Full-speed-range position-sensorless control method

Abstract

The invention belongs to the technical field of motor control, and discloses a full-speed-range position-sensorless control method, which comprises the following steps of: firstly, judging whether a difference value between an estimated rotating speed and an actual rotating speed is smaller than a certain threshold value or not; if the difference value between the estimated rotating speed and the actual rotating speed is smaller than a certain threshold value, whether the difference value between the estimated rotor position and the actual rotor position is smaller than a certain threshold value or not is judged. And when the conditions are met, the position-free algorithm is switched in. According to the method, before switching, the error between the estimated rotor position and the actual rotor position is compared, switching is allowed only when the error is smaller than a certain threshold value, and smooth switching of the position-free algorithm is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control, can be used in the field of permanent magnet synchronous motor driving, and specifically relates to a full speed range position sensorless control method. Background Art

[0002] Considering that during the starting phase, the permanent magnet synchronous motor is first started based on current-frequency control and then switched to the position-free algorithm. At the algorithm switching point, if there is a large estimated deviation of the position-free algorithm before and after the switching, the switching failure may occur when switching to the position-free algorithm.

[0003] In response to the above problems, this patent designs a method for judging the error of rotor position estimation without position sensor, and proposes a position-free algorithm switching control strategy based on speed error. The position sensor-free rotor position detection mainly includes the principle of permanent magnet synchronous motor position sensor-free implementation and the error analysis of rotor position estimation without position sensor. The relevant patent documents are retrieved as follows:

[0004] 1. Patent CN115694294A discloses a rotor position estimation method for a permanent magnet synchronous motor. The patent includes a second-order generalized integrator (SOGI) as the front stage of the in-phase filter and a signal modulation algorithm as the back stage of the in-phase filter. The in-phase filter is used to obtain a complete signal fundamental wave and introduce it into the flux observation method. At the same time, the electrical angular frequency of the motor is obtained through a frequency-locked loop module, which solves the problems of slow system control response and low observation accuracy without a position sensor in the prior art.

[0005] 2. Patent CN114785208B discloses a method for observing the rotor position error of a permanent magnet synchronous motor without position sensor control. This invention aims to solve the problem that the existing motor sensorless position observation method relies on the motor voltage equation to achieve inaccurate rotor position due to the change of motor state. It includes: under the motor load condition, the working point is scanned on the motor constant torque curve with a selected scanning step, and the MTPA working point is determined; the rotor position error θ(err) between the synchronous rotating shaft system dq and the control shaft system d*q* with position error is obtained from the minimum current vector amplitude is corresponding to the MTPA working point; the rotor position error θ(err) is used to compensate the motor rotor position.

[0006] 3. Patent CN114744925A discloses a method for measuring the rotor position of a permanent magnet synchronous motor in the full-speed domain without a position sensor. The invention discloses a method for measuring the rotor position of a permanent magnet synchronous motor in the full-speed domain without a position sensor. The method combines the rotation high-frequency signal injection method in the zero and low-speed operation stage with the back-electromotive force analytical calculation method in the medium and high-speed stage to form a full-speed domain rotor position measurement strategy. The position estimation error signals obtained by the rotation high-frequency signal injection method and the back-electromotive force analytical calculation method are normalized respectively to obtain a mixed position error signal as the position error signal in the control strategy switching interval. After passing through a PI regulator and converging to zero, the rotor position is obtained, thereby realizing position sensorless control of the permanent magnet synchronous motor within the full speed range. Summary of the invention

[0007] In order to solve the problem of switching failure when switching the position-free algorithm, the present invention provides a full-speed range position sensorless control method. Before switching, the error between the estimated rotor position and the actual rotor position is compared. When the error is less than a certain threshold, switching is allowed, thereby ensuring the smooth switching of the position-free algorithm.

