CN101404476A - Operation control method for parallel variable-speed constant-frequency wind generator set - Google Patents

Abstract

An operation control method of a synchronization variable speed constant frequency wind generating set includes the strategies of AYC, synchronization control, low wind speed ceiling capacity follow control and high wind speed constant power control which includes the AYC, the synchronization control, the low wind speed ceiling capacity follow control and the high wind speed constant power control. An anemoscope and a wind vane measure the wind speed and wind direction information to generate a yaw deviation signal; a yaw motor is driven to execute left and right yaw according to the yaw direction and angle and limit the yaw velocity and meanwhile, the steering turns of the engine room are measured with the help of cables winding around a sensor, so as to execute safe untwist action, thus ensuring that the wind generating set realizes quick, accurate and safe effect of the wind wheel against wind. All the control strategies cooperate in work from the start to synchronization power generation according to the requirement of the set and external conditions, so as to ensure the safe and efficient operation of the wind generating set.

Description

Operation control method for parallel variable-speed constant-frequency wind generator set

Technical field

The present invention relates to a kind of progress control method of grid type wind turbine generator, be suitable for the wind-powered electricity generation set grid-connection operation of various capacity types, belong to new forms of energy and automation field.

Background technology

Along with rapid economy development, the consumption of the energy increases year by year, and the conventional energy resource resource faces day by day exhausted awkward situation, presses for some cleanings, pollution-free, the new forms of energy that can give birth to.Wind energy is a kind of continuous forever energy of cleaning, and wind energy development has huge economy, society, the value of environmental protection and development prospect, and wind power technology has had great advance over nearly 20 years, and wind-powered electricity generation exploitation speedup in various energy developments is the fastest.China has abundant wind resource, the development of wind-powered electricity generation industry has good resource base, in energy savings, alleviate China Power situation in short supply, reduce long-term cost of electricity-generating, reduce aspects such as air pollution that using energy source causes and reduction of greenhouse gas discharge and contribute.

Although wind energy makes a kind of inexhaustible, nexhaustible regenerative resource because little, the poor stability of wind energy energy density, can not store, efficient is lower, makes wind generator system some specific questions all occur technically with in the management.The electric energy that wind generator system sent is not directly inserted electrical network if do not control, and is a kind of pollution to electrical network, and a harmonic wave to electrical network has contribution in most cases, and can influence the stability of partial electric grid operation.Therefore, control technology is one of wind turbine generator maximum core technology, is the key of wind generator system safe and highly efficient operation.

Though the wind-powered electricity generation industry development of China is rapid, developed country compares with wind-powered electricity generation, has big gap aspect wind-driven generator manufacturing technology and wind power generation control technology.Awaiting further research and using aspect the advanced wind power technologies such as the maximization of blower fan, deliberate speed loss control, variable pitch control, variable speed constant frequency, the design production technology of variable pitch unit and variable speed constant frequency controller is still in the technological development stage.

Summary of the invention

Technical problem: the control method that the purpose of this invention is to provide a kind of grid type speed-variable frequency-constant wind-driven generator group, controlling schemes is divided into active yawing control, the control of being incorporated into the power networks, ceiling capacity Tracing Control, the control of permanent power, the problem that be used to solve that wind generator system unties the mooring rope to wind and cable in driftage, aspect such as stability and safety operation exists under Maximum Power Output, the high wind speed under the wind-electricity integration, low wind speed realizes the effective and safe of large-scale wind power generator incorporated in power network group operation is controlled.

Technical scheme: grid type speed-variable frequency-constant wind-driven generator group control method of the present invention comprises the active yawing control strategy, permanent power control strategy under ceiling capacity Tracing Control strategy, the high wind speed under the control strategy that is incorporated into the power networks, low wind speed:

Described active yawing control strategy may further comprise the steps:

A1. air velocity transducer records the interior mean wind speed of 10min greater than 3m/s, and wind wheel begins wind;

A2. judge whether wind wheel is finished wind, promptly judge | V|＞| V ₀| whether set up, wherein V is the yaw error signal that the wind vane transducer obtains, V ₀Be the driftage set point;

When differentiating is that then wind energy conversion system is not finished wind, and the driftage motor stops, driftage brake input;

When differentiating for being, then postpone 10s, discharge the driftage brake, starting driftage motor behind the 1s;

A3. judge the wind wheel yaw direction, judge promptly whether V＜0 sets up:

When differentiating is not, and the motor driven of then going off course cabin is by the tuning of going off course along the pointer direction;

When differentiating for being, the motor driven of then going off course cabin is by the anti-clockwise direction tuning of going off course;

A4. cable twines the sensor cable and twines the number of turns:

A41. judge that cable twines the number of turns and whether encloses between counterclockwise 1.8 circles clockwise 1.8:

Be that returning then that steps A 2 continues to judge whether need be to wind when being judged as;

