CN215498289U - Quick turn-off system for photovoltaic grid-connected power generation - Google Patents
Quick turn-off system for photovoltaic grid-connected power generation Download PDFInfo
- Publication number
- CN215498289U CN215498289U CN202120341305.4U CN202120341305U CN215498289U CN 215498289 U CN215498289 U CN 215498289U CN 202120341305 U CN202120341305 U CN 202120341305U CN 215498289 U CN215498289 U CN 215498289U
- Authority
- CN
- China
- Prior art keywords
- circuit
- photovoltaic
- switch
- short
- switching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Photovoltaic Devices (AREA)
Abstract
The utility model discloses a quick turn-off system for photovoltaic grid-connected power generation, and relates to the technical field of photovoltaic grid-connected power generation. The photovoltaic power system short circuit shutdown circuit mainly comprises a short circuit shutdown circuit configured on the output side of a photovoltaic assembly and a direct current bypass circuit configured on the output side of a photovoltaic string, wherein the short circuit shutdown circuit mainly comprises a first switch piece, a second switch piece, an energy storage element, a first control module and a first auxiliary power supply, the communication between the photovoltaic assembly and the photovoltaic string is automatically shut off during short circuit, the photovoltaic assembly and the photovoltaic string can be reconnected only through short circuit detection after the photovoltaic assembly is shut off, and the short circuit shutdown circuit of each assembly is subjected to short circuit or voltage reduction through the direct current bypass circuit comprising a third switch piece and a resistance element so as to realize quick shutdown, so that the safety regulation requirement of the photovoltaic system on quick shutdown can be met, and the photovoltaic power system short circuit shutdown circuit is low in cost, reliable and high in safety.
Description
Technical Field
The utility model relates to the technical field of photovoltaic grid-connected power generation, in particular to a rapid turn-off system for photovoltaic grid-connected power generation.
Background
In recent years, photovoltaic power generation has been rapidly developed in the world including china, and is widely installed on roofs of residential houses and industrial and commercial buildings. Direct-current high voltage exists in the photovoltaic modules in the strings under the condition of illumination, a fireman cannot spray water to extinguish a fire when a building is in a fire disaster, and the fire can be relieved only after the modules are completely burnt, so that property loss is caused or personal safety is threatened.
Italian safety is warned on the basis of safety considerations, in which the fire fighters are absolutely not allowed to carry out the extinguishing operation in the case of a voltage on the building; germany also has first implemented fire safety standards and also stipulates in plain text: an additional direct current cut-off device is required to be added between an inverter and a component in the photovoltaic power generation system, and moreover, German insurance company also has clear regulations and does not pay for personal injury caused by electrification of a photovoltaic power station in the fire extinguishing process of firemen; the american fire protection association has modified national electrical codes requiring that in residential photovoltaic power generation systems: when an emergency occurs, the voltage of a direct current end is limited not to exceed 80V to the maximum extent after the alternating current grid-connected port of the photovoltaic power generation system is disconnected.
The legislation of the supporting safe electricity utilization of the European and American countries has been extended to the field of photovoltaic power generation, taking the National Electrical Code (NEC for short) NEC2017-690.12(B) as an example, the European and American countries require that a photovoltaic system installed on the top of a building or on the building must have a quick turn-off function; the requirements on the turn-off speed and the voltage between the inner conductor and the outer conductor of the photovoltaic array and between the conductor and the ground after the turn-off are provided, and the specific requirements are that within 30 seconds after the quick turn-off device is started, the photovoltaic array is out of the range of 1 meter: the voltage is less than or equal to 30V, and the photovoltaic array is within 1 foot (30.5 cm): the voltage is less than or equal to 80V.
To meet the requirements of the above NEC2017-690.12(B), photovoltaic systems need to have a fast turn-off function at the component level. In the prior art, in order to realize a fast turn-off function at a component level, a turn-off controller needs to continuously send a heartbeat communication signal, or a turn-off control module on a direct current bus needs to send a periodic excitation pulse source; in the two schemes, corresponding sending modules need to be added in the photovoltaic inversion system, and extra receiving modules need to be arranged in a shutoff device or a power optimizer of the photovoltaic assembly.
Due to the problems, the problems of high cost, reliability and the like are inevitably faced when the photovoltaic module is turned off at the level, and meanwhile, the simple turn-off function generates the self-power consumption of the turn-off device, so that the commercial application is difficult at present in China, and the potential safety production hazard exists in the photovoltaic power generation industry of China.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects in the prior art, the utility model mainly aims to provide a quick turn-off system for grid-connected photovoltaic power generation. On one hand, the utility model reduces heartbeat or periodic excitation pulse signal source receiving modules in the photovoltaic shutoff device and the power optimizer and signal source sending modules in the photovoltaic inversion system, realizes component-level shutoff of the photovoltaic system with low cost and high reliability, and reduces the internal and external voltages of the photovoltaic array to be within a safe range in a very short time. On the other hand, the method has the advantages of simple available steps and reliable implementation, can conveniently and quickly recover the photovoltaic power generation after the fault is removed, can provide a fault point for shielding power generation loss and recovering and preventing component hot spots and direct current arcs for a photovoltaic system when being applied to a photovoltaic power optimizer, and solves the problem that the current photovoltaic component level shutdown is difficult to realize large-scale commercialization.
