CN101145751A - Current non-delay control method of AC excitation double-fed asynchronous wind power generator rotor - Google Patents

Abstract

The invention discloses a method for controlling rotor current of an AC excitation asynchronous doubly-fed induction generator (DFIG) without time delay. The method comprises acquiring a three-phase rotor current signal to perform rotational coordinate conversion to obtain rotor current feedback quantity in a positive rotation synchronous rotating coordinate system, compared with the rotor current command in the same coordinate system, inputting the error signal to a proportion-integral regulator for regulation, performing feedback compensation and decoupling to obtain rotor reference voltage in the positive rotation synchronous rotating coordinate system, converting to the rotor reference voltage for space vector pulse width modulation in a rotor coordinate system, and generating a switching signal for power devices of a rotor side transformer to control on-line operation of DFIG . The inventive method does not require performing positive and negative sequence decomposition of rotor current neither under balanced network voltage nor under imbalanced network voltage, and does not cause decomposition delay, so as to realize enhanced control target of the power generation system under imbalanced network voltage and effectively improve the uninterrupted operation (passing through) ability of the power generation system under network failure.

Description

The AC excitation double-fed asynchronous wind power generator rotor current non-delay control method

Technical field

The present invention relates to the control method of wind power generator rotor current, especially a kind ofly be applicable to AC excitation double-fed asynchronous wind power generator (DFIG) rotor current non-delay control method under line voltage balance and imbalance (comprising little value stable state and the big value transient state imbalance) condition.

Background technology

Modern large-scale wind powered generation syst mainly contains two types of double-fed asynchronous generator (DFIG) and magneto alternators, is to improve generating efficiency, all carries out variable speed constant frequency generator and moves, and wherein the DFIG system is current mainstream model.The wind power technology of China rests on the operation control under the desirable electrical network condition mostly at present, because actual electric network often has all kinds of symmetries, unbalanced fault to take place, therefore must carry out the operation Control Study under the electric network fault and propose corresponding control method.In recent years in the world the research of DFIG wind-powered electricity generation running technology focus mostly under symmetric fault operation control with pass through operation, but the electrical network unbalanced fault is more frequent, probability is bigger, so the research of DFIG failure operation is extended to unbalanced fault from symmetric fault.This be because in the DFIG control system if do not consider the imbalance of line voltage, very little unbalance voltage will cause the height imbalance of stator current, cause stator winding to produce uneven heating, generator produces torque pulsation, and the power that causes transferring to electrical network vibrates.If the relative net capacity of wind-powered electricity generation unit is enough big, the wind-powered electricity generation unit of this shortage unbalanced electric grid voltage control ability off-the-line from electrical network of having to is in case cause follow-up bigger electric network fault.But require the wind-powered electricity generation unit can bear the stable state of up 2% and relatively large transient state unbalance voltage again from the power grid security angle and do not withdraw from electrical network, this just requires the wind-powered electricity generation unit can realize that electric network fault passes through operation.At present, the home and abroad to the control method of DFIG generator under this unbalanced electric grid voltage condition and relevant excitation converter and embodiment research seldom, the relevant patent that retrieves with study article and only have:

I. Hu Jiabing, He Yikang etc. the modeling of double-fed asynchronous wind generator system and control under the unbalanced electric grid voltage condition. Automation of Electric Systems, 2007,31 (14): 47-56.

II.L?Xu，and?Y.?Wang，“Dynamic?Modeling?and?Control?of?DFIG?Based?WindTurbines?under?Unbalanced?Network?Conditions，”IEEE?Trans.Power?System，Vo1.22，No.1，pp.314-323，Feb.2007.

III.CARTWRIGHTP，XU?L.System?controller?tor?e.g.wind?powered?doublyfed?induction?generator?attached?to?wind?turbine，has?grid?imbalance?detector?whichcontrols?current?to?cancel?imbalance?in?grid?served?by?generators[Patent].PatentNumber.·GB2420456-A.Date.·20060524.Application?Number.·GB025662.Date.·20041123.

Under the unbalanced electric grid voltage condition, the available Fig. 1 of the control method that above-mentioned document proposed (can be described as conventional method) illustrates, the rotor-side converter 1 of DFIG5 adopts two proportional-integral controllers 16 respectively the positive and negative preface electric current of rotor to be done independent control.But for realizing the adjusting respectively of positive and negative preface rotor current, must at first obtain to feed back the positive and negative preface component of rotor current, its processing procedure is: utilize two current Hall transducers 2 to gather three-phase stator and rotor current signal respectively, voltage hall sensor 7 is gathered threephase stator voltage signal, the three-phase stator and rotor current signal I that collects _SabcAnd I _Rabc, stator voltage signal V _SabcPass through static three-phase/two-phase coordinate transformation module 3 respectively, be converted to the synthetic vector I that comprises positive and negative preface component _{S α β} ^sAnd I ^r _{R α β}, V _{S α β} ^s, V wherein _{S α β} ^s, I _{S α β} ^sBe converted to forward and backward with the V that comprises DC quantity and two frequency multiplication of ac sums in the leg speed rotating coordinate system by rotating coordinate transformation module 8,9 respectively _Sdq ⁺, V _Sdq ^-, I _Sdq ⁺, I _Sdq ^-(under the unbalanced source voltage condition), I _{R α β} ^rBy 10,11 conversions of two different rotating coordinate transformation modules, obtain forward and backward respectively with the I that comprises DC quantity and two frequency multiplication of ac sums in the leg speed rotating coordinate system _Rdq ⁺, I _Rdq ^-(under the unbalanced source voltage condition).Twice mains frequency 2 ω have been adopted in this method _sTrapper come filtered signal V _Sdq ⁺, V _Sdq ^-, I _Sdq ⁺, I _Sdq ^-And I _Rdq ⁺, I _Rdq ^-In 2 ω _sThe alternating component of frequency, wherein V _Sdq ⁺, V _Sdq ^-, I _Sdq ⁺, I _Sdq ^-Obtain its positive and negative preface component V respectively by first trapper 13-1 _Sdq+ ⁺, V _Sdq- ^-, I _Sdq+ ⁺, I _Sdq- ^-(DC quantity); I _Rdq ⁺, I _Rdq ^-Obtain its positive and negative preface component I respectively by second trapper 13-2 _Rdq+ ⁺, I _Rdq- ^-(DC quantity).On this basis, stator flux observer 14 obtains the required stator magnetic linkage component ψ of rotor current command value computing module 15 and feedback compensation decoupling zero module 12 _Sdq+ ⁺, ψ _Sdq- ^-Calculate acquisition rotor current instruction I according to the controlled target that DFIG is different under the unbalanced source voltage condition by rotor current command value computing module 15 _Rdq+ ^{+ *}, I _Rdq- ^*-, and with the feedback signal I of second trapper 13-2 output _Rdq+ ⁺, I _Rdq- ^-Relatively obtain error signal, then respectively forward and backward with the leg speed rotating coordinate system in 16 pairs of error signals of employing ratio-integrator make ratio-integration and regulate, signal after the adjusting obtains forward and backward with the positive and negative preface rotor voltage reference value V in the leg speed rotating coordinate system through feedback compensation decoupling zero module 12 compensated decouplings _Rdq+ ^{+ *}, V _Rdq- ^-*, be converted to positive and negative preface rotor voltage reference value in the rotor coordinate system by different rotating coordinate transformation modules 17,18 respectively, and obtain the reference signal V of space vector pulse width modulation (SVPWM) module 19 after the addition _{R α β} ^R*19 modulation obtain the switching signal of power device in the rotor-side converter 1 with control DFIG operation through the SVPWM module, realize the independent closed-loop control of the positive and negative preface rotor current of DFIG in the forward and backward synchronous rotating frame under the unbalanced electric grid voltage condition, reach the desired control target.

