CN110611435A - A Cascaded Flexible AC Link Converter Topology - Google Patents
A Cascaded Flexible AC Link Converter Topology Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for AC mains or AC distribution networks
- H02J3/36—Arrangements for transfer of electric power between AC networks via a high-tension DC link
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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
- 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
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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
- 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
- H02M5/22—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 discharge tubes with control electrode or semiconductor devices with control electrode
- H02M5/275—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 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
- H02M5/293—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 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
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
- H02M1/007—Plural converter units in cascade
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Ac-Ac Conversion (AREA)
Abstract
本发明公开了一种级联型灵活交流链变换器拓扑结构，包括三相交流电源、3个功率调节单元、3个Buck型直接式AC‑AC变换器UT‑AC、三相多绕组隔离变压器、3个LC低通滤波器；其中，每个功率调节单元由两个双极性直接式AC‑AC变换器BT‑AC组成。本发明的拓扑结构能够控制互联馈线之间的潮流，实现配电网馈线的柔性互联故障情况下，可以实现对于隔离负载的恢复供电；通过对配电网中馈线的柔性互联，能够提高分布式发电在配电网中的渗透率，提高配电网的电能质量和供电可靠性。
The invention discloses a topological structure of a cascaded flexible AC link converter, including a three-phase AC power supply, three power adjustment units, three Buck-type direct AC-AC converters UT-AC, and a three-phase multi-winding isolation transformer , 3 LC low-pass filters; wherein, each power adjustment unit is composed of two bipolar direct AC-AC converters BT-AC. The topology structure of the present invention can control the power flow between the interconnected feeders, and realize the flexible interconnection of the distribution network feeder. In the case of a failure, the recovery power supply for the isolated load can be realized; through the flexible interconnection of the feeder lines in the distribution network, the distributed The penetration rate of power generation in the distribution network improves the power quality and power supply reliability of the distribution network.
Description
技术领域technical field
本发明属于配电网柔性互联技术领域，具体涉及一种级联型灵活交流链变换器拓扑结构。The invention belongs to the technical field of flexible interconnection of distribution networks, and in particular relates to a topology structure of a cascaded flexible AC link converter.
背景技术Background technique
分布式可再生能源发电并网容量的急剧增大，以电动汽车为代表的新型负荷的大规模接入，电源结构与种类的不断变化，负荷特性的日益多样化，已经对当前的配电网产生了广泛而深远的影响。主要表现为：功率流向日趋复杂，负荷波动加剧，单电源辐射状结构变成有源网络结构，电压越限等电能质量问题日益突出，供电可靠性降低。以光伏与风电为代表的可再生能源发电具有典型的间歇性、随机性，其发电出力随时间尺度和地理范围的变化率相对较高，同一条馈线上可再生能源出力与负荷的时序特性决定了可再生能源高出力时段与重负荷时段的错位，这对配电网的电能质量和可再生能源消纳均产生不利的影响。此外，配电网的运行也面临着电磁环网的解环与合环、提高负载率的均衡度、无功电压的优化控制以及避免短时供电中断等问题。围绕这些问题，国内外的研究者提出了实时重构、主动配电网分层分布式控制以及需求侧响应等多种解决方案。然而，配电网的柔性互联是实现上述解决方案的重要基础，传统的互联方式缺乏足够的可控性和灵活性。当前配电网的联络通常依靠分段和联络开关以及变压器分接头。分段和联络开关仅仅有开、合两种状态，响应速度一般为秒级，开合动作次数也有明确的限制，不具备调节能力并且会增大短路电流。配电变压器增加分接头是一种具备调节能力的方案，但是采用分接头调节灵活度有限，并且调节范围比较窄、调节精度也比较低。因此目前配电网的这些传统装备，已经不能满足当前配电网对智能化、精细化以及实时化的运行要求。The sharp increase in the grid-connected capacity of distributed renewable energy power generation, the large-scale access of new loads represented by electric vehicles, the constant changes in the structure and types of power sources, and the increasing diversification of load characteristics have already affected the current distribution network. had a wide-ranging and far-reaching impact. The main manifestations are: the power flow direction is becoming more and more complicated, the load fluctuation is intensified, the radial structure of single power supply becomes an active network structure, the power quality problems such as voltage limit are becoming more and more prominent, and the reliability of power supply is reduced. Renewable energy power generation represented by photovoltaic and wind power is typically intermittent and random, and its power generation output has a relatively high rate of change with time scales and geographical scope. The timing characteristics of renewable energy output and load on the same feeder determine The dislocation between the high output period and the heavy load period of renewable energy has a negative impact on the power quality of the distribution network and the consumption of renewable energy. In addition, the operation of the distribution network is also faced with problems such as unwinding and closing of the electromagnetic ring network, improving the balance of the load rate, optimizing the control of reactive power and voltage, and avoiding short-term power supply interruptions. Around these problems, researchers at home and abroad have proposed various solutions such as real-time reconstruction, hierarchical distributed control of active distribution network, and demand-side response. However, the flexible interconnection of the distribution network is an important basis for realizing the above solutions, and the traditional interconnection method lacks sufficient controllability and flexibility. The connection of the current distribution network usually relies on section and tie switches and transformer taps. Sectional and contact switches only have two states of opening and closing, the response speed is generally in the second level, and the number of opening and closing actions is also clearly limited. They do not have the ability to adjust and will increase the short-circuit current. Adding taps to distribution transformers is a solution with adjustment capabilities, but the adjustment flexibility of taps is limited, and the adjustment range is relatively narrow and the adjustment accuracy is relatively low. Therefore, these traditional equipment of the current distribution network can no longer meet the requirements of the current distribution network for intelligent, refined and real-time operation.
随着电力电子变换技术的快速发展，基于电力电子技术的配电网柔性互联装备受到广泛的关注和研究，与传统的联络开关相比，基于电力电子技术的柔性互联装备，不仅具备开和合两种状态，而且不存在机械式开关动作次数的限制，增加了功率连续可控状态，兼具运行柔性切换、控制方式灵活多样等特点。引起关注最终多的是柔性直流输电系统，2003年前后，研究者就考虑是否可以将VSC-HVDC用于城市配电网，但是由于必须采用IGBT串联型换流器，其研制难度大，造价昂贵、损耗较高，因此相关研究仅仅停留在了概念层面。英国帝国理工大学提出了软常开点(Soft Normally-Open Point,SNOP)的概念，SNOP能够准确的控制其所连接两侧馈线的有功与无功功率，改变了传统配电网闭环设计、开环运行的供电方式，提高了配电网的供电可靠性，改善了负载率的均衡度。目前基于模块化多电平换流器(MMC)拓扑结构的SNOP装备成为主流技术，MMC因其能够模块化生产的优点，已在国内外多个工程中用于新能源并网或输电网分区互联。然而，MMC型VSC-HVDC存在的一些特点可能会不利于它在配电网中的应用。MMC采用了基于全控型器件(比如IGBT)的AC/DC/AC的两级功率变换，降低了变换器的效率，增加了直流侧故障保护的难度。此外，MMC拓扑结构中必须要使用大量的直流侧电容器，这会导致装备的体积过大、成本过高。基于MMC的SNOP装备拥有一个巨大的优势就是能够实现异步互联，然而在配电网中几乎对这方面没有需求。With the rapid development of power electronic conversion technology, flexible interconnection equipment for distribution networks based on power electronics technology has received extensive attention and research. Compared with traditional contact switches, flexible interconnection equipment based on power electronics technology not only has two state, and there is no limitation on the number of mechanical switching actions, which increases the continuous controllable state of power, and has the characteristics of flexible switching of operation and flexible and diverse control methods. At the end of the day, the flexible DC transmission system attracted the most attention. Around 2003, researchers considered whether VSC-HVDC could be used in urban power distribution networks. However, since IGBT series converters must be used, its development is difficult and expensive. , The loss is high, so the relevant research only stays at the conceptual level. Imperial College London proposed the concept of Soft Normally-Open Point (SNOP). SNOP can accurately control the active and reactive power of the feeders on both sides of its connection, which has changed the traditional closed-loop design and open-loop design of distribution network. The power supply mode of the ring operation improves the power supply reliability of the distribution network and improves the balance of the load rate. At present, SNOP equipment based on the modular multilevel converter (MMC) topology has become the mainstream technology. Because of the advantages of modular production, MMC has been used in new energy grid connection or transmission network partitioning in many projects at home and abroad. interconnected. However, some characteristics of MMC type VSC-HVDC may be unfavorable for its application in distribution network. MMC adopts AC/DC/AC two-stage power conversion based on fully controlled devices (such as IGBT), which reduces the efficiency of the converter and increases the difficulty of DC side fault protection. In addition, a large number of DC-side capacitors must be used in the MMC topology, which will lead to excessive equipment size and high cost. A huge advantage of MMC-based SNOP equipment is that it can realize asynchronous interconnection, but there is almost no demand for this aspect in the distribution network.
