EGR valve intelligent motor control method and device

Abstract

The invention discloses an EGR valve intelligent motor control method and device, and the method comprises the steps: carrying out the batch collection of position signals of a rotor through a 3D Hall sensor, and converting the position signal data into electric signal data; edge judgment is carried out on each group of electric signal data, abnormal points are removed, effective data are reserved, and average sampling is carried out on the effective data to obtain multiple groups of effective data; the number of turns of the multiple sets of effective data is judged; calculating the real-time absolute angle of the rotor according to the number of turns and the real-time in-circle angle of the rotor obtained by the 3D Hall sensor; according to the real-time absolute angle, a foc algorithm is adopted to obtain a corresponding three-phase voltage value; and outputting a three-phase voltage through the PWM driving signal to control the motor. A 3D Hall mode is adopted, a program for timely and efficiently processing and recognizing error signals is added, the position control precision is high, the electrifying sequence of the three-phase motor is controlled through a special algorithm, motor reversing is smoother, thrust is more stable, and large force value fluctuation cannot occur.

Description

Technical Field

[0001] The present invention relates to the field of motor technology, and in particular to an EGR valve intelligent motor control method and device. Background Art

[0002] In the development of motor technology, brushless DC motors occupy a key position. From the early brushed DC motors to the widely used brushless DC motors today, technological progress has continuously promoted the development of various fields. Traditional brushed DC motors will produce friction, sparks and electromagnetic interference during operation due to the presence of brushes and commutators, which limits their application in some occasions with high requirements for reliability and stability. With the continuous development of electronic technology, control theory and power semiconductor devices, brushless DC motors came into being, bringing major changes to the motor field.

[0003] The existing industry solution is to use three Hall switches to sense the position of the brushless motor rotor and use the six-step commutation method to control the power-on sequence of the three-phase motor. Finally, the motor control circuit board sends the position information of the motor rotor and processes it into a CAN signal to communicate with the on-board MCU. For existing technologies, please refer to the technical solution disclosed by Mitsubishi Corporation: JPWO2012131750A1. Mitsubishi's solution uses the Hall switch commutation method, and the minimum commutation angle is 10°, which means that the minimum displacement distance converted to the position of the motor screw is 0.22mm when the pitch is 2 and the lead is 4. The accuracy can no longer meet the control requirements of some EGR valves. Moreover, the six-step commutation used has only six power-on states, and the torque fluctuation is very obvious.

[0004] The information disclosed in the above background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] In view of the above-mentioned existing defects, the purpose of the present invention is to provide an EGR valve intelligent motor control method and device, which adopts a 3D Hall form, adds a program for timely and efficient processing and identification of error signals, has high position control accuracy, and uses a special algorithm to control the power-on sequence of the three-phase motor. The motor commutation is smoother, the thrust is more stable, and there will be no large force fluctuations.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An EGR valve intelligent motor control method comprises the following steps:

[0008] S1: Use 3D Hall sensors to batch collect rotor position signals, where the position signal data is converted into electrical signal data;

[0009] S2: Perform edge judgment on each set of electrical signal data, remove abnormal points, retain valid data, and average sample the valid data to obtain multiple sets of valid data;

[0010] S3: Determine the number of circles for multiple sets of valid data;

[0011] S4: Calculate the real-time absolute angle of the rotor according to the number of turns and the real-time in-turn angle of the rotor obtained by the 3D Hall sensor;

[0012] S5: Using the foc algorithm according to the real-time absolute angle, obtain the corresponding three-phase voltage values;

[0013] S6: Outputting three-phase voltage via PWM drive signal to control the motor.

[0014] Furthermore, S1 uses a 3D Hall sensor to collect the rotor position signal in batches. Specifically, when the motor is powered on, the Hall sensor triggers the chip ADC to collect a group of data on a single channel. Each group of data is sampled X times, and the sampling time for each time is T.

[0015] Furthermore, in S2, edge judgment is performed on each group of electrical signal data, abnormal points are eliminated, and valid data is retained. Specifically, the edge limit value of the batch of electrical signal data is obtained, and the maximum value is subtracted from the minimum value. If the value is less than the set safety value, the group of data is retained, otherwise, it is not retained.

