CN107085136A - A kind of three-phase alternating voltage falls the determination methods and system of state - Google Patents
A kind of three-phase alternating voltage falls the determination methods and system of state Download PDFInfo
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Abstract
The invention provides the determination methods and system that a kind of three-phase alternating voltage falls state, its determination methods includes:Sampled voltage is changed to two-phase rotating coordinate system from three-phase static coordinate system;Under two-phase rotating coordinate system, isolated d axles DC voltage component U is decoupleddWith q axle DC voltage components Uq;Using filtering d axle DC voltage components UdWith q axle DC voltage components UqThe d axle DC voltage components U obtained afterwardsdfltWith q axle DC voltage components Uqflt, judge whether line voltage falls.The present invention realizes the quick control and protection to system by improving rapidity and accuracy of the system to Voltage Drop and recovery condition adjudgement.
Description
Technical field
The present invention relates to electric and electronic technical field, and in particular to a kind of three-phase alternating voltage falls the determination methods of state
And system.
Background technology
The problems such as due to ambient influnence, geographical limitation and scarcity of resources, current power generation has been gradually reduced to once
The dependence that the energy generates electricity, realizes distributing rationally for the global energy, hydroelectric generation, wind-power electricity generation, photovoltaic generation, biomass energy hair
The a series of new regenerative resources such as electricity, power generation with marine energy and geothermal power generation become the focus of research.The hair of regenerative resource
The features such as opening up also along with its randomness, intermittence, fluctuation and unpredictability, when its large-scale access power system
When, influence can be brought on the stability, reliability and the quality of power supply of power system.
Energy-storage system is to solve one of solution of regenerative resource access problem, and grid type energy-storage system is general by electricity
The part groups such as pond energy-storage units, energy storage energy conversion unit (Power ConverterSystem, PCS), step-up transformer unit
Into.After energy-storage system is grid-connected, it exports the quality of power supply, grid-connected discharge and recharge rule, and power adjusting ability and response characteristic will be right
The security reliability of power network produces influence.Equally, the quality of power supply of power network, the fluctuation of electric voltage frequency certainly will also be deposited to energy-storage system
In influence.Therefore, energy-storage system to the adaptability of power network especially grid voltage sags when energy storage converter system response characteristic
Research tool is of great significance.
Most common failure belongs to voltage magnitude mutation.Voltage magnitude mutation refer to grid voltage amplitude change so that
A kind of grid fault conditions of numerical value offrating, wherein Voltage Drop are most common failures.So-called Voltage Drop refers to
Unexpected depreciation occurs at any one place and recovers a kind of failure of normal work after the short time for line voltage, causes its original
Because the unreasonable input and alternate generation short trouble of mainly large-scale power grid load are made with falling depth and dip duration
For result caused by performance indications, the distance that the former occurs point by open circuit fault type and failure determines that the latter is then by protection
Type is determined.
At present, energy storage energy conversion unit PCS (power conversion system) uses dsp controller, works as electricity
When pressing amplitude of falling deeper, random electric current and voltage oscillation phenomenon occurs in voltage dip and during recovering, because
This, it is desirable to provide a kind of three-phase alternating voltage falls the determination methods of state to overcome the deficiencies in the prior art.
The content of the invention
In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides the judgement side that a kind of three-phase alternating voltage falls state
Method, its determination methods include:Sampled voltage is changed to two-phase rotating coordinate system from three-phase static coordinate system;Rotate and sit in two-phase
Under mark system, isolated d axles DC voltage component U is decoupleddWith q axle DC voltage components Uq;Divided using d axles DC voltage is filtered
Measure UdWith q axle DC voltage components UqThe d axle DC voltage components U obtained afterwardsdfltWith q axle DC voltage components Uqflt, judge electricity
Whether net voltage falls.
Under two-phase rotating coordinate system, isolated d axles and q axle DC voltage components U are decoupleddAnd Uq, specifically include:When
Positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively θ0 PAnd θ0 N, the Coordinate Conversion of positive sequence and negative sequence voltage
Angle is respectively θ0 PAnd θ0 NDuring -2 ω t, if rotating to be reference, meter of the positive sequence DC voltage component in d axles with positive sequence d axles and q axles
Calculate formula as follows:
Positive sequence DC voltage component is as follows in the calculation formula of q axles:
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For negative sequence voltage vector
D axis components,For the q axis components of negative sequence voltage vector.
