CN108365718A - A kind of birotor permanent magnetic doubly-fed wind turbine and electricity generation system - Google Patents

Abstract

A kind of birotor permanent magnetic doubly-fed wind turbine of present invention offer and electricity generation system, permanent magnet outer rotor paste magnet structure using permeability magnetic material surfaces externally and internally, and surfaces externally and internally permanent magnetism body position corresponds.The magnet structure can improve the air gap flux density of motor gas-gap.The torque density of motor is directly proportional to motor gas-gap surface area, air gap flux density value, the birotor permanent magnetic doubly-fed wind turbine of the present invention, increase air gap surface product, and increased outer rotor magnet all increases air gap flux density using special magnet structure, to improve the torque density of motor.The inner and outer rotors structure that birotor permanent magnetic doubly-fed wind turbine uses, it not only improves inner and outer Rotator air gap flux density, inner and outer rotors is made to grip portion's flux density reduction, to improve the operational efficiency and torque density of motor, and inner and outer rotors air gap flux density is made to be in Sine distribution, it can ensure that winding potential is in Sine distribution.

Description

A double-rotor permanent magnet double-fed wind generator and power generation system

technical field

The invention relates to the technical field of new energy power generation, in particular to a double-rotor permanent magnet double-fed wind power generator and a power generation system.

Background technique

Clean wind energy is one of the most dynamic renewable energy sources. Facing the dual pressure of energy crisis and deterioration of the earth's environment, the development and utilization of wind energy has attracted global attention. Traditional wind generators usually use permanent magnet synchronous generators or ordinary induction generators, but the above two generators cannot achieve variable speed and constant frequency operation, and the conversion efficiency of wind energy is low. In recent years, doubly-fed generators capable of variable-speed constant-frequency and high-efficiency power generation have become a research hotspot in wind power generation. However, ordinary doubly-fed wind turbines also have prominent problems, such as weak low-voltage ride-through capability and large excitation capacity.

In order to further improve the operating performance of DFIG, the research on DFIG at home and abroad mainly focuses on two aspects, one is to study the grid-connected operation control strategy of DFIG to improve the grid-connected stability, and the other One aspect is to study the structure of the doubly-fed generator body to increase the power density of the generator. With the continuous improvement of the performance of rare earth permanent magnet materials, the research of using permanent magnets in the design of motors to improve the performance of motors continues to emerge. At present, permanent magnet motors used in wind power generation still have disadvantages such as complex power converters in power generation systems and high control costs. .

Contents of the invention

In view of the above-mentioned deficiencies in the existing wind power generator technology, the present invention provides a double-rotor permanent magnet double-fed wind power generator with a double-rotor permanent magnet structure, adopting back-to-back converters, and suitable for direct drive or semi-direct drive applications. Compared with traditional permanent magnet synchronous wind turbines, it has smaller volume and weight with the same capacity, lower cost, and can better utilize wind energy at low wind speeds. Compared with traditional doubly-fed generators, the excitation capacity will be reduced.

To achieve the above object, the present invention provides a double-rotor permanent magnet doubly-fed wind generator, comprising: a casing, the casing is provided with a first side and a second side; the first side is provided with a first fixing hole, and the second side A second fixing hole is provided; the first bearing is set inside the hole wall of the first fixing hole, and the stator bearing is set inside the hole wall of the second fixing hole;

There is a winding inner rotor inside the casing, the outer winding inner rotor is wrapped with a permanent magnet outer rotor, and the outer permanent magnet outer rotor is wrapped with a stator;

The stator is fixed on the inner wall of the casing;

The permanent magnet outer rotor is provided with a first cylindrical frame and a second cylindrical frame;

The first circumferential surface of the first cylindrical frame is connected with the second circumferential surface of the second cylindrical frame; the column frame of the first cylindrical frame is provided with a permanent magnet;

A third bearing is provided on the second circumferential surface of the first cylindrical frame; the position of the second circumferential surface of the first cylindrical frame is set close to the second side;

The first circumferential surface of the second cylindrical frame extends to the first side of the casing; the second cylindrical frame is provided with a second cylindrical frame matching portion matched with the first bearing, and the first bearing is sleeved on the second cylindrical The outside of the matching part of the body frame and the inner side of the matching part of the second cylindrical body frame are provided with a third bearing, and the matching part of the second cylindrical body frame is free to rotate between the first bearing and the third bearing;

The winding inner rotor is provided with a three-phase rotor winding, and the center of the winding inner rotor is provided with a rotating shaft; the first end of the rotating shaft is in interference fit with the inner wall of the third bearing, and the first end of the rotating shaft rotates freely with the third bearing; the second end of the rotating shaft passes through the Through the inner hole of the third bearing and the inner hole of the stator bearing, it extends to the outside of the second side, and the second end of the rotating shaft rotates freely on one side of the second side.

