CN1713490A - Numerical Control Servo System and Control Method for Bearingless Permanent Magnet Synchronous Motor - Google Patents

Abstract

The three degree of freedom radial-axial direction mixing magnetic bearing, and two degree of freedom bearingless permanent magnet synchronous motor are used to compose 5 degree of freedom bearingless permanent magnet synchronous motor digital-control servosystem. Three independent PID linear controllers are used to make independent control. Through adjusting control parameter of PID controllers, implements steady operation of the mixing magnetic bearing. The hall sensor is used to detect the size of magnetic field of rotator, and directional control strategy based on rotator field is adopted to make dynamic decoupling control. Through adjusting parameter of two PI controller in location control ring, ensures redial direction suspension system of bearingless motor has good dynamical and static property. Through adjusting parameters of three PI controller in rotating speed control ring, ensures the rotating speed has good response property.

Description

Numerical Control Servo System and Control Method for Bearingless Permanent Magnet Synchronous Motor

technical field

The present invention is a structure and control method of a bearingless permanent magnet synchronous motor numerical control servo control system, which is suitable for many special electrical transmission fields such as sealed pumps, high-speed or ultra-high-speed numerical control machine tools, industrial robots, aerospace, life sciences, etc., especially non-contact, No need for lubrication and no wear, etc., it is used in special occasions such as vacuum technology, pure clean room and aseptic workshop, and the transmission of corrosive media or very pure media, and belongs to the technical field of electric drive control equipment.

Background technique

The traditional five-degree-of-freedom bearingless permanent magnet motor (except the rotational degree of freedom) is composed of two two-degree-of-freedom bearingless permanent magnet synchronous motor units and one axial magnetic bearing. The mechanical structure of the motor is quite complicated, the axial direction of the rotor is very long, and the critical speed of the motor is greatly limited, especially the control system is relatively large. Two two-degree-of-freedom bearingless permanent magnet motor units require four three-phase inverter drive circuits, and the axial Magnetic bearings require a switching power amplifier, and two two-degree-of-freedom bearingless motor units need to be well coordinated and controlled. The control system is too complicated to be applied in practice.

In order to essentially simplify the complexity of the mechanical structure and control of the five-degree-of-freedom bearingless permanent magnet synchronous motor and realize the high-speed rotation and control of the suspended rotor, it is necessary to adopt a new mechanical structure and control method to develop a bearingless motor with a compact structure and simple control. Structure and control method of CNC servo system for permanent magnet synchronous motor.

There are no relevant patents and documents at home and abroad.

Contents of the invention

The purpose of the present invention is to change the structure of the traditional five-degree-of-freedom bearingless permanent magnet synchronous motor, and design a five-degree-of-freedom bearingless motor composed of a three-degree-of-freedom radial-axial hybrid magnetic bearing and a two-degree-of-freedom bearingless permanent magnet synchronous motor The prototype body of the permanent magnet synchronous motor (except the rotation degree of freedom) adopts a rotor field-oriented control strategy based on the double closed-loop control of the two-degree-of-freedom bearingless permanent-magnet synchronous motor, and the three-degree-of-freedom magnetic bearing adopts three independent position PID control device to control. The structure of the motor is simple and the performance of the control system is excellent. This type of bearingless permanent magnet synchronous motor is used in many special electrical transmission fields such as sealed pumps, high-speed or ultra-high-speed CNC machine tools, industrial robots, aerospace, life sciences, etc., especially for non-contact, non-lubricating and non-wearing characteristics. It is widely used in electrical drive systems for special occasions such as vacuum technology, pure clean rooms and aseptic workshops, and the transmission of corrosive media or very pure media.

The solution of the present invention is: the mechanical structure of the numerical control servo system of the five-degree-of-freedom bearingless permanent magnet synchronous motor is composed of a two-degree-of-freedom bearingless permanent-magnet synchronous motor and a three-degree-of-freedom radial-axial hybrid magnetic bearing. The three-degree-of-freedom radial-axial hybrid magnetic bearing is composed of an axial stator, an axial control coil, a rotor core, a radial control coil, a radial stator and an annular permanent magnet. The gaps between the rotor core and the axial stators on both sides are regarded as two axial air gaps; the gaps between the rotor iron core and the radial stator poles are regarded as four radial air gaps. The axial magnetic circuit and the radial magnetic circuit respectively pass through the corresponding stator, air gap and rotor to form a complete magnetic flux circuit. The composite magnetic flux at the axial air gap and the radial air gap is synthesized by the permanent magnet bias magnetic flux and the control magnetic flux, and the change of the composite magnetic flux can change the radial or axial levitation force.

