Wind generating set, differential speed regulation device and control method of differential speed regulation device

Abstract

The invention provides a wind generating set, a differential speed regulation device and a control method thereof, the wind generating set comprises the differential speed regulation device, a multi-port converter and an electro-magnetic synchronous generator, and the differential speed regulation device comprises a permanent magnet motor, a differential planetary gear train, a quasi planetary gear train and a speed regulation motor. A permanent magnet motor rotor is connected with a differential planetary gear train planet carrier, and a speed regulating motor rotor is connected with a quasi planetary gear train sun gear. The differential planetary gear train sun gear drives the electro-magnetic synchronous generator rotor to operate at a first preset rotating speed. One port of the multi-port converter is connected with the permanent magnet motor stator, one port is connected with the speed regulation motor stator, and the other port is connected with the electro-magnetic synchronous generator rotor through the slip ring. According to the differential speed regulation device, variable-speed input, self-energized speed regulation and constant-speed output are achieved, and the differential speed regulation device is compact in overall structure, small in size and light in weight; the black start can be realized without taking power from a power grid; and the electro-magnetic synchronous generator is directly connected to the grid, so that the power grid supporting capacity is high.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wind power generation, and in particular to a wind power generator set, a differential speed regulating device and a control method thereof. Background Art

[0002] The current mainstream wind turbines are mainly of three types: doubly-fed, semi-direct drive and direct drive. All of them require high-power converters to achieve grid connection, so that the unit exhibits current source characteristics to the grid and operates with the grid. The disadvantage is that the grid support capability is poor.

[0003] In order to improve the grid support capability, one approach is to increase the current capacity of the conversion device in the converter and adopt virtual synchronous generator (VSG) control to make the unit exhibit operating characteristics similar to those of a synchronous motor to the grid. However, its grid support capability is general and there is a risk of harmonic pollution and synchronous frequency resonance.

[0004] The other method is to install a speed regulating device at the front end of the generator to adjust the variable speed of the wind wheel to a constant speed, drive the synchronous motor, and directly use the synchronous motor as the grid-connected interface of the unit. Since the synchronous motor has inherent grid-building characteristics, it has strong grid support capabilities.

[0005] The front-end speed regulating device in the prior art has a complex structure, low reliability, large size and high cost. Summary of the invention

[0006] In order to overcome the defects in the prior art, the present disclosure provides a wind turbine generator set, a differential speed regulating device and a control method thereof.

[0007] The present invention solves the above technical problems through the following technical solutions:

[0008] In a first aspect, a differential speed regulating device is provided, which is applied to a wind turbine generator set, wherein the wind turbine generator set includes an electrically excited synchronous generator, and the differential speed regulating device includes a permanent magnet motor, a differential planetary gear train, a quasi-planetary gear train and a speed regulating motor;

[0009] The rotor of the permanent magnet motor is connected to the differential planetary gear train, the rotor of the speed regulating motor is connected to the quasi-planetary gear train, and the differential planetary gear train is connected to the quasi-planetary gear train and drives each other;

[0010] The differential planetary gear train is connected to the rotor of the electrically excited synchronous generator and drives the rotor of the electrically excited synchronous generator to operate at a first preset speed.

[0011] Preferably, the wind turbine generator set further comprises a first coupling;

[0012] The differential planetary gear train comprises a first sun gear, a first planet gear, a first planet carrier and a first ring gear; the first sun gear and the first planet gear are both located in the first ring gear, and the first planet gear is meshed with the inner teeth of the first ring gear and the first sun gear at the same time;

[0013] The quasi-planetary gear train comprises a second sun gear, a second planetary gear and a second ring gear; the second sun gear and the second planetary gear are both located in the second ring gear, and the second planetary gear is meshed with the inner teeth of the second ring gear and the second sun gear at the same time;

[0014] The rotor of the permanent magnet motor is coaxially fixedly connected to the first planet carrier, the rotor of the speed regulating motor is coaxially fixedly connected to the second sun gear, the first ring gear and the second ring gear are coaxially fixedly connected, and the first sun gear is connected to the electrically excited synchronous generator through the first coupling to drive the electrically excited synchronous generator to operate.

[0015] Preferably, the wind turbine generator set further comprises a wind wheel, the first planet carrier rotates based on a first real-time rotation speed and transmits the first real-time rotation speed to the first planet wheel, and the first real-time rotation speed is related to the rotation speed of the wind wheel;

[0016] The first ring gear rotates based on a second real-time rotation speed and transmits the second real-time rotation speed to the first planetary gear, wherein the second real-time rotation speed is related to the rotor rotation speed of the speed regulating motor;

[0017] The first planetary gear synthesizes the first preset speed corresponding to the first sun gear based on the first real-time speed and the second real-time speed, and the first sun gear outputs the first preset speed to the rotor of the electrically excited synchronous generator to drive the rotor of the electrically excited synchronous generator to operate.

[0018] Preferably, when the first real-time rotation speed is lower than the second preset rotation speed, the permanent magnet motor is in a power generation mode, the speed regulating motor is in an electric mode, and the first ring gear is used to drive the first planetary gear to rotate;

[0019] When the first real-time speed is higher than the second preset speed, the permanent magnet motor is in the electric mode, the speed regulating motor is in the power generation mode, and the first planetary gear is used to drive the first ring gear to rotate;

[0020] The second preset speed is determined based on the number of teeth of the first sun gear, the number of teeth of the first ring gear, and the first preset speed.

[0021] Preferably, when the external wind speed is less than or equal to the preset wind speed, the first real-time rotation speed is lower than the second preset rotation speed;

[0022] When the external wind speed is greater than the preset wind speed, the first real-time rotation speed is lower than the second preset rotation speed.

[0023] Preferably, the first coupling is a flexible coupling;

[0024] And / or, the quasi-planetary gear train further includes a third planetary gear, and the second planetary gear and the third planetary gear are coaxially fixedly connected.

[0025] Preferably, the wind turbine generator set further comprises a multi-port converter, and the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator are respectively electrically connected via the multi-port converter;

[0026] The multi-port converter is configured to provide a DC excitation current to a rotor of the electrically excited synchronous generator to generate a magnetic field;

[0027] The multi-port converter is further configured to transfer the electric energy output by the permanent magnet motor to the speed regulating motor based on the current wind rotor speed, so as to drive the speed regulating motor to operate at a corresponding speed;

[0028] Or the electric energy output by the speed regulating motor is transmitted to the permanent magnet motor to drive the permanent magnet motor to operate at a corresponding speed.

[0029] In a second aspect, a wind turbine generator set is also provided, wherein the wind turbine generator set comprises the differential speed regulating device described above.

