CN102904267A - Dynamic reactive power compensation open-loop control device and method - Google Patents

Abstract

The invention discloses a dynamic reactive power compensation open-loop control device and a dynamic reactive power compensation open-loop control method. The device comprises a three-phase alternating current circuit, a load, and a compensation circuit susceptance calculation module and three channels of compensators, which are in bridge connection with two ends of the load, wherein each compensator is used for compensating inductive reactive power which is required by a three-phase power system; and the compensation circuit susceptance calculation module is used for calculating susceptance which is required by a compensation circuit in real time according to three-phase voltage and current data of the load, calculating a thyristor control angle by using an interpolation method according to a relation between a susceptance amplification coefficient and the thyristor control angle, acting a control angle signal on the compensators, and regulating the inductive reactive power of a compensator circuit. By the invention, the aim of adjusting the equivalent reactance of the compensation circuit in real time according to load change can be fulfilled, so each phase of reactive power of a load system approaches zero, and a real-time reactive power compensation effect is achieved.

Description

Dynamic passive compensation open ring control device and method thereof

Technical field

The present invention relates to the reactive power compensator designing technique, relate in particular to dynamic passive compensation open ring control device and method thereof in the power supply system.

Background technology

In the industrial electric power systems such as iron and steel, metallurgy, need to carry out dynamic passive compensation to system owing to the variation of load, at present control method commonly used is that proportion of utilization-integration-differential (PID) control algolithm is carried out the idle control of closed loop to system, because the variation of load causes control system comparatively complicated aspect adjusting at pid parameter.And for load variations system slowly, can adopt the mode of open loop control that system is carried out dynamic passive compensation, avoided the parameter adjustment of closed-loop control complexity, so a kind of open loop reactive power compensation strategy based on load is proposed in the present invention.

Summary of the invention

In view of this, main purpose of the present invention is to provide dynamic passive compensation open ring control device and the method thereof in a kind of power supply system, it adopts the reactive power compensation open loop control strategy based on load variations, adjust in real time reactive power compensation circuit three-phase thyristor pilot angle by the situation of change of detection load three-phase current, the purpose of compensating circuit equivalent reactance is adjusted in realization in real time according to load variations, allow each phase reactive power of load system level off to zero, reach the effect of Reactive Power Compensation in real time.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of dynamic passive compensation open ring control device comprises three-phase circuit and load, also comprises the compensating circuit susceptance computing module and No. three compensators that are connected across described load two ends; Wherein:

Described compensator is used for the required lagging reactive power of compensation three-phase electrical power system;

Described compensating circuit susceptance computing module, be used for calculating in real time the required susceptance of compensating circuit according to load three-phase voltage, current data, then utilize interpolation calculation thyristor control angle according to the relation between susceptance amplification coefficient and the thyristor control angle, at last with the pilot angle signal function in compensator, regulate the compensator circuit lagging reactive power.

Wherein, in the described compensator, each branch road compensator is made of two antiparallel thyristors and an inductance.

A kind of control method based on the described dynamic passive compensation open ring control device of claim 1 comprises the steps:

A, make that sample frequency is f _s, sensing lead busbar voltage effective value U (k) measures the current instantaneous value i in the three-phase circuit _La(k), i _Lb(k), i _Lc(k), the line instantaneous voltage u in the measurement three-phase circuit _Ab(k), u _Bc(k), u _Ca(k), wherein k is sampling sequence number;

B, calculate the required susceptance value of three-phase circuit according to the method for calculating the reactive power compensation circuit susceptance based on momentary load electric current, voltage

C, according among the above-mentioned steps B

Calculate each thyristor control angle of three-phase circuit

D, the three-phase line voltage locking phase that obtains according to phase-locked loop are according to the thyristor control angle

The transmitted signal;

E, be back to steps A, carry out the next sampling period and calculate.

