CN102801160B - Dynamic trend controller based on voltage magnitude and phase angle control and control method thereof - Google Patents

Abstract

The invention relates to a dynamic trend controller based on voltage magnitude and phase angle control and a control method thereof. The dynamic trend controller comprises a controllable three-phase transformer, a first power unit, a second power unit, a measurement and control module, a series winding unit, an input voltage transformer, an output voltage transformer and an output current transformer, wherein a secondary winding of the controllable three-phase transformer comprises a man joint, a positive tap joint and a negative tap joint, and each phase respectively outputs 2 groups of independent windings with the transformation ratio of N, wherein N is greater than 0 and smaller than 0.2; and the series winding unit of each phase comprises another two phases of the controllable three-phase transformer and each 1 group of independent windings with opposite voltage polarities connected in series. In the invention, the decoupling control of active power and reactive power is realized, the dynamic regulation capability and the power transmission capacity of the power system trend are increased, the stability, the reliability and the like of the system are improved, and the dynamic trend controller has the characteristics of low cost, independent control of active power and reactive power and high reliability.

Description

Based on dynamic power flow controller and the control method thereof of voltage magnitude and phase angle control

Technical field

The present invention relates to flexible transmission technical field, particularly a kind of dynamic power flow controller and control method thereof based on voltage magnitude and phase angle control.

Background technology

Along with the access of intermittent new forms of energy and the uses of various new equipments such as interconnected, the wind-powered electricity generations of large-scale power system, operation of power networks is greatly increased in the possibility at stability limit edge.Therefore, the flexibility of operation of power networks, trend controllability and grid stability seem and become more and more important, and are also the targets that intelligent grid is pursued simultaneously.And in the day by day complicated electrical network of a structure, the voltage and current of control circuit will become the key of problem simultaneously.

For the voltage and current of control circuit, conventional way is to calculate and state estimation is adjusted the excitation of generator by the optimal load flow of off-line, and load tap changer and reactive power compensator meet the double constraints of voltage and current.But in a complicated network, this is a very challenging problem, to such an extent as to can control in real time a complex network without any controller in practice.

There is some new methods amplitude and phase place of the node voltage of control circuit simultaneously, realize the control to active power and reactive power by the control to node voltage phase place and amplitude.Can provide the device of such function to have FACTS equipment, such as THE UPFC (united power flow control, UPFC) and Static Series Synchronous Compensator (static synchronous series compensator, SSSC).Reactive power compensator as SVC and STATCOM can be by reactive power support control node voltage amplitude.Although FACTS device has entered the shaping phase, the economy of said apparatus still has to be tested.Phase shifter can provide power flow control, but can not control voltage, and this control is slow.Solid-state transformer, is called again electric power electric transformer, can control amplitude and the phase angle of voltage, but need to use a large amount of high-power electric and electronic switching devices, and research and development still rest on theoretical research stage.For above problem, someone has proposed controllable network transformer (controllable network transformer, CNT) cheaply, and its required electric power electronic switch capacity is the sub-fraction of transformer capacity.It can control amplitude and the phase angle of output voltage, but smaller and voltage magnitude and phase angle control can not realize decoupling zero to the control range of voltage phase angle, and the low-frequency harmonics producing in order to eliminate the method in addition, needs to increase larger cost.

But also there is significant limitation in current FACTS technology: FACTS unit engineering cost is high, applies difficulty; Between FACTS device and power equipment and other controllers, there is ill-effect; The loss of FACTS device self is large; Complex control structure and the requirement to corresponding auxiliary devices such as communications facilitys of FACTS device, proposed more strict requirement to the operation and control of electrical network; The additional problem that plant failure is brought; Stability of a system problem that series connection access causes etc. is very restricted its application in electrical network.

Summary of the invention

For the problems referred to above, the object of this invention is to provide dynamic power flow controller and the control method thereof of the controlled three-phase transformer of independently controlling based on voltage magnitude and phase angle, the controlled three-phase transformer of this dynamic power flow controller based on full-control type power electronic switch, independence by controlled three-phase transformer output voltage phase angle and amplitude is controlled the decoupling zero control that realizes transmission line active power and reactive power, has low cost, high reliability feature.