[0030] Preferably, the wind turbine generator set further comprises a multi-port converter and an electrically excited synchronous generator;

[0031] The multi-port converter is electrically connected to the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator respectively, and is used to receive corresponding control signals to drive the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator to operate respectively.

[0032] Preferably, the wind turbine generator set further comprises a wind wheel, a main gear box, a second coupling and a high-speed shaft brake component;

[0033] The input end of the main gearbox is coaxially fixedly connected to the wind wheel, and the output end of the main gearbox is connected to the permanent magnet motor through the second coupling;

[0034] The main gearbox is used to increase the speed of the wind wheel of the wind wheel to a first real-time speed, and input the first real-time speed to the first planet carrier of the differential planetary gear train;

[0035] The high-speed shaft brake component is arranged at the output end of the main gear box, and the high-speed shaft brake component is used to stop the wind wheel.

[0036] Preferably, the second coupling is a flexible coupling.

[0037] Preferably, the wind turbine generator set further comprises a grid-connected switch, and the grid-connected switch is used to control the on-off between the electrically excited synchronous generator and the power grid;

[0038] And / or, the wind turbine generator set further includes a controller, and the controller is used to send the control signal to the multi-port converter.

[0039] In a third aspect, a control method of a differential speed regulating device is also provided, and the control method is implemented based on the differential speed regulating device described above; the control method comprises:

[0040] Acquire a second preset speed and a first real-time speed;

[0041] Determining whether the first real-time speed is higher than the second preset speed;

[0042] If it is higher, the permanent magnet motor is controlled to be in electric mode, and the speed regulating motor is controlled to be in power generation mode;

[0043] If it is lower than, the permanent magnet motor is controlled to be in the power generation mode, and the speed regulating motor is controlled to be in the electric mode.

[0044] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0045] The positive and progressive effects of this disclosure are:

[0046] The present disclosure provides a wind turbine generator set, a differential speed regulating device and a control method thereof. The wind turbine generator set includes a differential speed regulating device, a multi-port converter and an electrically excited synchronous generator. The differential speed regulating device includes a permanent magnet motor, a differential planetary gear train, a quasi-planetary gear train and a speed regulating motor. The rotor of the permanent magnet motor is connected to the planet carrier of the differential planetary gear train, and the rotor of the speed regulating motor is connected to the sun gear of the quasi-planetary gear train. The sun gear of the differential planetary gear train drives the rotor of the electrically excited synchronous generator to operate at a first preset speed. One port of the multi-port converter is connected to the stator of the permanent magnet motor, one port is connected to the stator of the speed regulating motor, and the other port is connected to the rotor of the electrically excited synchronous generator through a slip ring. The differential speed regulating device disclosed in the present disclosure realizes variable speed input, self-powered speed regulation and constant speed output, and has a compact overall structure, small size and light weight; it does not need to take electricity from the power grid and can be black-started; the electrically excited synchronous generator is directly connected to the grid, and the power grid support capacity is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A first structural schematic diagram of a wind turbine generator set provided by the present disclosure;

[0048] Figure 2 A second structural schematic diagram of a wind turbine generator set provided by the present disclosure;

[0049] Figure 3 A schematic diagram of the structure of the differential speed regulating device provided by the present disclosure;

[0050] Figure 4 A third structural schematic diagram of a wind turbine generator set provided by the present disclosure;

[0051] Figure 5 A schematic diagram of the rotor speed-power variation with wind speed of the wind turbine generator set provided by the present invention;

[0052] Figure 6 A schematic diagram of the main gearbox output speed-power variation with wind speed of the wind turbine generator set provided by the present invention;

[0053] Figure 7 A schematic diagram of the first planet carrier speed, the first ring gear speed and the first sun gear speed of the differential planetary gear train of the wind generator set provided by the present disclosure changing with wind speed;

[0054] Figure 8 A schematic diagram of the change of the speed and power of the permanent magnet motor of the wind generator set provided by the present invention with the wind speed;

[0055] Fig. 9 A schematic diagram of the speed and power of the speed regulating motor of the wind turbine generator set provided by the present invention changing with wind speed;

[0056] Fig.10 A schematic diagram of the first gear ring speed and power of the wind generator set provided by the present disclosure changing with wind speed;

[0057] Fig.11 A schematic diagram of the speed and power of the electrically excited synchronous generator of the wind turbine generator set provided by the present disclosure changing with wind speed;

[0058] Fig.12 A schematic flow chart of a control method for a differential speed regulating device provided in the present invention. DETAILED DESCRIPTION

[0059] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0060] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0061] In the embodiments of the present disclosure, the collection, storage, use, processing, transmission, provision and disclosure of user personal information involved are in compliance with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0062] Example 1

[0063] This embodiment provides a differential speed regulating device, which is applied to a wind turbine generator set. Figure 1 The wind turbine generator set includes an electrically excited synchronous generator 1, and the differential speed regulating device 2 includes a permanent magnet motor 21, a differential planetary gear train 22, a quasi-planetary gear train 23 and a speed regulating motor 24;

[0064] The rotor of the permanent magnet motor 21 is connected to the differential planetary gear train 22, the rotor of the speed regulating motor 24 is connected to the quasi-planetary gear train 23, and the differential planetary gear train 22 and the quasi-planetary gear train 23 are connected and drive each other;

[0065] The differential planetary gear train 22 is connected to the rotor of the electrically excited synchronous generator 1 and drives the rotor of the electrically excited synchronous generator 1 to rotate at a first preset speed.

[0066] Specifically, the permanent magnet motor includes a stator and a rotor, and the speed regulating motor includes a stator and a rotor. Both the permanent magnet motor and the speed regulating motor are existing mature components, and their specific structures will not be described in detail here.

[0067] The differential speed regulating device disclosed in the present invention realizes that no matter whether the external wind speed is high or low, the differential planetary gear train can stably drive the electrically excited synchronous generator to operate at a first preset constant speed through the mutual coordination and transmission of the permanent magnet motor, the differential planetary gear train, the quasi-planetary gear train, and the speed regulating motor. The differential speed regulating device realizes variable speed input, self-powered speed regulation, and constant speed output, and has a compact overall structure, small size, and light weight.

[0068] In an alternative embodiment, see Figure 2 and Figure 3 , the wind turbine generator set further comprises a first coupling 6;

[0069] The differential planetary gear train 22 includes a first sun gear 221, a first planetary gear 222, a first planet carrier 223 and a first ring gear 224. The first sun gear 221 and the first planetary gear 222 are both located in the first ring gear 224. The first planetary gear 222 is meshed with the inner teeth of the first ring gear 224 and the first sun gear 221 at the same time.

