CN117081358A - Single-phase cascading photovoltaic inverter and processing technology thereof - Google Patents
Single-phase cascading photovoltaic inverter and processing technology thereof Download PDFInfo
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- CN117081358A CN117081358A CN202311289719.7A CN202311289719A CN117081358A CN 117081358 A CN117081358 A CN 117081358A CN 202311289719 A CN202311289719 A CN 202311289719A CN 117081358 A CN117081358 A CN 117081358A
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- 238000012545 processing Methods 0.000 title abstract description 7
- 238000005516 engineering process Methods 0.000 title abstract description 4
- 230000017525 heat dissipation Effects 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 26
- 238000004080 punching Methods 0.000 claims abstract description 17
- 239000013307 optical fiber Substances 0.000 claims abstract description 13
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 8
- 239000010959 steel Substances 0.000 claims abstract description 8
- 238000011900 installation process Methods 0.000 claims abstract description 6
- 238000003466 welding Methods 0.000 claims abstract description 4
- 238000001125 extrusion Methods 0.000 claims description 24
- 241001522296 Erithacus rubecula Species 0.000 claims description 17
- 230000007246 mechanism Effects 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 10
- 239000003990 capacitor Substances 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims 2
- 238000009434 installation Methods 0.000 description 19
- 238000005520 cutting process Methods 0.000 description 8
- 238000003754 machining Methods 0.000 description 6
- 238000010248 power generation Methods 0.000 description 5
- 238000004422 calculation algorithm Methods 0.000 description 4
- 239000011265 semifinished product Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000011324 bead Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 210000002421 cell wall Anatomy 0.000 description 1
- 238000005094 computer simulation Methods 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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- 238000004146 energy storage Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
- H02M1/007—Plural converter units in cascade
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/003—Constructional details, e.g. physical layout, assembly, wiring or busbar connections
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K5/00—Casings, cabinets or drawers for electric apparatus
- H05K5/02—Details
- H05K5/0213—Venting apertures; Constructional details thereof
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2089—Modifications to facilitate cooling, ventilating, or heating for power electronics, e.g. for inverters for controlling motor
-
- 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
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses a single-phase cascading photovoltaic inverter which comprises a plurality of photovoltaic inverters connected in parallel, wherein a host computer circulation control method of the photovoltaic inverter adopts a mode of less intervention photovoltaic. The invention also discloses a single-phase cascading photovoltaic inverter which comprises a plurality of photovoltaic inverters connected in parallel, wherein each photovoltaic inverter comprises a shell, and a slot for radiating or accommodating an optical fiber sensor is formed in the surface of the shell; an inverter assembly is installed in the shell, and a netlike heat dissipation part is arranged on the shell. The invention also discloses a processing technology of the single-phase cascade photovoltaic inverter, which comprises the following processing steps in sequence: welding the steel plates and the steel bars into a semi-finished shell of the photovoltaic inverter; punching a slot and a netlike heat dissipation part on the outer surface of the shell; mounting the inverter assembly to the housing; the protrusions are propped against the grooves or the net-shaped heat dissipation parts in the installation process so as to form heat dissipation holes on the groove walls of the grooves or enlarge the openings of the net-shaped heat dissipation parts. The invention reduces the intervention acquisition frequency.
Description
Technical Field
The invention relates to a circuit device or system for power supply or distribution and an electric energy storage system, in particular to a single-phase cascading photovoltaic inverter and a processing technology thereof.
Background
A photovoltaic inverter (PV inverter or solar inverter) may convert a variable dc voltage generated by a Photovoltaic (PV) solar panel into a mains frequency AC inverter, which may be fed back to a commercial power transmission system or used by an off-grid.
Luo Chaoxu paper published in computer simulation 2023-06-06, a single-phase cascaded photovoltaic inverter decentralized control strategy mentions that: by improving the traditional droop control expression, the actual power output by each photovoltaic unit is tracked to the maximum power point power, and the voltage amplitude is proportional to the maximum active power, so that the frequency and the phase of the output voltage of each unit are self-synchronous and do not need to be communicated, and the output voltage amplitude is adjustable and proportional to the actual power capacity of the unit. In addition, in an actual photovoltaic power generation system, the power generation capacity or capacity of each inverter is not consistent under the influence of different conditions such as illumination, temperature, serial-parallel quantity of photovoltaic modules and the like.
