CN1976178B - Variable speed constant frequency excitation control system - Google Patents

Abstract

A variable-speed constant-frequency excitation control system relates to an excitation control system with a series permanent magnet variable-speed constant-frequency excitation double-rotor wind power generator. Among them, the exciter is coaxially installed in series with the main drive shaft of the main wind wheel of the device and the main body of the generator; the permanent magnet outer rotor is in a structure of relative rotation with the inner rotor of the exciter, and the permanent magnet outer rotor rotates relative to the generator stator The structure is set; the auxiliary wind wheel is a structure that can drive the permanent magnet outer rotor and is installed on the auxiliary transmission shaft; the auxiliary transmission shaft driven by the auxiliary wind wheel and the main transmission shaft driven by the main wind wheel can rotate mutually The above-mentioned main and auxiliary wind wheels are equipped with a main wind wheel speed measurement device and an auxiliary wind wheel speed measurement device that can transmit the speed signal to the centralized control device of the unit; the present invention does not need to configure power converters with complex power The device effectively simplifies the structure of the unit, improves the operating efficiency and reliability of the unit, and reduces the cost of the control system.

Description

Variable speed constant frequency excitation control system

technical field

The invention relates to a wind power generator, in particular to a series permanent magnet variable-speed constant-frequency excitation double-rotor wind power generator and an excitation control system with the wind power generator.

Background technique

Known technology such as Chinese patent CN200510022771.1 discloses a variable-speed constant-frequency method for wind power generation, which is characterized in that first, the speed of the wind turbine rotor is increased through the speed-increasing gearbox, and then the input power generated by the variable speed is input into the differential The input shaft of the permanent magnet motor is divided or merged by the differential mechanism of the differential permanent magnet motor to generate power flow into the stator winding of the differential permanent magnet motor through the feeder to realize constant speed and constant frequency power generation to the power grid, so as to improve the power generation system. power generation efficiency.

Another example is Chinese patent CN200410003089.3 which discloses a MW level direct drive permanent magnet outer rotor synchronous wind generator, which adopts a multi-pole outer rotor structure. The generator includes a fixed shaft, a rotating shaft, a coil winding, a permanent magnetic steel, an iron core, a stator and an outer rotor, wherein the rotating shaft is mounted on the fixed shaft through a bearing, the stator is mounted on the fixed shaft through a stator bracket, and the outer rotor passes through The rotor support is installed on the rotating shaft, and an axial cooling ventilation channel may be provided between the winding coil and the stator support; a protective cover is provided on the windward surface between the outer rotor and the stator. Due to the large number of poles, the speed is very low, so there is no need for a speed-increasing gearbox, and it can be directly driven to generate electricity; the generator does not have its own cooling fan or external cooling system.

It is known that wind turbines transmit the power generated by the wind wheel under the action of wind to the generator through the gearbox and make it obtain a corresponding speed; usually the speed of the wind wheel is very low, which is far below the requirements for high-speed generator power generation. The speed must be realized through the speed-up effect of the gear pair of the gearbox; while the working conditions of the wind turbine unit are generally very poor, frequent failures of the gearbox are common.

Products manufactured by known technologies have poor reliability, high maintenance costs, and low unit efficiency. The industry hopes to take advantage of the brushless structure of the brushless doubly-fed motor technology and the wide range of variable speed and constant frequency operation, combined with the technical advantages of efficient use of wind energy by the double phoenix wheels installed on the dual rotor drive shafts that rotate in opposite directions to each other, and remove the gearbox and The complex control system realizes the variable speed and constant frequency operation of the generating set.

Contents of the invention

The problem to be solved by the present invention is to provide an excitation control system for a variable-speed constant-frequency wind motor by overcoming the above-mentioned defects in the conventional technology.

The present invention solves the technical problem of the dual-rotor variable-speed constant-frequency wind motor by adopting the following technical solutions. According to the present invention, a dual-rotor variable-speed constant-frequency wind motor includes the generator stator in the main body of the generator and the main drive shaft Transmission, the rotor of the generator set in a rotating structure relative to the stator, wherein the exciter is coaxially installed in series with the main drive shaft of the main wind wheel of the device and the main body of the generator; the permanent magnet is arranged on the yoke of the permanent magnet outer rotor to form an excitation The permanent magnet outer rotor of the generator; the permanent magnet outer rotor is in a structure that rotates relative to the exciter inner rotor, and the permanent magnet outer rotor is in a structure that rotates relative to the generator stator; the auxiliary wind wheel is in the form of a driveable permanent magnet The structure of the outer rotor is installed on the auxiliary transmission shaft; the auxiliary transmission shaft driven by the auxiliary wind wheel and the main transmission shaft driven by the main wind wheel are coaxially connected in a mutually rotatable manner.

In this case, the solution to the technical problem of the dual-rotor variable-speed constant-frequency wind motor can be further realized by the following technical measures:

The aforementioned dual-rotor variable-speed constant-frequency wind motor, wherein, the auxiliary wind wheel is configured in a transmission structure that rotates in opposite directions relative to the main wind wheel; the auxiliary wind wheel is arranged in an upwind direction; Rotation structure set.

