CN219225042U - Power grid simulation device capable of independently and controllably outputting voltages of all phases - Google Patents
Power grid simulation device capable of independently and controllably outputting voltages of all phases Download PDFInfo
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Abstract
The utility model discloses a power grid simulation device capable of independently controlling the voltage of each phase, which comprises a three-phase multi-winding transformer, a power module array, an inverter and an output filter, wherein the input end of the three-phase multi-winding transformer is connected with a three-phase power grid; the inverter is provided with a three-phase output end and a midpoint output end; the power module array comprises three groups of power modules which respectively correspond to one-phase output, each group of power modules at least comprises 2 power modules, each power module comprises a rectifier, a direct current bus link and a single-phase H-bridge inverter which are sequentially connected, the alternating current input end of each rectifier is correspondingly connected with one secondary winding of the three-phase multi-winding transformer, and the direct current bus link comprises a direct current capacitor group; the power grid simulation device adopts the inverter with the midpoint output end and the three-phase power module array and is provided with the three-phase output filter with the midpoint, so that not only can the independent control of the three-phase voltage output by the device be realized, but also the independent control of the high-frequency disturbance voltage can be realized.
Description
Technical Field
The utility model relates to the technical field of new energy equipment testing, in particular to a power grid simulation device capable of independently and controllably outputting voltages of all phases.
Background
With the continuous improvement of the duty ratio of the new energy power generation in the power system, the power industry puts forward higher requirements on the power grid adaptability and the fault voltage ride through capability of the new energy power generation equipment in order to meet the requirements of safe and stable operation of the power system. Under the background, a matched power grid adaptability test technology and a fault voltage ride-through test technology must be developed to realize voltage drop, rise or other disturbance characteristic simulation of the power grid voltage in the forms of three-phase symmetry, single-phase asymmetry, two-phase asymmetry and the like, so that comprehensive power grid adaptability and fault voltage ride-through test are performed on the new energy power generation equipment.
Patent application number 201510357695.3 discloses a three-phase power grid disturbance generating device composed of a three-phase multi-winding transformer, a power module array and an output filter, wherein the device can output various power grid disturbance characteristics such as voltage deviation, frequency deviation, flicker, voltage unbalance and the like.
But the device is a three-phase three-wire system, so that direct simulation of voltage drop or rise of a single-phase asymmetric or two-phase asymmetric form of the power grid voltage cannot be realized, the device is not suitable for testing single-phase and two-phase voltage fault ride-through characteristics of a photovoltaic power station and an energy storage system, and independent control of high-frequency disturbance voltage cannot be realized.
Disclosure of Invention
The utility model aims to solve the technical problem of providing a power grid simulation device with independently controllable output voltages of various phases, which can realize the simulation of asymmetric characteristics including single-phase or two-phase falling or rising of the power grid voltage, so that the device can be used for testing the adaptability of the power grid including single-phase and two-phase grounding short-circuit fault ride-through characteristics and single-phase and two-phase voltage rising fault ride-through characteristics of a photovoltaic power station and an energy storage system or other asymmetric characteristics.
In order to solve the technical problems, the power grid simulation device capable of independently controlling the voltages of all phases comprises a three-phase multi-winding transformer, a power module array, an inverter and an output filter,
the input end of the three-phase multi-winding transformer is connected with a three-phase power grid;
the inverter is provided with a three-phase output end and a midpoint output end;
the power module array comprises three groups of power modules, each group of power modules corresponds to one-phase output, each group of power modules at least comprises two power modules, each power module comprises a rectifier, a direct current bus link and a single-phase H-bridge inverter which are sequentially connected, the alternating current input end of each rectifier is correspondingly connected with one secondary winding of the three-phase multi-winding transformer, and the direct current bus link comprises a direct current capacitor group; the output ends of the single-phase H-bridge inverters of the power modules in each group are cascaded and form two output ends, wherein one output end is correspondingly connected with one phase output end of the inverter, and the other output end is correspondingly connected with one phase input end of the output filter; the midpoint output end of the inverter is connected with the midpoint input end of the output filter;
and the three-phase output end and the midpoint output end of the output filter are connected with a test bus.
Preferably, the rectifier and the single-phase H-bridge inverter of each power module adopt a two-level structure or a three-level structure.
