CN106655270B - Inhibit the control method of three-phase LCL type grid-connection converter rectification inrush current - Google Patents
Inhibit the control method of three-phase LCL type grid-connection converter rectification inrush current Download PDFInfo
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- CN106655270B CN106655270B CN201611244846.5A CN201611244846A CN106655270B CN 106655270 B CN106655270 B CN 106655270B CN 201611244846 A CN201611244846 A CN 201611244846A CN 106655270 B CN106655270 B CN 106655270B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/36—Means for starting or stopping converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
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Abstract
The invention discloses a kind of control methods of inhibition three-phase LCL type grid-connection converter rectification inrush current, and the control method can also make system have preferable stability under weak grid.Side filter capacitor voltage is exchanged by detection, as the synchronizing voltage for decoupling double synchronous plls, double synchronous pll output filter capacitor voltage d axis fundamental positive sequences are decoupled to increase in grid-connection converter electric current loop with filter capacitor voltage together as feed-forward component.To improve LCL type grid-connection converter starting control performance, and system is made also to be able to maintain stronger robustness under weak grid.The present invention does not increase sampling quantity, does not increase hardware cost, do not increase the computation burden of system on the basis of traditional three-phase LCL type grid-connection converter current control method.
Description
Technical field
The invention belongs to new energy grid-connected power technical field, a kind of inhibition three-phase LCL type grid-connection converter rectification starting
The control method of dash current, and the control method can also make system have preferable stability under weak grid.
Background technique
With the raising of new-energy grid-connected permeability, stringent grid-connected directive/guide has all been formulated in various countries and area in succession, to simultaneously
More stringent requirements are proposed for the control performance of net transformation device.For LCL type grid-connection converter, rectification can generate serious when starting
Dash current, if will lead to protection act, or even damage switching device without suitable suppressing method.
Currently, grid-connection converter inrush current Restrain measurement is broadly divided into following two categories.One kind is change starting electricity
Stream instruction, but when starting, power network current is not by the control of current-order, even if current-order is zero, when starting still can
Generate serious dash current.This method not only cannot fundamentally inhibit inrush current, can reduce electric current loop instead
Starting response speed.Another kind of is to inhibit inrush current using point of common coupling (PCC) electric voltage feed forward.However weak
Off the net, PCC electric voltage feed forward, which is equivalent to, introduces a positive feedback about electric network impedance, can make to generate in power network current a large amount of humorous
It is unstable to even result in system for wave.
In actual megawatt-level wind system, grid-connection converter is generally connected to 10kV or higher voltage class,
The voltage of step down side can only be acquired.And for LCL type grid-connection converter, transformer leakage inductance is generally as LCL filter
Net side inductance, thus it is possible to acquisition only filter capacitor voltage.
Summary of the invention
The present invention provides a kind of control methods of inhibition three-phase LCL type grid-connection converter rectification inrush current, and
And the control method can also make system have preferable stability under weak grid.Side filter capacitor voltage is exchanged by detection,
As the synchronizing voltage for decoupling double synchronous plls, double synchronous pll output filter capacitor voltage d axis fundamental positive sequences point are decoupled
Amount, with filter capacitor voltage together as feed-forward component, increases in grid-connection converter electric current loop.To improve LCL type simultaneously
Net transformation device starts control performance, and system is made also to be able to maintain stronger robustness under weak grid.
