阅读说明：本技术 一种双馈型风力发电机用电磁齿轮箱及其控制方法 (Electromagnetic gear box for double-fed wind driven generator and control method thereof ) 是由 蔡彬 张健 秦清海 褚晓广 汲柏良 于 2021-03-03 设计创作，主要内容包括：本发明涉及一种双馈型风力发电机用电磁齿轮箱及其控制方法,属于风电领域。该电磁齿轮箱包括第一级行星电磁齿轮、第二级同轴磁齿轮、第三级同轴磁齿轮；第一级行星电磁齿轮包括电磁齿圈、行星磁齿轮、行星架、太阳磁齿轮等；电磁齿圈由铁芯和绕组组成。控制方法是：控制电磁齿圈绕组的极性,使启动时电磁齿圈的极对数为其额定极对数的一半,启动后电磁齿圈的极对数为其额定极对数；当风速大于额定风速,调节电磁齿圈的绕组电流,以调节第一级行星电磁齿轮的输出转矩,实现恒功率控制；当风速大于切出风速时,切除电磁齿圈的绕组电源,实现风轮与发电机解耦,降低发电机的制动力。本发明可降低运维成本；增速比能实时调节,可提升系统运行灵活性。(The invention relates to an electromagnetic gear box for a double-fed wind driven generator and a control method thereof, belonging to the field of wind power. The electromagnetic gear box comprises a first-stage planetary electromagnetic gear, a second-stage coaxial magnetic gear and a third-stage coaxial magnetic gear; the first-stage planetary electromagnetic gear comprises an electromagnetic gear ring, a planetary magnetic gear, a planet carrier, a sun magnetic gear and the like; the electromagnetic gear ring is composed of an iron core and a winding. The control method comprises the following steps: controlling the polarity of the electromagnetic gear ring winding to make the number of pole pairs of the electromagnetic gear ring be half of the rated number of pole pairs of the electromagnetic gear ring during starting, and the number of pole pairs of the electromagnetic gear ring after starting be the rated number of pole pairs of the electromagnetic gear ring; when the wind speed is higher than the rated wind speed, the winding current of the electromagnetic gear ring is adjusted to adjust the output torque of the first-stage planetary electromagnetic gear, so that constant power control is realized; when the wind speed is higher than the cut-out wind speed, the winding power supply of the electromagnetic gear ring is cut off, decoupling of the wind wheel and the generator is achieved, and braking force of the generator is reduced. The invention can reduce the operation and maintenance cost; the speed increasing ratio can be adjusted in real time, and the operation flexibility of the system can be improved.)

1. The utility model provides an electromagnetic gear box for doubly-fed type aerogenerator which characterized in that: the method comprises the following steps: the first-stage planetary electromagnetic gear, the second-stage coaxial magnetic gear and the third-stage coaxial magnetic gear are arranged on the same plane;

the first-stage planetary electromagnetic gear includes: the electromagnetic gear ring, the planetary magnetic gear, the planet carrier, the sun magnetic gear, the first-stage driving shaft and the first-stage driven shaft; the electromagnetic gear ring consists of a gear ring iron core and a winding; the first-stage driving shaft and the planet carrier are integrated, the planet magnetic gear is arranged on the planet carrier, and simultaneously, the planet magnetic gear, the electromagnetic gear ring and the sun magnetic gear are subjected to torque transmission through electromagnetic force; the shaft of the sun magnetic gear drives the first-stage driven shaft to rotate through a spline;

the second stage coaxial magnetic gear comprises: the second-stage driving shaft, the second-stage driven shaft and the second coaxial magnetic gear; the second coaxial magnetic gear consists of an outer rotor magnetic gear, an inner rotor magnetic gear and a magnetic adjusting ring; the outer rotor magnetic gear consists of an outer rotor iron core and a Halbach permanent magnet array adhered to the outer rotor iron core; the inner rotor magnetic gear consists of an inner rotor iron core and a Halbach permanent magnet array adhered to the inner rotor iron core; the magnetic adjusting ring is fixedly arranged between the outer rotor magnetic gear and the inner rotor magnetic gear;

the third stage coaxial magnetic gear comprises: the structure of the third-stage driving shaft, the third-stage driven shaft and the third coaxial magnetic gear is the same as that of the second-stage coaxial magnetic gear;