Preferably, the inverter comprises three bridge arms and a series capacitor bank; each bridge arm adopts a two-level structure or a three-level structure, and the alternating current output ends of the bridge arms are respectively used as one-phase output ends of the inverter; the midpoint of the series capacitor bank is used as a midpoint output end of the inverter.
Preferably, the inverter includes four bridge arms, each bridge arm adopts a two-level structure or a three-level structure, wherein the ac output ends of three bridge arms are respectively used as three-phase output ends of the inverter, and the ac output end of one bridge arm is used as a midpoint output end of the inverter.
Preferably, the power grid simulation device with independently controllable output voltages of each phase further comprises a controller in communication connection with the power module and the inverter.
Preferably, the output filter includes an output transformer and a three-phase capacitor;
the three-phase input ends of primary side three-phase windings of the output transformer are connected with the three-phase output ends of the power module array in a one-to-one correspondence manner, and the middle point of the primary side three-phase windings of the output transformer is connected with the middle point output end of the inverter;
the three-phase output ends of the secondary side three-phase windings of the output transformer are connected with the three phase lines of the three-phase capacitor in a one-to-one correspondence mode and form a three-phase output end of the output filter, and the midpoint of the secondary side three-phase windings of the output transformer is connected with the midpoint of the three-phase capacitor and forms a midpoint output end of the output filter.
Preferably, the output filter includes a three-phase reactor, a three-phase capacitor, and an output transformer;
the three-phase input ends of the three-phase reactors are connected with the three-phase output ends of the power module array in a one-to-one correspondence manner, and the three-phase output ends of the three-phase reactors are connected with the three-phase input ends of the primary side three-phase windings of the output transformer and the three phase lines of the three-phase capacitor in a one-to-one correspondence manner;
the midpoint of the primary side three-phase winding of the output transformer is connected with the midpoint of the three-phase capacitor and the midpoint output end of the inverter; the three-phase output ends of the secondary side three-phase windings of the output transformer form a three-phase output end of the output filter, and the middle point of the three-phase output ends of the output filter.
Preferably, the three-phase capacitor, the primary side three-phase winding of the output transformer and the secondary side three-phase winding of the output transformer are all in star connection.
Preferably, the output transformer comprises one of a four-core column structure output transformer, a five-core column structure output transformer and an output transformer composed of three single-phase transformers.
After the structure is adopted, the power grid simulation device realizes independent control of the three-phase voltage output by the device by adopting the inverter with the midpoint output end, the three-phase power module array and the three-phase output filter with the midpoint, and further realizes simulation of asymmetric characteristics including falling or rising of single-phase or two-phase of power grid voltage, so that the device can be used for testing photovoltaic power stations, energy storage systems and other power grid adaptability tests such as single-phase or two-phase grounding short circuit fault ride-through characteristics and single-phase or two-phase voltage rising fault ride-through characteristics, and can realize independent control of high-frequency disturbance voltage.
Drawings
FIG. 1 is a circuit diagram of a power grid simulation device with independently controllable output voltages of each phase;
FIG. 2 is a second overall circuit diagram of the power grid simulation device with independently controllable output voltages of each phase;
FIG. 3 is a third overall circuit diagram of the power grid simulation device with independently controllable output voltages of each phase;
FIG. 4 is a circuit diagram of a power module of the power grid simulation device with independently controllable output voltages of each phase;
FIG. 5 is a second power module circuit diagram of the power grid simulation device with independently controllable output voltages of each phase;
FIG. 6 is a schematic diagram of an inverter circuit of the grid simulator of the present utility model with independently controllable output voltages of each phase;
fig. 7 is a second inverter circuit diagram of the power grid simulation device with independently controllable output voltages of each phase.