[0016] Furthermore, in S2, the valid data is sampled on average; specifically:

[0017] Effective Value=(Data1+Data2+Data3+Data4+……+DataX) / X

[0018] Furthermore, S3 determines the number of circles for multiple sets of valid data, specifically:

[0019] S301: Determine whether Effective Value2 minus Effective Value1 is greater than a preset threshold. If so, record a lap and proceed to step 2. If less than or equal to the threshold, do not record a lap.

[0020] S302: If the difference is positive, then N count Add one circle, and the difference is negative, then N count Minus one circle;

[0021] Among them, Effective Value2 is the post-sampling value, and Effective Value1 is the pre-sampling value.

[0022] Furthermore, in S4, the real-time absolute angle of the rotor is calculated according to the real-time in-circle angle of the rotor obtained by the circle counting and the 3D Hall sensor; specifically:

[0023] θ R =N count ×360°+θ c

[0024] θ R is the real-time absolute angle of the rotor, θ c is the real-time internal angle of the rotor, N count To record the number of laps.

[0025] Furthermore, in S5, the foc algorithm is used according to the real-time absolute angle to obtain the corresponding three-phase voltage value; specifically, firstly, the current component of the rotating coordinate system is converted into the current component I in the two-phase stationary coordinate system by inverse Park transformation. α ,I β , the calculation formula is as follows:

[0026] I α =I d cosθ-I q sinθ

[0027] I β =I q cosθ+I d sinθ

[0028] Among them, I q is the current component perpendicular to the magnetic field direction, I d is the current component aligned with the magnetic field direction, obtained by setting a known required torque;

[0029] The α-β current components are then converted into three-phase current I by inverse Clarke transformation a ,I b ,I c , the calculation formula is as follows:

[0030] I a =I α

[0031]

[0032] Finally, multiply it by the resistance of the motor, which equals the voltage value that needs to be added to the three phases.

[0033] The present invention also discloses an EGR valve intelligent motor control device, which adopts the above-mentioned EGR valve intelligent motor control method, including: a 3D Hall sensor, a commutation magnet, a motor MCU, and an engine ECU. The commutation magnet is arranged on the driving shaft of the motor rotor. The 3D Hall sensor is used to obtain the current in-circle angle of the rotor according to the magnetic field strength of the commutation magnet at different angles of 0-360°, and is used to batch collect the position signals of the rotor and convert the position signal data into electrical signal data; the motor MCU is also used to perform edge judgment according to the electrical signal data, eliminate abnormal points, retain valid data, and average sample the valid data, and judge the number of revolutions of the rotor according to the processed data; the engine ECU is used to send a control instruction of the opening degree of the control valve to the motor MCU through CAN communication, and the motor MCU calculates the required three-phase voltage according to the current in-circle angle of the rotor and the number of revolutions information, controls the rotation of the rotor, and thus controls the opening degree of the valve.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention adopts the form of 3D Hall to sense the position of the brushless motor rotor, and through the use of a pair of magnetic poles to generate a magnetic field, the corresponding voltage value is output through the 3D Hall, and the number of revolutions is recorded through MCU processing, so as to determine the position of the motor screw, with high accuracy and resolution. The position sensor will continuously feed back the rotor position signal to the motor control system. When this solution is used to convert the position of the motor screw into a pitch of 2 and a lead of 4, the rotation angle can be subdivided into 0.087°, and the minimum controlled displacement distance is 0.00193mm, which is much more accurate than the original solution.

[0036] 2. The present invention converts the 3D Hall position signal into an electrical signal, and uses the MCU ADC module for signal acquisition. Among them, due to the physical property that the voltage of the capacitor module cannot change suddenly. When the Hall signal rotates one circle, the electrical signal switches from 5V to 0V. When the ADC module collects the electrical signal, it is easy to collect wrong data, especially when the motor is in working motion. Once the signal acquisition error occurs, it will cause great damage to the entire motor motion system. It will lead to inaccurate position control and motor circle counting errors. The present invention adopts a software algorithm to timely and efficiently process and identify the electrical signals collected by the ADC at high speed, and eliminate the signals with sampling errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A step diagram of an EGR valve intelligent motor control method of the present invention;

[0038] Figure 2 This is the judgment logic diagram of step S2 of the present invention;

[0039] Figure 3 The voltage variation diagram of the Hall signal of the present invention after rotating four times;

[0040] Figure 4 This is a schematic diagram of the EGR valve intelligent motor of the present invention.

