CN113036972B

CN113036972B - Wind power generation system

Info

Publication number: CN113036972B
Application number: CN202110283076.XA
Authority: CN
Inventors: 王文婷; 吴立建; 闻汇; 李华阳; 李京泽; 钟云龙
Original assignee: Zhejiang University ZJU; Shanghai Electric Wind Power Group Co Ltd
Current assignee: Zhejiang University ZJU; Shanghai Electric Wind Power Group Co Ltd
Priority date: 2021-03-16
Filing date: 2021-03-16
Publication date: 2022-09-13
Anticipated expiration: 2041-03-16
Also published as: CN113036972A

Abstract

The invention discloses a wind power generation system, which comprises a wind power generator, wherein the wind power generator comprises at least one stator unit distributed along the circumference, each stator unit comprises at least one stator tooth group distributed along the circumference, each stator tooth group comprises at least one stator tooth distributed along the circumference, and each stator tooth is wound with at least two coils; the number of phases of each power conversion circuit is the same, and the power conversion circuits are used for converting the frequency of the electric energy output by the wind driven generator; the coils belonging to the same stator tooth group are at least connected with different phases of different power conversion circuits, and the total number of the coils connected among different phases of the same power conversion circuit is consistent. The invention can avoid motor vibration, harmonic impact on a power grid, surge of eddy current loss and torque fluctuation caused by unbalance, improve the efficiency of the wind driven generator in fault-tolerant operation and reduce the risk of demagnetization of the permanent magnet under the condition of short circuit.

Description

Wind power generation system

Technical Field

The invention relates to the technical field of wind power generation, in particular to a wind power generation system.

Background

The high-reliability and maintenance-friendly wind generating set is a constant topic in the wind power industry, is particularly important for offshore wind power with severe environment and poor accessibility, can obviously reduce operation and maintenance cost, and simultaneously increases generating capacity. According to statistical data, the fault of the converter is one of main fault reasons of the fan, the downtime caused by the fault accounts for a certain time, and the fault is a key phoneme which restricts the availability of the wind turbine generator.

Redundancy and fault tolerance are two types of methods for improving the reliability of the wind turbine generator. The number of times of shutdown and time caused by converter faults can be effectively reduced by additionally arranging the backup converter, but the defects of cost increase of the converter, weight increase of a unit, increase of the volume required by a cabin or a tower bottom and the like exist. For wind power applications where the power costs are extremely sensitive, the redundant converter scheme is not a preferred option. On the other hand, a proper generator/converter topology is constructed, so that the power generation system has a fault-tolerant operation function, and the technical scheme is high in feasibility. When one of the converters fails, the generator winding connected with the converter is cut off, and the rest generator windings continue to work, so that the generator can continue to generate power in a mode of reducing power or losing partial performance, and risk loss caused by failure of the converters is greatly reduced. However, the design of fault-tolerant generator/converter topology faces multiple challenges, and one of the main difficulties is to consider the performance of normal operation and fault-tolerant operation.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a wind power generation system.

The invention solves the technical problems through the following technical scheme:

the present invention provides a wind power generation system, comprising:

the wind power generator comprises at least one stator unit distributed along the circumference, each stator unit comprises at least one stator tooth group distributed along the circumference, each stator tooth group comprises at least one stator tooth distributed along the circumference, and each stator tooth is wound with at least two coils;

the phase number of each power conversion circuit is the same, and the power conversion circuits are used for converting the frequency of the electric energy output by the wind driven generator;

the coils belonging to the same stator tooth group are at least connected with different phases of different power conversion circuits, and the total number of the coils connected among different phases of the same power conversion circuit is consistent.

Optionally, the total number of coils connected by different power conversion circuits is the same or different.

Alternatively, the same number of coils are wound on different stator teeth belonging to the same stator tooth group.

Alternatively, the number of power conversion circuits to which coils wound in different stator tooth groups belonging to one stator unit are connected is the same or different.

Optionally, the number of the power conversion circuits connected to the coils wound on different stator teeth belonging to the same stator tooth group is the same or different.

Optionally, the number of coils wound on one stator tooth is less than the number of the power conversion circuits.

