CN103259290A - Method for controlling direct voltage of doubly-fed generator grid-side converter without phase-locked loop - Google Patents

Abstract

The invention provides a method for controlling direct voltage of a doubly-fed generator grid-side converter without a phase-locked loop. The method for controlling the direct voltage of the doubly-fed generator grid-side converter without the phase-locked loop comprises the following steps: the angular speed omega of synchronous rotation of network voltage is elicited and the trigonometric function sin theta-cos theta of the angle theta used for rotation transformation is elicited; a three-phase voltage equation is elicited; the input power Pg of an active component controller and the input power Qg of a reactive component controller are elicited, wherein the input power Pg and the input power Qg are sent to a power grid by the grid-side converter and the relation between grid-side converter control voltage and direct current bus voltage is deduced; the d-axis component of the control voltage and the q-axis component of the control voltage are elicited; the d-axis control voltage and the q-axis control voltage are sent to a PWM signal generating module and a PWM signal is generated and output to an IGBT unit. The method for controlling the direct voltage of the doubly-fed generator grid-side converter without the phase-locked loop has the advantages that effective control over the direct current bus voltage can be achieved through one closed loop PI controller, the dynamic response performance of a control system is improved; manufacturing cost is low, and production efficiency and stability are greatly improved.

Description

A kind of double-fed generator net side converter direct voltage control method of no phase-locked loop

Technical field

The invention belongs to generating, power transformation or distribution field, especially relate to a kind of double-fed generator net side converter direct voltage control method of no phase-locked loop.

Background technology

In existing technology, the wind power generation development is rapid, and various technology are gradually improved.Double-fed generator is as one of critical piece of wind-powered electricity generation unit, adopts back-to-back two PWM current transformers to realize its variable speed constant frequency generator.Two PWM current transformers comprise net side converter and pusher side current transformer.The control of net side converter is related to the stable and safety of DC bus-bar voltage, the power factor that the net side converter injects electrical network.At the control of net side converter, present existing have conventional vector control technology and direct Power Control technology.The conventional vector control technology is taked line voltage orientation, virtual electrical network flux linkage orientation etc. usually, by synchronous rotation transformation, is issued to the decoupling zero control of real component and idle component at the dq rotating coordinate system.Two closed loops are adopted in the control of real component, and outer shroud is the DC bus-bar voltage ring, and interior ring is the active current ring; Single electric current loop is adopted in the control of idle component, directly is given as reactive current.The sine and the cosine sin θ _ cos θ that control the synchronous angular velocity of rotation ω of used line voltage and the θ angle that rotation transformation is used obtain by software phase-lock loop or hardware phase-locked-loop PLL.The direct Power Control technology adopts and the similar thinking of conventional vector control: take line voltage orientation, virtual electrical network flux linkage orientation etc., by synchronous rotation transformation, be issued to the decoupling zero control of real component and idle component at the dq rotating coordinate system.Two closed loops of real component are outer shroud DC bus-bar voltage ring, interior ring active power ring; The single closed loop of idle component is the reactive power ring, and the sine and the cosine sin θ _ cos θ that control the synchronous angular velocity of rotation ω of used line voltage and the θ angle that rotation transformation is used obtain by software phase-lock loop or hardware phase-locked-loop PLL.To sum up, the something in common of these two kinds of control methods is: two closed loops are all adopted in the control of real component; Single closed loop is adopted in the control of idle component; All realizing meritorious and idle decoupling zero control under the rotation dq coordinate system synchronously; The synchronous angular velocity of rotation ω of line voltage is obtained by PLL in the sine at the θ angle that rotation transformation is used and cosine sin θ _ cos θ and the decoupling zero control.Difference is: what the conventional vector control technology was controlled in fact is the electric current that exchanges between net side converter and the electrical network, and the control of direct Power Control technology is the power that exchanges between net side converter and the electrical network.

Above-mentioned said existing conventional vector control technology and direct Power Control technology have following technical problem to need to improve:

1. two closed loops are adopted in the control of real component, and outer shroud is the DC bus-bar voltage ring, and interior ring is power ring or electric current loop, needs two PI controllers, and at least 4 of controller parameters can increase difficulty and the complexity of system debug; And when given changing, two PI controllers have two dynamic adjustments processes, can influence the dynamic property of system; The unreasonable configuration of final parameter also may influence the reliability of system.