In addition, this method adopts software phase-lock loop (PLL) 6 circuit that the frequency and the phase place of line voltage are carried out accurate detection and tracking, rotor-position and speed adopt encoder 4 to measure, and realize the forward and backward rotating coordinate transformation for stator and rotor voltage, current signal foundation is provided.

By above-mentioned analytic process as seen, the essence of traditional DFIG control method is asymmetric system to be resolved into positive and negative ordered pair weigh after the system under the unbalanced source voltage condition, realizes d, the control of q decoupler shaft more respectively in the forward and backward synchronous rotating frame.Though the positive and negative preface electric current of rotor shows as DC quantity separately in the forward and backward synchronous rotating frame, adopt two pi regulators can realize the independently tracked control of floating respectively, but the prerequisite that control is implemented is to have realized the positive and negative preface of gathering rotor current is separated.2 ω have generally been adopted in positive and negative preface separation in traditional control method shown in Figure 1 _sFrequency trap 13 (or low pass filter or the time-delay of 1/4 line voltage primitive period etc.) method.Except that introducing time-delay, the bandwidth of control system will be affected, and can cause dynamic tracking error in the separation, and it is undesirable dynamically to control effect.What is more, and it is balance or imbalance that this circuit can't be distinguished line voltage, whether needs to carry out positive and negative preface system decomposition.If DFIG operates under the strict line voltage poised state, control system will adopt trapper to come the separation rotor variable, and this will bring unnecessary time-delay to the normal control of system, have a strong impact on the dynamic control performance of system.

Therefore, need badly and explore a kind of positive and negative preface rotor current control method of not having time-delay, to adapt to the operation control of DFIG wind-powered electricity generation unit under grid balance and the uneven condition.

Summary of the invention

The purpose of this invention is to provide a kind of AC excitation double-fed asynchronous wind power generator rotor current non-delay control method that the positive and negative preface of rotor current is decomposed that under unbalanced electric grid voltage, need not to carry out.This method also can not introduced the control time-delay because of unnecessary positive and negative preface operation splitting under the strict balance of line voltage, thereby effectively improve the operation control performance of DFIG wind power system under all kinds of line voltage conditions, the operation stability and the safety of guarantee the to power quality of power supply and electric power system.

Technical solution of the present invention is the AC excitation double-fed asynchronous wind power generator rotor current non-delay control method, may further comprise the steps:

(i) utilize two current Hall transducers to gather the threephase stator electric current I respectively _SabcWith rotor current signal I _Rabc, voltage hall sensor is gathered threephase stator voltage signal V _Sabc

The threephase stator voltage signal V that (ii) collects _SabcDetect electrical network/stator voltage angular frequency through software phase-lock loop _sAnd phase theta _sMeanwhile adopt encoder to detect the DFIG rotor position _rAnd rotational speed omega _rOn this basis through calculating slippage angle ± θ through the plus-minus calculator respectively _s-θ _rWith the slippage angular frequency _Slip+=ω _s-ω _r, ω _Slip-=-ω _s-ω _r

(iii) with the three-phase stator and rotor current signal I that collects _Sabc, I _RabcWith stator voltage signal V _SabcPass through static three-phase/two-phase coordinate transformation module respectively, obtain comprising the stator voltage synthetic vector V of positive and negative preface component _{S α β} ^s, stator and rotor electric current synthetic vector I _{S α β} ^sAnd I _{R α β} ^r

(iv) with stator voltage, electric current synthetic vector V in the stator rest frame that obtains _{S α β} ^s, I _{S α β} ^sAll, obtain respectively under the unbalanced source voltage condition, just changeing with containing DC quantity and two frequencys multiplication, 2 ω in the leg speed rotating coordinate system by just changeing with leg speed rotating coordinate transformation module _sThe voltage vector V of of ac sum _Sdq ⁺, current phasor I _Sdq ⁺, with stator voltage synthetic vector V _{S α β} ^sObtain under the unbalanced source voltage condition, containing DC quantity and two frequencys multiplication, 2 ω in the counter-rotating synchronous rotating frame with leg speed rotational coordinates module by counter-rotating _sThe voltage vector V of of ac sum _Sdq ^-

(v) adopt 2 ω of twice mains frequency _sTrapper filtering forward and backward is with voltage vector V in the leg speed rotating coordinate system _Sdq ⁺, V _Sdq ^-In 2 ω _sThe frequency alternating component obtains positive and negative sequence voltage DC component Vs _Dq+ ⁺, Vs _Dq- ^-

(vi) adopt stator flux observer to obtain rotor current command value computing module and calculate stator magnetic linkage DC component ψ in the required forward and backward synchronous rotating frame _Sdq+ ⁺, ψ _Sdq- ^-, and feedback compensation decoupling zero module compensates required just commentaries on classics with stator magnetic linkage component ψ in the leg speed rotating coordinate system _Sdq ⁺

(vii) with the rotor current synthetic vector I that obtains _{R α β} ^rThrough the rotating coordinate transformation module converts for just to change with the rotor current amount I in the leg speed rotating coordinate system _Rdq ⁺, it is just changeing under the unbalanced source voltage condition and is including positive sequence flip-flop I in the synchronous rotating frame _Rdq+ ⁺With twice mains frequency 2 ω _sNegative phase-sequence alternating component I _Rdq- ^-e ^{-j2 ω st}

