CN112583268A - Modular multilevel DC converter - Google Patents
Modular multilevel DC converter Download PDFInfo
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- CN112583268A CN112583268A CN202011516774.1A CN202011516774A CN112583268A CN 112583268 A CN112583268 A CN 112583268A CN 202011516774 A CN202011516774 A CN 202011516774A CN 112583268 A CN112583268 A CN 112583268A
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- chain
- chain type
- booster circuit
- type booster
- input end
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
A modular multilevel dc converter comprising: the chain type boosting module assembly is respectively connected with the low-voltage side capacitor and the high-voltage side capacitor of the direct-current bus through the inductance assembly; the chain type boosting module component adopts four boosting circuits which are connected in parallel in a staggered mode: the method specifically comprises the following steps: first chain boost circuit, second chain boost circuit, third chain boost circuit and fourth chain boost circuit, wherein: the first chain type booster circuit is arranged between the input end and the output end, the second chain type booster circuit is arranged between the input end and the negative electrode, the third chain type booster circuit is arranged between the input end and the output end, and the fourth chain type booster circuit is arranged between the input end and the negative electrode. The invention can realize larger step-up conversion ratio without using a transformer, has high reliability in the electric energy transmission process and small voltage loss, and has the advantages of modularization, expandability and simplicity.
Description
Technical Field
The invention relates to a technology in the field of direct current power supply and distribution, in particular to a modular multilevel direct current converter.
Background
A high-voltage alternating-current power transmission system is usually used in a traditional offshore wind farm, so that the economic cost is low, the structure of the power transmission system is simple, and the technical reliability is high. However, if the capacity of a large wind farm is large and the transmission distance is long, the high voltage ac transmission has disadvantages in terms of power loss and system stability.
There are many advantages to using a dc high voltage transmission system over conventional high voltage ac transmission. The whole process from power generation to grid connection avoids multiple times of rectification, inversion and boosting, and simultaneously, a heavy power frequency alternating current transformer is not needed. Therefore, the offshore direct current wind power station is superior to the existing offshore alternating current wind power station in the aspects of the size, the weight, the power loss, the construction economic cost and the like of equipment. High voltage direct current transmission systems based on Modular Multilevel Converters (MMC) have attracted extensive attention in the application of large-scale offshore wind farms due to the advantages of modular design, easy expansion of voltage and power, low harmonic distortion, and the like.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a modular multilevel DC converter which is composed of a boosting module, a low-voltage side inductor and a high-voltage measuring capacitor which are connected in series in a plurality of bridge type sub-module structures, can realize a larger boosting conversion ratio under the condition of not using a transformer, and has the advantages of high reliability in the electric energy transmission process, small voltage loss, modularization, expandability and simplicity.
The invention is realized by the following technical scheme:
the invention comprises the following steps: the method comprises the following steps: chain boost module subassembly, inductance component and high-pressure side electric capacity, wherein: the chain type boosting module assembly is respectively connected with the direct current bus low-voltage side capacitor and the direct current bus high-voltage side capacitor through the inductance assembly.
The chain type boosting module component adopts four boosting circuits which are connected in parallel in a staggered mode: the method specifically comprises the following steps: first chain boost circuit, second chain boost circuit, third chain boost circuit and fourth chain boost circuit, wherein: the first chain type booster circuit is arranged between the input end and the output end, the second chain type booster circuit is arranged between the input end and the negative electrode, the third chain type booster circuit is arranged between the input end and the output end, and the fourth chain type booster circuit is arranged between the input end and the negative electrode.
The inductance assembly comprises: the first low-voltage side inductor is arranged between the input end and the first chain type booster circuit, the second low-voltage side inductor is arranged between the input end and the third chain type booster circuit, the third resonant inductor is arranged between the first chain type booster circuit and the output end, and the fourth resonant inductor is arranged between the third chain type booster circuit and the output end.
The inductance value of the first low-voltage side inductor is equal to the inductance value of the second low-voltage side inductor.
And the inductance values of the third resonant inductor and the fourth resonant inductor are equal.
