阅读说明：本技术 一种永磁同步电主轴的调速系统及其控制方法 (Speed regulating system of permanent magnet synchronous electric spindle and control method thereof ) 是由 单文桃 李坤 吴战 刘意 于 2019-07-18 设计创作，主要内容包括：本发明属于数控加工领域,为了解决永磁同步电机的快速响应能力差且受转矩脉动影响的问题,提供了一种永磁同步电主轴的调速系统及其控制方法,调速系统,包括：主电路和控制电路,主电路包括功率逆变电路和永磁同步电机,永磁同步电机的电主轴与功率逆变电路相连,控制电路包括：转速调节器、磁链发生器、转矩调节器、磁链调节器、两个电流滞环比较器、SVPWM、磁链观测器和电压矢量表,本发明采用基于混合驱动控制代替传统的矢量控制和直接转矩控制,使系统具有更好的快速响应能力,通过电压矢量开关表间接的控制转矩与磁链,有效抑制了直接转矩系统中产生的转矩脉动问题。(The invention belongs to the field of numerical control machining, and provides a speed regulating system of a permanent magnet synchronous electric spindle and a control method thereof in order to solve the problems that a permanent magnet synchronous motor is poor in quick response capability and is influenced by torque pulsation, wherein the speed regulating system comprises: main circuit and control circuit, main circuit include power inverter circuit and PMSM, and PMSM's electricity main shaft links to each other with power inverter circuit, and control circuit includes: the invention adopts hybrid drive control to replace the traditional vector control and direct torque control, so that the system has better quick response capability, and the torque and flux linkage are indirectly controlled through the voltage vector switch table, thereby effectively inhibiting the torque ripple problem generated in a direct torque system.)

1. A speed control system of a permanent magnet synchronous electric spindle is characterized by comprising:

the main circuit comprises a power inverter circuit and a permanent magnet synchronous motor, and an electric main shaft of the permanent magnet synchronous motor is connected with the power inverter circuit;

a control circuit, the control circuit comprising: the magnetic flux linkage control system comprises a rotating speed regulator, a magnetic flux linkage generator, a torque regulator, a magnetic flux linkage regulator, two current hysteresis comparators, a SVPWM (space vector pulse width modulation), a magnetic flux linkage observer and a voltage vector table, wherein the rotating speed regulator, the torque regulator and one of the current hysteresis comparators are connected with the voltage vector table in series, the magnetic flux linkage generator is connected on the rotating speed regulator in parallel, the magnetic flux linkage regulator is connected with the other current hysteresis comparator in series and then is arranged in parallel with the torque regulator, the magnetic flux linkage observer is connected between an electric main shaft and the voltage vector table and is connected with the two current hysteresis comparators and used for controlling the calculation of a stator magnetic flux linkage phase angle in current coordinate transformation and direct torque control, and the current hysteresis comparators are used for controlling the voltage vector switch table and further controlling torque and magnetic flux linkage.

2. The control method of the speed control system of the permanent magnet synchronous electric spindle according to claim 1, characterized in that: the method comprises the following steps:

s1, taking the difference between the actual rotating speed and the rated rotating speed of the permanent magnet synchronous electric spindle as the given value of the rotating speed governor;

s2, outputting rotor flux linkage according to flux linkage generating functionRespectively pass through a torque regulator and a flux linkage regulator to obtainAndcomparing the current deviation with an actual value to obtain a current deviation;

s3, generating a mark signal-1, 0 or 1 according to the current replacement comparator, and controlling the output of the voltage vector switch table according to the stator flux linkage phase angle;

and S4, determining the on-off of the power inverter circuit according to the voltage vector switch table, outputting a corresponding voltage vector, and realizing the hybrid drive control of the permanent magnet synchronous electric spindle.

3. The method as claimed in claim 2, wherein the hybrid drive control is combined with vector control and direct torque control, the d-axis and q-axis currents of the electric spindle are generated by vector control, the hysteresis control of the excitation current and the torque current and the voltage vector table are generated by the direct torque control system.

4. The control method of the governor system of a permanent magnet synchronous electric spindle according to claim 2, wherein the current coordinate system transformation and the stator flux phase angle of the hybrid drive control are obtained according to a flux linkage observer in combination with a vector control and direct torque control flux linkage observer.

5. The control method of the speed control system of the permanent magnet synchronous electric spindle according to claim 2, wherein the stator current is obtained by a vector control method.

6. The method of claim 2, wherein the control vector of the voltage vector switch controls the stator current and thus the torque and flux linkage.

