CN102427236A - Method for suppressing total output reactive power fluctuation by adopting doubly-fed induction wind power system with series grid-side converter under unbalanced voltage - Google Patents

Abstract

The invention discloses a method for suppressing total output reactive power fluctuation by adopting a doubly-fed induction wind power system with series grid-side converters under unbalanced voltage. The method relates to the control of series and parallel grid-side converters and motor-side converters. Pulse-width modulation (PWM) driving signals of the series and parallel grid-side converters are generated through a specific method to control the series and parallel grid-side converters. Under unbalanced grid voltage, a doubly-fed induction generator (DFIG) with the series grid-side converters does not change the control strategies of a rotor-side converter. On the premise that the doubled frequency fluctuation of the output power of the generator does not occur, the doubled frequency fluctuation of the electromagnetic torque does not occur and the three-phase current of a stator and a rotor are in balance, through the coordination control of the series grid-side converters and the parallel grid-side converters, the goal that the doubled frequency fluctuation of the total output reactive power of the entire system does not occur is realized, and the quality of reactive power provided by the DFIG wind power system to the grid under unbalanced grid voltage is improved.

Description

Adopt the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation under the unbalance voltage

Technical field

The present invention relates to adopt the double-fed induction wind generator system technological improvement of series connection grid side converter; Particularly relate to the control method that the double-fed induction wind generator system that adopts the series connection grid side converter under the unbalance voltage suppresses the fluctuation of total output reactive power, belong to the power control technology field.

Background technology

Double fed induction generators (doubly fed induction generator; DFIG) stator directly links to each other with electrical network; If do not take the appropriate control measure; Uneven stator and the rotor current of just will making of then very little stator voltage occurs than large unbalance, causes the electromagnetic torque of generator and the power generation of being incorporated into the power networks is fluctuated widely, and motor stator and rotor winding is in the asymmetric operation state for a long time and also will brings problems such as unbalanced heating and winding insulation.And cause under the unbalanced source voltage that DFIG stator and rotor electric current is asymmetric, the basic reason of power output and electromagnetic torque fluctuation is the existence of motor stator negative sequence voltage; If can eliminate the negative sequence voltage component of DFIG stator; Then be expected to fundamentally solve the influence of unbalanced source voltage, realize the stable operation of DFIG under the unbalance voltage the DFIG operation.On the other hand; Along with being the increase of master's wind-electricity integration capacity with the double-fed induction wind generator system; New operation of power networks guide rule has also clearly proposed the reactive power operation requirement of being incorporated into the power networks to big capacity wind power system, promptly requires big capacity wind power system to provide stable reactive power support to satisfy the line voltage requirement to electrical network in some electric network faults operation occasion.At present, to the operation action of DFIG system under the unbalanced source voltage and the more existing solutions of control strategy, like disclosed following document:

(1) Hu Jiabing, He Yikang, Wang Hongsheng, etc., the Collaborative Control of double fed induction generators net side and rotor-side converter under the unbalanced electric grid voltage.Proceedings of the CSEE, 2010,30 (9): 97-104.

(2) Liao Yong, Li Hui, Yao Jun, etc., the double-fed fan motor unit low-voltage transition control strategy of employing series connection grid side converter.Proceedings of the CSEE, 2009,29 (27): 90-98.

(3) Li Hui, Liao Yong, Yao Jun, etc., under the unbalanced electric grid voltage based on the series connection grid side converter the DFIG control strategy.Automation of Electric Systems, 2010,34 (3): 96-100,106.

Document (1) is through coordinating control rotor-side converter (rotor-side converter; RSC) and parallelly connected grid side converter (parallel grid-side converter; PGSC) realize under the unbalance voltage or the ripple disable of whole system active power of output or output reactive power ripple disable or output current balance, the DFIG system performance provides useful treatment measures under the uneven condition in order to improve.Yet such scheme is owing to receive the restriction of DFIG system control variables, and it can't realize operational objectives such as motor stator and rotor current balance type, power output and electromagnetic torque ripple disable simultaneously, makes that the enhancing serviceability of DFIG is restricted under the unbalance voltage.

Document (2) has been furtherd investigate the low-voltage of this system and has been passed through progress control method, realizes that (series grid-side converter, DFIG system zero voltage failure SGSC) passes through operation based on the series connection grid side converter.And can also establish good basis through control SGSC injects series voltage in the generator unit stator loop characteristic in this system for the operation control problem of DFIG system under the solution unbalance voltage.

The control that document (3) proposes does not change the control strategy of RSC under the unbalance voltage; Realizing that DFIG stator and rotor three-phase current symmetry, power of motor and electromagnetic torque do not have on the basis of two frequencys multiplication fluctuation; Realized that successfully the total active power of output of DFIG system DC bus-bar voltage and system does not have the fluctuation of two frequencys multiplication, controlling for the operation of this system under the unbalanced source voltage provides new solution.But the document mainly is to suppress the controlling schemes of total active power of output two frequencys multiplication fluctuation to the DFIG system that adopts SGSC, and the idle control of total output does not propose feasible program to this system under the unbalanced source voltage as yet.

Summary of the invention

Above-mentioned deficiency to the prior art existence; The objective of the invention is to propose to adopt under a kind of unbalanced source voltage the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation, make system always export the reactive power degree of fluctuation and reduce greatly.

Technical scheme of the present invention is achieved in that

Adopt the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation under the unbalance voltage; This method relates to control, the control of parallelly connected grid side converter and the control of motor side converter to the series connection grid side converter; It is characterized in that the controlled step of said series connection grid side converter is:

A1) gather electrical network three-phase voltage signal u _Ga, u _Gb, u _Gc

A2) gather double fed induction generators stator three-phase voltage signal u _Sa, u _Sb, u _Sc

A3) with the electrical network three-phase voltage signal u that gathers _Ga, u _Gb, u _GcBe tied to the permanent Power Conversion of the static two phase α β systems of axis through static three-phase abc coordinate and obtain the voltage e under the α β axle system _α, e _βWherein, static three-phase abc coordinate is tied to the permanent Power Conversion formula of the static two phase α β systems of axis and is:

$\left[\begin{array}{c}{e}_{\mathrm{\α}}\\ e_{\mathrm{\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]$

Adopt the line voltage orientation to obtain line voltage e _GdWith electrical network electrical degree θ _g, its calculating formula is:

$e_{\mathrm{gd}}=\sqrt{e_{\mathrm{\α}}^2+e_{\mathrm{\β}}^2},$ ${\mathrm{\θ}}_g=\mathrm{arc}\tan \frac{e_{\mathrm{\β}}}{e_{\mathrm{\α}}}$

A4) e that steps A 3 is obtained _α, e _βAfter the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining line voltage dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{gd}+}^{+}\\ u_{\mathrm{gq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\θ}}_g\right)& \sin \left({\mathrm{\θ}}_g\right)\\ -\sin \left({\mathrm{\θ}}_g\right)& \cos \left({\mathrm{\θ}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{\α}}\\ e_{\mathrm{\β}}\end{array}\right]$

