CN108110796A - A kind of photovoltaic generating system of component polarity ground connection - Google Patents

A kind of photovoltaic generating system of component polarity ground connection Download PDF

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Publication number
CN108110796A
CN108110796A CN201810069646.3A CN201810069646A CN108110796A CN 108110796 A CN108110796 A CN 108110796A CN 201810069646 A CN201810069646 A CN 201810069646A CN 108110796 A CN108110796 A CN 108110796A
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China
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switching tube
capacitance
diode
modules
cathode
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胡炎申
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胡炎申
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Priority to CN201810069646.3A priority Critical patent/CN108110796A/en
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381Dispersed generators
    • H02J3/382Dispersed generators the generators exploiting renewable energy
    • H02J3/383Solar energy, e.g. photovoltaic energy
    • H02J3/385Maximum power point tracking control for photovoltaic sources
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/02Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/06Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
    • H02M3/07Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS 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
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/66Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
    • H02M7/68Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters
    • H02M7/72Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/79Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with 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
    • H02M7/797Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with 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
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/56Power conversion systems, e.g. maximum power point trackers

Abstract

The invention discloses a kind of photovoltaic generating system of component polarity ground connection, including at least one component, the DC/DC module identical with component count and at least one DC/AC modules;One end ground connection of component, another input terminal for terminating corresponding DC/DC modules;One output termination dc bus of DC/DC modules, another output head grounding;One input termination dc bus of DC/AC modules, another input end grounding;The ac output end ground connection of DC/AC modules.The present invention can eliminate common mode leakage current to ensure the personal safety of terminal user and operation maintenance personnel.

Description

A kind of photovoltaic generating system of component polarity ground connection
Technical field
The present invention relates to the photovoltaic generating systems that photovoltaic generating system more particularly to a kind of component polarity are grounded.
Background technology
Traditional photovoltaic generating system in order to reduce between system and ground common mode leakage current and with power grid electrical isolation, photovoltaic Inverter is usually using power frequency or high frequency transformer, but Industrial Frequency Transformer volume is big and heavy, and high-frequency isolation control is complicated, this The major defect of class system is that transfer efficiency is lower, thus transless non-isolation type inverter is that the mainstream of photovoltaic system is opened up It flutters.Photovoltaic module generally use aluminium frame, safety standard requirements aluminium frame must be grounded, but under rainy day or wet environment, group Parasitic capacitance is up to 50nF-1uF/kWp to part over the ground.In transless non-isolation type photovoltaic generating system, AC network, light Volt component is connected by full-bridge inverter DC electrical, so as to which parasitic capacitance, filtering device and electric network impedance form common mode over the ground Resonant tank, as shown in Figure 1.The dynamic change of common-mode voltage will encourage this resonant tank and generate common mode leakage in parasitic capacitance Electric current.The size of common mode leakage current is directly proportional to parasitic capacitance and its common-mode voltage variation rate, and parasitic capacitance common-mode voltage is Two inverter bridge leg midpoints are to the half of the sum of component cathode voltage.When common mode leakage current is excessive, inverter stops trigger protection Machine so as to reduce photovoltaic power generation quantity, and generates excessive harmonic wave so as to influence output current wave quality, while in inverter Portion forms circulation, causes additional circulation loss, in addition also generates electromagnetic interference, more seriously common mode leakage current will threaten terminal User and the personal safety of operation maintenance personnel.
In order to reduce common mode leakage current, photovoltaic generating system generally use half-bridge or bipolar SPWM(Sinusoidal wave pulse width tune System)Full-bridge topologies, but the higher DC bus-bar voltage of half-bridge inverter requirement, industry use less in practice, and it is double The major defect of polar modulation full-bridge inverter is that output is two level, and increase switching loss causes bigger current ripples and filter Ripple inductance, therefore reduce transfer efficiency.In order to solve the common mode current leakage of transless non-isolation type photovoltaic DC-to-AC converter, Transfer efficiency is improved simultaneously, proposes some novel topological structures in recent years, such as H5 inverters and HERIC inverters, respectively such as Fig. 2 (a) and Fig. 2 are (shown in (b).Similar to full-bridge inverter, the DC input voitages of these topological structures, can be with without higher Unipolarity is used to modulate and export as three level, so as to not only reduce common mode leakage current, but also transfer efficiency is improved, while reduces inside The volume and weight of passive device.
Component string formation in series, and string formation connection in series-parallel forming array, herein, component, string formation or array with " component " or " photovoltaic module " is representative.Transless non-isolation type photovoltaic DC-to-AC converter will not only solve the safety such as common mode leakage current Problem also needs that universality is continuously improved for various assemblies.There are two polarity for component tool:Anode and cathode, while component is divided into Two big mainstream technology of crystal silicon and film, the surface oxide layer conductance burn into of silicon substrate and CIGS thin-film component is damp in order to prevent Crystal silicon component PID under wet environment(Polarity induced power is decayed)Effect must be grounded component cathode, efficient backgate crystal silicon component phase As also by its plus earth.Component polarity ground connection can bring a variety of benefits, but the inversions such as half-bridge, full-bridge, H5 or HERIC The equal cisco unity malfunction of device, and usually separately add isolating transformer or newly-increased virtual ground PID restraining devices, but can all increase and be Unite cost and improvement effect it is limited.Exchange is exported N lines by Karschny inverters shown in Fig. 3 without newly added equipment(In Property line)It is connected with component cathode, forms cathode ground connection photovoltaic system, common mode leakage current can be eliminated and improve PID effects, but it is very Few practical application.It is primarily due to that internal One Buck-Boost converter body is less efficient, and the power frequency of output not easy to control The positive and negative half cycle amplitude of sine wave is full symmetric, causes the greater risk to power grid injection direct-current component, while using a large amount of Power device, thus transfer efficiency is low, cost is higher and control is complicated.
The content of the invention
The technical problem to be solved in the present invention is to provide a kind of photovoltaic generating systems of the good component polarity ground connection of security.
In order to solve the above-mentioned technical problem, the technical solution adopted by the present invention is a kind of photovoltaic hair of component polarity ground connection Electric system, including at least one component, the DC/DC module identical with component count and at least one DC/AC modules;The one of component End ground connection, another input terminal for terminating corresponding DC/DC modules;One output termination dc bus of DC/DC modules, another Output head grounding;One input termination dc bus of DC/AC modules, another input end grounding;One friendship of DC/AC modules Flow output head grounding.
The photovoltaic generating system of above-described component polarity ground connection, including described at least one component and three DC/AC modules and with three-phase voltage increasing transformer, described in three DC/AC modules composition three-phase photovoltaic inverter;Three-phase photovoltaic Three ac output ends of inverter connect corresponding three-phase voltage increasing transformer primary side winding respectively, three-phase voltage increasing transformer primary side around The neutral ground of group.
The photovoltaic generating system of above-described component polarity ground connection include component cathode ground connection photovoltaic generating system and The photovoltaic generating system of component plus earth;For the photovoltaic generating system of component cathode ground connection, the anode of component connects corresponding The anode of DC/DC module inputs;The anode of DC/DC module output terminals connects dc bus, the cathode ground connection of output terminal;DC/AC The anode of module input connects dc bus, cathode ground connection;For the photovoltaic generating system of component plus earth, the cathode of component Connect the cathode of corresponding DC/DC module inputs;The cathode of DC/DC module output terminals connects dc bus, and the anode of output terminal connects Ground;The cathode of DC/AC module inputs connects dc bus, the plus earth of input terminal.
The photovoltaic generating system of above-described component polarity ground connection, DC/DC modules are booster converter, straight including first Stream filter capacitor, boost inductance, boosted switch pipe, booster diode, the first dc-link capacitance and bypass diode, first DC filter capacitor is connected between the positive electrode and negative electrode of DC/DC module inputs, and the first dc-link capacitance is connected on DC/DC modules Between the positive electrode and negative electrode of output terminal;For the photovoltaic generating system of component cathode ground connection, the first termination DC/DC of boost inductance The anode of module input, the anode of the second termination booster diode, the cathode of booster diode connect DC/DC module output terminals Anode;The second end of the high potential termination boost inductance of boosted switch pipe, low potential terminate the cathode of DC/DC module inputs; The anode of bypass diode connects the first end of boosting energy storage inductor, and cathode connects the cathode of booster diode;It is connect for component anode The photovoltaic generating system on ground, the cathode of the first termination DC/DC module inputs of boost inductance, the second termination booster diode Cathode, the anode of booster diode connect the cathode of DC/DC module output terminals;The low potential termination boost inductance of boosted switch pipe Second end, high potential terminate the anode of DC/DC module inputs;The cathode of bypass diode connects the first end of boost inductance, sun Pole connects the anode of booster diode;DC input voitage is less than in the case of output voltage, when boosted switch pipe is opened, boost inductance Energy storage, output energy are provided by the first dc-link capacitance;When boosted switch pipe turns off, the energy being stored on boost inductance leads to It crosses booster diode and is released to output terminal, and charge to the first dc-link capacitance;DC input voitage is more than output voltage feelings Under condition, converter realizes bypass functionality by bypass diode.
The photovoltaic generating system of above-described component polarity ground connection, DC/AC modules include the second dc-link capacitance, the One switching tube, second switch pipe, the 3rd switching tube, the 4th switching tube, the 5th switching tube, the first striding capacitance, the 6th diode, 7th diode, the first ac filter inductance, the second ac filter inductance and the first ac filter capacitance, the height of second switch pipe Current potential terminates the hot end of the 4th switching tube and the cathode of the 6th diode, the 3rd switch of low potential termination of second switch pipe The hot end of pipe;The low potential of 3rd switching tube terminates the anode of the 7th diode and the cold end of the 5th switching tube, the The cathode of seven diodes connects the cold end of the 4th switching tube, and the high potential of the 5th switching tube terminates the anode of the 6th diode; First striding capacitance is connected between the hot end of second switch pipe and the cold end of the 3rd switching tube;First ac filter electricity The cold end of first the 4th switching tube of termination of sense, second the second ac filter inductance of termination of the first ac filter inductance Second end, the hot end of the first the 5th switching tube of termination of the second ac filter inductance;The first of first ac filter capacitance Terminate the second end of the first ac filter inductance, the direct-flow input end of the second termination DC/AC modules of the first ac filter capacitance And be grounded, the second dc-link capacitance is connected on the ungrounded end of DC/AC modules direct current input and the cold end of second switch pipe Between;For the photovoltaic generating system of component cathode ground connection, the 3rd switching tube includes body diode, the high potential of first switch pipe The anode of DC/AC modules direct current input is terminated, low potential terminates the hot end of second switch pipe, the low potential of second switch pipe Terminate the cathode of DC/AC modules direct current input and ground connection;For the photovoltaic generating system of component plus earth, second switch pipe bag Body diode, the cathode of the low potential termination DC/AC modules direct current input of first switch pipe are included, high potential terminates the 3rd switching tube Cold end, the anode of the high potential termination DC/AC modules direct currents input of the 3rd switching tube and ground connection.