In order to achieve the purpose, the utility model adopts the following technical scheme:
the utility model provides a quick turn-off system for photovoltaic grid-connected power generation, which is configured in a photovoltaic grid-connected power generation system and comprises a photovoltaic series connection body formed by connecting a plurality of photovoltaic units in series, wherein the quick turn-off system comprises a short circuit turn-off circuit configured on the output side of the photovoltaic units and a direct current bypass circuit configured on the output side of the photovoltaic series connection body, and the output ends of the short circuit turn-off circuits are connected in series to serve as the output end of the photovoltaic series connection body;
the short-circuit turn-off circuit comprises a first switch piece, a second switch piece, an energy storage element, a first control module and a first auxiliary power supply; the first switch piece and the second switch piece are connected to a connecting loop of the photovoltaic unit and the photovoltaic serial body, and when any one of the first switch piece and the second switch piece is turned off, the connection of the photovoltaic unit and the photovoltaic serial body is disconnected; the energy storage element is connected between the first switch piece and the second switch piece, the photovoltaic unit and the energy storage element can be communicated by the conduction of the first switch piece, and the energy storage element and the photovoltaic series connection body can be communicated by the conduction of the second switch piece; the first auxiliary power supply is electrically connected to the output end of the photovoltaic unit and is used for supplying power to be connected to a first control module, the first control module is controlled to be connected to a first switch piece and a second switch piece through a switch signal, and the first control module can perform short-circuit detection; the direct current bypass circuit comprises a third switching element and a resistance element which are connected in series, and the third switching element and the resistance element are connected in parallel on the output side of the photovoltaic series connection body; the direct current bypass circuit further comprises a second control module (H), and the second control module (H) is connected to the third switch in a control mode.
The working principle of the technical scheme is as follows: after the third switching element is conducted, each first auxiliary power supply is turned off at least because the voltage is lower than the operation requirement, so that any one of the first switching element and the second switching element is turned off, and the connection between the photovoltaic unit and the photovoltaic serial connection body is disconnected; at least when the first auxiliary power supply is restarted due to the direct current bypass circuit, the first control module respectively and independently controls the conduction of the first switch piece and the second switch piece, so that the energy storage element is accessed to the photovoltaic series connection body after power is taken from the photovoltaic unit, whether a short-circuit condition is met is obtained and judged according to the change condition of the electrical parameter of the energy storage element, and each short-circuit turn-off circuit keeps the disconnection of the photovoltaic unit and the photovoltaic series connection body before the short-circuit is confirmed to be removed.
Above-mentioned quick turn-off system, optionally have, the third switch spare is the normal close type switch spare, direct current bypass circuit still includes second control module and second auxiliary power supply, the second auxiliary power supply is got the electricity and is connected in inverter system or the output side of direct current collection flow box, second auxiliary power supply is connected in second control module, second control module control connection is in the third switch spare.
In the above quick turn-off system, optionally, the dc bypass circuit further includes a manual switch, and the manual switch can control the third switch to be turned on.
In the above fast turn-off system, optionally, the short-circuit turn-off circuit is configured in a photovoltaic power optimizer, the optimizer includes a power conversion module, a control module and an auxiliary power supply, the first control module is used as the control module of the optimizer, the first auxiliary power supply is used as the auxiliary power supply of the optimizer, and the first switch, the second switch and the energy storage element are configured on a positive loop and a negative loop of the power conversion module; when the optimizer normally operates, the first control module sets the electric parameter of the output end of the photovoltaic unit at the maximum power point, and when the optimizer starts, the first control module controls the first switch piece, the second switch piece and the energy storage element to carry out short-circuit detection.
Optionally, in the above fast turn-off system, the power conversion module is a Buck-type or Boost-Buck-type dc chopper circuit having an output capacitor; the output capacitor is used as an energy storage element of the short-circuit turn-off circuit;
in the short-circuit test process, the first control module acquires and records voltage parameters of the output capacitor conducted to the photovoltaic unit to obtain electricity and the power acquisition system conducted to the output capacitor, so as to acquire voltage parameter difference for judging whether the short-circuit condition is met.
Optionally, in the above fast turn-off system, the power conversion module is a Buck-type or Boost-Buck-type dc chopper circuit having an input capacitor and an output capacitor;
in the short-circuit test process, the first control module acquires voltage parameter difference for judging whether the short-circuit condition is met by respectively acquiring the voltage parameter difference of the input capacitor and the output capacitor when the collection output capacitor is conducted to the power acquisition system.
Optionally, in the above fast turn-off system, the first switch device is used as a switch element connected in series to the positive or negative circuit in the dc chopper circuit, the second switch device is a switch element connected in series to the positive or negative circuit between the output end of the dc chopper circuit and the output end of the optimizer, and the first switch device and the second switch device of at least one of the first switch device and the second switch device are normally open switch devices.
Optionally, in the above fast turn-off system, the power conversion module is a Buck dc chopper circuit, which includes an input capacitor, a switching element serving as the first switching element, an inductor, and an output capacitor serving as the energy storage element; the first switch piece, the inductor and the second switch piece are sequentially connected in series to the positive circuit of the direct-current chopper circuit, the positive circuit and the negative circuit of the input capacitor are connected between the input end of the power conversion module and the first switch piece in parallel, and the positive circuit and the negative circuit of the output capacitor are connected between the inductor and the second switch piece in parallel.
The quick turn-off system optionally comprises an energy storage element and a first control module, wherein the energy storage element is a capacitor element which is connected in parallel with a positive and negative connecting loop of the photovoltaic unit and the photovoltaic series body, and the first control module acquires voltage parameters of the capacitor element and judges whether a short-circuit condition is met according to difference conditions before and after electricity is taken from the photovoltaic unit and the photovoltaic series body is connected.