2. the control effect relies on phase-locked loop, and the dynamic characteristic of phase-locked loop may influence the dynamic characteristic of control effect.The PI controller is contained in phase-locked loop inside, the debugging of its parameter with and very big to the influence of whole system control effect.

Summary of the invention

The problem to be solved in the present invention provides a kind of Circuits System of power supply of power field, especially is suitable for the circuit arrangement of a kind of ac mains or ac distribution network.

For solving the problems of the technologies described above, the step that the present invention adopts is:

The first step,

Derivation draws the synchronous angular velocity of rotation ω of line voltage,

Derivation draws for the sine at the θ angle of rotation transformation and cosine sin θ _ cos θ,

Second step,

Topological relation according to the net side converter draws the three-phase voltage equation;

Derive the input power P that the net side converter is sent into the real component controller of electrical network by voltage equation, power equation successively _gInput power Q with the idle component controller _g,

The relation between net side converter control voltage and the DC bus-bar voltage derived be double-fed generator net side frequency converter directly control voltage be decoupling zero item and compensation term and;

The 3rd step,

The DC bus-bar voltage set-point square with the DC bus-bar voltage measured value square ask poor, obtain error amount, send into the PI controller, obtain the decoupling zero item through the PI controller, itself and compensation term addition, just the d axle component of controlled voltage;

The 4th step,

Reactive power set-point and wattless power measurement value ask poor, obtain error amount, send into the PI controller, obtain the decoupling zero item through the PI controller, itself and compensation term addition, just the q axle component of controlled voltage;

The 5th step,

D, q axle control voltage are sent into the pwm signal generation module, generate pwm signal and export to the IGBT unit.

Further, the formula of the synchronous angular velocity of rotation ω of described line voltage is:

$\mathrm{\ω}=\frac{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\β}}\left(t\right)-u_{\mathrm{\α}}(t-\mathrm{\Δt})u_{\mathrm{\β}}(t-\mathrm{\Δt})}{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)u_{\mathrm{\β}}(t-\mathrm{\Δt})}*\frac{1}{\mathrm{\Δt}}.$

Further, the sine at described θ angle for rotation transformation and the formula of cosine sin θ _ cos θ are:

$\left[\begin{array}{c}\cos \mathrm{\θ}\\ \sin \mathrm{\θ}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{\α}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\\ \frac{u_{\mathrm{\β}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\end{array}\right].$

Further, the formula of described three-phase voltage equation is:

$\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]=R_g\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+L_g\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+\left[\begin{array}{c}{u}_{\mathrm{gca}}\\ u_{\mathrm{gcb}}\\ u_{\mathrm{gcc}}\end{array}\right].$

Further, the input power P of described real component controller _gInput power Q with the idle component controller _gFormula be: $\left\{\begin{array}{c}{P}_g=\frac{3}{2}{u}_{\mathrm{gd}}{i}_{\mathrm{gd}}=\frac{3}{2}{u}_1{i}_{\mathrm{gd}}\\ Q_g=\frac{3}{2}(-u_{\mathrm{gd}}{i}_{\mathrm{gq}})=-\frac{3}{2}{u}_1{i}_{\mathrm{gq}}\end{array}\right..$

Further, the formula of described decoupling zero item is: $\left\{\begin{array}{c}{u}_{\gcd }=\frac{d}{\mathrm{dt}}\left(\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}\right)\\ u_{\mathrm{gcq}}=\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right..$

Further, the formula of described compensation term is: $\left\{\begin{array}{c}{u}_{\gcd }=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{\mathrm{gcq}}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right..$

Advantage and good effect that the present invention has are: owing to adopt the direct voltage control method that double-fed generator net side converter is controlled, need not to adopt phase-locked loop, only just can realize the quick of DC bus-bar voltage and effectively control have been improved the dynamic response performance of control system with a single closed loop PI controller; And do not need phase-locked loop, only use simple mathematical to calculate just can to obtain synchronous anglec of rotation frequencies omega and be used for sine and the cosine sin θ _ cos θ at the θ angle of rotation transformation, simplify the control system structure, eliminated the dynamic delay that phase-locked loop brings simultaneously; At the control of double-fed generator pusher side current transformer, this control thinking also has good reference.Low cost of manufacture, production efficiency and stability are significantly carried; Have simple in structurely, the time easy to maintenance, reduced the workload advantages of higher of safeguarding.