发明内容Contents of the invention
本发明的目的是提供一种级联型灵活交流链变换器拓扑结构，该拓扑能够控制互联馈线之间的潮流，实现配电网馈线的柔性互联。The purpose of the present invention is to provide a cascaded flexible AC link converter topology, which can control the power flow between interconnected feeders and realize the flexible interconnection of distribution network feeders.
本发明所采用的技术方案是，一种级联型灵活交流链变换器拓扑结构，包括三相交流电源、3个功率调节单元、3个Buck型直接式AC-AC变换器UT-AC、三相多绕组隔离变压器、3个LC低通滤波器；其中，每个功率调节单元由两个双极性直接式AC-AC变换器BT-AC组成；The technical solution adopted in the present invention is a cascaded flexible AC link converter topology, including a three-phase AC power supply, three power regulation units, three Buck-type direct AC-AC converters UT-AC, three Phase multi-winding isolation transformer, 3 LC low-pass filters; each power adjustment unit is composed of two bipolar direct AC-AC converters BT-AC;
一条馈线末端节点A、B、C三相交流电源接入三相多绕组隔离变压器的一次侧；三相多绕组隔离变压器的二次侧共9个绕组，每个单相3个绕组，每个单相的3个绕组分别对应为1个UT-AC、2个BT-AC供电；A相UT-AC变换器输出端口的负极与B相BT-AC变换器输出端口的正极相连；B相BT-AC变换器输出端口的负极与C相BT-AC变换器输出端口的正极相连；A相UT-AC变换器输出端口的正极与C相BT-AC变换器输出端口的负极构成输出二端口，输出二端口的正极连接于另一条馈线的末端，负极与其它两相输出二端口的负极连接于一点N2；A feeder end node A, B, C three-phase AC power supply is connected to the primary side of the three-phase multi-winding isolation transformer; the secondary side of the three-phase multi-winding isolation transformer has a total of 9 windings, each single-phase 3 windings, each The three single-phase windings respectively supply power for one UT-AC and two BT-ACs; the negative pole of the output port of the A-phase UT-AC converter is connected to the positive pole of the output port of the B-phase BT-AC converter; the B-phase BT - The negative pole of the output port of the AC converter is connected to the positive pole of the output port of the C-phase BT-AC converter; the positive pole of the output port of the A-phase UT-AC converter and the negative pole of the output port of the C-phase BT-AC converter constitute two output ports, The positive pole of the second output port is connected to the end of another feeder, and the negative pole is connected to the negative pole of the other two-phase output two ports at one point N2;
所述B、C相的接法同A相。The connection method of the B and C phases is the same as that of the A phase.
本发明的特点还在于：The present invention is also characterized in that:
A相的功率调节单元由两个双极性直接式AC-AC变换器BT-AC组成；B相变压器二次侧绕组Tb2为BT-AC变换器Ba的交流输入；C相变压器二次侧绕组Tc2为BT-AC变换器Ca的交流输入；变换器Ba输出二端口的负极与变换器Ca输出二端口的正极相连，构成应用于A相的功率变换单元；功率变换单元的输出为二端口，其正极为变换器Ba输出二端口的正极，负极为变换器Ca输出二端口的负极；The power regulation unit of phase A is composed of two bipolar direct AC-AC converters BT-AC; the secondary side winding Tb2 of the B-phase transformer is the AC input of the BT-AC converter Ba; the secondary side winding of the C-phase transformer Tc2 is the AC input of the BT-AC converter Ca; the negative pole of the two output ports of the converter Ba is connected to the positive pole of the two output ports of the converter Ca to form a power conversion unit applied to the A phase; the output of the power conversion unit is two ports, Its positive pole is the positive pole of the two output ports of the converter Ba, and its negative pole is the negative pole of the two output ports of the converter Ca;
B相的功率调节单元由两双极性直接式AC-AC变换器组成；A相变压器二次侧绕组Ta3为BT-AC变换器Ab的交流输入；C相变压器二次侧绕组Tc3为BT-AC变换器Cb的交流输入；变换器Ab输出二端口的负极与变换器Cb输出二端口的正极相连，构成应用于B相的功率变换单元；功率变换单元的输出为二端口，其正极为变换器Ab输出二端口的正极，负极为变换器Cb输出二端口的负极；The power regulation unit of phase B is composed of two bipolar direct AC-AC converters; the secondary side winding Ta3 of the phase A transformer is the AC input of the BT-AC converter Ab; the secondary side winding Tc3 of the phase C transformer is the AC input of the BT- The AC input of the AC converter Cb; the negative pole of the two output ports of the converter Ab is connected to the positive pole of the two output ports of the converter Cb to form a power conversion unit applied to the B phase; the output of the power conversion unit is two ports, and its positive pole is converted The positive pole of the two-port output of the converter Ab, and the negative pole of the two-port output of the converter Cb;
C相的功率调节单元由两个双极性直接式AC-AC变换器组成；A相变压器二次侧绕组Ta4为BT-AC变换器Ac的交流输入；B相变压器二次侧绕组Tb4为BT-AC变换器Bc的交流输入；变换器Ac输出二端口的负极与变换器Bc输出二端口的正极相连，构成应用于C相的功率变换单元；功率变换单元的输出为二端口，其正极为变换器Ac输出二端口的正极，负极为变换器Bc输出二端口的负极。The power regulation unit of phase C is composed of two bipolar direct AC-AC converters; the secondary side winding Ta4 of the phase A transformer is the AC input of the BT-AC converter Ac; the secondary winding Tb4 of the phase B transformer is the AC input of the BT - the AC input of the AC converter Bc; the negative pole of the two output ports of the converter Ac is connected to the positive pole of the two output ports of the converter Bc to form a power conversion unit applied to the C phase; the output of the power conversion unit is two ports, and its positive pole is The converter Ac outputs the positive pole of the two ports, and the negative pole outputs the negative pole of the two ports of the converter Bc.
