CN204103855U - Tandem photovoltaic square formation - Google Patents
Tandem photovoltaic square formation Download PDFInfo
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- CN204103855U CN204103855U CN201420370653.4U CN201420370653U CN204103855U CN 204103855 U CN204103855 U CN 204103855U CN 201420370653 U CN201420370653 U CN 201420370653U CN 204103855 U CN204103855 U CN 204103855U
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Abstract
A kind of tandem photovoltaic square formation, it is characterized in that, described photovoltaic arrays is made up of n photovoltaic group string power unit cascade, n > 1; Photovoltaic group string power cell is composed in series by photovoltaic group string and photovoltaic group string high_voltage isolation power conditioning module.The output of described photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module, export through this photovoltaic group string high_voltage isolation power conditioning module DC/DC isolated port, make the proof voltage > direct current system voltage U smax of each photovoltaic group string power cell.
Description
Technical field
The utility model relates to a kind of photovoltaic group string array of solar photovoltaic generation system.
Background technology
The develop rapidly under the Policy Encouraging of country of current photovoltaic plant, and photovoltaic arrays is one of important composition of photovoltaic generating system, and the energy output of the direct influential system of square formation amount of capacity be made up of the connection in series-parallel of photovoltaic group string.Photovoltaic group string is composed in series by some pieces of photovoltaic modulies, and assembly is the minimum unit of group string, maximum 22 pieces of serial number, and it is withstand voltage that its reason depends primarily on that assembly bears.Group crosstalk pressure≤1000V power after the series connection of current home and abroad assembly is maximum≤7kWp.For improving generating merit amount, two kinds of modes are adopted in current home and abroad: one is form square formation in parallel with the connection in series-parallel of a large amount of photovoltaic group to increase output current, improves square formation power stage in parallel, is exchanging output through inverter inversion, the method is also referred to as centralized or parallel structure, as shown in Figure 4.Two is group serial type photovoltaic generating systems as shown in Figure 5, adopt a kind of group serial type inverter, by many groups group string direct input group serial type inverter, first realize the independent MPPT MPPT maximum power point tracking of each photovoltaic group string, exchange at parallel inverter afterwards and export, this type power is less.To be confluxed cabinet parallel connection by interchange by multiple stage group serial type inverter again for increasing power further.Its essence of two types is all the parallel connection between group string, and voltage is low≤and 1000V, electric current is large, cable machinery loss is large, converging equipment is many, number of cables is many and inverter is the problems such as current mode topological structure power loss is large.Centralized or parallel then requirement group string performance parameter is close, cannot realize again the group independent maximum power point of string (MPPT) and make power loss from motion tracking.Power station, distributed roof area is limit, presses must to consider during equal installation group string to accept or reject for meeting each group of crosstalk, cause limited area loss.
Have again, parallel-connection structure by photovoltaic group string limit, every optical crosstalk volt group connection in series-parallel output voltage is improved according to grid-connected electric pressure, the input starting resistor primary condition of inverter could be met, as in 380v ac grid system, photovoltaic group string output dc voltage > 400v ×
could meet and start inverter basic operating conditions, starting resistor high to obtain electricity limited.
Parallel-connection structure input direct voltage < 1000v equally by photovoltaic group string limit, and can only meet inverter ac output voltage≤400v hierarchical system transless grid-connected, more voltage levels is grid-connected, must export through transformer boost.
Because inverter or DC equipment are divided into current mode or voltage-type in power electronic equipment topological structure, its feature: voltage-type voltage high current is little, and loss is little, and current mode voltage low current is large, loss is large.The parallel-connection structure of same still photovoltaic group string, photovoltaic group string output voltage < 1000v, electric current is large, adopts current mode topological structure inverter.
Thus many groups group string is improved output voltage drop low transmission electric current in series connection and increase power, meet more high-grade transless grid-connected, make photovoltaic group string more low-voltage output energy be utilized, reduce cable and converging equipment quantity, adopt voltage-type topological structure inverter or DC equipment, realize reducing circuit, inverter or DC equipment loss, reduce cable, converging equipment, transformer cost, improve photovoltaic group string generating efficiency, adapt to the demand of distributed, large-sized photovoltaic power station and following middle and high voltage direct current transmission.
The boosting of current photovoltaic system exports three kinds of modes substantially, one for photovoltaic group connection in series-parallel (square formation in parallel) through confluxing, inverter ac transformer boost exports, and mostly is centralized; Two is that the connection in series-parallel of photovoltaic group is confluxed again through transformer boost output through inverter ac, mostly is group string data; Three for volt group connection in series-parallel (square formation in parallel) is through confluxing through DC/DC boosting output.Its essence still utilizes (parallel square formation) in parallel between a large amount of group string to improve photovoltaic arrays power output.
