CN114498746A - Inverter circuit, inverter control method and photovoltaic system - Google Patents
Inverter circuit, inverter control method and photovoltaic system Download PDFInfo
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- CN114498746A CN114498746A CN202210107424.2A CN202210107424A CN114498746A CN 114498746 A CN114498746 A CN 114498746A CN 202210107424 A CN202210107424 A CN 202210107424A CN 114498746 A CN114498746 A CN 114498746A
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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
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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
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
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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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
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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
- 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
- H02M7/53871—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 with automatic control of output voltage or current
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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
- 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
Abstract
The invention provides an inverter circuit, an inverter control method and a photovoltaic system, wherein the inverter circuit comprises a power circuit and a signal circuit; the power circuit provides a sampling signal for the signal circuit; the signal circuit outputs a switching tube driving signal to drive a switching tube in the power circuit according to the sampling signal; the power circuit can control the connection and disconnection of the photovoltaic module to be connected according to the driven switching tube. The invention realizes the direct access of a single component (or two components connected in series), and each input is connected with a shutdown circuit to realize the safety shutdown and optimization functions.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation, in particular to an inverter circuit, an inverter control method and a photovoltaic system.
Background
With the development of human industry, fossil energy utilization continuously puts various stresses on the environment, the development and utilization of clean new energy are accelerated in all countries in the world, and solar energy is more and more favored by people due to the characteristics of cleanness, harmlessness, wide distribution and the like. Photovoltaic power generation also becomes a hot spot of current distributed new energy power generation. The inverter is a converter which converts direct current electric energy (batteries and storage batteries) into constant-frequency constant-voltage or frequency-modulation voltage-regulation alternating current (generally 220V,50Hz sine wave). It is composed of inverter bridge, control logic and filter circuit.
According to the conventional scheme shown in fig. 1, photovoltaic modules are connected in series and then connected to the input of an inverter, the input is boosted by BOOST to reach the voltage required by a bus, and then the voltage is converted into alternating current by an H-bridge inverter.
Chinese utility model patent document with publication number CN206850682U discloses a photovoltaic inverter circuit, including: the photovoltaic module comprises a first photovoltaic module PV1, a second photovoltaic module PV2, a first Buck circuit, a second Buck circuit, a first flyback circuit, a second flyback circuit, a third Buck circuit and an inverter circuit; the input of the first Buck circuit is connected with the first photovoltaic module PV1, the input of the second Buck circuit is connected with the second photovoltaic module PV2, and the outputs of the two Buck circuits are connected with the inputs of the first flyback circuit and the second flyback circuit; the outputs of the first flyback circuit and the second flyback circuit are connected with the inverter circuit; the input of the third Buck circuit is connected with leakage inductance absorption capacitors C1 and C2 of a flyback transformer, and the output of the third Buck circuit is connected with the input Vin + of the first flyback circuit and the second flyback circuit.
For the prior art, the inventor thinks that after the power grid is disconnected in the traditional scheme, the system still has high voltage, and personal safety cannot be guaranteed.
Disclosure of Invention
In view of the defects in the prior art, the present invention provides an inverter circuit, an inverter control method and a photovoltaic system.
The invention provides an inverter circuit, which comprises a power circuit and a signal circuit;
the power circuit provides a sampling signal for the signal circuit;
the signal circuit outputs a switching tube driving signal to drive a switching tube in the power circuit according to the sampling signal;
the power circuit can control the connection and disconnection of the photovoltaic module to be connected according to the driven switching tube.
Preferably, the signal circuit includes an auxiliary power supply unit and a control unit;
the auxiliary power supply unit is connected with a to-be-connected power grid and provides power for the control unit;
the control unit processes the sampling signal and outputs a switching tube driving signal to control the switching tube.
