CN108565891A - A kind of photovoltaic string formation cutoff device, method and photovoltaic system - Google Patents
A kind of photovoltaic string formation cutoff device, method and photovoltaic system Download PDFInfo
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- CN108565891A CN108565891A CN201810386211.1A CN201810386211A CN108565891A CN 108565891 A CN108565891 A CN 108565891A CN 201810386211 A CN201810386211 A CN 201810386211A CN 108565891 A CN108565891 A CN 108565891A
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- H02J3/385—
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses a kind of photovoltaic string formation cutoff devices, including switching device, harvester and shutdown controller.Shutdown controller is when judging that the run signal of harvester acquisition meets default turn-off criterion, triggering MPPT unit enters string formation shutdown mode by current maximal power tracing pattern, so that each photovoltaic string formation increases to open-circuit voltage by the corresponding voltage of maximum power, the target switch device turned off when reaching open-circuit voltage on the circuit that controller control is abnormal disconnects.When reaching open-circuit voltage, the electric current of photovoltaic string formation output levels off to zero, and the requirement for switching device is relatively low, can reliably disconnect；In addition, after target switch device disconnects, then the input current of inversion unit DC side, voltage and power are just very small, it is not easy to which phenomena such as leading to overheat, leak electricity, direct current cutoff device being capable of reliable turn-off.In addition, invention additionally discloses a kind of photovoltaic string formation cut-off method and photovoltaic system, effect are as above.
Description
Technical field
The present invention relates to technical field of photovoltaic power generation, more particularly to a kind of photovoltaic string formation cutoff device, method and photovoltaic
System.
Background technology
Photovoltaic system is widely used general at present, especially the popularization of distributed photovoltaic system.Although the hair of photovoltaic system
Exhibition can promote the better utilization of regenerative resource, but photovoltaic system also brought some problems in recent years, for example, photovoltaic
Fire incident has gradually threatened the safety of residential housing, commercial facility, communal facility and its photovoltaic system.Photovoltaic system includes
Photovoltaic string formation, the MPPT unit being connect with photovoltaic string formation (MPPT, i.e. MPPT maximum power point tracking), inversion unit, DC side shutdown
The components such as device.Wherein, MPPT unit be mainly used for control photovoltaic string formation be operated in maximum power point, MPPT unit mainly controls
Each photovoltaic string formation is operated in maximum power pattern, and it is defeated that inversion unit is mainly used for the direct current for generating photovoltaic string formation progress inversion
Go out, DC side cutoff device is used in the DC side of inversion unit, and the input for cutting off inversion unit, therefore, DC side turn off
The reliability and stability of device are directly related to the stable electric generation and income of photovoltaic system, directly influence the peace of photovoltaic system
Full reliability service.
In the prior art, the DC side cutoff device used in inversion unit DC side is mostly using alternating-current switch or its improvement
Therefore product is not the DC switchgear cut off with safe arc extinguishing, high power really applied in photovoltaic system.
The arc extinguishing ability of these switches, normal band load rupturing duty are all far from enough, therefore, are easy to cause overheat, electric leakage and spark, sternly
Even burn entire photovoltaic plant when weight.Simultaneously as photovoltaic system DC voltage grade is gradually promoted to 1500V, single machine
Power grade increases, and inversion unit is stringenter to stress levels and the breaking capacity requirement of DC side cutoff device, and city
There may be design defect to cause switch that can not completely cut through for DC side cutoff device on field, or even generates phenomenon of arc discharge, generates
Huge heat become photovoltaic system electrical fire hidden danger.
In conclusion how to ensure that the reliable turn-off of DC side cutoff device is that those skilled in the art are urgently to be resolved hurrily and asks
Topic.
Invention content
The object of the present invention is to provide a kind of photovoltaic string formation cutoff device, method and photovoltaic systems, for ensureing DC side
The reliable turn-off of cutoff device.