Technical solution of the present invention is as follows:

Based on a dynamic power flow controller for voltage magnitude and phase angle control, it is characterized in that this dynamic power flow controller comprises: controlled three-phase transformer, the first power cell, the second power cell, measurement form with control module, the winding element of connecting, input voltage instrument transformer, output voltage instrument transformer and output current transformer:

The secondary of described controlled three-phase transformer comprise major joint, plus tapping head, minus tapping head,, and every phase is exported the independent winding that 2 groups of no-load voltage ratios are N, wherein 0<N<0.2 separately;

The series connection winding element of every phase is formed by other two-phase and the contrary each 1 group of independent winding serial connection of polarity of voltage of controlled three-phase transformer;

The first described power cell is made up of the first switching power tube, second switch power tube, first filter inductance the first filter capacitor and the second filter capacitor;

The second described power cell is made up of the 3rd switching power tube, the 3rd switching power tube, the second filter inductance the 3rd filter capacitor and the 4th filter capacitor;

Described the first switching power tube, second switch power tube, the 3rd switching power tube and the 4th switching power tube form by 2 insulated gate bipolar transistor differential concatenations;

The plus tapping head of the controlled three-phase transformer secondary described in one termination of the first described switching power tube, one termination minus tapping head of described second switch power tube, the other end of this first group of switching power tube is connected with the other end of second group of switching power tube and this tie point is connected with one end of described the first filter inductance, the other end of this first filter inductance respectively with one end of the described winding element of connecting, one end of the 4th switching power tube, one end of the second filter capacitor is connected, the other end of the second filter capacitor is connected with the secondary major joint of described controlled three-phase transformer, the other end of described series connection winding element is connected with one end of the 3rd switching power tube, the 3rd described switching power tube other end is connected with the 4th switching power tube other end and this tie point is connected with one end of described the second filter inductance, the other end of this second filter inductance connects out-put supply or load,

The first described filter capacitor is connected between the plus tapping head and minus tapping head of described controlled three-phase transformer secondary, the 3rd described filter capacitor is connected across between the 3rd switching power tube and the 4th disjunct two ends of switching power tube, one end of the 4th described filter capacitor is connected with the tie point of 2 serial connection windings in series connection winding element, the other end of the 4th filter capacitor connects out-put supply or load end

One side of described input voltage instrument transformer is connected with the former limit of controlled three-phase transformer input voltage main circuit, and voltage signal output end is connected with the voltage signal input port of control module with described measurement;

Described output voltage instrument transformer, a side is connected with controlled three-phase transformer secondary output voltage main circuit, and voltage signal output end is connected with the voltage signal input port of control module with described measurement;

Described output current transformer, is serially connected in the output main circuit of controlled three-phase transformer, and its current signal output end is connected with the current signal input port of control module with described measurement;

Described measurement is connected with the control end of the 4th switching power tube with described the first switching power tube second switch power tube, the 3rd switching power tube respectively with the control signal output of control module, and this measurement is connected with host computer with control module.

Described measurement and control module are digital signal processor, single-chip microcomputer or computer.

Utilize described dynamic power flow controller to carry out the control method of output voltage amplitude, phase angle, its feature is that the method comprises following concrete steps:

1) establish the positive and negative tap no-load voltage ratio of controlled three-phase transformer and be respectively (1+N) and (1-N), controlled three-phase transformer three-phase input voltage is respectively:

V _ain=sin(ω ₀t)

V _bim=sin(ω ₀t+120°) (1)

V _cin=sin(ω ₀t-120°)

Wherein, V _ainfor A phase input voltage, V _binfor B phase input voltage, V _cinfor C phase input voltage;

2) by pulse-width modulation, the duty ratio of the first switching power tube, second switch power tube, the 3rd switching power tube and the 4th switching power tube is regulated:

If the duty ratio of the first switching power tube and second switch power tube is D ₁, the duty ratio of establishing the 3rd switching power tube and the 4th switching power tube is D ₂, wherein, 0≤D ₁≤ 1,0≤D ₂≤ 1;

Work as D ₁=1 o'clock, S ₁conducting, S ₂turn-off, work as D ₁=0 o'clock, S ₂conducting, S ₁turn-off; Work as D ₂=1 o'clock, S ₃conducting, S ₄turn-off, work as D ₂=0 o'clock, S ₄conducting, S ₃turn-off;

3) calculate A phase output voltage, formula is as follows:

