CN101977006B - Method for controlling double-fed wind driven generator in power grid faults - Google Patents

Abstract

The invention belongs to the field of controlling a wind driven generator power conversion device and relates to a method for controlling a double-fed wind driven generator in power grid faults. The method comprises the following steps of: calculating a rotation angular velocity, calculating a stator voltage, a stator current and a rotor current under two-phase static coordinates, calculating a stator magnetic flux linkage and calculating d, q shaft stators voltage and stators current under synchronous rotational coordinates, calculating a slip-frequency angle and a slip-frequency angular velocity, calculating d, q shaft stators current under rotational coordinates, calculating a stator reactive power, calculating a rotor decoupling compensatory voltage, acquiring the actual values of a double frequency component and a triple frequency component of the rotor current after guiding the d, q shaft rotors current under rotational coordinates to flow by two band-pass filters and advanced delaying rings, acquiring the compensatory items of the double frequency component and the triple frequency component by two PI controllers after subtracting the actual values from the preset values of the double frequency component and the triple frequency component, summing the two compensatory items, acquiring a preset value of the rotor q shaft current under rotational coordinates and the reference values of d, q shaft rotors voltages under rotational coordinates by calculating with the PI controller after subtracting a preset value of the rotate speed from the actual value of the rotation angular velocity, calculating a rotor voltage under the two-phase static coordinates, and generating a switching signal for controlling a power device. The invention can efficiently prevent DFIG rotor current oscillation caused by the power grid fault, realize the on-line running of the wind driven generator and promote the running performance of the DFIG in power grid faults.

Description

The control method of double-fed wind power generator under the electric network fault situation

Technical field

The present invention relates to the control method of double-fed wind power generator under a kind of electric network fault (DFIG) rotor side inverter, belong to wind-driven generator control field.

Background technology

Owing to have the energy conversion efficiency height, advantages such as meritorious and reactive power independent regulation become the mainstream model on world's wind-power market based on the speed change wind-powered electricity generation unit of double fed induction generators (DFIG).The DFIG stator side directly links to each other with electrical network, and is very responsive to electric network fault.Electric network fault can cause the generator unit stator voltage jump, and stator current produces vibration, and generator unit stator is meritorious simultaneously also oscillatory occurences can occur with reactive power and electromagnetic torque.In addition, because the close coupling between rotor and the stator, the stator voltage of sudden change can cause the rotor current fluctuation, has influence on the running status of double feedback electric engine.When electric network fault acquires a certain degree, be the security of operation of protection converter plant, the wind-powered electricity generation unit off-the-line in the electrical network of will having no alternative but to comply.The large-scale wind power unit will further worsen electrical network from grid disconnection, the stable operation of electrical network caused have a strong impact on.To this, the power grid operation merchant requires the wind-powered electricity generation unit when line voltage falls fault, and wind-driven generator can not break away from electrical network within the specific limits, and to electrical network meritorious and idle support is provided.For example, National Grid requirement wind energy turbine set in voltage range shown in Figure 1 can be incorporated into the power networks.The voltage range indication is a wind energy turbine set tie point voltage among the figure because there are electrical isolation in generator and tie point, during electric network fault generator terminal voltage fall degree can be less than tie point electric voltage dropping degree.

The home and abroad mainly is to have adopted the rotor short-circuit resist technology to the control method of DFIG rotor-side under the electric network fault at present.This method is when electric network fault, though protected exciter converter and rotor winding, generator operation need absorb a large amount of reactive powers from electrical network in the induction motor mode at this moment, and this will further worsen electrical network; The second, the switching operation of protective circuit can produce transient state to system and impact; In addition, add new protective device and improved system cost.Have the scholar to introduce novel topological structure, this scheme control is complicated, and because the generator off-grid operation when the transmission system fault of this scheme, therefore normal operation does not have positive support effect to power system restoration; Equally, this scheme need increase the cost of system.

Adopt improved excitation control algolithm through can remedy the influence that operation is caused to double feedback electric engine of line voltage fault to a certain extent to being controlled at of rotor-side.Its advantage is to need not to improve system cost, and when electrical network falls, can meritorious idle support be provided to electrical network.Therefore, be necessary to design the control method of DFIG rotor current under a kind of electric network fault.

Summary of the invention

The objective of the invention is to solve the problem that exists in the prior art; DFIG rotor current control method under a kind of electric network fault is provided; This method need not added the additional hardware device; Can effectively suppress the DFIG rotor current vibration that electric network fault causes, realize being incorporated into the power networks of double-fed wind power generator, improve the runnability of DFIG under electric network fault.

To achieve these goals, the present invention takes following technical scheme:

The control method of double-fed wind power generator comprises the following steps: under a kind of electric network fault situation

(1) detect threephase stator voltage, the threephase stator electric current, three-phase rotor current and rotor position angle also calculate angular velocity of rotation;

(2) detected threephase stator voltage, threephase stator electric current and three-phase rotor current are obtained two stator voltage, stator current and rotor currents under the rest frame mutually through 3/2 conversion module;

(3) with the stator voltage signal under the stator two phase rest frames through software phase-lock loop; Obtain stator magnetic linkage and stator magnetic linkage position angle; And stator voltage and stator current carried out the Park conversion with the stator magnetic linkage position angle, obtain d under the synchronously rotating reference frame, q axle stator voltage and stator current; The rotor position angle that obtains according to step (1) calculates the slippage angle, and slippage angle differential is obtained slippage angular speed; Rotor current according under the two phase rest frames that calculate in the step (2) carries out the Park conversion with the slippage angle, obtains d under the rotational coordinates, q axle rotor current;

