CN103427738A - Optimal predictive direct power control method of doubly fed induction generator - Google Patents

Abstract

The invention discloses an optimal predicative direct power control method of a doubly fed induction generator. The method includes the steps that two effective voltage vectors and one zero vector are applied in each control period, one voltage vector is selected to obtain a switching list according to the predicted change conditions of active power and reactive power and the stator flux linkage positions when different control behaviors are applied, and the action time of the selected voltage vector is calculated according to the power tolerance minimum principle in the control periods; when the action time of the voltage vector obtained through calculation is negative, the voltage vectors are reselected to calculate the action time. Therefore, accuracy and effectiveness of the selected voltage vectors and the action time are guaranteed, and the active power and the reactive power of a doubly fed power generating system are independently and effectively controlled. By the adoption of the optimal predicative direct power control method, low-order current harmonics can be reduced, constant switching frequency is achieved without converting rotational coordinates and modulating the space vector pulse width, and rapid dynamic response and good steady-state performance are possessed.

Description

A kind of double fed induction generators Optimization Prediction direct Power Control method

Technical field

The present invention relates to the PWM control method of double fed asynchronous wind power generator rotor side voltage source converter in a kind of wind power generation field, particularly a kind of double-fed asynchronous wind generator system prediction direct Power Control method.

Background technology

Modern large-scale wind powered generation syst mainly adopts two types of double-fed asynchronous generator (DFIG) and magneto alternators, for the raising generating efficiency, all adopts the variable speed constant frequency generator operational mode.Wherein, at most, technology is the most ripe, is current mainstream model in the DFIG application.The double-fed wind generating scheme can realize that variable speed constant frequency controls, and reduces the capacity of converter, also can realize gaining merit, idle decoupling zero controls, and can export corresponding perception or capacitive reactive power according to the requirement of electrical network, and the flexibility of this idle control is highly beneficial to electrical network.Vector control (VC) and direct Power Control (DPC) are the control strategies of dual feedback wind power generation system main flow always.Vector control can realize the independent regulation of active power and reactive power, obtains good steady-state behaviour, but needs comparatively complicated same leg speed rotating coordinate transformation and the phase information of line voltage, the parameter tuning complexity of pi regulator, and dynamic property is slightly poor.The direct Power Control (LUT-DPC) of tradition based on switch list is without same leg speed rotating coordinate transformation, control structure is simple, dynamic response is fast, but need carry out stagnant chain rate and the Stator flux linkage sectors judgement, system power fluctuates larger, and the steady-state behaviour of the method haves much room for improvement.Prediction direct Power Control (P-DPC) technology, because it can have stable state and dynamic property preferably in the situation that realize that without space vector modulation module SVM switching frequency is constant, be considered to a kind of DPC strategy that has much potentiality.But the difficult point of P-DPC is determining of the selection of effective voltage vector and each effective vector action time, and its voltage vector action time that may occur be that negative situation can be brought adverse influence to control.Above control method or aspect the system dynamic response or certain defect is being arranged aspect steady operation can not reach desirable effect simultaneously, and the further investigation of therefore the P-DPC implementation method of double fed induction generators being carried out has important practical significance.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art, a kind of Optimization Prediction direct Power Control method of dual-feed asynchronous wind power generator is provided.The inventive method is compared traditional control method, and without increasing additional hardware, and control structure is very simple, can reach dynamic property and stable state accuracy preferably.

Technical solution of the present invention, a kind of double fed asynchronous wind power generator rotor side converter Optimization Prediction direct Power Control method, it is characterized in that, described rotor-side converter Optimization Prediction direct Power Control method, on the basis of the power Mathematical Modeling of DFIG rotor-side converter and Classical forecast direct Power Control method, selection strategy and action time to space vector of voltage are optimized in processing, avoided vector action time to occur the situation of negative value, can regulate rapidly meritorious, reactive power, obtain good static properties;

The Optimization Prediction direct Power Control method of described double fed asynchronous wind power generator rotor side converter comprises the following steps:

1. a double fed asynchronous wind power generator rotor side converter Optimization Prediction direct Power Control method is characterized in that comprising the following steps:

(1) utilize three voltage hall sensors (3) to gather dual-feed asynchronous wind power generator DFIG(1) threephase stator voltage signal U _SabcUtilize three-phase current Hall element (4) to gather threephase stator current signal I _Sabc

