CN104466968A - DSTATCOM negative-sequence current cross coupling compensation control method - Google Patents

Abstract

The invention discloses a DSTATCOM negative-sequence current cross coupling compensation control method. Conventional dq conversion software phase-locking closed-loop control complexity is avoided by the adoption of a digital phase-locking method with a sine and cosine trigonometric function as a two-dimensional orthogonal basis. In addition, the complexity of current negative-sequence current compensation control coordinate conversion control is overcome, a cross coupling negative-sequence current control strategy is provided, cross coupling is carried out on the negative-sequence current closed-loop controller output value in the counterclockwise rotation dq coordinate system to the positive-sequence reactive current or positive-sequence harmonic current current-voltage conversion result, and unified space vector control is carried out.

Description

A kind of DSTATCOM negative-sequence current cross coupling compensation control method

Technical field

The present invention relates to, in particular a kind of DSTATCOM negative-sequence current cross coupling compensation control method.

Background technology

In recent years, due to the develop rapidly of power electronic technology, the application of various electronic power conversion devices in electric power system, industry, traffic and family is increasingly extensive, a large amount of imbalances, nonlinear-load, impact, wavy load and some single-phase Large Copacity loads is there is, the spot welding machine of such as, phase line power voltage supply in the industries such as automobile making, industrial ac arc furnace, electric railway etc. in electric power system.The negative phase-sequence that these loads produce, idle and harmonic current cause a large amount of electric loss of energy, and are on the rise, and threaten safety and the economical operation of electric power system.In user side power quality controlling, idle negative-sequence current compensation is the study hotspot in electrical engineering field always, compared with compensating with traditional SVC, TSC, the synchronous static passive compensation device of DSTATCOM power distribution network have the make-up time fast, can Continuous Compensation, do not produce resonance, can the advantages such as certain subharmonic be compensated.Therefore low pressure DSTATCOM is the more excellent approach of one solving above-mentioned custom power quality problem.

For the compensation of negative-sequence current, currently mainly adopt angle-style Scheme of Reactive Power Compensation in the industry.Passive: according to Steinmetz principle, pure idle branch road is adopted to carry out idle and comprehensive compensation that is negative phase-sequence, with the corner connection type reactive power compensator (adopting phase splitting compensation method in three-phase four-wire system connection) of the switching based on thyristor, but it is based on phase control techniques, response speed is slow, can produce harmonic current.Active type (SVG) corner connection scheme is a kind of good power quality controlling scheme, as shown in Figure 1, is made up of 3 H bridge power units, and by corner connection mode connecting system, it has fast response time, can carry out the comprehensive regulation of idle, negative phase-sequence and harmonic wave.In corner connection Scheme of Reactive Power Compensation, normal employing compensates susceptance based on the symmetrical component method of Steinmetz principle by line current phasor calculation, and the phasor relied on based on Periodic Mean is theoretical.The susceptance of phasor identification and complexity calculates and need spend the plenty of time, and cause larger time delay, be generally a more than grid cycle, real-time is poor.

Negative-sequence current method is compensated for corner connection type SVG, normally carry out sequence decomposition (or by instantaneous reactive algorithm) by CT detection line electric current and calculate negative-sequence current and positive sequence reactive current, then the negative phase-sequence calculated, reactive current line value carried out by the conversion of line phase coordinates the target compensation electric current that Coordinate Conversion obtains corner connection type SVG to value mutually and compensate.But this method exists two kinds of deficiencies, one is that compensation arrangement itself is made up of three single-phase H bridges, and the withstand voltage of power cell increases mutually, and power cell topological structure is complicated simultaneously; Two are target currents by line value be transformed into be worth mutually time, because line phase coefficient matrix is not full rank, thus known line current asks phase current to there is separate more, must increase constraints and just can obtain unique solution, which increase computational complexity and operand.