Optionally, in a stator tooth group, the stator teeth are sequentially arranged along the circumferential direction, the coil wound at the second position on each stator tooth and the coil wound at the first position on the next stator tooth are connected with the same power conversion circuit, and the coil wound at each of the other positions on each stator tooth and the coil wound at the corresponding previous position on the next stator tooth are connected with the same power conversion circuit.

Optionally, in a stator tooth group, the stator teeth are sequentially arranged along the circumferential direction, the coil wound at the first position on each stator tooth and the coil wound at the second position on the next stator tooth are connected with the same power conversion circuit, and the coil wound at each of the other positions on each stator tooth and the coil wound at the corresponding next position on the next stator tooth are connected with the same power conversion circuit.

Optionally, the number of coils wound on one stator tooth is the same as the number of the power conversion circuits.

Optionally, the coil wound at the first position on each stator tooth in the target stator unit and the coil wound at the last position on the stator tooth with the same sequencing position in the same circumferential direction in the next stator unit are connected to the same power conversion circuit, the coil wound at each remaining position on each stator tooth in the target stator unit and the coil wound at the corresponding previous position on the stator tooth with the same sequencing position in the same circumferential direction in the next stator unit are connected to the same power conversion circuit, wherein the target stator unit is any one of all the stator units sequentially sequenced in the circumferential direction in the wind turbine generator.

Alternatively, if the coils in the stator slots are distributed in sequence along the radial direction, the position closest to the slot tops of the stator slots is the first position, and the position farthest from the slot tops of the stator slots is the last position.

Alternatively, if the coils in the stator slots are distributed in sequence along the circumferential direction, the position closest to the stator teeth is the first position, and the position farthest from the stator teeth is the last position.

Optionally, each stator unit comprises the same number of stator tooth groups and/or each stator tooth group comprises the same number of stator teeth.

Alternatively, the coils in the stator slots are distributed in sequence in the radial direction or in sequence in the circumferential direction.

Optionally, the wind power generator further includes a rotor, and n stator teeth of the x stator tooth groups included in each stator unit correspond to m permanent magnets on the rotor, where x, n, and m are positive integers and n is less than m, a pole pitch τ of the permanent magnets is the same as a slot pitch of the stator slots, and distances between the stator tooth groups are equal and are (m-n) × τ/x.

Optionally, the windings of the wind turbine are distributed windings or concentrated windings.

The positive progress effects of the invention are as follows:

(1) at least two power conversion circuits are mutually redundant, when one power conversion circuit or a coil connected with one phase or multiple phases of the power conversion circuit fails, the corresponding power conversion circuit can be cut off, and the residual power conversion circuit and a winding connected with the residual power conversion circuit can work normally to continue to output power.

(2) Because the total number of the coils connected between different phases of the same power conversion circuit is consistent, all the remaining coils are still balanced in a fault-tolerant mode, compared with the traditional mode, the harmonic component generated by an armature magnetic field is reduced or even reduced, the vibration of a motor, the harmonic impact on a power grid, the surge of eddy current loss and the torque fluctuation caused by unbalance are avoided, and the efficiency of the wind driven generator during fault-tolerant operation is improved.

(3) Because a plurality of coils are wound on all the stator teeth belonging to the same stator tooth group, compared with the traditional coil distribution form, the interphase mutual inductance is larger, the current surge caused by faults can be inhibited, and the risk of demagnetization of the permanent magnet under the fault condition is obviously reduced.

(4) Because each stator tooth is wound with at least two coils, the number of turns of the traditional single coil is shared, the counter electromotive force is small, the voltage born by insulation is small, and the service life of the insulation can be effectively prolonged. Thinner insulation at low insulation levels may be used, providing more space in the slot to the conductor to produce more torque; on the other hand, the reduction of the insulation thermal resistance makes the heat on the winding more easily transferred to the stator core, thereby simultaneously reducing the temperature rise of the winding.

Drawings

Fig. 1 is a schematic circuit topology structure diagram of a wind power generation system according to embodiment 1 of the present invention.

Fig. 2 is a schematic view of a coil distributed in a radial direction according to embodiment 1 of the present invention.

