CN119872270B - Ramp auxiliary method and system based on motor control position loop control - Google Patents

Abstract

The present invention provides a slope assist method and system based on motor control position loop control, comprising the following steps: step S1, when a preset anti-slope start condition is met, the vehicle enters an anti-slope mode; step S2, performing motor control position loop control, inputting a target position and an actual position, and outputting a target speed through position loop proportional control; step S3, performing motor control speed loop control, inputting a target speed and an actual speed, and outputting a q-axis target current and a d-axis target current through proportional differential control, with the d-axis target current set to 0; the actual speed is the actual speed of the permanent magnet synchronous motor; in step S4, performing motor control current loop control, outputting a three-phase voltage; and in step S5, performing motor control, inputting the three-phase voltage output in step S4, and driving the permanent magnet synchronous motor. The present invention can improve control accuracy and anti-interference capability, and can reduce or even eliminate hysteresis distance.

Description

Ramp auxiliary method and system based on motor control position loop control

Technical Field

The invention relates to the field of automobiles, in particular to a ramp auxiliary method and system based on motor control position loop control.

Background

With the rapid development of new energy automobile industry, the electric drive technology is widely applied in the automobile field due to the advantages of high efficiency, environmental protection and the like. However, during the parking or starting process of the vehicle, a sliding phenomenon is easy to occur due to the action of gravity, and serious traffic safety hazards can be caused particularly when the vehicle exists on a wet road surface, a steep road section or behind the steep road section.

The existing anti-slip technology is mainly based on the torque quick response characteristic of a driving motor, a rotational speed ring and current ring Proportional Integral (PI) control strategy is adopted in motor control software, the state of a vehicle is monitored in real time, braking torque is reversely applied when a slip trend is detected to balance the vehicle hysteresis torque, PI parameter calibration of the rotational speed ring and the current ring is complex and lengthy, improper parameter setting easily causes control hysteresis or excessive, the hysteresis distance is too long and even is out of control, and the hysteresis distance is longer when the vehicle is fully loaded.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a ramp auxiliary method and a ramp auxiliary system based on motor control position ring control, which aim to improve control precision, anti-interference capability and reduce or even eliminate hysteresis distance.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

according to a first aspect of the present invention, there is provided a ramp assist method based on motor control position loop control, comprising the steps of:

step S1, when a preset anti-slip starting condition is met, the vehicle enters an anti-slip mode;

Step S2, motor control position loop control is carried out, a target position and an actual position are input, and target speed is output through position loop proportional control, wherein the actual position is the actual rotor position of the permanent magnet synchronous motor read by an encoder;

Step S3, motor control speed loop control is carried out, target speed and actual speed are input, q-axis target current and d-axis target current are output through active disturbance rejection control, and the d-axis target current is set to be 0, wherein the actual speed is the actual rotating speed of the permanent magnet synchronous motor;

In step S4, motor control current loop control is carried out, q-axis actual current and d-axis actual current are obtained and input according to three-phase current of a permanent magnet synchronous motor, q-axis target current and d-axis target current are input, dynamic decoupling is realized through zero pole cancellation through complex vector PI control, q-axis voltage and d-axis voltage are output, alpha-axis voltage and beta-axis voltage in a two-phase static coordinate system are output through inverse Park operation, and voltage signals are converted into three-phase voltages;

In S5, motor control is performed, and the three-phase voltage output in step S4 is input to drive the permanent magnet synchronous motor.

Preferably, the preset anti-slip starting condition is that the following conditions are simultaneously satisfied:

The vehicle is in a driving gear, the vehicle speed is smaller than a certain value, the battery charging and discharging capability is normal without faults, the motor system is normal without over-temperature, the vehicle request torque is smaller than the motor actual torque, the road gradient is larger than a certain value, the vehicle creeping function is in a closed state, and the sensors related to the judging conditions are normal and the vehicle communication is normal.

According to a second aspect of the invention, a ramp auxiliary system based on motor control position loop control is provided, which comprises an anti-slip slope judging module, a position loop control module, a speed loop control module, a current loop control module and a motor control module;

The anti-slip judgment module is used for judging whether the vehicle meets the preset anti-slip starting condition or not, and enabling the vehicle to enter an anti-slip mode when the preset anti-slip starting condition is met;

the position ring control module is used for controlling a motor control position ring;

The speed loop control module is used for controlling the motor to control the speed loop;

The current loop control module is used for controlling the motor to control the current loop;

The motor module is used for driving the permanent magnet synchronous motor and obtaining the actual position, the actual speed and the three-phase current of the permanent magnet synchronous motor.