Preferably, the centerline of the stator, the centerlines of the first cylindrical frame and the second cylindrical frame of the permanent magnet outer rotor, and the centerline of the winding inner rotor are on the same straight line.

Preferably, the second end of the rotating shaft is provided with an inner runner bushing, and a wind wheel is sheathed on the inner runner bushing.

Preferably, the three-phase rotor windings are sequentially connected with brushes and slip rings, and the three-phase rotor windings are sequentially connected to the rotor double-side PWM converter through the brushes and slip rings, and the three-phase excitation power is provided by the rotor double-side PWM converter;

The stator includes: a stator core and a stator three-phase winding; the stator three-phase winding and the three-phase rotor winding are three-phase symmetrical AC windings.

Preferably, an air gap is provided between the permanent magnet and the stator, and the flux linkage generated by the permanent magnet and the flux linkage generated by the three-phase rotor winding connected to the AC excitation power supply in the air gap are simultaneously connected with the flux linkage generated by the three-phase winding of the stator. The magnetic field turn chain realizes the mixed excitation.

Preferably, the number of poles of the permanent magnet outer rotor is the same as that of the stator and the winding inner rotor;

The permanent magnet outer rotor is made of magnetically conductive material, the positions of the permanent magnets correspond to the positions of the three-phase rotor windings, and the magnetization direction of the permanent magnets is radial magnetization.

Preferably, the cylinder diameter of the first cylinder frame is larger than the cylinder diameter of the second cylinder frame.

A power generation system based on double-rotor permanent magnet double-fed wind turbine, including: stator main inductance L _s , stator resistance R _s , stator winding back electromotive force jω _s ψ _s , transformer L _m , winding inner rotor resistance R _r , the winding inductance of the inner rotor L _r , the back electromotive force of the winding inner rotor jω _s1 ψ _r ;

The wind wheel transmits the wind energy captured by the wind to the wound inner rotor, and the three-phase winding of the wound inner rotor rotates at a certain speed driven by the excitation voltage u _r on the rotor side and the wind wheel, and induces a three-phase voltage u _s on the stator , the flux linkage generated by the permanent magnet and the flux linkage generated by the three-phase rotor winding connected to the AC excitation power supply in the air gap, and at the same time linked with the magnetic field turn linkage generated by the stator three-phase winding, to achieve mixed excitation, in the stator main inductance Ls When it is larger than the stator resistance Rs, a larger magnetizing current _im will be generated; the permanent magnet installed on the outer rotor of the permanent magnet will generate an electromotive force u _P to reduce the magnetizing current _im required for operation;

Stator induced three-phase voltage u _s , rotor side excitation voltage _ur , stator induced current is _s , rotor side excitation current _ir are stator and winding internal rotor voltage and current vectors respectively; ψ _s , ψ _r are stator and winding inner rotor voltage and current vectors respectively; In-line rotor flux vector, vector form F=Fd+jFq;

ω _s and ω _s1 are grid synchronous angular frequency and motor slip angular frequency respectively; stator resistance R _s , stator main inductance L _s , winding inner rotor resistance R _r , winding inner rotor inductance L _r , transformer L _m , are the winding resistance, inductance and mutual inductance attributed to the stator and inner wound rotor respectively;

Stator winding back electromotive force jω _s ψ _s winding inner rotor back electromotive force jω _s1 ψ _r is the counter electromotive force produced by stator and inner winding rotor winding respectively.

As can be seen from the above technical solutions, the present invention has the following advantages:

The permanent magnet outer rotor adopts the permanent magnet structure pasted on the inner and outer surfaces of the magnetic conductive material, and the positions of the permanent magnets on the inner and outer surfaces correspond to each other. The magnet structure can improve the air gap magnetic density of the motor air gap.

The torque density of the motor is proportional to the surface area of the air gap of the motor and the magnetic density value of the air gap. The double-rotor permanent magnet double-fed wind power generator of the present invention increases the surface area of the air gap, and the increased outer rotor magnets all use special magnets The structure increases the air gap magnetic density, thereby improving the torque density of the motor.