V _aout=V _ain[(1+N)D ₁+(1-N)(1-D ₁)] (2)

+(NV _bin-NV _cin)D ₂

4) by V in step 1) _ain, V _bin, V _cinsubstitution formula (2) obtains:

$V_{\mathrm{aout}}=[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]\sin \left({\mathrm{\&omega;}}_{0}t\right)$ $\left(3\right)$

$+\sqrt{3}N{D}_2\cos \left({\mathrm{\&omega;}}_{0}t\right)$

5) output voltage amplitude is:

$A=\sqrt{{[(1+N)D_1+(1-N)(1-D_1)]}^2+{\left(\sqrt{3}N{D}_2\right)}^2}---\left(4\right)$

6) output voltage phase shift angle θ is:

$\mathrm{\&theta;}={\tan }^{-1}\left(\frac{\sqrt{3}N{D}_2}{[(1+N)D_1+(1-N)(1-D_1)]}\right)---\left(5\right)$

By changing duty ratio D ₁and D ₂can change amplitude and the phase angle of output voltage.Conventionally N<0.2, therefore, amplitude regulates and depends primarily on D ₁, phase angle regulates and depends primarily on D ₂.

In the time of N=0.1, approximate can obtaining, voltage magnitude control range is:

0.9≤A≤1.1 (6)

Voltage phase angle control range is:

7) described dynamic power flow controller is serially connected between two electrical networks, input termination first electrical network (11) of dynamic power flow controller, the output of this dynamic power flow controller is connected with the second electrical network (21) through outlet line, transmits electricity to the second electrical network (21) by this dynamic power flow controller and transmission line;

8) the transmission line reactance of establishing between the output of dynamic power flow controller and electrical network 2 is J ω L;

9) the active-power P of dynamic power flow controller transmission and the relation of reactive power Q and dynamic power flow controller output voltage phase shift angle θ are as follows:

$P=\frac{V_{2}A{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">V</figure-callout>}}_1}{\mathrm{\&omega;L}}\sin (\mathrm{\&delta;}+\mathrm{\&theta;})---\left(8\right)$

$Q=\frac{V_2^2-V_{2}A{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">V</figure-callout>}}_1\cos (\mathrm{\&delta;}+\mathrm{\&theta;})}{\mathrm{\&omega;L}}---\left(9\right)$

Wherein V ₁and V ₂be respectively the voltage magnitude of the first electrical network and the second electrical network, δ is V ₂with V ₁differential seat angle.

From formula (8), (9), can find out, active-power P is main relevant with controlled three-phase transformer output voltage θ, reactive power Q is main relevant with controlled three-phase transformer output voltage amplitude A, and the active-power P of controlled three-phase transformer output mainly and duty ratio D ₂relevant, reactive power Q is main and duty ratio D ₁relevant;

Therefore, by duty ratio D ₁, D ₂adjusting realized the adjusting of dynamic power flow controller active power of output and reactive power.Because the tap conducting to controlled three-phase transformer is controlled, control switch power tube IGBT capacity is only a part for controlled three-phase transformer capacity, thereby cost is low, thus the control of the dynamic power flow of the low cost of realization, high reliability.

Compared with prior art, feature of the present invention is as follows:

1. switching power tube only need be controlled the conducting of controlled three-phase transformer tap, thereby cost is low, has overcome the expensive problem of existing FACTS device;

2. control by the independence of dynamic power flow controller output voltage phase angle and amplitude the decoupling zero control that realizes transmission line active power and reactive power;

3. output voltage does not contain low-order harmonic, quality is good.

Accompanying drawing explanation

Fig. 1 is that the dynamic power flow controller that the present invention is based on voltage magnitude and phase angle control is serially connected in 2 connection layouts in electrical network.

Fig. 2 is the structural representation that the present invention is based on the dynamic power flow controller of voltage magnitude and phase angle control.

Fig. 3 is the voltage vector schematic diagram that the present invention changes voltage phase angle principle, and wherein a has shown how to obtain the component of voltage perpendicular with A by B, C two phase voltages; B is that output voltage vector adjustable range is as shown in dotted line frame in figure.

Fig. 4 is that harmonic wave of output voltage of the present invention is analyzed schematic diagram.In figure, ordinate Mag is voltage magnitude, and abscissa Frequency is frequency.