Preferably, the power circuit comprises a switching circuit and an inverter circuit;
the first input end of the switch circuit can be connected with the first output end of the photovoltaic module to be connected;
the second input end of the switch circuit can be connected with the second output end of the photovoltaic module to be connected;
the first output end of the first switch circuit is connected with the first input end of the inverter circuit;
the first output end and the second output end of the adjacent switch circuit are connected with each other;
a second output end of the tail switch circuit is connected with a second input end of the inverter circuit;
and the first output end and the second output end of the inverter circuit can be connected with a to-be-connected power grid.
Preferably, the switching circuit comprises a Buck circuit;
the first input end of the Buck circuit is the second input end of the switch circuit;
the second input end of the Buck circuit is the first input end of the switch circuit;
the first output end of the Buck circuit is the second output end of the switch circuit;
and the second output end of the Buck circuit is the first output end of the switch circuit.
Preferably, the Buck circuit comprises a fourth capacitor C4, a fifth capacitor C5, a seventh switch Q7, an eighth switch Q8 and a third inductor L3;
one end of the fourth capacitor C4 is a first input end of the Buck circuit, and one end of the fourth capacitor C4 is connected to one end of the eighth switch Q8;
the other end of the eighth switch Q8 is respectively connected with one end of the seventh switch Q7 and one end of the third inductor L3;
the other end of the third inductor L3 is connected with one end of the fifth capacitor C5;
one end of the fifth capacitor C5 is a first output end of the Buck circuit;
the other end of the fourth capacitor C4 is a second input end of the Buck circuit, and the other end of the fourth capacitor C4 is connected to the other end of the seventh switch Q7 and the other end of the fifth capacitor C5;
the other end of the fifth capacitor C5 is a second output end of the Buck circuit.
Preferably, the inverter circuit includes an H-bridge circuit;
the first input end of the H-bridge circuit is the first input end of the inverter circuit;
the second input end of the H-bridge circuit is the second input end of the inverter circuit;
the first output end of the H-bridge circuit is the first output end of the inverter circuit;
the first output end of the H-bridge circuit is the second output end of the inverter circuit.
According to the present invention, there is provided an inverter including a case and an inverter circuit provided in the case.
The invention provides an inverter control method, which comprises the following steps:
a signal providing step: providing a sampling signal;
a driving step: outputting a switching tube driving signal to drive a switching tube according to the sampling signal;
a switch control step: according to the driven switching tube, the switching-off and the communication of the photovoltaic module to be connected can be controlled.
Preferably, the switching tube includes a seventh switch Q7 and an eighth switch Q8.
The photovoltaic system comprises an inverter, a power grid and a photovoltaic assembly;
the photovoltaic modules are connected with inverters;
the inverter is connected with a power grid.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention realizes the direct access of a single photovoltaic module (or two modules connected in series), and each input (photovoltaic module) is connected with a turn-off circuit to realize the safety turn-off and optimization functions;
2. according to the photovoltaic power generation system, a single photovoltaic module is connected into an inverter circuit, then the photovoltaic modules are connected in series through a Buck circuit and then connected into a BOOST circuit, then inversion is carried out through the inverter circuit, after a power grid is disconnected, the fact that each photovoltaic module is disconnected is guaranteed, the system does not have high voltage, the safety of the system is guaranteed, and due to the fact that each photovoltaic module is integrated with one Buck circuit, maximum power tracking can be achieved under the condition that the photovoltaic modules are shielded, and the efficiency of the photovoltaic system is improved;
3. the photovoltaic modules are connected into the inverter circuit, then are connected in series through the Buck circuit and then are inverted through the inverter circuit, after a power grid is disconnected, the disconnection of each photovoltaic module is ensured, the system does not have high voltage, the safety of the system is ensured, and each input unit (photovoltaic module) independently performs maximum power tracking due to the fact that each module integrates the Buck circuit, and the maximum efficiency of the system is achieved;
4. the switching tube is driven by the signal circuit, so that the accuracy and convenience of controlling the photovoltaic module to be connected are improved.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic circuit diagram of a conventional scheme;
FIG. 2 is a circuit diagram according to a first embodiment of the present invention;
fig. 3 is a structural diagram of a photovoltaic system according to a first embodiment of the present invention;
FIG. 4 is a circuit diagram illustrating a second embodiment of the present invention;
FIG. 5 is a circuit diagram illustrating a third embodiment of the present invention;
fig. 6 is a circuit diagram of a fourth embodiment of the invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.
