WO2018095046A1 - 逆变器反孤岛控制*** - Google Patents
逆变器反孤岛控制*** Download PDFInfo
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- WO2018095046A1 WO2018095046A1 PCT/CN2017/092474 CN2017092474W WO2018095046A1 WO 2018095046 A1 WO2018095046 A1 WO 2018095046A1 CN 2017092474 W CN2017092474 W CN 2017092474W WO 2018095046 A1 WO2018095046 A1 WO 2018095046A1
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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
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
-
- 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
-
- 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
- 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
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/50—Controlling the sharing of the out-of-phase component
-
- 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
- H02M1/081—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters wherein the phase of the control voltage is adjustable with reference to the AC source
-
- 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
-
- 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
- H02M7/53873—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 with digital control
-
- 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
- H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
-
- 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
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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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
- 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
Definitions
- the present invention relates to the field of power system automation technologies, and in particular, to an inverter anti-island control system.
- the inverter When new energy is connected to the grid, DC power is generated.
- the inverter needs to convert the DC energy into AC power through the inverter, and then supply power to the main grid and the load.
- the islanding state of the inverter means that when the grid-connected switch trips, the inverter fails to detect the power-off state of the main grid and cuts itself off the grid, but supplies power to the load as an isolated power source.
- the island state has major hidden dangers to the safety of equipment and personnel: when the maintenance personnel stop the power supply of the main power grid and repair the power lines and circuit equipment, if the inverter of the new energy source continues to supply power to the load, it will cause casualties of the maintenance personnel.
- the grid-connected inverter maintains power supply, when the main grid resumes power supply, the grid voltage and the output voltage of the inverter may have large differences in phase, causing a large inrush current and damage. device.
- the above-mentioned islanding detection strategy usually relies on the over/under voltage or over/under frequency protection mechanism.
- the over/under voltage or over/under frequency protection time of the inverter is greater than the island protection time required by the grid connection standard, There is a case where the island detection fails.
- An embodiment of the present invention provides an inverter anti-island control system, which can use a phase shift loop to shift the frequency of the AC terminal voltage of the inverter to a second frequency to cause a trigger frequency when the inverter is in an island state. Protection thus disconnects from the grid, ie out of the island state.
- the embodiment of the invention discloses an inverter anti-island control system, which comprises:
- the phase shifting ring includes a first input end, a second input end, a third input end, a fourth input end, a first output end, and a second output end;
- the driving circuit includes a first input end and a second input end , a third input end and an output end;
- a first output end of the phase shifting ring is connected to a first input end of the driving circuit, and a second output end of the phase shifting ring is connected to a second input end of the driving circuit;
- the phase shifting loop is configured to apply an active voltage command according to the frequency protection information of the inverter AC terminal voltage and the grid connection standard And reactive voltage command Perform phase shift conversion to obtain the active voltage command after phase shifting Reactive voltage command after phase shifting Wherein Said And the frequency protection information in the inverter AC terminal voltage and the grid-connected standard respectively reach the first input end, the second input end, the third input end, and the fourth input end of the phase shifting loop Phase shifting ring; Receiving, via the first output of the phase shifting loop, a first input of the drive circuit, Passing through the second output end of the phase shifting loop to the second input end of the driving circuit;
- the drive circuit is for with Generating a drive signal; the drive signal reaches the inverter via an output of the drive circuit to drive the inverter to output an AC voltage having a second frequency, the second frequency being used to control disconnection or The connection between the inverter and the grid is maintained.
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnect from the grid, that is, get out of the island state.
- the phase shifting ring includes a phase shifting angle generating circuit and a phase shifting matrix circuit, wherein:
- the phase shifting angle generating circuit includes a first input end, a second input end, and an output end; the phase shifting matrix circuit includes a first input end, a second input end, a third input end, a first output end, and a second Output
- An output end of the phase shift angle generating circuit is connected to a third input end of the phase shifting matrix circuit
- the phase shift angle generating circuit is configured to generate a phase shift angle according to the inverter AC terminal voltage and the frequency protection information; wherein the inverter AC terminal voltage and the frequency protection information are respectively moved by the shifting The first input end and the second input end of the phase angle generating circuit reach the phase shift angle generating circuit; the phase shift angle reaches the third input of the phase shifting matrix circuit via the output end of the phase shift angle generating circuit end;
- the phase shifting matrix circuit is configured to use the phase shift angle to And said Performing a phase shift transformation to obtain the And said Wherein And said Receiving, by the first input end and the second input end of the phase shifting matrix circuit, the phase shifting matrix circuit; Receiving, by the first output end of the phase shifting matrix circuit, a first input end of the driving circuit, A second output of the drive circuit is reached via a second output of the phase shifting matrix circuit.
- the phase shift angle generating circuit generates a phase shift angle according to the inverter AC terminal voltage and the frequency protection information; and the phase shift matrix circuit according to the phase shift angle And said Performing a phase shift transformation to obtain the And said ; said And said The driving circuit is configured to generate a driving signal to drive the inverter to output an alternating current voltage having a second frequency; if the second frequency triggers frequency protection, after the operating frequency protection time, the inverter is disconnected from the power grid The connection between the two is out of the island state.
- the phase shift angle generating circuit includes a frequency discriminator, a frequency command generator, and a controller, where:
- the frequency discriminator includes an input end and an output end;
- the frequency command generator includes a first input end, a second output end, and an output end;
- the controller includes a first input end, a second input end, and an output end;
- An output end of the frequency discriminator is connected to a second input end of the frequency command generator and a first input end of the controller; an output end of the frequency command generator is connected to a second input end of the controller ;
- the frequency discriminator is configured to output, according to the voltage of the AC terminal of the inverter, a frequency of the AC voltage of the inverter as a first frequency; wherein, the voltage of the AC terminal of the inverter passes through an input end of the discriminator Arriving at the discriminator; the first frequency is passed through an output end of the discriminator to a second input end of the frequency command generator and a first input end of the controller;
- the frequency command generator is configured to determine a frequency command according to the first frequency and the frequency protection information; wherein the frequency protection information reaches the frequency command generator via a first input end of the frequency command generator; The frequency command reaches the second input end of the controller via an output end of the frequency command generator;
- the controller is configured to determine the phase shift angle according to the first frequency and the frequency instruction; the phase shift angle reaches a third input end of the phase shifting matrix circuit via an output end of the controller.
- the frequency discriminator is configured to output, according to the inverter AC terminal voltage, a frequency of the inverter AC terminal voltage as a first frequency;
- the frequency command generator is configured to use the first frequency according to the first frequency And determining, by the frequency protection information, a frequency command;
- the controller is configured to determine the phase shift angle according to the first frequency and the frequency instruction; and the phase shift matrix circuit according to the phase shift angle And said Performing a phase shift transformation to obtain the And said ;
- the driving circuit is configured to generate a driving signal to drive the inverter to output an alternating current voltage having a second frequency; if the second frequency triggers frequency protection, after the operating frequency protection time, the inverter is disconnected from the power grid The connection between the two is out of the island state.
- the frequency protection information includes an underfrequency protection threshold f min , an underfrequency protection time T 1 , an overfrequency protection threshold f max , and an overfrequency protection time T 2 ;
- the normal operating frequency range is f min ⁇ f max ;
- the frequency command generator is configured to determine a frequency command according to the first frequency and the frequency protection information, including:
- the frequency command generator When the first frequency is within the normal operating frequency range, the frequency command generator outputs the frequency command as the first frequency
- the frequency command generator When the first frequency is not within the normal operating frequency range, and T 1 ⁇ T 2 , the frequency command generator outputs the frequency command as the f min ; when the first frequency is not in the Within the normal operating frequency range, and T 1 > T 2 , the frequency command for outputting the frequency command generator is the f max .
- the frequency command generator sets a frequency protection threshold with a short protection time as a frequency command, causing the inverter output to have a second frequency.
- the second frequency is offset from the frequency protection threshold with a shorter protection time; therefore, if the second frequency triggers the frequency protection, the inverter can disconnect from the grid after a short time of operation. Therefore, in the present embodiment, the inverter can be released from the island state as soon as possible when the islanding effect occurs.
- the driving circuit includes:
- phase locked loop a phase locked loop, a rotary conversion matrix circuit and a drive signal generator
- the phase locked loop includes an input end and an output end;
- the rotation conversion matrix circuit includes a first input end, a second input end, a third input end, and an output end;
- the drive signal generator includes an input end and an output end;
- An output end of the phase locked loop is connected to a third input end of the rotation conversion matrix circuit, and an output end of the rotation conversion matrix circuit is connected to an input end of the driving signal generator;
- the phase-locked loop is configured to obtain phase information of the voltage of the AC terminal of the inverter according to the voltage of the AC terminal of the inverter; wherein, the voltage of the AC terminal of the inverter reaches the input end of the phase-locked loop The phase locked loop; the phase information of the voltage of the AC terminal of the inverter reaches the third input end of the rotation conversion matrix circuit via the output end of the phase locked loop;
- the rotation conversion matrix circuit is configured to: according to phase information of an AC terminal voltage of the inverter And said Converted to a three-phase modulated signal; wherein And said Receiving, by the first input end and the second input end of the rotation conversion matrix circuit, the rotation transformation matrix circuit; the three-phase modulation signal reaches an input of the drive signal generator via an output end of the rotation transformation matrix circuit end;
- the drive signal generator is configured to generate the drive signal according to the three-phase modulation signal; the drive signal reaches the inverter via an output end of the drive signal generator to drive the inverter output to have The second frequency of the alternating voltage, the second frequency is used to control disconnection or maintain a connection between the inverter and the power grid.