Under rotating coordinate system, the d axles and q axis components of isolated positive sequence voltage and negative sequence voltage are decoupled, including:When just
Sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively θ0 PAnd θ0 N, the Coordinate Conversion angle of positive sequence and negative sequence voltage
Degree is respectively θ0 P+ 2 ω t and θ0 NWhen, if rotating to be reference, calculating of the negative phase-sequence DC voltage component in d axles with negative phase-sequence d axles and q axles
Formula is as follows:
Negative phase-sequence DC voltage component is as follows in the calculation formula of q axles:
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For negative sequence voltage vector
D axis components,For the q axis components of negative sequence voltage vector.
The component decoupling equation of d axles and q axles is as follows under two-phase rotating coordinate system:
WithIt is that Coordinate Conversion angle is θ respectively0 PAnd θ0 ND axle positive sequence DC voltage components and q axles during -2 ω t are just
Sequence DC voltage component,WithIt is that Coordinate Conversion angle is θ respectively0 P+ 2 ω t and θ0 NWhen d axle negative phase-sequence DC voltage components
With q axle negative phase-sequences DC voltage component,For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector,
For the d axis components of negative sequence voltage vector,For the q axis components of negative sequence voltage vector.
The d axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains d axles control component udr;
The q axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains q axles control component uqr。
D axle DC voltage components udWith q axles and DC voltage component uqCalculation formula is as follows:
In formula, u 'drWith u 'qrRespectively by the PI d axles adjusted and the output of q shaft currents ring, Δ udrWith Δ uqrRespectively d
The compensation term of axle and q shaft voltages.
Using filtering d axle DC voltage components UdWith q axle DC voltage components UqThe U obtained afterwardsdfltAnd Uqflt, specific bag
Include:D axle DC voltage components udWith q axle DC voltage components uqLow-pass filtered device obtains udfltAnd uqflt。
Judge whether line voltage falls, specifically include:Interpretation is carried out to grid voltage sags flag bit with following formula, when
When, it is 1 to occur Voltage Drop power network to fall flag bit;
In formula,For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector, UdropTo be pre-
If value.
Its judgement system includes:Modular converter, rotates for sampled voltage to be changed to two-phase from three-phase static coordinate system
Coordinate system;Separation module is decoupled, under two-phase rotating coordinate system, decoupling isolated d axles DC voltage component UdWith q axles
DC voltage component Uq;Judge module, using filtering d axle DC voltage components UdWith q axle DC voltage components UqThe d obtained afterwards
Axle DC voltage component UdfltWith q axle DC voltage components Uqflt, judge whether line voltage falls.
Separation module is decoupled, specifically for:As positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively
θ0 PAnd θ0 N, the Coordinate Conversion angle of positive sequence and negative sequence voltage is respectively θ0 PAnd θ0 NDuring -2 ω t, if being rotated with positive sequence d axles and q axles
To refer to, positive sequence DC voltage component is as follows in the calculation formula of d axles:
Positive sequence DC voltage component is as follows in the calculation formula of q axles:
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For negative sequence voltage vector
D axis components,For the q axis components of negative sequence voltage vector.
Separation module is decoupled, specifically for:As positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively
θ0 PAnd θ0 N, the Coordinate Conversion angle of positive sequence and negative sequence voltage is respectively θ0 P+ 2 ω t and θ0 NWhen, if being rotated with negative phase-sequence d axles and q axles
To refer to, negative phase-sequence DC voltage component is as follows in the calculation formula of d axles:
Negative phase-sequence DC voltage component is as follows in the calculation formula of q axles:
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For negative sequence voltage vector
D axis components,For the q axis components of negative sequence voltage vector.
The component decoupling equation of d axles and q axles is as follows under two-phase rotating coordinate system:
WithIt is that Coordinate Conversion angle is θ respectively0 PAnd θ0 ND axle positive sequence DC voltage components and q axles during -2 ω t are just
Sequence DC voltage component,WithIt is that Coordinate Conversion angle is θ respectively0 P+ 2 ω t and θ0 NWhen d axle negative phase-sequence DC voltage components
With q axle negative phase-sequences DC voltage component,For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector,
For the d axis components of negative sequence voltage vector,For the q axis components of negative sequence voltage vector.
