CN104537158A - Modeling method suitable for VSC-HVDC system and synchronous prototype - Google Patents
Modeling method suitable for VSC-HVDC system and synchronous prototype Download PDFInfo
- Publication number
- CN104537158A CN104537158A CN201410768664.2A CN201410768664A CN104537158A CN 104537158 A CN104537158 A CN 104537158A CN 201410768664 A CN201410768664 A CN 201410768664A CN 104537158 A CN104537158 A CN 104537158A
- Authority
- CN
- China
- Prior art keywords
- voltage
- phase
- average
- average voltage
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Landscapes
- Control Of Eletrric Generators (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention provides a modeling method suitable for VSC-HVDC system. The modeling method suitable for the VSC-HVDC system comprises the steps: step 1: average simplifying rectification loop; step 2: average simplifying inverter loop; and step 3: average simplifying direct current transmission loop. The invention further provides a relevant converter and a synchronous prototype. The rectification loop, direct current transmission loop and inverter loop of the synchronous prototype use an average value model to form a whole converter average value model. The modeling method suitable for the VSC-HVDC system is suitable for the grid-connected wind farm, and can satisfy most simulation requests under the situation without involving the converter control method.
Description
Technical field
The present invention relates to electrical engineering field, specifically a kind of be applicable to VSC-HVDC system modeling method and synchronous model machine.
Background technology
In recent years, Oversea wind power generation and conveying thereof are the focuses of the new forms of energy industries such as wind-powered electricity generation.Along with the fast development of Power Electronic Technique, voltage source converter type DC transmission system (VSC-HVDC) based on voltage source converter (VSC) and series connection igbt (IGBT) also ripe day by day, become a kind of novel means of offshore wind farm electric power conveying.At present, prior art still adopts conventional model, carries out the small synchronous model machine of real Time Dynamic Simulation or development 1:10 or 1:100 based on computer simulation software, research Oversea wind power generation VSC-HVDC system.Converter topology is relative maturity, does not study as a rule for converter control method, is used for model cootrol aspect without the need to spending great effort.In commercial Application, the system-wide core of VSC-HVDC is current transformer, and no matter from volume or economic aspect, controlled source is all better than current transformer.
There is following shortcoming in conventional model:
1, current transformer control strategy variation, pwm signal modulation is complicated;
2, in realistic model, whole system model buildings is complicated, and difficulty is high;
3, simulation calculation workload is large, and simulation velocity is slow;
When 4, developing small synchronous model machine, current transformer volume is comparatively large, and economic benefit is low.
Summary of the invention
For defect of the prior art, the object of this invention is to provide a kind of be applicable to VSC-HVDC system modeling method and synchronous model machine.The object of the invention is under the prerequisite guaranteeing simulation accuracy, in order to the simulation velocity of General Promotion VSC-HVDC system, Optimized model topological structure and the mathematical computations amount reduced in emulation, and simplify the difficulty of the synchronous model machine of development, propose by after the detailed model based on IGBT converter is simplified to mean value model, substitute in original system model again, simplify VSC-HVDC system model.
According to a kind of modeling method being applicable to VSC-HVDC system provided by the invention, comprise the steps:
Step 1: average simplification rectification link, the rectification Link Model of rectification link after average simplification, is specially:
The perunit value Uavg_rotor_conv being input as current transformer rectification side three-phase voltage reference signal of rectification Link Model, A, B two-phase wherein and B, C two-phase perunit value through and subtracting each other, obtain two line voltages, and then with obtain two line voltages respectively with DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively; Finally by average voltage Vab_avg and average voltage Vbc_avg through amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_rc and B, C two average voltage Vbc_rc of phase voltage of exporting after amplitude limit;
Step 2: average simplification inversion link, the inversion Link Model of inversion link after average simplification, is specially:
The three-phase alternating voltage perunit value Uavg_grid_conv being input as current transformer inverter side of inversion Link Model, by A, B two-phase wherein and B, C two phase voltage perunit value through subtracting each other, obtain two line voltages, and then with obtain two line voltages and DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively, be converted to current transformer real output value, finally by amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_gc and B, C two average voltage Vbc_gc of phase voltage of exporting after amplitude limit;
Step 3: average simplification direct current transmission link, the direct current transmission Link Model of direct current transmission link after average simplification is connected to rectification side and the inverter side of current transformer, the three-phase current being input as current transformer rectification side and inverter side of direct current transmission Link Model, after scale amplifying, associated with average voltage Vab_rc, average voltage Vbc_rc, average voltage Vab_gc, average voltage Vbc_gc by following two prime power formula:
P
ac＝V
ab·I
a-V
bc·I
c(1)
P
dc＝V
dc·I
dc(2)
Wherein, P
acrepresent the interchange active power of input, V
abrepresent the average voltage Vab_rc that step 1 obtains and the average voltage Vab_gc that step 2 obtains, I
arepresent the A phase current collected, V
bcrepresent the average voltage Vbc_rc that step 1 obtains and the average voltage Vbc_gc that step 2 obtains, I
crepresent the C phase current collected, P
dcrepresent direct current active power, V
dcrepresent DC voltage, I
dcrepresent DC current, expression is multiplied.