Patent publication number CN 105356497B: a host machine round-robin control method of parallel photovoltaic inverter collects the voltage Upv of a photovoltaic pole plate; judging whether the voltage of the photovoltaic pole plate is larger than or equal to the starting voltage Ustart of the inverter or not, if the voltage Upv of the photovoltaic pole plate is smaller than the starting voltage Ustart of the inverter, each photovoltaic inverter respectively reads the previous cycle round robin value R (k-1), the current cycle round robin value R (k) makes R (k) =R (k-1), calculates the state value of the photovoltaic inverter, compares each photovoltaic inverter with the state values of other photovoltaic inverters respectively, and judges whether the state value of each photovoltaic inverter is larger than the state values of the other photovoltaic inverters or not, if so, the photovoltaic inverter operates in a host mode, and if not, the photovoltaic inverter operates in a slave mode. And from the prior art it is known: in an actual photovoltaic power generation system, the power generation capacity or capacity of each inverter is not consistent under the influence of different conditions such as illumination, temperature, serial-parallel quantity of photovoltaic modules and the like. This is another reason why in the patent publication CN105356497B, the voltage of the photovoltaic plate is directly collected; in the patent with publication number CN105356497B, the voltage of the photovoltaic electrode plate needs to be collected frequently, and the frequent collection (intervention) of the whole system has a certain influence on the system.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a single-phase cascading photovoltaic inverter, the photovoltaic pole plate voltage is only collected in each of the first N round-robin periods, the photovoltaic pole plate voltage is not collected when a host round-robin control method of the photovoltaic inverter is carried out after an algorithm relation is established, the intervention collection frequency is reduced, and the influence on a system is reduced.
In order to achieve the above purpose, the technical scheme of the invention is to design a single-phase cascading photovoltaic inverter, which comprises a plurality of photovoltaic inverters connected in parallel, wherein a host computer round-robin control method of the photovoltaic inverter adopts a mode of less intervention in a photovoltaic system, and the host computer round-robin control method comprises the following steps:
collecting the temperature and illuminance of the photovoltaic pole plate in each round-robin period, and calculating the voltage of the photovoltaic pole plate in the corresponding round-robin period;
the calculation process of the voltage of the photovoltaic polar plate comprises the following steps in sequence:
a: continuously collecting the temperature and illuminance values of the photovoltaic pole plate in the first N round-robin periods and uploading the values to establish a photovoltaic pole plate temperature database and an illuminance database of each round-robin period;
b: collecting the photovoltaic pole plate voltage in each of the first N round-robin periods, and establishing the relation between the photovoltaic pole plate voltage and the temperature, illuminance and the round-robin period duration after the photovoltaic pole plate temperature database and the photovoltaic pole plate illuminance database of the round-robin period corresponding to the same photovoltaic pole plate voltage collected in the same round-robin period are called;
wherein N is not less than 3, but N is less than half of the number of all round-robin cycles. And the photovoltaic pole plate voltage is only collected in each of the first N round robin periods, the photovoltaic pole plate voltage is not collected when the main machine round robin control method of the photovoltaic inverter is carried out after the algorithm relation is established, the intervention collection frequency is reduced, and the influence on a system is reduced. The above-mentioned process (i.e. step A, B) of N number of round robin periods may be performed again after a period of round robin as a spot check mode (or correction mode) to tailor the algorithm relationship to make it more practical.
The further technical scheme is that an optical fiber sensor is arranged on the photovoltaic pole plate and used for comprehensively collecting the temperature of the photovoltaic pole plate; the photovoltaic inverter comprises a shell, and a slot for radiating or accommodating the optical fiber sensor is formed in the surface of the shell. A plurality of heat dissipation holes are arranged on the grooved wall of the shell surface; the grooving on the surface of the shell is used as a structure for accommodating and installing the optical fibers and is also used as a structure for radiating the inverter, and the design of one structure plays two roles.
