CN102801381A - Controllable transformer device capable of controlling amplitude and phase angle of voltage individually and control method for same - Google Patents

Abstract

The invention discloses a controllable transformer device capable of controlling amplitude and phase angle of voltage individually and a control method for the same. The controllable transformer device consists of a controllable three-phase transformer, a power unit, a measuring and control module, a series winding unit and an input voltage transformer, wherein the secondary side of the controllable three-phase transformer comprises a main terminal, a positive tapping point and a negative tapping point, and two groups of independent windings with a ratio of transformation of N respectively output by each phase; and the series winding unit of each phase is formed by connecting an independent winding with opposite voltage polarities of each of the other two phases of the controllable three-phase transformer in series. Due to the adoption of the controllable transformer device and the control method, the amplitude and phase angle of the output voltage of the controllable transformer are controlled individually, the dynamic regulation capability and transmission capability for the load flow of a power system are improved, the stability and reliability of the system are improved, and the controllable transformer device has the characteristics of low cost, capability of individually controlling the amplitude and phase angle of the voltage, and high reliability.

Description

Controllable transformer device and control method thereof that voltage magnitude and phase angle are independently controlled

Technical field

The present invention relates to the flexible transmission technical field, particularly a kind of controllable transformer device and control method of independently controlling based on voltage magnitude and phase angle thereof.

Background technology

Along with the access of intermittent new forms of energy such as interconnected, the wind-powered electricity generation of large-scale power system and the use of various new equipments, make operation of power networks greatly increase 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 also are the targets that intelligent grid is pursued simultaneously.And in the complicated day by day electrical network of a structure, the voltage and current of control circuit will become key of problem simultaneously.

For the voltage and current of control circuit, conventional way is that the optimal load flow through off-line calculates and state estimation is adjusted the excitation of generator, and load tap changer and reactive power compensator satisfy the double constraints of voltage and current.But in the network of a complicacy, this is a very challenging problem, to such an extent as to have no controller can control a complex network in real time in practice.

Some new methods amplitude and the phase place of the node voltage of control circuit are simultaneously arranged, realize control active power and reactive power through control to node voltage phase place and amplitude.Can provide the device of such function that FACTS equipment is arranged, such as THE UPFC (united power flow control, UPFC) and SSSC (static synchronous series compensator, SSSC).Reactive power compensator such as SVC and STATCOM can be through idle support Control Node voltage magnitudes.Although the FACTS device has got into the shaping phase, the economy of said apparatus still has to be waited to check.Phase shifter can provide power flow control, but can not control voltage, and this control is slow.Solid-state transformer is called electric power electric transformer again, can control the amplitude and the phase angle of voltage, but needs to use a large amount of high-power electric and electronic switching devices, and research and development still rest on theoretical research stage.To above problem, the someone has proposed cheaply the controllable network transformer, and (controllable network transformer, CNT), its required electric power electronic switch capacity is the sub-fraction of transformer capacity.It can control output voltage amplitude and phase angle, but to the control range of voltage phase angle smaller and voltage magnitude control can not realize decoupling zero with phase angle, in addition in order to eliminate the low-frequency harmonics that this method produces, need the bigger cost of increase.

But also there is significant limitation in present FACTS technology: FACTS unit engineering cost is high, applies difficulty; There is ill-effect between FACTS device and power equipment and other controllers; The loss of FACTS device self is big; The complicated control structure of FACTS device and to the requirement of corresponding auxiliary devices such as communications facility has proposed more strict requirement to the operation and the control of electrical network; The additional problem that plant failure is brought; Stability of a system problem that the series connection access causes or the like makes its application in electrical network receive very big restriction.

Summary of the invention

To the problems referred to above; The purpose of this invention is to provide controllable transformer device and control method thereof that a kind of voltage magnitude and phase angle are independently controlled; This device is based on the controlled three-phase transformer of full-control type power electronic switch; Realize the independent control of controllable transformer output voltage amplitude and phase angle, have low cost, high reliability characteristics.