Preferably, the preset anti-slip starting condition is that the following conditions are simultaneously satisfied:

The vehicle is in a driving gear, the vehicle speed is smaller than a certain value, the battery charging and discharging capability is normal without faults, the motor system is normal without over-temperature, the vehicle request torque is smaller than the motor actual torque, the road gradient is larger than a certain value, the vehicle creeping function is in a closed state, and the sensors related to the judging conditions are normal and the vehicle communication is normal.

Compared with the prior art, the invention has the following beneficial effects:

The invention has the core that the position loop control in the motor control is introduced, the three-loop closed-loop control is realized in cooperation with the speed loop and the current loop control, the control precision of the motor can be greatly improved, the motor can be stopped at a designated position, the control precision of the motor can be improved, the hysteresis distance generated when the motor enters an anti-slip slope is reduced or even eliminated, and the anti-interference capability is strong.

Drawings

Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:

FIG. 1 is a schematic flow chart of the method described in example 1;

FIG. 2 is a schematic diagram of the method described in example 1;

fig. 3 is a schematic diagram of the system described in embodiment 2.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Further, all directional indications (such as up, down, left, right, front, rear, bottom.) in the present application are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indication is changed accordingly.

Example 1

The embodiment provides a ramp auxiliary method based on motor control position ring control, which can utilize a motor control position ring to input expected rotor position information, realize accurate control on a motor motion track, and the position ring is transmitted to a speed ring by receiving a control signal output by a controller, so that accurate control on the motor rotating speed and torque is realized, and finally, the motor can be ensured to accurately move to a designated position.

The motor control position loop can accurately track and dynamically adjust the rotor position, the method is characterized in that a working principle of the motor control position loop is briefly described, a target rotor position signal is generated according to the movement requirement of a vehicle, the actual position of the rotor is collected in real time through an encoder and calculated with a desired position to form a position error signal, the position error signal is processed by a position loop controller and then a rotating speed control command is output to a speed loop, the speed loop converts the rotating speed command into motor driving current to drive the motor to generate corresponding torque, meanwhile, the actual rotating speed is continuously monitored and compared with the target value, torque accurate output is achieved through current loop control, and finally the motor rotor is enabled to move strictly along the desired track through closed loop linkage, so that displacement deviation caused by sliding is eliminated.

In addition, describing the principle of PID control briefly, the control strategy widely used in process control is a control strategy for calculating the deviation between the actual output and the desired output of the system and adjusting the control amount according to the ratio, integral and Derivative of the deviation, so as to achieve the rapid, accurate and stable output of the system.

Specifically, as shown in fig. 1 and 2, the ramp assisting method based on motor control position loop control provided in this embodiment includes the following steps.

In step S1, when a preset anti-slip start condition is satisfied, the vehicle enters an anti-slip mode. Further, the preset anti-slip starting condition can be that the vehicle is in a driving gear, the vehicle speed is smaller than a certain value, the battery charging and discharging capability is normal without faults, the motor system is normal without over-temperature, the vehicle request torque is smaller than the motor actual torque, the road gradient is larger than a certain value, the vehicle creeping function is in a closed state, and the sensors related to the judging condition are normal and the vehicle communication is normal. When the preset anti-slip starting condition is met, the anti-slip mode is entered, the driving motor enters a zero-rotation speed mode from a torque control mode, and when the preset anti-slip starting condition is not met, the anti-slip mode is exited, and the motor returns to the torque control mode normally.

Further, the preset anti-slip starting condition further comprises the fact that the actual motor rotating speed is opposite to the current gear, for example, the vehicle is in D gear but the motor rotating speed is negative, the backward slip distance of the vehicle is estimated through integrating the negative change quantity of the motor rotating speed, and the backward slip distance of the vehicle exceeds a threshold value, for example, is larger than or equal to 5cm, and then the anti-slip function is achieved. Compared with the conventional anti-slip slope judgment dependent sensor, the judgment condition does not need an additional sensor, the cost of the whole vehicle is reduced, and meanwhile, the algorithm directly utilizes a motor signal, so that misjudgment caused by sensor faults is avoided.