The d axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains d axles control component Udr;
The q axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains q axles control component Uqr。
D axle DC voltage components udWith q axle DC voltage components uqCalculation formula is as follows:
In formula, u 'drWith u 'qrRespectively by the PI d axles adjusted and the output of q shaft currents ring, Δ udrWith Δ uqrRespectively d
The compensation term of axle and q shaft voltages.
D axle DC voltage components udWith the q axles DC voltage component uqLow-pass filtered device obtains udfltAnd uqflt。
Interpretation is carried out to grid voltage sags flag bit with following formula, when
When, it is 1 to occur Voltage Drop power network to fall flag bit;
In formula,For positive sequence voltage d axis components,For positive sequence voltage q axis components, UdropFor preset value.
Compared with immediate prior art, the technical scheme that the present invention is provided has the advantages that:
1st, the present invention using positive-negative sequence decoupling by the way of can improve the interpretation to grid voltage sags mode.
2nd, the present invention is realized by improving rapidity and accuracy of the system to Voltage Drop and recovery condition adjudgement
Quick control and protection to system.
3rd, the response speed judged when the present invention can improve energy storage energy conversion unit PCS for Voltage Drop voltage
Degree, when especially Voltage Drop is deeper, realizes accurate judgement of the system for voltage voltage when falling and recovering, so as to improve
Energy accumulation current converter is for the responding ability under grid voltage sags operating mode and control.
Brief description of the drawings
Fig. 1 is filtering schematic diagram of the invention;
Fig. 2 is the judgement schematic diagram of the Voltage Drop of the present invention.
Embodiment
Technical scheme is described in further details with reference to Figure of description.
Energy storage energy conversion unit PCS is using dsp chip as master controller, and it sentences for the state of grid voltage sags
It is disconnected to be realized by flag bit.When PCS normal works, grid voltage sags flag bit=0 is detected;When PCS is detected
When Voltage Drop occurs, grid voltage sags flag bit=1.
First, the conversion for the three-phase voltage obtained after sampling being carried out into 3s/2r is changed to two from three-phase static coordinate system
Cordic phase rotator system and the separation of positive-negative sequence component of voltage, now positive and negative order components are component of voltage values, and are not filtered, and are utilized
U is obtained after filteringdfltAnd uqfltJudge whether line voltage falls.
Because negative sequence component is 0 under balance, voltage is projected under positive-sequence component, in the case of imbalance just
Order components and negative sequence component are complementary, therefore are to understand whether this Voltage Drop occurs not by the interpretation to positive-sequence component
Balance is fallen and falls depth is how many.
In the case of the falling of three-phase imbalance, PCS is realized to grid entry point electricity by way of positive-negative sequence decoupling separation
The judgement and control of pressure, i.e., realize to unbalanced voltage by way of positive-negative sequence decoupling and separate.
If using positive sequence dq rotating coordinate systems as reference, positive sequence voltage is with direct rotational direction synchronous rotary (counterclockwise), negative phase-sequence
Voltage is then with negative direction of rotation synchronous rotary (clockwise).If positive-negative sequence voltage vector UPAnd UNInitial angle be θ0 PAnd θ0 N,
The Coordinate Conversion angle of so positive and negative sequence voltage is θ0 PAnd θ0 N- 2 ω t, expression formula of the positive sequence DC voltage component on d axles be
Similarly, expression formula of the positive sequence DC voltage component on q axles is
If using negative phase-sequence dq rotating coordinate systems as reference, then the coordinate transform angle of positive and negative sequence voltage is θ0 P+ 2 ω t and
θ0 N, expression formula of the negative phase-sequence DC voltage component on d axles be
Similarly, expression formula of the negative phase-sequence DC voltage component on q axles is
To sum up, formula of the voltage vector under positive and negative referential is drawn:
Can obtain required decoupling equation by above formula is
The d axis components of positive sequence voltage vector are represented,Represent the q axis components of positive sequence voltage vector;Represent negative phase-sequence electricity
The d axis components of vector are pressed,Represent the q axis components of negative sequence voltage vector.
