Linear active disturbance rejection control method for outer rotor brushless direct current micromotor

Abstract

This invention provides a linear active disturbance rejection control method for an external rotor brushless DC micromotor, which uses a given position angle signal. θ mref Compared with actual mechanical angle θ m The position error signal is obtained by subtracting the values; the velocity feedforward component is obtained, and it is superimposed with the first velocity setpoint component to obtain the velocity setpoint signal; the velocity setpoint signal is then compared with the actual mechanical angular velocity. ω m The difference is calculated to obtain the velocity error signal; the acceleration feedforward component is obtained, and the acceleration feedforward component is converted into a second... q After the shaft current is given a component, and then compared with the first... q The given components of the shaft current are superimposed; based on the actual mechanical angle. θ m right d Shaft voltage given signal u d and q Shaft voltage given signal u q Perform the inverse Park transform to obtain the voltage reference signal. u α , u β ; Transmit voltage command signal u α 、u β The SVPWM module is input to drive the external rotor brushless DC micromotor to output three-phase voltage. This invention can improve the motor's position control accuracy and dynamic response speed, and enhance its resistance to load disturbances.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and more specifically, to a linear active disturbance rejection control method for an external rotor brushless DC micro motor. Background Technology

[0002] As high-end equipment such as robots, precision instruments, and intelligent actuators rapidly develop towards miniaturization, high integration, and high precision, increasingly stringent performance requirements are being placed on drive actuators. As a core power component, micro-motors must possess multiple characteristics, including small size, high torque density, rapid dynamic response, and strong anti-disturbance capability. External rotor brushless DC motors, due to their compact structure, high torque density, and good operating efficiency, are increasingly widely used in these fields.

[0003] However, existing miniature external rotor brushless DC motors still have significant shortcomings in position servo control:

[0004] First, the position feedback accuracy is low. Due to the space constraints of miniaturization, it is often equipped with low-cost Hall effect or low-line-count encoders, which makes it difficult to accurately obtain the rotor angle and speed, thus limiting the accuracy of closed-loop control.

[0005] Secondly, the dynamic response is lagging. Traditional PID control parameters are fixed and cannot adapt to time-varying parameters, resulting in large overshoot, long settling time, and large tracking error during start-up, shutdown, acceleration, and deceleration.

[0006] Third, it has weak resistance to load disturbances, lacks effective estimation and compensation for sudden load changes, and exhibits significant speed fluctuations and poor position stability under disturbances. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings and deficiencies of existing technologies and provide a linear active disturbance rejection control method for external rotor brushless DC micromotors. This method can improve the position control accuracy and dynamic response speed of the motor. Simultaneously, this invention enhances the resistance to load disturbances, making the motor operation smoother and more reliable, and is suitable for high-precision micromotor control scenarios.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: a linear active disturbance rejection control method for an external rotor brushless DC micro motor, characterized in that: an encoder and a main control circuit board connected to the external rotor brushless DC micro motor are provided; a magnet is provided at the end of the output shaft of the external rotor brushless DC micro motor, and the encoder is arranged opposite to the magnet along the axial direction of the output shaft and connected to the main control circuit board.

[0009] The method involves acquiring the given position angle signal θ of the external rotor brushless DC micromotor. mrefThe encoder detects the change in the magnetic field generated by the magnet rotating synchronously with the output shaft, and acquires the actual mechanical angle θ of the external rotor brushless DC micromotor through the encoder. m and actual mechanical angular velocity ω m ;

[0010] Given the position angle signal θ mref Compared to the actual mechanical angle θ m The position error signal is obtained by subtracting the position error signal and inputting it into the position loop PI controller to generate the first speed setpoint component; the speed feedforward component is obtained and superimposed with the first speed setpoint component to obtain the speed setpoint signal;

[0011] Compare the speed command signal with the actual mechanical angular velocity ω m The difference is calculated to obtain the speed error signal, which is then input into the speed loop PI controller to generate the first q-axis current setpoint component. The acceleration feedforward component is obtained, converted into the second q-axis current setpoint component, and then superimposed with the first q-axis current setpoint component to obtain the q-axis current setpoint signal i. qref ;

[0012] The d-axis current command signal i dref With feedback d-axis current i d The difference is input to the d-axis self-disturbance current loop PI regulator to generate the d-axis voltage command signal u. d ; Set the q-axis current command signal i qref With feedback q-axis current i q The difference is input to the q-axis active disturbance rejection current loop PI regulator to generate the q-axis voltage command signal u. q ;

[0013] Based on the actual mechanical angle θ m For the d-axis voltage given signal u d and q-axis voltage given signal u q Perform the inverse Park transform to obtain the voltage reference signal u in the αβ stationary coordinate system. α u β ; Transform the voltage command signal u α u β Input the SVPWM module to generate inverter switching control signals, thereby driving the external rotor brushless DC micro motor to output three-phase voltage;

[0014] The three-phase current of the external rotor brushless DC micromotor is collected, and Clarke and Park transformations are performed sequentially to obtain the feedback q-axis current i. q and feedback d-axis current i d This forms a closed-loop control system consisting of a position loop, a speed loop, and a current loop.