a first-stage driving shaft of the first-stage planetary electromagnetic gear is connected with a wind wheel main shaft through a shrinkage sleeve; a first-stage driven shaft of the first-stage planetary electromagnetic gear is connected with a second-stage driving shaft of the second-stage coaxial magnetic gear; a second-stage driven shaft of the second-stage coaxial magnetic gear is connected with a third-stage driving shaft of the third-stage coaxial magnetic gear, and a third-stage driven shaft of the third-stage coaxial magnetic gear is fixed with a coupler; the other end of the coupler is fixed with a rotating shaft of the double-fed wind driven generator;

the winding of the electromagnetic gear ring of the first-stage planetary electromagnetic gear is wired in the following mode: two ends of each two adjacent windings are respectively connected with a bus L1 and a bus L2, and two ends of the other two adjacent windings are respectively connected with a bus L3 and a bus L4; and by analogy, all the windings are respectively connected with the bus bars L1, L2, L3 and L4.

2. A control method of an electromagnetic gearbox for a doubly-fed wind generator according to claim 1, characterized in that: the method comprises the following steps:

step 1, when the wind speed reaches the cut-in wind speed, switching on a control power supply, and respectively connecting the buses L1 and L2 with the anode and the cathode of the control power supply; meanwhile, the buses L3 and L4 are respectively connected with the negative electrode and the positive electrode of the control power supply; at the moment, the number of pole pairs of the electromagnetic gear ring is half of the rated number of pole pairs of the electromagnetic gear ring, so that the speed increasing ratio of the first-stage planetary magnetic gear is reduced, the equivalent rotational inertia is reduced, the starting torque of the wind turbine generator is reduced, and low-wind-speed starting can be realized;

step 2, after starting, the buses L1 and L2 are still connected with the anode and the cathode of a control power supply respectively; meanwhile, the buses L3 and L4 are respectively connected with the positive pole and the negative pole of the control power supply; at the moment, the number of pole pairs of the electromagnetic gear ring is equal to the rated number of pole pairs of the electromagnetic gear ring, and normal operation is realized;

step 3, when the wind speed is greater than or equal to the rated wind speed, the winding current of the electromagnetic gear ring is adjusted, so that the magnetic flux density generated by the electromagnetic gear ring is reduced, the output torque of the first-stage planetary electromagnetic gear is adjusted, and the constant power control is realized;

and 4, when the wind speed is greater than or equal to the cut-out wind speed, cutting off the control power supply, and then losing power of the winding of the electromagnetic gear ring and generating no electromagnetic force, so that the first-stage planetary electromagnetic gear has no power output, the decoupling of the wind wheel and the generator is realized, and the braking force of the generator is greatly reduced.

Technical Field

The invention relates to a gear box and a control method thereof, in particular to an electromagnetic gear box for a double-fed wind driven generator and a control method thereof, and belongs to the technical field of wind power generation.

Background

The double-fed wind power generation system mainly comprises a wind wheel, a gear box, a double-fed wind power generator (DFIG), a converter system and the like. The DFIG is a high-speed, small-volume generator, and because the wind wheel is operating at a low rotational speed, a high-speed-ratio gearbox is usually used to increase the rotational speed of the low wind wheel to the rotational speed of the high-speed generator rotor. However, the existing gear box adopts mechanical gear engagement, needs a complex oil injection lubricating system, is large in size, heavy, high in cost, large in noise, high in failure rate and needs to be maintained regularly. Furthermore, the main losses of the doubly fed wind power system originate from the gearbox and converter system, wherein approximately 65% or so of the system losses originate from the gearbox. Therefore, it is necessary to research and use a new type of gear box to reduce the cost and loss of the system and improve the reliability of the system operation.

The magnetic gear has the characteristic of physical isolation and does not have mechanical contact, so the magnetic gear has the advantages of no abrasion, no maintenance, no noise, no need of lubrication, overload protection and the like, and more attention and application are paid in recent years. However, the existing magnetic gear cannot change the gear ratio in real time, and the application and popularization of the magnetic gear in a wind power generation system are influenced.

Disclosure of Invention

The main purposes of the invention are as follows: aiming at the defects and the blank in the prior art, the electromagnetic gear box is provided, has no mechanical contact, does not need lubrication, has small volume, light weight and low energy consumption, and can regulate and control the gear ratio in real time, thereby greatly reducing the operation and maintenance cost of the double-fed wind generating set and improving the reliability and the flexibility of the system.

