Control circuit of hybrid stepping motor driver

Abstract

The invention discloses a control circuit of a hybrid stepping motor driver, and the control circuit comprises a control circuit, the control circuit comprises a flux linkage hysteresis controller, a torque hysteresis controller, an SVPWM module, an inverter, a stator flux linkage calculation module, a torque calculation module and a PI regulator, one side of the PI regulator is connected with one side of the torque hysteresis controller, and the other side of the PI regulator is connected with the other side of the torque hysteresis controller. The other side of the torque hysteresis controller, one side of the flux linkage hysteresis controller, one side of the stator flux linkage calculation module and one side of the torque calculation module are all connected with the SVPWM module, one side of the SVPWM module is connected with one side of the inverter, the other side of the inverter is connected with the stepping motor, and the stepping motor is connected with the stator flux linkage calculation module. The space vector pulse width modulation SVPWM and the direct torque control DTC technology are combined, the torque control characteristic of the motor is improved, the negative direct-axis current compensation field weakening control technology of the voltage outer loop is adopted, the Mamdani type fuzzy PID regulator is combined, the high dynamic response capacity of motor driving is achieved, and meanwhile torque pulsation is restrained.

Description

Technical Field

[0001] The invention relates to the technical field of control circuits, and in particular to a control circuit of a hybrid stepping motor driver. Background Art

[0002] The hybrid stepper motor driver receives the pulse signal from the control system and amplifies it to a current or voltage level sufficient to drive the stepper motor to rotate. At the same time, according to the structure and control requirements of the stepper motor, the pulse signal is distributed to each phase winding of the stepper motor to achieve precise rotation of the stepper motor. In addition, the driver can also control the direction of the pulse signal, thereby controlling the rotation direction of the stepper motor, and has protection functions such as overcurrent and overheating, which can protect the stepper motor from damage. By adjusting the frequency of the pulse signal, the hybrid stepper motor driver can also control the speed of the stepper motor to achieve the speed regulation function.

[0003] In terms of improving motor performance, hybrid stepper motor drivers can significantly improve motor performance by precisely controlling motor parameters such as current, voltage and frequency, such as reducing motor vibration and noise, achieving smoother acceleration and deceleration, and achieving higher positioning accuracy and repeatability. In addition, hybrid stepper motor drivers also have powerful programming and control functions, which can realize various complex motion controls, such as multi-axis linkage, interpolation motion, and cyclic motion of motors. These functions make hybrid stepper motors have broad application prospects in automation applications that require high precision, high speed and high reliability.

[0004] Hybrid stepper motor drivers use advanced control algorithms and energy-saving technologies to significantly reduce the energy consumption of the motor. For example, by optimizing the motor's operating mode, the motor's no-load loss and friction loss can be reduced; by precisely controlling the motor's current and voltage, the motor can be prevented from overheating and damage; and by using efficient power amplifiers and power management technologies, the motor's efficiency and reliability can be further improved.

[0005] Finally, the highly integrated and modular characteristics of hybrid stepper motor drives can greatly simplify the design of automation systems. By integrating the drive with motors, sensors and other components, a compact, efficient and reliable control system can be formed.

[0006] The vector control task of the hybrid stepper motor is to control the amplitude and phase of the stator current vector, determine the AC and DC axis currents according to the operating requirements, so that the output torque meets the control expectations. Direct torque control is a motor control method developed on the basis of a motor control theory proposed in the 1980s. DTC uses direct control of the stator flux and electromagnetic torque, and controls the output of the inverter by selecting the appropriate voltage space vector in the switch table through the hysteresis comparator. It has the advantages of torque being able to quickly respond to changes in motor parameters and good robustness.

[0007] Space vector pulse width modulation technology is a modulation technology that enables the click to obtain a circular magnetic flux trajectory. Its voltage utilization rate is about 15% higher than that of SPWM, and the switching times of the switching device can also be reduced by about 30%.