[0015] Specifically, the d-axis active disturbance rejection current loop PI regulator and the q-axis active disturbance rejection current loop PI regulator are constructed in the following ways:

[0016] Establish a mathematical model of the current loop of the axis. The current loop mathematical model is a state model with the current of the axis as the state variable and the voltage of the axis as the control variable.

[0017] External load disturbances are uniformly equivalent to the total disturbance of the current loop of the axis, and the total disturbance of the current loop of the axis is introduced into the state equation of the current loop of the axis as an extended state that is different from the current state quantity of the axis, so that the mathematical model of the current loop is transformed into a current loop model with extended state.

[0018] Based on the current loop model with extended state, a linear extended state observer is constructed to estimate the total disturbance of the current loop of the axis in real time, and obtain the estimated value of the total disturbance of the current loop of the axis. According to the estimated value of the total disturbance of the current loop of the axis, disturbance feedforward compensation is introduced into the PI control law of the current loop of the axis to generate the voltage control signal of the axis after disturbance compensation.

[0019] The d-axis self-rejecting current loop PI regulator uses the d-axis current command signal i dref With feedback d-axis current i d The deviation is taken as input. The total disturbance of the d-axis current loop is estimated in real time through the d-axis extended state observer to obtain the estimated value of the total disturbance of the d-axis current loop. Based on the estimated value of the total disturbance of the d-axis current loop, the d-axis current loop disturbance feedforward compensation is introduced into the d-axis active disturbance rejection current loop PI control law to generate the d-axis voltage command signal u. d .

[0020] The q-axis active disturbance rejection current loop PI regulator uses the q-axis current command signal i qref With feedback q-axis current i q The deviation is taken as input, and the total disturbance of the q-axis current loop is estimated in real time through the q-axis extended state observer to obtain the estimated value of the total disturbance of the q-axis current loop. Based on the estimated value of the total disturbance of the q-axis current loop, q-axis current loop disturbance feedforward compensation is introduced into the q-axis active disturbance rejection current loop PI control law to generate the q-axis voltage command signal u. q .

[0021] The velocity feedforward component is derived from a given position angle signal θ. mref The result is obtained through a first-order differential circuit and is used to compensate for the dynamic lag of the position loop PI regulator, thereby improving the position tracking response speed of the external rotor brushless DC micro motor.

[0022] The acceleration feedforward component is derived from a given position angle signal θ. mref It is obtained through a second-order differential process to compensate for the inertial torque demand during the motor's acceleration and deceleration. The acceleration feedforward component is obtained from the given position angle signal θ. refIt is obtained through a second-order differential process and converted into a q-axis current feedforward quantity based on the motor's moment of inertia, torque coefficient, or equivalent proportional coefficient, which is used to compensate for the inertial torque demand during the motor's acceleration and deceleration process.

[0023] The actual mechanical angle θ m It is the coordinate transformation angle used for the inverse Park transform and the Park transform.

[0024] The SVPWM module is based on the voltage command signal u in the αβ stationary coordinate system. α u β The sector containing the space voltage vector and the duration of action of each basic voltage vector are calculated, and the corresponding PWM signal is generated to control the inverter to output three-phase AC voltage to drive the external rotor brushless DC micro motor.

[0025] The method also includes a fixed housing and a fixed base; the external rotor brushless DC micro motor is fixed inside the fixed housing; the fixed base is connected to the fixed housing; the encoder is fixed to the fixed base and is opposite to the magnet along the axial direction of the output shaft.

[0026] The magnet is fixed to the end of the output shaft with an eccentricity of less than 0.3 mm; the distance between the encoder and the magnet is less than 3 mm.

[0027] Advantages of the linear active disturbance rejection control method for external rotor brushless DC micro motors of the present invention:

[0028] (1) A magnet is set at the end of the output shaft of the external rotor brushless DC micro motor, and an encoder is set on the fixed base so that the encoder is axially opposite to the magnet. This is used to detect the actual mechanical angle and actual mechanical angular velocity of the external rotor brushless DC micro motor and to connect it to the main control circuit board.