The present invention provides a kind of control method of inhibition three-phase LCL type grid-connection converter rectification inrush current, packets
Include following steps:
(1) the three-phase LCL type grid-connection converter DC voltage U is obtaineddc, three phase capacitance voltage Ucabc, three-phase grid
Electric current I2abcWith three phase capacitance electric current Icabc；
(2) DC voltage is instructedSubtract the DC voltage UdcDirect current voltage error signal U is obtained afterwardsedc, and
To the direct current voltage error signal UedcThe instruction of d axis grid-connected current is obtained after carrying out closed-loop process
To the three phase capacitance voltage UcabcIt carries out decoupling double genlock processing, obtains the three phase capacitance voltage Ucabc
Phase angle theta and capacitance voltage d axis fundamental positive sequenceAccording to the phase angle theta to the three-phase grid electric current I2abcIt carries out
The d axis grid-connected current I under synchronous rotating frame is obtained after abc/dq coordinate transform2d, q axis grid-connected current I2q；
To the three phase capacitance electric current Icabc, three phase capacitance voltage UcabcAbc/ α β coordinate transform is carried out respectively, obtains two-phase
α axis capacitance current I under rest framecα, β axis capacitance current Icβ, α axis capacitance voltage Ucα, β axis capacitance voltage Ucβ；
(3) given q axis grid-connected current is instructedWith the q axis grid-connected current I2qSubtract each other and obtains q axis grid-connected current mistake
Poor I2eq, and to the q axis grid-connected current error I2eqClosed-loop process is carried out, q axis is obtained and controls voltage U 'rq；
The d axis grid-connected current is instructedWith d axis grid-connected current I2dSubtract each other and obtains d axis grid-connected current error I2ed；And
To the d axis grid-connected current error I2edClosed-loop process is carried out, d axis is obtained and controls voltage U 'rd；
(4) voltage U ' is controlled to the d axis according to the phase angle thetardVoltage U ' is controlled with the q axisrqDq/ α β is carried out to sit
Mark transformation obtains the α axis under two-phase stationary coordinate system and controls voltage U 'rα, β axis control voltage U 'rβ；
According to the phase angle theta to the capacitance voltage d axis fundamental positive sequenceDq/ α β coordinate transform is carried out, electricity is obtained
Hold voltage α axis fundamental positive sequenceCapacitance voltage β axis fundamental positive sequence
(5) voltage U ' is controlled according to the α axisrα, β axis control voltage U 'rβ, capacitance voltage α axis fundamental positive sequenceCapacitance voltage β axis fundamental positive sequenceThe α axis capacitance voltage Ucα, β axis capacitance voltage Ucβ, α axis capacitance current
IcαWith β axis capacitance current IcβObtain α axis modulation voltage Urα, β axis modulation voltage Urβ；
(6) to the α axis modulation voltage UrαWith β axis modulation voltage UrβSpace vector pulse width modulation is carried out, grid-connected change is obtained
The switch control signal of parallel operation.
Further, in step (2), the calculation formula of the capacitance voltage d axis fundamental positive sequence is obtained are as follows:Wherein, ωfFor the cut-off angular frequency for decoupling low-pass filter in double synchronous plls
Rate, ω0For power grid fundamental wave frequency, s is complex variable,For the d axis fundamental positive sequence of capacitance voltageLaplace
Transformation, UcdIt (s) is d axis capacitance voltage UcdLaplace transformation.
Further, in step (5), according to formula
Obtain α axis modulation voltage Urα, β axis modulation voltage Urβ；
Wherein, KcpFor capacitor current feedback proportionality coefficient, K1fFor capacitance voltage fundamental positive sequence feedover proportionality coefficient,
K2fIt feedovers proportionality coefficient for capacitance voltage, and K1f+K2f=1.
The present invention also provides a kind of three-phase LCL type grid-connection converter systems, comprising: main circuit and control circuit, it is special
Sign is, the control circuit include: direct-current voltage control unit, space vector pulse width modulation device, power network current control unit,
Decouple double synchronous plls and inrush current suppressor；The input terminal for decoupling double synchronous plls is connected to main circuit
Capacitance voltage output end, the first input end of inrush current suppressor, which is connected to, described decouples the of double synchronous plls
One output end, the second input terminal of inrush current suppressor are connected to second output for decoupling double synchronous plls
End, the third input terminal of inrush current suppressor are connected to the first output end of the power network current control unit, start
4th input terminal of dash current suppressor is connected to the second output terminal of the power network current control unit, inrush current
5th input terminal of suppressor is connected to the input terminal for decoupling double synchronous plls, and the first of the power network current control unit is defeated
Enter end and be connected to the second output terminal for decoupling double synchronous plls, the second input terminal of the power network current control unit connects
It is connected to the power network current output end of main circuit, the third input terminal of the power network current control unit is connected to DC voltage control
4th input terminal of the output end of unit, the power network current control unit is connected to the capacitance current output end of main circuit, institute
The input terminal for stating direct-current voltage control unit is connected to the DC voltage output end of main circuit；The space vector pulse width modulation device
Input terminal be connected to the output end of inrush current suppressor, the output end of space vector pulse width modulation device is connected to described
The feedback control end of main circuit simultaneously is used to provide switch control signal.