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnect from the grid, that is, get out of the island state.
- system further includes:
- a maximum power point tracking unit a DC voltage control unit, an active current control unit, an anti-island strategy unit, and a reactive current control unit;
- the maximum power point tracking unit includes a first input end, a second input end, and an output end;
- the DC voltage control unit includes an input end and an output end;
- the active current control unit includes an input end and an output end;
- the island policy unit includes an output;
- the reactive current control unit includes an input end and an output end;
- An output end of the maximum power point tracking unit is connected to an input end of the DC voltage control unit, an output end of the DC voltage control unit is connected to an input end of the active current control unit, and an output end of the anti-island policy unit Connecting an input end of the reactive current control unit;
- the maximum power point tracking unit is configured to determine a maximum power point voltage output by the new energy power generation module according to the DC voltage and the DC current at the output end of the new energy power generation module; wherein the DC voltage and the DC current pass the maximum power
- the first input end and the second input end of the point tracking unit reach the maximum power point tracking unit; the maximum power point voltage reaches the input end of the DC voltage control unit via the output end of the maximum power point tracking unit;
- the DC voltage control unit is configured to generate an active current command according to the maximum power point voltage; the active current command reaches an input end of the active current control unit via an output end of the DC voltage control unit;
- the active current control unit is configured to generate the active voltage command according to the active current command ; said Receiving, by the output end of the active current control unit, the first input end of the phase shifting loop;
- the anti-island policy unit is configured to generate a reactive current command; the reactive current command reaches an input end of the reactive current control unit via an output end of the anti-island policy unit;
- the reactive current control unit is configured to generate the reactive voltage command according to the reactive current command ; said The output of the reactive current control unit reaches the second input of the phase shifting loop.
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnect from the grid, that is, get out of the island state.
- phase shifting matrix corresponding to the phase shifting matrix circuit is:
- ⁇ is the phase shift angle
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnect from the grid, that is, get out of the island state.
- ⁇ is the phase shift angle
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnected from the grid The connection between the two is out of the island state.
- the inverter is any one of a unidirectional inverter, a three-term inverter, a two-level topology inverter, or a multi-level topology inverter.
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnect from the grid, that is, get out of the island state.
- the controller is any one of a proportional controller, a proportional integral controller, and a proportional differential controller.
- the inverter when the inverter is in an island state, the inverter outputs the AC voltage having the second frequency by using the phase shifting loop, and if the second frequency triggers the frequency protection, the inverter is operated after the frequency protection time. Disconnect from the grid, that is, get out of the island state.
- the phase shifting loop can be used to offset the frequency of the AC terminal voltage of the inverter to the second frequency, so that the frequency is triggered.
- the frequency protection thus disconnects from the grid, ie out of the island state.
- FIG. 1 is a schematic structural diagram of an inverter anti-island control system according to an embodiment of the present invention
- FIG. 2 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- FIG. 3 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- FIG. 4 is a schematic flowchart of determining a frequency instruction according to an embodiment of the present invention.
- FIG. 5 is a schematic diagram of signal flow in the inverter anti-island control system disclosed in FIG. 3;
- 6a is a waveform diagram of an island detecting experiment without using the inverter anti-islanding control system disclosed in FIG. 3;
- 6b is a waveform diagram of an island detecting experiment using the inverter anti-islanding control system disclosed in FIG. 3;
- FIG. 7 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- FIG. 8 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- Embodiments of the present invention provide an inverter anti-island control system, which is applicable to various grid-connected inverters, and may be a single-phase inverter, a three-phase inverter, a two-level topology inverter, or multiple power
- the embodiment of the present invention is not limited in the embodiment of the present invention.
- the phase shifting loop when the inverter is in an island state, the phase shifting loop is used to shift the frequency of the AC terminal voltage of the inverter to the second frequency, so that the frequency protection is triggered to disconnect the connection with the power grid. That is to get out of the island state. The details are described below separately.
- FIG. 1 is a schematic structural diagram of an inverter anti-island control system according to an embodiment of the present invention.
- the inverter anti-island control system described in this embodiment includes a phase shifting loop 10 and a driving circuit 20, wherein:
- the phase shifting ring 10 includes a first input terminal 11, a second input terminal 12, a third input terminal 13, a fourth input terminal 14, a first output terminal 15 and a second output terminal 16;
- the drive circuit 20 includes a first input terminal 21 The second input terminal 22, the third input terminal 23 and the output terminal 24.
- the first output 15 of the phase shifting ring 10 is connected to the first input 21 of the drive circuit 20, and the second output 16 of the phase shifting ring 10 is connected to the second input 22 of the drive circuit 20.
- the phase shifting loop 10 sets the active voltage command according to the voltage of the AC terminal of the inverter and the frequency protection information in the grid-connected standard. And reactive voltage command Perform phase shift conversion to obtain the active voltage command after phase shifting Reactive voltage command after phase shifting ;among them,
- the frequency protection information in the inverter AC terminal voltage and the grid-connected standard reaches the phase shift loop via the first input terminal 11, the second input terminal 12, the third input terminal 13 and the fourth input terminal 14 of the phase shifting ring 10, respectively. 10;
- the first output 15 of the phase shifting loop 10 reaches the first input 21 of the drive circuit 20,
- the second output 16 of the phase shifting loop 10 reaches the second input 22 of the drive circuit 20.
- the driving circuit 20 is based on with Generating a drive signal; the drive signal reaches the inverter via the output 23 of the drive circuit 20 to drive the inverter to output an AC voltage having a second frequency, and the second frequency is used to control disconnection or maintain between the inverter and the grid Connection.
- the frequency protection information of the Grid Code contains underfrequency protection threshold f min, under-frequency protection time T 1, overfrequency threshold value f max and overfrequency time T 2, if the second frequency is lower than f min , triggers the underfrequency protection.
- the T 1 time is run, that is, the connection between the inverter and the grid is disconnected; if the second frequency is higher than f max , the overfrequency protection is triggered.
- the T 2 time is operated, that is, the connection between the inverter and the grid is disconnected; if the second frequency is in the range of f min ⁇ f max , the connection between the inverter and the grid is maintained.
- the new energy equipment When new energy is connected to the grid, for example, the new energy equipment is a photovoltaic array, and the generated electric energy is supplied to the grid or the load through a system that constitutes a photovoltaic array, an inverter, a transformer, a load, and a power grid.
- the photovoltaic array generates DC power
- the inverter converts the DC power into AC power
- the AC power is boosted by the transformer and transmitted to the power grid.
- the inverter fails to detect the power failure state of the grid and cuts itself off the grid. Instead, it supplies power to the load as an isolated power source, that is, the inverter has an island state.
- the phase shifting loop can be used to offset the frequency of the AC terminal voltage of the inverter to the second frequency, so that the frequency is triggered.
- the frequency protection thus disconnects from the grid, ie out of the island state.
- FIG. 2 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- the inverter anti-island control system described in this embodiment includes a phase shifting loop 10 and a driving circuit 20, wherein:
- the phase shifting ring 10 includes a first input terminal 11, a second input terminal 12, a third input terminal 13, a fourth input terminal 14, a first output terminal 15 and a second output terminal 16;
- the drive circuit 20 includes a first input terminal 21 The second input terminal 22, the third input terminal 23 and the output terminal 24.
- the first output 15 of the phase shifting loop 10 is connected to the first input 21 of the drive circuit 20 and the second output of the phase shifting loop 10
- the terminal 16 is connected to the second input 22 of the drive circuit 20.
- the phase shifting loop 10 includes a phase shifting angle generating circuit 101 and a phase shifting matrix circuit 102, wherein:
- the phase shifting angle generating circuit 101 includes a first input terminal 111, a second input terminal 121, and an output terminal 131.
- the phase shifting matrix circuit 102 includes a first input terminal 112, a second input terminal 122, a third input terminal 132, and a first output. End 142 and second output 152.
- the output 131 of the phase shift angle generating circuit 101 is coupled to the third input terminal 132 of the phase shift matrix circuit 102.
- the phase shift angle generating circuit 101 generates a phase shift angle according to the voltage of the inverter AC terminal and the frequency protection information in the grid-connected standard; wherein the inverter AC terminal voltage and the frequency protection information are respectively first through the phase shift angle generating circuit 101
- the input terminal 111 and the second input terminal 121 reach the phase shift angle generating circuit 101; the phase shift angle reaches the third input terminal 132 of the phase shift matrix circuit 102 via the output terminal 131 of the phase shift angle generating circuit 101.
