阅读说明：本技术 一种基于双两相三桥臂拓扑的无轴承电机控制系统 (Bearingless motor control system based on double-phase three-bridge-arm topology ) 是由 鲍旭聪 王贝易 于 2021-09-16 设计创作，主要内容包括：本发明公开了一种基于双两相三桥臂拓扑的无轴承电机控制系统,涉及无轴承电机领域,该无轴承电机控制系统中,两个两相三桥臂逆变器分别连接无轴承电机的两相悬浮绕组和无轴承电机的两相转矩绕组,悬浮控制器和转矩控制器基于空间矢量脉宽调制算法控制逆变器的工作状态,该无轴承电机控制系统用两相三桥臂拓扑代替传统的双H桥拓扑,共少了两相桥臂,减少硬件复杂度,且提出了一种基于位移、转速、电流三闭环的无轴承电机空间矢量脉宽调制控制策略,无轴承电机控制系统结构简单、动静态性能好且系统鲁棒性强。(The invention discloses a bearingless motor control system based on a double-phase three-bridge-arm topology, which relates to the field of bearingless motors.)

1. A bearing-free motor control system based on a double-two-phase three-bridge-arm topology is characterized by comprising a bearing-free motor, a first inverter, a second inverter, a suspension controller and a torque controller, wherein the two inverters are two-phase three-bridge-arm inverters;

the torque controller obtains a torque reference current under a dq coordinate system according to a real-time rotor rotation angle of the bearingless motor, obtains a torque actual current under the dq coordinate system according to the real-time torque current of the bearingless motor and the real-time rotor rotation angle, obtains a switching signal of the second inverter according to the torque reference current and the torque actual current and a space vector pulse width modulation algorithm, and acts on the second inverter;

the suspension controller obtains a suspension reference current under a dq coordinate system according to a real-time displacement signal of the bearingless motor and the torque actual current in combination with a preset decoupling model, obtains a suspension actual current under the dq coordinate system according to the real-time suspension current of the bearingless motor in combination with a real-time rotor rotation angle, obtains a switching signal of the first inverter according to the suspension reference current and the suspension actual current in combination with a space vector pulse width modulation algorithm, and acts on the first inverter.

2. The bearingless motor control system of claim 1, wherein the obtaining of the levitation reference current in the dq coordinate system according to the real-time displacement signal of the bearingless motor and the actual torque current in combination with a predetermined decoupling model comprises:

obtaining a rotor radial reference force through a displacement PI regulator according to the real-time displacement signal;

and combining the rotor radial reference force and the actual torque current with a preset decoupling model to obtain a suspension reference current under a dq coordinate system.

3. The bearingless motor control system of claim 2, wherein the obtaining of the levitation reference current in the dq coordinate system according to the rotor radial reference force and the torque actual current in combination with a predetermined decoupling model comprises solving according to the following formula:

wherein i_LdrefIs the d-axis levitation reference current i in dq coordinate system_LqrefIs dq coordinateSuspended reference current, k, tied to the lower q-axis_FAIs a constant coefficient, A_PMIs the magnitude of the magnetic potential of the permanent magnet, W_LIs the total number of turns, W, of the two-phase levitation winding_TIs the total number of turns of the two-phase torque winding, F_xrefAnd F_yrefIs the rotor radial reference force, i_TqIs the torque actual current of the q axis in the dq coordinate system.

4. The bearingless motor control system of claim 1, wherein the obtaining of the levitating actual current in the dq coordinate system according to the real-time levitating current of the bearingless motor in combination with the real-time rotor rotation angle comprises calculating according to the following formula:

wherein i_LdIs the d-axis suspended actual current i in dq coordinate system_LqIs the actual current, theta, of the suspension of the q-axis under the dq coordinate system_rIs the real-time rotor angle i_LaAnd i_LbIs the real-time levitation current of the bearingless motor.

