CN102969735B - Photovoltaic flexibility grid-connection device and control method - Google Patents
Photovoltaic flexibility grid-connection device and control method Download PDFInfo
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- 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
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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- 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
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
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- 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
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
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Abstract
The invention discloses a photovoltaic flexibility grid-connection device and a control method. The photovoltaic flexibility grid-connection device comprises a support capacitance module, a voltage detection module, a program-controlled computer (PCC) module, a current detection module, a controller module, a pulse-width modulation (PWM) pulse generation module and a contravariant module. Voltage signals collected by the voltage detection module from two ends of the support capacitance module and power grid current signals of the PCC module collected by the current detection module serve as input signals of the controller module, outputs signals of the controller module serve as input signals of the PWM pulse generation module, pulse signals generated by the PWM pulse generation module are input in the contravariant module to control output of the contravariant module. The photovoltaic flexibility grid-connection device and the control method can achieve harmonic suppression and reactive compensation, can reduce impacts of load sudden change on the power grid, improve quality of photovoltaic system grid-connection current, have characteristics of the friendly power grid and are simple in control method.
Description
Technical field
The present invention relates to a kind of photovoltaic flexibility grid-connection device and control method.
Background technology
In traditional energy shortage with under the increasingly serious situation of problem of environmental pollution, the extensive concern that the research and development of new forms of energy obtain, solar energy becomes the new forms of energy of most development potentiality with its many merits.
Photovoltaic power generation grid-connecting technology, to be fed to active energy to bulk power grid, the direct current energy inversion of photovoltaic module is AC energy by system, is fed to bulk power grid by PCC (point of common coupling, Point of Common Coupling).Flexibility is grid-connected is in photovoltaic power generation grid-connecting process, can realize harmonics restraint and reactive power compensation, can reduce a kind of synchronizing mode of load changing to the impact of electrical network.
There is new change in electrical network and the load structure of electric power system in the present age, the use of the application of power electronics new technology, the high-tech device of various sensitivity have impact on the electrical network quality of power supply.The use of a large amount of nonlinear load in electric power system, causes electrical network particularly to decline away from the electrical network tip quality of power supply of load center, and produces and humorously involve the problems such as idle, rush of current.At present, to the suppression of mains by harmonics and reactive current, in grid-connected system, harmonic inhabitation electric current and compensating reactive power electric current can be come in conjunction with APF function.But the APF based on harmonic detecting technique controls, need load current and inverter output current testing circuit, need to calculate harmonic current and reactive current, the compensation effect of the Accuracy system of harmonics and reactive current detection technology and dynamic.Meanwhile, it is large that current detection technique has amount of calculation, and calculation of complex or use low pass filter affect the shortcoming of dynamic.
Figure 1 shows that photovoltaic parallel in system structure chart of the prior art.Photovoltaic cell 10 provides direct current, by flexibility grid-connection device 20, is alternating voltage by direct voltage inversion; Load 30 is as harmonic source, and produce and humorously involve reactive current, it is connected with photovoltaic flexibility grid-connection device, is then connected to electrical network 40 by PCC.
In sum, the humorous of current photovoltaic parallel in system involves reactive power compensation implementation method all to detect based on load current and inverter output current, detection harmonic current and reactive current, use current sensor is more, compensation effect is limited to the detection method of harmonic current and reactive current, the problem using and realize the flexible grid-connected those skilled in the art of being of photovoltaic to need to solve of the transducer that therefore how to omit harmonics and reactive current detection technology, simplifies control strategy, reduces.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of photovoltaic flexibility grid-connection device and control method, this photovoltaic flexibility grid-connection device and control method can realize harmonics restraint and reactive power compensation, the impact that load changing brings electrical network can be reduced, improve the quality of photovoltaic system grid-connected current, there is electrical network complimentary nature, and control method is simple.
The technical solution of invention is as follows:
A kind of photovoltaic flexibility grid-connection device, comprising: support capacitance module, voltage detection module, PCC module, current detection module, controller module, pwm pulse generation module and inversion module;
The DC side parallel of support capacitance module and inversion module; The output side joint PCC module of inversion module; Described inversion module is three-phase bridge type converter;
The voltage signal at the support capacitance module two ends gathered by voltage detection module and the power network current signal of PCC module gathered by current detection module, as the input signal of controller module, the output signal of controller module is as the input signal of pwm pulse generation module, the pulse signal that pwm pulse generation module produces is input to inversion module, controls the output of inversion module;
Photovoltaic flexibility grid-connection device is connected with load with electrical network by described PCC module.