双极性直接式AC-AC变换器BT-AC由输入滤波电容、H桥、信号控制单元组成；其中，H桥由正、负桥臂构成；The bipolar direct AC-AC converter BT-AC is composed of an input filter capacitor, an H-bridge, and a signal control unit; among them, the H-bridge is composed of positive and negative bridge arms;
输入滤波电容为高频薄膜电容；输入滤波电容一端与单相交流输入的正极连接，另一端与单相交流输入的负极连接；H桥的每个桥臂由4个全控型功率开关管、1个箝位电容构组成；正、负极性桥臂的一端与单相交流电源的正极连接，另一端与负极连接；正、负极性桥臂对地各有一个输出端口，两个桥臂构成二端输出端口。The input filter capacitor is a high-frequency film capacitor; one end of the input filter capacitor is connected to the positive pole of the single-phase AC input, and the other end is connected to the negative pole of the single-phase AC input; each bridge arm of the H-bridge consists of 4 fully-controlled power switch tubes, Composed of a clamping capacitor structure; one end of the positive and negative bridge arms is connected to the positive pole of the single-phase AC power supply, and the other end is connected to the negative pole; each of the positive and negative polarity bridge arms has an output port to the ground, and the two bridge arms constitute Two-terminal output port.
正极性桥臂的全控型功率开关管由上到下依次为S2、S1、S1c、S2c；S2的发射极与单相交流电源的正极连接，集电极与S1的集电极连接；S1的发射极与S1c的集电极连接，S1c的发射极与S2c的发射极连接；S2c的集电极与单相交流电源的负极连接；箝位电容C3一端与S1的集电极相连，另一端与S1c的发射极相连；正极性桥臂的输出端由开关管S1的发射极与S1c的集电极之间引出。The full-control power switch tubes of the positive bridge arm are S 2 , S 1 , S 1c , and S 2c from top to bottom; the emitter of S 2 is connected to the positive pole of the single-phase AC power supply, and the collector is connected to the collector of S 1 Electrode connection; the emitter of S 1 is connected to the collector of S 1c , the emitter of S 1c is connected to the emitter of S 2c ; the collector of S 2c is connected to the negative pole of the single-phase AC power supply; one end of clamping capacitor C 3 is connected to The collector of S 1 is connected, and the other end is connected with the emitter of S 1c ; the output end of the positive bridge arm is drawn between the emitter of switch S 1 and the collector of S 1c .
构成负极性桥臂的全控型功率开关管由上到下依次为S2p、S1p、S1cp、S2cp；S2p的发射极与单相交流电源的正极连接，集电极与S1p的集电极连接；S1p的发射极与S1cp的集电极连接；S1cp的发射极与S2cp的发射极连接；S2cp的集电极与单相交流电源的负极连接；箝位电容C2箝位在开关管S1p的集电极与S1cp的发射极之间引出。The fully-controlled power switch tubes that constitute the negative bridge arm are S 2p , S 1p , S 1cp , and S 2cp from top to bottom; the emitter of S 2p is connected to the positive pole of the single-phase AC power supply, and the collector is connected to the positive pole of S 1p The collector is connected; the emitter of S 1p is connected to the collector of S 1cp ; the emitter of S 1cp is connected to the emitter of S 2cp ; the collector of S 2cp is connected to the negative pole of the single-phase AC power supply; the clamp capacitor C 2 is clamped It is drawn between the collector of the switch tube S 1p and the emitter of S 1cp .
Buck型直接式AC-AC变换器UT-AC每相一个；Buck型直接式AC-AC变换器UT-AC由交流输入电源、两个输入电容、四个全控型功率开关管IGBT组成；电容C1的负极与电容C2的正极相连；电容C1的正极与电源的正极相连；电容C2的负极与电源的负极相连；四个IGBT从上到下依次为T1、T2、T3、T4；T1的集电极与C1的正极相连，发射极与T2的集电极连接；T2的发射极连接至T3的发射极；T3的集电极与T4的发射极连接；T4的集电极与电容C2的负极相连；C1的负极与T2的发射极连接；T1的发射极为桥臂的正极输出，T3的集电极为桥臂的负极输出，这两个端口构成Buck型直接式AC-AC变换器UT-AC的输出二端口。One Buck type direct AC-AC converter UT-AC for each phase; Buck type direct AC-AC converter UT-AC is composed of AC input power supply, two input capacitors, and four fully-controlled power switch tubes IGBT; The negative pole of C1 is connected to the positive pole of capacitor C2; the positive pole of capacitor C1 is connected to the positive pole of the power supply; the negative pole of capacitor C2 is connected to the negative pole of the power supply; the four IGBTs are T1, T2, T3, T4 from top to bottom; the set of T1 The electrode is connected to the positive pole of C1, and the emitter is connected to the collector of T2; the emitter of T2 is connected to the emitter of T3; the collector of T3 is connected to the emitter of T4; the collector of T4 is connected to the negative pole of capacitor C2; C1 The negative electrode of T1 is connected to the emitter of T2; the emitter of T1 is the positive output of the bridge arm, and the collector of T3 is the negative output of the bridge arm. These two ports constitute the output two of the Buck type direct AC-AC converter UT-AC port.
三相多绕组隔离变压器的A相输入绕组为Ta1，A相输出绕组为Ta2、Ta3、Ta4，变比为Ta1：Ta2：Ta3：Ta4＝2：2：1：1；B相输入绕组为Tb1，B相输出绕组为Tb2、Tb3、Tb4，变比为Tb1：Tb2：Tb3：Tb4＝2：2：1：1；C相输入绕组为Tc1，C相输出绕组为Tc2、Tc3、Tc4，变比为Tc1：Tc2：Tc3：Tc4＝2：2：1：1；变压器的所有绕组之间均隔离。The A-phase input winding of the three-phase multi-winding isolation transformer is Ta1, the A-phase output winding is Ta2, Ta3, Ta4, and the transformation ratio is Ta1:Ta2:Ta3:Ta4=2:2:1:1; the B-phase input winding is Tb1 , the B-phase output windings are Tb2, Tb3, Tb4, and the transformation ratio is Tb1:Tb2:Tb3:Tb4=2:2:1:1; the C-phase input winding is Tc1, and the C-phase output windings are Tc2, Tc3, Tc4. The ratio is Tc1: Tc2: Tc3: Tc4 = 2:2:1:1; all windings of the transformer are isolated from each other.
LC低通滤波器每相一个；LC低通滤波器由输出滤波电感、输出滤波电容组成；电感L与电容C组成二端口；LC低通滤波器的输入二端口与每相各模块级联后的输出二端口连接，输出端口即为各相电压出端口。One LC low-pass filter for each phase; LC low-pass filter is composed of output filter inductor and output filter capacitor; inductance L and capacitor C form two ports; the input two ports of LC low-pass filter are cascaded with each module of each phase The two output ports are connected, and the output port is the output port of each phase voltage.