The inner and outer rotor structure adopted by the double-rotor permanent magnet double-fed wind power generator of the present invention not only increases the air-gap magnetic density of the inner and outer rotors, but also reduces the magnetic density of the yoke of the inner and outer rotors, thereby improving the operating efficiency and torque density of the motor. Moreover, the air gap magnetic density of the inner and outer rotors is sinusoidally distributed, which can ensure that the winding potential is sinusoidally distributed.

The double-rotor permanent magnet double-fed wind turbine adopts permanent magnet magnetic field excitation, which can flexibly adjust the air gap magnetic field, reduces the excitation capacity of the rotor-side inverter, and improves the power factor and efficiency of the motor. The existence of the permanent magnetic field improves the operation ability of the motor under various fault states, and provides strong support for the stability of the power grid under fault states.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the accompanying drawings that need to be used in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. As far as people are concerned, other drawings can also be obtained based on these drawings on the premise of not paying creative work.

Figure 1 is an overall schematic diagram of a double-rotor permanent magnet doubly-fed wind turbine;

Fig. 2 is a schematic diagram of the axial section structure of the double-rotor permanent magnet doubly-fed wind generator;

Fig. 3 is an overall schematic diagram of a power generation system using a double-rotor permanent magnet doubly-fed wind generator.

Detailed ways

In order to make the purpose, features and advantages of the present invention more obvious and understandable, the technical solutions protected by the present invention will be clearly and completely described below using specific embodiments and accompanying drawings. Obviously, the implementation described below Examples are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in this patent, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this patent.

This embodiment provides a double-rotor permanent magnet double-fed wind power generator, as shown in Figure 1 and Figure 2, comprising: a casing 12, the casing 12 is provided with a first side 21 and a second side 22; the first side 21 A first fixing hole is provided, and a second fixing hole is provided on the second side; the hole wall of the first fixing hole is provided with a first bearing 10, and the hole wall of the second fixing hole is provided with a stator bearing 8;

The casing 12 is provided with a wire-wound inner rotor 5, and the wire-wound inner rotor 5 is wrapped with a permanent magnet outer rotor 3, and the permanent magnet outer rotor 3 is wrapped with a stator 1; the stator 1 is fixed on the inner wall of the casing 12; the stator 1 The way of fixing on the inner wall of the casing 12 is not limited here, and bolt connection, rivet connection and the like can be used.

The permanent magnet outer rotor 3 is provided with a first cylindrical frame 23 and a second cylindrical frame 24 ; preferably, the cylindrical diameter of the first cylindrical frame 23 is larger than the cylindrical diameter of the second cylindrical frame 24 . This can reduce the area of the permanent magnet outer rotor 3, save materials, and can also increase a permanent magnet outer rotor concentrically arranged with the wound rotor on the AC and permanent magnet hybrid excitation doubly-fed wind power generator. The permanent magnet 4 of the first cylindrical frame 23 can provide strong excitation for the stator air gap, thereby improving the power factor and power density of the generator. The cylinder diameter of the first cylindrical frame 23 is larger than that of the second cylindrical frame 24, which can concentrate the strong excitation to the first cylindrical frame 23, thereby improving the power factor and power density of the generator.

The third bearing 25 is provided on the second circumferential surface of the first cylindrical frame 23; the position of the second circumferential surface of the first cylindrical frame 23 is set close to the second side 22;

The first circumferential surface of the second cylindrical frame 24 extends to the first side 21 of the casing 12; the second cylindrical frame 24 is provided with a second cylindrical frame matching portion 26 that matches the first bearing 10, and the first bearing 10 is set on the outside of the second cylindrical frame matching part 26, and the inner side of the second cylindrical frame matching part 26 is sleeved with a third bearing 27, and the second cylindrical frame matching part 26 is connected between the first bearing 10 and the third bearing Free rotation between 27;

The wound inner rotor 5 is provided with a three-phase rotor winding 6, and the center of the wound inner rotor is provided with a rotating shaft 7; the first end of the rotating shaft 7 is in interference fit with the inner wall of the third bearing 27, and the first end of the rotating shaft 7 and the third bearing 27 rotate freely The second end of the rotating shaft 7 passes through the inner hole of the third bearing 25 and the inner hole of the stator bearing 8 in turn, and extends to the outside of the second side 22, and the second end of the rotating shaft 7 rotates freely on the second side 22 side.

