WO2013120230A1

WO2013120230A1 - Double air-gap hybrid excitation direct-drive switch reluctance wind generator and assembly system thereof

Info

Publication number: WO2013120230A1
Application number: PCT/CN2012/000282
Authority: WO
Inventors: 秦明; 肖珊彩
Original assignee: 国电联合动力技术有限公司
Priority date: 2012-02-17
Filing date: 2012-03-06
Publication date: 2013-08-22
Also published as: CN102594062A

Abstract

A double air-gap hybrid excitation direct-drive switch reluctance wind generator and an assembly system thereof. The wind generator comprises a main shaft, a housing, a rotor, an outer stator, and an inner stator. The stators each comprise an iron core, a winding, and a permanent magnet. The rotor uses a doubly salient structure, is arranged between the inner and the outer stators, and is linked to the main shaft. The outer stator and the rotor form a first working air gap, the rotor and the inner stator form a second working air gap, the inner and the outer stators are correspondingly in series-opposing connection to the winding, and the first and the second working air gaps are connected in series through a magnetic circuit. The assembly system comprises a wheel hub, a power converter, a direct current battery, an inverter and a load, a control system, an auxiliary power source, and the wind generator. The main shaft of the wind generator is linked to the wheel hub, and is connected to the power converter. The direct current battery is connected in parallel between the power converter and the inverter and between the power converter and the load. The double air-gap hybrid excitation direct-drive switch reluctance wind generator and the assembly system thereof can greatly reduce the size and weight of the motor, decrease the cost, be conveniently transported, and improve the assembly efficiency.

Description

Double air gap hybrid excitation direct drive switch reluctance wind power generator and its unit system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of wind power, and more particularly to a large double air gap hybrid excitation direct drive switched reluctance wind power generator and its unit system.

Background technique

With the continuous development of the wind power industry, wind power technology is constantly upgrading and replacing. The main performances are: improving single-unit capacity, developing new technologies to improve wind turbine performance, improving wind energy utilization, reducing wind power costs, and paying more attention to wind turbine safety and System reliability control. Wind farm operation control and predictive dispatching technology are also constantly improving. At the same time, the use of offshore wind energy resources, the development of offshore wind farm construction technology, and the development of large offshore wind turbine components are the focus of technological development.

And direct drive full power conversion wind turbines. The doubly-fed wind turbine has the best price/performance ratio, but the ability to cross the grid and support is weak. The transmission chain of the doubly-fed wind turbine must have a high-power gearbox, which puts more stringent requirements on the reliability and maintainability of the unit. Direct-drive full-power conversion wind turbines are connected to the grid through inverters, which have strong ability to traverse the grid faults, have certain power grid support capacity, avoid the maintenance workload of high-power gearboxes, and improve reliability. The rotation speed is very low. With the increase of power, the manufacturing process of the multi-pole direct-drive permanent magnet synchronous generator and the direct-drive electric excitation synchronous generator is complicated, the technical difficulty is large, the motor is large, and the cost is high. With the increasing capacity, the high cost of high-power inverters increases the cost of its use. The switched reluctance type wind power generation system uses a switched reluctance generator as the core of electromechanical energy conversion, and the switched reluctance generator is a double salient pole motor. The stator and the rotor are both convex pole cogging structures, and the stator is provided with concentrated windings. There are neither windings nor permanent magnets on the rotor. This brings the simplicity of the inverter and control and drive. The power characteristics of the wind turbine have its own characteristics. In order to optimize the wind energy capture effect, the switched reluctance generator and the wind turbine must be well matched. By controlling the power generation system, the wind turbine works best. On the power load line, the switched reluctance generator itself has many characteristics of controllable parameters, nonlinearity, and lack of a clear mathematical model. Compared with traditional brushed DC generators and rotary rectified brushless synchronous generators, switched reluctance generators have obvious fault tolerance, easy combination start and power generation, suitable for high temperature (>250 °C) environment operation and large capacity. High efficiency and high power density operation. The air gap magnetic field and the phase flux linkage of the generator continuously and periodically change with the rotor position and the winding phase current, and there is no stable magnetic circuit working point of the conventional motor, but a dynamic three-dimensional magnetic space. The switched reluctance generator does not have independent excitation windings, but is integrated with the centrally embedded stator armature, and realizes excitation and power generation through time-division control of the controller, thereby simplifying the structure and improving reliability. At the same time, the generator phase winding has no electric coupling, and its fault tolerance is greatly enhanced. In addition, the switched reluctance generator has a simple mechanical structure that is robust and reliable. With the improvement of the cost performance of high-power power electronic devices and the development of control strategies, the advantages of switched reluctance wind power generation systems will gradually be reflected. As the motor power increases, the size of the motor will increase. Especially for low-speed motors, such as switched reluctance wind turbines, when the power is greater than megawatts or more, the volume will become quite large, which will cause great difficulty in transportation. At the same time, the stator armature winding current of the traditional switched reluctance motor has the dual functions of excitation and electromagnetic torque. The winding and inverter capacity requirements are large, and the efficiency of the system and the effective utilization of the material are low. It can be seen that the above-mentioned existing switched reluctance wind power generators obviously have inconveniences and defects in structure and use, and need to be further improved. How to create a new large double air gap hybrid excitation direct drive switch reluctance wind power generator and its unit system, which can greatly reduce the volume and weight of the motor, reduce the cost, facilitate transportation and improve the efficiency of the unit. improved aims.