The photovoltaic generating system of above-described component polarity ground connection, for the photovoltaic generating system of component cathode ground connection, During DC/AC modules exchange output sine wave positive half cycle, first switch pipe, the 3rd switching tube and the 4th switching tube are open-minded, and second opens Pipe and the shut-off of the 5th switching tube are closed, the second dc-link capacitance is by the body diode of first switch pipe and the 3rd switching tube to the One striding capacitance charges, while by first switch pipe and the 4th switching tube and by the first ac filter inductance and the first exchange Filter capacitor realizes ac converter output;When 4th switching tube turns off, the second dc-link capacitance continues through first switch pipe It charges with the body diode of the 3rd switching tube to the first striding capacitance, while the energy being stored on the first ac filter inductance leads to It crosses the 3rd switching tube and the 7th diode realizes afterflow;During DC/AC modules exchange output sine wave negative half period, first switch pipe, 3rd switching tube and the shut-off of the 4th switching tube, second switch pipe and the 5th switching tube are open-minded, the storage energy of the first striding capacitance Realize that exchange is inverse by second switch pipe and the 5th switching tube and by the second ac filter inductance and the first ac filter capacitance Become output;When 5th switching tube turns off, the energy being stored on the second ac filter inductance passes through second switch pipe and the six or two Pole pipe realizes afterflow;For the photovoltaic generating system of component plus earth, when the exchange of DC/AC modules exports sine wave negative half period, First switch pipe, second switch pipe and the 5th switching tube are open-minded, the 3rd switching tube, the shut-off of the 4th switching tube, the second dc bus Capacitance is charged by the body diode and first switch pipe of second switch pipe to the first striding capacitance, while passes through first switch Pipe, the 5th switching tube simultaneously realize ac converter output by the second ac filter inductance and the first ac filter capacitance;5th opens When closing pipe shut-off, the second dc-link capacitance continue through second switch pipe body diode and first switch pipe to first it is winged across Capacitance charges, while the energy being stored on the second ac filter inductance is realized by second switch pipe and the 6th diode and continued Stream;During DC/AC modules exchange output sine wave positive half cycle, second switch pipe, first switch pipe and the shut-off of the 5th switching tube, the 3rd Switching tube and the 4th switching tube are open-minded, and the energy of the first striding capacitance storage by the 3rd switching tube, the 4th switching tube and passes through First ac filter inductance and the first ac filter capacitance realize ac converter output;When 4th switching tube turns off, the is stored in The energy of one ac filter inductance passes through the 3rd switching tube, the 7th diode continuousing flow.
The photovoltaic generating system of above-described component polarity ground connection, DC/AC modules are converted including two-way Buck-Boost Device and half-bridge inversion circuit, two-way One Buck-Boost converter body include the 13rd switching tube, the 14th switching tube, the 17th pole Pipe, the 18th diode, the 12nd energy storage inductor and the 14th energy storage inductor, half-bridge inversion circuit include upper capacitance, lower capacitance, 11st switching tube, the 12nd switching tube, the 15th diode, the 16th diode, the 11st ac filter inductance, the 13rd Ac filter inductance and the second ac filter capacitance;The high potential of 13rd switching tube terminates the cathode of the 17th diode, low Current potential terminates the cathode of the 18th diode and the first end of the 12nd energy storage inductor;The high potential termination the of 14th switching tube The first end of the anode of 17 diodes and the 14th energy storage inductor, low potential terminate the anode of the 18th diode;12nd Ground terminal and first ac output end of the second end of energy storage inductor as DC/AC modules, connect the second of the 14th energy storage inductor End;The high potential of 11st switching tube terminates the cathode of the 15th diode, low potential terminate the 16th diode cathode and The first end of 11st ac filter inductance;The high potential of 12nd switching tube terminates the anode and the 13rd of the 15th diode The first end of ac filter inductance, low potential terminate the anode of the 16th diode;The second end of 11st ac filter inductance As the second ac output end of DC/AC modules, the second end of the 13rd ac filter inductance is connect;Second ac filter capacitance connects Between the first ac output end and the second ac output end of DC/AC modules;The anode of upper capacitance connects the 13rd switching tube The hot end of hot end and the 11st switching tube, the cathode of upper capacitance connect the ground terminal of DC/AC modules;The anode of lower capacitance The cathode of capacitance is connected, the cathode of lower capacitance connects the cold end of the 14th switching tube and the cold end of the 12nd switching tube.
The photovoltaic generating system of above-described component polarity ground connection, for the photovoltaic generating system of component cathode ground connection, Upper capacitance is the 3rd dc-link capacitance, and the just extremely direct-flow input end anode of DC/AC modules of upper capacitance, lower capacitance is the tenth Three DC filter capacitors;For the photovoltaic generating system of component plus earth, lower capacitance be the 3rd dc-link capacitance, lower capacitance Cathode be DC/AC modules direct-flow input end cathode, upper capacitance be the 13rd DC filter capacitor;When upper capacitance terminal voltage is big When lower capacitance terminal voltage, the 13rd switching tube is opened, the shut-off of the 14th switching tube, and upper capacitance is by the 13rd switching tube to the 12 energy storage inductors charge;When 13rd switching tube turns off, the energy for being stored in the 12nd energy storage inductor passes through the 18th pole Pipe charges to lower capacitance;When upper capacitance terminal voltage is less than lower capacitance terminal voltage, the 14th switching tube is opened, the 13rd switching tube Shut-off, lower capacitance are charged by the 14th switching tube to the 14th energy storage inductor;When 14th switching tube turns off, the tenth is stored in The energy of four energy storage inductors is powered on capacity charge by the 17th diode;By the continuous HF switch course of work, realize Upper capacitance, lower capacitance terminal voltage equipotential;Exchange output sine wave positive half cycle when, at this time the 11st switching tube open, the 12nd Switching tube turns off, and upper capacitance is by the 11st switching tube and real by the 11st ac filter inductance and the second ac filter capacitance Existing ac converter output;When 11st switching tube turns off, the energy being stored on the 11st ac filter inductance passes through lower capacitance Afterflow is realized with the 16th diode;During exchange output sine wave negative half period, the 11st switching tube turns off and the 12nd switching tube Open-minded, lower capacitance is handed over by the 12nd switching tube and by the 13rd ac filter inductance, the second ac filter capacitance to realize Flow inversion output;When 12nd switching tube turns off, the energy for being stored in the 13rd ac filter inductance passes through upper capacitance and the tenth Five diode continuousing flows.
The photovoltaic generating system of above-described component polarity ground connection, DC/AC modules include the 4th dc-link capacitance, the 21 switching tubes, the 22nd switching tube, the 23rd switching tube, the 24th switching tube, the 25th switching tube, second 13 striding capacitances, the 21st ac filter inductance and the 3rd ac filter capacitance, the 22nd switching tube, the 23rd are opened Guan Guan, the 24th switching tube and the 25th switching tube respectively include body diode;The high potential termination of 22nd switching tube The hot end of 24th switching tube, the low potential of the 22nd switching tube terminate the hot end of the 23rd switching tube; The low potential of 23rd switching tube terminates the cold end of the 25th switching tube, the low potential termination of the 24th switching tube The hot end of 25th switching tube and the first end of the 21st ac filter inductance;23rd striding capacitance is connected on Between the cold end of the hot end of 22 switching tubes and the 23rd switching tube;The first end of 3rd ac filter capacitance As the first ac output end of DC/AC modules, the second end of the 21st ac filter inductance, the 3rd ac filter capacitance are connect Second ac output end of the second end as DC/AC modules, connect the ground terminals of DC/AC module direct-flow input ends;4th direct current Bus capacitor is connected between the ungrounded end of DC/AC modules direct current input and the cold end of the 22nd switching tube;For group The photovoltaic generating system of part cathode ground connection, the 23rd switching tube include body diode, the hot end of the 21st switching tube The anode of DC/AC modules direct current input is connect, low potential terminates the hot end of the 22nd switching tube, the 22nd switching tube The cathode of low potential termination DC/AC modules direct current input and ground connection;For the photovoltaic generating system of component plus earth, the 20th Two switching tubes include body diode, the cathode of the low potential termination DC/AC modules direct current input of the 21st switching tube, high potential The cold end of the 23rd switching tube is terminated, the high potential termination DC/AC modules direct current input of the 23rd switching tube is just Pole is simultaneously grounded;For the photovoltaic generating system of component cathode ground connection, when the exchange of DC/AC modules exports sine wave positive half cycle, second 11 switching tubes, the 23rd switching tube and the 24th switching tube are open-minded, the 22nd switching tube and the 25th switching tube Shut-off, the 4th dc-link capacitance are flown by the body diode of the 21st switching tube and the 23rd switching tube to the 23rd Across capacitance charging, at the same by the 21st switching tube and the 24th switching tube and by the 21st ac filter inductance and 3rd ac filter capacitance realizes ac converter output;When 24th switching tube turns off, the 4th dc-link capacitance continues to lead to The body diode for crossing the 21st switching tube and the 23rd switching tube charges to the 23rd striding capacitance, while is stored in the Energy on 21 ac filter inductance is realized continuous by the body diode of the 23rd switching tube and the 25th switching tube Stream;During DC/AC modules exchange output sine wave negative half period, the 21st switching tube, the 23rd switching tube and 24-carat gold Pipe shut-off is closed, the 22nd switching tube and the 25th switching tube are open-minded, and the storage energy of the 23rd striding capacitance passes through the 22 switching tubes and the 25th switching tube are simultaneously realized by the 21st ac filter inductance and the 3rd ac filter capacitance Ac converter exports;When 25th switching tube turns off, the energy on the 21st ac filter inductance is stored in by second The body diode of 12 switching tubes and the 24th switching tube realizes afterflow;For the photovoltaic generating system of component plus earth, During DC/AC modules exchange output sine wave negative half period, the 21st switching tube, the 22nd switching tube and the 25th switching tube It is open-minded, the 23rd switching tube, the shut-off of the 24th switching tube, the body that the 4th dc-link capacitance passes through the 22nd switching tube Diode and the 21st switching tube charge to the 23rd striding capacitance, while pass through the 21st switching tube, the 25th Switching tube simultaneously realizes ac converter output by the 21st ac filter inductance and the 3rd ac filter capacitance;25th opens Close pipe shut-off when, the 4th dc-link capacitance continue through the 22nd switching tube body diode and the 21st switching tube to 23rd striding capacitance charges, while the energy being stored on the 21st ac filter inductance passes through the 24th switching tube Body diode and the 22nd switching tube afterflow;During DC/AC modules exchange output sine wave positive half cycle, the 22nd switch Pipe, the 21st switching tube and the shut-off of the 25th switching tube, the 23rd switching tube and the 24th switching tube are open-minded, and second The energy of 13 striding capacitances storage is by the 23rd switching tube, the 24th switching tube and passes through the 21st ac filter Inductance and the 3rd ac filter capacitance realize ac converter output;When 24th switching tube turns off, the 21st friendship is stored in Flow body diode and two ten three switching tube afterflow of the energy of filter inductance by the 23rd switching tube.