5. The bearingless motor control system of claim 1, wherein the deriving the switching signal of the first inverter from the levitated reference current and the levitated actual current in combination with a space vector pulse width modulation algorithm comprises:

obtaining suspension instruction voltages of a d axis and a q axis under a dq coordinate system by using a current PI regulator according to the suspension reference current and the suspension actual current;

and obtaining a switching signal of the first inverter based on a space vector pulse width modulation algorithm by combining the suspension command voltage and the real-time rotor rotation angle.

6. The bearingless motor control system of claim 1, wherein the deriving a torque reference current in dq coordinate system from a real-time rotor rotation angle of the bearingless motor comprises:

for the real-time rotor rotation angle theta_rCarrying out differential operation to obtain the rotating speed omega of the motor;

obtaining a q-axis torque reference current i under a dq coordinate system through a rotating speed PI regulator_TqrefAnd the torque of the d axis under the dq coordinate system is referenced to the current i_TdrefIs set to 0.

7. The bearingless motor control system of claim 1, wherein the obtaining of the actual torque current in the dq coordinate system from the real-time torque current of the bearingless motor in combination with the real-time rotor rotation angle comprises calculating according to the following formula:

wherein i_TdIs the actual torque current of the d-axis in the dq coordinate system, i_TqIs the actual torque current of the q-axis in the dq coordinate system, theta_rIs the real-time rotor angle i_TaAnd i_TbIs the real-time torque current of the bearingless motor.

8. The bearingless motor control system of claim 1, wherein the deriving and acting on the second inverter switching signals from a torque reference current and a torque actual current in combination with a space vector pulse width modulation algorithm comprises:

obtaining torque command voltages of a d axis and a q axis under a dq coordinate system by using a current PI regulator according to the torque reference current and the torque actual current;

and combining the torque command voltage and the real-time rotor rotation angle to obtain a switching signal of the second inverter based on a space vector pulse width modulation algorithm.

9. A bearingless motor control system according to any one of claims 1 to 8,

the real-time torque current and the real-time suspension current are obtained by sampling through a Hall current sensor, the real-time rotor rotation angle is obtained by calculating an angle value sampled by the Hall sensor, and the real-time displacement signal is obtained by sampling through an eddy current sensor.

Technical Field

The invention relates to the field of bearingless motors, in particular to a bearingless motor control system based on a double-phase three-bridge-arm topology.

Background

The bearingless motor adopts a magnetic suspension technology to suspend the motor rotor, thereby avoiding the problems of short service life of a bearing, high maintenance cost, high mechanical noise and the like caused by mechanical loss of the traditional mechanical bearing motor, and having the advantages of small volume, easy installation, high precision and the like.

The traditional double-H bridge inverter topology is mostly adopted for the two-phase bearingless motor at present, and for the bearingless motor with two sets of windings of suspension and torque, 4H bridges are needed totally, the hardware structure of the system is complex, and the cost is high.

Disclosure of Invention

The invention provides a bearing-free motor control system based on a double-two-phase three-bridge arm topology aiming at the problems and the technical requirements, and the technical scheme of the invention is as follows:

a bearing-free motor control system based on a double-phase three-bridge-arm topology comprises a bearing-free motor, a first inverter, a second inverter, a suspension controller and a torque controller, wherein the two inverters are two-phase three-bridge-arm inverters;

the torque controller obtains a torque reference current under a dq coordinate system according to a real-time rotor rotation angle of the bearingless motor, obtains a torque actual current under the dq coordinate system according to the real-time torque current of the bearingless motor and the real-time rotor rotation angle, obtains a switching signal of the second inverter according to the torque reference current and the torque actual current and a space vector pulse width modulation algorithm, and acts on the second inverter;

the suspension controller combines a preset decoupling model to obtain a suspension reference current under a dq coordinate system according to a real-time displacement signal and a torque actual current of the bearingless motor, combines a real-time rotor rotation angle to obtain a suspension actual current under the dq coordinate system according to the real-time suspension current of the bearingless motor, and combines a space vector pulse width modulation algorithm to obtain a switching signal of the first inverter according to the suspension reference current and the suspension actual current and acts on the first inverter.