Technical Field

The invention belongs to the field of numerical control machining, and particularly relates to a speed regulating system of a permanent magnet synchronous electric spindle and a control method thereof.

Background

The permanent magnet synchronous electric spindle is one of the core components of the high-precision numerical control machine tool, is a transmission structure form which combines a spindle motor and a machine tool spindle into a whole, and has the advantages of simple structure, high power factor, good low-speed performance, small loss and the like. Vector control realizes effective decoupling of the exciting current and the torque current of the high-speed electric spindle, and excellent dynamic performance can be obtained. The direct torque technology does not need rotation coordinate transformation in magnetic field orientation vector control, directly carries out stator flux linkage and electromagnetic torque, has a simple control system, and has obvious torque pulsation.

Disclosure of Invention

The invention provides a speed regulating system of a permanent magnet synchronous electric main shaft and a control method thereof, aiming at solving the defects of vector control and direct torque control, realizing a higher-performance driving control method of the permanent magnet synchronous electric main shaft by deeply analyzing the commonality of the vector control and the direct torque control and combining the advantages of the two controls, and being used for improving the quick response capability of the system and reducing the torque pulsation of the system.

The speed regulating system of the permanent magnet synchronous electric spindle according to the embodiment of the invention comprises: the main circuit comprises a power inverter circuit and a permanent magnet synchronous motor, an electric main shaft of the permanent magnet synchronous motor is connected with the power inverter circuit, and the control circuit comprises: the magnetic flux linkage control system comprises a rotating speed regulator, a magnetic flux linkage generator, a torque regulator, a magnetic flux linkage regulator, two current hysteresis comparators, a SVPWM (space vector pulse width modulation), a magnetic flux linkage observer and a voltage vector table, wherein the rotating speed regulator, the torque regulator and one of the current hysteresis comparators are connected with the voltage vector table in series, the magnetic flux linkage generator is connected on the rotating speed regulator in parallel, the magnetic flux linkage regulator is connected with the other current hysteresis comparator in series and then is arranged in parallel with the torque regulator, the magnetic flux linkage observer is connected between an electric main shaft and the voltage vector table and is connected with the two current hysteresis comparators and used for controlling the calculation of a stator magnetic flux linkage phase angle in current coordinate transformation and direct torque control, and the current hysteresis comparators are used for controlling the voltage vector switch table and further controlling torque and magnetic flux linkage.

The control method of the speed regulating system of the permanent magnet synchronous electric spindle according to the embodiment of the invention comprises the following steps: s1, taking the difference between the actual rotating speed and the rated rotating speed of the permanent magnet synchronous electric spindle as the given value of the rotating speed governor; s2, outputting the rotor flux linkage according to the flux linkage generating function, respectively passing through a torque regulator and a flux linkage regulator to obtain a sum, and comparing the sum with an actual value to obtain a current deviation; s3, generating a mark signal-1, 0 or 1 according to the current displacement comparator, and selecting a proper voltage vector by combining a stator flux linkage phase angle as the input of a switching table; and S4, determining the on-off of the power inverter circuit according to the switch table, outputting a corresponding voltage vector, and realizing the hybrid drive control of the permanent magnet synchronous electric spindle.

According to one embodiment of the present invention, the hybrid drive control combines vector control and direct torque control, the d-axis and q-axis currents of the electric spindle are generated by vector control, the hysteresis control of the excitation current and the torque current and the voltage vector table are generated by a direct torque control system.

According to one embodiment of the invention, the hybrid drive controlled current coordinate system transformation and stator flux phase angle are obtained from flux observers in combination with vector controlled and direct torque controlled flux observers.

According to one embodiment of the invention, the stator current is obtained by a vector control method.

According to one embodiment of the invention, the control vector of the voltage vector switch controls the stator current and thus the torque and flux linkage.

The invention has the technical effects that: the hybrid-drive-based control is adopted to replace the traditional vector control and direct torque control, so that the system has better quick response capability, and the torque and flux linkage are indirectly controlled through the voltage vector switch table, so that the problem of torque pulsation generated in a direct torque system is effectively inhibited.

Drawings

FIG. 1 is a schematic diagram of a permanent magnet synchronous electric spindle speed regulating system based on hybrid drive control according to the present invention;

FIG. 2 is a d-q coordinate diagram of the electric spindle;

fig. 3 is a control schematic diagram of stator flux linkage and electromagnetic torque.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

A speed control system of a permanent magnet synchronous electric spindle and a control method thereof according to an embodiment of the present invention will be described with reference to fig. 1 to 3.