- the phase shifting matrix circuit 102 will have an active voltage command according to the phase shift angle And reactive voltage command Perform phase shifting to obtain the active voltage command after phase shifting Reactive voltage command after phase shifting ;among them, with
- the first input terminal 112 and the second input terminal 122 of the phase shifting matrix circuit 102 respectively reach the phase shifting matrix circuit 102;
- the first output terminal 142 of the phase shifting matrix circuit 102 reaches the first input terminal 21 of the driving circuit 20,
- the second output 152 of the phase shifting matrix circuit 102 reaches the second input 22 of the drive circuit 20.
- phase shifting matrix corresponding to the phase shifting matrix circuit 102 is:
- ⁇ is the phase shift angle
- the phase shifting loop can be used to offset the frequency of the AC terminal voltage of the inverter to the second frequency, so that the frequency is triggered.
- the frequency protection thus disconnects from the grid, ie out of the island state.
- FIG. 3 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- the inverter anti-island control system described in this embodiment includes a phase shifting loop 10 and a driving circuit 20, wherein:
- the phase shifting ring 10 includes a first input terminal 11, a second input terminal 12, a third input terminal 13, a fourth input terminal 14, a first output terminal 15 and a second output terminal 16;
- the drive circuit 20 includes a first input terminal 21 The second input terminal 22, the third input terminal 23 and the output terminal 24.
- the first output 15 of the phase shifting ring 10 is connected to the first input 21 of the drive circuit 20, and the second output 16 of the phase shifting ring 10 is connected to the second input 22 of the drive circuit 20.
- the phase shifting loop 10 includes a phase shifting angle generating circuit 101 and a phase shifting matrix circuit 102, wherein:
- the phase shifting angle generating circuit 101 includes a first input terminal 111, a second input terminal 121, and an output terminal 131.
- the phase shifting matrix circuit 102 includes a first input terminal 112, a second input terminal 122, a third input terminal 132, and a first output. End 142 and second output 152.
- the output 131 of the phase shift angle generating circuit 101 is coupled to the third input terminal 132 of the phase shift matrix circuit 102.
- the phase shift angle generating circuit 101 includes a frequency discriminator 1011, a frequency command generator 1012, and a controller 1013, wherein:
- the frequency discriminator 1011 includes an input terminal 1111 and an output terminal 1211.
- the frequency command generator 1012 includes a first input terminal 1112, a second output terminal 1212, and an output terminal 1312.
- the controller 1013 includes a first input terminal 1113 and a second input terminal 1213. And an output 1313.
- the output terminal 1211 of the frequency discriminator 1011 is connected to the second input terminal 1212 of the frequency command generator 1012 and the first input terminal 1113 of the controller 1013; the output terminal 1312 of the frequency command generator 1012 is connected to the second input terminal 1213 of the controller 1013. .
- the frequency discriminator 1011 outputs the frequency of the AC terminal voltage of the inverter as the first frequency according to the voltage of the AC terminal of the inverter; wherein, the voltage of the AC terminal of the inverter reaches the discriminator 1011 via the input end 1111 of the discriminator 1011; The frequency reaches the second input 1212 of the frequency command generator 1012 and the first input 1113 of the controller 1013 via the output 1211 of the frequency discriminator 1011.
- the frequency command generator 1012 determines the frequency command according to the frequency protection information in the first frequency and the grid-connected standard; wherein the frequency protection information reaches the frequency command generator 1012 via the first input terminal 1112 of the frequency command generator 1012; The output 1312 of the command generator 1012 reaches the second input 1213 of the controller 1013.
- the frequency protection information comprising underfrequency protection threshold f min, under-frequency protection time T 1, overfrequency threshold value f max and overfrequency time T 2, the normal operating frequency range f min ⁇ f max.
- the frequency command output by the frequency command generator 1012 is the first frequency; when the first frequency is not within the normal operating frequency range, and T 1 ⁇ T 2 , the frequency command generator 1012 outputs The frequency command is f min ; when the first frequency is not within the normal operating frequency range, and T 1 >T 2 , the frequency command output by the frequency command generator 1012 is f max .
- the frequency command generator sets the frequency protection threshold with a short protection time as the frequency command, causing the inverter to output the alternating voltage with the second frequency, the second The frequency is offset to a frequency protection threshold with a short protection time; therefore, if the second frequency triggers the frequency protection, the inverter can disconnect from the power grid after a short time of operation, so in this embodiment, When the inverter is in an islanding effect, it will leave the island state as soon as possible.
- the frequency protection information includes an underfrequency protection threshold f min , an underfrequency protection time T 1 , an overfrequency protection threshold f max , and an overfrequency protection time T 2
- the normal operating frequency range is k 1 f min ⁇ k 2 f max , where k 1 is greater than 1, k 2 is less than 1, and k 1 f min ⁇ k 2 f max such that the normal operating frequency range is less than the range of f min ⁇ f max .
- k 1 can be 1.1 and k 2 can be 0.9.
- the frequency command output by the frequency command generator 1012 is the first frequency; when the first frequency is not within the normal operating frequency range, and T 1 ⁇ T 2 , the frequency command generator 1012 outputs The frequency command is f min ; when the first frequency is not within the normal operating frequency range, and T 1 >T 2 , the frequency command output by the frequency command generator 1012 is f max .
- FIG. 4 is a schematic flow chart of a frequency command generator determining a frequency command.
- the frequency command f * is set to f min ; when T 1 ⁇ T 2 and f>k 1 f min , the frequency command f * is set to the first frequency f;
- the frequency command is set to f max ; when T 1 >T 2 and f ⁇ k 2 f min , the frequency command is set to the first frequency f.
- the controller 1013 determines a phase shift angle based on the first frequency and the frequency command; the phase shift angle reaches the third input 132 of the phase shift matrix circuit 102 via the output 1313 of the controller 1013.
- the controller 1013 can be a proportional controller, a proportional integral controller, a proportional differential controller, etc., for example, in the embodiment of the present invention, the controller 1013 is a proportional product. Sub-controller.
- FIG. 5 is a schematic diagram of signal flow in the inverter anti-island system depicted in FIG.
- the frequency discriminator outputs the frequency of the inverter AC terminal voltage as the first frequency f according to the inverter AC terminal voltage e abc ;
- the frequency command generator reads the grid connection
- the frequency protection information in the standard determines the frequency command according to the underfrequency protection threshold f min , the underfrequency protection time T 1 , the overfrequency protection threshold f max and the overfrequency protection time T 2 and the first frequency f in the frequency protection information.
- the controller outputs a phase shift angle ⁇ according to the above frequency command and the first frequency;
- the island phase shift matrix circuit changes the active voltage command output by the active current control unit and the reactive current control unit according to the phase shift angle ⁇ And reactive voltage command , output active voltage command after phase shift Reactive voltage command after phase shifting ;
- drive circuit according to the above Above Generating a drive signal with the inverter AC terminal voltage e abc to drive the inverter to output an AC voltage having a second frequency, wherein the second frequency is offset from the first frequency to a frequency protection threshold having a shorter guard time; If the second frequency triggers underfrequency protection or overfrequency protection, the inverter disconnects from the grid after running under the underfrequency/overfrequency protection time, that is, it is separated from the island power generation system.
- FIG. 6a is a schematic diagram of waveforms for island detection without using the inverter anti-island control system disclosed in FIG. 3; as shown in FIG. 6a, the waveforms of the first to third channels are waveforms of the inverter three-phase output current, and the fourth is The waveform of the road is the waveform of the current detected at the grid-connected switch; when the grid-connected switch is turned off at time b, the current drop detected at the grid-connected switch is 0, that is, the islanding effect occurs; at a time, the inverter is disconnected from the grid.
- FIG. 6b is a waveform diagram of an island detection experiment using the inverter anti-island control system disclosed in FIG.
- the waveforms of 1 to 3 in the figure are the waveforms of the three-phase output current of the inverter
- the waveform of the fourth channel is the waveform of the current detected at the grid-connected switch
- the current drop detected at the switch is 0, that is, the islanding effect occurs
- the inverter is disconnected from the grid, and the three-phase output current is reduced to 0, that is, the island state is removed.
- the frequency command generator sets the frequency protection threshold with a short protection time as the frequency command, causing the inverter to output the alternating voltage with the second frequency, the second The frequency is offset to a frequency protection threshold with a short protection time; therefore, if the second frequency triggers the frequency protection, the inverter can disconnect from the power grid after a short time of operation, so in this embodiment, When the inverter is in an islanding effect, it will leave the island state as soon as possible.
- FIG. 7 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- the inverter anti-island control system described in this embodiment includes a phase shifting loop 10 and a driving circuit 20, wherein:
- the phase shifting ring 10 includes a first input terminal 11, a second input terminal 12, a third input terminal 13, a fourth input terminal 14, a first output terminal 15 and a second output terminal 16;
- the drive circuit 20 includes a first input terminal 21 The second input terminal 22, the third input terminal 23 and the output terminal 24.