Further, inrush current suppressor includes: the first converter, the second converter, the first proportionality coefficient
Generator, the second proportionality coefficient generator, third proportionality coefficient generator, the 4th proportionality coefficient generator, first adder,
Two adders, third adder and the 4th adder；The first input end of first converter presses down as inrush current
The first input end of device processed, the second input terminal of first converter for receiving 0, make by the third input terminal of the first converter
For the second input terminal of the inrush current suppressor；The input terminal of first proportionality coefficient generator is connected to described first
The input terminal of first output end of converter, the second proportionality coefficient generator is connected to the second output terminal of the first converter；The
The input terminal of two converters is connected to the input terminal for decoupling double synchronous plls, the input terminal connection of third proportionality coefficient generator
To the first output end of the second converter, the input terminal of the 4th proportionality coefficient generator is connected to the second output of the second converter
End；The first input end of first adder is connected to the output end of the first proportionality coefficient generator, and the of first adder
Two input terminals are connected to the output end of the third proportionality coefficient generator, and the first input end of second adder is connected to described
The output end of second proportionality coefficient generator, the second input terminal of second adder are connected to the 4th proportionality coefficient generator
Output end；The first input end of third adder is connected to the output end of the first adder, and the second of third adder
Third input terminal of the input terminal as the inrush current suppressor；The first input end of 4th adder is connected to described
The output end of second adder, fourth input terminal of the second input terminal of the 4th adder as inrush current suppressor；
The output end of the output end of third adder and the output end of the 4th adder as the inrush current suppressor.
Further, the first converter is used for according to phase angle theta to capacitance voltage d axis fundamental positive sequenceCarry out dq/
α β coordinate transform obtains capacitance voltage α axis fundamental positive sequenceCapacitance voltage β axis fundamental positive sequenceDescribed
Two converters are used for three phase capacitance voltage UcabcAbc/ α β coordinate transform is carried out, the α axis electricity under two-phase stationary coordinate system is obtained
Hold voltage Ucα, β axis capacitance voltage Ucβ。
In general, above-mentioned technical concept according to the invention compared with prior art, it is excellent mainly to have technology below
Point:
(1) present invention is more suitable for that the MW class LCL type grid-connection converter of filter capacitor voltage can only be acquired.
(2) the mentioned control method of the present invention does not influence the stability of original electric current loop；
(3) the mentioned control method of the present invention can also make system have preferable stability under weak grid；
(4) capacitance voltage needed for the mentioned control method of the present invention is the synchronizing voltage as the double synchronous plls of decoupling,
Required capacitance voltage fundamental positive sequence is to decouple the output of double synchronous plls, in traditional three-phase LCL type grid-connection converter
On the basis of current control method, do not increase sampling quantity, do not increase hardware cost, does not increase the computation burden of system.