(2) by the threephase stator voltage signal U collected _SabcDetect the angular frequency that obtains stator voltage through phase-locked loop (9) _sAnd phase theta _sIn this, adopt encoder (5) to detect the rotor position of DFIG simultaneously _r, then pass through differentiator (6) and calculate rotational speed omega _rAnd calculate the slippage angular frequency by subtracter _Slip=ω _s-ω _r

(3) by the threephase stator voltage signal U collected _SabcWith threephase stator current signal I _SabcTo two-phase coordinate transformation module (7), obtain the stator voltage vector U under stator coordinate through static three-phase _{S α β}With stator current vector I _{S α β}

(4) by the stator voltage vector U obtained _{S α β}, stator current vector I _{S α β}Calculate meritorious, the reactive power signals P of stator output by power computation module (10) _s, Q _s, and this value and stator is meritorious, reactive power reference qref P _ref, Q _refCompare by module (11), gained merit, the deviation P of reactive power _Error, Q _Error

(5) by the stator voltage vector U obtained _{S α β}Obtain the stator magnetic linkage Ψ under stator two-phase rest frame through flux linkage calculation module (8) _{S α β}, and according to the rotor position of DFIG _rObtain the stator magnetic linkage under rotor two-phase rotating coordinate system through rotating coordinate transformation module (12)

(6) to the stator magnetic linkage under the rotor two-phase rotating coordinate system obtained

Carry out sector judgement (13), query optimization P-DPC switch list (14) according to this, two effective voltage vector V that controlled cycle internal rotor side converter should be exported _a, V _bWith a zero vector V _Zero

(7) the voltage vector V that will table look-up and obtain _a, V _b, V _ZeroCalculate meritorious, the reactive power rate of change Δ P caused separately through power variation rate computing module (15) _a, Δ P _b, Δ P _ZeroΔ and Δ Q _a, Δ Q _b, Δ Q _Zero

(8) according to meritorious, the reactive power rate of change Δ P that obtain _a, Δ P _b, Δ P _ZeroΔ and Δ Q _a, Δ Q _b, Δ Q _ZeroWith deviation P meritorious, reactive power _Error, Q _Error, take gain merit, reactive power deviation minimum be to be controlled target, by optimizing vector computing module action time (16), obtains rotor-side converter switches signal S _a, S _b, S _c

(9) by the rotor-side converter switches signal S obtained _a, S _b, S _cDrive IGBT through driver module, realize the Optimization Prediction direct Power Control.

The invention has the beneficial effects as follows, can improve the control of DFIG conventional vector and each the comfortable dynamic property of direct Power Control based on switch list or the defect on steady-state behaviour, and routine prediction direct Power Control has been carried out to effective improvement, can greatly reduce because of not to occurring that vector effectively processes for negative situation the low order current harmonics caused action time.This method control structure is very simple, without complicated coordinate transform and controller parameter, adjusts, without space vector pulse width modulation, can realize that switching frequency is constant, reduce the DFIG output-power fluctuation, reduce the harmonic content of electric current, there is fast dynamic response and good steady-state behaviour.

The accompanying drawing explanation

Fig. 1 is double fed asynchronous wind power generator rotor side converter Optimization Prediction direct Power Control block diagram;

Fig. 2 is the division figure of eight kinds of space vector of voltage and 12 sectors;

Fig. 3 is rate of change figure meritorious during the stator magnetic linkage diverse location under eight kinds of voltage vector effects, reactive power;

Fig. 4 is distribution diagram action time of three voltage vectors in control cycle;

Fig. 5 is the power step waveform simulated effect figure of DFIG rotor-side converter using Optimization Prediction direct Power Control (optimizing P-DPC), is followed successively by from top to bottom the active power of stator output in figure, reactive power, stator three-phase current, rotor three-phase electric current;

Fig. 6 is that DFIG rotor-side converter using conventional vector is controlled the power step waveform simulated effect figure of (VC), is followed successively by from top to bottom the active power of stator output in figure, reactive power, stator three-phase current, rotor three-phase electric current;

Fig. 7 is the power step waveform simulated effect figure of the direct Power Control (LUT-DPC) of DFIG rotor-side converter using based on switch list, is followed successively by from top to bottom the active power of stator output in figure, reactive power, stator three-phase current, rotor three-phase electric current;

Fig. 8 is the spectrum analysis figure of the lower stator A phase current of DFIG rotor-side converter using Optimization Prediction direct Power Control (optimizing P-DPC);

Fig. 9 is the spectrum analysis figure of the lower stator A phase current of DFIG rotor-side converter using conventional prediction direct Power Control (P-DPC).

