CN205509809U - No bearing permanent magnet synchronous generator - Google Patents

Abstract

The utility model discloses a bearingless permanent magnet synchronous generator. The stator core is coaxially sleeved outside the permanent magnet rotor. The stator core is evenly provided with 36 stator slots along the circumferential direction. Each stator slot is arranged with inner and outer two-layer windings. The outer layer winding is a 2-pair pole generator winding with 3 stator slots per pole and each phase, and the inner layer winding is a 1-pair pole suspension force winding and 2 pair-pole excitation windings; the generator winding is clockwise according to A1+, B1‑, C1+ , A1‑, B1+, C1‑, A2+, B2‑, C2+, A2‑, B2+, C2‑phase arrangement, the suspension force windings are arranged clockwise in a+, b‑, c+, a‑, b+, c‑phase , the excitation windings are arranged clockwise in phases X1+, Y1‑, Z1+, X1‑, Y1+, Z1‑, X2+, Y2‑, Z2+, X2‑, Y2+, Z2‑, which improves the motor’s operating efficiency under special conditions. reliability.

Description

A bearingless permanent magnet synchronous generator

technical field

The utility model relates to the field of permanent magnet synchronous generators and bearingless motors, in particular to a bearingless permanent magnet synchronous generator used under the special working conditions of prime mover driving speed changes and external circuit load changes.

Background technique

The permanent magnet synchronous generator has many advantages such as simple structure, high efficiency, high power density, flexible topological structure, no need for brush structure, reliable operation, etc. The application of energy storage system electric generator integrated machine and many other occasions is becoming more and more extensive, which puts forward higher requirements for the reliability of generator operation. Due to the complex and changeable working environment of the generator, it is easy to cause a series of electrical or mechanical failures of its stator, rotor, bearing and other components, and the failure rate of the bearing is as high as about 40%. Bearings are the bottleneck to realize the high-speed and ultra-high-speed operation of the transmission system. Therefore, a bearingless motor is proposed to weaken the influence of bearing failure, prolong the service life of the bearing of the generator, and reduce maintenance costs.

At present, the ability of permanent magnet generator motors to adjust the magnetic field is very small. Generally, the magnetic field of permanent magnet motors is adjusted by adding auxiliary electric excitation. Therefore, there are some hybrid excitation generator models with different structures, such as: transverse flux hybrid excitation structure, double Disc hybrid excitation structure, etc. These motors are mostly hybrid magnetic circuit structures coupled with permanent magnet magnetic field and electric excitation magnetic field, such as: double salient pole hybrid excitation motor, brushless claw pole motor and hybrid excitation claw pole generator, etc. Most of these structures are improved for the rotor. The rotor is composed of a permanent magnet part for power generation and an electric excitation part for voltage regulation. The permanent magnet part and the electric excitation part are installed coaxially, and the air gap is changed by adjusting its excitation current. The magnitude of the magnetic flux achieves the purpose of voltage stabilization, but the assembly process is complicated, which increases the maintenance cost, increases the burden on the rotor, and reduces the power density.

The levitation force of the bearingless motor is the resultant force of Maxwell's force produced by the unbalanced magnetic field synthesized by the levitation force winding magnetic field and the torque winding magnetic field. Although the structure of the bearingless permanent magnet synchronous generator is simple and the operation is reliable, a series of problems such as the change of the given speed of the prime mover and the change of the electric load will be encountered when the generator is running, which will cause the magnetic field in the generator winding to change. Since the air gap magnetic field of the generator is difficult to adjust independently, the combined magnetic field of the generator winding and the levitation force winding of the bearingless permanent magnet synchronous generator changes. It is more difficult for generators to maintain constant voltage. For occasions with high stability requirements, methods such as voltage regulation by power electronic converters, double-rotor or double-stator voltage regulation must be used, which will increase costs and reduce dynamic performance.

Contents of the invention

In order to overcome the above-mentioned problems existing in existing generators, the utility model proposes a new type of high-performance bearingless permanent magnet synchronous generator, which improves the suspension performance and power generation quality of the generator under special working conditions.

