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CN118381341A - A power frequency isolation type multi-level energy router - Google Patents

A power frequency isolation type multi-level energy router Download PDF

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Publication number
CN118381341A
CN118381341A CN202410534125.6A CN202410534125A CN118381341A CN 118381341 A CN118381341 A CN 118381341A CN 202410534125 A CN202410534125 A CN 202410534125A CN 118381341 A CN118381341 A CN 118381341A
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CN
China
Prior art keywords
switch tube
power switch
phase
bus terminal
module
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202410534125.6A
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Chinese (zh)
Inventor
李锦�
闵陆廷
沈卓栋
唐维溢
钱黎俊
闫业看
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Shanghai University of Electric Power
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Shanghai University of Electric Power
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Application filed by Shanghai University of Electric Power filed Critical Shanghai University of Electric Power
Priority to CN202410534125.6A priority Critical patent/CN118381341A/en
Publication of CN118381341A publication Critical patent/CN118381341A/en
Pending legal-status Critical Current

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Classifications

    • 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
    • H02M5/00—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC
    • H02M5/04—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters
    • H02M5/10—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters using transformers
    • 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
    • H02M1/12—Arrangements for reducing harmonics from AC input or output
    • 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
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of AC power input into DC 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
    • H02M7/217—Conversion of AC power input into DC 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
    • H02M7/2173—Conversion of AC power input into DC 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 in a biphase or polyphase circuit arrangement

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention relates to a power frequency isolation type multi-level energy router which comprises a three-phase winding power frequency isolation transformer, two three-phase five-level AC/DC converter modules and filters corresponding to each converter module, wherein the power frequency isolation transformer is provided with a primary winding and a secondary winding, the primary winding of the power frequency isolation transformer is connected with a power grid by adopting a triangle connection method, and the secondary winding of the power frequency isolation transformer is two independent three-phase windings. Compared with the prior art, the invention has the advantages of multiple output voltage levels, low harmonic content, simple system structure and the like.

Description

Power frequency isolation type multi-level energy router
Technical Field
The invention relates to the field of power electronics, in particular to a power frequency isolation type multi-level energy router.
Background
AC/DC converters can be classified into non-isolated and isolated types depending on whether they are electrically isolated by a transformer. The non-isolated current transformer has a relatively simple structure, mature research technology and easier control realization. In order to improve the safety and reliability of the AC/DC converter, electrical isolation is required to be added between the network side and the load side, and the isolation type AC/DC converter is formed by introducing a transformer, so that the requirements of voltage rise and fall conversion are met while isolation is realized, the working performance of the converter is greatly improved, and the safety of a system is also remarkably improved.
In the structure of the existing energy router, an H-bridge cascade multi-level converter is mostly adopted so as to be suitable for high-voltage and high-power occasions. The cascade single-phase structure enables each phase circuit to have a fundamental frequency doubling component of the power grid voltage in the instantaneous power exchange process, so that low-frequency fluctuation of capacitor voltage at a direct current side is caused, and a double frequency filter is required to be additionally arranged to ensure the quality of the direct current voltage. In the existing research, the output side of the isolation stage DC/DC module is connected with each port of the output stage in parallel, and an energy router needs to be additionally provided with an additional DC/DC converter to meet the access requirements of the AC/DC power grids with different voltage levels, so that the complexity of the system is improved.
Disclosure of Invention
The invention aims to provide a power frequency isolation type multi-level energy router for realizing multi-level output and simplifying a system structure, and the power frequency isolation type multi-level energy router does not need to adopt an additional DC/DC converter, is beneficial to realizing the miniaturization and the light weight of equipment, and simultaneously realizes multiple output voltage levels.
The aim of the invention can be achieved by the following technical scheme:
the power frequency isolation type multi-level energy router comprises a three-phase winding power frequency isolation transformer, two three-phase five-level AC/DC converter modules and filters corresponding to each converter module, wherein the power frequency isolation transformer is provided with a primary winding and a secondary winding, the primary winding of the power frequency isolation transformer is connected with a power grid by adopting a triangle connection method, the secondary winding of the power frequency isolation transformer is two independent three-phase windings, namely a first three-phase winding and a second three-phase winding, the two three-phase windings are respectively connected with the two three-phase five-level AC/DC converter modules, and the first three-phase winding consists of a 1、b1、c1 three phases; the second three-phase winding consists of a 2、b2、c2; each two phases of the first three-phase winding are mutually independent; each two phases of the second three-phase winding are mutually independent.