(, calculate forward and backward with the instruction of the rotor current in leg speed rotating coordinate system I by rotor current command value computing module viii) according to the required controlled target of DFIG under the unbalanced source voltage condition _Rdq+ ^{+ *}, Ir _Dq- ^-*, with this current instruction value I _Rdq+ ^{+ *}, I _Rdq- ^-*Process rotating coordinate transformation module converts is for just to change with the rotor current command value I in the leg speed rotating coordinate system _Rdq ^{+ *}, and with just change with the rotor current feedback signal I in the leg speed rotating coordinate system _Rdq ⁺Relatively obtain error signal Δ I _Rda ⁺

(ix) rotor current error signal Δ I _Rda ⁺Do ratio-integration-resonance adjusting through just changeing, regulate back output signal U r with the ratio-integration in the leg speed rotating coordinate system-resonant controller _Da ^{+ *}Process feedback compensation decoupling zero module is finished and is just changeed with cross decoupling between friendship-d-axis and dynamic feedback compensation in the leg speed rotating coordinate system, obtains the rotor voltage reference value V that just changes with in the leg speed rotating coordinate system _Rdq ^{+ *}

(x) just changeing with the rotor voltage reference value V in the leg speed rotating coordinate system _Rdq ^{+ *}By the rotating coordinate transformation module, obtain the required rotor coordinate system rotor voltage reference signal V of space vector pulse width modulation module modulation _{R α β} ^R*, after this signal is modulated through the space vector pulse width modulation module, obtain the required rotor-side inverter power devices switch signal S of control DFIG operation _a, S _b, S _c

Above-mentioned steps (said controlled target is viii): or the output of maintenance DFIG stator has, reactive power is constant, or keep the DFIG electromagnetic torque constant, or keep stator current balance or rotor current balance.

The present invention is said just to be changeed with the ratio-integration in the leg speed rotating coordinate system-resonant controller, comprises that it is ω that a proportional component, integral element and one are just changeing with angular frequency in the leg speed rotating coordinate system _p=2 ω _sResonator, wherein the angular frequency resonator realizes that align commentaries on classics is 2 ω with angular frequency in the leg speed rotating coordinate system _sThe unlimited gain-adjusted of negative phase-sequence rotor current composition.

Control method of the present invention is based on just to change with the positive and negative preface electric current of the DFIG rotor in the leg speed rotating coordinate system and need not to decompose, do not have time-delay control.At different operation controlled target under the DFIG wind power system unbalanced electric grid voltage condition, by positive and negative preface electric current of unbalance voltage lower rotor part and the relation that has, reactive power is instructed, at first establish positive and negative preface rotor current command value, and it is converted into the global command value that comprises positive and negative preface rotor current of just changeing with in the leg speed rotating coordinate system by corresponding rotating coordinate transformation respectively.No matter the present invention all need not the rotor current feedback signal is carried out positive and negative preface decomposition when line voltage balance and imbalance in the control, only need by three-phase rotor current feedback signal is made corresponding rotating coordinate transformation, obtaining is just changeing with the rotor current feedback quantity in the leg speed rotating coordinate system.This signal all shows as DC quantity and twice mains frequency of ac sum with just changeing with the global command value in the leg speed rotating coordinate system, after both are compared, its error signal is input to ratio-integration-resonance (PIR) adjuster, output signal after Comparative Examples-integration-resonance current controller is regulated is carried out the feedback compensation decoupling zero, can just be changeed with the rotor voltage reference value in the leg speed rotating coordinate system, be converted into space vector pulse width modulation reference signal in the rotor coordinate system by rotating coordinate transformation again, generate the pwm switch signal of power device of inverter through ovennodulation, the output current wave and the amplitude of control rotor-side converter are to realize the operation controlled target of DFIG.

Control method of the present invention is simple.Than traditional control method, need not to increase extra hardware detection or controlling unit, only traditional forward and backward need be replaced with the positive and negative preface of the rotor current in the leg speed rotating coordinate system, two proportional-integral controller just changes with the single ratio-integration in the leg speed rotating coordinate system-resonance adjuster.When the rotor current control ring designs, because the positive and negative preface that need not to adopt filter to carry out the rotor current feedback signal is decomposed, can therefore not introduce and decompose time-delay, and integral element there is unlimited gain to flip-flop in the designed PIR controller, and twice mains frequency 2 ω _sThe resonance link only team to twice mains frequency 2 ω _sOf ac unlimited gain is arranged, when guaranteeing system stability, obtain the more control bandwidth of greater trochanter current closed-loop, thereby obtain stable output, less steady-state error and better dynamic response characteristic.Adopt this method can make the DFIG grid-connected system under line voltage balance and imbalance (comprising little value stable state and big value transient state imbalance) condition, realize that rotor current does not have time-delay control, especially under the unbalanced electric grid voltage condition, realize the enhancing controlled target of electricity generation system, effectively improve (passing through) ability that runs without interruption under such wind power system electric network fault.

The inventive method is except that being applicable to the DFIG wind power system, can also be applicable to three-phase or the effective control of single-phase grid-connected inverter under balance and unbalanced electric grid voltage condition that other adopt all kinds of PWM control forms of HF switch self-turn-off device formation, parallel network reverse device as solar energy, fuel cell generation, the electronic power inversion device of flexible transmission system, and the effective control of convertor assembly of the double-fed dynamoelectric machine in the speed governing Electric Drive.

Description of drawings

Fig. 1 is under the unbalanced electric grid voltage condition, AC excitation double-fed asynchronous generator tradition control method schematic diagram.

Fig. 2 is an AC excitation double-fed asynchronous wind power generator rotor current non-delay control method schematic diagram of the present invention.

Fig. 3 is the schematic diagram of the ratio-integration-resonant controller among the present invention.

Fig. 4 is with positive and negative preface rotor current command value I among Fig. 2 _Rdq+ ^{+ *}, I _Rdq- ^-*Be converted to the command value I that just changes with in the leg speed rotating coordinate system _{R α β} ^S*The rotating coordinate transformation module diagram.