The photovoltaic generating system of above-described component polarity ground connection, DC/AC modules are converted including two-way Buck-Boost Device and half-bridge inversion circuit, two-way One Buck-Boost converter body include the 33rd switching tube, the 34th switching tube and the 3rd 12 energy storage inductors, half-bridge inversion circuit include upper capacitance, lower capacitance, the 31st switching tube, thirty-twomo and close pipe and the 31 ac filter inductance and the 4th ac filter capacitance, the 31st switching tube, thirty-twomo close pipe, 33 switches Pipe and the 34th switching tube respectively include body diode;The anode of the upper capacitance of the high potential termination of 33rd switching tube is low Current potential terminates the hot end of the 34th switching tube and the first end of the 32nd energy storage inductor;32nd energy storage inductor Ground terminal and first ac output end of the second end as DC/AC modules;The lower capacitance of low potential termination of 34th switching tube Cathode;The low potential termination thirty-twomo of 31st switching tube closes the hot end of pipe and the 31st ac filter electricity The first end of sense;Second ac output end of the second end of 31st ac filter inductance as DC/AC modules, the 4th exchange Filter capacitor is connected between the first ac output end of DC/AC modules and the first ac output end;The anode of upper capacitance connects the 3rd The hot end of the hot end of 13 switching tubes and the 31st switching tube, the cathode of upper capacitance connect the ground connection of DC/AC modules End;The anode of lower capacitance connects the cathode of capacitance, and the cathode of lower capacitance connects the cold end and the 30th of the 34th switching tube The cold end of two switching tubes;For the photovoltaic generating system of component cathode ground connection, upper capacitance is the 5th dc-link capacitance, on The just extremely direct-flow input end anode of DC/AC modules of capacitance, lower capacitance are the 33rd DC filter capacitor;For component just The photovoltaic generating system of pole ground connection, lower capacitance are the 5th dc-link capacitance, and the cathode of lower capacitance is defeated for the direct current of DC/AC modules Enter and hold cathode, upper capacitance is the 33rd DC filter capacitor;When upper capacitance terminal voltage is more than lower capacitance terminal voltage, the 30th Three switching tubes are opened, the shut-off of the 34th switching tube, and upper capacitance is filled by the 33rd switching tube to the 32nd energy storage inductor Electricity;When 33rd switching tube turns off, the energy for being stored in the 32nd energy storage inductor passes through two pole of body of 34 switching tubes Pipe charges to lower capacitance;When upper capacitance terminal voltage is less than lower capacitance terminal voltage, the 34th switching tube is opened, the 33rd opens Pipe shut-off is closed, lower capacitance is charged by the 34th switching tube to 32 energy storage inductors;When 34th switching tube turns off, deposit Store up energy by the body diodes of 33 switching tubes to being powered on capacity charge;By the continuous HF switch course of work, Capacitance, lower capacitance terminal voltage equipotential in realization;Exchange output sine wave positive half cycle when, at this time the 31st switching tube open, Thirty-twomo closes pipe shut-off, and upper capacitance is handed over by the 31st switching tube and by the 31st ac filter inductance and the 4th It flows filter capacitor and realizes ac converter output;When 31st switching tube turns off, it is stored on the 31st ac filter inductance Energy pass through thirty-twomo close pipe body diode and lower capacitance and realize afterflow;During exchange output sine wave negative half period, 31st switching tube turns off and thirty-twomo pass pipe is open-minded, and lower capacitance is closed by thirty-twomo manages and pass through the 31st Ac filter inductance and with the 4th ac filter capacitance and realize ac converter export;When thirty-twomo closes pipe shut-off, storage The body diode afterflow that energy on the 31st ac filter inductance passes through upper capacitance and the 31st switching tube.
The three-phase photovoltaic power generation system of component of embodiment of the present invention polarity ground connection can eliminate common mode leakage current to ensure end The personal safety of end subscriber and operation maintenance personnel.
Description of the drawings]
The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
Fig. 1 is the common mode electric leakage flow diagram of prior art full-bridge inverter.
Fig. 2 a are the circuit diagrams of prior art transless non-isolation type H5 photovoltaic DC-to-AC converters.
Fig. 2 b are the circuit diagrams of prior art transless non-isolation type HERIC photovoltaic DC-to-AC converters.
Fig. 3 is the circuit diagram of prior art Karschny inverters.
Fig. 4 is the schematic diagram of the three-phase photovoltaic power generation system of component of embodiment of the present invention polarity ground connection.
Fig. 5 is the schematic diagram of the single-phase photovoltaic power generation system of component of embodiment of the present invention polarity ground connection.
Fig. 6 is the circuit diagram of the DC/DC module embodiments 1 of negative ground system of the present invention.
Fig. 7 is the circuit diagram of the DC/AC module embodiments 1 of negative ground system of the present invention.
Fig. 8 is the circuit diagram of the DC/AC module embodiments 2 of negative ground system of the present invention.
Fig. 9 is the circuit diagram of the DC/AC module embodiments 3 of negative ground system of the present invention.
Figure 10 is the circuit diagram of the DC/AC module embodiments 4 of negative ground system of the present invention.
Figure 11 is the circuit diagram of the DC/DC module embodiments 1 of positive ground system of the present invention.
Figure 12 is the circuit diagram of the DC/AC module embodiments 1 of positive ground system of the present invention.
Figure 13 is the circuit diagram of the DC/AC module embodiments 2 of positive ground system of the present invention.
Figure 14 is the circuit diagram of the DC/AC module embodiments 3 of positive ground system of the present invention.
Figure 15 is the circuit diagram of the DC/AC module embodiments 4 of positive ground system of the present invention.
Figure 16 is the circuit diagram of the three-phase photovoltaic power generation system of cathode of embodiment of the present invention ground connection.
Figure 17 is the circuit diagram of the three-phase photovoltaic power generation system of plus earth of the embodiment of the present invention.
Specific embodiment]
The three-phase photovoltaic power generation system of component of embodiment of the present invention polarity ground connection is by high-performance three-phase photovoltaic inverter, component, liter Pressure transformer and three-phase AC grid are formed, and belong to transless non-isolation type technology, and critical component is matched high property Can three-phase photovoltaic inverter, three-phase photovoltaic inverter is by multiple DC/DC modules, three DC/AC module compositions, as shown in Figure 4.
DC/DC modules are suitable for wider DC input voitage scope, and n DC/DC module can realize photovoltaic system n road MPPT Tracking;DC/AC modules realize DC-AC inversion, and control ac output current to generate electricity by way of merging two or more grid systems or off-network application.Boosting Inverter ac output low pressure is promoted to 10kV or 35kV voltages etc. by transformer, is then incorporated into three-phase medium voltage network;Without using During step-up transformer, inverter ac output connection loads or is directly incorporated into three-phase low-voltage power grid, such as 380V.
In the following description, for the photovoltaic generating system of component cathode ground connection, A ends are the output terminals of DC/DC modules Cathode(Ground terminal), B ends are the output head anodes of DC/DC modules, and C-terminal is the input anode of DC/DC modules;A ends are DC/AC The input cathode of module, b ends are the direct-flow input end anodes of DC/AC modules, and c ends are the ac output ends of DC/AC modules.It is right In the photovoltaic generating system of component plus earth, A ends are the output head anodes of DC/DC modules(Ground terminal), B ends are DC/DC moulds The negative pole of output end of block, C-terminal are the input cathodes of DC/DC modules;A ends are the input anodes of DC/AC modules, and b ends are DC/ The direct-flow input end cathode of AC modules, c ends are the ac output ends of DC/AC modules.
As shown in figure 4, for the photovoltaic generating system of component cathode ground connection, the C-terminal of n DC/DC module connects respectively respectively From component anode;B ends are uniformly connected to the b ends that DC/AC modules are then connected to after dc bus, form the input of DC/AC modules;A End and connects all components cathode together with being connected to a ends of DC/AC modules, then with step-up transformer T1 or not connecing transformer When exchange output N lines be grounded together, be referred to as negative ground system.The c ends of three DC/AC modules are the three-phase of inverter Output connects threephase load or is directly incorporated into exchange when being connected to the three-phase input end of step-up transformer T1 or not connecing transformer Low voltage electric network.The C-terminal of DC/DC modules may also connect to respective component cathode;B ends reconnect after being still uniformly connected to dc bus To the b ends of DC/AC modules, the input of DC/AC modules is formed;And a ends of A ends and DC/AC modules are connected to together at this time, and All components anode is connected, then is grounded with step-up transformer T1 or when not connecing transformer together with the N lines of exchange output, referred to as just Pole earthed system.In addition, a DC/DC module can also be used in system, single channel MPPT functions can only be so realized.It may be noted that , this system is not only suitable for generating electricity by way of merging two or more grid systems, it can also be used in various off-network types and accumulation energy type inverter.
High-performance three-phase photovoltaic inverter can be also used instead in the single-phase photovoltaic power generation system of component polarity ground connection, only need handle Three DC/AC modules are kept to one, High-performance Single-Phase photovoltaic DC-to-AC converter as shown in Figure 5.By configuring DC/DC module numbers, It can flexibly realize photovoltaic system single channel or multichannel MPPT functions.Similar to Fig. 4, single-phase inverter also may make up anode or negative Pole earthed system, basic principle is similar to three-phase inverter, and explanation is not repeated herein.
Therefore, high-performance three-phase and single-phase photovoltaic inverter can form cathode ground connection system according to the polarity that component is grounded System or positive ground system, but two kinds of system internal DC/DC modules, topological structures of DC/AC modules are not fully identical, Fig. 6- The embodiment of Figure 10 is i.e. for negative ground system.
In the DC/DC module embodiments of negative ground system shown in Fig. 6, Boost converter, wherein C1 are employed For DC filter capacitor, L5 is Boost energy storage inductors, and S9 is power switch pipe, D9 is its body diode, and D10 is two pole of power Pipe, D11 are frequency bypass diode, and C2 is dc-link capacitance.This converter externally has A, B, C-terminal mouth, corresponds to respectively A, B, C-terminal mouth in Fig. 4, Fig. 5.DC input voitage is less than in the case of output voltage, when S9 is opened, L5 energy storage, exports energy It is provided by C2;When S9 is turned off, the energy being stored on L5 is discharged to output by D10 and charged to C2, power switch tube S 9 It is switched on or off instruction and comes from control circuit or MCU(Microcontroller).DC input voitage is more than in the case of output voltage, becomes Parallel operation realizes bypass functionality by D11.It is pointed out that the switching frequency of DC/DC converters is generally higher, therefore power MOSFET can be used in switching tube(MOS memory), IGBT may be used when switching frequency is relatively low(Insulated gate Bipolar transistor), and power diode is using fast recovery or SiC(Carborundum)Etc. types.The inner topology knot of DC/DC modules Above-mentioned Boost converter had both can be used in structure, it is possible to use also other various types can be used to isolate for Buck buck converters Type or non-isolation type DC/DC converters.