[0070] The quasi-planetary gear train 23 includes a second sun gear 231, a second planetary gear 232, a second ring gear 233, and a second planet carrier 234. The second sun gear 231 and the second planetary gear 232 are both located in the second ring gear 233. The second planetary gear 232 is meshed with the inner teeth of the second ring gear 233 and the second sun gear 231 at the same time.

[0071] The rotor 211 of the permanent magnet motor 21 is coaxially fixedly connected to the first planetary carrier 223, the rotor 241 of the speed regulating motor 24 is coaxially fixedly connected to the second sun gear 231, the first ring gear 224 and the second ring gear 233 are coaxially fixedly connected, and the first sun gear 221 is connected to the electrically excited synchronous generator 1 through the first coupling 6 to drive the electrically excited synchronous generator 1 to operate.

[0072] like Figure 1 and Figure 2 As shown, the first planet carrier 223 of the differential planetary gear train 22 is driven by the wind wheel 5 through the main gear box 4 and the second coupling 7, the first ring gear 224 is driven by the speed regulating motor 24 and the second ring gear 233 after being decelerated by the quasi-planetary gear train 23, and the first planetary gear 222 drives the first sun gear 221 to operate. The first planetary gear 222 plays the role of synthesis and decomposition of motion. When the speed of the first planet carrier 223 is low, the first planet carrier 223 drives the first planetary gear 222 to operate as input, and the first ring gear 224 also drives the first planetary gear 222 to operate as input, and the first planetary gear 222 drives the first sun gear 221 as output; when the speed of the first planet carrier 223 is high, the first planet carrier 223 drives the first planetary gear 222 to operate as input, and the first planetary gear 222 drives the first ring gear 224 and the first sun gear 221 as output.

[0073] The first gear ring and the second gear ring are coaxially fixedly connected. When the first gear ring rotates around the axis, the second gear ring will also rotate around the axis, thereby driving the speed regulating motor to operate; or the speed regulating motor drives the second gear ring to operate. When the second gear ring rotates around the axis, the first gear ring will also rotate around the axis.

[0074] The rotor of the permanent magnet motor is coaxially fixedly connected to the first planet carrier of the differential planetary gear system, the rotor of the speed regulating motor is coaxially fixedly connected to the second sun gear of the quasi-planetary gear system, the first ring gear of the differential planetary gear system and the second ring gear of the quasi-planetary gear system are coaxially fixedly connected, and the first sun gear of the differential planetary gear system is connected to the electrically excited synchronous generator through a first coupling; so that the permanent magnet motor and the first planet carrier run at the same speed, the speed regulating motor and the second sun gear run at the same speed, the first ring gear and the second ring gear run at the same speed, and the first sun gear and the electrically excited synchronous generator run at the same speed, thereby realizing the transmission of speed.

[0075] The differential speed regulating device of this embodiment, the differential planetary gear train includes a first planet carrier and a first sun gear. No matter whether the rotation speed of the first planet carrier is high or low, the first sun gear can stably drive the electrically excited synchronous generator to operate at a first preset constant speed through the mutual coordination and transmission between the permanent magnet motor, the differential planetary gear train, the quasi-planetary gear train and the speed regulating motor. The differential speed regulating device realizes variable speed input, self-powered speed regulation and constant speed output, and has a compact overall structure, small size and light weight.

[0076] In an optional embodiment, if Figure 1 , Figure 2 and Figure 4 As shown, the wind turbine generator set further includes a wind rotor 5, the first planet carrier 223 rotates based on a first real-time rotation speed, and transmits the first real-time rotation speed to the first planetary gear 222, and the first real-time rotation speed is related to the rotation speed of the wind rotor;

[0077] The first ring gear 224 rotates based on the second real-time speed and transmits the second real-time speed to the first planetary gear 222, where the second real-time speed is related to the rotor speed of the speed regulating motor;

[0078] The first planetary gear 222 synthesizes the first preset speed corresponding to the first sun gear 221 based on the first real-time speed and the second real-time speed. The first sun gear 221 outputs the first preset speed to the rotor of the electrically excited synchronous generator 1 to drive the rotor of the electrically excited synchronous generator 1 to operate.

[0079] In an optional embodiment, when the first real-time speed is lower than the second preset speed, the permanent magnet motor is in a power generation mode, the speed regulating motor is in a motoring mode, and the first ring gear is used to drive the first planetary gear to rotate;

[0080] When the first real-time speed is higher than the second preset speed, the permanent magnet motor is in the electric mode, the speed regulating motor is in the power generation mode, and the first planetary gear is used to drive the first ring gear to rotate;

[0081] The second preset speed is determined based on the number of teeth of the first sun gear, the number of teeth of the first ring gear and the first preset speed.

[0082] Specifically, the second preset rotation speed is less than the first preset rotation speed.

[0083] Specifically, the first real-time rotation speed is positively correlated with the rotation speed of the wind wheel, and the external wind speed is positively correlated with the rotation speed of the wind wheel.

[0084] Specifically, when the first real-time speed is lower than the second preset speed, the permanent magnet motor is in the power generation mode, the speed regulation motor is in the electric mode, and the first ring gear obtains power from the outside to rotate the first planetary gear to ensure that the first sun gear constantly outputs the first preset speed. At this time, the first ring gear accelerates the first planetary gear.

[0085] When the first real-time speed is higher than the second preset speed, the permanent magnet motor is in electric mode, the speed regulating motor is in power generation mode, and the first ring gear outputs power to the outside so that the first planetary gear drives the first ring gear to rotate, so as to ensure that the first sun gear constantly outputs the first preset speed. At this time, the first ring gear acts to slow down the first planetary gear.

[0086] Simply obtaining power from the outside or outputting power to the outside by the first gear ring will cause the corresponding speed control motor to have excessive power. Only when the maximum power obtained by the first gear ring from the outside at medium and low wind speeds is equal to the maximum power output to the outside at medium and high wind speeds, the power of the speed control motor is minimum. That is, when the maximum power of the speed control motor in the electric and generating modes is equal, the power of the speed control motor is minimum and the cost is lower.

[0087] In the differential speed regulating device of this embodiment, the permanent magnet motor and the speed regulating motor can switch the working state according to the first real-time speed. Regardless of whether the first real-time speed is high or low, the first preset speed can be stably output to the electrically excited synchronous generator through the mutual cooperation and transmission of the permanent magnet motor, the differential planetary gear train, the quasi-planetary gear train and the speed regulating motor to drive the electrically excited synchronous generator to operate at a constant speed, thereby improving the environmental adaptability of the differential speed regulating device. At the same time, the differential speed regulating device realizes variable speed input, self-powered speed regulation, and constant speed output, and the overall structure is compact, small in size, and light in weight.

