CN103259290B - A kind of double-fed generator net side converter direct voltage control method of no phase-locked loop - Google Patents

Abstract

The invention provides a kind of double-fed generator net side converter direct voltage control method of no phase-locked loop, step is as follows: the synchronous rotary angular velocity omega deriving line voltage, derives the θ angle trigonometric function sin θ _ cos θ for rotation transformation; Derive three-phase voltage equation; Derive the input power P that net side converter sends into the real component controller of electrical network _gwith the input power Q of idle component controller _g, derive the relation between net side converter control voltage and DC bus-bar voltage; Derive the d axle component of control voltage and the q axle component of control voltage; D, q axle control voltage sends into pwm signal generation module, generates pwm signal and exports to IGBT unit.The invention has the beneficial effects as follows and just can realize, to effective control of DC bus-bar voltage, improve the dynamic response performance of control system with a single closed loop PI controller; Low cost of manufacture, production efficiency and stability such as significantly to put forward at the advantage.

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 field of power distribution, 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, rapidly, various technology is gradually improved in wind power generation development.Double-fed generator, as one of the critical piece of Wind turbines, adopts two PWM converter back-to-back to realize its variable speed constant frequency generator.Two PWM converter comprises net side converter and pusher side current transformer.The control planning of net side converter injects the power factor of electrical network to the stable of DC bus-bar voltage and safety, net side converter.For the control of net side converter, existing at present have conventional vector control technology and direct Power Control technology.Conventional vector control technology takes grid voltage orientation, virtual electrical network flux linkage orientation etc. usually, by synchronous rotation transformation, is issued to the uneoupled control of real component and idle component at dq rotating coordinate system.The control of real component adopts two close cycles, and outer shroud is DC bus-bar voltage ring, and inner ring is active current ring; The control of idle component adopts single electric current loop, directly to being decided to be reactive current.Sine and cosine sin θ _ cos θ at the θ angle that the synchronous rotary angular velocity omega of the line voltage used by control and rotation transformation are used are obtained by software phase-lock loop or hardware phase-locked-loop PLL.Direct Power Control technology adopts and controls similar thinking with conventional vector: take grid voltage orientation, virtual electrical network flux linkage orientation etc., by synchronous rotation transformation, be issued to the uneoupled control of real component and idle component at dq rotating coordinate system.The two close cycles of real component is outer shroud DC bus-bar voltage ring, inner ring active power ring; Idle component list closed loop is reactive power ring, and sine and cosine sin θ _ cos θ at the θ angle that the synchronous rotary angular velocity omega of the line voltage used by control and rotation transformation are used are obtained 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: the control of real component all adopts two close cycles; The control of idle component adopts single closed loop; All under synchronous rotary dq coordinate system, realize meritorious and idle uneoupled control; In the sine at the θ angle that rotation transformation is used and cosine sin θ _ cos θ and uneoupled control, the synchronous rotary angular velocity omega of line voltage is all obtained by PLL.Difference is: what conventional vector control technology controlled in fact is the electric current exchanged between net side converter and electrical network, and direct Power Control technical controlling is the power exchanged between net side converter and electrical network.

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

1. the control of real component adopts two close cycles, and outer shroud is DC bus-bar voltage ring, and inner ring is power ring or electric current loop, needs two PI controllers, controller parameter at least 4, can increase difficulty and the complexity of system debug; And when given changing, two PI controllers have two Dynamic Regulating Process, the dynamic property of meeting influential system; The unreasonable configuration of final parameter also may the reliability of influential system.

2. control effects relies on phase-locked loop, and the dynamic characteristic of phase-locked loop may affect the dynamic characteristic of control effects.Phase-locked loop inside containing PI controller, the debugging of its parameter and it is very large on the impact of whole system control effects.

Summary of the invention

The problem to be solved in the present invention is to provide a kind of Circuits System of power supply of power field, is especially 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,

Derive and draw the synchronous rotary angular speed of line voltage wherein, Δ t is the sampling period of discretization, and what t represented is a certain moment;

Pass through $\left[\begin{array}{c}\cos \mathrm{\θ}\\ \sin \mathrm{\θ}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{\α}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\\ \frac{u_{\mathrm{\β}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\end{array}\right]$ Derive and draw sine for the θ angle of rotation transformation and cosine sin θ _ cos θ;

Second step,

Three-phase voltage equation is drawn according to the topological relation of net side converter;

The input power P that net side converter sends into the real component controller of electrical network is derived successively by voltage equation, power equation _gwith the input power Q of idle component controller _g,

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

3rd step,

DC bus-bar voltage set-point square with DC bus-bar voltage measured value square ask poor, obtain error amount, send into PI controller, obtain decoupling zero item through PI controller, it is added with compensation term, just obtains the d axle component of control voltage;

4th step,

Reactive power set-point and wattless power measurement value ask poor, obtain error amount, send into PI controller, obtain decoupling zero item through PI controller, it is added with compensation term, just obtains the q axle component of control voltage;

5th step,

D, q axle control voltage sends into pwm signal generation module, generates pwm signal and exports to IGBT unit.

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

$\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]=R_g\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+L_g\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+\left[\begin{array}{c}{u}_{\mathrm{gca}}\\ u_{\mathrm{gcb}}\\ u_{\mathrm{gcc}}\end{array}\right],$ Wherein u _gabcthree-phase power grid voltage, u _gcabcthree-phase net side converter voltage, i _ga, i _gb, i _gcthree-phase net side converter electric current respectively, L _g, be net side filter inductance, R _git is net top-cross leakage resistance.

Further, the input power P of described real component controller _gwith the input power Q of idle component controller _gformula be: $\left\{\begin{array}{c}{P}_g=\frac{3}{2}{u}_{\mathrm{gd}}{i}_{\mathrm{gd}}=\frac{3}{2}{u}_1{i}_{\mathrm{gd}}\\ Q_g=\frac{3}{2}(-u_{\mathrm{gd}}{i}_{\mathrm{gq}})=-\frac{3}{2}{u}_1{i}_{\mathrm{gq}}\end{array}\right.,$ Wherein, u _gdthe d axle component of line voltage, u _gqthe q axle component of line voltage, i _gdthe d axle component of current on line side, i _gqthe q axle component of current on line side, u ₁it is the amplitude of electrical network phase voltage.

Further, the formula of described decoupling zero item is: $\left\{\begin{array}{c}{u}_{g1d}=\frac{d}{\mathrm{dt}}\left(\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}\right)\\ u_{g1q}=\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right.,$ Wherein, u _g1dthe d axle component of decoupling zero item, u _g1qit is the q axle component of decoupling zero item.

Further, the formula of described compensation term is: $\left\{\begin{array}{c}{u}_{g2d}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{g2q}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.,$ Wherein, u _g2dthe d axle component of compensation term, u _g2qit is the q axle component of compensation term.

The advantage that the present invention has and good effect are: control double-fed generator net side converter owing to adopting direct voltage control method, without the need to adopting phase-locked loop, only with a single closed loop PI controller just can realize to DC bus-bar voltage fast and effectively control, improve the dynamic response performance of control system; And do not need phase-locked loop, only use simple mathematical computations just can obtain synchronous rotary angular frequency and for the sine at the θ angle of rotation transformation and cosine sin θ _ cos θ, simplify Control system architecture, eliminate the dynamic delay that phase-locked loop brings simultaneously; For the control of double-fed generator pusher side current transformer, this controls thinking also the well property used for reference.Low cost of manufacture, production efficiency and stability are significantly carried; There is structure simple, while easy to maintenance, decrease the workload advantages of higher of maintenance.

