CN212811632U - Photovoltaic inverter - Google Patents
Photovoltaic inverter Download PDFInfo
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- CN212811632U CN212811632U CN202021550590.2U CN202021550590U CN212811632U CN 212811632 U CN212811632 U CN 212811632U CN 202021550590 U CN202021550590 U CN 202021550590U CN 212811632 U CN212811632 U CN 212811632U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The utility model discloses a photovoltaic inverter, which comprises an inverter unit and a frame breaker which are sequentially connected between a direct current input side and an alternating current output side; the frame circuit breaker is externally connected with a circuit breaker self-connection power supply, and the circuit breaker self-connection power supply supplies power to the frame circuit breaker, wherein the circuit breaker self-connection power supply comprises a self-connection direct current power supply and a self-connection alternating current power supply; the frame circuit breaker comprises a closing electromagnet, a shunt release and an undervoltage release; the self-connecting direct current power supply is respectively connected with the closing electromagnet and the shunt release, and the self-connecting alternating current power supply is connected with the undervoltage release. The photovoltaic inverter grid-connected operation can be realized without a contactor or through a frame breaker, the damage of the inverter caused by the misoperation of the traditional breaker is avoided, the manufacturing cost of the photovoltaic inverter is reduced, the size of the high-power photovoltaic inverter is reduced, the power density of the photovoltaic inverter is improved, and the stable operation of the photovoltaic inverter is ensured.
Description
Technical Field
The embodiment of the utility model provides a relate to inverter technical field, especially relate to a photovoltaic inverter.
Background
With the subsidy of the domestic photovoltaic new energy industry, products of various domestic inverter suppliers in various power sections are gradually transformed to cost and quality, cost control can be performed on small inverters in a relatively simple mode, and for large inverters, particularly high-voltage 1500VDC high-power inverters, the cost is the highest pressure in order to ensure the quality of the inverters.
The main devices of the inverter comprise a direct current input switch, an IGBT module, a BUS capacitor module, an inverter inductor, a filter capacitor, an alternating current output contactor and an alternating current output circuit breaker, and the cost is reduced by the method of viewing from the main power device: 1. the cost reduction is realized by changing the model of each power device, and the cost reduction is limited by the mode; 2. the direct-current side input circuit breaker is omitted and is concentrated in the direct-current junction box, so that the cost can be saved to a great extent, but the stability of the inverter is sacrificed, and the probability of faults occurring on the direct-current side is high; 3. an alternating current measurement output circuit breaker is omitted, the requirement of an inverter can be met by utilizing the million mechanical lives of contactors, but the purpose of alternating current measurement short circuit or other fault protection of the inverter cannot be met due to the fact that the contactors have no breaking capacity or have limited breaking capacity; 4. an alternating current contactor is omitted, but a long-life alternating current frame breaker can meet the requirement, the cost is saved to the maximum extent by the mode, but the alternating current frame breaker is required to have special performance configuration, and a special control method on software is also required.
As shown in fig. 1, a control method of a conventional grid-connected three-phase inverter is to keep an output ac frame circuit breaker in a closed state, the ac frame circuit breaker is tripped only under the condition of some serious faults, and the ac frame circuit breaker is kept in a closed state under other conditions, and according to the relation between real-time inverter voltage and grid voltage, a contactor is attracted to achieve grid connection when requirements are met. The following aspects are mainly considered for the stability and safety of the composition:
(1) the contactor has the mechanical service life of millions of times to meet the requirements of closing and opening;
(2) when a fault occurs in heavy current operation, the contactor has no breaking capacity, and at the moment, because the contact of the contactor is adhered, the reliable disconnection of the contactor cannot be completely ensured, and the reliable protection needs to be realized by further depending on the disconnection of an alternating current breaker;
(3) when a system power supply fault occurs, the power grid can be disconnected by the contactor, when the output current is large, the contactor cannot be guaranteed to be reliably disconnected, and if the alternating current breaker cannot be timely disconnected, the reverse-flow direct current side of the power grid is caused, power devices such as Insulated Gate Bipolar Transistor (IGBT) and the like are damaged, and a larger fault is caused;
(4) if the disconnection time of the contactor is too long, the contactor cannot timely disconnect the reverse-injection direct-current side of the power grid, and power devices such as an IGBT (insulated gate bipolar translator) and the like are damaged;
aiming at the phenomenon that the contactor or the relay contact is stuck, a plurality of manufacturers select a mode of connecting the contactor or the relay in parallel to ensure the reliability of the existing inverter, but the condition mostly occurs in a low-power or group-series inverter, the mode can not be selected generally for the high-power inverter due to the cost pressure, and the stability and the reliability of the inverter can only be realized through other modes.