Fig. 5 is under the uneven condition of line voltage transient state, adopts the design sketch of traditional control method, among the figure, and (a) DFIG stator three-phase current (pu); (b) rotor three-phase electric current (pu); (c) DC bus-bar voltage (V); (d) stator active power of output (pu); (e) stator output reactive power (pu); (f) DFIG electromagnetic torque (pu); (g) rotor d axle forward-order current I _Rd+ ^{+ *}And I _Rd+ ⁺(pu); (h) rotor q axle forward-order current I _Rq+ ^{+ *}And I _Rq+ ⁺(pu); (i) rotor d axle negative-sequence current I _Rd- ^-*And I _Rd- ^-(pu); (j) rotor q axle negative-sequence current I _Rq- ^-*And I _Rq- ^-(pu).

Fig. 6 is under the uneven condition of line voltage transient state, adopts the design sketch of control method of the present invention, among the figure, and (a) DFIG stator three-phase current (pu); (b) rotor three-phase electric current (pu); (c) DC bus-bar voltage (V); (d) stator active power of output (pu); (e) stator output reactive power (pu); (f) DFIG electromagnetic torque (pu); (g) rotor d axle forward-order current I _Rd+ ^{+ *}And I _Rd+ ^{+ *}(pu); (h) rotor q axle forward-order current I _Rq+ ^{+ *}And Ir _Q+ ⁺(pu); (i) rotor d axle negative-sequence current I _Rq- ^-*And I _Rq- ^-(pu); (j) rotor q axle negative-sequence current I _Rq- ^-*And I _Rq- ^-(pu).

Fig. 7 is the static α of stator _sβ _sCoordinate system, rotor speed rotation alpha _rβ _rCoordinate system and forward and backward are with leg speed ω _sVector correlation figure between rotation dq+, dq-coordinate system.

Embodiment

The present invention is further described below in conjunction with accompanying drawing and embodiment.

Fig. 2 is the schematic diagram that adopts the AC excitation double-fed asynchronous wind power generator rotor current non-delay control method of the present invention's proposition, comprise controlling object DFIG5, the rotor-side converter 1 that is connected with the DFIG rotor (two level or three level voltage type PWM inverters), be used for the Hall element 2 of three-phase stator and rotor current detecting and the Hall element 7 of threephase stator voltage detecting, be used to detect the encoder 4 of DFIG rotor-position and speed, and the control loop of realizing DFIG controlled target under the unbalanced source voltage condition.Control loop is made of feedback signal treatment channel and forward direction control channel, wherein the feedback signal treatment channel comprises the software phase-lock loop (PLL) 6 that is used for detection of grid voltage-phase and frequency, be used for the needed angle computer of various rotating coordinate transformations, be used for obtaining the three-phase/two-phase static coordinate conversion module 3 and the rotating coordinate transformation module 8 of corresponding coordinate system signal, 9,10, the stator flux observer 14 that is used to obtain the twice mains frequency trapper 13 of the positive and negative preface component of stator voltage and is used for stator flux observer; Forward direction control channel comprises the rotor current command value computing module 15 according to the required controlled target of unbalanced source voltage condition, will be just, counter-rotating is converted to the rotating coordinate transformation module 22 of just changeing with command value in the leg speed rotating coordinate system with the rotor current command value in the leg speed rotating coordinate system, the just commentaries on classics of rotor current not being had the time delay tracking Control is with ratio-integration-resonant controller (PIR) 21 in the leg speed rotating coordinate system with for obtaining just changeing the feedback decoupling compensating module 20 with leg speed rotating coordinate system rotor voltage reference value, be used for just changeing the rotating coordinate transformation module 17 that is converted to reference value in the rotor coordinate system with the rotor voltage reference value of leg speed rotating coordinate system, and the SVPWM module 19 that is used for producing according to the rotor voltage reference value space vector pulse width modulation (SVPWM) signal.

With the commercial variable speed constant frequency DFIG of 1.5MW wind power system is example, and with reference to Fig. 2, the method that adopts the present invention to propose is controlled its operation, and concrete implementation step is as follows:

(i) utilize two current Hall transducers 2 to gather threephase stator current signal I respectively _SabcWith rotor current signal I _Rabc, voltage hall sensor 7 is gathered threephase stator voltage signal V _Sabc

The threephase stator voltage signal V that (ii) collects _SabcDetect through software phase-lock loop 6, obtain electrical network/stator voltage angular frequency _sAnd phase theta _s, meanwhile adopt encoder 4 to detect the DFIG rotor position _rAnd rotational speed omega _rAnd calculate DFIG rotor slippage angle ± θ with angle computer respectively _s-θ _rWith the slippage angular frequency _Slip+=ω _s-ω _r, ω _Slip-=-ω _s-ω _r

(iii) with the three-phase stator and rotor current signal I that collects _Sabc, I _Rabc, stator voltage signal V _SabcPass through static three-phase/two-phase coordinate transformation module 3 respectively, obtain comprising the voltage synthetic vector V of positive and negative preface component _{S α β} ^s, electric current synthetic vector I _{S α β} ^sAnd I _{R α β} ^rWith the stator voltage is example, and its static three-phase/two-phase coordinate transform is as shown in the formula expression

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

(iv) with stator voltage, electric current synthetic vector V in the stator rest frame that obtains _{S α β} ^s, I _{S α β} ^sAll, obtain respectively under the unbalanced source voltage condition, just changeing and contain DC quantity and two frequencys multiplication, 2 ω in the synchronous rotating frame by just changeing with leg speed rotating coordinate transformation module 9 _sThe voltage vector V of of ac sum _Sdq ⁺, current phasor I _Sdq ⁺With stator voltage synthetic vector V _{S α β} ^s, obtain under the unbalanced source voltage condition, containing DC quantity and two frequencys multiplication, 2 ω in the counter-rotating synchronous rotating frame with leg speed rotational coordinates module 8 by counter-rotating _sThe voltage vector V of of ac sum _Sdq ^-

Fig. 7 is static α _sβ _sCoordinate system, spinner velocity rotation alpha _rβ _rCoordinate system and forward and backward are with leg speed ω _s(equal the angular frequency of electrical network/stator voltage with leg speed _s) rotating the vector correlation figure between dq+, dq-coordinate system, its coordinate transformation relation is

$F_{\mathrm{dq}}^{+}=F_{\mathrm{\α\β}}^s{e}^{-j{\mathrm{\ω}}_{s}t}$ $F_{\mathrm{dq}}^{-}=F_{\mathrm{\α\β}}^s{e}^{j{\mathrm{\ω}}_{s}t}$