Accompanying drawing explanation

Fig. 1 is the double-closed-loop control frame schematic diagram of prior art of the present invention based on 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

As shown in Figure 1, in prior art, conventional vector control technology takes grid voltage orientation, virtual electrical network flux linkage orientation etc. usually, by synchronous rotation transformation, is issued to the uneoupled control of real component and idle component at dq rotating coordinate system.The control of real component adopts two close cycles, and outer shroud is DC bus-bar voltage ring, and inner ring is active current ring; The control of idle component adopts single electric current loop, directly to being decided to be reactive current.Sine and cosine sin θ _ cos θ at the θ angle that the synchronous rotary angular frequency used by control and rotation transformation are used are obtained by software phase-lock loop or hardware phase-locked-loop PLL.Direct Power Control technology adopts and controls similar thinking with conventional vector: take grid voltage orientation, virtual electrical network flux linkage orientation etc., by synchronous rotation transformation, be issued to the uneoupled control of real component and idle component at dq rotating coordinate system.The two close cycles of real component is outer shroud DC bus-bar voltage ring, inner ring active power ring; Idle component list closed loop is reactive power ring, and sine and cosine sin θ _ cos θ at the θ angle that the synchronous rotary angular frequency used by control and rotation transformation are used are obtained 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: the control of real component all adopts two close cycles; The control of idle component adopts single closed loop; All under synchronous rotary dq coordinate system, realize meritorious and idle uneoupled control; In the sine at the θ angle that rotation transformation is used and cosine sin θ _ cos θ and uneoupled control, synchronous rotary angular frequency is all obtained by PLL.

As shown in Fig. 2 to Fig. 3 combines, the present invention is described in more detail: go out the relation between net side converter control voltage and 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; Derive and draw the computational methods of synchronous rotary angular frequency; Derive and draw the computational methods of sine for 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 And Principle block diagram of no phase-locked loop.

The derivation of this example:

The first step, derive and show that the step of the synchronous rotary angular velocity omega of line voltage is as follows:

The instantaneous value of three-phase voltage is made to 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 formula, u _a, u _b, u _cthe instantaneous value of three-phase voltage respectively; U _mit is the amplitude of phase voltage; ω is the synchronous rotary angular speed 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) substitutes into formula (17), and dissolves further 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 _mcos[ω(t-Δt+Δt)]＝U _mcos[ω(t-Δt)]cosωΔt-U _msin[ω(t-Δt)]sinωΔt (19)

I.e. u _α(t)=u _α(t-Δ t) cos ω Δ t-u _β(t-Δ t) sin ω Δ t (20)

In like manner u _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) substitutes into 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) substitutes into formula (21):

$\begin{array}{c}{u}_{\mathrm{\β}}\left(t\right)=u_{\mathrm{\β}}(t-\mathrm{\Δt})*\frac{u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)\sin \mathrm{\ω\Δt}}{u_{\mathrm{\α}}\left(t\right)}+u_{\mathrm{\α}}(t-\mathrm{\Δt})\sin \mathrm{\ω\Δt}\⇒\\ \sin \mathrm{\ω\Δt}=\frac{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\β}}\left(t\right)-u_{\mathrm{\α}}(t-\mathrm{\Δt})u_{\mathrm{\β}}(t-\mathrm{\Δt})}{u_{\mathrm{\α}}\left(t\right)u_{\mathrm{\α}}(t-\mathrm{\Δt})-u_{\mathrm{\β}}\left(t\right)u_{\mathrm{\β}}(t-\mathrm{\Δt})}\≅\mathrm{\ω\Δt}\end{array}---\left(24\right)$

Just the synchronous rotary angular velocity omega of line voltage can be calculated 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, then Δ t=0.0001, ω Δ t is the phase change value in the Δ t time, and ω Δ t is very little, and thus ω Δ t is approximately equal to ω Δ t sine function sin ω Δ t, and the error brought is very little, so error range is: ω Δ t=ω Δ t ± 0.0002.

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

Carry out abc_ α β to three-phase voltage to convert, obtain:

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

In α β coordinate system, for the sine at the synchronous rotary angle θ angle of rotation transformation and cosine by following formulae discovery:

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

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

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

Wherein u _gabcthree-phase power grid voltage, u _gcabcthree-phase net side converter voltage, i _ga, i _gb, i _gcthree-phase net side converter electric current respectively, L _g, be net side filter inductance, R _gbe net top-cross leakage resistance, C is DC bus capacitance, U _dcfor DC bus-bar voltage.