SUMMERY OF THE UTILITY MODEL
The utility model provides a photovoltaic inverter has realized not needing the contactor also can realize photovoltaic inverter's the operation of being incorporated into the power networks through the frame circuit breaker, has avoided traditional circuit breaker malfunction to lead to the damage of dc-to-ac converter, has reduced photovoltaic inverter's cost of manufacture, has reduced high-power photovoltaic inverter's volume, has promoted photovoltaic inverter's power density, has ensured photovoltaic inverter's steady operation.
The embodiment of the utility model provides a photovoltaic inverter, photovoltaic inverter includes the contravariant unit and the frame circuit breaker that connect gradually between direct current input side and alternating current output side; the inverter unit is electrically connected with the direct current input side, and the frame circuit breaker is electrically connected with the alternating current output side;
the frame circuit breaker is externally connected with a circuit breaker self-connection power supply, the circuit breaker self-connection power supply supplies power to the frame circuit breaker, and the circuit breaker self-connection power supply comprises a self-connection direct current power supply and a self-connection alternating current power supply;
the frame circuit breaker comprises a closing electromagnet, a shunt release and an undervoltage release; the self-connecting direct-current power supply is respectively connected with the closing electromagnet and the shunt release, and the self-connecting alternating-current power supply is connected with the undervoltage release.
Further, the shunt release comprises a shunt release drive and a shunt coil;
the first end of the shunt tripping drive is connected with the anode of the self-connected direct-current power supply, the second end of the shunt tripping drive is connected with the first end of the shunt coil, and the second end of the shunt coil is connected with the cathode of the self-connected direct-current power supply;
the undervoltage release comprises an undervoltage release drive, an undervoltage coil and a first normally open contact;
the first end of the undervoltage tripping drive is connected with the phase line of the self-connected alternating current power supply, the second end of the undervoltage tripping drive is connected with the first end of the undervoltage coil, and the second end of the undervoltage coil is connected with the neutral line of the self-connected alternating current power supply through a first normally open contact.
Further, the frame circuit breaker further comprises a first power supply switch, a second power supply switch and a remote control button; the first power supply switch is linked with the second power supply switch;
the first power supply switch is arranged between the first normally open contact and a neutral line of the self-connected alternating current power supply;
the first end of the second power supply switch is connected with the phase line which is connected with the alternating current power supply, the second end of the second power supply switch is connected with the first end of the remote control button, and the second end of the remote control button is connected with the first end of the undervoltage coil.
Further, the direct current input side is sequentially connected with a direct current bus, a plurality of normally closed switches and a plurality of photovoltaic panels;
the photovoltaic panel is used for acquiring solar energy and converging the acquired solar energy onto the direct current bus.
Furthermore, a plurality of first Hall sensors and a plurality of fuses are arranged between the direct current bus and the normally closed switch;
each fuse is connected between the positive electrode of one photovoltaic panel and the normally-closed switch; each first Hall sensor is connected between the negative electrode of one photovoltaic panel and the normally closed switch.
Further, a bus capacitor is arranged between the direct current input side and the direct current bus; the positive electrode of the bus capacitor is respectively connected with the positive electrode of the direct current bus and the positive electrode of the direct current input side;
and the cathode of the bus capacitor is respectively connected with the cathode of the direct current bus and the cathode of the direct current input side.
Further, the inverter unit includes a plurality of inverter devices and a plurality of second hall sensors; one of the second hall sensors is disposed between one phase output of the output side of one of the inverter devices and the frame circuit breaker.
