CN115913012A - Function type hybrid control method for driving motor of special electric vehicle - Google Patents

Abstract

The invention provides a functional hybrid control method for a driving motor of an electric special vehicle, which combines a fuzzy PID algorithm and a conventional PID control algorithm through a switching function to obtain the comprehensive advantages of the two control algorithms. Meanwhile, in order to reduce the calculation burden and the execution time of the controller and facilitate the engineering realization, a fuzzy proportional algorithm with the transient performance of a fuzzy PID algorithm is adopted for replacing. The operation state of the motor is studied in sections according to the operation condition of the special vehicle, and the weights of the outputs of the two control algorithms are determined by using a group of rules or an independent fuzzy algorithm, so that an additional fuzzy calculation is needed, the increased calculation time and gain constant adjustment can reduce the switching frequency of a control system, and the higher torque fluctuation condition is caused.

Description

A functional hybrid control method for driving motors of electric special vehicles

Technical Field

The present invention relates to the technical field of motor control, and in particular to a functional hybrid control method for a driving motor of an electric special vehicle.

Background Art

Permanent magnet synchronous motors and their control systems are widely used in the field of electric vehicles due to their high efficiency, high control accuracy, high torque density, good torque stability, and low vibration and noise. Electric vehicles equipped with permanent magnet synchronous motors have a complex working environment and require frequent starting, large acceleration and deceleration, and considering the mileage factor. This requires their control systems to have the characteristics of high system efficiency and strong adaptability. High-performance control strategies are applied to motor control systems to fully utilize the various potential capabilities of the motor and make the motor's working performance more in line with the requirements of use. As a special type of electric vehicle, electric special vehicles have new requirements for the stability, efficiency, and endurance of their working process due to the particularity of their operation and operation.

Traditional motor control technology has great drawbacks in terms of energy consumption, performance, and controllability, which is not conducive to improving the endurance, driving safety, operating safety, and comfort capabilities of electric special vehicles. Optimizing motors and their control technology is also the key to improving the operating performance of electric vehicles and promoting the development of the electric vehicle industry.

Summary of the invention

In view of the shortcomings of the prior art, it is considered that the intelligent algorithm has superior performance under transient conditions, while the PID controller has superior performance under steady-state conditions. The fuzzy PID algorithm and the conventional PID control algorithm are combined through a switching function to obtain the comprehensive advantages of the two control algorithms. In order to reduce the computational burden and execution time of the controller and facilitate engineering implementation, this patent proposes to use a fuzzy proportional algorithm with the transient performance of the fuzzy PID algorithm instead of the fuzzy method. At the same time, considering the use of a set of rules or a separate fuzzy algorithm to determine the weights of the outputs of the two control algorithms, an additional fuzzy calculation, more calculation time, and more gain constant adjustments are required. The increased amount of calculation will reduce the switching frequency of the control system, resulting in higher torque fluctuations. This patent further proposes a switching function hybrid control strategy, and designs a switching function to calculate the output weight to control the output ratio of the two.

The present invention provides a functional hybrid control method for a driving motor of an electric special vehicle, comprising the following steps:

Step 1: The vehicle starts, the motor controller is powered on, and the motor controller reads the throttle signal through the capture unit and converts it into a given speed n ^* (k) through calculation; at the same time, the motor controller collects the motor speed n(k) transmitted back through the rotary transformer;

Step 2: Calculate the speed deviation _en (k)=n ^* (k)-n(k) and the speed deviation change _ecn (k)= _en (k) _-en (k-1) by using the fuzzy proportional controller; where n ^* (k) represents the given speed at time k, _en (k) represents the speed difference at time k, and _en (k-1) represents the speed difference at time (k-1);

The current regulation output at time k is calculated by formula (1):

Among them, _Ke is the quantization factor of the fuzzy proportional controller;

Step 3: The PID controller calculates the current regulation output according to the speed deviation e _n (k) and the speed deviation change ec _n (k) in step 2 through formula (2):

为PID控制器(k-1)时刻输出的电流值；e_n(k)、2e_n(k-1)、e_n(k-2)分别为k、(k-1)、(k-2)时刻输出的速度偏差；Among them, k _p , k _i , k _d are the control parameters of the PID controller;

is the current value output by the PID controller at time (k-1); _en (k), _2en (k-1), and _en (k-2) are the speed deviations output at time k, (k-1), and (k-2) respectively;

和

的输出权重，根据公式(5)计算出最终的电流调节输出量iq^*(k)；Step 4: Calculate the current regulation output according to e _n (k) in step 2 through the switching function of formula (3) and formula (4)

and

The output weight of is calculated according to formula (5) to obtain the final current regulation output iq ^* (k);

f ₂ (x) = 1 - f ₁ (x) (4)

的权重，f₂(x)为

的权重；a、b为常数，根据实际操作经验选取。The value of x is the speed deviation _en (k), and f ₁ (x) is

The weight of f ₂ (x) is

The weight of; a, b are constants, selected according to actual operation experience.