In the DC/AC module embodiments 1 of negative ground system shown in Fig. 7, striding capacitance and full bridge inverter are employed Without dead-zone technique, wherein C5 is dc-link capacitance, and S1, S2, S3, S4, S5 are power switch pipe, and D1, D2, D3, D4, D5 distinguish For its body diode, C3 is striding capacitance, and D6, D7 are power diode, and L1, L2 are ac filter inductance, and C4 is ac filter Capacitance.The present embodiment externally has a, b, c port, is electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.Exchange output sine wave During positive half cycle, S1, S3, S4 are opened at this time and S2, S5 are turned off, and C5 is charged by the body diode D3 of S1, S3 to C3, is led to simultaneously It crosses S1, S4 and is filtered by L1, C4 and realize that ac converter exports, inverter bridge leg midpoint d is to the voltage value at a ends and C5 ends at this time Voltage equipotential and with "+1 " refer to;When S4 is turned off, the body diode D3 that C5 continues through S1, S3 charges to C3, stores simultaneously Energy on L1 realizes afterflow by S3, D7, and d is zero to the voltage value at a ends and is referred to " 0 " at this time.Exchange output is sinusoidal During ripple negative half period, S1, S3, S4 are turned off and S2, S5 are open-minded, and the storage energy of C3 filters to realize by S2, S5 and by L2, C4 Ac converter exports, and inverter bridge leg midpoint e mutually refers to the voltage value at a ends with C3 terminal voltages with " -1 " instead at this time;S5 is turned off When, it is stored in the energy of L2 and afterflow is realized by S2, D6, e is zero to the voltage value at a ends and is referred to " 0 " at this time.S1, S3 are opened When logical, C3 is to be connected in parallel substantially with C5, thus can reduce DC bus current ripple.Meanwhile inverter bridge leg midpoint d and e "+1 ", " 0 ", " -1 " three kinds of level are generated to a ends, thus realize the three level output of inverter circuit.
From the foregoing, it can be seen that during exchange output sine wave positive half cycle, power switch tube S 1, S3 are only the work of power frequency low frequency switch And IGBT device can be used, S4 can be used MOSFET for high-frequency work during this period, can also be used when switching frequency is relatively low Fast recovery or SiC also can be used for high-frequency work during this period in IGBT, D7(Carborundum)Etc. types;Exchange output sine wave is born During half cycle, power switch tube S 2 is only the work of power frequency low frequency switch and IGBT device can be used, and S5 is high-frequency work during this period And MOSFET can be used, IGBT, D6 can also be used also to can be used during this period for high-frequency work fast extensive when switching frequency is relatively low Multiple or SiC(Carborundum)Etc. types.Simultaneously as the bi-directional conductive of power switch pipe and its body diode, it will be apparent that this DC/AC modules can realize the two-way flow of energy, so as to which system has active output and reactive power compensation planning.By S4 and D7 or In the same inverter bridge leg that S5 and D6 is respectively constituted, inside be only connected in series by power switch pipe and power diode, without It directly connects there are switching tube, also referred to as without dead-zone technique, this mode can eliminate Switch Cut-through risk, improve reliable operation Property.Five power switch pipes and two power diodes are the work of half power frequency period, two of which power switch pipe, two Power diode HF switch in half of power frequency period works, and in addition power tube is open-minded there are two loop of power circuit, so as to drop Low-power consumption improves transfer efficiency, while reduces power device thermal stress, further improves functional reliability.Power switch Pipe is switched on or off instruction and comes from control circuit or MCU(Microcontroller), modulated by using Unipolar SPWM and realize output "+1 ", " 0 ", " -1 " three kinds of level, so as to reduce internal passive the device such as size of inductance, capacitance and volume, alleviate Inverter weight, and further improve transfer efficiency.The a ends of DC/AC modules exchange output N lines and directly connect with component cathode It connects, completely eliminates common mode leakage current, improves security of system.Meanwhile the high-frequency tube of internal circuit uses MOSFET and power frequency pipe Using IGBT, DC/AC module costs are reduced to a certain extent.
In the DC/AC module embodiments 2 of negative ground system shown in Fig. 8, employ two-way One Buck-Boost converter body and For high-frequency switch circuit without dead-zone technique, wherein C5 is dc-link capacitance, and S1, S2, S3, S4 are power switch pipe, D1, D2, D3, D4 is respectively its body diode, and C3 is DC filter capacitor, and D5, D6, D7, D8 are power diode, and L1, L3 are ac filter electricity Sense, C4 are ac filter capacitance, and L2, L4 are Buck-Boost energy storage inductors.S3, S4, D7, D8, L2, L4 form two-way Buck- Boost, C5, C3, S1, S2, D5, D6, L1, L3, C4 form half-bridge inversion circuit.This embodiment externally have a, b, C ports are electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.When C5 terminal voltages are more than C3 terminal voltages, S3 is opened at this time and S4 is closed Disconnected, C5 is charged by S3 to L2;When S3 is turned off, the energy for being stored in L2 is charged by D8 to C3.Otherwise C5 terminal voltages are less than C3 During terminal voltage, S4 is opened at this time and S3 is turned off, and C3 is charged by S4 to L4;When S4 is turned off, be stored in the energy of L4 by D7 to C5 charges.So as to by the continuous HF switch course of work, finally realize C5, C3 terminal voltage equipotential, this is also that half-bridge is inverse Become the precondition that circuit effectively works, finally achievable half-bridge inversion circuit injection load or the smaller direct current of AC network Flow component.During exchange output sine wave positive half cycle, S1 is opened at this time and S2 is turned off, and C5 is filtered by S1 and by L1, C4 and real Existing ac converter output;When S1 is turned off, the energy being stored on L1 realizes afterflow by C3, D6.Exchange output sine wave bears half Zhou Shi, S1 are turned off and S2 is open-minded, and C3 filters to realize that ac converter is exported by S2 and by L3, C4;When S2 is turned off, it is stored in The energy of L3 realizes afterflow by C5, D5.
From the foregoing, it can be seen that all high-frequency works of power switch pipe and can be used MOSFET, also may be used when switching frequency is relatively low Using IGBT, power diode also all high-frequency works and fast recover or SiC can be used(Carborundum)Etc. types.Meanwhile by In power switch pipe and its bi-directional conductive of body diode, it will be apparent that this DC/AC module can realize the two-way flow of energy, So as to which system has active output and reactive power compensation planning.It is respectively constituted by S1 and D6, S2 and D5 or S3 and D8, S4 and D7 In same inverter bridge leg or converter bridge arm, inside is only connected in series by power switch pipe and power diode, may be not present Switching tube is directly connected, and this mode can eliminate Switch Cut-through risk, improve functional reliability.The power of half-bridge inversion circuit is opened It is half of power frequency period work to close pipe and power diode, and HF switch works in half of power frequency period, and two-way The power switch pipe and power diode of One Buck-Boost converter body work respectively according to C5, C3 terminal voltage situation, in addition power Circuit only there are one power tube it is open-minded, so as to reduce power attenuation, improve transfer efficiency, while reduce power device thermal stress, Further improve functional reliability.Power switch pipe is switched on or off instruction and comes from control circuit or MCU(Microcontroller), half Bridge inverter circuit is modulated to further improve transfer efficiency using Unipolar SPWM.The a ends of DC/AC modules exchange output N Line is directly connected to component cathode, is completely eliminated common mode leakage current, is improved security of system.
Embodiment shown in Fig. 7 can be further simplified, and remove no dead-zone technique, so as to form the ground connection of cathode shown in Fig. 9 system The DC/AC module embodiments 3 of system, wherein C5 be dc-link capacitance, S1, S2, S3, S4, S5 be power switch pipe, D1, D2, D3, D4, D5 are respectively its body diode, and C3 is striding capacitance, and L1 is ac filter inductance, and C4 is ac filter capacitance.This Embodiment externally has a, b, c port, is electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.Exchange output sine wave positive half cycle When, S1, S3, S4 are opened at this time and S2, S5 are turned off, and C5 is charged by the body diode D3 of S1, S3 to C3, while passes through S1, S4 And filtered by L1, C4 and realize that ac converter exports, inverter bridge leg midpoint d is to the voltage value at a ends and C5 terminal voltages etc. at this time Current potential and with "+1 " refer to;When S4 is turned off, the body diode D3 that C5 continues through S1, S3 charges to C3, while is stored on L1 Energy afterflow is realized by the body diode D5 of S3, S5, d is zero to the voltage value at a ends and is referred to " 0 " at this time.It exchanges defeated When going out sine wave negative half period, S1, S3, S4 are turned off and S2, S5 are open-minded, and the storage energy of C3 is filtered by S2, S5 and by L1, C4 And realizing that ac converter exports, inverter bridge leg midpoint d mutually refers to the voltage value at a ends with C3 terminal voltages with " -1 " instead at this time; When S5 is turned off, be stored in the energy of L1 and afterflow realized by the body diode D4 of S2, S4, at this time d to the voltage value at a ends be zero and It is referred to " 0 ".When S1, S3 are opened, C3 is to be connected in parallel substantially with C5, thus can reduce DC bus current ripple.Meanwhile Inverter bridge leg midpoint d generates a ends "+1 ", " 0 ", " -1 " three kinds of level, thus realizes the three level output of inverter circuit.
From the foregoing, it can be seen that during exchange output sine wave positive half cycle, power switch tube S 1, S3 are only the work of power frequency low frequency switch And IGBT device can be used, S4 can be used MOSFET for high-frequency work during this period, can also be used when switching frequency is relatively low IGBT;During exchange output sine wave negative half period, power switch tube S 2 is only the work of power frequency low frequency switch and IGBT device can be used, MOSFET can be used for high-frequency work during this period in S5, and IGBT can also be used when switching frequency is relatively low.Simultaneously as power is opened Close the bi-directional conductive of pipe and its body diode, it will be apparent that this DC/AC module can realize the two-way flow of energy, so as to system With active output and reactive power compensation planning.Five power switch pipes are half of power frequency period work, and two of which power is opened It closes pipe HF switch in half of power frequency period to work, in addition power tube is open-minded there are two loop of power circuit, so as to reduce power Loss improves transfer efficiency, while reduces power device thermal stress, improves functional reliability.Power switch pipe is switched on or off Instruction comes from control circuit or MCU(Microcontroller), by using Unipolar SPWM modulate realize output "+1 ", " 0 ", "- 1 " three kind of level, so as to reduce internal passive the device such as size of inductance, capacitance and volume, alleviate inverter weight, and And further improve transfer efficiency.The a ends of DC/AC modules exchange output N lines and are directly connected to component cathode, completely eliminate altogether Mode ship electric current improves security of system.Meanwhile the high-frequency tube of internal circuit using MOSFET and power frequency pipe using IGBT, one Determine to reduce DC/AC module costs in degree.