Utility model content
The utility model object overcomes existing utilization group connection in series-parallel to improve the shortcomings such as the method for generated output causes transmission line, corollary equipment loss serious, proposes a kind of tandem photovoltaic square formation.The utility model utilizes the MPPT photovoltaic group string MPPT maximum power point tracking of photovoltaic group string high_voltage isolation power conditioning module, DC/DC, the features such as high_voltage isolation (isolation voltage > Usmax), each photovoltaic group was ganged up photovoltaic group string high_voltage isolation power conditioning module and carried out high_voltage isolation, improve the isolation voltage grade of each photovoltaic group string, by connecting again between photovoltaic group string high_voltage isolation power conditioning module realization group string, improve inverter or DC equipment input voltage, reduce transmission current and increase generated output reduction loss, meet connecting again of different capacity photovoltaic group string power simultaneously, realize photovoltaic DC high-voltage transmission.
The utility model is by the following technical solutions:
The utility model tandem photovoltaic square formation is made up of n photovoltaic group string power unit cascade, n > 1.Photovoltaic group string power cell is composed in series by photovoltaic group string and photovoltaic group string high_voltage isolation power conditioning module.
In photovoltaic group string power cell, the output of described photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module, exports through this photovoltaic group string high_voltage isolation power conditioning module DC/DC isolated port.Photovoltaic group string high_voltage isolation power conditioning module has a communication interface, for connecting fiber or wireless communication module.The output of this photovoltaic group string high_voltage isolation power conditioning module and communication interface are equally also output and the communication interface of photovoltaic group string power cell.Photovoltaic group string through the magnitude of voltage of photovoltaic group string high_voltage isolation power conditioning module isolation and amplifier be the isolation voltage value of photovoltaic group string power cell.This photovoltaic group string high_voltage isolation power conditioning module DC/DC isolated port output voltage Un is also the output voltage values of photovoltaic group string power cell.Due to adding of photovoltaic group string high_voltage isolation power conditioning module, make the isolation voltage > Usmax of photovoltaic group string power cell.
Described Usmax is also referred to as direct current system voltage.Usmax=U1max+U2max+U3max ... ,+Unmax, U1max, U2max ..., Unmax is the maximum of each photovoltaic group string power cell output voltage in n photovoltaic group string power cell.Due to n photovoltaic group string power unit cascade composition tandem photovoltaic square formation, the output current of its photovoltaic group string power cell is exactly that tandem photovoltaic square formation output current Is is also referred to as direct current system electric current.Direct current system is made up of the direct current importation in tandem photovoltaic square formation, DC equipment or inverter, and direct current system voltage is the nominal DC input voltage of inverter or DC equipment.
Described photovoltaic group string high_voltage isolation power conditioning module is made up of self-supply power source, MPPT photovoltaic group string maximum power point automatic tracking circuit, power conditioning circuitry, communication interface circuit, rectification circuit and high voltage isolating transformer.
The output of photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module.The input of photovoltaic group string high_voltage isolation power conditioning module is connected in parallel by the input of self-supply power source and the input of MPPT photovoltaic group string maximum power point automatic tracking circuit and forms; The output of MPPT photovoltaic group string maximum power point automatic tracking circuit is connected with the input of power conditioning circuitry, the output of power conditioning circuitry is connected with the input of high voltage isolating transformer, the output of high voltage isolating transformer is connected with the input of rectification circuit, the output of rectification circuit is the output of photovoltaic group string high_voltage isolation power conditioning module, also be the output of photovoltaic group string power cell, the power output of photovoltaic group string, finally after high voltage isolating transformer electrical isolation, is exported by rectification circuit direct current.The output of self-supply power source is connected with the input of MPPT photovoltaic group string maximum power point automatic tracking circuit, power conditioning circuitry, communication interface circuit power supply respectively, provides each circuit work power.Namely photovoltaic group string exports an electricity part and provides photovoltaic group string high_voltage isolation power conditioning module power itself needs by self-supply power source, and a large amount of electricity is transported to inverter or DC equipment through MPPT photovoltaic group string maximum power point from the circuit such as motion tracking, equipment by another part.Communication interface circuit is a double-width grinding outputting communication interface circuit, one end of communication interface circuit is connected with power conditioning circuitry communication interface, the other end of communication interface circuit is connected with other photovoltaic group string power cell, inverter or DC equipment by wireless or optical fiber, the control command of inverter or DC equipment and data and each photovoltaic group string power cell is carried out alternately.