A5) e that steps A 3 is obtained _α, e _βThrough the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining line voltage dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{gd}-}^{-}\\ u_{\mathrm{gq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\θ}}_g\right)& \sin (-{\mathrm{\θ}}_g)\\ -\sin \left({-\mathrm{\θ}}_g\right)& \cos \left({-\mathrm{\θ}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{\α}}\\ e_{\mathrm{\β}}\end{array}\right]$

A6) with the double fed induction generators stator three-phase voltage signal u that gathers _Sa, u _Sb, u _ScBe tied to the permanent Power Conversion of the static two phase α β systems of axis through static three-phase abc coordinate and obtain the voltage e under the α β axle system _{S α}, e _{S β}Wherein, static three-phase abc coordinate system transformation to the permanent Power Conversion formula of the static two phase α β systems of axis is:

$\left[\begin{array}{c}{e}_{\mathrm{s\α}}\\ e_{\mathrm{s\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{sa}}\\ u_{\mathrm{sb}}\\ u_{\mathrm{sc}}\end{array}\right]$

A7) e that steps A 6 is obtained _{S α}, e _{S β}After the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining line voltage dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{sd}+}^{+}\\ u_{\mathrm{sq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\θ}}_g\right)& \sin \left({\mathrm{\θ}}_g\right)\\ -\sin \left({\mathrm{\θ}}_g\right)& \cos \left({\mathrm{\θ}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{s\α}}\\ e_{\mathrm{s\β}}\end{array}\right]$

A8) e that steps A 6 is obtained _{S α}, e _{S β}Through the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining line voltage dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{sd}-}^{-}\\ u_{\mathrm{sq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\θ}}_g\right)& \sin (-{\mathrm{\θ}}_g)\\ -\sin \left({-\mathrm{\θ}}_g\right)& \cos \left({-\mathrm{\θ}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{s\α}}\\ e_{\mathrm{s\β}}\end{array}\right]$

A9) under the unbalanced source voltage situation, the series connection grid side converter is realized stator voltage compensation control through taking voltage close loop to control, and the positive-negative sequence voltage control equation of series connection grid side converter is respectively as follows under two synchronous angular velocity rotating coordinate systems:

$\left\{\begin{array}{c}{u}_{\mathrm{seriesd}+}^{+}=(K_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">p</figure-callout>}1}+K_{i1}/s)(u_{\mathrm{gd}+}^{+}-u_{\mathrm{sd}+}^{+})\\ u_{\mathrm{seriesq}+}^{+}=(K_{\mathrm{<figure-callout\; id="1"\; label="p"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">p</figure-callout>}1}+K_{i1}/s)(u_{\mathrm{gq}+}^{+}-u_{\mathrm{sq}+}^{+})\\ u_{\mathrm{seriesd}-}^{-}=(K_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">p</figure-callout>}2}+K_{i2}/s)(0-u_{\mathrm{sd}-}^{-})\\ u_{\mathrm{seriesq}-}^{-}=(K_{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">p</figure-callout>}2}+K_{i2}/s)(0-u_{\mathrm{sq}-}^{-})\end{array}\right.$

Wherein, K _P1And K _I1Be respectively the proportionality coefficient and the integral coefficient of positive sequence voltage pi regulator, K _P2And K _I2Be respectively the proportionality coefficient and the integral coefficient of negative sequence voltage pi regulator, K _P1＜0, K _P2＜0.

A10) obtained in step A9 string positive sequence network side converter control voltage The angular velocity of the rotating coordinate system forward synchronization to the stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinates shafting positive sequence under the control voltage

Where: forward synchronization angular velocity rotating coordinate system to a stationary two-phase αβ coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{series\&alpha;}+}^{+}\\ u_{\mathrm{series\&beta;}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& -\sin \left({\mathrm{\&theta;}}_g\right)\\ \sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{seriesd}+}^{+}\\ u_{\mathrm{seriesq}+}^{+}\end{array}\right]$

A11) obtained in step A9 string negative sequence network side converter control voltage

The angular velocity of the rotating coordinate system reverse synchronization to a stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinates shafting negative sequence under the control voltage

Of which: reverse synchronization angular velocity rotating coordinate system to a standstill two-phase αβ coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{series\&alpha;}-}^{-}\\ u_{\mathrm{series\&beta;}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& -\sin (-{\mathrm{\&theta;}}_g)\\ \sin \left({-\mathrm{\&theta;}}_g\right)& \cos (-{\mathrm{\&theta;}}_g)\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{seriesd}-}^{-}\\ u_{\mathrm{seriesq}-}^{-}\end{array}\right]$

A12) with steps A 10 and the resulting series connection grid side converter of A11 positive-negative sequence control voltage

With dc voltage U _DcProduce series connection grid side converter PWM drive signal through space vector modulation.

The controlled step of said parallelly connected grid side converter is:

B1) gather double fed induction generators stator three-phase current signal i _Sa, i _Sb, i _Sc

B2) the three-phase current signal i of the parallelly connected grid side converter of collection _Ga, i _Gb, i _Gc

B3) gather direct current chain voltage signal U _Dc

The parallelly connected grid side converter three-phase current signal i that B4) will collect _Ga, i _Gb, i _GcPermanent Power Conversion obtains the current i under the α β axle system to the static two phase α β systems of axis through static abc three phase coordinate systems _{G α}, i _{G β}Wherein, static abc three phase coordinate systems to the permanent Power Conversion formula of the static two phase α β systems of axis are:

$\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]$

B5) i that step B4 is obtained _{G α}, i _{G β}After the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{gd}+}^{+}\\ i_{\mathrm{gq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]$

B6) i that step B4 is obtained _{G α}, i _{G β}Through the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{gd}-}^{-}\\ i_{\mathrm{gq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]$

B70 is with the stator three-phase current signal i that collects _Sa, i _Sb, i _ScPermanent Power Conversion obtains the current i under the α β axle system to the static two phase α β systems of axis through static abc three phase coordinate systems _{S α}, i _{S β}Wherein, static abc three phase coordinate systems to the permanent Power Conversion formula of the static two phase α β systems of axis are:

$\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{sa}}\\ i_{\mathrm{sb}}\\ i_{\mathrm{sc}}\end{array}\right]$

B8) i that step B7 is obtained _{S α}, i _{S β}After the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{sd}+}^{+}\\ i_{\mathrm{sq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]$

B9) i that step B7 is obtained _{S α}, i _{S β}Through the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{sd}-}^{-}\\ i_{\mathrm{sq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]$

B10) DC bus-bar voltage of parallelly connected grid side converter is regulated and is adopted pi regulator control; Its adjuster output and DC bus-bar voltage set-point

constitute DC bus-bar voltage average active power set-point, that is:

$P_{g\_\mathrm{av}}^{*}=(K_{\mathrm{pu}}+K_{\mathrm{iu}}/s)(U_{\mathrm{dc}}^{*}-U_{\mathrm{dc}})\&CenterDot;U_{\mathrm{dc}}^{*}$

Wherein:

Represent that parallelly connected grid side converter keeps DC bus-bar voltage and stablize the instruction of required average active power,

Be DC bus-bar voltage set-point, K _PuAnd K _IuBe respectively DC bus-bar voltage adjuster proportionality coefficient and integral coefficient;