The present invention realizes the quick judgement to voltage in order to follow-up by the decomposition to voltage under rotating coordinate system
Control.
D axles control component and q axles control component calculation formula are as follows under two cordic phase rotators:
Hereafter exemplified by under balanced voltage, i.e.,
udWith uqIt is the reference voltage under two cordic phase rotators, it is made up of three parts:The electric current loop adjusted by PI is defeated
Go out u 'dWith u 'q, the compensation term Δ u of voltagedrWith Δ uqrAnd two line voltage u under cordic phase rotatordrAnd uqr。
As shown in figure 1, in a program as DC component udAnd uqAdd after low pass filter, obtain filtered udfltWith
uqfltValue.
fcRepresent the cut-off frequency of wave filter, fsRepresent DSP sample frequency.
If the filter times of wave filter are higher, filtered amplitude will be smaller, its amplitude attenuation degree and wave filter
Cut-off frequency is relevant.In addition, when Voltage Drop, udfltWith uqfltResponse time number and cutoff frequency also with wave filter
Rate is relevant, and number is more, and cut-off frequency is lower, and the response time is slower.
WhenWhen, it is judged to falling, grid voltage sags flag bit is 1.Wherein:It is positive sequence voltage d axis components;It is positive sequence voltage q axis components, UdropFor preset value.
As shown in Fig. 2 t0During moment Voltage Drop, system is caused to judge that voltage has been opened by enabler flags position Flag_Ud
Beginning is fallen, and device is run into low voltage mode, at the same time, and flag bit Flag_Ud2 is enabled, and now voltage, which enters, falls area
Between, the interior frequency filtering using 2000Hz before t0+0.1, because frequency filtering is high, therefore the value fidelity and sound of the voltage sample
Answer speed;After 5 calculating cycles, i.e. 0.1ms, now voltage, which has left, falls interval, then reduces frequency filtering and be
5Hz, realizes the accurate filtering of voltage under stable state, t1Moment, flag bit Flag_Ud is reset to zero, and now voltage recovers to normal
Voltage status, flag bit Flag_Ud3 is enabled, and voltage, which enters, recovers interval, and now frequency filtering switches to 2000Hz again, realizes
Quick filter.
It should be understood by those skilled in the art that, embodiments herein can be provided as method, system or computer program
Product.Therefore, the application can be using the reality in terms of complete hardware embodiment, complete software embodiment or combination software and hardware
Apply the form of example.Moreover, the application can be used in one or more computers for wherein including computer usable program code
The computer program production that usable storage medium is implemented on (including but is not limited to magnetic disk storage, CD-ROM, optical memory etc.)
The form of product.
The application is the flow with reference to method, equipment (system) and computer program product according to the embodiment of the present application
Figure and/or block diagram are described.It should be understood that can be by every first-class in computer program instructions implementation process figure and/or block diagram
Journey and/or the flow in square frame and flow chart and/or block diagram and/or the combination of square frame.These computer programs can be provided
The processor of all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing devices is instructed to produce
A raw machine so that produced by the instruction of computer or the computing device of other programmable data processing devices for real
The device for the function of being specified in present one flow of flow chart or one square frame of multiple flows and/or block diagram or multiple square frames.
These computer program instructions, which may be alternatively stored in, can guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works so that the instruction being stored in the computer-readable memory, which is produced, to be included referring to
Make the manufacture of device, the command device realize in one flow of flow chart or multiple flows and/or one square frame of block diagram or
The function of being specified in multiple square frames.
These computer program instructions can be also loaded into computer or other programmable data processing devices so that in meter
Series of operation steps is performed on calculation machine or other programmable devices to produce computer implemented processing, thus in computer or
The instruction performed on other programmable devices is provided for realizing in one flow of flow chart or multiple flows and/or block diagram one
The step of function of being specified in individual square frame or multiple square frames.
Finally it should be noted that:The above embodiments are merely illustrative of the technical scheme of the present invention and are not intended to be limiting thereof, institute
The those of ordinary skill in category field with reference to above-described embodiment still can to the present invention embodiment modify or
Equivalent substitution, these any modifications or equivalent substitution without departing from spirit and scope of the invention are applying for this pending hair
Within bright claims.