Preferably, step 3: average simplification direct current transmission link, the direct current transmission Link Model of direct current transmission link after average simplification, is specially:
One of direct current transmission Link Model is input as inverter side three-phase alternating current perunit value Iabc_grid_conv_pu, obtain with step 2 after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_gc of phase voltage be multiplied the long-pending C phase current scale amplifying deducted wherein be converted into actual value after with step 2 obtain B, C two the average voltage Vbc_gc of phase voltage be multiplied long-pending, namely obtain the interchange active-power P of inverter side
ac, by the interchange active-power P of inverter side obtained
acdivided by DC voltage V
dc, then the DC current Idc_gc that inverter side is corresponding is obtained;
Another of direct current transmission Link Model is input as rectification side three-phase alternating current perunit value Iabc_rotor_pu, obtain with step 1 after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_rc of phase voltage be multiplied after the long-pending C phase current scale amplifying deducted wherein is converted into actual value and be multiplied long-pending with the average voltage Vbc_rc that step 1 obtains B, C two-phase, namely obtain the interchange active-power P of rectification side
ac, by the interchange active-power P of rectification side obtained
acdivided by DC voltage V
dc, then the DC current Idc_rc that rectification side is corresponding is obtained;
The difference of the DC current Idc_gc obtained and DC current Idc_rc is carried out PI adjustment, can DC voltage V be obtained
dc.
According to a kind of current transformer provided by the invention, the equivalent model of described current transformer for or comprise the model that the above-mentioned modeling method being applicable to VSC-HVDC system sets up.
According to the synchronous model machine of one provided by the invention, comprise as lower device:
First device: on average simplifying rectification link; The rectification Link Model of rectification link after average simplification, is specially:
The perunit value Uavg_rotor_conv being input as current transformer rectification side three-phase voltage reference signal of rectification Link Model, A, B two-phase wherein and B, C two-phase perunit value through and subtracting each other, obtain two line voltages, and then with obtain two line voltages respectively with DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively; Finally by average voltage Vab_avg and average voltage Vbc_avg through amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_rc and B, C two average voltage Vbc_rc of phase voltage of exporting after amplitude limit;
Second device, on average simplifying inversion link; The inversion Link Model of inversion link after average simplification, is specially:
The three-phase alternating voltage perunit value Uavg_grid_conv being input as current transformer inverter side of inversion Link Model, by A, B two-phase wherein and B, C two phase voltage perunit value through subtracting each other, obtain two line voltages, and then with obtain two line voltages and DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively, be converted to current transformer real output value, finally by amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_gc and B, C two average voltage Vbc_gc of phase voltage of exporting after amplitude limit;
3rd device, on average simplifying direct current transmission link; The direct current transmission Link Model of direct current transmission link after average simplification is connected to rectification side and the inverter side of current transformer, the three-phase current being input as current transformer rectification side and inverter side of direct current transmission Link Model, after scale amplifying, associated with average voltage Vab_rc, average voltage Vbc_rc, average voltage Vab_gc, average voltage Vbc_gc by following two prime power formula:
P
ac＝V
ab·I
a-V
bc·I
c(1)
P
dc＝V
dc·I
dc(2)
Wherein, P
acrepresent the interchange active power of input, V
abrepresent the average voltage Vab_rc that first device obtains and the average voltage Vab_gc that the second device obtains, I
arepresent the A phase current collected, V
bcrepresent the average voltage Vbc_rc that first device obtains and the average voltage Vbc_gc that the second device obtains, I
crepresent the C phase current collected, P
dcrepresent direct current active power, V
dcrepresent DC voltage, I
dcrepresent DC current, expression is multiplied.
Preferably, the direct current transmission Link Model of direct current transmission link after average simplification, is specially:
One of direct current transmission Link Model is input as inverter side three-phase alternating current perunit value Iabc_grid_conv_pu, obtain with the second device after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_gc of phase voltage be multiplied the long-pending C phase current scale amplifying deducted wherein be converted into actual value after with the second device obtain B, C two the average voltage Vbc_gc of phase voltage be multiplied long-pending, namely obtain the interchange active-power P of inverter side
ac, by the interchange active-power P of inverter side obtained
acdivided by DC voltage V
dc, then the DC current Idc_gc that inverter side is corresponding is obtained;
Another of direct current transmission Link Model is input as rectification side three-phase alternating current perunit value Iabc_rotor_pu, obtain with first device after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_rc of phase voltage be multiplied after the long-pending C phase current scale amplifying deducted wherein is converted into actual value and be multiplied long-pending with the average voltage Vbc_rc that first device obtains B, C two-phase, namely obtain the interchange active-power P of rectification side
ac, by the interchange active-power P of rectification side obtained
acdivided by DC voltage V
dc, then the DC current Idc_rc that rectification side is corresponding is obtained;
The difference of the DC current Idc_gc obtained and DC current Idc_rc is carried out PI adjustment, can DC voltage V be obtained
dc.
