CN111327235A - Commutation control device and method for permanent magnet DC motor based on sliding mode observer - Google Patents

Abstract

The invention discloses a commutation control device and method for a permanent magnet DC motor based on a sliding mode observer. The device includes a processor module, a voltage sampling module, a current sampling module, an optoelectronic isolation module, and the like; wherein, the processor module The input end is connected with a voltage sampling module and a current sampling module, and the output end is connected with a photoelectric isolation module, and the data obtained by the voltage sampling module and the current sampling module is used to construct a sliding mode observer to realize motor commutation and closed-loop control; the voltage sampling module A permanent magnet DC motor is connected to the input end of the current sampling module, and the output end is connected to a processor module input; the input end of the optoelectronic isolation module is connected to the processor module input, and the output end is connected to a drive circuit module; the drive circuit module input The photoelectric isolation module is connected to the end, and the permanent magnet DC motor is connected to the output end. The present invention is applied to a position sensorless control system of a permanent magnet direct current motor, calculates the back electromotive force in real time, and realizes the control of commutation.

Description

Commutation control device and method for permanent magnet DC motor based on sliding mode observer

technical field

The invention relates to a position sensorless commutation control device for a permanent magnet direct current motor, in particular to a permanent magnet direct current motor commutation control device and method based on a sliding mode observer.

Background technique

The permanent magnet DC motor body has the advantages of simple physical structure, rapid speed adjustment response, strong load capacity and high power factor. Therefore, this type of motor has important application value in production activities in various fields of human beings.

In order to detect continuous permanent magnet DC motor rotor position information and realize the commutation control of the motor, permanent magnet DC motors generally use electromagnetic induction, Hall magnetic sensitive or photoelectric sensors for rotor position detection. However, the above-mentioned position sensor not only increases the size and cost of the motor, and is difficult to maintain, and because the external connection circuit of the sensor is complicated, it is easy to be polluted by harmonics, which not only increases the difficulty in the production method, but also greatly limits the permanent magnet DC. Motors are used in applications where some system requirements (such as satellite instruments) are high. Therefore, the research on the position sensorless control system has become a hot spot in the field of motor control recently.

Although the position detection device is no longer installed on the rotor, during the operation of the motor, in order to control the motor commutation caused by the turn-off and turn-on of the inverter power device, it is still necessary to obtain the rotor position information. The most widely used method is: back EMF zero-crossing detection method. However, the back electromotive force cannot be directly detected by the detection device, which requires establishing a mathematical model by measuring the electrical signals such as current and voltage that can be measured by the permanent magnet DC motor body, and indirectly obtaining the zero-crossing point of the back electromotive force by calculating its variation in real time. , and then realize the commutation control.

By constructing an observer with known state quantities, the observed value of the back electromotive force is obtained, and the commutation control of the motor is realized. It has the characteristics of simple principle and good stability. However, when there is a sudden load change and system parameter transformation, the control system cannot guarantee the rotor. Accurate position detection and stable commutation.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a commutation control device and method for a permanent magnet DC motor based on a sliding mode observer, which can be applied to a position sensorless control system of a permanent magnet DC motor, calculate the back electromotive force in real time, and realize the commutation phase control. The commutation control device uses a sliding mode observer, which can run stably in the case of sudden load changes and system parameter transformations.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions to realize:

A permanent magnet DC motor commutation control device based on a sliding mode observer includes a processor module, a voltage acquisition module, a current acquisition module, an optoelectronic isolation module and a drive circuit module; wherein,

The input end of the processor module is connected with a voltage sampling module and a current sampling module, and the output end is connected with an optoelectronic isolation module, and the data obtained by the voltage sampling module and the current sampling module is used to construct a sliding mode observer to realize motor commutation and closed-loop control; The input end of the voltage sampling module and the current sampling module is connected with a permanent magnet DC motor, and the output end is connected with the processor module input; the input end of the optoelectronic isolation module is connected with the processor module input, and the output end is connected with the drive circuit module; The input end of the drive circuit module is connected with a photoelectric isolation module, and the output end is connected with a permanent magnet DC motor.

A further improvement of the present invention lies in that the processor module adopts STC15W404 single-chip microcomputer, which is used to analyze and calculate the analog data collected by the voltage acquisition module and the current acquisition module to obtain the rotor position information, and output and control the permanent magnet DC motor commutation, Digital PWM signal for speed and torque calculation;

The voltage acquisition module is used to collect the three-phase voltage analog quantity of the permanent magnet DC motor and transmit the data to the processor module;

The current acquisition module adopts the LM358 operational amplifier, which is used to collect the three-phase current analog quantity of the permanent magnet DC motor and transmit the data to the processor module;

The photoelectric isolation module adopts P521-4 photoelectric isolation chip, which is used to realize photoelectric conversion, isolate the STC15W404 single-chip microcomputer and the motor drive circuit, avoid mutual interference of signals, and avoid damage to the single-chip microcomputer due to excessive feedback current signal;

The driving circuit module adopts a field effect transistor with a model of IRF9540N, which is used to control the rotation angle and running speed of the motor and realize the control of the duty ratio.