Claims (16)
1. a kind of three-phase alternating voltage falls the determination methods of state, it is characterised in that the determination methods include:
Sampled voltage is changed to two-phase rotating coordinate system from three-phase static coordinate system;
Under the two-phase rotating coordinate system, isolated d axles DC voltage component U is decoupleddWith q axle DC voltage components Uq;
Using filtering the d axles DC voltage component UdWith q axle DC voltage components UqThe d axle DC voltage components obtained afterwards
UdfltWith q axle DC voltage components Uqflt, judge whether line voltage falls.
2. determination methods according to claim 1, it is characterised in that described under the two-phase rotating coordinate system, decoupling
Isolated d axles and q axle DC voltage component UdAnd Uq, specifically include:
As positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively θ0 PAnd θ0 N, the seat of positive sequence and negative sequence voltage
It is respectively θ to mark conversion angle0 PAnd θ0 NDuring -2 ω t, if rotating to be reference with positive sequence d axles and q axles, positive sequence DC voltage component is in d
The calculation formula of axle is as follows:
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Positive sequence DC voltage component is as follows in the calculation formula of q axles:
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Axis component,For the q axis components of negative sequence voltage vector.
3. determination methods according to claim 1, it is characterised in that described under the rotating coordinate system, decoupling separation
The d axles and q axis components of positive sequence voltage and negative sequence voltage are obtained, is specifically included:
As positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively θ0 PAnd θ0 N, the seat of positive sequence and negative sequence voltage
It is respectively θ to mark conversion angle0 P+ 2 ω t and θ0 NWhen, if rotating to be reference with negative phase-sequence d axles and q axles, negative phase-sequence DC voltage component is in d
The calculation formula of axle is as follows:
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<mrow>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>;</mo>
</mrow>
Negative phase-sequence DC voltage component is as follows in the calculation formula of q axles:
<mrow>
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>-</mo>
</msubsup>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<mi>sin</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>)</mo>
</mrow>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>;</mo>
</mrow>
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For the d of negative sequence voltage vector
Axis component,For the q axis components of negative sequence voltage vector.
4. the determination methods of the Voltage Drop state according to Claims 2 or 3, it is characterised in that further comprise:Institute
The component decoupling equation for stating d axles and q axles under two-phase rotating coordinate system is as follows:
<mrow>
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mo>+</mo>
</msubsup>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>+</mo>
</msubsup>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mo>-</mo>
</msubsup>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>-</mo>
</msubsup>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
<mo>;</mo>
</mrow>
WithIt is that Coordinate Conversion angle is θ respectively0 PAnd θ0 ND axle positive sequence DC voltage components and q axle positive sequences during -2 ω t is straight
Stream component of voltage,WithIt is that Coordinate Conversion angle is θ respectively0 P+ 2 ω t and θ0 NWhen d axle negative phase-sequence DC voltage components and q axles
Negative phase-sequence DC voltage component,For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector,It is negative
The d axis components of sequence voltage vector,For the q axis components of negative sequence voltage vector.
5. the determination methods of Voltage Drop state according to claim 4, it is characterised in that further comprise:
The d axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains d axles control component udr;
The q axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains q axles control component uqr。
6. the determination methods of Voltage Drop state according to claim 5, it is characterised in that further comprise:
D axle DC voltage components udWith q axles and DC voltage component uqCalculation formula is as follows:
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msub>
<mi>u</mi>
<mi>d</mi>
</msub>
<mo>=</mo>
<msub>
<mi>u</mi>
<mrow>
<mi>d</mi>
<mi>r</mi>
</mrow>
</msub>
<mo>+</mo>
<msubsup>
<mi>u</mi>
<mrow>
<mi>d</mi>
<mi>r</mi>
</mrow>
<mo>,</mo>
</msubsup>
<mo>-</mo>
<msub>
<mi>&Delta;u</mi>
<mrow>
<mi>d</mi>
<mi>r</mi>
</mrow>
</msub>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msub>
<mi>u</mi>
<mi>q</mi>
</msub>
<mo>=</mo>
<msub>
<mi>u</mi>
<mrow>
<mi>q</mi>
<mi>r</mi>
</mrow>
</msub>
<mo>+</mo>
<msubsup>
<mi>u</mi>
<mrow>
<mi>q</mi>
<mi>r</mi>
</mrow>
<mo>,</mo>
</msubsup>
<mo>-</mo>
<msub>
<mi>&Delta;u</mi>
<mrow>
<mi>q</mi>
<mi>r</mi>
</mrow>
</msub>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
In formula, u 'drWith u 'qrRespectively by the PI d axles adjusted and the output of q shaft currents ring, Δ udrWith Δ uqrRespectively d axles and q
The compensation term of shaft voltage.