Compared with prior art, the present invention has following beneficial effect:
The rectification link of the synchronous model machine 1, in the present invention, direct current transmission link and inversion link adopt mean value model, form complete current transformer mean value model, being applicable to wind farm grid-connected, when not relating to converter control method, most of simulation requirements can being met.
2, adopt current transformer mean value model without the need to considering complicated current transformer control strategy, model complexity step-down, model buildings is easy.
3, adopt current transformer mean value model to substitute the current transformer detailed model of tradition based on IGBT, VSC-HVDC system model topological structure is simplified greatly.
4, adopt current transformer mean value model, without the need to considering the calculating such as such as electro-magnetic transient, the mathematical computations amount of emulation greatly reduces, and simulation time shortens, and simulation efficiency improves.
5, when being ensured in the many performances of current transformer, if adopt this realistic model, its simulation result and former detailed converter system reach unanimity, then can with the voltage drawn under this realistic model, current status is selected the passive device except current transformer and is adjusted transformer parameter etc.
6, the present invention in the industry, synchronous simplified model is set up to Iarge-scale system, when current transformer performance is ensured, during type selecting to other passive device or other material, adopt this simplified model and corresponding synchronous model machine, replace current transformer with controlled source, can greatly increase economic efficiency and resource utilization.
Accompanying drawing explanation
By reading the detailed description done non-limiting example with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:
Fig. 1 is the mean value model of rectification link.
Fig. 2 is the mean value model of inversion link.
Fig. 3 is the mean value model of direct current transmission link.
Fig. 4 is the encapsulation of current transformer mean value model.
Fig. 5 is the VSC-HVDC system simulation model based on current transformer mean value model.
Fig. 6 is simplified model active power waveform.
Fig. 7 is conventional model active power waveform.
Fig. 8 is simplified model DC voltage waveform.
Fig. 9 is conventional model DC voltage waveform.
Embodiment
Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art and understand the present invention further, but not limit the present invention in any form.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, some distortion and improvement can also be made.These all belong to protection scope of the present invention.
The present invention is in order to simplify VSC-HVDC total system model and synchronous model machine thereof, consider that mean value model can be ignored the numerous and diverse degree of VSC-HVDC system, need not consider the time varying characteristic of system in detail in simplification process, propose and adopt the mean value model of current transformer to substitute the current transformer detailed model of tradition based on IGBT.For three links of current transformer, i.e. rectification, direct current transmission and inversion link construct mean value model respectively, and finally unification is encapsulated as the mean value model of whole current transformer, thus the synchronous model machine that can be simplified.The present invention is that a kind of simplification based on mean value model improves, and its simulation velocity that is simple and practical, that promote VSC-HVDC system, Optimized model topological structure and the mathematical computations amount reduced in emulation, can also ensure simulation accuracy simultaneously.The present invention is applicable to wind farm grid-connected, when not relating to converter control method, can meet most of simulation requirements.
The invention is characterized in:
(1) traditional current transformer model is simplified from rectification, inversion, direct current transmission three links;
(2) gather voltage and the electric current of rectification in VSC-HVDC system and inversion both sides, substitute current transformer with corresponding equivalent controlled source;
(3) this short-cut method is utilized to set up the synchronous simplified model of original system and synchronous model machine;
(4) in VSC-HVDC system, to select other elements except inverter controller (as passive device, or transformer etc.) time or investigate element function, take simplified model of the present invention and synchronous model machine, then without the need to designing current transformer and controller thereof.Thus greatly increase economic efficiency and resource utilization.
Modeling method provided by the invention, as shown in Figure 1, the perunit value being input as rectification side three-phase voltage reference signal of this link, subtracts each other through two-phase, phase voltage is converted to line voltage, then with the line voltage obtained and DC voltage V
dcbe multiplied, this DC voltage draws by direct current transmission link, is the actual input value of current transformer, finally again through amplitude limit (+V by the voltage transitions of acquisition
dc,-V
dc) export final magnitude of voltage afterwards.As shown in Figure 2, the structure of rectification and inversion both sides is basically identical, so the mean value model of inverter side and rectification side is also substantially the same.The three-phase dc voltage being input as inverter side of inversion link, after converting line voltage to and V
dcbe multiplied, export again after obtaining limiting voltage.As shown in Figure 3, the three-phase current being input as rectification side and inverter side of direct current transmission link, after scale amplifying, obtain before four voltages associate by through type (1), formula (2).The active power of rectification side save mean value model by rectification side three-phase current and collector ring before and obtains two voltages and calculate, and two voltages that the active power of inverter side has the three-phase current of inverter side and the mean value model of inversion link before to obtain calculate.Suppose noenergy loss, i.e. rectification side, the active power that electrical network injects to transverter is equal with the DC side power of transverter; Inverter side, DC side power is equal with the active power at transverter nearly user side place, through type (2), draw both sides DC current (note: obtain electric current by the equal backstepping of power, after according to PI regulate obtain DC voltage).The difference of the DC current calculated on both sides, as the input of DC capacitor, eventually passes integral element and obtains DC voltage.Current transformer provided by the invention current transformer mean value model, as shown in Figure 4, this mean value model has 4 inputs, correspond to the input of rectification, direct current transmission and inversion three links respectively, is rectification side three-phase voltage and three-phase current and inverter side three-phase voltage and three-phase current respectively.Meanwhile, also having 5 output ports, is two voltages exporting of two voltages, inversion link that rectification link exports and the DC voltage value that obtains of direct current transmission link respectively.