Fig. 3 is a schematic diagram of coils distributed along the circumferential direction according to embodiment 1 of the present invention.

Fig. 4 is a schematic diagram of a coil distribution manner of the first stator unit and the second stator unit provided in embodiment 1 of the present invention.

Fig. 5 is a schematic diagram of another coil distribution manner of the first stator unit and the second stator unit provided in embodiment 1 of the present invention.

Fig. 6 is a schematic diagram of an integer slot single-layer distributed winding provided in embodiment 1 of the present invention.

Fig. 7 is a schematic diagram of a coil distribution manner of a first stator unit according to embodiment 1 of the present invention.

Fig. 8 is a schematic diagram of a coil distribution manner of a first stator unit according to embodiment 2 of the present invention.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

Example 1

The embodiment provides a wind power generation system which comprises a wind power generator and at least two power conversion circuits, wherein the number of phases of each power conversion circuit is the same, and the wind power generator is connected with each power conversion circuit. The power conversion circuit is used for receiving the electric energy output by the wind driven generator and performing frequency conversion and output. The at least two power conversion circuits are redundant, when one of the power conversion circuits or a coil connected with the power conversion circuit fails, the corresponding power conversion circuit can be cut off, and the rest of the power conversion circuits work normally and can continue to output power.

FIG. 1 is a schematic circuit topology for illustrating a wind power system. The wind power generation system shown in fig. 1 includes three power conversion circuits, specifically, a power conversion circuit 1, a power conversion circuit 2, and a power conversion circuit 3. The power conversion circuit 1 includes a1 phase, B1 phase, and C1 phase, the power conversion circuit 2 includes a2 phase, B2 phase, and C2 phase, and the power conversion circuit 3 includes A3 phase, B3 phase, and C3 phase. Each power conversion circuit comprises a machine side converter and a grid side converter, wherein the machine side converter comprises a rectifier and is used for converting alternating current output by the wind driven generator into direct current. The grid-side converter comprises an inverter for converting the direct current into a power frequency alternating current for grid connection.

In the wind power generation system provided by this embodiment, the wind power generator includes at least one stator unit distributed along a circumference, each stator unit includes at least one stator tooth group, each stator tooth group includes at least one stator tooth, and at least two coils are wound on each stator tooth, where the coils belonging to the same stator tooth group are at least connected to different phases of different power conversion circuits, and the total number of the coils connected between different phases of the same power conversion circuit is the same.

In the present embodiment, the coils connected to the same power conversion circuit on the stator teeth belong to one coil. For example, a coil wound around one stator tooth is connected to phase a of power conversion circuit 1 and phase a of power conversion circuit 2, and two coils are wound around the stator tooth.

In an alternative embodiment, the total number of coils connected by different power conversion circuits is the same.

In an alternative embodiment, the total number of coils connected to different power conversion circuits is different.

In an alternative embodiment, the same number of coils is wound around different stator teeth belonging to the same stator tooth group.

In an alternative embodiment, different stator teeth belonging to the same stator tooth group are wound with different numbers of coils.

In an alternative embodiment, the number of power conversion circuits connected to coils wound on different stator teeth belonging to the same stator tooth group is the same. In an alternative embodiment, the number of power conversion circuits connected to coils wound on different stator teeth belonging to the same stator tooth group is different.

In an alternative embodiment, the number of power converter circuits connected to the coils wound in different stator tooth groups belonging to a stator unit is the same.

In an alternative embodiment, the number of power converter circuits connected to the coils wound in different stator tooth groups belonging to a stator unit is different.

In an alternative embodiment, the number of coils wound on one stator tooth is the same as the number of power conversion circuits. In an alternative embodiment, each stator unit comprises the same number of stator tooth groups.

In an alternative embodiment, each stator tooth set includes the same number of stator teeth.

In an alternative embodiment, the coils in the stator slots may be distributed radially, as shown in fig. 2. In an alternative embodiment, the coils in the stator slots may also be distributed circumferentially, as shown in fig. 3.

In an alternative embodiment, the number of coils wound on each stator tooth is less than the number of phases of the power conversion circuit.