7. the determination methods of Voltage Drop state according to claim 1, it is characterised in that described utilize filters the d
Axle DC voltage component UdWith the q axles DC voltage component UqThe U obtained afterwardsdfltAnd Uqflt, specifically include:
The d axles DC voltage component udWith the q axles DC voltage component uqLow-pass filtered device obtains udfltAnd uqflt。
8. the determination methods of Voltage Drop state according to claim 7, it is characterised in that the judgement line voltage is
It is no to fall, specifically include:
Interpretation is carried out to grid voltage sags flag bit with following formula, when
When, it is 1 to occur Voltage Drop power network to fall flag bit;
In formula,For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector, UdropFor preset value.
9. a kind of three-phase alternating voltage falls the judgement system of state, it is characterised in that the judgement system includes:
Modular converter, for sampled voltage to be changed to two-phase rotating coordinate system from three-phase static coordinate system;
Separation module is decoupled, under the two-phase rotating coordinate system, decoupling isolated d axles DC voltage component UdWith q axles
DC voltage component Uq;
Judge module, using filtering d axle DC voltage components UdWith q axle DC voltage components UqThe d axles DC voltage point obtained afterwards
Measure UdfltWith q axle DC voltage components Uqflt, judge whether line voltage falls.
10. judgement system according to claim 9, it is characterised in that the decoupling separation module, specifically for:
As positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively θ0 PAnd θ0 N, the seat of positive sequence and negative sequence voltage
It is respectively θ to mark conversion angle0 PAnd θ0 NDuring -2 ω t, if rotating to be reference with positive sequence d axles and q axles, positive sequence DC voltage component is in d
The calculation formula of axle is as follows:
<mrow>
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mo>+</mo>
</msubsup>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<mi>cos</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
<mo>-</mo>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>)</mo>
</mrow>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>;</mo>
</mrow>
Positive sequence DC voltage component is as follows in the calculation formula of q axles:
<mrow>
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>+</mo>
</msubsup>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<mi>sin</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
<mo>-</mo>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>)</mo>
</mrow>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>;</mo>
</mrow>
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For the d of negative sequence voltage vector
Axis component,For the q axis components of negative sequence voltage vector.
11. judgement system according to claim 9, it is characterised in that the decoupling separation module, specifically for:
As positive sequence voltage vector UPWith negative sequence voltage vector UNInitial angle be respectively θ0 PAnd θ0 N, the seat of positive sequence and negative sequence voltage
It is respectively θ to mark conversion angle0 P+ 2 ω t and θ0 NWhen, if rotating to be reference with negative phase-sequence d axles and q axles, negative phase-sequence DC voltage component is in d
The calculation formula of axle is as follows:
<mrow>
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mo>-</mo>
</msubsup>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<mi>cos</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>)</mo>
</mrow>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>;</mo>
</mrow>
Negative phase-sequence DC voltage component is as follows in the calculation formula of q axles:
<mrow>
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>-</mo>
</msubsup>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<mi>sin</mi>
<mrow>
<mo>(</mo>
<msubsup>
<mi>&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mo>+</mo>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>)</mo>
</mrow>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>P</mi>
</msup>
<msubsup>
<mi>cos&theta;</mi>
<mn>0</mn>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msup>
<mi>U</mi>
<mi>N</mi>
</msup>
<msubsup>
<mi>sin&theta;</mi>
<mn>0</mn>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
</mrow>
</mtd>
</mtr>
</mtable>
<mo>;</mo>
</mrow>
For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector;For the d of negative sequence voltage vector
Axis component,For the q axis components of negative sequence voltage vector.