Detailed description of the invention
Fig. 1 is three-phase LCL type grid-connection converter structural block diagram proposed by the present invention and rectification inrush current inhibition side
Method functional block diagram；
Fig. 2 is to decouple double synchronous pll control block diagrams；
Fig. 3 is power network current ring d axis control block diagram；
Fig. 4 is grid-connection converter output impedance Bode diagram under different grid short circuits when different control programs；
Fig. 5 is not use dash current Restrain measurement, grid-connection converter rectification starting emulation wave when power grid inductance is 0
Shape；
Fig. 6 is when power grid inductance is 0, and capacitance voltage directly feedover dash current Restrain measurement, and grid-connection converter rectifies
Start simulation waveform；
Fig. 7 is the dash current Restrain measurement provided by the invention when power grid inductance is 0, grid-connection converter rectification starting
Simulation waveform；
Fig. 8 is as grid short circuit ratio SCR=2, and capacitance voltage directly feedovers dash current Restrain measurement, grid-connection converter
Rectification starting simulation waveform；
Fig. 9 is the dash current Restrain measurement provided by the invention as grid short circuit ratio SCR=2, grid-connection converter rectification
Start simulation waveform.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.As long as in addition, technical characteristic involved in the various embodiments of the present invention described below
Not constituting a conflict with each other can be combined with each other.
The present invention take effective control program inhibit LCL type grid-connection converter rectify inrush current, and
It is weak it is off the net can also make system have preferable stability.
Three-phase LCL type grid-connection converter structural block diagram provided by the present invention and rectification inrush current suppressing method are former
Managing block diagram, three-phase LCL type grid-connection converter system includes: direct-current voltage control unit 1, grid-connection converter and LCL as shown in Figure 1:
Filter 2, space vector pulse width modulation device 4, power network current control unit 5, decouples double synchronous plls 6 and opens public electric wire net 3
Dynamic dash current suppressor 7；Wherein, DC voltage control generally uses pi controller in direct-current voltage control unit 1；
LCL filter is by transducer side filter inductance L in grid-connection converter and LCL filter 21, filter capacitor CfAnd transformer leakage inductance
LTComposition；Public electric wire net 3 is by power grid inductance LgWith network voltage source UgComposition；Capacitance current is anti-in power network current control unit 5
The active damping for realizing LCL filter is presented, power network current closed-loop control generally uses pi controller.
The control method packet provided in an embodiment of the present invention for inhibiting three-phase LCL type grid-connection converter rectification inrush current
Include following step:
(1) the three-phase LCL type grid-connection converter DC voltage U is obtained by voltage, current Hall sensordc、
Three phase capacitance voltage Ucabc, three-phase grid electric current I2abcWith three phase capacitance electric current Icabc；
(2) according to the DC voltage U in step (1)dcIt is instructed with DC voltageSubtract each other to obtain direct current
Hold up difference signal Uedc, its calculation formula is:
(3) by DC voltage controller come to the direct current voltage error signal UedcClosed-loop process is carried out, d axis is obtained
Grid-connected current instruction
(4) double synchronous pll control block diagrams are decoupled as shown in Fig. 2, obtaining described three using double synchronous plls are decoupled
Phase capacitance voltage UcabcPhase angle theta and capacitance voltage d axis fundamental positive sequence
(5) according to the phase angle theta in step (4), to the three-phase grid electric current I in above-mentioned steps (1)2abcCarry out abc/
Dq coordinate transform, to obtain the d axis grid-connected current I under synchronous rotating frame2d, q axis grid-connected current I2q；
(6) the q axis grid-connected current I according to step (5)2q, the d axis grid-connected current I2dRespectively with q axis grid-connected current
InstructionD axis grid-connected current instructs in above-mentioned steps (3)Subtract each other to obtain q axis grid-connected current error I2eq, the grid-connected electricity of d axis
Stream error I2ed, its calculation formula is:
(7) by current controller come to d axis grid-connected current error I described in step (6)2ed, the q axis grid-connected current
Error I2eqClosed-loop process is carried out, d axis, q axis control voltage U ' are obtainedrd、U′rq；
(8) according to the phase angle theta in step (4), voltage U ' is controlled to d axis described in above-mentioned steps (7)rd, q axis control voltage
U′rq, capacitance voltage d axis fundamental positive sequence described in above-mentioned steps (4)Dq/ α β coordinate transform is carried out, respectively to obtain