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

[0009] A full speed range position sensorless control method controls the smooth switching of the position sensorless algorithm, which comprises the following steps:

[0010] The motor controller is powered on and initialized to ensure that the motor can be properly calibrated and adjusted before starting to work;

[0011] Use initial positioning and current-frequency control to start the motor from initial zero speed with load;

[0012] The speed value is set by the host computer, and the speed value is sent to the motor controller through the host computer;

[0013] The motor controller synchronously samples the current operating frequency and the estimated frequency value of the motor;

[0014] The current running frequency of the motor sampled in real time and the estimated frequency value output by the position-free algorithm are converted into the current angle value of the motor and the position-free estimated angle value respectively, wherein the initial sampling moment is taken as the zero point of the angle conversion;

[0015] The angle is modulo 0-2π, and the number of times the angle reaches 2π is used as the cycle count value. When the current angle value of the motor is equal to the angle value without position estimation, it is used as the angle count value;

[0016] By judging within the cycle count value, the positionless switching enable judgment is performed according to the angle count value, so as to perform the switching judgment of the positionless algorithm.

[0017] As a further technical solution of the present invention, a host computer is used to set the switching speed value, and the positionless switching speed value is sent down by the host computer.

[0018] As a further technical solution of the present invention, a model reference adaptive position-free control method is adopted, and a position-free switching speed value is sent down by a host computer.

[0019] As a further technical solution of the present invention, the estimated frequency is obtained through output of a position-free algorithm.

[0020] As a further technical solution of the present invention, the angle value converted from the frequency is obtained by synchronously sampling the current operating frequency of the motor and the frequency estimated by the position-free algorithm.

[0021] As a further technical solution of the present invention, after the position-free algorithm switching is enabled:

[0022] If no position algorithm switching is enabled, then the no position algorithm switching is judged;

[0023] If the position-free algorithm switching is not enabled, the current-frequency algorithm is maintained.

[0024] As a further technical solution of the present invention, after the position-free algorithm switching judgment:

[0025] If the non-position algorithm is switched, it will switch to the non-position algorithm operation;

[0026] If the non-position algorithm is not switched, the current-frequency algorithm is maintained.

[0027] 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.

[0028] A computer storage medium stores a computer program, wherein the computer program implements the steps of the control method when executed by a processor.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. It can realize the position detection function of permanent magnet synchronous motor without position sensor in the full speed range.

[0031] 2. Before switching to the position-free algorithm, the error between the estimated rotor position and the actual rotor position is compared. When it is less than a certain threshold, switching is allowed, ensuring the smooth switching of the position-free algorithm.

[0032] 3. It can solve the problem that the position-free algorithm fails to switch due to the large error in the estimated result of the position-free algorithm before and after the speed sensor-free algorithm is switched, and ensure the strategy accuracy of the model reference adaptive position-free switching algorithm under full-speed conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Reference adaptive control strategy schematics for existing models;

[0034] Figure 2 is the motor torque and rotor position error diagram;

[0035] Figure 3 It is the per-unit value diagram of motor torque and rotor position error;

[0036] Figure 4 This is a waveform diagram showing that the estimated angle is approximately equal to the actual angle frequency of the motor;

[0037] Figure 5 This is the waveform diagram when the estimated angle is about half of the actual angle frequency of the motor;

[0038] Figure 6 This is the waveform diagram when the estimated angle is about twice the actual angle frequency of the motor;

[0039] Figure 7 It is a schematic diagram of the full speed range speed sensorless control structure of the present invention;

[0040] Figure 8 This is a flow chart of the full speed range speed sensorless control of the present invention;

[0041] Fig. 9 This is a flow chart of enabling judgment of the position-free algorithm switching of the present invention;

[0042] Fig.10 The schematic diagram of a full speed range position sensorless control method of the present invention. DETAILED DESCRIPTION

[0043] 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.

[0044] In a first aspect, the present invention provides a full speed range position sensorless control method, which controls the smooth switching of the position sensorless algorithm, and comprises the following steps:

[0045] The motor controller is powered on and initialized to ensure that the motor can be properly calibrated and adjusted before starting to work;

[0046] Use initial positioning and current-frequency control to start the motor from initial zero speed with load;

[0047] The speed value is set by the host computer, and the speed value is sent to the motor controller through the host computer;

[0048] The motor controller synchronously samples the current operating frequency and the estimated frequency value of the motor;

[0049] The current running frequency of the motor sampled in real time and the estimated frequency value output by the position-free algorithm are converted into the current angle value of the motor and the position-free estimated angle value respectively, wherein the initial sampling moment is taken as the zero point of the angle conversion;

[0050] The angle is modulo 0-2π, and the number of times the angle reaches 2π is used as the cycle count value. When the current angle value of the motor is equal to the angle value without position estimation, it is used as the angle count value;

[0051] By judging within the cycle count value, the positionless switching enable judgment is performed according to the angle count value, so as to perform the switching judgment of the positionless algorithm.