12. the judgement system according to claim 10 or 11, it is characterised in that further comprise:
The component decoupling equation of d axles and q axles is as follows under the two-phase rotating coordinate system:
<mrow>
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mo>+</mo>
</msubsup>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>P</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>+</mo>
</msubsup>
<mo>+</mo>
<msubsup>
<mi>U</mi>
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<mn>2</mn>
<mi>&omega;</mi>
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<mo>-</mo>
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<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>N</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mo>-</mo>
</msubsup>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mi>cos</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>+</mo>
<msubsup>
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<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
<mtr>
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<msubsup>
<mi>U</mi>
<mi>q</mi>
<mi>N</mi>
</msubsup>
<mo>=</mo>
<msubsup>
<mi>U</mi>
<mi>q</mi>
<mo>-</mo>
</msubsup>
<mo>-</mo>
<msubsup>
<mi>U</mi>
<mi>d</mi>
<mi>P</mi>
</msubsup>
<mi>sin</mi>
<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
<mo>-</mo>
<msubsup>
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<mi>q</mi>
<mi>P</mi>
</msubsup>
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<mn>2</mn>
<mi>&omega;</mi>
<mi>t</mi>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
<mo>;</mo>
</mrow>
WithIt is that Coordinate Conversion angle is θ respectively0 PAnd θ0 ND axle positive sequence DC voltage components and q axle positive sequences during -2 ω t is straight
Stream component of voltage,WithIt is that Coordinate Conversion angle is θ respectively0 P+ 2 ω t and θ0 NWhen d axle negative phase-sequence DC voltage components and q axles
Negative phase-sequence DC voltage component,For the d axis components of positive sequence voltage vector,For the q axis components of positive sequence voltage vector,It is negative
The d axis components of sequence voltage vector,For the q axis components of negative sequence voltage vector.
13. judgement system according to claim 12, it is characterised in that further comprise:
The d axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains d axles control component Udr;
The q axis components superposition of positive sequence voltage vector negative sequence voltage vector obtains q axles control component Uqr。
14. judgement system according to claim 13, it is characterised in that further comprise:
D axle DC voltage components udWith q axle DC voltage components uqCalculation formula is as follows:
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msub>
<mi>u</mi>
<mi>d</mi>
</msub>
<mo>=</mo>
<msub>
<mi>u</mi>
<mrow>
<mi>d</mi>
<mi>r</mi>
</mrow>
</msub>
<mo>+</mo>
<msubsup>
<mi>u</mi>
<mrow>
<mi>d</mi>
<mi>r</mi>
</mrow>
<mo>,</mo>
</msubsup>
<mo>-</mo>
<msub>
<mi>&Delta;u</mi>
<mrow>
<mi>d</mi>
<mi>r</mi>
</mrow>
</msub>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msub>
<mi>u</mi>
<mi>q</mi>
</msub>
<mo>=</mo>
<msub>
<mi>u</mi>
<mrow>
<mi>q</mi>
<mi>r</mi>
</mrow>
</msub>
<mo>+</mo>
<msubsup>
<mi>u</mi>
<mrow>
<mi>q</mi>
<mi>r</mi>
</mrow>
<mo>,</mo>
</msubsup>
<mo>-</mo>
<msub>
<mi>&Delta;u</mi>
<mrow>
<mi>q</mi>
<mi>r</mi>
</mrow>
</msub>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
In formula, u 'drWith u 'qrRespectively by the PI d axles adjusted and the output of q shaft currents ring, Δ udrWith Δ uqrRespectively d axles and q
The compensation term of shaft voltage.
15. judgement system according to claim 9, it is characterised in that the judge module, specifically for:
The d axles DC voltage component udWith the q axles DC voltage component uqLow-pass filtered device obtains udfltAnd uqflt。
16. judgement system according to claim 15, it is characterised in that further comprise:
Interpretation is carried out to grid voltage sags flag bit with following formula, when
When, it is 1 to occur Voltage Drop power network to fall flag bit;
In formula,For positive sequence voltage d axis components,For positive sequence voltage q axis components, UdropFor preset value.
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