阅读说明：本技术 基于九开关逆变器的无轴承电机控制系统 (Bearingless motor control system based on nine-switch inverter ) 是由 仇志坚 卢茂祥 陈王卫 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种基于九开关逆变器的无轴承电机驱动系统,它包括径向悬浮力控制子系统、电磁转矩控制子系统、九开关中管控制子系统与无轴承电机。通过九开关中管控制子系统控制中管信号的生成,九开关上管信号与下管信号分别取自悬浮绕组的上桥臂信号与转矩绕组的下桥臂信号,共生成9路PWM信号输出给九开关逆变器,并控制无轴承永磁同步电机运行。(The invention discloses a bearing-free motor driving system based on a nine-switch inverter, which comprises a radial suspension control subsystem, an electromagnetic torque control subsystem, a tube control subsystem in the nine switches and a bearing-free motor. The generation of the middle tube signal is controlled by the middle tube control subsystem of the nine switches, the upper tube signal and the lower tube signal of the nine switches are respectively taken from the upper bridge arm signal of the suspension winding and the lower bridge arm signal of the torque winding, 9 paths of PWM signals are formed jointly and output to the inverter of the nine switches, and the operation of the bearingless permanent magnet synchronous motor is controlled.)

1. The utility model provides a no bearing motor control system based on nine switch inverters which characterized in that: the system comprises a radial suspension control subsystem (1), an electromagnetic torque control subsystem (2), a nine-switch inverter middle tube control subsystem (3) and a bearingless motor (15), wherein the radial suspension control subsystem (1) and the electromagnetic torque control subsystem (2) are connected with the bearingless motor (15) through the nine-switch inverter middle tube control subsystem (3) to control the bearingless motor (15) to run.

2. The bearingless motor control system based on the nine-switch inverter of claim 1, wherein: the radial suspension force control subsystem (1) comprises displacement regulators (4 and 5), an 2/3 conversion link (6), a current regulator (7) and a suspension SPWM modulation link (8); the displacement regulators (4 and 5) are connected with a suspended SPWM modulation link (8) through an 2/3 conversion link (6) and a current regulator (7) in sequence; the x-direction displacement sensor and the y-direction displacement sensor respectively acquire displacement offsets of an x rotor and a y rotor, reference currents under an a-b-c shaft system are obtained through position negative feedback, an x-direction displacement regulator and a y-direction displacement regulator and through 2/3 transformation, the current sensor acquires three-phase currents of a suspension winding and makes a difference with the reference currents to obtain a difference value e_2A,e_2B,e_2CAnd 6 paths of PWM control signals PWM1, PWM2, PWM3, PWM4, PWM5 and PWM6 of the suspension winding are output through a suspension SPWM modulation link.

3. The bearingless motor control system based on the nine-switch inverter of claim 1, wherein: the electromagnetic torque control subsystem (2) comprises a rotating speed regulator (9), an 2/3 rotation conversion link (10), a current regulator (11) and a torque SPWM modulation link (12); the rotating speed regulator (9) is connected with a torque SPWM modulation link (12) through an 2/3 rotation conversion link (10) and a current regulator (11) in sequence; wherein, the photoelectricityThe encoder detects the position of a rotor to obtain an actual rotating speed, the actual rotating speed is obtained and is subjected to speed negative feedback and 2/3 rotation transformation together with given exciting current to obtain reference current under an a-b-c shafting, the current sensor collects three-phase current of a torque winding and is differed with the reference current to obtain a difference value e_1A,e_1B,e_1cAnd 6 paths of PWM control signals PWM7, PWM8, PWM9, PWM10, PWM11 and PWM12 of the torque winding are output through the torque SPWM modulation link.