More specifically, modeling method provided by the invention is a kind of short-cut method to current transformer model in VSC-HVDC system, comprises the following steps:
Step 1: average simplification rectification link.
As shown in Figure 1, be rectification link simplify after rectification Link Model.The perunit value Uavg_rotor_conv being input as current transformer rectification side three-phase voltage reference signal of rectification Link Model, to wherein A, B two-phase and B, C two-phase perunit value process to subtract each other, two line voltages can be obtained, and then with obtain two line voltages respectively with DC voltage V
dcbe multiplied, this DC voltage V
dcobtain by direct current transmission Link Model below, then two voltages obtained that are multiplied are averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively, are converted to the actual input value of current transformer; Finally by amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_rc and B, C two average voltage Vbc_rc of phase voltage of exporting after amplitude limit.
In Fig. 1:
Uavg_rotor_conv represents: the perunit value of current transformer rectification side three-phase voltage reference signal;
0.5 represents: by A, B two phase voltage average
Vab_avg represents: A, B two average voltage of phase voltage
Vbc_avg represents: B, C two average voltage of phase voltage
Up represents: output voltage limit
Lo represents: output voltage lower limit
U represents: input, represents voltage
Y represents: export, and represents voltage
Vab_rc represents: A, B of exporting after amplitude limit two average voltage of phase voltage
Vbc_rc represents: B, C of exporting after amplitude limit two average voltage of phase voltage
Step 2: average simplification inversion link.
As shown in Figure 2, the structural symmetry of rectification and inverter side, so the mean value model of inverter side and rectification side basically identical.As shown in Figure 2, be inversion Link Model after inversion link on average simplifies.The three-phase alternating voltage perunit value Uavg_grid_conv being input as current transformer inverter side of inversion Link Model, by A, B two-phase wherein and B, C two phase voltage perunit value through subtracting each other, two line voltages can be obtained, and then with obtain two line voltages and DC voltage V
dcbe multiplied, this DC voltage V
dcobtain by direct current transmission Link Model below, then two voltages obtained that are multiplied are averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively, are converted to current transformer real output value, finally by amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_gc and B, C two average voltage Vbc_gc of phase voltage of exporting after amplitude limit.
In Fig. 2:
Uavg_grid_conv represents: the three-phase alternating voltage perunit value that inverter side collects;
0.5 represent: by A, B or B, C two phase voltage average
Vab_avg represents: A, B two average voltage of phase voltage
Vbc_avg represents: B, C two average voltage of phase voltage
Up represents: output voltage limit
Lo represents: output voltage lower limit
U represents: input, represents voltage
Y represents: export, and represents voltage
Vab_gc represents: A, B of exporting after amplitude limit two average voltage of phase voltage
Vbc_gc represents: B, C of exporting after amplitude limit two average voltage of phase voltage
Step 3: average simplification direct current transmission link.
As shown in Figure 3, direct current transmission Link Model is connected to rectification side and the inverter side of current transformer, the three-phase current being input as current transformer rectification side and inverter side of direct current transmission Link Model, after scale amplifying, associated with four voltages obtained before by following two prime power formula:
P
ac＝V
ab·I
a-V
bc·I
c(1)
P
dc＝V
dc·I
dc(2)
Wherein, P
acrepresent the interchange active power of input, V
abrepresent the average voltage Vab_rc that step 1 obtains and the average voltage Vab_gc that step 2 obtains, I
arepresent the A phase current collected, V
bcrepresent the average voltage Vbc_rc that step 1 obtains and the average voltage Vbc_gc that step 2 obtains, I
crepresent the C phase current collected, P
dcrepresent direct current active power, V
dcrepresent DC voltage, I
dcrepresent DC current, expression is multiplied;
In Fig. 3:
Iabc_grid_conv_pu represents: the three-phase alternating current perunit value that net side and inverter side collect;
Pu->A represents: scale amplifying, and perunit value is converted into actual value;
Vab_gc represents: step 2 obtains the average voltage level of A, B phase;
Vbc_gc represents: step 2 obtains the average voltage level of B, C phase;
P
acrepresent: exchange active power;
V
dcrepresent: DC voltage;
Idc_gc represents: the DC current calculated by net side active power and DC voltage;
Iabc_rotor_pu represents: the three-phase alternating current perunit value that rectification side collects;
Vab_rc represents: step 1 obtains the average voltage level of A, B phase;
Vbc_rc represents: step 1 obtains the average voltage level of B, C phase;
Idc_rc represents: the DC current calculated by rectification side active power and DC voltage;
1/C represents: proportional component;
Discrete Time integrator represents: integral element;
K represents: integral element coefficient, adjustable;
Ts represents: the sampling time;
Z-1 represents: converted the integrated form obtained to Z territory by time domain;
V
dcrepresent: DC voltage.