In the aforementioned dual-rotor variable-speed constant-frequency wind motor, the permanent magnets are arranged in groups, and the number of pole pairs matches the number of pole pairs of the inner rotor of the exciter; the yoke of the permanent magnet of the device is arranged in the permanent magnet outer rotor housing.

In the aforementioned dual-rotor variable-speed constant-frequency wind generator, there is a preset distance between the auxiliary wind rotor and the exciter to avoid collision between the auxiliary wind rotor and the tower.

In the aforementioned dual-rotor variable-speed constant-frequency wind generator, the main and auxiliary transmission shafts each have hollow through holes with preset diameters, and the transmission shafts are supported by bearings arranged on the generator and the exciter.

In this case, the following technical measures can be used to solve the technical problems of the variable-speed constant-frequency excitation control system. According to the present invention, a variable-speed constant-frequency excitation control system includes a generator. The generator has a generator stator and is driven by a main drive shaft, The generator rotor is arranged in a rotating structure relative to the stator, wherein the exciter is coaxially installed in series with the generator main body through the main drive shaft of the main wind wheel; the permanent magnet is set on the yoke of the permanent magnet outer rotor to form the permanent Magnetic outer rotor; the permanent magnet outer rotor is configured to rotate relative to the exciter inner rotor, and the permanent magnet outer rotor is configured to rotate relative to the generator stator; the auxiliary wind wheel is a structural device that can drive the permanent magnet outer rotor On the auxiliary transmission shaft: the auxiliary transmission shaft driven by the auxiliary wind wheel and the main transmission shaft driven by the main wind wheel are coaxially connected in a mutually rotatable manner.

In this case, to solve the technical problems of the variable-speed constant-frequency excitation control system, the following technical measures can be adopted to further realize:

The aforementioned variable-speed constant-frequency excitation control system, wherein, the auxiliary wind rotor is configured in a transmission structure that rotates in opposite directions relative to the main wind rotor; the auxiliary wind rotor is configured to rotate in an upwind direction; the main wind rotor rotates in a downwind direction structure settings.

In the aforementioned variable-speed constant-frequency excitation control system, the permanent magnets are arranged in groups, and the number of pole pairs matches the number of pole pairs of the inner rotor of the exciter; the yoke of the permanent magnet of the device is arranged in the permanent magnet outer rotor housing.

In the aforementioned variable-speed constant-frequency excitation control system, there is a preset distance between the auxiliary wind rotor and the exciter to avoid collision between the auxiliary wind rotor and the tower.

In the aforementioned variable-speed constant-frequency excitation control system, the main and auxiliary drive shafts each have hollow through holes with preset diameters, and the drive shafts are supported by bearings arranged on the generator and the exciter.

The aforementioned variable speed constant frequency excitation control system, wherein, the aforementioned main and auxiliary wind wheels are provided with a main wind wheel speed measuring device and an auxiliary wind wheel speed measuring device that can transmit the signal of the speed to the unit centralized control device; the unit centralized control device has The port connected with the wind speed detection device, the port connected with the wind direction detection device, and the port for data transmission with the upper computer; the yaw controller and the centralized control device of the unit are connected in a way to control the rotation of the main wind wheel in the downwind direction; the main wind The wind wheel and the auxiliary wind wheel are respectively equipped with the main wind wheel pitch adjustment mechanism and the auxiliary wind wheel pitch adjustment mechanism to adjust the pitch angle. The main and auxiliary wind wheel pitch adjustment mechanisms and the centralized control device of the unit are all based on The method of controlling the pitch of the wind turbine pitch adjustment mechanism is connected; the voltage output terminal of the generator is sequentially connected to a grid-connected control device that can limit the output voltage of the generator, softly connect to the grid after the same period, and softly split when it is shut down. Transformer, and then connected to the external power grid; between the grid-connected control device and the step-up transformer, an output voltage measurement device connected to the centralized control device of the unit, an output current detection device connected to the centralized control device of the unit, and a centralized The power grid frequency detection device connected with the control device; the no-load detection device connected with the centralized control device of the unit is arranged between the generator and the grid-connected control device.

The aforementioned variable-speed constant-frequency excitation control system, wherein: the secondary wind rotor of the generator is configured in a transmission structure that rotates in opposite directions relative to the main wind rotor; the main wind rotor is configured to rotate in the downwind direction; the blades of the main wind The wind area is set to 2-5 times the sweeping area of the blades of the auxiliary wind rotor; the structure of the main and auxiliary wind rotor pitch adjustment mechanisms is the same, and it is composed of a pitch servo mechanism and a pitch control device. The device is connected with the pitch servo mechanism through the pitch control device in such a way that the speed of the main wind wheel and the auxiliary wind wheel is adjusted according to the detected pitch angle change; the main wind wheel and the auxiliary wind wheel are respectively equipped with the main wind Wheel pitch angle measuring device, auxiliary wind rotor pitch angle measuring device.

