阅读说明：本技术 一种降低长定子同步直线电机定子供电电压的装置及方法 (Device and method for reducing power supply voltage of stator of long-stator synchronous linear motor ) 是由 吴杰 王滢 高黎明 余帆 张昆仑 刘世杰 刘方麟 陈绍宗 于 2021-08-26 设计创作，主要内容包括：本发明提供了一种降低长定子同步直线电机定子供电电压的装置及方法,本发明在电机定子侧输入端添加动态吸收电路,该动态吸收电路由电容和控制开关组成；速度发生变化时,控制并联支路上控制开关的开断调节动态吸收电路总电容值,使得动态吸收电路的总电抗值约等于长定子直线同步电机的电枢绕组外部主漏抗,动态吸收电路中电容产生容性压降补偿电枢绕组外部主漏抗产生的感性压降,电枢绕组输入回路的总漏抗降低,在输入相同电流情况下,本发明能够使长定子同步直线电机的定子供电电压明显下降,从而可大大增加定子供电区段的长度。同理,在恒定电压工作状态时,电机电枢绕组能够获得更大的电流,从而获得更大的牵引力,提高系统效率。(The invention provides a device and a method for reducing the stator supply voltage of a long-stator synchronous linear motor, wherein a dynamic absorption circuit is added at the input end of the stator side of the motor and consists of a capacitor and a control switch; when the speed changes, the on-off of the control switch on the parallel branch is controlled to adjust the total capacitance value of the dynamic absorption circuit, so that the total reactance value of the dynamic absorption circuit is approximately equal to the main leakage reactance outside the armature winding of the long-stator linear synchronous motor, the capacitance in the dynamic absorption circuit generates capacitive voltage drop to compensate the inductive voltage drop generated by the main leakage reactance outside the armature winding, the total leakage reactance of the armature winding input loop is reduced, and under the condition of inputting the same current, the stator power supply voltage of the long-stator linear synchronous motor can be obviously reduced, so that the length of a stator power supply section can be greatly increased. Similarly, when the motor works at a constant voltage, the armature winding of the motor can obtain larger current, so that larger traction force is obtained, and the system efficiency is improved.)

1. A device for reducing the power supply voltage of a stator of a long-stator synchronous linear motor is characterized by comprising an armature winding of the long-stator synchronous linear motor and a dynamic absorption circuit arranged at the input end of the armature winding of the long-stator synchronous linear motor;

the dynamic absorption circuit comprises a plurality of parallel-connected series branches, each series branch comprises a capacitor and a control switch, the plurality of parallel-connected series branches are connected with the input end of the armature winding of the long-stator synchronous linear motor, and the total reactance of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

2. A method for reducing the stator supply voltage of a long stator synchronous linear motor is characterized by comprising the following steps:

s1, arranging a dynamic absorption circuit at the input end of the armature winding of the long stator synchronous linear motor;

s2, making the total reactance value of the dynamic absorption circuit approximately equal to the external main leakage reactance of the armature winding of the long stator synchronous linear motor;

and S3, based on the fact that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor, the power supply voltage of the long-stator synchronous linear motor is reduced.

3. The method according to claim 2, wherein the dynamic absorption circuit in step S1 includes a plurality of parallel series-connected branches, each of the series-connected branches includes a capacitor and a control switch, and the plurality of parallel series-connected branches are connected to the input end of the long-stator synchronous linear motor armature winding.