For the compensation of negative-sequence current, current Main target negative-sequence current is carried out in ABC time domain stagnant ring Direct Current Control or carry out stream pressure by closed-loop control in dq coordinate system being converted to target voltage, then be transformed in α β coordinate system and carry out SVPWM control.Positive-negative sequence target current all carries out controlling to need a large amount of Coordinate Conversion to calculate by these control methods respectively.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, provide a kind of DSTATCOM negative-sequence current cross coupling compensation control method.

The present invention is achieved by the following technical solutions: a kind of DSTATCOM negative-sequence current cross coupling compensation control method, comprises the steps:

Step one, structure initial phase be 0 standard sin cos functions obtain trigonometric function two-dimensional quadrature base, real-time sampling grid line instantaneous voltage, integration is carried out again after carrying out product with the orthogonal basis sine and cosine value of structure, obtaining grid line voltage fundamental positive sequence component phase place carries out phase-locked, obtain grid line voltage-phase, corresponding line voltage U can be obtained according to this phase place _aBphase place sine and cosine value and two frequency multiplication sine and cosine values, calculate corresponding phase voltage U simultaneously _aphase place sine and cosine value and two frequency multiplication sine and cosine values;

Step 2, according to the phase-locked result of step one, counterclockwise dq conversion and clockwise dq conversion are carried out, by transformation result respectively through trapper filtering to grid line voltage;

Step 3, the result of two carried out decoupling zero and obtain the positive sequence of three-phase electricity netting twine voltage and dq corresponding to negative sequence component sits target value;

The instantaneous value of step 4, real-time sampling load current, carries out counterclockwise dq conversion and dq conversion clockwise, by transformation result respectively through trapper filtering according to the phase-locked result of step one to load current value;

Step 5, the result of four carried out positive-negative sequence decoupling zero and obtain the positive sequence of load current and the corresponding dq of negative sequence component sits target value;

The instantaneous value of step 6, real-time sampling DSTATCOM output current, carries out counterclockwise dq conversion and dq conversion clockwise, by transformation result respectively through trapper filtering according to the phase-locked result of step one to output current value;

Step 7, the result of four carried out positive-negative sequence decoupling zero and obtain the positive sequence of DSTATCOM output current and the corresponding dq of negative sequence component sits target value;

Step 8, according to device control overflow, adopt DC voltage closed-loop control, its output valve is d axle target current, obtains the positive sequence reactive power compensation target current of DSTATCOM device according to the q axle result of step 5, obtains dress negative sequence compensation target current simultaneously;

Step 9, result according to three, the positive-negative sequence component of grid line voltage is converted to the positive-negative sequence component of phase voltage, according to the result of eight, the d axle under counterclockwise dq coordinate system and q axle carry out respectively the feed forward decoupling control of target current, and carry out PI closed-loop control;

Step 10, the result of the Feedforward Decoupling in dq coordinate system clockwise in step 9, closed-loop control is carried out cross-couplings in counterclockwise dq coordinate, realize the cross-coupling control of negative-sequence current, its essence negative sequence component closed-loop control result is coupled to positive sequence component to carry out unifying to control;

Step 11, the result of step 10 carried out inverse PARK and transform in α, β coordinate system and realize the conversion of stream pressure, carry out SVPWM control, realize target is idle and negative-sequence current compensates.

The present invention has the following advantages compared to existing technology: the invention provides a kind of DSTATCOM negative-sequence current cross coupling compensation control method, the method provides a kind of easy digital phase-locking method being reliably easy to realize, and avoids conventional dq to convert the complexity of software phlase locking closed-loop control and the inexactness of result.Employing is a kind of digital phase-locking method of two-dimensional quadrature base based on sine and cosine trigonometric function.And overcome the complexity of current negative-sequence current compensatory control Coordinate Conversion control, propose a kind of cross-couplings negative-sequence current control strategy, the output valve of negative-sequence current being carried out closed loop controller carries out cross-couplings to positive sequence reactive current being rotated counterclockwise in dq coordinate system, or positive sequence harmonic electric current, in stream pressure transformation result, carry out uniform spaces vector control.

Accompanying drawing explanation

Fig. 1 is corner connection DSTATCOM topological system structural representation.