The commutation control method of permanent magnet DC motor based on sliding mode observer includes: acquiring the current and voltage signals of the rotor detection circuit, and performing Clark transform on the current and voltage signals; constructing a sliding mode observer, and obtaining the back electromotive force through the sliding mode observer Observation value; calculate the rotor position of the motor through the back electromotive force observation value to obtain the motor speed; perform the rotation speed PI calculation and the torque PI calculation to realize the closed-loop control.

A further improvement of the present invention is that the current and voltage signals of the rotor detection circuit are obtained, and Clark transform is performed on the current and voltage signals, and the current calculation process is as follows:

同理可得克拉克变换后的电压u_α，u_β；

In the same way, the voltages u _α and u _β after the Clark transform can be obtained;

The mathematical model of the motor in the two-phase stationary coordinate system is:

in

In the formula: i _α and i _β are the stator currents in the two-phase static coordinate system; u _α and u _β are the stator voltages in the two-phase static coordinate system; e _α and e _β are the two-phase static coordinate systems. Back EMF; R, L are the winding phase resistance and equivalent inductance; ψ _f is the permanent magnet flux linkage; ω is the rotor angular velocity; θ is the rotor angle.

A further improvement of the present invention is that a sliding mode observer is constructed, and the back electromotive force observation value is obtained through the sliding mode observer; the calculation process of the sliding mode observer is as follows:

According to the mathematical model of permanent magnet DC motor, a sliding mode observer is constructed

In the formula: '^' is the observed value; k ₁ and k ₂ are the sliding mode gains; F( ) is the switching function, which adopts the sign function;

The sliding mode observer error equation can be expressed as

当系统进入滑模面后，

根据滑模观测器误差方程得到反电动势观测值为

其中：

The sliding die cut surface is defined as:

When the system enters the sliding surface,

According to the error equation of the sliding mode observer, the observed value of the back EMF is obtained as

in:

A further improvement of the present invention is that the rotor position of the motor is calculated through the back electromotive force observation value to obtain the motor speed, and the calculation process is as follows:

Motor rotor position:

Motor speed:

Compared with the prior art, the present invention at least has the following beneficial technical effects:

1. The present invention adopts a permanent magnet DC motor position sensorless control system, and does not require additional installation of a rotor detection module, further reducing the size and development cost of the permanent magnet DC motor;

2. The present invention adopts the sliding mode observer to calculate the back electromotive force, obtains the rotor position, and then realizes the commutation of the motor. The observer algorithm is relatively simple, and the rotor position obtained by the mathematical method is accurate;

3. The present invention adopts a double closed-loop control system of rotational speed and torque, and the whole system has good robust performance;

4. The optoelectronic isolation module of the present invention adopts the P521-4 optoelectronic isolation chip, which makes there no direct electrical signal connection between the input PWM signal of the processor and the drive bridge, and at the same time makes the circuit signal transmission free from external electromagnetic interference, which increases the resistance of the circuit. Interference ability.

Description of drawings

Fig. 1 is the hardware system block diagram of the present invention;

2 is a schematic diagram of a processor module of the present invention;

Fig. 3 is the principle diagram of the voltage sampling module of the present invention;

4 is a schematic diagram of a current sampling module of the present invention;

Fig. 5 is the principle diagram of the photoelectric isolation module of the present invention;

6 is a schematic diagram of a drive module of the present invention;

Fig. 7 is the software main program flow chart of the present invention;

FIG. 8 is a flowchart of a software interrupt program of the present invention.

Detailed ways

The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings.

As shown in FIG. 1 , the sliding mode observer-based permanent magnet DC motor commutation control device provided by the present invention includes: a processor module, a voltage sampling module, a current sampling module, an optoelectronic isolation module and a drive circuit module. The analog quantity acquisition channel of the processor module is connected to the voltage sampling module and the current adopting module, and the digital PWM output end of the processor module is connected to the photoelectric isolation module. The photoelectric isolation module is connected with the driving circuit module for driving the permanent magnet synchronous motor. The drive circuit module is connected to the three phases of the permanent magnet synchronous motor A, B, and C.