Description of drawings

Fig. 1 is that prior art of the present invention is based on two closed-loop control frame schematic diagrams of the double-fed generator net side converter of phase-locked loop

Fig. 2 is the topological diagram of net side converter of the present invention

Fig. 3 theory diagram of the present invention

Embodiment

In the prior art, the conventional vector control technology is taked line voltage orientation, virtual electrical network flux linkage orientation etc. usually, by synchronous rotation transformation, is issued to the decoupling zero control of real component and idle component at the dq rotating coordinate system.Two closed loops are adopted in the control of real component, and outer shroud is the DC bus-bar voltage ring, and interior ring is the active current ring; Single electric current loop is adopted in the control of idle component, directly is given as reactive current.The sine and the cosine sin θ _ cos θ that control the θ angle that used synchronous anglec of rotation frequencies omega and rotation transformation use obtain by software phase-lock loop or hardware phase-locked-loop PLL.The direct Power Control technology adopts and the similar thinking of conventional vector control: take line voltage orientation, virtual electrical network flux linkage orientation etc., by synchronous rotation transformation, be issued to the decoupling zero control of real component and idle component at the dq rotating coordinate system.Two closed loops of real component are outer shroud DC bus-bar voltage ring, interior ring active power ring; The single closed loop of idle component is the reactive power ring, and the sine and the cosine sin θ _ cos θ that control the θ angle that used synchronous anglec of rotation frequencies omega and rotation transformation use obtain by software phase-lock loop or hardware phase-locked-loop PLL.To sum up, the something in common of these two kinds of control methods is: two closed loops are all adopted in the control of real component; Single closed loop is adopted in the control of idle component; All realizing meritorious and idle decoupling zero control under the rotation dq coordinate system synchronously; Synchronous anglec of rotation frequencies omega is all obtained by PLL in the sine at the θ angle that rotation transformation is used and cosine sin θ _ cos θ and the decoupling zero control.

As Fig. 2 to Fig. 3 in conjunction with shown in, the present invention is described in more detail: go out relation between net side converter control voltage and the DC bus-bar voltage according to the topological diagram of net side converter and three-phase voltage equation inference, be expressed as decoupling zero item and compensation term and; Derivation draws the computational methods of synchronous anglec of rotation frequencies omega; Derivation draws the computational methods for the sine at the θ angle of rotation transformation and cosine sin θ _ cos θ; According to The above results, obtain a kind of double-fed generator net side converter direct voltage control method theory diagram of no phase-locked loop.

The derivation of this example:

The first step, the step of the synchronous angular velocity of rotation ω draw line voltage of deriving is as follows:

Make the instantaneous value of three-phase voltage be:

$\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]=\left[\begin{array}{c}{U}_m\cos \left(\mathrm{\ωt}\right)\\ U_m\cos (\mathrm{\ωt}-\frac{2\mathrm{pi}}{3})\\ U_m\cos (\mathrm{\ωt}+\frac{2\mathrm{pi}}{3})\end{array}\right]---\left(16\right)$

In the formula, u _a, u _b, u _cIt is respectively the instantaneous value of three-phase voltage; U _mIt is the amplitude of phase voltage; ω is the synchronous angular velocity of rotation of line voltage.

According to abc_ α β constant amplitude transformation matrix, can obtain:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{c}{u}_a-\frac{1}{2}{u}_b-\frac{1}{2}{u}_c\\ \frac{\sqrt{3}}{2}{u}_b-\frac{\sqrt{3}}{2}{u}_c\end{array}\right]---\left(17\right)$

Wushu (16) substitution formula (17), and further dissolve and obtain u _αAnd u _βExpression formula as follows:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{c}{U}_m\cos \left(\mathrm{\ωt}\right)\\ U_m\sin \left(\mathrm{\ωt}\right)\end{array}\right]---\left(18\right)$

U _mcos(ωt)＝U _m cos[ω(t-Δt+Δt)]＝U _m cos[ω(t-Δt)]cosωΔt-U _m sin[ω(t-Δt)]sinωΔt （19）

