CN109038693A - A kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology and its control method - Google Patents
A kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology and its control method Download PDFInfo
- Publication number
- CN109038693A CN109038693A CN201810827102.9A CN201810827102A CN109038693A CN 109038693 A CN109038693 A CN 109038693A CN 201810827102 A CN201810827102 A CN 201810827102A CN 109038693 A CN109038693 A CN 109038693A
- Authority
- CN
- China
- Prior art keywords
- mmc
- bridge
- pressure side
- submodule
- transformer
- 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
Links
Classifications
-
- 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
- H02J5/00—Circuit arrangements for transfer of electric power between ac networks and dc networks
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
The invention discloses a kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topologies and its control method.The present invention can only use the AC transformer of a 1:1 in the case where realizing the interconnection of multiple and different voltage levels direct current power grids inside commutator transformer.Compared to existing commutator transformer scheme, the present invention only uses an AC transformer, can substantially reduce the volume weight of equipment, simplifies structure；The present invention need to can be adapted to the DC grid of different voltages grade only by adjusting control strategy, improve the flexibility of multiterminal element transformer, reduce operation expense.
Description
Technical field
The invention belongs to high power DC transformer technology field, in particular to a kind of power distribution network based on MMC structure is used
Multiterminal no-load voltage ratio adjustable DC transformer topology and its control method.
Background technique
In recent years, energy demand constantly increases, and the ratio of distributed energy is also higher and higher in power grid, and DC grid is regarded
For the key for building large capacity transmission system.In traditional HVDC transmission system, 2 end direct current transportation are only able to achieve a little pair
The direct current energy transmission of point, with the construction of economic development and power grid, the DC grid in inevitable requirement future can be realized mostly electric
Source power supply and multiple spot are realized the connection between different voltages grade DC grid by electricity.Therefore, commutator transformer becomes direct current
Key link in power grid.
Currently, educational circles proposes many high-capacity direct current converter topologies, it is by high frequency transformer connection two mostly
A DC/AC converter.The DC line interconnection of two different voltages grades may be implemented using the commutator transformer of this structure.
However to cope with the demand of the following DC distribution net, the DC bus of multiple and different voltage class needs to be connected with each other, therefore needs
Want the multiterminal element transformer of large capacity.Compared to both ends commutator transformer, multiterminal element transformer can connect multiple and different
The DC bus of voltage class is suitable for DC distribution net.
Therefore, it is necessary to study multiterminal element transformer topology on the basis of the commutator transformer of both ends.And traditional straight
In convertor transformer, voltage change ratio is realized by AC transformer, then multiterminal element inside transformer needs multiple AC transformers,
Cause the quantity of AC transformer to increase, also increases the volume weight of equipment.
Summary of the invention
Aiming at the problems existing in the prior art, the object of the present invention is to provide one kind to be based on MMC (Modular
Multilevel Converter) structure power distribution network multiterminal no-load voltage ratio adjustable DC transformer topology and its control method, phase
Than the multiterminal element transformer based on multiple AC transformers, it is somebody's turn to do the multiterminal element inside transformer based on MMC structure and only needs
The AC transformer of one 1:1, therefore simplify structure, AC transformer quantity is saved, reduces device volume, and due to it
No-load voltage ratio regulating power need to only adjust corresponding control strategy and hand over without replacing when DC grid voltage class changes
Convertor transformer, flexibility is high, can reduce operation and maintenance cost.
To achieve the goals above, the technical solution adopted by the present invention is that, a kind of power distribution network multiterminal based on MMC structure
No-load voltage ratio adjustable DC transformer topology, including a k low-pressure side MMC and high-pressure side MMC；The DC side of k low-pressure side MMC point
Each DC grid is not connected, is connected to AC transformer after exchange side is in parallel, connects high-pressure side direct current after high-pressure side MMC rectification
Power grid, wherein k >=2；An equivalent inductance L is connected separately between each low-pressure side MMC and AC transformereq。
Submodule on each bridge arm of low-pressure side MMC and high-pressure side MMC is half-bridge module.