In order to solve the above technical problems, the present invention provides a kind of photovoltaic string formation cutoff device, including it is arranged in each photovoltaic group
Switching device on string loop, the harvester of the run signal for acquiring each photovoltaic group string loop and the acquisition
The shutdown controller that device is connected with MPPT unit；The shutdown controller is used to meet default shutdown item in the run signal
When part, triggers the MPPT unit and string formation shutdown mode is entered so that the MPPT unit by current maximal power tracing pattern
It controls each photovoltaic group string loop and open-circuit voltage is increased to by the corresponding voltage of maximum power, and reaching the open-circuit voltage
When control target switch device disconnect.
Preferably, the shutdown controller specifically includes the A/D conversion equipments being connect with the harvester and the A/
The signal regulating device of D conversion equipments connection, the MCU being connect with the signal regulating device.
Preferably, the switching device is specially relay, and the contact setting of the relay is returned in the photovoltaic string formation
On the road, the coil of the relay is connect with the shutdown controller.
Preferably, further include the diode being arranged on each photovoltaic group string loop, the anode of the diode and institute
The connection of photovoltaic string formation is stated, the cathode of the diode is connect with the MPPT unit.
Preferably, the shutdown controller is additionally operable to trigger the MPPT unit when receiving external shutdown control instruction
Into the string formation shutdown mode.
Preferably, the shutdown controller is additionally operable to after disconnecting the target switch device, triggers the MPPT unit
Into the maximal power tracing pattern.
Preferably, the harvester is specially current sensor, voltage sensor, temperature sensor, corresponding described
Run signal is specially the electric current of the photovoltaic group string loop, the voltage of the photovoltaic group string loop, the photovoltaic group string loop
Temperature.
In order to solve the above technical problems, the present invention also provides a kind of photovoltaic string formation cut-off methods, including：
Acquire the run signal of each photovoltaic group string loop；
The run signal is obtained, and when the run signal meets and presets turn-off criterion, triggering MPPT unit is by working as
Preceding maximal power tracing pattern enter string formation shutdown mode so that the MPPT unit control each photovoltaic group string loop by
The corresponding voltage of maximum power increases to open-circuit voltage, and is set in target photovoltaic string formation reaching the open-circuit voltage time control and setting up
Switching device on circuit disconnects.
Preferably, after determining that the run signal is unsatisfactory for default turn-off criterion, further include：
Judge whether to receive external shutdown control instruction；
If it is, triggering the MPPT unit enters the string formation shutdown mode.
In order to solve the above technical problems, the present invention provides also a kind of photovoltaic system, including photovoltaic string formation described above is closed
Disconnected device.
Photovoltaic string formation cutoff device provided by the invention, including switching device, harvester and shutdown controller, wherein
Switching device is arranged on each photovoltaic group string loop, and is switched on and off by the control realization of shutdown controller, and harvester is adopted
Collect the run signal on each photovoltaic group string loop, then transmit the signal to shutdown controller, shutdown controller utilizes predetermined
Algorithm judge whether run signal exception occurs, i.e., whether meet default turn-off criterion, if it is, illustrating the run signal
There is exception in the circuit at place, then turns off controller and trigger MPPT unit connected to it by current maximal power tracing pattern
Into string formation shutdown mode, then MPPT unit controls each photovoltaic string formation and increases to open-circuit voltage by the corresponding voltage of maximum power,
The target switch device turned off when reaching open-circuit voltage on the circuit that controller control is abnormal disconnects.It will be apparent that when reaching
When to open-circuit voltage, the electric current of photovoltaic string formation output levels off to zero, and therefore, the requirement for switching device is relatively low, can be reliable
It disconnects；In addition, after target switch device disconnects, then the input current of inversion unit DC side, voltage and power are just very small,
Phenomena such as not easily leading to overheat, electric leakage, direct current cutoff device being capable of reliable turn-off.In conclusion the present apparatus can reduce pair
The requirement of direct current cutoff device improves the reliable turn-off of inversion unit DC side, prevents photovoltaic system from electrical fire etc. occurs hidden
Suffer from.