Summary of the invention

The technical problem to be solved by the present invention is to provide a double air gap hybrid excitation direct drive switched reluctance wind power generator, which can greatly reduce the volume and weight, reduce cost and facilitate transportation, thereby overcoming the existing switched reluctance wind power. Insufficient generators.

In order to solve the above technical problem, a double air gap hybrid excitation direct drive switched reluctance wind power generator comprises a main shaft, a casing, a stator and a rotor, and the stator comprises an outer stator and an inner stator, and the outer stator and the inner stator are both The stator core, the stator winding and the permanent magnet are included; the rotor has a double salient pole structure located between the inner and outer stators and is coupled with the main shaft; the outer stator and the rotor form a first working air gap, the rotor and the inner stator A second working air gap is formed, and the stator windings of the outer stator and the inner stator are reversely connected in series with the same direction winding, and the first working air gap is connected in series with the second working air gap magnetic circuit. As an improvement of the present invention, a slot insulating layer is further disposed between the stator core and the stator winding of the outer stator and the inner stator, and an inter-coil insulating layer is disposed in the stator winding, and the stator winding and the permanent magnet are Magnetic wedges are provided between them. The utility model further comprises a rotor turntable, a hollow short shaft, a bearing and a centering mechanism, wherein: the front end of the rotor is fixedly connected with the rotor turntable, the rear end is rotatably connected with the outer casing by a centering mechanism; the hollow short shaft is connected with the main shaft, and the inner ring of the bearing is set at The hollow short shaft is pressed by the rotor turntable. The bearing is a double row roller bearing. The centering mechanism comprises a centering bearing and a bearing end cover, a front bushing and a rear bushing for fixing the centering bearing position, wherein: the bearing end cap is fixedly connected with the rear end of the rotor through the rear end support of the rotor, the front bushing And the rear sleeve is fixedly connected to the outer casing through the rear flange of the generator. The bearing end cover and the front and rear bushings are further provided with a bearing sealing ring, a bearing sealing plate and a bearing sealing ring spacer. The outer stator is mounted on the inner wall of the outer casing, and the inner stator is mounted inside the outer casing through the bracket and the rear flange of the generator. The invention also provides a unit system of a double air gap hybrid excitation direct drive switched reluctance wind power generator, which can greatly improve the unit efficiency, thereby overcoming the shortcomings of the existing switched reluctance wind power generator unit system. In order to solve the above technical problems, the present invention relates to a wind turbine system, including a hub, a power converter, a DC battery, an inverter and a load, a control system, an auxiliary power source, and the above-described double air gap hybrid excitation direct drive switch reluctance wind power Generator, wherein: the main shaft of the double air gap hybrid excitation switch reluctance wind power generator is linked with the hub and connected with the power converter; a DC battery is connected in parallel between the power converter and the inverter and the load; DC battery, power conversion And the auxiliary power supply are respectively connected to the control system. As a further improvement, the control system includes a driving circuit, an overvoltage and overcurrent protection circuit, a voltage current detecting circuit, a rotor position detecting circuit, a single chip microcomputer or a DSP minimum system circuit. After adopting such a design, the invention adopts a double air gap structure in the direct drive switched reluctance wind power generator and its unit system, and adopts the method of electric excitation and permanent magnet mixed excitation in the excitation mode, and in the transmission chain at the same time. The technical solution of single bearing support is adopted, so it has the following advantages:

1. Simplified the transmission system of the wind turbine, eliminating the need for high-power mechanical gearboxes. Since the wind turbines consisting of the high-power gearbox eliminates the need for complex oil handling systems;

2. The direct drive double air gap switch reluctance generator is compared with the single air gap switch reluctance generator. The output power per unit volume of the motor is increased, thereby reducing the volume and weight of the motor, which reduces the cost and facilitates transportation;

3, direct drive double air gap hybrid excitation switch reluctance generator relative to direct drive double air gap electric excitation switch reluctance generator, Han air gap electric excitation switch reluctance generator inner and outer stator armature current simultaneously undertake excitation And the dual role of generating electromagnetic torque, the winding and inverter capacity requirements are large, the system efficiency and material utilization are low; and the direct drive double air gap hybrid excitation switched reluctance generator, which retains The characteristics of the switched reluctance generator are applied to the high-performance rare earth permanent magnet material in the generator, so that the air gap flux density of the generator is jointly generated by the armature current and the permanent magnet, so that the electromagnetic torque is large. The advantages of less copper, low copper consumption of P, high material utilization, and high efficiency of the unit;

4. The transmission mode of the direct drive wind turbine of the present invention uses a single bearing support mode to make the hollow main shaft shorter, which greatly simplifies the transmission structure and greatly reduces the length and weight of the whole machine;

5. The direct drive wind turbine of the present invention adopts a single bearing support structure to reduce the length of the whole machine while reducing the distance from the center of the wind wheel to the center of the tower, thereby reducing the tilting moment and yaw drive of the yaw bearing. Power

6. The double air gap hybrid excitation direct drive switched reluctance generator rotor end of the invention adopts a centering bearing structure to ensure the concentricity of the stator and the rotor at any time. As described above, the air gap flux density of the motor of the present invention is jointly generated by the inner and outer stator armature currents and the permanent magnets mounted on the inner and outer stator magnetic wedges, due to the simple and reliable double air gap hybrid excitation. Switched reluctance generators greatly reduce the weight and cost of direct-drive switched reluctance wind turbines of MW and above, improve the efficiency of the unit system and the effective utilization of materials, and greatly improve the switching reluctance wind turbines. The competitive advantage of the wind power industry can widely replace the direct drive type permanent magnet wind power generation system, the direct drive type electric excitation wind power generation system, and the direct drive type switched reluctance wind power generation system, which have broad market prospects.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing is a summary of the embodiments of the present invention. 1 is a schematic structural view of a double air gap hybrid excitation direct drive switched reluctance wind power generator according to the present invention. 2 is a schematic cross-sectional view of a stator and a rotor of a direct drive switched reluctance wind power generator of the present invention. Fig. 3 is a partially enlarged schematic view showing a portion A in Fig. 2; Figure 4 is a partially enlarged schematic view of the portion B of Figure 2; Fig. 5 is a partially enlarged schematic view showing a portion C in Fig. 1. 6 is a schematic view showing the structure of a double air gap hybrid excitation direct drive switched reluctance wind power generator system according to the present invention. Detailed ways