[0008] However, traditional hybrid stepper motors have the following disadvantages:

[0009] (1) At present, most moving head lights use traditional sinusoidal pulse width modulation technology to realize the rotation control of hybrid stepper motors. This technology has a simple control circuit and is easy to use, but it has the disadvantages of low bus voltage utilization and poor control stability.

[0010] (2) Due to factors such as the oversimplification of the loop controller, the inaccuracy of the stator flux observation and the discrete control voltage vector, the direct torque control system has the following shortcomings in practice: large electromagnetic torque pulsation at low speed, a large proportion of harmonics in the stator current in steady state, and low voltage utilization. Summary of the invention

[0011] The purpose of the present invention is to provide a control circuit for a hybrid stepper motor driver to solve the problem mentioned in the above background technology that most of the current moving head lamps use traditional sinusoidal pulse width modulation technology to achieve the rotation control of the hybrid stepper motor. This technology has a simple control circuit and is easy to use, but has the disadvantages of low bus voltage utilization and poor control stability. Due to the oversimplification of the hysteresis controller, the accuracy of the stator flux observation and the discrete control voltage vector, the direct torque control system has the disadvantages of large electromagnetic torque pulsation at low speed, a large proportion of harmonics in the stator current in steady state, and low voltage utilization in practice.

[0012] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a control circuit of a hybrid stepper motor driver, comprising a control circuit, wherein the control circuit comprises a flux hysteresis controller, a torque hysteresis controller, an SVPWM module, an inverter, a stator flux calculation module, a torque calculation module and a PI regulator, one side of the PI regulator is connected to one side of the torque hysteresis controller, the other side of the torque hysteresis controller and one side of the flux hysteresis controller, one side of the stator flux calculation module and one side of the torque calculation module are all connected to the SVPWM module, one side of the SVPWM module is connected to one side of the inverter, and the other side of the inverter is connected to a stepper motor.

[0013] As a preferred technical solution of the present invention, the flux hysteresis controller achieves precise control of the motor performance by adjusting the flux of the motor, optimizes the operating state of the motor by adjusting the flux hysteresis tolerance, and ensures that the motor can maintain efficient and stable operation under various working conditions.

[0014] As a preferred technical solution of the present invention, the torque hysteresis controller detects the motor stator voltage and current in real time, calculates the amplitude of the torque and flux, and compares them with the given values, and uses the obtained difference to control the amplitude of the stator flux and the angle of the vector relative to the flux, and the torque and flux regulator directly outputs the required spatial voltage vector.

[0015] As a preferred technical solution of the present invention, the SVPWM module accurately modulates the voltage space vector required to arbitrarily change the flux and torque in real time according to the size and direction of the flux and torque deviation, thereby achieving smooth regulation of the flux without being limited by the number of space voltage vectors in the switch table.

[0016] As a preferred technical solution of the present invention, the stator flux calculation module controls the excitation current and torque current of the asynchronous motor by measuring and controlling the stator current vector of the asynchronous motor according to the magnetic field orientation principle, thereby achieving the purpose of controlling the torque of the asynchronous motor.

[0017] As a preferred technical solution of the present invention, the calculation formula of the torque calculation module is T=Fxr, where: T represents the torque, F is the force acting on the object, and r is the vertical distance from the force to the axis of rotation.

[0018] As a preferred technical solution of the present invention, the PI regulator workflow is specifically as follows: S1, input signal processing: the input signal received by the PI regulator is usually the actual value measured by the sensor, which is compared with the set value to obtain a deviation signal; S2, proportional regulation: multiply the deviation signal by the proportional coefficient Kp to obtain a proportional control signal, and the size of the proportional coefficient Kp determines the strength of the proportional regulation; S3, integral regulation: integrate the deviation signal to obtain an integral control signal. The integral time constant Ti determines the speed of the integral regulation; S4, control signal synthesis: add the proportional control signal and the integral control signal to obtain the final control signal; S5, output signal processing: convert and amplify the control signal, and output it to the actuator to achieve control of the system.