When the power output of photovoltaic group string increases with irradiation intensity increase, and when meeting photovoltaic group string high_voltage isolation power conditioning module inner self-supply power source startup power output, self-supply power source stable output voltage provides working power for all circuit, start the work of photovoltaic group string high_voltage isolation power conditioning module, photovoltaic group string high_voltage isolation power conditioning module is by its communication interface and inverter or DC equipment communication.MPPT photovoltaic group string maximum power point automatic tracking circuit carries out MPPT maximum power point tracking to photovoltaic group string in real time simultaneously, and by the maximum power input power regulating circuit of tracked photovoltaic group string, power conditioning circuitry coordinates with high voltage isolating transformer photovoltaic group string maximum power is carried out pwm power adjustment according to photovoltaic group string high_voltage isolation power conditioning module control strategy and inverter or DC equipment order, and the maximum power of the photovoltaic group string after regulating exports through rectification circuit direct current by after high voltage isolating transformer electrical isolation.The electrical isolation voltage > direct current system voltage U smax of high voltage isolating transformer, photovoltaic group string now, due to the electrical isolation of high voltage isolating transformer, makes each photovoltaic group string power cell can bear direct current system voltage U smax.
The data such as output voltage Un, output current Is, maximum power point power, power adjustments power output of photovoltaic group string high_voltage isolation power conditioning module are carried out interactive correspondence by wireless or optical fiber and inverter or DC equipment by the communication interface circuit in described photovoltaic group string high_voltage isolation power conditioning module, otherwise the control command of inverter or DC equipment and data carry out data interaction by this communication interface circuit and each photovoltaic group string power cell.
Described photovoltaic group string is composed in series by n block photovoltaic module.Photovoltaic module is the minimum generator unit of photovoltaic group string, the serial number of photovoltaic module depends primarily on the voltage that photovoltaic module bears, typical case's photovoltaic group string 20 ~ 22 pieces of photovoltaic modulies are composed in series, the photovoltaic group crosstalk pressure-controlled after series connection≤1000V power maximum≤7kWp.
By photovoltaic group string power cell 1, photovoltaic group string power cell 2, photovoltaic group string power cell 3, between the tandem photovoltaic square formation that photovoltaic group string power cell n is composed in series, annexation is: the output negative pole end of photovoltaic group string power cell 1 is connected with the output cathode end of photovoltaic group string power cell 2, the output negative pole end of photovoltaic group string power cell 2 is connected with the output cathode end of photovoltaic group string power cell 3, by that analogy, the output negative pole end of photovoltaic group string power cell n-1 is connected with the output cathode end of photovoltaic group string power cell n, n is positive integer, n>1.The voltage that the voltage that the voltage that the voltage that corresponding photovoltaic group string power cell 1 exports is U1, photovoltaic group string power cell 2 exports is U2, photovoltaic group string power cell 3 exports is U3, photovoltaic group string power cell n exports is Un, all photovoltaic group string power unit cascade electric currents are Is, and series current Is is also tandem photovoltaic square formation output current.The communication interface of photovoltaic group string power cell 1 is connected with the communication interface of photovoltaic group string power cell 2, the like, the communication interface of photovoltaic group string power cell n-1 is connected to the communication interface n of photovoltaic group string power cell n.
The output cathode end of photovoltaic group string power cell 1 is the High voltage output anode of tandem photovoltaic square formation, and the output negative pole end of photovoltaic group string power cell n is the High voltage output negative terminal of tandem photovoltaic square formation.The voltage s that described tandem photovoltaic square formation exports is each photovoltaic group string power cell output voltage sum, i.e. voltage s=voltage 1+ voltage 2+ voltage 3 ... voltage n.The power of photovoltaic group string power cell can not be identical, but output current is identical, and photovoltaic group string power cell series quantity can determine according to electrical network, inverter, distributed area requirements.After n photovoltaic group string power cell serial connection, output voltage values is Us, and be that then Us=10000v is far away higher than parallel photovoltaic group string 1000v for 500v, n=20 as each photovoltaic group string power cell exports average voltage, raising electric pressure, increases power.
Operation principle of the present utility model and the course of work as follows:
For improving photovoltaic arrays power output, employing photovoltaic group string series system is ideal means.But bear voltage <1000v because photovoltaic group string is the highest, as photovoltaic module voltage breakdown caused to damage series connection between photovoltaic group string, between each photovoltaic group string, increase a high_voltage isolation link for this reason, improve the isolation voltage ability of photovoltaic group string.Each photovoltaic group was ganged up after photovoltaic group string high_voltage isolation power conditioning module carries out high-voltage electrical apparatus isolation and was exported by the utility model, make the proof voltage > direct current system voltage U smax of each photovoltaic group string power cell, realize the series connection of n unit photovoltaic group string power cell.