The active power of rectification side saves mean value model by rectification side three-phase current and collector ring before and obtains two voltages and calculate, two voltages that the active power of inverter side is obtained by three-phase current and the mean value model of inversion link before of inverter side calculate, and therefore just can obtain the performance number on both sides.In addition, because direct current transmission link is connected to rectification link and inversion link, capacitance voltage cannot suddenly change, then the DC voltage that obtains of its both sides is necessarily consistent.Meanwhile, contrast detailed model, the loss of same hypothesis noenergy, i.e. rectification side, the active power that electrical network injects to transverter is equal with the DC side power of transverter; Inverter side, DC side power is equal with the active power at transverter nearly user side place, namely by law of conservation of energy application wherein, can be drawn the DC current on both sides by formula (2).The difference of the DC current calculated on both sides is as the input of DC capacitor, and wherein DC capacitor occurs with the form of proportional component in mean value model, is the 1/C in figure, eventually passes integral element and obtains DC voltage.So far, the averaging model of direct current transmission link has built.
Structure shown in Fig. 3, the first half is input as inverter side three-phase alternating current perunit value Iabc_grid_conv_pu, obtain with step 2 after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_gc of phase voltage be multiplied the long-pending C phase current scale amplifying deducted wherein be converted into actual value after with step 2 obtain B, C two the average voltage Vbc_gc of phase voltage be multiplied long-pending, namely obtain the interchange active-power P of inverter side
ac, due to power-balance, by the interchange active-power P of inverter side obtained
acdivided by DC voltage V
dc, then the DC current Idc_gc that inverter side is corresponding is obtained.The latter half is input as rectification side three-phase alternating current perunit value Iabc_rotor_pu, obtain with step 1 after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_rc of phase voltage be multiplied after the long-pending C phase current scale amplifying deducted wherein is converted into actual value and be multiplied long-pending with the average voltage Vbc_rc that step 1 obtains B, C two-phase, namely obtain the interchange active-power P of rectification side
ac, due to power-balance, by the interchange active-power P of rectification side obtained
acdivided by DC voltage V
dc, then the DC current Idc_rc that rectification side is corresponding is obtained.The difference of the DC current Idc_gc obtained and DC current Idc_rc is carried out PI adjustment, can DC voltage V be obtained
dc(namely described in step 1,2, obtain DC voltage V by direct current transmission Link Model
dc).
Step 4: the encapsulation of current transformer mean value model, as shown in Figure 4, is encapsulated the mean value model that just can obtain integrating rectification, direct current transmission and inversion by unified for above three links, that is current transformer mean value model.As can be seen from Figure, this mean value model has 4 inputs, correspond to the input of rectification, direct current transmission and inversion three links respectively, is rectification side three-phase voltage and three-phase current and inverter side three-phase voltage and three-phase current respectively.Meanwhile, also having 5 output ports, is two voltages exporting of two voltages, inversion link that rectification link exports and the DC voltage value that obtains of direct current transmission link respectively, obviously also corresponding with the output of upper figure tri-links.
In Fig. 4:
Uavg_grid_conv represents: the three-phase alternating voltage perunit value that inverter side collects
Uavg_rotor_conv represents: the three-phase alternating voltage perunit value that rectification side collects;
Iabc_grid_conv_pu represents: the three-phase alternating current perunit value that net side and inverter side collect;
Iabc_rotor_pu represents: the three-phase alternating current perunit value that rectification side collects;
Vab_gc represents: step 2 obtains the average voltage level of A, B phase;
Vbc_gc represents: step 2 obtains the average voltage level of B, C phase;
Vab_rc represents: step 1 obtains the average voltage level of A, B phase;
Vbc_rc represents: step 1 obtains the average voltage level of B, C phase;
Vdc represents: DC voltage.
So far, complete current transformer mean value model has successfully been built.
The output AC voltage output quantity of rectification side and inverter side current transformer is line voltage, and (as shown in Figure 5, rectification side is V to be connected respectively to two controlled voltage sources
ab_gc, V
bc_gc; Inverter side is two other), finally by the voltage transitions of controlled voltage source to current transformer three-phase alternating voltage, be connected to other parts of principal current, just can replace the detailed current transformer model based on IGBT.
In Fig. 5:
AC voltage source: alternating-current voltage source;
Three-phase V-I measurement: three-phase alternating voltage, current measurement rod;
Three-phase transformer: three-phase transformer;
Three-phase serial RLC branch: three phase of impedance;
Converter average model: current transformer mean value model;
Uavg_grid_conv represents: the three-phase alternating voltage perunit value that inverter side collects
Uavg_rotor_conv represents: the three-phase alternating voltage perunit value that rectification side collects;
Iabc_grid_conv_pu represents: the three-phase alternating current perunit value that net side and inverter side collect;
Iabc_rotor_pu represents: the three-phase alternating current perunit value that rectification side collects;
Vab_gc represents: step 2 obtains the average voltage level of A, B phase, in this case controlled source;
Vbc_gc represents: step 2 obtains the average voltage level of B, C phase, in this case controlled source;
Vab_rc represents: step 1 obtains the average voltage level of A, B phase, in this case controlled source;
Vbc_rc represents: step 1 obtains the average voltage level of B, C phase, in this case controlled source;
Vdc represents: DC voltage.