Be u _α(t)=u _α(t-Δ t) cos ω Δ t-u _β(t-Δ t) sin ω Δ t (20)

U in like manner _β(t)=u _β(t-Δ t) cos ω Δ t+u _α(t-Δ t) sin ω Δ t (21)

Formula (21) phase shift obtains:

$u_{\mathrm{\β}}(t-\mathrm{\Δt})\frac{u_{\mathrm{\β}}\left(t\right)-u_{\mathrm{\α}}(t-\mathrm{\Δt})\sin \mathrm{\ω\Δt}}{\cos \mathrm{\ω\Δt}}---\left(22\right)$

Formula (22) substitution formula (20):

$u_{\mathrm{\α}}\left(t\right)=u_{\mathrm{\α}}(t-\mathrm{\Δt})\cos \mathrm{\ω\Δt}-\sin \mathrm{\ω\Δt}\frac{u_{\mathrm{\β}}\left(t\right)-u_{\mathrm{\α}}(t-\mathrm{\Δt})\sin \mathrm{\ω\Δt}}{\cos \mathrm{\ω\Δt}}\⇒$

$u_{\mathrm{\α}}\left(t\right)\cos \mathrm{\ω\Δt}=u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)\sin \mathrm{\ω\Δt}\⇒\cos \mathrm{\ω\Δt}=\frac{u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)\sin \mathrm{\ω\Δt}}{u_{\mathrm{\α}}\left(t\right)}---\left(23\right)$

Formula (23) substitution formula (21):

$u_{\mathrm{\β}}\left(t\right)=u_{\mathrm{\β}}(t-\mathrm{\Δt})*\frac{u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)\sin \mathrm{\ω\Δt}}{u_{\mathrm{\α}}\left(t\right)}+u_{\mathrm{\α}}(t-\mathrm{\Δt})\sin \mathrm{\ω\Δt}\⇒$

$\sin \mathrm{\ω\Δt}=\frac{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\β}}\left(t\right)-u_{\mathrm{\α}}(t-\mathrm{\Δt})u_{\mathrm{\β}}(t-\mathrm{\Δt})}{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)u_{\mathrm{\β}}(t-\mathrm{\Δt})}\≅\mathrm{\ω\Δt}---\left(24\right)$

Just can calculate the synchronous angular velocity of rotation ω of line voltage according to formula (24):

$\mathrm{\ω}=\frac{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\β}}\left(t\right)-u_{\mathrm{\α}}(t-\mathrm{\Δt})u_{\mathrm{\β}}(t-\mathrm{\Δt})}{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)u_{\mathrm{\β}}(t-\mathrm{\Δt})}*\frac{1}{\mathrm{\Δt}}---\left(25\right)$

Wherein Δ t is the sampling period of discretization, if sample frequency is 10kHz, and Δ t is the inverse of sample frequency, Δ t=0.0001 then, ω Δ t is the phase change value in the Δ t time, and t is very little for the ω Δ, thereby ω Δ t is approximately equal to ω Δ t sine function sin ω Δ t, and the error of bringing is very little, so error range is: ω Δ t=ω Δ t ± 0.0002.

Derivation draws for the step of the sine at the θ angle of rotation transformation and cosine sin θ _ cos θ as follows;

Three-phase voltage is carried out abc_ α β conversion, obtains:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_a\\ u_b\\ u_c\end{array}\right]---\left(26\right)$

In α β coordinate system, the sine and the cosine that are used for the synchronous anglec of rotation θ angle of rotation transformation can calculate by following formula:

$\left[\begin{array}{c}\cos \mathrm{\θ}\\ \sin \mathrm{\θ}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{\α}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\\ \frac{u_{\mathrm{\β}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\end{array}\right]---\left(27\right)$

In second step, according to the topological relation of double-fed generator net side converter, draw the three-phase voltage equation:

$\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]=R_g\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+L_g\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+\left[\begin{array}{c}{u}_{\mathrm{gca}}\\ u_{\mathrm{gcb}}\\ u_{\mathrm{gcc}}\end{array}\right]---\left(1\right)$

U wherein _GabcBe three phase network voltage, u _GcabcBe three-phase net side converter voltage, i _Ga, i _Gb, i _GcBe respectively three-phase net side converter electric current, L _gBe net side filter inductance, R _gBe net top-cross leakage resistance, C is the dc-link capacitance device, U _DcBe DC bus-bar voltage.