The aforementioned variable speed constant frequency excitation control system, wherein: the permanent magnets of the generator are arranged in groups, and the number of pole pairs matches the number of pole pairs of the inner rotor of the exciter; the yoke of the permanent magnet of the device is arranged on the permanent magnet outer rotor Inside the casing; the pitch adjustment mechanism of the main and auxiliary wind rotors is driven by a servo motor; the pitch servo mechanism and the centralized control device of the unit form an electrical system that can adjust the speed of the main wind rotor and the auxiliary wind rotor according to the change of the pitch angle. coupling.

The aforementioned variable-speed constant-frequency excitation control system, wherein: the swept area of the blades of the main wind rotor of the generator is about three times the swept area of the blades of the auxiliary wind rotor, and the swept area is the area formed by the rotation of the wind rotor The main wind rotor rotates in the downwind direction, and the auxiliary wind rotor rotates in the upwind direction in the opposite direction; there is a preset distance between the auxiliary wind rotor and the exciter to avoid the collision between the auxiliary wind rotor and the tower; the centralized control of the brake and the unit The device is electrically connected in an electrical way that can start to work when the secondary wind rotor speed is 0.

The aforementioned variable-speed constant-frequency excitation control system, wherein: the number of pole pairs Pg of the stator winding is set to be greater than the number of pole pairs Pe of the permanent magnet outer rotor, and the main wind wheel arranged on the main drive shaft has a relative The stator with Pg pole pairs rotates at Nzr speed, and the speed of the main wind rotor satisfies the following relational configuration:

$\mathrm{<span\; class="notranslate">\; Nzr</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; fg</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; fe</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; Pg</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; Pe</span>}}$

Among them: Nzr indicates the speed of the main wind rotor; Pg indicates the number of pole pairs of the stator winding; Pe indicates the number of pole pairs of the permanent magnet outer rotor; fg indicates the frequency of the stator; fe indicates the converted frequency of the permanent magnet outer rotor;

The number of pole pairs of the stator winding is 3 times the number of pole pairs of the permanent magnet outer rotor; the number of pole pairs of the inner rotor winding of the exciter is set as the pair of poles of Pe; the number of pole pairs of the generator rotor winding is set as the number of pairs of poles of Pg; The inner rotor winding of the exciter and the rotor winding of the generator are connected in reverse phase sequence through the connection line between the rotors; the auxiliary wind wheel of the generator is arranged on the auxiliary transmission shaft, and the auxiliary wind wheel drives the permanent magnet outer rotor to rotate at Ne speed, And the converted frequency of the permanent magnet outer rotor satisfies the following relationship:

$\mathrm{fe}=\frac{\mathrm{Ne}\&times;\mathrm{Pe}}{60}$ Among them: Ne represents the relative speed of the auxiliary wind wheel to the stator;

A permanent magnet outer rotor with a Pe pole logarithm is arranged on the auxiliary drive shaft to rotate in reverse with respect to the main wind wheel at the speed of Nzre. The rotational speed of the permanent magnet outer rotor relative to the inner rotor of the exciter satisfies the following relationship:

Nzre=Nzr+Ne

Wherein: Nzre represents the rotating speed of the permanent magnet outer rotor relative to the exciter inner rotor; the main and auxiliary transmission shafts have hollow through holes with preset diameters, and the transmission shafts are configured by the bearings on the generator and the exciter. Bearing support.

Compared with the prior art, the present invention has significant advantages and beneficial effects. It can be seen from the above technical solutions that the present invention has at least the following advantages under the excellent structural configuration:

The present invention does not need to configure a power converter with complex power, effectively simplifies the structure of the unit, improves the operating efficiency and reliability of the unit, and reduces the cost of the control system. There is a slight increase, but the larger wind rotor is used to generate electricity, and the smaller wind rotor adjusts the excitation frequency and generates electricity, which effectively improves the utilization rate of wind energy, which is 10%-15% higher than that of conventional single-wheel wind turbines. ;

This case adopts the double-rotor structure of the brushless double-fed motor rotor and the rotating permanent magnet outer rotor to realize the variable-speed constant-frequency excitation operation of the unit, which is equivalent to reducing the number of pole pairs of a single-rotor generator with the same capacity by at least 1/3, thereby shortening the diameter of the generator and facilitating equipment. Transport and reduce the weight of the unit; the configuration of the double wind rotor structure and the configuration of the yaw mechanism in this case make the yaw control of the unit simpler and more reliable;

The unit in this case can realize variable speed constant frequency operation and variable pitch adjustment. The double wind turbine generator set in this case has greatly improved wind energy utilization rate compared with single wind turbine variable speed constant frequency unit. It has no gearbox, can realize direct drive, and has no slippage. There is no need for large-capacity converters, and the reliability of the unit is greatly improved; compared with the prior art, the present invention has significant contributions and progress, and is indeed a novel, creative, and practical good technology.