Wherein, the centerline of the stator 1, the centerlines of the first cylindrical frame 23 and the second cylindrical frame 24 of the permanent magnet outer rotor 3, and the centerline of the winding inner rotor 5 are on the same straight line. The permanent magnet outer rotor 3 is installed between the stator 1 and the winding inner rotor 5, and the permanent magnet outer rotor 3 can freely rotate around the bearing. The permanent magnet 4 is fixed together with the permanent magnet outer rotor 3 . It can only rotate in the same direction as the winding inner rotor 5 .

In this embodiment, the second end of the rotating shaft 7 is provided with an inner runner sleeve, and a wind wheel 14 is sleeved on the inner runner sleeve.

In this embodiment, the three-phase rotor winding 6 is sequentially connected with brushes 9 and slip rings 11, and the three-phase rotor winding 6 is connected to the rotor double-side PWM converter through the brush 9 and slip ring 11 in turn, and the rotor double-side PWM converter A three-phase excitation power supply is provided; the stator 1 includes: a stator core and a stator three-phase winding 5; the stator three-phase winding 5 and the three-phase rotor winding 6 are three-phase symmetrical AC windings.

In this embodiment, an air gap is provided between the permanent magnet 4 and the stator 1, and the flux linkage produced by the permanent magnet 4 and the flux linkage turn linkage produced by the three-phase rotor winding 6 of the AC excitation power supply in the air gap are simultaneously connected with the The magnetic field turn chain generated by the stator three-phase winding 5 realizes mixed excitation.

The number of poles of the permanent magnet outer rotor will be the same as that of the stator and the winding inner rotor; the permanent magnet outer rotor 3 is made of magnetically conductive material, and the position of the permanent magnet 4 corresponds to the position of the three-phase rotor winding 6, The magnetization of the permanent magnet 4 is radial magnetization. The magnet structure can improve the air gap magnetic density of the double air gap of the motor.

There is an inner air gap between the motor winding inner rotor and the stator, and an outer air gap between the permanent magnet outer rotor 3 and the stator. The inner and outer air gaps of the motor are respectively formed between the inner and outer rotors and the stator, and the formation of double air gaps increases the effective air gap area of the motor. The stator core and rotor core are composed of silicon steel laminations or other magnetically permeable materials, which are the same as the manufacturing process of ordinary motors.

In this embodiment, the capacity of the excitation converter and the impact stress during operation are reduced by changing the body structure of the dual-rotor permanent magnet double-fed wind power generator, which not only helps to reduce the weight of the wind power generation system, but also helps to save wind power. Power generation operation and maintenance costs.

The double-rotor permanent magnet doubly-fed wind generator can reduce the mechanical impact of the wind turbine when it starts and runs at variable speed, and at the same time reduces the excitation capacity of the rotor-side converter. Moreover, in view of the shortcomings of the existing wind power generator technology, such as large impact at start-up and large capacity of the excitation converter on the rotor side of the megawatt-class capacity fan, the present invention adopts a back-to-back converter and is suitable for direct drive or semi-direct drive occasions. Compared with the traditional doubly-fed wind turbine, the fed wind generator has smaller volume and weight under the same capacity, lower maintenance cost, smaller excitation capacity, and better utilization of wind energy at low wind speeds.

The permanent magnet outer rotor is not connected to any load. The number of poles of the permanent magnet outer rotor should be the same as that of the stator and the wound inner rotor; the wound inner rotor is installed inside the permanent magnet outer rotor, and there is an air gap between the permanent magnet outer rotor and the wound inner rotor includes the inner rotor Iron core and winding; the inner rotor is fixedly connected with the rotating shaft. Both the stator winding and the wound inner rotor are three-phase symmetrical AC windings.

The first cylindrical frame 23 and the second cylindrical frame 24 of the permanent magnet outer rotor are made of magnetically permeable materials. The inner and outer surfaces of the first cylindrical frame 23 are pasted with permanent magnet structures, and the positions of the permanent magnets on the inner and outer surfaces correspond to each other. The magnet structure can improve the air gap magnetic density of the double air gap of the motor.

The torque density of the motor is directly proportional to the surface area of the air gap of the motor and the magnetic density value of the air gap. The AC and permanent magnet hybrid excitation double-fed wind power generator of the present invention increases the surface area of the air gap, and the increased permanent magnet external rotor magnets are all The special magnet structure increases the air gap magnetic density, thereby improving the torque density of the motor.