4. The bearingless motor control system based on the nine-switch inverter of claim 1, wherein: the middle tube control subsystem (3) of the nine-switch inverter is composed of a middle tube control link (13) and a nine-switch inverter (14); the upper tube signals S1, S2 and S3 of the nine switches are directly obtained from 3 paths of PWM signals of the suspension winding, PWM1, PWM2 and PWM3, and the lower tube signals S6, S7 and S8 of the nine switches are directly obtained from 3 paths of PWM signals PWM10, PWM11 and PWM12 of the torque winding; current difference e of torque winding_1A,e_1B,e_1cCurrent difference e from the levitation winding_2A,e_2B,e_2CAs the input link of the middle pipe control link, when the in-phase current difference e of the torque winding and the suspension winding_1x-e_2xWhen the voltage is greater than 0, the middle tube of the nine-switch inverter is in a conducting state, the corresponding phase tube signal is 1, otherwise, the middle tube of the nine-switch inverter is in a disconnecting state, and the corresponding phase tube signal is 0; e.g. e_1A-e_2AWhen the signal is greater than 0, the pipe signal S4 in the nine-switch is 1, e_1B-e_2BWhen the signal is greater than 0, the pipe signal S5 in the nine-switch is 1, e_1C-e_2CAnd when the signal is greater than 0, the tube signal S6 in the nine-switch is 1.

5. The bearingless motor control system based on the nine-switch inverter of claim 4, wherein: in the nine-switch inverter middle tube control subsystem (3), a nine-switch inverter (14) is composed of 9 discrete IGBTs and has 3 bridge arms in total, wherein each bridge arm is formed by sequentially connecting three IGBTs in series, the nine-switch inverter is provided with two three-phase power output ends, the upper tube of each bridge arm and the midpoint of the middle tube are connected with a torque winding, and the middle tube of each bridge arm of the inverter and the midpoint of the lower tube are connected with a suspension winding.

Technical Field

The invention relates to a bearing-free motor control system based on a nine-switch inverter, which is suitable for the fields of medical treatment, pharmacy, aerospace, high-speed centrifuges and the like.

Background

The bearingless motor is characterized in that a suspension control winding is embedded in a stator of a common motor, the symmetric distribution of an air gap magnetic field is changed through the action of different pole pair suspension winding magnetic fields on an original winding magnetic field, controllable magnetic suspension force is generated on a rotor, the suspension operation of the rotor is realized, the bearingless motor is a technical direction for realizing high rotating speed and high power of an alternating current motor, and the bearingless motor has a wide application prospect.

The inverter circuit of the existing double-winding bearingless motor is composed of two three-phase bridge inverters, and the system is large in size and difficult to integrate, so that a control system of the bearingless motor is complex and high in cost, and popularization and application of the bearingless motor are limited.

Disclosure of Invention

The invention aims to provide a bearing-free motor control system based on a nine-switch inverter. The bearing-free motor control system has the advantages of simplifying the structure of the bearing-free motor control system and reducing the cost.

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

a bearing-free motor control system based on a nine-switch inverter comprises a radial suspension control subsystem, a rotor control subsystem and a motor control subsystem, wherein the radial suspension control subsystem is used for controlling the radial suspension of a rotor; the electromagnetic torque control subsystem is used for controlling electromagnetic torque and regulating the speed of the motor; the nine-switch middle-tube control subsystem is used for outputting control voltage of the double windings, and the sensor is used for measuring the position, radial displacement, winding current and the like of the rotor; the system comprises a radial suspension force control subsystem, an electromagnetic torque control subsystem, a central tube control subsystem of a nine-switch inverter and a bearingless motor, wherein the radial suspension force control subsystem and the electromagnetic torque control subsystem are connected with the bearingless motor through the central tube control subsystem of the nine-switch inverter to control the bearingless motor to run.

Specifically, the radial suspension force control subsystem comprises a displacement regulator, an 2/3 transformation link, a current regulator and an SPWM regulation link; the electromagnetic torque control subsystem comprises a rotating speed regulator, an 2/3 rotation conversion link and a current regulator SPWM modulation link; the sensor comprises a displacement sensor, a photoelectric encoder and a current sensor; the nine-switch inverter control subsystem comprises a current deviation comparison link and a nine-switch inverter.