Fig. 5 is the present invention's electronic power switch device voltage and current waveform analogous diagram while working, and in figure, IGBT is insulated gate transistor, the anti-paralleled diode that Diode is IGBT.

Fig. 6 is input and output voltage waveform schematic diagram of the present invention.

Fig. 7 is Reactive Power Control emulation schematic diagram of the present invention, and in figure, Q is reactive power.

Fig. 8 is active power control emulation schematic diagram of the present invention, and in figure, P is active power.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the invention will be further described, but should not limit the scope of the invention with this.

First refer to Fig. 2, Fig. 2 is the structural representation of dynamic power flow controller of the present invention, as shown in the figure, the controlled three-phase transformer device that voltage magnitude and phase angle are independently controlled, comprising: controlled three-phase transformer 1, the first power cell 2, the second power cell 8, measurement form with control module 3, the winding element 4 of connecting, input voltage instrument transformer 5, output voltage instrument transformer 6 and output current transformer 7:

The secondary of described controlled three-phase transformer 1 comprises major joint 12, plus tapping head 13, minus tapping head 11, and every phase is exported the independent winding that 2 groups of no-load voltage ratios are N, wherein 0<N<0.2 separately;

The series connection winding element 4 of every phase is formed by other two-phase and the contrary each 1 group of independent winding serial connection of polarity of voltage of controlled three-phase transformer 1;

The first described power cell 2 is by the first switching power tube S ₁, second switch power tube S ₂, the first filter inductance L _f1the first filter capacitor C _f1with the second filter capacitor C _fcomposition;

The second described power cell 8 is by the 3rd switching power tube S ₃, the 3rd switching power tube S ₄, the second filter inductance L _f2the 3rd filter capacitor C _f3with the 4th filter capacitor C _f4composition;

The first described switching power tube S ₁, second switch power tube S ₂, the 3rd switching power tube S ₃with the 4th switching power tube S ₄form (not shown) by 2 insulated gate bipolar transistor differential concatenations;

The first described switching power tube S ₁a termination described in the plus tapping head 13 of controlled three-phase transformer 1 secondary, described second switch power tube S ₂a termination minus tapping head 11, this first group of switching power tube S ₁the other end and second group of switching power tube S ₂the other end be connected and this tie point and described the first filter inductance L _f1one end be connected, this first filter inductance L _f2the other end respectively with one end, the 4th switching power tube S of the described winding element 4 of connecting ₄one end, the second filter capacitor C _f2one end be connected, the second filter capacitor C _f2the other end be connected with the secondary major joint 12 of described controlled three-phase transformer 1, the other end of described series connection winding element 4 and the 3rd switching power tube S ₃one end be connected, the 3rd described switching power tube S ₃the other end and the 4th switching power tube S ₄the other end is connected and this tie point and described the second filter inductance L _f2one end be connected, this second filter inductance L _f2the other end connect out-put supply or load,

The first described filter capacitor C _f1be connected between the plus tapping head 13 and minus tapping head 11 of described controlled three-phase transformer 1 secondary the 3rd described filter capacitor C _f3be connected across the 3rd switching power tube S ₃with the 4th switching power tube S ₄between disjunct two ends, the 4th described filter capacitor C _f4one end with series connection winding element 4 in 2 serial connection windings tie points be connected, the 4th filter capacitor C _f4the other end connect out-put supply or load end,

One side of described input voltage instrument transformer 5 is connected with the former limit of controlled three-phase transformer input voltage main circuit, and voltage signal output end is connected with the voltage signal input port of control module 3 with described measurement;

Described output voltage instrument transformer 6, one sides are connected with controlled three-phase transformer secondary output voltage main circuit, and voltage signal output end is connected with the voltage signal input port of control module 3 with described measurement;

Described output current transformer 7, is serially connected in the output main circuit of controlled three-phase transformer, and its current signal output end is connected with the current signal input port of control module 3 with described measurement;

The control signal output of described measurement and control module 3 respectively with described the first switching power tube S ₁second switch power tube S ₂, the 3rd switching power tube S ₃with the 4th switching power tube S ₄control end be connected, this measurement is connected with host computer with control module 3.

Described measurement and control module 3 are digital signal processor, single-chip microcomputer or computer.