Embodiment

Below in conjunction with accompanying drawing and case study on implementation, the present invention is further described, and purpose of the present invention and effect will be more obvious.

Fig. 1 is the schematic diagram of a kind of dual-feed asynchronous wind power generator Optimization Prediction direct Power Control method of proposing of the present invention.The double-fed induction wind driven generator (DFIG) 1 that comprises a 2MW of control object, the rotor-side converter 2 formed by three-phase bridge IGBT be connected with DFIG rotor winding, for detection of the voltage sensor 3 of DFIG stator three-phase voltage with for detection of the current Hall transducer 4 of DFIG stator three-phase current, for detection of the encoder 5 of DFIG rotor position angle, obtain the differentiator 6 of generating unit speed and realize the control loop that DFIG output is meritorious, reactive power is predicted and regulated.Control loop consists of feedback signal treatment channel and forward direction control channel, wherein the feedback signal treatment channel comprises the three-phase of stator voltage for obtaining stator two-phase rest frame, stator current vector signal/two-phase static coordinate conversion module 7, stator magnetic linkage Observation Blocks 8, digital phase-locked loop module 9, power computation module 10 and power comparison module 11; Forward direction control channel comprises the rotating coordinate transformation module 12 of obtaining stator two-phase magnetic linkage signal under the stationary rotor coordinate system, and module 13 is selected in sector, optimizes switch list module 14, power variation rate computing module 15, and optimize vector computing module action time 16.

Described dual-feed asynchronous wind power generator Optimization Prediction direct Power Control method comprises the following steps:

(1) utilize three voltage hall sensors 3 to gather dual-feed asynchronous wind power generator DFIG1 threephase stator voltage signal U _SabcUtilize three-phase current Hall element 4 to gather threephase stator current signal I _Sabc

(2) by the threephase stator voltage signal U collected _SabcDetect through phase-locked loop 9 angular frequency that obtains stator voltage _sAnd phase theta _sMeanwhile adopt encoder 5 to detect the rotor position of DFIG _r, then calculate rotational speed omega through differentiator 6 _rAnd calculate the slippage angular frequency by subtracter _Slip=ω _s-ω _r

(3) by the threephase stator voltage signal U collected _SabcWith threephase stator current signal I _SabcTo two-phase coordinate transformation module 7, obtain the stator voltage vector U under stator coordinate through static three-phase _{S α β}With stator current vector I _{S α β}Take stator voltage as example, and the expression formula from static three-phase to the two-phase coordinate transform is:

$\left[\begin{array}{c}{U}_{\mathrm{s\α}}\\ U_{\mathrm{s\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{U}_{\mathrm{sa}}\\ U_{\mathrm{sb}}\\ U_{\mathrm{sc}}\end{array}\right]---\left(1\right)$

$\left[\begin{array}{c}{I}_{\mathrm{s\α}}\\ I_{\mathrm{s\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{I}_{\mathrm{sa}}\\ I_{\mathrm{sb}}\\ I_{\mathrm{sc}}\end{array}\right]---\left(2\right)$

Wherein, U _{S α}, U _{S β}For stator voltage vector U _{S α β}Component on static two-phase α, β axle, I _{S α}, I _{S β}For stator current vector I _{S α β}Component on static two-phase α, β axle, U _Sa, U _Sb, U _ScFor threephase stator voltage signal U _SabcA, b, c phase voltage, I _Sa, I _Sb, I _ScFor threephase stator current signal I _SabcA, b, c phase current.