Step 5: The three-phase currents ia, ib, and ic of the motor fed back by the current Hall sensor are collected through current analog-to-digital (A/D) interruption. After digital filtering, the vector static coordinate currents i _α and i _β are first obtained through Park transformation, and then the quadrature axis current iq and the direct axis current id are obtained through Clarke transformation.

Step 6: Compare the quadrature-axis given current iq ^* with the feedback quadrature-axis current iq to obtain the quadrature-axis current deviation e _iq (k) = iq ^* (k) - iq (k) and the quadrature-axis current deviation change ec _iq (k) = e _iq (k) - e _iq (k-1), where e _iq (k-1) is the quadrature-axis current deviation at time k-1; calculate the quadrature-axis voltage regulation output u _q (k) at time k through formula (6);

Wherein, _uq (k) represents the quadrature-axis voltage output at time k, _uq (k-1) represents the quadrature-axis voltage output at time k-1, _eiq (k), _eiq (k-1), _eiq (k-2) are the speed deviations output at time k, (k-1), (k-2) respectively;

Control the direct axis given current id ^* = 0; compare the direct axis given current id ^* with the feedback direct axis current id to obtain the direct axis current deviation e _id (k) = id ^* (k) - id (k) and the direct axis current deviation change ec _id (k) = e _id (k) - e _id (k-1); calculate the direct axis voltage regulation output _ud (k) at time k through formula (7);

u _d (k)＝u _d (k-1)+k _p ec _id (k)+k _i e _id (k)+k _d [e _id (k)-2e _id (k-1)+e _id ( k-2)] (7)

Wherein, _ud (k) represents the direct-axis voltage at time k, _ud (k-1) represents the direct-axis voltage at time k-1, _eid (k), _eid (k-1), and _eid (k-2) are the current deviations output at time k, (k-1), and (k-2), respectively;

Step 7: Perform Clarke inverse transformation on u _q (k) and _ud (k) to obtain αβ axis voltages u _α and u _β , and then calculate u _a , u _b , and u _c through Park inverse transformation; finally, the controller adjusts the values of TIM1 registers CCR1, CCR2, and CCR3 according to the three-phase voltages u _a , u _b , and u _c to control the SVPWM module to output six-channel PWM wave control signals, drive the inverter to work, and output variable amplitude and frequency to the three-phase winding of the motor stator to achieve speed control.

The beneficial effects of the present invention are:

1) High-performance control strategies are applied to motor control systems, which can fully utilize the various potential capabilities of the motor and make the motor's working performance more in line with the use requirements. In view of users' more high-performance requirements for special vehicles and the complex operating conditions of special vehicle drive motors, the motor control system cannot meet the effective control of the drive motor using a single control strategy. The present invention proposes an improved functional hybrid control method. According to the operating conditions of special vehicles, the operating state of the motor is studied in sections, and the two control algorithms suitable for each stage are integrated through switching functions to exert the high-performance output of the motor;

2) The key to the functional hybrid control method lies in the establishment of the switching function. The switching function needs to allocate the output timing or weight of each control algorithm, so the accuracy of the switching function determines the control performance of the control system. The present invention establishes a switching function by calculating and analyzing each control algorithm. It not only reduces the torque fluctuation caused by redundant calculation, but also accurately determines the output proportion of each algorithm controller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram of a functional hybrid controller for a driving motor of an electric special vehicle in the present invention;

FIG2 is a functional block diagram of a speed control system for a vector controlled electric vehicle drive motor according to the present invention;

FIG3 is a graph showing the relationship between output weight and speed deviation in the present invention;

FIG. 4 is a flowchart of the functional hybrid control method of the electric special vehicle drive motor in the present invention, which is based on the controller software with DSP as the core.