The technical scheme adopted by the bearingless permanent magnet synchronous generator of the utility model is: it includes a stator core, a permanent magnet rotor and a rotating shaft, the stator core is coaxially sleeved outside the permanent magnet rotor, and the permanent magnet rotor is coaxially sleeved outside the rotating shaft. The magnetic rotor is composed of permanent magnets and fastening connectors. On the outer surface of the fastening connectors, four permanent magnets with radial magnetization and a pole pair number of 2 are evenly attached to the outer surface of the fastening connectors. The stator core is uniformly arranged along the circumferential direction. There are 36 stator slots, and each stator slot is equipped with inner and outer two-layer windings. The outer layer winding is a 2-pair pole generator winding with 3 stator slots per pole and each phase. The inner layer winding is a 1-pair pole suspension force winding and 2 pairs pole excitation winding.

Further, the generator windings are arranged clockwise in phases of A1+, B1-, C1+, A1-, B1+, C1-, A2+, B2-, C2+, A2-, B2+, and C2-, and the adjacent three slots form a At the incoming or outgoing end of the phase, the suspension force winding is arranged in a+, b-, c+, a-, b+, c- phases in the clockwise direction, and the excitation winding is arranged in the clockwise direction in X1+, Y1-, Z1+, X1- , Y1+, Z1-, X2+, Y2-, Z2+, X2-, Y2+, Z2- phase arrangement.

Furthermore, among the three stator slots where the A1+ phase of the generator winding is located, the inner layer winding in the first slot in the clockwise direction is the X1+ phase of the field winding, and the inner layer winding in the second and third slots The winding is the first a+ phase of the suspension force winding; the B1-phase of the generator winding is located in the three stator slots, the inner winding in the first slot in the clockwise direction is the Y1-phase of the excitation winding, the second and The inner layer winding in the third slot is the second a+ phase of the suspension force winding, and the adjacent first a+ phase and the second a+ phase are combined to form a complete a+ phase of the suspension force winding; the other phases of the inner layer winding The excitation windings occupying the first slot and the suspension force windings occupying the second and third slots are alternately arranged clockwise, and the suspension force windings in the two adjacent second and third slots.

The utility model has the advantages of:

1. There are inner and outer double-layer windings on the stator core of the utility model, and a set of excitation windings is added to the stator to compensate the synthetic magnetic field, which not only reduces mechanical noise, improves the reliability of the motor under special working conditions, but also has no friction, no Contact, no lubrication and low maintenance costs.

2. Because the number of pole pairs of the permanent magnet of the rotor and the number of pole pairs of the suspension force winding are different in the utility model, when there is no rotor eccentricity, the permanent magnet will not generate induced current in the suspension force winding, and the current of the suspension force winding will not generate rotation. Moment, that is, the levitation force control and power generation control of the bearingless permanent magnet synchronous generator are naturally decoupled.

3. The excitation winding of the utility model makes full use of the stator winding structure of the inner layer and adopts the same number of poles as the permanent magnet. When the given speed of the prime mover changes or the load of the external circuit of the generator changes, the induction The current change will lead to the change of the synthetic magnetic field. At this time, the corresponding current is passed through the excitation winding to compensate the change of the synthetic magnetic field, which can make the bearingless permanent magnet synchronous generator continue to operate stably.

Description of drawings

Fig. 1 is the axial sectional schematic diagram of a kind of bearingless permanent magnet synchronous generator of the utility model;

Fig. 2 is an enlarged view of the radial section after removing the casing in Fig. 1 and a schematic diagram of the winding arrangement;

Fig. 3 is a schematic wiring diagram of each winding horizontally expanded in Fig. 2;

Fig. 4 is a schematic diagram of the connection of each winding in Fig. 3 to the load circuit and the drive power circuit;

Fig. 5 is a schematic diagram of the suspension force and the spatial distribution structure of the motor magnetic field when the utility model works;

Fig. 6 is a schematic diagram of magnetic field strengthening composed of compensating windings when the utility model works;

Fig. 7 is a schematic diagram of weakening of the magnetic field formed by the compensating winding when the utility model works.