The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved by the application clearer and more obvious, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
In the description of the present application, it should be understood that the directions or positional relationships indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of description of the present application and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Example 1
Referring to fig. 1, the present embodiment discloses a power grid simulation device with independently controllable output voltages of each phase, which includes a three-phase multi-winding transformer 10, a power module array 20, an inverter 30 and an output filter 40, wherein an input end of the three-phase multi-winding transformer 10 is connected with a three-phase power grid;
the inverter 30 has a three-phase output and a midpoint output;
the power module array 20 includes three groups of power modules, each group of power modules corresponds to one-phase output, each group of power modules includes at least two power modules, each power module includes a rectifier, a dc bus link and a single-phase H-bridge inverter which are sequentially connected, an ac input end of each rectifier is correspondingly connected with a secondary winding of the three-phase multi-winding transformer, and the dc bus link includes a dc capacitor group; the output ends of the single-phase H-bridge inverters of the A-phase power modules are cascaded and form two output ends A, X, the output ends of the single-phase H-bridge inverters of the B-phase power modules are cascaded and form two output ends B, Y, and the output ends of the single-phase H-bridge inverters of the C-phase power modules are cascaded and form two output ends C, Z;
the output filter 40 has an ABC three-phase input, a midpoint input, an ABC three-phase output, and a midpoint output N;
three phase output ends of the inverter 30 are respectively and correspondingly connected with three output ends XYZ of the power module array 20;
the three-phase ABC input ends of the output filter 40 are connected with the three output ends ABC of the power module array 20 in a one-to-one correspondence manner, that is, the phase a input end of the output filter 40 is connected with the phase a output end of the power module array 20, the phase B input end of the output filter 40 is connected with the phase B output end of the power module array 20, and the phase C input end of the output filter 40 is connected with the phase C output end of the power module array 20;
the midpoint output end of the inverter 30 is connected with the midpoint input end of the output filter 40; the ABC three-phase output terminal and the midpoint output terminal N of the output filter 40 are connected to a test bus.
Example two
Referring to fig. 2 or 3, the present embodiment is based on the first embodiment, in the present embodiment, the three-phase multi-winding transformer 10 includes a primary side three-phase winding and 3n secondary side three-phase windings (secondary side windings A1 to An, secondary side windings B1 to Bn, and secondary side windings C1 to Cn), an input end of the primary side three-phase winding is connected to a three-phase power grid, the primary side three-phase winding of the three-phase multi-winding transformer 10 is in star connection or delta connection, and the secondary side three-phase winding of the three-phase multi-winding transformer 10 is in star connection or delta connection. In fig. 2, primary side three-phase windings of the three-phase multi-winding transformer 10 are in star connection, and secondary side three-phase windings of the three-phase multi-winding transformer 10 are in delta connection; in fig. 3, primary three-phase windings of the three-phase multi-winding transformer 10 are connected in a delta shape, and secondary three-phase windings of the three-phase multi-winding transformer 10 are connected in a star shape.
In this embodiment, the power module array 20 includes a group a power module, a group B power module, and a group C power module; the group A power module, the group B power module and the group C power module all comprise n power modules.
Each power module comprises a rectifier, a direct current bus link and a single-phase H-bridge inverter which are sequentially connected, wherein the alternating current input end of each rectifier is correspondingly connected with one secondary winding of the three-phase multi-winding transformer, and the direct current bus link comprises a direct current capacitor group; the output ends of the single-phase H-bridge inverters of each group of power modules are connected in series to form a first output end and a second output end which are connected in series. The group A power modules comprise n power modules, the input ends of n rectifiers are connected with n secondary windings A1-An in one-to-one correspondence, and the output ends of n single-phase H-bridge inverters are connected in series to form a first output end X and a second output end A which are connected in series. Group B power modules and group C power modules are similar.
The first output end X, B of the group a power modules and the first output end Y of the group C power modules are respectively and correspondingly connected to the three-phase output end of the inverter 30; the second output ends A, B of the a-group power modules and the second output ends B, C of the a-group power modules are respectively and correspondingly connected with the ABC three-phase input ends of the output filter 40.
Referring to fig. 4, in this embodiment, each power module includes a three-phase rectifier, a dc bus link, and a single-phase H-bridge inverter connected in sequence; the three-phase rectifier and the single-phase H-bridge inverter both adopt a two-level structure. The three-phase rectifier comprises three bridge arms, and the single-phase H-bridge inverter comprises two bridge arms which are formed by two switching tubes connected in series; the switching tube comprises an IGBT or an IGCT or other power semiconductor devices; the direct current bus link comprises one or more capacitors or capacitor groups connected between the positive bus and the negative bus.