The three-degree-of-freedom radial-axial magnetic bearing control system is composed of a linear closed-loop controller, a switching power amplifier, a three-degree-of-freedom magnetic bearing executive solenoid control coil and a displacement sensor, and the radial and axial displacement of the magnetic bearing is detected by the displacement sensor Compared with the given reference quantity, adjust the parameters of the position PID controller respectively, generate corresponding control signals, generate control current through the switching power amplifier, drive the electromagnet coils respectively, generate electromagnetic force, and realize three-degree-of-freedom radial-axial The magnetic bearing rotor is suspended in an equilibrium position.

The two-degree-of-freedom bearingless permanent magnet motor is composed of a stator core, a rotor, a permanent magnet, a stainless steel collar, a motor winding, a radial force winding, and a rotating shaft. The radial displacement of the rotor is detected by a displacement sensor, and the speed is detected by a Hall sensor.

The two-degree-of-freedom bearingless motor control system consists of a radial position control subsystem and a speed control subsystem, and both subsystems are controlled by double closed loops. The inner loop of the position subsystem is composed of a current closed-loop controller, two coordinate transformations, a voltage-type three-phase inverter and a current sensor. The actual current in the suspension force winding is detected by the current sensor, and the current PI controller in the current closed-loop controller is adjusted. parameters to realize current closed-loop control; the outer loop is composed of a position closed-loop controller, an inner loop, a two-degree-of-freedom bearingless motor, and an eddy current displacement sensor. The rotor position can be controlled by adjusting the parameters of the linear closed-loop controller. The speed loop subsystem is also composed of an inner loop current loop and an outer loop speed loop. The inner loop is composed of a current closed loop controller, two coordinate transformations, a voltage type three-phase inverter, and a current sensor. The current sensor detects the voltage in the motor winding. The actual current is realized by adjusting the current PI controller in the current closed-loop controller to realize the current closed-loop control; the outer loop is composed of a speed closed-loop controller, an inner loop, a two-degree-of-freedom bearingless permanent magnet synchronous motor, and a Hall sensor. By adjusting the speed PI The parameters of the controller are used to perform closed-loop control on the speed of the motor. By measuring the magnetic field of the rotor, the rotor field-oriented control strategy is used to control the dynamic decoupling between the rotor displacement and speed.

The principle of the invention is to change the structure of the traditional five-degree-of-freedom bearingless permanent magnet synchronous motor, and design a five-degree-of-freedom non-magnetic Bearing permanent magnet synchronous motor (except rotation degree of freedom) CNC servo system prototype body. A nonlinear dynamic decoupling control of a two-degree-of-freedom bearingless permanent magnet synchronous motor is carried out using a rotor field-oriented control strategy. The position of the three-degree-of-freedom magnetic bearing is independently controlled by three position controllers, and the stable operation of the three-degree-of-freedom hybrid magnetic bearing is realized by adjusting the parameters of the position PID controller. For the two-degree-of-freedom bearingless permanent magnet synchronous motor, the position of the rotor magnetic field is detected by the Hall sensor, and the directional control strategy based on the rotor magnetic field is used for decoupling control. By adjusting the parameters of the PI controller in the speed control loop, it is ensured that the speed has a good Response performance; By adjusting the parameters of the PI controller and the PID controller in the position control loop, it is ensured that the radial suspension system of the bearingless motor has good dynamic and static performance.

The bearingless permanent magnet synchronous motor numerical control servo system developed by this scheme is compatible with the permanent magnet synchronous motor supported by three magnetic bearings and the traditional five-degree-of-freedom bearingless permanent magnet synchronous motor (two two-degree-of-freedom bearingless permanent magnet synchronous motor units) Compared with an axial magnetic bearing), it has the following advantages: ①The system is composed of 2 parts, the structure is compact, the length of the rotor is greatly shortened, the speed and power of the motor can be further improved, and miniaturization can be realized; ②The control system The structure is simple, there is no need to consider the coordinated control between two two-degree-of-freedom bearingless permanent magnet synchronous motor units, and the control algorithm is easy to implement.

The advantages of the present invention are:

1. The mechanical structure of the bearingless permanent magnet synchronous motor CNC servo system is more reasonable and practical. It gets rid of the shortcomings of the permanent magnet synchronous motor supported by three magnetic bearings and the traditional five-degree-of-freedom bearingless permanent magnet synchronous motor with complex structure, low critical speed and overly complicated control system.

2. The joint control of the radial-axial three-degree-of-freedom magnetic bearing is cleverly realized. Compared with the combination of two-degree-of-freedom radial magnetic bearing and single-degree-of-freedom axial magnetic bearing, under the same power or supporting force, the axial length of the rotor is greatly reduced; or the system power can be made more in the same volume Higher, the suspension force can be made bigger.

3. The three-degree-of-freedom radial-axial hybrid magnetic bearing has a compact structure and adopts permanent magnetic bias, which reduces the volume and power consumption of the power amplifier and reduces the manufacturing cost.