Further, the inverter unit further comprises a plurality of inductors and a plurality of capacitors;
one said inductor is disposed between one said second hall sensor and said frame circuit breaker;
the capacitor is arranged between the inductor and the frame circuit breaker and is connected between two phase output lines of the output side of the inverter in parallel.
Further, the inverter unit further comprises a plurality of transformers; the same phase output of the output sides of the inverters is connected with a primary side loop of the same transformer; and a secondary side loop of the mutual inductor is connected with the frame breaker.
Further, the direct current bus is also connected with a first surge protector, and the alternating current output side is also connected with a second surge protector;
the first surge protector is respectively connected with the anode and the cathode of the direct current bus;
the second surge protectors are connected to the three-phase output lines on the ac output side, respectively.
The utility model discloses a photovoltaic inverter, which comprises an inverter unit and a frame breaker which are sequentially connected between a direct current input side and an alternating current output side; the inverter unit is electrically connected with the direct current input side, and the frame circuit breaker is electrically connected with the alternating current output side; the frame circuit breaker is externally connected with a circuit breaker self-connection power supply, and the circuit breaker self-connection power supply supplies power to the frame circuit breaker, wherein the circuit breaker self-connection power supply comprises a self-connection direct current power supply and a self-connection alternating current power supply; the frame circuit breaker comprises a closing electromagnet, a shunt release and an undervoltage release; the self-connecting direct current power supply is respectively connected with the closing electromagnet and the shunt release, and the self-connecting alternating current power supply is connected with the undervoltage release. The photovoltaic inverter grid-connected operation can be realized without a contactor or through a frame breaker, the damage of the inverter caused by the misoperation of the traditional breaker is avoided, the manufacturing cost of the photovoltaic inverter is reduced, the size of the high-power photovoltaic inverter is reduced, the power density of the photovoltaic inverter is improved, and the stable operation of the photovoltaic inverter is ensured.
Drawings
Fig. 1 is a topological diagram of a conventional photovoltaic inverter grid connection provided by an embodiment of the present invention;
fig. 2 is a structural diagram of a photovoltaic inverter according to an embodiment of the present invention;
fig. 3 is a structural diagram of a frame circuit breaker according to an embodiment of the present invention;
fig. 4 is a structural diagram of another photovoltaic inverter according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
It should be noted that the terms "first", "second", and the like in the description and claims of the present invention and the accompanying drawings are used for distinguishing different objects, and are not intended to limit a specific order. The embodiments of the present invention can be implemented individually, and can be implemented by combining each other between the embodiments, and the embodiments of the present invention are not limited to this.
Fig. 2 is a structural diagram of a photovoltaic inverter according to an embodiment of the present invention.
As shown in fig. 2, the photovoltaic inverter includes an inverter unit 20 and a frame breaker 30 connected in sequence between a direct current input side and an alternating current output side; the inverter unit 20 is electrically connected to the dc input side, and the frame breaker 30 is electrically connected to the ac output side.
The frame circuit breaker 30 is externally connected with a circuit breaker self-connection power supply 40, the circuit breaker self-connection power supply 40 supplies power to the frame circuit breaker 30, wherein the circuit breaker self-connection power supply 40 comprises a self-connection direct current power supply Vdc and a self-connection alternating current power supply Vac.
The frame circuit breaker 30 includes a closing electromagnet 31, a shunt release 32, and an undervoltage release 33; the self-connected direct current power supply Vdc is respectively connected with the closing electromagnet 31 and the shunt release 32, and the self-connected alternating current power supply Vac is connected with the undervoltage release 33.
Specifically, for the photovoltaic inverter, a direct current input side of the photovoltaic inverter is sequentially connected with a direct current bus and a plurality of photovoltaic panels, solar energy obtained by the photovoltaic panels is gathered on the direct current bus, the inverter unit 20 is connected with the direct current bus through the direct current input side, the solar energy obtained by the photovoltaic panels is converted into three-phase alternating current, and the three-phase alternating current is transmitted to a power grid from an alternating current output side through the frame circuit breaker 30, so that grid connection of the photovoltaic inverter is achieved.