The specific embodiment of the present invention is given in detail by the following examples and accompanying drawings.

Description of drawings

Fig. 1 is a structural schematic diagram of a wind motor in the present invention;

Fig. 2 is a schematic diagram of the field winding wiring structure of the present invention;

Fig. 3 is a structural schematic diagram of the variable-speed constant-frequency excitation control system of the present invention;

Fig. 4 is a working principle block diagram of the variable-speed constant-frequency excitation control system of the present invention.

Detailed ways

The specific implementation, structure, features and effects provided by the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

As shown in Figures 1-4, a double-rotor variable-speed constant-frequency generator M includes a generator body 1 fixed on a base 10, a generator stator 16 fixed in a motor casing 111, and a generator rotor 14 passing through The main transmission shaft 13 is arranged in a structure that rotates relative to the stator 16, and 11 is the casing of the generator unit, wherein,

The exciter 4 is coaxially installed in the casing through the main transmission shaft and the main body of the generator; the permanent magnet 43 is installed on the yoke 42 in the permanent magnet outer rotor housing 410 to form the permanent magnet outer rotor 41 of the exciter. The permanent magnet outer rotor is set in a structure that is relatively rotating with the exciter inner rotor 45 through the connecting piece 46; the permanent magnets 43 are arranged in groups according to the known technology, and the number of pole pairs is the same as the number of pole pairs of the exciter inner rotor. Matching; the permanent magnet outer rotor is configured to rotate relative to the inner rotor of the exciter and rotate relative to the stator of the generator;

The auxiliary drive shaft 12 is coaxially connected with the main drive shaft 13; the main and auxiliary drive shafts have a hollow through hole 130 with a preset diameter, so that the transmission shaft of a large generator set is lighter in weight under the condition of meeting the technical requirements, thereby To reduce the weight of the body, the transmission shaft is supported by the bearings 115, 116 arranged on the generator and the bearings 147, 148 on the exciter; thus, the generator rotor and the inner rotor of the exciter coaxial with the rotor form a generator The tandem rotor structure and the permanent magnet outer rotor form a double-rotor structure, so that the unit can achieve variable speed and constant frequency operation, which is equivalent to reducing the number of pole pairs of a single-rotor generator with the same capacity by at least 1/3, so the diameter of the generator can be shortened, and further Reduce the weight of the motor;

Through the known technology, the auxiliary transmission shaft 12 driven by the auxiliary wind wheel and the main transmission shaft 13 driven by the main wind wheel are coaxially installed in a mutually rotatable connection mode, and the power of the auxiliary wind wheel is transferred by the auxiliary transmission shaft. transmitted to the permanent magnet outer rotor;

The auxiliary wind wheel 2 is installed in the shaft body end of the auxiliary drive shaft 12 in the opposite direction relative to the main wind wheel. The auxiliary wind wheel is installed in the upwind direction of the F2 direction through its hub 21 according to the known technology. The auxiliary wind wheel and the excitation There is a preset distance L between the wind turbines to avoid the collision between the auxiliary wind rotor and the tower, and the reserved distance between the auxiliary wind rotor and the tower can be determined by the elevation angle of the main wind rotor; the main wind rotor 3 is assembled on the main drive At the end of the shaft 13, the main wind wheel is arranged in a leeward rotation structure in the direction of F3 through its hub 31 with known technology.

A variable-speed constant-frequency excitation control system, including the aforementioned wind motor M, wherein the main wind wheel 3 of the wind motor is arranged on the main transmission shaft, and rotates at Nzr speed relative to the stator 16 with Pg pole logarithm under the action of wind force, And the speed of the main wind rotor satisfies the following relationship:

$\mathrm{<span\; class="notranslate">\; Nzr</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; fg</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; fe</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; Pg</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; Pe</span>}}$

Among them: Nzr represents the speed of the main wind rotor; Pg represents the number of pole pairs of the stator winding; Pe represents the number of pole pairs of the permanent magnet outer rotor 41; fg represents the frequency of the stator; fe represents the converted frequency of the permanent magnet external rotor;

The number of pole pairs of the windings of the inner rotor 45 of the exciter is set to be the opposite poles of Pe; the number of pole pairs of the windings of the generator rotor 14 is set to be the pair of poles of Pg; the inner rotor windings of the exciter and the generator rotor windings are connected through the rotor Line 123 is connected in anti-phase sequence;

The number of pole pairs Pg of the stator winding is set to be greater than the number of pole pairs of the permanent magnet outer rotor Pe, and the number of pole pairs of the stator winding can be 3 times the number of pole pairs of the permanent magnet outer rotor;

The auxiliary wind rotor 2 of the wind generator is arranged on the auxiliary transmission shaft, and the auxiliary wind rotor drives the permanent magnet outer rotor to rotate in the opposite direction relative to the main wind rotor at Ne speed, and the converted frequency of the permanent magnet outer rotor satisfies the following relationship:

$\mathrm{<span\; class="notranslate">\; fe</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Ne</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; Pe</span>}}{\mathrm{<span\; class="notranslate">\; 60</span>}}$

Among them: Ne represents the relative speed of the auxiliary wind wheel to the stator

A permanent magnet outer rotor with a Pe pole logarithm that rotates relatively at the Nzre speed is arranged on the auxiliary drive shaft. The rotational speed of the permanent magnet outer rotor relative to the exciter inner rotor satisfies the following relationship:

Nzre=Nzr+Ne

Among them: Nzre represents the rotation speed of the permanent magnet outer rotor relative to the inner rotor of the exciter;

The above-mentioned main and auxiliary wind wheels are provided with the main wind wheel speed measuring device G and the auxiliary wind wheel speed measuring device G1, which can transmit the signal of the speed to the unit centralized control device 5, and the wind speed measured through the port D1 connected to the wind speed detection device and the wind rotor speed measured by the speed measuring device are transmitted to the unit centralized control device 5; the unit centralized control device is connected with the yaw controller 6 to control the downwind rotation of the main wind rotor, and the yaw controller 6 can be installed under the base the cabin interior 101;

The hub parts of the main wind rotor and the auxiliary wind rotor are respectively equipped with a main wind rotor pitch adjustment mechanism 38 and an auxiliary wind rotor pitch adjustment mechanism 28 for adjusting the pitch angle. The pitch adjustment mechanism is electrically connected with the unit centralized control device 5, and the unit centralized control device 5 issues a pitch change command to the main wind rotor pitch adjustment mechanism 38; the auxiliary wind rotor and the main wind rotor are respectively equipped with auxiliary wind rotor paddles Pitch angle measurement device G28, main wind rotor pitch angle measurement device G38;

The main and auxiliary wind wheel pitch adjustment mechanisms have the same structure, which consists of pitch servo mechanisms 381, 281 driven by servo motors M38, M28 and pitch control devices 382, 282. The pitch control devices 382, 282 are connected with the pitch servo mechanisms 381, 281 driven by the servo motors M38, M28; the pitch servo mechanisms are controlled by the unit centralized control device 5 according to the detected changes in the pitch angle of the main wind rotor. and the speed adjustment of the auxiliary wind rotor to realize the downwind rotation of the main wind rotor, while the upwind direction of the auxiliary wind rotor rotates in the opposite direction; the brake 15 is arranged between the generator end cover and the hub of the auxiliary wind rotor;

Connect the grid-connected control device 7 and the step-up transformer 8 in sequence at the voltage output end of the generator, and then connect with the external power grid W; between the grid-connected control device and the step-up transformer, arrange in turn a power grid connected with the unit centralized control device 5 The output voltage measurement device G4, the output current detection device G3 connected with the unit centralized control device, and the grid frequency detection device G2 connected with the unit centralized control device; the unit centralized control device is arranged between the generator M and the grid-connected control device The connected no-load detection device G5; the unit centralized control device also has a port D1 connected with the wind speed detection device (not shown), a port D2 connected with the wind direction detection device (not shown), and a port D3 for data transmission with the upper computer The main and auxiliary wind rotor blades are installed on the wind rotor hub in a known technical manner, and the sweeping area of the main wind rotor blades is 2-5 times greater than the blade sweeping area of the auxiliary wind rotors, especially the main wind rotor blades The sweeping area is preferably about 3 times the sweeping area of the blades of the auxiliary wind rotor, and the sweeping area is the area formed by the rotation of the wind rotor;

The output current of the generator measured by the output current detection device G3 and the output voltage of the generator measured by the output voltage measurement device G4 are transmitted to the unit centralized control device 5, and the output power of the generator calculated by the unit centralized control device 5 is The value is compared with the preset rated power value; under the set conditions, the unit centralized control device 5 collects the wind speed measured by the connection port D1 of the wind speed detection device and the rated speed of the main wind wheel measured by the speed measurement device G Calculate the adjustment value of the pitch angle of the rated speed of the main wind rotor at this wind speed, and then compare it with the pitch angle value collected by the main wind rotor pitch angle measuring device G38, and the 5 pairs of the main wind rotor change by the unit centralized control device The pitch adjustment mechanism 38 issues a pitch change command; thus, the main wind wheel can be operated at a constant power to prevent the generator from being overloaded;

When the series permanent-magnet variable-speed constant-frequency excitation double-rotor wind generator is connected to the grid and the speed of the main wind rotor is between the preset rated speed and the minimum speed, the auxiliary wind rotor is adjusted relative to the main wind turbine according to the preset conditions under the adjustment of the centralized control device 5 of the unit. The wind rotor rotates in the opposite direction, and the frequency of the stator voltage of the generator is always 50Hz through this speed change;

To sum up, in the wind turbine with double wind rotor mechanism, the main wind rotor with larger diameter is used for power generation, and the auxiliary wind rotor with smaller diameter is used for adjusting the excitation frequency and generating power. The two rotate on the same axis and in opposite directions. , the yaw controller is responsible for controlling the downwind rotation of the main wind rotor, the main power generation; the reverse rotation of the auxiliary wind rotor upwind direction, auxiliary power generation, greatly improving efficiency.

The configuration of the voltage output terminal grid-connected control device of the generator can limit the output voltage of the generator, soft grid-connected after the same period, and soft cracking when shutting down, which can effectively reduce the impact of grid-connected reactive current and ensure the safety of the unit running; when the generator reaches the rated output power, the unit power factor is controlled to run around cosθ=1; when the generator output active power is small, the unit outputs inductive reactive power with cosθ<1; when the generator speed is lower than the rated minimum When the speed or output power of the generator is higher than the maximum output power, the generator is disconnected from the grid, and the soft disconnection is completed through the configuration of the grid-connected control device.

Variable speed constant frequency excitation control method:

1. The main wind wheel 3 is arranged on the main drive shaft 13 to rotate at Nzr speed relative to the stator 16 with Pg pole logarithm under the action of wind force, and the speed of the main wind wheel satisfies the following relationship:

$\mathrm{<span\; class="notranslate">\; Nzr</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 60</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; fg</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; fe</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; Pg</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; Pe</span>}}$

Among them: Nzr represents the speed of the main wind rotor; Pg represents the number of pole pairs of the stator winding; Pe represents the number of pole pairs of the permanent magnet outer rotor 41; fg represents the frequency of the stator; fe represents the converted frequency of the permanent magnet external rotor;

2. The auxiliary wind wheel arranged at the end of the auxiliary drive shaft 12 drives the permanent magnet outer rotor to rotate in the opposite direction relative to the main wind wheel at Ne speed, and the converted frequency of the permanent magnet outer rotor satisfies the following relationship:

$\mathrm{fe}=\frac{\mathrm{Ne}\&times;\mathrm{Pe}}{60}$ Among them: Ne represents the relative speed of the auxiliary wind wheel to the stator

3. A permanent magnet outer rotor with a Pe pole logarithm that rotates at the speed of Nzre is arranged on the auxiliary transmission shaft. The rotational speed of the permanent magnet outer rotor relative to the excitation inner rotor satisfies the following relational formula: Nzre=Nzr+Ne

Among them: Nzre represents the rotation speed of the permanent magnet outer rotor relative to the inner rotor of the exciter

4. The number of pole pairs of the windings of the inner rotor 45 of the exciter is set as the opposite poles of Pe; the number of pole pairs of the windings of the generator rotor 14 is set as the pair of poles of Pg; the inner rotor windings of the exciter and the generator rotor windings pass through the rotor The connecting line 123 is connected in reverse phase sequence;

5. The wind speed measured by the port D1 connected with the wind speed detection device and the speed of the main wind rotor measured by the speed measurement device G are transmitted to the unit centralized control device 5. When the main wind rotor is lower than the rated speed, the unit centralized control device performs main control. The value of the tip speed ratio of the wind rotor is compared with the value of the tip speed ratio of the main wind rotor preset by the centralized control device of the unit, and the adjustment value of the pitch angle is calculated, and then compared with the main wind rotor pitch angle measurement device G38 The collected pitch angle values are compared, and the centralized control device 5 of the unit sends a pitch change command to the pitch adjustment mechanism 38 of the main wind rotor; thus, the main wind rotor can be operated at its optimum tip speed ratio below the rated speed , to achieve the purpose of making full use of wind energy;

When the main wind rotor reaches the rated speed, the output current of the generator measured by the output current detection device G3 and the output voltage of the generator measured by the output voltage measurement device G4 are transmitted to the unit centralized control device 5, and the unit centralized control The generator output power value calculated by the device is compared with the preset rated power value; when the preset value is met, the unit centralized control device 5 will collect the wind speed measured by the port D1 connected to the wind speed detection device and pass the speed measurement The rated rotational speed of the main wind rotor measured by the device G is used to calculate the adjustment value of the pitch angle of the rated rotational speed of the main wind rotor at this wind speed, and then compared with the pitch angle value collected by the main wind rotor pitch angle measuring device G38. The unit centralized control device 5 issues a pitch command to the main wind rotor pitch adjustment mechanism 38; thus, the main wind rotor can be operated at a constant power to prevent the generator from being overloaded;

6. The wind speed measured by the port D1 connected to the wind speed detection device, and the auxiliary wind rotor speed measured by the auxiliary wind rotor speed measuring device G1 are transmitted to the unit centralized control device 5; when the main wind rotor is lower than the rated speed, the unit The centralized control device 5 collects the frequency value of the grid frequency detection device G2 and compares it with the generator output voltage frequency value calculated at the speed of the auxiliary wind rotor, calculates the adjustment value of the pitch angle of the auxiliary wind rotor at this speed, and then compares it with the value of the auxiliary wind rotor. The pitch angle values collected by the wind rotor pitch angle measuring device G28 are compared, and the unit centralized control device 5 issues a pitch change command to the auxiliary wind rotor pitch adjustment mechanism 28; the unit centralized control device 5 according to $\mathrm{Nzr}=\frac{60\&times;(\mathrm{fg}-\mathrm{fe})}{\mathrm{Pg}+\mathrm{Pe}}$ Relational expression for variable speed control, so that the generator keeps running at a constant frequency of 50Hz below the rated speed; The rated speed of the wheel is transmitted to the unit centralized control device 5. When the main wind rotor reaches the rated speed, the unit centralized control device 5 collects the frequency value of the grid frequency detection device G2 and compares the value of the generator output voltage frequency calculated at the rated speed of the auxiliary wind rotor. , calculate the adjustment value of the pitch angle of the auxiliary wind rotor at this wind speed, and then compare it with the pitch angle value collected by the auxiliary wind rotor pitch angle measurement device G28, and adjust the pitch of the 5 pairs of auxiliary wind rotors in the unit centralized control device Mechanism 28 issues a pitch command; keeps the generator running at a constant frequency of 50 Hz at rated speed; takes the output voltage frequency of the generator as the adjustment target, and limits the stator frequency fg by adjusting the pitch angle of the auxiliary wind wheel to control the speed of the auxiliary wind wheel as 50Hz, the static fe of the permanent magnet outer rotor is regarded as 0;

7. The number of pole pairs Pg of the stator winding is set to be greater than the number of pole pairs Pe of the permanent magnet outer rotor, and the number of pole pairs of the stator winding can be three times the number of pole pairs of the permanent magnet outer rotor.

Therefore, the two rotor windings connected in series during operation have the same current frequency and rotating magnetic fields in opposite directions, and the rotation speed Nzre of the excitation magnetic field of the generator rotor winding relative to the series connection rotor is superimposed and coordinated with the mechanical rotation speed Nzr of the main wind rotor shaft, always forming Synchronous excitation magnetic field, the synchronous magnetic field generates a 50Hz potential in the stator winding with Pg opposite poles, realizing the variable speed constant frequency excitation operation of the generator set.

8. The main wind rotor assembled on the transmission shaft 13 and the auxiliary wind rotor 2 assembled on the auxiliary transmission shaft are arranged in relative reverse rotation through the relative opposite direction adjustment of the blade pitch angle.

9. When the speed of the main wind rotor is between the preset rated speed and the minimum speed, the auxiliary wind rotor rotates in the opposite direction according to the preset law under the adjustment of the centralized control device 5 of the unit, forming a change that keeps the generator stator voltage frequency at 50Hz all the time Rotational speed; when the speed of the main wind rotor reaches 1.2-1.5 times of the rated speed, and at the same time the speed of the auxiliary wind rotor reaches the minimum speed of 0 speed, the brake 15 starts; that is, when the speed of the main wind rotor reaches the rated minimum speed, the auxiliary wind rotor reverses The speed reaches the highest, and the unit can realize variable speed and constant frequency operation.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to within the scope of the technical solutions of the present invention.

Claims (10)