Wherein, the required susceptance value of the described three-phase circuit of step B Be respectively:

$B_r^{\mathrm{ab}}=\frac{1}{3\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00002331900300022.png,HDA00002331900300032.png"\; state="\{\{state\}\}">U</figure-callout>}}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}(u_{\mathrm{bc}}{i}_{\mathrm{La}}+u_{\mathrm{ca}}{i}_{\mathrm{Lb}}-u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}$

$B_r^{\mathrm{bc}}=\frac{1}{3\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00002331900300022.png,HDA00002331900300032.png"\; state="\{\{state\}\}">U</figure-callout>}}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}({-u}_{\mathrm{bc}}{i}_{\mathrm{La}}+u_{\mathrm{ca}}{i}_{\mathrm{Lb}}+u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}$

$B_r^{\mathrm{ca}}=\frac{1}{3\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00002331900300022.png,HDA00002331900300032.png"\; state="\{\{state\}\}">U</figure-callout>}}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}(u_{\mathrm{bc}}{i}_{\mathrm{La}}-u_{\mathrm{ca}}{i}_{\mathrm{Lb}}+u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt};$

Wherein: T is the primitive period; U is the load bus voltage effective value; i _La, i _Lb, i _LcBe respectively the current instantaneous value in the three-phase circuit; u _Ab, u _Bc, u _CaBe respectively the line instantaneous voltage in the three-phase circuit.

Here, calculate each thyristor control angle of three-phase circuit

Process be:

Three-phase compensating circuit amplification coefficient calculates according to following formula in C1, elder generation:

$\left\{\begin{array}{c}{K}_{\mathrm{ab}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{ab}}\&times;H}\\ K_{\mathrm{bc}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{bc}}\&times;H};\\ K_{\mathrm{ca}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{ca}}\&times;H}\end{array}\right.$ Wherein: H is every phase reactance;

Be respectively the susceptance value of three-phase circuit;

C2, with above-mentioned result of calculation respectively the substitution thyristor amplify formula

Calculate each thyristor control angle of three-phase circuit

α is the thyristor control angle in the formula.

Dynamic passive compensation open ring control device provided by the present invention and method thereof have the following advantages:

Existing the control of reactive power compensating utilizes identical pilot angle to trigger each thyristor in the three-phase circuit take busbar voltage or reactive power as the control target, although the entire system reactive factor can be adjusted into 1, can not guarantee respectively to balance each other.The reactive power compensation open loop control strategy that the present invention proposes is take the load system negative-sequence current as 0 as target, calculates the three-phase circuit thyristor Trigger Angle of reactive power compensator, not only can improve the system power factor, can also improve system's three-phase imbalance.

Description of drawings

Fig. 1 is the dynamic passive compensation open ring control device principle schematic that the present invention proposes;

Fig. 1 a is the internal circuit configuration figure of each compensator shown in Figure 1;

Fig. 2 is A, B among the embodiment, C three-phase current curve;

Fig. 3 measures the three-phase line voltage curve that obtains among the embodiment;

Fig. 4 is compensating circuit susceptance curve among the embodiment;

Fig. 5 is system's three phase reactive power when not carrying out reactive power compensation among the embodiment;

Fig. 6 is compensating circuit three-phase electricity voltage locking phase among the embodiment;

Fig. 7 be among the embodiment compensating circuit A phase and B mutually between the thyristor triggering impulse signal;

Fig. 8 is the power factor (PF) change curve before and after the system balance among the embodiment;

Fig. 9 is the total reactive power change curve in system balance front and back among the embodiment;

Figure 10 is reactive power change curve before and after A compensates mutually among the embodiment;

Figure 11 is reactive power change curve before and after B compensates mutually among the embodiment;

Figure 12 is reactive power change curve before and after C compensates mutually among the embodiment.

Embodiment

Below in conjunction with accompanying drawing and embodiments of the invention dynamic passive compensation open ring control device of the present invention and method thereof are described in further detail.

Fig. 1 is the dynamic passive compensation open ring control device principle schematic that the present invention proposes.As shown in Figure 1, for utilizing the open ring control device that is formed by reactor, capacitor etc. to carry out the circuit diagram of reactive power compensation in the three-phase ac power system.Mainly comprise three-phase circuit, load (lotus), the compensating circuit susceptance computing module that is connected across described load two ends and No. three compensators.Wherein:

Compensator is used for the required lagging reactive power of compensation three-phase electrical power system, and its each branch road compensator is made of two antiparallel thyristors and an inductance.Its structure as shown in Figure 1a.