In this embodiment, the coils wound on the same stator tooth are electrically isolated from each other and are not connected to each other. The coils of the whole wind driven generator form n sets of m-phase windings which are respectively and correspondingly connected to m phases of the n power conversion circuits.

In an alternative embodiment, the windings of the wind turbine are distributed windings or concentrated windings.

In the first stator unit and the second stator unit shown in fig. 4, the winding of the coils on the stator teeth is centralized winding, that is, the span of the coils wound on the stator teeth is 1.

In the embodiment, at least two coils are wound on each stator tooth, and the coils in each stator tooth group are at least connected with different power conversion circuits, so that after one power conversion circuit is cut off, the rest coils are still symmetrically distributed on the circumference of the wind driven generator, compared with the case that a 1-phase coil is wound on one stator tooth, the wind driven generator still can keep phase-to-phase balance, and the harmonic component generated by an armature magnetic field is unchanged, so that the motor vibration, the harmonic impact on a power grid, the surge of eddy current loss and the torque fluctuation caused by unbalance are avoided, after the fault power conversion circuit is cut off, the eddy current loss is obviously weakened due to the weakening of the armature magnetic field, and the efficiency of the wind driven generator in fault-tolerant operation is improved.

In addition, because the coils in each stator tooth group are respectively connected with different power conversion circuits, compared with the traditional coil distribution mode, the interphase mutual inductance is larger, when a short circuit occurs in a certain phase, the short-circuit current can cause the current in other coils on the same stator tooth to increase through the mutual inductance, the armature magnetic field generated by the increased current of the normal coil is opposite to the magnetic field generated by the short-circuit current, and in turn, the size of the short-circuit current and the armature magnetic field generated by the armature magnetic field opposite to the direction of the permanent magnet magnetic field are inhibited through the mutual inductance, and the risk of permanent magnet demagnetization under the short-circuit condition is obviously reduced.

For the temperature of the whole machine, because the coil works on each stator tooth under the fault-tolerant condition, compared with the traditional coil distribution mode, the temperature distribution of the whole machine is more uniform. The number of turns of each coil wound on the stator teeth in the embodiment is less than that of the coil wound on the 1-phase coil on the traditional stator teeth, the number of turns of the coil working on each stator tooth is less under the fault-tolerant condition, the temperature rise on each stator tooth is low under the condition that the current is not changed, the condition that the local temperature is too high or too low cannot occur, and the burden of a heat dissipation system is lightened.

Because the turns of the traditional single coil are shared on each stator tooth, the turns of each coil are few, the counter electromotive force is small, the requirement on insulation is low, and compared with the traditional mode, the insulation can be thinner, on one hand, more space in the groove is saved for supplying winding distribution, the winding resistance is reduced, and more current can be supplied to generate larger torque under the same copper consumption. On the other hand, the thermal resistance of the insulation part is obviously reduced along with the thickness of the insulation part, and the heat on the winding can be more easily conducted to the surface of the stator core and then taken away by the cooling medium, so that the average temperature rise and the maximum temperature rise of the winding are simultaneously reduced. In addition, no matter in normal operation or fault-tolerant operation, the insulation service life can be effectively prolonged due to the fact that the voltage borne by the insulation is small.

In an alternative embodiment, the number of coils wound on one stator tooth is less than the number of power conversion circuits.

In an alternative embodiment, if the coils in the stator slots are distributed in a radial sequence, the position closest to the slot tops of the stator slots is the first position, and the position farthest from the slot tops of the stator slots is the last position. In an alternative embodiment, if the coils in the stator slots are distributed in sequence in the circumferential direction, the position closest to the stator teeth is the first position, and the position farthest from the stator teeth is the last position.

In an alternative embodiment, in a stator tooth group, the coils wound at the second position on each stator tooth and the coils wound at the first position on the next stator tooth are connected to the same phase of the same power conversion circuit, and the coils wound at each of the other positions on each stator tooth and the coils wound at the corresponding previous position on the next stator tooth are connected to the same phase of the same power conversion circuit.