Described current detection module is current Hall transducer.
Described voltage detection module is voltage hall sensor.
Described controller module comprises voltage controller and current controller;
Described voltage controller, electrical network instruction current is produced based on voltage instruction value and DC voltage, output variable is as the input of current controller, and described voltage instruction value is the magnitude of voltage selected by tracing maximum power of photovoltaic cell control or system desired volume;
Described current controller, control based on electrical network instruction current and electrical network actual current, make power network current follow the tracks of electrical network instruction current, control power network current signal only containing the active component of current, the Output rusults of current controller is as the input of described pwm pulse generation module.
The flexible grid-connected control method of photovoltaic based on aforementioned photovoltaic flexibility grid-connection device, is characterized in that, adopt the double circle controling mode based on voltage and current, that is:
Gather the voltage of Support Capacitor and the power network current at PCC module place;
Outer shroud is voltage control loop, the command voltage of outer loop sets and virtual voltage is compared the difference obtained and is input to voltage controller, and voltage controller output valve is instruction current;
Inner ring is current regulator, and instruction current and actual electric network current ratio are input to current controller compared with the difference of gained, and current controller Output rusults, as the input of described pwm pulse generation module, makes power network current i
sfollow the tracks of electrical network instruction current
control power network current only containing the active component of current, i.e. electrical network instruction current
equal load current fundamental active component i
lfactive current i available with photovoltaic cell
cfsum, namely
Voltage controller is pi regulator, the pi regulator ratio value coefficient k of this device
p=0.3, integral coefficient k
i=15, described current controller adopts current comparator.
Described support capacitance module, for stable DC side voltage, provides harmonic wave and quadergy;
Described voltage detection module, for gathering DC side Support Capacitor voltage, as the input signal of controller module;
Described current detection module, for gathering the power network current at PCC module place, as the input signal of controller module;
Described controller module, for realizing the double-closed-loop control of voltage and current, Output rusults is as the input signal of pwm pulse generation module;
Described pwm pulse generation module, produce PWM waveform for the signal according to input, and after being driven by PWM waveform, output to the controlled tr tube of inverter module, be used for the on off operating mode of control switch pipe, control the output current of inversion module, make power network current trace command electric current;
Described inversion module, for being alternating current by DC inverter, to export needed for the available meritorious energy of photovoltaic cell and load humorous involves quadergy;
What photovoltaic flexibility grid-connection device was provided humorously involves reactive current i
chhumorous needed for size and load involves reactive current i
lhequal, direction is contrary, has i
ch=-i
lh;
So inversion module output current command value
with load current i
lsum is:
I
cfor inversion module actual output current, i
sfor electrical network actual current, consider the current error Δ i relevant with switching frequency, line voltage and DC voltage
s, Δ i
c, have:
So the relation of power network current, load current iL and inversion module output current, obtains
Then Δ i
s=Δ i
c;
The directly actuated scheme of power network current is adopted to make i
sfollow the tracks of
on controlling, APF Current Control with traditional is completely equivalent, realizes harmonics restraint and the reactive power compensation of power network current, provides equal with load by photovoltaic flexibility grid-connection device, direction is contrary humorously involves reactive current;
And then, obtain pwm pulse input signal through overcurrent controller;
Finally, described pwm pulse is carried out the state of each switching tube driven in rear control inversion unit, to make inversion unit output current, make power network current trace command electric current;
The control method of the flexible grid-connected system of this described photovoltaic, can relax the electrical network impact that load changing causes;
When load is directly incorporated into electrical network, needed for load, electric current is all provided by electrical network, i.e. i
s=i
l;
When supposing load changing, the fluctuation of load electric current produced is i '
l;
When being connected to the grid without the flexible grid-connected system device of photovoltaic, if the current fluctuation that electrical network produces is i
s'
2, can i be obtained
s+ i
s'
2=i
l+ i '
l;
Under load is connected to grid condition by PCC together with photovoltaic flexibility grid-connection device, if the current fluctuation of flexible photovoltaic grid-connecting apparatus and electrical network is respectively i '
cwith i '
s1, can i be obtained
s+ i '
s1=(i
l+ i '
l)+(i
c+ i '
c)=(i
l+ i
c)+(i '
l+ i '
c);
Because load current is contrary with inverter output current direction, known | i
l'+i
c' | <|i
l' |, obtain i '
s1<i '
s2, to suddenly change the fluctuation produced it can thus be appreciated that flexibility grid-connection device has shared a part of load current, relax load current fluctuations to the impact of electrical network, be conducive to the stable of electrical network, embody the electrical network complimentary nature that flexibility grid-connection device is brought;
Beneficial effect:
The invention provides a kind of photovoltaic flexibility grid-connection device and control method, contrive equipment is connected with electrical network by points of common connection together with load, realize while photovoltaic inversion generates electricity by way of merging two or more grid systems, suppressing and reactive power compensation mains by harmonics, and reduce the impact that load changing produces electrical network.This control method adopts double-loop control strategy, outer shroud gathers DC side Support Capacitor voltage, compared with given command voltage, inner ring instruction current is obtained through voltage controller, inner ring by instruction current with connect electrical network actual current compared with, produce pwm pulse through current controller again, control inversion unit and make power network current trace command electric current.The present invention only arranges place's current sensor with detection of grid electric current, directly controls power network current, and without the need to the current detection circuit of load and inversion unit, without the need to harmonics and reactive current detection and calculating, structure is simple, and easily realize, system dynamic is good.