The two three-phase five-level AC/DC converter modules are a first three-phase five-level AC/DC converter module and a second three-phase five-level AC/DC converter module respectively;
The first three-phase five-level AC/DC converter module consists of three single-phase five-level AC/DC converter modules, namely a first module, a second module and a third module, wherein the first module, the second module and the third module are correspondingly connected with the a 1、b1、c1 three-phase winding respectively; the second three-phase five-level AC/DC converter module consists of three single-phase five-level AC/DC converter modules, namely a fourth module, a fifth module and a sixth module, wherein the fourth module, the fifth module and the sixth module are correspondingly connected with the a 2、b2、c2 three-phase winding respectively;
The single-phase five-level AC/DC converter module is provided with three direct current buses, namely a positive bus end V up+, a negative bus end NP 1 and a negative bus end;
The positive, negative and zero direct current buses of the fourth, fifth and sixth modules are correspondingly connected to form three output ports of the second three-phase five-level AC/DC converter module, namely a positive bus end V down+, a zero bus end NP 2 and a negative bus end V down-;
The filter corresponding to the first three-phase five-level AC/DC converter module is a first filter, the filter corresponding to the second three-phase five-level AC/DC converter module is a second filter, the three-phase five-level AC/DC converter module is of an eight-power switch tube topological structure, wherein a positive bus end V up+ is connected with a positive bus end V down+, a negative bus end V down- is connected with a negative bus end V up-, a zero bus end NP 1 is connected with a zero bus end NP 2, two three-phase windings are connected in parallel, at the moment, the positive bus end V up+ and the positive bus end V up+ are positive direct current buses, the negative bus end V down- and the negative bus end V up- are negative direct current buses, the zero bus end NP 1 and the zero bus end NP 2 are zero direct current buses, and the energy router outputs 2Vdc or Vdc and Vdc represent bus voltages;
Or the negative bus end V up- is connected with the positive bus end V down+, at the moment, two three-phase windings are connected in series, the positive bus end V up+ is an upper positive bus, the zero bus end NP 1 is an upper zero bus, the negative bus end V up- and the positive bus end V down+ are an upper negative bus-a lower positive bus, the negative bus end V down- is a lower negative bus, the zero bus end NP 2 is a lower zero bus, and the energy router outputs 4Vdc or 3Vdc or 2Vdc or Vdc;
Or the positive bus terminal V down+, the zero bus terminal NP 2 and the negative bus terminal V down-, and the positive bus terminal V up+, the zero bus terminal NP 1 and the negative bus terminal V up- are all independently disconnected, and the energy router outputs 2Vdc or Vdc.
Further, each phase of the three-phase five-level AC/DC converter module is of an eight-power switching tube topological structure, the eight-power switching tube topological structure comprises eight switches and two output direct-current side capacitors, and the eight-power switching tube topological structure is divided into a first branch, a second branch, a third branch and a fourth branch.
Further, the eight switches are a first power switch tube S 1, a second power switch tube S 2, a three power switch tube S 3, a fourth power switch tube S 4, a fifth power switch tube S 5, a sixth power switch tube S 6, a seventh power switch tube S 7 and an eighth power switch tube S 8, respectively; ;
The first branch circuit comprises a first power switch tube S 1 and a second power switch tube S 2 which are connected in series, and the drain electrode of the second power switch tube S 2 is connected with the source electrode of the first power switch tube S 1;
The second branch is connected with the first branch in parallel, the second branch is formed by connecting a third power switch tube S 3 and a fourth power switch tube S 4 in series, and the drain electrode of the fourth power switch tube S 4 is connected with the source electrode of the third power switch tube S 3;
The third branch is connected with the first branch in parallel, the third branch is formed by connecting a fifth power switch tube S 5 and a sixth power switch tube S 6 in series, and the drain electrode of the sixth power switch tube S 6 is connected with the source electrode of the fifth power switch tube S 5;
The seventh power switching tube S 7 and the eighth power switching tube S 8 are connected in series with the first branch, the second branch and the third branch;
The fourth branch consists of two capacitors C dc with equal size, and the midpoint of the fourth branch is connected with the midpoint of the third branch.
Further, the drain electrode of the eighth power switch tube S 8 is connected to the source electrodes of the second power switch tube S 2, the fourth power switch tube S 4 and the sixth power switch tube S 6, and the source electrode of the seventh power switch tube S 7 is connected to the drain electrodes of the first power switch tube S 1, the third power switch tube S 3 and the fifth power switch tube S 5.
Further, the drain electrode of the seventh power switch tube S 7 is connected with a positive bus end, the source electrode of the eighth power switch tube S 8 is connected with a negative bus end, and the connection part of the two equal capacitance quality tests is a zero bus end.
Further, the corresponding filter of the three-phase five-level AC/DC converter module is a single-inductor L filter or an LCL filter, and the LCL filter is composed of an inductor L c, an inductor L f and a capacitor C d.
Further, one end of the inductor L c is connected to the midpoint of the second branch, the other end of the inductor L c is connected to one end of the inductor L f and one end of the capacitor C d, and the other end of the inductor L f is connected to the positive electrode V in+,Cd of the input ac voltage, the other end of the inductor L3524 is connected to the midpoint of the first branch, and the other end of the inductor L c is connected to the negative electrode V in- of the ac voltage.
Further, the power switch transistor is an insulated gate bipolar transistor with an anti-parallel diode.
Further, the first power switching tube S 1, the second power switching tube S 2, the third power switching tube S 3 and the fourth power switching tube S 4 are switched at a lower switching frequency in the power frequency, and the fifth power switching tube S 5, the sixth power switching tube S 6, the seventh power switching tube S 7 and the eighth power switching tube S 8 are switched at a higher switching frequency in the power frequency.
Further, in the same phase of the three-phase five-level AC/DC converter module, the voltage between the positive bus terminal and the zero bus terminal is Vdc, the voltage between the negative bus terminal and the zero bus terminal is-Vdc, and the voltage between the positive bus terminal and the negative bus terminal is 2Vdc.
Compared with the prior art, the invention has the following beneficial effects:
The two three-phase windings of the secondary side of the isolated energy router can work in three working modes of series connection, parallel connection or independent connection of two modules, in the three working modes, the direct current side of the secondary side of the transformer can be connected with different distributed power supplies, energy storage and direct current loads and work independently of each other, the versatility and diversity of the topological structure are reflected, the bidirectional transmission of electric energy can be realized, the bus architecture of the true bipolar of the direct current side can meet the access requirements of different loads, power supplies and energy storage, and the simultaneous working of different loads, power supplies and energy storage is realized. The output voltage level of the alternating current side five levels is multiple, the harmonic content is low, a low-voltage-class power semiconductor device can be used, an additional DC/DC converter is not needed, the miniaturization and the light weight of equipment are realized, the high-efficiency conversion and the output of the system energy are improved, and the system can operate more stably and reliably.