Optionally, in the above fast turn-off system, the first control module includes a control unit for controlling the operation of the short-circuit turn-off circuit, a collection unit, an operation unit, a judgment unit, a counting unit, and a driving unit;
the control unit is used for controlling the second switch piece to be kept off, then controlling the first switch piece to be conducted so that the energy storage element obtains electric power from the photovoltaic unit, controlling the first switch piece to be turned off, and then controlling the second switch piece to be conducted so that the energy storage element is connected to the electric power obtaining system;
the acquisition unit is used for acquiring the electric parameter information of the energy storage element during electric power acquisition and the electric parameter information of the electric power acquisition system;
the arithmetic unit is used for acquiring the difference of the electrical parameter information in the power state and the access system state;
the judging unit is used for judging the electric parameter information parameters and driving the control unit to execute corresponding operation;
the control unit controls the first switching piece and the second switching piece to be simultaneously conducted by switching value under the condition that the short circuit does not exist; under the condition that the short circuit is determined, the switching-off of the first switching piece and the second switching piece is controlled by the switching value, and under the condition that the short circuit is not determined, the short circuit detection is executed by the control unit again after the time delay setting time;
the counting unit counts the execution times of the first control unit executed because short circuit is not confirmed, and determines that short circuit is determined when the execution times exceed a preset time;
the driving unit drives the first switch piece and the second switch to be switched off and on according to the switching value control command.
Compared with the prior art, the utility model has the following beneficial effects:
(1) according to the photovoltaic series connection structure, the photovoltaic series connection body is in short circuit or is connected with the resistor in parallel through the direct current bypass circuit so as to reduce voltage, so that an auxiliary power supply in a photovoltaic assembly provided with the short circuit turn-off circuit stops running at least because the auxiliary power supply is lower than a turn-off voltage, and meanwhile, a switch piece of the short circuit turn-off circuit automatically disconnects the photovoltaic assembly from the photovoltaic series connection body, so that rapid turn-off is realized; meanwhile, after the auxiliary power supply is turned on again after the auxiliary power supply is disconnected, the control module of the short-circuit turn-off circuit firstly maintains the disconnection of the photovoltaic module and the photovoltaic serial body, and the short-circuit detection is carried out by utilizing the principle that the energy storage element generates the change of the electrical parameters when the short circuit exists; in the detection process, the photovoltaic module and the power acquisition circuit are kept disconnected, and the photovoltaic module is ensured not to output power to the outside before the short circuit condition is relieved; when the circuit is turned off due to short circuit caused by other reasons, the circuit is automatically restarted after short circuit detection, so that the intellectualization of the photovoltaic grid-connected system is realized; in the process of rapid turn-off, heartbeat or periodic excitation pulse signals for communication do not need to be set in a turn-off device or an optimizer, the arrangement of a receiving module and a sending module is reduced, the cost is reduced, the rapid turn-off of a photovoltaic power generation system on a photovoltaic module can be realized with high reliability, the internal and external voltages of a photovoltaic array are reduced to a safe range within a very short time, and the requirements of safety regulations of NEC2017-690.12(B) are met; and only a small amount of electric power of the energy storage element is used for testing, the measurement process is safe and reliable, and the system is not burdened.
(2) The third switch element is a normally closed switch element, and is controlled to be turned off when the inverter system normally operates so as to maintain operation, but is automatically turned on when the inverter system stops due to fault or is actively stopped due to failure of the inverter system, and is further matched with the short circuit turn-off circuit to quickly turn off each photovoltaic component in the system, meanwhile, the resistance element can reduce the output voltage of the photovoltaic string to a safe range, and simultaneously quickly consume the electric energy of the inverter input capacitor and various energy storage elements in the photovoltaic string, so that the safety of the photovoltaic power generation system after being turned off is improved.
(3) According to the photovoltaic power optimizer, the short circuit shutdown circuit can be configured in the photovoltaic power optimizer, on one hand, the photovoltaic power optimizer can enable the photovoltaic module to operate at the maximum power point, and the power generation efficiency is improved; on the other hand, the short circuit turn-off circuit can utilize the control module of the optimizer to carry out acquisition, operation, judgment and control when being turned off and started, and can also utilize the switching element and the energy storage element in the power conversion module of the optimizer. Compared with the traditional shut-off device and the optimizer, the special receiving module and the special sending module are also reduced, and the manufacturing cost of the power generation system is reduced.
The utility model will be further described with reference to the accompanying drawings.
Drawings
Fig. 1 is a schematic structural diagram of a fast turn-off system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a short-circuit shutdown circuit according to an embodiment of the utility model;
fig. 3 is a schematic structural diagram of a photovoltaic power optimizer configured with a short-circuit shutdown circuit according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a short-circuit shutdown control structure of a first control module according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a power conversion control structure of a first control module according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a photovoltaic inverter system configured with a dc bypass circuit according to an embodiment of the present invention.
Detailed Description
To better illustrate the objects, technical solutions and advantages of the present invention, the following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings and examples. The following examples are intended to illustrate the utility model, but are not intended to limit the scope of the utility model.
As shown in fig. 1, a system for quickly turning off a grid-connected pv power generation system according to an embodiment of the present invention is configured in a grid-connected pv power generation system, and includes a series-connected pv cell formed by connecting a plurality of pv cells in series. The photovoltaic unit is a photovoltaic module a in this embodiment, and may also be a photovoltaic string B including a plurality of photovoltaic modules a in other embodiments, or a serial body of a part of photovoltaic cells in a photovoltaic module a, and the serial body of the photovoltaic cells corresponds to the photovoltaic string B in this embodiment. The quick turn-off system includes a short-circuit turn-off circuit E4 and a dc bypass circuit P.