The further technical scheme is that whether the calculated voltage of the photovoltaic polar plate is larger than or equal to the starting voltage of the inverter is judged;
if the voltage of the photovoltaic pole plate is larger than the starting voltage of the inverter, each photovoltaic inverter respectively acquires a previous cycle round robin value R (k-1), and makes the current cycle round robin value R (k) =R (k-1); then, calculating a state value of one photovoltaic inverter in the parallel photovoltaic inverters;
acquiring state values of a photovoltaic inverter and other photovoltaic inverters in the parallel photovoltaic inverter, judging whether the state value of the photovoltaic inverter is the maximum, if so, judging whether the state value of the photovoltaic inverter is the same as the state values of other photovoltaic inverters in the parallel photovoltaic inverter;
if the state values are not the same, the photovoltaic inverter runs in a host mode, otherwise, the accumulated grid-connected time length of the photovoltaic inverter in the past n days recorded by the photovoltaic inverter is read and compared with other photovoltaic inverters in the parallel photovoltaic inverter;
if the grid-connected duration of the photovoltaic inverter is the minimum value, making R (k ')=R (k), changing the current cycle round-robin value R (k) into R (k')+ (the IP address/N of the photovoltaic inverter), and returning to the step of calculating the state value of one photovoltaic inverter in the parallel photovoltaic inverters; otherwise, the photovoltaic inverter operates in a slave mode. Judging whether the calculated voltage of the photovoltaic pole plate is larger than or equal to the starting voltage of the inverter; if the voltage of the photovoltaic pole plate is smaller than the starting voltage of the inverter, returning to the steps of collecting temperature illuminance and calculating the voltage of the photovoltaic pole plate, otherwise, entering the next step: each photovoltaic inverter respectively acquires a previous cycle round robin value R (k-1), and makes the current cycle round robin value R (k) =R (k-1); then, calculating a state value of a photovoltaic inverter in the parallel photovoltaic inverter, wherein the state value= (running state a1) + (fault state a2) + (current cycle round robin value a3) + (master-slave value A4), wherein A1 is a first weight, A2 is a second weight, A3 is a third weight, A4 is a fourth weight, and a1 > 2 (a2+a3) +a4, a2 > (2×a3) +a4, and a3 > A4; obtaining the state values of the photovoltaic inverter and other photovoltaic inverters in the parallel photovoltaic inverter, judging whether the state value of the photovoltaic inverter is the largest, if the state value of the photovoltaic inverter is the largest, entering the next step (judging whether the state value of the photovoltaic inverter is the same as the state value of the other photovoltaic inverters in the parallel photovoltaic inverter, if the state value is not the same, the photovoltaic inverter operates in a host mode, otherwise, entering the next step { read the accumulated grid-connected time length of the photovoltaic inverter in the past N days recorded by the photovoltaic inverter, and compare with the other photovoltaic inverters in the parallel photovoltaic inverter, if the grid-connected time length of the photovoltaic inverter is the smallest, entering the next step (R (k')=R (k)), changing the current cycle round-robin value R (k) into the IP address/N of the photovoltaic inverter (the photovoltaic inverter), and otherwise, entering the photovoltaic inverter from the parallel photovoltaic inverter mode.
The invention also provides a technical scheme that the single-phase cascading photovoltaic inverter comprises a plurality of photovoltaic inverters which are connected in parallel, wherein each photovoltaic inverter comprises a shell, and a slot for radiating or accommodating an optical fiber sensor is arranged on the surface of the shell; an inverter assembly is installed in the shell, and a netlike heat dissipation part is arranged on the shell. The surface of part of the shell is provided with a netlike heat dissipation part which is generally arranged at the lower half parts of the top surface and the side surface; the bottom surface does not generally take the form of a mesh-like heat dissipation portion, but is provided with a plurality of through holes for bottom heat dissipation of the inverter.
The further technical scheme is that the inverter component comprises a circuit board, a fuse, a power switch tube, an inductor, a relay and a capacitor plate;
the mounting seat of the circuit board or the capacitor board for being mounted on the shell is provided with a bulge, and the position of the bulge corresponds to the slotting or the netlike heat dissipation part. The end of the bulge is smooth and hemispherical, so that the exposed bulge after the installation is finished can be prevented from stabbing workers or damaging surrounding parts. After the inverter is assembled, when the photovoltaic system is formed by the inverter and the photovoltaic panel, the optical fiber sensor is placed in a slot of the inverter shell.
The technical scheme provided by the invention is that the process for processing the single-phase cascade photovoltaic inverter comprises the following process steps in sequence:
s1: welding the steel plates and the steel bars into a semi-finished shell of the photovoltaic inverter; stamping a netlike heat dissipation part on the outer surface of the semi-finished shell; extruding a slot on the outer surface of the semi-finished shell by adopting an extruding mechanism;
s2: mounting the inverter assembly to the housing; the bulge is propped against the slotting or the netlike radiating part in the installation process so as to form radiating holes or enlarge the opening of the netlike radiating part on the slot wall of the slotting;
wherein the mesh-shaped heat dissipation part is punched on the surface of the shell by a punching machine. And stamping the rudiment of the net-shaped heat dissipation part on the outer surface of the semi-finished shell, extruding a slot on the outer surface of the semi-finished shell, and further forming an opening of the net-shaped heat dissipation part and a slot wall penetrating through the slot in a propping way to form a heat dissipation hole on the slot wall during subsequent installation.