Compared with prior art, the present invention has the following advantages:
The device of the flexible grid-connected system of photovoltaic provided by the invention and control method, directly gather PCC place power network current signal and DC capacitor voltage signal, DC voltage control is realized by the voltage controller in controller module, obtain electrical network instruction current, power network current command value is compared with power network current actual value, comparative result obtains the input of pwm pulse generation module through overcurrent controller, by PWM output waveform, through the break-make of each switching tube of drived control inverter, realize power network current and follow the tracks of the sinusoidal command value of power network current, current harmonics needed for load and idle component is provided by flexibility grid-connection device, reach the object to grid current harmonic suppression and reactive power compensation.When load is undergone mutation, the device of flexible grid-connected system can to suddenly change the current fluctuation brought by load sharing, reduces the impact of load current sudden change to electrical network, is conducive to the stability of electrical network.The present invention can relax the power network current impact that load changing causes, there is harmonics restraint and no-power compensation function, without the need to gathering harmonic source electric current and inverter output current, only needing to arrange place's current detecting, without the need to carrying out harmonics and reactive current detection, system configuration is simple; Control strategy is simple, easily realizes, and controls dynamic high, has electrical network complimentary nature.
Along with further investigation and the extensive use of photovoltaic power generation technology, realize photovoltaic generating system flexibility grid-connected, harmonics restraint no-power compensation function is completed in reversals, better can solve the power quality problem that the photovoltaic generation of power distribution network medium to high permeable rate and harmonic source bring, for improving the electrical network quality of power supply, alleviating electrical network burden and realizing electrical network complimentary nature, there is important and far-reaching meaning.
Accompanying drawing explanation
Fig. 1 is photovoltaic parallel in system structure chart of the prior art;
Fig. 2 is the structure chart of photovoltaic flexibility grid-connection device of the present invention;
Fig. 3 is the structural representation of the controller module of photovoltaic flexibility grid-connection device of the present invention;
Fig. 4 is the general structure schematic diagram of photovoltaic flexibility grid-connection device of the present invention;
Fig. 5 is the flow chart of the flexible grid-connected control method of photovoltaic.
Fig. 6 is A phase line voltage and power network current waveform, and figure a is the waveform dropping into electrical network without photovoltaic flexibility grid-connection device, and figure b is the waveform having photovoltaic flexibility grid-connection device to drop into electrical network;
Fig. 7 is grid current harmonic resultant distortion rate waveform; Figure a and figure b is the harmonic wave forms before and after photovoltaic flexibility grid-connection device drops into.
Embodiment
Below with reference to the drawings and specific embodiments, the present invention is described in further details:
Embodiment 1:
Fig. 2 is the structure drawing of device of the flexible grid-connected system of photovoltaic provided by the invention.