4. The two-degree-of-freedom bearingless permanent magnet synchronous motor is based on the rotor field-oriented control strategy, the position subsystem and the speed subsystem adopt the rotor field-oriented control, the magnetic field detection is simple and reliable, and the control method is easy to implement.

5. The magnetic bearing switching power amplifier and the voltage-type three-phase inverter of the bearingless motor are mature in technology and low in cost, which reduces the overall cost of the system.

6. The digital control part of the three-degree-of-freedom radial-axial hybrid magnetic bearing and the two-degree-of-freedom bearingless permanent magnet synchronous motor share a DSP digital signal processor, except for the switching power amplifier, voltage-type three-phase inverter, sensors and interfaces In addition to the circuit, other control links are realized by software programming, which increases the flexibility and reliability of the system.

7. The mechanical structure of the five-degree-of-freedom bearingless permanent magnet synchronous motor designed by the present invention has a compact structure, and this structure can be used for other types of bearingless motors (such as bearingless AC asynchronous motors, bearingless reluctance motors, bearingless switched reluctance motor).

Description of drawings

Figure 1 is a mechanical structure diagram of a five-degree-of-freedom bearingless permanent magnet synchronous motor, which is composed of a three-degree-of-freedom radial-axial hybrid magnetic bearing and a two-degree-of-freedom bearingless permanent magnet synchronous motor. Specifically, it consists of: radial auxiliary bearing (1), nine displacement sensor probes (2), rotating shaft (3), rear end cover (4), magnetic bearing rotor core (5), magnetic bearing axial stator (6), Magnetic bearing axial control coil (7), magnetic bearing annular permanent magnet (8), magnetic bearing radial stator (9), magnetic bearing radial control coil (10), 2 displacement sensor brackets (11), 2 positioning Sleeve (12), stator of bearingless permanent magnet synchronous motor (13), rotor of bearingless permanent magnet synchronous motor (14), 4 Hall sensors for speed detection of bearingless motor (15), cylinder casing (16), cylinder Tube inner sleeve (17), front end cover (18), auxiliary bearing (19).

Fig. 2 is a structural schematic diagram of a five-degree-of-freedom bearingless permanent magnet synchronous motor, which includes a two-degree-of-freedom bearingless permanent-magnet synchronous motor (21) and a three-degree-of-freedom radial-axial hybrid magnetic bearing (22).

Fig. 3 is a structural schematic diagram of a radial stator (9) and an axial stator (6) of a three-degree-of-freedom radial-axial hybrid magnetic bearing.

Fig. 4 is a structural schematic diagram of the radial coil (10) and the axial coil (7) of a three-degree-of-freedom radial-axial hybrid magnetic bearing. coil.

Figure 5 is a magnetic circuit diagram of the axial magnetic circuit of a three-degree-of-freedom radial-axial hybrid magnetic bearing, and the gaps between the rotor core (5) and the axial stators (6) on both sides are used as two axial air gaps , the synthetic flux at the axial air gap is synthesized by the permanent magnet bias flux φ _PM and the control flux φ _ZEM respectively, and the change of the synthetic flux changes the axial levitation force.

Fig. 6 is the magnetic circuit diagram of the radial magnetic circuit of the three-degree-of-freedom radial-axial hybrid magnetic bearing, and the gaps between the rotor core (5) and the four magnetic poles of the radial stator (9) serve as four radial gas Gap. The radial magnetic circuit respectively passes through the radial stator (9), the air gap and the rotor iron core (5) to form a complete magnetic flux circuit. The synthetic flux at the radial air gap is synthesized by the permanent magnet bias flux φ _PM and the control flux (φ _XEM , φ _YEM ) respectively, and the change of the synthetic flux at the air gap can change the radial or axial levitation force .

Fig. 7 is a block diagram of a three-degree-of-freedom radial-axial hybrid magnetic bearing control system. It consists of a three-degree-of-freedom radial-axial hybrid magnetic bearing (22), a displacement sensor (50), a linear closed-loop controller (30), and a switching power amplifier (40). The position of the rotor is detected by the displacement sensor (50), compared with a given reference position signal, and the PID position control is realized through software programming inside the DSP.

Fig. 8 is a structural diagram of a double-closed-loop control system for a two-degree-of-freedom bearingless permanent magnet synchronous motor. Both subsystems are controlled by a double closed-loop, and the inner loop of the position subsystem is composed of a current closed-loop controller (70), a coordinate transformation (81, 82), a voltage-type three-phase inverter (91), and a current sensor (101); The outer ring is composed of a position closed-loop controller (60), an inner ring, a two-degree-of-freedom bearingless permanent magnet synchronous motor (21), and eddy current displacement sensors (54, 55).