[0019] Compared with the prior art, the beneficial effects of the present invention are: combining space vector pulse width modulation SVPWM and direct torque control DTC technology to improve the torque control characteristics of the motor, using the negative direct-axis current compensation weak magnetic control technology of the voltage outer loop, combined with the Mamdani type fuzzy PID regulator, to achieve high dynamic response capability of the motor drive while suppressing torque pulsation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a block diagram of a DTC control system based on SVPWM of the present invention;

[0021] Figure 2 This is a vector control structure diagram of the present invention;

[0022] Figure 3 It is a schematic diagram of the modulation and inversion circuit of the present invention;

[0023] Figure 4 It is the basic DTC block diagram of the present invention;

[0024] Figure 5 It is an S-shaped acceleration and deceleration curve diagram of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with 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 making creative work are within the scope of protection of the present invention.

[0026] See also Figure 1-5The present invention provides a control circuit of a hybrid stepper motor driver, including a control circuit, wherein the control circuit includes a flux hysteresis controller, a torque hysteresis controller, an SVPWM module, an inverter, a stator flux calculation module, a torque calculation module and a PI regulator, wherein one side of the PI regulator is connected to one side of the torque hysteresis controller, the other side of the torque hysteresis controller and one side of the flux hysteresis controller, one side of the stator flux calculation module and one side of the torque calculation module are all connected to the SVPWM module, one side of the SVPWM module is connected to one side of the inverter, and the other side of the inverter is connected to a stepper motor.

[0027] The flux hysteresis controller achieves precise control of the motor performance by adjusting the flux of the motor. By adjusting the flux hysteresis tolerance, the operating state of the motor is optimized to ensure that the motor can maintain efficient and stable operation under various working conditions.

[0028] The torque hysteresis controller detects the motor stator voltage and current in real time, calculates the amplitude of the torque and flux, and compares them with the given values. The difference is used to control the amplitude of the stator flux and the angle of the vector relative to the flux. The torque and flux regulator directly outputs the required spatial voltage vector.

[0029] The SVPWM module accurately modulates the voltage space vector required to change the flux and torque in real time according to the size and direction of the flux and torque deviation, thereby achieving smooth regulation of the flux without being limited by the number of space voltage vectors in the switch table.

[0030] The stator flux calculation module measures and controls the stator current vector of the asynchronous motor, and controls the excitation current and torque current of the asynchronous motor according to the magnetic field orientation principle, thereby achieving the purpose of controlling the torque of the asynchronous motor.

[0031] The calculation formula of the torque calculation module is T=Fxr, where: T represents the torque, F is the force acting on the object, and r is the vertical distance from the force to the axis of rotation.

[0032] The specific working process of PI regulator is as follows: S1. Input signal processing: The input signal received by PI regulator is usually the actual value measured by the sensor, which is compared with the set value to obtain the deviation signal; S2. Proportional regulation: Multiply the deviation signal by the proportional coefficient Kp to obtain the proportional control signal. The size of the proportional coefficient Kp determines the strength of the proportional regulation; S3. Integral regulation: Integrate the deviation signal to obtain the integral control signal. The integral time constant Ti determines the speed of the integral regulation; S4. Control signal synthesis: Add the proportional control signal and the integral control signal to obtain the final control signal; S5. Output signal processing: After conversion and amplification, the control signal is output to the actuator to achieve control of the system.

[0033] Embodiment 1:

[0034] In the present invention, in conjunction with the specification Figure 3 The entire three-phase hybrid stepper motor vector control system consists of a speed regulator, a current regulator, a Parker conversion and inverse conversion module. Figure 4 DTC uses direct control of the stator flux and electromagnetic torque, and selects the appropriate voltage space vector in the switch table through the hysteresis comparator to control the output of the inverter. It has the advantages of rapid response of torque to changes in motor parameters and good robustness. Figure 1 , by comparing the flux and torque of the previous control cycle with the given values, the expected voltage vector in the next control cycle is obtained from the comparison result, and then the SVPWM method is used to synthesize the expected voltage vector for control.

