A permanent magnet motor with an axial translational magnetic ring for reactive power compensation

Abstract

This invention discloses an axially translating permanent magnet motor for reactive power compensation, mainly comprising a permanent magnet rotor, an adjusting ring, and a stator. The adjusting ring is a circular ring structure, stationary, and its axial relative position with the permanent magnet rotor can be arbitrarily adjusted. The axial relative position between the permanent magnet rotor and the armature stator remains unchanged, and the output shaft of the permanent magnet rotor is unloaded. Since the output shaft is unloaded, and motor losses and rotor mechanical transients are not considered, the motor's input active power is always zero. The three-phase armature windings are connected to the power grid. The axial relative position between the adjusting ring and the permanent magnet rotor is adjusted mechanically, short-circuiting the magnetomotive force of the magnets through the adjusting ring. Because there is no complex excitation system for adjusting the motor's excitation current, and because the adjusting ring is a non-rotating component, it is easy to adjust online. Therefore, it has the advantages of simple structure, low cost, high efficiency, and high reliability, making it very suitable as a reactive power compensation motor for power systems.

Description

Technical Field

[0001] This invention belongs to the field of special motor device technology, specifically relating to a permanent magnet motor with an axial translational magnetic ring for reactive power compensation. Background Technology

[0002] As a dedicated reactive power source, the phase-shifting motor, compared with other reactive power sources (parallel capacitors, reactors, SVCs, STATCOMs, etc.), has less influence on reactive power output from system voltage, possesses instantaneous reactive power support, and strong short-term overload capability; its output reactive power can be continuously controlled with high precision, easily improving system stability; and it has advantages such as fast tracking speed (able to suppress flicker or impulses), wide compensation range (capacitive and inductive), and low failure rate. Currently, the phase-shifting motors used for reactive power compensation in power systems are generally electrically excited synchronous phase-shifting motors. The main disadvantages of electrically excited synchronous phase-shifting motors are: 1) More complex structure: due to the presence of an electric excitation coil on the rotor side, the excitation coil requires a complex excitation system for power supply, leading to reduced system reliability; 2) Lower efficiency: due to the presence of an excitation coil in the electrically excited synchronous condenser, excitation consumes some power, reducing system operating efficiency.

[0003] To overcome the above difficulties, this invention proposes an axial translational permanent magnet motor with a magnetic ring for reactive power compensation. It has the advantages of simple structure, high power density, high efficiency and high reliability, and is very suitable for reactive power compensation in power systems. Summary of the Invention

[0004] To address the aforementioned problems and overcome the shortcomings of existing technologies, this invention provides an axial translational permanent magnet motor with a magnetic ring for reactive power compensation. The motor comprises a permanent magnet rotor, a magnetic ring, and an armature stator, and features a simple structure, high power density, high efficiency, and high reliability.

[0005] Technical Solution: This invention proposes an axially translating permanent magnet motor for reactive power compensation, mainly comprising a permanent magnet rotor, an adjusting ring, and a stator. The adjusting ring is a circular ring structure and is stationary. The axial relative position between the adjusting ring and the permanent magnet rotor can be arbitrarily adjusted. The axial relative position between the permanent magnet rotor and the armature stator remains unchanged, and the output shaft of the permanent magnet rotor is unloaded. By adjusting the axial relative position between the adjusting ring and the permanent magnet rotor, the active power of the motor can be made zero, while the reactive power can be arbitrarily adjusted. Compared with conventional electrically excited synchronous phase-shifting motors, this motor has the advantages of simple structure, high power density, high efficiency, and high reliability, making it very suitable for reactive power compensation in power systems.

[0006] As a preferred option, the motor stator adopts an internal stator design, which allows for convenient online adjustment of the axial relative position of the adjusting magnetic ring via a control mechanism.

[0007] Beneficial effects: The axial translational permanent magnet motor with adjusting magnetic ring for reactive power compensation of the present invention has the advantages of simple structure, high power density, high efficiency and high reliability. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the motor topology of the present invention;

[0009] Figure 2 To adjust the distribution of magnetic lines of force (maximum magnetic flux) of the motor when the magnetic ring and the permanent magnet rotor are completely misaligned axially.