The speed loop subsystem is also composed of an inner loop current loop and an outer loop speed loop. The current inner loop consists of a current closed-loop controller (74), coordinate transformation (83, 84), voltage-type three-phase inverter (92), and a current sensor (102) Composition. The outer loop is composed of a closed-loop controller (64), a current inner loop, a two-degree-of-freedom bearingless permanent magnet synchronous motor (21), and a Hall sensor (15). By adjusting the parameters of the speed PI controller (64), the motor closed-loop control of the speed.

Fig. 9 is a schematic diagram of the composition of the control system of the device of the present invention using DSP as the structure and control method of the numerical control servo system of the bearingless permanent magnet synchronous motor. Wherein the DSP controller 110 .

Fig. 10 is the system software block diagram of realizing the present invention with DSP as controller CPU.

Detailed ways

Embodiments of the present invention are:

The control method adopted is a five-degree-of-freedom bearingless permanent magnet synchronous motor CNC servo system prototype body composed of a two-degree-of-freedom bearingless permanent magnet synchronous motor (21) and a three-degree-of-freedom radial-axial hybrid magnetic bearing (22). , using a linear closed-loop controller (30) to control the radial-axial position of the three-degree-of-freedom hybrid magnetic bearing; adjusting the control parameters of the position PID controller (31, 32, 33) to realize the three-degree-of-freedom radial-axial hybrid The magnetic bearing works stably; the Hall sensor (15) is used to detect the size of the rotor magnetic field, and the radial displacement and the motor speed are dynamically decoupled and controlled using a rotor field-oriented control strategy based on a two-degree-of-freedom bearingless permanent magnet synchronous motor; by adjusting the position control The parameters of two PI controllers (71, 72) and two PID controllers (61, 62) in the ring realize the good dynamic and static performance of the two-degree-of-freedom bearingless permanent magnet synchronous motor radial suspension system; by adjusting The parameters of the three PI controllers (64, 75, 76) in the speed control loop ensure that the speed has good response performance.

The specific implementation is divided into the following 9 steps:

1. The body of the bearingless permanent magnet synchronous motor is composed of a two-degree-of-freedom bearingless permanent-magnet synchronous motor (21) and a three-degree-of-freedom radial-axial hybrid magnetic bearing (22) in the inner sleeve of the cylinder;

The three-degree-of-freedom radial-axial hybrid magnetic bearing (22) at the right end is fixed in the rear end cover (4) by the radial auxiliary bearing (1); the axial displacement sensor probe (2) is fixed in the rear end cover (4) on the center of the rotating shaft (3) to detect the axial displacement of the rotating shaft (3); the four radial displacement sensor probes (2) of the magnetic bearing are fixed on the sensor bracket (11), and the sensor bracket (11) is fixed on Close to the side of the magnetic bearing; the magnetic bearing rotor core (5) is fixed together with the rotating shaft (3), and is made of laminated silicon steel sheet materials; the axial stator (6) of the magnetic bearing surrounds the radial stator (9) and The annular permanent magnet (8), the annular permanent magnet (8) is installed between the radial stator (9) of the magnetic bearing and the axial stator (6) of the magnetic bearing; the radial control coil (10) of the magnetic bearing is respectively wound in the radial direction On the four magnetic poles evenly distributed along the circumference of the stator (9), the coils on the two opposite magnetic poles are connected in series to form a radial degree of freedom control coil, which provides radial control magnetic flux; the axial control coil of the magnetic bearing ( 7) Inside the axial stator of the magnetic bearing, on both sides of the radial stator (9) of the magnetic bearing and the permanent magnet (8) evenly distributed, two coils are connected in series;

In the two-degree-of-freedom bearingless permanent magnet synchronous motor (21) at the left end, the surface of the bearingless permanent magnet synchronous motor rotor (14) is equipped with permanent magnet material neodymium iron boron to make a permanent magnet with a pole pair number of 2. The steel cylinder is fixed, and the motor rotor (14) is installed on the rotating shaft (3); the stator (13) of the bearingless permanent magnet synchronous motor is the stator of a standard permanent magnet synchronous motor, and two sets of windings are stacked in the stator slot, and the two sets of windings The number of pole pairs is ±1; the four radial displacement sensor probes (2) of the bearingless permanent magnet synchronous motor are installed on the sensor bracket (11) close to the front end cover (18), and the radial displacement sensor probes (2) are measured by differential measurement. For the displacement of degrees of freedom, the sensor bracket (11) is fixed on the left end of the bearingless permanent magnet synchronous motor (21); 4 Hall sensors (15) that measure the rotating speed are fixed on the sensor bracket (11); Auxiliary bearing (19) is as the auxiliary supporting bearing of bearingless permanent magnet synchronous motor.

Three-degree-of-freedom radial-axial hybrid magnetic bearing (22), two-degree-of-freedom bearingless permanent magnet synchronous motor (21), two positioning sleeves (12), and two sensor brackets (11) are all installed in the cylinder In the sleeve 17, the cylinder is composed of an inner sleeve 17 and an outer sleeve 16, and is used to support a three-degree-of-freedom radial-axial hybrid magnetic bearing stator and a two-degree-of-freedom bearingless permanent magnet synchronous motor stator. There is a spiral channel between them, through which water cools the five-degree-of-freedom bearingless permanent magnet synchronous motor system.