(4) by the stator voltage vector U collected _{S α β}, stator current vector I _{S α β}Calculate meritorious, the reactive power signals P of stator output by rotor-side power computation module 10 _s, Q _s, meritorious, reactive power is calculated formula and is:

$P_s=-\frac{3}{2}[U_{\mathrm{s\α}}{I}_{\mathrm{s\α}}+U_{\mathrm{s\β}}{I}_{\mathrm{s\β}}]$

$Q_s=-\frac{3}{2}[-U_{\mathrm{s\α}}{I}_{\mathrm{s\β}}+U_{\mathrm{s\β}}{I}_{\mathrm{s\α}}]---\left(3\right)$

(5) stator that will obtain according to (3) step is to meritorious, the reactive power signals P of electrical network output _s, Q _s, reactive power reference qref P meritorious with given stator _ref, Q _refBy module 11, compare, output is meritorious, the deviation P of reactive power _Error, Q _Error:

P _error=P _ref-P _s

Q _error=Q _ref-Q _s （4）

(6) stator voltage vector U sampling obtained _{S α β}Calculate the stator magnetic linkage Ψ under stator two-phase rest frame through stator magnetic linkage computing module 8 _{S α β}Ignore the impact of stator resistance, stator magnetic linkage can be expressed as:

Ψ _sαβ=∫U _sαβdt （5）

(7) rotor position of the DFIG detected according to step (2) _r, by the stator magnetic linkage Ψ under stator two-phase rest frame _{S α β}Obtain the stator magnetic linkage under rotor two phase coordinate systems by rotating coordinate transformation module 12

The conversion expression formula that is tied to rotor two-phase rotating coordinate system from stator two-phase static coordinate is:

$\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{s\α}}^r\\ {\mathrm{\ψ}}_{\mathrm{s\β}}^r\end{array}\right]=\left[\begin{array}{cc}\cos {\mathrm{\θ}}_r& \sin {\mathrm{\θ}}_r\\ -\sin {\mathrm{\θ}}_r& \cos {\mathrm{\θ}}_r\end{array}\right]\left[\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{s\α}}\\ {\mathrm{\ψ}}_{\mathrm{s\β}}\end{array}\right]---\left(6\right)$

Wherein,

For the stator magnetic linkage under rotor two phase coordinate systems Component on rotor two-phase α, β axle, ψ _{S α}, ψ _{S β}For the stator magnetic linkage Ψ under stator two-phase rest frame _{S α β}Component on stator two-phase α, β axle;

(8) stator magnetic linkage under the rotor two-phase rotating coordinate system obtained according to step (6)

Through sector judge module 13 judgement place sector number SectNo, sector is divided as shown in Figure 2; Query optimization P-DPC switch list according to this again, according to V _bT action time of vector _bBe greater than zero choosing in control cycle and apply two effective voltage vector V _a, V _bWith a zero vector V _ZeroOptimize the P-DPC switch list as follows:

Optimize the P-DPC switch list

(9) will inquire about the voltage vector V applied in the control cycle that switch list obtains _a, V _b, V _ZeroBy power variation rate computing module 15, calculate respectively because of V _a, V _b, V _ZeroCaused meritorious, reactive power rate of change Δ P _a, Δ P _b, Δ P _ZeroAnd Δ Q _a, Δ Q _b, Δ Q _ZeroIgnore rotor resistance, its calculating formula is:

$\left[\begin{array}{c}{\mathrm{\&Delta;P}}_k\\ {\mathrm{\&Delta;Q}}_k\end{array}\right]=\left[\begin{array}{cc}-{\mathrm{\&delta;L}}_r{R}_s& -{\mathrm{\&omega;}}_{\mathrm{slip}}\\ {\mathrm{\&omega;}}_{\mathrm{slip}}& -{\mathrm{\&delta;L}}_r{R}_s\end{array}\right]\left[\begin{array}{c}{P}_s\\ Q_s\end{array}\right]+\frac{{3\mathrm{\&delta;L}}_m}{2}\left[\begin{array}{cc}-U_{\mathrm{s\&alpha;}}& -U_{\mathrm{s\&beta;}}\\ -U_{\mathrm{s\&beta;}}& U_{\mathrm{s\&alpha;}}\end{array}\right]\left[\begin{array}{c}{V}_{\mathrm{k\&alpha;}}\\ V_{\mathrm{k\&beta;}}\end{array}\right]+\frac{3s{\mathrm{\&delta;<figure-callout\; id="2"\; label="L\; r"\; filenames="HDA0000371713850000011.png,HDA0000371713850000021.png"\; state="\{\{state\}\}">L</figure-callout>}}_r}{2}\left[\begin{array}{c}{\left|U_s\right|}^2\\ 0\end{array}\right]---\left(7\right)$