[0041] Figure 5 This is a schematic diagram of the EGR valve intelligent motor rotor of the present invention.

[0042] In the figure, 1-3D Hall sensor; 2-commutation magnet; 3-rotor; 4-screw. DETAILED DESCRIPTION

[0043] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the embodiments and accompanying drawings. In the description of this embodiment, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0044] Example 1

[0045] like Figure 1-3 As shown, an EGR valve intelligent motor control method of this embodiment is mainly used in the EGR valve control of a brushless motor. This method mainly uses a 3D Hall sensor, which can detect the magnetic field strength of the rotor at different angles x, y, and z from 0 to 360°. Therefore, the rotor angle can be calculated by reading the magnetic field strength of x, y, and z of the rotor's current state. It includes the following steps:

[0046] S1: Use 3D Hall sensors to batch collect the rotor position signals, where the position signal data is converted into electrical signal data. Specifically, when the motor is powered on, the Hall sensor triggers the chip ADC to collect a group of data on a single channel. Each group of data is sampled 5 times, and each sampling time is 24μs. The purpose of batch collecting signals is for machine circle learning.

[0047] S2: Perform edge judgment on each set of electrical signal data, remove abnormal points, retain valid data, and average sample the valid data to obtain multiple sets of valid data.

[0048] Compare the difference of a group of data before and after. If there is a jump, there will be a continuously changing value. Obtain the edge limit value of the batch of data. For example, the normal value collected is: "4.97V 4.97V 4.97V 4.98V 4.98V", and make a safety edge judgment, that is, subtract the maximum and minimum values. If the value is less than the set safety value (0.12V), keep this group of data, otherwise, discard it. Because the falling edge time is short, about 40us, ADC sampling can only collect data from one point in such a short time. If the motor is in the jump position, if it is an abnormal value, it is: "4.97V 4.97V 4.97V 3V 0V". If the difference between the two extremes is greater than the safety value, discard the batch of data, otherwise, keep the data.

[0049] like Figure 3 As shown, there will be a voltage jump every time the motor rotates one circle. The motor will jump from 0V to 5V or from 5V to 0V during one rotation. It can be found that an obvious difference between the normal acquisition point and the error acquisition point is that the error acquisition point will be located on the falling edge, which is caused by the physical characteristics of the filter capacitor. Because the falling edge time is short, about 40us, there will be a group of sampling points, and some points will be located on the falling edge, resulting in errors in the overall data. Therefore, it is necessary to filter the retained data and perform average sampling, as shown in the following formula to obtain more stable data.

[0050] Effective Value=(Data1+Data2+Data3+Data4+Data5) / 5

[0051] The data obtained through the above processing is more stable. The signal processing logic is as follows: Figure 2 shown.

[0052] S3: Determine the number of circles for multiple sets of valid data;

[0053] Because the sensor can only output 0 to 5V, the number of turns cannot be processed. Therefore, the circle counting algorithm is optimized. The following measures are taken to determine whether the number of turns is increased or decreased by 1 based on the valid sampling values ​​before and after the two times, as shown in the following formula.

[0054] |Effective Value2-Effective Value1|>Judgment threshold (0.85*5V)

[0055] If the difference is a positive number, count increases by one circle, and if the difference is a negative number, count decreases by one circle. Effective Value2 is the latest sampling value, and Effective Value1 is the previous sampling value.

[0056] S4: Calculate the real-time absolute angle of the rotor according to the number of turns and the real-time in-turn angle of the rotor obtained by the 3D Hall sensor;

[0057] The specific formula is:

[0058] θ R =N count ×360°+θ c

[0059] θ R is the real-time absolute angle of the rotor, θ c is the real-time internal angle of the rotor, N count To record the number of laps.

[0060] S5: Using the foc algorithm according to the real-time absolute angle, obtain the corresponding three-phase voltage values;

[0061] The purpose of the FOC algorithm is to accurately control the torque, speed and position of the motor through real-time angle. By measuring the rotor angle in real time, FOC can adjust the current in real time to ensure that the performance and response of the motor meet the target requirements.