- the first output 15 of the phase shifting loop 10 is connected to the first input 21 of the drive circuit 20 and the second output of the phase shifting loop 10
- the terminal 16 is connected to the second input 22 of the drive circuit 20.
- the phase shifting loop 10 includes a phase shifting angle generating circuit 101 and a phase shifting matrix circuit 102, wherein:
- the phase shifting angle generating circuit 101 includes a first input terminal 111, a second input terminal 121, and an output terminal 131.
- the phase shifting matrix circuit 102 includes a first input terminal 112, a second input terminal 122, a third input terminal 132, and a first output. End 142 and second output 152.
- the output 131 of the phase shift angle generating circuit 101 is coupled to the third input terminal 132 of the phase shift matrix circuit 102.
- the phase shift angle generating circuit 101 includes a frequency discriminator 1011, a frequency command generator 1012, and a controller 1013, wherein:
- the frequency discriminator 1011 includes an input terminal 1111 and an output terminal 1211.
- the frequency command generator 1012 includes a first input terminal 1112, a second output terminal 1212, and an output terminal 1312.
- the controller 1013 includes a first input terminal 1113 and a second input terminal 1213. And an output 1313.
- the output terminal 1211 of the frequency discriminator 1011 is connected to the second input terminal 1212 of the frequency command generator 1012 and the first input terminal 1113 of the controller 1013; the output terminal 1312 of the frequency command generator 1012 is connected to the second input terminal 1213 of the controller 1013. .
- the above drive circuit 20 includes a phase locked loop 201, a rotation conversion matrix circuit 202, and a drive signal generator 203.
- the phase locked loop 201 includes an input end 211 and an output end 221;
- the rotation conversion matrix circuit 202 includes a first input end 212, a second input end 222, a third input end 232 and an output end 242;
- the drive signal generator 203 includes an input end 213 And output terminal 223.
- the output terminal 221 of the phase locked loop 201 is connected to the third input terminal 232 of the rotary conversion matrix circuit 202, and the output terminal 242 of the rotary conversion matrix circuit 202 is connected to the input terminal 213 of the drive signal generator 203.
- the phase-locked loop 201 obtains phase information of the voltage of the AC terminal of the inverter according to the voltage of the AC terminal of the inverter; wherein, the voltage of the AC terminal of the inverter reaches the phase-locked loop 201 via the input end 211 of the phase-locked loop 201; The phase information of the terminal voltage reaches the third input 232 of the rotary conversion matrix circuit 202 via the output 221 of the phase locked loop 201.
- the rotation transformation matrix circuit 202 will according to the phase information of the voltage of the AC terminal of the inverter. with Converted to a three-phase modulated signal; And above The first input terminal 212 and the second input terminal 222 of the rotary conversion matrix circuit 202 arrive at the rotation transformation matrix circuit 202; the three-phase modulation signal passes through the output of the rotation conversion matrix circuit 202 to the input terminal 213 of the drive signal generator 203.
- the driving signal generator 203 generates a driving signal according to the above-mentioned three-phase modulation signal; the driving signal reaches the inverter through the output terminal 223 of the driving signal generator 203 to drive the inverter to output the alternating current voltage having the second frequency, and the second frequency is used for the second frequency. Control the disconnection or maintain the connection between the inverter and the grid.
- the phase shifting loop can be used to offset the frequency of the AC terminal voltage of the inverter to the second frequency, so that the frequency is triggered.
- the frequency protection thus disconnects from the grid, ie out of the island state.
- FIG. 8 is a schematic structural diagram of another inverter anti-island control system according to an embodiment of the present invention.
- the inverter anti-island control system described in this embodiment includes a phase shifting loop 10 and a driving circuit 20, wherein:
- the phase shifting ring 10 includes a first input terminal 11, a second input terminal 12, a third input terminal 13, a fourth input terminal 14, a first output terminal 15 and a second output terminal 16;
- the drive circuit 20 includes a first input terminal 21 , the second input terminal 22, the third input Incoming terminal 23 and output terminal 24.
- the first output 15 of the phase shifting ring 10 is connected to the first input 21 of the drive circuit 20, and the second output 16 of the phase shifting ring 10 is connected to the second input 22 of the drive circuit 20.
- the phase shifting loop 10 includes a phase shifting angle generating circuit 101 and a phase shifting matrix circuit 102, wherein:
- the phase shifting angle generating circuit 101 includes a first input terminal 111, a second input terminal 121, and an output terminal 131.
- the phase shifting matrix circuit 102 includes a first input terminal 112, a second input terminal 122, a third input terminal 132, and a first output. End 142 and second output 152.
- the output 131 of the phase shift angle generating circuit 101 is coupled to the third input terminal 132 of the phase shift matrix circuit 102.
- the phase shift angle generating circuit 101 includes a frequency discriminator 1011, a frequency command generator 1012, and a controller 1013, wherein:
- the frequency discriminator 1011 includes an input terminal 1111 and an output terminal 1211.
- the frequency command generator 1012 includes a first input terminal 1112, a second output terminal 1212, and an output terminal 1312.
- the controller 1013 includes a first input terminal 1113 and a second input terminal 1213. And an output 1313.
- the output terminal 1211 of the frequency discriminator 1011 is connected to the second input terminal 1212 of the frequency command generator 1012 and the first input terminal 1113 of the controller 1013; the output terminal 1312 of the frequency command generator 1012 is connected to the second input terminal 1213 of the controller 1013. .
- the above drive circuit 20 includes a phase locked loop 201, a rotation conversion matrix circuit 202, and a drive signal generator 203.
- the phase locked loop 201 includes an input end 211 and an output end 221;
- the rotation conversion matrix circuit 202 includes a first input end 212, a second input end 222, a third input end 232 and an output end 242;
- the drive signal generator 203 includes an input end 213 And output terminal 223.
- the output terminal 221 of the phase locked loop 201 is connected to the third input terminal 232 of the rotary conversion matrix circuit 202, and the output terminal 242 of the rotary conversion matrix circuit 202 is connected to the input terminal 213 of the drive signal generator 203.
- the inverter anti-island control system further includes:
- the maximum power point tracking unit 30 the DC voltage control unit 40, the active current control unit 50, the anti-island policy unit 60, and the reactive current control unit 70.
- the maximum power point tracking unit 30 includes a first input terminal 31, a second input terminal 32, and an output terminal 33.
- the DC voltage control unit 40 includes an input terminal 41 and an output terminal 42.
- the active current control unit 50 includes an input terminal 51 and an output terminal 52.
- the anti-island policy unit 60 includes an output 61; the reactive current control unit 70 includes an input 71 and an output 72.
- the output 33 of the maximum power point tracking unit 30 is connected to the input 41 of the DC voltage control unit 40, the output 42 of the DC voltage control unit 40 is connected to the input 51 of the active current control unit 50, and the output 61 of the anti-island policy unit 60 The input 71 of the reactive current control unit 70 is connected.
- the maximum power point tracking unit 30 determines the maximum power point voltage output by the new energy power generation module according to the DC voltage and the DC current at the output end of the new energy power generation module; wherein the DC voltage and the DC current pass through the first input end of the maximum power point tracking unit 30. 31 and the second input 32 arrive at the maximum power point tracking unit 30; the maximum power point voltage reaches the input 41 of the DC voltage control unit 40 via the output 33 of the maximum power point tracking unit 30.
- the DC voltage control unit 40 generates an active current command based on the maximum power point voltage; the active current command reaches the input 51 of the active current control unit 50 via the output 42 of the DC voltage control unit 40.
- the active current control unit 50 generates an active voltage command according to the active current command ;
- the output 52 of the active current control unit 50 reaches the first input 11 of the phase shifting loop 10.
- the anti-island policy unit 60 is configured to generate a reactive current command; the reactive current command reaches the input 71 of the reactive current control unit 70 via the output 61 of the anti-islanding strategy unit 60.
- the reactive current control unit 70 is configured to generate a reactive voltage command according to the reactive current command ;
- the output 72 of the reactive current control unit 70 reaches the second input 12 of the phase shifting loop 10.
- the phase shifting loop can be used to offset the frequency of the AC terminal voltage of the inverter to the second frequency, so that the frequency is triggered.
- the frequency protection thus disconnects from the grid, ie out of the island state.