Referring to fig. 1, a short-circuit shutdown circuit E4 is connected to the output side of the photovoltaic module a, and the output ends of a plurality of short-circuit shutdown circuits E4 are connected in series to serve as the output end of the photovoltaic string B. The number of the photovoltaic modules A is multiple, and A-1, A-2, … and A-n in the figure; the number of short-circuit shutdown circuits E4 corresponds. In the figure, E-1, E-2, … and E-n are power optimizers E, each power optimizer E is provided with a short-circuit turn-off circuit E4, the number of the photovoltaic string B is multiple, and the output ends of the photovoltaic string B are connected to a photovoltaic inverter system J. In other embodiments, the photovoltaic string B may further be connected to an input end of the dc combiner box, and an output end of the dc combiner box is connected to the inverter system J. The dc bypass circuit P is disposed on the output side of the pv string B, specifically, in the inverter system J in this embodiment, and may be disposed in the dc combiner box in other embodiments. The short-circuit shutdown circuit E4 can be configured to operate at the output end of the photovoltaic module a alone or in the power optimizer E.
Specifically, the short-circuit shutdown circuit E4 includes a first switch device S1, a second switch device S2, an energy storage element C, a first control module E2, and a first auxiliary power supply E3. The first switch device S1 and the second switch device S2 are connected in series on a positive circuit of the photovoltaic module A communicated with the photovoltaic group string B, and the power generation circuit of the photovoltaic module A can be disconnected by turning off the first switch device S1 and the second switch device S2. In the present embodiment, the energy storage element C is a capacitive element R connected in parallel between the first switching device S1 and the second switching device S2 in the communication circuit. In other embodiments, the energy storage element C may also be an inductor, and whether the external circuit is short-circuited is determined by measuring the current or the energy storage condition of the inductor. When the first switch element S1 is turned on, the capacitor element R communicates with the photovoltaic module a; when the second switch S2 is turned on, the capacitor R is connected to the string B. The first auxiliary power supply E3 is connected in parallel with the positive and negative loops of the output end of the photovoltaic module A, and the first switch piece S1 and the second switch piece S2 are normally open switch pieces. When the voltage of the positive circuit and the negative circuit is lower than the voltage of the first auxiliary power supply E3 due to the occurrence of a short circuit or the like, the first control module E2 stops operating, and the first switch device S1 is turned off by one step by the second switch device S2, so that the photovoltaic module A is disconnected from the connection circuit of the photovoltaic module string B connected with the photovoltaic module A. After the first switching device S1 and the second switching device S2 are turned off, the first auxiliary power source E3 is isolated from the short circuit condition of the external circuit, and the power supply from the photovoltaic module a is recovered. The first control module E2 controls the conduction of the first switch element S1 and the second switch element S2 separately, so that the capacitor is accessed to the power acquisition system after being powered from the photovoltaic module A, the capacitor is acquired, whether a short-circuit condition is met or not is judged according to the difference condition of voltage parameters at two ends of the capacitor, and the first switch element S1 and the second switch element S2 are conducted simultaneously only after the short-circuit condition is determined not to be met, and the connection between the photovoltaic unit and the photovoltaic module string B is restored. On one hand, the short-circuit turn-off circuit E4 utilizes the first switch piece S1 and the second switch piece S2 to automatically turn off and perform short-circuit protection when a short circuit occurs in the power acquisition system; on the other hand, the energy storage element C is used to test whether the external circuit is short-circuited by controlling the on and off of the first switching element S1 and the second switching element S2.
Referring to fig. 1 and 6, in cooperation with the short-circuit shutdown circuit E4, the dc bypass circuit P of the present invention is configured in the photovoltaic inverter system J, which includes a third switching element S3, a resistive element, a second control module H, a second auxiliary power source Q, and a manual switching element K. The photovoltaic inverter system J comprises a Boost type conversion circuit J1 and an inverter circuit J2. The conversion circuit J1 is connected to each photovoltaic string B, obtains the electric power at the output end of the photovoltaic string B, converts the electric power into electric power of another electric parameter and outputs the electric power to the inverter circuit J2, and the inverter circuit J2 inverts the direct-current electric power into alternating-current electric power for supply to a phase grid. The third switch element S3 and the resistor element are connected in series, and the output terminal thereof is connected in parallel to the input terminal of the inverter circuit J1. In this embodiment, the third switch device S3 is a P-type normally-closed fet M3, and in other embodiments, it may also be a normally-closed relay or other normally-closed fully-controlled semiconductor switch device.
It should be noted that, the resistance element is a power resistor, and its resistance value is small, so that when the resistance element is connected to the photovoltaic string B to form a loop, not only the first auxiliary power sources E3 are lower than the turn-off voltage, but also the output voltage of the photovoltaic string B can be reduced to within the safety requirement, and at the same time, the power of the input end capacitor of the conversion circuit can be consumed quickly, and the power of each output end capacitor in the photovoltaic string B can be consumed quickly, so as to further ensure the safety of the system after turn-off.
It should be noted that an input end of the second auxiliary power supply Q is connected to an alternating current side of the inverter system J, an output end of the second auxiliary power supply Q is in power supply connection with a second control module H, the second control module H is in control connection with a third switching element S3, a conversion circuit J1 and an inverter circuit J2, and an input of the second control module H is connected with a manual switching element K. The manual switch member K is an emergency off button. When the manual switch K is actively pressed, the second control module H controls the switch of the inverter circuit J2 to be turned off, so that the inverter system J stops running, the communication between the inverter system J and a power grid is turned off, the second auxiliary power supply Q is turned off, the second control module H is further turned off, and the third switch S3 is kept in a conducting state due to the fact that driving is lost, and therefore the photovoltaic modules A are rapidly turned off in an emergency. When the inverter system J is shut down due to other reasons, the second auxiliary power supply Q loses power and is turned off, the second control module H is turned off, and the third switch element S3 is further turned on due to loss of driving, so that each photovoltaic module a is rapidly turned off in an emergency.