α axis under two-phase stationary coordinate system controls voltage U 'rα, β axis control voltage U 'rβ, capacitance voltage α axis fundamental positive sequence
Capacitance voltage β axis fundamental positive sequence
(9) to the three phase capacitance electric current I in above-mentioned steps (1)cabc, three phase capacitance voltage UcabcAbc/ α is carried out respectively
β coordinate transform, to obtain the α axis capacitance current I under two-phase stationary coordinate systemcα, β axis capacitance current Icβ, α axis capacitance voltage Ucα、
β axis capacitance voltage Ucβ；
(10) voltage U ' is controlled according to α axis in above-mentioned steps (8)rα, β axis control voltage U 'rβ, capacitance voltage α axis fundamental wave just
Order componentsCapacitance voltage β axis fundamental positive sequenceα axis capacitance voltage U described in step (9)cα, β axis capacitor electricity
Press Ucβ, α axis capacitance current Icα, β axis capacitance current Icβ, α axis, β axis modulation voltage U are obtained to calculaterα、Urβ, calculation formula
Are as follows:Wherein KcpFor capacitor current feedback proportionality coefficient, capacitor electricity
Stream feeds back the resonance peak for inhibiting LCL filter, K1fFor capacitance voltage fundamental positive sequence feedforward proportionality coefficient, K2fFor electricity
Hold electric voltage feed forward proportionality coefficient, chooses K1f+K2fThe adjustable inrush current of size inhibitory effect, K1f+K2fIt is bigger,
Dash current inhibitory effect is better, K1f+K2fSmaller, dash current inhibitory effect is poorer, generally takes K1f+K2f=1, work as K1f+K2f
When=1, increase K1fAnd reduce K2f, system can be made weak off the net with preferable stability, increase K2fAnd reduce K1f, can
Keep strong system off the net stronger to power grid background harmonics rejection ability, the present invention chooses K1f=1, K2f=0；
(11) to α axis, the β axis modulation voltage U in step (10)rα、UrβSpace vector pulse width modulation is carried out, to obtain simultaneously
The switching signal S of net transformation device three pairs of switching pipea、Sb、Sc。
(12) in step (4), the meter that double synchronous plls obtain the capacitance voltage d axis fundamental positive sequence is decoupled
Calculate formula are as follows:Wherein ω0For power grid fundamental wave frequency, ωfIt is double synchronous to decouple
The cut-off angular frequency of low-pass filter, usually takes ω in phaselocked loopf=0.707 ω0, s is complex variable,For capacitance voltage
D axis fundamental positive sequenceLaplace transformation, UcdIt (s) is d axis capacitance voltage UcdLaplace transformation, this calculating process be decoupling
Double synchronous pll inherent characteristics, are completed inside phaselocked loop.
It is one embodiment of the mentioned method of the present invention below:
For the present invention by taking the directly driven wind-powered LCL type grid-connection converter of 10kW as an example, system parameter is as shown in table 1:
1 grid-connection converter system parameter of table
| Parameter | Value | Parameter | Value |
| Grid line voltage Ugl | 380V | DC voltage Udc | 650V |
| Mains frequency fg | 50Hz | Transducer side filter inductance L1 | 3.2mH |
| Transformer voltage ratio N | 380/340 | Filter capacitor Cf | 15μF |
| Switching frequency fsw | 4.8kHz | Transformer leakage inductance LT | 0.85mH |
| Sample frequency fs | 9.6kHz | Capacitor current feedback COEFFICIENT Kcp | 18 |
Power network current ring d axis control block diagram provided by the present invention is as shown in Figure 3: whereinFor power network current d axis
Instruction, GiIt (s) is power network current ring pi controller, its calculation formula is:GdeIt (s) is control
Be delayed transmission function, its calculation formula isWherein TsFor sampling period, KcpFor capacitor
Current feedback proportionality coefficient, L1For transducer side filter inductance, CfFor filter capacitor, LTFor transformer leakage inductance, L'gFor through transformation
Power grid inductance after device conversion, UcdIt (s) is d axis capacitance voltage, U 'gdIt (s) is the d axis network voltage after transformer is converted, I2d
It (s) is d axis power network current, GfIt (s) is front feeding transfer function, its calculation formula is:
According to Fig. 3, different grid short circuits when grid-connection converter output impedance Bode diagram under different control programs can be obtained,
It is as shown in Figure 4: wherein K1f=0, K2f=0 is not use inrush current Restrain measurement, K1f=0, K2f=1 is capacitance voltage
Directly feedover dash current Restrain measurement, K1f=1, K2f=0 is dash current Restrain measurement provided by the present invention, and SCR is electricity
Net circuit ratio, SCR is smaller to show that power grid is weaker, sL 'gFor the electric network impedance after transformer is converted.PMcrossRepresent weak system off the net
The stability margin of system, PMcross> 0 represents system and stablizes, and PMcrossBigger, the weak stability off the net of system is better.