B11) parallelly connected grid side converter adopts the positive sequence line voltage to be oriented to the d axle; Then

at this moment, system's positive and negative preface electric current set-point that the inhibition system always exports reactive power pulsation is:

$\left[\begin{array}{c}{i}_{\mathrm{gd}+}^{+*}\\ i_{\mathrm{gq}+}^{+*}\\ i_{\mathrm{gd}-}^{-*}\\ i_{\mathrm{gq}-}^{-*}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{gd}+}^{+}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}-\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}\\ -\frac{u_{\mathrm{gd}+}^{+}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\\ -\frac{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_1\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}-\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\\ \frac{k_3\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{k_1\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\end{array}\right]$

Wherein:

$u_{g+}^{+}=u_{\mathrm{gd}+}^{+}$

${\left(u_{g-}^{-}\right)}^2={\left(u_{\mathrm{gd}-}^{-}\right)}^2+{\left(u_{\mathrm{gq}-}^{-}\right)}^2$

$Q_{g\_\mathrm{av}}^{*}=0$

$Q_{\mathrm{series}\_\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">cos</figure-callout>}2}=-u_{\mathrm{gq}-}^{-}\&CenterDot;i_{\mathrm{sd}+}^{+}+u_{\mathrm{gd}-}^{-}\&CenterDot;i_{\mathrm{sq}+}^{+}$

$Q_{\mathrm{series}\_\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">sin</figure-callout>}2}=u_{\mathrm{gd}-}^{-}\&CenterDot;i_{\mathrm{sd}+}^{+}+u_{\mathrm{gq}-}^{-}\&CenterDot;i_{\mathrm{sq}+}^{+}$

${\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_1=-{2u}_{\mathrm{gd}+}^{+}\&CenterDot;u_{\mathrm{gd}-}^{-}\&CenterDot;u_{\mathrm{gq}-}^{-}$

${\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">k</figure-callout>}}_2={\left(u_{\mathrm{gd}+}^{+}\right)}^3-u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gd}-}^{-}\right)}^2+u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gq}-}^{-}\right)}^2$

$k_3=-({\left(u_{\mathrm{gd}+}^{+}\right)}^3-{u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gq}-}^{-}\right)}^2+u}_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gd}-}^{-}\right)}^2)$

B12) under unbalanced electric grid voltage; Parallelly connected grid side converter is adopted the current on line side control under pair synchronization rotational coordinate axs system; Adopt electrical network positive sequence voltage oriented approach, the positive-negative sequence control voltage equation of parallelly connected grid side converter in two synchronization rotational coordinate axs are is under the unbalanced electric grid voltage:

$\left\{\begin{array}{c}{u}_{d+}^{+}=-({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="2"\; label="K\; i"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(i_{\mathrm{gd}+}^{+*}-i_{\mathrm{gd}+}^{+})+{\mathrm{\&omega;L}}_g{i}_{\mathrm{gq}+}^{+}+u_{\mathrm{gd}+}^{+}\\ u_{q+}^{+}=-({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="2"\; label="K\; i"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(i_{\mathrm{gq}+}^{+*}-i_{\mathrm{gq}+}^{+})-{\mathrm{\&omega;L}}_g{i}_{\mathrm{gd}+}^{+}\\ u_{d-}^{-}=-(K_{p2-}+K_{i2-}/s)(i_{\mathrm{gd}-}^{-*}-i_{\mathrm{gd}-}^{-})-{\mathrm{\&omega;L}}_g{i}_{\mathrm{gq}-}^{-}+u_{\mathrm{gd}-}^{-}\\ u_{q-}^{-}=-(K_{p2-}+K_{i2-}/s)(i_{\mathrm{gq}-}^{-*}-i_{\mathrm{gq}-}^{-})+{\mathrm{\&omega;L}}_g{i}_{\mathrm{gd}-}^{-}+u_{\mathrm{gq}-}^{-}\end{array}\right.$

Wherein: K _P2+And K _I2+Be respectively the proportionality coefficient and the integral coefficient of positive sequence voltage pi regulator, K _P2-And K _I2-Be respectively the proportionality coefficient and the integral coefficient of negative sequence voltage pi regulator, ω is synchronous electric angle speed, L _gBe parallelly connected grid side converter inlet wire reactor inductance;

B13) obtained in step B12 positive sequence control voltage

The angular velocity of the rotating coordinate system forward synchronization to the stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinates shafting positive sequence under the control voltage where: forward synchronization angular velocity of the rotating coordinate system to a stationary two-phase αβ coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{\&alpha;}+}^{+}\\ u_{\mathrm{\&beta;}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& -\sin \left({\mathrm{\&theta;}}_g\right)\\ \sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{d+}^{+}\\ u_{q+}^{+}\end{array}\right]$

B14) obtained in step B12 negative sequence control voltage

the angular velocity of the rotating coordinate system reverse synchronization to a stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinates shafting negative sequence under the control voltage

where: reverse synchronization angular velocity of the rotating coordinate system to a stationary two-phase αβ coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{\&alpha;}-}^{-}\\ u_{\mathrm{\&beta;}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& -\sin \left({-\mathrm{\&theta;}}_g\right)\\ \sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{d-}^{-}\\ u_{q-}^{-}\end{array}\right]$

B15) with step B13, the resulting positive-negative sequence control of B14 voltage With dc voltage U _DcProduce parallelly connected grid side converter PWM drive signal through space vector modulation.

The invention has the beneficial effects as follows:

Realized that under unbalanced source voltage dual feedback wind power generation system stator and rotor three-phase current symmetry, power of motor and the electromagnetic torque of employing series connection grid side converter do not have the controlled target of two frequencys multiplication fluctuation, whole system can provide to electrical network and stablize pulsation-free reactive power support simultaneously.When adopting traditional control method, system always exports reactive power and has two frequencys multiplication fluctuation largely, and after adopting the method for the invention, system always exports the reactive power degree of fluctuation and reduces greatly.

Description of drawings

Fig. 1 is a theory diagram of the present invention.

Fig. 2 is series connection grid side converter positive-negative sequence voltage control block diagram.

Fig. 3 is a direct current chain voltage control block diagram.

Fig. 4 adopts the system emulation oscillogram of traditional control method down for unbalanced source voltage.

Fig. 5 adopts the system emulation oscillogram of control method of the present invention down for unbalanced source voltage.

Be respectively double fed induction generators stator three-phase current (a) among Fig. 4 and Fig. 5; Series transformer voltage (b); System always exports reactive power (c); Direct current chain voltage (d); Given and the feedback (e) of parallel connection grid side converter negative-sequence current q axle component; Given and the feedback (f) of parallel connection grid side converter negative-sequence current d axle component; Whole system total current (g); Double fed induction generators electromagnetic torque (h); Double fed induction generators rotor three-phase electric current (i); Generator output; Output of parallel connection grid side converter and the total active power of output of system (j); Parallel connection grid side converter output reactive power (k); Parallel connection grid side converter forward-order current d; Given and the feedback (l) of q axle component; Electrical network and stator positive sequence voltage d axle component (m); Electrical network and stator positive sequence voltage q axle component (n); Generator output reactive power (o); Electrical network and stator negative sequence voltage d axle component (p); Electrical network and stator negative sequence voltage q axle component (q).

Embodiment

Below in conjunction with accompanying drawing specific embodiments of the present invention is described in detail.

As shown in Figure 1, adopt the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation under a kind of unbalance voltage of the present invention, the controlling object that it comprises has: direct current chain electric capacity 1; Motor side converter 2, parallelly connected grid side converter 3, space vector pulse width modulation module 4; Double-fed induction wind driven generator 5, series connection grid side converter 6, step-up transformer 7; Current Hall transducer 8, voltage hall sensor 9, parallelly connected grid side converter current-order set-point computing module 10; Positive sequence voltage control module 11; Negative sequence voltage control module 12, trapper 13, forward synchronous angular velocity rotational coordinates are tied to the permanent Power Conversion 14 of the static two phase α β systems of axis; Reverse sync angular speed rotational coordinates is tied to the permanent Power Conversion 15 of the static two phase α β systems of axis; Static abc three phase coordinate systems are to the permanent Power Conversion 16 of the static two phase α β systems of axis, and the static two phase α β systems of axis are to the permanent Power Conversion 17 of forward synchronous angular velocity rotating coordinate system, and the static two phase α β systems of axis are to the permanent Power Conversion 18 of reverse sync angular speed rotating coordinate system.

Adopt the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation under the unbalance voltage of the present invention, its practical implementation step is following:

(A) series connection grid side converter controlled step:

A1) at first utilize voltage hall sensor 9 to gather electrical network three-phase voltage signal u _Ga, u _Gb, u _Gc

A2) utilize voltage hall sensor 9 to gather double fed induction generators stator three-phase voltage signal u _Sa, u _Sb, u _Sc

A3) utilize the three phase network voltage signal u that gathers _Ga, u _Gb, u _GcBe tied to the permanent Power Conversion module 16 of the static two phase α β systems of axis through static three-phase abc coordinate and obtain the voltage e under the static two phase α β axles system _α, e _βWherein, static three-phase abc coordinate system transformation to the permanent Power Conversion module 16 of the static two phase α β systems of axis is:

$\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]$

Adopt the line voltage orientation to obtain line voltage e _GdWith electrical network electrical degree θ _g, its calculating formula is:

$e_{\mathrm{gd}}=\sqrt{e_{\mathrm{\&alpha;}}^2+e_{\mathrm{\&beta;}}^2},$ ${\mathrm{\&theta;}}_g=\mathrm{arc}\tan \frac{e_{\mathrm{\&beta;}}}{e_{\mathrm{\&alpha;}}}$

A4) e that steps A 3 is obtained _α, e _βAfter the static two phase α β systems of axis arrive the permanent Power Conversion module 17 of forward synchronous angular velocity rotating coordinate system, again through obtaining line voltage dq axle component under the forward synchronous rotating frame after 13 filtering of 2 ω trappers

With

Wherein: the static two phase α β systems of axis to the permanent Power Conversion module 17 of forward synchronous angular velocity rotating coordinate system are:

$\left[\begin{array}{c}{u}_{\mathrm{gd}+}^{+}\\ u_{\mathrm{gq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

A5) e that steps A 3 is obtained _α, e _βThrough the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system after the permanent Power Conversion module 18, again through obtaining line voltage dq axle component under the reverse sync rotating coordinate system after 13 filtering of 2 ω trappers

With

Wherein: the static two phase α β systems of axis to the permanent Power Conversion module 18 of reverse sync angular speed rotating coordinate system are:

$\left[\begin{array}{c}{u}_{\mathrm{gd}-}^{-}\\ u_{\mathrm{gq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

A6) utilize the double fed induction generators stator three-phase voltage signal u that gathers _Sa, u _Sb, u _ScBe tied to the permanent Power Conversion module 16 of the static two phase α β systems of axis through static three-phase abc coordinate and obtain the voltage e under the α β axle system _{S α}, e _{S β}, wherein, static three-phase abc coordinate system transformation to the permanent Power Conversion module 16 of the static two phase α β systems of axis is:

$\left[\begin{array}{c}{e}_{\mathrm{s\&alpha;}}\\ e_{\mathrm{s\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{sa}}\\ u_{\mathrm{sb}}\\ u_{\mathrm{sc}}\end{array}\right]$

A7) e that steps A 6 is obtained _{S α}, e _{S β}After the static two phase α β systems of axis arrive the conversion module 17 of forward synchronous angular velocity rotating coordinate system, again through obtaining line voltage dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system conversion module 17 are:

$\left[\begin{array}{c}{u}_{\mathrm{sd}+}^{+}\\ u_{\mathrm{sq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{s\&alpha;}}\\ e_{\mathrm{s\&beta;}}\end{array}\right]$

A8) e that steps A 6 is obtained _{S α}, e _{S β}Through the static two phase α β systems of axis behind reverse sync angular speed rotating coordinate system conversion module 18, again through obtaining line voltage dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system conversion module 18 are:

$\left[\begin{array}{c}{u}_{\mathrm{sd}-}^{-}\\ u_{\mathrm{sq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{s\&alpha;}}\\ e_{\mathrm{s\&beta;}}\end{array}\right]$

A9) under the unbalanced source voltage situation, realize stator voltage compensation control through taking voltage close loop to control, referring to Fig. 2, the positive and negative sequence voltage governing equation of SGSC is respectively as follows under two synchronous rotary axis:

$\left\{\begin{array}{c}{u}_{\mathrm{seriesd}+}^{+}=({\mathrm{<figure-callout\; id="1"\; label="K\; p"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="1"\; label="K\; i"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(u_{\mathrm{gd}+}^{+}-u_{\mathrm{sd}+}^{+})\\ u_{\mathrm{seriesq}+}^{+}=({\mathrm{<figure-callout\; id="1"\; label="K\; p"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="1"\; label="K\; i"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(u_{\mathrm{gq}+}^{+}-u_{\mathrm{sq}+}^{+})\\ u_{\mathrm{seriesd}-}^{-}=({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="2"\; label="K\; i"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(0-u_{\mathrm{sd}-}^{-})\\ u_{\mathrm{seriesq}-}^{-}=({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="2"\; label="K\; i"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(0-u_{\mathrm{sq}-}^{-})\end{array}\right.$

K in the formula _P1And K _I1Be respectively the proportionality coefficient and the integral coefficient of positive sequence voltage pi regulator, K _P2And K _I2Be respectively the proportionality coefficient and the integral coefficient of negative sequence voltage pi regulator, K _P1＜0, K _P2＜0.