Utilize dynamic power flow controller to carry out the control method of output voltage amplitude, phase angle, it is characterized in that the method comprises following concrete steps:

1) establish the positive and negative tap no-load voltage ratio of controlled three-phase transformer and be respectively (1+N) and (1-N), the three-phase input voltage of establishing controlled three-phase transformer is respectively:

V _ain=sin(ω ₀t)

V _bin=sin(ω ₀t+120°) (1)

V _cin=sin(ω ₀t-120°)

2) pass through PWM technology to switch S ₁, S ₂and S ₃, S ₄duty ratio regulate.If S ₁, S ₂duty ratio be D ₁, establish S ₃, S ₄duty ratio be D ₂, 0≤D ₁≤ 1,0≤D ₂≤ 1.Work as D ₁=1 o'clock, S ₁conducting, S ₂turn-off, work as D ₁=0 o'clock, S ₂conducting, S ₁turn-off; Work as D ₂=1 o'clock, S ₃conducting, S ₄turn-off, work as D ₂=0 o'clock, S ₄conducting, S ₃turn-off.

3) can obtain A phase output voltage is:

V _aout=V _ain[(1+N)D ₁+(1-N)(1-D ₁)] (2)

+(NV _bin-NV _cin)D ₂

4) by V _ain, V _bin, V _cinsubstitution obtains:

$V_{\mathrm{aout}}=[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]\sin \left({\mathrm{\&omega;}}_{0}t\right)$ $\left(3\right)$

$+\sqrt{3}N{D}_2\cos \left({\mathrm{\&omega;}}_{0}t\right)$

From above formula, can find out, output voltage, except containing the sinusoidal component consistent with input phase, also contains the cosine component of spending with its phase phasic difference 90.

5) output voltage amplitude is:

$A=\sqrt{{[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]}^2+{\left(\sqrt{3}N{D}_2\right)}^2}---\left(4\right)$

6) output voltage phase shift angle θ is:

$\mathrm{\&theta;}={\tan }^{-1}\left(\frac{\sqrt{3}N{D}_2}{[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]}\right)---\left(5\right)$

In the time of N=0.1, approximate can obtaining, voltage magnitude control range is:

0.9≤A≤1.1 (6)

Voltage phase angle control range is:

By changing duty ratio D ₁and D ₂can change amplitude and the phase angle of output voltage.Conventionally N<0.2, therefore, amplitude regulates and depends primarily on D ₁, phase angle regulates and depends primarily on D ₂.

7) described dynamic power flow controller is serially connected between two electrical networks, input termination first electrical network (11) of dynamic power flow controller, the output of this dynamic power flow controller is connected with the second electrical network 21 through outlet line, transmits electricity to the second electrical network 22 by this dynamic power flow controller and transmission line;

8) the transmission line reactance of establishing between the output of dynamic power flow controller and the second electrical network 22 is j ω L;

9) the active-power P of dynamic power flow controller transmission and the relation of reactive power Q and dynamic power flow controller output voltage phase shift angle θ are as follows:

$P=\frac{V_{2}A{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">V</figure-callout>}}_1}{\mathrm{\&omega;L}}\sin (\mathrm{\&delta;}+\mathrm{\&theta;})---\left(8\right)$

$Q=\frac{V_2^2-V_{2}A{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA00002013109700041.png,HDA00002013109700042.png"\; state="\{\{state\}\}">V</figure-callout>}}_1\cos (\mathrm{\&delta;}+\mathrm{\&theta;})}{\mathrm{\&omega;L}}---\left(9\right)$

Wherein V ₁and V ₂be respectively the voltage magnitude of the first electrical network and the second electrical network, δ is V ₂with V ₁differential seat angle.

From formula (8), (9), can find out, active-power P is main relevant with controlled three-phase transformer output voltage θ, reactive power Q is main relevant with controlled three-phase transformer output voltage amplitude A, and the active-power P of controlled three-phase transformer output mainly and duty ratio D ₂relevant, reactive power Q is main and duty ratio D ₁relevant;

Therefore, by duty ratio D ₁, D ₂adjusting realized the adjusting of dynamic power flow controller active power of output and reactive power.Because the tap conducting to controlled three-phase transformer is controlled, control switch power tube IGBT capacity is only a part for controlled three-phase transformer capacity, thereby cost is low, thus the control of the dynamic power flow of the low cost of realization, high reliability.