It will be appreciated that the other factors associated with the short circuit of the non-dc bypass circuit P, resulting in the disconnection of the photovoltaic module a by the short shutdown circuit E4, may be automatically initiated upon detection of a short. After the first switching device S1 and the second switching device S2 are turned off, the first auxiliary power source E3 is isolated from the short circuit condition of the external circuit, and the power supply from the photovoltaic module a is recovered. The first control module E2 controls the conduction of the first switch element S1 and the second switch element S2 separately, so that the capacitor is accessed to the power acquisition system after being powered from the photovoltaic module A, whether a short-circuit condition is met is judged according to the difference condition of voltage parameters at two ends of the capacitor, each short-circuit turn-off circuit E4 keeps the disconnection of the photovoltaic module A and the photovoltaic module string B before the short-circuit is confirmed to be relieved, the first switch element S1 and the second switch element S2 are conducted simultaneously only after the short-circuit condition is confirmed to be not met, and the connection of the photovoltaic unit and the power acquisition system is recovered.
As a feature of the embodiment of the present invention, the fast turn-off system including the short-circuit turn-off circuit E4 and the dc bypass circuit P can satisfy the requirement of the safety regulation 690.12(B) in the case of an emergency active stop and a failure sudden stop, and can realize automatic turn-off of the photovoltaic array, and reduce the voltage of the photovoltaic string B to the safety requirement, whereas in the case of turn-off of the photovoltaic module a caused by other factors other than a short circuit, the short-circuit turn-off circuit E4 can realize automatic start after short-circuit detection, and does not need to establish communication between the photovoltaic module a and central control, and generally, a simple and low-cost circuit structure is used to realize fast turn-off and safe self-start of the photovoltaic module a by the photovoltaic grid-connected power generation system.
As shown in fig. 2, a photovoltaic power optimizer E configured with the short circuit shutdown circuit E4 includes a power conversion module E1, a control module and an auxiliary power supply according to an embodiment of the present invention. It can be understood that, when the short-circuit shutdown circuit E4 is configured in the photovoltaic power optimizer E, the control module and the auxiliary power supply can be shared with the optimizer E, so as to simplify the circuit structure and reduce the hardware cost. In this embodiment, in the short-circuit shutdown circuit E4, a first control module E2 is used as a control module of the optimizer E, a first auxiliary power supply E3 is used as an auxiliary power supply of the optimizer E, and the first switch device S1, the second switch device S2 and the energy storage element C are disposed on a positive-negative loop of the power conversion module E1; when the optimizer E operates normally, the first control module E2 sets the electrical parameter at the maximum power point of the output end of the photovoltaic module A, and when the optimizer E starts, the first control module E2 controls the first switching element S1, the second switching element S2 and the energy storage element C to perform short circuit detection. The power conversion module E1 may be a Buck-type or Boost-Buck-type dc chopper circuit.
As shown in fig. 3, the specific BUCK photovoltaic power optimizer E configured with the short-circuit shutdown circuit E4 is that, on the basis of the circuit structure of the optimizer E in fig. 2, the short-circuit shutdown circuit E4 and the optimizer E can also share the first switching device S1 and the capacitive element R due to the structure of the dc chopper circuit having a switching device and a capacitor.
The power conversion module E1 includes an input capacitor C1, a first switch transistor M1, an inductor L, a freewheeling diode D1, an output capacitor C2, a second switch transistor M2, and a bypass diode D2. The first switch tube M1, the inductor L and the second switch tube M2 are connected in series with the positive pole PV + of the dc chopper circuit in sequence. More specifically, the first switch transistor M1 and the second switch transistor M2 are n-type normally-open switch fets, and in other embodiments, the first switch transistor M1 and the second switch transistor M2 may also be other fully-controlled switches. The sources of the first switch tube M1 and the second switch tube M2 are connected to the output side of PV +, the drains of the first switch tube M1 and the second switch tube M2 are connected to the input side of PV +, and the gates of the first switch tube M1 and the second switch tube M2 are connected to the first control module E2, respectively. The auxiliary capacitor and the input capacitor C1 are respectively connected in parallel on the positive pole circuit PV + and the negative pole circuit PV-of the direct current chopper circuit and are positioned between the input end of the direct current chopper circuit and the second switching tube M2. The anode of the freewheeling diode D1 is connected to the negative return PV-, and the cathode of the freewheeling diode D1 is connected to the positive return PV +, and is located between the first switching transistor M1 and the inductor. The output capacitor C2 is connected in parallel to PV + and PV-of the DC chopper circuit and is located between the inductor L and the second switch tube M2. The bypass diode D2 is connected in parallel to PV + and PV-of the DC chopper circuit and is located between the second switch tube M2 and the output end of the DC chopper circuit. The input capacitor C1 and the output capacitor C2 are used for filtering of a chopper circuit, the first switching tube M1 controls chopping conversion of the photovoltaic module A to the inductor L, and the freewheeling diode D1 is used for maintaining an output level.
It should be noted that the first switching tube M1 constitutes an element of a Buck-type dc chopper circuit, and can be used for controlling and implementing power conversion of the dc chopper circuit by a pulse modulation signal (pulse width modulation PWM or pulse frequency modulation PFM), and at the same time, serves as the first switching device S1 of the short-circuit shutdown circuit E4; the output capacitor C2 is used as an energy storage element C of the short-circuit turn-off circuit E4; the second switch tube M2 is added on the output side of the dc chopper circuit as the second switch device S2 of the short-circuit shutdown circuit E4. The short-circuit turn-off circuit E4 and the direct-current chopper circuit share components, and the circuit of the photovoltaic power optimizer E is simplified. When the bypass diode D2 is used as the optimizer E in the off state, the current of the pv string B can be conducted through the bypass diode D2.