(4) calculate the stator reactive power according to the stator voltage under two cordic phase rotators, stator current; Calculate rotor decoupling compensation voltage according to the rotor current under stator magnetic linkage, slippage angular speed and the rotational coordinates; With a frequency multiplication component and the two frequency multiplication component actual values through obtaining rotor current after two band pass filters and the lead-lag link respectively of d, q axle rotor current under the rotational coordinates; This actual value is done difference and passed through two PI controllers respectively with a frequency multiplication component and two frequency multiplication component set-points respectively; Calculate a frequency multiplication component compensation term and two frequency multiplication component compensation term, with two compensation term summations;

The difference of the actual value of the stator reactive power that (5) set-point and the step (4) of stator reactive power is obtained through the PI controller after, calculate the set-point of rotating coordinate system lower rotor part d shaft current; The difference of the angular velocity of rotation actual value that rotary speed setting value and step (1) are calculated through the PI controller after, calculate the set-point of rotating coordinate system lower rotor part q shaft current;

(6) d, q axle rotor current under the rotating coordinate system that two set-points of d, q axle rotor current under the rotating coordinate system that calculates in the step (5) is calculated with step (3) respectively subtract each other, and calculate the reference value of d under the rotating coordinate system, q axle rotor voltage then through the PI controller;

(7) with d, q axle rotor voltage reference value under the rotating coordinate system respectively with separately rotor decoupling compensation voltage and two compensation term and addition, be that angle of transformation carries out anti-Park conversion with the slippage angle, obtain the rotor voltage under the rotor two phase rest frames; This rotor voltage signal produces the switching signal of power controlling device through after the space vector pulse width modulation.

As further execution mode, two band pass filter angular frequency described in the step (4) _oBe set to synchronous angular velocity ω respectively _sWith two frequency multiplication angular speed, 2 ω _s

Control method of the present invention is under the situation of not changing hardware configuration; Only add a frequency multiplication component and the two frequency multiplication components that the voltage compensation controlling unit comes compensation network instant of failure generator amature to produce respectively in two voltage inter-loops of the vector control through, reactive power decoupling zero meritorious in tradition; Suppress the rotor overcurrent that the line voltage fault is brought, be incorporated into the power networks under the stable control of realization double-fed wind power generator and the fault.Simultaneously, because rotor current obtains fine inhibition, stator current, the frequency multiplication component that stator is meritorious, reactive power and electromagnetic torque produce when the electrical network symmetry is fallen fault is also improved accordingly.

Description of drawings

Fig. 1 is the voltage range requirement of National Grid wind farm grid-connected operation during to electric network fault.

Fig. 2 is a double-fed wind power generator rotor Current Control schematic diagram under the electric network fault.

Fig. 3 is the stator voltage 50% single-phase Current Control design sketch that adopts the conventional vector control method under the fault that falls, and (a) is the stator three-phase voltage U among the figure _Sabc(KA); (b) be the rotor three-phase electric current I _Rabc(KA); (c) be stator three-phase current I _Sabc(KA); (d) be motor speed n (r/min); (e) be electromagnetic torque T _e(KNm); (f) be stator active power P _s(MW); (g) be the stator reactive power Q _s(MVar).

Fig. 4 suppresses design sketch for the stator voltage 50% single-phase electric current that adopts control method of the present invention under the fault that falls, and (a) is the stator three-phase voltage U among the figure _Sabc(KA); (b) be the rotor three-phase electric current I _Rabc(KA); (c) be stator three-phase current I _Sabc(KA); (d) be motor speed n (r/min); (e) be electromagnetic torque T _e(KNm); (f) be stator active power P _s(MW); (g) be the stator reactive power Q _s(MVar).

Fig. 5 relatively falls the electric current that adopts the conventional vector control method under the fault for 50% liang of stator voltage and suppresses design sketch, and (a) is the stator three-phase voltage U among the figure _Sabc(KA); (b) be the rotor three-phase electric current I _Rabc(KA); (c) be stator three-phase current I _Sabc(KA); (d) be motor speed n (r/min); (e) be electromagnetic torque T _e(KNm); (f) be stator active power P _s(MW); (g) be the stator reactive power Q _s(MVar).

Fig. 6 relatively falls the electric current that adopts control method of the present invention under the fault for 50% liang of stator voltage and suppresses design sketch, and (a) is the stator three-phase voltage U among the figure _Sabc(KA); (b) be the rotor three-phase electric current I _Rabc(KA); (c) be stator three-phase current I _Sabc(KA); (d) be motor speed n (r/min); (e) be electromagnetic torque T _e(KNm); (f) be stator active power P _s(MW); (g) be the stator reactive power Q _s(MVar).

Fig. 7 is the stator voltage 80% 3 symmetrical design sketch that adopts the conventional vector control method under the fault that falls, and (a) is the stator three-phase voltage U among the figure _Sabc(KA); (b) be the rotor three-phase electric current I _Rabc(KA); (c) be stator three-phase current I _Sabc(KA); (d) be motor speed n (r/min); (e) be electromagnetic torque T _e(KNm); (f) be stator active power P _s(MW); (g) be the stator reactive power Q _s(MVar).

Fig. 8 is the stator voltage 80% 3 symmetrical design sketch that adopts control method of the present invention under the fault that falls, and (a) is the stator three-phase voltage U among the figure _Sabc(KA); (b) be the rotor three-phase electric current I _Rabc(KA); (c) be stator three-phase current I _Sabc(KA); (d) be motor speed n (r/min); (e) be electromagnetic torque T _e(KNm); (f) be stator active power P _s(MW); (g) be the stator reactive power Q _s(MVar).

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is further specified.