In one specific example, a wind power generation system includes a 48-pole, 54-slot three-phase wind turbine and 3 power conversion circuits, each capable of outputting 3-phase current. The three-phase current output by each power conversion circuit is represented by A, B, C, a1, B1 and C1 respectively represent a phase a, B phase and C phase of the power conversion circuit 1, a2, B2 and C2 respectively represent a phase a, B phase and C phase of the power conversion circuit 2, and A3, B3 and C3 respectively represent a phase a, B phase and C phase of the power conversion circuit 3. The wind driven generator comprises 6 stator units distributed along the circumference, namely a first stator unit, a second stator unit, a third stator unit, a fourth stator unit, a fifth stator unit and a sixth stator unit.

Fig. 4 is a schematic diagram for illustrating a coil distribution pattern of the first stator unit and the second stator unit. As shown in fig. 4, the first stator unit includes 3 stator tooth groups. Each stator tooth group comprises 3 circumferentially adjacent stator teeth. And 2 coils are wound on each stator tooth by adopting double-layer concentrated windings. Specifically, the method comprises the following steps: the coils in the stator tooth group 1 are connected with at least the phases A and B of 3 power conversion circuits; the coils in the stator tooth group 2 are connected with at least the phases B and C of the 3 power conversion circuits, and the coils in the stator tooth group 3 are connected with at least the phases C and A of the 3 power conversion circuits; the coils wound at the positions 2 and 1 on the stator teeth 1 and 2 are connected with the A of the power conversion circuit 2, the coils wound at the positions 2 and 2 on the stator teeth 2 and the coils wound at the positions 1 on the stator teeth 3 are connected with the A of the power conversion circuit 3, the coils wound at the positions 2 and 2 on the stator teeth 3 and the coils wound at the positions 1 on the stator teeth 4 are connected with the B of the power conversion circuit 1, the coils wound at the positions 2 and 2 on the stator teeth 4 and the coils wound at the positions 1 on the stator teeth 5 are connected with the B of the power conversion circuit 2, the coils wound at the positions 2 and 2 on the stator teeth 5 and the coils wound at the positions 1 on the stator teeth 6 are connected with the B of the power conversion circuit 3, the coils wound at the positions 2 and 2 on the stator teeth 7 are connected with the C of the power conversion circuit 1, the coils wound at the positions 2 and 2 on the stator teeth 8 and the coils wound at the positions 1 on the stator teeth 7 are connected with the C of the power conversion circuit 2 The coil wound at the position 2 on the stator tooth 8 and the coil wound at the position 1 on the stator tooth 9 are both connected with the C of the power conversion circuit 3, and the coil wound at the position 2 on the stator tooth 9 and the coil wound at the position 1 on the stator tooth 1 are both connected with the A of the power conversion circuit 1.

In an alternative embodiment, in a stator tooth group, the stator teeth are sequentially arranged along the circumferential direction, the coil wound at the first position on each stator tooth and the coil wound at the second position on the next stator tooth are connected with the same one of the same power conversion circuit, and the coil wound at each of the other positions on each stator tooth and the coil wound at the corresponding next position on the next stator tooth are connected with the same one of the same power conversion circuit.