When being judged as not, then change steps A 42 over to;

A42. judge that cable is wound between clockwise or counterclockwise 1.8 circles-3.8 circles:

Be to judge then whether unit is in generating state when being judged as:

When being judged as be, then do not carry out and separate winding that returning that steps A 2 continues to judge whether need be to wind;

When being judged as not, then carry out and separate winding, return steps A 1 after finishing;

When being judged as not, then change steps A 43 over to;

A43. judge that cable twines clockwise or whether winding counterclockwise reaches 3.8 circles:

When being judged as be, then unit switches to halted state by running status, and unit automatically terminates cable and twines, and returns steps A 1 after finishing;

When not being judged as not, returning then that steps A 2 continues to judge whether need be to wind;

The described control strategy that is incorporated into the power networks may further comprise the steps:

B1. differentiate generator speed and whether reach the rotating speed that is incorporated into the power networks, promptly differentiate ω _e〉=ω ₀Whether set up, wherein, ω _eBe generator speed, ω ₀Be minimum synchronous speed;

When differentiating is not, and then wind-driven generator continues the free-runing operation raising speed;

When differentiating for being, then change step B2 automatically over to, carry out wind-driven generator idle grid connection control strategy;

B2. detect three phase network voltage u _a, u _b, u _c, through type 1 formula is carried out three-phase/two-phase rotation transformation:

Formula 1

Obtain voltage vector u under the two synchronised speed rotating coordinate system d-q _d, u _q, θ=ω ₁T, ω ₁Be synchronous angular velocity, t is the time, adopts stator flux orientation, and the d axle is fixed on double-fed generator stator magnetic linkage direction, and the coordinate behind the field orientation is the m-t coordinate system, and corresponding subscript d changes m into, and q changes t into, and through type 2 obtains the amplitude u of line voltage space vector _sAnd phase angle theta _u:

$\left\{\begin{array}{c}{u}_s=\sqrt{u_m^2+u_t^2}\\ {\mathrm{\θ}}_u=2{\arctan }^{-1}\frac{u_t}{u_s+u_m}\end{array}\right.$ Formula 2

And then obtain reference stator magnetic linkage ψ according to formula 3 ₁ ^*And phase angle theta _s:

Formula 3

B3. according to reference stator magnetic linkage ψ ₁ ^*, calculate rotor m shaft current reference component i by (4) formula _M2 ^*

$i_{m2}^{*}=-\frac{{\mathrm{\ψ}}_1^{*}}{L_m}$ Formula 4

L _mBe the coefficient of mutual inductance of generator stator and rotor, the error of field orientation exists in the actual and network process, makes rotor t shaft current reference component i _T2 ^*Non-vanishing, relation satisfies formula 5 between rotor current and the voltage:

$\left\{\begin{array}{c}{u}_{m2}=u_{m2}^{\′}+\mathrm{\Δ}{u}_{m2}=(R_2+L_{2}p)i_{m2}-{\mathrm{\ω}}_s{L}_2{i}_{t2}\\ u_{t2}=u_{t2}^{\′}+\mathrm{\Δ}{u}_{t2}=(R_2+L_{2}p)i_{t2}+{\mathrm{\ω}}_s{L}_2{i}_{m2}\end{array}\right.$ Formula 5

u _M2, u _T2Be respectively rotor virtual voltage component, i _M2, i _T2Be rotor actual current component, u ' _M2=(R ₂+ L ₂P) i _M2, u ' _T2=(R ₂+ L ₂P) i _T2Be respectively with i _M2, i _T2Component of voltage with single order differential relationship, Δ u _M2=-ω _sL ₂i _T2, Δ u _T2=ω _sL ₂i _M2Be voltage compensation component, R ₂Be rotor winding resistance, L ₂Be rotor equivalent self-induction, ω _sBe slip angular velocity, p is a differential operator, realizes the rotor current closed-loop control by relational expression 5, promptly the excitation of rotor is controlled rotor m, t shaft current reference component i _M2 ^*, i _T2 ^*With actual current component i _M2, i _T2The deviation via controller add compensate component after regulating, obtain rotor m, t shaft voltage reference component u _M2 ^*, u _T2 ^*, pass through formula 6 coordinate transforms again:

$\left[\begin{array}{c}{u}_{\mathrm{\α}2}^{*}\\ u_{\mathrm{\β}2}^{*}\end{array}\right]=\left[\begin{array}{cc}\cos ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)& -\sin ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)\\ \sin ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)& \cos ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)\end{array}\right]\left[\begin{array}{c}{u}_{m2}^{*}\\ u_{t2}^{*}\end{array}\right]$ Formula 6

Obtain rotor voltage at α ₂-β ₂Component u on the coordinate _{α 2} ^*, u _{β 2} ^*, α wherein ₂-β ₂Coordinate is with ω _rAngular speed is rotated counterclockwise with respect to stator winding, θ _r=ω _rT is according to u _{α 2} ^*, u _{β 2} ^*Carry out the space vector of voltage pulse-width modulation, produce the drive signal of generator side converter, realize the idle grid connection control of double-fed generator:

When rotating speed changed, by closed-loop control, rotor was subjected to the AC excitation of changeable frequency;

When rotating speed reaches synchronous speed, ω _s=0, rotor is carried out DC excitation;

B4. pass through the control of B3 rotor current, make the generator unit stator electric voltage frequency not be subjected to rotation speed change and influence, and consistent, obtain specified stator magnetic linkage and satisfy the stator voltage of the condition that is incorporated into the power networks with the line voltage frequency, the switch that is incorporated into the power networks that closes a floodgate is started in stable back, and wind-driven generator is incorporated into the power networks;

Ceiling capacity Tracing Control strategy may further comprise the steps under the described low wind speed:

C1. when generator speed during less than rated speed, wind turbine generator adopts given power-speed curves control, and this curve is described by relational expression 7:

$P_{\mathrm{opt}}=\frac{1}{2}\mathrm{\ρ\π}{C}_{p\max }{\left(\frac{\mathrm{\ωR}}{{\mathrm{\λ}}_{\mathrm{opt}}}\right)}^3{R}^2$ Formula 7

ρ is an atmospheric density, and R is the wind wheel radius, and ω is a wind speed round, P _OptBe optimum operation power, by maximum power coefficient C _PmaxWith best tip speed ratio λ _OptDecision, its given reference value is calculated by the generator speed feedback, and with rotation speed change, the control generator speed makes power output follow the tracks of P _OptCurve;

C2. adopt indirect speed control strategy, the quadratic relationship formula 8 of torque and rotating speed:

$T_e^{*}=K_{\mathrm{opt}}{\mathrm{\ω}}^2$ Formula 8

T _e ^*Be torque desired value, K _OptBe proportionality coefficient, and according to stator flux orientation method among the B3, the generator electromagnetic torque is with best power coefficient:

T _e=-n _pL _mi _M1i _T2Formula 9

n _pBe number of pole-pairs, regulate rotor t shaft current component i by relational expression 9 _T2Just can realize generator torque T _eControl, make it follow the tracks of T _e ^*, realize generator speed control;

C3. when generator speed reached rated speed, wind turbine generator adopted permanent rotating speed control mode, and is same by regulating rotor t shaft current component i _T2, control generator torque T _eConstant, under the situation that continues to increase at wind speed, keep stabilization of speed constant in rated speed;

Permanent power control strategy may further comprise the steps under the described high wind speed:

Adopt variable pitch control method, measuring wind energy conversion system speed by tachometer is fed to compare with reference speed and draws the rotating speed deviation, input variable as the variable pitch controller, controller sends the order of blade pitch change amount according to deviation, the reference node elongation adds that this variable quantity requires to import the propeller pitch angle adjuster as new pitch angle, adjuster requires to regulate the wind machine oar leaf pitch according to new pitch angle, make that power train numerical value reduces rapidly under high wind speed, the restriction generator speed raises, and keeps output of a generator constant;

Require each control strategy coordinated operation according to unit operation.

In the described active yawing control strategy, wind wheel is measured the wind signal and is passed to drive motors by being installed in two photosensitive wind transducers in the wind vane and anemobiagraph wind, finish wind, wind vane and anemobiagraph are installed on the fixed support on the fiberglass engine room cover of wind turbine generator, rotate synchronously with the wind-driven generator group.

In the active yawing control strategy, for the above wind turbine generator of grid type MW class, the driftage rotating speed should be limited in the 0.085r/min.

In the ceiling capacity Tracing Control strategy, angle was constant when the blade pitch angle kept starting under the low wind speed.

Under the high wind speed in the permanent power control strategy, the variable pitch rate limit is between-10 °/s～10 °/s.

In the permanent power control strategy, the blade pitch angle is limited in 3 °～60 ° scopes under the high wind speed.

Beneficial effect: grid type speed-variable frequency-constant wind-driven generator group progress control method of the present invention has following beneficial effect:

1. the active yawing control strategy makes that unit can be stable and accurate to wind, makes wind wheel in time follow the tracks of wind direction and changes, and catches maximal wind-energy, detects the cable winding of drawing in the cabin simultaneously, and in time safety unties the mooring rope;

2. the control strategy that is incorporated into the power networks is controlled based on the rotor current excitation of stator flux observer, make stator voltage not influenced by rotating speed, realize variable speed constant frequency, be consistent on amplitude, frequency, phase place with line voltage, generator can be connected to the grid safely smoothly, reduces even eliminates the impulse current that is incorporated into the power networks;

3. ceiling capacity Tracing Control strategy adopts the indirect rotating speed control strategy of controlling generator speed by controlling torque under the low wind speed, avoided the inaccuracy of direct measuring wind, make the wind-powered electricity generation unit to change simultaneously according to wind speed, in time regulate rotating speed, being in operation keeps best tip speed ratio, obtains ceiling capacity

4. the permanent power control strategy under the high wind speed is regulated wind speed round by changing the blade pitch angle, stores or the release portion energy, has improved the stability of the flexible and output of drive system, limits the speed of variable pitch simultaneously, guarantees the safety and stability of system.