Electric network fault generally is divided into symmetric fault and unbalanced fault, and symmetric fault generally is to be caused by electrical network three relative ground circuits, and unbalanced fault is divided into single-phase shorted to earth fault, two relative ground circuit fault and phase faults.Falling of the generator unit stator voltage that electric network fault can cause, the variation of stator voltage will cause that the generator unit stator magnetic linkage changes.Generator stator and rotor voltage equation can be expressed as the space vector form under the normal condition:

$\left\{\begin{array}{c}{u}_s^s=R_s{i}_s^s+\frac{d{\mathrm{\ψ}}_s^s}{\mathrm{dt}}\\ u_r^r=R_r{i}_r^r+\frac{d{\mathrm{\ψ}}_r^r}{\mathrm{dt}}\end{array}\right.---\left(1\right)$

In the formula: u, i, ψ, R represent voltage under the rest frame, electric current, magnetic linkage and resistance respectively.Subscript " s " and " r " represent stator and rotor reference axis system respectively, and subscript " s " and " r " represent stator and rotor variable respectively.

When electric network fault took place, stator voltage moment was fallen, and supposes to ignore stator resistance, can find out that by formula (1) stator magnetic linkage will and then change.Yet, can know that according to superconductor closed-loop path magnetic linkage conservation principle and Lenz's law though sudden change has taken place stator voltage, instant of failure generator unit stator magnetic linkage will keep invariable.Be to produce transient DC component and negative sequence component (unbalanced fault) in the stator magnetic linkage to keep electric voltage dropping moment generator unit stator magnetic linkage constant.If consider the influence of stator resistance, this DC component and negative sequence component can be decayed in time.The magnetic linkage DC component that symmetric fault produced can be expressed as a frequency multiplication component under synchronous rotating frame; The magnetic linkage negative sequence component that unbalanced fault produced can be expressed as two frequency multiplication components under synchronous rotating frame, stator magnetic linkage one frequency multiplication and two frequency multiplication components can cause the rotor current fluctuation.

Suppose that in fault taking place moment only considers electromagnetic transient, and disregard mechanical transient process, promptly generator keeps rotating speed constant during transient process.Because when fault took place, also with rotating speed rotation before the fault, the relative velocity of stator magnetic linkage DC component and rotor was a motor speed to generator amature, the relative velocity of stator magnetic linkage negative sequence component and rotor is a motor speed and with the leg speed sum.Stator magnetic linkage DC component and negative sequence component can exert an influence to rotor flux.According to closed-loop path magnetic linkage conservation principle; In order to keep the rotor flux conservation; In the rotor loop respectively the frequency of occurrences be motor speed and motor speed and with two current components of leg speed sum (unbalanced fault), these two alternating current components will produce two corresponding magnetic linkages respectively and offset the influence of stator magnetic linkage to rotor.Rotor produced the main cause of big electric current when the alternating current that rotor is inducted promptly was the fault generation.According to formula (1), rotor flux kept constant when fault took place, and rotor voltage will produce speed-frequency and motor speed respectively and with two current components of leg speed sum (unbalanced fault) with electric current.The frequency that rotor is inducted is rotor speed and motor speed and with two electric currents, magnetic linkage and component of voltages of leg speed sum (unbalanced fault); Be respectively a DC component and a negative sequence component (unbalanced fault) through coordinate transform to the stator rest frame, this is appreciated that and is stator DC component and the negative sequence component inverse process to the rotor influence.

The analysis of the inner transient state electromagnetic relationship of wind-driven generator can be known during according to above electric network fault; If suppress the induced current of rotor through compensation to rotor-exciting voltage; Can offset of the harmful effect of stator magnetic linkage transient DC component, double-fed generator can be fallen at the line voltage three-phase guarantee being incorporated into the power networks of generator when fault takes place the generator amature side.

Fig. 2 is a double-fed wind power generator rotor Current Control schematic diagram under the electric network fault.Its control method specifically comprises the steps:

(1) adopt voltage sensor and current sensor to detect threephase stator voltage V respectively _Sabc, the threephase stator electric current I _Sabc, three-phase rotor current I _Rabc, adopt encoder detection rotor angular position theta _rAnd calculating angular velocity of rotation ω _r

(2) with the detected threephase stator voltage of step (1) V _Sabc, the threephase stator electric current I _SabcWith three-phase rotor current I _RabcObtain the stator voltage V under the two phase rest frames through 3/2 conversion module _{S α β}, stator current I _{S α β}With rotor current I _{R α β}

(3) with the stator voltage signal V under the stator two phase rest frames _{S α β}Through software phase-lock loop, obtain stator magnetic linkage ψ _sAnd stator magnetic linkage angular position theta _sStator voltage V _{S α β}With stator current I _{S α β}With the stator magnetic linkage angular position theta _sCarry out the Park conversion, obtain the stator voltage u under the synchronously rotating reference frame _Sd, u _SqWith stator current i _Sd, i _SqThe rotor position angle θ that obtains according to step (1) _rCalculate slippage angle θ _s-θ _r, slippage angle differential obtains the slippage angular velocity omega _SlAccording to the rotor current I under the two phase rest frames that calculate in the step (2) _{R α β}With slippage angle θ _s-θ _rCarry out the Park conversion, obtain the rotor current i under the rotational coordinates _Rd, i _Rq

(4) the stator voltage u under two cordic phase rotators that calculate through step (3) _Sd, u _Sq, stator current i _Sd, i _SqWith rotor current i _Rd, i _RqCalculate stator active power P _s, reactive power Q _sWith electromagnetic torque T _eWith the stator magnetic linkage ψ that obtains in the step (3) _s, the slippage angular velocity omega _SlAnd rotor current i _Rd, i _RqCalculate rotor decoupling compensation voltage u _Rd, u _RqWith a frequency multiplication component and the two frequency multiplication component actual values through obtaining rotor current after two band pass filters and the lead-lag link respectively of d, q axle rotor current under the rotational coordinates; This actual value is done difference and passed through two PI controllers respectively with a frequency multiplication component and two frequency multiplication component set-points respectively; Calculate a frequency multiplication component compensation term and two frequency multiplication component compensation term, and with two compensation rates sue for peace u _Crd, u _Crq