Because the isolation voltage of photovoltaic group string power cell improves, the output voltage of n photovoltaic group string power unit cascade connection is tandem photovoltaic square formation output voltage Us, and tandem photovoltaic square formation output voltage Us is each photovoltaic group string power cell output voltage sum: U1+U2+U3+ ... Un=Us.Because the light group string quantity of the photovoltaic module parameter error in each photovoltaic group string power cell or a certain moment irradiation difference or composition is different, make the optimum output voltage Un of each photovoltaic group string power cell after the adjustment of photovoltaic group string high_voltage isolation power conditioning module likely different, all photovoltaic group string power cell output current Is are equal.If when the power that photovoltaic group string power cell exports can not meet photovoltaic group string high_voltage isolation power conditioning module minimum output power, photovoltaic group string power cell exits output, namely export as short-circuit condition.Photovoltaic group string power cell is as follows with the process prescription of inverter or the work of DC equipment cooperation in different situations:
Under normal irradiation, after each photovoltaic group string power cell starts, first real-time tranception inverter or DC equipment communication data output LOW voltage Unmin, output voltage sum U1min+U2min+U3min+ after n unit photovoltaic group string power unit cascade ... Unmin=Usmin, i.e. tandem photovoltaic square formation minimum output supply power voltage Usmin.
Tandem photovoltaic square formation minimum output supply power voltage Usmin is also inverter or DC equipment direct current starting resistor.When Usmin meets inverter or DC equipment starts operating voltage, each photovoltaic group string power cell has monitored electric current simultaneously and has exported.Photovoltaic group string high_voltage isolation power conditioning module now in each photovoltaic group string power cell calculates photovoltaic group string maximum power point automatically, and by communication interface to inverter or DC equipment transmission photovoltaic group string maximum power point data, after inverter or DC equipment receive data, analyze all photovoltaic group string high_voltage isolation power conditioning module data, and providing each photovoltaic group string power cell optimum voltage value Un and equal output current value Is, each photovoltaic group string power cell is according to this voltage, current value output voltage and electric current.
Increase along with irradiation intensity or reduce, photovoltaic group string power output in each photovoltaic group string power cell synchronously increases or reduces, photovoltaic group string high_voltage isolation power conditioning module simultaneously through this photovoltaic group string power cell detects, and to photovoltaic group string MPPT maximum power point tracking.The photovoltaic group string maximum power point data detected, calculate uploads in inverter or DC equipment through communication interface by photovoltaic group string high_voltage isolation power conditioning module, after inverter or DC equipment receive data, analyze all photovoltaic group string high_voltage isolation power conditioning module data, and providing each photovoltaic group string power cell optimum voltage value Un and identical currents value Is, every photovoltaic group string power cell is according to this voltage, current value output voltage and electric current.
When certain photovoltaic group string is by obnubilation, dust, fault effects power output reduces, or without irradiation, when photovoltaic group string exports as 0v, MPPT photovoltaic group string maximum power point automatic tracking circuit through the photovoltaic group string high_voltage isolation power conditioning module of this photovoltaic group string power cell detects, photovoltaic group string power output can not meet photovoltaic group string high_voltage isolation power conditioning module minimum output power, when maybe cannot meet photovoltaic group string high_voltage isolation power conditioning module self-supply power source starting power, photovoltaic group string high_voltage isolation power conditioning module quits work, high voltage isolating transformer is through rectification circuit VD 0v, output impedance is 0 Ω, be equivalent to output short-circuit, do not affect other photovoltaic group string power cell power outputs in tandem photovoltaic square formation.Now inverter or DC equipment can not receive the data of this photovoltaic power unit, but inverter or DC equipment still can receive the uploading data of other photovoltaic group string power cell that normally works, inverter or DC equipment according to this data analysis calculate to other photovoltaic group string power cells transmission data, provide photovoltaic group string power cell optimum voltage value Un and equal output current value Is, photovoltaic group string power cell is according to this voltage, current value output voltage and electric current.
Inverter or DC equipment orderly closedown under normal irradiation, or surprisingly quit work, or without communication, non-loaded or input disconnect time, the output current Is of the photovoltaic group string high_voltage isolation power conditioning module Real-Time Monitoring inverter in photovoltaic group string power cell or the communication data of DC equipment and photovoltaic group string power cell, when communication data interrupts or output current Is is reduced to the operating current lower limit of inverter or DC equipment, photovoltaic group string high_voltage isolation power conditioning module responds fast, (<20ms) enters default security operating state at short notice, namely micropower pulse voltage <Unmin is exported, Real-Time Monitoring photovoltaic group string power cell output current Is.When monitoring photovoltaic group string power cell output current Is and reaching certain value, illustrate that inverter or DC equipment have accessed and enter startup standby condition, set up communication contact simultaneously, now photovoltaic group string power cell output voltage Unmin.This process is for detecting inverter or whether DC equipment accesses tandem photovoltaic square formation or work.