Wherein, R _sFor stator resistance, L _sFor stator inductance, L _rFor inductor rotor, L _mFor magnetizing inductance, T _sFor control cycle, $\mathrm{\&delta;}=\frac{1}{\mathrm{\&sigma;}{{\mathrm{<figure-callout\; id="2"\; label="L\; m"\; filenames="HDA0000371713850000011.png,HDA0000371713850000021.png"\; state="\{\{state\}\}">L</figure-callout>}}_m}^2},$ $\mathrm{\&sigma;}=1-\frac{L_s{L}_{\mathrm{<figure-callout\; id="2"\; label="r\; L\; m"\; filenames="HDA0000371713850000011.png,HDA0000371713850000021.png"\; state="\{\{state\}\}">r</figure-callout>}}}{{L_m}^{}},$ $\left|U\right|=\sqrt{{U_{\mathrm{s\&alpha;}}}^2+{U_{\mathrm{s\&beta;}}}^2},$ K=a, b, zero, Vk α, Vk β are the component of selected voltage vector on rotor two-phase α, β axle;

(10) meritorious, the reactive power rate of change Δ P that according to step (9), obtain _a, Δ P _b, Δ P _ZeroΔ and Δ Q _a, Δ Q _b, Δ Q _ZeroAnd the deviation P of meritorious, the reactive power that obtains of step (5) _Error, Q _Error, the calculating voltage vector V _a, V _b, V _ZeroAction time:

$\left\{\begin{array}{c}{T}_a=\frac{({\mathrm{\&Delta;Q}}_b-{\mathrm{\&Delta;Q}}_{\mathrm{zero}})\&times;P_{\mathrm{error}}+({\mathrm{\&Delta;P}}_{\mathrm{zero}}-{\mathrm{\&Delta;P}}_b)\&times;Q_{\mathrm{error}}+({\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_{\mathrm{zero}})\&times;T_s}{{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_b+{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_{\mathrm{zero}}+{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_a-{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_{\mathrm{zero}}-{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_a}\\ T_b=\frac{({\mathrm{\&Delta;Q}}_{\mathrm{zero}}-{\mathrm{\&Delta;Q}}_b)\&times;P_{\mathrm{error}}+({\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;P}}_{\mathrm{zero}})\&times;Q_{\mathrm{error}}+(-{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_a+{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_{\mathrm{zero}})\&times;T_s}{{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_b+{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_{\mathrm{zero}}+{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_a-{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_{\mathrm{zero}}-{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_a}\\ T_{\mathrm{zero}}=T_s-T_a-T_b\end{array}\right.---\left(8\right)$

Wherein, T _a, T _b, T _ZeroFor selected vector corresponding action time, T _sFor control cycle; Vector T action time that formula calculates thus _a, T _b, T _ZeroConverted quantity Δ P, the Δ Q that makes active power total in control cycle and total reactive power be equal to gain merit, the deviation P of reactive power _Error, Q _Error, meritorious when control cycle finishes, reactive power will equal that given stator is meritorious, reactive power reference qref P _ref, Q _ref

Converted quantity Δ P, the Δ Q of total active power and total reactive power are in control cycle:

$\left\{\begin{array}{c}\mathrm{\&Delta;P}={\mathrm{\&Delta;P}}_a\&times;T_a+{\mathrm{\&Delta;P}}_b\&times;T_b+{\mathrm{\&Delta;P}}_{\mathrm{zero}}\&times;T_{\mathrm{zero}}\\ \mathrm{\&Delta;Q}={\mathrm{\&Delta;Q}}_a\&times;T_a+{\mathrm{\&Delta;Q}}_b\&times;T_b+{\mathrm{\&Delta;Q}}_{\mathrm{zero}}\&times;T_{\mathrm{zero}}\end{array}\right.$

(11) according to above formula, calculate when T occurring _b<0 o'clock, query optimization P-DPC switch list reselected voltage vector V again _b, action time is calculated in repeating step (9), (10), now will T can not occur again _b<0 situation.