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Abstract
一种逆变器反孤岛控制***,包括移相环(10)和驱动电路(20),该移相环(10)包括第一输入端(11)、第二输入端(12)、第三输入端(13)、第四输入端(14)、第一输出端(15)和第二输出端(16);该驱动电路(20)包括第一输入端(21)、第二输入端(22)、第三输入端(23)和输出端(24);移相环(10)的第一输出端(15)连接驱动电路(20)的第一输入端(21),移相环(10)的第二输出端(16)连接驱动电路(20)的第二输入端(22)。该逆变器反孤岛控制***,可以当逆变器出现孤岛状态时,利用移相环(10)使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
Description
本发明涉及电力***自动化技术领域,尤其涉及一种逆变器反孤岛控制***。
新能源并网发电时产生直流电能,需要通过逆变器将直流电能转换为交流电能,再向主电网和负载供电。逆变器的孤岛状态是指,当并网开关跳闸时,逆变器未能检出主电网的停电状态将自身切离电网,而是作为孤立电源对负载进行供电。
孤岛状态对设备和人员的安全存在重大隐患:当检修人员停止主电网的供电,对电力线路和电路设备进行检修时,若新能源的逆变器仍然继续为负载供电,会造成检修人员的伤亡事故;除此以外,若并网的逆变器保持供电,当主电网恢复供电后,电网电压和逆变器的输出电压在相位上可能存在较大差异,在瞬间产生很大的冲击电流从而损坏设备。
因此,需要通过孤岛检测策略,利用通讯或外设、被动式检测、主动式扰动等方法,检测出孤岛状态,并使逆变器脱离孤岛发电***。然而,上述孤岛检测策略,通常依赖于过/欠压或过/欠频保护机制,当逆变器的过/欠压或过/欠频保护时间,大于并网标准要求的孤岛保护时间时,就会出现孤岛检测失败的情况。
因此,如何在主电网断电时检测出逆变器的孤岛状态以将逆变器切离电网,成为一个亟待解决的问题。
发明内容
本发明实施例提供了一种逆变器反孤岛控制***,可以当逆变器出现孤岛状态时,利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
本发明实施例公开了一种逆变器反孤岛控制***,包括:
移相环和驱动电路;
所述移相环包括第一输入端、第二输入端、第三输入端、第四输入端、第一输出端和第二输出端;所述驱动电路包括第一输入端、第二输入端、第三输入端和输出端;
所述移相环的第一输出端连接所述驱动电路的第一输入端,所述移相环的第二输出端连接所述驱动电路的第二输入端;
所述移相环用于根据所述逆变器交流端电压和并网标准中的频率保护信息,将有功电压指令和无功电压指令进行移相变换,得到移相后的有功电压指令和移相后的无功电压指令;其中,所述、所述、所述逆变器交流端电压和所述并网标准中的频率保护信息分别经所述移相环的第一输入端、第二输入端、第三输入端和第四输入端到达所述移相环;所述经所述移相环的第一输出端到达所述驱动电路的第一输入端,所述经所述移相环的第二输出端到达所述驱动电路的第二输入端;
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述移相环包括移相角产生电路和移相矩阵电路,其中:
所述移相角产生电路包括第一输入端、第二输入端和输出端;所述移相矩阵电路包括第一输入端、第二输入端、第三输入端、第一输出端和第二输出端;
所述移相角产生电路的输出端连接所述移相矩阵电路的第三输入端;
所述移相角产生电路用于根据所述逆变器交流端电压和所述频率保护信息产生移相角;其中,所述逆变器交流端电压和所述频率保护信息分别经所述移相角产生电路的第一输入端和第二输入端到达所述移相角产生电路;所述移相角经所述移相角产生电路的输出端到达所述移相矩阵电路的第三输入端;
所述移相矩阵电路用于根据所述移相角将所述和所述进行移相变换得到所述和所述;其中,所述和所述分别经所述移相矩阵电路的第一输入端和第二输入端到达所述移相矩阵电路;所述经所述移相矩阵电路的第一输出端到达所述驱动电路的第一输入端,所述经所述移相矩阵电路的第二输出端到达所述驱动电路的第二输入端。
在该实施方式中,移相角产生电路根据所述逆变器交流端电压和所述频率保护信息产生移相角;移相矩阵电路根据所述移相角,将所述和所述进行移相变换得到所述和所述;所述和所述用以使所述驱动电路产生驱动信号,以驱动所述逆变器输出具有第二频率的交流电压;若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述移相角产生电路包括鉴频器、频率指令发生器和控制器,其中:
所述鉴频器包括输入端和输出端;所述频率指令发生器包括第一输入端、第二输出端和输出端;所述控制器包括第一输入端、第二输入端和输出端;
所述鉴频器的输出端连接所述频率指令发生器的第二输入端和所述控制器的第一输入端;所述频率指令发生器的输出端连接所述控制器的第二输入端;
所述鉴频器用于根据所述逆变器交流端电压输出所述逆变器交流端电压的频率作为第一频率;其中,所述逆变器交流端电压经所述鉴频器的输入端到达所述鉴频器;所述第一频率经所述鉴频器的输出端到达所述频率指令发生器的第二输入端和所述控制器的第一输入端;
所述频率指令发生器用于根据所述第一频率和所述频率保护信息确定频率指令;其中,所述频率保护信息经所述频率指令发生器的第一输入端到达所述频率指令发生器;所述频率指令经所述频率指令发生器的输出端到达所述控制器的第二输入端;
所述控制器用于根据所述第一频率和所述频率指令确定所述移相角;所述移相角经所述控制器的输出端到达所述移相矩阵电路的第三输入端。
在该实施方式中,所述鉴频器用于根据所述逆变器交流端电压输出所述逆变器交流端电压的频率作为第一频率;所述频率指令发生器用于根据所述第一频率和所述频率保护信
息确定频率指令;所述控制器用于根据所述第一频率和所述频率指令确定所述移相角;移相矩阵电路根据所述移相角,将所述和所述进行移相变换得到所述和所述;所述和所述用以使所述驱动电路产生驱动信号,以驱动所述逆变器输出具有第二频率的交流电压;若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述频率保护信息包括欠频保护阈值fmin、欠频保护时间T1、过频保护阈值fmax和过频保护时间T2;
正常工作频率范围为fmin~fmax;
所述频率指令发生器用于根据所述第一频率和所述频率保护信息确定频率指令,包括:
当所述第一频率在所述正常工作频率范围内,所述频率指令发生器用于输出的所述频率指令为所述第一频率;
当所述第一频率不在所述正常工作频率范围内,且T1<T2,所述频率指令发生器用于输出的所述频率指令为所述fmin;当所述第一频率不在所述正常工作频率范围内,且T1>T2,所述频率指令发生器用于输出的所述频率指令为所述fmax。
在该实施方式中,当所述第一频率不在所述正常工作频率范围内,频率指令发生器将保护时间短的频率保护阈值设定为频率指令,导致所述逆变器输出具有第二频率的交流电压时,第二频率向保护时间较短的频率保护阈值偏移;因此,若第二频率触发频率保护,则运行较短时间之后,逆变器便能断开与电网之间的连接,因此本实施方式,可以使逆变器在发生孤岛效应时,尽快脱离孤岛状态。
作为一种可选的实施方式,所述驱动电路包括:
锁相环、旋转变换矩阵电路和驱动信号发生器;
所述锁相环包括输入端和输出端;所述旋转变换矩阵电路包括第一输入端、第二输入端、第三输入端和输出端;所述驱动信号发生器包括输入端和输出端;
所述锁相环的输出端连接所述旋转变换矩阵电路的第三输入端,所述旋转变换矩阵电路的输出端连接所述驱动信号发生器的输入端;
所述锁相环用于根据所述逆变器交流端电压,获得所述逆变器交流端电压的相位信息;其中,所述逆变器交流端电压经所述锁相环的输入端到达所述锁相环;所述逆变器交流端电压的相位信息经所述锁相环的输出端到达所述旋转变换矩阵电路的第三输入端;
所述旋转变换矩阵电路用于根据所述逆变器交流端电压的相位信息,将所述和所述转换为三相调制信号;其中,所述和所述经所述旋转变换矩阵电路的第一输入端和第二输入端到达所述旋转变换矩阵电路;所述三相调制信号经所述旋转变换矩阵电路的输出端到达所述驱动信号发生器的输入端;
所述驱动信号发生器用于根据所述三相调制信号产生所述驱动信号;所述驱动信号经所述驱动信号发生器的输出端到达所述逆变器,以驱动所述逆变器输出具有所述第二频率的交流电压,所述第二频率用于控制断开或保持所述逆变器与电网之间的连接。
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述***还包括:
最大功率点跟踪单元、直流电压控制单元、有功电流控制单元、反孤岛策略单元和无功电流控制单元;
所述最大功率点跟踪单元包括第一输入端、第二输入端和输出端;所述直流电压控制单元包括输入端和输出端;所述有功电流控制单元包括输入端和输出端;所述反孤岛策略单元包括输出端;所述无功电流控制单元包括输入端和输出端;
所述最大功率点跟踪单元的输出端连接所述直流电压控制单元的输入端,所述直流电压控制单元的输出端连接所述有功电流控制单元的输入端,所述反孤岛策略单元的输出端连接所述无功电流控制单元的输入端;
所述最大功率点跟踪单元用于根据新能源发电模块输出端的直流电压和直流电流,确定新能源发电模块输出的最大功率点电压;其中,所述直流电压和所述直流电流经所述最大功率点跟踪单元的第一输入端和第二输入端到达所述最大功率点跟踪单元;所述最大功率点电压经所述最大功率点跟踪单元的输出端到达所述直流电压控制单元的输入端;