An inverter circuit according to an embodiment of the present invention is disclosed, and as shown in fig. 2, includes a switching circuit(s) and an inverter circuit. The switching circuit and the photovoltaic module to be connected are correspondingly arranged, and a first input end of the switching circuit can be connected with a first output end of the photovoltaic module to be connected; the second input end of the switch circuit can be connected with the second output end of the photovoltaic module to be connected. The first output end of the first switch circuit is connected with the first input end of the inverter circuit; the first output end and the second output end of the adjacent switch circuit are connected with each other; the second output end of the tail switch circuit is connected with the second input end of the inverter circuit; the first output end and the second output end of the inverter circuit can be connected with a to-be-connected power grid. And the first output end of the photovoltaic module to be connected is output positive, and the second output end of the photovoltaic module to be connected is output negative.
The inverter circuit comprises a third capacitor C3, an inverter unit and a booster circuit; one end of the third capacitor C3 is a first input end of the inverter circuit, and one end of the third capacitor C3 is connected to the first input end of the boost circuit; the other end of the third capacitor C3 is a second input end of the inverter circuit, and the other end of the third capacitor C3 is connected to a second input end of the boost circuit; the first output end of the booster circuit is connected with the first input end of the inversion unit; the second output end of the booster circuit is connected with the second input end of the inversion unit; the first output end of the inversion unit is the first output end of the inversion circuit; and the second output end of the inversion unit is the second output end of the inversion circuit.
The inverter unit includes an H-bridge circuit. The H-bridge circuit includes a bus capacitor CBUS, a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, and a first inductor L1. One end of the bus capacitor CBUS is a first input end of the inverter unit, and one end of the bus capacitor CBUS is connected to one end of the first switch Q1 and one end of the second switch Q2 respectively. One end of the first switch Q1 is connected to one end of the first inductor L1 and one end of the third switch Q3, respectively; the other end of the first inductor L1 is a first output end of the inverting unit. The other end of the second switch Q2 is a second output end of the inverting unit, and the other end of the second switch Q2 is connected to one end of the fourth switch Q4. The other end of the bus capacitor CBUS is a second input end of the inverter unit, and the other end of the bus capacitor CBUS is connected to the other end of the third switch Q3 and the other end of the fourth switch Q4, respectively.
The switching circuit includes a turn-off circuit. The turn-off circuit includes a first capacitor C1, a second capacitor C2, a first diode D1, and a fifth switch Q5. One end of the first capacitor C1 is a first input end of the switch circuit, and one end of the first capacitor C1 is connected to the cathode of the first diode D1 and one end of the second capacitor C2 respectively; one end of the second capacitor C2 is a first output end of the switch circuit; the other end of the first capacitor C1 is a second input end of the switch circuit, and the other end of the first capacitor C1 is connected to one end of a fifth switch Q5; the other end of the fifth switch Q5 is connected to the anode of the first diode D1 and the other end of the second capacitor C2 respectively; the other end of the second capacitor C2 is a second output terminal of the switch circuit.
The Boost circuit includes a Boost circuit. The name of the Boost circuit is a Boost Chopper circuit, and the name of the Boost circuit is Boost Chopper. The Boost circuit includes a second inductor L2, a second diode D2, and a sixth switch Q6. One end of the second inductor L2 is a first input end of the voltage boost circuit, the other end of the second inductor L2 is connected to one end of the sixth switch Q6 and the anode of the second diode D2, respectively, and the cathode of the second diode D2 is a first output end of the voltage boost circuit. The other end of the sixth switch Q6 is a second input end of the voltage boost circuit and a second output end of the voltage boost circuit.
As shown in fig. 2, a single photovoltaic module PV is connected to the above scheme, and then is connected in series through a shutdown circuit to be connected to a Boost circuit, and then is connected to an H-bridge inverter. When the power grid is disconnected, safe disconnection can be realized, and the system is ensured not to have high-voltage risk.