The control system of the three-degree-of-freedom radial-axial hybrid magnetic bearing (22) consists of a linear closed-loop controller (30), a switching power amplifier (40), a three-degree-of-freedom radial-axial magnetic bearing (22), and a displacement sensor ( 50) connected successively to form.

The control system of the two-degree-of-freedom bearingless permanent magnet synchronous motor (21) is composed of a radial position control subsystem and a speed control subsystem, and the inner loop of the position subsystem is composed of a current closed-loop controller (70), coordinate transformation (81, 82) , a voltage-type three-phase inverter (91), a current sensor (101), etc.; the outer ring is composed of a position closed-loop controller (60), an inner ring, a two-degree-of-freedom bearingless permanent magnet synchronous motor (21), and a displacement sensor ( 54, 55) composition. The speed loop subsystem consists of a current inner loop and a speed outer loop. The current inner loop consists of a current closed-loop controller (74), coordinate transformation (83, 84), voltage-type three-phase inverter (92), and a current sensor (102). etc., the outer ring is composed of a speed closed-loop controller (63), an inner current ring, a two-degree-of-freedom bearingless permanent magnet synchronous motor (21), a Hall sensor (15) and the like.

A two-degree-of-freedom bearingless asynchronous motor is used instead of the two-degree-of-freedom bearingless permanent magnet synchronous motor to form a five-degree-of-freedom bearingless asynchronous motor CNC servo system; specifically, the bearingless asynchronous motor applies the stator and squirrel-cage rotor of a standard asynchronous motor Structure, two sets of windings are stacked in the stator slot, the number of pole pairs of the two sets of windings is ±1, and the photoelectric encoder disc is installed at one end of the shaft.

2. Displacement detection. The eddy current sensor is used to detect the displacement of 5 degrees of freedom in the axial and radial directions. One eddy current sensor is used in the axial direction, and 8 eddy current sensors are used in the radial direction to perform differential detection in the x direction and y direction respectively, so as to obtain accurate position signals, which are processed by the interface circuit to make them appear in the DSP A/D Within the range of the input signal, the built-in sampling/holding circuit of DSP performs signal acquisition and processing on it.

3. Speed detection. 4 Hall sensors are used to differentially detect and process the rotor magnetic field to obtain the magnetic field rotation angle and the motor speed. Four Hall sensors (15) for measuring the rotational speed are fixed on the sensor bracket (11), close to the rotor of the motor, and indirectly measure the rotational speed of the motor by measuring the magnetic field of the rotor; a photoelectric encoder can also be installed on one end of the rotating shaft to measure the rotational speed of the motor. Measure the speed of the motor.

4. Magnetic bearing switching power amplifier. Using traditional switching power amplifier, it has the characteristics of fast response, simple structure and high efficiency. The control signal output by the DSP is directly used as the driving signal of the switching power amplifier, which is amplified to generate a control current, and the control current generates an active magnetic levitation force in the executive magnet to keep the rotor in a balanced position.

5. Bearingless motor voltage type three-phase inverter. The intelligent power module IPM is used as the main inverter circuit, and the DSP outputs three-phase PWM signals to control the voltage-type three-phase inverter. The DSP detects the inverter fault signal and handles the fault.

6. Construct a three-degree-of-freedom radial-axial hybrid magnetic bearing control system. The three-degree-of-freedom magnetic bearing position control system consists of a linear closed-loop controller, a switching power amplifier, a three-degree-of-freedom radial-axial magnetic bearing actuator electromagnet, and a displacement sensor. The displacement sensor detects the radial and axial displacement of the magnetic bearing and The given displacement reference value is compared, the parameters of the position PID controller are adjusted respectively, the corresponding control signal is generated, the control current is generated through the switching power amplifier, and the electromagnet coil is respectively driven to generate electromagnetic force to realize the three-degree-of-freedom magnetic bearing rotor levitation in a balanced position.

For three-degree-of-freedom radial-axial magnetic bearing position control, the displacement sensor (51, 52, 53) detects the radial and axial displacement of the magnetic bearing and compares it with a given displacement reference value, and adjusts the position PID controller respectively. The parameters of (31, 32, 33) generate corresponding control signals, generate control currents through switching power amplifiers (41, 42, 43), and respectively drive the electromagnet coils of the three-degree-of-freedom radial-axial magnetic bearing (22) (10, 7), generating electromagnetic force to realize the suspension of the three-degree-of-freedom radial-axial magnetic bearing rotor at the equilibrium position.