In step S2, motor control position loop control is performed. If no position ring control is introduced, when the vehicle enters an anti-slip mode by means of rotating speed ring and current ring control, a 0 rotating speed request is input, and after the rotating speed ring and current ring control, the motor outputs a force opposite to a backward hysteresis acting force, so that the vehicle achieves a hill-holding effect, but the 0 rotating speed control mode usually introduces overshoot and oscillation of the rotating speed of the motor, and backward hysteresis and shaking (similar to spring contraction) of the vehicle can occur for the whole vehicle phenomenon. In contrast, when the position ring control is introduced, when the vehicle enters the anti-slip mode, a specific position requiring the rotation of the rotor is input, the motor can rotate to the requested position, the position is accurate, the anti-interference capability is strong, namely, after reaching an angle, the motor is difficult to rotate by external force, and thus the effect of parking is achieved.

Specifically, the Position loop control adopts proportional control (P), as shown in fig. 2, a target position_ref and an actual Position (θ) are input, and by the Position loop proportional control, a target Speed speed_ref is output, where the target position_ref is a desired motor rotor Position (may be obtained and preset according to a vehicle motion requirement), and the actual Position (θ) is an actual rotor Position of the permanent magnet synchronous motor read by the encoder. The position loop control adopts proportional control (P) to ensure that the position loop control does not generate overshoot, and the effect of quick response and no overshoot can be achieved. In other embodiments, the position loop control can also take the form of proportional-derivative control (PD) or proportional-integral control (PI).

In step S3, motor control speed loop control is performed. As shown in fig. 2, the target Speed speed_ref and the actual Speed ω are input, and the q-axis target current iq_ref and the d-axis target current id_ref are output by proportional-differential control, and the d-axis target current id_ref is set to 0. Wherein the actual speed ω is the actual rotational speed of the permanent magnet synchronous motor.

Further, in order to overcome the disturbance factors in the anti-slip speed loop control, such as the rotation speed stability problem caused by load addition, load subtraction and ramp resistance change, the motor control speed loop control preferably adopts Active Disturbance Rejection (ADRC) control, estimates the disturbance situation in real time through an extended state observer, calculates the compensation control quantity by combining with a preset compensation control strategy, and performs disturbance compensation. Accurate tracking of the rotating speed is realized.

In step S4, motor control current loop control is performed. As shown in fig. 2, the q-axis target current iq_ref and the d-axis target current id_ref, the q-axis actual current Iq, and the d-axis actual current Id are input, and the q-axis voltage Vq and the d-axis voltage Vd are output by proportional-differential control.

Furthermore, the current loop adopts complex vector PI control, dynamic decoupling is realized through pole-zero cancellation, compared with a conventional PI controller, the dynamic response is better, the complex vector PI can still keep independent control of d-q axis current under a high-speed working condition, current fluctuation is reduced, parameter self-tuning is realized, the sensitivity to motor parameters is reduced through frequency domain characteristic optimization parameters, and system adaptability is improved.

The q-axis actual current Iq and the d-axis actual current Id are obtained according to the three-phase current of the permanent magnet synchronous motor, wherein the obtaining mode is that the three-phase current Ia, ib and Ic of the permanent magnet synchronous motor are obtained, the alpha-axis current Ialpha and the beta-axis current Ibeta are generated through Clark conversion, and then the q-axis actual current Iq and the d-axis actual current Id are generated through Park conversion.

Then, the reverse Park operation (RevPark conversion) is performed, and the α -axis voltage vα and the β -axis voltage vβ in the two-phase stationary coordinate system (α - β coordinate system) are output according to the q-axis voltage Vq and the d-axis voltage Vd, and then, the voltage signal is converted into three-phase voltages Va, vb, and Vc by SVPMW (space vector pulse width modulation).

In S5, motor control is performed. As shown in fig. 2, three-phase voltages Va, vb, vc output in step S4 are input to drive a Permanent Magnet Synchronous Motor (PMSM). Meanwhile, position and Speed information (Speed & Position, including actual Position theta and actual Speed omega) of the permanent magnet synchronous motor and three-phase currents Ia, ib and Ic are obtained to realize three-loop closed-loop control of a Position loop, a Speed loop and a current loop.

Compared with the traditional anti-slip mode motor control mode, the method provided by the embodiment has the advantages that the position loop control is introduced to realize three-loop closed-loop control in cooperation with the speed loop and the current loop control, so that the control precision of the motor can be greatly improved, and the hysteresis distance generated when the motor enters an anti-slip mode is reduced or even eliminated.