The inner and outer rotor structure adopted by the AC and permanent magnet hybrid excitation double-fed wind power generator in this embodiment not only increases the air gap magnetic density of the inner and outer rotors, but also reduces the magnetic density of the yoke of the inner and outer rotors, thereby improving the operating efficiency and rotation speed of the motor. Moment density, and the inner and outer rotor air gap magnetic density is sinusoidal distribution, which can ensure the winding potential is sinusoidal distribution.

The present invention also provides a power generation system based on double-rotor permanent magnet double-fed wind power generator, as shown in Figure 3, including: stator main inductance L _s , stator resistance R _s , stator winding back electromotive force jω _s ψ _s , transformer L _m , the winding inner rotor resistance R _r , the winding inner rotor inductance L _r , the winding inner rotor counter electromotive force jω _s1 ψ _r ;

The wind wheel transmits the wind energy captured by the wind to the wound inner rotor, and the three-phase winding of the wound inner rotor rotates at a certain speed driven by the excitation voltage u _r on the rotor side and the wind wheel, and induces a three-phase voltage u _s on the stator , the flux linkage generated by the permanent magnet and the flux linkage generated by the three-phase rotor winding connected to the AC excitation power supply in the air gap, and at the same time linked with the magnetic field turn linkage generated by the stator three-phase winding, to achieve mixed excitation, in the stator main inductance Ls When it is larger than the stator resistance Rs, a larger magnetizing current _im will be generated; the permanent magnet installed on the outer rotor of the permanent magnet will generate an electromotive force u _P to reduce the magnetizing current _im required for operation;

Stator induced three-phase voltage u _s , rotor side excitation voltage _ur , stator induced current is _s , rotor side excitation current _ir are stator and winding internal rotor voltage and current vectors respectively; ψ _s , ψ _r are stator and winding inner rotor voltage and current vectors respectively; In-line rotor flux vector, vector form F=F _d +jF _q ;

ω _s and ω _s1 are grid synchronous angular frequency and motor slip angular frequency respectively; stator resistance R _s , stator main inductance L _s , winding inner rotor resistance R _r , winding inner rotor inductance L _r , transformer L _m , are the winding resistance, inductance and mutual inductance attributed to the stator and inner wound rotor respectively;