Embodiment shown in Fig. 8 can be further simplified, and remove no dead-zone technique, so as to form the ground connection of cathode shown in Figure 10 system The DC/AC module embodiments 4 of system, wherein C5 be dc-link capacitance, S1, S2, S3, S4 be power switch pipe, D1, D2, D3, D4 Respectively its body diode, C3 are DC filter capacitor, and L1 is ac filter inductance, and C4 is ac filter capacitance, L2 Buck- Boost energy storage inductors.S3, S4, L2 form two-way One Buck-Boost converter body, and C5, C3, S1, S2, L1, C4 form semi-bridge inversion Circuit.This embodiment externally has a, b, c port, is electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.C5 terminal voltages are more than During C3 terminal voltages, S3 is opened at this time and S4 is turned off, and C5 is charged by S3 to L2;When S3 is turned off, the energy for being stored in L2 passes through D4 It charges to C3.When otherwise C5 terminal voltages are less than C3 terminal voltages, S4 is opened at this time and S3 is turned off, and C3 is charged by S4 to L2;S4 is closed When disconnected, the energy for being stored in L2 is charged by D3 to C5.So as to by the continuous HF switch course of work, finally realize C5, C3 terminal voltage equipotentials, this is also the precondition that half-bridge inversion circuit effectively works, finally achievable half-bridge inversion circuit note Enter load or the smaller direct-current component of AC network.During exchange output sine wave positive half cycle, S1 is opened at this time and S2 is closed Disconnected, C5 filters to realize that ac converter is exported by S1 and by L1, C4;When S1 is turned off, be stored in energy on L1 by C3, The body diode D2 of S2 realizes afterflow.During exchange output sine wave negative half period, S1 is turned off and S2 is open-minded, and C3 is by S2 and passes through L1, C4 are filtered and are realized ac converter and export;When S2 is turned off, the energy for being stored in L1 is realized by the body diode D1 of C5, S1 Afterflow.
From the foregoing, it can be seen that all high-frequency works of power switch pipe and can be used MOSFET, also may be used when switching frequency is relatively low Use IGBT.Simultaneously as the bi-directional conductive of power switch pipe and its body diode, it will be apparent that this DC/AC module can be real The two-way flow of existing energy, so as to which system has active output and reactive power compensation planning.The power switch pipe of half-bridge inversion circuit It is half of power frequency period work with power diode, and HF switch works in half of power frequency period, and two-way Buck- The power switch pipe of Boost works respectively according to C5, C3 terminal voltage situation, and in addition only there are one power tubes for loop of power circuit It is open-minded, so as to reduce power attenuation, improve transfer efficiency, while reduce power device thermal stress, improve functional reliability.Power Switching tube is switched on or off instruction and comes from control circuit or MCU(Microcontroller), half-bridge inversion circuit is using Unipolar SPWM It modulates to further improve transfer efficiency.The a ends of DC/AC modules exchange output N lines and are directly connected to component cathode, completely It eliminates common mode leakage current, improve security of system.
From the foregoing it will be appreciated that high-performance three-phase and single-phase photovoltaic inverter needs form plus earth system according to practical application System, but the topological structure and negative ground system of its internal DC/DC modules and DC/AC modules are not fully identical, Figure 11-figure 15 embodiment is i.e. for positive ground system.
In the DC/DC module embodiments of positive ground system shown in Figure 11, another negative pressure output Boost boostings are employed Converter, wherein C1 are DC filter capacitor, and L5 is Boost energy storage inductors, and S9 is power switch pipe, D9 is its body diode, D10 is power diode, and D11 is frequency bypass diode, and C2 is dc-link capacitance.This converter externally has A, B, C Port is electrically connected respectively with A, B of Fig. 4, Fig. 5, C-terminal.DC input voitage is less than in the case of output voltage, when S9 is opened, L5 energy storage, output energy are provided by C2;When S9 is turned off, the energy being stored on L5 is discharged to output by D10 and charged to C2, The instruction that is switched on or off of power switch tube S 9 comes from control circuit or MCU(Microcontroller).DC input voitage is more than defeated Go out under voltage condition, converter realizes bypass functionality by D11.It is pointed out that the switching frequency one of DC/DC converters As it is higher, therefore MOSFET can be used in power switch pipe(MOS memory), then may be used when switching frequency is relatively low Use IGBT(Insulated gate bipolar transistor), and power diode is using fast recovery or SiC(Carborundum)Etc. types.DC/DC Above-mentioned negative pressure output Boost converter had both can be used in the internal topology of module, it is possible to use negative pressure output Buck drops Other various types isolated forms or non-isolation type DC/DC converters also can be used in buckling parallel operation.
In the DC/AC module embodiments 1 of positive ground system shown in Figure 12, striding capacitance and full-bridge inverting are equally employed For circuit without dead-zone technique, wherein C5 is dc-link capacitance, and S1, S2, S3, S4, S5 are power switch pipe, D1, D2, D3, D4, D5 Respectively its body diode, C3 are striding capacitance, and D6, D7 are power diode, and L1, L2 are ac filter inductance, and C4 is exchange Filter capacitor.This embodiment externally has a, b, c port, is electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.Exchange output During sine wave negative half period, S1, S3, S5 are opened at this time and S2, S4 are turned off, and C5 is charged by the body diode D3 of S1, S3 to C3, It filters to realize that ac converter is exported by S1, S5 and by L2, C4 simultaneously, inverter bridge leg midpoint e is to the voltage value at a ends at this time It is mutually referred to instead with " -1 " with C5 terminal voltages;When S5 is turned off, the body diode D3 that C5 continues through S1, S3 charges to C3, simultaneously It is stored in energy on L2 and afterflow is realized by S3, D6, e is zero to the voltage value at a ends and is referred to " 0 " at this time.Exchange output During sine wave positive half cycle, S1, S3, S5 shut-off and S2, S4 are open-minded, the storage energy of C3 by S2, S4 and by L1, C4 filter and Realize ac converter output, inverter bridge leg midpoint d refers to the voltage value at a ends with C3 terminal voltages equipotential with "+1 " at this time; It when S4 is turned off, is stored in the energy of L1 and afterflow is realized by S2, D7, d is zero to the voltage value at a ends and is referred to " 0 " at this time. When S1, S3 are opened, C3 is to be connected in parallel substantially with C5, thus can reduce DC bus current ripple.Meanwhile in inverter bridge leg Point d and e generates a ends "+1 ", " 0 ", " -1 " three kinds of level, thus realizes the three level output of inverter circuit.
From the foregoing, it can be seen that during exchange output sine wave negative half period, power switch tube S 1, S3 are only the work of power frequency low frequency switch And IGBT device can be used, S5 can be used MOSFET for high-frequency work during this period, can also be used when switching frequency is relatively low Fast recovery or SiC also can be used for high-frequency work during this period in IGBT, D6(Carborundum)Etc. types;Exchange output sine wave is just During half cycle, power switch tube S 2 is only the work of power frequency low frequency switch and IGBT device can be used, and S4 is high-frequency work during this period And MOSFET can be used, IGBT, D7 can also be used also to can be used during this period for high-frequency work fast extensive when switching frequency is relatively low Multiple or SiC(Carborundum)Etc. types.Simultaneously as the bi-directional conductive of power switch pipe and its body diode, it will be apparent that this DC/AC modules can realize the two-way flow of energy, so as to which system has active output and reactive power compensation planning.By S4 and D7 or In the same inverter bridge leg that S5 and D6 is respectively constituted, inside be only connected in series by power switch pipe and power diode, without It directly connects there are switching tube, also referred to as without dead-zone technique, this mode can eliminate Switch Cut-through risk, improve reliable operation Property.Five power switch pipes and two power diodes are the work of half power frequency period, two of which power switch pipe, two Power diode HF switch in half of power frequency period works, and in addition power tube is open-minded there are two loop of power circuit, so as to drop Low-power consumption improves transfer efficiency, while reduces power device thermal stress, further improves functional reliability.Power switch Pipe is switched on or off instruction and comes from control circuit or MCU(Microcontroller), modulated by using Unipolar SPWM and realize output "+1 ", " 0 ", " -1 " three kinds of level, so as to reduce internal passive the device such as size of inductance, capacitance and volume, alleviate Inverter weight, and further improve transfer efficiency.The a ends of DC/AC modules exchange output N lines and directly connect with component anode It connects, completely eliminates common mode leakage current, improves security of system.Meanwhile the high-frequency tube of internal circuit uses MOSFET and power frequency pipe Using IGBT, DC/AC module costs are reduced to a certain extent.
In the DC/AC module embodiments 2 of positive ground system shown in Figure 13, two-way Buck-Boost conversion is equally employed Without dead-zone technique, wherein C5 is dc-link capacitance for device and high-frequency switch circuit, and S1, S2, S3, S4 are power switch pipe, D1, D2, D3, D4 are respectively its body diode, and C3 is DC filter capacitor, and D5, D6, D7, D8 are power diode, and L1, L3 are exchange Filter inductance, C4 are ac filter capacitance, and L2, L4 are Buck-Boost energy storage inductors.S3, S4, D7, D8, L2, L4 form two-way One Buck-Boost converter body, C5, C3, S1, S2, D5, D6, L1, L3, C4 form half-bridge inversion circuit.This embodiment externally has There are a, b, c port, be electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.C5 terminal voltages be more than C3 terminal voltages when, at this time S4 open, And S3 is turned off, C5 is charged by S4 to L4;When S4 is turned off, the energy for being stored in L4 is charged by D7 to C3;Otherwise C5 terminal voltages During less than C3 terminal voltages, S3 is opened at this time and S4 is turned off, and C3 is charged by S3 to L2;When S3 is turned off, the energy for being stored in L2 leads to D8 is crossed to charge to C5.So as to by the continuous HF switch course of work, finally realize C5, C3 terminal voltage equipotential, this is also The precondition that half-bridge inversion circuit effectively works, finally achievable half-bridge inversion circuit injection load or AC network are smaller Direct-current component.During exchange output sine wave positive half cycle, S1 is opened at this time and S2 is turned off, and C3 is filtered by S1 and by L1, C4 Ripple and realize ac converter export;When S1 is turned off, the energy being stored on L1 realizes afterflow by C5, D6.Exchange output is sinusoidal During ripple negative half period, S1 is turned off and S2 is open-minded, and C5 filters to realize that ac converter is exported by S2 and by L3, C4;When S2 is turned off, The energy for being stored in L3 realizes afterflow by C3, D5.