The size of the punch head of the punching machine is smaller than the opening of the net-shaped heat dissipation part; the extrusion mechanism comprises a hydraulic cylinder, the exposed end of a piston rod of the hydraulic cylinder is fixedly connected with a profiling extrusion die, the profiling extrusion die is matched with the grooving shape, and a plurality of salient points for forming heat dissipation holes on the groove wall of the grooving are arranged on the surface of the profiling extrusion die. The size of the punch of the punching machine is smaller than the opening of the net-shaped radiating part, so that high punching precision is not required during punching, high acquisition cost caused by high precision requirement of the punching machine is reduced, the net-shaped radiating part is firstly preliminarily machined, the radiating opening of the net-shaped radiating part is further enlarged by the installation process, the final installation procedure in the machining process of the whole inverter is changed into the machining opening procedure (precisely, further machining opening) at the same time, the cost is reduced, the requirement is met, and the efficiency is improved to a certain extent due to the fact that the size of the opening which is preliminarily machined is not large, and the energy consumption is low. The specific flaring process is that a little more is ejected outwards during installation, namely, the bulge on the installation seat is ejected outwards (the ejection distance is longer than the exposed part of the bulge after the actual installation) just at the beginning of installation, so that the bulge is not completely ejected at the opening after the part is installed later (namely, the opening is tightly abutted by the side surface of the bulge so that the opening is in a basically closed state), and the heat dissipation opening can dissipate heat.
And extruding a slot on the outer surface of the semi-finished shell by adopting an extruding mechanism, wherein a profiling extruding die of the extruding mechanism is provided with a convex point for preliminarily forming a radiating hole on the slot wall of the slot, and the size of the convex point is also smaller than the size of the radiating hole on the slot wall of the final slot. Because it is the pneumatic cylinder extrusion, probably only extrude the part that inwards protrudes into the casing through the bump on the grooved cell wall, the aforesaid protruding part is outwards topped with forming the louvre through the protruding of setting up on the mount pad again when installing (can set up the tip of extrusion die's bump into spike form, so be easier to form preliminary louvre-the hole of size less than final louvre when extrusion, and set up very thin arch in bellied side in order to play the effect of blade, so that not only form small-size hole as the basis when follow-up quilt is topped/flaring when extrusion, still form the breach at the edge of small-size hole in order to follow-up mount pad's arch is outwards topped when installing better reaming). The sides of the punch press are provided with very thin projections (like the cutting edges, the cutting edge projections are provided with three or four, are arranged on the sides of the punch and are integrally formed with the punch around the punch annular array) for forming a split in the circumferential direction of the small hole when the surface of the shell is punched into the small hole so that the projections on the mounting seat are better reamed (or flared) when being propped outwards during mounting. The protruding structure on the mounting seat can be used for assisting in fixing and stabilizing the mounting seat (although the mounting seat is mainly connected with the shell through other structural members during mounting, such as a bump clamping groove in a matched mode, the bump is generally arranged on the mounting seat, the clamping groove is generally arranged on the inner side wall of the shell), and the protruding structure on the mounting seat plays two roles.
The invention has the advantages and beneficial effects that: and the photovoltaic pole plate voltage is only collected in each of the first N round robin periods, the photovoltaic pole plate voltage is not collected when the main machine round robin control method of the photovoltaic inverter is carried out after the algorithm relation is established, the intervention collection frequency is reduced, and the influence on a system is reduced.
A plurality of heat dissipation holes are arranged on the grooved wall of the shell surface; the grooving on the surface of the shell is used as a structure for accommodating and installing the optical fibers and is also used as a structure for radiating the inverter, and the design of one structure plays two roles.
The size of the punch of the punching machine is smaller than the opening of the net-shaped radiating part, so that high punching precision is not required during punching, high acquisition cost caused by high precision requirement of the punching machine is reduced, the net-shaped radiating part is firstly preliminarily machined, the radiating opening of the net-shaped radiating part is further enlarged by the installation process, the final installation procedure in the machining process of the whole inverter is changed into the machining opening procedure (precisely, further machining opening) at the same time, the cost is reduced, the requirement is met, and the efficiency is improved to a certain extent due to the fact that the size of the opening which is preliminarily machined is not large, and the energy consumption is low.
The sides of the punch press are provided with very thin projections (like the cutting edges, the cutting edge projections are provided with three or four, are arranged on the sides of the punch and are integrally formed with the punch around the punch annular array) for forming a split in the circumferential direction of the small hole when the surface of the shell is punched into the small hole so that the projections on the mounting seat are better reamed (or flared) when being propped outwards during mounting.