Description of drawings

Fig. 1 grid type speed-variable frequency-constant wind-driven generator group control flow chart,

Fig. 2 active yawing control flow chart,

Fig. 3 idle grid connection process rotor current control block diagram,

Indirect rotating speed control block diagram under the low wind speed of Fig. 4,

Fig. 5 best power and generator speed graph of a relation,

Variable pitch control control system block diagram under Fig. 6 high wind speed; Fig. 7 becomes oar rate limit adjuster control block diagram.

Embodiment

Grid type speed-variable frequency-constant wind-driven generator group control method of the present invention, its control flow mainly realize by following main control strategies as shown in Figure 1:

At first, before the startup of unit, finish wind wheel to wind, make the wind direction that axially aligns of wind wheel, a seizure maximal wind-energy, wind wheel are finished by the driftage control system wind, adopt the active yawing control strategy:

A1. air velocity transducer records the interior mean wind speed of 10min greater than 3m/s, and wind wheel begins wind;

A2. judge whether wind wheel is finished wind, promptly judge | V|＞| V ₀| whether set up, wherein V is the yaw error signal that the wind vane transducer obtains, V ₀Be the driftage set point;

When differentiating is that then wind energy conversion system is not finished wind, and the driftage motor stops, driftage brake input;

When differentiating for being, then postpone 10s, discharge the driftage brake, starting driftage motor behind the 1s;

A3. judge the wind wheel yaw direction, judge promptly whether V＜0 sets up:

When differentiating is not, and the motor driven of then going off course cabin is by the tuning of going off course along the pointer direction;

When differentiating for being, the motor driven of then going off course cabin is by the anti-clockwise direction tuning of going off course;

In the cabin driftage rotation process, the cable that extracts can twine, and is unlikely to excessive twisting fracture failure for guaranteeing cable, continuous detection streamer to twine the number of turns, surpasses to impose a condition the action of will untying the mooring rope.

A4. cable twines the sensor cable and twines the number of turns:

A41. judge that cable twines the number of turns and whether encloses between counterclockwise 1.8 circles clockwise 1.8:

Be that returning then that steps A 2 continues to judge whether need be to wind when being judged as;

When being judged as not, then change steps A 42 over to;

A42. judge that cable is wound between clockwise or counterclockwise 1.8 circles-3.8 circles:

Be to judge then whether unit is in generating state when being judged as:

When being judged as be, then do not carry out and separate winding that returning that steps A 2 continues to judge whether need be to wind;

When being judged as not, then carry out and separate winding, return steps A 1 after finishing;

When being judged as not, then change steps A 43 over to;

A43. judge that cable twines clockwise or whether winding counterclockwise reaches 3.8 circles:

When being judged as be, then unit switches to halted state by running status, and unit automatically terminates cable and twines, and returns steps A 1 after finishing;

When not being judged as not, returning then that steps A 2 continues to judge whether need be to wind;

The detailed process of active yawing control as shown in Figure 2.

Wind wheel is finished after the wind, and the wind wheel blade is rotated to 0 ° of direction of propeller pitch angle by the feathering state, after air-flow produces certain angle of attack to blade, wind wheel begins to rotate, and propeller pitch angle continues to rotate the free raising speed of wind wheel to 0 ° of direction, and drive generator and begin to rotate, do the preparation of being incorporated into the power networks.The control strategy that is incorporated into the power networks adopts following steps:

B1. differentiate generator speed and whether reach the rotating speed that is incorporated into the power networks, promptly differentiate ω _e〉=ω ₀Whether set up, wherein, ω _eBe generator speed, ω ₀Be minimum synchronous speed;

When differentiating is not, and then wind-driven generator continues the free-runing operation raising speed;

When differentiating for being, then change step B2 automatically over to, carry out wind-driven generator idle grid connection control strategy;

B2. detect three phase network voltage u _a, u _b, u _c, carry out three-phase/two-phase rotation transformation by (1) formula:

Obtain voltage vector u under the two synchronised speed rotating coordinate system d-q _d, u _q, θ=ω ₁T, ω ₁Be synchronous angular velocity, t is the time, adopts stator flux orientation, the d axle is fixed on double-fed generator stator magnetic linkage direction, and the coordinate behind the field orientation is the m-t coordinate system, and corresponding subscript d changes m into, q changes t into, obtains the amplitude u of line voltage space vector by (2) formula _sAnd phase angle theta _u:

$\left\{\begin{array}{c}{u}_s=\sqrt{u_m^2+u_t^2}\\ {\mathrm{\θ}}_u=2{\arctan }^{-1}\frac{u_t}{u_s+u_m}\end{array}\right.---\left(2\right)$

And then obtain reference stator magnetic linkage ψ according to formula (3) ₁ ^*And phase angle theta _s:

B3. according to reference stator magnetic linkage ψ ₁ ^*, calculate rotor m shaft current reference component i by (4) formula _M2 ^*

$i_{m2}^{*}=-\frac{{\mathrm{\ψ}}_1^{*}}{L_m}---\left(4\right)$

L _mBe the coefficient of mutual inductance of generator stator and rotor, the error of field orientation exists in the actual and network process, makes rotor t shaft current reference component i _T2 ^*Non-vanishing, relation satisfies formula (5) between rotor current and the voltage:

$\left\{\begin{array}{c}{u}_{m2}=u_{m2}^{\′}+\mathrm{\Δ}{u}_{m2}=(R_2+L_{2}p)i_{m2}-{\mathrm{\ω}}_s{L}_2{i}_{t2}\\ u_{t2}=u_{t2}^{\′}+\mathrm{\Δ}{u}_{t2}=(R_2+L_{2}p)i_{t2}+{\mathrm{\ω}}_s{L}_2{i}_{m2}\end{array}\right.---\left(5\right)$

u _M2, u _T2Be respectively rotor virtual voltage component, i _M2, i _T2Be rotor actual current component, u ' _M2=(R ₂+ L ₂P) i _M2, u ' _T2=(R ₂+ L ₂P) i _T2Be respectively with i _M2, i _T2Component of voltage with single order differential relationship, Δ u _M2=-ω _sL ₂i _T2, Δ u _T2=ω _sL ₂i _M2Be voltage compensation component, R ₂Be rotor winding resistance, L ₂Be rotor equivalent self-induction, ω _sBe slip angular velocity, p is a differential operator, realizes the rotor current closed-loop control by relational expression (5), promptly the excitation of rotor is controlled rotor m, t shaft current reference component i _M2 ^*, i _T2 ^*With actual current component i _M2, i _T2The deviation via controller add compensate component after regulating, obtain rotor m, t shaft voltage reference component u _M2 ^*, u _T2 ^*, the control block diagram as shown in Figure 3.Pass through formula (6) coordinate transform again:

$\left[\begin{array}{c}{u}_{\mathrm{\α}2}^{*}\\ u_{\mathrm{\β}2}^{*}\end{array}\right]=\left[\begin{array}{cc}\cos ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)& -\sin ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)\\ \sin ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)& \cos ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)\end{array}\right]\left[\begin{array}{c}{u}_{m2}^{*}\\ u_{t2}^{*}\end{array}\right]---\left(6\right)$

Obtain rotor voltage at α ₂-β ₂Component u on the coordinate _{α 2} ^*, u _{β 2} ^*, α wherein ₂-β ₂Coordinate is with ω _rAngular speed is rotated counterclockwise with respect to stator winding, θ _r=ω _rT is according to u _{α 2} ^*, u _{β 2} ^*Carry out the space vector of voltage pulse-width modulation, produce the drive signal of generator side converter, realize the idle grid connection control of double-fed generator:

When rotating speed changed, by closed-loop control, rotor was subjected to the AC excitation of changeable frequency;

When rotating speed reaches synchronous speed, ω _s=0, rotor is carried out DC excitation;

B4. pass through the control of B3 rotor current, make the generator unit stator electric voltage frequency not be subjected to rotation speed change and influence, and consistent, obtain specified stator magnetic linkage and satisfy the stator voltage of the condition that is incorporated into the power networks with the line voltage frequency, the switch that is incorporated into the power networks that closes a floodgate is started in stable back, and wind-driven generator is incorporated into the power networks;

The wind turbine generator that is incorporated into the power networks will be controlled according to the wind regime of outside, guarantees that unit can Maximum Power Output, safe and stable operation simultaneously.When extraneous wind speed is lower than the specified operating air velocity of unit, when wind-driven generator moves, adopt the ceiling capacity Tracing Control that keeps best tip speed ratio below rated speed, concrete steps are as follows:

C1. when generator speed during less than rated speed, wind turbine generator adopts given power-speed curves control, and this curve is described by relational expression (7):

$P_{\mathrm{opt}}=\frac{1}{2}\mathrm{\ρ\π}{C}_{p\max }{\left(\frac{\mathrm{\ωR}}{{\mathrm{\λ}}_{\mathrm{opt}}}\right)}^3{R}^2---\left(7\right)$

ρ is an atmospheric density, and R is the wind wheel radius, and ω is a wind speed round, P _OptBe optimum operation power, by maximum power coefficient C _PmaxWith best tip speed ratio λ _OptDecision, its given reference value is calculated by the generator speed feedback, and with rotation speed change, the control generator speed makes power output follow the tracks of P _OptCurve;