In the figure: 1-casing, 2-stator core, 3-generating winding, 4-suspension force winding, 5-excitation winding, 6-surface-mounted permanent magnet with radial magnetization, 7-radial displacement sensor, 8 - datum ring, 9-left end cover, 10-right end cover, 11-spare bearing, 12-aligning bearing, 13-rotating shaft, 14-photoelectric code disc, 15-fastening connector connecting permanent magnet and rotating shaft.

detailed description

Referring to Fig. 1, the utility model comprises casing 1, stator iron core 2, permanent magnet rotor and rotating shaft 13, and outermost is casing 1, and the axial left end of casing 1 fixes left end cap 9, and the axial right end fixes right end cap 10. A rotating shaft 13 is installed at the center of the casing 1 , and the rotating shaft 13 is coaxially connected with the casing 1 . There is a stator core 2 and a permanent magnet rotor inside the casing 1, the stator core 2 is fixedly connected to the inner wall of the casing 1, the permanent magnet rotor is coaxially sleeved outside the rotating shaft 13, and the stator core 2 is coaxially sleeved outside the permanent magnet rotor, which belongs to the outer stator Inner rotor structure. There is a radial air gap between the stator core 2 and the permanent magnet rotor. The permanent magnet rotor is composed of permanent magnets 6 and fastening connectors 15 , and the permanent magnets 6 are radially magnetized and surface-attached on the fastening connectors 15 . The fastening connector 15 fixedly connects the permanent magnet 6 and the rotating shaft 13 as a whole. The left end of the fastening connector 15 is supported on the left end cover 9 through the self-aligning bearing 12, and the right end of the fastening connector 15 is supported on the right end cover 10 through the backup bearing 11. When the generator is not working, the backup bearing 11 plays a supporting role . The stator core 2 and the permanent magnet rotor are installed in the axial middle of the rotating shaft 13. There are four radial displacement sensors 7 in the space at the left end of the stator core 2 in the casing 1, and the radial displacement sensors 7 are installed on the reference ring 8. The ring 8 is coaxially fixedly sleeved on the rotating shaft 13 . There are two inner and outer windings on the stator core 2, the outer winding is the power generation winding 3, the inner winding is the suspension force winding 4 and the excitation winding 5, the suspension force winding 4 is used to generate radial suspension force, and the excitation winding 5 is used to compensate magnetic field.

Referring to FIG. 2 , four radially magnetized permanent magnets 6 are surface-mounted on the outer surface of the fastening connector 15 , and the four permanent magnets 6 are evenly arranged along the circumferential direction to form a structure with two poles. There are 36 stator slots evenly arranged in the stator core 2 along the circumferential direction, and inner and outer two-layer windings are arranged in each stator slot, and the winding adopts a distributed inner and outer two-layer arrangement. The outer layer winding is a distributed power generation winding 3 with 3 stator slots per pole and phase. A2-, B2+, and C2- are arranged in phases, and the three adjacent slots are the incoming or outgoing terminals of one phase. This arrangement makes the generator winding 3 have two pairs of poles, and the poles of the permanent magnet 6 in the permanent magnet rotor. Like the logarithm, it can generate electricity by induction. The inner layer winding is the suspension force winding 4 and the excitation winding 5, the suspension force winding 4 is arranged in a+, b-, c+, a-, b+, c- phases in the clockwise direction, and the excitation winding 5 is arranged in the clockwise direction according to the winding X1+, Y1-, Z1+, X1-, Y1+, Z1-, X2+, Y2-, Z2+, X2-, Y2+, Z2- phase arrangement.

Among the three stator slots where the A1+ phase of the generator winding 3 is located, the inner layer winding in the first clockwise slot is the X1+ phase of the field winding 5, and the inner layer windings in the second and third slots are a+ phase of suspension force winding 5. In the three stator slots where the generator winding B1-phase is located, the inner winding in the first slot in the clockwise direction is the Y1-phase of the excitation winding 5, and the inner windings in the second and third slots are still The a+ phase of the suspension force winding, which forms two adjacent a+ phases with the a+ phase in the stator slot where the A1+ phase is located, and the two adjacent a+ phases are combined to form the a+ phase of the complete suspension force winding 5 . The arrangement of the other phases of the inner winding is analogous, and the field winding 5 occupying the first slot in the clockwise direction and the levitation force winding 4 occupying the second and third slots are staggered in this way. The levitation force winding 4 in two adjacent second and third slots form a phase, and the adjacent two second and third slots are the incoming or outgoing ends of the levitation force winding 4 phase, so, The pole pairs of the formed one-pair levitation force winding 4 and the power generation winding 3 differ by 1, which satisfies the levitation principle of the bearingless motor. The excitation winding 5 forms the same two pairs of poles as the generating winding 3 and the permanent magnet 6, which can compensate and weaken the main magnetic field.