$F_{\mathrm{dq}}^{+}=F_{\mathrm{\α\β}}^r{e}^{-j({\mathrm{\ω}}_s-{\mathrm{\ω}}_r)t}$ $F_{\mathrm{dq}}^{-}=F_{\mathrm{\α\β}}^r{e}^{j(-{\mathrm{\ω}}_s-{\mathrm{\ω}}_r)t}$

$F_{\mathrm{dq}}^{+}=F_{\mathrm{dq}}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$ $F_{\mathrm{dq}}^{-}=F_{\mathrm{dq}}^{+}{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">e</figure-callout>}}^j$

Wherein, broadly representative voltage, electric current and magnetic linkage of F; Subscript+,-, s, r represent that forward and backward is with leg speed rotating coordinate system, stator rest frame and rotor rotating coordinate system;

Under the unbalanced electric grid voltage condition, stator and rotor voltage, electric current and magnetic linkage can be expressed as forward and backward with leg speed ω _sThe form of corresponding positive and negative preface component in rotation dq+, the dq-coordinate system

$V_{\mathrm{sdq}}^{+}=V_{\mathrm{sdq}+}^{+}+V_{\mathrm{sdq}-}^{+}=V_{\mathrm{sdq}+}^{+}+V_{\mathrm{sdq}-}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$

$I_{\mathrm{sdq}}^{+}=I_{\mathrm{sdq}+}^{+}+I_{\mathrm{sdq}-}^{+}=I_{\mathrm{sdq}+}^{+}+I_{\mathrm{sdq}-}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$

${\mathrm{\&psi;}}_{\mathrm{sdq}}^{+}={\mathrm{\&psi;}}_{\mathrm{sdq}+}^{+}+{\mathrm{\&psi;}}_{\mathrm{sdq}-}^{+}={\mathrm{\&psi;}}_{\mathrm{sdq}+}^{+}+{\mathrm{\&psi;}}_{\mathrm{sdq}-}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$

$V_{\mathrm{rdq}}^{+}=V_{\mathrm{rdq}+}^{+}+V_{\mathrm{rdq}-}^{+}=V_{\mathrm{rdq}+}^{+}+V_{\mathrm{rdq}-}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$

$I_{\mathrm{rdq}}^{+}=I_{\mathrm{rdq}+}^{+}+I_{\mathrm{rdq}-}^{+}=I_{\mathrm{rdq}+}^{+}+I_{\mathrm{rdq}-}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$

${\mathrm{\&psi;}}_{\mathrm{rdq}}^{+}={\mathrm{\&psi;}}_{\mathrm{rdq}+}^{+}+{\mathrm{\&psi;}}_{\mathrm{rdq}-}^{+}={\mathrm{\&psi;}}_{\mathrm{rdq}+}^{+}+{\mathrm{\&psi;}}_{\mathrm{rdq}-}^{-}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">j</figure-callout>}2{\mathrm{\&omega;}}_{s}t}$

Wherein, subscript+, the corresponding positive and negative preface component of-expression.As seen, each electric weight is just changeing with leg speed ω under the unbalanced electric grid voltage _sShow as DC quantity and two frequencys multiplication, 2 ω in the rotation dq+ coordinate system _sThe of ac sum.With stator voltage Vs _Dq ⁺Be example, V _Sdq+ ⁺Be illustrated in the positive sequence component in the dq+ coordinate system, be DC quantity; V _Sdq- ⁺Being illustrated in the negative sequence component in the dq+ coordinate system, is two frequency multiplication of ac V _Sdq- ^-e ^{-j2 ω st}In like manner, each electric weight rotates in the dq-coordinate system with leg speed in counter-rotating and also shows as DC quantity and two frequency multiplication of ac sums;

(v) adopt 2 ω of twice mains frequency _sTrapper 13 filtering forward and backwards are with voltage vector V in the leg speed rotating coordinate system _Sdq ⁺, V _Sdq ^-In 2 ω _sThe frequency alternating component obtains positive and negative sequence voltage DC component V _Sdq+ ⁺, V _Sdq- ^-

(vi) adopt stator flux observer to obtain the stator magnetic linkage DC component ψ that rotor current command value computing module 15 calculates in the required forward and backward synchronous rotating frame _Sdq+ ⁺, ψ s _Dq- ^-, and feedback compensation decoupling zero module 20 compensates required just commentaries on classics with stator magnetic linkage component ψ in the leg speed rotation dq+ coordinate system _Sdq ⁺

(vii) with the rotor current synthetic vector I that obtains _{R α β} ^rBe converted to the rotor current amount I that just changes with in the leg speed rotation dq+ coordinate system through rotating coordinate transformation module 10 _Rdq ⁺, it includes positive sequence flip-flop I under the unbalanced source voltage condition _Rdq ⁺With twice mains frequency 2 ω _sNegative phase-sequence alternating component I _Rdq- ^-e ^{-j2 ω st}

Rotating coordinate transformation module 10 can be expressed with following formula

$\left[\begin{array}{c}{I}_{\mathrm{rd}}^{+}\\ I_{\mathrm{rq}}^{+}\end{array}\right]\left[\begin{array}{cc}\cos ({\mathrm{\&theta;}}_s-{\mathrm{\&theta;}}_r)& \sin ({\mathrm{\&theta;}}_s-{\mathrm{\&theta;}}_r)\\ -\sin ({\mathrm{\&theta;}}_s-{\mathrm{\&theta;}}_r)& \cos ({\mathrm{\&theta;}}_s-{\mathrm{\&theta;}}_r)\end{array}\right]\left[\begin{array}{c}{I}_{\mathrm{r\&alpha;}}^r\\ I_{\mathrm{r\&beta;}}^r\end{array}\right];$

Viii), calculate forward and backward with the instruction of the rotor current in leg speed rotating coordinate system I by rotor current command value computing module 15 according to the required controlled target of DFIG under the unbalanced source voltage condition _Rdq+ ^{+ *}, I _Rdq- ^-*, with this current instruction value I _Rdq+ ^{+ *}, I _Rda- ^-*Be converted to the rotor current command value I that just changes with in the leg speed rotation dq+ coordinate system through rotating coordinate transformation module 22 _Rda ^{+ *}, and with just change with the rotor current feedback signal I in the leg speed rotation dq+ coordinate system _Rdq ⁺Relatively obtain error signal Δ I _Rdq ⁺,

Rotating coordinate transformation module 22 as shown in Figure 4, available following formula is expressed