[0088] In an optional implementation, when the external wind speed is less than or equal to the preset wind speed, the first real-time rotation speed is lower than the second preset rotation speed;

[0089] When the external wind speed is greater than the preset wind speed, the first real-time rotation speed is lower than the second preset rotation speed.

[0090] Specifically, the first real-time rotation speed is positively correlated with the external wind speed.

[0091] If the outside wind speed is less than or equal to the preset wind speed, that is, the outside wind speed is low, the first real-time speed is relatively low. When the first real-time speed is lower than the second preset speed, the first ring gear needs to obtain power from the outside to rotate the first planetary gear to ensure that the first sun gear constantly outputs the first preset speed. At this time, the permanent magnet motor is in the power generation mode, and the speed regulation motor is in the electric mode.

[0092] If the external wind speed is greater than the preset wind speed, that is, the external wind speed is high, the first real-time speed is relatively high. When the first real-time speed is higher than the second preset speed, the first ring gear needs to output power to the outside so that the first planetary gear drives the first ring gear to rotate, so as to ensure that the first sun gear constantly outputs the first preset speed. At this time, the permanent magnet motor is in the electric mode, and the speed regulating motor is in the power generation mode.

[0093] Specifically, the preset wind speed can be medium wind speed. The external wind speed lower than the medium wind speed is called low wind speed, and the external wind speed higher than the medium wind speed is called high wind speed. When the external wind speed is medium and low wind speed, the first real-time rotation speed is lower than the second preset rotation speed. When the external wind speed is medium and high wind speed, the first real-time rotation speed is higher than the second preset rotation speed.

[0094] In the differential speed regulating device of the present embodiment, the permanent magnet motor and the speed regulating motor can switch the working state according to the external wind speed. No matter whether the external wind speed is high or low, the permanent magnet motor, the differential planetary gear train, the quasi-planetary gear train and the speed regulating motor can cooperate and transmit with each other to stably output the first preset speed to the electrically excited synchronous generator, so as to drive the electrically excited synchronous generator to operate at a constant speed, thereby further improving the environmental adaptability of the differential speed regulating device. At the same time, the differential planetary gear train is small in size and compact in structure, thereby reducing the size of the speed regulating device.

[0095] In an optional embodiment, the first coupling is a flexible coupling.

[0096] A flexible coupling is used to connect the first sun gear and the electrically excited synchronous generator, which effectively reduces the mutual influence of the impact load on the connected components and ensures the stable operation of the electrically excited synchronous generator.

[0097] In an optional embodiment, if Figure 3 As shown, the quasi-planetary gear train 23 further includes a third planetary gear 235; the second planetary gear 232 and the third planetary gear 235 are coaxially fixedly connected.

[0098] In an optional embodiment, if Figure 1 , Figure 2 and Figure 4 As shown, the wind turbine generator set further includes a multi-port converter 3, and the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator 1 are electrically connected through the multi-port converter 3 respectively;

[0099] The multi-port converter is configured to provide a DC excitation current to a rotor of an electrically excited synchronous generator, that is, to provide a DC excitation current to a rotor winding of the generator to generate a magnetic field;

[0100] The multi-port converter is also configured to transfer the electric energy output by the permanent magnet motor to the speed regulating motor based on the current wind rotor speed, so as to drive the speed regulating motor to operate at a corresponding speed;

[0101] Or the electric energy output by the speed regulating motor is transmitted to the permanent magnet motor to drive the permanent magnet motor to operate at a corresponding speed.

[0102] The permanent magnet motor, speed regulating motor and electrically excited synchronous generator in the present invention are electrically connected to corresponding ports of the multi-port converter, and the multi-port converter can control the speed of the speed regulating motor and the permanent magnet motor according to the change of the current wind wheel speed.

[0103] Since the rotor of the permanent magnet motor is coaxially fixedly connected to the first planetary frame of the differential planetary gear system, the wind wheel of the wind turbine generator set rotates, and the permanent magnet motor can rotate. The stator of the permanent magnet motor is electrically connected to the multi-port converter. As long as the wind wheel rotates, an alternating current can be generated in the stator of the permanent magnet motor and the multi-port converter circuit. The alternating current is first rectified by the multi-port converter, and then inverted by the multi-port converter into an alternating current of the required frequency based on a corresponding speed control signal to drive the speed regulating motor to rotate at the required speed.

[0104] When the outside wind speed is low, the current wind wheel speed is low. At this time, the permanent magnet motor is in the power generation mode. The electric energy output by the permanent magnet motor is transmitted to the speed regulating motor through the inverter, so that the speed regulating motor rotates at the required speed. At this time, the speed regulating motor is in the electric mode; at the same time, the electric energy output by the permanent magnet motor is transmitted to the electrically excited synchronous generator through the inverter, providing a DC excitation current for the rotor of the electrically excited synchronous generator to generate a magnetic field.

[0105] When the outside wind speed is high, the current wind wheel speed is high. At this time, the speed regulating motor is in the power generation mode. The electric energy output by the speed regulating motor is transmitted to the permanent magnet motor through the inverter, so that the permanent magnet motor rotates at the required speed. At this time, the permanent magnet motor is in the electric mode; at the same time, the electric energy output by the speed regulating motor is transmitted to the electrically excited synchronous generator through the inverter, providing a DC excitation current for the rotor of the electrically excited synchronous generator to generate a magnetic field.

[0106] The inventors also found that the existing front-end speed control device using a differential planetary variable frequency motor, the frequency converter in the speed control device draws power from the power grid through a transformer and drives the servo motor to drive the differential planetary sun gear for speed regulation, thereby achieving a constant speed input for the electrically excited synchronous generator. However, since the frequency converter must be connected to the power grid, it will cause pollution to the power grid.

[0107] In the differential speed regulating device of this embodiment, the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator form a power self-closing system through the converter, which avoids the connection between the speed regulating motor and the power grid through the converter, realizes the unification of the wind turbine generator set and the conventional power plant in the grid-connected interface, avoids the influence of the grid fluctuation on the speed regulating motor, and the speed regulating motor does not need to draw power from the grid, the grid support capacity is strong, and will not cause pollution and interference to the grid; the DC excitation current of the electrically excited synchronous generator draws power from the DC bus side of the multi-port converter, and the size of the DC excitation current is controlled by the main control, which meets the reactive power regulation needs of the power grid.

[0108] Combine the following Figure 3 , the operation process of the differential speed regulating device of this embodiment under medium-low wind speed and medium-high wind speed conditions is further explained.