Referring to fig. 5, in this embodiment, each power module includes a three-phase rectifier, a dc bus link, and a single-phase H-bridge inverter that are sequentially connected; the three-phase rectifier and the single-phase H-bridge inverter both adopt three-level structures. Specifically, the three-phase rectifier comprises three bridge arms, the single-phase H-bridge inverter comprises two bridge arms, and the bridge arms are formed by four switching tubes connected in series; the switching tube comprises an IGBT or an IGCT or other power semiconductor device, and the direct current bus link comprises one or more capacitors or capacitor groups connected between the positive bus and the negative bus of the switching tube.
Example III
Referring to fig. 6, in this embodiment, the inverter includes three bridge arms and a series capacitor set, each bridge arm adopts a two-level structure or a three-level structure, and is formed by a plurality of switching tubes, the switching tubes include IGBTs or IGCTs or other power semiconductor devices, and ac output ends of each bridge arm are respectively used as a phase output end of the inverter; the midpoint of the series capacitor bank is used as a midpoint output end of the inverter. After the mode is adopted, the inverter can generate power frequency voltage and high frequency voltage; the power grid simulation device can not only control the device to integrally output independently controllable phase voltage relative to the midpoint output end through the inverter, but also output independently controllable high-frequency disturbance voltage according to the requirement.
Example IV
Referring to fig. 7, in this embodiment, the inverter includes four bridge arms, each of the bridge arms adopts a two-level structure or a three-level structure, and is formed by a plurality of switching tubes, the switching tubes include IGBTs or IGCTs or other power semiconductor devices, wherein ac output ends of three bridge arms are respectively used as three-phase output ends of the inverter, and ac output ends of another bridge arm are used as midpoint output ends of the inverter, and after the above manner is adopted, the inverter can not only generate power frequency voltage, but also generate high frequency voltage; the power grid simulation device can not only control the device to integrally output independently controllable phase voltage relative to the midpoint output end through the inverter, but also output independently controllable high-frequency disturbance voltage according to the requirement.
Example five
Referring to fig. 2, in the present embodiment, the output filter 40 includes an output transformer and a three-phase capacitor;
the ABC three-phase input end of the primary side three-phase winding of the output transformer is connected with the ABC three-phase output end of the power module array in a one-to-one correspondence manner, and the midpoint of the primary side three-phase winding of the output transformer is connected with the midpoint output end of the inverter;
the ABC three-phase output end of the secondary side three-phase winding of the output transformer is connected with the ABC three-phase lines of the three-phase capacitor in a one-to-one correspondence manner and forms an ABC three-phase output end of the output filter 40, and the midpoint of the secondary side three-phase winding of the output transformer is connected with the midpoint of the three-phase capacitor and forms a midpoint output end N of the output filter 40.
In this embodiment, the three-phase capacitor, the primary side three-phase winding of the output transformer, and the secondary side three-phase winding of the output transformer are all star-connected. The output transformer comprises one of an output transformer with a four-core column structure, an output transformer with a five-core column structure and an output transformer composed of three single-phase transformers.
Example six
Referring to fig. 3, in the present embodiment, the output filter 40 includes a three-phase reactor, a three-phase capacitor, and an output transformer; the ABC three-phase input end of the three-phase reactor is connected with the ABC three-phase output end of the power module array 20 in a one-to-one correspondence manner, and the ABC three-phase output end of the three-phase reactor is connected with the three-phase input end of the primary side three-phase winding of the output transformer and the ABC three phase lines of the three-phase capacitor in a one-to-one correspondence manner;
the midpoint of the primary side three-phase winding of the output transformer is connected with the midpoint of the three-phase capacitor and the midpoint output end of the inverter; the ABC three-phase output of the secondary three-phase winding of the output transformer forms the ABC three-phase output of the output filter 40, and its midpoint forms the midpoint output N of the output filter 40.
In this embodiment, the three-phase capacitor, the primary side three-phase winding of the output transformer, and the secondary side three-phase winding of the output transformer are all star-connected. The output transformer comprises one of an output transformer with a four-core column structure, an output transformer with a five-core column structure and an output transformer composed of three single-phase transformers.
Example seven
Referring to fig. 1, the power grid simulation device capable of independently controlling the voltages of the respective phases further includes a controller communicatively connected to the power module and the inverter. The controller is connected with each power module and the inverter through optical fiber communication and performs unified and coordinated control, so that the anti-interference performance and the operation reliability of the system can be improved.