[0052] like Figure 1 The principle block diagram of model reference adaptation is shown. The basic idea of ​​the model reference adaptive position sensorless method is to use the model containing the parameters to be estimated as the adjustable model, and the model without the parameters to be estimated as the reference model, and the two models have outputs with the same physical meaning. The difference between the two outputs is input into the adaptive mechanism, and the appropriate adaptive law is used to continuously adjust the parameters to be estimated estimated by the adjustable model, so that the outputs of the two models tend to be consistent. At this time, the parameter value estimated by the adjustable model is also the parameter to be estimated of the controlled object.

[0053] Using Popov stability, the adaptive law applicable to salient-pole motors can be derived as:

[0054]

[0055] After integration, the rotor position can be obtained:

[0056]

[0057] In the formula, The estimated electrical frequency is output by the model reference adaptive position-free algorithm, Outputs the estimated electrical angle for this position-free algorithm.

[0058] When switching the position-free algorithm, the error between the model reference adaptive estimated angle and the actual angle of the motor at the switching moment will cause the current to fluctuate due to the influence of the angle error, which will in turn cause the electromagnetic torque of the motor to fluctuate and affect the stability of the system. Therefore, for the model reference adaptive position sensorless algorithm, it is necessary to ensure that the angle error is within a certain range at the switching moment.

[0059] The motor load capacity and the switching point angle error are as follows: Figure 2 shown.

[0060] When there is no position algorithm switching, the motor angle error at the switching point is first judged and used as the judgment condition for control switching.

[0061] When the model reference adaptive position sensorless control algorithm is running, the angle estimated by the position algorithm fluctuates due to fluctuations in factors such as motor parameters, which will cause the frequency of the actual motor angle to be lower or higher than the frequency of the angle estimated by the position algorithm. This will cause large torque fluctuations during switching, resulting in a decrease in the system's load capacity or even unsuccessful switching.

[0062] The motor load capacity and rotor frequency error per unit value are as follows: Figure 3 shown.

[0063] When the estimated angle and the actual angle frequency of the motor are approximately equal, the switching is successful. Figure 4 shown.

[0064] When the estimated angle is about half of the actual angle frequency of the motor, the switching is unsuccessful, such as Figure 5 shown.

[0065] When the estimated angle is approximately twice the actual angle frequency of the motor, the switching is unsuccessful, such as Figure 6 shown.

[0066] Based on the above analysis, a position-free switching strategy based on angle detection is proposed to avoid the switching risk caused by the angle error before and after the switching of the model reference adaptive position-free algorithm.

[0067] By reading the real angle of the motor in one cycle and the real angle of the motor in two cycles, and comparing them with the estimated angle of the model reference adaptive algorithm, it is judged that if multiple intersections appear in one cycle, the estimated angle frequency is considered to be greater than the real motor angle frequency; if less than or equal to one intersection appears in two cycles, the estimated angle frequency is considered to be lower than the real motor angle frequency. At this time, it is set to a no-position switching scheme.

[0068] The embodiment of the present application provides a full speed range position sensorless control method, which is based on the model reference adaptive positionless control algorithm switching judgment to protect the positionless algorithm switching success. The control structure diagram is as follows: Figure 7 shown.

[0069] like Figure 8 As shown, a position-free switching control method is provided, and the method is applied to the motor position-free algorithm switching as an example for explanation, which includes the following steps:

[0070] First, connect the motor controller through the computer host computer to establish normal communication and realize real-time control of the motor. After the host computer sends the position-free algorithm switching frequency value to the motor controller, the motor controller enters the corresponding control algorithm according to the instruction and feeds back the state value of the motor to the host computer, which then displays these values ​​in real time.

[0071] The specific full speed range position sensorless control strategy is described as follows:

[0072] When the motor starts, the motor is first dragged to a certain speed through the current-frequency control method (IF control);

[0073] Among them, after the motor controller is initialized, a DC current is first passed through the motor A phase winding. At this time, after the motor controller sends a current control instruction, the motor rotor will be positioned to phase A. After a delay of 10s, the motor controller uploads the initial positioning as a completion signal to the host computer, and 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 (IF control) to drive the motor. The host computer sends current control information and 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.