Description of the drawings
In order to illustrate the embodiments of the present invention more clearly, attached drawing needed in the embodiment will be done simply below
It introduces, it should be apparent that, drawings in the following description are only some embodiments of the invention, for ordinary skill people
For member, without creative efforts, other drawings may also be obtained based on these drawings.
Fig. 1 is a kind of structure chart of photovoltaic string formation cutoff device provided in an embodiment of the present invention；
Fig. 2 is a kind of structure chart of photovoltaic system provided in an embodiment of the present invention；
Fig. 3 is a kind of voltage and current change schematic diagram of photovoltaic group string loop provided by the invention；
Fig. 4 is a kind of corresponding flow chart of active shutdown mode provided in an embodiment of the present invention；
Fig. 5 is a kind of corresponding flow chart of passive shutdown mode provided in an embodiment of the present invention；
Fig. 6 is a kind of flow chart of photovoltaic string formation cut-off method provided in an embodiment of the present invention.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, rather than whole embodiments.Based on this
Embodiment in invention, without making creative work, what is obtained is every other by those of ordinary skill in the art
Embodiment belongs to the scope of the present invention.
Core of the invention is to provide a kind of photovoltaic string formation cutoff device, method and photovoltaic system, the wherein mesh of the device
Be improve DC side cutoff device reliable turn-off.
In order to enable those skilled in the art to better understand the solution of the present invention, with reference to the accompanying drawings and detailed description
The present invention is described in further detail.
Embodiment one
Fig. 1 is a kind of structure chart of photovoltaic string formation cutoff device provided in an embodiment of the present invention.As shown in Figure 1, the device
The acquisition of switching device 10 including being arranged on each photovoltaic group string loop, run signal for acquiring each photovoltaic group string loop
Device 11, the shutdown controller 13 being connect with harvester 11 and MPPT unit 12；Controller 13 is turned off to be used in run signal
Meet when presetting turn-off criterion, triggering MPPT unit 12 string formation shutdown mode entered by current maximal power tracing pattern so that
MPPT unit 12 controls each photovoltaic group string loop and increases to open-circuit voltage by the corresponding voltage of maximum power, and is reaching open circuit electricity
Target switch device is controlled when pressure to disconnect.
The invention aims to improve the reliable turn-off of DC side cutoff device, it is based on this purpose, the approach one of solution
Aspect is improved DC side cutoff device itself, is on the other hand the requirement reduced to DC side cutoff device, the present invention
The scheme provided is exactly the latter.
Fig. 2 is a kind of structure chart of photovoltaic system provided in an embodiment of the present invention.It should be noted that under normal conditions,
Can include multiple photovoltaic group string loops, PV1-PVN in photovoltaic system.Each photovoltaic group string loop corresponds to one group of switching device
(can be a switching device can also be multiple) and one group of harvester (can be a type of sensor, it can also
For a plurality of types of sensors), be mutual indepedent between switching device, the break-make in circuit where can only realizing, harvester it
Between be also mutual indepedent, the run signal in circuit where can only acquiring.