C2. adopt indirect speed control strategy, the quadratic relationship formula (8) of torque and rotating speed:

$T_e^{*}=K_{\mathrm{opt}}{\mathrm{\ω}}^2---\left(8\right)$

T _e ^*Be torque desired value, K _OptBe proportionality coefficient, and according to stator flux orientation method among the B3, the generator electromagnetic torque is with best power coefficient:

T _e＝-n _pL _mi _m1i _t2 (9)

n _pBe number of pole-pairs, regulate rotor t shaft current component i by relational expression (9) _T2Just can realize generator torque T _eControl, make it follow the tracks of T _e ^*, realize generator speed control.The specific implementation process as shown in Figure 4.

C3. when generator speed reached rated speed, wind turbine generator adopted permanent rotating speed control mode, and is same by regulating rotor t shaft current component i _T2, control generator torque T _eConstant, under the situation that continues to increase at wind speed, keep stabilization of speed constant in rated speed;

Certain 1.5MW unit specific implementation process as shown in Figure 5, v among the figure ₁＞v ₂＞v ₃＞v ₄＞v ₅＞v ₆＞v ₇＞v ₈Be wind speed, 1810r/min is the generator rated speed, reach rated speed after, generator will keep rotating speed constant, power continue to rise, up to rated power:

1. working as wind speed is v ₅, A ₂Point is the working point of generator, A ₁Point is the working point of wind energy conversion system, and the mechanical output of wind energy conversion system is greater than electrical power, and superfluous power equals the poor of 2 power, produces accelerating power, and rotating speed is increased, and target power is followed P _OptCurve continues to increase, and same, the working point of wind energy conversion system is also along v ₅Curvilinear motion is finally at A ₃Point crosses, and wind energy conversion system and generator are at A ₃Power reaches balance;

2. working as wind speed is v ₆, B ₁Be the working point of generator, B ₂Be the working point of wind energy conversion system, generator load is greater than the mechanical output of wind energy conversion system, and wind speed round reduces, and generator power is constantly revised, along P _OptCurvilinear motion, the wind energy conversion system power output is also along v ₆Curvilinear motion.Along with wind speed round reduces, the difference of wind wheel power and generator power reduces, finally at B ₃Point crosses, and reaches balance;

When extraneous wind speed is higher than the specified operating air velocity of unit, adopt permanent power control strategy:

By adopting variable pitch control method, measuring wind energy conversion system speed by tachometer is fed to compare with reference speed and draws the rotating speed deviation, input variable as the variable pitch controller, controller sends the order of blade pitch change amount according to deviation, the reference node elongation adds that this variable quantity requires to import the propeller pitch angle adjuster as new pitch angle, adjuster requires to regulate the wind machine oar leaf pitch according to new pitch angle, make that power train numerical value reduces rapidly under high wind speed, the restriction generator speed raises, keep output of a generator constant, the specific implementation process, shown in Fig. 6 (a), blade pitch angle excursion is limited by the pitch angle limiting element;

In the variable pitch process, to consider to become oar speed, generally be limited between-10 °/s～10 °/s, control by the variable pitch adjuster, its control block diagram is shown in Fig. 6 (b), pitch set-point and actual blade pitch value are benchmark normalization with the set-point, deviation is exported by the variable pitch rate limit blocks through amplifying 10 times.If output becomes oar speed between-0.1 °/s～0.1 °/s, then be output as zero through the dead band limiting module, do not carry out the change oar, this method is ignored the change oar order less than ± 0.1 °/s that comprises the dead band, eliminates noise to help adjuster.

More than each control strategy require and the external condition coordinative role according to unit operation, the assurance wind turbine generator is generator operation safely and efficiently.

Claims (6)

1. grid type speed-variable frequency-constant wind-driven generator group progress control method is characterized in that this method comprises the active yawing control strategy, permanent power control strategy under ceiling capacity Tracing Control strategy, the high wind speed under the control strategy that is incorporated into the power networks, low wind speed:

Described active yawing control strategy may further comprise the steps:

A1. air velocity transducer records the interior mean wind speed of 10min greater than 3m/s, and wind wheel begins wind;

A2. judge whether wind wheel is finished wind, promptly judge | V|＞| V ₀| whether set up, wherein V is the yaw error signal that the wind vane transducer obtains, V ₀Be the driftage set point;

When differentiating is that then wind energy conversion system is not finished wind, and the driftage motor stops, driftage brake input;

When differentiating for being, then postpone 10s, discharge the driftage brake, starting driftage motor behind the 1s;

A3. judge the wind wheel yaw direction, judge promptly whether V＜0 sets up:

When differentiating is not, and the motor driven of then going off course cabin is by the tuning of going off course along the pointer direction;

When differentiating for being, the motor driven of then going off course cabin is by the anti-clockwise direction tuning of going off course;