一条馈线末端节点A、B、C三相交流电源分别对应接入三相多绕组隔离变压器的输入绕组Ta1、Tb1、Tc1；A相接绕组Ta1的正极，B相接绕组Tb1的正极，C相接绕组Tc1的正极；绕组Ta1、Tb1、Tc1的负极连接在一起，连接点为N1；A相变压器的二次侧绕组Ta2接Buck型直接式AC-AC变换器Aa的输入端，绕组Ta3接BT-AC变换器Ab的输入端，绕组Ta4接BT-AC变换器Ac的输入端；B相变压器的二次侧绕组Tb2接BT-AC变换器Ba的输入端，绕组Tb3接Buck型直接式AC-AC变换器Bb的输入端，绕组Tb4接BT-AC变换器Bc的输入端；C相变压器的二次侧绕组Tc2接BT-AC变换器Ca的输入端，绕组Tc3接BT-AC变换器Cb的输入端，绕组Tc4接Buck型直接式AC-AC变换器Cc的输入端；Aa变换器输出端口的负极接Ba变换器输出端口的正极，Ba变换器输出端口的负极极与Ca变换器输出端口的正极相连；Ab变换器输出端口的负极接Bb变换器输出端口的正极，Bb变换器输出端口的负极极与Cb变换器输出端口的正极相连；Ac变换器输出端口的负极接Bc变换器输出端口的正极，Bc变换器输出端口的负极极与Cc变换器输出端口的正极相连；Ca变换器输出端口的负极、Cb变换器输出端口的负极、Cc变换器输出端口的负极连在一起，连接点为N2；Aa、Ba、Ca共用一个LC滤波器；Ab、Bb、Cb共用一个LC滤波器；Ac、Bc、Cc共用一个LC滤波器；各相滤波器的输入二端口与各自相所有模块级联后的输出二端口连接；Aa变换器输出端口的正极、Ab变换器输出端口的正极、Ac变换器输出端口的正极分别对应为A、B、C三相电压输出，且均连接于另一条馈线的末端。The three-phase AC power supply at the end nodes A, B, and C of a feeder is respectively connected to the input windings Ta1, Tb1, and Tc1 of the three-phase multi-winding isolation transformer; phase A is connected to the positive pole of winding Ta1, phase B is connected to the positive pole of winding Tb1, and phase C connected to the positive pole of winding Tc1; the negative poles of windings Ta1, Tb1, and Tc1 are connected together, and the connection point is N1; the secondary side winding Ta2 of the A-phase transformer is connected to the input end of Buck type direct AC-AC converter Aa, and winding Ta3 is connected to The input end of the BT-AC converter Ab, the winding Ta4 is connected to the input end of the BT-AC converter Ac; the secondary side winding Tb2 of the B-phase transformer is connected to the input end of the BT-AC converter Ba, and the winding Tb3 is connected to the Buck type direct type The input terminal of the AC-AC converter Bb, the winding Tb4 is connected to the input terminal of the BT-AC converter Bc; the secondary side winding Tc2 of the C-phase transformer is connected to the input terminal of the BT-AC converter Ca, and the winding Tc3 is connected to the BT-AC converter The input end of the converter Cb, the winding Tc4 is connected to the input end of the Buck type direct AC-AC converter Cc; the negative pole of the output port of the Aa converter is connected to the positive pole of the output port of the Ba converter, and the negative pole of the output port of the Ba converter is transformed with Ca connected to the positive pole of the output port of the converter; the negative pole of the output port of the Ab converter is connected to the positive pole of the output port of the Bb converter, and the negative pole of the output port of the Bb converter is connected to the positive pole of the output port of the Cb converter; The positive pole of the output port of the converter, the negative pole of the output port of the Bc converter are connected to the positive pole of the output port of the Cc converter; the negative pole of the output port of the Ca converter, the negative pole of the output port of the Cb converter, and the negative pole of the output port of the Cc converter are connected to Together, the connection point is N2; Aa, Ba, Ca share one LC filter; Ab, Bb, Cb share one LC filter; Ac, Bc, Cc share one LC filter; the input two ports of each phase filter are connected to their respective After cascading all modules of each phase, the two output ports are connected; the positive pole of the output port of the Aa converter, the positive pole of the output port of the Ab converter, and the positive pole of the output port of the Ac converter correspond to the three-phase voltage output of A, B, and C respectively, and all Connect to the end of another feeder.
本发明的有益效果是：The beneficial effects of the present invention are:
(1)与传统AC-AC变换器拓扑结构相比，本结构所采用的BT-AC变换器无需有损耗的RC缓冲电路，也不需要采用专门的换流策略就能够实现安全换流，提高了变换器的可靠性；(1) Compared with the traditional AC-AC converter topology, the BT-AC converter adopted in this structure does not need a lossy RC snubber circuit, nor does it need to adopt a special commutation strategy to achieve safe commutation, improving Improve the reliability of the converter;
(2)本发明的功率变换单元无论是是输出什么角度和幅值的电压，都工作在buck/boost模式，除了闭锁模式外，输出电流不会出现断续；同时输出电压范围广，其相角范围为360度，幅值范围随变压器变比任意可调；(2) The power conversion unit of the present invention works in the buck/boost mode no matter what angle and amplitude voltage it outputs, and the output current will not be intermittent except in the blocking mode; at the same time, the output voltage range is wide, and its phase The angle range is 360 degrees, and the amplitude range can be adjusted arbitrarily with the transformer ratio;
(3)与采用SSSC的SOP相比，本发明可连续灵活的调节馈线之间的有功和无功功率，并且功率调节范围可随着变压器的改变而提高；除此之外在一定范围内有功功率和无功功率的调节是解耦的，可实现有功功率和无功功率的独立控制；(3) Compared with the SOP using SSSC, the present invention can continuously and flexibly adjust the active and reactive power between the feeders, and the power adjustment range can be improved with the change of the transformer; in addition, the active power within a certain range The adjustment of power and reactive power is decoupled, which can realize the independent control of active power and reactive power;
(4)在发生故障时，可利用Buck型直接式AC-AC变换器将两条馈线断开，实现对电网和负载的保护，还可对负载提供不间断供电；(4) In the event of a fault, the Buck type direct AC-AC converter can be used to disconnect the two feeders to protect the power grid and the load and provide uninterrupted power supply to the load;
(5)与其他类型的SOP相比，本发明没有直流环节，也没有储能设备，不需要对电能进行多次变换，拥有更好的稳定性，提高了装置的效率和可靠性，有效的减小了装置的体积和成本；(5) Compared with other types of SOP, the present invention has no direct current link and no energy storage equipment, does not need to convert electric energy multiple times, has better stability, improves the efficiency and reliability of the device, and effectively Reduced size and cost of the device;
(6)本发明的拓扑结构能够控制互联馈线之间的潮流，实现配电网馈线的柔性互联故障情况下，可以实现对于隔离负载的恢复供电；通过对配电网中馈线的柔性互联，能够提高分布式发电在配电网中的渗透率，提高配电网的电能质量和供电可靠性。(6) The topological structure of the present invention can control the power flow between the interconnected feeders, and realize the flexible interconnection of the distribution network feeder. In the case of a fault, the recovery power supply for the isolated load can be realized; Improve the penetration rate of distributed power generation in the distribution network, and improve the power quality and power supply reliability of the distribution network.