In order to achieve the above object, the present invention provides an electromagnetic gear box for a doubly-fed wind generator, comprising: the device comprises a first-stage planetary electromagnetic gear, a second-stage coaxial magnetic gear, a third-stage coaxial magnetic gear and a master control system.

The first-stage planetary electromagnetic gear includes: the electromagnetic gear ring, the planetary magnetic gear, the planet carrier, the sun magnetic gear, the first-stage driving shaft and the first-stage driven shaft; the electromagnetic gear ring consists of a gear ring iron core and a winding; the first-stage driving shaft and the planet carrier are integrated, the planet magnetic gear is arranged on the planet carrier, and simultaneously, the planet magnetic gear, the electromagnetic gear ring and the sun magnetic gear are subjected to torque transmission through electromagnetic force; and the shaft of the sun magnetic gear drives the first-stage driven shaft to rotate through a spline.

The second stage coaxial magnetic gear comprises: the second-stage driving shaft, the second-stage driven shaft and the second coaxial magnetic gear; the second coaxial magnetic gear consists of an outer rotor magnetic gear, an inner rotor magnetic gear and a magnetic adjusting ring; the outer rotor magnetic gear consists of an outer rotor iron core and a Halbach permanent magnet array adhered to the outer rotor iron core; the inner rotor magnetic gear consists of an inner rotor iron core and a Halbach permanent magnet array adhered to the inner rotor iron core; the magnetic adjusting ring comprises a magnetic adjusting magnet block and a non-magnetic conducting material and is fixedly arranged between the outer rotor magnetic gear and the inner rotor magnetic gear.

The third stage coaxial magnetic gear comprises: and the structure of the third-stage driving shaft, the third-stage driven shaft and the third coaxial magnetic gear is the same as that of the second-stage coaxial magnetic gear.

A first-stage driving shaft of the first-stage planetary electromagnetic gear is connected with a wind wheel main shaft through a shrinkage sleeve; a first-stage driven shaft of the first-stage planetary electromagnetic gear is connected with a second-stage driving shaft of the second-stage coaxial magnetic gear; a second-stage driven shaft of the second-stage coaxial magnetic gear is connected with a third-stage driving shaft of the third-stage coaxial magnetic gear, and a third-stage driven shaft of the third-stage coaxial magnetic gear is fixed with a coupler; and the other end of the coupler is fixed with a rotating shaft of the double-fed wind driven generator.

The winding of the electromagnetic gear ring of the first-stage planetary electromagnetic gear is wired in the following mode: two ends of each two adjacent windings are respectively connected with a bus L1 and a bus L2, and two ends of the other two adjacent windings are respectively connected with a bus L3 and a bus L4; and by analogy, all the windings are respectively connected with the bus bars L1, L2, L3 and L4.

The electromagnetic gear box for the double-fed wind driven generator comprises the following steps:

step 1, when the wind speed reaches the cut-in wind speed, switching on a control power supply, and respectively connecting the buses L1 and L2 with the anode and the cathode of the control power supply; meanwhile, the buses L3 and L4 are respectively connected with the negative electrode and the positive electrode of the control power supply; at the moment, the number of pole pairs of the electromagnetic gear ring is half of the rated number of pole pairs of the electromagnetic gear ring, so that the speed increasing ratio of the first-stage planetary magnetic gear is reduced, the equivalent rotational inertia is reduced, the starting torque of the wind turbine generator is reduced, and low-wind-speed starting can be realized.

Step 2, after starting, the buses L1 and L2 are still connected with the anode and the cathode of a control power supply respectively; meanwhile, the buses L3 and L4 are respectively connected with the positive pole and the negative pole of the control power supply; at the moment, the number of pole pairs of the electromagnetic gear ring is equal to the rated number of pole pairs, and normal operation is realized.

And 3, when the wind speed is greater than or equal to the rated wind speed, regulating the winding current of the electromagnetic gear ring to reduce the magnetic flux density generated by the electromagnetic gear ring, so that the output torque of the first-stage planetary electromagnetic gear is regulated to realize constant power control.

And 4, when the wind speed is greater than or equal to the cut-out wind speed, cutting off the control power supply, and then losing power of the winding of the electromagnetic gear ring and generating no electromagnetic force, so that the first-stage planetary electromagnetic gear has no power output, the decoupling of the wind wheel and the generator is realized, and the braking force of the generator is greatly reduced.