From the foregoing, it can be seen that all high-frequency works of power switch pipe and can be used MOSFET, also may be used when switching frequency is relatively low Using IGBT, power diode also all high-frequency works and fast recover or SiC can be used(Carborundum)Etc. types.Meanwhile by In power switch pipe and its bi-directional conductive of body diode, it will be apparent that this DC/AC module can realize the two-way flow of energy, So as to which system has active output and reactive power compensation planning.It is respectively constituted by S1 and D6, S2 and D5 or S3 and D8, S4 and D7 In same inverter bridge leg or converter bridge arm, inside is only connected in series by power switch pipe and power diode, may be not present Switching tube is directly connected, and this mode can eliminate Switch Cut-through risk, improve functional reliability.The power of half-bridge inversion circuit is opened It is half of power frequency period work to close pipe and power diode, and HF switch works in half of power frequency period, and two-way The power switch pipe and power diode of One Buck-Boost converter body work respectively according to C5, C3 terminal voltage situation, in addition power Circuit only there are one power tube it is open-minded, so as to reduce power attenuation, improve transfer efficiency, while reduce power device thermal stress, Further improve functional reliability.Power switch pipe is switched on or off instruction and comes from control circuit or MCU(Microcontroller), half Bridge inverter circuit is modulated to further improve transfer efficiency using Unipolar SPWM.The a ends of DC/AC modules exchange output N Line is directly connected to component anode, is completely eliminated common mode leakage current, is improved security of system.
Embodiment shown in Figure 12 can be further simplified, and remove no dead-zone technique, so as to form plus earth shown in Figure 14 The DC/AC module embodiments 3 of system, wherein C5 be dc-link capacitance, S1, S2, S3, S4, S5 be power switch pipe, D1, D2, D3, D4, D5 are respectively its body diode, and C3 is striding capacitance, and L1 is ac filter inductance, and C4 is ac filter capacitance.This Embodiment externally has a, b, c port, is electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.Exchange output sine wave negative half period When, S1, S3, S5 are opened at this time and S2, S4 are turned off, and C5 is charged by the body diode D3 of S1, S3 to C3, while passes through S1, S5 And filtered by L1, C4 and realize that ac converter exports, inverter bridge leg midpoint d is to the voltage value at a ends and C5 terminal voltage phases at this time It is referred to instead with " -1 ";When S5 is turned off, the body diode D3 that C5 continues through S1, S3 charges to C3, while is stored on L1 Energy realizes afterflow by S3, D4, and d is zero and is referred to " 0 " to the voltage value at a ends at this time.Exchange output sine wave positive half cycle When, S1, S3, S5 are turned off and S2, S4 are open-minded, and the storage energy of C3 filters to realize ac converter by S2, S4 and by L1, C4 It exports, inverter bridge leg midpoint d refers to the voltage value at a ends with C3 terminal voltages equipotential with "+1 " at this time;When S4 is turned off, storage Afterflow is realized by S2, D5 in the energy of L1, d is zero and is referred to " 0 " to the voltage value at a ends at this time.When S1, S3 are opened, C3 Substantially with C5 to be connected in parallel, thus DC bus current ripple can be reduced.Meanwhile inverter bridge leg midpoint d to a ends generate "+ 1 ", " 0 ", " -1 " three kinds of level, thus realize the three level output of inverter circuit.
From the foregoing, it can be seen that during exchange output sine wave negative half period, power switch tube S 1, S3 are only the work of power frequency low frequency switch And IGBT device can be used, S5 can be used MOSFET for high-frequency work during this period, can also be used when switching frequency is relatively low IGBT;During exchange output sine wave positive half cycle, power switch tube S 2 is only the work of power frequency low frequency switch and IGBT device can be used, MOSFET can be used for high-frequency work during this period in S4, and IGBT can also be used when switching frequency is relatively low.Simultaneously as power is opened Close the bi-directional conductive of pipe and its body diode, it will be apparent that this DC/AC module can realize the two-way flow of energy, so as to system With active output and reactive power compensation planning.Five power switch pipes are half of power frequency period work, and two of which power is opened It closes pipe HF switch in half of power frequency period to work, in addition power tube is open-minded there are two loop of power circuit, so as to reduce power Loss improves transfer efficiency, while reduces power device thermal stress, improves functional reliability.Power switch pipe is switched on or off Instruction comes from control circuit or MCU(Microcontroller), by using Unipolar SPWM modulate realize output "+1 ", " 0 ", "- 1 " three kind of level, so as to reduce internal passive the device such as size of inductance, capacitance and volume, alleviate inverter weight, and And further improve transfer efficiency.The a ends of DC/AC modules exchange output N lines and are directly connected to component anode, completely eliminate altogether Mode ship electric current improves security of system.Meanwhile the high-frequency tube of internal circuit using MOSFET and power frequency pipe using IGBT, one Determine to reduce DC/AC module costs in degree.
Embodiment shown in Figure 13 can be further simplified, and remove no dead-zone technique, so as to form plus earth shown in Figure 15 The DC/AC module embodiments 4 of system, wherein C5 be dc-link capacitance, S1, S2, S3, S4 be power switch pipe, D1, D2, D3, D4 is respectively its body diode, and C3 is DC filter capacitor, and L1 is ac filter inductance, and C4 is ac filter capacitance, and L2 is Buck-Boost energy storage inductors.S3, S4, L2 form two-way One Buck-Boost converter body, and C5, C3, S1, S2, L1, C4 form half-bridge Inverter circuit.This embodiment externally has a, b, c port, is electrically connected respectively with a, b, c end of Fig. 4, Fig. 5.C5 terminal voltages During more than C3 terminal voltages, S4 is opened at this time and S3 is turned off, and C5 is charged by S4 to L2;When S4 is turned off, the energy for being stored in L2 leads to D3 is crossed to charge to C3;When otherwise C5 terminal voltages are less than C3 terminal voltages, S3 is opened at this time and S4 is turned off, and C3 is charged by S3 to L2; When S3 is turned off, the energy for being stored in L2 is charged by D4 to C5.So as to pass through the continuous HF switch course of work, final realization C5, C3 terminal voltage equipotential, this is also the precondition that half-bridge inversion circuit effectively works, and half-bridge inversion circuit finally can be achieved Injection load or the smaller direct-current component of AC network.During exchange output sine wave positive half cycle, S1 is opened at this time and S2 is closed Disconnected, C3 filters to realize that ac converter is exported by S1 and by L1, C4;When S1 is turned off, be stored in energy on L1 by C5, D2 realizes afterflow.During exchange output sine wave negative half period, S1 is turned off and S2 is open-minded, and C5 is filtered by S2 and by L1, C4 and real Existing ac converter output;When S2 is turned off, the energy for being stored in L1 realizes afterflow by C3, D1.
From the foregoing, it can be seen that all high-frequency works of power switch pipe and can be used MOSFET, also may be used when switching frequency is relatively low Using IGBT, power diode also all high-frequency works and fast recover or SiC can be used(Carborundum)Etc. types.Meanwhile by In power switch pipe and its bi-directional conductive of body diode, it will be apparent that this DC/AC module can realize the two-way flow of energy, So as to which system has active output and reactive power compensation planning.The power switch pipe and power diode of half-bridge inversion circuit are half A power frequency period work, and HF switch works in half of power frequency period, and the power of two-way One Buck-Boost converter body is opened It closes pipe and power diode works respectively according to C5, C3 terminal voltage situation, in addition power tube is open-minded there are one loop of power circuit, from And reduce power attenuation, improve transfer efficiency, while reduce power device thermal stress, further improve functional reliability.Power Switching tube is switched on or off instruction and comes from control circuit or MCU(Microcontroller), half-bridge inversion circuit is using Unipolar SPWM It modulates to further improve transfer efficiency.The a ends of DC/AC modules exchange output N lines and are directly connected to component anode, completely It eliminates common mode leakage current, improve security of system.
With reference to Fig. 4, Fig. 6 and Fig. 7, three-phase photovoltaic power generation system such as Figure 16 institutes of cathode of embodiment of the present invention ground connection are can obtain Show, used n DC/DC module to realize that photovoltaic system n road MPPT are tracked, while three DC/AC modules has been used to realize Three-phase alternating current exports, and the exchange of DC/AC modules, which is exported after the neutral conductor is connected with photovoltaic module, string formation or array cathode, to be grounded.Class Like Fig. 5, DC/AC modules can be reduced and obtain the single-phase photovoltaic power generation system of cathode ground connection.
With reference to Fig. 4, Figure 11 and Figure 12, three-phase photovoltaic power generation system such as Figure 17 of plus earth of the embodiment of the present invention can obtain It is shown, the DC/DC modules of n negative pressure output have been used to realize that photovoltaic system n road MPPT are tracked, while have used three DC/ AC modules are to realize that three-phase alternating current exports, the exchange output neutral conductor and photovoltaic module, string formation or array anode phase of DC/AC modules It is grounded after even.Similar Fig. 5 can reduce DC/AC modules and obtain the single-phase photovoltaic power generation system of cathode ground connection.
It is non-isolated that the photovoltaic generating system for the component polarity ground connection that above example of the present invention proposes belongs to transless Photovoltaic generating system, critical component is matched solution for high-performance photovoltaic inverter, by DC/DC modules and DC/AC module structures Into.DC/DC modules are suitable for wider DC input voitage scope, and realize that photovoltaic MPPT is tracked.The exchange output of DC/AC modules The neutral conductor is grounded after being connected with component cathode or anode, and an internal power switching tube part works in high frequency, another part work In power frequency low frequency, high-frequency tube uses MOSFET and power frequency pipe uses IGBT, and uses Unipolar SPWM modulation to export three electricity It is flat, while the connection mode of power switch pipe and power diode can eliminate Switch Cut-through risk in inverter bridge leg.It can be according to reality Border needs flexible configuration DC/DC and DC/AC module number, it can be achieved that photovoltaic system multichannel MPPT functions, and suitable for single-phase and Three-phase photovoltaic power generation system.Common mode leakage current is completely eliminated to assure the absolute personal safety of terminal user and operation maintenance personnel;Tool There is the universality for components such as all kinds of crystal silicons, films, improve component PID effects to improve photovoltaic system generated energy, and in rain Prevent inverter protection from shutting down under it and wet environment;Topological structure realizes output as three level simultaneously, so as to improve conversion effect Rate reduces internal passive device volume and weight;In addition the reliability, reduction system cost, improvement for improving system work are defeated Go out current waveform quality, reduce electromagnetic interference.Therefore, this security of system is more preferable, transfer efficiency higher, cost are lower, fits For in various grid types, off-network type and accumulation energy type inverter.
The photovoltaic generating system of the component polarity ground connection of above example of the present invention belongs to transless non-isolation type photovoltaic Electricity generation system, mainly has the following advantages and effect:
1st, the exchange output neutral conductor of DC/AC modules is grounded after being connected with component cathode or anode, completely eliminates common mode leakage current To assure the absolute personal safety of terminal user and operation maintenance personnel;
2nd, also improve output current wave quality while completely eliminating common mode leakage current, reduce electromagnetic interference;
3rd, have for all kinds of crystal silicons, the universality of film assembly, improve component PID effects to improve system generated energy, and Prevent inverter protection from shutting down under rainy day and wet environment;
4th, Unipolar SPWM modulation realizes that inverter output is three level, so as to improve transfer efficiency, reduce internal passive device Volume and weight;
5th, an internal power switching tube part works in high frequency, another part works in power frequency, high-frequency tube work using MOSFET Frequency pipe uses IGBT, so as to reduce system cost;
6th, the connection mode of power switch pipe and power diode can eliminate Switch Cut-through risk and power device in inverter bridge leg The work of power frequency half period reduces thermal stress, so as to improve inverter functional reliability;
7th, can flexible configuration DC/DC and DC/AC module numbers according to actual needs, to adapt to wider DC input voitage scope, Photovoltaic multichannel MPPT tracking can be achieved, and suitable for single-phase and three-phase photovoltaic power generation system.