As shown in figure 4, weak off the net, when non-impact current Restrain measurement, system has enough stability margins, PMcrossAlways
Serious dash current can be generated when being positive, but starting.Directly feedovered using capacitance voltage dash current Restrain measurement when, become
Parallel operation output impedance low-frequency range amplitude increases, and illustrates that system has the ability for inhibiting network voltage low frequency background harmonics.But phase is big
Width reduces, and the characteristic of negative impedance, PM is presentedcrossIt is negative, system is unstable.Also, power grid is weaker, PMcrossIt is smaller, system
Stability is poorer.In dash current Restrain measurement provided by the present invention, converter output impedance amplitude and phase with do not use
Close, PM when dash current Restrain measurementcrossIt is 45 °, system still has enough stability margins.So provided by the present invention
Scheme off the net have better robustness weak.
If Fig. 5, Fig. 6, Fig. 7 are shown when power grid inductance is 0, do not use dash current Restrain measurement, capacitance voltage straight
Feedforward dash current Restrain measurement and dash current Restrain measurement provided by the present invention are connect, grid-connection converter rectification starting is imitated
True result.
In Fig. 5, when not using dash current Restrain measurement, when starting, power network current peak value reaches 40A (overshoot 167%).
Obviously, such dash current can cause protection act, then generate serious mechanical stress, damage switching device.Work as addition
After dash current Restrain measurement, as shown in Figure 6 and Figure 7, after of short duration adjustment process, grid-connected current is without significant overshoot
Stable state is converged to, current spike has obtained effective inhibition.
As shown in Figure 8 and Figure 9 for as grid short circuit ratio SCR=2, the dash current that directly feedovered using capacitance voltage is inhibited
Scheme and dash current Restrain measurement provided by the present invention, grid-connection converter rectification starting simulation result.It is weak off the net, capacitor electricity
No enough stability margins that directly feedover are pressed, there are a large amount of harmonic waves, Severe distortions for power network current waveform.And it is provided by the present invention
Dash current Restrain measurement it is minimum to the stability influence of system, grid-connected current have good waveform quality.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should all include
Within protection scope of the present invention.