DETAILED DESCRIPTION

The invention will be further described below with reference to the accompanying drawings and specific implementation examples.

When electric special vehicles are running, their drive motors are often in various working states such as starting, acceleration, steady speed, deceleration, etc., accompanied by various interferences. It is difficult for a single control algorithm to meet the optimal control requirements of each working state. In order to ensure that electric special vehicles run smoothly in various working states such as starting, lifting and transporting, lifting operation, and no-load operation, avoid jitter, and enhance work efficiency, it is necessary to consider the output characteristics of the motor in each working state, and design a speed control algorithm that meets each stage to give full play to the optimal output performance of the motor. Considering that the intelligent algorithm has superior performance under transient conditions, while the PID controller has superior performance under steady-state conditions. Combining the fuzzy PID algorithm and the conventional PID control algorithm through a switching function can obtain the comprehensive advantages of the two control algorithms. At the same time, in order to reduce the calculation burden and execution time of the controller, it is easy to implement engineering, and according to the output of the fuzzy speed controller, at the beginning of the transient, its value is close to the maximum allowable output value, and it decreases as the speed error decreases. In order to further reduce the calculation amount of the fuzzy algorithm, a fuzzy proportional controller is designed to replace the fuzzy PID controller. The fuzzy proportional controller is a proportional adjustment controller whose gain adjustment is realized under the constraint of the limiter. The output of the fuzzy proportional controller is equivalent to the output of the fuzzy controller at the beginning of the transient.

Considering using a set of rules or a separate fuzzy algorithm to determine the weight of the output of the two control algorithms, an additional fuzzy calculation, more calculation time, and more gain constant adjustments are required. The increased amount of calculation will reduce the switching frequency of the control system, resulting in higher torque fluctuations. The switching function is designed to calculate the output weight to control the output ratio of the two. The control principle block diagram is shown in Figure 1.

The permanent magnet synchronous motor control of electric special vehicles adopts space vector control. The principle of its speed control system is shown in Figure 2. The speed control system consists of the following five parts: speed loop (functional hybrid controller), two current loop controllers (current PID controller); coordinate conversion module; space vector pulse width modulation module; inverter module; position and speed detection module.

Control process: Given a speed signal, calculate the difference with the detected speed, and output it after adjustment by fuzzy proportional controller and conventional PID control. At the same time, the switching function determines the output weights of the two controllers according to the slip, and calculates and outputs the quadrature axis current component as the given signal i _qref of the q-axis current PID regulator; at the same time, after coordinate transformation, the stator feedback current changes from i _abc to i _d , i _q ; the given quadrature axis current i _qref is calculated to be different from the transformed quadrature axis current i _q , and the quadrature axis reference voltage u _qref is output after the current PID adjustment machine; the direct axis given current i _dref = 0 is controlled, and the difference is calculated with the transformed i _d , and the direct axis reference voltage u _dref is output after the current PID adjustment; u _dref , u _qref are transformed by 2r/s to obtain the αβ axis voltage, and then u _a , u _b , u _c are calculated by Park inverse transformation. Finally, the six-way PWM wave control signal is output through the SVPWM module to drive the inverter to work and output variable amplitude and frequency to the three-phase winding of the motor stator.

The design idea of the present invention is: when the electric special vehicle is running, in order to ensure the stability of its operation and the optimal output performance of each stage, a control algorithm that meets each stage needs to be designed. When the drive motor is running at a steady speed, the conventional PID control has excellent control performance due to its small amount of calculation and simple control structure. When the drive motor is running at a large speed change or there is interference, the fuzzy proportional control algorithm can adjust the control parameters according to the changing environment, and the control performance is excellent. Combining the fuzzy proportional control algorithm with the conventional PID control algorithm can obtain the comprehensive advantages of the two control algorithms. Using a set of rules or a separate fuzzy algorithm to determine the weight of the output of the two control algorithms requires an additional fuzzy calculation, more calculation time, and more gain constant adjustment. The increased amount of calculation will reduce the switching frequency of the control system, resulting in higher torque fluctuations and reducing the stability of the vehicle operation. In order to solve this problem, a switching function is designed to calculate the output weight to control the output ratio of the two algorithm controllers. Finally, the optimal control output performance of the drive motor in each state is achieved to ensure the output performance of the electric vehicle such as acceleration performance, stability performance, and work efficiency.