[0109] See also Figure 3 The rotor 241 of the speed regulating motor 24 is coaxially fixedly connected with the second sun gear 231 of the quasi-planetary gear train 23 and rotates together at the same speed. The second planet carrier 234 of the quasi-planetary gear train 23 is fixedly connected to the housing.

[0110] When the external wind speed is medium or low, that is, when the first real-time speed is lower than the second preset speed, the second sun gear 231 drives the second planetary gear 232 to rotate, the second planetary gear 232 is coaxially fixedly connected with the third planetary gear 235 and fixed as a whole, the second planetary gear 232 drives the second ring gear 233 to rotate, the first ring gear 224 and the second ring gear 233 are coaxially fixedly connected and fixed as a whole, so far, the rotor 241 of the speed regulating motor 24 slows down the speed of the speed regulating motor through the quasi-planetary gear train 23 and transmits it to the first ring gear 224, and the first ring gear 224 obtains the second real-time speed.

[0111] Through the differential planetary gear train 22, the first real-time speed of the wind turbine rotor input to the first planet carrier 223 is superimposed with the second real-time speed input to the first ring gear 224 through the first planetary gear 222, and then output to the electrically excited synchronous generator 1 at a constant first preset speed of the first sun gear 221. At this time, the first ring gear 224 obtains power from the outside, the first ring gear 224 drives the first planetary gear 222 to rotate, the permanent magnet motor 21 is in the power generation mode, and the speed regulating motor 24 is in the electric mode.

[0112] For a wind turbine generator set equipped with a multi-port converter, since the rotor of the permanent magnet motor is coaxially fixedly connected to the first planetary frame of the differential planetary gear system, the permanent magnet motor can rotate when the wind wheel of the wind turbine generator set rotates, and the stator of the permanent magnet motor is electrically connected to the multi-port converter. As long as the wind wheel rotates, an alternating current can be generated in the stator of the permanent magnet motor and the multi-port converter circuit. The alternating current is first rectified by the multi-port converter, and then inverted by the multi-port converter into an alternating current of the required frequency based on the corresponding speed control signal to drive the speed regulating motor to rotate at the required speed.

[0113] When the external wind speed is medium or high, that is, when the first real-time speed is higher than the second preset speed, since the first real-time speed input by the wind wheel to the first planetary carrier 223 is relatively high, in order to ensure that the first preset speed output by the first sun gear 221 is constant, the first planetary gear 222 drives the first gear ring 224 to output the speed outward, rather than the speed regulating motor 24 giving it a speed, which is equivalent to the first gear ring 224 driving the speed regulating motor 24 to operate, and the speed regulating motor 24 is driven to enter the power generation mode. At this time, the first planetary gear 222 drives the first gear ring 224 to rotate, the permanent magnet motor 21 is in the electric mode, and the speed regulating motor 24 is in the power generation mode.

[0114] The working principle of the present invention is further explained below:

[0115] To ensure that the first preset speed output by the first sun gear of the differential planetary gear train is constant, the first ring gear of the differential planetary gear train is adjusted in real time according to the first planet carrier input speed (i.e., the first real-time speed), and the relationship is:

[0116] ;

[0117] Where: is the characteristic coefficient of the differential planetary gear train, specifically the ratio of the number of teeth of the first ring gear to the number of teeth of the first sun gear; Input a speed for the first planet carrier, i.e., a first real-time speed; is the speed of the first ring gear, It is the first sun gear speed, that is, the first preset speed, which can also be called the speed of the electrically excited synchronous generator.

[0118] For a specific differential planetary gear train, is a fixed value, is also a constant value, as The improvement The speed is gradually reduced and the direction of rotation is changed, that is, the first gear ring outputs power to the outside, the speed regulating motor enters the power generation mode, and the corresponding permanent magnet motor also switches from the power generation mode to the electric mode.

[0119] In a specific example, the differential planetary gear train characteristic coefficient k=2.16, the first sun gear speed =1500, the second preset speed is 474.4, where the second preset speed is the first gear ring speed The first real-time speed corresponding to 0 According to the above formula, we can know that:

[0120] ;

[0121] when is 0, , it can be seen that the second preset speed is less than the first preset speed, and the second preset speed can be calculated to be 474.7.

[0122] The first ring gear speed With the first real speed The relationship is:

[0123] ;

[0124] When the first real-time speed hour, , the first ring gear plays a role in accelerating the first planetary gear;

[0125] When the first real-time speed hour, The first ring gear serves to reduce the speed of the first planetary gear;

[0126] Differential planetary gear train torque relationship:

[0127] ;

[0128] Where: is the characteristic coefficient of the differential planetary gear train, specifically the ratio of the number of teeth of the first ring gear to the number of teeth of the first sun gear, is the output torque of the first sun gear, is the output torque of the first ring gear, Input torque to the first planet carrier, input is positive and output is negative.

[0129] It can be seen that the torque only depends on the characteristic coefficient of the differential planetary gear train Related. Power of the first ring gear:

[0130] ;

[0131] when When, due to ,but , indicating that the first ring gear obtains power from the outside, the first ring gear drives the first planetary gear to rotate, and the first planetary carrier drives the first planetary gear to rotate, and the first sun gear rotates at a constant speed.

[0132] when When, due to ,but , indicating that the first ring gear outputs power to the outside, the first planetary gear drives the first ring gear to rotate, the first ring gear runs at a variable speed, and the first sun gear runs at a constant speed.

[0133] ;

[0134] because is a fixed value, Also a constant value, the speed of the first gear ring The size depends on the first real-time speed size.

[0135] For a wind turbine generator set equipped with a main gearbox, the output speed of the main gearbox is the first real-time speed. Specifically, the output speed of the main gearbox is the main gearbox speed ratio multiplied by the rotor speed of the wind turbine generator set.

[0136] If the speed of the main gearbox input to the differential planetary gear train is less than 474.7 under all working conditions, the first ring gear needs to obtain power from the outside to ensure that the first sun gear outputs the first preset speed constantly. If the speed of the main gearbox input to the differential planetary gear train is greater than 474.7 under all working conditions, the first ring gear needs to output power to the outside to ensure that the first sun gear outputs the first preset speed constantly. If the speed of the main gearbox input to the differential planetary gear train fluctuates around 474.7 under all working conditions, the first ring gear obtains power from the outside and also outputs power to the outside.

[0137] The first gear ring simply obtains power from the outside or outputs power to the outside, which will cause the corresponding speed regulating motor to have excessive power. Only when the maximum power obtained by the first gear ring from the outside at medium and low wind speeds is equal to the maximum power output to the outside at medium and high wind speeds, the power of the speed regulating motor is minimum, that is, when the maximum power of the speed regulating motor in the motoring and generating modes is equal, the power of the speed regulating motor is minimum and the cost is low.

