CN104578149B - Method for controlling predicted duty cycles of doubly-fed wind power generation system grid-side converter - Google Patents

Abstract

The invention relates to a control method for a doubly-fed wind power generation system grid-side converter, and aiming at structure characteristics and control demands of the doubly-fed wind power generation system grid-side converter, provides a method for controlling predicted duty cycles of the doubly-fed wind power generation system grid-side converter. The method comprises the following steps: obtaining a three-phase voltage value and a three-phase current value of a power grid through a voltage and current sampling circuit, and obtaining a horizontal axis alpha component and a vertical axis beta component of the power grid voltage value, an axis alpha component and an axis beta component of the power grid current value under a two-phase stationary reference frame after coordinate transformation; obtaining a real-time phase angle theta(s) of the power grid voltage after the axis alpha component and the axis beta component of the voltage value are processed through a phase-locked loop, and determining three-phase optimal duty cycles da', db' and dc' through duty cycle equivalent reconstitution. The method provided by the invention is mainly used for controlling the wind power generation system grid-side converter.

Description

Dual feedback wind power generation system grid side converter predicts Duty ratio control method

Technical field

The present invention relates to a kind of control method of dual feedback wind power generation system grid side converter；Specifically, it is related to double-fed wind Force generating system grid side converter predicts Duty ratio control method.

Background technology

The stator of dual feedback wind power generation system directly couples with electrical network, and rotor Jing bidirectional power converters are connected with electrical network, As shown in Figure 1.When wind speed changes, motor speed changes, and by the frequency for controlling rotor excitation current, it is fixed to make Sub- frequency-invariant, realizes variable speed constant frequency generator.In the running of dual feedback wind power generation system, the power of rotor circuit is flow through For slip power, converter cost is reduced.Additionally, doubly-fed variable-speed constant-frequency wind-power electricity generation scheme can also realize it is active, idle Uneoupled control, the reactive-load compensation to electrical network can be realized, favorably according to the corresponding perception of the requirement of electrical network output or capacitive reactive power In the stable operation of electrical network.

In the running of dual feedback wind power generation system, grid side converter and rotor side converter cooperate, in real time Adjust the running status of double-fed generator.Wherein, grid side converter realizes electromotor by maintaining stablizing for DC bus-bar voltage The real-time Transmission of active power between rotor and electrical network；Simultaneously, it is ensured that the good input performance of power inverter, it is to avoid to alternating current Net produces high-frequency harmonic pollution.The Traditional control strategy of grid side converter generally adopts double circle structure, wherein internal ring control base In grid voltage orientation, using linear control strategies such as PI controls the real-time regulation of electric current is realized.Dual feedback wind power generation system net Side converter belongs to nonlinear system, and linear control strategies remain deficiency when relevant control problem is processed, and control effect is depended on The problems such as parameter tuning, slow dynamic responding speed, becomes the bottleneck of system for restricting performance boost, in the urgent need to exploring Novel control Method meets the application demand for constantly being lifted to improve control characteristic.

PREDICTIVE CONTROL referred to according to system model the dynamic behaviour of predicting its future, and according to optimality principle selecting Most appropriate control action is selected, its Control platform and engineering practicability are obtained fully in fields such as Motor drive, power electronics Checking.However, the forecast Control Algorithm that the field adopts at present is mostly that, using on off state as optimized variable, power inverter is opened Pass frequency real-time change with the difference of operating mode, not only increases the design difficulty of filter inductance, and to the operation of commutator Performance is adversely affected；Additionally, the static control performance of system is generally poor, it is difficult to the application demand that satisfaction is increasingly lifted. Therefore, for the topological structure and operation characteristic of dual feedback wind power generation system grid side converter, new predictive control strategy is inquired into With important theory significance and engineering practical value.