Referring to FIG. 1 , some short center lines indicate bolts and nuts of various specifications. The double air gap hybrid excitation direct drive switch reluctance wind power generator of the present invention adopts a single rotor double stator structure, mainly including a main shaft 1. The outer casing 2, the rotor 3, the outer stator 4 and the inner stator 5. Referring to FIG. 2, the rotor 3 is mounted between the outer stator 4 and the inner stator 5 and is coupled with the main shaft 1 by a double salient pole structure as shown. Specifically, the outer stator 4 is mounted on the inner wall of the outer casing 2, as shown in FIG. 3, the outer stator 4 mainly includes an outer stator core 41, an outer stator winding 42 and an outer permanent magnet 43, and is located at the outer stator core. An outer stator slot insulating layer 44 between the outer stator winding 42 and an outer stator coil insulating layer 45 located in the outer stator winding 42 and an outer stator magnetic slot wedge 46 between the outer stator winding 42 and the outer permanent magnet 43. The inner stator 5 is mounted inside the outer casing 2 through the bracket 7 and the generator rear flange 22. Referring to FIG. 4, the inner stator 5 mainly includes an inner stator core 51, an inner stator winding 52 and an inner permanent magnet 53, and An inner stator slot insulating layer 54 between the inner stator core 51 and the inner stator winding 52, an inner stator inter-coil insulating layer 55 located in the inner stator winding 52, and an inner stator between the inner stator winding 52 and the inner permanent magnet 53 Magnetic slot wedge 56. The present invention is different from the conventional switched reluctance generator structure in that a double air gap structure is adopted, the outer stator 4 and the rotor 3 form a first working air gap, the rotor 3 and the inner stator 5 form a second working air gap, and the outer stator winding 42 and the inner stator The sub-windings 52 are connected in reverse series with the same-direction windings, and the first working air gap is connected in series with the second working air-gap magnetic circuit. In addition, the inner and outer stator slots of the present invention are respectively installed with inner and outer The number of stator slots is the same number of permanent magnets. Compared with the conventional switched reluctance motor, the present invention is equivalent to a permanent magnet magnetic source connected in parallel to the inner and outer stator excitations, and after the hybrid excitation structure is used, in the excitation working phase of the generator. The excitation flux required by the generator is the sum of the magnetic flux generated by the excitation current of the inner and outer stator windings and the output magnetic flux when the inner and outer permanent magnets act alone. In the case of the same output power, the motor efficiency is greatly improved.

Preferably, the front end of the rotor 3 is mounted inside the casing 2 through the rotor turntable 31, the hollow stub shaft 32, the bearing 33, and the centering mechanism 6, and is interlocked with the main shaft 1. The front end of the rotor 3 is provided with a rotor front end platen 35, and the rotor 3 and the rotor front end platen 35 are fastened in the groove of the rotor turntable 31 by the rotor tensioning long bolts. The bearing 33 is preferably a double row roller bearing, the inner ring is sleeved on the hollow short shaft 32, and is pressed by the rotor turntable 31 through the rotor turntable fastening bolt, and the front end of the hollow short shaft 32 is guided by the flange and the main shaft. 1 connected. The outer ring of the bearing 33 is mounted in the bearing housing of the generator front flange 21 and is fastened by bearing fastening bolts. Referring to FIG. 5, the centering mechanism 6 includes a centering bearing 61 and a bearing end cover 62, a front bushing 63 and a rear bushing 64 that fix the centering bearing 61. The bearing end cap 62 passes through the rotor rear end support. 34 is fixedly connected to the rotor 3 and its rotor rear end plate 36, and the front bushing 63 and the rear bushing 64 are fixedly connected to the generator rear flange 22, and are disposed at the bearing end cap 61 and the front and rear bushings 63, 64. A bearing seal 65, a bearing seal plate 66, and a bearing seal jaw spacer 67 are disposed therebetween to seal the centering bearing 61 and to achieve relative rotational connection of the rotor 3, the centering mechanism 6, and the outer casing 2. Specifically, the centering bearing 61 is disposed between the outer ring of the extended end of the generator flange 1 and the inner ring of the rotor rear end support 34, and the front bushing 63 and the rear bushing 64 are placed on the rear flange of the generator. 22 The outer ring of the projecting end is mounted with the centering bearing 61 between the front and rear bushings 63, 64. The bearing end cover 62 is placed outside the centering bearing 61, and is fixed to the rotor rear end support member 34 via a fastening bolt. The extended end of the generator rear flange 22 is fixed together with the inner stator bracket 7 via a fastening bolt to generate electricity. The outer circumference of the front flange 21 of the machine is fastened to the front end of the generator casing 2 by the front flange fastening bolt of the generator, and the rear end of the generator casing 2 is connected to the flange of the generator and the rear flange of the generator 22 Machine The frame 8 is fastened together. Since the generator rear flange 22 simultaneously connects the centering mechanism 6 and the inner stator bracket 7, it is ensured that the rotor 3 can be concentric with the outer stator 4 and the inner stator 5 even after some deformation of the rotor 3. Please refer to FIG. 6 , the wind turbine system of the present invention includes a hub, a power converter, a DC battery, an inverter and a load, a control system, an auxiliary power source, and a double air gap hybrid excitation direct drive switch magnetoresistance of the present invention. Wind Turbines. Among them, the salient pole rotor of the wind power generator is rotated by the hub through the main shaft, which is a wind energy/mechanical energy conversion device. At the same time, the wind power generator is connected with the power converter, and a DC battery is connected in parallel between the power converter and the inverter and the load, and the DC battery, the power converter and the auxiliary power source are respectively connected with the control system. The power converter receives the control command issued by the control system, and outputs the direct current generated by the wind power generator to the energy storage device of the system to continuously flow the battery, and the inverter and the load invert the direct current generated by the wind power generator into alternating current and directly supply the battery. For the AC load, the auxiliary power supply 25 provides a multi-channel power supply of ±15V, ±5V for the control system 24. Preferably, the control system of the present invention comprises a driving circuit, an overvoltage and overcurrent protection circuit, a voltage and current detecting circuit, a rotor position detecting circuit, a single chip microcomputer or a DSP minimum system circuit, etc., and the function of the control system is to comprehensively process the rotor position detector. The feedback information of the motor rotor position, speed and current provided by the voltage and current detector and the external input command realize the control of the operating state of the double air gap hybrid excitation switch reluctance generator, and control the internal and external stator phase windings to work in turn. , to achieve the conversion of mechanical energy to electrical energy. It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art The technical solutions described in the foregoing embodiments may be modified, or some of the technical features may be equivalently replaced. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A double air gap hybrid excitation direct drive switched reluctance wind power generator comprising a main shaft, a casing, a stator and a rotor, wherein: the stator comprises an outer stator and an inner stator, and the outer stator and the inner stator each comprise a stator The iron core, the stator winding and the permanent magnet; the rotor adopts a double salient pole structure, located between the inner and outer stators, and is linked with the main shaft; the outer stator and the rotor form a first working air gap, and the rotor and the inner stator form a second The working air gap, the stator windings of the outer stator and the inner stator are oppositely connected in series with the same direction winding, and the first working air gap is connected in series with the second working air gap magnetic circuit.

