CN100530934C - Control method for inhibiting input electric network power fluctuation in wind power generation system - Google Patents

Abstract

The invention relates to the field of a wind power generation system, and discloses particularly a controlling means to restrain the power fluctuation of an input power network in the wind power generation system. Based on the wind power generation system provided with a convertor and a DC side capacitor, a method of the invention has the control steps as follows: in step one, the input power Pin of the DC side capacitor is calculated; in step two, the output power Pout of the DC side capacitor is calculated; in step three, the calculated value udcj of DC side capacitor voltage is evaluated; in step four, the calculated value udcj of the DC side capacitor voltage is used as a voltage instruction value to control a PWM inverter, and when the DC side capacitor voltage udc is 85 percent to 110 percent of the voltage rating of the DC side capacitor, the power fluctuation of the input power network can be restrained. The invention utilizes the energy-stored effect of the DC side capacitor to restrain the output power fluctuation caused by the power fluctuation corresponding to wind energy through properly adjusting the DC side voltage, no extra auxiliary devices are needed, and the controlling means can be widely used in the wind power generation system.

Description

The control method that suppresses the fluctuation of input grid power in a kind of wind generator system

Technical field

The present invention relates to the wind generator system field, relate in particular to the control method that suppresses the fluctuation of input grid power, specifically utilize dc bus capacitor to suppress the control method of power fluctuation.

Background technology

In recent years, along with the continuous aggravation of energy crisis and environmental problem, national governments all are put in attentiveness the energy and seek.Wind energy in the regenerative resource is tending towards industrialization and receives much concern because its reserves are bigger, pollution-free.The cost and the cost of wind power system itself are higher, so the wind field operator pursues the utilance that maximal wind-energy is used to improve system.Simultaneously, wind itself has randomness and variability, and the cube of wind energy and wind speed is directly proportional, and the variation of wind energy is more violent when the wind speed acute variation.When the bigger wind generator system of capacity is connected into electrical network or during at the independent powering load in remote districts, the former is because the influence that the power of the continuous fluctuation of injecting to electrical network can bring frequency stability to electric power system, the same because fluctuation of power output of the latter and brings influence to load.

Find that by literature search the researchers of wind generator system have proposed the method for power fluctuation in the multiple solution wind generator system, mainly can be divided into two classes, a class is to utilize the control of propeller pitch angle to catch level and smooth relatively wind energy; Another kind of is to utilize energy-storage travelling wave tube to come the mobile of energy controlled.T.Senjyu. in the first kind, R.Sakamoto. wait the scholar at document 1. " Output Power Leveling of WindTurbine Generator for All Operating Regions by Pitch Angle Control " (IEEETransactions on Energy conversion, June 2006, Vol.21, No.2, pp.467-475.), 2. " Output Power Leveling of Wind Turbine Generator by Pitch Angle Control UsingAdaptive Control Method " (2004 International Conference on Power SystemTechnology, Nov.2004, Vol.1, pp.834-839.), 3. " Output Power Leveling of WindFarm Using Pitch Angle Control with Fuzzy Neural Network " (IEEE PowerEngineering Society General Meeting, June 2006,8pp, 1709377.), 4. " OutputPower Leveling of Wind Turbine by Pitch Angle Control Using H ∞ Control " (Power Systems Conference and Exposition, 2006, PSCE 2006, Oct.-Nov.2006, pp.2044-2049.) propose in full blast speed scope, to use such as adaptive control, Fuzzy Neural-network Control, robust controls etc. are controlled to obtain smoothly to import the effect of grid power propeller pitch angle, this kind method has reduced the maximal wind-energy utilization of system, and control is comparatively complicated, the mechanical part of propeller pitch angle needs constantly action, and bigger mechanical wear is arranged.In second class, scholar T.Kinjo etc. are at document " Output Levelingof Renewable Energy by Electric Double-Layer Capacitor Applied for EnergyStorage System " (IEEE Transactions on Energy conversion, Vol.21, No.1, March2006, pp.221-227.) in the accumulator that in the past comprised electrochemical capacitor is improved, its capacity does not rely on dc voltage, and reduced the quantity of series connection electrolysis capacitor cell, this system has comparatively complicated structure, needs comparatively complicated control; Scholar J.D.Boyes etc. are at document " Technologies forEnergy Storage Flywheels and Super Conducting Magnetic Energy Storage " (IEEEPower Engineering Society Summer Meeting, Vol.3, July 2000, pp.1548-1550.) superconductive energy storage system and flywheel energy storage system have been contrasted, superconductive energy storage system can discharge or absorb a large amount of power in a short period of time, need cryogenic refrigeration cabinet and subsidiary subsystem accordingly, flywheel energy storage system is converted into mechanical output with electrical power, there is requirement the infield and needs safeguard.