Fig. 3 is the phase shift of dynamic power flow controller output voltage and the voltage vector diagram that changes amplitude principle.Fig. 4 is that harmonic wave of output voltage of the present invention is analyzed schematic diagram, can find out, output voltage is not containing low-order harmonic, only containing switching frequency harmonic wave, therefore, easily filtering, because first and second group power cell all contains high-frequency filter circuit, to high-frequency harmonic filtering in addition, thereby make the waveform of the voltage of controlled three-phase transformer outputting high quality.

Fig. 5 is N=0.1, D ₁=0.5, D ₂the controlled three-phase transformer electronic power switch device voltage analogous diagram of=0 o'clock, shows the sub-fraction that electronic power switch device operating voltage is controlled three-phase transformer in figure, 20%(2N doubly).From analogous diagram 6 found out phase shift approximately 11 degree, output amplitude has increased by 10%, consistent with above-mentioned analysis result.

Dynamic power flow control emulation is as follows:

As shown in Figure 3, V1 and V2 amplitude are all 35kV to emulation model used, V ₁compare V ₂leading 20 °.

Keep D ₂=0, D ₁increase by 0.25 from 0 every step and change to 1, the reactive power that circuit transmits changes as shown in Figure 7.

Keep D ₁=0.5, D ₂increase by 0.25 from 0 every step and change to 1, the active power that circuit transmits changes as shown in Figure 8.

Known from above-mentioned simulation result, change modulation parameter D ₁, D ₂, can control dynamically active power and reactive power that dynamic power flow controller is exported.

Claims (3)

1. the dynamic power flow controller based on voltage magnitude and phase angle control, it is characterized in that, this dynamic power flow controller comprises: controlled three-phase transformer (1), the first power cell (2), the second power cell (8), measurement form with control module (3), the winding element of connecting (4), input voltage instrument transformer (5), output voltage instrument transformer (6) and output current transformer (7):

The secondary of described controlled three-phase transformer (1) comprises major joint (12), plus tapping head (13), minus tapping head (11), and every phase is exported the independent winding that 2 groups of no-load voltage ratios are N, wherein 0<N<0.2 separately;

The series connection winding element (4) of every phase is formed by other two-phase and the contrary each 1 group of independent winding serial connection of polarity of voltage of controlled three-phase transformer (1);

Described the first power cell (2) is by the first switching power tube (S ₁), second switch power tube (S ₂), the first filter inductance (L _f1), the first filter capacitor (C _f1) and the second filter capacitor (C _f2) composition;

Described the second power cell (8) is by the 3rd switching power tube (S ₃), the 4th switching power tube (S ₄), the second filter inductance (L _f2), the 3rd filter capacitor (C _f3) and the 4th filter capacitor (C _f4) composition;

The first described switching power tube (S ₁), second switch power tube (S ₂), the 3rd switching power tube (S ₃) and the 4th switching power tube (S ₄) form by 2 insulated gate bipolar transistor differential concatenations;

The first described switching power tube (S ₁) a termination described in the plus tapping head (13) of controlled three-phase transformer (1) secondary, described second switch power tube (S ₂) a termination minus tapping head (11), this first switching power tube (S ₁) the other end and second switch power tube (S ₂) the other end be connected and tie point and described the first filter inductance (L _f1) one end be connected, this first filter inductance (L _f1) the other end respectively with one end, the 4th switching power tube (S of the described winding element of connecting (4) ₄) one end, the second filter capacitor (C _f2) one end be connected, the second filter capacitor (C _f2) the other end be connected with the secondary major joint (12) of described controlled three-phase transformer (1), the other end of described series connection winding element (4) and the 3rd switching power tube (S ₃) one end be connected, the 3rd described switching power tube (S ₃) other end and the 4th switching power tube (S ₄) other end is connected and this tie point and described the second filter inductance (L _f2) one end be connected, this second filter inductance (L _f2) the other end connect out-put supply or load,

The first described filter capacitor (C _f1) be connected between the plus tapping head (13) and minus tapping head (11) of described controlled three-phase transformer (1) secondary the 3rd described filter capacitor (C _f3) be connected across the 3rd switching power tube (S ₃) and the 4th switching power tube (S ₄) between disjunct two ends, the 4th described filter capacitor (C _f4) one end be connected with the tie points of 2 serial connection windings in series connection winding element (4), the 4th filter capacitor (C _f4) the other end connect out-put supply or load end,