Expand the windings in the utility model horizontally, and you can intuitively understand the wiring arrangement and current flow of the windings. See Figure 3. The generator winding 3 takes phase A as an example, and the windings of every three stator slots are the incoming or outgoing wires of one phase. At the end, the windings are arranged clockwise in phases of A1+, B1-, C1+, A1-, B1+, C1-, A2+, B2-, C2+, A2-, B2+, and C2-. The wiring of phase A is to enter the line from the A1+ side, exit from the adjacent A1- side, and then wind it to the A2+ end, and exit from the adjacent A2- end. The wiring principle of phase B and phase C is the same as that of phase A. Then A1+, B1+, and C1+ are connected together as the neutral point of the generator winding 3, and the A2-, B2-, and C2-phases are respectively connected to the three phases A, B, and C of the three-phase PWM rectifier bridge shown in Figure 4. A bridge arm, the current induced by the generator flows into the PWM rectifier bridge from the neutral point of the generator winding 3 to supply the load with electricity.

The levitation force winding 4 takes phase a as an example, and is arranged clockwise according to a+, b-, c+, a-, b+, c-. The suspension force winding 4 is connected to the first three-phase bridge inverter circuit shown in FIG. The wiring principle is the same as phase a. Connect a-, b-, c- terminals together as the neutral point of the suspension force winding 4, and a+, b+, c+ are respectively connected to a, b of the first three-phase bridge inverter circuit shown in Figure 4 , c three bridge arms, the current flows from the first three-phase bridge inverter circuit to the suspension force winding 4 .

The excitation winding 5 takes the X phase as an example, and is arranged in the clockwise direction according to X1+, Y1-, Z1+, X1-, Y1+, Z1-, X2+, Y2-, Z2+, X2-, Y2+, Z2-phase. The excitation winding 5 is connected to the second three-phase bridge inverter circuit shown in Fig. 4, the X-phase connection of the second three-phase inverter bridge circuit is connected, the wire enters from the X1+ side, and the wire exits from the adjacent X1- side, and then The wire is wound into the X2+ terminal, and the wire is output from the adjacent X2- terminal. The wiring principle of the Y phase and Z phase of the excitation winding 5 is the same as that of the X phase. The X2-, Y2-, Z2- terminals of the excitation winding 5 are connected together as the neutral point of the excitation winding 5, and X1+, Y1+, Z1+ are respectively connected to the second three-phase bridge inverter circuit shown in Figure 4 For the three bridge arms X, Y, and Z, the current flows from the second three-phase bridge inverter circuit to the excitation winding 5 .

In Figure 4, C is a capacitor, which means a capacitive load, and R is an inductance, which means an inductive load. V1-V6 in the PWM rectifier bridge and the two bridge inverter circuits are controllable switches, and VD1-VD6 are freewheeling diodes.