Carrying out the vector conversion according to synchronous rotating frame obtains:

Voltage equation:

$\left\{\begin{array}{c}{u}_{\mathrm{gd}}=R_g{i}_{\mathrm{gd}}+L_g{\mathrm{pi}}_{\mathrm{gd}}-\mathrm{\ω}{L}_g{i}_{\mathrm{gq}}+u_{\gcd }\\ u_{\mathrm{gq}}=R_g{i}_{\mathrm{gq}}+L_g{\mathrm{pi}}_{\mathrm{gq}}+\mathrm{\ω}{L}_g{i}_{\mathrm{gd}}+u_{\mathrm{gcq}}\end{array}\right.---\left(2\right)$

Wherein, ω is the synchronous angular velocity of rotation of line voltage, and p is differential operator.

Derive the input power P that the net side converter is sent into the real component controller of electrical network by voltage equation, power equation successively _gInput power Q with the idle component controller _gStep as follows;

Power equation:

$\left\{\begin{array}{c}{P}_g=\frac{3}{2}(u_{\mathrm{gd}}{i}_{\mathrm{gd}}+u_{\mathrm{gq}}{i}_{\mathrm{gq}})\\ Q_g=\frac{3}{2}(u_{\mathrm{gq}}{i}_{\mathrm{gd}}-u_{\mathrm{gd}}{i}_{\mathrm{gq}})\end{array}\right.---\left(3\right)$

Adopt the control of line voltage directional vector, then voltage vector direction and d axle in the same way, that is:

$\left\{\begin{array}{c}{u}_{\mathrm{gd}}=u_1\\ u_{\mathrm{gq}}=0\end{array}\right.---\left(4\right)$

U wherein ₁It is the amplitude of electrical network phase voltage.

Then:

$\left\{\begin{array}{c}{P}_g=\frac{3}{2}{u}_{\mathrm{gd}}{i}_{\mathrm{gd}}=\frac{3}{2}{u}_1{i}_{\mathrm{gd}}\\ Q_g=\frac{3}{2}(-u_{\mathrm{gd}}{i}_{\mathrm{gq}})=-\frac{3}{2}{u}_1{i}_{\mathrm{gq}}\end{array}\right.---\left(5\right)$

The relation between net side converter control voltage and the DC bus-bar voltage derived be double-fed generator net side frequency converter directly control voltage be decoupling zero item and compensation term and.

Wushu (5) substitution formula (2) is further derived and is obtained:

$\left\{\begin{array}{c}{u}_{\mathrm{gd}}=\frac{2R_g}{3u_1}{P}_g+\frac{2L_g}{3u_1}p{P}_g+\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\gcd }\\ u_{\mathrm{gq}}=-\frac{2R_g}{3u_1}{Q}_g-\frac{2L_g}{3u_1}p{Q}_g+\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gcq}}\end{array}\right.---\left(6\right)$

The following formula phase shift obtains:

$\left\{\begin{array}{c}{u}_{\gcd }=-\frac{2R_g}{3u_1}{P}_g-\frac{2L_g}{3u_1}p{P}_g-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{\mathrm{gcq}}=\frac{2R_g}{3u_1}{Q}_g+\frac{2L_g}{3u_1}p{Q}_g-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(7\right)$

According to power-balance, when not considering loss:

P _c＝P _e-P _g （8）

P _cBe the active power that flows into dc bus; P _gBe the active power that the net side converter is sent into electrical network; When the control of derivation net side converter, establish the active power P that flows into the dc bus side by the pusher side current transformer _eConstant is constant, establishes P _e=K; And

First formula with formula (8) substitution formula (7) obtains:

$u_{\gcd }=-\frac{2R_g}{3u_1}(K-P_c)-\frac{2L_g}{3u_1}p(K-P_c)-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}$

$=\frac{2R_g}{3u_1}{P}_c+\frac{2L_g}{3u_1}p{P}_c-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K---\left(9\right)$

$P_c=\frac{1}{2}C\frac{d}{\mathrm{<figure-callout\; id="2"\; label="dt\; U\; dc"\; filenames="DEST\_PATH\_HDA00003233206700021.png"\; state="\{\{state\}\}">dt</figure-callout>}}{U}_{\mathrm{dc}}^{}{}_2^{}$ Substitution formula (9)