Drawings
FIG. 1 is a schematic diagram of a single-phase cascaded photovoltaic inverter of an embodiment of the present invention;
FIG. 2 is a left side view of FIG. 1;
FIG. 3 is an enlarged schematic view of portion A of FIG. 2;
FIG. 4 is an enlarged schematic view of portion B of FIG. 2;
FIG. 5 is an enlarged schematic view of portion C of FIG. 1;
FIG. 6 is an enlarged schematic view of portion D of FIG. 1;
FIG. 7 is an enlarged schematic view of portion E of FIG. 6;
FIG. 8 is a right side view of the housing of FIG. 1 with the housing frame removed;
FIG. 9 is an enlarged schematic view of portion G of FIG. 8;
FIG. 10 is a schematic view of a pressing mechanism for pressing a slot into the surface of the housing of FIG. 2;
FIG. 11 is an enlarged schematic view of portion F of FIG. 10;
FIG. 12 is an enlarged schematic view of the boss portion of FIG. 11;
fig. 13 is a schematic structural view of a punch portion of the press according to the present invention;
fig. 14 is a schematic diagram of a single-phase cascaded photovoltaic inverter of the second embodiment of the present invention applied to a photovoltaic system;
fig. 15 is a schematic view showing a state of a bump on a mount of a single-phase cascaded photovoltaic inverter in the third embodiment of the present invention at the initial stage of the mounting;
FIG. 16 is a schematic view of the boss of FIG. 15 after the boss has been over-reamed or flared;
FIG. 17 is a schematic view of the push-in tab of FIG. 16;
FIG. 18 is a schematic view of FIG. 17 with the protrusions removed;
fig. 19 is a schematic view of the connecting cord, stop and magnet portion of fig. 18.
In the figure: 1. a housing; 2. slotting; 3. a heat radiation hole; 4. a mesh-shaped heat dissipation portion; 5. a through hole; 6. an inverter assembly; 7. a mounting base; 8. a protrusion; 9. a hydraulic cylinder; 10. profiling extrusion die; 11. a bump; 12. a cutting edge; 13. a split; 14. a punch; 15. a fastening bolt; 16. an abutment block; 17. a circular groove-like member; 18. a connecting rope; 19. a stop block; 20. a receiving groove; 21. a magnetic stripe; 22. and (3) a magnet.
Detailed Description
The following describes the embodiments of the present invention further with reference to the drawings and examples. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
Embodiment one:
as shown in fig. 1 to 13 (for convenience of illustration, the front panel and the right panel of the housing are not shown in fig. 1), the invention is a single-phase cascading photovoltaic inverter, which comprises a plurality of photovoltaic inverters connected in parallel, wherein a host circulation control method of the photovoltaic inverter adopts a less-intervention photovoltaic mode, and the host circulation control method comprises the following steps:
collecting the temperature and illuminance of the photovoltaic pole plate in each round-robin period, and calculating the voltage of the photovoltaic pole plate in the corresponding round-robin period;
the calculation process of the voltage of the photovoltaic polar plate comprises the following steps in sequence:
a: continuously collecting the temperature and illuminance values of the photovoltaic pole plate in the first N round-robin periods and uploading the values to establish a photovoltaic pole plate temperature database and an illuminance database of each round-robin period;
b: collecting the photovoltaic pole plate voltage in each of the first N round-robin periods, and establishing the relation between the photovoltaic pole plate voltage and the temperature, illuminance and the round-robin period duration after the photovoltaic pole plate temperature database and the photovoltaic pole plate illuminance database of the round-robin period corresponding to the same photovoltaic pole plate voltage collected in the same round-robin period are called;
wherein N is not less than 3, but N is less than half of the number of all round-robin cycles. An optical fiber sensor is arranged on the photovoltaic pole plate and used for comprehensively collecting the temperature of the photovoltaic pole plate; the photovoltaic inverter comprises a shell 1, and a slot 2 for radiating or accommodating the optical fiber sensor is arranged on the surface of the shell 1. A plurality of heat dissipation holes 3 are arranged on the groove wall of the groove 2 on the surface of the shell 1; judging whether the calculated voltage of the photovoltaic pole plate is larger than or equal to the starting voltage of the inverter;
if the voltage of the photovoltaic pole plate is larger than the starting voltage of the inverter, each photovoltaic inverter respectively acquires a previous cycle round robin value R (k-1), and makes the current cycle round robin value R (k) =R (k-1); then, calculating a state value of one photovoltaic inverter in the parallel photovoltaic inverters;
acquiring state values of a photovoltaic inverter and other photovoltaic inverters in the parallel photovoltaic inverter, judging whether the state value of the photovoltaic inverter is the maximum, if so, judging whether the state value of the photovoltaic inverter is the same as the state values of other photovoltaic inverters in the parallel photovoltaic inverter;
if the state values are not the same, the photovoltaic inverter runs in a host mode, otherwise, the accumulated grid-connected time length of the photovoltaic inverter in the past n days recorded by the photovoltaic inverter is read and compared with other photovoltaic inverters in the parallel photovoltaic inverter;
if the grid-connected duration of the photovoltaic inverter is the minimum value, making R (k ')=R (k), changing the current cycle round-robin value R (k) into R (k')+ (the IP address/N of the photovoltaic inverter), and returning to the step of calculating the state value of one photovoltaic inverter in the parallel photovoltaic inverters; otherwise, the photovoltaic inverter operates in a slave mode.