所述直流电压控制单元用于根据所述最大功率点电压产生有功电流指令;所述有功电流指令经所述直流电压控制单元的输出端到达所述有功电流控制单元的输入端;
所述反孤岛策略单元用于产生无功电流指令;所述无功电流指令经所述反孤岛策略单元的输出端到达所述无功电流控制单元的输入端;
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述移相矩阵电路所对应的移相矩阵为:
其中Δθ为所述移相角。
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
其中Δθ为所述移相角。
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之
间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述逆变器为单向逆变器、三项逆变器、两电平拓扑逆变器或多电平拓扑逆变器中的任意一种。
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
作为一种可选的实施方式,所述控制器为比例控制器、比例积分控制器、比例微分控制器中的任意一种。
在该实施方式中,当逆变器出现孤岛状态时,利用移相环使逆变器输出具有第二频率的交流电压,若第二频率触发频率保护,则运行频率保护时间之后,逆变器断开与电网之间的连接,即脱离孤岛状态。
从以上技术方案可以看出,本发明实施例具有以下优点:
当逆变器出现孤岛状态时,逆变器交流端电压的频率偏离正常工作范围,本发明实施例可以利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
图1是本发明实施例公开的一种逆变器反孤岛控制***的结构示意图;
图2是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图;
图3是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图;
图4为本发明实施例公开的一种确定频率指令的流程示意图;
图5为图3所公开的逆变器反孤岛控制***中信号流向示意图;
图6a为未利用图3所公开的逆变器反孤岛控制***进行孤岛检测实验的波形示意图;
图6b为利用图3所公开的逆变器反孤岛控制***进行孤岛检测实验的波形示意图;
图7是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图;
图8是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图。
本发明的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别不同的对象,而不是用于描述特定顺序。此外,术语“包括”和“具有”以及它们任何变形,意图在于覆盖不排他的包含。例如包含了一系列步骤或单元的过程、方法、***、产品或设备没有限定于已列出的步骤或单元,而是可选地还包括没有列出的步骤或单元,或可选地还包括对于这些过程、方法或设备固有的其他步骤或单元。
本发明实施例提供了一种逆变器反孤岛控制***,适用于各种并网逆变器,可以是单相逆变器、三相逆变器、两电平拓扑逆变器或多电平拓扑逆变器等,具体应用于何种逆变器,本发明实施例不做限制。本发明实施例可以当逆变器出现孤岛状态时,利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,
即脱离孤岛状态。以下分别进行详细说明。
请参阅图1,图1是本发明实施例公开的一种逆变器反孤岛控制***的结构示意图。如图1所示,本实施例中所描述的逆变器反孤岛控制***,包括移相环10和驱动电路20,其中:
移相环10包括第一输入端11、第二输入端12、第三输入端13、第四输入端14、第一输出端15和第二输出端16;驱动电路20包括第一输入端21、第二输入端22、第三输入端23和输出端24。
移相环10的第一输出端15连接驱动电路20的第一输入端21,移相环10的第二输出端16连接驱动电路20的第二输入端22。
本发明实施例中,移相环10根据逆变器交流端电压和并网标准中的频率保护信息,将有功电压指令和无功电压指令进行移相变换,得到移相后的有功电压指令和移相后的无功电压指令;其中,、逆变器交流端电压和并网标准中的频率保护信息分别经移相环10的第一输入端11、第二输入端12、第三输入端13和第四输入端14到达移相环10;经移相环10的第一输出端15到达驱动电路20的第一输入端21,经移相环10的第二输出端16到达驱动电路20的第二输入端22。
本发明实施例中,上述并网标准中的频率保护信息包含欠频保护阈值fmin、欠频保护时间T1、过频保护阈值fmax和过频保护时间T2,若第二频率低于fmin,则触发欠频频率保护,触发欠频频率保护之后运行T1时间,即断开逆变器与电网之间的连接;若第二频率高于fmax,则触发过频频率保护,触发过频频率保护之后运行T2时间,即断开逆变器与电网之间的连接;若第二频率在fmin~fmax范围内,则保持逆变器与电网之间的连接。
新能源并网发电时,举例来说,新能源设备为光伏阵列,则通过组成光伏阵列、逆变器、变压器、负载及电网的***来将产生的电能供给至电网或者负载。其中,光伏阵列产生直流电能,逆变器将直流电能转换成交流电能,交流电能经变压器升压后,传递到电网。当电网断电时,逆变器未能检出电网的停电状态将自身切离电网,而是作为孤立电源对负载进行供电,即逆变器出现孤岛状态。
当逆变器出现孤岛状态时,逆变器交流端电压的频率偏离正常工作范围,本发明实施例可以利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
请参阅图2,图2是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图。如图2所示,本实施例中所描述的逆变器反孤岛控制***,包括移相环10和驱动电路20,其中:
移相环10包括第一输入端11、第二输入端12、第三输入端13、第四输入端14、第一输出端15和第二输出端16;驱动电路20包括第一输入端21、第二输入端22、第三输入端23和输出端24。
移相环10的第一输出端15连接驱动电路20的第一输入端21,移相环10的第二输出
端16连接驱动电路20的第二输入端22。
移相环10包括移相角产生电路101和移相矩阵电路102,其中:
移相角产生电路101包括第一输入端111、第二输入端121和输出端131;移相矩阵电路102包括第一输入端112、第二输入端122、第三输入端132、第一输出端142和第二输出端152。
移相角产生电路101的输出端131连接移相矩阵电路102的第三输入端132。
移相角产生电路101根据逆变器交流端电压和并网标准中的频率保护信息产生移相角;其中,逆变器交流端电压和频率保护信息分别经移相角产生电路101的第一输入端111和第二输入端121到达移相角产生电路101;移相角经移相角产生电路101的输出端131到达移相矩阵电路102的第三输入端132。
移相矩阵电路102根据移相角将有功电压指令和无功电压指令进行移相变换得到移相后的有功电压指令和移相后的无功电压指令;其中,和分别经移相矩阵电路102的第一输入端112和第二输入端122到达移相矩阵电路102;经移相矩阵电路102的第一输出端142到达驱动电路20的第一输入端21,经移相矩阵电路102的第二输出端152到达驱动电路20的第二输入端22。
进一步地,移相矩阵电路102所对应的移相矩阵为:
,其中Δθ为移相角。
当逆变器出现孤岛状态时,逆变器交流端电压的频率偏离正常工作范围,本发明实施例可以利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
请参阅图3,图3是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图。如图3所示,本实施例中所描述的逆变器反孤岛控制***,包括移相环10和驱动电路20,其中:
移相环10包括第一输入端11、第二输入端12、第三输入端13、第四输入端14、第一输出端15和第二输出端16;驱动电路20包括第一输入端21、第二输入端22、第三输入端23和输出端24。
移相环10的第一输出端15连接驱动电路20的第一输入端21,移相环10的第二输出端16连接驱动电路20的第二输入端22。
移相环10包括移相角产生电路101和移相矩阵电路102,其中:
移相角产生电路101包括第一输入端111、第二输入端121和输出端131;移相矩阵电路102包括第一输入端112、第二输入端122、第三输入端132、第一输出端142和第二输出端152。
移相角产生电路101的输出端131连接移相矩阵电路102的第三输入端132。
移相角产生电路101包括鉴频器1011、频率指令发生器1012和控制器1013,其中:
鉴频器1011包括输入端1111和输出端1211;频率指令发生器1012包括第一输入端1112、第二输出端1212和输出端1312;控制器1013包括第一输入端1113、第二输入端1213和输出端1313。
鉴频器1011的输出端1211连接频率指令发生器1012的第二输入端1212和控制器1013的第一输入端1113;频率指令发生器1012的输出端1312连接控制器1013的第二输入端1213。