附图说明Description of drawings
图1是本发明变换器拓扑结构的电性连接示意图；Fig. 1 is the electrical connection schematic diagram of converter topological structure of the present invention;
图2是本发明变换器拓扑结构在馈线中的连接示意图；Fig. 2 is a schematic diagram of the connection of the converter topology in the feeder of the present invention;
图3是本发明变换器拓扑结构中功率调节单元的电性连接示意图；Fig. 3 is a schematic diagram of the electrical connection of the power regulation unit in the converter topology of the present invention;
图4是本发明变换器拓扑结构中BT-AC变换器的拓扑结构图；Fig. 4 is the topological structure diagram of the BT-AC converter in the converter topological structure of the present invention;
图5是本发明变换器拓扑结构中BT-AC变换器的控制原理图；Fig. 5 is the control schematic diagram of the BT-AC converter in the converter topology of the present invention;
图6是本发明变换器拓扑结构中UT-AC变换器的拓扑结构图；Fig. 6 is the topology structure diagram of the UT-AC converter in the converter topology structure of the present invention;
图7是本发明变换器拓扑结构的电压调节原理图；Fig. 7 is a schematic diagram of the voltage regulation of the converter topology of the present invention;
图8是本发明变换器拓扑结构中变压器变比为1：1：1：1时的电压补偿范围图；Fig. 8 is a voltage compensation range diagram when the transformer transformation ratio is 1:1:1:1 in the converter topology of the present invention;
图9是本发明变换器拓扑结构中LC低通滤波器原理图；Fig. 9 is a schematic diagram of the LC low-pass filter in the converter topology of the present invention;
图10是本发明变换器拓扑结构的调幅值模式输出正极性补偿电压波形图；Fig. 10 is a waveform diagram of the positive polarity compensation voltage output in the amplitude modulation value mode of the converter topology of the present invention;
图11是本发明变换器拓扑结构的调幅值模式输出负极性补偿电压波形图；Fig. 11 is a waveform diagram of negative polarity compensation voltage output in the amplitude modulation value mode of the converter topology of the present invention;
图12是本发明变换器拓扑结构的调相位模式滞后补偿输出电压波形图；Fig. 12 is a waveform diagram of the lag compensation output voltage in the phase modulation mode of the converter topology of the present invention;
图13是本发明变换器拓扑结构的调相位模式超前补偿输出电压波形图；Fig. 13 is a waveform diagram of the phase modulation mode lead compensation output voltage of the converter topology of the present invention;
图14是本发明变换器拓扑结构的移相调压模式输出电压波形图；Fig. 14 is a waveform diagram of the output voltage in the phase-shift voltage regulation mode of the converter topology of the present invention;
图15是本发明变换器拓扑结构的带阻性负载时的输出波形图。Fig. 15 is an output waveform diagram of the converter topology of the present invention with a resistive load.
具体实施方式Detailed ways
下面结合附图和具体实施方式对本发明进行详细说明。The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.
如图1、图2所示，本发明一种级联型灵活交流链变换器拓扑结构，包括三相交流电源、3个功率调节单元、3个Buck型直接式AC-AC变换器UT-AC、三相多绕组隔离变压器、3个LC低通滤波器；其中，每个功率调节单元由两个双极性直接式AC-AC变换器BT-AC组成；As shown in Figure 1 and Figure 2, a cascaded flexible AC link converter topology of the present invention includes a three-phase AC power supply, 3 power regulation units, and 3 Buck-type direct AC-AC converters UT-AC , three-phase multi-winding isolation transformer, three LC low-pass filters; wherein, each power adjustment unit is composed of two bipolar direct AC-AC converters BT-AC;
一条馈线末端节点A、B、C三相交流电源接入三相多绕组隔离变压器的一次侧；三相多绕组隔离变压器的二次侧共9个绕组，每个单相3个绕组，每个单相的3个绕组分别对应为1个UT-AC、2个BT-AC供电；A相UT-AC变换器输出端口的负极与B相BT-AC变换器输出端口的正极相连；B相BT-AC变换器输出端口的负极与C相BT-AC变换器输出端口的正极相连；A相UT-AC变换器输出端口的正极与C相BT-AC变换器输出端口的负极构成输出二端口，输出二端口的正极连接于另一条馈线的末端，负极与其它两相输出二端口的负极连接于一点N2；A feeder end node A, B, C three-phase AC power supply is connected to the primary side of the three-phase multi-winding isolation transformer; the secondary side of the three-phase multi-winding isolation transformer has a total of 9 windings, each single-phase 3 windings, each The three single-phase windings respectively supply power for one UT-AC and two BT-ACs; the negative pole of the output port of the A-phase UT-AC converter is connected to the positive pole of the output port of the B-phase BT-AC converter; the B-phase BT - The negative pole of the output port of the AC converter is connected to the positive pole of the output port of the C-phase BT-AC converter; the positive pole of the output port of the A-phase UT-AC converter and the negative pole of the output port of the C-phase BT-AC converter constitute two output ports, The positive pole of the second output port is connected to the end of another feeder, and the negative pole is connected to the negative pole of the other two-phase output two ports at one point N2;
B、C相的接法同A相。The connection method of phase B and phase C is the same as that of phase A.
如图3所示，A相的功率调节单元由两个双极性直接式AC-AC变换器BT-AC组成；B相变压器二次侧绕组Tb2为BT-AC变换器Ba的交流输入；C相变压器二次侧绕组Tc2为BT-AC变换器Ca的交流输入；变换器Ba输出二端口的负极与变换器Ca输出二端口的正极相连，构成应用于A相的功率变换单元；功率变换单元的输出为二端口，其正极为变换器Ba输出二端口的正极，负极为变换器Ca输出二端口的负极；As shown in Figure 3, the power regulation unit of phase A is composed of two bipolar direct AC-AC converters BT-AC; the secondary side winding Tb2 of the phase B transformer is the AC input of the BT-AC converter Ba; C The secondary side winding Tc2 of the phase transformer is the AC input of the BT-AC converter Ca; the negative pole of the two output ports of the converter Ba is connected to the positive pole of the two output ports of the converter Ca, forming a power conversion unit applied to the A phase; the power conversion unit The output of is two ports, its positive pole is the positive pole of converter Ba outputting two ports, and the negative pole is the negative pole of converter Ca outputting two ports;
B相的功率调节单元由两双极性直接式AC-AC变换器组成；A相变压器二次侧绕组Ta3为BT-AC变换器Ab的交流输入；C相变压器二次侧绕组Tc3为BT-AC变换器Cb的交流输入；变换器Ab输出二端口的负极与变换器Cb输出二端口的正极相连，构成应用于B相的功率变换单元；功率变换单元的输出为二端口，其正极为变换器Ab输出二端口的正极，负极为变换器Cb输出二端口的负极；The power regulation unit of phase B is composed of two bipolar direct AC-AC converters; the secondary side winding Ta3 of the phase A transformer is the AC input of the BT-AC converter Ab; the secondary side winding Tc3 of the phase C transformer is the AC input of the BT- The AC input of the AC converter Cb; the negative pole of the two output ports of the converter Ab is connected to the positive pole of the two output ports of the converter Cb to form a power conversion unit applied to the B phase; the output of the power conversion unit is two ports, and its positive pole is converted The positive pole of the two-port output of the converter Ab, and the negative pole of the two-port output of the converter Cb;
C相的功率调节单元由两个双极性直接式AC-AC变换器组成；A相变压器二次侧绕组Ta4为BT-AC变换器Ac的交流输入；B相变压器二次侧绕组Tb4为BT-AC变换器Bc的交流输入；变换器Ac输出二端口的负极与变换器Bc输出二端口的正极相连，构成应用于C相的功率变换单元；功率变换单元的输出为二端口，其正极为变换器Ac输出二端口的正极，负极为变换器Bc输出二端口的负极。The power regulation unit of phase C is composed of two bipolar direct AC-AC converters; the secondary side winding Ta4 of the phase A transformer is the AC input of the BT-AC converter Ac; the secondary winding Tb4 of the phase B transformer is the AC input of the BT - the AC input of the AC converter Bc; the negative pole of the two output ports of the converter Ac is connected to the positive pole of the two output ports of the converter Bc to form a power conversion unit applied to the C phase; the output of the power conversion unit is two ports, and its positive pole is The converter Ac outputs the positive pole of the two ports, and the negative pole outputs the negative pole of the two ports of the converter Bc.