The content of the invention

In order to overcome the deficiencies in the prior art, for construction featuress and the control of dual feedback wind power generation system grid side converter Demand, proposes that a kind of dual feedback wind power generation system grid side converter predicts Duty ratio control method, it is characterized in that, by voltage with Current sampling circuit obtains electrical network three-phase voltage value and three-phase electricity flow valuve, and two-phase rest frame is respectively obtained Jing after coordinate transform α, the beta -axis component of the trunnion axis α axles, vertical axises beta -axis component and current value of lower line voltage value；The α of magnitude of voltage, beta -axis component Jing phaselocked loops obtain line voltage real time phasor θ_s, based on the phase angle obtain line voltage d-axis d axles under two-phase rotating coordinate system, Quadrature axis q component u_gd、u_gqAnd current value d, q axle component i_d、i_q；According to system mathematic model and voltage, current value, respectively obtain Voltage vector V₁D, q shaft current rate of change δ under effect_d,1、δ_q,1, voltage vector V₂D, q shaft current rate of change δ under effect_d,2、 δ_q,2, voltage vector V₀D, q shaft current rate of change δ under effect_d,0、δ_q,0；Build voltage vector V₁Lower d, q shaft current of effect is one Individual sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1With three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship；Build electricity Pressure vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,2、e_q,2It is real-time with three-phase dutycycle Value d_a、d_b、d_cFunctional relationship；Build voltage vector V₀Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity is pre- Measured value e_d,0、e_q,0With three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship；Cost function is built based on control error prediction value g；Minimized based on cost function and obtain three-phase dutycycle value of calculation d_a'、d_b'、d_c', and then determined by the equivalent reconstruct of dutycycle Three-phase optimum dutycycle d_a″、d_b″、d_c″。

The voltage vector V₁D, q shaft current rate of change δ under effect_d,1、δ_q,1, voltage vector V₂D, q axle electricity under effect Rheology rate δ_d,2、δ_q,2, voltage vector V₀D, q shaft current rate of change δ under effect_d,0、δ_q,0Drawn by following formula：

In formula, L_g、R_gThe respectively inductance value and its equivalent resistance of filter inductance；V_1d、V_2d、V_0dVoltage vector is represented respectively V₁、V₂And zero vector V₀D axle components；V_1q、V_2q、V_0qVoltage vector V is represented respectively₁、V₂And zero vector V₀Q axle components.

The voltage vector V₁Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1With Three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,1=δ_d,1[(d_a-d_b)T_s]=δ_d,1[(1-d_b-d_c)T_s] (7)

e_q,1=δ_q,1[(d_a-d_b)T_s]=δ_q,1[(1-d_b-d_c)T_s] (8)

The voltage vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,2、e_q,2With Three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,2=δ_d,2[(d_b-d_c)T_s] (9)

e_q,2=δ_q,2[(d_b-d_c)T_s] (10)

The voltage vector V₀Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,0、e_q,0With Three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,0=2 δ_d,0d_cT_s (11)

e_q,0=2 δ_q,0d_cT_s (12)

The cost function g is drawn by following formula：

G=△ i_d ²+△i_q ² (13)

In formula, △ i_dWith △ i_qThe predictive value that d, q shaft current controls error is represented respectively, it is as follows：

In formula, i_dAnd i *_q* d, q shaft current reference value is represented respectively.

The three-phase dutycycle value of calculation d_a'、d_b'、d_c' should be able to ensure that cost function is minimum in real time, concrete calculating formula is such as Under：

d_c'=1-d_a (18)

In formula,

M=(δ_q,2-δ_q,0)δ_d,1-(δ_q,1-δ_q,0)δ_d,2-(δ_q,2-δ_q,1)δ_d,0 (19)

Three-phase optimum dutycycle d_a″、d_b″、d_c" it is both needed to meet more than 0 and less than 1, to d_a'、d_b'、d_c' be reconstructed Can obtain

Compared with the prior art, technical characterstic of the invention and effect：

The present invention relates to dual feedback wind power generation system grid side converter prediction Duty ratio control method.The method is based on double-fed The construction featuress and demand for control of wind generator system grid side converter, predict that different voltage vectors are made according to system mathematic model Curent change characteristic with, builds the cost function based on control error, with the single sampling period with reference to given value of current value The minimum constraints of cost function calculates dutycycle, and determines optimum dutycycle by equivalent reconstruct.The method is based on value Function minimization determines dutycycle, while ensureing that switching frequency is constant, effectively lifts dual feedback wind power generation system net side and becomes Parallel operation dynamic response rapidity and steady-state operation stationarity, realize the real-time optimized operation of system.

Description of the drawings

Fig. 1 dual feedback wind power generation system structure charts.