Embodiment:
The application of current transformer mean value model in VSC-HVDC system simulation model.
Fig. 5 is the VSC-HVDC system simulation model based on current transformer mean value model.The model left side is the equivalent three-phase supply of Wind turbines, and rectification side and inverter side all adopt the mean value model of current transformer, and right side is electrical network.Whole wind-electricity integration system, its concrete simulation parameter as listed in table 1:
Table 1 simplifies system emulation parameter
The specified applied power of note: P--;
U
f--ac line voltage;
Udc--DC voltage;
F--mains frequency;
L--inductance value, R--resistance, C--electric capacity;
Simulation result is as shown in Figure of description, and wherein Fig. 6 is simplified model active power waveform, and Fig. 7 is conventional model active power waveform, and Fig. 8 is simplified model DC voltage waveform, and Fig. 9 is conventional model DC voltage waveform.By the scheme adopting current transformer mean value model to replace detailed IGBT converter, MatLab builds simplified model and has emulated, according to simulation result, two models can be contrasted from following two aspects: (1) accuracy, conventional model and simplified model the waveform of rectification side, direct current transmission and inverter side three links and numerical value very close; (2) efficiency, owing to not calculating detailed transient state process, no matter simplified model is topological structure or calculated amount, is all far superior to original detailed model.
In order to verify the feasibility of simplified model, run VSC-HVDC detailed model and simplified model respectively.Worked out the program of a computing time, the code of this program is as follows:
tic
sim('hvdc690_500_piungjun',[01])
time_pingjun＝toc
tic
sim('hvdc690_500_xiangxi',[01])
time_xiangxi＝toc，
So, the simulation time of two models is obtained at Matlab command window.Based in Matlab analogue system, the simulation run time of detailed model is 29.0487s, and the simulation run time of simplified model is 18.3801s, visible, simplified model saves the nearly 10s time, and its calculated amount is far smaller than detailed model, and simplified model operational efficiency is high.
Technical solution of the present invention becomes current transformer averaging model by tradition being replaced based on the current transformer detailed model of IGBT, thus enormously simplify the topological structure of VSC-HVDC total system model, simulation calculation amount reduces greatly.
Above specific embodiments of the invention are described.It is to be appreciated that the present invention is not limited to above-mentioned particular implementation, those skilled in the art can make various distortion or amendment within the scope of the claims, and this does not affect flesh and blood of the present invention.
Claims (5)
1. be applicable to a modeling method for VSC-HVDC system, it is characterized in that, comprise the steps:
Step 1: average simplification rectification link, the rectification Link Model of rectification link after average simplification, is specially:
The perunit value Uavg_rotor_conv being input as current transformer rectification side three-phase voltage reference signal of rectification Link Model, A, B two-phase wherein and B, C two-phase perunit value through and subtracting each other, obtain two line voltages, and then with obtain two line voltages respectively with DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively; Finally by average voltage Vab_avg and average voltage Vbc_avg through amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_rc and B, C two average voltage Vbc_rc of phase voltage of exporting after amplitude limit;
Step 2: average simplification inversion link, the inversion Link Model of inversion link after average simplification, is specially:
The three-phase alternating voltage perunit value Uavg_grid_conv being input as current transformer inverter side of inversion Link Model, by A, B two-phase wherein and B, C two phase voltage perunit value through subtracting each other, obtain two line voltages, and then with obtain two line voltages and DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively, be converted to current transformer real output value, finally by amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_gc and B, C two average voltage Vbc_gc of phase voltage of exporting after amplitude limit;
Step 3: average simplification direct current transmission link, the direct current transmission Link Model of direct current transmission link after average simplification is connected to rectification side and the inverter side of current transformer, the three-phase current being input as current transformer rectification side and inverter side of direct current transmission Link Model, after scale amplifying, associated with average voltage Vab_rc, average voltage Vbc_rc, average voltage Vab_gc, average voltage Vbc_gc by following two prime power formula:
P
ac＝V
ab·I
a-V
bc·I
c(1)
P
dc＝V
dc·I
dc(2)
Wherein, P
acrepresent the interchange active power of input, V
abrepresent the average voltage Vab_rc that step 1 obtains and the average voltage Vab_gc that step 2 obtains, I
arepresent the A phase current collected, V
bcrepresent the average voltage Vbc_rc that step 1 obtains and the average voltage Vbc_gc that step 2 obtains, I
crepresent the C phase current collected, P
dcrepresent direct current active power, V
dcrepresent DC voltage, I
dcrepresent DC current, expression is multiplied.