Compensating circuit susceptance computing module, be used for calculating in real time the required susceptance of compensating circuit according to load three-phase voltage, current data, then utilize interpolation calculation thyristor control angle according to the relation between susceptance amplification coefficient and the thyristor control angle, at last with the pilot angle signal function in compensator, regulate the compensator circuit lagging reactive power.

In the circuit as shown in Figure 1, A, B, C phase voltage are respectively U _a, U _b, U _c; Y _Lab, Y _Lbc, Y _LcaBe respectively the admittance between admittance between mutually of A phase and B in the load system, B phase and C admittance, C phase and the A phase between mutually; Y _Rab, Y _Rbc, Y _RcaBe respectively the admittance between admittance between mutually of A phase and B in the bucking-out system, B phase and C admittance, C phase and the A phase between mutually, described three-phase voltage satisfies following relational expression:

U is the three-phase voltage effective value in the formula (1), and the reactive power compensation circuit susceptance computing formula that obtains according to symmetrical component method has:

$B_r^{\mathrm{ab}}=-\frac{1}{3U}(\mathrm{Im}{\stackrel{\&CenterDot;}{I}}_{\mathrm{La}}+\mathrm{Imh}{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lb}}-\mathrm{Im}{h}^2{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lc}})$

$B_r^{\mathrm{bc}}=-\frac{1}{3U}(-\mathrm{Im}{\stackrel{\&CenterDot;}{I}}_{\mathrm{La}}+\mathrm{Imh}{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lb}}-\mathrm{Im}{h}^2{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lc}})---\left(2\right)$

$B_r^{\mathrm{ca}}=-\frac{1}{3U}(\mathrm{Im}{\stackrel{\&CenterDot;}{I}}_{\mathrm{La}}+\mathrm{Imh}{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lb}}-\mathrm{Im}{h}^2{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lc}})$

A phase load electric current is in the formula (2)

B phase load electric current is C phase load electric current is

Need to detect load current amplitude and phase place from formula (2) if will calculate as can be known the reactive power compensation circuit susceptance, this need to utilize the method for Fourier transform or wavelet transformation and so on just can obtain for the electric power system that contains harmonic wave, and Fourier transform and wavelet transformation are the signal processing methods of more complicated, need a large amount of calculating to realize.For reducing computation complexity, the present invention then adopts based on the computational methods of electric current, instantaneous voltage and calculates reactive power compensation circuit three-phase susceptance.Specific as follows:

Formula (2) right side molecule denominator be multiply by U simultaneously, and utilize in the formula (1) Between relation, can get following formula:

$B_r^{\mathrm{ab}}=\frac{1}{3U^2}(\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_a{\stackrel{\&CenterDot;}{I}}_{\mathrm{La}}\right)+\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_b{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lb}}\right)-\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_c{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lc}}\right))$

$B_r^{\mathrm{bc}}=\frac{1}{3U^2}(-\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_a{\stackrel{\&CenterDot;}{I}}_{\mathrm{La}}\right)+\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_b{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lb}}\right)-\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_c{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lc}}\right))---\left(3\right)$

$B_r^{\mathrm{ca}}=\frac{1}{3U^2}(\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_a{\stackrel{\&CenterDot;}{I}}_{\mathrm{La}}\right)-\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_b{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lb}}\right)+\mathrm{Im}\left({\stackrel{\&CenterDot;}{U}}_c{\stackrel{\&CenterDot;}{I}}_{\mathrm{Lc}}\right))$

Because the reactive power in the one-period can be calculated according to the following formula:

$\mathrm{Im}\left(\stackrel{\&CenterDot;}{U}\stackrel{\&CenterDot;}{I}\right)=\frac{1}{T}\underset{T}{\&Integral;}u(-\frac{\mathrm{\&pi;}}{2})\mathrm{idt}---\left(4\right)$

Wherein: u, i are vector

Instantaneous value,

Be the voltage fundamental phase shift

Electrical radian, T are the voltage fundamental cycle.