A10) obtained in step A9 string positive sequence network side converter control voltage

The angular velocity of the rotating coordinate system forward synchronization to the stationary two-phase αβ coordinate shafting constant power conversion module 14 to get to the stationary shaft under the two-phase αβ coordinates are sequence control voltage

where: Forward synchronous rotating coordinate system to the angular velocity of the two-phase αβ stationary coordinate shafting constant power conversion module 14 is:

$\left[\begin{array}{c}{u}_{\mathrm{series\&alpha;}+}^{+}\\ u_{\mathrm{series\&beta;}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& -\sin \left({\mathrm{\&theta;}}_g\right)\\ \sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{seriesd}+}^{+}\\ u_{\mathrm{seriesq}+}^{+}\end{array}\right]$

A11) obtained in step A9 string negative sequence network side converter control voltage

The angular velocity of the rotating coordinate system reverse synchronization to a stationary two-phase αβ coordinate shafting constant power conversion module 15 to get to the two-phase αβ stationary Axis systems under negative sequence control voltage

where: reverse synchronization angular velocity rotating coordinate system to a stationary two-phase αβ coordinate shafting constant power conversion module 15 is:

$\left[\begin{array}{c}{u}_{\mathrm{series\&alpha;}-}^{-}\\ u_{\mathrm{series\&beta;}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& -\sin (-{\mathrm{\&theta;}}_g)\\ \sin \left({-\mathrm{\&theta;}}_g\right)& \cos (-{\mathrm{\&theta;}}_g)\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{seriesd}-}^{-}\\ u_{\mathrm{seriesq}-}^{-}\end{array}\right]$

A12) with steps A 10, the resulting series connection grid side converter of A11 positive-negative sequence control voltage

With dc voltage U _DcProduce series connection grid side converter PWM drive signal through space vector modulation (SVPWM) module 4.

(B) parallelly connected grid side converter controlled step:

B1) at first utilize current Hall transducer 8 to gather double fed induction generators stator three-phase current signal i _Sa, i _Sb, i _Sc

B2) utilize current Hall transducer 8 to gather the three-phase current signal i of parallelly connected grid side converter _Ga, i _Gb, i _Gc

B3) utilize voltage hall sensor 9 to gather dc voltage signal U _Dc

The parallelly connected grid side converter three-phase current signal i that B4) will collect _Ga, i _Gb, i _GcPermanent Power Conversion module 16 obtains the current i under the α β axle system to the static two phase α β systems of axis through static abc three phase coordinate systems _{G α}, i _{G β}Wherein, static abc three phase coordinate systems to the permanent Power Conversion module 16 of the static two phase α β systems of axis are:

$\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]$

B5) i that step B4 is obtained _{G α}, i _{G β}After the static two phase α β systems of axis arrive the conversion module 17 of forward synchronous angular velocity rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system conversion module 17 are:

$\left[\begin{array}{c}{i}_{\mathrm{gd}+}^{+}\\ i_{\mathrm{gq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]$

B6) i that step B4 is obtained _{G α}, i _{G β}Through the static two phase α β systems of axis behind the conversion module 18 of reverse sync angular speed rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system conversion module 18 are:

$\left[\begin{array}{c}{i}_{\mathrm{gd}-}^{-}\\ i_{\mathrm{gq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]$

B7) with the stator three-phase current signal i that collects _Sa, i _Sb, i _ScPermanent Power Conversion module 16 obtains the current i under the static two phase α β axles system to the static two phase α β systems of axis through static abc three phase coordinate systems _{S α}, i _{S β}Wherein, static abc three phase coordinate systems to the permanent Power Conversion module 16 of the static two phase α β systems of axis are:

$\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{sa}}\\ i_{\mathrm{sb}}\\ i_{\mathrm{sc}}\end{array}\right]$

B8) i that step B7 is obtained _{S α}, i _{S β}After the static two phase α β systems of axis arrive forward synchronous angular velocity rotating coordinate system conversion module 17, again through obtaining generator unit stator electric current dq axle component under the forward synchronous rotating frame after 13 filtering of 2 ω trappers

With Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system conversion module 17 are:

$\left[\begin{array}{c}{i}_{\mathrm{sd}+}^{+}\\ i_{\mathrm{sq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]$

B9) i that step B7 is obtained _{S α}, i _{S β}Through the static two phase α β systems of axis behind reverse sync angular speed rotating coordinate system conversion module 18, again through obtaining generator unit stator electric current dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis are that module 18 is to reverse sync angular speed rotating coordinate transformation:

$\left[\begin{array}{c}{i}_{\mathrm{sd}-}^{-}\\ i_{\mathrm{sq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]$

B10) DC bus-bar voltage of parallelly connected grid side converter is regulated and is adopted conventional pi regulator control; Its adjuster output and DC bus-bar voltage set-point

constitute DC bus-bar voltage average active power set-point; Referring to Fig. 3, that is:

$P_{g\_\mathrm{av}}^{*}=(K_{\mathrm{pu}}+K_{\mathrm{iu}}/s)(U_{\mathrm{dc}}^{*}-U_{\mathrm{dc}})\&CenterDot;U_{\mathrm{dc}}^{*}$

Wherein:

Represent that parallelly connected grid side converter keeps DC bus-bar voltage and stablize the instruction of required average active power, Be DC bus-bar voltage set-point, K _PuAnd K _IuBe respectively DC bus-bar voltage adjuster proportionality coefficient and integral coefficient;

B11) adopt the positive sequence line voltage to be oriented to the d axle, then

obtains the positive-negative sequence current set-point by parallelly connected grid side converter current-order set-point computing module 10.Wherein, parallelly connected grid side converter current-order set-point computing module 10 is:

$\left[\begin{array}{c}{i}_{\mathrm{gd}+}^{+*}\\ i_{\mathrm{gq}+}^{+*}\\ i_{\mathrm{gd}-}^{-*}\\ i_{\mathrm{gq}-}^{-*}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{gd}+}^{+}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}-\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}\\ -\frac{u_{\mathrm{gd}+}^{+}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\\ -\frac{k_1\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{k_2\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}-\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\\ \frac{k_3\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{k_1\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\end{array}\right]$

Wherein:

$u_{g+}^{+}=u_{\mathrm{gd}+}^{+}$

${\left(u_{g-}^{-}\right)}^2={\left(u_{\mathrm{gd}-}^{-}\right)}^2+{\left(u_{\mathrm{gq}-}^{-}\right)}^2$

$Q_{g\_\mathrm{av}}^{*}=0$

$Q_{\mathrm{series}\_\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">cos</figure-callout>}2}=-u_{\mathrm{gq}-}^{-}\&CenterDot;i_{\mathrm{sd}+}^{+}+u_{\mathrm{gd}-}^{-}\&CenterDot;i_{\mathrm{sq}+}^{+}$

$Q_{\mathrm{series}\_\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">sin</figure-callout>}2}=u_{\mathrm{gd}-}^{-}\&CenterDot;i_{\mathrm{sd}+}^{+}+u_{\mathrm{gq}-}^{-}\&CenterDot;i_{\mathrm{sq}+}^{+}$

${\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="HDA0000122184470000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_1=-{2u}_{\mathrm{gd}+}^{+}\&CenterDot;u_{\mathrm{gd}-}^{-}\&CenterDot;u_{\mathrm{gq}-}^{-}$

${\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">k</figure-callout>}}_2={\left(u_{\mathrm{gd}+}^{+}\right)}^3-u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gd}-}^{-}\right)}^2+u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gq}-}^{-}\right)}^2$

$k_3=-({\left(u_{\mathrm{gd}+}^{+}\right)}^3-{u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gq}-}^{-}\right)}^2+u}_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gd}-}^{-}\right)}^2)$