[0074] Furthermore, the upper computer then issues a position-free algorithm switching frequency value instruction, at which time the speed value should be greater than the current motor running speed;

[0075] Among them, when the motor is already running at a certain speed, the motor running speed information at this time is read by the host computer. It is necessary to set a switching speed value higher than the current running speed of the motor, and input it in the host computer and then send it to the motor controller. After receiving the positionless algorithm switching speed value information sent by the host computer, the motor controller latches the value and compares it with the current motor speed information in each interrupt, wherein the current motor speed information is obtained by the current-frequency control information sent by the host computer, and the current motor speed is equal to the frequency value multiplied by 60 divided by the pole pair number, and the pole pair number value is obtained by the motor design parameters; the judgment logic is that when the current motor speed value is greater than the positionless algorithm switching speed value, the motor controller triggers the positionless algorithm operation flag and uploads the flag to the host computer. After receiving the flag information, the host computer changes the speed feedback value to the model reference adaptive positionless algorithm output speed estimate, and sends it to the motor controller.

[0076] Furthermore, the motor controller feeds back the current motor speed information to the host computer, and displays both information in the host computer;

[0077] Among them, after the position-free algorithm switching speed value is set in the host computer, the value is sent to the motor controller, the controller latches the value and sends the acceptance flag. After receiving the feedback flag, the host computer displays the current motor running speed information and the position-free algorithm switching speed value through the host computer display, where the motor running speed information is shown in formula (1).

[0078]

[0079] Where f is the motor operating frequency, and p is the motor pole pair value.

[0080] Furthermore, the motor speed control value is written into the upper computer so as to reach 95% of the motor speed at the switching point, and is sent to the motor controller, which controls the motor to increase the speed.

[0081] Among them, the host computer has received the current motor running speed information. After switching the speed information with the position-free algorithm, according to the speed value that cannot be switched, the host computer updates and issues a new speed command, which is equal to n = 0.95·n set , where n set Indicates that there is no position algorithm to switch the speed value. The frequency command is converted, where 0.95 is the preset speed information close to the switching point. Since the host computer is still working in the current-frequency mode at this time, the control information actually sent by the host computer is the frequency information. After the motor controller receives the updated frequency information, it will output the corresponding frequency current to control the motor to run to the corresponding speed, and feed back the speed information to the host computer. After receiving the speed information uploaded by the controller, the host computer will display it in real time on the host computer display.

[0082] Furthermore, the motor controller will feed back the angle information to the host computer and enter the position-free algorithm switching enable judgment link;

[0083] Among them, the motor controller has updated the output current frequency according to the new speed command sent by the host computer, and has controlled the motor speed at the new speed. After receiving the updated speed information uploaded by the controller, the host computer will trigger the position-free algorithm switching judgment method and send the current state to the controller. After receiving the flag sent by the host computer, the controller will keep the position motor speed at the current speed.

[0084] Furthermore, in the position-free algorithm switching enable judgment link, the angle value estimated by the position-free algorithm is compared with the actual angle value. The control flow chart is as follows: Fig. 9 As shown;

[0085] Among them, after the host computer triggers the positionless algorithm switching enable flag and sends it to the motor controller, the motor controller, after receiving this flag, synchronously samples the current motor operating frequency and the model reference adaptive positionless algorithm estimated frequency and uploads them to the host computer. After the host computer receives the synchronous sampling frequency uploaded by the controller, it calculates it to obtain the angle information. The method for implementing this process uses formula (2).

[0086]

[0087] In the formula, Indicates the angle value calculated according to frequency conversion, f e is the motor operating frequency value or the estimated frequency value of the speed sensorless algorithm, where the relationship between the estimated electrical angle frequency without position output and the frequency is: T s It is the motor controller operation cycle value.