[0062] Furthermore, after knowing the rotor angle, it is necessary to energize the three-phase electricity of the brushless motor. The stator needs to generate a magnetic field to always pull the permanent magnet magnetic field of the rotor for switching. The original scheme uses six-step commutation with only six power-on states, and the torque fluctuation is very obvious. On the contrary, the new scheme uses the foc algorithm to transform the angles of the rotor and stator through Park inverse transformation, as shown in the following formula 34, to obtain the values ​​of Iα and Iβ, and then through Clark inverse transformation, it is converted into the values ​​required by the MCU to control the three-phase motor Ia, Ib, and IC, and the voltage value of the three-phase motor PWM through the MCU control input of the motor is obtained, which is the key to the stable output thrust of the motor.

[0063] I α =I d cosθ-I q sinθ

[0064] I β =I q cosθ+I d sinθ

[0065] Among them, I q is the current component perpendicular to the magnetic field direction, I d is the current component aligned with the magnetic field direction, obtained by setting a known required torque;

[0066] I a =I α

[0067]

[0068] Assuming that θ is 30° (the electrical angle of motor feedback), iq and id are the required torques. In the embodiment, iq=1, id=0. Substituting the formula into the formula, we can get Iα=-1 / 2, Iβ=√3 / 2. Substituting the obtained Iα and Iβ into the formula, we can get Ia=-1 / 2, Ib=1 / 2, Ic=-1; multiplying by the resistance of the motor, it is equal to the voltage value that needs to be added to the three items.

[0069] S6: Output three-phase voltage to control the motor through PWM drive signal.

[0070] This intelligent control method for the motor system based on brushless motors, FOC algorithms and 3D Hall sensors has the advantages of high-precision control, high efficiency and stable operation. Through 3D Hall electrical signal processing, it optimizes effective data, better realizes circle counting logic judgment, ensures precise control, real-time angle feedback and optimized current distribution, achieves smooth torque output and fast dynamic response, and can accurately control the target angle and push rod position in the precise adjustment scenario of the EGR valve, meeting the needs of precise control and complex control.

[0071] Example 2

[0072] This embodiment is based on the embodiment 1, and provides an EGR valve intelligent motor control device, such as Figure 4-5 As shown, it mainly includes: 3D Hall sensor 1, commutation magnet 2, motor MCU, engine ECU, motor rotor 3, and screw 4. A pair of magnetic poles of the commutation magnet 2 are arranged in a circular shape on the driving shaft of the motor rotor 3. The 3D Hall sensor 1 is arranged on the motor housing, and is used to obtain the current inner circle angle of the motor rotor 3 according to the magnetic field strength of the commutation magnet at different angles of 20-360°, and to batch collect the position signal of the motor rotor 3, and convert the position signal data into electrical signal data; the motor MCU is also used to perform edge judgment based on the electrical signal data, eliminate abnormal points, retain valid data, and averagely sample the valid data, and judge the number of revolutions of the rotor based on the processed data; the engine ECU is used to send a control instruction of the opening degree of the control valve to the motor MCU through CAN communication, and the motor MCU calculates the required three-phase voltage based on the current inner circle angle and the number of revolutions of the rotor, and controls the rotation of the rotor, thereby controlling the opening degree of the valve.

[0073] When the stroke of screw 5 needs to be adjusted, the required target stroke d of motor screw 5 is first obtained from the engine ECU, and the motor MCU calculates the required target angle of the rotor; then the real-time absolute angle of the rotor is obtained through the 3D Hall sensor; the difference between the required target angle and the current rotor angle is calculated; according to the angle error, the PID algorithm is used to control the movement of the motor so that the rotor reaches the required target angle, thereby controlling the stroke of the screw and then controlling the opening degree of the motor control valve.

[0074] Taking a motor with a screw pitch of 2mm and a lead of 4mm as an example, the mechanical displacement corresponding to one rotation of the motor is 8mm. The extension distance of the push rod is controlled by a PID algorithm, so that the motor's response speed is extremely fast and can be controlled within 200ms.