2. the modeling method being applicable to VSC-HVDC system according to claim 1, is characterized in that,
Step 3: average simplification direct current transmission link, the direct current transmission Link Model of direct current transmission link after average simplification, is specially:
One of direct current transmission Link Model is input as inverter side three-phase alternating current perunit value Iabc_grid_conv_pu, obtain with step 2 after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_gc of phase voltage be multiplied the long-pending C phase current scale amplifying deducted wherein be converted into actual value after with step 2 obtain B, C two the average voltage Vbc_gc of phase voltage be multiplied long-pending, namely obtain the interchange active-power P of inverter side
ac, by the interchange active-power P of inverter side obtained
acdivided by DC voltage V
dc, then the DC current Idc_gc that inverter side is corresponding is obtained;
Another of direct current transmission Link Model is input as rectification side three-phase alternating current perunit value Iabc_rotor_pu, obtain with step 1 after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_rc of phase voltage be multiplied after the long-pending C phase current scale amplifying deducted wherein is converted into actual value and be multiplied long-pending with the average voltage Vbc_rc that step 1 obtains B, C two-phase, namely obtain the interchange active-power P of rectification side
ac, by the interchange active-power P of rectification side obtained
acdivided by DC voltage V
dc, then the DC current Idc_rc that rectification side is corresponding is obtained;
The difference of the DC current Idc_gc obtained and DC current Idc_rc is carried out PI adjustment, can DC voltage V be obtained
dc.
3. a current transformer, is characterized in that, the model that the equivalent model of described current transformer is set up for the modeling method being applicable to VSC-HVDC system described in claim 1 or 2.
4. a synchronous model machine, is characterized in that, comprises as lower device:
First device: on average simplifying rectification link; The rectification Link Model of rectification link after average simplification, is specially:
The perunit value Uavg_rotor_conv being input as current transformer rectification side three-phase voltage reference signal of rectification Link Model, A, B two-phase wherein and B, C two-phase perunit value through and subtracting each other, obtain two line voltages, and then with obtain two line voltages respectively with DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively; Finally by average voltage Vab_avg and average voltage Vbc_avg through amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_rc and B, C two average voltage Vbc_rc of phase voltage of exporting after amplitude limit;
Second device, on average simplifying inversion link; The inversion Link Model of inversion link after average simplification, is specially:
The three-phase alternating voltage perunit value Uavg_grid_conv being input as current transformer inverter side of inversion Link Model, by A, B two-phase wherein and B, C two phase voltage perunit value through subtracting each other, obtain two line voltages, and then with obtain two line voltages and DC voltage V
dcbe multiplied, then two voltages obtained that are multiplied be averaged to obtain average voltage Vab_avg and average voltage Vbc_avg respectively, be converted to current transformer real output value, finally by amplitude limit (+V
dc,-V
dc) export final magnitude of voltage afterwards and be: A, B of exporting after amplitude limit two phase voltage average voltage Vab_gc and B, C two average voltage Vbc_gc of phase voltage of exporting after amplitude limit;
3rd device, on average simplifying direct current transmission link; The direct current transmission Link Model of direct current transmission link after average simplification is connected to rectification side and the inverter side of current transformer, the three-phase current being input as current transformer rectification side and inverter side of direct current transmission Link Model, after scale amplifying, associated with average voltage Vab_rc, average voltage Vbc_rc, average voltage Vab_gc, average voltage Vbc_gc by following two prime power formula:
P
ac＝V
ab·I
a-V
bc·I
c(1)
P
dc＝V
dc·I
dc(2)
Wherein, P
acrepresent the interchange active power of input, V
abrepresent the average voltage Vab_rc that first device obtains and the average voltage Vab_gc that the second device obtains, I
arepresent the A phase current collected, V
bcrepresent the average voltage Vbc_rc that first device obtains and the average voltage Vbc_gc that the second device obtains, I
crepresent the C phase current collected, P
dcrepresent direct current active power, V
dcrepresent DC voltage, I
dcrepresent DC current, expression is multiplied.