Scholar W.Li etc. are at document " Attenuation of Wind Power Fluctuations in WindTurbine Generators using a DC Bus Capacitor Based Filtering Control Scheme " (Industry Applications Conference, IAS 2006, Vol.1, Oct.2006, pp.216-221.) mention this similar thought of power of coming the absorption portion fluctuation with dc bus capacitor in, the simulating, verifying of this kind method is based on two PWM current transformers of direct-drive wind power system, use AGC controller (Wen Zhongwei discusses in detail) and comparatively complicated filtering algorithm and calculate the instruction of dc voltage, purpose is the power fluctuation that absorbs in the particular frequency range.Wind speed is the amplitude difference of different frequency scope wind energy fluctuation simultaneously not, needs to design different filtering algorithms under different wind fields and different device.And institute's extracting method only absorbs the interior power fluctuation of particular frequency range in the literary composition, when reducing the capacitor energy storage system capacity, has also reduced the effect that suppresses power fluctuation in the wind generator system.

Summary of the invention

The objective of the invention is to propose to suppress in a kind of wind generator system the control method of input grid power fluctuation, this wind generator system adopts the PWM inverter, utilize dc bus capacitor to suppress power fluctuation, and, this method can effectively be utilized existing apparatus, control algolithm is simple, need not extra servicing unit.

The present invention is based on the wind generator system that adopts the PWM inverter and have the dc bus capacitor device, its principle be the energy storage effect that utilizes the dc bus capacitor device with and dc voltage allow the characteristic that fluctuates within the specific limits, suppress to become the fluctuation of device power output by suitable adjusting because of the wind energy power fluctuation causes PWM contrary 2 to dc voltage, when purpose is to realize maximal wind-energy capture, reduce influence to electrical network.

Technical scheme of the present invention is to realize like this, the control method that suppresses the fluctuation of input grid power in a kind of wind generator system, this method is based on the wind generator system with voltage-source type current transformer, this wind generator system comprises wind energy conversion system, this wind energy conversion system is connected with synchronous generator is coaxial, the three-phase output end of synchronous generator is connected successively with rectifier, PWM inverter and electrical network, between described rectifier output end and the PWM inverter input and be connected to capacitor, its capacitance is C, and rated voltage is u _Dce, the DC side input power is P _In, the DC side power output is P _Out, it is characterized in that controlled step is as follows:

Step 1 is calculated the input power P of dc bus capacitor device _In, P _In=T _m* ω _m-R _s* 1.5 * i _g ², T wherein _m, ω _mBe synchronous generator torque and mechanical separator speed, R _sBe the stator resistance of synchronous generator, i _gBe stator torque current through synchronous generator after the Park conversion;

Step 2 is calculated the power output P of dc bus capacitor device _Out, $P_{\mathrm{out}}=\frac{1}{2}{C}_p\mathrm{\&rho;}{{\mathrm{AV}}_{\_\mathrm{wind}\_\mathrm{<figure-callout\; id="3"\; label="average"\; filenames="C20081001743000141.png,C20081001743000151.png"\; state="\{\{state\}\}">average</figure-callout>}}}^3,$ C _pBe power coefficient, ρ is an atmospheric density, and A is a swept area of rotor, V _{_ wind_average}Statistical average wind speed for wind power generation plant;

Step 3 is asked for the voltage calculated value u of dc bus capacitor device _Dcj, according to Δ P=P _In-P _OutWith ${\&Integral;}_0^t{u}_{\mathrm{dcj}}\&times;C\&times;\frac{{\mathrm{du}}_{\mathrm{dcj}}}{\mathrm{d\&tau;}}\&times;\mathrm{d\&tau;}={\&Integral;}_0^t\mathrm{\&Delta;P}\&times;\mathrm{d\&tau;},$ Wherein t is the time of integration, and τ is an integration variable, and Δ P is the instantaneous power of DC side, can get $u_{\mathrm{dcj}}=\sqrt{\frac{2}{C}\&times;{\&Integral;}_0^t(P_{\mathrm{in}}-P_{\mathrm{out}})\&times;\mathrm{d\&tau;}+{{\mathrm{<figure-callout\; id="2"\; label="u\; dce"\; filenames="C20081001743000142.png,C20081001743000151.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{dce}}}^2},$ Wherein, u _DceBe the initial value of integration, just the dc voltage rated value;

Step 4 is utilized dc voltage calculated value u _DcjControl the PWM inverter as the dc voltage command value, guarantee at dc capacitor voltage u _DcBe 85%u _Dce～110%u _DceIn, can suppress to import the power fluctuation of electrical network.

Further being optimized for of step 4 of the present invention: the PWM inverter adopts the dicyclo control of current inner loop outer voltage, dc voltage calculated value u _DcjCommand value u as Voltage loop _{Dc_ref}, still, work as u _Dcj＞110%u _DceThe time, u _{Dc_ref}Get 110%u _Dce, work as u _Dcj＜85%u _DceThe time, u _{Dc_ref}Get 85%u _Dce

Further being optimized for of step 4 of the present invention: monitoring dc voltage calculated value u _Dcj, work as 85%u _Dce＜u _Dcj＜110%u _DceThe time, the PWM inverter adopts electric current loop to control separately; Work as u _Dcj＞110%u _DceThe time, the PWM inverter adopts the dicyclo control of current inner loop outer voltage, the command value u of Voltage loop _{Dc_ref}Get 110%u _DceWork as u _Dcj＜85%u _DceThe time, the PWM inverter adopts the dicyclo control of current inner loop outer voltage, the command value u of Voltage loop _{Dc_ref}Get 85%u _Dce

Since the energy storage effect that the present invention has utilized the dc bus capacitor device with and dc voltage allow the characteristic that fluctuates within the specific limits, by the suitable adjusting of dc voltage being suppressed to cause because of the wind energy power fluctuation fluctuation of power output, when need not extra servicing unit, realized maximal wind-energy capture, reduced influence electrical network.And the present invention utilizes dc voltage calculated value u _DcjAt 85%u _Dce～110%u _DceIn, the PWM inverter adopts electric current loop to control separately, can better improve response speed.Voltage loop control of the present invention is especially as dc voltage calculated value u _DcjAt 85%u _Dce～110%u _DceOutside the time, Voltage loop command value u _{Dc_ref}Get boundary value 85%u _DceOr 110%u _Dce, can utilize the energy storage effect of capacitor to greatest extent, can stably guarantee the safety of capacitor again, so that the safety of whole system.

Description of drawings

Fig. 1 is the wind generator system structure chart of voltage-source type current transformer.

Fig. 2 is PWM inverter control block diagram.

Fig. 3 is for using the simulated effect figure of one embodiment of the present of invention.

Wherein: Fig. 3 (a) is wind field 10min actual measurement fluctuations in wind speed figure;

Fig. 3 (b) is the actual wind energy wave pattern of the 10min of corresponding diagram 3 (a);

Fig. 3 (c) is given voltage of DC side (solid line) and DC side virtual voltage (dotted line) wave pattern;

Fig. 3 (d) is for the maximal wind-energy (dotted line) of catching and import power (solid line) wave pattern of electrical network after using the present invention;

Fig. 4 is equivalent experimental circuit of the present invention and experiment effect oscillogram;

Wherein: Fig. 4 (a) is an equivalent experimental circuit of the present invention;

Fig. 4 (b) is not for adopting equivalent experiment effect oscillogram of the present invention;

Fig. 4 (c) is for adopting equivalent experiment effect oscillogram of the present invention.

In Fig. 4 (b), Fig. 4 (c):

CH1 (1.): rectifier bridge input ac voltage (v _In(t)), 100v/div;

CH2 (2.): A phase line voltage (v _a(t)), 100v/div;

CH3 (3.): A phase electrical network input current (i _a(t)), 10A/div;

CH4 (4.): dc voltage, 100v/div.

Embodiment

The present invention is described in further detail below in conjunction with the drawings and specific embodiments.

With reference to Fig. 1, the wind power generation plant of voltage-source type current transformer, this wind power generation plant comprises wind energy conversion system, wind is with wind speed V _WindThe drive wind energy conversion system rotates, and wind energy conversion system is connected with magneto alternator is coaxial, and torque is T _m, rotating speed is ω _m(after the Park conversion, the port voltage and the torque current of generator are respectively V to the three-phase output end of magneto alternator _g, i _g) link to each other with the PWM rectifier, PWM rectifier output is joined with PWM inverter input, the PWM inverter output end (after 3/2 conversion and rotation transformation, inverter identical with the electrical network junction with A to voltage and current be respectively V _d, i _d) inserting electrical network, between described PWM rectifier output and the PWM inverter input and be connected to capacitor, capacitance is C, its rated operational voltage is u _Dce, capacitance current is i _Dc, actual DC side voltage is u _Dc, the DC side input power is P _In, power output is P _OutDc voltage u _DcAdjustable, and its modification scope is capacitor load voltage value u _Dce85%～110%.