The further technical scheme is that the method for obtaining the suspension reference current under the dq coordinate system according to the combination of the real-time displacement signal and the actual torque current of the bearingless motor and a preset decoupling model comprises the following steps:

obtaining a rotor radial reference force through a displacement PI regulator according to the real-time displacement signal;

and combining the rotor radial reference force and the torque actual current with a preset decoupling model to obtain the suspension reference current under the dq coordinate system.

The further technical scheme is that the method obtains the suspension reference current under the dq coordinate system by combining a preset decoupling model according to the rotor radial reference force and the torque actual current, and comprises the following steps of:

wherein i_LdrefIs the d-axis levitation reference current i in dq coordinate system_LqrefIs the levitation reference current, k, of the q-axis in the dq coordinate system_FAIs a constant coefficient, A_PMIs the magnitude of the magnetic potential of the permanent magnet, W_LIs the total number of turns, W, of the two-phase levitation winding_TIs the total number of turns of the two-phase torque winding, F_xrefAnd F_yrefIs the rotor radial reference force, i_TqIs the torque actual current of the q axis in the dq coordinate system.

The further technical scheme is that the suspension actual current under the dq coordinate system is obtained according to the combination of the real-time suspension current of the bearingless motor and the real-time rotor rotation angle, and the method comprises the following steps of:

wherein i_LdIs the d-axis suspended actual current i in dq coordinate system_LqIs the actual current, theta, of the suspension of the q-axis under the dq coordinate system_rIs the real-time rotor angle i_LaAnd i_LbIs the real-time suspension current of the bearingless motor.

The further technical scheme is that the method for obtaining the switching signal of the first inverter according to the combination of the suspension reference current and the suspension actual current and the space vector pulse width modulation algorithm comprises the following steps:

obtaining suspension instruction voltages of a d axis and a q axis under a dq coordinate system by using a current PI regulator according to the suspension reference current and the suspension actual current;

and obtaining a switching signal of the first inverter based on a space vector pulse width modulation algorithm by combining the suspension command voltage and the real-time rotor rotation angle.

The further technical scheme is that the method for obtaining the torque reference current under the dq coordinate system according to the real-time rotor rotation angle of the bearingless motor comprises the following steps:

for real-time rotor rotation angle theta_rCarrying out differential operation to obtain the rotating speed omega of the motor;

obtaining a q-axis torque reference current i under a dq coordinate system through a rotating speed PI regulator_TqrefAnd the torque of the d axis under the dq coordinate system is referenced to the current i_TdrefIs set to 0.

The further technical scheme is that the actual torque current under the dq coordinate system is obtained according to the combination of the real-time torque current of the bearingless motor and the real-time rotor rotation angle, and the method comprises the following steps of:

wherein i_TdIs the actual torque current of the d-axis in the dq coordinate system, i_TqIs the actual torque current of the q-axis in the dq coordinate system, theta_rIs the real-time rotor angle i_TaAnd i_TbIs the real-time torque current of the bearingless motor.

The further technical scheme is that a switching signal of the second inverter is obtained according to the combination of the torque reference current and the torque actual current and a space vector pulse width modulation algorithm and acts on the second inverter, and the method comprises the following steps:

obtaining torque command voltages of a d axis and a q axis under a dq coordinate system by using a current PI regulator according to the torque reference current and the torque actual current;

and obtaining a switching signal of the second inverter based on a space vector pulse width modulation algorithm by combining the torque command voltage and the real-time rotor rotation angle.

The further technical scheme is that the real-time torque current and the real-time suspension current are obtained by sampling through a Hall current sensor, the real-time rotor rotation angle is obtained by calculating an angle value sampled by the Hall sensor, and the real-time displacement signal is obtained by sampling through an eddy current sensor.