4. The method for reducing the stator supply voltage of the long-stator synchronous linear motor according to claim 3, wherein the step S2 is specifically as follows: when the speed of the long-stator synchronous linear motor changes, the on-off of the control switch on the parallel branch is controlled to adjust the equivalent capacitance value of the dynamic absorption circuit, so that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

5. The method for reducing the stator supply voltage of the long-stator synchronous linear motor according to claim 4, wherein when the speed of the long-stator synchronous linear motor changes, the on/off of the control switch on the parallel branch is controlled to adjust the equivalent capacitance value of the dynamic absorption circuit, which is specifically as follows:

when the speed of the long-stator synchronous linear motor rises, the control switches on the parallel branches are sequentially disconnected through the dynamic absorption circuit, so that the total capacitance value of the dynamic absorption circuit is reduced, and the total capacitive reactance value of the dynamic absorption circuit is increased, and the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor;

when the speed of the long-stator synchronous linear motor is reduced, the dynamic absorption circuit sequentially closes the control switches on the parallel branch circuits, so that the total capacitance value of the dynamic absorption circuit is increased, and the capacitive reactance value of the dynamic absorption circuit is reduced, so that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

Technical Field

The invention belongs to the technical field of long-stator linear synchronous motors, and particularly relates to a device and a method for reducing power supply voltage of a stator of a long-stator linear synchronous motor.

Background

The long stator linear synchronous motor is applied in many occasions due to the special mechanism and performance characteristics of the long stator linear synchronous motor, and a good effect is achieved. When the long stator linear synchronous motor is applied to the transportation industry, the long stator linear synchronous motor is mainly used as a driving motor of a high-speed magnetic suspension train. The magnetic suspension train changes the traditional rail vehicle propelling mode by the friction force of wheel tracks, adopts a magnetic suspension train body, uses a long stator linear synchronous motor as a core driving unit of the magnetic suspension technology, and bears the important function of train driving.

In the stator section electrifying area of the long stator linear synchronous motor, the secondary stage only occupies a small part of the stator section, and the inter-pole reactance of the stator area without the magnetic pole coverage is called as external main leakage reactance. Because the motor stator is longer, the external main leakage inductance cannot be ignored, and when the maglev train runs at a higher speed, the external main leakage reactance of the stator is increased along with the speed rise. Due to the existence of the external main leakage reactance, the voltage of the end part of the stator winding is partially used for overcoming the leakage reactance voltage drop of the stator winding, the voltage of the motor end is increased due to the leakage reactance voltage drop, the power supply area of the stator section is short, the electric energy loss is caused, and the motor efficiency is reduced.

Disclosure of Invention

Aiming at the defects in the prior art, the device and the method for reducing the stator power supply voltage of the long-stator synchronous linear motor provided by the invention greatly increase the power supply area of the stator section and improve the motor efficiency.

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

the scheme provides a device for reducing the power supply voltage of a stator of a long-stator synchronous linear motor, which comprises an armature winding of the long-stator synchronous linear motor and a dynamic absorption circuit arranged at the input end of the armature winding of the long-stator synchronous linear motor;

the dynamic absorption circuit comprises a plurality of parallel-connected series branches, each series branch comprises a capacitor and a control switch, the plurality of parallel-connected series branches are connected with the input end of the armature winding of the long-stator synchronous linear motor, and the total reactance of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

The invention also provides a method for reducing the power supply voltage of the stator of the long-stator synchronous linear motor, which comprises the following steps:

s1, arranging a dynamic absorption circuit at the input end of the armature winding of the long stator synchronous linear motor;

s2, making the total reactance value of the dynamic absorption circuit approximately equal to the external main leakage reactance of the armature winding of the long stator synchronous linear motor;

and S3, based on the fact that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor, the power supply voltage of the long-stator synchronous linear motor is reduced.

Further, the dynamic absorption circuit in step S1 includes a plurality of parallel series branches, each of the series branches includes a capacitor and a control switch, and the plurality of parallel series branches are connected to the input end of the long stator synchronous linear motor armature winding.