Fig. 2 dual feedback wind power generation system grid side converter voltage vector spatial distribution maps.

Fig. 3 dual feedback wind power generation system grid side converters of the present invention predict Duty ratio control structure chart.

Specific embodiment

Electrical network three-phase voltage value and three-phase electricity flow valuve are obtained by voltage and current sampling circuit, Jing after coordinate transform respectively Obtain α, β axle point of the trunnion axis of line voltage value under two-phase rest frame, vertical axises (α, β axle) component and current value Amount；The α of magnitude of voltage, beta -axis component Jing phaselocked loops obtain line voltage real time phasor θ_s, two cordic phase rotators are obtained based on the phase angle System lower line voltage d-axis, quadrature axis (d, q axle) component u_gd、u_gqAnd current value d, q axle component i_d、i_q；According to systematic mathematical mould Type and voltage, current value, respectively obtain voltage vector V₁D, q shaft current rate of change δ under effect_d,1、δ_q,1, voltage vector V₂Make D, q shaft current rate of change δ with_d,2、δ_q,2, voltage vector V₀D, q shaft current rate of change δ under effect_d,0、δ_q,0；Build electricity Pressure vector V₁Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1It is real-time with three-phase dutycycle Value d_a、d_b、d_cFunctional relationship；Build voltage vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity is pre- Measured value e_d,2、e_q,2With three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship；Build voltage vector V₀Lower d, q shaft current of effect In a sampling period T_sInterior variable quantity predictive value e_d,0、e_q,0With three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship；Base Cost function g is built in control error prediction value；Minimized based on cost function and obtain three-phase dutycycle value of calculation d_a'、d_b'、 d_c', and then three-phase optimum dutycycle d is determined by the equivalent reconstruct of dutycycle_a″、d_b″、d_c″。

The voltage vector V₁D, q shaft current rate of change δ under effect_d,1、δ_q,1, voltage vector V₂D, q axle electricity under effect Rheology rate δ_d,2、δ_q,2, voltage vector V₀D, q shaft current rate of change δ under effect_d,0、δ_q,0Drawn by following formula：

In formula, L_g、R_gThe respectively inductance value and its equivalent resistance of filter inductance；V_1d、V_2d、V_0dVoltage vector is represented respectively V₁、V₂And zero vector V₀D axle components；V_1q、V_2q、V_0qVoltage vector V is represented respectively₁、V₂And zero vector V₀Q axle components.

The voltage vector V₁Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1With Three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,1=δ_d,1[(d_a-d_b)T_s]=δ_d,1[(1-d_b-d_c)T_s] (7)

e_q,1=δ_q,1[(d_a-d_b)T_s]=δ_q,1[(1-d_b-d_c)T_s] (8)

The voltage vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,2、e_q,2With Three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,2=δ_d,2[(d_b-d_c)T_s] (9)

e_q,2=δ_q,2[(d_b-d_c)T_s] (10)

The voltage vector V₀Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,0、e_q,0With Three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,0=2 δ_d,0d_cT_s (11)

e_q,0=2 δ_q,0d_cT_s (12)

The cost function g is drawn by following formula：

G=△ i_d ²+△i_q ² (13)

In formula, △ i_dWith △ i_qD, q shaft current control error prediction value is represented respectively, it is as follows

In formula, i_dAnd i *_q* d, q shaft current reference value is represented respectively.

The three-phase dutycycle value of calculation d_a'、d_b'、d_c' should be able to ensure that cost function is minimum in real time, concrete calculating formula is such as Under：

d_c'=1-d_a (18)

In formula,

M=(δ_q,2-δ_q,0)δ_d,1-(δ_q,1-δ_q,0)δ_d,2-(δ_q,2-δ_q,1)δ_d,0 (19)

Three-phase optimum dutycycle d_a″、d_b″、d_c" it is both needed to meet more than 0 and less than 1, to d_a'、d_b'、d_c' be reconstructed Can obtain

The present invention is further described with reference to the accompanying drawings and detailed description.