As shown in FIG4 , a functional hybrid control method for a driving motor of an electric special vehicle includes the following steps:

Step 1: The vehicle starts, the motor controller is powered on, and the motor controller reads the throttle signal through the capture unit and converts it into a given speed n ^* (k) through calculation; at the same time, the motor controller collects the motor speed n(k) transmitted back through the rotary transformer;

Step 2: Calculate the speed deviation _en (k)=n ^* (k)-n(k) and the speed deviation change _ecn (k)= _en (k) _-en (k-1) by using the fuzzy proportional controller; where n ^* (k) represents the given speed at time k, _en (k) represents the speed difference at time k, and _en (k-1) represents the speed difference at time (k-1);

The current regulation output at time k is calculated by formula (1):

Among them, _Ke is the quantization factor of the fuzzy proportional controller;

Step 3: The PID controller calculates the current regulation output according to the speed deviation e _n (k) and the speed deviation change ec _n (k) in step 2 through formula (2):

为PID控制器(k-1)时刻输出的电流值；e_n(k)、2e_n(k-1)、e_n(k-2)分别为k、(k-1)、(k-2)时刻输出的速度偏差；Among them, k _p , k _i , k _d are the control parameters of the PID controller;

is the current value output by the PID controller at time (k-1); _en (k), _2en (k-1), and _en (k-2) are the speed deviations output at time k, (k-1), and (k-2) respectively;

和

的输出权重，输出权重与速度偏差关系曲线图的如图3所示，根据公式(5)计算出最终的电流调节输出量iq^*(k)；Step 4: Calculate the current regulation output according to e _n (k) in step 2 through the switching function of formula (3) and formula (4)

and

The output weight and the relationship curve between the output weight and the speed deviation are shown in FIG3 . The final current regulation output iq ^* (k) is calculated according to formula (5);

f ₂ (x) = 1 - f ₁ (x) (4)

的权重，f₂(x)为

的权重；a、b为常数，根据实际操作经验选取。The value of x is the speed deviation e _n (k), and f ₁ (x) is

The weight of f ₂ (x) is

The weight of; a, b are constants, selected according to actual operation experience.

Step 5: The three-phase currents ia, ib, and ic of the motor fed back by the current Hall sensor are collected through current analog-to-digital (A/D) interruption. After digital filtering, the vector static coordinate currents i _α and i _β are first obtained through Park transformation, and then the quadrature axis current iq and the direct axis current id are obtained through Clarke transformation.

Step 6: Compare the quadrature-axis given current iq ^* with the feedback quadrature-axis current iq to obtain the quadrature-axis current deviation e _iq (k) = iq ^* (k) - iq (k) and the quadrature-axis current deviation change ec _iq (k) = e _iq (k) - e _iq (k-1), where e _iq (k-1) is the quadrature-axis current deviation at time k-1; calculate the quadrature-axis voltage regulation output u _q (k) at time k through formula (6);

Wherein, _uq (k) represents the quadrature-axis voltage output at time k, _uq (k-1) represents the quadrature-axis voltage output at time k-1, _eiq (k), _eiq (k-1), _eiq (k-2) are the speed deviations output at time k, (k-1), (k-2) respectively;

Control the direct axis given current id ^* = 0; compare the direct axis given current id ^* with the feedback direct axis current id to obtain the direct axis current deviation e _id (k) = id ^* (k) - id (k) and the direct axis current deviation change ec _id (k) = e _id (k) - e _id (k-1); calculate the direct axis voltage regulation output _ud (k) at time k through formula (7);

u _d (k)＝u _d (k-1)+k _p ec _id (k)+k _i e _id (k)+k _d [e _id (k)-2e _id (k-1)+e _id ( k-2)] (7)

Wherein, _ud (k) represents the direct-axis voltage at time k, _ud (k-1) represents the direct-axis voltage at time k-1, _eid (k), _eid (k-1), and _eid (k-2) are the current deviations output at time k, (k-1), and (k-2), respectively;

Step 7: Perform Clarke inverse transformation on u _q (k) and _ud (k) to obtain αβ axis voltages u _α and u _β , and then calculate u _a , u _b , and u _c through Park inverse transformation; finally, the controller adjusts the values of TIM1 registers CCR1, CCR2, and CCR3 according to the three-phase voltages u _a , u _b , and u _c to control the SVPWM module to output six-channel PWM wave control signals, drive the inverter to work, and output variable amplitude and frequency to the three-phase winding of the motor stator to achieve speed control.