[0088] The current motor operating frequency and the model reference adaptive algorithm estimated frequency are converted into angle information, and the angle is processed with a remainder of 0-2π. The angle is converted based on the current motor operating frequency, and the number of times the angle reaches 2π is used as the counting cycle, and the counting cycle is displayed in real time on the upper computer display. In the test embodiment, the motor parameter is R S=0.0015Ω, L=0.0012H, when the position-free algorithm switches the speed value at 150rpm, the angle counting cycle is 2, and the angle intersection is judged to be greater than or equal to 3 as the switching failure judgment condition, which can obtain a better switching effect. Taking this test embodiment as an example, when the angle counting cycle is 2 and the angle intersection is judged to be greater than or equal to 3 as the switching failure judgment condition, the counting cycle is set to a change value of 0-1-2-0-1-2, and the model reference adaptive algorithm estimates the frequency conversion angle value. During the above counting cycle of 0-2, the model reference adaptive algorithm estimates the frequency conversion angle value and the motor's current operating frequency conversion angle value. The number of times, that is, when When the count value is greater than or equal to 3, the host computer will send the enable flag bit of positionless switching to the controller. When the controller receives the flag bit, the motor controller will block the positionless switching judgment logic. 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 positionless algorithm switching after receiving the updated speed command information, and will not switch to the positionless algorithm operation; when the above judgment count value is less than 3, the host computer sends the enable flag bit of positionless switching to the controller. When the controller receives the flag bit, it continues to maintain the positionless switching judgment logic. When the host computer continues to send the speed increase command to the controller, the controller will enter the judgment logic of positionless algorithm switching after receiving the updated speed command information. After the conditions are met, it switches to the model reference adaptive positionless algorithm.

[0089] In this example, the angle obtained by the motor current-frequency control method is compared with the estimated angle of the model reference adaptive position-free algorithm, and the intersection of the two converted angles is recorded, stored and updated and written to the host computer. The host computer can determine whether the motor meets the switching conditions of the position-free algorithm based on the result, so as to subsequently switch the algorithm to control the motor.

[0090] A full-speed range position sensorless control strategy proposed in an embodiment of the present invention can solve the problem of failure of position algorithm switching due to large errors in position algorithm estimation results before and after the speed sensorless algorithm is switched, and ensure the strategy accuracy when the model reference adaptive positionless switching algorithm is switched under full-speed conditions.

[0091] 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.

[0092] 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.

[0093] So far, the purpose of the present invention has been achieved.

[0094] 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 full speed range position sensorless control method, characterized in that ,The control of the smooth switching of the position sensor-free algorithm includes the following steps: The motor controller is powered on and initialized to ensure that the motor can be properly calibrated and adjusted before starting to work; Use initial positioning and current-frequency control to start the motor from initial zero speed with load; The speed value is set by the host computer, and the speed value is sent to the motor controller through the host computer; The motor controller synchronously samples the current operating frequency and the estimated frequency value of the motor; The current running frequency of the motor sampled in real time and the estimated frequency value output by the position-free algorithm are converted into the current angle value of the motor and the position-free estimated angle value respectively, wherein the initial sampling moment is taken as the zero point of the angle conversion; The angle is modulo 0-2π, and the number of times the angle reaches 2π is used as the cycle count value. When the current angle value of the motor is equal to the position-free estimated angle value, it is used as the angle count value; By judging within the cycle count value, the positionless switching enable judgment is performed according to the angle count value, so as to perform the switching judgment of the positionless algorithm.

2. A full speed range position sensorless control method according to claim 1, characterized in that: The switching speed value is set by the host computer, and the position-free switching speed value is sent down by the host computer.

3. A full speed range position sensorless control method according to claim 1, characterized in that: The model reference adaptive position-free control method is adopted, and the position-free switching speed value is sent down by the upper computer.

4. A full speed range position sensorless control method according to claim 1, characterized in that: The estimated frequency is obtained through the output of the position-free algorithm.

5. The full speed range position sensorless control method according to claim 1, characterized in that: The angle value converted from the frequency is obtained by synchronously sampling the current operating frequency of the motor and the frequency estimated by the position-free algorithm.

6. A full speed range position sensorless control method according to claim 1, characterized in that: After the non-position algorithm switching is enabled: If no position algorithm switching is enabled, then the no position algorithm switching is judged; If the position-free algorithm switching is not enabled, the current-frequency algorithm is maintained.

7. A full speed range position sensorless control method according to claim 6, characterized in that: After the position-free algorithm switches to judgment: If the non-position algorithm is switched, it will switch to the non-position algorithm operation; If the non-position algorithm is not switched, the current-frequency algorithm is maintained.

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

9. 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 7 are implemented.

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