The low-pressure side MMC and high-pressure side MMC is all made of four bridge legs MMC, and four bridge arms form symmetrical full H bridge structure,
And the upper and lower bridge arm of full H bridge structure intersects to form two groups of circuits, wherein each bridge arm is by several identical numbers in the same MMC
The half-bridge MMC sub-module cascade of amount forms.
The no-load voltage ratio of the AC transformer is 1:1.
The invention also discloses a kind of controls of multiterminal no-load voltage ratio adjustable DC transformer topology of power distribution network based on MMC structure
Method processed, MMC have four bridge arms of intersection, have n submodule on each bridge arm, control method specifically includes the following steps:
The exchange side voltage value U of step 1) setting low-pressure side MMCac, according to each low-pressure side MMC DC voltage Udc, calculate
It exchanges side voltage UacWith DC voltage UdcRatio, wherein the first bridge arm and four bridge legs are a pair of cross bridge arm,
Second bridge arm and four bridge legs are second pair of intersection bridge arm, and the mould of current MMC a pair of cross bridge arm conducting is determined by following formula
S and second pair of number intersects the number of modules m that bridge arm is connected:
In formula: UvaFor the level of current the first and second bridge arm of low-pressure side MMC leading point, UvbFor current low-pressure side MMC third,
The level of four bridge legs leading point.
Step 2) is generated the square-wave signal and two opposite 1 Hes of submodule driving signal that the period is T by signal generator
2, wherein driving signal 1 is to put into submodule, and driving signal 2 is to cut off submodule；
Two driving signals of step 2) are sent into each half-bridge submodule by step 3), according to the voltage of each module of acquisition,
Ascending sort is carried out, according to ranking results, m the and s value for each MMC being calculated according to step 1) opens the son of corresponding number
Module keeps the exchange side voltage of each low-pressure side MMC equal；
Step 4) needs the power exported according to each low-pressure side MMC, calculates respective phase shifting angle δ, makes equivalent inductance LeqTwo
Holding ac square wave phase difference is that δ transmits power.
When square-wave signal is high level, the smallest s half-bridge submodule input of voltage is driven in the bridge arm of a pair of cross
Dynamic waveform 1, remaining n-s half-bridge submodule input drive waveforms 2, the smallest m of voltage half in the bridge arm of second pair of intersection
Bridge submodule inputs drive waveforms 1, and remaining n-m half-bridge submodule inputs drive waveforms 2；
When square-wave signal is low level, the smallest n-m half-bridge submodule input of voltage in the bridge arm of a pair of cross
Drive waveforms 1, remaining m half-bridge submodule input drive waveforms 2；The smallest n-s of voltage in the bridge arm of second pair of intersection
Half-bridge submodule inputs drive waveforms 1, and remaining s half-bridge submodule inputs drive waveforms 2.
The present invention is based on the multiterminal no-load voltage ratio adjustable dc voltage device topologys and its control method of proposition, control interstage exchange side
The alternating voltage amplitude at each MMC exchange end is equal, so that in interstage exchange transformer after multiple ports MMC connection equivalent inductance
Side is in parallel, and the watt level of each port transmission is controlled by the phase difference δ before and after inductance.
Compared with prior art, the present invention at least has the advantages that the invention discloses one kind based on MMC structure
Distribution multiterminal no-load voltage ratio adjustable DC transformer topology and its control method.The program can realize multiple and different voltages etc.
In the case where the interconnection of grade DC grid, the AC transformer of a 1:1 is only used inside commutator transformer.Compared to existing
Commutator transformer scheme, the present invention can substantially reduce the volume weight of equipment, simplify structure；The program only need to be by adjusting control
System strategy can be adapted to the DC grid of different voltages grade, improve the flexibility of multiterminal element transformer, reduce operation
Maintenance cost.
Further, technical solution proposed by the invention realizes the multiterminal change for only using a 1:1 AC transformer
Than adjustable DC transformer topology, by corresponding control method, so that each port MMC alternating voltage phase that DC voltage is different
Deng, it is in parallel after equivalent inductance, the phase shifting angle that each port needs is calculated according to the difference of transimission power, and control accordingly equivalent
The phase difference that two sections of inductance is with transimission power.