鉴频器1011根据逆变器交流端电压输出逆变器交流端电压的频率作为第一频率;其中,逆变器交流端电压经鉴频器1011的输入端1111到达鉴频器1011;第一频率经鉴频器1011的输出端1211到达频率指令发生器1012的第二输入端1212和控制器1013的第一输入端1113。
频率指令发生器1012根据第一频率和并网标准中的频率保护信息确定频率指令;其中,频率保护信息经频率指令发生器1012的第一输入端1112到达频率指令发生器1012;频率指令经频率指令发生器1012的输出端1312到达控制器1013的第二输入端1213。
进一步地,上述频率保护信息包括欠频保护阈值fmin、欠频保护时间T1、过频保护阈值fmax和过频保护时间T2,而正常工作频率范围为fmin~fmax。当第一频率在正常工作频率范围内,频率指令发生器1012输出的频率指令为第一频率;当第一频率不在正常工作频率范围内,且T1<T2,频率指令发生器1012输出的频率指令为fmin;当第一频率不在正常工作频率范围内,且T1>T2,频率指令发生器1012输出的频率指令为fmax。
由此可见,当第一频率不在正常工作频率范围内,频率指令发生器将保护时间较短的频率保护阈值设定为频率指令,导致逆变器输出具有第二频率的交流电压时,第二频率向保护时间较短的频率保护阈值偏移;因此,若第二频率触发频率保护,则运行较短时间之后,逆变器便能断开与电网之间的连接,因此本实施例,可以使逆变器在发生孤岛效应时,尽快脱离孤岛状态。
作为一种可选的实施方式,上述频率保护信息包括欠频保护阈值fmin、欠频保护时间T1、过频保护阈值fmax和过频保护时间T2,而正常工作频率范围为k1fmin~k2fmax,其中,k1大于1,k2小于1,且k1fmin<k2fmax,使正常工作频率范围小于fmin~fmax的范围。举例来说,k1可为1.1,k2可为0.9。当第一频率在正常工作频率范围内,频率指令发生器1012输出的频率指令为第一频率;当第一频率不在正常工作频率范围内,且T1<T2,频率指令发生器1012输出的频率指令为fmin;当第一频率不在正常工作频率范围内,且T1>T2,频率指令发生器1012输出的频率指令为fmax。
如图4所示,图4为一种频率指令发生器确定频率指令的流程示意图。当T1<T2且f<k1fmin时,频率指令f*设置为fmin;当T1<T2且f>k1fmin时,频率指令f*设置为第一频率f;当T1>T2且f>k2fmin时,频率指令设置为fmax;当T1>T2且f<k2fmin时,频率指令设置为第一频率f。
控制器1013根据上述第一频率和上述频率指令确定移相角;上述移相角经控制器1013的输出端1313到达移相矩阵电路102的第三输入端132。控制器1013可为比例控制器、比例积分控制器、比例微分控制器等,举例来说,本发明实施例中,控制器1013为比例积
分控制器。
请参阅图5,图5为图3所描述的逆变器反孤岛***中的信号流向示意图。在图3所描述的逆变器反孤岛***中,鉴频器根据逆变器交流端电压eabc,输出逆变器交流端电压的频率作为第一频率f;频率指令发生器读取并网标准中的频率保护信息,根据频率保护信息中的欠频保护阈值fmin、欠频保护时间T1、过频保护阈值fmax和过频保护时间T2以及上述第一频率f,确定频率指令f*;控制器根据上述频率指令和上述第一频率输出移相角Δθ;孤岛移相矩阵电路根据上述移相角Δθ,改变有功电流控制单元和无功电流控制单元输出的有功电压指令和无功电压指令,输出移相后的有功电压指令和移相后的无功电压指令;驱动电路根据上述、上述和逆变器交流端电压eabc产生驱动信号,以驱动逆变器输出具有第二频率的交流电压,其中,第二频率相较于第一频率向保护时间较短的频率保护阈值偏移;若第二频率触发了欠频保护或过频保护,则逆变器按照欠频/过频保护时间运行后,断开与电网的连接,即脱离孤岛发电***。
举例来说,西班牙并网标准中,欠频保护时间为3s,孤岛保护时间为2s,欠频保护时间大于孤岛保护时间。图6a为不使用图3所公开的逆变器反孤岛控制***进行孤岛检测的波形示意图;如图6a所示,图中1~3路波形为逆变器三相输出电流的波形,第4路波形为并网开关处检测到的电流的波形;b时刻并网开关断开,并网开关处检测到的电流降为0,即发生孤岛效应;a时刻逆变器与电网断开连接,三相输出电流降为0,即脱离孤岛状态。由波形图可知,不使用图3所描述的逆变器反孤岛控制***时,逆变器发生孤岛现象后,需运行3.5秒逆变器才能脱离孤岛状态,大于并网标准中规定的孤岛保护时间,不满足并网标准对孤岛保护的要求。
而图6b为使用图3所公开的逆变器反孤岛控制***进行孤岛检测实验的波形示意图。如图6b所示,图中1~3路波形为逆变器三相输出电流的波形,第4路波形为并网开关处检测到的电流的波形;b时刻并网开关断开,并网开关处检测到的电流降为0,即发生孤岛效应;a时刻逆变器与电网断开连接,三相输出电流降为0,即脱离孤岛状态。由波形图可知,利用图3所描述的逆变器反孤岛控制***,逆变器发生孤岛现象后,仅运行0.72s便可脱离孤岛状态,小于孤岛保护时间(2s),满足西班牙并网标准中对孤岛保护的要求。
由此可见,当第一频率不在正常工作频率范围内,频率指令发生器将保护时间较短的频率保护阈值设定为频率指令,导致逆变器输出具有第二频率的交流电压时,第二频率向保护时间较短的频率保护阈值偏移;因此,若第二频率触发频率保护,则运行较短时间之后,逆变器便能断开与电网之间的连接,因此本实施例,可以使逆变器在发生孤岛效应时,尽快脱离孤岛状态。
请参阅图7,图7是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图。如图7所示,本实施例中所描述的逆变器反孤岛控制***,包括移相环10和驱动电路20,其中:
移相环10包括第一输入端11、第二输入端12、第三输入端13、第四输入端14、第一输出端15和第二输出端16;驱动电路20包括第一输入端21、第二输入端22、第三输入端23和输出端24。
移相环10的第一输出端15连接驱动电路20的第一输入端21,移相环10的第二输出
端16连接驱动电路20的第二输入端22。
移相环10包括移相角产生电路101和移相矩阵电路102,其中:
移相角产生电路101包括第一输入端111、第二输入端121和输出端131;移相矩阵电路102包括第一输入端112、第二输入端122、第三输入端132、第一输出端142和第二输出端152。
移相角产生电路101的输出端131连接移相矩阵电路102的第三输入端132。
移相角产生电路101包括鉴频器1011、频率指令发生器1012和控制器1013,其中:
鉴频器1011包括输入端1111和输出端1211;频率指令发生器1012包括第一输入端1112、第二输出端1212和输出端1312;控制器1013包括第一输入端1113、第二输入端1213和输出端1313。
鉴频器1011的输出端1211连接频率指令发生器1012的第二输入端1212和控制器1013的第一输入端1113;频率指令发生器1012的输出端1312连接控制器1013的第二输入端1213。
进一步地,上述驱动电路20包括锁相环201、旋转变换矩阵电路202和驱动信号发生器203。
锁相环201包括输入端211和输出端221;旋转变换矩阵电路202包括第一输入端212、第二输入端222、第三输入端232和输出端242;驱动信号发生器203包括输入端213和输出端223。
锁相环201的输出端221连接旋转变换矩阵电路202的第三输入端232,旋转变换矩阵电路202的输出端242连接驱动信号发生器203的输入端213。
锁相环201根据逆变器交流端电压,获得逆变器交流端电压的相位信息;其中,逆变器交流端电压经锁相环201的输入端211到达锁相环201;逆变器交流端电压的相位信息经锁相环201的输出端221到达旋转变换矩阵电路202的第三输入端232。
旋转变换矩阵电路202根据逆变器交流端电压的相位信息,将和转换为三相调制信号;其中,上述和上述经旋转变换矩阵电路202的第一输入端212和第二输入端222到达旋转变换矩阵电路202;上述三相调制信号经旋转变换矩阵电路202的输出端到达驱动信号发生器203的输入端213。
驱动信号发生器203根据上述三相调制信号产生驱动信号;驱动信号经驱动信号发生器203的输出端223到达逆变器,以驱动逆变器输出具有第二频率的交流电压,第二频率用于控制断开或保持逆变器与电网之间的连接。
当逆变器出现孤岛状态时,逆变器交流端电压的频率偏离正常工作范围,本发明实施例可以利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
请参阅图8,图8是本发明实施例公开的另一种逆变器反孤岛控制***的结构示意图。如图8所示,本实施例中所描述的逆变器反孤岛控制***,包括移相环10和驱动电路20,其中:
移相环10包括第一输入端11、第二输入端12、第三输入端13、第四输入端14、第一输出端15和第二输出端16;驱动电路20包括第一输入端21、第二输入端22、第三输
入端23和输出端24。
移相环10的第一输出端15连接驱动电路20的第一输入端21,移相环10的第二输出端16连接驱动电路20的第二输入端22。
移相环10包括移相角产生电路101和移相矩阵电路102,其中:
移相角产生电路101包括第一输入端111、第二输入端121和输出端131;移相矩阵电路102包括第一输入端112、第二输入端122、第三输入端132、第一输出端142和第二输出端152。
移相角产生电路101的输出端131连接移相矩阵电路102的第三输入端132。