[0075] Although the present invention has been described in detail above with specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. An EGR valve intelligent motor control method, characterized in that: The steps include: S1: Use 3D Hall sensors to batch collect rotor position signals, where the position signal data is converted into electrical signal data; S2: Perform edge judgment on each set of electrical signal data, remove abnormal points, retain valid data, and average sample the valid data to obtain multiple sets of valid data; S3: Determine the number of circles for multiple sets of valid data; S4: Calculate the real-time absolute angle of the rotor according to the number of turns and the real-time in-turn angle of the rotor obtained by the 3D Hall sensor; S5: Using the foc algorithm according to the real-time absolute angle, obtain the corresponding three-phase voltage values; S6: Outputting three-phase voltage via PWM drive signal to control the motor.

2. The EGR valve intelligent motor control method according to claim 1, characterized in that: In S1, 3D Hall sensors are used to collect the rotor position signals in batches, specifically: When the motor is powered on, the Hall sensor triggers the chip ADC to collect a set of data on a single channel. Each set of data is sampled X times, and the sampling time for each time is T.

3. The EGR valve intelligent motor control method according to claim 1, characterized in that: In S2, each set of electrical signal data is subjected to edge judgment, abnormal points are eliminated, and valid data is retained. Specifically: Obtain the edge limit value for the batch of electrical signal data, subtract the maximum value from the minimum value, and if the value is less than the set safety value, retain the group of data, otherwise, do not retain it.

4. The EGR valve intelligent motor control method according to claim 1, characterized in that: In S2, the valid data is sampled on average; specifically: Effective Value=(Data1+Data2+Data3+Data4+……+DataX) / X.

5. The EGR valve intelligent motor control method according to claim 1, characterized in that: In S3, the number of circles of multiple sets of valid data is determined, specifically: S301: Determine whether Effective Value2 minus Effective Value1 is greater than a preset threshold. If so, record a lap and proceed to step 2. If less than or equal to the threshold, do not record a lap. S302: If the difference is positive, then N count Add one circle, and the difference is negative, then N count Minus one circle; Among them, Effective Value2 is the post-sampling value, and Effective Value1 is the pre-sampling value.

6. The EGR valve intelligent motor control method according to claim 1, characterized in that: In S4, the real-time absolute angle of the rotor is calculated based on the real-time in-circle angle of the rotor obtained by the circle counting and the 3D Hall sensor; specifically: i R =N count ×360°+θ c ; θ R is the real-time absolute angle of the rotor, θ c is the real-time internal angle of the rotor, N count To record the number of laps.

7. The EGR valve intelligent motor control method according to claim 1, characterized in that: In S5, the foc algorithm is used according to the real-time absolute angle to obtain the corresponding three-phase voltage values; specifically: First, the current component of the rotating coordinate system is converted into the current component I in the two-phase stationary coordinate system through the inverse Park transformation. α ,I β , the calculation formula is as follows: I α =I d cosθ-I q sinθ; I β =I q cosθ+I d sinθ; Among them, I q is the current component perpendicular to the magnetic field direction, I d is the current component aligned with the magnetic field direction, obtained by setting a known required torque; The α-β current components are then converted into three-phase current I by inverse Clarke transformation a ,I b ,I c , the calculation formula is as follows: I a =I α ; Finally, multiply it by the resistance of the motor, which equals the voltage value that needs to be added to the three phases.

8. An EGR valve intelligent motor control device, which adopts the EGR valve intelligent motor control method according to any one of claims 1 to 6, characterized in that: include: 3D Hall sensor, commutation magnet, motor MCU, engine ECU, the commutation magnet is arranged on the driving shaft of the motor rotor, The 3D Hall sensor is used to obtain the current inner angle of the rotor by detecting the magnetic field strength of the commutation magnet at different angles of 0-360°, and to collect the rotor position signal in batches and convert the position signal data into electrical signal data; The motor MCU is also used to make edge determinations based on the electrical signal data, remove abnormal points, retain valid data, perform average sampling on the valid data, and determine the number of revolutions of the rotor based on the processed data; The engine ECU is used to send control instructions for the opening degree of the control valve to the motor MCU through CAN communication. The motor MCU calculates the required three-phase voltage based on the current in-circle angle of the rotor and the number of revolutions to control the rotation of the rotor, thereby controlling the opening degree of the valve.

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