$\left[\begin{array}{c}{I}_{\mathrm{rd}}^{+*}\\ I_{\mathrm{rq}}^{+*}\end{array}\right]=\left[\begin{array}{c}{I}_{\mathrm{rd}+}^{+*}\\ I_{\mathrm{rq}+}^{+*}\end{array}\right]+\left[\begin{array}{cc}\cos \left(2{\mathrm{\&theta;}}_s\right)& \sin \left(2{\mathrm{\&theta;}}_s\right)\\ -\sin \left(2{\mathrm{\&theta;}}_s\right)& \cos \left(2{\mathrm{\&theta;}}_s\right)\end{array}\right]\left[\begin{array}{c}{I}_{\mathrm{rd}-}^{-*}\\ I_{\mathrm{rq}-}^{-*}\end{array}\right];$

(iX) rotor current error signal Δ I _Rda ⁺Do ratio-integration-resonance adjusting through just changeing, regulate the back output signal U with the ratio-integration in the leg speed rotating coordinate system-resonant controller 21 _Rda ^{+ *}Process feedback compensation decoupling zero module 20 is finished and is just changeed with cross decoupling and dynamic feedback compensation between the friendship-d-axis in the leg speed rotating coordinate system, obtains the rotor voltage reference value V that just changes with in the leg speed rotating coordinate system _Rdq ^{+ *}

As the above analysis, in the dq+ coordinate system, realize rotor current I _Rdq ⁺The floating tracking Control, must be to DC component I _Rdq+ ⁺With alternating current component I _Rdq- ^-e ^{-j2 ω st}Realize overall floating adjusting simultaneously.Thereby when design DFIG rotor current controller, adopt integral element, adopt 2 ω at the alternating component of twice mains frequency at flip-flop _sResonator has constituted rotor current ratio-integration-resonance (PIR) controller 21 with this, as shown in Figure 3.Ratio-integration among the figure-resonance (PIR) controller 21 bodies comprise a proportional component, an integral element and one 2 ω _sThe resonance link, realize rotor current error signal Δ I _Rdq ⁺=I _Rdq ^{+ *}-I _Rdq ⁺Floating regulate.

The frequency domain presentation of PIR current controller 21 is

$C_{\mathrm{pI}+R}\left(s\right)=K_{\mathrm{ip}}+\frac{K_{\mathrm{iI}}}{s}+\frac{s{K}_{\mathrm{iR}}}{s^2+{\left(2{\mathrm{\&omega;}}_s\right)}^2}$

In the formula, K _Ip, K _II, K _IRBe ratio, integration and resonance coefficient,

The output U of ratio-resonant controller _Rdq ^{+ *}Generate DFIG rotor voltage instruction V through compensation _Rdq ^{+ *}To produce rotor current I _Rdq ⁺, realize the operation control under the unbalanced electric grid voltage condition, in Fig. 3 control procedure $E_{\mathrm{rdq}}^{+}=\frac{L_m}{L_s}(V_{\mathrm{sdq}}^{+}-R_s{I}_{\mathrm{sdq}}^{+}-j{\mathrm{\&omega;}}_s{\mathrm{\&psi;}}_{\mathrm{sdq}}^{+})+j{\mathrm{\&omega;}}_{\mathrm{slip}}+{\mathrm{\&psi;}}_{\mathrm{rdq}}^{+}$ For equivalent back-emf disturbs, and F (s)=1/ (s σ L _r+ R _r) DFIG is the rotor Mathematical Modeling, in the formula, σ=1-L _m ²/ L _sL _r, L _m, L _s, L _rBe respectively DFIG mutual inductance, stator and rotor self-induction, R _rBe rotor resistance.

Just changeing with leg speed rotation dq+ coordinate system rotor voltage reference value and can be expressed as

$\left\{\begin{array}{c}{V}_{\mathrm{rd}}^{+*}=R_r{I}_{\mathrm{rd}}^{+}+U_{\mathrm{rd}}^{+*}\frac{L_m}{L_s}(V_{\mathrm{sd}}^{+}-R_s{I}_{\mathrm{sd}}^{+}+{\mathrm{\&omega;}}_s{\mathrm{\&psi;}}_{\mathrm{sq}}^{+})-{\mathrm{\&omega;}}_{\mathrm{slip}}+{\mathrm{\&psi;}}_{\mathrm{rq}}^{+}\\ V_{\mathrm{rq}}^{+*}=R_r{I}_{\mathrm{rq}}^{+}+U_{\mathrm{rq}}^{+*}\frac{L_m}{L_s}(V_{\mathrm{sq}}^{+}-R_s{I}_{\mathrm{sq}}^{+}-{\mathrm{\&omega;}}_s{\mathrm{\&psi;}}_{\mathrm{sd}}^{+})+{\mathrm{\&omega;}}_{\mathrm{slip}}+{\mathrm{\&psi;}}_{\mathrm{rd}}^{+}\end{array}\right.$

Wherein, $\left\{\begin{array}{c}{U}_{\mathrm{rd}}^{+*}=\frac{d}{\mathrm{dt}}{I}_{\mathrm{rd}}^{+}=C_{\mathrm{PI}+R}\left(s\right)(I_{\mathrm{rd}}^{+*}-I_{\mathrm{rd}}^{+})\\ U_{\mathrm{rq}}^{+*}=\frac{d}{\mathrm{dt}}{I}_{\mathrm{rq}}^{+}=C_{\mathrm{PI}+R}\left(s\right)(I_{\mathrm{rq}}^{+*}-I_{\mathrm{rq}}^{+})\end{array}\right.,$ R _sBe stator resistance;

(x) just changeing with the rotor voltage reference value V in the leg speed rotating coordinate system _Rdq ^{+ *}After rotating coordinate transformation module 17, obtain the required rotor coordinate system rotor voltage reference signal V of space vector pulse width modulation module 19 modulation _{R α β} ^R*, after this signal is modulated through space vector pulse width modulation module 19, the switching signal S of power device in the rotor-side converter 1 of acquisition control DFIG operation _a, S _b, S _c

Said controlled target is among the above-mentioned steps viii: or the output of maintenance DFIG stator has, reactive power is constant, or keep the DFIG electromagnetic torque constant, or keep stator current balance or rotor current balance etc.Adopt positive sequence stator voltage V _Sd ⁺During vector oriented control, several different controlled target lower rotor part current instruction values can be expressed as:

I, maintenance DFIG active power of output balance, i.e. P _Ssin2=P _Scos2=0, then