In the embodiment of the present invention, the frame circuit breaker 30 is provided with a closing electromagnet 31, a shunt release 32 and an undervoltage release 33, in order to prevent the frame circuit breaker 30 from releasing in time when the system power fails, the frame circuit breaker 30 is further externally connected with a circuit breaker self-connection power supply 40, and the circuit breaker self-connection power supply 40 includes a self-connection dc power supply Vdc and a self-connection ac power supply Vac; the shunt release 32 and the undervoltage release 33 are connected with different power supplies, namely, the self-connected direct current power supply Vdc is connected with the shunt release 32, and the self-connected alternating current power supply Vac is connected with the undervoltage release 33, so that the shunt release 32 or the undervoltage release 33 can act in time through the electric energy provided by the external power supply 21 of the circuit breaker when a system power supply fails and the inverter needs to be protected but the frame circuit breaker 30 is not tripped in time, and the frame circuit breaker 30 is guaranteed to be tripped in time, so that the photovoltaic inverter is protected; the closing electromagnet 31 is driven by the self-connected dc power source Vdc to close, so that the tripped frame circuit breaker 30 is reset.
It should be noted that, in the embodiment of the present invention, the selected frame circuit breaker 30 may preferably adopt a circuit breaker meeting the following conditions:
(1) the frame breaker with mechanical life of 15000-.
According to the requirement of the service life of the inverter 21 in the inverter unit 20 and the requirement of protecting the inverter unit 20 by opening the frame circuit breaker 30, the closing and opening times of the frame circuit breaker 30 are far longer than the mechanical service life of the frame circuit breaker in the conventional inverter.
(2) A frame breaker is selected that does not contain a switch that requires manual closing.
This function is different from the frame circuit breaker among the conventional inverter, and the main objective is in order to prevent that personnel that do not pass through professional training or other irrelevant personnel maloperation, and manual closed does not need closed switch, leads to the electric wire netting to irritate the direct current side backward, damages power devices such as IGBT, arouses bigger trouble.
(3) A frame circuit breaker is selected that contains an undervoltage trip and should not have an off-time greater than 60 ms.
The undervoltage release and the shunt release are powered by different power supplies, so that the undervoltage release can protect an inversion unit when a system power supply fails and the inversion unit needs to be protected but a frame circuit breaker is not released in time; when the inverter unit needs protection, the off time of the frame circuit breaker should not be too long, and if the off time is too long, the grid is caused to reversely flow into the direct current side, power devices such as Insulated Gate Bipolar Transistor (IGBT) and the like are damaged, and a larger fault is caused, so that the frame circuit breaker with the off time not greater than 60ms needs to be selected.
(4) A frame circuit breaker with a suitable ac breaking capacity is selected.
The breaking capacity of the selected frame circuit breaker is required to be larger than the short-circuit current of the line; if the short-circuit current of the line is larger than the breaking capacity of the frame breaker, the frame breaker cannot be normally broken, so that the reverse-flow direct-current side of a power grid is caused, power devices such as Insulated Gate Bipolar Transistor (IGBT) and the like are damaged, and more serious faults are caused; specifically, this breaking capacity is determined by the capacity size of the inverter 21 in the inverter unit 20.
(6) The insulation voltage and the electrical gap of the frame circuit breaker need to satisfy certain conditions.
The embodiment of the utility model provides an in, because there is not the contactor among the photovoltaic inverter, the inverter 21 breaks down and needs to exchange frame circuit breaker and divide by oneself when breaking off the alternating current net side to be connected between disconnection and the electric wire netting, in order to satisfy the ann rule of mechanical life and frame circuit breaker inside, when switch contact is in the open mode, sound contact needs to satisfy 1500vdc insulating voltage and the electric clearance more than 8 mm.
Fig. 3 is a structural diagram of a frame circuit breaker according to an embodiment of the present invention.
In order to effectively trip the frame circuit breaker 30, a background system is required to monitor a corresponding relationship between a grid voltage and an inverter voltage, and issue a tripping command in case of a fault, and a specific implementation manner is shown in fig. 3 in order to ensure reliable tripping of the frame circuit breaker.