Claims (10)

1. a kind of photovoltaic generating system of component polarity ground connection, which is characterized in that including at least one component, with component count phase Same DC/DC modules and at least one DC/AC modules;One end ground connection of component, another input for terminating corresponding DC/DC modules End;One output termination dc bus of DC/DC modules, another output head grounding;One input termination of DC/AC modules is straight Flow busbar, another input end grounding;The ac output end ground connection of DC/AC modules.
2. the photovoltaic generating system of component polarity ground connection according to claim 1, which is characterized in that including at least one institute The component stated and DC/AC modules described in three and with three-phase voltage increasing transformer, the DC/AC modules composition three-phase light described in three Lie prostrate inverter;Three ac output ends of three-phase photovoltaic inverter connect corresponding three-phase voltage increasing transformer primary side winding respectively, and three The neutral ground of phase step-up transformer primary side winding.
3. the photovoltaic generating system of component polarity ground connection according to claim 2, which is characterized in that component polarity ground connection Photovoltaic generating system includes the photovoltaic generating system of component cathode ground connection and the photovoltaic generating system of component plus earth;For group The photovoltaic generating system of part cathode ground connection, the anode of component connect the anode of corresponding DC/DC module inputs;DC/DC modules are defeated The anode of outlet connects dc bus, the cathode ground connection of output terminal;The anode of DC/AC module inputs connects dc bus, input terminal Cathode ground connection;For the photovoltaic generating system of component plus earth, the cathode of component connects corresponding DC/DC module inputs Cathode;The cathode of DC/DC module output terminals connects dc bus, plus earth;The cathode of DC/AC module inputs meets direct current mother Line, the plus earth of input terminal.
4. the photovoltaic generating system of component polarity ground connection according to claim 1, which is characterized in that DC/DC modules are liter Buckling parallel operation, including the first DC filter capacitor, boost inductance, boosted switch pipe, booster diode, the first dc bus electricity Hold and bypass diode, the first DC filter capacitor are connected between the positive electrode and negative electrode of DC/DC module inputs, the first direct current is female Line capacitance is connected between the positive electrode and negative electrode of DC/DC module output terminals;For the photovoltaic generating system of component cathode ground connection, boosting The anode of first termination DC/DC module inputs of inductance, the anode of the second termination booster diode, the cathode of booster diode Connect the anode of DC/DC module output terminals;The second end of the high potential termination boost inductance of boosted switch pipe, low potential termination DC/ The cathode of DC module inputs;The anode of bypass diode connects the first end of boost inductance, and cathode connects the cathode of booster diode; For the photovoltaic generating system of component plus earth, the cathode of the first termination DC/DC module inputs of boost inductance, second end The cathode of booster diode is connect, the anode of booster diode connects the cathode of DC/DC module output terminals;The low potential of boosted switch pipe The second end of boost inductance is terminated, high potential terminates the anode of DC/DC module inputs;The cathode of bypass diode connects boosting electricity The first end of sense, anode connect the anode of booster diode;DC input voitage is less than in the case of output voltage, and boosted switch pipe is opened When logical, boost inductance energy storage, output energy provides by the first dc-link capacitance;When boosted switch pipe turns off, boosting is stored in Energy on inductance is released to output terminal by booster diode, and charges to the first dc-link capacitance;DC input voitage In the case of output voltage, converter realizes bypass functionality by bypass diode.
5. the photovoltaic generating system of component polarity ground connection according to claim 1, which is characterized in that DC/AC modules include Second dc-link capacitance, first switch pipe, second switch pipe, the 3rd switching tube, the 4th switching tube, the 5th switching tube, first Striding capacitance, the 6th diode, the 7th diode, the first ac filter inductance, the second ac filter inductance and the first exchange filter Ripple capacitance, the high potential of second switch pipe terminate the hot end of the 4th switching tube and the cathode of the 6th diode, second switch The low potential of pipe terminates the hot end of the 3rd switching tube;The low potential of 3rd switching tube terminates the anode and the of the 7th diode The cold end of five switching tubes, the cathode of the 7th diode connect the cold end of the 4th switching tube, the high potential of the 5th switching tube Terminate the anode of the 6th diode;First striding capacitance is connected on the hot end of second switch pipe and the low potential of the 3rd switching tube Between end;The cold end of first the 4th switching tube of termination of the first ac filter inductance, the second of the first ac filter inductance Terminate the second end of the second ac filter inductance, the hot end of the first the 5th switching tube of termination of the second ac filter inductance; The second end of first the first ac filter inductance of termination of the first ac filter capacitance, the second termination of the first ac filter capacitance The direct-flow input end of DC/AC modules and ground connection, the second dc-link capacitance be connected on DC/AC modules direct current input ungrounded end with Between the cold end of second switch pipe;For the photovoltaic generating system of component cathode ground connection, the 3rd switching tube includes two pole of body Pipe, the anode of the high potential termination DC/AC modules direct current input of first switch pipe, low potential terminate the high potential of second switch pipe End, the cathode of the low potential termination DC/AC modules direct current input of second switch pipe and ground connection;For the photovoltaic of component plus earth Electricity generation system, second switch pipe include body diode, and the low potential termination DC/AC modules direct current input of first switch pipe is born Pole, high potential terminate the cold end of the 3rd switching tube, and the high potential termination DC/AC modules direct current input of the 3rd switching tube is just Pole is simultaneously grounded.
6. the photovoltaic generating system of component polarity ground connection according to claim 5, which is characterized in that connect for component cathode The photovoltaic generating system on ground, when the exchange of DC/AC modules exports sine wave positive half cycle, first switch pipe, the 3rd switching tube and the 4th Switching tube is open-minded, and second switch pipe and the shut-off of the 5th switching tube, the second dc-link capacitance are opened by first switch pipe and the 3rd The body diode for closing pipe charges to the first striding capacitance, while by first switch pipe and the 4th switching tube and by the first exchange Filter inductance and the first ac filter capacitance realize ac converter output;When 4th switching tube turns off, the second dc-link capacitance The body diode for continuing through first switch pipe and the 3rd switching tube charges to the first striding capacitance, while is stored in the first exchange Energy on filter inductance realizes afterflow by the 3rd switching tube and the 7th diode;DC/AC modules exchange output sine wave is born During half cycle, first switch pipe, the 3rd switching tube and the shut-off of the 4th switching tube, second switch pipe and the 5th switching tube are open-minded, and first The storage energy of striding capacitance is by second switch pipe and the 5th switching tube and by the second ac filter inductance and the first exchange Filter capacitor realizes ac converter output;When 5th switching tube turns off, the energy being stored on the second ac filter inductance passes through Second switch pipe and the 6th diode realize afterflow;For the photovoltaic generating system of component plus earth, the exchange of DC/AC modules When exporting sine wave negative half period, first switch pipe, second switch pipe and the 5th switching tube are open-minded, the 3rd switching tube, the 4th switch Pipe turns off, and the second dc-link capacitance is filled by the body diode and first switch pipe of second switch pipe to the first striding capacitance Electricity, while realized by first switch pipe, the 5th switching tube and by the second ac filter inductance and the first ac filter capacitance Ac converter exports;5th switching tube turn off when, the second dc-link capacitance continue through second switch pipe body diode and First switch pipe charges to the first striding capacitance, while the energy being stored on the second ac filter inductance passes through second switch pipe Afterflow is realized with the 6th diode;DC/AC modules exchange output sine wave positive half cycle when, second switch pipe, first switch pipe and 5th switching tube turns off, and the 3rd switching tube and the 4th switching tube are open-minded, and the energy of the first striding capacitance storage passes through the 3rd switch Pipe, the 4th switching tube simultaneously realize ac converter output by the first ac filter inductance and the first ac filter capacitance;4th opens When closing pipe shut-off, the energy for being stored in the first ac filter inductance passes through the 3rd switching tube, the 7th diode continuousing flow.
7. the photovoltaic generating system of component polarity ground connection according to claim 1, which is characterized in that DC/AC modules include Two-way One Buck-Boost converter body and half-bridge inversion circuit, two-way One Buck-Boost converter body include the 13rd switching tube, the tenth Four switching tubes, the 17th diode, the 18th diode, the 12nd energy storage inductor and the 14th energy storage inductor, semi-bridge inversion electricity Road includes upper capacitance, lower capacitance, the 11st switching tube, the 12nd switching tube, the 15th diode, the 16th diode, the tenth One ac filter inductance, the 13rd ac filter inductance and the second ac filter capacitance;The high potential termination of 13rd switching tube The cathode of 17th diode, low potential terminate the cathode of the 18th diode and the first end of the 12nd energy storage inductor;Tenth The high potential of four switching tubes terminates the anode of the 17th diode and the first end of the 14th energy storage inductor, low potential termination the tenth The anode of eight diodes;Ground terminal and first ac output end of the second end of 12nd energy storage inductor as DC/AC modules, connect The second end of 14th energy storage inductor;The high potential of 11st switching tube terminates the cathode of the 15th diode, low potential termination The cathode of 16th diode and the first end of the 11st ac filter inductance;The high potential termination the 15th of 12nd switching tube The first end of the anode of diode and the 13rd ac filter inductance, low potential terminate the anode of the 16th diode;11st Second ac output end of the second end of ac filter inductance as DC/AC modules, connects the second of the 13rd ac filter inductance End;Second ac filter capacitance is connected between the first ac output end of DC/AC modules and the second ac output end;Upper capacitance Anode connects the hot end of the 13rd switching tube and the hot end of the 11st switching tube, and the cathode of upper capacitance connects DC/AC modules Ground terminal;The anode of lower capacitance connects the cathode of capacitance, and the cathode of lower capacitance connects the cold end and of the 14th switching tube The cold end of 12 switching tubes.