Fig. 2 is that three phase full bridge star of the present invention connects DSTATCOM topological system structural representation.

Fig. 3 is that three phase full bridge star of the present invention connects DSTATCOM Mathematical Modeling schematic diagram.

Fig. 4 is CLARK, PARK coordinate transforming axle schematic diagram of application of the present invention.

Fig. 5 be the present invention use based on the phase-locked schematic diagram of sine and cosine orthogonal two-dimensional base.

Fig. 6 is this bright line voltage positive-negative sequence component decoupling zero point sequence schematic diagram.

Fig. 7 is load current positive-negative sequence component of the present invention decoupling zero point sequence schematic diagram.

Fig. 8 is DSTATCOM device output current positive-negative sequence component decoupling zero point sequence schematic diagram of the present invention.

Fig. 9 is the cross-coupling control compensation principle figure of idle and negative sequence component double-closed-loop control and negative sequence component of the present invention.

Embodiment

Elaborate to embodiments of the invention below, the present embodiment is implemented under premised on technical solution of the present invention, give detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

See Fig. 2-3, for three phase full bridge star of the present invention connect DSTATCOM topological system structural representation and for Mathematical Modeling structural representation, star DSTATCOM is connected in three-phase three-wire system power distribution network.Star DSTATCOM is three-phase Y-connection structure, and its topological structure is the three phase full bridge of low pressure or the chain H bridge composition of mesohigh, load current i _1a, i _1b, i _1ccomprise meritorious, idle, negative phase-sequence and harmonic current, wherein idle, negative phase-sequence and harmonic current injection electrical network, cause electrical network energy loss, threaten system stable operation.Star DSTATCOM output current i _ca, i _cb, i _ccidle with load current, negative phase-sequence is identical with harmonic current, direction is contrary.Star DSTATCOM output current superposes with described load current eliminates idle in described current on line side, negative phase-sequence and harmonic current, ensures the electrical network quality of power supply.

A kind of DSTATCOM negative-sequence current cross coupling compensation control method, comprises the steps:

Step one, structure initial phase be 0 standard sin cos functions obtain trigonometric function two-dimensional quadrature base, real-time sampling grid line instantaneous voltage, integration is carried out again after carrying out product with the orthogonal basis sine and cosine value of structure, obtaining grid line voltage fundamental positive sequence component phase place carries out phase-locked, obtain grid line voltage-phase, corresponding line voltage U can be obtained according to this phase place _aBphase place sine and cosine value and two frequency multiplication sine and cosine values, calculate corresponding phase voltage U simultaneously _aphase place sine and cosine value and two frequency multiplication sine and cosine values.

See Fig. 5, phase-locked for based on sin cos functions two-dimensional quadrature base, structure initial phase be 0 sin cos functions sinwt, coswt be two-dimensional quadrature base, if line voltage U _aBfundamental positive sequence phase place is wt+ θ ⁺, its amplitude is U _m, phase-locked object is to solve wt+ θ ⁺; By the U collected _aBbe multiplied with sinwt, coswt of structure respectively and make cycle inner product and obtain:

$\left\{\begin{array}{c}S1={\∫}_0^{2\mathrm{\π}}{U}_{\mathrm{ab}}*\left(\sin \mathrm{wt}\right)\mathrm{dwt}=U_m^{+}\cos {\mathrm{\θ}}^{+}---\left(1\right)\\ S2={\∫}_0^{2\mathrm{\π}}{U}_{\mathrm{ab}}*\left(\cos \mathrm{wt}\right)\mathrm{dwt}=U_m^{+}\sin {\mathrm{\θ}}^{+}---\left(2\right)\end{array}\right.$

Easily obtained by above formula

$U_m=\sqrt{{S_1}^2+{S_2}^2}---\left(3\right)$

Line voltage fundamental positive sequence component phase place can be obtained by trigonometric function operation according to formula (1), (2), (3) first-harmonic negative sequence component phase place corresponding phase voltage U is obtained with line mutual relation of electric voltage according to phase voltage _afirst-harmonic positive-negative sequence phase place be respectively above-mentioned method for solving is made inner product and is calculated the coefficient asked and should to consider during phase place caused by sample frequency in discretization process.