The single-phase cascading photovoltaic inverter comprises a plurality of photovoltaic inverters which are connected in parallel, wherein each photovoltaic inverter comprises a shell 1, and a slot 2 for radiating heat or accommodating an optical fiber sensor is arranged on the surface of the shell 1; an inverter assembly 6 is installed in the housing 1, and a mesh-shaped heat dissipation portion 4 is provided on the housing 1. A part of the surface of the shell 1 is provided with a netlike heat dissipation part 4 which is generally arranged at the lower half parts of the top surface and the side surface; the bottom surface is generally not in the form of a mesh-like heat dissipating portion 4, but several through holes 5 are provided in the bottom surface for bottom heat dissipation of the inverter. The inverter assembly 6 comprises a circuit board, a fuse, a power switch tube, an inductor, a relay and a capacitor plate; the mounting seat 7 of the circuit board or the capacitor board for being mounted on the shell 1 is provided with a bulge 8, and the position of the bulge 8 corresponds to the slot 2 or the netlike heat dissipation part 4. The end of the protrusion 8 is in a rounded hemispherical shape,
the process for processing the single-phase cascade photovoltaic inverter comprises the following process steps in sequence:
s1: welding the steel plates and the steel bars into a semi-finished product of a shell 1 of the photovoltaic inverter; punching a net-shaped heat dissipation part 4 on the outer surface of the shell 1; extruding a slot 2 on the outer surface of the shell 1 by adopting an extruding mechanism;
s2: mounting the inverter assembly 6 on the housing 1; the protrusion 8 is propped against the slot 2 or the net-shaped heat dissipation part 4 in the installation process to form a heat dissipation hole 3 or enlarge the opening of the net-shaped heat dissipation part 4 on the slot wall of the slot 2;
wherein the mesh-like heat dissipation portion 4 is punched on the surface of the case 1 by a punching machine.
In addition, in the case of punching, the punch 14 with high precision is used for the mesh heat dissipation portion 4 which is not attached to the mount 7, and the punch 14 with small size is used for the punch 14 corresponding to the mesh heat dissipation portion 4 corresponding to the attachment position of the mount 7, so that the abrasion of the punch 14 with high precision is reduced and the service life of such punch 14 is reduced. And the bump 11 on the extrusion die, which does not correspond to the heat dissipation hole 3 on the portion of the slot 2 where the mount 7 is attached, is also correspondingly sized to be consistent with the size of the final heat dissipation hole 3. The outer surface of the semi-finished product of the shell 1 is punched with the rudiment of the netlike heat dissipation part 4, the outer surface of the semi-finished product of the shell 1 is extruded with the groove 2, and the opening of the netlike heat dissipation part 4 and the groove wall penetrating through the groove 2 are further formed during the subsequent installation to form the heat dissipation hole 3 on the groove wall. The size of the punch 14 of the punching machine is smaller than the opening of the mesh-shaped heat radiating portion 4; the extrusion mechanism comprises a hydraulic cylinder 9, the exposed end of a piston rod of the hydraulic cylinder 9 is fixedly connected with a profiling extrusion die 10, the profiling extrusion die 10 is matched with the shape of the slot 2, and a plurality of salient points 11 used for forming the heat dissipation holes 3 on the wall of the slot 2 are arranged on the surface of the profiling extrusion die 10. During installation, more protrusions are outwards ejected, namely the protrusions 8 on the installation seat 7 are outwards ejected (the ejection distance is longer than the exposed part of the protrusions 8 after the installation is actually carried out) at the beginning of installation, so that the protrusions 8 are not completely ejected at the opening after the parts are installed later (namely the opening is tightly abutted by the side surfaces of the protrusions 8 so that the opening is in a basically closed state), and the heat dissipation opening can dissipate heat. The outer surface of the semi-finished product of the shell 1 is extruded to form a slot 2 by adopting an extrusion mechanism, a profiling extrusion die 10 of the extrusion mechanism is provided with a convex point 11 for preliminarily forming a radiating hole 3 on the wall of the slot 2, and the size of the convex point 11 is also smaller than the size of the radiating