With reference to Fig. 2, the PWM inverter adopts the dicyclo control of sinusoidal pulse width modulation technology (SPWM) and current inner loop outer voltage.The Voltage loop instruction is u _{Dc_ref}With actual DC side magnitude of voltage u _DcError signal after voltage regulator as electric current loop instruction i _{D_ref}, electric current loop instruction i _{D_ref}With inverter output current detection signal i _dDifference again through sending into PWM ripple maker behind the current regulator, PWM ripple maker produces the pulse signal of control PWM inverter.

Control method of the present invention specifically is achieved in that

Step 1 is calculated the input power P of dc bus capacitor device _In

Ignore mechanical friction loss, eddy current loss and the magnetic hysteresis loss of magneto alternator, specifically be calculated as follows:

P _in＝T _m×ω _m-ΔP _G-P _converter1 (1)

ΔP _G＝R _s×1.5×i _g ² (2)

P _converter1≈0 (3)

Can get from formula (1) (2) (3): P _In=T _m* ω _m-R _s* 1.5 * i _g ²(4)

In the formula: T _m, ω _m(magneto alternator) torque of-wind energy conversion system and mechanical separator speed are measured value;

Δ P _G, P _Converter1The loss of-magneto alternator and PWM rectifier;

R _sThe stator resistance of-magneto alternator is the parameter of electric machine;

i _gThe stator torque current of magneto alternator after the-process Park conversion.

Step 2 is calculated the power output P of dc bus capacitor device _Out

Not during the loss of taking into account inverter, P _OutAlso be the average power of PWM inverter input electrical network, specifically be calculated as follows:

$P_{\mathrm{out}}=\frac{1}{2}{C}_p\mathrm{\&rho;}{{\mathrm{AV}}_{\_\mathrm{wind}\_\mathrm{average}}}^3---\left(5\right)$

In the formula:

C _p-power coefficient;

ρ-atmospheric density is generally 1.25kg/m ³

The A-swept area of rotor is π R ², R is the wind energy conversion system radius, is system parameters;

V _{_ wind_average}---mean wind speed, by obtaining the wind speed statistics of wind power generation plant, can calculate mean wind speed V _{_ wind_average}, be system parameter values.

Step 3 is asked for the voltage calculated value u of dc bus capacitor device _Dcj

Make the power of input electrical network level and smooth relatively, the dc bus capacitor device the instantaneous power value that should absorb or discharge be Δ P, wherein:

ΔP＝P _in-P _out (6)

Again because:

$\mathrm{\&Delta;P}=i_{\mathrm{dc}}\&times;u_{\mathrm{dc}}=C\&times;u_{\mathrm{dc}}\&times;\frac{{\mathrm{du}}_{\mathrm{dc}}}{\mathrm{dt}}---\left(7\right)$

So have ${\&Integral;}_0^t{u}_{\mathrm{dcj}}\&times;C\&times;\frac{{\mathrm{du}}_{\mathrm{dcj}}}{\mathrm{d\&tau;}}\&times;\mathrm{d\&tau;}={\&Integral;}_0^t\mathrm{\&Delta;P}\&times;\mathrm{d\&tau;}---\left(8\right)$

$u_{\mathrm{dcj}}=\sqrt{\frac{2}{C}\&times;{\&Integral;}_0^t(P_{\mathrm{in}}-P_{\mathrm{out}})\&times;\mathrm{d\&tau;}+{u_{\mathrm{dce}}}^2}---\left(9\right)$

In the formula: the instantaneous power of Δ P---DC side, calculated value;

C, i _Dc, u _Dc, u _Dcj---dc bus capacitor, electric current, instantaneous voltage and calculated value;

T---the time of integration;

τ---integration variable;

u _Dce---the initial value of integration, the just voltage rating of dc bus capacitor device.

Step 4 is utilized dc voltage calculated value u _DcjControl the PWM inverter as the dc voltage command value, guarantee at dc capacitor voltage u _DcBe 85%u _Dce～110%u _DceIn, can suppress to import the power fluctuation of electrical network.