As shown in fig. 4, the second stator unit includes 3 stator tooth groups. Each stator tooth set comprises 3 circumferentially adjacent stator teeth. And 2 coils are wound on each stator tooth by adopting double-layer concentrated windings. Specifically, the method comprises the following steps: the coils in the stator tooth group 1 are connected with at least the phases A and B of 3 power conversion circuits; the coils in the stator tooth group 2 are connected with at least the phases B and C of the 3 power conversion circuits, and the coils in the stator tooth group 3 are connected with at least the phases C and A of the 3 power conversion circuits; the coils wound at the positions 1 and 2 on the stator teeth 2 are connected with the A of the power conversion circuit 2, the coils wound at the positions 1 and 2 on the stator teeth 2 and 3 are connected with the A of the power conversion circuit 3, the coils wound at the positions 1 and 2 on the stator teeth 3 and 4 and B of the power conversion circuit 1 are connected with the B of the power conversion circuit 1, the coils wound at the positions 1 and 2 on the stator teeth 4 and 5 and B of the power conversion circuit 2 are connected with the B of the power conversion circuit 2, the coils wound at the positions 1 and 2 on the stator teeth 5 and 6 and B of the power conversion circuit 3 are connected with the coil wound at the positions 1 and 2 on the stator teeth 6 and 7 and C of the power conversion circuit 1, the coils wound at the positions 1 and 2 on the stator teeth 7 and 8 and C of the power conversion circuit 2 and 7 are connected with the coil wound at the power conversion circuit 2 C, coils wound at the position 1 on the stator tooth 8 and the position 2 on the stator tooth 9 are connected with the C of the power conversion circuit 3, and the coils wound at the position 1 on the stator tooth 9 and the coils wound at the position 2 on the stator tooth 1 are connected with the A of the power conversion circuit 1. In an optional embodiment, a coil wound at a first position on each stator tooth in the target stator unit and a coil wound at a last position on a stator tooth with the same sequencing position in the same circumferential direction in the subsequent stator unit are connected to the same power conversion circuit, and a coil wound at each remaining position on each stator tooth in the target stator unit and a coil wound at a corresponding previous position on a corresponding stator tooth with the same sequencing position in the same circumferential direction in the subsequent stator unit are connected to the same power conversion circuit, wherein the target stator unit is any one of all stator units sequentially sequenced in the circumferential direction in the wind turbine generator.

In an alternative embodiment, the same stator tooth groups of different stator units have the same winding distribution. In the above example, the second stator unit, the third stator unit, the fourth stator unit, the fifth stator unit, and the sixth stator unit are all the same as the first stator unit, that is, the same stator teeth groups of the 6 stator units have the same winding distribution. In another specific example, a wind power generation system includes a 60 pole 72 slot three phase wind turbine and 4 power conversion circuits, each capable of outputting 3 phase currents. The three-phase current output by each power conversion circuit is represented by A, B, C, a1, B1, and C1 represent phases a, B, and C of the power conversion circuit 1, a2, B2, and C2 represent phases a, B, and C of the power conversion circuit 2, A3, B3, and C3 represent phases a, B, and C of the power conversion circuit 3, and a4, B4, and C4 represent phases a, B, and C of the power conversion circuit 4, respectively. The wind driven generator comprises 6 stator units distributed along the circumference, namely a first stator unit, a second stator unit, a third stator unit, a fourth stator unit, a fifth stator unit and a sixth stator unit.

Fig. 5 is a schematic diagram for illustrating another coil distribution pattern of the first stator unit and the second stator unit. As shown in fig. 5, the first stator unit includes 3 stator tooth groups. Each stator tooth group comprises 4 circumferentially adjacent stator teeth. And 3 coils are wound on each stator tooth by adopting double-layer concentrated windings.

In the embodiment, when the coils wound on the stator teeth except the first coil are connected with the coils wound on the last position of the next stator tooth in series, the coil connection distance is short, the coil span is small, overlapping cannot occur in space, the winding coefficient can be improved, and the wind driven generator has higher torque.

Fig. 6 is a schematic diagram illustrating an integer slot single layer distributed winding. In the example shown in fig. 6, the wind power generation system includes a 4-pole 12-slot three-phase wind power generator and 2 power conversion circuits, each capable of outputting 3-phase current. The three-phase current output by each power conversion circuit is represented by A, B, C, a1, B1 and C1 respectively represent the a phase, B phase and C phase of the power conversion circuit 1, a2, B2 and C2 respectively represent the a phase, B phase and C phase of the power conversion circuit 2, and A3, B3 and C3 respectively represent the a phase, B phase and C phase of the power conversion circuit 3. The wind generator comprises 2 stator units, each stator unit comprising 1 stator tooth group, each stator tooth group comprising 6 circumferentially adjacent stator teeth. And 2 coils in each stator slot are respectively connected with the same one of the 2 power conversion circuits by adopting a single-layer distributed winding. In an alternative embodiment, the same stator tooth groups of different stator units have the same winding distribution. In the above example, the second stator unit is the same as the first stator unit, i.e. the same stator teeth groups of 2 stator units have the same winding distribution.

Under the condition that the coils wound on the same position of the adjacent stator teeth in the stator tooth group are connected with the same coils of different power conversion circuits, if the coils connected with the same coils of the same power conversion circuit are connected in series on all the stator teeth in the stator tooth group, the winding coefficient is lost, and further the torque loss is caused.