And a plurality of bridge structures connected in series are arranged in each chain type boosting module assembly.
The bridge structures in the first chain type booster circuit and the third chain type booster circuit are diode clamping type half-bridge structures, half-bridge structures or full-bridge structures.
And the bridge structures in the second chain type booster circuit and the fourth chain type booster circuit are half-bridge structures or full-bridge structures.
Technical effects
The invention integrally solves the problems that the existing offshore wind farm usually uses a transformer with large floor area and high price and a high-voltage AC/DC converter with unnecessary bidirectional power circulation capability, and increases the construction cost.
Compared with the prior art, the invention adopts a power balance control strategy, can realize the equal division of the inductive currents of two low-voltage sides while having higher boost ratio under the condition of not using an alternating-current transformer, increases and decreases the number of sub-modules according to the voltage level, and has the characteristics of modularization, expandability, wide input and output voltage application range and the like.
Drawings
FIG. 1 is a schematic diagram of a prior art interleaved boost converter topology;
FIG. 2 is a schematic of the topology of the present invention;
FIG. 3 is a schematic diagram of a bridge configuration according to the present invention;
in the figure: the high-voltage-side-switching-type direct-current bus comprises a first chain type booster circuit 1, a second chain type booster circuit 2, a third chain type booster circuit 3, a fourth chain type booster circuit 4, a first low-voltage-side inductor 5, a second low-voltage-side inductor 6, a third resonant inductor 7, a fourth resonant inductor 8, a high-voltage-side capacitor 9, a half-bridge structure 10, a full-bridge structure 11, a diode clamping half-bridge structure 12 and a direct-current bus low-voltage side 13.
Detailed Description
As shown in fig. 2, the present embodiment relates to a modular multilevel dc converter including: chain boost module subassembly, inductance component and high-pressure side electric capacity 9, wherein: the chain type boosting module assembly is respectively connected with the low-voltage side 13 and the high-voltage side capacitor 9 of the direct-current bus through the inductance assembly.
Chain boost module subassembly for adopting four boost circuit of crisscross parallel, specifically include: first chain boost circuit 1, second chain boost circuit 2, third chain boost circuit 3 and fourth chain boost circuit 4, wherein: the first chain type booster circuit 1 is arranged at the input end ULPositive pole and output terminal UHBetween the positive poles, the second chain type booster circuit 2 is arranged at the input end ULBetween the positive and negative poles of the third chain booster circuit 3 is arranged at the input end ULPositive pole and output terminal UHBetween the positive poles, a fourth chain booster circuit 4 is arranged at the input end ULBetween the positive electrode and the negative electrode.
The output end UHA high-voltage side capacitor 9 is further arranged between the anode and the cathode.
The inductance assembly comprises: is arranged at the input end ULA first low-voltage side inductor 5 arranged between the anode and the first chain type booster circuit 1 and arranged at the input end ULA second low-voltage side inductor 6 arranged between the anode of the first chain type booster circuit 1 and the third chain type booster circuit 3 and an output end UHAnd a third resonant inductor 7 arranged between the positive poles of the third chain booster circuit 3 and the output terminal UHBetween the positive poles of the first and second resonant inductors 8.
The inductance of the first low-voltage side inductor 5 is equal to the inductance of the second low-voltage side inductor 6.
As shown in fig. 3, the first and third chain booster circuits 1 and 3 are both composed of a plurality of bridge structures connected in series, and the bridge structures are a half-bridge structure 10, a full-bridge structure 11 or a diode-clamped half-bridge structure 12.
The second and fourth chain type booster circuits 2 and 4 are both composed of a plurality of bridge structures connected in series, and the bridge structures are half-bridge structures 10 or full-bridge structures 11.
Through specific practical experiments, the current ripple of the inductor L1 is 1.2A, the current ripple of the inductor L1 is 1.2A, and the current i ripple is 0.6A. The interleaving of the currents of the inductors L1 and L2 reduces the ripple of the input side current and realizes the current sharing between two phases. The input voltage is 20V, the input current is about 9.8A, and the total voltage is 196W; the output voltage is basically stabilized at about 200V by adopting double closed-loop control, the output current is 890mA, and the total output current is 178W. Obviously, the topology realizes 10 times of boost ratio, the conversion efficiency under the low-power working condition is about 90.8%, and the theoretical value of full-scale operation can reach more than 94%.