See CLARK, PARK coordinate transforming axle schematic diagram that Fig. 4 is application of the present invention, each coordinate transform battle array required for the present invention is defined as follows:

CLARK3 converts: $C_{32}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]$

CLARK3 inverse transformation: $C_{23}=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right],$

CLARK2 converts: $C_{22}=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}\frac{3}{2}& 0\\ \frac{\sqrt{3}}{2}& \sqrt{3}\end{array}\right],$

Counterclockwise PARK conversion: $C_{\mathrm{dq}}^{+}=\left[\begin{array}{cc}\sin \mathrm{wt}& -\cos \mathrm{wt}\\ -\cos \mathrm{wt}& -\sin \mathrm{wt}\end{array}\right],$

Counterclockwise PARK inverse transformation: $C_{\mathrm{dq}}^{-}=C_{\mathrm{dq}}^{+},$

Clockwise PARK conversion: $C_{\mathrm{dq}}^{-}=\left[\begin{array}{cc}-\sin \mathrm{wt}& -\cos \mathrm{wt}\\ -\cos \mathrm{wt}& \sin \mathrm{wt}\end{array}\right].$

Step 2, according to the phase-locked result of step one, counterclockwise dq conversion and clockwise dq conversion are carried out to grid line voltage, transformation result is filtered through trapper respectively.

Step 3, the result of step 2 carried out decoupling zero and obtain the positive sequence of three-phase electricity netting twine voltage and dq corresponding to negative sequence component sits target value.

Fig. 6 is the line voltage U of sampling _aB, U _bCcalculate equivalent phasevoltage positive-negative sequence component theory diagram, by U _aB, U _bCunder transforming to α β coordinate system by CLARK2, carry out converting the impact being intended to reduce zero-sequence component by CLARK2 with line voltage.

$\left[\begin{array}{c}{U}_{\mathrm{\α}}\\ U_{\mathrm{\β}}\end{array}\right]=C_{22}*\left[\begin{array}{c}{U}_{\mathrm{AB}}\\ U_{\mathrm{BC}}\end{array}\right]---\left(4\right)$

Make counterclockwise PARK to convert:

$\left[\begin{array}{c}{V}_d^{+}\\ V_q^{+}\end{array}\right]=C_{\mathrm{dq}}^{+}*\left[\begin{array}{c}{U}_{\mathrm{\α}}\\ U_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{c}\sqrt{\frac{3}{2}}{U}_m^{+}\cos {\mathrm{\θ}}^{+}\\ -\sqrt{\frac{3}{2}}{U}_m^{+}\sin {\mathrm{\θ}}^{+}\end{array}\right]+\left[\begin{array}{cc}\cos \left(2{\mathrm{\θ}}_L^{+}\right)& -\sin \left(2{\mathrm{\θ}}_L^{+}\right)\\ \sin \left(2{\mathrm{\θ}}_L^{+}\right)& \cos \left(2{\mathrm{\θ}}_L^{+}\right)\end{array}\right]*\left[\begin{array}{c}-\sqrt{\frac{3}{2}}{U}_m^{-}\cos {\mathrm{\θ}}^{-}\\ -\sqrt{\frac{3}{2}}{U}_m^{-}\sin {\mathrm{\θ}}^{-}\end{array}\right]---\left(5\right)$

Wherein for fundamental positive sequence amplitude, θ ⁺for fundamental positive sequence amount initial phase, for first-harmonic negative sequence component amplitude, θ ^-for first-harmonic negative sequence component initial phase, visible after counterclockwise PARK conversion gained dq axle component respectively containing DC component and two frequency multiplication alternating current components, its DC component is fundamental positive sequence corresponding conversion value, two frequency multiplication alternating current components are negative sequence component coupling value, generally aberration rate is very little to consider system voltage, quick for calculating, do not consider harmonic component in transfer process, entirety does not affect testing result.Equally, also there are DC component and two frequency multiplication alternating current components in clockwise PARK transformation results, the corresponding first-harmonic negative sequence component of its DC component, alternating current component is positive sequence component coupling value;