(12) according to voltage vector V _a, V _b, V _ZeroThe switching signal S of controlled cycle internal rotor side converter _a, S _b, S _cAnd according to vector T action time calculated _a, T _b, T _ZeroAccording to Fig. 4 dispense switch signal S _a, S _b, S _cThe output period; Vector V ₀Switching signal (S _a, S _b, S _c) be (0,0,0), vector V ₁Switching signal (S _a, S _b, S _c) be (1,0,0), vector V ₂Switching signal (S _a, S _b, S _c) be (1,1,0), vector V ₃Switching signal (S _a, S _b, S _c) be (0,1,0), vector V ₄Switching signal (S _a, S _b, S _c) be (0,1,1), vector V ₅Switching signal (S _a, S _b, S _c) be (0,0,1), vector V ₆Switching signal (S _a, S _b, S _c) be (1,0,1), vector V ₇Switching signal (S _a, S _b, S _c) be (1,1,1);

(13) by the rotor-side converter switches signal S obtained _a, S _b, S _cThrough driver module, drive IGBT to realize the Optimization Prediction direct Power Control.

With reference to Fig. 5,6,7, can find out that DFIG is to optimize under the P-DPC method active power and reactive power dynamic response time extremely short, there is the quick dynamic property approximate with the LUT-DPC method, and during stable state, power is steady, current sinusoidal, no matter have the steady-state behaviour approximate with the VC method, improved the defect on each comfortable dynamic property of VC and LUT-DPC or steady-state behaviour, be dynamically or on steady-state behaviour can reach gratifying effect.

With reference to 8,9, can find out, adopt optimization P-DPC can greatly reduce low-order harmonic content in electric current, harmonic wave mainly concentrates near switching frequency, can realize fixing switching frequency.

In sum, optimization P-DPC method control structure disclosed by the invention is very simple, without carrying out complicated coordinate transform and controller parameter, adjust, employing reselects the method for vector and has effectively eliminated electric current low-order harmonic composition, can realize that dual-feed asynchronous wind power generator is meritorious, independent, effective control of reactive power, guarantee steady output and the quality of power supply meritorious, reactive power, there is future in engineering applications comparatively widely.

Claims (3)

1. a double fed asynchronous wind power generator rotor side converter Optimization Prediction direct Power Control method is characterized in that comprising the following steps:

(1) utilize three voltage hall sensors (3) to gather dual-feed asynchronous wind power generator DFIG(1) threephase stator voltage signal U _SabcUtilize three-phase current Hall element (4) to gather threephase stator current signal I _Sabc

(2) by the threephase stator voltage signal U collected _SabcDetect the angular frequency that obtains stator voltage through phase-locked loop (9) _sAnd phase theta _sAdopt encoder (5) to detect the rotor position of DFIG simultaneously _r, then pass through differentiator (6) and calculate rotational speed omega _rAnd calculate the slippage angular frequency by subtracter _Slip=ω _s-ω _r

(3) by the threephase stator voltage signal U collected _SabcWith threephase stator current signal I _SabcTo two-phase coordinate transformation module (7), obtain the stator voltage vector U under stator coordinate through static three-phase _{S α β}With stator current vector I _{S α β}

(4) by the stator voltage vector U obtained _{S α β}, stator current vector I _{S α β}Calculate meritorious, the reactive power signals P of stator output by power computation module (10) _s, Q _s, and this value and stator is meritorious, reactive power reference qref P _ref, Q _refCompare by module (11), gained merit, the deviation P of reactive power _Error, Q _Error

(5) by the stator voltage vector U obtained _{S α β}Obtain the stator magnetic linkage Ψ under stator two-phase rest frame through flux linkage calculation module (8) _{S α β}, and according to the rotor position of DFIG _rObtain the stator magnetic linkage under rotor two-phase rotating coordinate system through rotating coordinate transformation module (12)

(6) to the stator magnetic linkage under the rotor two-phase rotating coordinate system obtained

Carry out sector judgement (13), query optimization P-DPC switch list (14) according to this, two effective voltage vector V that controlled cycle internal rotor side converter should be exported _a, V _bWith a zero vector V _Zero