In specific implementation, the operating mode of MPPT unit is divided into maximal power tracing pattern and string formation shutdown mode, this
The control of both of which is the control signal deciding by shutdown controller.Fig. 3 is that a kind of photovoltaic string formation provided by the invention is returned
The voltage and current change schematic diagram on road.Wherein, abscissa indicates that voltage value, ordinate indicate current value.When I-V curve operating point
It is maximal power tracing mode when positioned at maximum power point MPP；It is then string formation when the voltage of I-V curve operating point is located at Uoc
Lockout mode.It is switched over by string formation operating voltage active accommodation between both patterns.Under normal circumstances, controller is turned off
The control signal of maximal power tracing pattern is transmitted into MPPT unit, at this point, MPPT unit will according to maximum power with
The voltage of each photovoltaic string formation of track scheme control operates in the corresponding voltage of maximum power point, in such a mode, each photovoltaic string formation
The voltage in circuit is in the corresponding voltage U of maximum power pointMPP, the voltage is usually larger, such as is 800V in Fig. 3, inverse at this time
The voltage that the DC side cutoff device of the DC side of change unit is born is also into 800V, if there is exception in photovoltaic group string loop,
Then DC side cutoff device just needs in the case of 800V voltages, to cut off the input of inversion unit, it is obvious that this is for direct current
The requirement of cutoff device is with regard to very high, once DC side cutoff device is unsatisfactory for requiring, it is easy to and cause photovoltaic system that fire occurs
The accidents such as calamity.Based on this, in the present embodiment, the shutdown advance programming of controller has the decision logic of run signal, i.e. which kind of type
Run signal should meet which kind of requirement, once being unsatisfactory for, then illustrate that the photovoltaic group string loop corresponding to the run signal is different
Often, shutdown controller according to this judging result can trigger MPPT unit by current maximal power tracing pattern enter string formation close
Disconnected pattern.At this point, MPPT unit powers on pressure according to the corresponding photovoltaic group string loop of preset algorithm adjusting rises to open-circuit voltage UOC,
So that the output current of photovoltaic group string loop levels off to zero, in this case, shutdown controller is opened by connected to it again
It is disconnected to close device (i.e. target switch device, target switch device are switching devices corresponding with the photovoltaic group string loop being abnormal)
It opens so that corresponding photovoltaic string formation loop open circuit.After target switch device disconnects, then the input of inversion unit DC side is electric
Stream, voltage and power are just very small, it is not easy to which phenomena such as leading to overheat, leak electricity, direct current cutoff device being capable of reliable turn-off.
In order to allow the corresponding photovoltaic group string loop of adjusting that those skilled in the art more understand that the present invention is previously mentioned to power on
Pressure rises to open-circuit voltage UOCDetailed process, the present embodiment will be explained in.It is lifting system operating voltage U firstOP, i.e. work
Make voltage UOPFrom maximum power voltage UMPPStart cumulative fixed step size voltage lifting system operating voltage △ U, every time after adjustment
Operating voltage is UOP=UOP+△U；It is carried out at the same time maximum working voltage optimizing UOP≥Max[UOP,UMPP], it is in combination with electric current
No minimum judges operating voltage UOPWhether stablize in voltage max, i.e., whether reaches open-circuit voltage Uoc.Open-circuit voltage pattern
Adjustment result be string formation operating current IOPReach cut-off current minimum limit value Iref, the switching device in the i-th circuit can be cut.
Then the software delay △ T for carrying out the short time, ensure that the action of switching device is properly completed.
It should be noted that the default turn-off criterion described in this implementation can be according to the run signal that harvester acquires
Type determines condition itself, such as run signal is current signal, then presetting turn-off criterion can be for one about current value
Range has been more than this range (over-current detection), then it is assumed that is abnormal, that is, meets and preset turn-off criterion.Other types of operation
Signal is same as above, and is no longer repeated one by one.Preferably embodiment, harvester be specially current sensor, voltage sensor,
Temperature sensor, corresponding run signal are specially the electric current of photovoltaic group string loop, the voltage of photovoltaic group string loop, photovoltaic string formation
The temperature in circuit.It is understood that there are many types of run signal, above-mentioned preferred embodiment is only therein three
Kind, it does not represent and there was only these three signals.
In addition, the corresponding electric topology circuit of MPPT unit, in level-one inversion topological, predominantly single-phase or three-phase H bridges
Formula inverter circuit；In two-stage inversion topological, predominantly DC/DC booster circuits, DC/AC inverter circuits.
String formation cutoff device application scenarios provided by the present invention do not limit, such as can be applied to string type inversion list
It is inverse to be equally applicable to centralization for the MPPT unit of member or the prime BOOST boost types of collecting and distributing type inversion unit prime header box
Become the MPPT unit of the three-phase H bridge type inversion type of unit.