Still further, step S2 is specifically: when the speed of the long-stator synchronous linear motor changes, the on-off of the control switch on the parallel branch is controlled to adjust the equivalent capacitance value of the dynamic absorption circuit, so that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

Still further, when the speed of the long-stator synchronous linear motor changes, the on-off of the control switch on the parallel branch is controlled to adjust the equivalent capacitance value of the dynamic absorption circuit, which specifically comprises:

when the speed of the long-stator synchronous linear motor rises, the control switches on the parallel branches are sequentially disconnected through the dynamic absorption circuit, so that the total capacitance value of the dynamic absorption circuit is reduced, and the total capacitive reactance value of the dynamic absorption circuit is increased, and the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor;

when the speed of the long-stator synchronous linear motor is reduced, the dynamic absorption circuit sequentially closes the control switches on the parallel branch circuits, so that the total capacitance value of the dynamic absorption circuit is increased, and the capacitive reactance value of the dynamic absorption circuit is reduced, so that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

The invention has the beneficial effects that:

the dynamic absorption circuit is added at the input end of the motor stator side, and comprises a capacitor and a control switch; when the speed changes, the on-off of the control switch on the parallel branch is controlled to adjust the total capacitance value of the dynamic absorption circuit, so that the total reactance value of the dynamic absorption circuit is approximately equal to the main leakage reactance outside the armature winding of the long-stator linear synchronous motor, the capacitance in the dynamic absorption circuit generates capacitive voltage drop to compensate the inductive voltage drop generated by the main leakage reactance outside the armature winding, the total leakage reactance of the armature winding input loop is reduced, and under the condition of inputting the same current, the stator power supply voltage of the long-stator linear synchronous motor can be obviously reduced, so that the length of a stator power supply section can be greatly increased. Similarly, when the long-stator synchronous linear motor is in a constant-voltage working state, the armature winding of the motor can obtain larger current, so that larger traction force is obtained, and the system efficiency is improved.

Drawings

FIG. 1 is a schematic structural diagram of the apparatus of the present invention.

Fig. 2 is a schematic view of the method for reducing the stator supply voltage of the long stator synchronous linear motor according to the present invention.

Fig. 3 is a schematic diagram of a dynamic absorption circuit for reducing the stator supply voltage of the long stator synchronous linear motor according to the method of the present invention.

Fig. 4 is an equivalent circuit diagram of a single-phase stator winding when the method for reducing the stator supply voltage of the long-stator synchronous linear motor is used in the embodiment of the invention.

Fig. 5 is a schematic diagram of a dynamic absorption circuit for reducing the supply voltage of the stator of the long-stator synchronous linear motor according to the present invention.

FIG. 6 is a comparison graph of the stator supply voltage of the motor using the power supply and direct power supply method of the present invention at speeds of 350km/h, 400km/h and 450km/h in this example.

FIG. 7 is a flow chart of the method of the present invention.

The synchronous linear motor comprises a stator, a first dynamic absorption circuit, a second dynamic absorption circuit, a third dynamic absorption circuit, a long stator synchronous linear motor, a first capacitor, a first control switch, a second capacitor and a second control switch, wherein the first dynamic absorption circuit is 1, the second dynamic absorption circuit is 2, the third dynamic absorption circuit is 3, the long stator synchronous linear motor is 4, the first capacitor is 5, the first control switch is 6, the second control switch is 7, and the second control switch is 8.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

Example 1

Aiming at the problem of the increase of the power supply voltage of the stator of the long-stator linear synchronous motor caused by the external main leakage reactance of the long-stator linear synchronous motor under the condition of high-speed operation of the long-stator linear synchronous motor, the invention aims to provide a method for adjusting a capacitance value by using a dynamic absorption circuit to compensate the leakage inductance of the stator of the long-stator linear synchronous motor, thereby reducing the power supply voltage of the stator of the long-stator linear synchronous motor.

As shown in fig. 1, the present invention provides a device for reducing the stator supply voltage of a long stator synchronous linear motor, which comprises a long stator synchronous linear motor armature winding and a dynamic absorption circuit arranged at the input end of the long stator synchronous linear motor armature winding; the dynamic absorption circuit comprises a plurality of parallel-connected series branches, each series branch comprises a capacitor and a control switch, the plurality of parallel-connected series branches are connected with the armature winding of the long-stator synchronous linear motor, and the total reactance of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor.