7. Construct a two-degree-of-freedom bearingless permanent magnet synchronous motor control system. The radial position control subsystem and the speed control subsystem that make up the two-degree-of-freedom bearingless permanent magnet synchronous motor control system are controlled by double closed loops; the actual current in the suspension force winding is detected by the current sensor (101), and the coordinate transformation ( 81) Computation and processing, by adjusting the parameters of the PI controller (71, 72) in the current closed-loop controller (70), the current closed-loop control is realized; by adjusting the parameters of the position PID controller (61, 62), the radial direction of the rotor is realized. The position is controlled; the actual current in the motor winding of the bearingless permanent magnet synchronous motor (21) is detected by the current sensor (102), and the current is realized by adjusting the parameters of the PI controller (75, 76) in the current closed-loop controller (74). Closed-loop control; by adjusting the parameters of the speed PI controller (64), the speed of the motor can be closed-loop controlled;

将测量到悬浮力绕组两相电流实际值i2u(s)、i2v(s)

→计算

→Clark变换→Park变换→再与两相旋转D-Q坐标系中电流的命令值

比较→经过PI控制器(71，72)产生电压命令值

→逆Clark变换→逆Park变换产生三相电压命令值

和 →经过电压型三相逆变器(91)产生三相悬浮力绕组驱动电压

和

→实现转子稳定悬浮在平衡位置。根据检测的转子磁场位置角γ，计算出电机实际角速度ω_m，与角速度命令值

比较后，经过PI控制器(64)产生电流命令值

采用磁场定向控制 $i_{1d}^{\left(F\right)*}=0$ 再采用与位置内环相似的变换和控制方法，即可以实现对转速的独立控制。The dynamic decoupling control between displacement and speed adopts the rotor field-oriented control strategy for decoupling. By detecting the position angle γ of the rotor magnetic field, the two-phase rotating DQ coordinates (indicated by "F" in the upper right corner of the variable in Figure 8) Transform the quantity of the two-phase static dq coordinates into the two-phase static dq coordinates (indicated by "S" in the upper right corner of the variable in Figure 8), and transform the measured suspension force and the quantity in the motor winding from the two-phase static dq coordinates to the two-phase rotating DQ coordinates. Dynamic decoupling control can be realized. For the position control subsystem, the angle between the two-phase rotating DQ coordinate system relative to the two-phase stationary dq coordinate system γ _B = γ+ _B ; for the speed control subsystem, the two-phase rotating DQ coordinate system relative to the two-phase stationary The included angle between the dq coordinate systems γ _M =γ+ _M ,  _B ,  _M are the electrical angles between the suspension force winding A-phase winding axis and the motor winding A-phase winding axis and the stationary d-axis respectively. The specific decoupling method is to compare the detected radial displacement of the rotor X and Y with the given command values X ^* and Y ^* in the position loop control subsystem, and generate current through the PID controller (61, 62) command value

The actual value i2u(s) and i2v(s) of the two-phase current of the suspension force winding will be measured

→ calculate

→Clark transformation→Park transformation→and the command value of the current in the two-phase rotating DQ coordinate system

Compare → generate voltage command value through PI controller (71, 72)

→ Inverse Clark transformation → Inverse Park transformation generates three-phase voltage command value

and →Through the voltage-type three-phase inverter (91) to generate three-phase suspension force winding driving voltage

and

→Realize the stable suspension of the rotor in the equilibrium position. According to the detected rotor magnetic field position angle γ, calculate the actual angular velocity ω _m of the motor, and the angular velocity command value

After comparison, generate current command value through PI controller (64)

field oriented control $i_{1d}^{\left(f\right)*}=0$ Then adopt the transformation and control method similar to the position inner loop, that can realize the independent control of the speed.

8. Build the DSP controller (110). TI's TMS320LF2407 DSP digital signal processor is used as the CPU of the DSP controller. This CPU has a fast calculation speed, a single instruction only takes 33ns, a 10-bit high-speed A/D converter with a built-in sample/hold circuit, and a PWM signal event management module. By expanding the D/A converter, it can meet the magnetic Bearing control requirements.

Magnetic bearing control part: DSP controller realizes the acquisition of radial-axial 3-degree-of-freedom displacement sensor signals through software programming, linear closed-loop controller operation processing, and outputs corresponding control signals to realize three-degree-of-freedom radial-axial Closed-loop control of hybrid magnetic bearings.

For the part of the two-degree-of-freedom bearingless permanent magnet synchronous motor: the DSP controller realizes the radial two-degree-of-freedom displacement, levitation force, motor winding current, and signal acquisition of the motor speed through software programming. For the position subsystem, through the position PID control (61, 62) operation, coordinate transformation (81) operation, current closed-loop controller (71, 72) operation, coordinate transformation (82) operation and processing, output PWM signal to suspension force winding voltage type three-phase inverter ( 91). For the rotational speed subsystem, after speed PI controller (64) calculation, coordinate transformation (83) calculation, current closed-loop controller (75, 76) calculation, coordinate transformation (84) calculation and processing, the PWM signal is output to the suspension force A winding voltage type three-phase inverter (92).