(5) with the set-point Q of stator reactive power _s ^*The actual value Q of the stator reactive power that calculates with step (4) _sDifference through behind the PI controller, calculate the set-point i of rotating coordinate system lower rotor part d shaft current _Rd ^*With rotary speed setting value ω _r ^*The angular velocity of rotation actual value ω that calculates with step (1) _rDifference through behind the PI controller, calculate the set-point i of rotating coordinate system lower rotor part q shaft current _Rq ^*

(6) with the rotating coordinate system lower rotor part d that calculates in the step (5), the set-point i of q shaft current _Rd ^*And i _Rq ^*D, q axle rotor current i under the rotating coordinate system that is calculated with step (3) respectively _RdAnd i _RqSubtract each other, calculate the reference value u of rotating coordinate system lower rotor part d, q shaft voltage then through the PI controller _Rd ^*And u _Rq ^*

(7) the rotor voltage reference value u under the rotating coordinate system that calculates of step (6) _Rd ^*, u _Rq ^*Respectively with step (4) in the rotor decoupling compensation voltage u separately that calculates _Rd', u _Rq' and compensation term and u _Crd, u _CrqAddition is with detected slippage angle θ in the step (3) _s-θ _rFor angle of transformation carries out anti-Park conversion, obtain the rotor voltage V under the rotor two phase rest frames _{R α β}This rotor voltage signal produces the switching signal of power controlling device through after the space vector pulse width modulation.

Key points in design of the present invention promptly is in the control method of double-fed wind power generator under above-mentioned electric network fault, through the reason of analysis overcurrent generation and the characteristics of overcurrent, utilizes the voltage compensation ring that rotor inductive currents is suppressed.Realized being incorporated into the power networks of double-fed wind power generator under the electric network fault.

The control method principle analysis of double-fed wind power generator is following under the said electric network fault:

At first meritorious, the reactive power decoupling zero vector control of traditional stator flux linkage orientation are analyzed.Double feedback electric engine Derivation of Mathematical Model under the stator magnetic linkage oriented rotating coordinate system is following:

When stator and rotor-side power taking motivation convention, the fundamental equation of double-fed generator under synchronous rotating frame is:

$\left\{\begin{array}{c}{u}_{\mathrm{sd}}=R_s{i}_{\mathrm{sd}}+\frac{{\mathrm{d\ψ}}_{\mathrm{sd}}}{\mathrm{dt}}-{\mathrm{\ω}}_s{\mathrm{\ψ}}_{\mathrm{sq}}\\ u_{\mathrm{sq}}=R_s{i}_{\mathrm{sq}}\frac{{\mathrm{d\ψ}}_{\mathrm{sq}}}{\mathrm{dt}}+{\mathrm{\ω}}_s{\mathrm{\ψ}}_{\mathrm{sd}}\\ u_{\mathrm{rd}}=R_r{i}_{\mathrm{rd}}+\frac{{\mathrm{d\ψ}}_{\mathrm{rd}}}{\mathrm{dt}}-{\mathrm{\ω}}_{\mathrm{sl}}{\mathrm{\ψ}}_{\mathrm{rq}}\\ u_{\mathrm{rq}}=R_r{i}_{\mathrm{rq}}+\frac{{\mathrm{d\ψ}}_{\mathrm{rq}}}{\mathrm{dt}}+{\mathrm{\ω}}_{\mathrm{sl}}{\mathrm{\ψ}}_{\mathrm{rd}}\end{array}\right.---\left(2\right)$

U wherein _Sd, u _SqBe respectively d, the q axle component of stator voltage, u _Rd, u _RqBe respectively d, the q axle component of rotor voltage, i _Sd, i _SqBe respectively d, the q axle component of stator current, i _Rd, i _RqBe respectively d, the q axle component of rotor current, ψ _Sd, ψ _SqBe respectively d, the q axle component of stator magnetic linkage, ψ _Rd, ψ _RqBe respectively d, the q axle component of rotor flux; R _s, R _rBe respectively stator and rotor resistance parameters; ω _sBe synchronous angular velocity of rotation, ω _rBe rotor angular velocity of rotation, ω _SlBe slip angular velocity, ω _Sl=(ω _s-ω _r)

The magnetic linkage equation:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{sd}}=L_s{i}_{\mathrm{sd}}+L_m{i}_{\mathrm{rd}}\\ {\mathrm{\ψ}}_{\mathrm{sq}}=L_s{i}_{\mathrm{sq}}+L_m{i}_{\mathrm{rq}}\\ {\mathrm{\ψ}}_{\mathrm{rd}}=L_m{i}_{\mathrm{sd}}+L_r{i}_{\mathrm{rd}}\\ {\mathrm{\ψ}}_{\mathrm{rq}}=L_m{i}_{\mathrm{sq}}+L_r{i}_{\mathrm{rq}}\end{array}\right.---\left(3\right)$

L in the formula _sBe stator self-induction, L _rBe rotor self-induction, L _mBe stator and rotor mutual inductance.

Be oriented in the d axle of synchronous rotating frame on the stator magnetic linkage, even ω _Sd=ω _s, ψ _Sq=0.Can derive by preceding two formulas in the formula (3):

$\left\{\begin{array}{c}{i}_{\mathrm{sd}}=\frac{{\mathrm{\ψ}}_s}{L_s}-\frac{L_m}{L_s}{i}_{\mathrm{rd}}\\ i_{\mathrm{sq}}=-\frac{L_m}{L_s}{i}_{\mathrm{rq}}\end{array}\right.---\left(\text{4}\right)$

Back two formulas in formula (4) and the formula (2) and the back two formula simultaneous in the formula (3) can be got:

$\left\{\begin{array}{c}{u}_{\mathrm{rd}}=R_r{i}_{\mathrm{rd}}+{\mathrm{\σL}}_r\frac{{\mathrm{di}}_{\mathrm{rd}}}{\mathrm{dt}}-{\mathrm{\ω}}_{\mathrm{sl}}\mathrm{\σ}{L}_r{i}_{\mathrm{rq}}\\ u_{\mathrm{rq}}=R_r{i}_{\mathrm{rq}}+\mathrm{\σ}{L}_r\frac{{\mathrm{di}}_{\mathrm{rq}}}{\mathrm{dt}}+{\mathrm{\ω}}_{\mathrm{sl}}(\mathrm{\σ}{L}_r{i}_{\mathrm{rd}}+\frac{L_m}{L_s}{\mathrm{\ψ}}_s)\end{array}\right.---\left(5\right)$

Wherein, $\mathrm{\&sigma;}=1-{\mathrm{<figure-callout\; id="2"\; label="L\; m"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">L</figure-callout>}}_m^{}/\left(L_r{L}_s\right)$

On the basis of traditional stator flux linkage orientation vector control, a frequency multiplication weight expression of derivation rotor current, process is derived as follows:

The analysis of transient state electromagnetic relationship can be known during by above electric network fault, and rotor voltage and electric current can be expressed as when fault took place:

$\left\{\begin{array}{c}{u}_{\mathrm{rd}}=u_{\mathrm{<figure-callout\; id="0"\; label="rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rd</figure-callout>}0}+u_{\mathrm{<figure-callout\; id="1"\; label="rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rd</figure-callout>}1}+u_{\mathrm{rd}2}\\ u_{\mathrm{rq}}=u_{\mathrm{<figure-callout\; id="0"\; label="rq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rq</figure-callout>}0}+u_{\mathrm{<figure-callout\; id="1"\; label="rq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rq</figure-callout>}1}+u_{\mathrm{rq}2}\\ i_{\mathrm{rd}}=i_{\mathrm{<figure-callout\; id="0"\; label="rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rd</figure-callout>}0}+{\mathrm{<figure-callout\; id="1"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}+i_{\mathrm{rd}2}\\ i_{\mathrm{rq}}=i_{\mathrm{<figure-callout\; id="0"\; label="rq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rq</figure-callout>}0}+{\mathrm{<figure-callout\; id="1"\; label="i\; rq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rq}}+i_{\mathrm{rq}2}\end{array}\right.---\left(6\right)$

U wherein _Rd0, u _Rq0, i _Rd0, i _Rq0Represent dq coordinate system rotor voltage and current DC component respectively, u _Rd1, u _Rq1, i _Rd1, i _Rq1Represent dq coordinate system rotor voltage and current one frequency multiplication component respectively, u _Rd2, u _Rq2, i _Rd2, i _Rq2Represent dq coordinate system rotor voltage and current two frequency multiplication components respectively.

If ψ _Sd=ψ _s, ψ _Sq=0, stator magnetic linkage can be expressed as when fault took place:

$\left\{\begin{array}{c}{\mathrm{\&psi;}}_s={\mathrm{\&psi;}}_{\mathrm{<figure-callout\; id="0"\; label="s"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">s</figure-callout>}0}+{\mathrm{\&psi;}}_{s1}+{\mathrm{\&psi;}}_{s2}\\ {\mathrm{\&psi;}}_{\mathrm{sq}}=0\end{array}\right.---\left(7\right)$

ψ wherein _S0Expression dq coordinate system rotor magnetic linkage DC component, ψ _S1Expression dq coordinate system rotor magnetic linkage one frequency multiplication component, ψ _S2Expression dq coordinate system rotor magnetic linkage two frequency multiplication components.

Can get by formula (5):

$\left\{\begin{array}{c}\frac{{\mathrm{di}}_{\mathrm{rd}}}{\mathrm{dt}}=-\frac{R_r{i}_{\mathrm{rd}}}{{\mathrm{\&sigma;L}}_r}+\frac{u_{\mathrm{rd}}}{\mathrm{\&sigma;}{L}_r}+{\mathrm{\&omega;}}_{\mathrm{sl}}{i}_{\mathrm{rq}}\\ \frac{{\mathrm{di}}_{\mathrm{rq}}}{\mathrm{dt}}=\frac{R_r{i}_{\mathrm{rq}}}{\mathrm{\&sigma;}{L}_r}+\frac{u_{\mathrm{rq}}}{{\mathrm{\&sigma;L}}_r}-{\mathrm{\&omega;}}_{\mathrm{sl}}(i_{\mathrm{rd}}+\frac{L_m}{L_s{L}_r\mathrm{\&sigma;}}{\mathrm{\&psi;}}_s)\end{array}\right.---\left(8\right)$

Simultaneous formula (6), (7) and (8), and a frequency multiplication component of system and two frequency multiplication components are proposed respectively:

$\left\{\begin{array}{c}\frac{{\mathrm{di}}_{\mathrm{<figure-callout\; id="1"\; label="rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rd</figure-callout>}1}}{\mathrm{dt}}=-\frac{R_{\mathrm{<figure-callout\; id="1"\; label="r\; i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">r</figure-callout>}}{i}_{\mathrm{rd}}{1}_{}}{\mathrm{\&sigma;}{L}_r}+\frac{{\mathrm{<figure-callout\; id="1"\; label="u\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{rd}}}{\mathrm{\&sigma;}{L}_r}+{\mathrm{\&omega;}}_{\mathrm{sl}}{i}_{\mathrm{rq}1}\\ \frac{{\mathrm{di}}_{\mathrm{rq}1}}{\mathrm{dt}}=-\frac{R_r{i}_{\mathrm{rq}1}}{\mathrm{\&sigma;}{L}_r}+\frac{{\mathrm{<figure-callout\; id="1"\; label="u\; rq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{rq}}}{\mathrm{\&sigma;}{L}_r}-{\mathrm{\&omega;}}_{\mathrm{sl}}({\mathrm{<figure-callout\; id="1"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}+\frac{L_m{\mathrm{\&psi;}}_{s1}}{L_s{L}_r\mathrm{\&sigma;}})\\ \frac{{\mathrm{di}}_{\mathrm{<figure-callout\; id="2"\; label="rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">rd</figure-callout>}2}}{\mathrm{dt}}=-\frac{R_{\mathrm{<figure-callout\; id="2"\; label="r\; i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">r</figure-callout>}}{i}_{\mathrm{rd}}{2}_{}}{\mathrm{\&sigma;}{L}_r}+\frac{{\mathrm{<figure-callout\; id="2"\; label="u\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{rd}}}{\mathrm{\&sigma;}{L}_r}+{\mathrm{\&omega;}}_{\mathrm{sl}}{i}_{\mathrm{rq}2}\\ \frac{{\mathrm{di}}_{\mathrm{rq}2}}{\mathrm{dt}}=-\frac{R_r{i}_{\mathrm{rq}2}}{\mathrm{\&sigma;}{L}_r}+\frac{{\mathrm{<figure-callout\; id="2"\; label="u\; rq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{rq}}}{\mathrm{\&sigma;}{L}_r}-{\mathrm{\&omega;}}_{\mathrm{sl}}({\mathrm{<figure-callout\; id="2"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}+\frac{L_m{\mathrm{\&psi;}}_{s2}}{L_s{L}_r\mathrm{\&sigma;}})\end{array}\right.---\left(9\right)$

Can know that by formula (9) a frequency multiplication component of stator and rotor electric current and two frequency multiplication components can be controlled by corresponding d, q shaft voltage.

More than analyzed a frequency multiplication weight expression of electric network fault lower rotor part electric current, the design voltage compensation tache satisfies the requirement of being incorporated into the power networks on this basis below.Derivation is following:

According to based on a stator magnetic linkage oriented DFIG control strategy and a frequency multiplication weight expression of deriving, can set up as shown in the figure 2 DFIG control system, system is made up of master control system and voltage compensation link two parts.

The master control system design

Can design by formula (5) based on the stator magnetic linkage oriented dq of DFIG system shaft current.

$\left\{\begin{array}{c}{u}_{\mathrm{rd}}=R_r{i}_{\mathrm{rd}}+\mathrm{\&sigma;}{L}_r{V}_{\mathrm{rd}}-{\mathrm{\&omega;}}_{\mathrm{sl}}\mathrm{\&sigma;}{L}_r{i}_{\mathrm{rq}}\\ u_{\mathrm{rq}}=R_r{i}_{\mathrm{rq}}+\mathrm{\&sigma;}{L}_r{V}_{\mathrm{rq}}+{\mathrm{\&omega;}}_{\mathrm{sl}}({\mathrm{\&sigma;L}}_r{i}_{\mathrm{rd}}+\frac{L_m}{L_s}{\mathrm{\&psi;}}_{\mathrm{sd}})\end{array}\right.---\left(10\right)$

V _Rd, V _RqCan regulate by following formula respectively:

$\left\{\begin{array}{c}{V}_{\mathrm{rd}}={\mathrm{di}}_{\mathrm{rd}}/\mathrm{dt}=k_{p0}(i_{\mathrm{rd}}^{*}-i_{\mathrm{rd}})+{\mathrm{<figure-callout\; id="0"\; label="k\; i"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_i\&Integral;(i_{\mathrm{rd}}^{*}-i_{\mathrm{rd}})\mathrm{dt}\\ V_{\mathrm{rq}}={\mathrm{di}}_{\mathrm{rq}}/\mathrm{dt}=k_{p0}(i_{\mathrm{rq}}^{*}-i_{\mathrm{rq}})+{\mathrm{<figure-callout\; id="0"\; label="k\; i"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_i\&Integral;(i_{\mathrm{rq}}^{*}-i_{\mathrm{rq}})\mathrm{dt}\end{array}\right.---\left(11\right)$

K wherein _P0, k _I0Be respectively ratio, the integral parameter of electric current loop.

The compensation tache design

Rotor current one frequency multiplication component and two frequency multiplication component compensation taches can design by formula (9).

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="u\; crd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{crd}}=R_r{\mathrm{<figure-callout\; id="1"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}+\mathrm{\&sigma;}{L}_r{V}_{\mathrm{crd}1}-{\mathrm{\&omega;}}_{\mathrm{sl}}\mathrm{\&sigma;}{L}_r{i}_{\mathrm{rq}1}\\ {\mathrm{<figure-callout\; id="1"\; label="u\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{crq}}=R_r{i}_{\mathrm{rq}1}+\mathrm{\&sigma;}{L}_{\mathrm{<figure-callout\; id="1"\; label="r\; V\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">r</figure-callout>}}{V}_{\mathrm{crq}}{1}_{}+{\mathrm{\&omega;}}_{\mathrm{sl}}{\mathrm{\&xi;}}_1\\ {\mathrm{<figure-callout\; id="2"\; label="u\; crd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{crd}}=R_r{\mathrm{<figure-callout\; id="2"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}+\mathrm{\&sigma;}{L}_r{V}_{\mathrm{crd}2}\text{-}{\mathrm{\&omega;}}_{\mathrm{sl}}\mathrm{\&sigma;}{L}_r{i}_{\mathrm{rq}2}\\ {\mathrm{<figure-callout\; id="2"\; label="u\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{crq}}=R_r{i}_{\mathrm{rq}2}+\mathrm{\&sigma;}{L}_{\mathrm{<figure-callout\; id="2"\; label="r\; V\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">r</figure-callout>}}{V}_{\mathrm{crq}}{2}_{}\text{+}{\mathrm{\&omega;}}_{\mathrm{sl}}{\mathrm{\&xi;}}_2\\ u_{\mathrm{crd}}={\mathrm{<figure-callout\; id="1"\; label="u\; crd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{crd}}+u_{\mathrm{crd}2}\\ u_{\mathrm{crq}}={\mathrm{<figure-callout\; id="1"\; label="u\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{crq}}{+u}_{\mathrm{crq}2}\end{array}\right.---\left(12\right)$