Make clockwise PARK to convert:

$\left[\begin{array}{c}{V}_d^{+}\\ V_q^{+}\end{array}\right]=C_{\mathrm{dq}}^{+}*\left[\begin{array}{c}{U}_{\mathrm{\α}}\\ U_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{c}-\sqrt{\frac{3}{2}}{U}_m^{-}\cos {\mathrm{\θ}}^{-}\\ -\sqrt{\frac{3}{2}}{U}_m^{-}\sin {\mathrm{\θ}}^{-}\end{array}\right]+\left[\begin{array}{cc}\cos \left(2{\mathrm{\θ}}_L^{+}\right)& \sin \left(2{\mathrm{\θ}}_L^{+}\right)\\ \mathrm{-sin}\left(2{\mathrm{\θ}}_L^{+}\right)& \cos \left(2{\mathrm{\θ}}_L^{+}\right)\end{array}\right]*\left[\begin{array}{c}\sqrt{\frac{3}{2}}{U}_m^{+}\cos {\mathrm{\θ}}^{+}\\ -\sqrt{\frac{3}{2}}{U}_m^{+}\sin {\mathrm{\θ}}^{+}\end{array}\right]---\left(6\right)$

Order $\left[\begin{array}{c}\stackrel{\‾}{V_{\mathrm{ld}}^{+}}\\ \stackrel{\‾}{V_{\mathrm{lq}}^{+}}\end{array}\right]=\left[\begin{array}{c}\sqrt{\frac{3}{2}}{U}_m^{+}\cos {\mathrm{\θ}}^{+}\\ -\sqrt{\frac{3}{2}}{U}_m^{+}\sin {\mathrm{\θ}}^{+}\end{array}\right]---\left(7\right)$

$\left[\begin{array}{c}\stackrel{\‾}{V_{\mathrm{ld}}^{-}}\\ \stackrel{\‾}{V_{\mathrm{lq}}^{-}}\end{array}\right]=\left[\begin{array}{c}-\sqrt{\frac{3}{2}}{U}_m^{-}\cos {\mathrm{\θ}}^{-}\\ -\sqrt{\frac{3}{2}}{U}_m^{-}\sin {\mathrm{\θ}}^{-}\end{array}\right]---\left(8\right)$

According to (5), (6) two formula design lines voltage positive-negative sequence Decoupling networks, two frequency multiplication alternating current components counterclockwise, clockwise in PARK transformation results are removed and realizes full decoupled in dq coordinate system of positive-negative sequence component.Consider accuracy of detection and real-time, the present invention adopts secondary trapper to realize two frequency multiplication alternating current component filtering, obtains DC component under the positive and negative dq coordinate system of voltage

Final consideration DSTATCOM device adopts space S VPWM modulation compensated, thus the component in line voltage positive-negative sequence dq coordinate system is converted to the value of equivalent phasevoltage in corresponding coordinate system

The instantaneous value of step 4, real-time sampling load current, carries out counterclockwise dq conversion and dq conversion clockwise, by transformation result respectively through trapper filtering according to the phase-locked result of step one to load current value.

Step 5, the result of step 4 carried out positive-negative sequence decoupling zero and obtain the positive sequence of load current and the corresponding dq of negative sequence component sits target value.

The instantaneous value of step 6, real-time sampling DSTATCOM output current, carries out counterclockwise dq conversion and dq conversion clockwise, by transformation result respectively through trapper filtering according to the phase-locked result of step one to output current value.

Step 7, the result of step 4 carried out positive-negative sequence decoupling zero and obtain the positive sequence of DSTATCOM output current and the corresponding dq of negative sequence component sits target value.

Step 8, according to device control overflow, adopt DC voltage closed-loop control, its output valve is d axle target current, obtains the positive sequence reactive power compensation target current of DSTATCOM device according to the q axle result of step 5, obtains dress negative sequence compensation target current simultaneously.