The position of the fifth switch Q5 is not limited to be placed at the low end, but may be placed between one end of the first capacitor C1 and the cathode of the first diode D1, and the second diode D2 may also be a switch tube. The inverter unit at the later stage is not limited to the H-bridge, and may be in H6 topology, Heric topology or three-phase topology. Heric is known as the high Efficient Reliable Inverter Concept, and Chinese translation is a non-isolated photovoltaic Inverter.
The first embodiment of the invention also discloses an inverter, which comprises a shell and an inverter circuit, wherein the inverter circuit is arranged in the shell, as shown in fig. 3. The housing comprises an aluminum shell.
As shown in fig. 3, each photovoltaic module is individually connected to an input side of the micro inverter, and the photovoltaic module is internally boosted to a voltage required by the inverter unit through a DC-DC circuit (Boost circuit), and then transmits power to the grid through the H-bridge. The DC-DC Chinese translation is a DC-DC converter. DC is called Direct Current in English, and Chinese translation is Direct Current. AC is called Alternating Current in English, and Chinese translation is AC.
The first embodiment of the invention also discloses a photovoltaic system, which comprises an inverter, a power grid and photovoltaic module(s), as shown in fig. 3. The photovoltaic modules are connected with the inverter; the inverter is connected with a power grid.
The second embodiment of the invention also discloses an inverter circuit, and as shown in fig. 4, the difference from the first embodiment is that the switching circuit comprises a Buck circuit. The first input end of the Buck circuit is the first input end of the switch circuit. The second input end of the Buck circuit is the second input end of the switch circuit. The first output end of the Buck circuit is the first output end of the switch circuit. And the second output end of the Buck circuit is the second output end of the switch circuit.
The Buck circuit comprises a fourth capacitor C4, a fifth capacitor C5, a seventh switch Q7, an eighth switch Q8 and a third inductor L3. One end of the fourth capacitor C4 is a first input end of the Buck circuit, one end of the fourth capacitor C4 is connected with one end of the eighth switch Q8, the other end of the eighth switch Q8 is connected with one end of the seventh switch Q7 and one end of the third inductor L3 respectively, the other end of the third inductor L3 is connected with one end of the fifth capacitor C5, and one end of the fifth capacitor C5 is a first output end of the Buck circuit. The other end of the fourth capacitor C4 is a second input end of the Buck circuit, and the other end of the fourth capacitor C4 is connected to the other end of the seventh switch and the other end of the fifth capacitor C5. The other end of the fifth capacitor C5 is a second output end of the Buck circuit.
Because MPPT of a group cluster of traditional dc-to-ac converter can't solve and shelter from the problem that causes system inefficiency. As shown in fig. 4, a single photovoltaic module is connected to the above scheme, and then is connected in series to the Boost circuit after passing through a Buck circuit, and then is inverted through an H-bridge, which has the advantages that: 1. after the power grid is disconnected, each photovoltaic module is ensured to be disconnected, and the system does not have high voltage, so that the safety of the system is ensured; that is, after the power grid is disconnected, the driving power supply of the fifth switching tube Q5 and the power supply of the CPU are disconnected, so that the fifth switching tube Q5 has no driving voltage, the input and the output are disconnected, and the inputs are disconnected. 2. Because each photovoltaic module is integrated with a Buck circuit, the maximum power tracking can be realized under the condition that the module is shielded, and the efficiency of a photovoltaic system is improved. MPPT is called Maximum Power Point Tracking in English, and Chinese translation is Maximum Power Point Tracking.
The positions of the seventh switch Q7 and the eighth switch Q8 are not limited to being placed at the low end. When the power grid is disconnected, safe disconnection can be realized, and the system is ensured not to have high-voltage risk; and the shielding component or the component with low power is independently used for MPPT, so that the power generation capacity of the system is improved.