Stator winding back electromotive force jω _s ψ _s winding inner rotor back electromotive force jω _s1 ψ _r is the counter electromotive force produced by stator and inner winding rotor winding respectively.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A double-rotor permanent magnet doubly-fed wind-driven generator, is characterized in that, comprises: casing (12), and casing (12) is provided with first side (21) and second side (22); First side (21) There is a first fixing hole, and the second side is provided with a second fixing hole; the first bearing (10) is set in the hole wall of the first fixing hole, and the stator is set in the hole wall of the second fixing hole bearing (8); The casing (12) is provided with a wire-wound inner rotor (5), the wire-wound inner rotor (5) is wrapped with a permanent magnet outer rotor (3), and the permanent magnet outer rotor (3) is wrapped with a stator (1); The stator (1) is fixed on the inner wall of the casing (12); The permanent magnet outer rotor (3) is provided with a first cylindrical frame (23) and a second cylindrical frame (24); The first circumferential surface of the first cylindrical frame (23) is connected with the second circumferential surface of the second cylindrical frame (24); permanent magnets (4) are provided on the cylindrical frame of the first cylindrical frame (23); The third bearing (25) is provided on the second circumferential surface of the first cylindrical frame (23); the position of the second circumferential surface of the first cylindrical frame (23) is set close to the second side (22); The first circumferential surface of the second cylindrical frame (24) extends to the first side (21) of the casing (12); the second cylindrical frame (24) is provided with the second The cylindrical frame matching portion (26), the first bearing (10) is sleeved on the outside of the second cylindrical frame matching portion (26), and the inner side of the second cylindrical frame matching portion (26) is sleeved with a third bearing ( 27), the second cylinder frame matching portion (26) freely rotates between the first bearing (10) and the third bearing (27); The wound inner rotor (5) is provided with a three-phase rotor winding (6), and the center of the wound inner rotor is provided with a rotating shaft (7); the first end of the rotating shaft (7) is in interference fit with the inner wall of the third bearing (27), and the rotating shaft ( 7) The first end and the third bearing (27) rotate freely; the second end of the rotating shaft (7) passes through the inner hole of the third bearing (25) and the inner hole of the stator bearing (8) in sequence, and extends to the second side (22) Externally, the second end of the rotating shaft (7) is free to rotate on the side of the second side (22). 2. The double-rotor permanent magnet double-fed wind power generator according to claim 1, characterized in that, The center line of the stator (1), the center line of the first cylindrical frame (23) and the center line of the second cylindrical frame (24) of the permanent magnet outer rotor (3) and the center line of the inner rotor (5) of the winding are at the same on a straight line. 3. The double-rotor permanent magnet double-fed wind power generator according to claim 1 or 2, characterized in that, The second end of the rotating shaft (7) is provided with an inner runner sleeve, and the inner runner sleeve is provided with a wind wheel (14). 4. The double-rotor permanent magnet double-fed wind power generator according to claim 1 or 2, characterized in that, The three-phase rotor windings (6) are sequentially connected with brushes (9) and slip rings (11), and the three-phase rotor windings (6) are sequentially connected to the PWM converter on both sides of the rotor through the brushes (9) and slip rings (11), The three-phase excitation power is provided by the PWM converter on both sides of the rotor; The stator (1) includes: a stator core and a stator three-phase winding (5); the stator three-phase winding (5) and the three-phase rotor winding (6) are three-phase symmetrical AC windings. 5. The double-rotor permanent magnet double-fed wind power generator according to claim 4, characterized in that, There is an air gap between the permanent magnet (4) and the stator (1), the flux linkage generated by the permanent magnet (4) and the flux linkage generated by the three-phase rotor winding (6) connected to the AC excitation power supply in the air gap , and at the same time link with the magnetic field turns generated by the stator three-phase winding (5) to realize mixed excitation. 6. The double-rotor permanent magnet double-fed wind power generator according to claim 1 or 2, characterized in that, The number of poles of the permanent magnet outer rotor should be the same as that of the stator and the winding inner rotor; The permanent magnet outer rotor (3) is made of magnetically conductive material, the position of the permanent magnet (4) corresponds to the position of the three-phase rotor winding (6), and the magnetization direction of the permanent magnet (4) is radial magnetization. 7. The double-rotor permanent magnet double-fed wind power generator according to claim 1 or 2, characterized in that, The cylinder diameter of the first cylinder frame (23) is larger than the cylinder diameter of the second cylinder frame (24). 8. A power generation system based on double-rotor permanent magnet doubly-fed wind turbines, characterized in that it includes: stator main inductance L _s , stator resistance R _s , stator winding back electromotive force jω _s ψ _s , transformer L _m , winding In-wire rotor resistance R _r , wire-wound inner rotor inductance L _r , wire-wound inner rotor counter electromotive force jω _s1 ψ _r ; The wind wheel transmits the wind energy captured by the wind to the wound inner rotor, and the three-phase winding of the wound inner rotor rotates at a certain speed driven by the excitation voltage u _r on the rotor side and the wind wheel, and induces a three-phase voltage u _s on the stator , the flux linkage generated by the permanent magnet and the flux linkage generated by the three-phase rotor winding connected to the AC excitation power supply in the air gap, and at the same time linked with the magnetic field turn linkage generated by the stator three-phase winding, to achieve mixed excitation, in the stator main inductance Ls When it is larger than the stator resistance Rs, a larger magnetizing current _im will be generated; the permanent magnet installed on the outer rotor of the permanent magnet will generate an electromotive force u _P to reduce the magnetizing current _im required for operation; Stator induced three-phase voltage u _s , rotor side excitation voltage _ur , stator induced current is _s , rotor side excitation current _ir are stator and winding internal rotor voltage and current vectors respectively; ψ _s , ψ _r are stator and winding inner rotor voltage and current vectors respectively; In-line rotor flux vector, vector form F=Fd+jFq; ω _s and ω _s1 are grid synchronous angular frequency and motor slip angular frequency respectively; stator resistance R _s , stator main inductance L _s , winding inner rotor resistance R _r , winding inner rotor inductance L _r , transformer L _m , are the winding resistance, inductance and mutual inductance attributed to the stator and inner wound rotor respectively; Stator winding back electromotive force jω _s ψ _s winding inner rotor back electromotive force jω _s1 ψ _r is the counter electromotive force produced by stator and inner winding rotor winding respectively.