[0035] Embodiment 2:

[0036] In the present invention, the SVPWM module accurately modulates the voltage space vector required to change the flux and torque in real time according to the size and direction of the flux and torque deviation, thereby realizing smooth regulation of the flux without being limited by the number of space voltage vectors in the switch table. This solution can make the inverter switching frequency constant, has high DC voltage utilization, simple algorithm, low harmonic loss and noise, thereby greatly reducing the pulsation of torque and flux, and improving the performance of the system. When the stator voltage of the stepper motor reaches the limit output voltage of the inverter, if the speed is to be further increased, it is necessary to perform weak magnetic control, which is achieved by increasing the direct-axis demagnetization current, which is different from the conventional embedded permanent magnet For synchronous motors, in order to improve their operating efficiency, maximum torque current ratio control is often used. However, due to the special magnetic circuit structure of hybrid stepper motors, the difference between their AC and DC axis inductance is not large, and they are closer to hidden pole synchronous motors. This makes their MTPA trajectory almost coincide with the iq axis within the rated current range. Therefore, conventional id=0 control is used below the base speed to obtain higher operating efficiency. Compared with other weak magnetic algorithms, the negative direct axis current compensation weak magnetic control based on the voltage outer loop has the characteristics of simple system structure. The generation of its weak magnetic current command is only related to the AC and DC axis voltages and PI regulator parameters, and has nothing to do with the motor position and speed controller design.

[0037] Embodiment 3:

[0038] In the present invention, the setting of the saturation value of the PI regulator makes it easy for the algorithm to realize the mutual switching between id=0 control and weak magnetic control, and the weak magnetic effect is adjusted by reasonably setting the parameters of the PI regulator. The fuzzy control technology is used to process the parameters of the PI regulator. The input variable is the error between the feedback value and the given value, and the other input variable is the rate of change of the error. The controller is designed with multiple output terminals, and the correction values ​​of two control parameters P and I are taken as the output of the fuzzy controller. Five language subsets are defined, and the input quantity and membership function are selected as Gaussian type, and Mamdani type fuzzy reasoning is adopted. , and uses the average weighted method for defuzzification, and then passes the control quantity to the control object. The project is based on the weak magnetic control method of fuzzy PI regulator to improve the dynamic response capability of the stepper motor. During the use of the stage light, under the control of the console, new X and Y axis positioning instructions are often sent to the controller at intervals of 30-50ms. Through the motion control of the X and Y axes, it is necessary to quickly realize a variety of graphic trajectories, such as drawing circles, spirals, and chasing various effects. The parameters of the graphic trajectory, such as amplitude, speed, interval, and direction, are independently set. Therefore, it is necessary to study the high-performance motion planning algorithm of the X and Y axes.

[0039] Embodiment 4:

[0040] In the present invention, based on the dynamic model of the hybrid stepper motor, the multiple parameters of the motor are identified online in real time, the current, voltage and rotational speed of the motor are taken as input, and the electromagnetic parameters of the motor, the stator resistance Rs, dq-axis inductance, rotor flux, inertia and motion parameters position and speed are taken as output. The extended Kalman filter, model reference adaptation (MRAS) combined with the least squares algorithm technology are used to study the X-axis and Y-axis motion curve scheduling, so as to achieve fast response, no jitter and shaking of stage lights when the speed changes frequently, the uniform speed operation and the emergency stop. The most commonly used motion curves are various speed control algorithms based on the S curve. Figure 5, including polynomial models, exponential models, trigonometric function models, and the generated S-curves. These algorithms make a trade-off between motion smoothness and computational complexity. The disadvantage is that they are prone to residual vibration and time consumption at low speeds. This scheme is based on the kinematic model of stage lights and introduces 7 stages of independent kinematic constraints, position, speed and acceleration limits to obtain an asymmetric S-shaped motion curve. The speed scheduling process becomes a constrained problem handled by a nonlinear programming solver to minimize the execution time. The typical S-shaped acceleration and deceleration algorithm consists of 7 different stages, but due to the path length and start and end speed limits, it cannot be guaranteed that each speed planning has a complete 7 stages. According to the different speed curves composed of various stages, it is subdivided into 17 different types of speed planning, so in When the S-shaped acceleration and deceleration algorithm is actually applied, the type of speed planning must be determined first according to the starting speed, ending speed, path length, and acceleration restriction conditions. The 17 speed planning types are divided into three categories: only acceleration and deceleration type, no uniform speed segment type, and uniform speed segment type. The project intends to divide the path into path segments at the minimum value of the speed limit curve, and perform asymmetric S-curve speed optimization scheduling for each path segment. The optimal motion time of the motion trajectory is found through the optimization algorithm (WOA). The S-shaped speed curve based on acceleration restriction is divided into four types according to the existence of fast acceleration and deceleration. The project intends to automatically adjust the asymmetric S-curve speed acceleration and deceleration based on WOA to adapt to different arc lengths and the starting and ending speeds of the path. Based on this strategy, a smooth and time-optimal motion trajectory is obtained.