The photovoltaic flexibility grid-connection device that the present embodiment provides comprises: support capacitance module 201, voltage detection module 202, PCC module 203, current detection module 204, controller module 205, pwm pulse generation module 206 and inversion module 207;
Support capacitance module 201, for stable DC side voltage, provides required quadergy;
Voltage detection module 202, for gathering DC side Support Capacitor voltage, for the input signal as controller module;
PCC module 203, is made up of PCC switch and actuation means thereof, as the tie point of flexibility grid-connection device and load and electrical network;
Current detection module 204, for gathering the power network current at PCC module place, for the input signal as controller module;
Controller module 205, for realizing the double-closed-loop control of voltage and current, Output rusults is as the input signal of pwm pulse generation module;
Pwm pulse generation module 206, produce PWM waveform for the signal according to input, and output to each controlled tr tube of inverter module after being driven by PWM waveform, with the on off operating mode of control switch pipe, control the output current of inversion module, make power network current trace command electric current;
Inversion module 207, for being alternating current by DC inverter, to export needed for the available meritorious energy of photovoltaic cell and load humorous involves quadergy.
Fig. 3 is the structure chart of controller module 205.
Controller module comprises: voltage controller 205-1 and current controller 205-2.
Voltage controller 205-1, for realizing outer shroud voltage control, control command voltage and virtual voltage, export as inner ring command value;
Current controller 205-2, for realizing inner ring Current Control, control command electric current and actual electric network electric current, export the input value as pwm pulse generation module;
The device of the flexible grid-connected system of photovoltaic provided by the invention, working region voltage is selected according to maximal power tracing or system desired volume, selection instruction voltage, to ensure system worked well, directly gather DC capacitor voltage again, and then command voltage and DC voltage are controlled by voltage controller, Output rusults is as inner ring electrical network instruction current, directly gather PCC place power network current, instruction current and electrical network actual current are controlled by current controller, obtain the state of pwm pulse each switching tube in drived control inversion unit, and then control that inversion unit exports needed for the available active current of photovoltaic cell and load humorously involve idle component, thus make power network current follow the tracks of the sinusoidal instruction current of electrical network, realize flexible grid-connected.The present invention utilizes existing photovoltaic parallel in system just can realize, control inverter unit exports the electric current contrary with load harmonic and reactive current equal and opposite in direction, direction, to eliminate load harmonic and reactive current input electrical network, achieve the flexible harmonics restraint of grid-connected system of whole photovoltaic and the function of reactive power compensation, and eliminate load detecting circuit and inverter output current testing circuit, without the need to Harmonic currents detection technology, improve the reliability of control, reduce cost.Meanwhile, system also provides function for load, to reduce the impact of load changing to electrical network, has electrical network complimentary nature.
Fig. 4 is for inventing the example structure figure of the device provided herein.
Described Support Capacitor 201 is C
dc, be connected in parallel on DC side two ends, electric capacity C
dcthe direct voltage at two ends mates with photovoltaic cell direct voltage size, and electric capacity value is relevant to direct voltage size, and electric capacity value is larger, and DC voltage is more stable, but system dynamic reduces, and electric capacity value is little, and dynamic is better, but DC-side Voltage Stabilization reduces, ripple current increases, electric capacity C
dccan value be 100uF ~ 2200uF;
Described voltage detection module 202, is specially Hall element, for gathering the voltage at Support Capacitor two ends;
Described current detection module 204, is specially Hall element, for gathering PCC place power network current;
Current controller 205-2 in the present embodiment is specially current comparator;
Described pwm pulse generation module 206 is hysteresis comparator, and the ring width of hysteresis comparator is H, when
time, the output signal of hysteresis comparator remains unchanged, when
time, the output signal upset of hysteresis comparator, makes PMW pulse signal become low level from high level, output current i
sreduce; When
time, make pwm pulse signal become high level from low level, output current i
sincrease, in practical application, the generation of pwm pulse is not limited to use hysteresis comparator, and pwm pulse signal provides six, Q1 ~ Q6 tri-tunnel input signal for inversion module;
Described inversion module 207, form three-phase circuit by six controllable devices, the pwm signal that upper and lower bridge is corresponding is contrary;
Described load 30, as harmonic source, the uncontrollable rectification circuit of the three-phase be constituted by a diode connects impedance filter L
owith inductance R
ocomposition, wherein L
o=2mH, R
o=30 Ω;
The device that the present embodiment provides also comprises filter inductance L, wherein L=3mH.
Based on the device of the flexible grid-connected system of above-mentioned a kind of photovoltaic, present invention also offers the control method of the flexible grid-connected system of a kind of photovoltaic, specific embodiment is as follows.
Fig. 5 is control method embodiment flow chart provided by the invention.
The control method of the flexible grid-connected system of photovoltaic provided by the invention, comprising:
501: gather Support Capacitor voltage, power network current;
502: by the capacitance voltage and instruction voltage compare gathered, through voltage controller, obtain instruction current
described voltage controller is made up of comparator and proportional and integral controller, virtual voltage and instruction voltage, through comparator, outputs to PI(Proportional-Integral, proportional integral) adjuster, the output of pi regulator is instruction current, wherein the ratio value coefficient k of PI
p=0.3, integral coefficient k
i=15;
503: by the power network current and instruction current ratio of collection comparatively, through overcurrent controller, obtain pwm pulse input signal, described current controller is current comparator, for obtaining actual electric network i
sand instruction electric current
between difference;
504: the state of described pwm pulse being carried out each switching tube in drived control inversion unit, to make described power network current trace command electric current, pwm pulse signal is produced by hysteresis comparator, when
time, the output signal of hysteresis comparator remains unchanged, when
time, make PMW pulse signal become low level from high level, output current i
sreduce; When
time, make pwm pulse signal become high level from low level, output current i
sincrease;
Inversion module in the present embodiment is the controlled full-bridge of three-phase, is made up of six controlled tr tubes, and two is a phase, and upper bridge switch signal is contrary.
System output waveform corresponding to described embodiment as shown in Figure 6, Figure 7.Fig. 6 (a) and (b) are respectively with or without A phase line voltage during photovoltaic flexibility grid-connection device input electrical network and current waveform figure; Power network current THD(Total Harmonic Distortion when Fig. 7 (a) and (b) drop into electrical network with or without photovoltaic flexibility grid-connection device respectively, total harmonic distortion factor) waveform;
Fig. 6 (a) is the waveform dropping into electrical network without photovoltaic flexibility grid-connection device, and now power network current distortion is serious;
The waveform of Fig. 6 (b) for there being photovoltaic flexibility grid-connection device to drop into electrical network, now power network current waveform is abnormal very little, and waveform is good, and power network current effective value reduces simultaneously, this is because photovoltaic flexibility grid-connection device is that load provides electric energy, thus the electric energy that minimizing electrical network provides for load;
Shown in Fig. 6, when 0.3s, load current sudden change increases.Fig. 6 (a) finds out, under not putting into grid condition without photovoltaic flexibility grid-connection device, power network current follows load current change, rise rapidly, Fig. 6 (b) finds out that, under having photovoltaic flexibility grid-connection device to drop into grid condition, when load current sudden change increases, power network current increases gradually, seamlessly transit, the impact that electrical network is subject to reduces greatly;
Shown in Fig. 7 (a), drop into before photovoltaic flexibility grid-connection device, power network current THD, up to 26.94%, is mainly the times harmonics such as 5,7,11,13; Shown in Fig. 7 (b), drop into after photovoltaic flexibility grid-connection device, power network current THD only has 2.68%, and the effective value of the main times harmonics such as corresponding 5,7,11,13 greatly reduces, and THD is reduced;
The method of the flexible grid-connected system of photovoltaic provided by the invention, [this voltage generally adopts the some values between 800-1000v to select to be applicable to the voltage of working region according to maximal power tracing or system desired volume.], as command voltage, to ensure system worked well, directly gather DC capacitor voltage again, and then command voltage and DC voltage are controlled by voltage controller, Output rusults is as inner ring electrical network instruction current, directly gather PCC place power network current, instruction current and electrical network actual current are controlled by current controller, obtain the state of pwm pulse each switching tube in drived control inversion unit, and then control that inversion unit exports needed for the available active current of photovoltaic cell and load humorously involve idle component, thus make power network current follow the tracks of the sinusoidal instruction current of electrical network, realize flexible grid-connected.The present invention utilizes existing photovoltaic parallel in system just can realize, control inverter unit exports the electric current contrary with load harmonic and reactive current equal and opposite in direction, direction, to eliminate load harmonic and reactive current input electrical network, achieve the flexible harmonics restraint of grid-connected system of whole photovoltaic and the function of reactive power compensation, and eliminate load detecting circuit and inverter output current testing circuit, without the need to Harmonic currents detection technology, improve the reliability of control, reduce cost.Meanwhile, system also provides function for load, to reduce the impact of load changing to electrical network, has electrical network complimentary nature.
The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention.Although the present invention preferred embodiment discloses as above, but not to limit the present invention.All those of ordinary skill in the art, do not departing under technical solution of the present invention ambit, the Method and Technology content of above-mentioned announcement can be utilized to make many possible variations and modification to technical solution of the present invention, or change the Equivalent embodiments of equivalent variations into.Therefore, every content not departing from technical solution of the present invention, according to technical spirit of the present invention to any simple modification made for any of the above embodiments, equivalent variations and modification, all still belongs in the scope of the technology of the present invention protection.
Claims (5)
1. a photovoltaic flexibility grid-connection device, is characterized in that, comprising: support capacitance module, voltage detection module, PCC module, current detection module, controller module, pwm pulse generation module and inversion module;
The DC side parallel of support capacitance module and inversion module; The output side joint PCC module of inversion module; Described inversion module is three-phase bridge type converter;
The voltage signal at the support capacitance module two ends gathered by voltage detection module and the power network current signal of PCC module that gathered by current detection module are as the input signal of controller module, the output signal of controller module is as the input signal of pwm pulse generation module, the pulse signal that pwm pulse generation module produces is input to inversion module, controls the output of inversion module;
Photovoltaic flexibility grid-connection device is connected with electrical network and load respectively by described PCC module; Described controller module comprises voltage controller and current controller;
Described voltage controller, voltage based on voltage instruction value and Support Capacitor produces electrical network instruction current, output variable is as the input of current controller, and described voltage instruction value is according to tracing maximum power of photovoltaic cell control or the magnitude of voltage selected by electrical network desired volume;
Described current controller, control based on electrical network instruction current and electrical network actual current, make electrical network actual current follow the tracks of electrical network instruction current, control power network current signal only containing the active component of current, the Output rusults of current controller is as the input of described pwm pulse generation module;
Adopt the double circle controling mode based on voltage and current, that is:
Gather the voltage of Support Capacitor and the electrical network actual current at PCC module place;
Outer shroud is voltage control loop, and the difference that the command voltage of outer loop sets and the voltage compare of Support Capacitor obtain is input to voltage controller, and voltage controller output valve is electrical network instruction current;
Inner ring is current regulator, and the difference that electrical network instruction current and electrical network actual current compare gained is input to current controller, and current controller Output rusults, as the input of described pwm pulse generation module, makes electrical network actual current i
sfollow the tracks of electrical network instruction current
control power network current only containing the active component of current, i.e. electrical network instruction current
equal load current fundamental active component i
lfactive current i available with photovoltaic cell
cfsum, namely
2. photovoltaic flexibility grid-connection device according to claim 1, is characterized in that, described current detection module is current Hall transducer.
3. photovoltaic flexibility grid-connection device according to claim 1, is characterized in that, described voltage detection module is voltage hall sensor.
4., based on the flexible grid-connected control method of photovoltaic of photovoltaic flexibility grid-connection device according to claim 1, it is characterized in that, adopt the double circle controling mode based on voltage and current, that is:
Gather the voltage of Support Capacitor and the electrical network actual current at PCC module place;
Outer shroud is voltage control loop, the command voltage of outer loop sets and virtual voltage is compared the difference obtained and is input to voltage controller, and voltage controller output valve is electrical network instruction current;
Inner ring is current regulator, and electrical network instruction current and actual electric network current ratio are input to current controller compared with the difference of gained, and current controller Output rusults, as the input of described pwm pulse generation module, makes electrical network actual current i
sfollow the tracks of electrical network instruction current
control electrical network actual current only containing the active component of current, i.e. electrical network instruction current
equal load current fundamental active component i
lfactive current i available with photovoltaic cell
cfsum, namely
5. the flexible grid-connected control method of photovoltaic according to claim 4, it is characterized in that, voltage controller is pi regulator, the pi regulator ratio value coefficient k of this device
p=0.3, integral coefficient k
i=15, described current controller adopts current comparator.
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| CN112421632B (en) * | 2020-11-09 | 2023-05-26 | 广东电网有限责任公司江门供电局 | Nonlinear load power grid harmonic compensation control method |
| CN113328639B (en) * | 2021-07-09 | 2021-11-19 | 四川大学 | High-power electrolytic hydrogen production rectification power supply and control method |
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| CN100588071C (en) * | 2007-03-09 | 2010-02-03 | 中国科学院电工研究所 | Integrated control method for the combined network power generation and grid power active filtering |
| CN101330219A (en) * | 2008-06-06 | 2008-12-24 | 江苏林洋电子有限公司 | Multifunctional photovoltaic parallel inverting device |
| CN102377362B (en) * | 2011-09-30 | 2014-02-12 | 中国电力科学研究院 | Control method for voltage-source-type unit power factor high-temperature superconducting energy storage converter |
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