[0029] (2) Based on the closed-loop control of position loop, speed loop and current loop, this method introduces speed feedforward, acceleration feedforward and extended state disturbance compensation to improve motor control performance.

[0030] (3) This method can realize the real-time detection of the motor output shaft angle and speed, improve the position control accuracy; improve the motor response speed through feedforward compensation, reduce dynamic tracking error; enhance the motor's anti-load disturbance capability through active disturbance rejection control, making the motor run more smoothly and reliably, and is suitable for high-precision micro motor control scenarios.

[0031] Compared with existing technologies, the present invention has the following advantages and beneficial effects: The linear active disturbance rejection control method for the external rotor brushless DC micromotor of the present invention can improve the position control accuracy of the motor and enhance the dynamic response speed of the motor. At the same time, the present invention can enhance the resistance to load disturbances, making the motor run more smoothly and reliably, and is suitable for high-precision micromotor control scenarios. Attached Figure Description

[0032] Figure 1 This is a control block diagram of the linear active disturbance rejection control method for the external rotor brushless DC micro motor of the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] Example

[0035] like Figure 1 As shown, the linear active disturbance rejection control method for the external rotor brushless DC micromotor of the present invention is as follows: A fixed housing, a fixed base, an encoder, and a main control circuit board connected to the external rotor brushless DC micromotor are provided. The external rotor brushless DC micromotor is fixed inside the fixed housing, and the fixed base is connected to the fixed housing. A magnet is placed at the end of the output shaft of the external rotor brushless DC micromotor. The encoder is fixed to the fixed base and is positioned opposite to the magnet along the axial direction of the output shaft, and is connected to the main control circuit board. To improve the stability of the detection, the magnet is fixed at the end of the output shaft with an eccentricity of less than 0.3 mm, and the distance between the encoder and the magnet is less than 3 mm.

[0036] The linear active disturbance rejection control method for this external rotor brushless DC micromotor is as follows: Obtain the given position angle signal θ of the external rotor brushless DC micromotor. mref The encoder detects the change in the magnetic field generated by the magnet rotating synchronously with the output shaft, and acquires the actual mechanical angle θ of the external rotor brushless DC micromotor through the encoder. m and actual mechanical angular velocity ω m ;

[0037] Given the position angle signal θ mref Compared to the actual mechanical angle θ m The position error signal is obtained by subtracting the position error signal and inputting it into the position loop PI controller to generate the first speed setpoint component; the speed feedforward component is obtained and superimposed with the first speed setpoint component to obtain the speed setpoint signal;

[0038] Compare the speed command signal with the actual mechanical angular velocity ω m The difference is calculated to obtain the speed error signal, which is then input into the speed loop PI controller to generate the first q-axis current setpoint component. The acceleration feedforward component is obtained, converted into the second q-axis current setpoint component, and then superimposed with the first q-axis current setpoint component to obtain the q-axis current setpoint signal i. qref ;

[0039] The d-axis current command signal i dref With feedback d-axis current i dThe difference is input to the d-axis self-disturbance current loop PI regulator to generate the d-axis voltage command signal u. d ; Set the q-axis current command signal i qref With feedback q-axis current i q The difference is input to the q-axis active disturbance rejection current loop PI regulator to generate the q-axis voltage command signal u. q ;

[0040] Based on the actual mechanical angle θ m For the d-axis voltage given signal u d and q-axis voltage given signal u q Perform the inverse Park transform to obtain the voltage reference signal u in the αβ stationary coordinate system. α u β ; Transform the voltage command signal u α u β Input the SVPWM module to generate inverter switching control signals, thereby driving the external rotor brushless DC micro motor to output three-phase voltage;

[0041] The three-phase current of the external rotor brushless DC micromotor is collected, and Clarke and Park transformations are performed sequentially to obtain the feedback q-axis current i. q and feedback d-axis current i d This forms a closed-loop control system consisting of a position loop, a speed loop, and a current loop.

[0042] Specifically, the aforementioned d-axis active disturbance rejection current loop PI regulator and q-axis active disturbance rejection current loop PI regulator are constructed in the following ways:

[0043] Establish a mathematical model of the current loop of the axis. The current loop mathematical model is a state model with the current of the axis as the state variable and the voltage of the axis as the control variable.

[0044] External load disturbances are uniformly equivalent to the total disturbance of the current loop of the axis, and the total disturbance of the current loop of the axis is introduced into the state equation of the current loop of the axis as an extended state that is different from the current state quantity of the axis, so that the mathematical model of the current loop is transformed into a current loop model with extended state.