$u_{\gcd }=\frac{R_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}+\frac{L_{g}C}{3u_1}\frac{d^2\left(U_{\mathrm{dc}}^2\right)}{{\mathrm{dt}}^2}-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K$

$=\frac{d}{\mathrm{dt}}(\frac{R_{g}C}{3u_1}{\mathrm{<figure-callout\; id="2"\; label="U\; dc"\; filenames="DEST\_PATH\_HDA00003233206700021.png"\; state="\{\{state\}\}">U</figure-callout>}}_{\mathrm{dc}}^{}+\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}})-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K---\left(10\right)$

First formula of formula (10) alternate form (7) obtains net side converter side voltage equation and is:

$\left\{\begin{array}{c}{u}_{\gcd }=\frac{d}{\mathrm{dt}}(\frac{R_{g}C}{3u_1}{\mathrm{<figure-callout\; id="2"\; label="U\; dc"\; filenames="DEST\_PATH\_HDA00003233206700021.png"\; state="\{\{state\}\}">U</figure-callout>}}_{\mathrm{dc}}^{}+\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}})-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K\\ u_{\mathrm{gcq}}=\frac{2R_g}{3u_1}{Q}_g+\frac{2L_g}{3u_1}p{Q}_g-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(11\right)$

Formula (11) can be expressed as the decoupling zero item and eliminate cross-linked compensation term addition.

The decoupling zero item is $\left\{\begin{array}{c}{u}_{\gcd }=\frac{d}{\mathrm{dt}}(\frac{R_{g}C}{3u_1}{\mathrm{<figure-callout\; id="2"\; label="U\; dc"\; filenames="DEST\_PATH\_HDA00003233206700021.png"\; state="\{\{state\}\}">U</figure-callout>}}_{\mathrm{dc}}^{}+\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}})\\ u_{\mathrm{gcq}}=\frac{2R_g}{3u_1}{Q}_g+\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right.---\left(12\right)$

Compensation term is $\left\{\begin{array}{c}{u}_{\gcd }=-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K\\ u_{\mathrm{gcq}}=-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(13\right)$

Generally, ignore net top-cross leakage resistance R _g, following formula (12～13) dissolve for:

The decoupling zero item is $\left\{\begin{array}{c}{u}_{\gcd }=\frac{d}{\mathrm{dt}}\left(\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}\right)\\ u_{\mathrm{gcq}}=\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right.---\left(14\right)$

Compensation term is $\left\{\begin{array}{c}{u}_{\gcd }=-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{\mathrm{gcq}}=-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(15\right)$

By formula (12) as can be known the input of real component controller be the DC bus-bar voltage set-point square

With the DC bus-bar voltage measured value square The The whole control equation is single closed loop, only needs a PI controller just can finish the control of DC bus-bar voltage; The input of idle component controller is reactive power set-point Q _{G_ref}With wattless power measurement value Q _g, identical with the direct Power Control technology.

The 3rd step, the DC bus-bar voltage set-point square with the DC bus-bar voltage measured value square ask poor, obtain error amount, send into the PI controller, obtain the decoupling zero item through the PI controller, itself and compensation term addition, just the d axle component of controlled voltage.

The 4th step, reactive power set-point and wattless power measurement value ask poor, obtain error amount, send into the PI controller, obtain the decoupling zero item through the PI controller, itself and compensation term addition, just the q axle component of controlled voltage.

In the 5th step, d, q axle control voltage are sent into the pwm signal generation module, generate pwm signal and export to the IGBT unit.

According to above-mentioned theoretical derivation result, draw the double-fed generator net side converter direct voltage control method theory diagram of a kind of no phase-locked loop as shown in Figure 3.

More than one embodiment of the present of invention are had been described in detail, but described content only is preferred embodiment of the present invention, can not be considered to for limiting practical range of the present invention.All equalizations of doing according to the present patent application scope change and improve etc., all should still belong within the patent covering scope of the present invention.