Claims (5)
1. it is a kind of inhibit three-phase LCL type grid-connection converter rectification inrush current control method, which is characterized in that including with
Lower step:
(1) the three-phase LCL type grid-connection converter DC voltage U is obtaineddc, three phase capacitance voltage Ucabc, three-phase grid electric current
I2abcWith three phase capacitance electric current Icabc；
(2) DC voltage is instructedSubtract the DC voltage UdcDirect current voltage error signal U is obtained afterwardsedc, and to institute
State direct current voltage error signal UedcThe instruction of d axis grid-connected current is obtained after carrying out closed-loop process
To the three phase capacitance voltage UcabcIt carries out decoupling double genlock processing, obtains the three phase capacitance voltage UcabcPhase
The d axis fundamental positive sequence of angle θ and capacitance voltageAccording to the phase angle theta to the three-phase grid electric current I2abcCarry out abc/
The d axis grid-connected current I under synchronous rotating frame is obtained after dq coordinate transform2d, q axis grid-connected current I2q；
To the three phase capacitance electric current Icabc, three phase capacitance voltage UcabcAbc/ α β coordinate transform is carried out respectively, and it is static to obtain two-phase
α axis capacitance current I under coordinate systemcα, β axis capacitance current Icβ, α axis capacitance voltage Ucα, β axis capacitance voltage Ucβ；
(3) given q axis grid-connected current is instructedWith the q axis grid-connected current I2qSubtract each other and obtains q axis grid-connected current error
I2eq, and to the q axis grid-connected current error I2eqClosed-loop process is carried out, q axis is obtained and controls voltage U 'rq；
The d axis grid-connected current is instructedWith d axis grid-connected current I2dSubtract each other and obtains d axis grid-connected current error I2ed；And to institute
State d axis grid-connected current error I2edClosed-loop process is carried out, d axis is obtained and controls voltage U 'rd；
(4) voltage U ' is controlled to the d axis according to the phase angle thetardVoltage U ' is controlled with the q axisrqCarry out dq/ α β coordinate transform
The α axis obtained under two-phase stationary coordinate system controls voltage U 'rα, β axis control voltage U 'rβ；
According to the phase angle theta to the capacitance voltage d axis fundamental positive sequenceDq/ α β coordinate transform is carried out, capacitor electricity is obtained
Press α axis fundamental positive sequenceCapacitance voltage β axis fundamental positive sequence
(5) voltage U ' is controlled according to the α axisrα, β axis control voltage U 'rβ, capacitance voltage α axis fundamental positive sequenceCapacitor
Voltage β axis fundamental positive sequenceThe α axis capacitance voltage Ucα, β axis capacitance voltage Ucβ, α axis capacitance current IcαWith β axis electricity
Capacitance current IcβObtain α axis modulation voltage Urα, β axis modulation voltage Urβ；
(6) to the α axis modulation voltage UrαWith β axis modulation voltage UrβSpace vector pulse width modulation is carried out, grid-connection converter is obtained
Switch control signal.
2. control method as described in claim 1, which is characterized in that in step (2), obtain the capacitance voltage d axis base
The calculation formula of wave positive-sequence component are as follows:
Wherein, ωfFor the cut-off angular frequency for decoupling low-pass filter in double synchronous plls, ω0For power grid fundamental wave frequency, s is
Complex variable,For the d axis fundamental positive sequence of capacitance voltageLaplace transformation, UcdIt (s) is d axis capacitance voltage Ucd
Laplace transformation.
3. control method as claimed in claim 1 or 2, which is characterized in that in step (5), according to formulaObtain α axis modulation voltage Urα, β axis modulation voltage Urβ；
Wherein, KcpFor capacitor current feedback proportionality coefficient, K1fFor capacitance voltage fundamental positive sequence feedforward proportionality coefficient, K2fFor
Capacitance voltage feedforward proportionality coefficient, and K1f+K2f=1.