hole 3 on the wall of the slot 2. The ends of the protruding points 11 of the extrusion die are arranged in a spike shape, so that a preliminary heat dissipation hole 3 is easier to form during extrusion, the size of the hole is smaller than that of the final heat dissipation hole 3, and a thin protrusion is arranged on the side surface of the protrusion 8 to play a role of a cutting edge 12, so that a small-size hole is formed as a basis for the subsequent propped/flared operation during extrusion, and a split 13 is formed at the edge of the small-size hole, so that the protrusion 8 on the subsequent mounting seat 7 is better reamed when propped outwards during mounting; the sides of the punch 14 of the press are provided with very thin projections (like the cutting edges 12, four projections of the cutting edges 12, arranged in an annular array around the punch 14 on the sides of the punch 14 integrally formed with the punch 14) for forming slits 13 also in the circumferential direction of the apertures when punching apertures in the surface of the housing 1 for better reaming (or flaring) of the projections 8 on the mounting base 7 when mounted to the outside.
Embodiment two:
the schematic diagram of the single-phase cascading photovoltaic inverter applied to the photovoltaic system is shown in fig. 14, and the photovoltaic power generation system consists of a solar cell array providing about 380VDC steady-state output, an IGBT-based full-bridge single-phase cascading photovoltaic inverter and an LCL output filter connected to a 230Vrms and 50Hz single-phase power supply.
Embodiment III:
the difference from the first embodiment is that, as shown in fig. 15 to 19, the protrusion 8 is composed of two symmetrically arranged parts, the two parts are combined to form the protrusion 8 and the two parts are fastened and connected by the fastening bolt 15; the fixed piece 16 that is used for supporting when protruding 8 outwards pushes up that is equipped with in position department that corresponds with protruding position on the mount pad 7 is supported to the piece 16, protruding its tip towards the mount pad sets up the internal bead, it is towards protruding tip cover to support the piece 16 and establish circular slot form part 17, circular slot form part 17 links to each other with dog 19 through connecting rope 18, dog length is longer, the width is shorter, the mount pad is equipped with holding tank 20 towards protruding internal bead's position department, the holding tank is rectangular slot form and its degree of depth and the length phase-match of dog, and the notch size of holding tank is greater than the width and the thickness of dog so that the dog gets into.
The protrusions are arranged as follows: after the installation is finished, the installation is pulled outwards, the protrusion is pushed inwards again to enable the position of the protrusion to be closer to the installation seat than the position of the protrusion, the protrusion can be prevented from being exposed after the installation is finished, and the problem that the installation stability of the installation seat is affected due to the fact that the protrusion is touched by a person outside the shell is avoided.
The stop block is vertically arranged (namely, the stop block 19 is vertically arranged in the length direction), two parts of the bulge are inserted into a gap between the stop block and the round groove-shaped part 17 (of course, the thickness dimension of the round groove-shaped part 17 plus the width dimension of the stop block are smaller than the height dimension of the abutting block 16), then the mounting seat is outwards jacked by the bulge reaming or flaring during mounting, then the bulge is outwards pulled after the mounting seat is mounted, the bulge is inwards curled, the round groove-shaped part 17 is driven to outwards by the bulge, the stop block is changed into a horizontal state from a vertical state due to the action of the connecting rope 18, and the bulge is pushed inwards again, so that the bulge is prevented from being exposed more inwards than the initial position (in order to better realize the scheme, a magnetic strip 21 is also arranged at the side surface of the stop block, a cavity is arranged at the position close to the side surface of the abutting block, and the magnet 22 matched with the magnetic strip is arranged in the cavity so that the stop block is horizontally moved so as to be convenient to enter the accommodating groove during the process of outwards pulling and inwards pushing of the bulge).
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the scope of the invention.