A4. cable twines the sensor cable and twines the number of turns:

A41. judge that cable twines the number of turns and whether encloses between counterclockwise 1.8 circles clockwise 1.8:

Be that returning then that steps A 2 continues to judge whether need be to wind when being judged as;

When being judged as not, then change steps A 42 over to;

A42. judge that cable is wound between clockwise or counterclockwise 1.8 circles-3.8 circles:

Be to judge then whether unit is in generating state when being judged as:

When being judged as be, then do not carry out and separate winding that returning that steps A 2 continues to judge whether need be to wind;

When being judged as not, then carry out and separate winding, return steps A 1 after finishing;

When being judged as not, then change steps A 43 over to;

A43. judge that cable twines clockwise or whether winding counterclockwise reaches 3.8 circles:

When being judged as be, then unit switches to halted state by running status, and unit automatically terminates cable and twines, and returns steps A 1 after finishing;

When not being judged as not, returning then that steps A 2 continues to judge whether need be to wind;

The described control strategy that is incorporated into the power networks may further comprise the steps:

B1. differentiate generator speed and whether reach the rotating speed that is incorporated into the power networks, promptly differentiate ω _e〉=ω ₀Whether set up, wherein, ω _eBe generator speed, ω ₀Be minimum synchronous speed;

When differentiating is not, and then wind-driven generator continues the free-runing operation raising speed;

When differentiating for being, then change step B2 automatically over to, carry out wind-driven generator idle grid connection control strategy;

B2. detect three phase network voltage u _a, u _b, u _c, through type 1 formula is carried out three-phase/two-phase rotation transformation:

Formula 1

Obtain voltage vector u under the two synchronised speed rotating coordinate system d-q _d, u _q, θ=ω ₁T, ω ₁Be synchronous angular velocity, t is the time, adopts stator flux orientation, and the d axle is fixed on double-fed generator stator magnetic linkage direction, and the coordinate behind the field orientation is the m-t coordinate system, and corresponding subscript d changes m into, and q changes t into, and through type 2 obtains the amplitude u of line voltage space vector _sAnd phase angle theta _u:

$\left\{\begin{array}{c}{u}_s=\sqrt{u_m^2+u_t^2}\\ {\mathrm{\θ}}_u=2\mathrm{arc}{\tan }^{-1}\frac{u_t}{u_s+u_m}\end{array}\right.$ Formula 2

And then obtain reference stator magnetic linkage ψ according to formula 3 ₁ ^*And phase angle theta _s:

Formula 3

B3. according to reference stator magnetic linkage ψ ₁ ^*, calculate rotor m shaft current reference component i by (4) formula _M2 ^*

$i_{m2}^{*}=-\frac{{\mathrm{\ψ}}_1^{*}}{L_m}$ Formula 4

L _mBe the coefficient of mutual inductance of generator stator and rotor, the error of field orientation exists in the actual and network process, makes rotor t shaft current reference component i _T2 ^*Non-vanishing, relation satisfies formula 5 between rotor current and the voltage:

$\left\{\begin{array}{c}{u}_{m2}=u_{m2}^{\′}+\mathrm{\Δ}{u}_{m2}=(R_2+L_{2}p)i_{m2}-{\mathrm{\ω}}_s{L}_2{i}_{t2}\\ u_{t2}=u_{t2}^{\′}+\mathrm{\Δ}{u}_{t2}=(R_2+L_{2}p)i_{t2}+{\mathrm{\ω}}_s{L}_2{i}_{m2}\end{array}\right.$ Formula 5

u _M2, u _T2Be respectively rotor virtual voltage component, i _M2, i _T2Be rotor actual current component,

U ' _M2=(R ₂+ L ₂P) i _M2, u ' _T2=(R ₂+ L ₂P) i _T2Be respectively with i _M2, i _T2Component of voltage with single order differential relationship, Δ u _M2=-ω _sL ₂i _T2, Δ u _T2=ω _sL ₂i _M2Be voltage compensation component, R ₂Be rotor winding resistance, L ₂Be rotor equivalent self-induction, ω _sBe slip angular velocity, p is a differential operator, realizes the rotor current closed-loop control by relational expression 5, promptly the excitation of rotor is controlled rotor m, t shaft current reference component i _M2 ^*, i _T2 ^*With actual current component i _M2, i _T2The deviation via controller add compensate component after regulating, obtain rotor m, t shaft voltage reference component u _M2 ^*, u _T2 ^*, pass through formula 6 coordinate transforms again:

$\left[\begin{array}{c}{u}_{\mathrm{\α}2}^{*}\\ u_{\mathrm{\β}2}^{*}\end{array}\right]=\left[\begin{array}{cc}\cos ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)& -\sin ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)\\ \sin ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)& \cos ({\mathrm{\θ}}_s-{\mathrm{\θ}}_r)\end{array}\right]\left[\begin{array}{c}{u}_{m2}^{*}\\ u_{t2}^{*}\end{array}\right]$ Formula 6