In conclusion, the modular multilevel DC converter provided by the invention realizes the application in the field of offshore wind power high-voltage DC. The high-frequency alternating current link and the transformer are not needed, and the high voltage boosting ratio is also achieved. The cost is reduced, and the volume of the converter is reduced.
The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (4)
1. A modular multilevel dc converter, comprising: chain boost module subassembly, inductance component and high-pressure side electric capacity, wherein: the chain type boosting module assembly is respectively connected with the low-voltage side capacitor and the high-voltage side capacitor of the direct-current bus through the inductance assembly;
the chain type boosting module component adopts four boosting circuits which are connected in parallel in a staggered mode: the method specifically comprises the following steps: first chain boost circuit, second chain boost circuit, third chain boost circuit and fourth chain boost circuit, wherein: the first chain type booster circuit is arranged between the input end and the output end, the second chain type booster circuit is arranged between the input end and the negative electrode, the third chain type booster circuit is arranged between the input end and the output end, and the fourth chain type booster circuit is arranged between the input end and the negative electrode;
the inductance assembly comprises: the first low-voltage side inductor is arranged between the input end and the first chain type booster circuit, the second low-voltage side inductor is arranged between the input end and the third chain type booster circuit, the third resonant inductor is arranged between the first chain type booster circuit and the output end, and the fourth resonant inductor is arranged between the third chain type booster circuit and the output end.
2. The modular multilevel dc-to-dc converter of claim 1 wherein the first low side inductor has an inductance value equal to the inductance value of the second low side inductor.
3. The modular multilevel dc-to-dc converter of claim 1, wherein the third resonant inductor and the fourth resonant inductor have equal inductance values.
4. The modular multilevel converter according to claim 1, wherein the first and third chain boost circuits are each formed by a plurality of bridge structures connected in series, and the bridge structures are half-bridge structures, full-bridge structures or diode-clamped half-bridge structures;
and the second chain type booster circuit and the fourth chain type booster circuit are both formed by a plurality of bridge structures connected in series, and the bridge structures are half-bridge structures or full-bridge structures.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011516774.1A CN112583268A (en) | 2020-12-21 | 2020-12-21 | Modular multilevel DC converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011516774.1A CN112583268A (en) | 2020-12-21 | 2020-12-21 | Modular multilevel DC converter |
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| CN112583268A true CN112583268A (en) | 2021-03-30 |
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| CN202011516774.1A Pending CN112583268A (en) | 2020-12-21 | 2020-12-21 | Modular multilevel DC converter |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5861734A (en) * | 1997-10-14 | 1999-01-19 | Lucent Technologies, Inc. | Control architecture for interleaved converters |
| CN103078544A (en) * | 2013-01-31 | 2013-05-01 | 苏州欧姆尼克新能源科技有限公司 | Direct current/alternating current converting system |
| CN107257206A (en) * | 2017-05-15 | 2017-10-17 | 上海交通大学 | A kind of three end commutator transformers |
| CN107425713A (en) * | 2017-08-24 | 2017-12-01 | 上海交通大学 | A kind of Autotransformer DC converter and its control method |
-
2020
- 2020-12-21 CN CN202011516774.1A patent/CN112583268A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5861734A (en) * | 1997-10-14 | 1999-01-19 | Lucent Technologies, Inc. | Control architecture for interleaved converters |
| CN103078544A (en) * | 2013-01-31 | 2013-05-01 | 苏州欧姆尼克新能源科技有限公司 | Direct current/alternating current converting system |
| CN107257206A (en) * | 2017-05-15 | 2017-10-17 | 上海交通大学 | A kind of three end commutator transformers |
| CN107425713A (en) * | 2017-08-24 | 2017-12-01 | 上海交通大学 | A kind of Autotransformer DC converter and its control method |
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Application publication date: 20210330 |
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