移相角产生电路101包括鉴频器1011、频率指令发生器1012和控制器1013,其中:
鉴频器1011包括输入端1111和输出端1211;频率指令发生器1012包括第一输入端1112、第二输出端1212和输出端1312;控制器1013包括第一输入端1113、第二输入端1213和输出端1313。
鉴频器1011的输出端1211连接频率指令发生器1012的第二输入端1212和控制器1013的第一输入端1113;频率指令发生器1012的输出端1312连接控制器1013的第二输入端1213。
进一步地,上述驱动电路20包括锁相环201、旋转变换矩阵电路202和驱动信号发生器203。
锁相环201包括输入端211和输出端221;旋转变换矩阵电路202包括第一输入端212、第二输入端222、第三输入端232和输出端242;驱动信号发生器203包括输入端213和输出端223。
锁相环201的输出端221连接旋转变换矩阵电路202的第三输入端232,旋转变换矩阵电路202的输出端242连接驱动信号发生器203的输入端213。
除此之外,本实施例中,逆变器反孤岛控制***还包括:
最大功率点跟踪单元30、直流电压控制单元40、有功电流控制单元50、反孤岛策略单元60和无功电流控制单元70。
最大功率点跟踪单元30包括第一输入端31、第二输入端32和输出端33;直流电压控制单元40包括输入端41和输出端42;有功电流控制单元50包括输入端51和输出端52;反孤岛策略单元60包括输出端61;无功电流控制单元70包括输入端71和输出端72。
最大功率点跟踪单元30的输出端33连接直流电压控制单元40的输入端41,直流电压控制单元40的输出端42连接有功电流控制单元50的输入端51,反孤岛策略单元60的输出端61连接无功电流控制单元70的输入端71。
最大功率点跟踪单元30根据新能源发电模块输出端的直流电压和直流电流,确定新能源发电模块输出的最大功率点电压;其中,直流电压和直流电流经最大功率点跟踪单元30的第一输入端31和第二输入端32到达最大功率点跟踪单元30;最大功率点电压经最大功率点跟踪单元30的输出端33到达直流电压控制单元40的输入端41。
直流电压控制单元40根据最大功率点电压产生有功电流指令;有功电流指令经直流电压控制单元40的输出端42到达有功电流控制单元50的输入端51。
反孤岛策略单元60用于产生无功电流指令;无功电流指令经反孤岛策略单元60的输出端61到达无功电流控制单元70的输入端71。
当逆变器出现孤岛状态时,逆变器交流端电压的频率偏离正常工作范围,本发明实施例可以利用移相环使逆变器交流端电压的频率偏移至第二频率,使其触发频率保护从而断开与电网之间的连接,即脱离孤岛状态。
以上对本发明实施例所提供的一种逆变器反孤岛控制***进行了详细介绍,本文中应用了具体个例对本发明的原理及实施方式进行了阐述,以上实施例的说明只是用于帮助理解本发明的方法及其核心思想,但本发明的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本发明实施例揭露的技术范围内,可轻易想到的变化或替换,都应涵盖在本发明的保护范围之内。因此,本发明的保护范围应该以权利要求的保护范围为准。
Claims (10)
- 一种逆变器反孤岛控制***,其特征在于,包括:移相环和驱动电路;所述移相环包括第一输入端、第二输入端、第三输入端、第四输入端、第一输出端和第二输出端;所述驱动电路包括第一输入端、第二输入端、第三输入端和输出端;所述移相环的第一输出端连接所述驱动电路的第一输入端,所述移相环的第二输出端连接所述驱动电路的第二输入端;所述移相环用于根据所述逆变器交流端电压和并网标准中的频率保护信息,将有功电压指令和无功电压指令进行移相变换,得到移相后的有功电压指令和移相后的无功电压指令其中,所述所述所述逆变器交流端电压和所述并网标准中的频率保护信息分别经所述移相环的第一输入端、第二输入端、第三输入端和第四输入端到达所述移相环;所述经所述移相环的第一输出端到达所述驱动电路的第一输入端,所述经所述移相环的第二输出端到达所述驱动电路的第二输入端;
- 根据权利要求1所述的***,其特征在于,所述移相环包括移相角产生电路和移相矩阵电路,其中:所述移相角产生电路包括第一输入端、第二输入端和输出端;所述移相矩阵电路包括第一输入端、第二输入端、第三输入端、第一输出端和第二输出端;所述移相角产生电路的输出端连接所述移相矩阵电路的第三输入端;所述移相角产生电路用于根据所述逆变器交流端电压和所述频率保护信息产生移相角;其中,所述逆变器交流端电压和所述频率保护信息分别经所述移相角产生电路的第一输入端和第二输入端到达所述移相角产生电路;所述移相角经所述移相角产生电路的输出端到达所述移相矩阵电路的第三输入端;
- 根据权利要求2所述的***,其特征在于,所述移相角产生电路包括鉴频器、频率指令发生器和控制器,其中:所述鉴频器包括输入端和输出端;所述频率指令发生器包括第一输入端、第二输出端和输出端;所述控制器包括第一输入端、第二输入端和输出端;所述鉴频器的输出端连接所述频率指令发生器的第二输入端和所述控制器的第一输入端;所述频率指令发生器的输出端连接所述控制器的第二输入端;所述鉴频器用于根据所述逆变器交流端电压输出所述逆变器交流端电压的频率作为第 一频率;其中,所述逆变器交流端电压经所述鉴频器的输入端到达所述鉴频器;所述第一频率经所述鉴频器的输出端到达所述频率指令发生器的第二输入端和所述控制器的第一输入端;所述频率指令发生器用于根据所述第一频率和所述频率保护信息确定频率指令;其中,所述频率保护信息经所述频率指令发生器的第一输入端到达所述频率指令发生器;所述频率指令经所述频率指令发生器的输出端到达所述控制器的第二输入端;所述控制器用于根据所述第一频率和所述频率指令确定所述移相角;所述移相角经所述控制器的输出端到达所述移相矩阵电路的第三输入端。
- 根据权利要求3所述的***,其特征在于,所述频率保护信息包括欠频保护阈值fmin、欠频保护时间T1、过频保护阈值fmax和过频保护时间T2;正常工作频率范围为fmin~fmax;所述频率指令发生器用于根据所述第一频率和所述频率保护信息确定频率指令,包括:当所述第一频率在所述正常工作频率范围内,所述频率指令发生器用于输出的所述频率指令为所述第一频率;当所述第一频率不在所述正常工作频率范围内,且T1<T2,所述频率指令发生器用于输出的所述频率指令为所述fmin;当所述第一频率不在所述正常工作频率范围内,且T1>T2,所述频率指令发生器用于输出的所述频率指令为所述fmax。
- 根据权利要求1~4中任意一项所述的***,其特征在于,所述驱动电路包括:锁相环、旋转变换矩阵电路和驱动信号发生器;所述锁相环包括输入端和输出端;所述旋转变换矩阵电路包括第一输入端、第二输入端、第三输入端和输出端;所述驱动信号发生器包括输入端和输出端;所述锁相环的输出端连接所述旋转变换矩阵电路的第三输入端,所述旋转变换矩阵电路的输出端连接所述驱动信号发生器的输入端;所述锁相环用于根据所述逆变器交流端电压,获得所述逆变器交流端电压的相位信息;其中,所述逆变器交流端电压经所述锁相环的输入端到达所述锁相环;所述逆变器交流端电压的相位信息经所述锁相环的输出端到达所述旋转变换矩阵电路的第三输入端;所述旋转变换矩阵电路用于根据所述逆变器交流端电压的相位信息,将所述和所述转换为三相调制信号;其中,所述和所述经所述旋转变换矩阵电路的第一输入端和第二输入端到达所述旋转变换矩阵电路;所述三相调制信号经所述旋转变换矩阵电路的输出端到达所述驱动信号发生器的输入端;所述驱动信号发生器用于根据所述三相调制信号产生所述驱动信号;所述驱动信号经所述驱动信号发生器的输出端到达所述逆变器,以驱动所述逆变器输出具有所述第二频率的交流电压,所述第二频率用于控制断开或保持所述逆变器与电网之间的连接。
- 根据权利要求5所述的***,其特征在于,所述***还包括:最大功率点跟踪单元、直流电压控制单元、有功电流控制单元、反孤岛策略单元和无功电流控制单元;所述最大功率点跟踪单元包括第一输入端、第二输入端和输出端;所述直流电压控制单元包括输入端和输出端;所述有功电流控制单元包括输入端和输出端;所述反孤岛策略 单元包括输出端;所述无功电流控制单元包括输入端和输出端;所述最大功率点跟踪单元的输出端连接所述直流电压控制单元的输入端,所述直流电压控制单元的输出端连接所述有功电流控制单元的输入端,所述反孤岛策略单元的输出端连接所述无功电流控制单元的输入端;所述最大功率点跟踪单元用于根据新能源发电模块输出端的直流电压和直流电流,确定新能源发电模块输出的最大功率点电压;其中,所述直流电压和所述直流电流经所述最大功率点跟踪单元的第一输入端和第二输入端到达所述最大功率点跟踪单元;所述最大功率点电压经所述最大功率点跟踪单元的输出端到达所述直流电压控制单元的输入端;所述直流电压控制单元用于根据所述最大功率点电压产生有功电流指令;所述有功电流指令经所述直流电压控制单元的输出端到达所述有功电流控制单元的输入端;所述反孤岛策略单元用于产生无功电流指令;所述无功电流指令经所述反孤岛策略单元的输出端到达所述无功电流控制单元的输入端;
- 根据权利要求1~8中任意一项所述的***,其特征在于,所述逆变器为单向逆变器、三项逆变器、两电平拓扑逆变器或多电平拓扑逆变器中的任意一种。
- 根据权利要求3~9中任意一项所述的***,其特征在于,所述控制器为比例控制器、比例积分控制器、比例微分控制器中的任意一种。
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