Fig. 1 shows a speed control system of a permanent magnet synchronous electric spindle according to an embodiment of the present invention, including: the main circuit comprises a power inverter circuit and a permanent magnet synchronous motor, an electric main shaft of the permanent magnet synchronous motor is connected with the power inverter circuit, and the control circuit comprises: the magnetic flux linkage control system comprises a rotating speed regulator, a magnetic flux linkage generator, a torque regulator, a magnetic flux linkage regulator, two current hysteresis comparators, a SVPWM (space vector pulse width modulation), a magnetic flux linkage observer and a voltage vector table, wherein the rotating speed regulator, the torque regulator and one of the current hysteresis comparators are connected with the voltage vector table in series, the magnetic flux linkage generator is connected on the rotating speed regulator in parallel, the magnetic flux linkage regulator is connected with the other current hysteresis comparator in series and then is arranged in parallel with the torque regulator, the magnetic flux linkage observer is connected between an electric main shaft and the voltage vector table and is connected with the two current hysteresis comparators and used for controlling the calculation of a stator magnetic flux linkage phase angle in current coordinate transformation and direct torque control, and the current hysteresis comparators are used for controlling the voltage vector switch table and further controlling torque and magnetic flux linkage.

And the flux linkage observer of the hybrid drive control completes the current coordinate transformation of vector control and the stator flux linkage phase angle calculation of direct torque control.

The output currents of the two current hysteresis comparators are used for controlling the voltage vector switching table, so that the torque and flux linkage are indirectly controlled, and the torque pulsation problem in a direct torque control system is effectively suppressed.

Because the rotor of the permanent magnet synchronous electric spindle is asymmetric in magnetic, electric and other structures, the permanent magnet synchronous electric spindle is a time-varying, multivariable and strongly coupled nonlinear system in an ABC coordinate system, and the corresponding analysis and control of the system are difficult, so that the decoupling control of the electric spindle is realized by adopting the directional control of the magnetic field of the rotor under vector control.

The transformation formula from the ABC coordinate system to the d-q axis is as follows:

the decoupling of the stator current can be realized by using the formula (1).

The relationship of the vectors of the three-phase PMSM is shown in figure 2, and stator flux linkage is definedMagnetic pole linkage with rotorThe included angle therebetween is the torque angle delta.

From FIG. 2, the projection of the stator flux linkage on the d-q coordinate system can be found as

The stator flux linkage equation is

Thus, the stator current equation in the d-q coordinate system can be obtained according to the formula (2) and the formula (3) as

For a surface-mounted three-phase PMSM, the stator inductance satisfies L_d＝L_q＝L_sAt this time, the electromagnetic torque satisfies:

from the formula (4)

Is obtained by the formula (5) and the formula (6)

T_e＝p_nψ_fi_q (8)

When delta → 0, from the formulae (7) and (8)

ψ_s∝i_d (9)

T_e∝i_q (10)

By adopting the optimal scheme, the voltage vector switch table is controlled by utilizing the output current difference value of the current hysteresis comparator, so that the control of the torque and the flux linkage is indirectly realized, the torque pulsation is effectively inhibited, and the dynamic performance of the system is improved.

It is generally desirable that the stator flux linkage vector locus be circular, which can be achieved by selecting an appropriate stator voltage vector, as shown in FIG. 3, which is generally setInstruction value ofIs a circle and then is pairedPerforming hysteresis control toApproximationThe space complex plane is divided into 6 intervals of I, II, … and VI, the width of each interval is 60 electrical degrees, and the dotted lines are interval intervals, as shown in figure 3.

The values of the switch table are shown in table 1.

TABLE 1 Voltage vector switching Table

And (3) selecting the switching voltage vector of six intervals according to the table 1 to realize indirect control of the torque and the flux linkage. In the table, the positive and negative of the sum are determined according to the output of the current hysteresis comparator.

The permanent magnet synchronous electric main shaft speed regulating system based on hybrid drive control combines vector control and direct torque control, is easy to realize, has excellent dynamic performance, and effectively inhibits torque pulsation generated by the traditional direct torque control system.

The above embodiments are preferred embodiments of the present invention, and those skilled in the art can make variations and modifications to the above embodiments, therefore, the present invention is not limited to the above embodiments, and any obvious improvements, substitutions or modifications made by those skilled in the art based on the present invention are within the protection scope of the present invention.