It should be noted that there is a difference in the electrical quantity of the energy storage element C in the two control states of the switching device. On one hand, under two control states, the voltage parameter of the output capacitor C2 when being connected to the photovoltaic module a is respectively collected and recorded, and is compared with the voltage parameter of the output capacitor C2 when being connected to the photovoltaic module string B, so as to obtain the voltage difference of the output capacitor C2 in the short circuit test process. On the other hand, the input end of the direct current chopper circuit is provided with the input capacitor C1 for filtering, so as to prevent the fluctuating current of the power conversion from reversely influencing the photovoltaic module a, and when the output capacitor C2 is connected to the photovoltaic string B, the voltage parameters of the input capacitor C1 and the output capacitor C2 can be collected and compared, so as to obtain the voltage difference of the output capacitor C2 in the short-circuit test process. In the latter scheme, the process of output storage can be reduced, and errors of the previous and subsequent measurements can be reduced.
As shown in fig. 4 and 5, which are structural diagrams of a first control module E2 according to an embodiment of the present invention. The first control module E2 includes a control unit 21, a collecting unit 22, an arithmetic unit 23, a judging unit 24, a counting unit 25, a driving unit 26 and a communication unit 27. The acquisition unit 22 may acquire the current parameter Ipv and the voltage parameter Vpv at the input end of the power conversion module, and the output capacitor C2, that is, the voltage parameter Vout at the output end of the power conversion module, and the acquisition is implemented by a sensor disposed at an acquisition position, amplified by an amplifier, and processed by a processor into an electrical signal capable of being operated. The arithmetic unit 23 may be disposed in the processor and may operate the collected electrical parameters. The judging unit 24 may be provided in the processor to judge the short circuit condition or the current power condition according to the result of the operation. The control unit 21 may be disposed in the processor, and includes performing corresponding short circuit detection control under a trigger operation condition, such as initial start after power is obtained; and carrying out corresponding control operation according to the judged structure. The counting unit 25 may be provided in the processor to count a result of the determination unit 24, or to count an operation of the control unit 21, to output the result when a set limit of the count is reached, or to clear the result under set conditions. The communication unit 27 can be zigbee, WIFI or bluetooth wireless communication, and a second control module H is configured in the inverter system J or the dc combiner box, the second control module H is configured with a communication device matched with the optimizer E, and the first control module E2 can give an alarm to the second control module H through the communication unit 27 when a short-circuit fault occurs.
Specifically referring to fig. 4, in the control process of restarting the optimizer E through the short circuit test, specifically, the control unit 21 is configured to control the second switching tube M2 to remain off, then control the first switching tube M1 to be on, so that the output capacitor C2 obtains power from the photovoltaic unit, control the first switching tube M1 to become off, and then control the second switching tube M2 to be on, so that the output capacitor C2 is connected to the power obtaining system; the acquisition unit 22 is used for acquiring the voltage parameter information of the output capacitor C2 during power acquisition and counting in the power acquisition system; the operation unit 23 is used for acquiring the voltage parameter information difference in the power state and in the access system state; the judging unit 24 is used for judging the voltage parameter information parameter and driving the control unit 21 to execute corresponding operation; under the condition that the control unit 21 judges that no short circuit exists, the simultaneous conduction of the first switch tube M1 and the second switch tube M2 is controlled by the switching value; under the condition of determining that the short circuit is determined, the switching-off of the first switching tube M1 and the second switching tube M2 is controlled by switching value, under the condition of determining that the short circuit is not determined, the control unit 21 carries out short circuit detection again after delaying for a set time; the counting unit 25 counts the number of times of execution of the first control unit 21 performed without confirming the short circuit, and determines that the short circuit is confirmed when the number of times exceeds a preset number; the driving unit 26 controls the first switching tube M1 and the second switch to be turned off and on according to the switching value control command; the communication unit 27 gives an alarm to the second control module H after determining that the short circuit is confirmed.
Referring specifically to fig. 5, in the control process of power conversion when the optimizer E operates normally, specifically, the collecting unit 22 is configured to collect voltage and current parameters at the output end of the photovoltaic unit; the operation unit 23 is used for calculating a power parameter from the voltage current parameter; the judging unit 24 is configured to judge a variation characteristic of the power parameter and drive the control unit 21 to perform a corresponding operation; the control unit 21 is used for outputting a pulse modulation signal according to the change of the power parameter; the driving unit 26 is configured to control the operation of the switching element of the power conversion module E1 with the pulse-modulated driving signal to set the electrical parameter at the maximum power point at the output of the photovoltaic unit.
It should be noted that, the short-circuit shutdown circuit E4 of the present invention has a restart function through short-circuit detection, and when the short-circuit shutdown circuit E4 is turned off due to the dc bypass circuit P being in the on state, the result of shutdown of the optimizer E is obtained through the short-circuit detection step, and in this case, after the reason for fast shutdown is eliminated, the optimizer E is restarted after the second control module H actively sends a startup instruction. In the face of a short circuit fault such as a parallel arc event, the optimizer E will automatically shut down and shut down as a result of failing to pass the short circuit test without the need for manual switching K or ac side disconnection. In the face of shutting down after darkness and the next morning, the auxiliary power supply reaches the starting voltage for the first time, and the optimizer E is automatically started through short-circuit detection smoothly. When the operation of the optimizer E is interrupted due to overcurrent and other non-short-circuit faults, the optimizer E can restart the operation through short-circuit detection. Comprehensively, realize safe self-starting through short circuit turn-off circuit E4 to on the basis of reducing communication hardware setting, realize photovoltaic module A's quick turn-off.