As shown in Figure 2, the processor module is composed of STC15W404 single-chip microcomputer. The power supply range of STC15W404 microcontroller is 2.6-5.5V, and the maximum normal operating current is 0.1uA. In addition, it also has 4KB Flash space, 512 bytes SRAM space, 9KB EEPROM, and built-in reset circuit with high reliability , clock circuit and 6 PWM output ports. Wherein, the processor module is used to analyze and calculate the analog data collected by the voltage collection module and the current collection module to obtain rotor position information, and output and control the commutation, rotational speed and torque of the permanent magnet DC motor. Calculated digital PWM signal to the opto-isolated module.

As shown in FIG. 3 , the voltage sampling module is composed of related resistors and capacitors. Mainly, the three-phase voltages of U, V, and W of the permanent magnet DC motor are bucked and low-pass filtered, and then the signals are sent to the processor module. Among them: R15 and R26 form a U-phase voltage drop circuit; R22 and R27 form a V-phase voltage drop circuit; R24 and R28 form a W-phase voltage drop circuit; Among them: R15 and C5 form a U-phase low-pass filter circuit; R22 and C6 form a V-phase voltage drop circuit Phase low-pass filter circuit; R24 and C4 constitute W-phase low-pass filter circuit. Among them: R16, R23, R25 play the role of current limiting.

As shown in Figure 4, the current sampling module is composed of an LM358 operational amplifier, related resistors and capacitors. Mainly, the U, V, W three-phase current signals of the permanent magnet DC motor are sent to the processor module.

As shown in Figure 5, the optoelectronic isolation module is composed of P521-4 optoelectronic isolation chips P1, P2 and related resistances. The four pins of the optoelectronic isolation chip P1 are connected to the (1) processor module, and the two pins of the optoelectronic isolation chip P2 are connected to the processor module. Its main functions are: 1. Realize photoelectric conversion; 2. Isolate the processor module (5) drive circuit module to avoid mutual interference of signals; 3. Avoid damage to the single-chip microcomputer due to excessive feedback current signal.

As shown in Figure 6, the drive circuit module is composed of field effect transistors VT1, VT2, VT3, VT4, VT5, and VT6 with model IRF9540N, related resistors, freewheeling diodes, drive output ports and power supply interfaces. The drive circuit module supplies power to the three-phase stator windings of the permanent magnet synchronous motor to drive the motor to run. The on-off control state of each transistor of the drive circuit module is shown in Table 1.

Table 1 On-off control state of transistors

As shown in Figure 7, the software main program flow chart includes: 1. System initialization is to configure the internal resources of the main processor module, mainly including: 1) Setting the external interrupt trigger mode, 2) PWM output port configuration, 3) System Clock resource configuration, 4) Control parameter configuration. 4) Configure the communication mode between the configuration and the processor module. 2. To complete the motor starting, the present invention adopts the "three-stage" starting method, which is divided into: 1) rotor pre-positioning, 2) external synchronous acceleration, and 3) self-synchronous switching.

As shown in FIG. 8 , the flowchart of the software interrupt program includes: 1) Obtaining the current and voltage signals of the rotor detection circuit, and performing Clark transform on the current and voltage signals. 2) A sliding mode observer is constructed, and the back EMF observation value is obtained through the sliding mode observer. 3) Calculate the rotor position of the motor through the observation value of the back electromotive force to obtain the motor speed. 4) Speed and torque closed-loop control.

1) Obtain the current and voltage signals of the rotor detection circuit, and perform Clark transform on the current and voltage signals. The current calculation process is as follows:

同理可得克拉克变换后的电压u_α，u_β。

In the same way, the voltages u _α and u _β after the Clark transform can be obtained.

The mathematical model of the motor in the two-phase stationary coordinate system is:

in

In the formula: i _α and i _β are the stator currents in the two-phase static coordinate system; u _α and u _β are the stator voltages in the two-phase static coordinate system; e _α and e _β are the two-phase static coordinate systems. Back EMF; R, L are the winding phase resistance and equivalent inductance; ψ _f is the permanent magnet flux linkage; ω is the rotor angular velocity; θ is the rotor angle.

2) Construct a sliding mode observer, and obtain the back EMF observation value through the sliding mode observer. The calculation process of the sliding mode observer is as follows:

According to the mathematical model of permanent magnet DC motor, a sliding mode observer is constructed

In the formula: '^' is the observed value; k ₁ and k ₂ are the sliding mode gains; F( ) is the switching function, which adopts the sign function.