双极性直接式AC-AC变换器BT-AC由输入滤波电容、H桥、信号控制单元组成；其中，H桥由正、负桥臂构成；The bipolar direct AC-AC converter BT-AC is composed of an input filter capacitor, an H-bridge, and a signal control unit; among them, the H-bridge is composed of positive and negative bridge arms;
输入滤波电容为高频薄膜电容；输入滤波电容一端与单相交流输入的正极连接，另一端与单相交流输入的负极连接；H桥的每个桥臂由4个全控型功率开关管、1个箝位电容构组成；正、负极性桥臂的一端与单相交流电源的正极连接，另一端与负极连接；正、负极性桥臂对地各有一个输出端口，两个桥臂构成二端输出端口。The input filter capacitor is a high-frequency film capacitor; one end of the input filter capacitor is connected to the positive pole of the single-phase AC input, and the other end is connected to the negative pole of the single-phase AC input; each bridge arm of the H-bridge consists of 4 fully-controlled power switch tubes, Composed of a clamping capacitor structure; one end of the positive and negative bridge arms is connected to the positive pole of the single-phase AC power supply, and the other end is connected to the negative pole; each of the positive and negative polarity bridge arms has an output port to the ground, and the two bridge arms constitute Two-terminal output port.
正极性桥臂的全控型功率开关管由上到下依次为S2、S1、S1c、S2c；S2的发射极与单相交流电源的正极连接，集电极与S1的集电极连接；S1的发射极与S1c的集电极连接，S1c的发射极与S2c的发射极连接；S2c的集电极与单相交流电源的负极连接；箝位电容C3一端与S1的集电极相连，另一端与S1c的发射极相连；正极性桥臂的输出端由开关管S1的发射极与S1c的集电极之间引出。The full-control power switch tubes of the positive bridge arm are S 2 , S 1 , S 1c , and S 2c from top to bottom; the emitter of S 2 is connected to the positive pole of the single-phase AC power supply, and the collector is connected to the collector of S 1 Electrode connection; the emitter of S 1 is connected to the collector of S 1c , the emitter of S 1c is connected to the emitter of S 2c ; the collector of S 2c is connected to the negative pole of the single-phase AC power supply; one end of clamping capacitor C 3 is connected to The collector of S 1 is connected, and the other end is connected with the emitter of S 1c ; the output end of the positive bridge arm is drawn between the emitter of switch S 1 and the collector of S 1c .
构成负极性桥臂的全控型功率开关管由上到下依次为S2p、S1p、S1cp、S2cp；S2p的发射极与单相交流电源的正极连接，集电极与S1p的集电极连接；S1p的发射极与S1cp的集电极连接；S1cp的发射极与S2cp的发射极连接；S2cp的集电极与单相交流电源的负极连接；箝位电容C2箝位在开关管S1p的集电极与S1cp的发射极之间引出。The fully-controlled power switch tubes that constitute the negative bridge arm are S 2p , S 1p , S 1cp , and S 2cp from top to bottom; the emitter of S 2p is connected to the positive pole of the single-phase AC power supply, and the collector is connected to the positive pole of S 1p The collector is connected; the emitter of S 1p is connected to the collector of S 1cp ; the emitter of S 1cp is connected to the emitter of S 2cp ; the collector of S 2cp is connected to the negative pole of the single-phase AC power supply; the clamp capacitor C 2 is clamped It is drawn between the collector of the switch tube S 1p and the emitter of S 1cp .
图4为双极性直接式AC-AC变换器BT-AC拓扑结构；由图7可知，BT-AC变换器的输入端与单相交流电源连接，变换器从电源获得50Hz正弦交流电能Vin，经过BT-AC变换器变换，然后将电能送到LC低通滤波器的输入端，经过滤波后得到50Hz正弦交流电。Figure 4 shows the BT-AC topology of the bipolar direct AC-AC converter; it can be seen from Figure 7 that the input end of the BT-AC converter is connected to a single-phase AC power supply, and the converter obtains 50Hz sinusoidal AC power V in from the power supply , transformed by the BT-AC converter, and then the electric energy is sent to the input end of the LC low-pass filter, and a 50Hz sinusoidal alternating current is obtained after filtering.
图5为双极性直接式AC-AC变换器BT-AC的控制原理图；其中，Vin为单相工频交流电源的输入电压，d1和d2分别为AC-AC变换器正、负极性桥臂的调制比；Uc为频率12kHz；峰值0到1的三角载波；输入电压Vin与0电位比较产生50Hz的方波信号，调制波与三角载波比较产生另一个方波信号，两个方波信号做逻辑运算产生驱动对应开关管的PWM驱动信号，当驱动信号为高电平时，对应的开关管开通，当驱动信号为0电平时，对应的开关管关断。Figure 5 is the control schematic diagram of the bipolar direct AC-AC converter BT-AC; among them, Vin is the input voltage of the single-phase power frequency AC power supply, and d1 and d2 are the positive and negative polarity bridges of the AC-AC converter respectively The modulation ratio of the arm; Uc is the frequency 12kHz; the triangular carrier wave with a peak value of 0 to 1; the input voltage Vin is compared with the 0 potential to generate a 50Hz square wave signal, and the modulation wave is compared with the triangular carrier wave to generate another square wave signal, two square wave signals Perform logic operations to generate a PWM drive signal to drive the corresponding switch tube. When the drive signal is at high level, the corresponding switch tube is turned on, and when the drive signal is at 0 level, the corresponding switch tube is turned off.
如图6所示，Buck型直接式AC-AC变换器UT-AC每相一个；Buck型直接式AC-AC变换器UT-AC由交流输入电源、两个输入电容、四个全控型功率开关管IGBT组成；电容C1的负极与电容C2的正极相连；电容C1的正极与电源的正极相连；电容C2的负极与电源的负极相连；四个IGBT从上到下依次为T1、T2、T3、T4；T1的集电极与C1的正极相连，发射极与T2的集电极连接；T2的发射极连接至T3的发射极；T3的集电极与T4的发射极连接；T4的集电极与电容C2的负极相连；C1的负极与T2的发射极连接；T1的发射极为桥臂的正极输出，T3的集电极为桥臂的负极输出，这两个端口构成Buck型直接式AC-AC变换器UT-AC的输出二端口。As shown in Figure 6, there is one Buck-type direct AC-AC converter UT-AC for each phase; the Buck-type direct AC-AC converter UT-AC consists of an AC input power supply, two input capacitors, and four fully-controlled power Composed of switching tube IGBT; the negative pole of capacitor C1 is connected to the positive pole of capacitor C2; the positive pole of capacitor C1 is connected to the positive pole of the power supply; the negative pole of capacitor C2 is connected to the negative pole of the power supply; the four IGBTs are T1, T2, T3 from top to bottom , T4; the collector of T1 is connected to the positive pole of C1, and the emitter is connected to the collector of T2; the emitter of T2 is connected to the emitter of T3; the collector of T3 is connected to the emitter of T4; the collector of T4 is connected to the capacitor The negative pole of C2 is connected; the negative pole of C1 is connected with the emitter of T2; the emitter of T1 is the positive output of the bridge arm, and the collector of T3 is the negative output of the bridge arm. These two ports constitute a Buck type direct AC-AC converter There are two output ports of UT-AC.