1. A variable-speed constant-frequency excitation control system, comprising a generator (M), the generator has a generator stator (16) and is driven by a main transmission shaft (13), and is a generator set in a rotating structure relative to the stator (16) The rotor (14) is characterized in that the exciter (4) is coaxially installed in series with the main drive shaft of the main wind wheel (3) of the device and the main body of the generator; the yoke (42) of the permanent magnet outer rotor is provided with a permanent magnet ( 43) The permanent magnet outer rotor (41) constituting the exciter; the permanent magnet outer rotor is configured to rotate relative to the exciter inner rotor (45), and the permanent magnet outer rotor is configured to rotate relative to the generator stator; The auxiliary wind wheel is installed on the auxiliary transmission shaft in a structure capable of driving the permanent magnet outer rotor; the auxiliary transmission shaft (12) driven by the auxiliary wind wheel and the main transmission shaft (13) driven by the main wind wheel can rotate mutually The way of coaxial connection; The main and auxiliary wind wheels are provided with a main wind wheel speed measurement device (G) and an auxiliary wind wheel speed measurement device (G1) that can transmit the signal of the speed to the unit centralized control device (5); The unit centralized control device has a port (D1) connected with the wind speed detection device, a port (D2) connected with the wind direction detection device, and a port (D3) for data transmission with the upper computer; The yaw controller (6) is connected with the unit centralized control device to control the downwind rotation of the main wind rotor; the main wind rotor and the auxiliary wind rotor are respectively equipped with a main wind rotor pitch adjustment mechanism for adjusting the pitch angle ( 38), the auxiliary wind rotor pitch adjustment mechanism (28), the main and auxiliary wind rotor pitch adjustment mechanisms and the unit centralized control device (5) are all in the form of controlling the wind rotor pitch adjustment mechanism to change the pitch coupling; The voltage output terminal of the generator is sequentially connected with a grid-connected control device (7) and a step-up transformer (8), which can limit the output voltage of the generator, softly connect to the grid after the synchronization, and softly split during shutdown, and then connect to the external power grid ; Between the grid-connected control device and the step-up transformer, the output voltage measuring device (G4) connected with the unit centralized control device, the output current detection device (G3) connected with the unit centralized control device, and the unit centralized control device are sequentially arranged. A connected grid frequency detection device (G2); a no-load detection device (G5) connected with the unit centralized control device is arranged between the generator (M) and the grid-connected control device; the auxiliary wind wheel (2) is relatively The transmission structure configuration of the main wind wheel rotates in reverse; the auxiliary wind wheel is arranged in an upwind rotating structure; the main wind wheel is arranged in a downwind rotating structure. 2. The variable-speed constant-frequency excitation control system as claimed in claim 1, characterized in that, the permanent magnets (43) are configured in groups, and the number of pole pairs matches the number of pole pairs of the inner rotor of the exciter; A yoke (42) of magnets (43) is disposed within a permanent magnet outer rotor housing (410). 3. The variable-speed constant-frequency excitation control system according to claim 2, characterized in that there is a preset distance (L) between the auxiliary wind rotor and the exciter to avoid collision between the auxiliary wind rotor and the tower. 4. The variable-speed constant-frequency excitation control system according to claim 3, characterized in that, said main and auxiliary transmission shafts all have hollow through holes (130) with preset diameters, and the main transmission shaft is arranged on the generator by Bearings (115, 116) and bearings (147, 148) on the exciter are supported. 5. The variable-speed constant-frequency excitation control system according to any one of claims 1-4, characterized in that the swept area of the blades of the main wind rotor is set to be 2-5 times the swept area of the blades of the auxiliary wind rotor. 6. The variable-speed constant-frequency excitation control system as claimed in claim 5, characterized in that: said main and auxiliary wind rotor pitch adjustment mechanisms have the same structure, and it is controlled by a pitch servo mechanism (381, 281) and a pitch control mechanism. device (382, 282), and the unit centralized control device adjusts the speed of the main wind rotor and the auxiliary wind rotor according to the detected pitch angle change through the pitch control device and the pitch servo mechanism (381, 281). coupling. 7. The variable speed constant frequency excitation control system according to claim 6, characterized in that: the main wind wheel and the auxiliary wind wheel are respectively equipped with a main wind wheel pitch angle measuring device (G38), an auxiliary wind wheel paddle Distance angle measuring device (G28). 8. The variable-speed constant-frequency excitation control system as claimed in claim 7, characterized in that the main and auxiliary wind wheel pitch adjustment mechanisms are driven by servo motors (M38, M28); the pitch servo mechanism and unit centralized control device It is electrically connected in such a way that the rotation speed of the main wind rotor and the auxiliary wind rotor can be adjusted according to the change of the pitch angle. 9. variable speed constant frequency excitation control system as claimed in claim 8, is characterized in that, the blade sweeping area of the main wind rotor of described generator (M) is about 3 times of the blade sweeping area of secondary wind wheel, so The sweeping area described above is the area formed by the rotation of the wind wheel; the brake (15) is connected with the centralized control device of the unit in an electrical manner that can start work when the secondary wind wheel speed is 0. 10. The variable-speed constant-frequency excitation control system as claimed in claim 9, wherein the number of pole pairs Pg of the stator winding is set to be greater than the number of pole pairs Pe of the permanent magnet outer rotor, and the main wind wheel arranged on the main transmission shaft (3), under the action of wind force, the stator (16) with Pg pole logarithm rotates at the speed of Nzr, and the speed of the main wind rotor satisfies the following relational configuration:

Among them: Nzr represents the speed of the main wind rotor; Pg represents the number of pole pairs of the stator winding; Pe represents the number of pole pairs of the permanent magnet outer rotor (41); fg represents the frequency of the stator; fe represents the converted frequency of the permanent magnet external rotor; The number of pole pairs of the stator winding is 3 times the number of pole pairs of the permanent magnet outer rotor; the number of pole pairs of the inner rotor (45) of the exciter is set as the pair of poles of Pe; the number of pole pairs of the generator rotor (14) winding It is set as Pg opposite poles; the inner rotor winding of the exciter and the rotor winding of the generator are connected in anti-phase sequence through the connecting wire (123) between the rotors; the auxiliary wind wheel (2) of the generator is arranged on the auxiliary drive shaft, and the auxiliary The wind wheel drives the permanent magnet outer rotor to rotate at Ne speed, and the converted frequency of the permanent magnet outer rotor satisfies the following relationship: $\mathrm{fe}=\frac{\mathrm{Ne}\&times;\mathrm{Pe}}{60}$ Among them: Ne represents the relative speed of the auxiliary wind wheel to the stator; A permanent magnet outer rotor with a Pe pole logarithm is arranged on the auxiliary drive shaft to rotate in reverse with respect to the main wind wheel at the speed of Nzre. The rotational speed of the permanent magnet outer rotor relative to the inner rotor of the exciter satisfies the following relationship: Nzre=Nzr+Ne Among them: Nzre represents the rotation speed of the permanent magnet outer rotor relative to the inner rotor of the exciter.

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