The invention has the beneficial effects that:

1) mechanical contact is avoided, mechanical isolation is realized, mechanical vibration of the wind wheel cannot be transmitted to the rear stage, and the resonance problem can be effectively solved;

2) the double-fed wind generating set does not need lubrication, a complex oil injection lubrication system is omitted, and the double-fed wind generating set is small in size, light in weight and low in energy consumption, so that the operation and maintenance cost of the double-fed wind generating set can be greatly reduced;

3) the speed ratio can be regulated and controlled in real time, so that on one hand, the equivalent moment of inertia can be reduced, and low-wind-speed starting is realized; on the other hand, the wind wheel can assist constant power control, and can realize the decoupling of the wind wheel and the generator, thereby greatly reducing the braking force of the generator and improving the reliability and the flexibility of the system.

Drawings

Fig. 1 is a schematic view of a topology structure of a doubly-fed wind power generation system adopted in the present invention.

FIG. 2 is a schematic view of a first-stage planetary electromagnetic gear of the present invention.

FIG. 3 is a schematic view of a planetary magnetic gear in the first stage planetary electromagnetic gear of the present invention.

FIG. 4 is a schematic view of a second coaxial magnetic gear of the present invention.

FIG. 5 is a schematic view of the connection of the second stage coaxial magnetic gear and the third stage coaxial magnetic gear of the present invention.

Fig. 6 is a schematic diagram of a wiring mode of an electromagnetic ring gear winding in the first-stage planetary electromagnetic gear.

FIG. 7 is a circuit diagram of the polarity control of the electromagnetic ring gear winding in the first stage planetary electromagnetic gear of the present invention.

FIG. 8 is a schematic diagram of a second wiring mode of the electromagnetic ring gear winding in the first-stage planetary electromagnetic gear.

FIG. 9 is a third schematic diagram of the wiring mode of the electromagnetic ring gear winding in the first-stage planetary electromagnetic gear of the invention.

Fig. 10 is a fourth schematic diagram of the wiring mode of the electromagnetic ring gear winding in the first-stage planetary electromagnetic gear.

Wherein, 1-a first-stage planetary electromagnetic gear; 2-second stage coaxial magnetic gear; 3-third-stage coaxial magnetic gear; 4-a first-stage driving shaft; 5-a third-stage driven shaft; 6-wind wheel, 61-wind wheel main shaft; 7-a coupler; 8-double-fed wind power generator; 11-an electromagnetic gear ring; 12-sun magnetic gear; 13-planetary magnetic gear; 14-a planet carrier; 21-an outer rotor magnetic gear of a second coaxial magnetic gear; 22-a magnetic adjustment ring of the second coaxial magnetic gear; 23-an inner rotor magnetic gear of a second coaxial magnetic gear; 111-iron core of electromagnetic gear ring, 112-winding of electromagnetic gear ring; 131-permanent magnets of the planet magnetic gear; 132-iron core of planetary magnetic gear; 211-a Halbach permanent magnet array of a second coaxial magnetic gear outer rotor; 231-Halbach permanent magnet array of a second coaxial magnetic gear inner rotor.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, the doubly-fed wind power generation system adopted by the invention comprises a wind wheel 6, a main shaft 61 thereof, an electromagnetic gear box of the invention, a coupling 7 and a doubly-fed wind power generator 8; the electromagnetic gear box of the invention comprises: the device comprises a first-stage planetary electromagnetic gear 1, a second-stage coaxial magnetic gear 2, a third-stage coaxial magnetic gear 3 and a master control system.

As shown in fig. 1 and 2, the first-stage planetary electromagnetic gear 1 includes: the electromagnetic gear ring 11, the planet magnetic gear 13, the planet carrier 14, the sun magnetic gear 12, the first-stage driving shaft 4 and the first-stage driven shaft; the electromagnetic gear ring 11 is composed of a gear ring iron core 111 and a direct current winding 112; the primary drive shaft 4 is integrated with a carrier 14, and a planetary magnetic gear 13 is mounted on the carrier 14 while performing torque transmission with the electromagnetic ring gear 11 and the sun magnetic gear 12 by electromagnetic force. The shaft of the sun magnetic gear 12 drives the first-stage driven shaft to rotate through a spline. The number of the planetary magnetic gears 13 is 3 or more, and the specific number thereof is determined by the required transmission torque.