Alternatively, as shown in fig. 3, the shunt release 32 includes a shunt release drive K1 and a shunt coil F1; the first end of the shunt tripping drive K1 is connected with the positive electrode Vdc + of the self-connected direct-current power supply Vdc, the second end of the shunt tripping drive K1 is connected with the first end of the shunt coil F1, and the second end of the shunt coil F1 is connected with the negative electrode Vdc-of the self-connected direct-current power supply Vdc. Typically, the value of the self-connected dc power source Vdc is 220V.
The undervoltage release 33 comprises an undervoltage release drive K2, an undervoltage coil Q2 and a first normally open contact K5; the first end of the undervoltage tripping drive K2 is connected with a phase line Vac-L of the self-connected alternating current power supply Vac, the second end of the undervoltage tripping drive K2 is connected with the first end of an undervoltage coil Q2, and the second end of the undervoltage coil Q2 is connected with a neutral line Vac-N of the self-connected alternating current power supply Vac through a first normally open contact K5. Generally, the value of the ac power Vac may be 220V.
Optionally, as shown in fig. 3, the frame circuit breaker further includes a first power supply switch K3, a second power supply switch K4, and a remote control button SW 1; the first power supply switch K3 is linked with the second power supply switch K4; the first power supply switch K3 is disposed between the first normally open contact K5 and the neutral line Vac-N of the self-connected ac power source Vac; the first end of the second power supply switch K4 is connected to the phase line Vac-L of the self-connected ac power source Vac, the second end of the second power supply switch K4 is connected to the first end of the remote control button SW1, and the second end of the remote control button SW1 is connected to the first end of the undervoltage coil Q2.
Specifically, the frame circuit breaker 30 can be implemented as follows:
(1) tripping of the frame circuit breaker 30 is achieved solely by shunt tripping.
When the system judges that a fault occurs and the photovoltaic inverter needs to be off-grid, a shunt tripping command is sent to the shunt tripping device 32, after the shunt tripping command is received, the shunt tripping device in the shunt tripping device 32 drives the K1 to be closed, and at the moment, the frame circuit breaker 30 can realize normal tripping without sending an undervoltage tripping command to the undervoltage tripping device 33 additionally by the system.
(2) Tripping of the frame circuit breaker 30 is accomplished by remote tripping.
(3) Tripping of the frame circuit breaker 30 is achieved by an undervoltage trip.
When the frame circuit breaker 30 is closed, the first normally open contact K5 is in a closed state, when the system judges that a fault occurs and the photovoltaic inverter needs to be disconnected from the grid, an under-voltage tripping command is sent to the under-voltage tripper 33, after the command is received, the under-voltage tripper in the under-voltage tripper 33 drives the K2 to be disconnected, and at the moment, the frame circuit breaker 30 can realize normal tripping without the need of the system additionally sending a shunt tripping command to the shunt tripper 32.
(4) Tripping of the frame circuit breaker 30 is achieved simultaneously by shunt tripping and undervoltage tripping.
When the system judges that a fault occurs and the photovoltaic inverter needs to be off-grid, a shunt tripping command is sent to the shunt tripping device 32, after the shunt tripping command is received, the shunt tripping in the shunt tripping device 32 drives K1 to be closed, and at the moment, the frame circuit breaker 30 can realize normal tripping; if this moment when leading to frame circuit breaker 30 unable normal tripping because of the fault of self-tapping DC power supply Vdc, frame circuit breaker 30's first normally open contact K5 is in the closure state, and the system can detect first normally open contact K5 unusual to send the under-voltage tripping command, because under-voltage release 33 is through the power supply of self-tapping AC power supply Vac, consequently the fault of self-tapping DC power supply Vdc does not influence the work through under-voltage release 33, thereby make frame circuit breaker 30 can carry out the under-voltage tripping smoothly.
(5) Tripping of the frame circuit breaker 30 is achieved simultaneously with remote tripping via shunt tripping.
When the system judges that a fault occurs and the photovoltaic inverter needs to be off-grid, a shunt tripping command is sent to the shunt tripping device 32, after the shunt tripping command is received, the shunt tripping in the shunt tripping device 32 drives K1 to be closed, and at the moment, the frame circuit breaker 30 can realize normal tripping; if normal tripping is not performed due to the self-connected direct current power supply Vdc, the first normally open contact K5 of the frame circuit breaker 30 is in a closed state, and if abnormal warning is found by a power station manager, the remote control button SW1 can be controlled to disconnect the remote control button SW 1.