Due to the starting resistor of photovoltaic group string power cell timing output micropower pulse voltage <Unmin, tandem photovoltaic square formation output voltage after n photovoltaic group string power unit cascade is very low, be less than voltage sum Usmin after n unit photovoltaic group string power unit cascade, and micropower output current is very little, avoid DC high voltage big current very well and draw arc phenomenon, solve the selection issue of high direct voltage General Electric, in other words namely normally or surprisingly quit work at inverter or DC equipment, or without communication, non-loaded or input off-state time, the fast reaction of photovoltaic group string power cell, (<20ms) changes default security operating state at short notice, make the pulse of group string data photovoltaic arrays output LOW voltage micropower, solve high direct voltage General Electric having under loading condition and can be switched on or switched off by low-voltage small area analysis.
Coordinate and manage by inverter or DC equipment because tandem photovoltaic square formation each photovoltaic group string power cell is unified, its photovoltaic group string power can be different, and photovoltaic group string power cell series quantity can according to electrical network, inversion and DC equipment, power station area requirements and determining.Photovoltaic group string exports through photovoltaic group string high_voltage isolation power conditioning module high_voltage isolation thus, the isolation voltage of photovoltaic group string power cell is improved greatly, so n photovoltaic group string power cell serial connection becomes possibility, improve electric pressure, add tandem photovoltaic square formation power.
The utility model has the following advantages:
1, tandem photovoltaic square formation can realize the output of mesohigh direct current, improves photovoltaic array power;
2, high voltage direct current transmission cable loss reduces, and can realize remote Long line transmission;
3, tandem photovoltaic square formation improves due to electric pressure, can realize the transformerless output under this electric pressure, Loss reducing, reduces costs.
4, relatively parallel photovoltaic arrays, tandem photovoltaic square formation can realize the lower voltage of each photovoltaic group string and export startup inverter or DC equipment.
5, in tandem photovoltaic square formation, each photovoltaic group string power cell is unified coordinates and manages by contravariant equipment or DC equipment, possesses best power regulation output, the series connection of different capacity photovoltaic group string power cell can be realized, solve building roof photovoltaic plant because the different installation component power of roof area is inconsistent and fixed object periodically blocking assembly, can not installation component problem, make full use of limited space and realize power station generating and maximize.
6, abandoned converging equipment in tandem photovoltaic square formation and greatly reduced failure rate, power loss and cost, especially the distributed power station of small-power provides simple connected mode.
7, owing to adopting modularization thinking to make convenient engineering installation, use reliably.
Accompanying drawing explanation
Fig. 1 is tandem photovoltaic square formation theory diagram;
Fig. 2 is tandem photovoltaic square formation electricity generation system block diagram;
Fig. 3 is that photovoltaic group string high_voltage isolation power conditioning module internal circuit connects block diagram;
Fig. 4 is the centralized photovoltaic generating system block diagram of prior art;
Fig. 5 is the group string data photovoltaic generating system block diagram of prior art.
Embodiment
The utility model is further illustrated below in conjunction with the drawings and specific embodiments.
The utility model tandem photovoltaic square formation is made up of n photovoltaic group string power unit cascade, is respectively: photovoltaic group string power cell 1, photovoltaic group string power cell 2, photovoltaic group string power cell 3 ... photovoltaic group string power cell n.Photovoltaic group string power cell is composed in series by photovoltaic group string and photovoltaic group string high_voltage isolation power conditioning module.
The output of described photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module, exports through this photovoltaic group string high_voltage isolation power conditioning module DC/DC isolated port.
In photovoltaic group string power cell, output Vzn+, Vzn ﹣ of photovoltaic group string is connected with photovoltaic group string high_voltage isolation power conditioning module input Vin+, Vin-respectively, the power that photovoltaic group string exports exports through this module DC/DC isolation and amplifier port Von+, Von ﹣, and magnitude of voltage is Un.Due to adding of photovoltaic group string high_voltage isolation power conditioning module, make the isolation voltage > Usmax of photovoltaic group string power cell.Each photovoltaic group string high_voltage isolation power conditioning module has a communication interface Tn, described communication interface Tn, and DC/DC isolation and amplifier port Von+, Von ﹣ of this module is also communication interface and the output of photovoltaic group string power cell.Equally, the isolation voltage value of photovoltaic group string high_voltage isolation power conditioning module is also the isolation voltage value of photovoltaic group string power cell.Communication interface Tn can connect optical fiber or wireless communication module.
Described photovoltaic group string high_voltage isolation power conditioning module is made up of self-supply power source, MPPT photovoltaic group string maximum power point automatic tracking circuit, power conditioning circuitry, communication interface circuit, rectification circuit and high voltage isolating transformer.
The output of photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module.As shown in Figure 3, the input of photovoltaic group string high_voltage isolation power conditioning module is composed in parallel by the input of self-supply power source and the input of MPPT photovoltaic group string maximum power point automatic tracking circuit.The output of MPPT photovoltaic group string maximum power point automatic tracking circuit is connected with the input of power conditioning circuitry, the output of power conditioning circuitry is connected with the input of high voltage isolating transformer, the output of high voltage isolating transformer is connected with the input of rectification circuit, the output of rectification circuit is exactly the output of photovoltaic group string high_voltage isolation power conditioning module, also be the output of photovoltaic group string power cell, the power output of photovoltaic group string is finally after high voltage isolating transformer electrical isolation, exported by rectification circuit direct current, realize the DC/DC isolation and amplifier of photovoltaic group string through photovoltaic group string high_voltage isolation power conditioning module.