[0041] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A control circuit of a hybrid stepper motor driver, comprising a control circuit, characterized in that: The control circuit includes a flux hysteresis controller, a torque hysteresis controller, an SVPWM module, an inverter, a stator flux calculation module, a torque calculation module and a PI regulator. One side of the PI regulator is connected to one side of the torque hysteresis controller, the other side of the torque hysteresis controller and one side of the flux hysteresis controller, one side of the stator flux calculation module and one side of the torque calculation module are all connected to the SVPWM module, one side of the SVPWM module is connected to one side of the inverter, and the other side of the inverter is connected to a stepper motor.

2. The control circuit of a hybrid stepper motor driver according to claim 1, characterized in that: The flux hysteresis controller achieves precise control of the motor performance by adjusting the flux of the motor, optimizes the running state of the motor by adjusting the flux hysteresis tolerance, and ensures that the motor can maintain efficient and stable operation under various working conditions.

3. The control circuit of a hybrid stepper motor driver according to claim 1, characterized in that: The torque hysteresis controller detects the motor stator voltage and current in real time, calculates the amplitude of the torque and flux, and compares them with the given values. The obtained difference is used to control the amplitude of the stator flux and the angle of the vector relative to the flux. The torque and flux regulator directly outputs the required space voltage vector.

4. The control circuit of a hybrid stepper motor driver according to claim 1, characterized in that: The SVPWM module accurately modulates the voltage space vector required to arbitrarily change the flux and torque according to the magnitude and direction of the flux and torque deviation in real time, thereby achieving smooth regulation of the flux without being limited by the number of space voltage vectors in the switch table.

5. The control circuit of a hybrid stepping motor driver according to claim 1, characterized in that: The stator flux calculation module controls the excitation current and torque current of the asynchronous motor by measuring and controlling the stator current vector of the asynchronous motor according to the magnetic field orientation principle, thereby achieving the purpose of controlling the torque of the asynchronous motor.

6. The control circuit of a hybrid stepper motor driver according to claim 1, characterized in that: The calculation formula of the torque calculation module is T=Fxr, where: T represents the torque, F is the force acting on the object, and r is the vertical distance from the force to the rotation axis.

7. The control circuit of a hybrid stepping motor driver according to claim 1, characterized in that: The specific working process of the PI regulator is as follows: S1. Input signal processing: The input signal received by the PI regulator is usually the actual value measured by the sensor, which is compared with the set value to obtain a deviation signal; S2. Proportional regulation: Multiply the deviation signal by the proportional coefficient Kp to obtain a proportional control signal. The size of the proportional coefficient Kp determines the strength of the proportional regulation; S3. Integral regulation: Integrate the deviation signal to obtain an integral control signal. The integral time constant Ti determines the speed of the integral regulation; S4. Control signal synthesis: Add the proportional control signal and the integral control signal to obtain the final control signal; S5. Output signal processing: The control signal is converted and amplified, and then output to the actuator to realize the control of the system.

Images