B12) under unbalanced electric grid voltage, adopt electrical network positive sequence voltage oriented approach, parallelly connected grid side converter is adopted the current on line side control under pair synchronization rotational coordinate axs system, obtaining the forward synchronization rotational coordinate ax by positive sequence voltage control module 11 is dq control voltage; Obtaining the reverse sync rotatable coordinate axis by negative sequence voltage control module 12 is dq control voltage.Wherein, positive sequence voltage control module 11 with negative sequence voltage control module 12 is:

$\left\{\begin{array}{c}{u}_{d+}^{+}=-({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="2"\; label="K\; i"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(i_{\mathrm{gd}+}^{+*}-i_{\mathrm{gd}+}^{+})+{\mathrm{\&omega;L}}_g{i}_{\mathrm{gq}+}^{+}+u_{\mathrm{gd}+}^{+}\\ u_{q+}^{+}=-({\mathrm{<figure-callout\; id="2"\; label="K\; p"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_p+{\mathrm{<figure-callout\; id="2"\; label="K\; i"\; filenames="HDA0000122184470000011.png,HDA0000122184470000021.png"\; state="\{\{state\}\}">K</figure-callout>}}_i/s)(i_{\mathrm{gq}+}^{+*}-i_{\mathrm{gq}+}^{+})-{\mathrm{\&omega;L}}_g{i}_{\mathrm{gd}+}^{+}\\ u_{d-}^{-}=-(K_{p2-}+K_{i2-}/s)(i_{\mathrm{gd}-}^{-*}-i_{\mathrm{gd}-}^{-})-{\mathrm{\&omega;L}}_g{i}_{\mathrm{gq}-}^{-}+u_{\mathrm{gd}-}^{-}\\ u_{q-}^{-}=-(K_{p2-}+K_{i2-}/s)(i_{\mathrm{gq}-}^{-*}-i_{\mathrm{gq}-}^{-})+{\mathrm{\&omega;L}}_g{i}_{\mathrm{gd}-}^{-}+u_{\mathrm{gq}-}^{-}\end{array}\right.$

Wherein: K _P2+And K _I2+Be respectively the proportionality coefficient and the integral coefficient of positive sequence voltage pi regulator, K _P2-And K _I2-Be respectively the proportionality coefficient and the integral coefficient of negative sequence voltage pi regulator, ω is a synchronous angular velocity, L _gBe parallelly connected grid side converter inlet wire reactor inductance;

B13) obtained in step B12 positive sequence control voltage

The angular velocity of the rotating coordinate system forward synchronization to the stationary two-phase αβ coordinate shafting constant power conversion module 14 to obtain the two-phase αβ stationary Axis systems under positive sequence control voltage

where: Positive angular velocity of the rotating coordinate system to synchronize to a stationary two-phase αβ coordinate shafting constant power conversion module 14 is:

$\left[\begin{array}{c}{u}_{\mathrm{\&alpha;}+}^{+}\\ u_{\mathrm{\&beta;}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& -\sin \left({\mathrm{\&theta;}}_g\right)\\ \sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{d+}^{+}\\ u_{q+}^{+}\end{array}\right]$

B14) obtained in step B12 negative sequence control voltage

the angular velocity of the rotating coordinate system reverse synchronization to a stationary two-phase αβ coordinate shafting constant power conversion module 15 to obtain the two-phase αβ stationary Axis systems under negative sequence control voltage where: anti-angular velocity of the rotating coordinate system to synchronize to a stationary two-phase αβ coordinate shafting constant power conversion module 15 is:

$\left[\begin{array}{c}{u}_{\mathrm{\&alpha;}-}^{-}\\ u_{\mathrm{\&beta;}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& -\sin \left({-\mathrm{\&theta;}}_g\right)\\ \sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{d-}^{-}\\ u_{q-}^{-}\end{array}\right]$

B15) with step B13, the resulting positive-negative sequence control of B14 voltage With dc voltage U _DcProduce parallelly connected grid side converter PWM drive signal through space vector modulation (SVPWM) module 4.

(C) control strategy of motor side converter

(C1) motor side converter using conventional vector control strategy, its control voltage and dc voltage U _DcProduce motor side converter PWM drive signal through space vector modulation module 4.

The present invention has realized adopting dual feedback wind power generation system stator and rotor three-phase current symmetry, power of motor and the electromagnetic torque of series connection grid side converter not to have the controlled target that two frequencys multiplication fluctuate under unbalanced source voltage; Whole system can provide to electrical network and stablize pulsation-free reactive power support simultaneously, shown in accompanying drawing 5 (a), (i), (j), (h).Shown in contrast accompanying drawing 4 (c) and Fig. 5 (c); When adopting tradition control (accompanying drawing 4 (c)); System always exports reactive power and has two frequencys multiplication fluctuation largely, and after adopting this paper institute's inventive method (accompanying drawing 5 (c)), system always exports the reactive power degree of fluctuation and reduces greatly.

Be respectively double fed induction generators stator three-phase current (a) among Fig. 4 and Fig. 5; Series transformer voltage (b); System always exports reactive power (c); Direct current chain voltage (d); Given and the feedback (e) of parallel connection grid side converter negative-sequence current q axle component; Given and the feedback (f) of parallel connection grid side converter negative-sequence current d axle component; Whole system total current (g); Double fed induction generators electromagnetic torque (h); Double fed induction generators rotor three-phase electric current (i); Generator output; Output of parallel connection grid side converter and the total active power of output of system (j); Parallel connection grid side converter output reactive power (k); Parallel connection grid side converter forward-order current d; Given and the feedback (l) of q axle component; Electrical network and stator positive sequence voltage d axle component (m); Electrical network and stator positive sequence voltage q axle component (n); Generator output reactive power (o); Electrical network and stator negative sequence voltage d axle component (p); Electrical network and stator negative sequence voltage q axle component (q).

Claims (2)

1. adopt the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation under the unbalance voltage; This method relates to control, the control of parallelly connected grid side converter and the control of motor side converter to the series connection grid side converter; It is characterized in that the controlled step of said series connection grid side converter is:

A1) gather electrical network three-phase voltage signal u _Ga, u _Gb, u _Gc

A2) gather double fed induction generators stator three-phase voltage signal u _Sa, u _Sb, u _Sc

A3) with the electrical network three-phase voltage signal u that gathers _Ga, u _Gb, u _GcBe tied to the permanent Power Conversion of the static two phase α β systems of axis through static three-phase abc coordinate and obtain the voltage e under the α β axle system _α, e _βWherein, static three-phase abc coordinate is tied to the permanent Power Conversion formula of the static two phase α β systems of axis and is:

$\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]$

Adopt the line voltage orientation to obtain line voltage e _GdWith electrical network electrical degree θ _g, its calculating formula is:

$e_{\mathrm{gd}}=\sqrt{e_{\mathrm{\&alpha;}}^2+e_{\mathrm{\&beta;}}^2},$ ${\mathrm{\&theta;}}_g=\mathrm{arc}\tan \frac{e_{\mathrm{\&beta;}}}{e_{\mathrm{\&alpha;}}}$

A4) e that steps A 3 is obtained _α, e _βAfter the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining line voltage dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{gd}+}^{+}\\ u_{\mathrm{gq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

A5) e that steps A 3 is obtained _α, e _βThrough the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining line voltage dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{gd}-}^{-}\\ u_{\mathrm{gq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]$