Technical solution of the present invention is following:

The controllable transformer device that a kind of voltage magnitude and phase angle are independently controlled is characterized in that this device comprises: controlled three-phase transformer, first power cell, second power cell, measurement constitute with control module, the winding element of connecting, input voltage instrument transformer and output voltage instrument transformer:

Described controlled three-phase transformer secondary comprises major joint, plus tapping head, minus tapping head, and every phase independent winding that to export 2 groups of no-load voltage ratios separately be N, and wherein 0 < N < 0.2;

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

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

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

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

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

Described first filter capacitor is connected between the plus tapping head and minus tapping head of described controlled three-phase transformer secondary; Described the 3rd filter capacitor is connected across between the 3rd switching power tube and the disjunct two ends of the 4th switching power tube; One end of described the 4th filter capacitor links to each other with the tie point of 2 serial connection windings in the 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 links to each other with the former limit of controlled three-phase transformer input voltage main circuit, and voltage signal output end links to each other with the voltage signal input port of control module with described measurement;

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

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

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

The controllable transformer device that utilizes described voltage magnitude and phase angle independently to control carries out the method for output voltage amplitude and phase angle control, it is characterized in that this 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 _AinBe A phase input voltage, V _BinBe B phase input voltage, V _CinBe C phase input voltage;

2) through pulse-width modulation the duty ratio of 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 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 following:

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

+(NV _bin-NV _cin)D ₂

4) with V in the step 1) _Ain, V _Bin, V _CinSubstitution formula (2) obtains:

$V_{\mathrm{aout}}=[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013105000031.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]\sin \left({\mathrm{\&omega;}}_{0}t\right)$ (3)

$+\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="ND"\; filenames="HDA00002013105000031.png,HDA00002013105000032.png"\; state="\{\{state\}\}">ND</figure-callout>}}_2\cos \left({\mathrm{\&omega;}}_{0}t\right)$

5) output voltage amplitude is:

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

6) output voltage phase shift angle θ is:

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

Through changing duty ratio D ₁And D ₂Can change output voltage amplitude and phase angle.Common N<0.2 therefore, amplitude is regulated and is depended primarily on D ₁, phase angle is regulated and is depended primarily on D ₂

When N=0.1, then approximate can getting, the voltage magnitude control range is:

0.9≤A≤1.1 (6)

The voltage phase angle control range is:

Principle of the present invention: can realize independent control to controllable transformer output voltage amplitude and phase angle through adjusting to the pulse-width modulation of insulated gate transistor IGBT; Because the tap conducting of controlled three-phase transformer is controlled; The switching power tube IGBT capacity of controlling controlled three-phase transformer tap is merely the part of controlled three-phase transformer capacity; Thereby; Cost is low, thus the independent control of the voltage magnitude of the low cost of realization, high reliability and phase angle.

Compared with prior art, characteristics of the present invention are following:

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

2. realized the independent control of controllable transformer output voltage amplitude and phase angle;

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

Description of drawings

Fig. 1 is the structural representation of the controllable transformer device independently controlled of voltage magnitude of the present invention and phase angle.

Fig. 2 is the voltage vector sketch map that the present invention changes the voltage phase angle principle, and wherein a has showed how to obtain the component of voltage perpendicular with A by B, C two phase voltages; B is the output voltage vector adjustable range as shown in the frame of broken lines among the figure.

Fig. 3 is that harmonic wave of output voltage of the present invention is analyzed sketch map.Ordinate Mag is a voltage magnitude among the figure, and abscissa Frequency is a frequency.

Fig. 4 is the present invention's electronic power switch device voltage and current waveform analogous diagram when working, and IGBT is an insulated gate transistor among the figure, and Diode is the inverse parallel diode of IGBT.

Fig. 5 is a controllable transformer device dynamic response sketch map of the present invention.

Fig. 6 is an input and output voltage waveform sketch map of the present invention.

Embodiment

Below in conjunction with embodiment and accompanying drawing the present invention is described further, but should limit protection scope of the present invention with this.