Carry out vector according to synchronous rotating frame to obtain:

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 rotary angular speed of line voltage, and p is differential operator.

The input power P that net side converter sends into the real component controller of electrical network is derived successively by voltage equation, power equation _gwith the input power Q of 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 grid voltage orientation vector control, then voltage vector direction and d axle are in the same way, that is:

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

Wherein u 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 derived between net side converter control voltage and DC bus-bar voltage to be the direct control voltage of double-fed generator net side frequency converter be decoupling zero item and compensation term and.

Wushu (5) substitutes into further derivation of formula (2) and obtains:

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

Above 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 _cthe active power flowing into DC bus; P _gthe active power that net side converter sends into electrical network; When the control of derivation net side converter, if flowed into the active-power P of DC bus side by pusher side current transformer _econstant is constant, if P _e=K; And

Formula (8) is substituted into the first formula of formula (7), obtains:

$\begin{array}{c}{u}_{\gcd }=-\frac{2R_g}{3u_1}(K-P_c)-\frac{2L_g}{3u_1}p(K-P_c)-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ =\frac{2R_g}{3u_1}{P}_c+\frac{2L_g}{3u_1}p{P}_c-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K\end{array}---\left(9\right)$

? $P_c=\frac{1}{2}C\frac{d}{\mathrm{dt}}{U}_{\mathrm{dc}}^2$ Substitution formula (9)

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

$=\frac{d}{\mathrm{dt}}(\frac{R_{g}C}{3u_1}{U}_{\mathrm{dc}}^2+\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}})-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K---\left(10\right)$

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

$\left\{\begin{array}{c}{u}_{\gcd }=\frac{d}{\mathrm{dt}}(\frac{R_{g}C}{3u_1}{U}_{\mathrm{dc}}^2+\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}})-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K\\ u_{\mathrm{gcq}}=\frac{2R_g}{3u_1}{Q}_g+\frac{2L_g}{3u_1}p{Q}_g-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(11\right)$

Formula (11) can be expressed as decoupling zero item and be added with the cross-linked compensation term of elimination.

Decoupling zero item is $\left\{\begin{array}{c}{u}_{g1d}=\frac{d}{\mathrm{dt}}({\frac{R_{g}C}{3u_1}U}_{\mathrm{dc}}^2+\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}})\\ u_{g1q}=\frac{2R_g}{3u_1}{Q}_g+\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right.---\left(12\right)$

Compensation term is $\left\{\begin{array}{c}{u}_{g2d}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}-\frac{2R_g}{3u_1}K\\ u_{g2q}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(13\right)$

Under normal circumstances, net top-cross leakage resistance R is ignored _g, above formula (12 ~ 13) dissolve for:

Decoupling zero item is $\left\{\begin{array}{c}{u}_{g1d}=\frac{d}{\mathrm{dt}}\left(\frac{L_{g}C}{3u_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}\right)\\ u_{g1q}=\frac{2L_g}{3u_1}\frac{d{Q}_g}{\mathrm{dt}}\end{array}\right.---\left(14\right)$

Compensation term is $\left\{\begin{array}{c}{u}_{g2d}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{g2q}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.---\left(15\right)$

By the input of the known real component controller of formula (12) be DC bus-bar voltage set-point square with DC bus-bar voltage measured value square whole governing equation is single closed loop, only needs a PI controller just can complete 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 direct Power Control technology.

3rd step, DC bus-bar voltage set-point square with DC bus-bar voltage measured value square ask poor, obtain error amount, send into PI controller, obtain decoupling zero item through PI controller, it is added with compensation term, just obtains the d axle component of control voltage.

4th step, reactive power set-point and wattless power measurement value ask poor, obtain error amount, send into PI controller, obtain decoupling zero item through PI controller, it is added with compensation term, just obtains the q axle component of control voltage.

5th step, d, q axle control voltage sends into pwm signal generation module, generates pwm signal and exports to IGBT unit.

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

Above one embodiment of the present of invention have been described in detail, but described content being only preferred embodiment of the present invention, can not being considered to for limiting practical range of the present invention.All equalizations done according to the present patent application scope change and improve, and all should still belong within patent covering scope of the present invention.