Claims (3)

1. A functional hybrid control method for a driving motor of an electric special vehicle, characterized by comprising: Step 1: The vehicle starts, the motor controller is powered on, and the motor controller reads the throttle signal through the capture unit and converts it into a given speed n ^* (k) through calculation; at the same time, the motor controller collects the motor speed n(k) transmitted back through the rotary transformer; Step 2: Calculate the speed deviation _en (k)=n ^* (k)-n(k) and the speed deviation change _ecn (k)= _en (k) _-en (k-1) by using the fuzzy proportional controller; where n ^* (k) represents the given speed at time k, _en (k) represents the speed difference at time k, and _en (k-1) represents the speed difference at time (k-1); The current regulation output at time k is calculated by formula (1):

Among them, _Ke is the quantization factor of the fuzzy proportional controller; Step 3: The PID controller calculates the current regulation output according to the speed deviation e _n (k) and the speed deviation change ec _n (k) in step 2 through equation (2):

Among them, k _p , k _i , k _d are the control parameters of the PID controller;

is the current value output by the PID controller at time (k-1); _en (k), _2en (k-1), and _en (k-2) are the speed deviations output at time k, (k-1), and (k-2) respectively; Step 4: Determine the Current Regulated Output

and

The output weight of is used to calculate the final current regulation output iq ^* (k); Step 5: The three-phase currents ia, ib, and ic of the motor fed back by the current Hall sensor are collected through current analog interruption. After digital filtering, the vector static coordinate currents i _α and i _β are first obtained through Park transformation, and then the quadrature axis current iq and the direct axis current id are obtained through Clarke transformation. Step 6: Compare the quadrature-axis given current iq ^* with the feedback quadrature-axis current iq to obtain the quadrature-axis current deviation e _iq (k) = iq ^* (k) - iq (k) and the quadrature-axis current deviation change ec _iq (k) = e _iq (k) - e _iq (k-1), where e _iq (k-1) is the quadrature-axis current deviation at time k-1; calculate the quadrature-axis voltage regulation output u _q (k) at time k; Control the direct-axis given current id ^* = 0; compare the direct-axis given current id ^* with the feedback direct-axis current id to obtain the direct-axis current deviation e _id (k) = id ^* (k) - id (k) and the direct-axis current deviation change ec _id (k) = e _id (k) - e _id (k-1); calculate the direct-axis voltage regulation output _ud (k) at time k; Step 7: Perform Clarke inverse transformation on u _q (k) and _ud (k) to obtain αβ axis voltages u _α and u _β , and then calculate u _a , u _b , and u _c through Park inverse transformation; finally, the controller adjusts the values of TIM1 registers CCR1, CCR2, and CCR3 according to the three-phase voltages u _a , u _b , and u _c to control the SVPWM module to output six-channel PWM wave control signals, drive the inverter to work, and output variable amplitude and frequency to the three-phase winding of the motor stator to achieve speed control. 2. The functional hybrid control method for a driving motor of an electric special vehicle according to claim 1, characterized in that in step 4

The weight f ₁ (x),

The weight f ₂ (x) is calculated as follows:

f ₂ (x) = 1 - f ₁ (x) (4) The final current regulation output iq ^* (k) is expressed as:

The value of x is the speed deviation _en (k), and f ₁ (x) is

The weight of f ₂ (x) is

The weight of ; a and b are constants. 3. The functional hybrid control method for a driving motor of an electric special vehicle according to claim 1, characterized in that the quadrature-axis voltage regulation output u _q (k) in step 5 is expressed as:

Wherein, _uq (k) represents the quadrature-axis voltage output at time k, _uq (k-1) represents the quadrature-axis voltage output at time k-1, _eiq (k), _eiq (k-1), _eiq (k-2) are the speed deviations output at time k, (k-1), (k-2) respectively; The direct-axis voltage regulation output _ud (k) is expressed as: u _d (k)＝u _d (k-1)+k _p ec _id (k)+k _i e _id (k)+k _d [e _id (k)-2e _id (k-1)+e _id ( k-2)] (7) In the formula, _ud (k) represents the direct-axis voltage at time k, _ud (k-1) represents the direct-axis voltage at time k-1, _eid (k), _eid (k-1), and _eid (k-2) are the current deviations output at times k, (k-1), and (k-2), respectively.

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