In this embodiment, as shown in fig. 2, a first dynamic absorber circuit 1, a second dynamic absorber circuit 2, and a third dynamic absorber circuit 3 are added in parallel to an input end of a stator 4 of a long-stator synchronous linear motor. As shown in fig. 3, the dynamic compensation circuit includes a first capacitor 5, a second capacitor 7, a first control switch 8 and a second control switch 8, and as can be seen from the parallel capacitance characteristic, when the first control switch 6 is open, the total capacitance of the dynamic compensation circuit is reduced and the total reactance is increased compared with when the first control switch 6 and the second control switch 8 are both closed.

In this embodiment, as shown in fig. 4, the equivalent circuit of the one-phase stator winding of the long-stator synchronous linear motor includes an input voltageInput currentArmature winding equivalent resistance R, armature winding main reactance X_mMain leakage reactance X of armature winding_σAnd armature reaction electromotive forceThe first dynamic absorption circuit 1 of the present invention is connected in series therein. Total reactance value of dynamic absorption circuit of the inventionArmature winding external main leakage reactance X approximately equal to long stator linear synchronous motor_σ＝ωL_σI.e. byWhere ω represents the input voltageThe angular frequency of (c). When the motor speed rises, the frequency of the stator current increases, omega increases, and the main leakage reactance X outside the armature winding increases_σTo increase the above relationship, the equivalent capacitance of the dynamic absorption circuit needs to be reduced, that is, the parallel branch of the dynamic absorption circuit is reduced by controlling the switch, when the speed of the motor decreases, the frequency of the stator current decreases, ω decreases, and the main leakage reactance X outside the armature winding decreases_σDecrease; in order to ensure the above relationship, it is necessary to increase the equivalent capacitance of the dynamic absorption circuit, i.e. the number of parallel branches of the absorption circuit is increased by controlling the switch.

The existing long stator synchronous linear motor for high-speed maglev train has armature winding length of 1.2km, armature pole distance of 258mm, motor phase number of 3, slot number of each phase of each pole of 1, and stator current of 1200A; the rotor comprises 1 magnetic pole module, which is composed of 12 main magnetic poles and 2 half magnetic poles. The pole pitch of the excitation magnetic pole is 266.5mm, the number of turns of the excitation winding is 270, the length of a main pole air gap is 10mm, the current is 20A, the stator side directly supplies power by using constant current, and the running speeds are 350km/h, 400km/h and 450km/h respectively. The long stator linear synchronous motor uses the device of the invention, a dynamic absorption circuit of the motor with the speed of 0-450km/h is designed according to the motor parameters in the example, and the main leakage inductance of the stator is 1.2mH according to calculation. Total reactance value of dynamic absorption circuit of the inventionArmature winding external main leakage reactance X approximately equal to long stator linear synchronous motor_σ＝ωL_σWhereinv represents the train running speed, and tau represents the motor pole pitch. Therefore, the equivalent capacitance values of the dynamic absorption circuit at different speeds can be obtained. The capacitance values of the parallel branches are determined according to equivalent capacitance values at different speeds, because the end voltage of the motor is lower when the speed of the motor is less than 200km/h, a capacitor with a larger capacitance value is used to be connected in series into the dynamic absorption circuit, and after the speed is more than 200km/h, the speed is 50km/h as a grade, and the structure of the dynamic absorption circuit of the embodiment is shown in fig. 5. When the running speed is less than 200km/h, all switches of the dynamic absorption circuit are closed, the branch control switches are sequentially disconnected along with the rise of the speed, when the speed of the motor is 400km/h, the equivalent capacitance value of the absorption circuit is 450uf, and the switches K6 and K7 are closed by the dynamic absorption circuit; when the motor speed is 450km/h, the equivalent capacitance value of the absorption circuit is 350uf, the dynamic absorption circuit controls the switch K6 to be opened, and only K7 is closed.