$I_{\mathrm{rd}+}^{+*}=\frac{L_s{V}_{\mathrm{sd}+}^{+}}{L_m{D}_3}{P}_{s0}-\frac{4V_{\mathrm{sd}+}^{+}{V}_{\mathrm{sd}-}^{-}{V}_{\mathrm{sq}-}^{-}}{D_3{L}_m},$ $I_{\mathrm{rq}+}^{+*}=\frac{L_s{V}_{\mathrm{sd}+}^{+}(Q_{s0}+\frac{D_3}{L_s})}{L_m{D}_2}-\frac{2V_{\mathrm{sd}+}^{+}}{D_2{L}_m}(V_{\mathrm{sd}-}^{-2}-V_{\mathrm{sq}-}^{-2})$

$I_{\mathrm{rd}-}^{-*}=2V_{\mathrm{sq}-}^{-}/L_m-k_{\mathrm{dd}}{I}_{\mathrm{rd}+}^{+*}-k_{\mathrm{qd}}{I}_{\mathrm{rq}+}^{+*},$ $I_{\mathrm{rq}-}^{-*}=-2V_{\mathrm{sd}-}^{-}/L_m-k_{\mathrm{qd}}{I}_{\mathrm{rd}+}^{+*}+k_{\mathrm{dd}}{I}_{\mathrm{rq}+}^{+*}$

Wherein, ${\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=V_{\mathrm{sd}+}^{+2}+V_{\mathrm{sd}-}^{-2}+V_{\mathrm{sq}-}^{-2},{\mathrm{<figure-callout\; id="3"\; label="D"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">D</figure-callout>}}_3=V_{\mathrm{sd}+}^{+2}-(V_{\mathrm{sd}-}^{-2}+V_{\mathrm{sq}-}^{-2}),$ $k_{\mathrm{dd}}=V_{\mathrm{sd}-}^{-}/V_{\mathrm{sd}+}^{+},k_{\mathrm{qd}}=V_{\mathrm{sq}-}^{-}/V_{\mathrm{sd}+}^{+},$ P _Sc ^*, Q _S0 ^*Be respectively that DFIG output on average has, the command value of reactive power;

II, maintenance rotor current do not have negative sequence component, i.e. I _Rd ^-=I _Rq ^-=0, then

$I_{\mathrm{rd}+}^{+*}=\frac{L_s{P}_{s0}}{L_m{V}_{\mathrm{sd}+}^{+}},$ $I_{\mathrm{rq}}^{+*}=-\frac{L_s(Q_{s0}+\frac{D_3}{L_s})}{L_m{V}_{\mathrm{sd}+}^{+}};$

III, maintenance stator current balance, promptly $I_{\mathrm{sd}-}^{-}=I_{\mathrm{sq}-}^{-}=0,$ Then

$I_{\mathrm{rd}+}^{+*}=\frac{L_s{P}_{s0}}{L_m{V}_{\mathrm{sd}+}^{+}},$ $I_{\mathrm{rq}+}^{+*}=-\frac{L_s(Q_{s0}+\frac{D_3}{L_s})}{L_m{V}_{\mathrm{sd}+}^{+}}$

$I_{\mathrm{rd}-}^{-*}=-V_{\mathrm{sq}-}^{-}/L_m,$ $I_{\mathrm{rq}-}^{-*}=V_{\mathrm{sd}-}^{-}/L_m;$

IV, maintenance DFIG electromagnetic torque and output reactive power are constant, i.e. P _Esin2=P _Ecos2=0, then

$I_{\mathrm{rd}+}^{+*}=\frac{L_s{V}_{\mathrm{sd}+}^{+}}{L_m{D}_2}{P}_{s0},$ $I_{\mathrm{rq}+}^{+*}=-\frac{L_s{V}_{\mathrm{sd}+}^{+}(Q_{s0}+\frac{D_3}{L_s})}{{\mathrm{<figure-callout\; id="3"\; label="L\; m\; D"\; filenames="A20071007065700171.png"\; state="\{\{state\}\}">L</figure-callout>}}_m{D}_{}{}_3}$

$I_{\mathrm{rd}-}^{-*}=k_{\mathrm{dd}}{I}_{\mathrm{rd}+}^{+*}+k_{\mathrm{qd}}{I}_{\mathrm{rq}+}^{+*},$ $I_{\mathrm{rq}-}^{-*}=k_{\mathrm{qd}}{I}_{\mathrm{rd}+}^{+*}-k_{\mathrm{dd}}{I}_{\mathrm{rq}+}^{+*}.$

Comparison diagram 2 and Fig. 1 as can be seen, embodiment proposed by the invention calculate forward and backward with the leg speed rotating coordinate system in each positive and negative preface rotor current command value I _Rdq+ ^{+ *}, I _Rdq- ^-*The time, though still need adopt trapper 13 to obtain the positive and negative preface component of stator voltage, but the time-delay that this trapper 13 is introduced is outside the rotor current control ring, thereby can not influence the bandwidth and the dynamic responding speed of ring control in the rotor current, because the response speed of whole system is mainly by ring decision in the rotor current control, so the time-delay of introducing when adopting trapper 13 to obtain the positive and negative preface component of stator voltage is very little to its influence.In addition, all need not to do positive and negative preface phase sequence in this method under the unbalanced source voltage condition when rotor current is regulated decomposes, in just changeing, adopt integral operation, adopted 2 ω at the alternating component of twice mains frequency at flip-flop with leg speed rotation dq+ coordinate system _sResonator, and 2 ω _sResonator is only to 2 ω _sAlternating component on the Frequency point has unlimited gain.Under the situation of the strict balance of line voltage, because rotor current only has positive sequence component in just changeing with leg speed rotation dq+ coordinate system, promptly in just changeing, show as single flip-flop with the leg speed rotational coordinates, integral element can realize the floating of rotor current is regulated control in the PIR controller at this moment, so the present invention can be suitable for effective control of AC excitation double-fed asynchronous wind power generator (DFIG) rotor current under line voltage balance and imbalance (comprising little value stable state and the big value transient state imbalance) condition simultaneously.