A6) with the double fed induction generators stator three-phase voltage signal u that gathers _Sa, u _Sb, u _ScBe tied to the permanent Power Conversion of the static two phase α β systems of axis through static three-phase abc coordinate and obtain the voltage e under the α β axle system _{S α}, e _{S β}Wherein, static three-phase abc coordinate system transformation to the permanent Power Conversion formula of the static two phase α β systems of axis is:

$\left[\begin{array}{c}{e}_{\mathrm{s\&alpha;}}\\ e_{\mathrm{s\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{sa}}\\ u_{\mathrm{sb}}\\ u_{\mathrm{sc}}\end{array}\right]$

A7) e that steps A 6 is obtained _{S α}, e _{S β}After the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining line voltage dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering With Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{sd}+}^{+}\\ u_{\mathrm{sq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{s\&alpha;}}\\ e_{\mathrm{s\&beta;}}\end{array}\right]$

A8) e that steps A 6 is obtained _{S α}, e _{S β}Through the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining line voltage dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{u}_{\mathrm{sd}-}^{-}\\ u_{\mathrm{sq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{e}_{\mathrm{s\&alpha;}}\\ e_{\mathrm{s\&beta;}}\end{array}\right]$

A9) under the unbalanced source voltage situation, the series connection grid side converter is realized stator voltage compensation control through taking voltage close loop to control, and the positive-negative sequence voltage control equation of series connection grid side converter is respectively as follows under two synchronous angular velocity rotating coordinate systems:

$\left\{\begin{array}{c}{u}_{\mathrm{seriesd}+}^{+}=(K_{p1}+K_{i1}/s)(u_{\mathrm{gd}+}^{+}-u_{\mathrm{sd}+}^{+})\\ u_{\mathrm{seriesq}+}^{+}=(K_{p1}+K_{i1}/s)(u_{\mathrm{gq}+}^{+}-u_{\mathrm{sq}+}^{+})\\ u_{\mathrm{seriesd}-}^{-}=(K_{p2}+K_{i2}/s)(0-u_{\mathrm{sd}-}^{-})\\ u_{\mathrm{seriesq}-}^{-}=(K_{p2}+K_{i2}/s)(0-u_{\mathrm{sq}-}^{-})\end{array}\right.$

Wherein, K _P1And K _I1Be respectively the proportionality coefficient and the integral coefficient of positive sequence voltage pi regulator, K _P2And K _I2Be respectively the proportionality coefficient and the integral coefficient of negative sequence voltage pi regulator, K _P1＜0, K _P2＜0;

A10) obtained in step A9 string positive sequence network-side converter control voltage

The angular velocity of the rotating coordinate system forward synchronization to the stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinate shafting positive sequence under the control voltage

where: Forward synchronous rotating coordinate system to the angular velocity of the two-phase αβ stationary coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{series\&alpha;}+}^{+}\\ u_{\mathrm{series\&beta;}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& -\sin \left({\mathrm{\&theta;}}_g\right)\\ \sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{seriesd}+}^{+}\\ u_{\mathrm{seriesq}+}^{+}\end{array}\right]$

A11) obtained in step A9 string negative sequence network-side converter control voltage

The angular velocity of the rotating coordinate system reverse synchronization to a stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinate shafting negative sequence under the control voltage where: reverse synchronization angular velocity rotating coordinate system to a stationary two-phase αβ coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{series\&alpha;}-}^{-}\\ u_{\mathrm{series\&beta;}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& -\sin (-{\mathrm{\&theta;}}_g)\\ \sin \left({-\mathrm{\&theta;}}_g\right)& \cos (-{\mathrm{\&theta;}}_g)\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{seriesd}-}^{-}\\ u_{\mathrm{seriesq}-}^{-}\end{array}\right]$

A12) with steps A 10 and the resulting series connection grid side converter of A11 positive-negative sequence control voltage

With dc voltage U _DcProduce series connection grid side converter PWM drive signal through space vector modulation.

2. adopt the double-fed induction wind power system of series connection grid side converter to suppress total method of exporting the reactive power fluctuation under the unbalance voltage according to claim 1, it is characterized in that: the controlled step of said parallelly connected grid side converter is:

B1) gather double fed induction generators stator three-phase current signal i _Sa, i _Sb, i _Sc

B2) the three-phase current signal i of the parallelly connected grid side converter of collection _Ga, i _Gb, i _Gc

B3) gather direct current chain voltage signal U _Dc

The parallelly connected grid side converter three-phase current signal i that B4) will collect _Ga, i _Gb, i _GcPermanent Power Conversion obtains the current i under the α β axle system to the static two phase α β systems of axis through static abc three phase coordinate systems _{G α}, i _{G β}Wherein, static abc three phase coordinate systems to the permanent Power Conversion formula of the static two phase α β systems of axis are:

$\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]$

B5) i that step B4 is obtained _{G α}, i _{G β}After the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{gd}+}^{+}\\ i_{\mathrm{gq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]$

B6) i that step B4 is obtained _{G α}, i _{G β}Through the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{gd}-}^{-}\\ i_{\mathrm{gq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{g\&alpha;}}\\ i_{\mathrm{g\&beta;}}\end{array}\right]$

B7) with the stator three-phase current signal i that collects _Sa, i _Sb, i _ScPermanent Power Conversion obtains the current i under the α β axle system to the static two phase α β systems of axis through static abc three phase coordinate systems _{S α}, i _{S β}Wherein, static abc three phase coordinate systems to the permanent Power Conversion formula of the static two phase α β systems of axis are:

$\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \sqrt{\frac{3}{4}}& -\sqrt{\frac{3}{4}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{sa}}\\ i_{\mathrm{sb}}\\ i_{\mathrm{sc}}\end{array}\right]$

B8) i that step B7 is obtained _{S α}, i _{S β}After the static two phase α β systems of axis arrive the conversion of forward synchronous angular velocity rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the forward synchronous rotating frame after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to forward synchronous angular velocity rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{sd}+}^{+}\\ i_{\mathrm{sq}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& \sin \left({\mathrm{\&theta;}}_g\right)\\ -\sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]$

B9) i that step B7 is obtained _{S α}, i _{S β}Through the static two phase α β systems of axis after the conversion of reverse sync angular speed rotating coordinate system, again through obtaining generator unit stator electric current dq axle component under the reverse sync rotating coordinate system after the 2 ω trapper filtering

With

Wherein: the static two phase α β systems of axis to reverse sync angular speed rotating coordinate system transformation for mula are:

$\left[\begin{array}{c}{i}_{\mathrm{sd}-}^{-}\\ i_{\mathrm{sq}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& \sin (-{\mathrm{\&theta;}}_g)\\ -\sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\&alpha;}}\\ i_{\mathrm{s\&beta;}}\end{array}\right]$

B10) DC bus-bar voltage of parallelly connected grid side converter is regulated and is adopted pi regulator control; Its adjuster output and DC bus-bar voltage set-point constitute DC bus-bar voltage average active power set-point, that is:

$P_{g\_\mathrm{av}}^{*}=(K_{\mathrm{pu}}+K_{\mathrm{iu}}/s)(U_{\mathrm{dc}}^{*}-U_{\mathrm{dc}})\&CenterDot;U_{\mathrm{dc}}^{*}$

Wherein:

Represent that parallelly connected grid side converter keeps DC bus-bar voltage and stablize the instruction of required average active power,

Be DC bus-bar voltage set-point, K _PuAnd K _IuBe respectively DC bus-bar voltage adjuster proportionality coefficient and integral coefficient;

B11) parallelly connected grid side converter adopts the positive sequence line voltage to be oriented to the d axle; Then at this moment, system's positive and negative preface electric current set-point that the inhibition system always exports reactive power pulsation is:

$\left[\begin{array}{c}{i}_{\mathrm{gd}+}^{+*}\\ i_{\mathrm{gq}+}^{+*}\\ i_{\mathrm{gd}-}^{-*}\\ i_{\mathrm{gq}-}^{-*}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{gd}+}^{+}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}-\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}\\ -\frac{u_{\mathrm{gd}+}^{+}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\\ -\frac{k_1\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{k_2\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}-\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\\ \frac{k_3\&CenterDot;Q_{\mathrm{series}\_\cos 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{k_1\&CenterDot;Q_{\mathrm{series}\_\sin 2}}{{\left(u_{g+}^{+}\right)}^4-{\left(u_{g-}^{-}\right)}^4}+\frac{u_{\mathrm{gq}-}^{-}\&CenterDot;P_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2+{\left(u_{g-}^{-}\right)}^2}+\frac{u_{\mathrm{gd}-}^{-}\&CenterDot;Q_{g\_\mathrm{av}}^{*}}{{\left(u_{g+}^{+}\right)}^2-{\left(u_{g-}^{-}\right)}^2}\end{array}\right]$

Wherein:

$u_{g+}^{+}=u_{\mathrm{gd}+}^{+}$

${\left(u_{g-}^{-}\right)}^2={\left(u_{\mathrm{gd}-}^{-}\right)}^2+{\left(u_{\mathrm{gq}-}^{-}\right)}^2$

$Q_{g\_\mathrm{av}}^{*}=0$

$Q_{\mathrm{series}\_\cos 2}=-u_{\mathrm{gq}-}^{-}\&CenterDot;i_{\mathrm{sd}+}^{+}+u_{\mathrm{gd}-}^{-}\&CenterDot;i_{\mathrm{sq}+}^{+}$

$Q_{\mathrm{series}\_\sin 2}=u_{\mathrm{gd}-}^{-}\&CenterDot;i_{\mathrm{sd}+}^{+}+u_{\mathrm{gq}-}^{-}\&CenterDot;i_{\mathrm{sq}+}^{+}$

$k_1=-{2u}_{\mathrm{gd}+}^{+}\&CenterDot;u_{\mathrm{gd}-}^{-}\&CenterDot;u_{\mathrm{gq}-}^{-}$

$k_2={\left(u_{\mathrm{gd}+}^{+}\right)}^3-u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gd}-}^{-}\right)}^2+u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gq}-}^{-}\right)}^2$

$k_3=-({\left(u_{\mathrm{gd}+}^{+}\right)}^3-{u_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gq}-}^{-}\right)}^2+u}_{\mathrm{gd}+}^{+}\&CenterDot;{\left(u_{\mathrm{gd}-}^{-}\right)}^2)$

B12) under unbalanced electric grid voltage; Parallelly connected grid side converter is adopted the current on line side control under pair synchronization rotational coordinate axs system; Adopt electrical network positive sequence voltage oriented approach, the positive-negative sequence control voltage equation of parallelly connected grid side converter in two synchronization rotational coordinate axs are is under the unbalanced electric grid voltage:

$\left\{\begin{array}{c}{u}_{d+}^{+}=-(K_{p2+}+K_{i2+}/s)(i_{\mathrm{gd}+}^{+*}-i_{\mathrm{gd}+}^{+})+{\mathrm{\&omega;L}}_g{i}_{\mathrm{gq}+}^{+}+u_{\mathrm{gd}+}^{+}\\ u_{q+}^{+}=-(K_{p2+}+K_{i2+}/s)(i_{\mathrm{gq}+}^{+*}-i_{\mathrm{gq}+}^{+})-{\mathrm{\&omega;L}}_g{i}_{\mathrm{gd}+}^{+}\\ u_{d-}^{-}=-(K_{p2-}+K_{i2-}/s)(i_{\mathrm{gd}-}^{-*}-i_{\mathrm{gd}-}^{-})-{\mathrm{\&omega;L}}_g{i}_{\mathrm{gq}-}^{-}+u_{\mathrm{gd}-}^{-}\\ u_{q-}^{-}=-(K_{p2-}+K_{i2-}/s)(i_{\mathrm{gq}-}^{-*}-i_{\mathrm{gq}-}^{-})+{\mathrm{\&omega;L}}_g{i}_{\mathrm{gd}-}^{-}+u_{\mathrm{gq}-}^{-}\end{array}\right.$

Wherein: K _P2+And K _I2+Be respectively the proportionality coefficient and the integral coefficient of positive sequence voltage pi regulator, K _P2-And K _I2-Be respectively the proportionality coefficient and the integral coefficient of negative sequence voltage pi regulator, ω is synchronous electric angle speed, L _gBe parallelly connected grid side converter inlet wire reactor inductance;

B13) obtained in the step B12 positive sequence control voltage

The angular velocity of the rotating coordinate system forward synchronization to the stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinate shafting positive sequence under the control voltage

where:

The permanent Power Conversion that forward synchronous angular velocity rotational coordinates is tied to the static two phase α β systems of axis is:

$\left[\begin{array}{c}{u}_{\mathrm{\&alpha;}+}^{+}\\ u_{\mathrm{\&beta;}+}^{+}\end{array}\right]=\left[\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_g\right)& -\sin \left({\mathrm{\&theta;}}_g\right)\\ \sin \left({\mathrm{\&theta;}}_g\right)& \cos \left({\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{d+}^{+}\\ u_{q+}^{+}\end{array}\right]$

B14) obtained in the step B12 negative sequence control voltage

The angular velocity of the rotating coordinate system reverse synchronization to a stationary two-phase αβ coordinate transform constant power shaft stationary two-phase αβ coordinates shafting negative sequence under the control voltage

where: reverse synchronization angular velocity rotating coordinate system to a stationary two-phase αβ coordinate shafting constant power conversion is:

$\left[\begin{array}{c}{u}_{\mathrm{\&alpha;}-}^{-}\\ u_{\mathrm{\&beta;}-}^{-}\end{array}\right]=\left[\begin{array}{cc}\cos \left({-\mathrm{\&theta;}}_g\right)& -\sin \left({-\mathrm{\&theta;}}_g\right)\\ \sin \left({-\mathrm{\&theta;}}_g\right)& \cos \left({-\mathrm{\&theta;}}_g\right)\end{array}\right]\left[\begin{array}{c}{u}_{d-}^{-}\\ u_{q-}^{-}\end{array}\right]$

B15) with step B13, the resulting positive-negative sequence control of B14 voltage

With dc voltage U _DcProduce parallelly connected grid side converter PWM drive signal through space vector modulation.

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