Photovoltaic string formation cutoff device provided in this embodiment, including switching device, harvester and shutdown controller,
In, switching device is arranged on each photovoltaic group string loop, and is switched on and off by the control realization of shutdown controller, harvester
The run signal on each photovoltaic group string loop is acquired, then transmits the signal to shutdown controller, shutdown controller is using in advance
Fixed algorithm judges whether run signal exception occurs, i.e., whether meets default turn-off criterion, if it is, illustrating that the operation is believed
There is exception in circuit where number, then turns off controller and trigger MPPT unit connected to it by current maximal power tracing mould
Formula enters string formation shutdown mode, then MPPT unit controls each photovoltaic string formation and increases to open circuit electricity by the corresponding voltage of maximum power
Pressure, the target switch device turned off when reaching open-circuit voltage on the circuit that controller control is abnormal disconnect.It will be apparent that working as
When reaching open-circuit voltage, the electric current of photovoltaic string formation output levels off to zero, be equivalent to it is even unloaded in load shedding, therefore, for switch
The requirement of device is relatively low, can reliably disconnect；In addition, after target switch device disconnects, then the input of inversion unit DC side
Electric current, voltage and power are just very small, it is not easy to which phenomena such as leading to overheat, leak electricity, direct current cutoff device being capable of reliable turn-off.It is comprehensive
Upper described, the present apparatus can reduce the requirement to direct current cutoff device, improve the reliable turn-off of inversion unit DC side, prevent light
The hidden danger such as electrical fire occur for volt system.
Preferably embodiment, shutdown controller specifically include the A/D conversion equipments and A/ being connect with harvester
The signal regulating device of D conversion equipments connection, the MCU being connect with signal regulating device.
Under normal conditions, the run signal of harvester acquisition is analog signal, and analog signal will carry out subsequent patrol
It collects and judges, need to be converted to digital signal, the model of the A/D conversion equipments in present embodiment can be true according to actual conditions
Fixed, this embodiment is not repeated.Signal regulating device is used to carry out signal condition to the signal received, wherein including signal
Amplification, the operations such as filtering.MCU is the core devices for executing logic judgment, and microcontroller etc., the present embodiment can be selected no longer superfluous
It states.
Preferably embodiment, switching device are specially relay, and the contact setting of relay is returned in photovoltaic string formation
On the road, the coil of relay is connect with shutdown controller.
Relay is usually applied in automation control circuit, it is actually to go control high current running with low current
One kind " automatic switch ".Therefore the effects that playing automatic adjustment, safeguard protection, conversion circuit in circuit.It should be noted that
Switching device can also be that contactor or other types of switch, the present embodiment are not construed as limiting other than relay.
Embodiment two
As shown in Fig. 2, on the basis of embodiment one, preferably embodiment, further includes being arranged in each photovoltaic group
The anode of diode D on string loop, diode D are connect with photovoltaic string formation, and the cathode of diode is connect with MPPT unit 12.
In the present embodiment, diode action is mainly reverse isolation, due between different string formations PV+ and PV- in MPPT
Confluence in unit, after a certain string formation direct current is cut off, the high voltage at the contact both ends of switching device still remains certain peace
Full hidden danger；Diode can prevent other string formations or MPPT unit rear class to the string formation current flowing backwards.It can by the way that diode is arranged
To effectively prevent electric current reversely to be damaged to photovoltaic string formation, the parameter of diode is needed according to specific photovoltaic group string loop
Depending on actual parameter, the present embodiment is not construed as limiting.
Embodiment three
In above-described embodiment, shutdown controller is the logic judgment carried out according to the run signal of photovoltaic group string loop, from
And it controls MPPT unit and is in maximal power tracing pattern or string formation shutdown mode.In specific implementation, in addition to run signal is different
Often causing MPPT unit to enter, string formation shutdown mode is outer (active shutdown mode), and shutdown controller is additionally operable to receiving outside
Triggering MPPT unit enters string formation shutdown mode (passive shutdown mode) when turning off control instruction.