(7) the voltage vector V that will table look-up and obtain _a, V _b, V _ZeroCalculate meritorious, the reactive power rate of change Δ P caused separately through power variation rate computing module (15) _a, Δ P _b, Δ P _ZeroΔ and Δ Q _a, Δ Q _b, Δ Q _Zero

(8) according to meritorious, the reactive power rate of change Δ P that obtain _a, Δ P _b, Δ P _ZeroΔ and Δ Q _a, Δ Q _b, Δ Q _ZeroWith deviation P meritorious, reactive power _Error, Q _Error, take gain merit, reactive power deviation minimum be to be controlled target, by optimizing vector computing module action time (16), obtains rotor-side converter switches signal S _a, S _b, S _c

(9) by the rotor-side converter switches signal S obtained _a, S _b, S _cDrive IGBT through driver module, realize the Optimization Prediction direct Power Control.

2. the optimization P-DPC method of a kind of dual-feed asynchronous wind power generator according to claim 1, is characterized in that, in described step (6), optimizes P-DPC switch list deterministic process as follows:

(6.1) the voltage vector plane under rotor coordinate on average is subdivided into to 12 sectors, as shown in Figure 2, and, according to meritorious, idle rate of change under eight kinds of voltage vectors of stator magnetic linkage position analysis, as shown in Figure 3, choose the suitable voltage vector that each sector applies; Voltage vector selection principle: the vector that makes meritorious and idle increase should be arranged in a control cycle, also will have and make meritorious and the idle vector reduced, two effective vector V _a, V _bFor adjacent vector, zero vector V _ZeroMeet minimum switching loss principle, select effective vector that the active power rate of change is larger as master vector V _a, the auxiliary vector V of less conduct _b, P-DPC switch list accordingly tentatively is optimized;

(6.2) choose vector according to above principle, there will be stator magnetic linkage selected three situations that voltage vector all makes reactive power reduce when the end of even number sector, make and calculate V _bT action time of vector _bBe less than zero, now reselect V _aThe adjacent vector of side is as new V counterclockwise _b, obtain complete optimization P-DPC switch list; Optimize the P-DPC switch list as follows:

Optimize the P-DPC switch list

3. the optimization P-DPC method of a kind of dual-feed asynchronous wind power generator according to claim 1, is characterized in that, in described step (8), optimizes vector computing module action time (16) at first according to optimizing P-DPC switch list V _bT action time of vector _bBe greater than zero and choose the voltage vector applied in control cycle, then calculate control cycle T _sInterior each voltage vector V _a, V _b, V _ZeroT action time _a, T _b, T _Zero:

$\left\{\begin{array}{c}{T}_a=\frac{({\mathrm{\&Delta;Q}}_b-{\mathrm{\&Delta;Q}}_{\mathrm{zero}})\&times;P_{\mathrm{error}}+({\mathrm{\&Delta;P}}_{\mathrm{zero}}-{\mathrm{\&Delta;P}}_b)\&times;Q_{\mathrm{error}}+({\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_{\mathrm{zero}})\&times;T_s}{{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_b+{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_{\mathrm{zero}}+{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_a-{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;Q}}_b-{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_{\mathrm{zero}}-{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_a}\\ T_b=\frac{({\mathrm{\&Delta;Q}}_{\mathrm{zero}}-{\mathrm{\&Delta;Q}}_b)\&times;P_{\mathrm{error}}+({\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;P}}_{\mathrm{zero}})\&times;Q_{\mathrm{error}}+(-{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_a+{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_{\mathrm{zero}})\&times;T_s}{{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_b+{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_{\mathrm{zero}}+{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_a-{\mathrm{\&Delta;Q}}_a{\mathrm{\&Delta;P}}_b-{\mathrm{\&Delta;Q}}_b{\mathrm{\&Delta;P}}_{\mathrm{zero}}-{\mathrm{\&Delta;Q}}_{\mathrm{zero}}{\mathrm{\&Delta;P}}_a}\\ T_{\mathrm{zero}}=T_s-T_a-T_b\end{array}\right.$

According to above formula, calculate when T occurring _b<0 o'clock, query optimization P-DPC switch list reselects voltage vector and calculates action time again, with accuracy and the validity that guarantees selected voltage vector and action time, and reduce because of not to occurring that vector effectively processes for negative situation the low order current harmonics caused action time.

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