4. a kind of three-phase LCL type grid-connection converter system, comprising: main circuit and control circuit, which is characterized in that the control electricity
Road includes: that direct-current voltage control unit (1), space vector pulse width modulation device (4), power network current control unit (5), decoupling are double same
Walk phaselocked loop (6) and inrush current suppressor (7)；
The input terminal for decoupling double synchronous plls (6) is connected to the capacitance voltage output end of main circuit, inrush current
The first input end of suppressor (7) is connected to first output end for decoupling double synchronous plls (6), inrush current suppression
Second input terminal of device (7) processed is connected to the second output terminal for decoupling double synchronous plls (6), and inrush current inhibits
The third input terminal of device (7) is connected to the first output end of the power network current control unit (5), inrush current suppressor
(7) the 4th input terminal is connected to the second output terminal of the power network current control unit (5), inrush current suppressor
(7) the 5th input terminal is connected to the input terminal for decoupling double synchronous plls (6)；The of the power network current control unit (5)
One input terminal is connected to the second output terminal for decoupling double synchronous plls (6), and the of the power network current control unit (5)
Two input terminals are connected to the power network current output end of main circuit, the third input terminal connection of the power network current control unit (5)
To the output end of direct-current voltage control unit (1), the 4th input terminal of the power network current control unit (5) is connected to main circuit
Capacitance current output end, the input terminal of the direct-current voltage control unit (1) is connected to the DC voltage output end of main circuit；
The input terminal of the space vector pulse width modulation device (4) is connected to the output end of the inrush current suppressor (7),
The output end of the space vector pulse width modulation device (4) is connected to the feedback control end of the main circuit and for providing switch control
Signal processed；
The inrush current suppressor (7) includes: the first converter, the second converter, the first proportionality coefficient generator,
Two proportionality coefficient generators, third proportionality coefficient generator, the 4th proportionality coefficient generator, first adder, second adder,
Third adder and the 4th adder；
First input end of the first input end of first converter as the inrush current suppressor (7), it is described
For second input terminal of the first converter for receiving 0, the third input terminal of first converter impacts electricity as the starting
Flow second input terminal of suppressor (7)；
The input terminal of the first proportionality coefficient generator is connected to the first output end of first converter, second ratio
The input terminal of example coefficient producer is connected to the second output terminal of first converter；
The input terminal of second converter is connected to the input terminal for decoupling double synchronous plls (6), the third ratio
The input terminal of coefficient producer is connected to the first output end of second converter, the 4th proportionality coefficient generator it is defeated
Enter the second output terminal that end is connected to second converter；
The first input end of first adder is connected to the output end of the first proportionality coefficient generator, and the of first adder
Two input terminals are connected to the output end of the third proportionality coefficient generator, and the first input end of second adder is connected to described
The output end of second proportionality coefficient generator, the second input terminal of second adder are connected to the 4th proportionality coefficient generator
Output end；
The first input end of third adder is connected to the output end of the first adder, the second input terminal of third adder
Third input terminal as the inrush current suppressor (7)；
The first input end of 4th adder is connected to the output end of the second adder, the second input terminal of the 4th adder
The 4th input terminal as the inrush current suppressor (7)；
The output end of the third adder and the output end of the 4th adder are as the inrush current suppressor
(7) output end.
5. three-phase LCL type grid-connection converter system as claimed in claim 4, which is characterized in that first converter is used for
According to phase angle theta to capacitance voltage d axis fundamental positive sequenceDq/ α β coordinate transform is carried out, is obtaining capacitance voltage α axis fundamental wave just
Order componentsCapacitance voltage β axis fundamental positive sequence
Second converter is used for three phase capacitance voltage UcabcAbc/ α β coordinate transform is carried out, two-phase stationary coordinate system is obtained
Under α axis capacitance voltage Ucα, β axis capacitance voltage Ucβ。
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| CN108365628B (en) * | 2018-03-12 | 2022-01-14 | 固德威技术股份有限公司 | Three-phase photovoltaic grid-connected inverter non-impact current grid-connected control method |
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| CN102290820A (en) * | 2011-08-22 | 2011-12-21 | 中国矿业大学 | LCL (Lower Control Unit) filtering controlled rectifying active damping control method of electric currents on feedback variable current side |
| CN103475029A (en) * | 2013-09-27 | 2013-12-25 | 重庆大学 | Three-phase LCL type grid-connected inverter control system and method based on pole assignment |
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| CN102290820A (en) * | 2011-08-22 | 2011-12-21 | 中国矿业大学 | LCL (Lower Control Unit) filtering controlled rectifying active damping control method of electric currents on feedback variable current side |
| CN103475029A (en) * | 2013-09-27 | 2013-12-25 | 重庆大学 | Three-phase LCL type grid-connected inverter control system and method based on pole assignment |
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