Mainly overcurrent, leakage current, the excessively high automatic drop of overvoltage, inversion unit temperature are occurring for active shutdown mode
When load, arc fault and fire conditions, a kind of protectiveness shutdown that string formation cutoff device is made acts.
Fig. 4 is a kind of corresponding flow chart of active shutdown mode provided in an embodiment of the present invention.Such as Fig. 4, shutdown item is preset
Part is 5 sub- conditions, including the following steps.
S40：Photovoltaic group string loop whether overcurrent；
S41：Photovoltaic group string loop whether overvoltage；
S42：Photovoltaic group string loop whether leakage current；
S43：Inversion unit whether excess temperature；
S44：Photovoltaic string formation whether there is arc fault.
If above-mentioned several conditions are all no, the judgement of this sub-subroutine terminates, otherwise, as long as there are one the judgements of condition
As a result it is yes, then enters step S45；
S45：Corresponding photovoltaic group string loop is actively turned off into mark position 1.
It is then powered off controller triggering MPPT unit and enters string formation shutdown mode.
Passive shutdown mode mainly power station inspection, module testing, safeguard when artificial input shutdown control instruction, or
Receive the shutdown control instruction that higher level's measure and control device issues.Fig. 5 is a kind of passive shutdown mode pair provided in an embodiment of the present invention
The flow chart answered.Outside shutdown control instruction, which specifically includes, is manually entered the shutdown instruction that shutdown instruction is issued with higher level, such as schemes
5, include the following steps：
S50：Whether shutdown instruction is manually entered；
S51：Whether shutdown instruction that higher level issue is had.
If above-mentioned several conditions are all no, the judgement of this sub-subroutine terminates, otherwise, as long as there are one the judgements of condition
As a result it is yes, then enters step S52；
S52：By the passive shutdown mark position 1 of corresponding photovoltaic group string loop.
Example IV
In the above-described embodiments, MPPT unit is made to enter string formation shutdown mould if some photovoltaic group string loop is abnormal
After formula, the corresponding target switch device in the road can be disconnected.At this point, other photovoltaic group string loops are still normal condition, therefore close
Disconnected controller is additionally operable to after disconnecting target switch device, and triggering MPPT unit enters maximal power tracing pattern.
In the present embodiment, remaining photovoltaic group string loop in photovoltaic system can be again controlled after occurring extremely
Into normal operating conditions, photovoltaic system long-time fallback is avoided.
Embodiment five
The various embodiments described above are to be directed to photovoltaic string formation cut-off method, and the present invention also provides a kind of photovoltaic string formation cut-off methods pair
The embodiment answered.Fig. 6 is a kind of flow chart of photovoltaic string formation cut-off method provided in an embodiment of the present invention.As shown in fig. 6, the party
Method includes：
S60：Acquire the run signal of each photovoltaic group string loop；
S61：Run signal is obtained, and when run signal meets and presets turn-off criterion, triggering MPPT unit is by current
Maximal power tracing pattern enters string formation shutdown mode so that MPPT unit controls each photovoltaic group string loop and corresponded to by maximum power
Voltage increase to open-circuit voltage, and set up the switching device set on target photovoltaic string formation circuit reaching open-circuit voltage time control
It disconnects.
Preferably embodiment further includes after determining that run signal is unsatisfactory for default turn-off criterion：
Judge whether to receive external shutdown control instruction；
If it is, triggering MPPT unit enters string formation shutdown mode.
Since the embodiment of device part is corresponded with the embodiment of method part, because the embodiment of the method part is asked
Referring to the description of the embodiment of device part, wouldn't repeat here.