Claims (7)

1. the double-fed generator net side converter direct voltage control method of a no phase-locked loop is characterized in that:

The first step,

Derivation draws the synchronous angular velocity of rotation ω of line voltage,

Derivation draws for the sine at the θ angle of rotation transformation and cosine sin θ _ cos θ,

Second step,

Topological relation according to the net side converter draws the three-phase voltage equation;

Derive the input power P that the net side converter is sent into the real component controller of electrical network by voltage equation, power equation successively _gInput power Q with the idle component controller _g,

The relation between net side converter control voltage and the DC bus-bar voltage derived be double-fed generator net side frequency converter directly control voltage be decoupling zero item and compensation term and;

The 3rd step,

The DC bus-bar voltage set-point square with the DC bus-bar voltage measured value square ask poor, obtain error amount, send into the PI controller, obtain the decoupling zero item through the PI controller, itself and compensation term addition, just the d axle component of controlled voltage;

The 4th step,

Reactive power set-point and wattless power measurement value ask poor, obtain error amount, send into the PI controller, obtain the decoupling zero item through the PI controller, itself and compensation term addition, just the q axle component of controlled voltage;

The 5th step,

D, q axle control voltage are sent into the pwm signal generation module, generate pwm signal and export to the IGBT unit.

2. the double-fed generator net side converter direct voltage control method of no phase-locked loop according to claim 1, it is characterized in that: the formula of the synchronous angular velocity of rotation ω of described line voltage is:

$\mathrm{\&omega;}=\frac{u_{\mathrm{\&alpha;}}\left(t\right)u_{\mathrm{\&beta;}}\left(t\right)-u_{\mathrm{\&alpha;}}(t-\mathrm{\&Delta;t})u_{\mathrm{\&beta;}}(t-\mathrm{\&Delta;t})}{u_{\mathrm{\&alpha;}}\left(t\right)u_{\mathrm{\&alpha;}}(t-\mathrm{\&Delta;t})-u_{\mathrm{\&beta;}}\left(t\right)u_{\mathrm{\&beta;}}(t-\mathrm{\&Delta;t})}*\frac{1}{\mathrm{\&Delta;t}}.$

3. the double-fed generator net side converter direct voltage control method of no phase-locked loop according to claim 1 is characterized in that: the sine at described θ angle for rotation transformation and the formula of cosine sin θ _ cos θ are:

$\left[\begin{array}{c}\cos \mathrm{\&theta;}\\ \sin \mathrm{\&theta;}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{\&alpha;}}}{\sqrt{{u_{\mathrm{\&alpha;}}}^2+{u_{\mathrm{\&beta;}}}^2}}\\ \frac{u_{\mathrm{\&beta;}}}{\sqrt{{u_{\mathrm{\&alpha;}}}^2+{u_{\mathrm{\&beta;}}}^2}}\end{array}\right].$

4. the double-fed generator net side converter direct voltage control method of no phase-locked loop according to claim 1, it is characterized in that: the formula of described three-phase voltage equation is: $\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]=R_g\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+$ $L_g\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+\left[\begin{array}{c}{u}_{\mathrm{gca}}\\ u_{\mathrm{gcb}}\\ u_{\mathrm{gcc}}\end{array}\right].$

5. the double-fed generator net side converter direct voltage control method of no phase-locked loop according to claim 1 is characterized in that: the input power P of described real component controller _gInput power Q with the idle component controller _gFormula be: $\left\{\begin{array}{c}{P}_g=\frac{3}{2}{u}_{\mathrm{gd}}{i}_{\mathrm{gd}}=\frac{3}{2}{u}_1{i}_{\mathrm{gd}}\\ Q_g=\frac{3}{2}(-u_{\mathrm{gd}}{i}_{\mathrm{gq}})=-\frac{3}{2}{u}_1{i}_{\mathrm{gq}}\end{array}\right..$

6. the double-fed generator net side converter direct voltage control method of no phase-locked loop according to claim 1, it is characterized in that: the formula of described decoupling zero item is: $\left\{\begin{array}{c}{u}_{\gcd }=\frac{d}{\mathrm{dt}}\left(\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}\right)\\ u_{\mathrm{gcq}}=\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right..$

7. the double-fed generator net side converter direct voltage control method of no phase-locked loop according to claim 1, it is characterized in that: the formula of described compensation term is: $\left\{\begin{array}{c}{u}_{\gcd }=-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{\mathrm{gcq}}=-\frac{2\mathrm{\&omega;}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right..$

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