Fig. 5 and Fig. 6 are respectively and adopt DFIG tradition control method and the result of implementation of control method of the present invention under transient grid Voltage unbalance condition relatively.At 0.4s moment line voltage generation unbalanced fault, line voltage recovers during 0.8s.In this case study on implementation, choose and keep electromagnetic torque constant to alleviate mechanical stress to blower fan system as the controlled target of DFIG under unbalance voltage.As can be seen with just traditional, negative phase-sequence, the DFIG control method of two proportional-integral controllers relatively, (0.4s) and removing (0.8s) moment take place at the line voltage unbalanced fault, the inventive method need not DFIG wind power system rotor electric current is just being implemented, negative sequence component decomposes, realized nothing time-delay overall situation control to rotor current, as figure (g) among Fig. 6, figure (h), figure (i), figure (j), thereby realized that fast (during 0.4s～0.8s) keeps the constant controlled target of DFIG controlling electromagnetic torque under the unbalanced source voltage condition, also ripple disable of DFIG stator output reactive power simultaneously is as figure (e) among Fig. 6, shown in the figure (f).Meanwhile when the line voltage fault clearance, control system can return under the symmetrical operation state fast, reposefully, and under the strict balance of line voltage, also can not bring unnecessary decomposition and introduce corresponding time-delay to system, thereby improved the operation control ability of DFIG wind power system under various electrical network conditions, improve the dynamic quality of control system, realized the operation of passing through under the electric network fault.

Claims (3)

1. AC excitation double-fed asynchronous wind power generator rotor current non-delay control method is characterized in that may further comprise the steps:

(i) utilize two current Hall transducers (2) to gather the threephase stator electric current I respectively _SabcWith rotor current signal I _Rabc, voltage hall sensor (7) is gathered threephase stator voltage signal V _Sabc

The threephase stator voltage signal V that (ii) collects _SabcDetect through software phase-lock loop (6), obtain electrical network/stator voltage angular frequency _sAnd phase theta _sMeanwhile adopt encoder (4) to detect DFIG rotor position angle θ _rAnd rotational speed omega _rAnd calculate slippage angle ± θ through the plus-minus calculator respectively _s-θ _rWith the slippage angular frequency _Slip+=ω _s-ω _r, ω _SlipThe ω of-=- _s-ω _r

(iii) with the three-phase stator and rotor current signal I that collects _Sabc, I _RabcWith stator voltage signal V _SabcPass through static three-phase/two-phase coordinate transformation module (3) respectively, obtain comprising the stator voltage synthetic vector V of positive and negative preface component _{S α β} ^s, stator and rotor electric current synthetic vector I _{S α β} ^sAnd I _{R α β} ^r

(iv) with stator voltage, electric current synthetic vector V in the stator rest frame that obtains _{S α β} ^s, I _{S α β} ^sAll, obtain respectively under the unbalanced source voltage condition, just changeing with containing DC quantity and two frequencys multiplication, 2 ω in the leg speed rotating coordinate system by just changeing with leg speed rotating coordinate transformation module (9) _sThe voltage vector V of of ac sum _Sdq ⁺, current phasor I _Sdq ⁺, again with stator voltage synthetic vector V _{S α β} ^s, obtain under the unbalanced source voltage condition, reversing with leg speed rotational coordinates module (8) by counter-rotating with containing DC quantity and two frequencys multiplication, 2 ω in the leg speed rotating coordinate system _sThe voltage vector V of of ac sum _Sdq ^-

(v) adopt 2 ω of twice mains frequency _sTrapper (13) filtering forward and backward is with voltage vector V in the leg speed rotating coordinate system _Sdq ⁺, V _Sdq ^-In 2 ω _sThe frequency alternating component obtains positive and negative sequence voltage DC component V _Sdq+ ⁺, V _Sdq- ^-

(vi) adopt stator flux observer (14), obtain the stator magnetic linkage DC component ψ in the required forward and backward synchronous rotating frame of rotor current command value computing module (15) calculating _Sdq+ ⁺, ψ _Sdq- ^-, and feedback compensation decoupling zero module (20) compensates required just commentaries on classics with stator magnetic linkage component ψ in the leg speed rotating coordinate system _Sdq ⁺

(vii) with the rotor current synthetic vector I that obtains _{R α β} ^rBe converted to the rotor current amount I that just changes with in the leg speed rotating coordinate system through rotating coordinate transformation module (10) _Rdq ⁺, it includes positive sequence flip-flop I under the unbalanced source voltage condition _Rdq+ ⁺With twice mains frequency 2 ω _sNegative phase-sequence alternating component I _Rdq- ^-e ^{-j2 ω st}

(, calculate forward and backward with the instruction of the rotor current in leg speed rotating coordinate system I by rotor current command value computing module (15) viii) according to the required controlled target of DFIG under the unbalanced source voltage condition _Rdq+ ^{+ *}, I _Rdq- ^-*, this current instruction value is converted to the rotor current command value I that just changes with in the leg speed rotating coordinate system through rotating coordinate transformation module (22) _Rdq ^{+ *}, and with just change with the rotor current feedback signal I in the leg speed rotating coordinate system _Rdq ⁺Relatively, obtain error signal Δ I _Rdq ⁺

(ix) rotor current error signal Δ I _Rdq ⁺Do ratio-integration-resonance adjusting through just changeing, regulate the back output signal U with the ratio-integration in the leg speed rotating coordinate system-resonant controller (21) _Rdq ^{+ *}Process feedback compensation decoupling zero module (20) is finished and is just changeed with cross decoupling between friendship-d-axis and dynamic feedback compensation in the leg speed rotating coordinate system, obtains the rotor voltage reference value V that just changes with in the leg speed rotating coordinate system _Rdq ^{+ *}

(x) just changeing with the rotor voltage reference value V in the leg speed rotating coordinate system _Rdq ^{+ *}By rotating coordinate transformation module (17), obtain the required rotor coordinate system rotor voltage reference signal V of space vector pulse width modulation module (19) modulation _{R α β} ^R*, this signal obtains the switching signal S of rotor-side converter (1) power device of control DFIG operation through space vector pulse width modulation module (19) modulation back _a, S _b, S _c

2. AC excitation double-fed asynchronous wind power generator rotor current non-delay control method according to claim 1, it is characterized in that (said controlled target is step viii): or keep that the output of DFIG stator has, reactive power is constant, or keep the DFIG electromagnetic torque constant, or keep the stator current balance, or the rotor current balance etc.

3. AC excitation double-fed asynchronous wind power generator rotor current non-delay control method according to claim 1, it is characterized in that just changeing with the ratio-integration in the leg speed rotating coordinate system-resonant controller (21), it comprises that it is ω that a proportional component, integral element and one are just changeing with angular frequency in the leg speed rotating coordinate system _p=2 ω _sResonator, wherein can to realize aligning commentaries on classics be 2 ω with angular frequency in the leg speed rotating coordinate system to the angular frequency resonator _sThe unlimited gain-adjusted of negative phase-sequence rotor current composition.

Images