[0138] The rotor of the permanent magnet motor is fixed to the first planetary carrier of the differential planetary gear system and rotates together. Accordingly, at medium and low wind speeds, the permanent magnet motor is in power generation mode and the speed regulating motor is in electric mode; at medium and high wind speeds, the permanent magnet motor is in electric mode and the speed regulating motor is in power generation mode.

[0139] Example 2

[0140] This embodiment provides a wind turbine generator set, such as Figure 1 , Figure 2 and Figure 4 As shown, the wind turbine generator set includes a differential speed regulating device 2 implemented in 1.

[0141] The wind turbine generator set of this embodiment includes the differential speed regulating device in Embodiment 1, and the differential speed regulating device includes a permanent magnet motor, a differential planetary gear train, a quasi-planetary gear train and a speed regulating motor. Through the mutual coordination and transmission of the permanent magnet motor, the differential planetary gear train, the quasi-planetary gear train and the speed regulating motor, it is achieved that no matter whether the external wind speed is high or low, the differential planetary gear train can stably drive the electrically excited synchronous generator to operate at a first preset constant speed. The differential speed regulating device realizes variable speed input, self-powered speed regulation and constant speed output. The overall structure is compact, small in size and light in weight. Due to the use of a permanent magnet motor, the transformer, connecting cables, etc. are reduced, and the structure of the wind turbine generator set is further simplified.

[0142] In an optional embodiment, if Figure 1 , Figure 2 and Figure 4 As shown, the wind turbine generator set further includes a multi-port converter 3 and an electrically excited synchronous generator 1;

[0143] The multi-port converter is electrically connected to the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator respectively, and is used to receive corresponding control signals to drive the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator to operate respectively.

[0144] Since the rotor of the permanent magnet motor is coaxially fixedly connected to the first planetary frame of the differential planetary gear system, the wind wheel of the wind turbine generator set rotates, and the permanent magnet motor can rotate. The stator of the permanent magnet motor is electrically connected to the multi-port converter. As long as the wind wheel rotates, an alternating current can be generated in the stator of the permanent magnet motor and the multi-port converter circuit. The alternating current is first rectified by the multi-port converter, and then inverted by the multi-port converter into an alternating current of the required frequency based on a corresponding speed control signal to drive the speed regulating motor to rotate at the required speed.

[0145] like Figure 4 As shown, the multi-port converter includes two DC / AC (direct current / alternating current) converters and one DC / DC (direct current / direct current) converter, wherein an AC port of a DC / AC converter in the multi-port converter is electrically connected to the stator of the permanent magnet motor, an AC port of another DC / AC converter in the multi-port converter is electrically connected to the stator of the speed regulating motor, and a DC port of the DC / DC converter in the multi-port converter is electrically connected to a rotor slip ring interface of an electrically excited synchronous generator.

[0146] The multi-port converter can control the speed of the speed regulating motor and the permanent magnet motor according to the change of the speed of the wind rotor in the wind turbine generator set.

[0147] The wind turbine generator set of this embodiment includes the differential speed regulating device in Embodiment 1, and the differential speed regulating device includes a permanent magnet motor, a differential planetary gear train, a quasi-planetary gear train and a speed regulating motor. The permanent magnet motor and the speed regulating motor form a power self-closing system through a multi-port converter, thereby avoiding the connection between the speed regulating motor and the power grid through the multi-port converter, realizing the unification of the wind turbine generator set and the conventional power plant in the grid-connected interface, avoiding the influence of the power grid fluctuation on the speed regulating motor, and the speed regulating motor does not need to draw power from the power grid, the power grid support capacity is strong, and will not cause pollution and interference to the power grid, truly realizing the goal of "grid-friendly" wind turbine generator set, so that the wind turbine generator set can realize the black start function; at the same time, due to the use of permanent magnet motors, transformers, connecting cables, etc. are reduced, and the structure of the wind turbine generator set is simplified.

[0148] In an optional embodiment, if Figure 4 As shown, the wind turbine generator set includes a wind wheel 5, a main gear box 4, a second coupling 7 and a high-speed shaft brake component 8;

[0149] The input end of the main gearbox 4 is coaxially fixedly connected to the wind wheel 5, and the output end of the main gearbox 4 is connected to the first planet carrier through the second coupling 7;

[0150] The main gearbox 4 is used to increase the speed of the wind wheel 5 to a first real-time speed, and input the first real-time speed to the first planet carrier;

[0151] The high-speed shaft brake component 8 is arranged at the output end of the main gear box 4 , and the high-speed shaft brake component 8 is used to stop the wind wheel 5 .

[0152] Since differential planetary transmission is adopted in the differential speed regulating device, if a brake component is set after the differential speed regulating device, the brake component must be set not only on the rotor of the speed regulating motor, but also on the output shaft of the first sun gear. The disadvantages are obvious. On the one hand, there is one more set of brake components, which makes the structure complicated. On the other hand, the shutdown control is complicated. A high-speed shaft brake component is set on the high-speed shaft side of the output end of the main gearbox. Compared with the existing multiple sets of traditional brake components, the number of brake components is reduced, the structure of the wind turbine is simplified, the structure is simple, and it is easy to operate. The wind turbine generator set of this embodiment uses a split design, which can reduce the speed ratio of the traditional gearbox and greatly improve the reliability of the main gearbox.

[0153] The traditional main gearbox has a large speed ratio, a high speed shaft speed, and low reliability of the high-speed shaft system. In particular, failure of the high-speed shaft gear can easily cause failure of the entire gearbox, which will result in the entire gearbox being taken down the tower for repair, with high repair costs. In the wind turbine generator set of this embodiment, the planetary gear system in the differential speed control device is separated from the main gearbox, which reduces the repair cost when the main gearbox fails.

[0154] In an optional embodiment, the second coupling is a flexible coupling.

[0155] In the wind turbine generator set of this embodiment, the differential speed regulating device is connected to the main gear box via a flexible coupling, which effectively reduces the mutual influence of the impact load on the connected components.

[0156] In an optional embodiment, if Figure 4 As shown, the wind turbine generator set further includes a grid-connected switch 9 , which is used to control the on-off between the electrically excited synchronous generator 1 and the power grid 10 .

[0157] In an optional embodiment, the wind turbine generator set further includes a controller, and the controller is used to send a control signal to the converter.