The beneficial technical effects of the invention are as follows:

the application discloses no bearing motor control system based on two-phase three-bridge arm topology, should replace traditional two H bridge topology with two-phase three-bridge arm topology, combine space vector pulse width modulation algorithm, a no bearing motor space vector pulse width modulation control strategy based on displacement, rotational speed, three closed loops of electric current has been proposed, can realize the stable suspension and the rotation of no bearing motor, two-phase bridge arm has been lacked altogether in two H bridge topology, reduce the hardware complexity, and no bearing motor control system under this kind of control strategy simple structure, the dynamic and static performance is good and the system robustness is strong.

Drawings

FIG. 1 is a schematic control logic diagram of the bearingless motor control system of the present application.

Fig. 2 is a circuit diagram of a two-phase three-leg inverter in the present application.

Detailed Description

The following further describes the embodiments of the present invention with reference to the drawings.

The application discloses a bearingless motor control system based on a double two-phase three-bridge arm topology, please refer to fig. 1, the bearingless motor control system comprises a bearingless motor, a first inverter, a second inverter, a levitation controller and a torque controller, and also comprises some sampling components such as sensors, which are not shown in detail in fig. 1.

The direct current power supply is connected with the two-phase suspension winding of the bearingless motor through a first inverter, and the direct current power supply is connected with the two-phase torque winding of the bearingless motor through a second inverter. Both inverters are two-phase three-bridge arm inverters, please refer to fig. 2, switch tube T₁And T₂Form a first bridge arm and a switch tube T₃And T₄Form a second bridge arm and a switch tube T₅And T₆A third bridge arm is formed, and the three bridge arms are connected in parallel and are respectively connected to a direct current power supply U_dcPositive and negative electrodes of (1). The leading-out terminals of the A phases of the two-phase suspension windings are respectively connected with the middle point of the first bridge arm and the middle point of the second bridge arm in the first inverter, and the leading-out terminals of the B phases of the two-phase suspension windings are respectively connected with the middle point of the first bridge arm and the middle point of the second bridge arm. The leading-out terminals of the A phases of the two-phase torque windings are respectively connected with the middle point of the first bridge arm and the middle point of the second bridge arm of the second inverter, and the leading-out terminals of the B phases of the two-phase torque windings are respectively connected with the middle point of the first bridge arm and the middle point of the second bridge arm.

The suspension controller is connected with and controls the working state of the first inverter, and the torque controller is connected with and controls the working state of the second inverter, specifically the state of each switching tube in the inverters. In addition, the suspension controller and the torque controller also acquire various working parameters of the bearingless motor through various sampling assemblies.

In the working process of the bearingless motor control system, various working parameters of the bearingless motor to be collected comprise: (1) real-time levitation current i_LaAnd i_Lb(ii) a (2) Real time torque current i_TaAnd i_Tb(ii) a (3) Real-time rotor angle theta_r(ii) a (4) Real-time displacement signal D_xy. Wherein, the real-time suspension current i_LaAnd i_LbThe sampling is respectively obtained through Hall current sensors arranged on the A phase and the B phase of the two-phase suspension winding. Real time torque current i_TaAnd i_TbThe sampling is respectively obtained through Hall current sensors arranged on the A phase and the B phase of the two-phase torque winding. Real-time rotor angle theta_rThe method for calculating the real-time rotor rotation angle is obtained by calculating the angle value sampled by the Hall sensor, is a conventional method, and is not developed in the application. Real-time displacement signal D_xyObtained by sampling through an eddy current sensor.

Referring to the schematic control logic diagram of the torque controller and the torque controller shown in fig. 1, the control methods of the two controllers are as follows:

the control process of the torque controller comprises the following steps:

1. the torque controller is based on the real-time rotor rotation angle theta of the bearingless motor_rObtaining a torque reference current i under a dq coordinate system_TdrefAnd i_Tqref。

Specifically, for real-time rotor rotation angle θ_rCarrying out differential operation to obtain the motor rotation speed omega, and combining the motor reference rotation speed omega_refObtaining a q-axis torque reference current i under a dq coordinate system through a rotating speed PI regulator_TqrefThe torque of the d axis under the dq coordinate system is referenced to the current i_TdrefIs set to 0.