The third embodiment of the invention also discloses an inverter circuit, as shown in fig. 5, which is different from the second embodiment in that a second input end of the Buck circuit is a first input end of the switch circuit; the first input end of the Buck circuit is the second input end of the switch circuit; the second output end of the Buck circuit is the first output end of the switch circuit; the first output end of the Buck circuit is the second output end of the switch circuit. The inverter circuit comprises a third capacitor C3 and an inverter unit; one end of the third capacitor C3 is a first input end of the inverter circuit, and one end of the third capacitor C3 is connected to the first input end of the inverter unit; the other end of the third capacitor C3 is a second input end of the inverter circuit, and the other end of the third capacitor C3 is connected to a second input end of the inverter unit; the first output end of the inversion unit is the first output end of the inversion circuit; the first output end of the inversion unit is the second output end of the inversion circuit. The inverter unit includes an H-bridge circuit.
As shown in fig. 5, one or more photovoltaic modules are connected in series and then connected into the above scheme, and then are connected in series through a Buck circuit and then are inverted through an H-bridge, which has the advantages that: 1. after the power grid is disconnected, each photovoltaic module (input) is disconnected, the system does not have high voltage, and the safety of the system is guaranteed. After the power grid is disconnected, the driving power supply of the seventh switching tube Q7 and the eighth switching tube Q8 and the power supply of the CPU are disconnected, so that the switching tube Q5 has no driving voltage, the input and the output are disconnected, and the input is disconnected. 2. Because each component integrates a Buck circuit (Buck circuit is reversely arranged), each input unit independently performs maximum power tracking, and the maximum efficiency of the system is realized. When the power grid is disconnected, safe disconnection can be realized, and the system is ensured not to have high-voltage risk; each input is independently used as MPPT, and the system efficiency is high. The invention realizes the direct access of a single component (or two components connected in series), and each input is connected with a turn-off circuit or a Buck circuit to realize the safety turn-off and optimization functions.
The fourth embodiment of the invention also discloses a novel micro inverter circuit and a control method thereof, and as shown in fig. 6, the difference from the third embodiment is that the inverter circuit comprises an H-bridge circuit; the first input end of the H-bridge circuit is the first input end of the inverter circuit; the second input end of the H-bridge circuit is the second input end of the inverter circuit; the first output end of the H-bridge circuit is the first output end of the inverter circuit; the first output end of the H-bridge circuit is the second output end of the inverter circuit.
The novel micro inverter circuit further comprises a power circuit (a switch circuit and an inverter circuit) and a signal circuit, wherein the input of the power circuit is a photovoltaic module, and the output of the power circuit is a power grid. The power circuit provides a sampling signal for the signal circuit; the control unit of the signal circuit outputs switching tube driving signals through signal analysis and operation to drive the switching tubes (a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a seventh switch Q7 and an eighth switch Q8) of the power circuit.
The inverter circuit includes a power circuit and a signal circuit. The power circuit includes 1 or more switching circuits and inverter circuits. The power circuit provides a sampling signal for the signal circuit; the signal circuit outputs a switching tube driving signal to drive a switching tube in the power circuit according to the sampling signal. The power circuit can control the connection and disconnection of the photovoltaic module to be connected according to the driven switching tube.
The signal circuit comprises an auxiliary power supply unit and a control unit; the auxiliary power supply unit is connected with a to-be-connected power grid and provides power for the control unit; the control unit processes the sampling signal and outputs a switching tube driving signal to control the switching tube.