Further being optimized for of step 4 of the present invention: the PWM inverter adopts the dicyclo control of current inner loop outer voltage, dc voltage calculated value u _DcjCommand value u as Voltage loop _{Dc_ref}, work as u _Dcj＞110%u _DceThe time, u _{Dc_ref}Get 110%u _Dce, work as u _Dcj＜85%u _DceThe time, u _{Dc_ref}Get 85%u _Dce

Further being optimized for of step 4 of the present invention: monitoring dc voltage calculated value u _Dcj, work as 85%u _Dce＜u _Dcj＜110%u _DceThe time, the PWM inverter adopts electric current loop to control separately; Work as u _Dcj＞110%u _DceThe time, the PWM inverter adopts the dicyclo control of current inner loop outer voltage, the command value u of Voltage loop _{Dc_ref}Get 110%u _DceWork as u _Dcj＜85%u _DceThe time, the PWM inverter adopts the dicyclo control of current inner loop outer voltage, the command value u of Voltage loop _{Dc_ref}Get 85%u _Dce

Current loop control principle of the present invention is according to input grid power P _Out=i _d* V _dSo the pass between dc voltage and the active current is:

${\&Integral;}_0^t{i}_d\&times;V_d\&times;\mathrm{d\&tau;}={\&Integral;}_0^t(P_{\mathrm{in}}-u_{\mathrm{dc}}\&times;C\&times;\frac{{\mathrm{du}}_{\mathrm{dc}}}{\mathrm{d\&tau;}})\&times;\mathrm{d\&tau;}---\left(10\right)$

In the formula: V _d, i _dFor after 3/2 conversion and rotation transformation, the PWM inverter identical with the electrical network junction with A to voltage and current.Control i _dConstant, then in (10) in the sign of integration of equation left side value be steady state value, also must need in the sign of integration of the right constant, and DC side input power P _InItself fluctuate, so must have u this moment with wind speed _DcP is offset in fluctuation _InVariation come the balance equation, just can by control i _dThe constant u that controls indirectly _Dc, the effect that utilizes capacitor to absorb or release energy reaches the purpose that suppresses the fluctuation of input grid power.And the present invention utilizes dc voltage calculated value u _DcjAt 85%u _Dce～110%u _DceWhen interior, the PWM inverter adopts electric current loop to control separately, can better improve response speed.

In order to verify the present invention, Fig. 3 has provided simulated effect of the present invention.This emulation basis is the air speed data of actual measurement in the Chinese somewhere wind field 10 minutes, because the inventive method is an additional function on dc bus capacitor device original function, so the parameter selection can be selected according to the requirement of system design fully.Can obtain from analogous diagram, corresponding to Fig. 3 (a) wind speed, the variable power of wind energy correspondence is very acutely with reference to Fig. 3 (b), and the control generator carries out maximal wind-energy capture.After adopting the inventive method, because the variation of control dc voltage (dotted line) trace command (solid line) is shown in Fig. 3 (c), absorbed the power that to import the fluctuation of electrical network, by Fig. 3 (d) as can be seen, power (solid line) power (dotted line) of catching with respect to wind energy conversion system of input electrical network is level and smooth many.In the time of about 8.3 minutes, because dc voltage reached higher limit, so no longer play the effect of power control, the power following of importing electrical network is at this moment caught the fluctuation of power and is fluctuateed.This comparative descriptions can obtain the effect of good inhibition input grid power fluctuation in the scope that this control method works.Certainly, when cost allowed, the value of dc bus capacitor was big more and the dc capacitor voltage selection is high more, and the operational time of this control method is long more, and is good more to the control effect of power.

Fig. 4 has provided the experiment effect figure of equivalent control method among the present invention.This experiment is on the experiment porch of 2kVA, and with reference to Fig. 4 (a), the system experimentation circuit is by AC power V _InGive diode uncontrollable rectifier bridge 1 power supply, the uncontrollable rectifier bridge 1 of diode, PWM inverter 2, inlet wire inductance L and electrical network are connected successively, and dc bus capacitor device C is attempted by between the uncontrollable rectifier bridge 1 of diode, the PWM inverter 2.For PWM inverter 2, replace the input effect of former PWM rectifier with the uncontrollable rectifier bridge 1 approximate simulation current source characteristic of prime diode.