One side of described input voltage instrument transformer (5) is connected with the former limit of controlled three-phase transformer input voltage main circuit, and voltage signal output end is connected with the voltage signal input port of control module (3) with described measurement;

Described output voltage instrument transformer (6), a side is connected with controlled three-phase transformer secondary output voltage main circuit, and voltage signal output end is connected with the voltage signal input port of control module (3) with described measurement;

Described output current transformer (7), is serially connected in the output main circuit of controlled three-phase transformer, and its current signal output end is connected with the current signal input port of control module (3) with described measurement;

The control signal output of described measurement and control module (3) respectively with described the first switching power tube (S ₁), second switch power tube (S ₂), the 3rd switching power tube (S ₃) and the 4th switching power tube (S ₄) control end be connected, this measurement is connected with host computer with control module (3).

2. dynamic power flow controller according to claim 1, is characterized in that described measurement and control module (3) are digital signal processor, single-chip microcomputer or computer.

3. the method for utilizing the dynamic power flow controller described in claim 1 to carry out output voltage amplitude and phase angle control, is characterized in that, the method comprises following concrete steps:

1) establish the positive and negative tap no-load voltage ratio of controlled three-phase transformer and be respectively (1+N) and (1-N), controlled three-phase transformer three-phase input voltage is respectively:

V _ain＝sin(ω ₀t)

V _bin＝sin(ω ₀t+120°) (1)

V _cin＝sin(ω ₀t-120°)

Wherein, V _ainfor A phase input voltage, V _binfor B phase input voltage, V _cinfor C phase input voltage;

2) by pulse-width modulation, the duty ratio of the first switching power tube, second switch power tube, the 3rd switching power tube and the 4th switching power tube is regulated:

If the duty ratio of the first switching power tube and second switch power tube is D ₁, the duty ratio of establishing the 3rd switching power tube and the 4th switching power tube is D ₂, wherein, 0≤D ₁≤ 1,0≤D ₂≤ 1;

3) calculate A phase output voltage, formula is as follows:

V _aout＝V _ain[(1+N)D ₁+(1-N)(1-D ₁)] (2)

+(NV _bin-NV _cin)D ₂

4) by V in step 1) _ain, V _bin, V _cinsubstitution formula (2) obtains:

$\begin{array}{c}{V}_{\mathrm{aout}}=[(1+N)D_1+(1-N)(1-D_1)]\sin \left({\mathrm{\&omega;}}_{0}t\right)\\ +\sqrt{3}{\mathrm{ND}}_2\cos \left({\mathrm{\&omega;}}_{0}t\right)\end{array}---\left(3\right)$

5) output voltage amplitude is:

$A=\sqrt{{[(1+N)D_1+(1-N)(1-D_1)]}^2+{\left(\sqrt{3}{\mathrm{ND}}_2\right)}^2}---\left(4\right)$

6) output voltage phase shift angle θ is:

$\mathrm{\&theta;}={\tan }^{-1}\left(\frac{\sqrt{3}{\mathrm{ND}}_2}{[(1+N)D_1+(1-N)(1-D_1)]}\right)---\left(5\right)$

7) described dynamic power flow controller is serially connected between two electrical networks, input termination first electrical network (11) of dynamic power flow controller, the output of this dynamic power flow controller is connected with the second electrical network (21) through outlet line, transmits electricity to the second electrical network (22) by this dynamic power flow controller and transmission line;

8) the transmission line reactance of establishing between output and second electrical network of dynamic power flow controller is j ω L;

9) the active-power P of dynamic power flow controller transmission and the relation of reactive power Q and dynamic power flow controller output voltage phase shift angle θ are as follows:

$P=\frac{V_{2}A{V}_1}{\mathrm{\&omega;L}}\sin (\mathrm{\&delta;}+\mathrm{\&theta;})---\left(8\right)$

$Q=\frac{V_2^2-V_{2}A{V}_1\cos (\mathrm{\&delta;}+\mathrm{\&theta;})}{\mathrm{\&omega;L}}---\left(9\right)$

Wherein V ₁and V ₂be respectively the voltage magnitude of the first electrical network and the second electrical network, δ is V ₂with V ₁differential seat angle.

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