Photovoltaic string formation cut-off method provided in this embodiment, can to harvester acquire run signal judge,
When judging that run signal meets default turn-off criterion, triggering MPPT unit increases to open circuit by the corresponding voltage of maximum power
Voltage, and set up the switching device disconnection set on target photovoltaic string formation circuit reaching open-circuit voltage time control.It will be apparent that when reaching
When to open-circuit voltage, the electric current of photovoltaic string formation output levels off to zero, be equivalent to it is even unloaded in load shedding, therefore, for derailing switch
The requirement of part is relatively low, can reliably disconnect；In addition, after target switch device disconnects, then the input of inversion unit DC side is electric
Stream, voltage and power are just very small, it is not easy to which phenomena such as leading to overheat, leak electricity, direct current cutoff device being capable of reliable turn-off.To sum up
Described, this method can reduce the requirement to direct current cutoff device, improve the reliable turn-off of inversion unit DC side, prevent photovoltaic
The hidden danger such as electrical fire occur for system.
Embodiment six
The embodiment of the present invention also provides a kind of photovoltaic system, it is to be understood that photovoltaic system includes inversion unit, photovoltaic
String formation, the components such as direct current cutoff device further include the photovoltaic string formation cutoff device described in above-described embodiment.Specific photovoltaic string formation is closed
The structure of disconnected device refers to described above, and this embodiment is not repeated.
Photovoltaic system provided in this embodiment further includes the shutdown of photovoltaic string formation in addition to the component that photovoltaic system itself includes
Device, the device include switching device, harvester and shutdown controller, wherein switching device setting is returned in each photovoltaic string formation
On the road, and by the control realization of shutdown controller it switches on and off, harvester acquires the letter of the operation on each photovoltaic group string loop
Number, shutdown controller is then transmitted the signal to, shutdown controller judges whether run signal occurs using scheduled algorithm
It is abnormal, i.e., whether meet default turn-off criterion, if it is, exception occurs in the circuit where illustrating the run signal, then turns off
Controller triggers MPPT unit connected to it and enters string formation shutdown mode by current maximal power tracing pattern, then MPPT is mono-
Member controls each photovoltaic string formation and increases to open-circuit voltage by the corresponding voltage of maximum power, and controller is turned off when reaching open-circuit voltage
The target switch device controlled on the circuit being abnormal disconnects.It will be apparent that when reaching open-circuit voltage, the output of photovoltaic string formation
Electric current levels off to zero, is equivalent to even unloaded in load shedding, and therefore, the requirement for switching device is relatively low, can reliably disconnect；Separately
Outside, after target switch device disconnects, then the input current of inversion unit DC side, voltage and power are just very small, it is not easy to
Phenomena such as leading to overheat, electric leakage, direct current cutoff device being capable of reliable turn-off.Direct current is closed in conclusion the present apparatus can reduce
The requirement of disconnected device, improves the reliable turn-off of inversion unit DC side, prevents photovoltaic system from the hidden danger such as electrical fire occur.
Photovoltaic string formation cutoff device, method and photovoltaic system provided by the present invention are described in detail above.It says
Each embodiment is described by the way of progressive in bright book, and the highlights of each of the examples are the differences with other embodiment
Place, just to refer each other for identical similar portion between each embodiment.For the device disclosed in the embodiment, due to its with
Method disclosed in embodiment is corresponding, so description is fairly simple, reference may be made to the description of the method.It should refer to
Go out, it for those skilled in the art, without departing from the principle of the present invention, can also be to the present invention
Some improvement and modification can also be carried out, these improvement and modification are also fallen within the protection scope of the claims of the present invention.
It should also be noted that, in the present specification, relational terms such as first and second and the like be used merely to by
One entity or operation are distinguished with another entity or operation, without necessarily requiring or implying these entities or operation
Between there are any actual relationship or orders.Moreover, the terms "include", "comprise" or its any other variant meaning
Covering non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only that
A little elements, but also include other elements that are not explicitly listed, or further include for this process, method, article or
The intrinsic element of equipment.In the absence of more restrictions, the element limited by sentence "including a ...", is not arranged
Except there is also other identical elements in the process, method, article or apparatus that includes the element.