The power circuit includes: fourth electric capacity C4 (input capacitance), eighth switch Q8(Buck switch tube), seventh switch Q7(Buck switch tube), third inductance L3 (filter inductance), fifth electric capacity C5 (output capacitance), BUS capacitance CBUS (BUS electric capacity), first switch tube Q1(H bridge switch tube), second switch tube Q2(H bridge switch tube), third switch tube Q3(H bridge switch tube), fourth switch tube Q4(H bridge switch tube) and first inductance L1 (electric wire netting filter inductance), wherein: the fourth capacitor C4 is connected with the photovoltaic module input in parallel; one end of an eighth switch Q8 is connected with the cathode of the fourth capacitor C4, the other end of the eighth switch Q8 is connected with one end of a third inductor L3, the other end of the third inductor L3 is connected with the cathode of a fifth capacitor C5, and the other end of the fifth capacitor C5 is connected with the anode of the fourth capacitor C4; the fifth capacitors C5 of all Buck circuits are connected in series and then connected with two ends of a bus capacitor CBUS, one end of a first switching tube Q1 is connected with the positive electrode of the bus capacitor CBUS, the other end of the first switching tube Q1 is connected with one end of a third switching tube Q3, the other end of the third switching tube Q3 is connected with the negative electrode of the bus capacitor CBUS, one end of a second switching tube Q2 is connected with the positive electrode of the bus capacitor CBUS, the other end of the second switching tube Q2 is connected with one end of a fourth switching tube Q4, the other end of the fourth switching tube Q4 is connected with the negative electrode of the bus capacitor CBUS, one end of a first inductor L1 is connected with the intersection of the first switching tube Q1 and the third switching tube Q3, the other end of the first inductor L1 is connected with a power grid AC _ L, and the power grid AC _ N is connected with the intersection of the second switching tube Q2 and the fourth switching tube Q4.
The signal circuit includes: the auxiliary power supply unit inputs power grid AC _ L and power grid AC _ N; the output provides power for the control unit; the input of the control unit is an AD sampling signal, and the output of the control unit is a power circuit switching tube driving signal. The auxiliary power supply is obtained by adopting a flyback isolation circuit; the control unit uses the TI DSP 28 series.
Each input (photovoltaic component) in the power circuit is provided with a Buck circuit, and the Buck circuit controls the output voltage of the Buck circuit, so that the voltage after the Buck circuit is connected in series is higher than the starting voltage of an H bridge and is lower than the withstand voltage of a bus capacitor CBUS; after detecting that the voltage of the bus capacitor CBUS is higher than the starting voltage for a certain time, the control unit starts an H-bridge inverter bridge to work, controls the voltage of the bus capacitor CBUS to be at a certain value, and carries out maximum power tracking by collecting the voltage and current of a Buck circuit so as to ensure that the maximum power is output to the bus capacitor CBUS and is output to a power grid through the H-bridge; when the power grid is disconnected, the driving voltage and the driving voltage of the Buck circuit are not available, the eighth switch Q8 and the seventh switch Q7 of the Buck circuit do not work, all the inputs are disconnected, and the safety of the system is guaranteed.
An inverter control method comprising the steps of: a signal providing step: providing a sampling signal; a driving step: outputting a switching tube driving signal to drive a switching tube according to the sampling signal; a switch control step: according to the driven switching tube, the switching-off and the communication of the photovoltaic module to be connected can be controlled. The switching tube includes a seventh switch Q7 and an eighth switch Q8.
Through adopting the structure that 1 or a plurality of Buck are established ties and are added the H bridge, solved the system high pressure problem after the electric wire netting disconnection, reached the effect of protection personal safety, every input all adopts the Buck structure simultaneously, and maximum power tracking can both be done alone to every input, has solved photovoltaic module shadow and has sheltered from and the generated energy reduction problem that power adaptation brought.
In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.
Claims (10)
1. An inverter circuit, comprising a power circuit and a signal circuit;
the power circuit provides a sampling signal for the signal circuit;
the signal circuit outputs a switching tube driving signal to drive a switching tube in the power circuit according to the sampling signal;
the power circuit can control the connection and disconnection of the photovoltaic module to be connected according to the driven switching tube.
2. The inverter circuit according to claim 1, wherein the signal circuit includes an auxiliary power supply unit and a control unit;
the auxiliary power supply unit is connected with a to-be-connected power grid and provides power for the control unit;
the control unit processes the sampling signal and outputs a switching tube driving signal to control the switching tube.