Therefore when each low-pressure side DC voltage difference, change the submodule number of conducting according to the control method proposed
M, s makes to exchange side UacVoltage magnitude is equal, allows multiple low pressure MMC in parallel in exchange side.
Detailed description of the invention
Fig. 1 is the multiterminal no-load voltage ratio adjustable DC transformer topology schematic diagram based on MMC structure.
The position Fig. 2 MMC half-bridge submodule schematic diagram.
Fig. 3 is inverter control method schematic diagram.
Fig. 4 is the control of each bridge arm submodule and modulation program flow chart, and wherein Fig. 4 a is 1,4 bridge arm programs；Fig. 4 b is 2,3
Bridge arm program.
Fig. 5 is equivalent inductance transimission power schematic diagram.
Fig. 6 is device input and output simulation waveform.
Fig. 7 is device interstage exchange side simulation waveform.
Specific embodiment
The present invention will be further described With reference to embodiment.
A kind of multiterminal no-load voltage ratio adjustable DC transformer topology and its control method based on MMC structure proposed by the present invention,
Using the control strategy for not depending on AC transformer no-load voltage ratio.The DC side of each MMC is separately connected the direct current of different voltages grade
Power grid, the on-off for adjusting each bridge arm Neutron module keep the voltage of exchange side constant, the exchange through 1:1 after exchange side parallel connection collects
Transformer is connected to the side high pressure MMC, accesses high-pressure side DC grid after high-pressure side MMC rectification.This programme can be by flexible
The on-off number for adjusting each bridge arm module in topology changes voltage change ratio, to connect the DC grid of different voltages grade.Emulation knot
Fruit is as shown in Fig. 6.
Topological structure of the invention is as shown in Figure 1, all by multiple half-bridge MMC submodules at the every Single port of multiterminal element transformer
Block cascade composition, MMC1~MMCk are k low-pressure side MMC, and DC side connects each DC grid, and equivalent inductance L is crossed in exchange sideeq
It is in parallel afterwards, then connected through 1:1 AC transformer, high-pressure side DC grid is connected after high-pressure side MMC rectification；U in figuredc1~Udck
For each low-pressure side DC voltage；UdchFor high-pressure side DC voltage；Leq1~LeqkFor equivalent inductance；L1~L4For bridge arm inductance；
Arm1~Arm4 is each bridge arm of MMC；SM1~SMn, SM1~SMm, SM1~SMp are MMC submodule, submodule such as Fig. 2 institute
Show, each submodule is by T1、T2Two backward dioded D in parallel1、D2IGBT series connection after submodule capacitor C in parallel.
As shown in Figure 1, the present invention includes k low-pressure side MMC and a high-pressure side MMC；The DC side of k low-pressure side MMC
It is separately connected each DC grid, is connected to AC transformer after exchange side is in parallel, connection high-pressure side is straight after high-pressure side MMC rectification
Galvanic electricity net, wherein k >=2；An equivalent inductance L is connected separately between each low-pressure side MMC and AC transformereq；Low-pressure side
MMC and high-pressure side MMC includes to be provided with bridge arm inductance on each bridge arm there are four bridge arm；Submodule on each bridge arm
For half-bridge module.
The multiterminal no-load voltage ratio adjustable DC transformer topology mentioned for the present invention is passed through using transformer voltage ratio is not depended on
Each bridge arm on-off of flexible modulation topology changes the control strategy of voltage.