Fig. 7 is load current idle component and negative sequence component solution procedure, its solution procedure and voltage positive-negative sequence component solution procedure similar, to consider in load current that harmonic content is large, adopt second-order low-pass filter to carry out alternating current component filtering solving in first-harmonic positive-negative sequence component.Finally obtain wherein for fundamental positive sequence reactive current, for the value of first-harmonic negative sequence component in up time dq coordinate system.Also harmonic component can be asked for by this method.

Fig. 8 is DSTATCOM output current positive-negative sequence component solution procedure, its solution procedure and load current positive-negative sequence component solution procedure similar, finally obtain wherein for fundamental positive sequence active current, device is got real component from net side draught and is maintained dc-voltage balance, for device compensating load fundamental positive sequence reactive current, for the value of device first-harmonic negative sequence component in up time dq coordinate system, in order to compensating load electric current negative sequence component.Also harmonic compensation can be carried out by this control principle.

Step 9, result according to step 3, the positive-negative sequence component of grid line voltage is converted to the positive-negative sequence component of phase voltage, according to the result of eight, the d axle under counterclockwise dq coordinate system and q axle carry out respectively the feed forward decoupling control of target current, and carry out PI closed-loop control.

Step 10, the result of the Feedforward Decoupling in dq coordinate system clockwise in step 9, closed-loop control is carried out cross-couplings in counterclockwise dq coordinate, realize the cross-coupling control of negative-sequence current, its essence negative sequence component closed-loop control result is coupled to positive sequence component to carry out unifying to control.

Step 11, the result of step 10 carried out inverse PARK and transform in α, β coordinate system and realize the conversion of stream pressure, carry out SVPWM control, realize target is idle and negative-sequence current compensates.

Fig. 9 is reactive current Feedforward Decoupling double-closed-loop control compensation process and negative-sequence current Feedforward Decoupling double-closed-loop control cross-coupling control process.A Voltage loop and four electric current loops are had respectively, in Voltage loop in figure for direct voltage Setting signal, U _dcfor direct voltage measured signal, the two controls through PI, and it controls the Setting signal of Output rusults as positive sequence active current ring, with device output current component composition positive sequence active current ring controls, and object is that device receives active current from net side draught, maintains DC voltage stability; Equally, load positive sequence idle component as positive sequence reactive current ring control objectives after negate, export positive sequence idle component with device composition positive sequence reactive current control ring, in order to compensating load positive sequence reactive current; Negative-sequence current component and forward-order current adopt same current ring to control; Gaining merit and idle component full decoupled to realize positive-negative sequence, present invention employs feed forward decoupling control; Meanwhile, in order to suppress grid disturbances, in control, voltage feed-forward control controls.

The object of carrying out Voltage loop and current loop control is to realize the conversion of stream pressure, obtains device brachium pontis side and exports target voltage, realizes the conversion of stream pressure.

Device negative-sequence current closed loop is worth under obtaining the clockwise dq coordinate system of brachium pontis side negative phase-sequence target voltage, the present invention adopts the method negative phase-sequence target voltage of negative-sequence current cross-coupling control to be coupled in the counterclockwise dq coordinate system of positive sequence by cross-couplings transformation matrix to carry out unifying to control space vector SVPWM and control, and cross-coupling matrices is:

$C_{\mathrm{NP}}=\left[\begin{array}{cc}\cos \left(2{\mathrm{\θ}}_P^{+}\right)& \sin \left(2{\mathrm{\θ}}_P^{+}\right)\\ -\sin \left(2{\mathrm{\θ}}_P^{+}\right)& \cos \left(2{\mathrm{\θ}}_P^{+}\right)\end{array}\right]---\left(9\right)$

Negative phase-sequence target voltage is superimposed with positive sequence target voltage in cross-couplings to counterclockwise dq coordinate system obtains total dq coordinate system target voltage $\left[\begin{array}{c}{V}_d\\ V_q\end{array}\right],$ It is obtained through counterclockwise PARK inverse transformation:

$\left[\begin{array}{c}{V}_{\mathrm{\α}}\\ V_{\mathrm{\β}}\end{array}\right]=C_{\mathrm{dq}}^{-}*\left[\begin{array}{c}{V}_d\\ V_q\end{array}\right]=\left[\begin{array}{cc}-\sin {\mathrm{\θ}}_P& -\cos {\mathrm{\θ}}_P\\ -\cos {\mathrm{\θ}}_P& \sin {\mathrm{\θ}}_P\end{array}\right]*\left[\begin{array}{c}{V}_d\\ V_q\end{array}\right]---\left(10\right)$

With $\left[\begin{array}{c}{V}_{\mathrm{\α}}\\ V_{\mathrm{\β}}\end{array}\right]$ Carry out SVPWM and compensate the positive sequence reactive current and negative sequence component compensation that finally achieve device.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (2)

1. a DSTATCOM negative-sequence current cross coupling compensation control method, is characterized in that, comprise the steps:

Step one, structure initial phase be 0 standard sin cos functions obtain trigonometric function two-dimensional quadrature base, real-time sampling grid line instantaneous voltage, integration is carried out again after carrying out product with the orthogonal basis sine and cosine value of structure, obtaining grid line voltage fundamental positive sequence component phase place carries out phase-locked, obtain grid line voltage-phase, corresponding line voltage U can be obtained according to this phase place _aBphase place sine and cosine value and two frequency multiplication sine and cosine values, calculate corresponding phase voltage U simultaneously _aphase place sine and cosine value and two frequency multiplication sine and cosine values;

Step 2, according to the phase-locked result of step one, counterclockwise dq conversion and clockwise dq conversion are carried out, by transformation result respectively through trapper filtering to grid line voltage;

Step 3, the result of step 2 carried out decoupling zero and obtain the positive sequence of three-phase electricity netting twine voltage and dq corresponding to negative sequence component sits target value;

The instantaneous value of step 4, real-time sampling load current, carries out counterclockwise dq conversion and dq conversion clockwise, by transformation result respectively through trapper filtering according to the phase-locked result that step one obtains to load current value;

Step 5, the result of four carried out positive-negative sequence decoupling zero and obtain the positive sequence of load current and the corresponding dq of negative sequence component sits target value;

The instantaneous value of step 6, real-time sampling DSTATCOM output current, carries out counterclockwise dq conversion and dq conversion clockwise, by transformation result respectively through trapper filtering according to the phase-locked result that step one obtains to output current value;

Step 7, the result of step 4 carried out positive-negative sequence decoupling zero and obtain the positive sequence of DSTATCOM output current and the corresponding dq of negative sequence component sits target value;

Step 8, according to device control overflow, adopt DC voltage closed-loop control, its output valve is d axle target current, obtains the positive sequence reactive power compensation target current of DSTATCOM device according to the q axle result of step 5, obtains dress negative sequence compensation target current simultaneously;

Step 9, result according to step 3, the positive-negative sequence component of grid line voltage is converted to the positive-negative sequence component of phase voltage, according to the result of eight, the d axle under counterclockwise dq coordinate system and q axle carry out respectively the feed forward decoupling control of target current, and carry out PI closed-loop control;

Step 10, the result of the Feedforward Decoupling in dq coordinate system clockwise in step 9, closed-loop control is carried out cross-couplings in counterclockwise dq coordinate, realize the cross-coupling control of negative-sequence current, its essence negative sequence component closed-loop control result is coupled to positive sequence component to carry out unifying to control;

Step 11, the result of step 10 carried out inverse PARK and transform in α β coordinate system and realize the conversion of stream pressure, carry out SVPWM control, realize target is idle and negative-sequence current compensates.

2. a kind of DSTATCOM negative-sequence current cross coupling compensation control method according to claim 1, is characterized in that: obtain line voltage fundamental positive sequence component phase place according to step one first-harmonic negative sequence component phase place corresponding phase voltage U is obtained with line mutual relation of electric voltage according to phase voltage _afirst-harmonic positive-negative sequence phase place be respectively