The output of self-supply power source respectively with MPPT photovoltaic group string maximum power point automatic tracking circuit, power conditioning circuitry, and the input of communication interface circuit power supply connects, and provides each circuit work power.
Communication interface circuit is a double-width grinding outputting communication interface circuit, one end of communication interface circuit is connected with power conditioning circuitry communication interface, the other end is also the communication interface of photovoltaic group string power cell, communication interface circuit is connected with other photovoltaic group string power cell, inverter or DC equipment by wireless or optical fiber, the control command of inverter or DC equipment and data and each photovoltaic group string power cell is carried out alternately.
MPPT photovoltaic group string maximum power point automatic tracking circuit carries out MPPT maximum power point tracking to photovoltaic group string, realizes photovoltaic group string maximum power output.The maximum power output of photovoltaic group string coordinates with high voltage isolating transformer through power conditioning circuitry, carries out pwm power adjustment according to the order of control strategy and inverter or DC equipment, exports through high voltage isolating transformer, rectification circuit direct current.The wherein isolation voltage > Usmax of high voltage isolating transformer, this photovoltaic group string and other photovoltaic group are ganged up high voltage isolating transformer and carries out electrical isolation, so, each photovoltaic group string power cell can be made can to bear direct current system maximum voltage Usmax.Pwm power adjustment in photovoltaic group string high_voltage isolation power conditioning module, output voltage Un, output current Is carry out communication by communication interface circuit through wireless or optical fiber and other photovoltaic group string power cell, inverter or DC equipment, complete inverter or DC equipment intercoms mutually with tandem photovoltaic square formation.
Described direct current system maximum voltage Usmax=U1max+U2max+U3max ... + Unmax, U1max, U2max ... the maximum that Unmax is photovoltaic group string power cell 1, photovoltaic group string power cell 2 arrives each photovoltaic group string power cell output voltage of photovoltaic group string power cell n, and every block photovoltaic group string high_voltage isolation power conditioning module isolation voltage > Usmax.
Described photovoltaic group string is composed in series by some pieces of photovoltaic modulies, and the output port of photovoltaic group string is Vzn+, Vzn-.Described photovoltaic module is the minimum generator unit of photovoltaic group string, serial number depends primarily on the voltage that photovoltaic module bears, typical photovoltaic group string adopts 20 ~ 22 pieces of photovoltaic modulies to be composed in series, the group crosstalk pressure-controlled after photovoltaic module series connection≤1000V power maximum≤7kWp.
The output negative terminal Vo1 ﹣ of photovoltaic group string power cell 1 is connected with photovoltaic group string power cell 2 output plus terminal Vo2+, the output negative terminal Vo2 ﹣ of photovoltaic group string power cell 2 is connected with the output plus terminal Vo3+ of photovoltaic group string power cell 3, by that analogy, the output negative terminal Von-1 ﹣ of photovoltaic group string power cell n-1 is connected with the output plus terminal Von+ of photovoltaic group string power cell n, n is positive integer, n>1.
The output voltage of photovoltaic group string power cell 1 is U1, the output voltage of photovoltaic group string power cell 2 is U2, the output voltage of photovoltaic group string power cell 3 be U3 ..., the output voltage of photovoltaic group string power cell n is Un.Tandem photovoltaic square formation output current is Is, also referred to as system works electric current.
The communication interface T1 of photovoltaic group string power cell 1 is connected with the communication interface T2 of photovoltaic group string power cell 2, the like.The communication interface Tn-1 of photovoltaic group string power cell n-1 is connected to the communication interface Tn of photovoltaic group string power cell n.The output Vo1+ of photovoltaic group string power cell 1 is the High voltage output+end of tandem photovoltaic square formation, the output Von ﹣ of photovoltaic group string power cell n is the High voltage output-end of tandem photovoltaic square formation, its High voltage output+, High voltage output-output voltage values is Us, Us=U1+U2+U3 ... Un.Photovoltaic group string power unit cascade quantity can according to electrical network, inverter, distributed area requirements.Tandem photovoltaic square formation output voltage values through multiple photovoltaic group string power cell serial connection is Us, if each photovoltaic group string power cell output average voltage is 500v, n=20 then Us=10000v, far away higher than parallel photovoltaic group string 1000v, improves electric pressure, adds power.