8. the photovoltaic generating system of component polarity ground connection according to claim 7, which is characterized in that connect for component cathode The photovoltaic generating system on ground, upper capacitance are the 3rd dc-link capacitance, the just extremely direct-flow input end of DC/AC modules of upper capacitance Anode, lower capacitance are the 13rd DC filter capacitor;For the photovoltaic generating system of component plus earth, lower capacitance is straight for the 3rd Bus capacitor is flowed, the cathode of lower capacitance is the direct-flow input end cathode of DC/AC modules, and upper capacitance is the 13rd DC filtering electricity Hold;When upper capacitance terminal voltage is more than lower capacitance terminal voltage, the 13rd switching tube is opened, the shut-off of the 14th switching tube, upper capacitance It is charged by the 13rd switching tube to the 12nd energy storage inductor;When 13rd switching tube turns off, the 12nd energy storage inductor is stored in Energy by the 18th diode give lower capacitance charge;When upper capacitance terminal voltage is less than lower capacitance terminal voltage, the 14th opens Pass pipe is opened, the shut-off of the 13rd switching tube, and lower capacitance gives the 14th energy storage inductor to charge by the 14th switching tube;14th opens When closing pipe shut-off, the energy of the 14th energy storage inductor is stored in by the 17th diode to powering on capacity charge;By continuous The HF switch course of work, capacitance, lower capacitance terminal voltage equipotential in realization;During exchange output sine wave positive half cycle, at this time the 11 switching tubes are opened, the shut-off of the 12nd switching tube, and upper capacitance is by the 11st switching tube and by the 11st ac filter electricity Sense and the second ac filter capacitance realize ac converter output;When 11st switching tube turns off, the 11st ac filter is stored in Energy on inductance realizes afterflow by lower capacitance and the 16th diode;During exchange output sine wave negative half period, the 11st opens Close pipe shut-off and the 12nd switching tube is open-minded, lower capacitance is by the 12nd switching tube and by the 13rd ac filter inductance, the Two ac filter capacitances and realize ac converter export;When 12nd switching tube turns off, the 13rd ac filter inductance is stored in Energy pass through upper capacitance and the 15th diode continuousing flow.
9. the photovoltaic generating system of component polarity ground connection according to claim 1, which is characterized in that DC/AC modules include 4th dc-link capacitance, the 21st switching tube, the 22nd switching tube, the 23rd switching tube, the 24th switching tube, 25th switching tube, the 23rd striding capacitance, the 21st ac filter inductance and the 3rd ac filter capacitance, the 20th Four switching tubes and the 25th switching tube respectively include body diode;The 24th switch of high potential termination of 22nd switching tube The hot end of pipe, the low potential of the 22nd switching tube terminate the hot end of the 23rd switching tube;23rd switch The low potential of pipe terminates the cold end of the 25th switching tube, the 25th switch of low potential termination of the 24th switching tube The first end of the hot end of pipe and the 21st ac filter inductance;23rd striding capacitance is connected on the 22nd switching tube Hot end and the 23rd switching tube cold end between;The first end of 3rd ac filter capacitance is as DC/AC moulds First ac output end of block, connects the second end of the 21st ac filter inductance, and the second end of the 3rd ac filter capacitance is made For the second ac output end of DC/AC modules, the ground terminal of DC/AC module direct-flow input ends is connect;4th dc-link capacitance connects Between the ungrounded end of DC/AC modules direct current input and the cold end of the 22nd switching tube;It is grounded for component cathode Photovoltaic generating system, the 23rd switching tube include body diode, the 21st switching tube high potential termination DC/AC modules The anode of direct current input, low potential terminate the hot end of the 22nd switching tube, the low potential termination of the 22nd switching tube The cathode of DC/AC modules direct current input and ground connection;For the photovoltaic generating system of component plus earth, the 22nd switching tube bag Include body diode, the cathode of the low potential termination DC/AC modules direct current input of the 21st switching tube, high potential termination the 20th The cold end of three switching tubes, the anode of the high potential termination DC/AC modules direct current input of the 23rd switching tube and ground connection;It is right When the photovoltaic generating system of component cathode ground connection, DC/AC modules exchange output sine wave positive half cycle, the 21st switching tube, 23rd switching tube and the 24th switching tube are open-minded, and the 22nd switching tube and the shut-off of the 25th switching tube, the 4th is straight Bus capacitor is flowed to charge to the 23rd striding capacitance by the body diode of the 21st switching tube and the 23rd switching tube, It is filtered simultaneously by the 21st switching tube and the 24th switching tube and by the 21st ac filter inductance and the 3rd exchange Ripple capacitance realizes ac converter output;When 24th switching tube turns off, the 4th dc-link capacitance continues through the 21st The body diode of switching tube and the 23rd switching tube charges to the 23rd striding capacitance, while is stored in the 21st exchange Energy on filter inductance realizes afterflow by the body diode of the 23rd switching tube and the 25th switching tube;DC/AC moulds During block exchange output sine wave negative half period, the 21st switching tube, the 23rd switching tube and the shut-off of the 24th switching tube, the 22 switching tubes and the 25th switching tube are open-minded, and the storage energy of the 23rd striding capacitance passes through the 22nd switching tube Ac converter output is realized with the 25th switching tube and by the 21st ac filter inductance and the 3rd ac filter capacitance; When 25th switching tube turns off, it is stored in energy on the 21st ac filter inductance and passes through the 22nd switching tube and the The body diode that 24-carat gold closes pipe realizes afterflow;For the photovoltaic generating system of component plus earth, the exchange of DC/AC modules is defeated When going out sine wave negative half period, the 21st switching tube, the 22nd switching tube and the 25th switching tube are open-minded, and the 23rd opens Guan Guan, the shut-off of the 24th switching tube, the body diode and the 20th that the 4th dc-link capacitance passes through the 22nd switching tube One switching tube gives the 23rd striding capacitance to charge, while by the 21st switching tube, the 25th switching tube and by the 21 ac filter inductance and the 3rd ac filter capacitance realize ac converter output;When 25th switching tube turns off, the Four dc-link capacitances continue through the 22nd switching tube body diode and the 21st switching tube to the 23rd fly across Capacitance charges, at the same the energy being stored on the 21st ac filter inductance by the body diode of the 24th switching tube and 22nd switching tube afterflow;During DC/AC modules exchange output sine wave positive half cycle, the 22nd switching tube, the 21st are opened Pipe and the shut-off of the 25th switching tube are closed, the 23rd switching tube and the 24th switching tube are open-minded, the 23rd striding capacitance The energy of storage is handed over by the 23rd switching tube, the 24th switching tube and by the 21st ac filter inductance and the 3rd It flows filter capacitor and realizes ac converter output;When 24th switching tube turns off, the 21st ac filter inductance is stored in Body diode and two ten three switching tube afterflow of the energy by the 23rd switching tube.
10. the photovoltaic generating system of component polarity ground connection according to claim 1, which is characterized in that DC/AC modules include Two-way One Buck-Boost converter body and half-bridge inversion circuit, two-way One Buck-Boost converter body include the 33rd switching tube, the 34 switching tubes and the 32nd energy storage inductor, half-bridge inversion circuit include upper capacitance, lower capacitance, the 31st switching tube, Thirty-twomo closes pipe and the 31st ac filter inductance and the 4th ac filter capacitance, the 31st switching tube, the 30th Two switching tubes, 33 switching tubes and the 34th switching tube respectively include body diode;The hot end of 33rd switching tube The anode of the upper capacitance connect, the hot end of low potential the 34th switching tube of termination and the first of the 32nd energy storage inductor End;Ground terminal and first ac output end of the second end of 32nd energy storage inductor as DC/AC modules;34th switch The cathode of the lower capacitance of low potential termination of pipe;The low potential termination thirty-twomo of 31st switching tube closes the hot end of pipe With the first end of the 31st ac filter inductance;The second end of 31st ac filter inductance as DC/AC modules Two ac output ends, the 4th ac filter capacitance be connected on DC/AC modules the first ac output end and the first ac output end it Between;The anode of upper capacitance connects the hot end of the 33rd switching tube and the hot end of the 31st switching tube, upper capacitance Cathode connects the ground terminal of DC/AC modules;The anode of lower capacitance connects the cathode of capacitance, and the cathode of lower capacitance connects the 34th switch The cold end and thirty-twomo of pipe close the cold end of pipe;For the photovoltaic generating system of component cathode ground connection, upper capacitance For the 5th dc-link capacitance, upper capacitance just extremely the direct-flow input end anode of DC/AC modules, lower capacitance are straight for the 33rd Flow filter capacitor;For the photovoltaic generating system of component plus earth, lower capacitance is the 5th dc-link capacitance, and lower capacitance is born The extremely direct-flow input end cathode of DC/AC modules, upper capacitance are the 33rd DC filter capacitor;When upper capacitance terminal voltage is more than During lower capacitance terminal voltage, the 33rd switching tube is opened, the shut-off of the 34th switching tube, and upper capacitance passes through the 33rd switching tube It charges to the 32nd energy storage inductor;When 33rd switching tube turns off, the energy for being stored in the 32nd energy storage inductor passes through The body diode of 34 switching tubes charges to lower capacitance;When upper capacitance terminal voltage is less than lower capacitance terminal voltage, the 34th opens Pass pipe is opened, the shut-off of the 33rd switching tube, and lower capacitance gives 32 energy storage inductors to charge by the 34th switching tube;3rd When 14 switching tubes turn off, the energy that is stored in is by the body diodes of 33 switching tubes to powering on capacity charge;By continuous The HF switch course of work, capacitance, lower capacitance terminal voltage equipotential in realization;During exchange output sine wave positive half cycle, at this time 31st switching tube is opened, thirty-twomo closes pipe shut-off, and upper capacitance is by the 31st switching tube and by the 31st Ac filter inductance and the 4th ac filter capacitance realize ac converter output;When 31st switching tube turns off, the is stored in Energy on 31 ac filter inductance by the body diode of thirty-twomo pass pipe and lower capacitance and realizes afterflow;Exchange When exporting sine wave negative half period, the 31st switching tube turns off and thirty-twomo pass pipe is open-minded, and lower capacitance passes through the 32nd Switching tube and by the 31st ac filter inductance and with the 4th ac filter capacitance and realize ac converter export;30th When two switching tubes turn off, it is stored in energy on the 31st ac filter inductance and passes through upper capacitance and the 31st switching tube Body diode afterflow.
CN201810069646.3A 2018-01-24 2018-01-24 A kind of photovoltaic generating system of component polarity ground connection Pending CN108110796A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109194175A (en) * 2018-08-27 2019-01-11 江苏大学 A kind of non-isolated grid-connected inverter circuit of type leakage current and control method altogether
CN110098753A (en) * 2019-04-29 2019-08-06 中南大学 A kind of the transless symmetric form mixing transformation device and its modulator approach of multi output
CN110247377A (en) * 2019-04-30 2019-09-17 云南电网有限责任公司电力科学研究院 A kind of power distribution network intelligence low resistance grounding device and its control method

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109194175A (en) * 2018-08-27 2019-01-11 江苏大学 A kind of non-isolated grid-connected inverter circuit of type leakage current and control method altogether
CN110098753A (en) * 2019-04-29 2019-08-06 中南大学 A kind of the transless symmetric form mixing transformation device and its modulator approach of multi output
CN110098753B (en) * 2019-04-29 2021-02-12 中南大学 Multi-output transformer-free symmetric hybrid converter and modulation method thereof
CN110247377A (en) * 2019-04-30 2019-09-17 云南电网有限责任公司电力科学研究院 A kind of power distribution network intelligence low resistance grounding device and its control method

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