The foregoing embodiments have been described primarily for the purposes of illustrating the general principles, and features and advantages of the utility model. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the utility model as claimed.
Claims (9)
1. A fast turn-off system of photovoltaic grid-connected power generation is configured in a photovoltaic grid-connected power generation system, and comprises a photovoltaic series-connected body formed by connecting a plurality of photovoltaic units in series, and is characterized in that the fast turn-off system comprises a short-circuit turn-off circuit (E4) configured on the output side of the photovoltaic units and a direct current bypass circuit (P) configured on the output side of the photovoltaic series-connected body, and the output ends of the short-circuit turn-off circuits (E4) are connected in series to serve as the output end of the photovoltaic series-connected body;
the short circuit shutdown circuit (E4) comprises a first switch piece (S1), a second switch piece (S2), an energy storage element (C), a first control module (E2) and a first auxiliary power supply (E3); the first switching piece (S1) and the second switching piece (S2) are connected to a connection loop of the photovoltaic unit and the photovoltaic serial body, and the connection of the photovoltaic unit and the photovoltaic serial body is disconnected when any one of the first switching piece (S1) and the second switching piece (S2) is turned off; the energy storage element (C) is connected between a first switching piece (S1) and a second switching piece (S2), the conduction of the first switching piece (S1) can communicate the photovoltaic unit with the energy storage element (C), and the conduction of the second switching piece (S2) can communicate the energy storage element (C) with the photovoltaic series connection body; the first auxiliary power supply (E3) is electrically connected to the output end of the photovoltaic unit and is in power supply connection with a first control module (E2), the first control module (E2) is in control connection with a first switch piece (S1) and a second switch piece (S2) through a switch signal, and the first control module can perform short-circuit detection;
the direct current bypass circuit (P) includes a third switching element (S3) and a resistance element connected in series, which are connected in parallel on the output side of the photovoltaic series connection body; the direct current bypass circuit (P) further comprises a second control module (H) which is in control connection with a third switch element (S3).
2. The rapid turn-off system according to claim 1, wherein the third switching element (S3) is a normally closed switching element, the dc bypass circuit (P) further comprises a second auxiliary power supply (Q) electrically connected to the output side of the inverter system (J) or the dc combiner box, and the second auxiliary power supply (Q) is electrically connected to the second control module (H).
3. Fast turn-off system as claimed in claim 1, characterized in that said direct current bypass circuit (P) further comprises a manual switching element (K), said manual switching element (K) controlling the conduction of the third switching element (S3).
4. Fast turn-off system according to claim 1, characterized in that the short-circuit turn-off circuit (E4) is arranged in a photovoltaic power optimizer (E) comprising a power conversion module (E1), a control module and an auxiliary power supply, the first control module (E2) acting as the control module of the optimizer (E), the first auxiliary power supply (E3) acting as the auxiliary power supply of the optimizer (E), the first switch (S1), the second switch (S2) and the energy storage element (C) being arranged in the positive and negative circuit of the power conversion module (E1).
5. Fast turn-off system as claimed in claim 4, characterized in that the power conversion module (E1) is a Buck-type or Boost-Buck-type direct current chopper circuit with an output capacitance (C2); the output capacitor (C2) is used as an energy storage element (C) of the short-circuit turn-off circuit (E4).
6. Fast turn-off system as claimed in claim 4, characterized in that the power conversion module (E1) is a Buck-type or Boost-Buck-type direct current chopper circuit having an input capacitance (C1) and an output capacitance (C2).
7. The fast turn-off system as claimed in claim 4, wherein said first switching device (S1) is a switching element connected in series in the positive or negative loop of the DC chopper circuit, said second switching device (S2) is a switching element connected in series in the positive or negative loop between the output of the DC chopper circuit and the output of the optimizer (E), and said first switching device (S1) and said second switching device (S2) of at least one of them are normally open switching devices.
8. The fast turn-off system of claim 4, characterized in that the power conversion module (E1) is a Buck Buck DC chopper circuit comprising an input capacitance (C1), a switching element as the first switching element (S1), an inductor (L), an output capacitance (C2) as the energy storage element (C); the first switch (S1), the inductor (L) and the second switch (S2) are sequentially connected in series with a positive circuit of the direct-current chopper circuit, a positive circuit and a negative circuit of the input capacitor (C1) are connected between the input end of the power conversion module (E1) and the first switch (S1) in parallel, and a positive circuit and a negative circuit of the output capacitor (C2) are connected between the inductor (L) and the second switch (S2) in parallel.