See also Fig. 1 earlier, Fig. 1 is the structural representation of the controllable transformer device independently controlled of a kind of voltage magnitude of the present invention and phase angle.Visible by figure; The controllable transformer device that a kind of voltage magnitude and phase angle are independently controlled comprises: controlled three-phase transformer 1, first power cell 2, second power cell 8, measurement and control module 3, the winding element 4 of connecting, input voltage instrument transformer 5 and output voltage instrument transformer 6 constitute:

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

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

Described first 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 _fForm;

Described second 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 _F4Form;

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

The described first switching power tube S ₁The plus tapping head 13 of described controlled three-phase transformer 1 secondary of a termination, 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 link to each other and this tie point and the described first filter inductance L _F1An end link to each other this first filter inductance L _F1The other end respectively with an end, the 4th switching power tube S of the described winding element 4 of connecting ₄An end, the second filter capacitor C _F2An end link to each other the second filter capacitor C _F2The other end link to each other the other end of described series connection winding element 4 and the 3rd switching power tube S with the secondary major joint 12 of described controlled three-phase transformer 1 ₃An end link to each other described the 3rd switching power tube S ₃The other end and the 4th switching power tube S ₄The other end links to each other and this tie point and the described second filter inductance L _F2An end link to each other this second filter inductance L _F2The other end connect out-put supply or load,

The described first filter capacitor C _F1Be connected between the plus tapping head 13 and minus tapping head 11 of described controlled three-phase transformer 1 secondary described the 3rd filter capacitor C _F3Be connected across the 3rd switching power tube S ₃With the 4th switching power tube S ₄Between the disjunct two ends, described the 4th filter capacitor C _F4An end with the series connection winding element 4 in 2 the serial connection windings tie points link to each other the 4th filter capacitor C _F4The other end connect out-put supply or load end,

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

One side of described output voltage instrument transformer 6 links to each other with controlled three-phase transformer secondary output voltage main circuit, and voltage signal output end links to each other with the voltage signal input port of control module 3 with described measurement;

The control signal output ends of described measurement and control module 3 respectively with the described 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 link to each other, this measurement links to each other with host computer with control module 3.

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

The controllable transformer device that utilizes described voltage magnitude and phase angle independently to control carries out the method for output voltage amplitude and phase angle control, and this 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 _AinBe A phase input voltage, V _BinBe B phase input voltage, V _CinBe C phase input voltage;

2) through pulse-width modulation the duty ratio of 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 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 following:

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

+(NV _bin-NV _cin)D ₂

4) with V in the step 1) _Ain, V _Bin, V _CinSubstitution formula (2) obtains:

$V_{\mathrm{aout}}=[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013105000031.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]\sin \left({\mathrm{\&omega;}}_{0}t\right)$ (3)

$+\sqrt{3}{\mathrm{<figure-callout\; id="2"\; label="ND"\; filenames="HDA00002013105000031.png,HDA00002013105000032.png"\; state="\{\{state\}\}">ND</figure-callout>}}_2\cos \left({\mathrm{\&omega;}}_{0}t\right)$

5) output voltage amplitude is:

$A=\sqrt{{[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013105000031.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]}^2+{\left(\sqrt{3}{\mathrm{ND}}_2\right)}^2}---\left(4\right)$

6) output voltage phase shift angle θ is:

$\mathrm{\&theta;}={\tan }^{-1}\left(\frac{\sqrt{3}{\mathrm{ND}}_2}{[(1+N){\mathrm{<figure-callout\; id="1"\; label="D"\; filenames="HDA00002013105000031.png"\; state="\{\{state\}\}">D</figure-callout>}}_1+(1-N)(1-D_1)]}\right)---\left(5\right)$

When N=0.1, then approximate can getting, the voltage magnitude control range is:

0.9≤A≤1.1 (6)

The voltage phase angle control range is:

Through changing duty ratio D ₁And D ₂Can change output voltage amplitude and phase angle.Common N<0.2 therefore, amplitude is regulated and is depended primarily on D ₁, phase angle is regulated and is depended primarily on D ₂

Because S ₁With S ₂Or S ₃With S ₄Alternately cut-off every group of switch (S ₁With S ₂Be one group, S ₃With S ₄Be another group) voltage that when turn-offing, born be rated voltage 2N doubly, thereby reduced electric pressure requirement to electronic power switch.