U wherein _Crd1, u _Crq1And u _Crd2, u _Crq2Be respectively d, the q axle component of rotor current one frequency multiplication component and two frequency multiplication component bucking voltages, u _Crd, u _CrqBe respectively d, each component bucking voltage sum of q axle.ξ ₁＝(σL _ri _rd1+ψ _s1L _m/L _s)，ξ ₂＝(σL _ri _rd2+ψ _s2L _m/L _s)。

V _Crd1, V _Crq1And V _Crd2, V _Crq2Can regulate by following formula respectively:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="V\; crd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{crd}}=k_{p1}({\mathrm{<figure-callout\; id="1"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}^1-i_{\mathrm{rd}1})+{\mathrm{<figure-callout\; id="1"\; label="k\; i"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_i\&Integral;({\mathrm{<figure-callout\; id="1"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}^1-i_{\mathrm{rd}1})\mathrm{<figure-callout\; id="1"\; label="dt\; V\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">dt</figure-callout>}& \\ V_{\mathrm{crq}}{1}_{}=k_{p1}(i_{\mathrm{rq}1}^{*}-i_{\mathrm{rq}1})+{\mathrm{<figure-callout\; id="1"\; label="k\; i"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_i\&Integral;(i_{\mathrm{rq}1}^{*}-i_{\mathrm{rq}1})\mathrm{<figure-callout\; id="2"\; label="dt\; V\; crd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">dt</figure-callout>}& \\ V_{\mathrm{crd}}{2}_{}=k_{p2}({\mathrm{<figure-callout\; id="2"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}^2-i_{\mathrm{rd}2})+{\mathrm{<figure-callout\; id="2"\; label="k\; i"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_i\&Integral;({\mathrm{<figure-callout\; id="2"\; label="i\; rd"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">i</figure-callout>}}_{\mathrm{rd}}^2-i_{\mathrm{rd}2})\mathrm{<figure-callout\; id="2"\; label="dt\; V\; crq"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">dt</figure-callout>}& \\ V_{\mathrm{crq}}{2}_{}=k_{p2}(i_{\mathrm{rq}2}^{*}-i_{\mathrm{rq}2})+{\mathrm{<figure-callout\; id="2"\; label="k\; i"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">k</figure-callout>}}_i\&Integral;(i_{\mathrm{rq}2}^{*}-i_{\mathrm{rq}2})\mathrm{dt}\end{array}\right.---\left(13\right)$

K wherein _P1, k _I1And k _P2, k _I2Ratio, integral parameter for compensated loop.

Through type (12) and (10) can find out that various first and third a frequency multiplication component is included in the master control link, in the compensation tache design, only need to consider second and get final product.

Can know from top derivation result, can effectively suppress the influence of electric network fault the motor operation through control to rotor current.

G among Fig. 2 ₁(s) and G ₂(s) be band pass filter, be used to extract a frequency multiplication component and the two frequency multiplication components of rotor current, angular frequency _oBe set to ω respectively _o=ω _sAnd ω _o=2 ω _s, its expression formula is:

${\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">G</figure-callout>}}_{\mathrm{1,2}}\left(s\right)=\frac{({\mathrm{\&omega;}}_0/Q_f)s}{{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="HDA0000029905370000021.png,HDA0000029905370000031.png"\; state="\{\{state\}\}">s</figure-callout>}}^2+({\mathrm{\&omega;}}_0/Q_f)s+{\left({\mathrm{\&omega;}}_0\right)}^2}---\left(14\right)$

Q wherein _fBe quality factor.

G _D1(s) and G _D2(s) be delay component, its effect is the phase lag that compensation causes because of band pass filter.Its expression formula is:

$\left\{\begin{array}{c}{G}_{d1}\left(s\right)=\frac{K_{1}s+D_1}{K_{2}s+D_2}\\ G_{d2}\left(s\right)=\frac{K_{3}s+D_3}{K_{4}s+D_4}\end{array}\right.---\left(15\right)$

Be the correctness of proof theory and the validity of compensation control strategy; Suppose that electric network fault makes under the condition that the generator unit stator set end voltage falls; The method that adopts the present invention to propose is the control of 1.5MW DFIG system implementation to a rated power, and rotor current has been converted stator side.Be located in the control procedure and keep wind-driven generator to be incorporated into the power networks all the time, and frequency converter operate as normal all the time.

Electric network fault lower rotor part voltage control strategy to traditional stator flux linkage orientation vector control strategy and proposition compares, and Fig. 3 and Fig. 4 are respectively and adopt traditional double-fed wind powered generator control method and control method of the present invention at the stator voltage 50% single-phase operation result that falls under the condition that electric network fault causes.Line voltage falls at 0.1s constantly, recovers normal constantly at 0.6s.When traditional control method of Fig. 3 takes place in the electric network electric voltage drop fault; Because the frequency multiplication component that the stator voltage variation is produced and the influence of two frequency multiplication components; The stator and rotor electric current of DFIG significantly increases and with two double-frequency oscillations, will surpass the current limit value of converter plant in the real system during electric network electric voltage drop, causes wind turbine generator will have to and grid disconnection; This both had been unfavorable for the stable operation of generator, also was unfavorable for the fault recovery and the stable operation of electrical network.Stator is meritorious, reactive power and electromagnetic torque have all produced thermal agitation, and vibration significantly meritorious, reactive power will influence stablizing of electrical network, and the thermal agitation of electromagnetic torque will cause the generator mechanical failure.Compare with traditional control method; Fig. 4 control method has effectively been eliminated a frequency multiplication component and the two frequency multiplication components of rotor current under the electric network fault; Suppressed the generation of rotor overcurrent; Simultaneously stator current, meritorious, reactive power and electromagnetic torque pulsation obviously reduce, and motor can send the recovery that lasting meritorious, reactive power are supported electrical network.The wind turbine generator of this method control satisfies the condition that is incorporated into the power networks, and has improved the operation control ability of DFIG under the electric network fault condition, has improved the dynamic quality of control system.