2. The double air gap hybrid excitation direct drive switched reluctance wind power generator according to claim 1, wherein the edge layer has an inter-coil insulation layer in the stator winding, and a magnetic wedge is disposed between the stator winding and the permanent magnet.

3. The dual air gap hybrid excitation direct drive switched reluctance wind power generator according to claim 1, further comprising a rotor turntable, a hollow stub shaft, a bearing and a centering mechanism, wherein: the rotor front end is fixedly connected to the rotor turntable The rear end is rotatably connected to the outer casing by a centering mechanism; the hollow short shaft is connected with the main shaft, and the inner ring of the bearing is set on the hollow short shaft, and is pressed by the rotor turntable. '

4. The Han air gap hybrid excitation direct drive switched reluctance wind power generator according to claim 3, wherein the bearing adopts a double row roller bearing.

5. The dual air gap hybrid excitation direct drive switched reluctance wind power generator according to claim 3, wherein said centering mechanism comprises a centering bearing and a bearing end cover and a front bushing for fixing the centering bearing position. And the rear bushing, where: The bearing end cover is fixedly connected to the rear end of the rotor through the rear end support of the rotor, and the front bushing and the rear bushing are fixedly connected to the outer casing through the rear flange of the generator.

6. The double air gap hybrid excitation direct drive switched reluctance wind power generator according to claim 5, wherein the bearing end cover and the front and rear bushings are further provided with a bearing sealing ring and a bearing sealing plate. And bearing seal spacers.

7. The dual air gap hybrid excitation direct drive switched reluctance wind power generator according to claim 1, wherein said outer stator is mounted on an inner wall of the outer casing, and the inner stator is mounted on the outer casing through the bracket and the rear flange of the generator. internal.

8. A wind turbine system, characterized by comprising a hub, a power converter, a DC battery, an inverter and a load, a control system, an auxiliary power source, and the dual air gap mixing according to any one of claims 1-7. Excitation direct drive switched reluctance wind power generator, wherein: double air gap hybrid excitation switch reluctance wind power generator 'spindle and hub linkage, and connected with power converter; power converter and inverter and load are connected in parallel DC battery; DC battery, power converter and auxiliary power supply are respectively connected to the control system.

The wind power generator system according to claim 8, wherein said control system comprises a drive circuit, an overvoltage and overcurrent protection circuit, a voltage and current detection circuit, a rotor position detection circuit, a single chip microcomputer or a DSP minimum system circuit.