[0158] For electrically excited synchronous generators, the DC excitation current of the electrically excited synchronous generator is powered by the DC bus side of the converter, and the magnitude of the excitation current is controlled by a controller. Specifically, the controller controls the excitation current through the DC / DC converter in the multi-port converter according to the grid demand to meet the reactive power regulation needs of the grid.

[0159] The wind turbine generator set of this embodiment uses a multi-port converter to integrate the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator into a whole, and uses one controller for control, which is convenient for centralized control.

[0160] Figure 5 The example shows the change of the rotor speed-power of the wind turbine with the wind speed. It can be seen that based on the speed regulation of the differential speed regulating device, as the wind speed increases, the rotor speed and power will first gradually increase and then finally stabilize.

[0161] Figure 6 The output speed of the main gearbox (i.e., the speed of the first planet carrier of the differential planetary gear system) - power changes with wind speed. The speed ratio of the main gearbox of the wind turbine generator set is 56.38. It can be seen that based on the speed regulation of the differential speed regulating device, as the wind speed increases, the output speed and power of the main gearbox will first gradually increase and then eventually stabilize.

[0162] Figure 7 The figure shows how the speeds of the first planet carrier, the first ring gear and the first sun gear of the differential planetary gear system change with wind speed. It can be seen that based on the speed regulation of the differential speed regulating device, as the wind speed increases, the speeds of the first planet carrier and the first ring gear will first gradually increase and then eventually stabilize, and the speed of the first sun gear is constant and is not affected by the wind speed.

[0163] Figure 8The example shows the changes of the speed and power of the permanent magnet motor with wind speed. It can be seen that based on the speed regulation of the differential speed control device, as the wind speed increases, the speed of the permanent magnet motor will first gradually increase and then eventually stabilize, and the power of the permanent magnet motor will change from positive to negative and then eventually stabilize.

[0164] Fig. 9 The example shows how the speed and power of the speed regulating motor change with wind speed. It can be seen that based on the speed regulation of the differential speed regulating device, as the wind speed increases, the speed of the speed regulating motor will change from negative to positive, gradually increase and finally stabilize, and the power of the permanent magnet motor will change from positive to negative and then finally stabilize.

[0165] Fig.10 The example shows how the speed and power of the first gear ring change with wind speed. It can be seen that based on the speed regulation of the differential speed control device, as the wind speed increases, the speed of the first gear ring will change from negative to positive, gradually increase and finally stabilize, and the power of the first gear ring will change from positive to negative and then finally stabilize.

[0166] The first gear ring requires a low speed and a large torque. When the magnetic load and the electric load are constant, the structural size of the motor is proportional to the torque. In order to reduce the structural size of the speed regulating motor, a quasi-planetary gear train is set between the speed regulating motor and the first gear ring; in particular, the quasi-planetary gear train uses a double-linked planetary gear, one group is meshed with the second gear ring, and the other group is meshed with the second sun gear, and the second sun gear is connected to the rotor of the speed regulating motor. The quasi-planetary gear train can also use only one group of planetary gears, which are meshed with the second gear ring and the second sun gear at the same time. The final matching is specifically required according to the speed between the speed regulating motor and the first gear ring. At the same time, the quasi-planetary gear train has a compact structure and a small size, which is very suitable for the needs of the narrow space in the cabin of the wind turbine generator.

[0167] Fig.11 The electrically excited synchronous generator ( Fig.11 From the changes in speed and power of the electrically excited synchronous generator (referred to as the synchronous motor) with wind speed, it can be seen that based on the speed regulation of the differential speed control device, as the wind speed increases, the speed of the electrically excited synchronous generator remains constant and is not affected by the wind speed, and the power of the electrically excited synchronous generator will gradually increase and then eventually stabilize.

[0168] Example 3

[0169] This embodiment provides a control method for a differential speed regulating device. The control method is implemented based on the differential speed regulating device in Embodiment 1. Fig.12 As shown, the control method includes:

[0170] S1. Obtain a second preset rotation speed and a first real-time rotation speed.

[0171] S2. Determine whether the first real-time rotation speed is higher than the second preset rotation speed.

[0172] If it is higher, then execute step S3, if it is lower, then execute step S4;

[0173] S3. Control the first planetary gear to drive the first ring gear to rotate.

[0174] S4. Control the first ring gear to drive the first planetary gear to rotate.

[0175] The wind turbine generator set includes an electrically excited synchronous generator, and the differential speed regulating device includes a permanent magnet motor, a differential planetary gear train, a quasi-planetary gear train and a speed regulating motor; the differential planetary gear train includes a first sun gear, a first planetary gear, a first planet carrier and a first ring gear, and the quasi-planetary gear train includes a second sun gear, a second planetary gear and a second ring gear. The rotor of the permanent magnet motor is coaxially fixedly connected to the first planet carrier, the rotor of the speed regulating motor is coaxially fixedly connected to the second sun gear, the first ring gear and the second ring gear are coaxially fixedly connected, and the first sun gear is connected to the electrically excited synchronous generator through a first coupling; the first planet carrier rotates based on a first real-time speed and transmits the first real-time speed to the first planetary gear; the first ring gear rotates based on a second real-time speed and transmits the second real-time speed to the first planetary gear; the first planetary gear synthesizes a first preset speed corresponding to the first sun gear based on the first real-time speed and the second real-time speed, and the first sun gear outputs the first preset speed to the electrically excited synchronous generator to drive the electrically excited synchronous generator to operate.

[0176] When the first real-time rotation speed is lower than the second preset rotation speed, the first ring gear is used to drive the first planetary gear to rotate, so that the permanent magnet motor is in a power generation mode and the speed regulating motor is in a motoring mode;

[0177] When the first real-time speed is higher than the second preset speed, the first planetary gear is used to drive the first ring gear to rotate, so that the permanent magnet motor is in the electric mode and the speed regulating motor is in the power generation mode;

[0178] The second preset speed is determined based on the number of teeth of the first sun gear, the number of teeth of the first ring gear and the first preset speed.

[0179] Specifically, when the first real-time speed is lower than the second preset speed, the first ring gear needs to obtain power from the outside to rotate the first planetary gear to ensure that the first sun gear outputs the first preset speed constantly. At this time, the permanent magnet motor is in the power generation mode and the speed regulating motor is in the electric mode. When the first real-time speed is higher than the second preset speed, the first ring gear needs to output power to the outside to make the first planetary gear drive the first ring gear to rotate to ensure that the first sun gear outputs the first preset speed constantly. At this time, the permanent magnet motor is in the electric mode and the speed regulating motor is in the power generation mode.

[0180] The working principle of the differential speed regulating device disclosed in the present invention has been described in detail in Example 1, and will not be repeated here.