2. According to the real-time torque current i of the bearingless motor_Ta、i_TbIncorporating real-time rotor angle θ_rObtaining the actual torque current i of the d axis under the dq coordinate system_TdAnd the torque actual current i of the q axis_Tq. The actual processing is performed by means of coordinate transformation, including calculation according to the following formula:

3. according to the torque reference current i_Tdref、i_TqrefAnd actual torque current i_Td、i_TqAnd combining a space vector pulse width modulation algorithm to obtain a switching signal of the second inverter and applying the switching signal to the second inverter.

Specifically, firstly, the torque command voltages of a d axis and a q axis in a dq coordinate system are obtained by using a current PI regulator according to a torque reference current and a torque actual current: using the d-axis torque reference current i in the dq coordinate system_TdrefAnd the actual torque current i_TdPerforming current PI regulation to obtain a d-axis torque command voltage u_TdUsing the torque reference current i of q-axis under dq coordinate system_TqrefAnd the actual torque current i_TqCarrying out current PI regulation to obtain a torque command voltage u of a q axis_Tq. Space vector pulse width modulation algorithm based on two-phase three-bridge arm and combined with torque command voltage u_Td、u_TqAnd real time rotor angle θ_rAnd obtaining a switching signal of the second inverter.

Secondly, the control process of the suspension controller comprises the following steps:

1. the suspension controller is based on the real-time displacement signal D of the bearingless motor_xyCombining the actual torque current with a preset decoupling model to obtain a suspension reference current i under a dq coordinate system_LdrefAnd i_Lqref。

Specifically, first, according to the real-time displacement signal D_xyCombined with a displacement reference signal D set to 0_xyrefObtaining a rotor radial reference force F by a displacement PI regulator_xrefAnd F_yref. Then according to the rotor radial reference force F_xref、F_yrefCombining the actual torque current with a preset decoupling model to obtain a d-axis suspension reference current i under a dq coordinate system_LdrefAnd q-axis levitated reference current i_LqrefThe torque actual current is calculated as described above, and in this step, the torque actual current i of the q axis in the dq coordinate system is mainly used_Tq. Comprises the following steps:

wherein k is_FAIs a constant coefficient and is related to a bearingless motor structure. A. the_PMIs the magnitude of the magnetic potential of the permanent magnet, W_LIs the total number of turns, W, of the two-phase levitation winding_TIs the total number of turns of the two-phase torque winding.

2. According to the real-time suspension current i of the bearingless motor_La、i_LbIncorporating real-time rotor angle θ_rObtaining the suspension actual current i of the d axis under the dq coordinate system_LdAnd q-axis levitating actual current i_Lq. The actual processing is performed by means of coordinate transformation, including calculation according to the following formula:

3. and obtaining a switching signal of the first inverter according to the combination of the suspension reference current and the suspension actual current and a space vector pulse width modulation algorithm, and acting the switching signal on the first inverter.

Specifically, firstly, the floating reference current i is used_Ldref、i_LqrefAnd a floating actual current i_Ld、i_LqObtaining torque command voltages of a d axis and a q axis under a dq coordinate system by using a current PI regulator: using d-axis suspension reference current i under dq coordinate system_LdrefAnd a floating actual current i_LdCarrying out current PI regulation to obtain d-axis suspension command voltage u_Ld(ii) a Using q-axis floating reference current i under dq coordinate system_LqrefAnd a floating actual current i_LqCarrying out current PI regulation to obtain q-axis suspension command voltage u_Lq. Space vector pulse width modulation algorithm based on two-phase three-bridge arm and combined with torque command voltage u_Ld、u_LqAnd real time rotor angle θ_rA switching signal of the first inverter is obtained.

What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiment. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and concept of the present invention are to be considered as included within the scope of the present invention.