[0045] Based on the current loop model with extended state, a linear extended state observer is constructed to estimate the total disturbance of the current loop of the axis in real time, and obtain the estimated value of the total disturbance of the current loop of the axis. According to the estimated value of the total disturbance of the current loop of the axis, disturbance feedforward compensation is introduced into the PI control law of the current loop of the axis to generate the voltage control signal of the axis after disturbance compensation.

[0046] Specifically, the d-axis self-disruption current loop PI regulator uses the d-axis current command signal i dref With feedback d-axis current i dThe deviation is taken as input. The total disturbance of the d-axis current loop is estimated in real time through the d-axis extended state observer to obtain the estimated value of the total disturbance of the d-axis current loop. Based on the estimated value of the total disturbance of the d-axis current loop, the d-axis current loop disturbance feedforward compensation is introduced into the d-axis active disturbance rejection current loop PI control law to generate the d-axis voltage command signal u. d .

[0047] Specifically, the q-axis active disturbance rejection current loop PI regulator uses the q-axis current command signal i qref With feedback q-axis current i q The deviation is taken as input, and the total disturbance of the q-axis current loop is estimated in real time through the q-axis extended state observer to obtain the estimated value of the total disturbance of the q-axis current loop. Based on the estimated value of the total disturbance of the q-axis current loop, q-axis current loop disturbance feedforward compensation is introduced into the q-axis active disturbance rejection current loop PI control law to generate the q-axis voltage command signal u. q .

[0048] In addition, the velocity feedforward component is derived from the given position angle signal θ. mref The result is obtained through a first-order differential circuit and is used to compensate for the dynamic lag of the position loop PI regulator, thereby improving the position tracking response speed of the external rotor brushless DC micro motor.

[0049] The acceleration feedforward component is given by the position angle signal θ. mref It is obtained through a second-order differential process to compensate for the inertial torque demand during the motor's acceleration and deceleration. The acceleration feedforward component is obtained from the given position angle signal θ. ref It is obtained through a second-order differential process and converted into a q-axis current feedforward quantity based on the motor's moment of inertia, torque coefficient, or equivalent proportional coefficient, which is used to compensate for the inertial torque demand during the motor's acceleration and deceleration process.

[0050] The actual mechanical angle θ of this invention m It serves as the coordinate transformation angle for both the inverse Park transform and the Park transform. The SVPWM module, however, uses the voltage input signal u in the αβ stationary coordinate system. α u β The sector containing the space voltage vector and the duration of action of each basic voltage vector are calculated, and the corresponding PWM signal is generated to control the inverter to output three-phase AC voltage to drive the external rotor brushless DC micro motor.

[0051] Advantages of the linear active disturbance rejection control method for external rotor brushless DC micro motors of the present invention:

[0052] (1) A magnet is set at the end of the output shaft of the external rotor brushless DC micro motor, and an encoder is set on the fixed base so that the encoder is axially opposite to the magnet. This is used to detect the actual mechanical angle and actual mechanical angular velocity of the external rotor brushless DC micro motor and to connect it to the main control circuit board.

[0053] (2) Based on the closed-loop control of position loop, speed loop and current loop, this method introduces speed feedforward, acceleration feedforward and extended state disturbance compensation to improve motor control performance.

[0054] (3) This method can realize the real-time detection of the motor output shaft angle and speed, improve the position control accuracy; improve the motor response speed through feedforward compensation, reduce dynamic tracking error; enhance the motor's anti-load disturbance capability through active disturbance rejection control, making the motor run more smoothly and reliably, and is suitable for high-precision micro motor control scenarios.