Fig. 5 and Fig. 6 are respectively 50% liang of stator voltage and relatively fall torque and the power control effect figure that adopts conventional vector control and the inventive method under the fault.Line voltage falls at 0.1s constantly, recovers normal constantly at 0.3s.Compare with traditional control method of Fig. 5, a frequency multiplication component and two frequency multiplication components that the control method of Fig. 6 can effectively suppress rotor current satisfy the requirement of being incorporated into the power networks.

Fig. 7 and Fig. 8 are respectively and adopt traditional double-fed wind powered generator control method and the inventive method to fall the operation result under the condition at stator voltage 80% three-phase that electric network fault causes.Line voltage falls at 0.1s constantly, recovers normal constantly at 0.3s.Find out that by Fig. 7 electric network fault takes place and the recovery moment, stator and rotor electric current generation thermal agitation produces serious overcurrent, and at this moment protective device must start the safety with the protection frequency converter.Necessary and the grid disconnection of generating set has further influenced the recovery of electric network fault.

Fig. 8 is the control design sketch of the inventive method, takes place and the recovery moment at electric network fault among the figure, and this control method has effectively suppressed a frequency multiplication component of rotor current, and the vibration of electric current is very little, does not influence the operation of wind turbine generator.When falling fault and take place, motor speed begins to rise, this be since the capacity limit of frequency converter generator when fault takes place to the control of rotating speed.As shown in Figure 1, when taking place seriously to fall, electric power operator has only 150ms to the time that blower fan keeps being incorporated into the power networks, so the rotating speed rising can be not a lot, does not influence the stable operation of system.By finding out among Fig. 8, after line voltage recovered, rotating speed was controlled very soon, satisfies the requirement that wind-driven generator is incorporated into the power networks under the electrical network catastrophe failure.

In sum; Control method of the present invention is compared with traditional stator flux linkage orientation vector control; Under electric network fault; Control system can effectively be eliminated a frequency multiplication component and two frequencys multiplication of rotor, suppresses the generation of rotor overcurrent, has strengthened the run without interruption ability of DFIG wind-powered electricity generation unit under electric network fault; Institute's control system algorithm of carrying is simple; Only need in two voltage inter-loops of conventional vector control, add the voltage compensation controlling unit respectively; Just can reach inhibition, and the rotor current that reduces makes the stator overcurrent also obtain obvious inhibition to the influence of stator magnetic linkage to the rotor overcurrent.

Claims (1)

1. the control method of double-fed wind power generator under the electric network fault situation comprises the following steps:

(1) detect threephase stator voltage, the threephase stator electric current, three-phase rotor current and rotor position angle also calculate angular velocity of rotation;

(2) detected threephase stator voltage, threephase stator electric current and three-phase rotor current are obtained two stator voltage, stator current and rotor currents under the rest frame mutually through 3/2 conversion module;

(3) with the stator voltage signal under the stator two phase rest frames through software phase-lock loop; Obtain stator magnetic linkage and stator magnetic linkage position angle; And threephase stator voltage and stator current carried out the Park conversion with the stator magnetic linkage position angle, obtain d, q axle stator voltage and stator current under the two synchronised rotational coordinatess; The rotor position angle that obtains according to step (1) calculates the slippage angle, and slippage angle differential is obtained slippage angular speed; Rotor current according under the two phase rest frames that calculate in the step (2) carries out the Park conversion with the slippage angle, obtains d under the two synchronised rotational coordinatess, q axle rotor current;

(4) calculate the stator reactive power according to the d under the two synchronised rotational coordinatess, q axle stator voltage, stator current; Calculate rotor decoupling compensation voltage according to the rotor current under stator magnetic linkage, slippage angular speed and the two synchronised rotational coordinatess; With a frequency multiplication component and the two frequency multiplication component actual values through obtaining rotor current after two band pass filters and the lead-lag link respectively of d, q axle rotor current under the two synchronised rotational coordinatess; This actual value is done difference and passed through two PI controllers respectively with a frequency multiplication component and two frequency multiplication component set-points respectively; Calculate a frequency multiplication component compensation term and two frequency multiplication component compensation term; With two compensation term summations, described two band pass filter angular frequency _OBe set to synchronous angular velocity ω respectively _SWith two frequency multiplication angular speed, 2 ω _S

The difference of the actual value of the stator reactive power that (5) set-point and the step (4) of stator reactive power is obtained through the 3rd PI controller after, calculate the set-point of d axle rotor current under the two synchronised rotating coordinate systems; The difference of the angular velocity of rotation actual value that rotary speed setting value and step (1) are calculated through the 4th PI controller after, calculate the set-point of q axle rotor current under the two synchronised rotating coordinate systems;

(6) d, q axle rotor current under the two synchronised rotating coordinate systems that two set-points of d, q axle rotor current under the two synchronised rotating coordinate systems that calculate in the step (5) calculated with step (3) respectively subtract each other, and calculate the reference value of d under the two synchronised rotating coordinate systems, q axle rotor voltage then respectively through the 5th and the 6th PI controller;

(7) with d, q axle rotor voltage reference value under the two synchronised rotating coordinate systems respectively with separately rotor decoupling compensation voltage and two compensation term and addition; With the slippage angle is that angle of transformation carries out anti-Park conversion, obtains the rotor voltage under the rotor two phase rest frames; This rotor voltage signal produces the switching signal of power controlling device through after the space vector pulse width modulation.

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