In order to solve the above technical problem, in an alternative embodiment, the wind turbine further includes a rotor, the stator teeth in each stator unit correspond to a plurality of permanent magnets on the rotor, wherein the number of stator teeth in each stator unit is less than the number of corresponding permanent magnets, and the pole pitch of the permanent magnets is the same as the slot pitch of the stator slots.

In a specific implementation, the wind driven generator is a permanent magnet synchronous motor.

Fig. 7 is a schematic diagram illustrating a coil distribution manner of the first stator unit. In the example shown in fig. 7, the wind power generation system includes a three-phase wind power generator with 60 poles and 54 slots and 3 power conversion circuits, each capable of outputting 3-phase current. For the first stator unit, 9 stator teeth correspond to 10 permanent magnets, the pole distance of each permanent magnet is tau and is the same as the slot distance of the stator slots, thus a distance of one pole distance is added, the pole distance is divided into two halves of each stator tooth group, and tau/3 slot width is added between adjacent stator tooth groups.

In this embodiment, by adopting the same manner of the slot pitch and the pole pitch, the magnetic flux linkage of the permanent magnet linked with each coil is the largest, and no space waste is caused, and the phase of the back electromotive force generated by each coil connected with the same phase of the same power conversion circuit, such as a1, is almost the same, and similarly, under the condition that the coils are connected in series, the loss of the back electromotive force can be ignored, so that the winding coefficient is improved, and the torque loss is avoided.

Example 2

On the basis of embodiment 1, the present embodiment further provides a wind power generation system, which is different from embodiment 1 in that: the number of coils wound on different stator teeth belonging to the same stator tooth group is different.

In an alternative embodiment, at least two different numbers of coils are wound around stator teeth belonging to the same stator tooth group.

In an alternative embodiment, there are at least two repetitions of the number of coils wound around the stator teeth in one stator unit.

In one specific example, a wind power generation system includes a 48-pole, 54-slot three-phase wind turbine and 4 power conversion circuits, each capable of outputting 3-phase current. The three-phase current output by each power conversion circuit is represented by A, B, C, a1, B1, and C1 represent phases a, B, and C of the power conversion circuit 1, a2, B2, and C2 represent phases a, B, and C of the power conversion circuit 2, A3, B3, and C3 represent phases a, B, and C of the power conversion circuit 3, and a4, B4, and C4 represent phases a, B, and C of the power conversion circuit 4, respectively. The wind driven generator comprises 6 stator units distributed along the circumference, namely a first stator unit, a second stator unit, a third stator unit, a fourth stator unit, a fifth stator unit and a sixth stator unit. Each stator unit comprises 3 circumferentially distributed stator tooth groups, each stator tooth group comprising 3 circumferentially distributed stator teeth.

Fig. 8 is a schematic diagram for illustrating a coil arrangement of a first stator unit.

As shown in fig. 8, the first stator unit includes 3 stator teeth, 2 coils are wound on the

stator teeth

1, 3, 4, 6, 7, and 9, and 3 coils are wound on the

stator teeth

2, 5, and 8. In the first stator unit shown in fig. 8, the number of coils wound on the stator teeth is 2, 3, 2, 3, and 2, and there are three cycles of the number of coils wound on the stator teeth.

In the first stator unit shown in fig. 8, the coil arrangements at

positions

1 and 2 are identical to those at

positions

1 and 2 of fig. 5 in embodiment 1, the coil at position 3 belongs to the power conversion circuit, the coil at position 3 on stator tooth 2 of stator group 1 belongs to phase a4, the coil at position 3 on stator tooth 5 of stator group 2 belongs to phase B4, and the coil at position 3 on stator tooth 8 of stator group 3 belongs to phase C4.