When the utility model works, the principle of suspension is shown in Figure 5. During operation, the centering operation of the rotor is to adjust the current signal of a given suspension winding by detecting the feedback signal of the radial displacement of the rotor. Taking phase A of the generator winding 3 and phase a of the levitation force winding 4 as an example, a 4-pole power generation winding 3 and a 2-pole levitation force winding 4 are wound in the stator slots. When the current of the first three-phase bridge inverter circuit shown in Figure 4 is not passed into the suspension force winding 4, the induced magnetic field generated by the generator winding 3 and the 4-pole air-gap magnetic flux ϕ _m synthesized by the permanent magnet 6 are balanced , the resultant radial force is zero. The air-gap magnetic flux respectively passes through components such as the generator winding 3, the stator core 2, the air gap, the permanent magnet 6, and the rotating shaft 13, and divides the generator into four parts in space. When the positive current of the first three-phase bridge inverter circuit shown in FIG. 4 is passed through the levitation force winding 4, a 2-pole magnetic flux ϕ _α will be generated. The magnetic flux respectively passes through the suspension force winding 4, the stator core 2, the air gap, the permanent magnet 6, and the rotating shaft 13, and divides the generator into two parts in space. This results in an increase in the air-gap flux density at the air gap on one side of the rotor in the horizontal direction and a decrease in the air-gap flux density at the air gap on the other side of the rotor radial horizontal direction, resulting in a Maxwell force F _m along, for example, the negative direction of the x -axis , to make the rotor shift towards the negative direction of the x -axis (the x -axis in the horizontal direction and the y -axis in the vertical direction are omitted in Figure 5). If the first three-phase bridge inverter circuit in FIG. 4 is supplied with currents in opposite directions, a Maxwell force along the positive direction of the x -axis will be generated. Similarly, the Maxwell force along the y -axis direction can be obtained by passing corresponding currents in other phase windings. The bearingless permanent magnet synchronous motor of the utility model is not only subjected to the radial force of Maxwell, but also subjected to the radial force of Lorentz. According to the left-hand rule, the suspension force winding 4 is subjected to the Lorentz force F ₁ , the generating winding 3 is subjected to the Lorentz force F ₂ , and the corresponding forces on the rotor surface are the reaction forces F s ₁ and F s ₂ . It can be seen from Figure 5 that the direction of the resultant force of the two parts of the Lorentz force is the horizontal direction, that is, the rotor is subjected to the radial levitation force in the x -axis direction. Through the closed-loop control of the above two radial forces and the levitation force winding current, the stable levitation of the generator rotor can be realized.

The power generation principle of the utility model is the same as that of the ordinary permanent magnet synchronous generator. The prime mover is coaxially connected with the bearingless permanent magnet synchronous generator of the present invention. Driven by the prime mover, the rotor rotates to generate a changing induced magnetic field, and the generating winding cuts the magnetic induction. The line generates a three-phase induced current. Since the A2-, B2-, and C2-phases of the generator winding 3 are all connected to the A, B, and C bridge arms of the PWM rectifier bridge shown in Figure 4, the current induced by the generator will flow into the PWM rectifier bridge from the neutral point to supply the load Electricity is used to generate a generating voltage at both ends of the load for storage of electric energy.

The excitation principle is shown in Fig. 6 and Fig. 7. When the inverter circuit controlling the field winding 5 in Fig. 4 is energized, the magnetic field ϕ _e generated by the field winding 5 respectively passes through the field winding 5, the stator core 2, the air gap, and the permanent magnet 6 These components of rotating shaft 13 divide the generator into four parts equally with the generator winding 3 in space, which is also the principle that the utility model can compensate or weaken the main magnetic field. When the combined magnetic field of the generating winding 3 and the levitation force winding 4 is weakened, it is supplemented with an enhanced excitation magnetic field; on the contrary, a reverse excitation magnetic field is given to weaken the combined magnetic field of the generating winding 3 and the levitation force winding 4. In Fig. 6, the magnetic field of the field winding 5 is in the same direction as the synthetic magnetic field, which is expressed as the compensation effect of the field winding 5 on the synthetic magnetic field; in Fig. 7, the magnetic field of the field winding 5 is opposite to the synthetic magnetic field, which is represented as the weakening of the synthetic magnetic field by the field winding 5 effect. Taking the generator winding 3 of phase A and the excitation winding 5 of phase X as examples, when the given rotational speed of the prime mover changes, the change of the induced current in the generator winding 3 will lead to the change of the synthetic magnetic field, which will affect the levitation force performance and power generation quality. By detecting the signal of the rotor angular position and the given speed of the prime mover, the input current of the third three-phase inverter circuit shown in Figure 4 is adjusted to control the increase or decrease of the current in the field winding 5, thereby stabilizing the internal magnetic field of the generator. . When the load of the generator changes, the current in the generator winding 3 also changes, which affects the synthesized magnetic field. At this time, by detecting the signals of the rotor position angle and the generated voltage, the input current of the second three-phase inverter circuit shown in FIG. 4 is adjusted to control the increase or decrease of the current in the field winding 5, thereby stabilizing the internal synthetic magnetic field of the generator. Due to the existence of the excitation winding 5 in the utility model, both the suspension performance and the power generation quality are improved.