[0055] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A linear active disturbance rejection control method for an external rotor brushless DC micro motor, characterized in that: An encoder and a main control circuit board connected to the external rotor brushless DC micro motor are set up; a magnet is set at the end of the output shaft of the external rotor brushless DC micro motor, and the encoder is set opposite to the magnet along the axial direction of the output shaft and connected to the main control circuit board. The method involves acquiring the given position angle signal θ of the external rotor brushless DC micromotor. mref The encoder detects the change in the magnetic field generated by the magnet rotating synchronously with the output shaft, and acquires the actual mechanical angle θ of the external rotor brushless DC micromotor through the encoder. m and actual mechanical angular velocity ω m ; Given the position angle signal θ mref Compared to the actual mechanical angle θ m The difference is calculated to obtain the position error signal, which is then input into the position loop PI controller to generate the first velocity setpoint component. The velocity feedforward component is obtained, and the velocity feedforward component is superimposed with the first velocity setpoint component to obtain the velocity setpoint signal; Compare the speed command signal with the actual mechanical angular velocity ω m The difference is calculated to obtain the speed error signal, which is then input into the speed loop PI regulator to generate the first q-axis current setpoint component. The acceleration feedforward component is obtained, converted into a second q-axis current command component, and then superimposed with the first q-axis current command component to obtain the q-axis current command signal i. qref ; The d-axis current command signal i dref With feedback d-axis current i d The difference is input to the d-axis self-disturbance current loop PI regulator to generate the d-axis voltage command signal u. d ; Set the q-axis current command signal i qref With feedback q-axis current i q The difference is input to the q-axis active disturbance rejection current loop PI regulator to generate the q-axis voltage command signal u. q ; Based on the actual mechanical angle θ m For the d-axis voltage given signal u d and q-axis voltage given signal u q Perform the inverse Park transform to obtain the voltage reference signal u in the αβ stationary coordinate system. α u β ; Transform the voltage command signal u α u β Input the SVPWM module to generate inverter switching control signals, thereby driving the external rotor brushless DC micro motor to output three-phase voltage; The three-phase current of the external rotor brushless DC micromotor is collected, and Clarke and Park transformations are performed sequentially to obtain the feedback q-axis current i. q and feedback d-axis current i d This forms a closed-loop control system consisting of a position loop, a speed loop, and a current loop.

2. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The d-axis active disturbance rejection current loop PI regulator and the q-axis active disturbance rejection current loop PI regulator are constructed in the following ways: Establish a mathematical model of the current loop of the axis. The current loop mathematical model is a state model with the current of the axis as the state variable and the voltage of the axis as the control variable. External load disturbances are uniformly equivalent to the total disturbance of the current loop of the axis, and the total disturbance of the current loop of the axis is introduced into the state equation of the current loop of the axis as an extended state that is different from the current state quantity of the axis, so that the mathematical model of the current loop is transformed into a current loop model with extended state. Based on the current loop model with extended state, a linear extended state observer is constructed to estimate the total disturbance of the current loop on this axis in real time, and obtain the estimated value of the total disturbance of the current loop on this axis. Based on the estimated total disturbance of the current loop of the shaft, disturbance feedforward compensation is introduced into the PI control law of the current loop of the shaft to generate the voltage control signal of the shaft after disturbance compensation.

3. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 2, characterized in that: The d-axis self-rejecting current loop PI regulator uses the d-axis current command signal i dref With feedback d-axis current i d The deviation is taken as input. The total disturbance of the d-axis current loop is estimated in real time through the d-axis extended state observer to obtain the estimated value of the total disturbance of the d-axis current loop. Based on the estimated value of the total disturbance of the d-axis current loop, the d-axis current loop disturbance feedforward compensation is introduced into the d-axis active disturbance rejection current loop PI control law to generate the d-axis voltage command signal u. d .

4. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 2, characterized in that: The q-axis active disturbance rejection current loop PI regulator uses the q-axis current command signal i qref With feedback q-axis current i q The deviation is taken as input, and the total disturbance of the q-axis current loop is estimated in real time through the q-axis extended state observer to obtain the estimated value of the total disturbance of the q-axis current loop. Based on the estimated value of the total disturbance of the q-axis current loop, q-axis current loop disturbance feedforward compensation is introduced into the q-axis active disturbance rejection current loop PI control law to generate the q-axis voltage command signal u. q .

5. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The velocity feedforward component is derived from a given position angle signal θ. mref The result is obtained through a first-order differential circuit and is used to compensate for the dynamic lag of the position loop PI regulator, thereby improving the position tracking response speed of the external rotor brushless DC micro motor.

6. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The acceleration feedforward component is derived from a given position angle signal θ. mref It is obtained through a second-order differential process to compensate for the inertial torque demand during the acceleration and deceleration of the motor.

7. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The actual mechanical angle θ m It is the coordinate transformation angle used for the inverse Park transform and the Park transform.

8. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The SVPWM module is based on the voltage command signal u in the αβ stationary coordinate system. α u β The sector containing the space voltage vector and the duration of action of each basic voltage vector are calculated, and the corresponding PWM signal is generated to control the inverter to output three-phase AC voltage to drive the external rotor brushless DC micro motor.

9. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The method also includes a fixed housing and a fixed base; the external rotor brushless DC micro motor is fixed inside the fixed housing; the fixed base is connected to the fixed housing; the encoder is fixed to the fixed base and is opposite to the magnet along the axial direction of the output shaft.

10. The linear active disturbance rejection control method for an external rotor brushless DC micromotor according to claim 1, characterized in that: The magnet is fixed to the end of the output shaft with an eccentricity of less than 0.3 mm; the distance between the encoder and the magnet is less than 3 mm.

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