三相多绕组隔离变压器的A相输入绕组为Ta1，A相输出绕组为Ta2、Ta3、Ta4，变比为Ta1：Ta2：Ta3：Ta4＝2：2：1：1；B相输入绕组为Tb1，B相输出绕组为Tb2、Tb3、Tb4，变比为Tb1：Tb2：Tb3：Tb4＝2：2：1：1；C相输入绕组为Tc1，C相输出绕组为Tc2、Tc3、Tc4，变比为Tc1：Tc2：Tc3：Tc4＝2：2：1：1；变压器的所有绕组之间均隔离。The A-phase input winding of the three-phase multi-winding isolation transformer is Ta1, the A-phase output winding is Ta2, Ta3, Ta4, and the transformation ratio is Ta1:Ta2:Ta3:Ta4=2:2:1:1; the B-phase input winding is Tb1 , the B-phase output windings are Tb2, Tb3, Tb4, and the transformation ratio is Tb1:Tb2:Tb3:Tb4=2:2:1:1; the C-phase input winding is Tc1, and the C-phase output windings are Tc2, Tc3, Tc4. The ratio is Tc1: Tc2: Tc3: Tc4 = 2:2:1:1; all windings of the transformer are isolated from each other.
LC低通滤波器每相一个；LC低通滤波器由输出滤波电感、输出滤波电容组成；电感L与电容C组成二端口；LC低通滤波器的输入二端口与每相各模块级联后的输出二端口连接，输出端口即为各相电压出端口。One LC low-pass filter for each phase; LC low-pass filter is composed of output filter inductor and output filter capacitor; inductance L and capacitor C form two ports; the input two ports of LC low-pass filter are cascaded with each module of each phase The two output ports are connected, and the output port is the output port of each phase voltage.
如图1、图2所示，一条馈线末端节点A、B、C三相交流电源分别对应接入三相多绕组隔离变压器的输入绕组Ta1、Tb1、Tc1；A相接绕组Ta1的正极，B相接绕组Tb1的正极，C相接绕组Tc1的正极；绕组Ta1、Tb1、Tc1的负极连接在一起，连接点为N1；A相变压器的二次侧绕组Ta2接Buck型直接式AC-AC变换器Aa的输入端，绕组Ta3接BT-AC变换器Ab的输入端，绕组Ta4接BT-AC变换器Ac的输入端；B相变压器的二次侧绕组Tb2接BT-AC变换器Ba的输入端，绕组Tb3接Buck型直接式AC-AC变换器Bb的输入端，绕组Tb4接BT-AC变换器Bc的输入端；C相变压器的二次侧绕组Tc2接BT-AC变换器Ca的输入端，绕组Tc3接BT-AC变换器Cb的输入端，绕组Tc4接Buck型直接式AC-AC变换器Cc的输入端；Aa变换器输出端口的负极接Ba变换器输出端口的正极，Ba变换器输出端口的负极极与Ca变换器输出端口的正极相连；Ab变换器输出端口的负极接Bb变换器输出端口的正极，Bb变换器输出端口的负极极与Cb变换器输出端口的正极相连；Ac变换器输出端口的负极接Bc变换器输出端口的正极，Bc变换器输出端口的负极极与Cc变换器输出端口的正极相连；Ca变换器输出端口的负极、Cb变换器输出端口的负极、Cc变换器输出端口的负极连在一起，连接点为N2；Aa、Ba、Ca共用一个LC滤波器；Ab、Bb、Cb共用一个LC滤波器；Ac、Bc、Cc共用一个LC滤波器；各相滤波器的输入二端口与各自相所有模块级联后的输出二端口连接；Aa变换器输出端口的正极、Ab变换器输出端口的正极、Ac变换器输出端口的正极分别对应为A、B、C三相电压输出，且均连接于另一条馈线的末端。As shown in Figure 1 and Figure 2, the three-phase AC power supply at the end nodes A, B, and C of a feeder is respectively connected to the input windings Ta1, Tb1, and Tc1 of the three-phase multi-winding isolation transformer; A is connected to the positive pole of the winding Ta1, B Phase C is connected to the positive pole of winding Tb1, and phase C is connected to the positive pole of winding Tc1; the negative poles of winding Ta1, Tb1, and Tc1 are connected together, and the connection point is N1; the secondary side winding Ta2 of phase A transformer is connected to Buck type direct AC-AC conversion The input end of transformer Aa, the winding Ta3 is connected to the input end of BT-AC converter Ab, the winding Ta4 is connected to the input end of BT-AC converter Ac; the secondary side winding Tb2 of B-phase transformer is connected to the input of BT-AC converter Ba Terminal, winding Tb3 is connected to the input terminal of Buck type direct AC-AC converter Bb, winding Tb4 is connected to the input terminal of BT-AC converter Bc; the secondary side winding Tc2 of the C-phase transformer is connected to the input terminal of BT-AC converter Ca terminal, the winding Tc3 is connected to the input terminal of the BT-AC converter Cb, and the winding Tc4 is connected to the input terminal of the Buck type direct AC-AC converter Cc; the negative pole of the output port of the Aa converter is connected to the positive pole of the output port of the Ba converter, and Ba transforms The negative pole of the output port of the converter is connected to the positive pole of the output port of the Ca converter; the negative pole of the output port of the Ab converter is connected to the positive pole of the output port of the Bb converter, and the negative pole of the output port of the Bb converter is connected to the positive pole of the output port of the Cb converter; The negative pole of the output port of the AC converter is connected to the positive pole of the output port of the Bc converter, and the negative pole of the output port of the Bc converter is connected to the positive pole of the output port of the Cc converter; the negative pole of the output port of the Ca converter, the negative pole of the output port of the Cb converter, The negative poles of the output ports of the Cc converter are connected together, and the connection point is N2; Aa, Ba, and Ca share one LC filter; Ab, Bb, and Cb share one LC filter; Ac, Bc, and Cc share one LC filter; The two input ports of the phase filter are connected to the two output ports after cascading all the modules of each phase; the positive pole of the output port of the Aa converter, the positive pole of the output port of the Ab converter, and the positive pole of the output port of the Ac converter correspond to A and B respectively. , C three-phase voltage output, and are connected to the end of another feeder.
(一)(one)
根据负载侧期望得到的电压，本发明可以有多种组合的PWM调制方式，具体如表1所示：According to the desired voltage on the load side, the present invention can have multiple combined PWM modulation modes, as shown in Table 1:
表1 PWM调制方式Table 1 PWM modulation method
(二)(two)
图4为本发明的电压调节的示意图；以A相为例，在平面相量坐标系下展示；UA1、UB1、UC1为三相电压相量量；-UA1、-UB1、-UC1为方向相反的三相电压相量；D1*UB1，D2*UC1为两个BT-AC变换器的输出电压相量；Uout为功率变换单元输出的电压相量，即为D1*UB1，D2*UC1的矢量合成；UA2为A相总的电压输出，它由Uout和UA1矢量合成得；Fig. 4 is a schematic diagram of the voltage regulation of the present invention; taking phase A as an example, it is displayed under the plane phasor coordinate system; UA1, UB1, and UC1 are three-phase voltage phasor quantities; -UA1, -UB1, and -UC1 are in opposite directions D1*UB1, D2*UC1 is the output voltage phasor of two BT-AC converters; Uout is the voltage phasor output by the power conversion unit, which is the vector of D1*UB1, D2*UC1 Synthesis; UA2 is the total voltage output of phase A, which is synthesized by Uout and UA1 vector;
图(a)为装置工作在负极性调压器模式，实现输入输出电压相位不变，幅值减小；Figure (a) shows that the device works in the negative voltage regulator mode, so that the phase of the input and output voltage remains unchanged and the amplitude decreases;
图(b)为装置工作在正极性调压器模式，实现输入输出电压相位不变，幅值减小；Figure (b) shows that the device works in the positive voltage regulator mode, so that the phase of the input and output voltage remains unchanged and the amplitude decreases;
图(c)为装置工作在移相器模式，实现输入输出电压幅值不变，相位改变；图(d)为装置工作在移相调压模式，实现输入输出电压和幅值均改变。Figure (c) shows that the device works in the phase shifter mode, and the input and output voltage amplitudes remain unchanged, while the phase changes; Figure (d) shows that the device works in the phase shifting voltage regulation mode, and both the input and output voltages and amplitudes change.