In this embodiment, the number of turns of the coil may be different for coils having different radial positions, and the size and specification of the copper wire may be different. In some scenarios, for example, when the copper wire size reaches the manufacturing upper limit, the corresponding width in the stator slot is only enough to accommodate the copper wires in odd columns, and if the copper wires in even columns are arranged, the size of the copper wires is reduced, and the number of columns is increased, which means that the usage of the insulating material and the occupation ratio in the stator slot are increased. In the embodiment, the coils with different numbers are wound on the adjacent stator teeth of each stator unit, so that the slot filling rate of the stator slots can be improved, and particularly under the condition that the non-parallel slots adopt the coils with different wire diameters. And simultaneously, stronger flexibility is provided for regulating voltage through the number of turns of the coil and series-parallel connection.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.

Claims

1. A wind power generation system, comprising:

the number of phases of each power conversion circuit is the same, and the power conversion circuits are used for converting the frequency of the electric energy output by the wind driven generator;

the coils belonging to the same stator tooth group are at least connected with different phases of different power conversion circuits, and the total number of the coils connected among different phases of the same power conversion circuit is consistent;

the wind driven generator further comprises a rotor, wherein n stator teeth of x stator tooth groups contained in each stator unit correspond to m permanent magnets on the rotor, x, n and m are positive integers, n is less than m, the pole pitch tau of the permanent magnets is the same as the slot pitch of stator slots, and the distances between the stator tooth groups are equal and are (m-n) × tau/x.

2. The wind power system of claim 1, wherein the total number of coils connected to different power conversion circuits is the same or different.

3. The wind power generation system of claim 1, wherein the same number of coils are wound on different stator teeth belonging to the same stator tooth group.

4. The wind power generation system of claim 1, wherein the number of power conversion circuits connected to the coils wound in different stator tooth groups belonging to one stator unit is the same or different.

5. The wind power generation system of claim 1, wherein the number of power conversion circuits connected to coils wound on different stator teeth belonging to the same stator tooth group is the same or different.

6. The wind power generation system of claim 1, wherein the number of coils wound on one stator tooth is less than the number of power conversion circuits.

7. The wind power generation system according to claim 6, wherein the stator teeth are arranged in a sequence in the circumferential direction in a stator tooth group, the coil wound at the second position on each stator tooth and the coil wound at the first position on the following stator tooth are connected to the same one of the same power conversion circuit, and the coil wound at each of the remaining positions on each stator tooth and the coil wound at the corresponding preceding position on the following stator tooth are connected to the same one of the same power conversion circuit.

8. The wind power generation system according to claim 6, wherein the stator teeth are arranged in a sequence in the circumferential direction in a stator tooth group, the coil wound at the first position on each stator tooth and the coil wound at the second position on the following stator tooth are connected to the same one of the same power conversion circuit, and the coil wound at each of the remaining positions on each stator tooth and the coil wound at the corresponding following position on the following stator tooth are connected to the same one of the same power conversion circuit.

9. The wind power generation system of claim 1, wherein the number of coils wound on one stator tooth is the same as the number of power conversion circuits.

10. The wind power generation system according to any one of claims 6 to 9, wherein the coil wound at the first position on each stator tooth in the target stator unit and the coil wound at the last position on the stator tooth with the same sequencing position in the same circumferential direction in the subsequent stator unit are connected to the same power conversion circuit, and the coil wound at each of the other positions on each stator tooth in the target stator unit and the coil wound at the corresponding previous position on the stator tooth with the same sequencing position in the same circumferential direction in the subsequent stator unit are connected to the same power conversion circuit, wherein the target stator unit is any one of all the stator units sequentially sequenced in the circumferential direction in the wind power generator.

11. The wind power generation system of claim 10, wherein if the coils in the stator slots are distributed in a radial sequence, the position closest to the slot tops of the stator slots is the first position, and the position farthest from the slot tops of the stator slots is the last position;

alternatively, the first and second electrodes may be,

if the coils in the stator slots are distributed in sequence along the circumferential direction, the position closest to the stator teeth is the first position, and the position farthest from the stator teeth is the last position.

12. Wind power system according to claim 1, wherein each stator unit comprises the same number of stator tooth groups and/or each stator tooth group comprises the same number of stator teeth.

13. The wind power system of claim 1 wherein the coils in the stator slots are radially or circumferentially spaced one after the other.

14. The wind power generation system of claim 1, wherein the windings of the wind power generator are distributed windings or concentrated windings.