9. The fast turn-off system according to claim 1, wherein the energy storage element (C) is a capacitive element (R) connected in parallel to the positive and negative connection loops of the pv cell and the pv string, and the first control module (E2) obtains and determines whether the short-circuit condition is satisfied according to a difference between voltage parameters of the capacitive element (R) before and after the pv cell is powered and connected to the pv string.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120341305.4U CN215498289U (en) | 2021-02-04 | 2021-02-04 | Quick turn-off system for photovoltaic grid-connected power generation |
| PCT/CN2022/075202 WO2022166928A1 (en) | 2021-02-04 | 2022-01-30 | Rapid shutdown system for photovoltaic grid-connected power generation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120341305.4U CN215498289U (en) | 2021-02-04 | 2021-02-04 | Quick turn-off system for photovoltaic grid-connected power generation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215498289U true CN215498289U (en) | 2022-01-11 |
Family
ID=79762295
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120341305.4U Active CN215498289U (en) | 2021-02-04 | 2021-02-04 | Quick turn-off system for photovoltaic grid-connected power generation |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN215498289U (en) |
| WO (1) | WO2022166928A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022166928A1 (en) * | 2021-02-04 | 2022-08-11 | 深圳市中旭新能源有限公司 | Rapid shutdown system for photovoltaic grid-connected power generation |
| WO2022166931A1 (en) * | 2021-02-04 | 2022-08-11 | 深圳市中旭新能源有限公司 | Power optimizer having short circuit protection, and photovoltaic power generation system |
| CN115663769A (en) * | 2022-12-29 | 2023-01-31 | 深圳市中旭新能源有限公司 | Photovoltaic power generation system direct-current parallel arc protection and positioning system and method |
| WO2023134027A1 (en) * | 2022-01-13 | 2023-07-20 | 杭州禾迈电力电子股份有限公司 | Multi-input turn-off device and control method therefor, and photovoltaic power generation system |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203456934U (en) * | 2013-09-03 | 2014-02-26 | 深圳市金威源科技股份有限公司 | Solar photovoltaic system control apparatus |
| US10651735B2 (en) * | 2017-02-06 | 2020-05-12 | Futurewei Technologies, Inc. | Series stacked DC-DC converter with serially connected DC power sources and capacitors |
| CN108512245A (en) * | 2017-09-14 | 2018-09-07 | 上海盐巴信息科技有限公司 | The photovoltaic system and its control method of component level shutdown can be realized automatically |
| CN109038669B (en) * | 2018-08-23 | 2024-01-05 | 嘉兴爱索乐信息技术有限公司 | Photovoltaic system for realizing automatic shutdown of assembly level |
| CN111585307A (en) * | 2020-06-15 | 2020-08-25 | 阳光电源股份有限公司 | Starting method, application device and system of photovoltaic rapid turn-off system |
| CN215498289U (en) * | 2021-02-04 | 2022-01-11 | 广州中旭新能源有限公司 | Quick turn-off system for photovoltaic grid-connected power generation |
-
2021
- 2021-02-04 CN CN202120341305.4U patent/CN215498289U/en active Active
-
2022
- 2022-01-30 WO PCT/CN2022/075202 patent/WO2022166928A1/en active Application Filing
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022166928A1 (en) * | 2021-02-04 | 2022-08-11 | 深圳市中旭新能源有限公司 | Rapid shutdown system for photovoltaic grid-connected power generation |
| WO2022166931A1 (en) * | 2021-02-04 | 2022-08-11 | 深圳市中旭新能源有限公司 | Power optimizer having short circuit protection, and photovoltaic power generation system |
| WO2023134027A1 (en) * | 2022-01-13 | 2023-07-20 | 杭州禾迈电力电子股份有限公司 | Multi-input turn-off device and control method therefor, and photovoltaic power generation system |
| CN115663769A (en) * | 2022-12-29 | 2023-01-31 | 深圳市中旭新能源有限公司 | Photovoltaic power generation system direct-current parallel arc protection and positioning system and method |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2022166928A1 (en) | 2022-08-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN215498289U (en) | Quick turn-off system for photovoltaic grid-connected power generation | |
| WO2016078507A1 (en) | Photovoltaic intelligent power supply | |
| CN215498288U (en) | But short-circuit protection's power optimizer and photovoltaic power generation system | |
| CN102253278B (en) | Startup condition detection method suitable for photovoltaic inverter with DC/DC (direct current/direct current) | |
| CN102222904B (en) | Direct-current dual-circuit power supply for supplying power | |
| WO2018137355A1 (en) | System having black start function, and black start method therefor | |
| CN109494793B (en) | Lithium-capacitor-based photovoltaic graded energy storage system with primary frequency modulation function | |
| CN111817666B (en) | Circuit applied to intelligent management of photovoltaic module and starting method thereof | |
| CN108054998A (en) | A kind of optimizer, photovoltaic generating system and photovoltaic generation control method | |
| CN202886481U (en) | Capacitor capacity detection circuit of solar energy inverter | |
| CN201994717U (en) | Control device for supplying power to breaker control units | |
| CN207968420U (en) | A kind of optimizer and photovoltaic generating system | |
| CN114865685A (en) | Quick turn-off system and control method thereof | |
| CN108899926B (en) | Photovoltaic off-grid and grid-connected energy storage inverter | |
| CN202353305U (en) | Solar energy and commercial power complementation controller | |
| CN115663907B (en) | Photovoltaic device and power generation system based on double-working-mode ASIC chip control safety | |
| CN101119085A (en) | PWM solar power control module of PWM solar controller | |
| CN204597597U (en) | A kind of domestic solar electric power system | |
| CN201934302U (en) | Self-protective water pump | |
| CN203261257U (en) | Solar photovoltaic power generation single-phase grid-connected inverter | |
| CN202759279U (en) | Household hybrid power supply management system | |
| CN114825435A (en) | Photovoltaic system, starting method of inverter and light storage system | |
| CN114024291A (en) | Multi-control component-level rapid shutoff device | |
| CN113690939A (en) | Light storage all-in-one machine and control method thereof | |
| CN203761058U (en) | Solar DC grid-connected generation DC-DC special-purpose control device of communication base station |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: 518000 3612e27, building a, Xinghe century, No. 3069, CaiTian Road, Gangxia community, Futian street, Futian District, Shenzhen, Guangdong Province Patentee after: Shenzhen Zhongxu new energy Co.,Ltd. Address before: 510000 room 2814, 27 Shuiyin erheng Road, Yuexiu District, Guangzhou City, Guangdong Province Patentee before: Guangzhou Zhongxu new energy Co.,Ltd. |
|
| CP03 | Change of name, title or address |