The preferred embodiments of the present application have been described above with reference to the accompanying drawings, and are not thereby limiting the scope of the claims of the present application. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and spirit of the present application shall fall within the scope of the claims of the present application.
Claims (9)
1. An independently controllable power grid simulation device for outputting voltages of all phases comprises a three-phase multi-winding transformer, a power module array, an inverter and an output filter, and is characterized in that,
the input end of the three-phase multi-winding transformer is connected with a three-phase power grid;
the inverter is provided with a three-phase output end and a midpoint output end;
the power module array comprises three groups of power modules, each group of power modules corresponds to one-phase output, each group of power modules at least comprises two power modules, each power module comprises a rectifier, a direct current bus link and a single-phase H-bridge inverter which are sequentially connected, the alternating current input end of each rectifier is correspondingly connected with one secondary winding of the three-phase multi-winding transformer, and the direct current bus link comprises a direct current capacitor group; the output ends of the single-phase H-bridge inverters of the power modules in each group are cascaded and form two output ends, wherein one output end is correspondingly connected with one phase output end of the inverter, and the other output end is correspondingly connected with one phase input end of the output filter; the midpoint output end of the inverter is connected with the midpoint input end of the output filter;
and the three-phase output end and the midpoint output end of the output filter are connected with a test bus.
2. The power grid simulator of claim 1, wherein the output voltages of the phases are independently controllable,
and the rectifier and the single-phase H-bridge inverter of each power module adopt a two-level structure or a three-level structure.
3. The power grid simulator of claim 2 wherein the inverter comprises three legs and a series capacitor bank; each bridge arm adopts a two-level structure or a three-level structure, and the alternating current output ends of the bridge arms are respectively used as one-phase output ends of the inverter; the midpoint of the series capacitor bank is used as a midpoint output end of the inverter.
4. The power grid simulation device capable of independently controlling voltage of each phase according to claim 3, wherein the inverter comprises four bridge arms, each bridge arm adopts a two-level structure or a three-level structure, alternating current output ends of three bridge arms are respectively used as three-phase output ends of the inverter, and alternating current output ends of one bridge arm are used as midpoint output ends of the inverter.
5. The independently controllable power grid simulator of claim 1, wherein the independently controllable power grid simulator further comprises a controller in communication with the power module and the inverter.
6. The power grid simulator of claim 1 wherein the output filter comprises an output transformer and a three-phase capacitor;
the three-phase input ends of primary side three-phase windings of the output transformer are connected with the three-phase output ends of the power module array in a one-to-one correspondence manner, and the middle point of the primary side three-phase windings of the output transformer is connected with the middle point output end of the inverter;
the three-phase output ends of the secondary side three-phase windings of the output transformer are connected with the three phase lines of the three-phase capacitor in a one-to-one correspondence mode and form a three-phase output end of the output filter, and the middle point of the secondary side three-phase windings of the output transformer is connected with the middle point of the three-phase capacitor and forms a middle point output end of the output filter.
7. The power grid simulator of claim 1 wherein the output filter comprises a three-phase reactor, a three-phase capacitor and an output transformer;
the three-phase input ends of the three-phase reactors are connected with the three-phase output ends of the power module array in a one-to-one correspondence manner, and the three-phase output ends of the three-phase reactors are connected with the three-phase input ends of the primary side three-phase windings of the output transformer and the three phase lines of the three-phase capacitor in a one-to-one correspondence manner;
the midpoint of the primary side three-phase winding of the output transformer is connected with the midpoint of the three-phase capacitor and the midpoint output end of the inverter; the three-phase output ends of the secondary side three-phase windings of the output transformer form a three-phase output end of the output filter, and the middle point of the three-phase output ends of the output filter.
8. The independently controllable power grid simulation device for outputting voltages of each phase according to claim 6 or 7, wherein the three-phase capacitor, the primary side three-phase winding of the output transformer and the secondary side three-phase winding of the output transformer are all in star connection.
9. The independently controllable power grid simulation device for outputting voltages of each phase according to claim 6 or 7, wherein the output transformer comprises one of a four-core structure output transformer, a five-core structure output transformer and an output transformer composed of three single-phase transformers.
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