As shown in Figure 1, each MMC has four bridge arms of intersection, the control strategy of proposition specifically includes the following steps:
(1) alternating voltage grade according to demand calculates the voltage ratio of output with input, is determined according to the voltage ratio
The modulus s and m of the bridge arm conducting of the every a pair of cross of current MMC, the numerical value determination of s and m determine that ratio is closed by following formula first
System determines the proportionate relationship between m-s and m+s, then selects on bridge arm the maximum value of m and s within submodule number n:
(2) square-wave signal and two opposite submodule driving signals 1 and 2 that the period is T are generated by signal generator,
In, driving signal 1 is to put into submodule, and driving signal 2 is to cut off submodule；
(3) two driving signals each half-bridge submodule is sent into be ranked up, root according to the voltage of each module of acquisition
According to the lesser several modules of ranking results turning-on voltage, keep the exchange side voltage magnitude of each MMC equal；
(4) as shown in figure 3, calculating phase shifting angle δ according to each DC voltage of outlet side and the power for needing to export, making equivalent
Inductance both ends ac square wave phase difference is δ, and to transmit power, in conjunction with Fig. 5, equivalent inductance power transfer formula isWherein ω is the angular frequency for exchanging side wave, and Leq is the size of equivalent inductance；Uac1Before equivalent inductance
Alternating voltage amplitude；Uac2For the alternating voltage amplitude before equivalent inductance.
By taking the side MMC for having n submodule as an example, as shown in Figure 4: when square-wave signal is high level, for first pair
For the bridge arm of intersection, the smallest s module of voltage inputs drive waveforms 1, and remaining n-s module inputs drive waveforms 2；It is right
In second for the bridge arm intersected, the smallest m module of voltage inputs drive waveforms 1, remaining n-m module input driving
Waveform 2；
When square-wave signal is low level, for the bridge arm of a pair of cross, the smallest n-m module input of voltage
Drive waveforms 1, remaining m module input drive waveforms 2；For second for the bridge arm intersected, voltage the smallest n-s
Module inputs drive waveforms 1, and remaining s module inputs drive waveforms 2.
Therefore when each low-pressure side DC voltage difference, change submodule the number m and s of conducting, make to exchange side UacVoltage
Amplitude is equal；According to each DC voltage of outlet side and the power for needing to export, each low-pressure side MMC AC wave shape and high-pressure side are calculated
The phase difference δ of AC wave shape1, δ2……δk, the phase shifting angle of each low pressure MMC is controlled, is exported.
The commutator transformer topology simulation model of proposition, simulation model mesolow side are established in MATLAB/Simulink
There are two MMC, the DC voltage of two low pressure MMC is respectively 10kV, and 15kV, the DC voltage of the side high pressure MMC is 25kV, figure
7 show exchange side voltage waveform, and Vac_pri_1, Vac_pri_2 are respectively the AC port voltage waveform of low-pressure side MMC,
Vac_sec is the AC port voltage waveform of high-pressure side MMC, therefore, using the control method of proposition, although low pressure MMC's is straight
Galvanic electricity pressure differs, and each port exchange side voltage magnitude is controllably ± 5kV in figure, and each port DC voltage as shown in fig. 6,
Demonstrate proposed topology and control method.
Claims (6)
1. a kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology, which is characterized in that including k
A low-pressure side MMC and high-pressure side MMC；The DC side of k low-pressure side MMC is separately connected each DC grid, after exchange side is in parallel
It is connected to AC transformer, connects high-pressure side DC grid after high-pressure side MMC rectification, wherein k >=2；Each low-pressure side MMC
An equivalent inductance L is connected separately between AC transformereq。
2. a kind of power distribution network based on MMC structure according to claim 1 multiterminal no-load voltage ratio adjustable DC transformer topology,
It is characterized in that, the submodule on each bridge arm of low-pressure side MMC and high-pressure side MMC is half-bridge module.
3. a kind of power distribution network based on MMC structure according to claim 1 multiterminal no-load voltage ratio adjustable DC transformer topology,
It is characterized in that, the low-pressure side MMC and high-pressure side MMC are all made of four bridge legs MMC, the symmetrical full H bridge knot of four bridge arm compositions
Structure, and the upper and lower bridge arm of full H bridge structure intersects to form two groups of circuits, wherein each bridge arm is by several phases in the same MMC
Half-bridge MMC sub-module cascade with quantity forms.
4. a kind of power distribution network based on MMC structure according to claim 1 multiterminal no-load voltage ratio adjustable DC transformer topology,
It is characterized in that, the no-load voltage ratio of the AC transformer is 1:1.
5. a kind of power distribution network based on MMC structure according to any one of claims 1 to 4 multiterminal no-load voltage ratio straight-adjustable rheology
The control method of depressor topology, which is characterized in that MMC has four bridge arms of intersection, has n submodule on each bridge arm, control
Method specifically includes the following steps:
The exchange side voltage value U of step 1) setting low-pressure side MMCac, according to each low-pressure side MMC DC voltage Udc, calculate its friendship
Flow side voltage UacWith DC voltage UdcRatio, wherein the first bridge arm and four bridge legs are a pair of cross bridge arm, second
Bridge arm and four bridge legs are second pair of intersections bridge arm, by following formula determine the modulus s of current MMC a pair of cross bridge arm conducting with
Second pair intersects the number of modules m that bridge arm is connected:
In formula: UvaFor the level of current the first and second bridge arm of low-pressure side MMC leading point, UvbFor current third and fourth bridge of low-pressure side MMC
The level of arm leading point；
Step 2) is generated the square-wave signal and two opposite submodule driving signals 1 and 2 that the period is T by signal generator,
In, driving signal 1 is to put into submodule, and driving signal 2 is to cut off submodule；
Two driving signals of step 2) are sent into each half-bridge submodule by step 3), according to the voltage of each module of acquisition, are carried out
Ascending sort, according to ranking results, m the and s value for each MMC being calculated according to step 1) opens the submodule of corresponding number
Block keeps the exchange side voltage of each low-pressure side MMC equal；
Step 4) needs the power exported according to each low-pressure side MMC, calculates respective phase shifting angle δ, makes equivalent inductance LeqIt hands at both ends
Flowing square wave phase difference is that δ transmits power.
6. control method according to claim 5, which is characterized in that when square-wave signal is high level, a pair of cross
Bridge arm in the smallest s half-bridge submodule of voltage input drive waveforms 1, remaining n-s half-bridge submodule input drives wave
Shape 2, the smallest m half-bridge submodule of voltage inputs drive waveforms 1 in the bridge arm of second pair of intersection, and remaining n-m half-bridge is sub
Module inputs drive waveforms 2；
When square-wave signal is low level, the smallest n-m half-bridge submodule input driving of voltage in the bridge arm of a pair of cross
Waveform 1, remaining m half-bridge submodule input drive waveforms 2；The smallest n-s half-bridge of voltage in the bridge arm of second pair of intersection
Submodule inputs drive waveforms 1, and remaining s half-bridge submodule inputs drive waveforms 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810827102.9A CN109038693A (en) | 2018-07-25 | 2018-07-25 | A kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology and its control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810827102.9A CN109038693A (en) | 2018-07-25 | 2018-07-25 | A kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology and its control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109038693A true CN109038693A (en) | 2018-12-18 |
Family
ID=64645068
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810827102.9A Pending CN109038693A (en) | 2018-07-25 | 2018-07-25 | A kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology and its control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109038693A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103036451A (en) * | 2013-01-16 | 2013-04-10 | 广东电网公司电力科学研究院 | Electronic power transformer |
| CN204131408U (en) * | 2014-09-24 | 2015-01-28 | 华中科技大学 | A kind of MMC type commutator transformer based on multi winding transformer coupling |
| JP2016063688A (en) * | 2014-09-19 | 2016-04-25 | 株式会社東芝 | Power conversion device |
| CN105896585A (en) * | 2016-04-28 | 2016-08-24 | 南方电网科学研究院有限责任公司 | AC side fault ride-through control method for hybrid multi-terminal DC power transmission system |
| CN106230269A (en) * | 2016-09-20 | 2016-12-14 | 西安交通大学 | A kind of dcdc converter modulator approach based on MMC |
| CN106253728A (en) * | 2016-08-15 | 2016-12-21 | 上海交通大学 | Multi-port modular multi-level converter for Multi-end flexible direct current transmission application |
| US20170054294A1 (en) * | 2015-08-18 | 2017-02-23 | Virginia Tech Intellectual Properties, Inc. | Modular multilevel converter capacitor voltage ripple reduction |
| CN107517007A (en) * | 2017-10-18 | 2017-12-26 | 西安交通大学 | A kind of nearly square-wave frequency modulation method of MMC type HVDC converter |
-
2018
- 2018-07-25 CN CN201810827102.9A patent/CN109038693A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103036451A (en) * | 2013-01-16 | 2013-04-10 | 广东电网公司电力科学研究院 | Electronic power transformer |
| JP2016063688A (en) * | 2014-09-19 | 2016-04-25 | 株式会社東芝 | Power conversion device |
| CN204131408U (en) * | 2014-09-24 | 2015-01-28 | 华中科技大学 | A kind of MMC type commutator transformer based on multi winding transformer coupling |
| US20170054294A1 (en) * | 2015-08-18 | 2017-02-23 | Virginia Tech Intellectual Properties, Inc. | Modular multilevel converter capacitor voltage ripple reduction |
| CN105896585A (en) * | 2016-04-28 | 2016-08-24 | 南方电网科学研究院有限责任公司 | AC side fault ride-through control method for hybrid multi-terminal DC power transmission system |
| CN106253728A (en) * | 2016-08-15 | 2016-12-21 | 上海交通大学 | Multi-port modular multi-level converter for Multi-end flexible direct current transmission application |
| CN106230269A (en) * | 2016-09-20 | 2016-12-14 | 西安交通大学 | A kind of dcdc converter modulator approach based on MMC |
| CN107517007A (en) * | 2017-10-18 | 2017-12-26 | 西安交通大学 | A kind of nearly square-wave frequency modulation method of MMC type HVDC converter |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103516230B (en) | Many level that bi-directional current controls balance solid-state transformer and its implementation mutually | |
| CN103197241B (en) | Flexible DC power transmission MMC converter valve operating test device and test method | |
| WO2012174827A1 (en) | Physical real-time dynamic simulation device for flexible direct-current transmission system | |
| CN106602885B (en) | Modularization multi-level converter four-quadrant frequency converter | |
| CN102158101A (en) | H-bridge cascaded multilevel voltage sag generator based on insulated gate bipolar transistor (IGBT) | |
| CN109067218A (en) | A kind of solid-state transformer topological structure method based on more level submodules | |
| CN106452133A (en) | Core converter for building bipolar DC microgrid and control method of core converter | |
| CN106341044A (en) | Comprehensive efficiency optimization control method for modularized power electronic transformer | |
| CN105656330A (en) | Capacitance voltage balancing strategy suitable for high level modular multilevel converter | |
| CN109980948A (en) | A kind of five port electric power electric transformer of three Coupling Between Phases | |
| CN110350797A (en) | A kind of very bipolar mesolow transformer topology and its control strategy based on TAB | |
| CN104065279A (en) | Voltage disturbance generation device and method for simulating power grid disturbance | |
| CN111177932B (en) | Modeling method for improving electromagnetic transient simulation speed of flexible substation | |
| CN109586590A (en) | Multi purpose space vector modulation method for current source type converter | |
| CN203491898U (en) | Bidirectional tide-controlled modularized multi-level mutually-balanced solid-state transformer | |
| CN111291468B (en) | Flexible substation modeling method for efficient electromagnetic transient simulation | |
| CN107800299A (en) | Modularized dc transformation system and its control method based on MMC high frequency conversions | |
| CN103337962A (en) | Offshore wind plant DC converge used three-level converter and control method thereof | |
| CN109510492A (en) | A kind of dual output MMC topology based on bridge arm bifurcation structure | |
| CN102820666B (en) | Three-phase power electronic transformer capable of balancing asymmetric load | |
| CN104184356B (en) | A kind of power model group of three-phase power electronic transformer | |
| CN109474193A (en) | A kind of modular solid-state transformer based on three level of diode clamp bit-type | |
| CN107134780A (en) | A kind of flexible multimode switch topology in port of Modularized medium-voltage three | |
| CN109038693A (en) | A kind of power distribution network based on MMC structure multiterminal no-load voltage ratio adjustable DC transformer topology and its control method | |
| CN208890652U (en) | A kind of new energy interface system based on double active bridge dcdc converters |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20181218 |
|
| RJ01 | Rejection of invention patent application after publication |