Because

Be not easy to calculate, therefore can process by means of the relation between three-phase line voltage and the phase voltage

According to three-phase alternating current knowledge as can be known:

In conjunction with the principle of formula (3), (4) and (5), compensation susceptance computing formula can be transformed to:

$B_r^{\mathrm{ab}}=\frac{1}{3\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00002331900300022.png,HDA00002331900300032.png"\; state="\{\{state\}\}">U</figure-callout>}}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}(u_{\mathrm{bc}}{i}_{\mathrm{La}}+u_{\mathrm{ca}}{i}_{\mathrm{Lb}}-u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}$

$B_r^{\mathrm{bc}}=\frac{1}{3\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00002331900300022.png,HDA00002331900300032.png"\; state="\{\{state\}\}">U</figure-callout>}}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}({-u}_{\mathrm{bc}}{i}_{\mathrm{La}}+u_{\mathrm{ca}}{i}_{\mathrm{Lb}}+u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}---\left(6\right)$

$B_r^{\mathrm{ca}}=\frac{1}{3\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00002331900300022.png,HDA00002331900300032.png"\; state="\{\{state\}\}">U</figure-callout>}}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}(u_{\mathrm{bc}}{i}_{\mathrm{La}}-u_{\mathrm{ca}}{i}_{\mathrm{Lb}}+u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}$

Wherein: primitive period T=1/f, f are fundamental frequency; U is the load bus voltage effective value; i _La, i _Lb, i _LcBe respectively the current instantaneous value in the three-phase circuit; u _Ab, u _Bc, u _CaBe respectively the line instantaneous voltage in the three-phase circuit.

In sum, utilize formula (6) to calculate the compensating circuit susceptance, only need know that sampling instantaneous voltage, current value carry out integration and get final product, do not need to adopt again the signal processing method of complicated Fourier transform and so on to obtain current amplitude and phase place, therefore greatly reduce amount of calculation, guarantee the application feasibility in the engineering reality.

According to the above analysis, the inventive method is as follows based on the process that momentary load electric current, voltage calculate the reactive power compensation circuit susceptance:

Step 1: make that sample frequency is f _s, sensing lead busbar voltage effective value U (k) (unit: volt), measure the current instantaneous value i in the three-phase circuit _La(k), i _Lb(k), i _Lc(k) (unit: ampere), measure the line instantaneous voltage u in the three-phase circuit _Ab(k), u _Bc(k), u _Ca(k) (unit: volt), wherein k is sampling sequence number;

Step 2: calculate the required susceptance value of three-phase circuit according to the method for calculating the reactive power compensation circuit susceptance based on momentary load electric current, voltage

Step 3: according in the step 2

Calculate each thyristor control angle of three-phase circuit

Step 4: according to the three-phase line voltage locking phase of phase-locked loop acquisition, according to the thyristor control angle

The transmitted signal;

Step 5: be back to step 1, carry out the next sampling period and calculate.

Among Fig. 1, fine rule represents signal data sampling and transmission, and three-phase compensation susceptance calculates link and sends by all means each thyristor control angle as we know from the figure And do not need feedback compensation circuit susceptance whether to reach theoretical equivalent susceptance value.Therefore the open loop control strategy of the present invention's proposition is owing to its simple in structure, convenience of calculation, and less system has good compensation ability for load variations.

For example: be connected to a load system on certain 6.5kV of steel mill bus, establish sample frequency f _s=10000Hz, sampling period T _s=0.0001 _s, actual measurement obtains its three-phase current curve as shown in Figure 2, and the one-period data of three-phase current sampling are as shown in table 1; The three-phase line voltage curve that obtains by actual measurement as shown in Figure 3, an one periodic sampling data are shown in subordinate list 2.

According to the computational methods based on instantaneous voltage, Current calculation compensating circuit susceptance:

$B_r^{\mathrm{ab}}\left(k\right)=\frac{1}{3\sqrt{3}U{\left(k\right)}^2}\&times;\frac{T_s}{T}\underset{k=n}{\overset{n+N}{\mathrm{\&Sigma;}}}{u}_{\mathrm{bc}}\left(k\right)i_{\mathrm{La}}\left(k\right)+u_{\mathrm{ca}}\left(k\right)i_{\mathrm{Lb}}\left(k\right)-u_{\mathrm{ab}}\left(k\right)i_{\mathrm{Lc}}\left(k\right)$