(6) Tripping of the frame circuit breaker 30 is achieved simultaneously through shunt tripping, undervoltage tripping and remote tripping.
When the system judges that a fault occurs and the photovoltaic inverter needs to be off-grid, a shunt tripping command is sent to the shunt tripping device 32, after the shunt tripping command is received, the shunt tripping in the shunt tripping device 32 drives K1 to be closed, and at the moment, the frame circuit breaker 30 can realize normal tripping; if the frame circuit breaker 30 cannot be normally tripped due to the self-connected direct-current power supply Vdc, the first normally open contact K5 of the frame circuit breaker is in a closed state, the system detects that the first normally open contact K5 is abnormal, so that an under-voltage tripping command is sent, and the frame circuit breaker 30 executes under-voltage tripping; if at this moment, the frame circuit breaker 30 cannot be normally tripped due to shunt tripping and undervoltage tripping, the first normally open contact K5 of the frame circuit breaker 30 is in a closed state, and if a power station manager finds abnormal alarm, the power station manager can control the remote control button SW1 to disconnect the remote control button SW1, and because the power used for remote tripping is the self-connected alternating-current power supply Vac, the self-connected direct-current power supply Vdc fails without affecting the execution of remote tripping, so that the frame circuit breaker 30 can smoothly execute remote tripping, and great loss is avoided.
By using the method, the photovoltaic inverter can realize grid connection and grid disconnection of the photovoltaic inverter by controlling the actuation and the disconnection of the frame circuit breaker according to the relation between real-time inversion voltage and power grid voltage without depending on a contactor; the damage of the inverter caused by the misoperation of the traditional circuit breaker is avoided, the manufacturing cost of the photovoltaic inverter is reduced, the size of the high-power photovoltaic inverter is reduced, the power density of the photovoltaic inverter is improved, and the stable operation of the photovoltaic inverter is ensured.
Fig. 4 is a structural diagram of another photovoltaic inverter according to an embodiment of the present invention.
Optionally, as shown in fig. 4, a direct current Bus DC-Bus, a plurality of normally closed switches QF and a plurality of photovoltaic panels PV are connected in sequence at the direct current input side; the photovoltaic panel PV is used to capture solar energy and concentrate the captured solar energy onto a DC Bus DC-Bus.
Specifically, the photovoltaic panel PV converges the acquired solar energy on the DC-Bus through the normally closed switch QF, and converts the electric energy on the DC-Bus into three-phase alternating current through a plurality of inverter devices, and then connects the three-phase alternating current to the grid through the frame breaker 30; the normally closed switch QF is used for disconnecting the photovoltaic panel PV from the direct current Bus DC-Bus when the equipment is overhauled.
Optionally, as shown in fig. 4, a plurality of first HALL sensors HALL1-N and a plurality of fuses Fu are further disposed between the DC-Bus and the normally closed switch QF, where N ═ 1, 2, 3 … …, and N denotes a number of the first HALL sensor; each fuse Fu is connected between the positive electrode PV + of one photovoltaic panel and the normally-closed switch QF; each first HALL sensor HALL1-N is connected between the negative pole PV-of one photovoltaic panel and the normally closed switch QF.
Specifically, a fuse is also arranged between the positive electrode PV + of the photovoltaic panel and the normally closed switch QF and is used for protecting a circuit; and a first Hall sensor HALL1-N is also arranged between the negative electrode PV-of the photovoltaic panel and the normally closed switch QF and is used for collecting voltage signals on a line in real time and transmitting the collected voltage signals to a power grid monitoring end so as to monitor the state of the line in real time.
Optionally, as shown in fig. 4, a Bus capacitor Cn is further disposed between the direct current input side and the direct current Bus DC-Bus; the positive electrode of the Bus capacitor Cn is respectively connected with the positive electrode DC-Bus of the DC-Bus and the positive electrode of the DC input side; the negative electrode of the Bus capacitor Cn is respectively connected with the negative electrode DC-Bus-of the direct current Bus DC-Bus and the negative electrode of the direct current input side.