Concrete experimental waveform is with reference to Fig. 4 (b) and Fig. 4 (c), 1. waveform is the input voltage (representing the fluctuation of input power) of rectifier bridge, 2. waveform is electrical network A phase voltage, and 3. waveform is electrical network A phase input current (representative input grid power), and 4. waveform is dc voltage.By relatively getting, adopt the instruction of equivalent control by direct given electric current loop after, electrical network input current amplitude (c) changes when not adopting equivalent control (b) less, has meaned smoothly the power fluctuation of importing electrical network.This comparative descriptions is in the scope that this control method works, can obtain the effect of good inhibition input grid power fluctuation, and the inventive method is not only applicable to the topological structure that prime is the PWM rectifier, is equally applicable to the topological structure that prime is uncontrollable rectification.

Claims (3)

1, the control method that suppresses the fluctuation of input grid power in a kind of wind generator system, this method is based on the wind generator system with voltage-source type current transformer, this wind generator system comprises wind energy conversion system, this wind energy conversion system is connected with synchronous generator is coaxial, the three-phase output end of synchronous generator is connected successively with rectifier, PWM inverter and electrical network, between described rectifier output end and the PWM inverter input and be connected to capacitor, its capacitance is C, and rated voltage is u _Dce, the DC side input power is P _In, the DC side power output is P _Out, it is characterized in that controlled step is as follows:

Step 1 is calculated the input power P of dc bus capacitor device _In, P _In=T _m* ω _m-R _s* 1.5 * i _g ², T wherein _m, ω _mBe synchronous generator torque and mechanical separator speed, R _sBe the stator resistance of synchronous generator, i _gBe stator torque current through synchronous generator after the Park conversion;

Step 2 is calculated the power output P of dc bus capacitor device _Out, $P_{\mathrm{out}}=\frac{1}{2}{C}_p\mathrm{\&rho;}{{\mathrm{AV}}_{\_\mathrm{wind}\_\mathrm{average}}}^3,$ C _pBe power coefficient, ρ is an atmospheric density, and A is a swept area of rotor, V _{_ wind_average}Statistical average wind speed for wind power generation plant;

Step 3 is asked for the voltage calculated value u of dc bus capacitor device _Dcj, according to Δ P=P _In-P _OutWith ${\&Integral;}_0^t{u}_{\mathrm{dcj}}\&times;C\&times;\frac{{\mathrm{du}}_{\mathrm{dcj}}}{\mathrm{d\&tau;}}\&times;\mathrm{d\&tau;}={\&Integral;}_0^t\mathrm{\&Delta;P}\&times;\mathrm{d\&tau;},$ Wherein t is the time of integration, and τ is an integration variable, and Δ P is the instantaneous power of DC side, can get $u_{\mathrm{dcj}}=\sqrt{\frac{2}{C}\&times;{\&Integral;}_0^t(P_{\mathrm{in}}-P_{\mathrm{out}})\&times;\mathrm{d\&tau;}+{u_{\mathrm{dce}}}^2},$ Wherein, u _DceBe the initial value of integration, just the dc voltage rated value;

Step 4 is utilized dc voltage calculated value u _DcjControl the PWM inverter as the dc voltage command value, guarantee at dc capacitor voltage u _DcBe 85%u _Dce～110%u _DceIn, can suppress to import the power fluctuation of electrical network.

2, suppress the control method of input grid power fluctuation in a kind of wind generator system according to claim 1, it is characterized in that the described dc voltage calculated value u that utilizes _DcjControlling the PWM inverter as the dc voltage command value, specifically is the dicyclo control that the PWM inverter adopts the current inner loop outer voltage, dc voltage calculated value u _DcjCommand value u as Voltage loop _{Dc_ref}, still, work as u _Dcj＞110%u _DceThe time, u _{Dc_ref}Get 110%u _Dce, work as u _Dcj＜85%u _DceThe time, u _{Dc_ref}Get 85%u _Dce

3, suppress the control method of input grid power fluctuation in a kind of wind generator system according to claim 1, it is characterized in that the described dc voltage calculated value u that utilizes _DcjControlling the PWM inverter as the dc voltage command value, specifically is monitoring dc voltage calculated value u _Dcj, work as 85%u _Dce≤ u _Dcj≤ 110%u _DceThe time, the PWM inverter adopts electric current loop to control separately; Work as u _Dcj＞110%u _DceThe time, the PWM inverter adopts the dicyclo control of current inner loop outer voltage, the command value u of Voltage loop _{Dc_ref}Get 110%u _DceWork as u _Dcj＜85%u _DceThe time, the PWM inverter adopts the dicyclo control of current inner loop outer voltage, the command value u of Voltage loop _{Dc_ref}Get 85%u _Dce

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