In this embodiment, when the selected motor speeds are 350km/h, 400km/h and 450km/h, respectively, a comparison graph of the power supply voltage of the device for reducing the power supply voltage of the stator of the long-stator synchronous linear motor and the power supply voltage of the direct power supply method of the present invention is shown in fig. 6, and it can be known from fig. 6 that, under the three speeds, the voltage reduction of the device for reducing the power supply voltage of the stator of the long-stator synchronous linear motor of the present invention is about 50% compared with the voltage reduction of the direct power supply method. Compared with a direct power supply method, the device for reducing the power supply voltage of the stator of the long-stator synchronous linear motor can effectively reduce the power supply voltage of the stator when the armature winding input current is the same, and can compensate the reactance of the armature winding of the long-stator synchronous motor by increasing the reactance of the absorption circuit through the branch capacitor of the dynamic absorption circuit in the process of increasing the speed, thereby improving the efficiency of a power supply system. Similarly, when the power supply voltage is equal by using the device for reducing the power supply voltage of the stator of the long-stator synchronous linear motor and the direct power supply method, the stator winding of the motor can obtain larger current so as to obtain larger traction force. Therefore, the invention can effectively improve the efficiency of the linear synchronous motor and increase the power supply distance of the stator section.

Example 2

As shown in fig. 7, the present invention provides a method for reducing the stator supply voltage of a long stator synchronous linear motor, which is implemented as follows:

s1, arranging a dynamic absorption circuit at the input end of the armature winding of the long stator synchronous linear motor;

the dynamic absorption circuit comprises a plurality of parallel-connected serial branches, each serial branch comprises a capacitor and a control switch, and the plurality of parallel-connected serial branches are connected with the stator of the long-stator synchronous linear motor;

s2, making the total reactance value of the dynamic absorption circuit approximately equal to the external main leakage reactance of the armature winding of the long stator synchronous linear motor, specifically the external main leakage reactance value; when the speed of the long-stator synchronous linear motor changes, the on-off of the control switch on the parallel branch is controlled to adjust the equivalent capacitance value of the dynamic absorption circuit, so that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor, namely: when the speed of the long-stator synchronous linear motor rises, the control switches on the parallel branches are sequentially disconnected through the dynamic absorption circuit, so that the total capacitance value of the dynamic absorption circuit is reduced, and the total capacitive reactance value of the dynamic absorption circuit is increased, and the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor; when the speed of the long-stator synchronous linear motor is reduced, the dynamic absorption circuit sequentially closes the control switches on the parallel branch circuits, so that the total capacitance value of the dynamic absorption circuit is increased, and the capacitive reactance value of the dynamic absorption circuit is reduced, so that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor;

and S3, based on the fact that the total reactance value of the dynamic absorption circuit is approximately equal to the external main leakage reactance of the armature winding of the long-stator synchronous linear motor, the power supply voltage of the long-stator synchronous linear motor is reduced.

The dynamic absorption circuit is added at the input end of the motor stator side, and consists of a capacitor and a control switch; when the speed changes, the on-off of the control switch on the parallel branch is controlled to adjust the total capacitance value of the dynamic absorption circuit, so that the total reactance value of the dynamic absorption circuit is approximately equal to the main leakage reactance outside the armature winding of the long-stator linear synchronous motor, the capacitance in the dynamic absorption circuit generates capacitive voltage drop to compensate the inductive voltage drop generated by the main leakage reactance outside the armature winding, the total leakage reactance of the armature winding input loop is reduced, and under the condition of inputting the same current, the stator power supply voltage of the long-stator linear synchronous motor can be obviously reduced, so that the length of a stator power supply section can be greatly increased. Similarly, when the long-stator synchronous linear motor is in a constant-voltage working state, the armature winding of the motor can obtain larger current, so that larger traction force is obtained, and the system efficiency is improved.