Figure 2 shows that the structure of the utility model tandem photovoltaic square formation.Multiple photovoltaic module composition photovoltaic group string, the output correspondence often organizing photovoltaic group string connects a photovoltaic group string high_voltage isolation power conditioning module.Photovoltaic group string and photovoltaic group string high_voltage isolation power conditioning module are composed in series photovoltaic group string power cell.Photovoltaic group string 1 ..., photovoltaic group string n correspondence connects photovoltaic group string high_voltage isolation power conditioning module 1 ..., photovoltaic group string high_voltage isolation power conditioning module n, carries out group string high_voltage isolation power adjustments through photovoltaic group string high_voltage isolation power conditioning module and exports.The positive pole of photovoltaic group string high_voltage isolation power conditioning module 1 is connected with the input anode of inverter or DC equipment, the negative pole of photovoltaic group string high_voltage isolation power conditioning module n is connected with the input negative terminal of inverter or DC equipment, composition+, ﹣ positive and negative DC series formula photovoltaic arrays.
Compared with the group serial type photovoltaic generating system shown in the concentrated photovoltaic generating system shown in Fig. 4, Fig. 5, the advantage of the utility model tandem photovoltaic square formation is:
1, converging equipment is not had in the tandem photovoltaic square formation shown in Fig. 2, header box, DC cabinet in concentrated photovoltaic generating system shown in Fig. 4, interchange cabinet in group serial type photovoltaic generating system shown in Fig. 5 all belongs to converging equipment, the quantity of power difference configuration is different, and in photovoltaic system, converging equipment breaks down, and rate is high, loss is large.The utility model tandem photovoltaic square formation has abandoned a large amount of converging equipment, reduces the wastage, reduces cost, improves reliability;
2, in the tandem photovoltaic square formation shown in Fig. 2, photovoltaic group string is connected with photovoltaic group string high_voltage isolation power conditioning module nearby, all be connected in series by unit cable between the photovoltaic group string high_voltage isolation power conditioning module of Fig. 2, output current is a string photovoltaic group crosstalk stream (current photovoltaic group string maximum short circuit current < 10A).And Fig. 4, in system shown in Fig. 5, converging equipment installation site must be taken into account many group photovoltaic group strings and lay layout, cause n multiple-twin cable in parallel in converging equipment to converging equipment installation site, (as 16 road header boxs complete 16 road photovoltaic group connection in series-parallel, number of cables is 16 × 2, its electric current that confluxes is 16 × 10A=160A, n platform group string inverter exchanges and exports an ac cable parallel connection through n × 4, the after-current that confluxes increases n doubly, and converging equipment is in parallel in 2 direct currents or 4 AC great current cables to upper level converging equipment or inverter again, compare the tandem photovoltaic square formation shown in Fig. 2, number of cables increases greatly, and electric current is large, loss, cost increases,
3, tandem photovoltaic square formation shown in Fig. 2, photovoltaic group string improves inverter or DC equipment input direct voltage by the series connection between photovoltaic group string high_voltage isolation power conditioning module, if each photovoltaic group string power cell output average voltage is 500v, 20 photovoltaic group string power cells, then inversion, DC equipment input voltage Us=20 × 500v=10000v can far above Fig. 4, inverter input voltage <1000v shown in Fig. 5, under Same Efficieney condition, make cascaded structure electric current reduce, change parallel heavy-current transmission current mode, reduce the power loss of cable and equipment, and promote photovoltaic arrays power,
4, in the tandem photovoltaic square formation shown in Fig. 2, photovoltaic group was ganged up series connection between photovoltaic group string high_voltage isolation power conditioning module and was improved inverter or DC equipment input direct voltage, can realize lower than input direct voltage/
the grid-connected output of transless, and the photovoltaic generating system shown in Fig. 4, Fig. 5, due to the restriction of inverter input direct voltage < 1000v, inverter ac output voltage≤400v system transless can only be met grid-connected, more grid-connected then must the conversion through high-tension transformer of high voltage exports, and electric current is large, loss is large, cost is high;
5, the tandem photovoltaic square formation in Fig. 2 is that positive and negative 2 line direct currents export, organizing two direct current cabless adopt with the centralized photovoltaic generating system of Fig. 4 under its equal power output condition in parallel more, group string data photovoltaic generating system shown in Fig. 5 adopts many groups 3 phase 4 line ac cable output-parallels to compare, cable greatly reduces, and electric current is little, reduce cable loss.The square array structure of tandem photovoltaic shown in Fig. 2+, ﹣ direct current export, add the serial number of photovoltaic group string, improve direct current supply power;
6, in the tandem photovoltaic square formation shown in Fig. 2, it is flexible that photovoltaic group ganged up photovoltaic group string high_voltage isolation power conditioning module output voltage, the series connection of photovoltaic group string under more low-voltage condition between photovoltaic group string high_voltage isolation power conditioning module can be made to improve output dc voltage, meet inversion, DC equipment starting resistor.And the photovoltaic generating system shown in Fig. 4, because the parallel-connection structure of photovoltaic group string limit, every optical crosstalk volt group connection in series-parallel output voltage is improved according to grid-connected voltage, the input starting resistor primary condition of inverter could be met, as in 380v ac grid system, photovoltaic group string output dc voltage > 400v ×
more than could meet and start inverter work primary condition.