Using Motor convention, the mathematical model of dual feedback wind power generation system grid side converter can under two-phase rest frame To be written as

In formula, i_α、i_βRespectively electric current α, beta -axis component；u_gα、u_gβRespectively line voltage α, beta -axis component；u_cα、u_cβRespectively For grid side converter AC output voltage α, beta -axis component；L_g、R_gThe respectively inductance value and its equivalent resistance of filter inductance.

The mathematical model of dual feedback wind power generation system grid side converter can be written as under rotating coordinate system

In formula, subscript d, q represents respectively d, q axle component of correspondence electric parameters；ω_gFor electrical network angular frequency.

Current changing rate can be write out according to above formula, it is as follows

In the implementation procedure of prediction Duty ratio control algorithm, neighbouring vectors V is chosen₁And V₂As calculating vector, now three Relation between phase dutycycle instantaneous value is d_a>d_b>d_c.In a sampling period T_sIn, voltage vector V₁Action time be (d_a- d_b)T_s=(1-d_b-d_c)T_s, voltage vector V₂Action time be (d_b-d_c)T_s, as shown in Figure 2.Thus zero vector can be calculated Action time be T_s-(1-d_b-d_c)T_s-(d_b-d_c)T_s=2d_cT_s。

According to formula (5) and formula (6), voltage vector V can be respectively write out₁And V₂Current changing rate under effect, is distinguished It is expressed as

In formula, δ_d,1、δ_q,1Respectively voltage vector V₁D, q shaft current rate of change under effect；δ_d,2、δ_q,2Respectively voltage Vector V₂D, q shaft current rate of change under effect；δ_d,0、δ_q,0Respectively voltage vector V₀D, q shaft current rate of change under effect.

Voltage vector V₁Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1Can be respectively It is written as

e_d,1=δ_d,1[(d_a-d_b)T_s]=δ_d,1[(1-d_b-d_c)T_s] (35)

e_q,1=δ_q,1[(d_a-d_b)T_s]=δ_q,1[(1-d_b-d_c)T_s] (36)

Voltage vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,2、e_q,2Can be respectively It is written as

e_d,2=δ_d,2[(d_b-d_c)T_s] (37)

e_q,2=δ_q,2[(d_b-d_c)T_s] (38)

Voltage vector V₀Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,0、e_q,0Can be respectively It is written as

e_d,0=2 δ_d,0d_cT_s (39)

e_q,0=2 δ_q,0d_cT_s (40)

According to above-mentioned amount, d, q shaft current control error prediction value △ i can be obtained_dWith △ i_qFor

In formula, i_d ^*And i_q ^*D, q shaft current reference value is represented respectively.

According to the demand for control of grid side converter, construction cost function is as follows

G=△ i_d ²+△i_q ² (43)

The three-phase dutycycle value of calculation d of grid side converter_a'、d_b'、d_c' should be able to ensure that cost function is minimum in real time, specifically Calculating formula is as follows

d_c'=1-d_a (46)

In formula,

M=(δ_q,2-δ_q,0)δ_d,1-(δ_q,1-δ_q,0)δ_d,2-(δ_q,2-δ_q,1)δ_d,0 (47)

In grid side converter running, three-phase optimum dutycycle d_a″、d_b″、d_c" it is both needed to meet more than 0 and less than 1. Accordingly, it would be desirable to three-phase dutycycle value of calculation d_a'、d_b'、d_c' equivalent reconstruct is done, the three-phase optimum dutycycle calculating formula for drawing is such as Under

Dual feedback wind power generation system grid side converter prediction Duty ratio control structure of the present invention is as shown in Figure 3.

Claims (8)