Claims (10)
1. a kind of photovoltaic string formation cutoff device, which is characterized in that including be arranged on each photovoltaic group string loop switching device, use
Harvester, the pass that is connect with the harvester and MPPT unit in the run signal for acquiring each photovoltaic group string loop
Disconnected controller；The shutdown controller is used to, when the run signal meets and presets turn-off criterion, trigger the MPPT unit
String formation shutdown mode is entered by current maximal power tracing pattern so that the MPPT unit controls each photovoltaic string formation and returns
The corresponding voltage of routing maximum power increases to open-circuit voltage, and controls target switch device when reaching the open-circuit voltage and break
It opens.
2. photovoltaic string formation cutoff device according to claim 1, which is characterized in that the shutdown controller specifically include with
The A/D conversion equipments of the harvester connection, the signal regulating device being connect with the A/D conversion equipments and the signal
The MCU of conditioning device connection.
3. photovoltaic string formation cutoff device according to claim 1, which is characterized in that the switching device is specially relay
The contact of device, the relay is arranged on the photovoltaic group string loop, the coil of the relay and the shutdown controller
Connection.
4. photovoltaic string formation cutoff device according to claim 1, which is characterized in that further include being arranged in each photovoltaic group
Diode on string loop, the anode of the diode are connect with the photovoltaic string formation, the cathode of the diode with it is described
MPPT unit connects.
5. photovoltaic string formation cutoff device according to claim 1, which is characterized in that the shutdown controller is additionally operable to connecing
The MPPT unit, which is triggered, when receiving external shutdown control instruction enters the string formation shutdown mode.
6. photovoltaic string formation cutoff device according to claim 1, which is characterized in that the shutdown controller is additionally operable to disconnected
After opening the target switch device, triggers the MPPT unit and enter the maximal power tracing pattern.
7. the photovoltaic string formation cutoff device according to claim 1-6 any one, which is characterized in that the harvester tool
Body is current sensor, voltage sensor, temperature sensor, and the corresponding run signal is specially the photovoltaic group string loop
Electric current, the voltage of the photovoltaic group string loop, the photovoltaic group string loop temperature.
8. a kind of photovoltaic string formation cut-off method, which is characterized in that including：
Acquire the run signal of each photovoltaic group string loop；
The run signal is obtained, and when the run signal meets and presets turn-off criterion, triggering MPPT unit is by current
Maximal power tracing pattern enters string formation shutdown mode so that the MPPT unit controls each photovoltaic group string loop by maximum
The corresponding voltage of power increases to open-circuit voltage, and is set in target photovoltaic string formation circuit reaching the open-circuit voltage time control and setting up
On switching device disconnect.
9. photovoltaic string formation cut-off method according to claim 8, which is characterized in that determining that the run signal is unsatisfactory for
After default turn-off criterion, further include：
Judge whether to receive external shutdown control instruction；
If it is, triggering the MPPT unit enters the string formation shutdown mode.
10. a kind of photovoltaic system, which is characterized in that including the photovoltaic string formation cutoff device described in claim 1-7 any one.
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| CN201810386211.1A CN108565891B (en) | 2018-04-26 | 2018-04-26 | Photovoltaic group string turn-off device and method and photovoltaic system |
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| CN108565891B (en) | 2021-02-12 |
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Effective date of registration: 20231211 Address after: Room 208-38, Hengye Building, No. 100 Xiangxing Road, Xiang'an Industrial Zone, Xiamen Torch High tech Zone, Xiamen, Fujian Province, 361000 Patentee after: Xiamen Kehua shuneng Technology Co.,Ltd. Address before: 361000 unit 02, block B, 2nd floor, 32 shiding street, Siming District, Xiamen City, Fujian Province Patentee before: XIAMEN KEHUA HENGSHENG POWER ENERGY CO.,LTD. |