Fig. 2 is the voltage vector sketch map that the present invention changes the voltage phase angle principle, and Fig. 3 is that harmonic wave of output voltage of the present invention is analyzed sketch map, and is as shown in the figure; Output voltage does not contain low-order harmonic, only contains the switching frequency harmonic wave, therefore; Filtering easily; Because first and second power cell all contains high-frequency filter circuit,, thereby make the waveform of voltage of controlled three-phase transformer outputting high quality in addition filtering of high-frequency harmonic.

Fig. 4 is N=0.1, D ₁=0.5, D ₂=0 o'clock controlled three-phase transformer electronic power switch device voltage analogous diagram shows among the figure that electronic power switch device operating voltage is the sub-fraction of controlled three-phase transformer, i.e. 20% (2N doubly).Find out that from analogous diagram 5 output voltage response is very fast, Fig. 6 has found out phase shift about 11 degree, output amplitude has increased by 10%, and is consistent with above-mentioned analysis result.

Claims (3)

1. the controllable transformer device independently controlled of voltage magnitude and phase angle, it is characterized in that this device comprises: controlled three-phase transformer (1), first power cell (2), second power cell (8), measurement and control module (3), the winding element of connecting (4), input voltage instrument transformer (5) and output voltage instrument transformer (6) constitute:

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

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

Described 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) form;

Described second power cell (8) is by the 3rd switching power tube (S ₃), the 3rd switching power tube (S ₄), the second filter inductance (L _F2) the 3rd filter capacitor (C _F3) and the 4th filter capacitor (C _F4) form;

The described 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) constitute by 2 insulated gate bipolar transistor differential concatenations;

The described first switching power tube (S ₁) the plus tapping head (13) of the described controlled three-phase transformer of a termination (1) secondary, described second switch power tube (S ₂) a termination minus tapping head (11), this first group of switching power tube (S ₁) the other end and second group of switching power tube (S ₂) the other end link to each other and this tie point and the described first filter inductance (L _F1) an end link to each other this first filter inductance (L _F1) the other end respectively with an end, the 4th switching power tube (S of the described winding element of connecting (4) ₄) an end, the second filter capacitor (C _F2) an end link to each other the second filter capacitor (C _F2) the other end link to each other the other end of described series connection winding element (4) and the 3rd switching power tube (S with the secondary major joint (12) of described controlled three-phase transformer (1) ₃) an end link to each other described the 3rd switching power tube (S ₃) other end and the 4th switching power tube (S ₄) other end continuous and this tie point and the described second filter inductance (L _F2) an end link to each other this second filter inductance (L _F2) the other end connect out-put supply or load,

The described first 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 described the 3rd filter capacitor (C _F3) be connected across the 3rd switching power tube (S ₃) and the 4th switching power tube (S ₄) between the disjunct two ends, described the 4th filter capacitor (C _F4) an end and series connection winding element (4) in the tie points of 2 serial connection windings link to each other 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) links to each other with the former limit of controlled three-phase transformer input voltage main circuit, and voltage signal output end links to each other with the voltage signal input port of described measurement with control module (3);

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

The control signal output ends of described measurement and control module (3) respectively with the described 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 link to each other, this measurement links to each other with host computer with control module (3).

2. the controllable transformer device that voltage magnitude according to claim 1 and phase angle are independently controlled is characterized in that described measurement and control module (3) are digital signal processor, single-chip microcomputer or computer.

3. the controllable transformer device that utilizes described voltage magnitude of claim 1 and phase angle independently to control carries out the method for output voltage amplitude and phase angle control, it is characterized in that this 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 _AinBe A phase input voltage, V _BinBe B phase input voltage, V _CinBe C phase input voltage;

2) through pulse-width modulation the duty ratio of 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 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 following:

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

+(NV _bin-NV _cin)D ₂

4) with V in the step 1) _Ain, V _Bin, V _CinSubstitution formula (2) obtains:

(3)

5) output voltage amplitude is:

6) output voltage phase shift angle θ is:

。

Images