1. a kind of dual feedback wind power generation system grid side converter predicts Duty ratio control method, it is characterized in that, by voltage and electricity Stream sample circuit obtains electrical network three-phase voltage value and three-phase electricity flow valuve, respectively obtains under two-phase rest frame Jing after coordinate transform α, the beta -axis component of the trunnion axis α axles, vertical axises β components and current value of line voltage value；α, the beta -axis component Jing lock of magnitude of voltage Phase ring obtains line voltage real time phasor θ_s, based on the phase angle obtain line voltage d-axis under two-phase rotating coordinate system, quadrature axis (d, Q axles) component u_gd、u_gqAnd current value d, q axle component i_d、i_q；According to system mathematic model and voltage, current value, respectively obtain Voltage vector V₁D, q shaft current rate of change δ under effect_d,1、δ_q,1, voltage vector V₂D, q shaft current rate of change δ under effect_d,2、 δ_q,2, voltage zero vector V₀D, q shaft current rate of change δ under effect_d,0、δ_q,0；Build voltage vector V₁Lower d, q shaft current of effect exists One sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1With three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship；Build Voltage vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,2、e_q,2With three-phase dutycycle reality Duration d_a、d_b、d_cFunctional relationship；Build voltage zero vector V₀Lower d, q shaft current of effect is in a sampling period T_sInterior change Amount predictive value e_d,0、e_q,0With three-phase dutycycle instantaneous value d_a、d_b、d_cFunctional relationship；Value is built based on control error prediction value Function g；Minimized based on cost function and obtain three-phase dutycycle value of calculation d_a'、d_b'、d_c', and then by the equivalent reconstruct of dutycycle Determine three-phase optimum dutycycle d_a”、d_b”、d_c”。

2. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, The voltage vector V₁D, q shaft current rate of change δ under effect_d,1、δ_q,1, voltage vector V₂D, q shaft current rate of change under effect δ_d,2、δ_q,2, voltage zero vector V₀D, q shaft current rate of change δ under effect_d,0、δ_q,0Drawn by following formula：

${\mathrm{\δ}}_{d,1}=\frac{{\mathrm{di}}_d}{dt}{|}_{V=V_1}=\frac{1}{L_g}(-R_g{i}_d+{\mathrm{\ω}}_g{L}_g{i}_q-V_{1d}+u_{gd})---\left(1\right)$

${\mathrm{\δ}}_{d,2}=\frac{{\mathrm{di}}_d}{dt}{|}_{V=V_2}=\frac{1}{L_g}(-R_g{i}_d+{\mathrm{\ω}}_g{L}_g{i}_q-V_{2d}+u_{gd})---\left(2\right)$

${\mathrm{\δ}}_{d,0}=\frac{{\mathrm{di}}_d}{dt}{|}_{V=V_0}=\frac{1}{L_g}(-R_g{i}_d+{\mathrm{\ω}}_g{L}_g{i}_q-V_{0d}+u_{gd})---\left(3\right)$

${\mathrm{\δ}}_{q,1}=\frac{{\mathrm{di}}_q}{dt}{|}_{V=V_1}=\frac{1}{L_g}(-R_g{i}_q-{\mathrm{\ω}}_g{L}_g{i}_d-V_{1q}+u_{gq})---\left(4\right)$

${\mathrm{\δ}}_{q,2}=\frac{{\mathrm{di}}_q}{dt}{|}_{V=V_2}=\frac{1}{L_g}(-R_g{i}_q-{\mathrm{\ω}}_g{L}_g{i}_d-V_{2q}+u_{gq})---\left(5\right)$

${\mathrm{\δ}}_{q,0}=\frac{{\mathrm{di}}_q}{dt}{|}_{V=V_0}=\frac{1}{L_g}(-R_g{i}_q-{\mathrm{\ω}}_g{L}_g{i}_d-V_{0q}+u_{gq})---\left(6\right)$

In formula, L_g、R_gThe respectively inductance value and its equivalent resistance of filter inductance；V_1d、V_2d、V_0dVoltage vector V is represented respectively₁、V₂ And zero vector V₀D axle components；V_1q、V_2q、V_0qVoltage vector V is represented respectively₁、V₂And zero vector V₀Q axle components, ω_gFor electrical network Angular frequency.

3. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, The voltage vector V₁Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,1、e_q,1With three-phase duty Than instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,1=δ_d,1[(d_a-d_b)T_s]=δ_d,1[(1-d_b-d_c)T_s] (7)

e_q,1=δ_q,1[(d_a-d_b)T_s]=δ_q,1[(1-d_b-d_c)T_s] (8)。

4. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, The voltage vector V₂Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,2、e_q,2With three-phase duty Than instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,2=δ_d,2[(d_b-d_c)T_s] (9)

e_q,2=δ_q,2[(d_b-d_c)T_s] (10)。

5. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, The voltage zero vector V₀Lower d, q shaft current of effect is in a sampling period T_sInterior variable quantity predictive value e_d,0、e_q,0Account for three-phase Sky is than instantaneous value d_a、d_b、d_cFunctional relationship drawn by following formula：

e_d,0=2 δ_d,0d_cT_s (11)

e_q,0=2 δ_q,0d_cT_s (12)。

6. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, The cost function g is drawn by following formula：