Example 2

The present embodiment provides a ramp assist system based on motor control position loop control, and the method described in embodiment 1 can be implemented by cooperation between the modules. As shown in FIG. 3, the ramp auxiliary system based on motor control position loop control provided by the embodiment comprises an anti-slip slope judging module, a position loop control module, a speed loop control module, a current loop control module and a motor control module.

The anti-slip judgment module is used for judging whether the vehicle meets the preset anti-slip starting condition or not, and enabling the vehicle to enter an anti-slip mode when the preset anti-slip starting condition is met. The preset anti-slip starting condition can be that the vehicle is in a driving gear, the vehicle speed is smaller than a certain value, the battery charging and discharging capability is normal without faults, the motor system is normal without over-temperature, the vehicle request torque is smaller than the motor actual torque, the road gradient is larger than a certain value, the vehicle creeping function is in a closed state, and the sensors related to the judging conditions are normal and the vehicle communication is normal.

The motor module is used for driving the permanent magnet synchronous motor and acquiring Position and Speed information (Speed & Position, including actual Position theta and actual Speed omega) of the permanent magnet synchronous motor, and three-phase currents Ia, ib and Ic so as to realize three-loop closed-loop control of the Position loop, the Speed loop and the current loop.

It should be noted that, in embodiment 1, the explanation of the implementation and the beneficial effects of the ramp auxiliary method based on the motor control position loop control is also applicable to the system provided in this embodiment, and will not be repeated here.

While the present invention has been described with reference to the above embodiments, it is apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit of the invention.

Claims (4)

1. The ramp auxiliary method based on motor control position ring control is characterized by comprising the following steps:

step S1, when a preset anti-slip starting condition is met, the vehicle enters an anti-slip mode;

Step S2, motor control position loop control is carried out, a target position and an actual position are input, and target speed is output through position loop proportional control, wherein the actual position is the actual rotor position of the permanent magnet synchronous motor read by an encoder;

Step S3, motor control speed loop control is carried out, target speed and actual speed are input, q-axis target current and d-axis target current are output through active disturbance rejection control, and the d-axis target current is set to be 0, wherein the actual speed is the actual rotating speed of the permanent magnet synchronous motor;

In step S4, motor control current loop control is carried out, q-axis actual current and d-axis actual current are obtained and input according to three-phase current of a permanent magnet synchronous motor, q-axis target current and d-axis target current are input, dynamic decoupling is realized through zero pole cancellation through complex vector PI control, q-axis voltage and d-axis voltage are output, alpha-axis voltage and beta-axis voltage in a two-phase static coordinate system are output through inverse Park operation, and voltage signals are converted into three-phase voltages;

In S5, motor control is performed, and the three-phase voltage output in step S4 is input to drive the permanent magnet synchronous motor.

2. A ramp assist method based on motor control position loop control as claimed in claim 1, wherein the preset anti-slip start condition is that the following conditions are simultaneously satisfied:

The vehicle is in a driving gear, the vehicle speed is smaller than a certain value, the battery charging and discharging capability is normal without faults, the motor system is normal without over-temperature, the vehicle request torque is smaller than the motor actual torque, the road gradient is larger than a certain value, the vehicle creeping function is in a closed state, and the sensors related to the judging conditions are normal and the vehicle communication is normal.

3. The ramp auxiliary system based on motor control position loop control is characterized by comprising an anti-slip slope judging module, a position loop control module, a speed loop control module, a current loop control module and a motor control module;

The anti-slip judgment module is used for judging whether the vehicle meets the preset anti-slip starting condition or not, and enabling the vehicle to enter an anti-slip mode when the preset anti-slip starting condition is met;

the position ring control module is used for controlling a motor control position ring;

The speed loop control module is used for controlling the motor to control the speed loop;

The current loop control module is used for controlling the motor to control the current loop;

the motor control module is used for driving the permanent magnet synchronous motor and obtaining the actual position, the actual speed and the three-phase current of the permanent magnet synchronous motor.

4. A motor control position loop control based ramp assist system as in claim 3 wherein the preset anti-slip start condition is the simultaneous satisfaction of:

The vehicle is in a driving gear, the vehicle speed is smaller than a certain value, the battery charging and discharging capability is normal without faults, the motor system is normal without over-temperature, the vehicle request torque is smaller than the motor actual torque, the road gradient is larger than a certain value, the vehicle creeping function is in a closed state, and the sensors related to the judging conditions are normal and the vehicle communication is normal.