Specifically, a Bus capacitor Cn is further disposed between the DC Bus DC-Bus and the DC input side, and is used for providing electric energy for the inverter device in the inverter unit 20 through the energy storage function of the capacitor.
Optionally, as shown in fig. 4, the inverter unit 20 includes a plurality of inverter devices and a plurality of second HALL sensors HALL2-M, where M is 1, 2, 3 … …, and M denotes the number of the first HALL sensor; a second HALL sensor HALL2-M is arranged between a phase output of an inverter output side and the frame breaker 30.
Specifically, the inverter unit 20 and each phase output line on the output side are respectively provided with a second HALL sensor HALL2-M, see fig. 3, that is, the second HALL sensor HALL2-1, the second HALL sensor HALL2-2, the second HALL sensor HALL2-6, and the like, for acquiring voltage signals on each output line on the output side of the inverter device in real time, and transmitting the acquired voltage signals to the power grid monitoring terminal to monitor whether the line is overcurrent or not and is in a safety zone in real time.
Optionally, as shown in fig. 4, the inverter unit 20 further includes a plurality of inductors L and a plurality of capacitors C; an inductance L is arranged between a second HALL sensor HALL2-M and the frame breaker 30; the capacitor C is disposed between the inductor and the frame breaker 30, and the capacitor C is connected in parallel between the two output lines at the output side of the inverter.
Specifically, a plurality of inductors L and a plurality of capacitors C are further disposed between the inverter device and the frame circuit breaker 30, see fig. 4, i.e., L1, L2, … … L6, C1, C2, … … C18, etc., and for example, only a part of the capacitors are drawn in fig. 4. The inverter 21 is converted into standard three-phase alternating current of 50Hz or 60Hz by setting an inductor and a capacitor for filtering.
Optionally, as shown in fig. 4, the inverting unit 21 further includes a plurality of transformers CF; the same phase output of the output sides of the plurality of inverter devices is connected with a primary side loop of the same transformer CF; the secondary side circuit of the transformer CF is connected to the frame breaker 30.
In particular, the plurality of transformers CF are usually current transformers for measuring the current value in the line in real time to ensure that the line operates normally.
Optionally, as shown in fig. 4, the DC-Bus is further connected to a first surge protector SPD1, and the ac output side is further connected to a second surge protector SPD 2; the first surge protector SPD1 is respectively connected with the positive pole DC-Bus + and the negative pole DC-Bus-of the DC-Bus; the second surge protectors SPD2 are connected to the three-phase output lines on the ac output side, respectively.
Specifically, surge protectors are connected to the DC-Bus and the three-phase output line on the ac output side, and are used to conduct and shunt current in a very short time when a peak current or voltage is suddenly generated in the line due to external interference, thereby preventing damage of the surge to other devices on the line.
The utility model discloses a photovoltaic inverter, which comprises an inverter unit and a frame breaker which are sequentially connected between a direct current input side and an alternating current output side; the inverter unit is electrically connected with the direct current input side, and the frame circuit breaker is electrically connected with the alternating current output side; the frame circuit breaker is externally connected with a circuit breaker self-connection power supply, and the circuit breaker self-connection power supply supplies power to the frame circuit breaker, wherein the circuit breaker self-connection power supply comprises a self-connection direct current power supply and a self-connection alternating current power supply; the frame circuit breaker comprises a closing electromagnet, a shunt release and an undervoltage release; the self-connecting direct current power supply is respectively connected with the closing electromagnet and the shunt release, and the self-connecting alternating current power supply is connected with the undervoltage release. The photovoltaic inverter grid-connected operation can be realized without a contactor or through a frame breaker, the damage of the inverter caused by the misoperation of the traditional breaker is avoided, the manufacturing cost of the photovoltaic inverter is reduced, the size of the high-power photovoltaic inverter is reduced, the power density of the photovoltaic inverter is improved, and the stable operation of the photovoltaic inverter is ensured.
In the description of the embodiments of the present invention, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Finally, it should be noted that the above description is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.