3. The inverter circuit according to claim 1, wherein the power circuit includes a switching circuit and an inverter circuit;
the first input end of the switch circuit can be connected with the first output end of the photovoltaic module to be connected;
the second input end of the switch circuit can be connected with the second output end of the photovoltaic module to be connected;
the first output end of the first switch circuit is connected with the first input end of the inverter circuit;
the first output end and the second output end of the adjacent switch circuit are connected with each other;
a second output end of the tail switch circuit is connected with a second input end of the inverter circuit;
and the first output end and the second output end of the inverter circuit can be connected with a to-be-connected power grid.
4. The inverter circuit according to claim 3, wherein the switching circuit comprises a Buck circuit;
the first input end of the Buck circuit is the second input end of the switch circuit;
the second input end of the Buck circuit is the first input end of the switch circuit;
the first output end of the Buck circuit is the second output end of the switching circuit;
and the second output end of the Buck circuit is the first output end of the switch circuit.
5. The inverter circuit according to claim 4, wherein the Buck circuit comprises a fourth capacitor C4, a fifth capacitor C5, a seventh switch Q7, an eighth switch Q8 and a third inductor L3;
one end of the fourth capacitor C4 is a first input end of the Buck circuit, and one end of the fourth capacitor C4 is connected to one end of the eighth switch Q8;
the other end of the eighth switch Q8 is respectively connected with one end of the seventh switch Q7 and one end of the third inductor L3;
the other end of the third inductor L3 is connected with one end of the fifth capacitor C5;
one end of the fifth capacitor C5 is a first output end of the Buck circuit;
the other end of the fourth capacitor C4 is a second input end of the Buck circuit, and the other end of the fourth capacitor C4 is connected to the other end of the seventh switch Q7 and the other end of the fifth capacitor C5;
the other end of the fifth capacitor C5 is a second output end of the Buck circuit.
6. The inverter circuit according to claim 3, wherein the inverter circuit comprises an H-bridge circuit;
the first input end of the H-bridge circuit is the first input end of the inverter circuit;
the second input end of the H-bridge circuit is the second input end of the inverter circuit;
the first output end of the H-bridge circuit is the first output end of the inverter circuit;
the first output end of the H-bridge circuit is the second output end of the inverter circuit.
7. An inverter with an inverter circuit according to any one of claims 1 to 6, comprising a housing and the inverter circuit, the inverter circuit being arranged in the housing.
8. An inverter control method, characterized by applying the inverter of any one of claims 1 to 6, comprising the steps of:
a signal providing step: providing a sampling signal;
a driving step: outputting a switching tube driving signal to drive a switching tube according to the sampling signal;
a switch control step: according to the driven switching tube, the switching-off and the communication of the photovoltaic module to be connected can be controlled.
9. The inverter control method according to claim 8, wherein the switching tubes include a seventh switch Q7 and an eighth switch Q8.
10. A photovoltaic system with the inverter of claim 7, comprising an inverter, a grid, and a photovoltaic module;
the photovoltaic modules are connected with inverters;
the inverter is connected with a power grid.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210107424.2A CN114498746A (en) | 2022-01-28 | 2022-01-28 | Inverter circuit, inverter control method and photovoltaic system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210107424.2A CN114498746A (en) | 2022-01-28 | 2022-01-28 | Inverter circuit, inverter control method and photovoltaic system |
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| CN101615859A (en) * | 2008-06-27 | 2009-12-30 | 通用电气公司 | High-frequency photovoltaic inverter |
| US20120051101A1 (en) * | 2010-08-28 | 2012-03-01 | General Electric Company | Power inverter system and method of starting same at high dc voltage |
| CN102545257A (en) * | 2012-01-12 | 2012-07-04 | 广东中商国通电子有限公司 | Solar photovoltaic generating single-phase grid-connected inverter and control method thereof |
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| CN101615859A (en) * | 2008-06-27 | 2009-12-30 | 通用电气公司 | High-frequency photovoltaic inverter |
| US20120051101A1 (en) * | 2010-08-28 | 2012-03-01 | General Electric Company | Power inverter system and method of starting same at high dc voltage |
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