The planetary magnetic gear 13 includes permanent magnets 131 and an iron core 132, and a straight slot may be used between adjacent permanent magnets 131, or an inclined slot may be used as shown in fig. 3, so that cogging torque may be effectively reduced.

As shown in fig. 4 and 5, the second-stage coaxial magnetic gear 2 includes: the second-stage driving shaft, the second-stage driven shaft and the second coaxial magnetic gear; the second coaxial magnetic gear consists of an outer rotor magnetic gear 21, a magnetic adjusting ring 22 and an inner rotor magnetic gear 23, the outer rotor magnetic gear 21 consists of an outer rotor iron core and a Halbach permanent magnet array 211 adhered on the outer rotor iron core, and the number of pole pairs of the outer rotor magnetic gear 21 is P_oEach pole consists of a radial magnetized permanent magnet and a tangential magnetized permanent magnet; the inner rotor magnetic gear 23 consists of an inner rotor iron core and a Halbach permanent magnet array adhered to the inner rotor iron core, and the number of pole pairs of the inner rotor magnetic gear 23 is P_iEach pole consists of a radial magnetized permanent magnet and two permanent magnets with the magnetization angles of alpha and-alpha respectively distributed on two sides of the radial magnetized permanent magnet; the magnetic modulating ring 22 comprises N_sThe magnet adjusting block and the non-magnetic conductive material are fixedly arranged between the outer rotor magnetic gear 21 and the inner rotor magnetic gear 23. N is a radical of_sThe following formula is satisfied: n is a radical of_s＝P_o+P_i。

The third-stage coaxial magnetic gear 3 includes: and the structure of the third-stage driving shaft, the third-stage driven shaft and the third coaxial magnetic gear is the same as that of the second-stage coaxial magnetic gear 2.

As shown in fig. 1 and 5, a driving shaft 4 of a first-stage planetary electromagnetic gear 1 is connected with a wind wheel main shaft 61 through a shrinkage sleeve; the driven shaft of the first-stage planetary electromagnetic gear 1 is connected with the driving shaft of the second-stage coaxial magnetic gear 2; the driven shaft of the second-stage coaxial magnetic gear 2 is connected with the driving shaft of the third-stage coaxial magnetic gear 3, and the driven shaft 5 of the third-stage coaxial magnetic gear 3 is fixed with the coupler 7; the other end of the coupler 7 is fixed with a rotating shaft of the doubly-fed wind driven generator 8.

As shown in fig. 6, the winding 111 of the electromagnetic ring gear 11 of the first-stage planetary electromagnetic gear is wired as follows: two ends of two adjacent windings are respectively connected with the bus bars L1 and L2, and two ends of the other two adjacent windings are respectively connected with the bus bars L3 and L4. By analogy, all windings are respectively connected with the bus bars L1, L2, L3 and L4. The terminals X1, X2, X3, and X4 are connected to the bus bars L1, L2, L3, and L4, respectively.

As shown in fig. 7, the terminals X1, X2 are connected to the positive electrode (+), and the negative electrode (-) of the control power supply, respectively; pins K1:1 and K1:2 of the contactor K1 are respectively connected with an anode (+), and a cathode (-) of a control power supply, and pins K1:3 and K1:4 of the contactor K1 are respectively connected with terminals X3 and X4; pins K2:1 and K2:2 of the contactor K2 are respectively connected with a negative pole (-) and a positive pole (+) of a control power supply, and pins K2:3 and K2:4 of the contactor K2 are respectively connected with terminals X3 and X4.

The electromagnetic gear box for the double-fed wind driven generator comprises the following steps:

step 1, when the wind speed reaches the cut-in wind speed, the control power supply is switched on, as shown in fig. 7 and 8, the terminals X1 and X2 are respectively a positive pole (+), and a negative pole (-), and the buses L1 and L2 are also respectively a positive pole and a negative pole, so that all the electromagnetic ring gear windings connected with the bus L1 make the magnetic poles thereof be N poles, and all the electromagnetic ring gear windings connected with the bus L2 make the magnetic poles thereof be S poles. Meanwhile, as shown in fig. 7, the master control system keeps the contactor K1 open, and the control contactor K2 is closed, so that the terminals X3 and X4 are respectively connected to the negative pole (-) and the positive pole (+) of the control power supply, and the buses L3 and L4 are respectively the negative pole and the positive pole, so that all the electromagnetic ring gear windings connected to the bus L3 have the magnetic poles thereof in the S-pole state, and all the electromagnetic ring gear windings connected to the bus L4 have the magnetic poles thereof in the S-pole stateThe magnetic pole of the electromagnetic gear ring is N pole, so that the pole pair number P of the electromagnetic gear ring 11_bFor its rated pole pair number P_bNHalf (i.e., P)_b＝0.5P_bN) Therefore, the speed increasing ratio of the first-stage planetary electromagnetic gear 1 is reduced, the equivalent moment of inertia converted to a low-speed shaft (namely the first-stage driving shaft 4 of the first-stage planetary electromagnetic gear 1) is reduced, the starting torque of the wind turbine generator is reduced, and low-wind-speed starting can be realized.

The total speed increasing ratio i of the electromagnetic gear box is as follows:

in the formula, P_bIs the pole pair number, P, of the electromagnetic gear ring 11_aNumber of pole pairs, P, of the sun magnetic gear 13_oIs the number of pole pairs, P, of the outer rotor 21 of the second coaxial magnetic gear_iIs the number of pole pairs, P, of the inner rotor 23 of the second coaxial magnetic gear_o2Is the pole pair number, P, of the outer rotor of the third coaxial magnetic gear_i2The number of pole pairs of the inner rotor of the third coaxial magnetic gear.

As can be seen from equation (1), the pole pair number P of the electromagnetic ring gear 11_bAnd when the total speed increasing ratio i is smaller, the total speed increasing ratio i is also reduced. The equivalent moment of inertia is related to the square of the speed increasing ratio of each stage, so that the speed increasing ratio of the first-stage planetary electromagnetic gear 1 is reduced, the equivalent moment of inertia is reduced, and the wind turbine generator can be started at low wind speed.

Step 2, after the start, as shown in fig. 7 and 9, the terminals X1 and X2 are still connected to the positive pole (+), and the negative pole (-) of the control power supply, respectively, all the electromagnetic ring gear windings connected to the bus L1 still have their magnetic poles in the N-pole state, and all the electromagnetic ring gear windings connected to the bus L2 still have their magnetic poles in the S-pole state. Meanwhile, as shown in fig. 7, when the master control system controls the contactor K2 to be opened to close the contactor K1, the terminals X3 and X4 are respectively connected to the positive pole (+), and the negative pole (-) of the control power supply, and the buses L3 and L4 are respectively the positive pole and the negative pole, so that all the electromagnetic ring gear windings connected to the bus L3 have their magnetic poles in the N-pole state, all the electromagnetic ring gear windings connected to the bus L4 have their magnetic poles in the S-pole state, and at this time, the number P of pole pairs of the electromagnetic ring gear 11 is counted_bEqual to its nominal pole pair number P_bN(i.e., P)_b＝P_bN) And normal operation is realized.

And 3, when the wind speed is greater than or equal to the rated wind speed, adjusting the current of the electromagnetic gear ring winding 111 to reduce the magnetic flux density, so that the output torque of the first-stage planetary electromagnetic gear 1 is adjusted to realize constant power control. Further, if the wind speed is further increased, as shown in fig. 7 and 10, the main control system turns off the contactor K1 and the contactor K2, the terminals X3 and X4 are all de-energized, and the buses L3 and L4 are also all de-energized, so that all the electromagnetic gear ring windings connected with the bus L3 and the bus L4 are all de-energized, the magnetic poles of the electromagnetic gear ring windings are not in polarity, at this time, the number of pole pairs of the electromagnetic gear ring 11 is half of the rated number of pole pairs, the total speed increase ratio i is reduced, and the transmitted torque is also reduced, so that the output power of the first-stage planetary electromagnetic gear 1 can be reduced, and the constant power control is realized.

And 4, when the wind speed is greater than or equal to the cut-out wind speed, as shown in fig. 6, the main control system cuts off the control power supply, all windings 111 of the electromagnetic gear ring 11 lose power, and no electromagnetic force acts between the electromagnetic gear ring 11 and the planetary magnetic gear 13, so that no torque is transmitted, no power is output from the first-stage planetary electromagnetic gear 1, the wind wheel is decoupled from the generator, and the braking force of the generator is greatly reduced.