Furthermore, the nine-switch inverter has 3 bridge arms in total and is composed of 9 discrete switch devices, three IGBTs of each bridge arm are sequentially connected in series, the nine-switch inverter has two three-phase power output ends, the middle tube and the upper tube of each bridge arm are connected with the torque winding, and the middle tube and the lower tube of each bridge arm of the inverter are connected with the suspension winding.

The working principle of the invention is as follows:

radial directionThe suspension control subsystem collects displacement offsets of the rotor in the x and y directions through an x-direction displacement sensor and a y-direction displacement sensor, the displacement offsets are used as input of an x-direction displacement regulator and a y-direction displacement regulator after position negative feedback, reference current of an a-b-c shaft system is obtained through 2/3 transformation, a current sensor collects three-phase stator current of a suspension winding and obtains current deviation e after negative feedback with the reference current_2A,e_2B,e_2CGenerating a reference voltage of an SPWM modulation link through a current regulator, and outputting 6 paths of PWM control numbers of a suspension winding through the SPWM link, namely PWM1, PWM2, PWM3, PWM4, PWM5 and PWM 6; the electromagnetic torque control subsystem detects a rotor position signal by a photoelectric encoder to obtain an actual rotating speed, obtains a torque current after speed loop adjustment, obtains a reference current under an a-b-c shafting through 2/3 rotation transformation together with a given exciting current, acquires a torque winding three-phase current by a current sensor, and performs negative feedback with the reference current to obtain a current deviation e_1A,e_1B,e₁c, generating a reference voltage of an SPWM (sinusoidal pulse width modulation) link through a current regulator, and outputting 6 paths of PWM control numbers of a suspension winding through the SPWM link, namely PWM7, PWM8, PWM9, PWM10, PWM11 and PWM 12; (ii) a Furthermore, the upper tube switch signals S1, S2 and S3 of the nine-switch inverter are directly obtained from the 3 paths of PWM signals PWM1, PWM2 and PWM3 of the suspension winding, the lower tube switch signals S6, S7 and S8 of the nine switches are directly obtained from the 3 paths of PWM signals PWM10, PWM11 and PWM12 of the torque winding, and the current difference e of the torque winding_1A,e_1B,e_1cCurrent difference e from the levitation winding_2A,e_2B,e_2CAs the input link of the middle pipe control link, when the in-phase current difference e of the torque winding and the suspension winding_1x-e_2xWhen the output voltage is greater than 0, the middle tube of the nine-switch inverter is in a conducting state, the corresponding phase tube signal is 1, otherwise, the middle tube of the nine-switch inverter is in a disconnecting state, and the corresponding phase tube signal is 0.

In summary, compared with the traditional control system adopting double inverters to control the bearingless motor, the invention has the following obvious prominent substantive features and remarkable technical progress:

the invention reduces the number of switching devices required in the control process, and is different from the control method which is adopted in the patent CN108173469A and determines the on-off of the upper and lower tubes according to the tracking errors of the upper and lower windings of the bridge arms respectively, and determines the on-off of the middle tube according to the tracking errors of the current of the two motors and the bridge arms.

Drawings

Fig. 1 is a control block diagram of a bearing-less motor system based on a nine-switch inverter according to an embodiment of the present invention, which mainly includes a levitation force control subsystem 1, an electromagnetic torque control subsystem 2, a middle-tube control subsystem 3 of the nine-switch inverter, and an alternating-pole bearing-less permanent magnet synchronous motor 15, wherein the system includes displacement regulators 4 and 5, a rotational speed regulator 9, an 2/3 conversion link 6, a 2/3 rotation conversion link 10, current regulators 7 and 11, a levitation SPWM modulation 8, a torque SPWM12, a middle-tube control link 13, and a nine-switch inverter 14.

Detailed Description

The embodiment of the invention is as follows: a radial suspension force control subsystem, an electromagnetic torque control subsystem and a middle tube control subsystem of a nine-switch inverter are respectively constructed on the basis of a bearing-free motor system control system of the nine-switch inverter.

The following preferred embodiments are described in further detail with reference to the accompanying drawings;