$B_r^{\mathrm{bc}}\left(k\right)=\frac{1}{3\sqrt{3}U{\left(k\right)}^2}\&times;\frac{T_s}{T}\underset{k=n}{\overset{n+N}{\mathrm{\&Sigma;}}}-u_{\mathrm{bc}}\left(k\right)i_{\mathrm{La}}\left(k\right)+u_{\mathrm{ca}}\left(k\right)i_{\mathrm{Lb}}\left(k\right)+u_{\mathrm{ab}}\left(k\right)i_{\mathrm{Lc}}\left(k\right)$

$B_r^{\mathrm{ca}}\left(k\right)=\frac{1}{3\sqrt{3}U{\left(k\right)}^2}\&times;\frac{T_s}{T}\underset{k=n}{\overset{n+N}{\mathrm{\&Sigma;}}}{u}_{\mathrm{bc}}\left(k\right)i_{\mathrm{La}}\left(k\right)-u_{\mathrm{ca}}\left(k\right)i_{\mathrm{Lb}}\left(k\right)+u_{\mathrm{ab}}\left(k\right)i_{\mathrm{Lc}}\left(k\right);$

Wherein: n is any positive integer greater than zero,

Can obtain compensating circuit susceptance curve, as shown in Figure 4, the desirable admittance of compensating circuit three-phase is stabilized in respectively-0.068 west door ,-0.048 west door ,-0.0975 west door through after the iterative computation of one-period.When not carrying out reactive power compensation system's three phase reactive power as shown in Figure 5, three-phase load is all uneven as can be known from accompanying drawing 5, wherein A phase, B be perceptual idle mutually, C is capacitive reactive power mutually.

On above-mentioned desirable three-phase compensating circuit susceptance value basis, next need to calculate each phase thyristor angle of flow, suppose that every phase reactance H selects 0.001H, then three-phase compensating circuit amplification coefficient is respectively:

$\left\{\begin{array}{c}{K}_{\mathrm{ab}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{ab}}\&times;0.001}=46.8103\\ K_{\mathrm{bc}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{bc}}\&times;0.001}=66.3146\\ K_{\mathrm{ca}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{ca}}\&times;0.001}=32.6472\end{array}\right.$

Amplify formula according to thyristor

Wherein α is the thyristor control angle, utilizes cubic spline interpolation can obtain three-phase compensating circuit thyristor control angle and is respectively

The desirable three-phase electricity of bucking-out system keeps constant after being contained in 1 voltage cycle as can be known from Fig. 4, so three-phase circuit thyristor control angle also remains unchanged.

The pulse signal that the triggering thyristor is opened need to produce according to three-phase electricity route voltage-phase and pilot angle, can adopt PHASE-LOCKED LOOP PLL TECHNIQUE to obtain the three-phase line voltage locking phase according to step 4, and accompanying drawing 6 is compensating circuit three-phase line voltage locking phase, wherein

Keep 120 degree phase difference operations, when

The time, produce the forward thyristor pulse triggering signal between A phase and the B phase, thyristor T _AbpConducting, when

The time, produce the reverse thyristor pulse triggering signal between A phase and the B phase, thyristor T _AbnConducting; When The time, produce the forward thyristor pulse triggering signal between B phase and the C phase, thyristor T _BcpConducting, when

The time, produce the reverse thyristor pulse triggering signal between B phase and the C phase, thyristor T _BcnConducting; When

The time, produce the forward thyristor pulse triggering signal between C phase and the A phase, thyristor T _CapConducting, when

The time, produce the reverse thyristor pulse triggering signal between C phase and the A phase, thyristor T _CanConducting.Accompanying drawing 7 has been described A phase and the B thyristor generating positive and negative voltage half period pulse signal between mutually, and as we know from the figure A phase and B one group of in turn conducting of thyristor between has mutually guaranteed the positive and negative checker of reactor current between A phase and the B phase.

After utilizing above-mentioned reactive power compensation open loop control strategy, load system and compensating circuit combine so that on the bus power factor (PF) be improved, accompanying drawing 8 is the power factor (PF) after compensating, and has improved 0.06 before power factor (PF) compensates after the compensation as we know from the figure, and power factor (PF) is almost near 1.The total reactive power of system changes as shown in Figure 9 after the compensation, and total reactive power is close to 0 after finding to compensate from figure.Although total reactive power reduces, but each phase reactive power all is not reduced to zero fully, accompanying drawing 10-12 for compensation after each phase reactive power, open-loop compensation each phase control angle that has been given can not well be controlled for the actual reactive power that reaches as can be known from Figure.