Obtain rotor voltage at α ₂-β ₂Component u on the coordinate _{α 2} ^*, u _{β 2} ^*, α wherein ₂-β ₂Coordinate is with ω _rAngular speed is rotated counterclockwise with respect to stator winding, θ _r=ω _rT is according to u _{α 2} ^*, u _{β 2} ^*Carry out the space vector of voltage pulse-width modulation, produce the drive signal of generator side converter, realize the idle grid connection control of double-fed generator:

When rotating speed changed, by closed-loop control, rotor was subjected to the AC excitation of changeable frequency;

When rotating speed reaches synchronous speed, ω _s=0, rotor is carried out DC excitation;

B4. pass through the control of B3 rotor current, make the generator unit stator electric voltage frequency not be subjected to rotation speed change and influence, and consistent, obtain specified stator magnetic linkage and satisfy the stator voltage of the condition that is incorporated into the power networks with the line voltage frequency, the switch that is incorporated into the power networks that closes a floodgate is started in stable back, and wind-driven generator is incorporated into the power networks;

Ceiling capacity Tracing Control strategy may further comprise the steps under the described low wind speed:

C1. when generator speed during less than rated speed, wind turbine generator adopts given power-speed curves control, and this curve is described by relational expression 7:

$P_{\mathrm{opt}}=\frac{1}{2}\mathrm{\ρ\π}{C}_{p\max }{\left(\frac{\mathrm{\ωR}}{{\mathrm{\λ}}_{\mathrm{opt}}}\right)}^3{R}^2$ Formula 7

ρ is an atmospheric density, and R is the wind wheel radius, and ω is a wind speed round, P _OptBe optimum operation power, by maximum power coefficient C _PmaxWith best tip speed ratio λ _OptDecision, its given reference value is calculated by the generator speed feedback, and with rotation speed change, the control generator speed makes power output follow the tracks of P _OptCurve;

C2. adopt indirect speed control strategy, the quadratic relationship formula 8 of torque and rotating speed:

$T_e^{*}=K_{\mathrm{opt}}{\mathrm{\ω}}^2$ Formula 8

T _e ^*Be torque desired value, K _OptBe proportionality coefficient, and according to stator flux orientation method among the B3, the generator electromagnetic torque is with best power coefficient:

T _e=-n _pL _mi _M1i _T2Formula 9

n _pBe number of pole-pairs, regulate rotor t shaft current component i by relational expression 9 _T2Just can realize generator torque T _eControl, make it follow the tracks of T _e ^*, realize generator speed control;

C3. when generator speed reached rated speed, wind turbine generator adopted permanent rotating speed control mode, and is same by regulating rotor t shaft current component i _T2, control generator torque T _eConstant, under the situation that continues to increase at wind speed, keep stabilization of speed constant in rated speed;

Permanent power control strategy may further comprise the steps under the described high wind speed:

Adopt variable pitch control method, measuring wind energy conversion system speed by tachometer is fed to compare with reference speed and draws the rotating speed deviation, input variable as the variable pitch controller, controller sends the order of blade pitch change amount according to deviation, the reference node elongation adds that this variable quantity requires to import the propeller pitch angle adjuster as new pitch angle, adjuster requires to regulate the wind machine oar leaf pitch according to new pitch angle, make that power train numerical value reduces rapidly under high wind speed, the restriction generator speed raises, and keeps output of a generator constant;

Require each control strategy coordinated operation according to unit operation.

2. grid type speed-variable frequency-constant wind-driven generator group progress control method according to claim 1, it is characterized in that in the described active yawing control strategy, wind wheel is measured the wind signal and is passed to drive motors by being installed in two photosensitive wind transducers in the wind vane and anemobiagraph wind, finish wind, wind vane and anemobiagraph are installed on the fixed support on the fiberglass engine room cover of wind turbine generator, rotate synchronously with the wind-driven generator group.

3. grid type speed-variable frequency-constant wind-driven generator group progress control method according to claim 1 is characterized in that in the active yawing control strategy, and for the above wind turbine generator of grid type MW class, the driftage rotating speed should be limited in the 0.085r/min.

4. grid type speed-variable frequency-constant wind-driven generator group progress control method according to claim 1 is characterized in that under the low wind speed that in the ceiling capacity Tracing Control strategy, angle was constant when the blade pitch angle kept starting.

5. grid type speed-variable frequency-constant wind-driven generator group progress control method according to claim 1 is characterized in that under the high wind speed in the permanent power control strategy, and the variable pitch rate limit is between-10 °/s～10 °/s.

6. grid type speed-variable frequency-constant wind-driven generator group progress control method according to claim 1 is characterized in that under the high wind speed that in the permanent power control strategy, the blade pitch angle is limited in 3 °～60 ° scopes.

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