5. synchronous model machine according to claim 4, is characterized in that, the direct current transmission Link Model of direct current transmission link after average simplification, is specially:
One of direct current transmission Link Model is input as inverter side three-phase alternating current perunit value Iabc_grid_conv_pu, obtain with the second device after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_gc of phase voltage be multiplied the long-pending C phase current scale amplifying deducted wherein be converted into actual value after with the second device obtain B, C two the average voltage Vbc_gc of phase voltage be multiplied long-pending, namely obtain the interchange active-power P of inverter side
ac, by the interchange active-power P of inverter side obtained
acdivided by DC voltage V
dc, then the DC current Idc_gc that inverter side is corresponding is obtained;
Another of direct current transmission Link Model is input as rectification side three-phase alternating current perunit value Iabc_rotor_pu, obtain with first device after A phase current scale amplifying is wherein converted into actual value A, B two the average voltage Vab_rc of phase voltage be multiplied after the long-pending C phase current scale amplifying deducted wherein is converted into actual value and be multiplied long-pending with the average voltage Vbc_rc that first device obtains B, C two-phase, namely obtain the interchange active-power P of rectification side
ac, by the interchange active-power P of rectification side obtained
acdivided by DC voltage V
dc, then the DC current Idc_rc that rectification side is corresponding is obtained;
The difference of the DC current Idc_gc obtained and DC current Idc_rc is carried out PI adjustment, can DC voltage V be obtained
dc.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410768664.2A CN104537158B (en) | 2014-12-12 | 2014-12-12 | Modeling method and synchronous model machine suitable for VSC HVDC systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410768664.2A CN104537158B (en) | 2014-12-12 | 2014-12-12 | Modeling method and synchronous model machine suitable for VSC HVDC systems |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104537158A true CN104537158A (en) | 2015-04-22 |
| CN104537158B CN104537158B (en) | 2017-11-14 |
Family
ID=52852685
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410768664.2A Active CN104537158B (en) | 2014-12-12 | 2014-12-12 | Modeling method and synchronous model machine suitable for VSC HVDC systems |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104537158B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0056659B1 (en) * | 1981-01-21 | 1985-09-25 | Hitachi, Ltd. | Converter control apparatus for parallel connected multi-terminal direct current system |
| WO2006035018A2 (en) * | 2004-09-27 | 2006-04-06 | Areva T & D Uk Ltd | A direct current power transmission system and associated control method |
| CN103715716A (en) * | 2013-12-27 | 2014-04-09 | 上海交通大学 | Alternating current-direct current parallel system seamless switching control method based on VSC-HVDC |
| CN103840479A (en) * | 2013-12-16 | 2014-06-04 | 南方电网科学研究院有限责任公司 | Start control method for VSC-HVDC-based alternating current-direct current parallel system |
-
2014
- 2014-12-12 CN CN201410768664.2A patent/CN104537158B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0056659B1 (en) * | 1981-01-21 | 1985-09-25 | Hitachi, Ltd. | Converter control apparatus for parallel connected multi-terminal direct current system |
| WO2006035018A2 (en) * | 2004-09-27 | 2006-04-06 | Areva T & D Uk Ltd | A direct current power transmission system and associated control method |
| CN103840479A (en) * | 2013-12-16 | 2014-06-04 | 南方电网科学研究院有限责任公司 | Start control method for VSC-HVDC-based alternating current-direct current parallel system |
| CN103715716A (en) * | 2013-12-27 | 2014-04-09 | 上海交通大学 | Alternating current-direct current parallel system seamless switching control method based on VSC-HVDC |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104537158B (en) | 2017-11-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100521485C (en) | LCL filtering based voltage type active rectifier steady control system and method | |
| CN105140907B (en) | Direct-current micro-grid multiple agent adaptively sagging uniformity control method for coordinating and device | |
| CN103208815B (en) | d-q axis parameter identification method for grid-connected inverter of photovoltaic power generation system | |
| CN103020385B (en) | Based on RTDS electrical network 500kV major network modeling and simulating system | |
| CN108280271B (en) | Unified power flow controller equivalent modeling method based on switching period average principle | |
| CN106374528A (en) | Microgrid dispersing type control policy model based on improved droop control | |
| CN103544378A (en) | Method for calculating harmonic wave impedance of alternating current system for direct current transmission | |
| CN108599605A (en) | Three-level inverter model prediction Poewr control method based on two Vector modulations | |
| CN107086576B (en) | A kind of Distributed Power Flow controller Multiple Time Scales mathematical model establishing method | |
| CN106549417A (en) | A kind of virtual synchronous generator control method and device of photovoltaic energy storage system | |
| CN108880300B (en) | Double-fed fan rectifier impedance calculation method based on double closed-loop control | |
| CN105006839A (en) | Weak power grid source load impedance model analysis method of grid-connected power generation system | |
| CN109066725B (en) | Direct-drive fan equivalent modeling method for subsynchronous oscillation simulation | |
| CN110137949A (en) | A kind of method and device for the mains by harmonics characteristic obtaining the station containing new energy | |
| CN103986187A (en) | Method for damping control of LCL grid-connected inverter based on dimension reduction observation | |
| CN110135039A (en) | Wind-powered electricity generation collects regional non-equilibrium among three phase voltages and determines method and device | |
| CN108205595B (en) | PSCAD double-fed wind turbine simulation model system suitable for harmonic analysis | |
| CN111769597A (en) | Dimension reduction modeling analysis method of doubly-fed wind generator | |
| CN104600694A (en) | Micro-grid energy optimization method considering economic dispatch and loop current suppression | |
| CN104237700B (en) | Microgrid semi-physical testing circuit and method on basis of feedback type load simulator | |
| CN113852120A (en) | Method and system for determining maximum grid-connected capacity of new energy power generation | |
| CN108984847B (en) | Real-time digital hybrid simulation interface method based on frequency division impedance compensation | |
| CN203326911U (en) | Inverter controller and wind generator system | |
| CN106712028A (en) | Power flow calculation method for alternating-current/direct-current grid with consideration of power load fluctuation | |
| CN113241779B (en) | Stability analysis method and device for direct-drive wind power plant grid-connected system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |