CN108767901B - Three-phase grid-connected inverter anti-reflux device and control method - Google Patents
Three-phase grid-connected inverter anti-reflux device and control method Download PDFInfo
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- 230000000151 anti-reflux effect Effects 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 16
- 239000003990 capacitor Substances 0.000 claims abstract description 41
- 230000002441 reversible effect Effects 0.000 claims description 16
- 238000001514 detection method Methods 0.000 claims description 13
- 230000002265 prevention Effects 0.000 claims description 13
- 230000007935 neutral effect Effects 0.000 claims description 9
- 238000010992 reflux Methods 0.000 claims description 4
- 230000002269 spontaneous effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000002427 irreversible effect Effects 0.000 description 1
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- H02J3/385—
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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
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
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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
- H02M1/12—Arrangements for reducing harmonics from ac input or output
- H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
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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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/539—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
- H02M7/5395—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
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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
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a three-phase grid-connected inverter anti-reflux device, wherein a main power circuit comprises a photovoltaic component, a BOOST circuit, a three-level inverter circuit, an inverter filter circuit and a grid-connected relay, wherein the BOOST circuit comprises an input filter capacitor, a BOOST inductor, a BOOST power tube, a BOOST diode and a bus capacitor; the three-level inverter circuit comprises a power tube and a diode; the inverter filter circuit includes an inductor and a capacitor. The invention also discloses a control method using the device, and by the anti-reflux control method, the output power of the inverter is matched with the local load power of each phase, so that the utilization rate of the photovoltaic module is improved, the cost of the anti-reflux controller is saved, the anti-reflux control precision is improved, and spontaneous self-use is really realized.
Description
Technical Field
The invention relates to a three-phase grid-connected inverter, in particular to a backflow prevention device and a control method for the three-phase grid-connected inverter.
Background
The current common method for preventing the inverter from flowing reversely is to detect the power of a power grid access point of a power grid through a reverse flow prevention controller, when the total power provided by the power grid to a load is detected to be less than a certain preset power, the output power of the inverter tends to be merged into the power grid, the inverter needs to be controlled in advance to reduce the power of the inverter, and the communication mode is completed through an RS-485 bus, a CAN bus or an Ethernet and the like. When the anti-backflow controller detects that backflow occurs, a power reduction command is sent through the bus or the inverter is directly disconnected from the power grid through the anti-backflow controller. Due to the delay of detection, control and communication of the control power reduction, the instability and fluctuation of the superposed load can be caused, and particularly in the critical area of the output power and the control power of the inverter, the output power of the inverter can oscillate.
For three-phase loads, when the backflow prevention controller detects that any phase has a backflow trend, the inverter is controlled to stop or reduce power, so that the output power of the inverter is not more than 3 times of the output power of the lowest phase, the output power of the inverter cannot be matched with all loads on a three-phase line, and the photovoltaic energy is wasted. If 3 single-phase inverters are independently controlled, the system cost is increased. Therefore, it is desirable to provide a control apparatus and a control method for a three-phase photovoltaic inverter with backflow prevention, which can integrate a backflow prevention function into an inverter for a single-use three-phase inverter, independently control output power of each phase, and realize independent backflow prevention control for each phase, for example, in a reversible system, the backflow prevention function can be turned off, and in an irreversible system, the backflow prevention function can be turned on.
Disclosure of Invention
The invention aims to solve the problems and provides a reverse-flow prevention device and a control method for a three-phase grid-connected inverter.
In order to achieve the purpose, the invention adopts the following technical scheme:
a three-phase grid-connected inverter anti-reflux device comprises a main power circuit, a grid-connected relay and a grid-connected inverter, wherein the main power circuit comprises photovoltaic modules PV 1-PVn, a BOOST circuit, a three-level inverter circuit, an inverter filter circuit and a grid-connected relay, wherein the BOOST circuit comprises an input filter capacitor C1, a BOOST inductor L1, a BOOST power tube Q1, a BOOST diode D1, a bus capacitor C2 and a bus capacitor C3; the three-level inverter circuit comprises power tubes Q2-Q13 and diodes D2-D7; the inverter filter circuit comprises inductors L2-L4 and capacitors C4-C6; the photovoltaic modules PV 1-PVn are connected in parallel with the input filter capacitor C1, the anodes of the photovoltaic modules PV 1-PVn are connected with one end of a Boost inductor L1, the other end of the Boost inductor L1 is connected with the anode of a Boost diode D1 and the drain of a Boost power tube Q1 in a star shape, one end of a bus capacitor C2 and the bus capacitor C3 are connected in series is connected with the cathode of a Boost diode D1, and the other end of the bus capacitor C2 and the source of the Boost power tube Q1 are connected; drains of power tubes Q2-Q4 are respectively connected with a cathode of a Boost diode D1, sources of power tubes Q11-Q13 are respectively connected with a source of a Boost power tube Q1, sources of power tubes Q2-Q4, cathodes of diodes D2-D4 and drains of power tubes Q5-Q7 are respectively connected in a star shape, diodes D2-D4 are respectively connected with anodes of diodes D5-D7, anodes of diodes D5-D7, sources of power tubes Q8-Q10 and drains of power tubes Q11-Q13 are respectively connected in a star shape, and sources of power tubes Q5-Q7 are respectively connected with drains of power tubes Q8-Q10; the source electrodes of the power tube Q5, the power tube Q6 and the power tube Q7 are respectively connected with one ends of inductors L2-L4, the other ends of the inductors L2-L4, one ends of capacitors C4-C6 and one end of a three-phase switch contact of a grid-connected relay K1 are respectively connected in a star shape, a connection point of bus capacitors C2 and C3, the cathodes of diodes D5-D7 and the other ends of the capacitors C4-C6 are connected with one end of a neutral line switch contact of the grid-connected relay K1, and the other ends of the three-phase switch contact and the neutral line switch contact of the grid-connected relay K1 are respectively connected with an A phase, a B phase, a C phase and a neutral line of a mains power grid.
A control method of a three-phase grid-connected inverter countercurrent prevention device comprises the following steps of:
(1) the PV voltage and current detection unit firstly samples the output voltage U of the photovoltaic polar platepvAnd an output current Ipv；
(2) The sampled electric quantity signal U is processedpvAnd IpvPerforming maximum power tracking through the MPPT unit;
(3) the MPPT unit calculates the output current average value reference I when the current maximum power point is calculatedorefAnd outputs PWM to control BOOST to output maximum power;
(4) the output current controller controls the output of the unit according to the three-phase anti-refluxaref、Ibref、IcrefAnd I of MPPT unit outputorefCalculating three-phase reference current according to the smaller value, and comparing the three-phase reference current with the inverted output current Ioa、Iob、IocAfter comparison, PI closed-loop control is carried out to respectively output Ua、Ub、UcFor the SPWM unit, the output of the SPWM unit controls a switching tube of the three-phase inverter main circuit to work;
(5) the inverter current detection unit is used for detecting the output current I of the three-phase inverter main circuitoa、Iob、IocAnd feeding back the detected signal to the output current controller to realize closed-loop control of each phase current and simultaneously detect the inverter current Ioa、Iob、IocSeparately connected A, B, C phase anti-reflux controlA control unit for calculating a given current of the phase;
(6) the power grid voltage detection unit is used for detecting the power grid voltage Uga、Ugb、UgcThe power grid incoming line current detection unit is used for detecting power grid incoming line current Iga、Igb、IgcAnd respectively feeding back the detected three-phase electric quantity signals to the A, B, C power grid power calculation unit, wherein the power grid power calculation is used for calculating the power P of each phase of the power grid inlet wirea、Pb、Pc；
(7) Determining whether the inverter has reverse current or not phase by phase, and controlling the reverse current by phase A according to PaAnd IoaCalculate IarefAnd output to the current control unit, formula Iaref＝Ioa-(Pa/Uga) When P isa<At 0, obtain Iaref<IoaObtaining that the inverter A phase is in the reverse flow state, otherwise, the inverter A phase is normal; b-phase anti-reflux control unit according to PbAnd IobCalculation of IbrefAnd output to the current control unit, formula Ibref＝Iob-(Pb/Ugb) When P isb<At 0, obtain Ibref<IobObtaining that the inverter B phase is in the reverse flow state, otherwise, the inverter B phase is normal; c-phase anti-reflux control unit according to PcAnd IocCalculation of IcrefAnd output to the current control unit, formula Icref＝Ioc-(Pc/Ugc) When P isc<At 0, obtain Icref<IocAnd the inverter C phase is in countercurrent, otherwise, the inverter C phase is normal.
The control method of the three-phase grid-connected inverter backflow prevention device is characterized in that the photovoltaic inverter backflow phenomenon passes through A, B, C-phase grid power P of a grid power calculation unita、Pb、PcThe working sequence is as follows:
(1) calculating formula P according to power of A, B, C-phase inverter grida＝Uga×Iga，Pb＝Ugb×Igb，Pc＝Ugc×IgcObtaining the power P of each phase of the invertera、Pb、Pc；
(2) When P is presenta、Pb、PcAnd when the value of the phase is less than zero, the phase in the photovoltaic inverter system is in the reverse flow state, otherwise, the phase in the photovoltaic inverter system is normal.
Compared with the prior art, the three-phase grid-connected inverter anti-reflux device and the control method thereof provided by the invention can realize the independent anti-reflux function of each phase of the three-phase inverter, the output power of the inverter is matched with the load power of each phase through anti-reflux control aiming at unbalanced local loads, the utilization rate of a photovoltaic assembly is improved, the inverter is used for detecting the incoming line power of the grid side and carrying out the anti-reflux control, the cost of an anti-reflux controller is saved, the anti-reflux control precision is improved, and the spontaneous self-use is really realized.
The device provided by the invention has the advantages of simple and practical structure, convenience in installation, installation and connection without modification of the existing local load distribution line, and investment saving.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a main power circuit diagram of the system of the present invention;
FIG. 2 is a block diagram of the system of the present invention.
The photovoltaic module comprises PV 1-PVn, a C1 input filter capacitor, an L1 boost inductor, a D1 boost diode, a Q1 boost power tube, a C2-C3. bus capacitor, a Q2-Q13 three-level inverter power tube, a D2-D7. three-level inverter diode, an L2-L4 inverter filter inductor, a C4-C6. inverter filter capacitor and an K1. grid-connected relay.
Detailed Description
The invention is further illustrated by the following figures and examples.
As shown in fig. 1, in the anti-reflux device for the three-phase grid-connected inverter in the embodiment, the main power circuit includes photovoltaic modules PV 1-PVn, a BOOST circuit, a three-level inverter circuit, an inverter filter circuit, and a grid-connected relay, wherein the BOOST circuit includes an input filter capacitor C1, a BOOST inductor L1, a BOOST power tube Q1, a BOOST diode D1, and bus capacitors C2 and C3; the three-level inverter circuit comprises power tubes Q2-Q13 and diodes D2-D7; the inverter filter circuit comprises inductors L2-L4 and capacitors C4-C6; the photovoltaic modules PV 1-PVn are connected in parallel with the input filter capacitor C1, the anodes of the photovoltaic modules PV 1-PVn are connected with one end of a Boost inductor L1, the other end of the Boost inductor L1 is connected with the anode of a Boost diode D1 and the drain of a Boost power tube Q1 in a star shape, one end of a bus capacitor C2 and the bus capacitor C3 are connected in series is connected with the cathode of a Boost diode D1, and the other end of the bus capacitor C2 and the source of the Boost power tube Q1 are connected; drains of power tubes Q2-Q4 are respectively connected with a cathode of a Boost diode D1, sources of power tubes Q11-Q13 are respectively connected with a source of a Boost power tube Q1, sources of power tubes Q2-Q4, cathodes of diodes D2-D4 and drains of power tubes Q5-Q7 are respectively connected in a star shape, diodes D2-D4 are respectively connected with anodes of diodes D5-D7, anodes of diodes D5-D7, sources of power tubes Q8-Q10 and drains of power tubes Q11-Q13 are respectively connected in a star shape, and sources of power tubes Q5-Q7 are respectively connected with drains of power tubes Q8-Q10; the source electrodes of the power tube Q5, the power tube Q6 and the power tube Q7 are respectively connected with one ends of inductors L2-L4, the other ends of the inductors L2-L4, one ends of capacitors C4-C6 and one end of a three-phase switch contact of a grid-connected relay K1 are respectively connected in a star shape, a connection point of bus capacitors C2 and C3, the cathodes of diodes D5-D7 and the other ends of the capacitors C4-C6 are connected with one end of a neutral line switch contact of the grid-connected relay K1, and the other ends of the three-phase switch contact and the neutral line switch contact of the grid-connected relay K1 are respectively connected with an A phase, a B phase, a C phase and a neutral line of a mains power grid.
With reference to fig. 1 and 2, an embodiment of a control method of a three-phase grid-connected inverter backflow prevention device is provided, and specifically, the units operate in the following order:
(1) the PV voltage and current detection unit firstly samples the output voltage U of the photovoltaic polar platepvAnd an output current Ipv；
(2) The sampled electric quantity signal U is processedpvAnd IpvPerforming maximum power tracking through the MPPT unit;
(3) the MPPT unit calculates the output current average value reference I when the current maximum power point is calculatedorefAnd outputs PWM to control BOOST to output maximum power;
(4) the output current controller controls the output of the unit according to the three-phase anti-refluxaref、Ibref、IcrefAnd I of MPPT unit outputorefCalculating three-phase reference current respectively according to smaller value, and outputting current I by inversionoa、Iob、IocAfter comparison, PI closed-loop control is carried out to respectively output Ua、Ub、UcFor the SPWM unit, the output of the SPWM unit controls a switching tube of the three-phase inverter main circuit to work;
(5) the inverter current detection unit is used for detecting the output current I of the three-phase inverter main circuitoa、Iob、IocAnd feeding back the detected signal to the output current controller to realize closed-loop control of each phase current and simultaneously detect the inverter current Ioa、Iob、IocRespectively connecting A, B, C phase anti-reflux control units for calculating the given current of the phase;
(6) the power grid voltage detection unit is used for detecting the power grid voltage Uga、Ugb、UgcThe power grid incoming line current detection unit is used for detecting power grid incoming line current Iga、Igb、IgcAnd respectively feeding back the detected three-phase electric quantity signals to the A, B, C power grid power calculation unit, wherein the power grid power calculation is used for calculating the power P of each phase of the power grid inlet wirea、Pb、Pc；
(7) Determining whether the inverter has reverse current or not phase by phase, and controlling the reverse current by phase A according to PaAnd IoaCalculate IarefAnd output to the current control unit, formula Iaref＝Ioa-(Pa/Uga) When P isa<At 0, obtain Iaref<IoaObtaining that the inverter A phase is in the reverse flow state, otherwise, the inverter A phase is normal; b-phase anti-reflux control unit according to PbAnd IobCalculation of IbrefAnd output to the current control unit, formula Ibref＝Iob-(Pb/Ugb) When P isb<At 0, obtain Ibref<IobObtaining that the inverter B phase is in the reverse flow state, otherwise, the inverter B phase is normal; c-phase anti-reflux control unit according to PcAnd IocCalculation of IcrefAnd output to the current control unit, formula Icref＝Ioc-(Pc/Ugc) When P isc<At 0, obtain Icref<IocAnd the inverter C phase is in countercurrent, otherwise, the inverter C phase is normal.
With reference to fig. 1 and 2, another embodiment of a control method of an anti-reflux device of a three-phase grid-connected inverter is provided, wherein the photovoltaic inverter reflux phenomenon passes through A, B, C-phase grid power P of a grid power calculation unita、Pb、PcThe working sequence is as follows:
(1) calculating formula P according to power of A, B, C-phase inverter grida＝Uga×Iga，Pb＝Ugb×Igb，Pc＝Ugc×IgcObtaining the power P of each item of the invertera、Pb、Pc；
(2) When P is presenta、Pb、PcAnd when the value of the phase is less than zero, the phase in the photovoltaic inverter system is in the reverse flow state, otherwise, the phase in the photovoltaic inverter system is normal.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (3)
1. A control method of a three-phase grid-connected inverter anti-reflux device is characterized by comprising the following steps: the work was performed in the following order:
(1) the PV voltage and current detection unit firstly samples the output voltage U of the photovoltaic polar platepvAnd an output current Ipv；
(2) The sampled electric quantity signal U is processedpvAnd IpvCarrying out maximum power tracking through an MPPT unit;
(3) the MPPT unit calculates the output current average value reference when the current maximum power point is calculatedIorefAnd outputs PWM to control BOOST to output maximum power;
(4) the output current controller controls the output of the unit according to the three-phase anti-refluxaref、Ibref、IcrefAnd I of MPPT unit outputorefCalculating three-phase reference current respectively according to smaller value, and outputting current I by inversionoa、Iob、IocAfter comparison, PI closed-loop control is carried out to respectively output Ua、Ub、UcFor the SPWM unit, the output of the SPWM unit controls the switching tube of the three-phase inverter main circuit to work;
(5) the inverter current detection unit is used for detecting the output current I of the three-phase inverter main circuitoa、Iob、IocAnd feeding back the detected signal to the output current controller to realize closed-loop control of each phase current and simultaneously detect the inverter current Ioa、Iob、IocRespectively connecting A, B, C phase anti-reflux control units for calculating the given current of the phase;
(6) the grid voltage detection unit is used for detecting the grid voltage Uga、Ugb、UgcThe power grid incoming line current detection unit is used for detecting power grid incoming line current Iga、Igb、IgcAnd respectively feeding back the detected three-phase electric quantity signals to the A, B, C power grid power calculation unit, wherein the power grid power calculation is used for calculating the power grid inlet wirePer phase power P ofa、Pb、Pc；
(7) Determining whether the inverter has reverse current or not phase by phase, and controlling the reverse current by phase A according to PaAnd IoaCalculate IarefAnd output to the current control unit, formula Iaref = Ioa -（Pa / Uga) When P isa <At 0, obtain Iaref < IoaObtaining that the inverter A phase is in the reverse flow state, otherwise, the inverter A phase is normal; b-phase anti-reflux control unit according to PbAnd IobCalculation of IbrefAnd output to the current control unit, formula Ibref = Iob -（Pb / Ugb) When P isb <At 0, obtain Ibref < IobObtaining that the inverter B phase is in the reverse flow state, otherwise, the inverter B phase is normal; c-phase anti-reflux control unit according to PcAnd IocCalculation of IcrefAnd output to the current control unit, formula Icref = Ioc -（Pc / Ugc) When P isc <At 0, obtain Icref < IocAnd the inverter C phase is in countercurrent, otherwise, the inverter C phase is normal.
2. The method as claimed in claim 1, wherein the grid-connected inverter backflow phenomenon is determined by A, B, C-phase grid power P of a grid power calculation unita、Pb、PcThe working sequence is as follows:
(1) calculating formula P according to power of A, B, C-phase inverter grida=Uga×Iga，Pb=Ugb×Igb，Pc=Ugc×IgcObtaining the power P of each item of the invertera、Pb、Pc；
(2) When P is presenta、Pb、PcWhen the numerical value of the phase is less than zero, the phase is in counter flow in the grid-connected inverter system, and otherwise, the phase is in counter flowThe phase is normal in the grid inverter system.
3. A three-phase grid-connected inverter backflow prevention device adopting the control method according to claim 1 or 2, characterized in that: the main power circuit comprises photovoltaic modules PV 1-PVn, a BOOST circuit, a three-phase inverter main circuit, an inverter filter circuit and a grid-connected relay, wherein the BOOST circuit comprises an input filter capacitor C1, a BOOST inductor L1, a BOOST power tube Q1, a BOOST diode D1, a bus capacitor C2 and a bus capacitor C3; the three-phase inverter main circuit comprises power tubes Q2-Q13 and diodes D2-D7; the inverter filter circuit comprises inductors L2-L4 and capacitors C4-C6; the photovoltaic module PV 1-PVn is connected with an input filter capacitor C1 in parallel, the positive electrodes of the photovoltaic modules PV 1-PVn are connected with one end of a Boost inductor L1, the other end of the Boost inductor L1 is connected with the positive electrode of a Boost diode D1 and the drain electrode of a Boost power tube Q1 in a star shape, one end of a bus capacitor C2 and the bus capacitor C3 are connected with the negative electrode of a Boost diode D1 after being connected in series, and the other end of the bus capacitor C2 and the bus capacitor C3 are connected with the source electrode of the Boost power tube Q1; drains of the power tubes Q2, Q3 and Q4 are respectively connected with a cathode of the Boost diode D1, sources of the power tubes Q11, Q12 and Q13 are respectively connected with a source of the Boost power tube Q1, a source of the power tube Q2, a cathode of the diode D2 and a drain of the power tube Q5 are connected in a star shape, a source of the power tube Q3, a cathode of the diode D3 and a drain of the power tube Q6 are connected in a star shape, and a source of the power tube Q4, a cathode of the diode D4 and a drain of the power tube Q7 are connected in a star shape;
the anode of the diode D2 is connected with the cathode of the diode D5, the anode of the diode D3 is connected with the cathode of the diode D6, and the anodes of the diodes D4 are respectively connected with the cathodes of the diodes D7;
the anode of the diode D5, the source of the power tube Q8 and the drain of the power tube Q11 are connected in a star shape, the anode of the diode D6, the source of the power tube Q9 and the drain of the power tube Q12 are connected in a star shape, and the anode of the diode D7, the source of the power tube Q10 and the drain of the power tube Q13 are connected in a star shape;
the source electrode of the power tube Q5 is connected with the drain electrode of the power tube Q8; the source electrode of the power tube Q6 is connected with the drain electrode of the power tube Q9; the source electrode of the power tube Q7 is connected with the drain electrode of the power tube Q10;
the source of the power tube Q5 is connected with one end of an inductor L2, the source of the power tube Q6 is connected with one end of an inductor L3, and the source of the power tube Q7 is connected with one end of an inductor L4;
the other end of the inductor L2, one end of the capacitor C4 and one end of the three-phase switch contact of the grid-connected relay K1 are connected in a star shape, the other end of the inductor L3, one end of the capacitor C5 and one end of the three-phase switch contact of the grid-connected relay K1 are connected in a star shape, and the other end of the inductor L4, one end of the capacitor C6 and one end of the three-phase switch contact of the grid-connected relay K1 are connected in a star shape;
the other ends of the connection points of the bus capacitors C2 and C3, the cathodes of the diodes D5, D6 and D7 and the other ends of the capacitors C4, C5 and C6 are connected with one end of a neutral line switch contact of the grid-connected relay K1, and the other ends of the three-phase switch contact and the neutral line switch contact of the grid-connected relay K1 are respectively connected with the phase A, the phase B, the phase C and the neutral line of the commercial power grid.
Priority Applications (1)
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| CN111355397B (en) * | 2020-04-17 | 2021-05-14 | 南通大学 | Single-phase high-gain photovoltaic grid-connected inverter with continuous input current and control method |
| CN111725841B (en) * | 2020-07-03 | 2021-11-02 | 石家庄科林物联网科技有限公司 | Photovoltaic inverter-based power quality optimization method for distribution transformer area |
| CN112290593B (en) * | 2020-11-02 | 2022-03-15 | 浙江艾罗网络能源技术股份有限公司 | Grid-connected inverter anti-reflux control method for 180-degree phase angle split-phase power grid |
| CN117607601A (en) * | 2024-01-24 | 2024-02-27 | 苏州腾圣技术有限公司 | Testing device for anti-countercurrent test of grid-connected inverter |
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