9. Control parameter adjustment.

1) The magnetic bearing current PI controller is designed by using the proportional-integral controller PI in linear theory, pole configuration or quadratic index optimization. Adjust the parameters of two current PI controllers to realize the closed-loop control of the inner loop current. The magnetic bearing position PID controller is designed by the method of proportional integral differential controller PID in linear theory, pole configuration or quadratic index optimization, and adjusts the parameters of the three position PID controllers to realize the magnetic bearing suspension.

2) The PI controller in the two-degree-of-freedom bearingless permanent magnet synchronous motor control system is designed by using the proportional-integral PI in linear theory, pole configuration or quadratic index optimization. After adjusting the stable suspension of the position subsystem, the parameters of the inner loop current PI controller of the speed subsystem are adjusted, and then the parameters of the outer loop PI controller of the speed are adjusted to realize the stable suspension and rotation of the two-degree-of-freedom bearingless permanent magnet synchronous motor.

The above description is only used to illustrate the present invention, not to limit it.

Claims (9)

1, bearing-free permanent magnet synchronous motor digital control servo system is characterized in that the bearing-free permanent magnet synchronous motor body is to be made of two degrees of freedom bearing-free permanent magnet synchronous motor (21) and Three Degree Of Freedom radial-axial hybrid magnetic bearing (22) in the cover in cylinder barrel;

The Three Degree Of Freedom radial-axial hybrid magnetic bearing (22) of right-hand member is fixed in the rear end cap (4) by auxiliary bearing (1) radially; Shaft position sensor probe (2) is fixed on the rear end cap (4), be in rotating shaft (3) in the heart, detect the axial displacement of rotating shaft (3); 4 radial displacement transducer probes (2) of magnetic bearing are fixed on the sensor stand (11), and sensor stand (11) is fixed on the side near magnetic bearing; The same rotating shaft of magnetic bearing rotor core (5) (3) is fixed together, and is overrided to form by silicon steel material; The axial stator of magnetic bearing (6) is surrounded radial stator (9) and annular permanent magnet (8), and annular permanent magnet (8) is installed between the axial stator (6) of magnetic bearing radial stator (9) and magnetic bearing; Magnetic bearing radially control coil (10) respectively around radial stator (9) along on equally distributed four magnetic poles of circumference, it is a radially control coil of the degree of freedom that the coil on 2 relative magnetic poles is in series, and provides and radially controls magnetic flux; The axial control coil (7) of magnetic bearing is in magnetic bearing axial stator inboard, equally distributed magnetic bearing radial stator (9) and permanent magnet (8) both sides, 2 coils series connection;

In the two degrees of freedom bearing-free permanent magnet synchronous motor (21) of left end, the permanent magnetic material neodymium iron boron is equipped with on bearing-free permanent magnet synchronous motor rotor (14) surface, and to make number of pole-pairs be 2 permanent magnet, the permanent magnet outside is fixed with steel cylinder, and rotor (14) is contained in the rotating shaft (3); The stator of bearing-free permanent magnet synchronous motor (13) is applied mechanically the stator of standard permagnetic synchronous motor, laminates 2 cover windings in the stator slot, and the numbers of pole-pairs of two cover windings are ± 1 relation; 4 radial displacement transducer probes (2) of bearing-free permanent magnet synchronous motor are installed near on the sensor stand (11) of front end housing (18), adopt the radially binary displacement of variate, sensor stand (11) is fixed on the left end of bearing-free permanent magnet synchronous motor (21); Be provided with 4 Hall elements (15) of measuring rotating speed and be fixed on sensor stand (11); The aiding support bearing of auxiliary bearing (19) as bearing-free permanent magnet synchronous motor is housed in the front end housing.

2, bearing-free permanent magnet synchronous motor digital control servo system according to claim 1 is characterized in that the control system of Three Degree Of Freedom radial-axial hybrid magnetic bearing (22) constitutes by linear closed-loop controller (30), switch power amplifier (40), Three Degree Of Freedom radial-axial magnetic bearing (22), displacement transducer (50) are continuous successively.

3, according to the described bearing-free permanent magnet synchronous motor digital control servo system of claim 1, the control system that it is characterized in that two degrees of freedom bearing-free permanent magnet synchronous motor (21) is made of radial position control subsystem and speed control subsystem, ring is by current closed-loop controller (70), coordinate transform (81,82), voltage-type three-phase inverter (91), current sensor formations such as (101) in the location subsystem; Outer shroud is made of position closed loop controller (60), interior ring, two degrees of freedom bearing-free permanent magnet synchronous motor (21), displacement transducer (54,55).The speed ring subsystem is made of current inner loop and speed outer shroud, current inner loop is by current closed-loop controller (74), coordinate transform (83,84), voltage-type three-phase inverter (92), current sensor formations such as (102), outer shroud is by speed closed loop controller (63), current inner loop, two degrees of freedom bearing-free permanent magnet synchronous motor (21), Hall element formations such as (15).