(三)(three)
图5(a)展示了当变压器变比为Ta1：Ta2：Ta3：Ta4＝1：1：1：1时的A相电压补偿范围；VcN和-VcN为C相的输入电压相量；VbN和-VbN为B相的输入电压相量；功率变换单元的输出电压相量即补偿到A相的电压相量从原点出发，终点在菱形内(包含菱形边界)；Figure 5(a) shows the phase A voltage compensation range when the transformer ratio is Ta1: Ta2: Ta3: Ta4 = 1:1:1:1; VcN and -VcN are the input voltage phasors of C phase; VbN and -VbN is the input voltage phasor of phase B; the output voltage phasor of the power conversion unit is compensated to the voltage phasor of phase A starting from the origin and ending within the rhombus (including the rhombus boundary);
图(b)展示了三相电压补偿范围，同样各相变压器变比均为1：1：1：1。Figure (b) shows the three-phase voltage compensation range, and the transformer ratio of each phase is also 1:1:1:1.
(四)(Four)
图9为LC低通滤波器的电路原理图；其中，对于电感Lf可以流过直流阻碍交流，特别是高频的交流；电容Cf可以流通交流阻碍直流，通过设计LC的参数最终达到滤除高频谐波，保证输出高质量的50Hz正弦交流电压的目的。其中Lf和Cf的参数设计，参照下式：Figure 9 is the circuit schematic diagram of the LC low-pass filter; among them, the inductor L f can flow through the DC to block the AC, especially the high-frequency AC; In addition to high-frequency harmonics, the purpose of ensuring the output of high-quality 50Hz sinusoidal AC voltage. The parameter design of L f and C f refers to the following formula:
其中，ωL为LC滤波器的截止角频率，V0为输出电压，ω1为输入交流电源的角频率。Where, ω L is the cut-off corner frequency of the LC filter, V 0 is the output voltage, and ω 1 is the corner frequency of the input AC power supply.
(五)(five)
为了更好的验证本发明的优越性，搭建了一台单相应用功能样机，样机的参数如下表2所示：In order to better verify the superiority of the present invention, a single-phase application functional prototype was built, and the parameters of the prototype are shown in Table 2 below:
表2样机参数Table 2 prototype parameters
(六)(six)
图10为调幅值模式输出正极性补偿电压波形图；UAO、UBU、UO分别为输入电压，补偿电压，总的输出电压；图11-15中相同参数代表相同意义，图15中IO为总的输出电流；Figure 10 is the waveform diagram of the positive polarity compensation voltage output in the amplitude modulation mode; UAO, UBU, and UO are the input voltage, compensation voltage, and total output voltage respectively; the same parameters in Figure 11-15 represent the same meaning, and IO in Figure 15 is the total output current;
由图10、图11可以看出，装置可以实现不变相位，调节电压；It can be seen from Figure 10 and Figure 11 that the device can achieve constant phase and adjust voltage;
由图12、图13可以看出装置可以实现不变电压，调节相位；It can be seen from Figure 12 and Figure 13 that the device can realize constant voltage and adjust phase;
由图14、图15可以看出装置可以实现移相调压，并且带负载正常工作；It can be seen from Figure 14 and Figure 15 that the device can realize phase-shifting and voltage regulation, and it can work normally with load;
综上，本发明可以实现节点电压和功率的柔性调节并具有一定的保护功能。To sum up, the present invention can realize flexible regulation of node voltage and power and has a certain protection function.
Claims (9)
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| CN111342680A (en) * | 2020-03-09 | 2020-06-26 | 西南交通大学 | Power electronic transformer applied to through power supply |
| CN112072639A (en) * | 2020-08-11 | 2020-12-11 | 东南大学 | Grid flexible closed loop controller topology shared by modules |
| CN112436550A (en) * | 2020-11-17 | 2021-03-02 | 青岛大学 | Medium-voltage photovoltaic power generation system |
| CN112436548A (en) * | 2020-11-17 | 2021-03-02 | 青岛大学 | Photovoltaic power generation system |
| CN112531783A (en) * | 2020-12-07 | 2021-03-19 | 青岛大学 | Photovoltaic power generation system with SOP function |
| CN112909993A (en) * | 2021-01-21 | 2021-06-04 | 山东大学 | Three-phase current unbalance compensation method for medium-voltage photovoltaic power generation system |
| CN113595067A (en) * | 2021-07-19 | 2021-11-02 | 东北电力大学 | Novel deep and distant sea wind power transmission system based on medium-low-power frequency collection |
| CN113872452A (en) * | 2021-07-15 | 2021-12-31 | 东北电力大学 | A direct AC-AC converter based on three-phase core multi-winding transformer |
| CN114553046A (en) * | 2022-01-21 | 2022-05-27 | 东北电力大学 | Three-phase alternating current-direct current converter based on single-phase transformer cascade connection |
| CN116111844A (en) * | 2023-04-13 | 2023-05-12 | 深圳市恒运昌真空技术有限公司 | Dual-switch converter and control method thereof |
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| CN111342680A (en) * | 2020-03-09 | 2020-06-26 | 西南交通大学 | Power electronic transformer applied to through power supply |
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| CN112072639A (en) * | 2020-08-11 | 2020-12-11 | 东南大学 | Grid flexible closed loop controller topology shared by modules |
| CN112436550A (en) * | 2020-11-17 | 2021-03-02 | 青岛大学 | Medium-voltage photovoltaic power generation system |
| CN112436548A (en) * | 2020-11-17 | 2021-03-02 | 青岛大学 | Photovoltaic power generation system |
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| CN112531783A (en) * | 2020-12-07 | 2021-03-19 | 青岛大学 | Photovoltaic power generation system with SOP function |
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| CN112909993A (en) * | 2021-01-21 | 2021-06-04 | 山东大学 | Three-phase current unbalance compensation method for medium-voltage photovoltaic power generation system |
| CN113872452A (en) * | 2021-07-15 | 2021-12-31 | 东北电力大学 | A direct AC-AC converter based on three-phase core multi-winding transformer |
| CN113595067A (en) * | 2021-07-19 | 2021-11-02 | 东北电力大学 | Novel deep and distant sea wind power transmission system based on medium-low-power frequency collection |
| CN114553046A (en) * | 2022-01-21 | 2022-05-27 | 东北电力大学 | Three-phase alternating current-direct current converter based on single-phase transformer cascade connection |
| CN116111844A (en) * | 2023-04-13 | 2023-05-12 | 深圳市恒运昌真空技术有限公司 | Dual-switch converter and control method thereof |
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