[0181] The control method of the differential speed regulating device of this embodiment is implemented based on the differential speed regulating device in Example 1. No matter whether the first real-time speed input to the first planetary carrier is higher or lower, the first sun gear can stably output the first preset speed to the electrically excited synchronous generator to drive the electrically excited synchronous generator to operate at a constant speed. The differential speed regulating device realizes variable speed input, self-powered speed regulation, and constant speed output. The overall structure is compact, small in size, and light in weight. The wind turbine generator set does not need to draw electricity from the power grid and can be started in the dark. The electrically excited synchronous generator is directly connected to the grid, and the power grid supporting capacity is strong.

[0182] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A differential speed regulating device, applied to a wind turbine generator set, characterized in that: The wind turbine generator set includes an electrically excited synchronous generator, and the differential speed regulating device includes a permanent magnet motor, a differential planetary gear train, a quasi-planetary gear train and a speed regulating motor; The rotor of the permanent magnet motor is connected to the differential planetary gear train, the rotor of the speed regulating motor is connected to the quasi-planetary gear train, and the differential planetary gear train is connected to the quasi-planetary gear train and drives each other; The differential planetary gear train is connected to the rotor of the electrically excited synchronous generator and drives the rotor of the electrically excited synchronous generator to operate at a first preset speed.

2. The differential speed regulating device according to claim 1, characterized in that: The wind turbine generator set further comprises a first coupling; The differential planetary gear train comprises a first sun gear, a first planet gear, a first planet carrier and a first ring gear; the first sun gear and the first planet gear are both located in the first ring gear, and the first planet gear is meshed with the inner teeth of the first ring gear and the first sun gear at the same time; The quasi-planetary gear train comprises a second sun gear, a second planetary gear and a second ring gear; the second sun gear and the second planetary gear are both located in the second ring gear, and the second planetary gear is meshed with the inner teeth of the second ring gear and the second sun gear at the same time; The rotor of the permanent magnet motor is coaxially fixedly connected to the first planet carrier, the rotor of the speed regulating motor is coaxially fixedly connected to the second sun gear, the first ring gear and the second ring gear are coaxially fixedly connected, and the first sun gear is connected to the electrically excited synchronous generator through the first coupling to drive the electrically excited synchronous generator to operate.

3. The differential speed regulating device according to claim 2, characterized in that: The wind turbine generator set further comprises a wind rotor, the first planet carrier rotates based on a first real-time rotation speed and transmits the first real-time rotation speed to the first planetary wheel, and the first real-time rotation speed is related to the rotation speed of the wind rotor; The first ring gear rotates based on a second real-time rotation speed and transmits the second real-time rotation speed to the first planetary gear, wherein the second real-time rotation speed is related to the rotor rotation speed of the speed regulating motor; The first planetary gear synthesizes the first preset speed corresponding to the first sun gear based on the first real-time speed and the second real-time speed, and the first sun gear outputs the first preset speed to the rotor of the electrically excited synchronous generator to drive the rotor of the electrically excited synchronous generator to operate.

4. The differential speed regulating device according to claim 3, characterized in that: When the first real-time speed is lower than the second preset speed, the permanent magnet motor is in a power generation mode, the speed regulating motor is in an electric mode, and the first ring gear is used to drive the first planetary gear to rotate; When the first real-time speed is higher than the second preset speed, the permanent magnet motor is in the electric mode, the speed regulating motor is in the power generation mode, and the first planetary gear is used to drive the first ring gear to rotate; The second preset speed is determined based on the number of teeth of the first sun gear, the number of teeth of the first ring gear, and the first preset speed.

5. The differential speed regulating device according to claim 4, characterized in that: When the external wind speed is less than or equal to the preset wind speed, the first real-time rotation speed is lower than the second preset rotation speed; When the external wind speed is greater than the preset wind speed, the first real-time rotation speed is lower than the second preset rotation speed.

6. The differential speed regulating device according to claim 2, characterized in that: The first coupling is a flexible coupling; And / or, the quasi-planetary gear train further includes a third planetary gear, and the second planetary gear and the third planetary gear are coaxially fixedly connected.

7. The differential speed regulating device according to claim 1, characterized in that: The wind turbine generator set further comprises a multi-port converter, through which the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator are respectively electrically connected; The multi-port converter is configured to provide a DC excitation current to a rotor of the electrically excited synchronous generator to generate a magnetic field; The multi-port converter is further configured to transfer the electric energy output by the permanent magnet motor to the speed regulating motor based on the current wind rotor speed, so as to drive the speed regulating motor to operate at a corresponding speed; Or the electric energy output by the speed regulating motor is transmitted to the permanent magnet motor to drive the permanent magnet motor to operate at a corresponding speed.

8. A wind turbine generator set, characterized in that: The wind turbine generator set comprises a differential speed regulating device as claimed in any one of claims 1 to 7.

9. The wind turbine generator set according to claim 8, characterized in that: The wind turbine generator set also includes a multi-port converter and an electrically excited synchronous generator; The multi-port converter is electrically connected to the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator respectively, and is used to receive corresponding control signals to drive the permanent magnet motor, the speed regulating motor and the electrically excited synchronous generator to operate respectively.

10. The wind turbine generator set according to claim 8, characterized in that: The wind turbine generator set also includes a wind wheel, a main gear box, a second coupling and a high-speed shaft brake component; The input end of the main gearbox is coaxially fixedly connected to the wind wheel, and the output end of the main gearbox is connected to the permanent magnet motor through the second coupling; The main gearbox is used to increase the speed of the wind wheel of the wind wheel to a first real-time speed, and input the first real-time speed to the first planet carrier of the differential planetary gear train; The high-speed shaft brake component is arranged at the output end of the main gear box, and the high-speed shaft brake component is used to stop the wind wheel.

11. The wind turbine generator set according to claim 10, characterized in that: The second coupling is a flexible coupling.

12. The wind turbine generator set according to claim 9, characterized in that: The wind turbine generator set further comprises a grid-connected switch, which is used to control the on-off between the electrically excited synchronous generator and the power grid; And / or, the wind turbine generator set further includes a controller, and the controller is used to send the control signal to the multi-port converter.

13. A control method for a differential speed regulating device, characterized in that: The control method is implemented based on the differential speed regulating device according to any one of claims 1 to 7; the control method comprises: Acquire a second preset speed and a first real-time speed; Determining whether the first real-time speed is higher than the second preset speed; If it is higher, the permanent magnet motor is controlled to be in electric mode, and the speed regulating motor is controlled to be in power generation mode; If it is lower than, the permanent magnet motor is controlled to be in the power generation mode, and the speed regulating motor is controlled to be in the electric mode.

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