4, bearing-free permanent magnet synchronous motor digital control servo system according to claim 1, it is characterized in that 4 Hall elements (15) of measuring rotating speed are fixed on the sensor stand (11), near rotor,, measure rotating speed of motor indirectly by measuring the magnetic field size of rotor; Also can adopt photoelectric encoder to be installed in one of rotating shaft and bring in the measurement rotating speed of motor.

5, bearing-free permanent magnet synchronous motor digital control servo system according to claim 1 is characterized in that cylinder barrel is made of interior cover (17) and overcoat (16), has the spiral raceway groove to electric system water flowing cooling between two-layer.

6, bearing-free permanent magnet synchronous motor digital control servo system according to claim 1, it is characterized in that adopting two degrees of freedom not have the bearing asynchronous machine and replace described two degrees of freedom bearing-free permanent magnet synchronous motor, constitute five degrees of freedom without bearing asynchronous machine digital control servo system; Specifically be stator and the cage rotor structure that no bearing asynchronous machine is applied mechanically the standard asynchronous motor, laminate two cover windings in stator slot, the number of pole-pairs of two cover windings is ± 1 relation, adopts photoelectric coded disk to be installed in an end of rotating shaft.

7, the control method of bearing-free permanent magnet synchronous motor digital control servo system, it is characterized in that constituting permanent-magnet synchronous motor with five degrees of freedom without bearing digital control servo system model machine body, adopt the position of linear closed-loop controller (30) control three freedom degree mixed magnetic bearing radial-axial by two degrees of freedom bearing-free permanent magnet synchronous motor (21), Three Degree Of Freedom radial-axial hybrid magnetic bearing (22) etc.; Adjust the Control Parameter of position PID controller (31,32,33), realize Three Degree Of Freedom radial-axial hybrid magnetic bearing steady operation; Utilize Hall element (15) detection rotor magnetic field size, adopt based on rotor field-oriented control strategy radially displacement and motor speed carry out dynamic Decoupling Control of Load Torque two degrees of freedom bearing-free permanent magnet synchronous motor; By the parameter of 2 PI controller parameters (71,72) and 2 PID controllers (61,62) in the adjustment Position Control ring, realize the good dynamic and static state performance of two degrees of freedom bearing-free permanent magnet synchronous motor radial suspension system; By adjusting the parameter of 3 PI controllers (64,75,76) in the rotating speed control ring, guarantee that rotating speed has good response performance.

8, the control method of bearing-free permanent magnet synchronous motor digital control servo system according to claim 7, it is characterized in that to Three Degree Of Freedom radial-axial magnetic bearing Position Control be by displacement transducer (51,52,53) detecting radial and axial displacement of magnetic bearing and given displacement reference value compares, adjust position PID controller (31 respectively, 32,33) parameter, produce control signal corresponding, through switch power amplifier (41,42,43) produce Control current, drive the electromagnet coil (10,7) of Three Degree Of Freedom radial-axial magnetic bearing (22) respectively, produce electromagnetic force, realize that Three Degree Of Freedom radial-axial magnetic bearing rotor is suspended in the equilbrium position.

9, the control method of bearing-free permanent magnet synchronous motor digital control servo system according to claim 7 is characterized in that radial position control subsystem and the speed control subsystem of forming two degrees of freedom bearing-free permanent magnet synchronous motor control system all adopt two closed loops to control; By the actual current in current sensor (101) the detection suspending power winding,,, realize current closed-loop control by adjusting PI controller (71,72) parameter in the current closed-loop controller (70) through coordinate transform (81) computing and processing; By adjusting the parameter of position PID controller (61,62), realize the rotor radial position is controlled; By the actual current in current sensor (102) detection bearing-free permanent magnet synchronous motor (21) motor windings,, realize current closed-loop control by adjusting the parameter of PI controller (75,76) in the current closed-loop controller (74); By the parameter of PI controller (64) of regulating the speed, can carry out closed-loop control to the speed of motor;

Dynamic Decoupling Control of Load Torque between displacement and the speed, the rotor field position angle γ according to Hall element (15) detects adopts rotor field-oriented control strategy, through repeatedly coordinate transform realization decoupling zero; To the position control subsystem, the angle γ between two-phase rotation D-Q coordinate system and the static d-q coordinate system of two-phase _B=γ+ _BTo the speed control subsystem, the angle γ between two-phase rotation D-Q coordinate system and the static d-q coordinate system of two-phase _M=γ+ _M, _B, _MIt is respectively the electrical degree between suspending power winding A phase winding axis and motor windings A phase winding axis and the static d axle.

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