Sampling period tables of data of table 1 three-phase current

Table 2 three-phase line voltage one-period sampling data table

The above is preferred embodiment of the present invention only, is not for limiting protection scope of the present invention.

Claims (5)

1. a dynamic passive compensation open ring control device comprises three-phase circuit and load, it is characterized in that, also comprises the compensating circuit susceptance computing module and No. three compensators that are connected across described load two ends; Wherein:

Described compensator is used for the required lagging reactive power of compensation three-phase electrical power system;

Described compensating circuit susceptance computing module, be used for calculating in real time the required susceptance of compensating circuit according to load three-phase voltage, current data, then utilize interpolation calculation thyristor control angle according to the relation between susceptance amplification coefficient and the thyristor control angle, at last with the pilot angle signal function in compensator, regulate the compensator circuit lagging reactive power.

2. dynamic passive compensation open ring control device according to claim 1 is characterized in that, in the described compensator, each branch road compensator is made of two antiparallel thyristors and an inductance.

3. the control method based on the described dynamic passive compensation open ring control device of claim 1 is characterized in that, comprises the steps:

A, make that sample frequency is f _s, sensing lead busbar voltage effective value U (k) measures the current instantaneous value i in the three-phase circuit _La(k), i _Lb(k), i _Lc(k), the line instantaneous voltage u in the measurement three-phase circuit _Ab(k), u _Bc(k), u _Ca(k), wherein k is sampling sequence number;

B, calculate the required susceptance value of three-phase circuit according to the method for calculating the reactive power compensation circuit susceptance based on momentary load electric current, voltage

C, according among the above-mentioned steps B

Calculate each thyristor control angle of three-phase circuit

D, the three-phase line voltage locking phase that obtains according to phase-locked loop are according to the thyristor control angle

The transmitted signal;

E, be back to steps A, carry out the next sampling period and calculate.

4. the control method of dynamic passive compensation open ring control device according to claim 3 is characterized in that, the required susceptance value of the described three-phase circuit of step B

Be respectively:

$B_r^{\mathrm{ab}}=\frac{1}{3\sqrt{3}{U}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}(u_{\mathrm{bc}}{i}_{\mathrm{La}}+u_{\mathrm{ca}}{i}_{\mathrm{Lb}}-u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}$

$B_r^{\mathrm{bc}}=\frac{1}{3\sqrt{3}{U}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}({-u}_{\mathrm{bc}}{i}_{\mathrm{La}}+u_{\mathrm{ca}}{i}_{\mathrm{Lb}}+u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt}$

$B_r^{\mathrm{ca}}=\frac{1}{3\sqrt{3}{U}^2}\&times;\frac{1}{T}\underset{T}{\&Integral;}(u_{\mathrm{bc}}{i}_{\mathrm{La}}-u_{\mathrm{ca}}{i}_{\mathrm{Lb}}+u_{\mathrm{ab}}{i}_{\mathrm{Lc}})\mathrm{dt};$

Wherein: T is the primitive period; U is the load bus voltage effective value; i _La, i _Lb, i _LcBe respectively the current instantaneous value in the three-phase circuit; u _Ab, u _Bc, u _CaBe respectively the line instantaneous voltage in the three-phase circuit.

5. the control method of dynamic passive compensation open ring control device according to claim 4 is characterized in that, calculates each thyristor control angle of three-phase circuit

Process be:

Three-phase compensating circuit amplification coefficient calculates according to following formula in C1, elder generation:

$\left\{\begin{array}{c}{K}_{\mathrm{ab}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{ab}}\&times;H}\\ K_{\mathrm{bc}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{bc}}\&times;H};\\ K_{\mathrm{ca}}=-\frac{1}{2\mathrm{\&pi;}{\mathrm{fB}}_r^{\mathrm{ca}}\&times;H}\end{array}\right.$ Wherein: H is every phase reactance;

Be respectively the susceptance value of three-phase circuit;

C2, with above-mentioned result of calculation respectively the substitution thyristor amplify formula

Calculate each thyristor control angle of three-phase circuit

α is the thyristor control angle in the formula.

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