algorithm so as to make necessary parameter compensation and switch judgment of the position-free algorithm.

2. A novel three-stage motor starting control method according to claim 1, characterized in that: The host computer sets the algorithm as a three-level motor position-free algorithm and issues a position-free algorithm switching speed instruction.

3. A novel three-stage motor starting control method according to claim 1, characterized in that: The estimated rotation speed is obtained by a position-free algorithm.

4. A novel three-stage motor starting control method according to claim 1, characterized in that: After the position-free algorithm switching is enabled: If no position algorithm switching is enabled, then the no position algorithm switching is judged; If the no-position algorithm switching is not enabled, the no-position parameter method is used for parameter compensation.

5. A novel three-stage motor starting control method according to claim 4, characterized in that: The parameter compensation of the position-free parameter method is specifically as follows: a model reference adaptive control strategy based on parameter compensation feedback is adopted, the position-free algorithm estimation error is utilized, the system parameters are compensated, and the error is fed back to the adjustable model of the model reference adaptive control strategy.

6. A novel three-stage motor starting control method according to claim 4, characterized in that: After the position-free algorithm cuts the judgment: If the non-position algorithm is switched, the three-stage motor switches to the non-position algorithm operation; If the non-position algorithm is not switched, the current-frequency algorithm is maintained.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the control method according to any one of claims 1 to 6 are implemented.

8. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the control method according to any one of claims 1 to 6 are implemented.

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