7, inverter or DC equipment are divided into current mode or voltage-type in power electronic equipment topological structure, its feature: voltage-type voltage high current is little, and loss is little, and current mode voltage low current is large, and loss is large.Tandem photovoltaic square formation shown in Fig. 2 adopts cascaded structure, inverter or DC equipment input current little, make every block adjustment module autophage power little of fanning heat treatment.Same employing tandem photovoltaic square formation, inverter or DC equipment input voltage height electric current little, should adopt voltage-type topological structure inverter or DC equipment power consumption little.And the photovoltaic generating system shown in Fig. 4 is due to photovoltaic group string employing parallel-connection structure, output voltage < 1000v, electric current is large, adopt current mode topological structure inverter, compare the voltage-type inversion in the tandem photovoltaic square formation of Fig. 2, DC equipment, power loss is large, and efficiency is low.
Claims (3)
1. a tandem photovoltaic square formation, is characterized in that, described photovoltaic arrays is made up of n photovoltaic group string power unit cascade, n > 1; Photovoltaic group string power cell is composed in series by photovoltaic group string and photovoltaic group string high_voltage isolation power conditioning module; The output of described photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module, exports through this photovoltaic group string high_voltage isolation power conditioning module DC/DC isolated port.
2. according to tandem photovoltaic square formation according to claim 1, it is characterized in that, described photovoltaic group string high_voltage isolation power conditioning module is made up of self-supply power source, MPPT photovoltaic group string maximum power point automatic tracking circuit, power conditioning circuitry, communication interface circuit, rectification circuit and high voltage isolating transformer;
The output of photovoltaic group string is connected with the input of photovoltaic group string high_voltage isolation power conditioning module; The input of photovoltaic group string high_voltage isolation power conditioning module is connected in parallel by the input of self-supply power source and the input of MPPT photovoltaic group string maximum power point automatic tracking circuit and forms; The output of MPPT photovoltaic group string maximum power point automatic tracking circuit is connected with the input of power conditioning circuitry, the output of power conditioning circuitry is connected with the input of high voltage isolating transformer, the output of high voltage isolating transformer is connected with the input of rectification circuit, the output of rectification circuit is the output of photovoltaic group string high_voltage isolation power conditioning module, is also the output of photovoltaic group string power cell; The power output of photovoltaic group string, finally after high voltage isolating transformer electrical isolation, is exported by rectification circuit direct current; The output of self-supply power source respectively with MPPT photovoltaic group string maximum power point automatic tracking circuit, power conditioning circuitry, and the input of communication interface circuit power supply connects, and provides each circuit work power;
Communication interface circuit is a double-width grinding outputting communication interface circuit, one end of communication interface circuit is connected with power conditioning circuitry communication interface, the other end of communication interface circuit is connected with other photovoltaic group string power cell, inverter or DC equipment by wireless or optical fiber, the control command of inverter or DC equipment and data and each photovoltaic group string power cell is carried out alternately.
3. according to tandem photovoltaic array according to claim 1, it is characterized in that, each described photovoltaic group was ganged up after photovoltaic group string high_voltage isolation power conditioning module carries out high-voltage electrical apparatus isolation and was exported, and made the proof voltage > direct current system voltage U smax of each photovoltaic group string power cell.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104113280A (en) * | 2014-07-05 | 2014-10-22 | 北京科诺伟业科技股份有限公司 | Serial-connection-type photovoltaic square matrix |
| EP3373433B1 (en) * | 2017-03-07 | 2020-04-29 | ABB Schweiz AG | A photovoltaic power plant system |
| CN111641209A (en) * | 2020-06-13 | 2020-09-08 | 深圳市鹏城新能源科技有限公司 | Distributed photovoltaic module working mode switching method and system based on 5G communication |
-
2014
- 2014-07-05 CN CN201420370653.4U patent/CN204103855U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104113280A (en) * | 2014-07-05 | 2014-10-22 | 北京科诺伟业科技股份有限公司 | Serial-connection-type photovoltaic square matrix |
| EP3373433B1 (en) * | 2017-03-07 | 2020-04-29 | ABB Schweiz AG | A photovoltaic power plant system |
| CN111641209A (en) * | 2020-06-13 | 2020-09-08 | 深圳市鹏城新能源科技有限公司 | Distributed photovoltaic module working mode switching method and system based on 5G communication |
| CN111641209B (en) * | 2020-06-13 | 2021-03-16 | 深圳市鹏城新能源科技有限公司 | Distributed photovoltaic module working mode switching method and system based on 5G communication |
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