[0010] Figure 3 To adjust the distribution of magnetic lines of force (minimum magnetic flux) of the motor when the magnetic ring and the permanent magnet rotor are completely aligned axially.

[0011] Figure 4 The back EMF waveform when the magnetic ring is in different positions.

[0012] 1-Permanent magnet, 2-Magnetic guide block, 3-Stator core, 4-Armature winding, 5-Magnetic ring rotor. Detailed Implementation

[0013] To make the technical problems and solutions solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0014] Example:

[0015] like Figure 1 As shown, Figure 1 As shown, this invention discloses a permanent magnet motor with an axially shifting adjusting ring for reactive power compensation, comprising a permanent magnet rotor, an adjusting ring, and a stator armature. The adjusting ring is a circular ring structure and is stationary. The axial relative position between the adjusting ring and the permanent magnet rotor can be arbitrarily adjusted. The relative axial position between the permanent magnet rotor and the armature remains unchanged, and the output shaft of the permanent magnet rotor is unloaded.

[0016] Since the output shaft is unloaded, and without considering motor losses and rotor mechanical transients (or when the motor speed reaches steady state), the motor's input active power is always zero. The motor armature's three-phase windings are connected to the power grid. By mechanically adjusting the axial relative position of the adjusting ring and the permanent magnet rotor, and by short-circuiting the magnetomotive force of the magnets through the adjusting ring, the magnetic flux passing through the windings can be adjusted. This, in turn, allows adjustment of the motor's back electromotive force, thus enabling arbitrary adjustment of the motor's reactive power.

[0017] pass Figure 2 and 3 To explain the principle of magnetic flux regulation in detail: Figure 2As shown, at this point, the adjusting ring and the permanent magnet rotor are completely misaligned axially, the magnetomotive force of the magnet is not short-circuited, and the magnetic flux in the winding is at its maximum. Figure 3 As shown, at this point, the adjusting ring and the permanent magnet rotor are completely aligned axially, the magnetomotive force of the magnet is short-circuited, and the magnetic flux in the winding is at its minimum. The back electromotive force of the winding varies depending on the position of the adjusting ring, as shown below. Figure 4 As shown in the figure, the larger amplitude indicates that the magnetic adjustment ring and the permanent magnet rotor are completely misaligned axially.

[0018] Compared with conventional electrically excited synchronous phase-shifting motors, the motor described above has the advantages of simple structure, low cost, high efficiency and high reliability because it does not have a complicated excitation system for adjusting the excitation current of the motor, and the adjusting ring is a non-rotating part that is easy to adjust online. Therefore, it is very suitable as a reactive power compensation motor for power systems.

[0019] Figure 1 The motor shown has an external stator structure, with the permanent magnet rotor located between the external stator and the internal adjusting magnetic ring. The motor described in this invention, in addition to employing... Figure 1 In addition to the aforementioned topology, an inner stator motor topology can also be used, in which the stator is located on the inner side and the permanent magnet rotor is located between the outer adjusting magnetic ring and the inner stator.

[0020] As a preferred option, the motor stator adopts an internal stator design, which allows for convenient online adjustment of the axial relative position of the adjusting magnetic ring when it is externally mounted via a control mechanism.

[0021] The present invention has been described in detail above through specific and preferred embodiments. However, those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A permanent magnet motor with an axial translational magnetic ring for reactive power compensation, characterized in that, The motor consists of a permanent magnet rotor, a magnetic adjustment ring, and a stator armature. The magnetic adjustment ring is stationary, and the axial relative position between the magnetic adjustment ring and the permanent magnet rotor can be adjusted arbitrarily. The axial relative position between the permanent magnet rotor and the stator armature remains unchanged, and the output shaft of the permanent magnet rotor is unloaded.

2. The permanent magnet motor with axial translation of the adjusting ring for reactive power compensation according to claim 1, characterized in that, By mechanically adjusting the axial relative position of the adjusting ring and the permanent magnet rotor, the active power output of the motor can be made zero, while the reactive power can be adjusted arbitrarily.

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