Drawings
FIG. 1 is a schematic diagram of a power frequency isolation type multi-level energy router according to the present invention;
FIG. 2 is a schematic diagram of an eight-power switching tube topology of a power frequency isolation type multi-level energy router;
FIG. 3 shows PWM modulation waves of each switch in a PWM mode during a positive half period;
Fig. 4 is a diagram of a converter analysis of an eight-power switching tube topology operating in mode 1;
fig. 5 is a commutation analysis diagram of an eight-power switching tube topology operating in mode 2;
fig. 6 is a diagram of a commutation analysis of an eight-power switching tube topology operating in mode 3;
fig. 7 is a commutation analysis diagram of an eight-power switching tube topology operating in mode 4;
fig. 8 is a commutation analysis diagram of an eight-power switching tube topology operating in mode 5;
Fig. 9 is a diagram of a commutation analysis of an eight-power switching tube topology operating in mode 6;
fig. 10 is a commutation analysis diagram of an eight-power switching tube topology operating in mode 7;
fig. 11 is a diagram of a commutation analysis of an eight-power switching tube topology operating in mode 8;
FIG. 12 is a schematic diagram of a bipolar DC bus structure of each phase of a first three-phase winding on a secondary side of a power frequency isolation type multi-level energy router;
FIG. 13 is a schematic diagram of a power frequency isolated multi-level energy router in a parallel operation state;
fig. 14 is a schematic structural diagram of a power frequency isolation type multi-level energy router in a serial working state.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following examples.
In order to realize bidirectional transmission of electric energy, a direct-current side true bipolar bus architecture can meet the access requirements of different loads, power supplies and energy storage, realize simultaneous operation of different loads, power supplies and energy storage, realize that the output voltage level of the alternating-current side five levels is multiple, the harmonic content is low, and a low-voltage-class power semiconductor device can be used, so that the miniaturization and the light weight of equipment can be realized, the efficient conversion and the output of system energy are improved, and the system can operate more stably and reliably; the second three-phase winding consists of a 2、b2、c2; each two phases of the first three-phase winding are mutually independent; each two phases of the second three-phase winding are mutually independent.
The two three-phase five-level AC/DC converter modules are a first three-phase five-level AC/DC converter module and a second three-phase five-level AC/DC converter module respectively;
The first three-phase five-level AC/DC converter module consists of three single-phase five-level AC/DC converter modules, namely a first module, a second module and a third module, wherein the first module, the second module and the third module are correspondingly connected with the a 1、b1、c1 three-phase winding respectively; the second three-phase five-level AC/DC converter module consists of three single-phase five-level AC/DC converter modules, namely a fourth module, a fifth module and a sixth module, wherein the fourth module, the fifth module and the sixth module are correspondingly connected with the a 2、b2、c2 three-phase winding respectively;
The single-phase five-level AC/DC converter module is provided with three direct current buses, namely a positive bus end V up+, a zero bus end NP 1 and a negative bus end, wherein the positive bus, the negative bus and the zero bus are correspondingly connected with a first module, a second module, a third module and the positive bus, the negative bus and the zero bus in the first three-phase five-level AC/DC converter module to form three output ports of the first three-phase five-level AC/DC converter module;
And correspondingly connecting positive, negative and zero direct current buses of a fourth module, a fifth module and a sixth module in the second three-phase five-level AC/DC converter module to form three output ports of the second three-phase five-level AC/DC converter module, namely a positive bus end V down+, a zero bus end NP 2 and a negative bus end V down-. The positive, negative and zero direct current buses of the first three-phase five-level AC/DC converter module represent the positive bus of the first module, the positive bus of the second module and the positive bus of the third module, the negative bus of the first module, the negative bus of the second module and the negative bus of the third module are connected, the zero bus of the first module, the zero bus of the second module and the zero bus of the third module are connected, the positive bus of the fourth module, the positive bus of the fifth module and the positive bus of the sixth module are connected, the negative bus of the fourth module, the negative bus of the fifth module and the negative bus of the sixth module are connected, and the zero bus of the fourth module, the zero bus of the fifth module and the zero bus of the sixth module are connected.
The filter corresponding to the first three-phase five-level AC/DC converter module is a first filter, the filter corresponding to the second three-phase five-level AC/DC converter module is a second filter, the three-phase five-level AC/DC converter module is an eight-power switch tube topological structure,
The energy router comprises a positive bus end V up+, a negative bus end V down-, a zero bus end NP 1, a positive bus end V down+, a zero bus end NP 2, a negative bus end V down- and a negative bus end V up-, wherein the positive bus end V up+ is connected with the positive bus end V down+, the negative bus end V down- is connected with the negative bus end V up-, the zero bus end NP 1 is connected with the zero bus end NP 2, two three-phase windings are connected in parallel, the positive bus end V up+ and the positive bus end V up+ are positive direct current buses, the negative bus end V down- and the negative bus end V up- are negative direct current buses, the zero bus end NP 1 and the zero bus end NP 2 are zero direct current buses, and the energy router outputs 2Vdc or Vdc, and Vdc represents bus voltage;
Or the negative bus end V up- is connected with the positive bus end V down+, at the moment, two three-phase windings are connected in series, the positive bus end V up+ is an upper positive bus, the zero bus end NP 1 is an upper zero bus, the negative bus end V up- and the positive bus end V down+ are an upper negative bus-a lower positive bus, the negative bus end V down- is a lower negative bus, the zero bus end NP 2 is a lower zero bus, and the energy router outputs 4Vdc or 3Vdc or 2Vdc or Vdc;
Or the positive bus terminal V down+, the zero bus terminal NP 2 and the negative bus terminal V down-, and the positive bus terminal V up+, the zero bus terminal NP 1 and the negative bus terminal V up- are all independently disconnected, and the energy router outputs 2Vdc or Vdc.
In the PWM module, the PWM modulation wave of the positive half period is as shown in fig. 3.
The power frequency isolation transformer is provided with a primary winding and a secondary winding, the primary winding of the power frequency isolation transformer is connected with a power grid by adopting a triangle connection method, the secondary winding of the power frequency isolation transformer is formed by connecting two independent three-phase windings with the two three-phase five-level AC/DC converter modules and filters thereof in a one-to-one correspondence manner, the alternating current side of the two three-phase five-level AC/DC converter modules can output five levels, and the direct current side can lead out three direct current terminals to be connected with the positive/zero/negative three direct current buses in a one-to-one correspondence manner. The direct current side bus voltages of the two three-phase five-level AC/DC converter modules are the same, and the two three-phase five-level AC/DC converter modules can be operated in series, operated in parallel or are not connected mutually independently.
The number of the secondary windings of the power frequency isolation transformer is the same as that of the three-phase five-level AC/DC converter modules. And wherein the first three-phase winding is comprised of a 1、b1、c1 three phases; the second three-phase winding consists of a 2、b2、c2. The voltages and phases of the two secondary windings are the same, and the three windings of the three-phase winding are independent and are not connected.
Each phase of the three-phase five-level AC/DC converter module, that is, the single-phase five-level AC/DC converter module, adopts a topology structure with eight power switching tubes. An eight-power switching tube topological structure schematic diagram of the power frequency isolation type multi-level energy router is shown in fig. 2. The eight-power switching tube topological structure of the five-level AC/DC converter module specifically comprises the following components:
This type of topology comprises eight switches, two output dc side capacitors, an LCL filter or a single inductance L filter;
The first branch is formed by connecting a first power switch tube S 1 with an anti-parallel diode and a second power switch tube S 2 in series, and the drain electrode of S 2 is connected with the source electrode of S 1;
The second branch is connected with the first branch in parallel and consists of a third power switch tube S 3 with an anti-parallel diode and a fourth power switch tube S 4 which are connected in series, and the drain electrode of S 4 is connected with the source electrode of S 3;
the third branch is connected with the first branch in parallel and is formed by connecting a fifth power switch tube S 5 with an anti-parallel diode and a sixth power switch tube S 6 in series, and the drain electrode of S 6 is connected with the source electrode of S 5;
The seventh power switching tube S 7 and the eighth power switching tube S 8 with the anti-parallel diode are connected with the three branches in series, and the drain electrode of the S 8 is connected with the source electrode of the S 2、S4、S6; the source electrode of S 7 is connected with the drain electrode of S 1、S3、S5;
The fourth branch connected in parallel with the first branch is formed by connecting two capacitors C dc with the same size in series, and the midpoint of the fourth branch is connected with the midpoint of the third branch;
One end of the inductor L c is connected with the midpoint of the second branch, the other end of the inductor L f is connected with the other end of the capacitor C d;Lf and the other end of the capacitor C d;Lf is connected with the anode of the input alternating voltage; the other end of the C d is connected with the midpoint of the first branch and is also connected with the negative electrode of the input alternating voltage;
inductor L c, inductor L f, and capacitor C d make up the LCL filter.
The power switch tube is a power electronic semiconductor fully-controlled switch device, such as an Insulated Gate Bipolar Transistor (IGBT).
The power switching transistors S1, S2, S3, S4, S5, S6, S7, S8 may be insulated gate bipolar transistors and anti-parallel diodes thereof, or may be other fully-controlled power electronic switching devices. S1, S2, S3, S4 switch at a lower switching frequency in the power frequency, while S5, S6, S7, S8 switch at a higher switching frequency in the power frequency. In the invention, the lower switching frequency is about 50Hz, and the higher switching frequency can be 1K-100 KHz.
Each direct current side of the eight-power switching tube topological structure comprises positive/zero/negative three direct current buses, and the positive/zero/negative three direct current buses respectively correspond to the drain electrode of a seventh power switching tube S 7 with an anti-parallel diode, the midpoint of a series capacitor of two output direct current sides and the drain electrode of an eighth power switching tube S 8 with the anti-parallel diode;
Different distributed power supplies, direct current loads and energy storage elements can be connected between the positive bus and the zero bus, between the negative bus and the zero bus and between the positive bus and the negative bus of each eight-power switching tube topological structure.
The voltage between the positive bus and the zero bus of each eight-power switching tube topological structure is Vdc, the voltage between the negative bus and the zero bus is-Vdc, and the voltage between the positive bus and the negative bus is 2Vdc.
In the two three-phase windings of the secondary side of the transformer, the positive/zero/negative three direct current buses of a 1、b1、c1 three phases of the first three-phase winding are respectively connected to form a true bipolar direct current bus structure; and similarly, the positive/zero/negative three direct current buses of a 2、b2、c2 three phases of the second three-phase winding are respectively connected to form a true bipolar direct current bus structure.
In the two three-phase windings of the secondary side of the transformer, the DC side of each three-phase winding comprises three positive/zero/negative DC buses;
Specifically, let the output dc voltage of the first three-phase winding of the secondary side of the transformer be V up, and let the output dc voltage of the second three-phase winding be V down.
When V up is not connected to the positive/zero/negative three buses of V down independently (positive bus terminal V down+, zero bus terminal NP 2, negative bus terminal V down-, and positive bus terminal V up+, zero bus terminal NP 1, and negative bus terminal V up- are not connected independently), each module is in an independent working state, and a true bipolar dc bus structure outputting 2Vdc and Vdc can be formed independently.
When V up is connected with the positive/zero/negative three buses of V down respectively (positive bus end V up+ is connected with positive bus end V up+, negative bus end V down- is connected with negative bus end V up-, zero bus end NP 1 is connected with zero bus end NP 2), the two modules are connected in parallel on the direct current side to obtain 3 direct current buses of the positive bus, the zero bus and the negative bus, and the energy router forms a true bipolar direct current bus structure with 2Vdc and Vdc output. A schematic diagram of the bipolar dc bus is shown in fig. 12. The schematic structural diagram of the power frequency isolation type multi-level energy router in the parallel working state is shown in fig. 13.
When the negative electrode of V up is connected with the positive electrode of V down (the negative bus terminal V up- is connected with the positive bus terminal V down+), the two modules are connected in series on the direct current side, so that 5 direct current buses of an upper positive bus, an upper zero bus, an upper negative bus, a lower positive bus, a lower zero bus and a lower negative bus can be obtained, and different voltages of 4Vdc, 3Vdc, 2Vdc and Vdc can be obtained among different buses of the energy router. A schematic structural diagram of the power frequency isolation type multi-level energy router in a serial working state is shown in FIG. 14.
The energy router is in a working state of being connected in series, in parallel or in an independent mode of two modules, the direct current buses of the energy router can be respectively connected with different distributed power supplies, energy storage and direct current loads, the alternating current side is connected with a power grid, and multi-terminal energy exchange among sources, networks, storages and charges can be achieved.
The three-phase five-level isolation type AC/DC converter can realize the output of multiple voltage levels no matter in an independent working state, a serial connection state or a parallel connection working state, and can be connected with different distributed power supplies at the secondary side of the transformer in a rectifying working state, and a direct current load and an energy storage element; under the inversion working state, alternating current voltages with different voltage classes can be provided for the primary side of the transformer.
The isolated AC/DC converter can realize four-quadrant operation, taking a 1 phase in a first three-phase winding as an example, and taking the primary side voltage of a transformer asThe secondary side output voltage of the transformer isWhen (when)Lag behindWhen the converter is in rectifying state, the original AC power supply outputs active powerLeading ahead ofWhen the converter is in an inversion state, active power is input into the primary side alternating current power supply.
The energy router can realize bidirectional output of electric energy, and the direct-current side true bipolar bus architecture can meet the access requirements of different loads, power supplies and energy storage, so that simultaneous work of different loads, power supplies and energy storage is realized;
The output voltage level of the alternating-current side five levels is multiple, the harmonic content is low, and a low-voltage-class power semiconductor device can be used, so that the miniaturization and the light weight of equipment are realized, the high-efficiency conversion and the output of the system energy are improved, and the system can operate more stably and reliably.
In the invention, the three-phase five-level isolation type AC/DC converter module can adopt Sinusoidal Pulse Width Modulation (SPWM) or space vector modulation (SVPWM), and the two groups of three-phase five-level isolation type AC/DC converter modules have the same modulation mode.
The invention has the advantages that:
(1) The isolated energy router adopts a multi-level design, can fully utilize three-phase alternating current input voltage, reduces energy waste and improves rectification efficiency.
(2) The isolated energy router can realize more stable direct-current voltage output and finer power adjustment, and greatly improves the conversion efficiency and the service life of the rectifier.
(3) The isolated energy router is suitable for the fields of direct current power supply, alternating current power supply and the like, and can meet the requirements of different industries and fields.
(4) The two three-phase windings on the secondary side of the isolated energy router can work in three working modes of series connection, parallel connection or independent connection of the two modules, in the three working modes, the direct current side of the secondary side of the transformer can be connected with different distributed power supplies, energy storage and direct current loads and work independently of each other, and the versatility and the diversity of the topological structure are reflected.
(5) The isolated energy router can realize bidirectional transmission of electric energy, and the direct-current side true bipolar bus architecture can meet the access requirements of different loads, power supplies and energy storage, so that simultaneous work of different loads, power supplies and energy storage is realized. The output voltage level of the alternating-current side five levels is multiple, the harmonic content is low, and a low-voltage-class power semiconductor device can be used, so that the miniaturization and the light weight of equipment are realized, the high-efficiency conversion and the output of the system energy are improved, and the system can operate more stably and reliably.
The power switching transistor S 1、S2、S3、S4、S5、S6、S7、S8 is an insulated gate bipolar transistor.
In order to describe the mode of operation, the following assumptions are made:
(1) Neglecting leakage inductance and winding resistance of the isolation transformer;
(2) Neglecting the inductance and winding resistance of the balancing reactor;
(3) The diode connected with the single-phase rectifier bridge is an ideal device;
(4) The system operates in a high inductive load state.
(5) The power switching tubes S1-S8 work at the resonant frequency, and dead time is ignored;
(6) The converter is designed in a continuous Current Conduction Mode (CCM);
taking any one of two three-phase windings as an example, the working mode of the five-level AC/DC converter module is as follows:
1) Modality 1: [ t0-t1]
As shown in fig. 4, the switching transistors S 2、S3、S6 and S 7 are turned on; s 1、S4、S5 and S 8 are turned off, and the output dc voltage is Vdc.
2) Modality 2: [ t1-t2]
As shown in fig. 5, the switching transistors S 2、S3、S7 and S 8 are turned on; s 1、S4、S5 and S 7 are turned off, and the output direct-current voltage is 2Vdc.
3) Modality 3: [ t2-t3]
As shown in fig. 6, when the switching transistors S 2、S3、S5 and S 8 are turned on; s 1、S4、S6 and S 7 are turned off, and the dc voltage Vdc is output.
4) Modality 4: [ t3-t4]
As shown in fig. 7, when the switching transistors S 2、S3、S5 and S 8 are turned on; s 1、S4、S6 and S 7 are turned off; the output dc voltage is 0.
5) Modality 5: [ t4-t5]
As shown in fig. 8, the switching transistors S 1、S3、S6 and S 7 are turned on; s 2、S4、S5 and S 8 are turned off, and the output direct-current voltage is-Vdc.
6) Modality 6: [ t5-t6]
As shown in fig. 9, the switching transistors S 1、S4、S6 and S 7 are turned on; s 2、S3、S5 and S 8 are turned off, and the output direct-current voltage is-2 Vdc.
7) Modality 7: [ t6-t7]
As shown in fig. 10, when the switching transistors S 2、S4、S6 and S 7 are turned on; s 1、S3、S5 and S 8 are turned off, and a dc voltage-Vdc is output.
8) Modality 8: [ t7-t8]
As shown in fig. 11, when the switching transistors S 2、S3、S6 and S 7 are turned on; s 1、S4、S5 and S 8 are turned off; the output dc voltage is 0.
Each eight-power switch tube topological structure direct current side comprises three positive/zero/negative direct current buses, and the positive/zero/negative three direct current buses correspond to the drain electrode of a seventh power switch tube S7 with an anti-parallel diode, the midpoint of a series capacitor of two output direct current sides and the source electrode of an eighth power switch tube S8 with the anti-parallel diode respectively.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.

Claims (10)

1.一种工频隔离型多电平能量路由器，其特征在于，所述路由器包括三相绕组工频隔离变压器、两个三相五电平AC/DC变流器模块和与每个变流器模块对应的滤波器，其中，所述工频隔离变压器具有原边绕组和副边绕组，所述工频隔离变压器的原边绕组采用三角形接法与电网相连接，所述工频隔离变压器的副边绕组为两个独立的三相绕组，分别为第一三相绕组和第二三相绕组，两个三相绕组分别与两个三相五电平AC/DC变流器模块连接，所述第一三相绕组由a1、b1、c1三相组成；所述第二三相绕组由a2、b2、c2组成；所述第一三相绕组的每两相之间相互独立；所述第二三相绕组的每两相之间相互独立。1. A power frequency isolation type multi-level energy router, characterized in that the router comprises a three-phase winding power frequency isolation transformer, two three-phase five-level AC/DC converter modules and a filter corresponding to each converter module, wherein the power frequency isolation transformer has a primary winding and a secondary winding, the primary winding of the power frequency isolation transformer is connected to the power grid in a delta connection, the secondary winding of the power frequency isolation transformer is two independent three-phase windings, namely a first three-phase winding and a second three-phase winding, the two three-phase windings are respectively connected to two three-phase five-level AC/DC converter modules, the first three-phase winding is composed of three phases a1 , b1 , and c1 ; the second three-phase winding is composed of a2 , b2 , and c2 ; each two phases of the first three-phase winding are independent of each other; each two phases of the second three-phase winding are independent of each other. 所述两个三相五电平AC/DC变流器模块分别为第一三相五电平AC/DC变流器模块和第二三相五电平AC/DC变流器模块；The two three-phase five-level AC/DC converter modules are respectively a first three-phase five-level AC/DC converter module and a second three-phase five-level AC/DC converter module; 所述第一三相五电平AC/DC变流器模块由三个单相五电平AC/DC变流器模块组成，分别为模块一、模块二、模块三，模块一、模块二、模块三分别与a1、b1、c1三相绕组对应连接；所述第二三相五电平AC/DC变流器模块由三个单相五电平AC/DC变流器模块组成，分别为模块四、模块五、模块六，模块四、模块五、模块六分别与a2、b2、c2三相绕组对应连接；The first three-phase five-level AC/DC converter module is composed of three single-phase five-level AC/DC converter modules, namely module one, module two, and module three, and module one, module two, and module three are respectively connected to the three-phase windings a1 , b1 , and c1 ; the second three-phase five-level AC/DC converter module is composed of three single-phase five-level AC/DC converter modules, namely module four, module five, and module six, and module four, module five, and module six are respectively connected to the three-phase windings a2 , b2 , and c2 ; 所述单相五电平AC/DC变流器模块具有正、负、零三根直流母线，模块一、模块二、模块三的正、负、零三根直流母线对应连接，形成第一三相五电平AC/DC变流器模块的三个输出端口，分别为正母线端Vup+、零母线端NP1和负母线端；The single-phase five-level AC/DC converter module has three DC buses, namely, positive, negative and zero. The positive, negative and zero DC buses of module one, module two and module three are connected correspondingly to form three output ports of the first three-phase five-level AC/DC converter module, namely, the positive bus terminal V up+ , the zero bus terminal NP 1 and the negative bus terminal; 模块四、模块五、模块六的正、负、零三根直流母线对应连接，形成第二三相五电平AC/DC变流器模块的三个输出端口，分别为正母线端Vdown+、零母线端NP2和负母线端Vdown-；The positive, negative and zero DC bus bars of module four, module five and module six are connected correspondingly to form three output ports of the second three-phase five-level AC/DC converter module, which are respectively the positive bus terminal V down+ , the zero bus terminal NP 2 and the negative bus terminal V down- ; 所述第一三相五电平AC/DC变流器模块对应的滤波器为第一滤波器，所述第二三相五电平AC/DC变流器模块对应的滤波器为第二滤波器，三相五电平AC/DC变流器模块为八功率开关管拓扑结构，The filter corresponding to the first three-phase five-level AC/DC converter module is a first filter, the filter corresponding to the second three-phase five-level AC/DC converter module is a second filter, and the three-phase five-level AC/DC converter module is an eight-power switch tube topology structure. 其中，正母线端Vup+连接正母线端Vdown+，负母线端Vdown-连接负母线端Vup-，零母线端NP1连接零母线端NP2，此时两个三相绕组并联，正母线端Vup+和正母线端Vup+为正直流母线，负母线端Vdown-和负母线端Vup-为负直流母线，零母线端NP1和零母线端NP2为零直流母线，能量路由器输出2Vdc或Vdc，Vdc表示母线电压；Among them, the positive bus terminal V up+ is connected to the positive bus terminal V down+ , the negative bus terminal V down- is connected to the negative bus terminal V up- , and the zero bus terminal NP 1 is connected to the zero bus terminal NP 2. At this time, the two three-phase windings are connected in parallel, the positive bus terminal V up+ and the positive bus terminal V up+ are the positive DC bus, the negative bus terminal V down- and the negative bus terminal V up- are the negative DC bus, the zero bus terminal NP 1 and the zero bus terminal NP 2 are the zero DC bus, and the energy router outputs 2Vdc or Vdc, and Vdc represents the bus voltage; 或负母线端Vup-连接正母线端Vdown+，此时两个三相绕组串联，正母线端Vup+为上正母线，零母线端NP1为上零母线，负母线端Vup-和正母线端Vdown+为上负母线-下正母线，负母线端Vdown-为下负母线，零母线端NP2为下零母线，能量路由器输出4Vdc或3Vdc或2Vdc或Vdc；Or the negative bus terminal V up- is connected to the positive bus terminal V down+ , at this time, the two three-phase windings are connected in series, the positive bus terminal V up+ is the upper positive bus, the zero bus terminal NP 1 is the upper zero bus, the negative bus terminal V up- and the positive bus terminal V down+ are the upper negative bus-lower positive bus, the negative bus terminal V down- is the lower negative bus, the zero bus terminal NP 2 is the lower zero bus, and the energy router outputs 4Vdc or 3Vdc or 2Vdc or Vdc; 或正母线端Vdown+、零母线端NP2和负母线端Vdown-，以及正母线端Vup+、零母线端NP1和负母线端Vup-均独立不连接，能量路由器输出2Vdc或Vdc。Or the positive bus terminal V down+ , the zero bus terminal NP 2 and the negative bus terminal V down- , as well as the positive bus terminal V up+ , the zero bus terminal NP 1 and the negative bus terminal V up- are all independent and not connected, and the energy router outputs 2Vdc or Vdc. 2.根据权利要求1所述的一种工频隔离型多电平能量路由器，其特征在于，所述三相五电平AC/DC变流器模块的每一相均为八功率开关管拓扑结构，所述八功率开关管拓扑结构包括八个开关和两个输出直流侧电容，八功率开关管拓扑结构分为第一支路、第二支路、第三支路和第四支路。2. According to claim 1, a power frequency isolation type multi-level energy router is characterized in that each phase of the three-phase five-level AC/DC converter module is an eight-power switch tube topology structure, the eight-power switch tube topology structure includes eight switches and two output DC side capacitors, and the eight-power switch tube topology structure is divided into a first branch, a second branch, a third branch and a fourth branch. 3.根据权利要求2所述的一种工频隔离型多电平能量路由器，其特征在于，所述八个开关分别为第一功率开关管S1、第二功率开关管S2、三功率开关管S3、第四功率开关管S4、第五功率开关管S5、第六功率开关管S6、第七功率开关管S7和第八功率开关管S8；3. The power frequency isolation type multi-level energy router according to claim 2, characterized in that the eight switches are respectively a first power switch tube S 1 , a second power switch tube S 2 , a third power switch tube S 3 , a fourth power switch tube S 4 , a fifth power switch tube S 5 , a sixth power switch tube S 6 , a seventh power switch tube S 7 and an eighth power switch tube S 8 ; 所述第一支路由的第一功率开关管S1、第二功率开关管S2串联组成，并且第二功率开关管S2的漏极与第一功率开关管S1的源极相连；The first branch is composed of a first power switch tube S 1 and a second power switch tube S 2 connected in series, and the drain of the second power switch tube S 2 is connected to the source of the first power switch tube S 1 ; 所述第二支路与第一支路并联，第二支路由第三功率开关管S3和第四功率开关管S4串联组成，第四功率开关管S4的漏极与第三功率开关管S3的源极相连；The second branch is connected in parallel with the first branch, the second branch is composed of a third power switch tube S3 and a fourth power switch tube S4 connected in series, and the drain of the fourth power switch tube S4 is connected to the source of the third power switch tube S3 ; 所述第三支路与第一支路并联，第三支路由第五功率开关管S5和第六功率开关管S6串联组成，第六功率开关管S6的漏极与第五功率开关管S5的源极相连；The third branch is connected in parallel with the first branch, and the third branch is composed of a fifth power switch tube S5 and a sixth power switch tube S6 connected in series, and the drain of the sixth power switch tube S6 is connected to the source of the fifth power switch tube S5 ; 第七功率开关管S7和第八功率开关管S8与第一支路、第二支路和第三支路串联；The seventh power switch tube S7 and the eighth power switch tube S8 are connected in series with the first branch, the second branch and the third branch; 所述第四支路由两个大小相等的电容Cdc组成，第四支路的中点连接于第三支路的中点。The fourth branch is composed of two capacitors C dc of equal size, and the midpoint of the fourth branch is connected to the midpoint of the third branch. 4.根据权利要求3所述的一种工频隔离型多电平能量路由器，其特征在于，所述第八功率开关管S8的漏极与第二功率开关管S2、第四功率开关管S4和第六功率开关管S6的源极相连，第七功率开关管S7的源极与第一功率开关管S1、第三功率开关管S3和第五功率开关管S5的漏极相连。4. The power frequency isolation multi-level energy router according to claim 3, characterized in that the drain of the eighth power switch tube S8 is connected to the source of the second power switch tube S2 , the fourth power switch tube S4 and the sixth power switch tube S6 , and the source of the seventh power switch tube S7 is connected to the drain of the first power switch tube S1 , the third power switch tube S3 and the fifth power switch tube S5 . 5.根据权利要求4所述的一种工频隔离型多电平能量路由器，其特征在于，第七功率开关管S7的漏极连接正母线端，第八功率开关管S8的源极连接负母线端，两个大小相等的电容质检的连接处为零母线端。5. The power frequency isolation multi-level energy router according to claim 4 is characterized in that the drain of the seventh power switch tube S7 is connected to the positive bus terminal, the source of the eighth power switch tube S8 is connected to the negative bus terminal, and the connection point of the two capacitors of equal size is the zero bus terminal. 6.根据权利要求2所述的一种工频隔离型多电平能量路由器，其特征在于，所述三相五电平AC/DC变流器模块的对应的滤波器为单电感L滤波器或者LCL滤波器，LCL滤波器由电感Lc、电感Lf以及电容Cd组成。6. A power frequency isolation multi-level energy router according to claim 2, characterized in that the corresponding filter of the three-phase five-level AC/DC converter module is a single inductor L filter or an LCL filter, and the LCL filter is composed of an inductor L c , an inductor L f and a capacitor C d . 7.根据权利要求6所述的一种工频隔离型多电平能量路由器，其特征在于，电感Lc的一端连接于第二支路中点，电感Lc的另一端连接于电感Lf的一端和电容Cd的一端，Lf的另一端连接于输入交流电压正极Vin+，Cd的另一端连接于第一支路中点，并连接交流电压负极Vin-。7. A power frequency isolation type multi-level energy router according to claim 6, characterized in that one end of the inductor L c is connected to the midpoint of the second branch, the other end of the inductor L c is connected to one end of the inductor L f and one end of the capacitor C d , the other end of L f is connected to the positive input AC voltage Vin + , and the other end of C d is connected to the midpoint of the first branch and connected to the negative AC voltage Vin- . 8.根据权利要求3所述的一种工频隔离型多电平能量路由器，其特征在于，功率开关管为带有反并联二极管的绝缘栅双极晶体管。8. The power frequency isolation type multi-level energy router according to claim 3, characterized in that the power switch tube is an insulated gate bipolar transistor with an anti-parallel diode. 9.根据权利要求8所述的一种工频隔离型多电平能量路由器，其特征在于，第一功率开关管S1、第二功率开关管S2、三功率开关管S3和第四功率开关管S4在工频频率内以较低的开关频率进行开关，第五功率开关管S5、第六功率开关管S6、第七功率开关管S7和第八功率开关管S8在工频频率内以较高的开关频率进行开关。9. The power frequency isolation type multi-level energy router according to claim 8, characterized in that the first power switch tube S1 , the second power switch tube S2 , the third power switch tube S3 and the fourth power switch tube S4 are switched at a lower switching frequency within the power frequency, and the fifth power switch tube S5 , the sixth power switch tube S6 , the seventh power switch tube S7 and the eighth power switch tube S8 are switched at a higher switching frequency within the power frequency. 10.根据权利要求1所述的一种工频隔离型多电平能量路由器，其特征在于，三相五电平AC/DC变流器模块的同一相内，其正母线端和零母线端之间的电压为Vdc，负母线端与零母线端之间电压为-Vdc，正母线端与负母线端之间电压为2Vdc。10. The power frequency isolation multi-level energy router according to claim 1 is characterized in that, in the same phase of the three-phase five-level AC/DC converter module, the voltage between the positive bus terminal and the zero bus terminal is Vdc, the voltage between the negative bus terminal and the zero bus terminal is -Vdc, and the voltage between the positive bus terminal and the negative bus terminal is 2Vdc.
CN202410534125.6A 2024-04-30 2024-04-30 A power frequency isolation type multi-level energy router Pending CN118381341A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119010615A (en) * 2024-08-19 2024-11-22 湖南大学 Electrolytic power supply based on high-frequency transformation

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119010615A (en) * 2024-08-19 2024-11-22 湖南大学 Electrolytic power supply based on high-frequency transformation

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