G=Δ i_d ²+Δi_q ² (13)

In formula, Δ i_dWith Δ i_qThe predictive value that d, q shaft current controls error is represented respectively, it is as follows

${\mathrm{\Δi}}_d=i_d^{*}-i_d-e_{d,0}-e_{d,1}-e_{d,2}---\left(14\right)$

${\mathrm{\Δi}}_q=i_q^{*}-i_q-e_{q,0}-e_{q,1}-e_{q,2}---\left(15\right)$

In formula,WithD, q shaft current reference value is represented respectively.

7. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, The three-phase dutycycle value of calculation d '_a、d′_b、d′_cShould be able to ensure that cost function is minimum in real time, concrete calculating formula is as follows：

$d_a^{\′}=\frac{1}{2{\mathrm{mT}}_s}\[{\mathrm{\Δi}}_d({\mathrm{\δ}}_{q,2}-{\mathrm{\δ}}_{q,1})+{\mathrm{\Δi}}_q({\mathrm{\δ}}_{d,1}-{\mathrm{\δ}}_{d,2})+2T_s{\mathrm{\δ}}_{q,0}({\mathrm{\δ}}_{d,2}-{\mathrm{\δ}}_{d,1})-2T_s{\mathrm{\δ}}_{d,0}({\mathrm{\δ}}_{q,2}-{\mathrm{\δ}}_{q,1})+T_s{\mathrm{\δ}}_{d,1}{\mathrm{\δ}}_{q,2}-T_s{\mathrm{\δ}}_{d,2}{\mathrm{\δ}}_{q,1})\]---\left(16\right)$

$d_b^{\′}=\frac{1}{2{\mathrm{mT}}_s}\[{\mathrm{\Δi}}_d(2{\mathrm{\δ}}_{q,0}-{\mathrm{\δ}}_{q,1}-{\mathrm{\δ}}_{q,2})+{\mathrm{\Δi}}_q({\mathrm{\δ}}_{d,1}+{\mathrm{\δ}}_{d,2}-2{\mathrm{\δ}}_{d,0})+T_s{\mathrm{\δ}}_{q,1}(2{\mathrm{\δ}}_{d,0}-{\mathrm{\δ}}_{d,2})+T_s{\mathrm{\δ}}_{d,1}({\mathrm{\δ}}_{q,2}-2{\mathrm{\δ}}_{q,0})\]---\left(17\right)$

d′_c=1-d_a (18)

In formula,

M=(δ_q,2-δ_q,0)δ_d,1-(δ_q,1-δ_q,0)δ_d,2-(δ_q,2-δ_q,1)δ_d,0 (19)

Δi_dWith Δ i_qThe predictive value that d, q shaft current controls error is represented respectively.

8. dual feedback wind power generation system grid side converter as claimed in claim 1 predicts Duty ratio control method, it is characterized in that, Three-phase optimum dutycycle d_a”、d_b”、d_c" be both needed to meet more than 0 and less than 1, to d '_a、d′_b、d′_cBeing reconstructed to obtain

$d_a^{\′\′}=d_a^{\′}-\min (d_a^{\′},d_b^{\′},d_c^{\′})+\frac{1-max(d_a^{\′},d_b^{\′},d_c^{\′})+\min (d_a^{\′},d_b^{\′},d_c^{\′})}{2}---\left(20\right)$

$d_b^{\′\′}=d_b^{\′}-\min (d_a^{\′},d_b^{\′},d_c^{\′})+\frac{1-max(d_a^{\′},d_b^{\′},d_c^{\′})+\min (d_a^{\′},d_b^{\′},d_c^{\′})}{2}---\left(21\right)$

$d_c^{\′\′}=d_c^{\′}-\min (d_a^{\′},d_b^{\′},d_c^{\′})+\frac{1-max(d_a^{\′},d_b^{\′},d_c^{\′})+\min (d_a^{\′},d_b^{\′},d_c^{\′})}{2}---\left(22\right).$