Claims (10)
1. A photovoltaic inverter is characterized by comprising an inverter unit and a frame breaker which are sequentially connected between a direct current input side and an alternating current output side; the inverter unit is electrically connected with the direct current input side, and the frame circuit breaker is electrically connected with the alternating current output side;
the frame circuit breaker is externally connected with a circuit breaker self-connection power supply, the circuit breaker self-connection power supply supplies power to the frame circuit breaker, and the circuit breaker self-connection power supply comprises a self-connection direct current power supply and a self-connection alternating current power supply;
the frame circuit breaker comprises a closing electromagnet, a shunt release and an undervoltage release; the self-connecting direct-current power supply is respectively connected with the closing electromagnet and the shunt release, and the self-connecting alternating-current power supply is connected with the undervoltage release.
2. The photovoltaic inverter of claim 1, wherein the shunt release comprises a shunt release drive and a shunt coil;
the first end of the shunt tripping drive is connected with the anode of the self-connected direct-current power supply, the second end of the shunt tripping drive is connected with the first end of the shunt coil, and the second end of the shunt coil is connected with the cathode of the self-connected direct-current power supply;
the undervoltage release comprises an undervoltage release drive, an undervoltage coil and a first normally open contact;
the first end of the undervoltage tripping drive is connected with the phase line of the self-connected alternating current power supply, the second end of the undervoltage tripping drive is connected with the first end of the undervoltage coil, and the second end of the undervoltage coil is connected with the neutral line of the self-connected alternating current power supply through a first normally open contact.
3. The photovoltaic inverter of claim 2, wherein the frame circuit breaker further comprises a first power switch, a second power switch, and a remote control button; the first power supply switch is linked with the second power supply switch;
the first power supply switch is arranged between the first normally open contact and a neutral line of the self-connected alternating current power supply;
the first end of the second power supply switch is connected with the phase line which is connected with the alternating current power supply, the second end of the second power supply switch is connected with the first end of the remote control button, and the second end of the remote control button is connected with the first end of the undervoltage coil.
4. The photovoltaic inverter of claim 1, wherein the dc input side is connected in sequence with a dc bus, a plurality of normally closed switches, and a plurality of photovoltaic panels;
the photovoltaic panel is used for acquiring solar energy and converging the acquired solar energy onto the direct current bus.
5. The photovoltaic inverter of claim 4, wherein a plurality of first Hall sensors and a plurality of fuses are further disposed between the DC bus and the normally closed switch;
each fuse is connected between the positive electrode of one photovoltaic panel and the normally-closed switch; each first Hall sensor is connected between the negative electrode of one photovoltaic panel and the normally closed switch.
6. The photovoltaic inverter of claim 4, wherein a bus capacitor is further disposed between the DC input side and the DC bus; the positive electrode of the bus capacitor is respectively connected with the positive electrode of the direct current bus and the positive electrode of the direct current input side;
and the cathode of the bus capacitor is respectively connected with the cathode of the direct current bus and the cathode of the direct current input side.
7. The photovoltaic inverter according to claim 4, wherein the inverter unit includes a plurality of inverter devices and a plurality of second Hall sensors; one of the second hall sensors is disposed between one phase output of the output side of one of the inverter devices and the frame circuit breaker.
8. The photovoltaic inverter of claim 7, wherein the inverter unit further comprises a plurality of inductors and a plurality of capacitors;
one said inductor is disposed between one said second hall sensor and said frame circuit breaker;
the capacitor is arranged between the inductor and the frame circuit breaker and is connected between two output lines of the output side of the inverter in parallel.
9. The photovoltaic inverter of claim 7, wherein the inverter unit further comprises a plurality of transformers; the same phase output of the output sides of the plurality of inverter devices is connected with a primary side loop of the same transformer; and a secondary side loop of the mutual inductor is connected with the frame breaker.
10. The photovoltaic inverter according to claim 4, wherein a first surge protector is further connected to the DC bus, and a second surge protector is further connected to the AC output side;
the first surge protector is respectively connected with the anode and the cathode of the direct current bus;
the second surge protectors are connected to the three-phase output lines on the ac output side, respectively.
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