The sliding mode observer error equation can be expressed as

当系统进入滑模面后，

根据滑模观测器误差方程可以得到反电动势观测值为

其中：

The sliding die cut surface is defined as:

When the system enters the sliding surface,

According to the error equation of the sliding mode observer, the observed value of the back EMF can be obtained as

in:

3) Calculate the rotor position of the motor through the back electromotive force observation value to obtain the motor speed, and the calculation process is as follows:

Motor rotor position:

Motor speed:

The 4) speed and torque closed-loop control is to perform the speed PI calculation and the torque PI calculation to realize the closed-loop control.

The above are only preferred embodiments of the present invention and do not limit the present invention. Any simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technology of the present invention. within the scope of the program.

Claims (6)

1. the permanent magnet DC motor commutation control device based on sliding mode observer, is characterized in that, comprises processor module, voltage acquisition module, current acquisition module, photoelectric isolation module and drive circuit module; Wherein, The input end of the processor module is connected with a voltage sampling module and a current sampling module, and the output end is connected with an optoelectronic isolation module, and the data obtained by the voltage sampling module and the current sampling module is used to construct a sliding mode observer to realize motor commutation and closed-loop control; The input end of the voltage sampling module and the current sampling module is connected with a permanent magnet DC motor, and the output end is connected with the processor module input; the input end of the optoelectronic isolation module is connected with the processor module input, and the output end is connected with the drive circuit module; The input end of the drive circuit module is connected with a photoelectric isolation module, and the output end is connected with a permanent magnet DC motor. 2. the permanent magnet direct current motor commutation control device based on sliding mode observer according to claim 1, is characterized in that, the adoption of STC15W404 single-chip microcomputer of processor module, is used for the simulation that voltage acquisition module and current acquisition module gather The rotor position information is obtained by analyzing and calculating the quantitative data, and the digital PWM signal for controlling the commutation, speed and torque calculation of the permanent magnet DC motor is output; The voltage acquisition module is used to collect the three-phase voltage analog quantity of the permanent magnet DC motor and transmit the data to the processor module; The current acquisition module adopts the LM358 operational amplifier, which is used to collect the three-phase current analog quantity of the permanent magnet DC motor and transmit the data to the processor module; The photoelectric isolation module adopts P521-4 photoelectric isolation chip, which is used to realize photoelectric conversion, isolate the STC15W404 single-chip microcomputer and the motor drive circuit, avoid mutual interference of signals, and avoid damage to the single-chip microcomputer due to excessive feedback current signal; The driving circuit module adopts a field effect transistor with a model of IRF9540N, which is used to control the rotation angle and running speed of the motor and realize the control of the duty ratio. 3. The permanent magnet DC motor commutation control method based on sliding mode observer is characterized in that, the method is based on the sliding mode observer-based permanent magnet DC motor commutation control device according to claim 1 or 2, comprising: obtaining The current and voltage signals of the rotor are detected, and Clark transform is performed on the current and voltage signals; a sliding mode observer is constructed, and the back EMF observation value is obtained through the sliding mode observer; the motor rotor position is calculated through the back EMF observation value to obtain the motor speed; Speed PI operation and torque PI operation realize closed-loop control. 4. The permanent magnet DC motor commutation control method based on sliding mode observer according to claim 3, is characterized in that, obtaining the current and voltage signals of the rotor detection circuit, carrying out Clark transform to the current and voltage signals, and the current calculation process as follows:

In the same way, the voltages u _α and u _β after the Clark transform can be obtained; The mathematical model of the motor in the two-phase stationary coordinate system is:

in

In the formula: i _α and i _β are the stator currents in the two-phase static coordinate system; u _α and u _β are the stator voltages in the two-phase static coordinate system; e _α and e _β are the two-phase static coordinate systems. Back EMF; R, L are the winding phase resistance and equivalent inductance; ψ _f is the permanent magnet flux linkage; ω is the rotor angular velocity; θ is the rotor angle. 5. The permanent magnet DC motor commutation control device based on the sliding mode observer according to claim 4, wherein the sliding mode observer is constructed, and the back EMF observation value is obtained by the sliding mode observer; the sliding mode observer calculates The process is as follows: According to the mathematical model of permanent magnet DC motor, a sliding mode observer is constructed

In the formula: '^' is the observed value; k ₁ and k ₂ are the sliding mode gains; F( ) is the switching function, which adopts the sign function; The sliding mode observer error equation can be expressed as

The sliding die cut surface is defined as:

When the system enters the sliding surface,

According to the error equation of the sliding mode observer, the observed value of the back EMF is obtained as

in:

6. the permanent magnet direct current motor commutation control device based on sliding mode observer according to claim 5, is characterized in that, calculates motor rotor position by back electromotive force observation value and then obtains motor rotational speed, and calculation process is as follows: Motor rotor position:

Motor speed:

Images