Claims (5)

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

The first step,

Derive and draw the synchronous rotary angular speed of line voltage wherein, Δ t is the sampling period of discretization, and what t represented is a certain moment;

Pass through $\left[\begin{array}{c}\cos \mathrm{\θ}\\ \sin \mathrm{\θ}\end{array}\right]=\left[\begin{array}{c}\frac{u_{\mathrm{\α}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\\ \frac{u_{\mathrm{\β}}}{\sqrt{{u_{\mathrm{\α}}}^2+{u_{\mathrm{\β}}}^2}}\end{array}\right]$ Derive and draw sine for the θ angle of rotation transformation and cosine sin θ _ cos θ;

Second step,

Three-phase voltage equation is drawn according to the topological relation of net side converter;

The input power P that net side converter sends into the real component controller of electrical network is derived successively by voltage equation, power equation _gwith the input power Q of idle component controller _g,

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

3rd step,

DC bus-bar voltage set-point square with DC bus-bar voltage measured value square ask poor, obtain error amount, send into PI controller, obtain decoupling zero item through PI controller, it is added with compensation term, just obtains the d axle component of control voltage;

4th step,

Reactive power set-point and wattless power measurement value ask poor, obtain error amount, send into PI controller, obtain decoupling zero item through PI controller, it is added with compensation term, just obtains the q axle component of control voltage;

5th step,

D, q axle control voltage sends into pwm signal generation module, generates pwm signal and exports to IGBT unit.

2. 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 formula of described three-phase voltage equation is: $\left[\begin{array}{c}{u}_{\mathrm{ga}}\\ u_{\mathrm{gb}}\\ u_{\mathrm{gc}}\end{array}\right]=R_g\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+$ $L_g\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{ga}}\\ i_{\mathrm{gb}}\\ i_{\mathrm{gc}}\end{array}\right]+\left[\begin{array}{c}{u}_{\mathrm{gca}}\\ u_{\mathrm{gcb}}\\ u_{\mathrm{gcc}}\end{array}\right],$ Wherein u _gabcthree-phase power grid voltage, u _gcabcthree-phase net side converter voltage, i _ga, i _gb, i _gcthree-phase net side converter electric current respectively, L _g, be net side filter inductance, R _git is net top-cross leakage resistance.

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 input power P of described real component controller _gwith the input power Q of idle component controller _gformula be: $\left\{\begin{array}{c}{P}_g=\frac{3}{2}{u}_{\mathrm{gd}}{i}_{\mathrm{gd}}=\frac{3}{2}{u}_1{i}_{\mathrm{gd}}\\ Q_d=\frac{3}{2}(-u_{\mathrm{gd}}{i}_{\mathrm{gq}})=-\frac{3}{2}{u}_1{i}_{\mathrm{gq}}\end{array}\right.,$ Wherein, u _gdthe d axle component of line voltage, u _gqthe q axle component of line voltage, i _gdthe d axle component of current on line side, i _gqthe q axle component of current on line side, u ₁it is the amplitude of electrical network phase voltage.

4. 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 formula of described decoupling zero item is: $\left\{\begin{array}{c}{u}_{g1d}=\frac{d}{\mathrm{dt}}\left(\frac{L_{g}C}{{3u}_1}\frac{d\left(U_{\mathrm{dc}}^2\right)}{\mathrm{dt}}\right)\\ u_{g1q}=\frac{2L_g}{3u_1}\frac{{\mathrm{dQ}}_g}{\mathrm{dt}}\end{array}\right.,$ Wherein, u _g1dthe d axle component of decoupling zero item, u _g1qit is the q axle component of decoupling zero item.

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 formula of described compensation term is: $\left\{\begin{array}{c}{u}_{g2d}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{Q}_g+u_{\mathrm{gd}}\\ u_{g2d}=-\frac{2\mathrm{\ω}{L}_g}{3u_1}{P}_g+u_{\mathrm{gq}}\end{array}\right.,$ Wherein, u _g2dthe d axle component of compensation term, u _g2qit is the q axle component of compensation term.