Claims (6)

1. A bearingless permanent magnet synchronous generator, comprising a stator core, a permanent magnet rotor and a rotating shaft, the stator core is coaxially sleeved outside the permanent magnet rotor, the permanent magnet rotor is coaxially sleeved outside the rotating shaft, and the permanent magnet rotor consists of permanent magnets and Composed of fastening connectors, its features are: the outer surface of the fastening connector is uniformly attached with four radially magnetized permanent magnets with a pole pair number of 2 along the circumferential direction, and the stator core is uniformly arranged with 36 permanent magnets along the circumferential direction. Stator slots, inner and outer two-layer windings are arranged in each stator slot, the outer layer windings are 2 pairs of poles generating windings with 3 stator slots per pole and each phase, and the inner layer windings are 1 pair of pole suspension force windings and 2 pairs of poles excitation winding. 2. A bearingless permanent magnet synchronous generator according to claim 1, characterized in that: the generator windings are clockwise according to A1+, B1-, C1+, A1-, B1+, C1-, A2+, B2-, C2+ , A2-, B2+, and C2- are arranged in phases, and the adjacent three slots are the incoming or outgoing ends of one phase, and the suspension force windings are arranged clockwise according to a+, b-, c+, a-, b+, c- Arranged in phases, the excitation windings are arranged clockwise in X1+, Y1-, Z1+, X1-, Y1+, Z1-, X2+, Y2-, Z2+, X2-, Y2+, Z2- phases. 3. A bearingless permanent magnet synchronous generator according to claim 2, characterized in that: in the three stator slots where the A1+ phase of the generating winding is located, the inner layer winding in the first clockwise slot is The X1+ phase of the field winding, the inner winding in the second and third slots is the first a+ phase of the suspension force winding; the B1- phase of the generator winding is located in the 3 stator slots, the first one in the clockwise direction The inner winding in the slot is the Y1-phase of the excitation winding, the inner winding in the second and third slots is the second a+ phase of the suspension force winding, the adjacent first a+ phase and the second The a+ phase is combined to form a complete a+ phase of the suspension force winding; the other phases of the inner layer winding are arranged clockwise in the excitation winding occupying the first slot and the suspension force winding occupying the second and third slots in a staggered arrangement, adjacent to each other The suspension force windings in the two second and third slots form one phase, and the two adjacent second and third slots are the incoming or outgoing terminals of one phase of the suspension force winding. 4. A kind of bearingless permanent magnet synchronous generator according to claim 3, it is characterized in that: the suspension force winding is connected to the first three-phase inverter circuit, and the current flows from the first three-phase bridge inverter circuit to the suspension force winding, The line enters from the a+ side and the line exits from the a- side. The wiring principle of phase b and phase c is the same as that of phase a. The a-, b-, and c- terminals are connected together as the neutral point, and the a+, b+, and c+ phases are respectively The three bridge arms of the first three-phase bridge inverter circuit are connected. 5. A kind of bearingless permanent magnet synchronous generator according to claim 3, it is characterized in that: the field winding is connected to the second three-phase bridge inverter circuit, and the current flows to the field winding by the second three-phase bridge inverter circuit, Enter the wire from the X1+ side, exit from the adjacent X1- side, and then wind it to the X2+ end to enter the wire, and exit from the adjacent X2- end. The wiring principle of the Y phase and Z phase of the excitation winding is the same as that of the X phase. The X2-, Y2-, Z2- terminals of the winding are connected together as a neutral point, and the X1+, Y1+, Z1+ terminals are respectively connected to the three bridge arms of the second three-phase bridge inverter circuit. 6. A bearingless permanent magnet synchronous generator according to claim 3, characterized in that: phase A of the generator winding enters the line from the A1+ side, exits from the adjacent A1- side, and then winds to the A2+ end to enter the line , from the adjacent A2- terminal, the wiring principle of B phase and C phase is the same as that of A phase, A1+, B1+, C1+ are connected together as a neutral point, and A2-, B2-, C2-phases are respectively connected to three The three bridge arms of the phase PWM rectifier bridge, the current generated by induction flows into the PWM rectifier bridge from the neutral point.