Claims (7)
1. The single-phase cascading photovoltaic inverter is characterized by comprising a plurality of photovoltaic inverters which are connected in parallel, wherein a main machine circulation control method of the photovoltaic inverter adopts a mode of a photovoltaic system with less intervention, and the main machine circulation control method comprises the following steps:
collecting the temperature and illuminance of the photovoltaic pole plate in each round-robin period, and calculating the voltage of the photovoltaic pole plate in the corresponding round-robin period;
the calculation process of the voltage of the photovoltaic polar plate comprises the following steps in sequence:
a: continuously collecting the temperature and illuminance values of the photovoltaic pole plate in the first N round-robin periods and uploading the values to establish a photovoltaic pole plate temperature database and an illuminance database of each round-robin period;
b: collecting the photovoltaic pole plate voltage in each of the first N round-robin periods, and establishing the relation between the photovoltaic pole plate voltage and the temperature, illuminance and the round-robin period duration after the photovoltaic pole plate temperature database and the photovoltaic pole plate illuminance database of the round-robin period corresponding to the same photovoltaic pole plate voltage collected in the same round-robin period are called;
wherein N is not less than 3, but N is less than half of the number of all round-robin cycles.
2. The single-phase cascading photovoltaic inverter according to claim 1, wherein an optical fiber sensor is arranged on the photovoltaic pole plate for comprehensively collecting the temperature of the photovoltaic pole plate; the photovoltaic inverter comprises a shell, and a slot for radiating or accommodating the optical fiber sensor is formed in the surface of the shell.
3. A single-phase cascaded photovoltaic inverter according to claim 1 or 2, characterized in that it is determined whether the calculated photovoltaic panel voltage is equal to or higher than the inverter starting voltage;
if the voltage of the photovoltaic pole plate is larger than the starting voltage of the inverter, each photovoltaic inverter respectively acquires a previous cycle round robin value R (k-1), and makes the current cycle round robin value R (k) =R (k-1); then, calculating a state value of one photovoltaic inverter in the parallel photovoltaic inverters;
acquiring state values of a photovoltaic inverter and other photovoltaic inverters in the parallel photovoltaic inverter, judging whether the state value of the photovoltaic inverter is the maximum, if so, judging whether the state value of the photovoltaic inverter is the same as the state values of other photovoltaic inverters in the parallel photovoltaic inverter;
if the state values are not the same, the photovoltaic inverter runs in a host mode, otherwise, the accumulated grid-connected time length of the photovoltaic inverter in the past n days recorded by the photovoltaic inverter is read and compared with other photovoltaic inverters in the parallel photovoltaic inverter;
if the grid-connected duration of the photovoltaic inverter is the minimum value, making R (k ')=R (k), changing the current cycle round-robin value R (k) into R (k')+ (the IP address/N of the photovoltaic inverter), and returning to the step of calculating the state value of one photovoltaic inverter in the parallel photovoltaic inverters; otherwise, the photovoltaic inverter operates in a slave mode.
4. The single-phase cascading photovoltaic inverter is characterized by comprising a plurality of photovoltaic inverters which are connected in parallel, wherein each photovoltaic inverter comprises a shell, and a slot for radiating heat or accommodating an optical fiber sensor is formed in the surface of the shell; an inverter assembly is installed in the shell, and a netlike heat dissipation part is arranged on the shell.
5. The single-phase cascaded photovoltaic inverter of claim 4, wherein the inverter assembly comprises a circuit board, a fuse, a power switching tube, an inductor, a relay, and a capacitor plate;
the mounting seat of the circuit board or the capacitor board for being mounted on the shell is provided with a bulge, and the position of the bulge corresponds to the slotting or the netlike heat dissipation part.
6. A process for manufacturing a single-phase cascaded photovoltaic inverter according to claim 5, comprising the following process steps, carried out in sequence:
s1: welding the steel plates and the steel bars into a semi-finished shell of the photovoltaic inverter; stamping a netlike heat dissipation part on the outer surface of the semi-finished shell; extruding a slot on the outer surface of the semi-finished shell by adopting an extruding mechanism;
s2: mounting the inverter assembly to the housing; the bulge is propped against the slotting or the netlike radiating part in the installation process so as to form radiating holes or enlarge the opening of the netlike radiating part on the slot wall of the slotting;
wherein the mesh-shaped heat dissipation part is punched on the surface of the shell by a punching machine.
7. The process for manufacturing a single-phase cascade photovoltaic inverter according to claim 6, wherein the punch of the punch has a size smaller than the opening of the mesh-shaped heat dissipation portion; the extrusion mechanism comprises a hydraulic cylinder, the exposed end of a piston rod of the hydraulic cylinder is fixedly connected with a profiling extrusion die, the profiling extrusion die is matched with the grooving shape, and a plurality of salient points for forming heat dissipation holes on the groove wall of the grooving are arranged on the surface of the profiling extrusion die.
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