JP7764263B2

JP7764263B2 - Power Conversion Device

Info

Publication number: JP7764263B2
Application number: JP2022015853A
Authority: JP
Inventors: 彰訓加藤
Original assignee: Kawamura Electric Inc
Current assignee: Kawamura Electric Inc
Priority date: 2022-02-03
Filing date: 2022-02-03
Publication date: 2025-11-05
Anticipated expiration: 2042-02-03
Also published as: JP2023113461A

Description

本発明は、三相交流電力を変圧器を使用して多相電力に変換した後、直流に変換する電力変換装置に関する。 The present invention relates to a power conversion device that converts three-phase AC power into multi-phase power using a transformer, and then converts it back into DC.

従来より高電圧の直流電力を得るために、三相交流を変圧器と整流器を使用して直流に変換する電力変換装置がある。
例えば特許文献１では、スター結線された１次巻線とスター結線された２次巻線とデルタ結線された３次巻線を備えた変圧器を使用し、１次巻線に三相交流電源を接続し、２次巻線と３次巻線とで計１２相の電圧を生成して整流し、直流電力を生成した。 2. Description of the Related Art Conventionally, there has been a power conversion device that converts three-phase AC power into DC power using a transformer and a rectifier in order to obtain high-voltage DC power.
For example, in Patent Document 1, a transformer having a star-connected primary winding, a star-connected secondary winding, and a delta-connected tertiary winding is used, a three-phase AC power source is connected to the primary winding, and a total of 12 phases of voltage are generated by the secondary winding and tertiary winding, which are then rectified to generate DC power.

特開２００８－２９５１５５号公報Japanese Patent Application Laid-Open No. 2008-295155

上記特許文献１に開示されている電力変換装置の変圧器は、上述したように２次側にスター結線とデルタ結線の２つの巻線を設けることで１２相の電圧を生成し、三相交流をそのまま整流する場合に比べてリップルの小さい電圧を得ることを可能とし、平滑化するための設備を簡素化できた。
しかしながら、変圧器２次側のデルタ結線、３次側のスター結線の２つの巻線は何れも同様の巻数であり巻回数も多いため、コアを小さくできず変圧器が大型なものとなっていた。 The transformer of the power conversion device disclosed in Patent Document 1 generates a 12-phase voltage by providing two windings, one star-connected and one delta-connected, on the secondary side, as described above, making it possible to obtain a voltage with smaller ripples than when three-phase AC is directly rectified, and simplifying the equipment required for smoothing.
However, since the two windings, the delta-connected winding on the secondary side of the transformer and the star-connected winding on the tertiary side, both have the same number of turns and are large, the core cannot be made small and the transformer is large.

そこで、本発明はこのような問題点に鑑み、多相の電圧を生成する変圧器を小型にすることが可能な電力変換装置を提供することを目的としている。 In light of these problems, the present invention aims to provide a power conversion device that enables the miniaturization of transformers that generate polyphase voltages.

上記課題を解決する為に、請求項１の発明は、変圧器を使用して三相電力を多相電力に変換し、変換した多相電力を整流手段で整流して直流変換する電力変換装置であって、変圧器は、三相電源が接続される１次側の第１巻線と、２次側を構成してそれぞれ異なる三相電力を生成する第２巻線及び第３巻線とが、相毎に異なる脚を有する共通の鉄心に巻回され、第１巻線はデルタ結線或いはスター結線の何れかで結線される一方、第２巻線はスター結線されると共に、第３巻線の３つの巻線は第２巻線の個々の巻線の中性点から７３％の位置からそれぞれ分岐して形成され、分岐後の第３巻線は、第２巻線の７３％の巻数で分岐基の第２巻線とは異なる相の鉄心にそれぞれ巻回されて三相を生成し、第２巻線の各相の出力と合わせて６相の電流が２次側から出力されることを特徴とする。 To solve the above problem, the invention of claim 1 is a power conversion device that uses a transformer to convert three-phase power to polyphase power, and then rectifies the converted polyphase power using rectifying means for DC conversion. The transformer has a first winding on the primary side to which a three-phase power source is connected, and second and third windings that form the secondary side and generate different three-phase power, wound around a common core with different legs for each phase. The first winding is connected in either a delta or star connection, while the second winding is star connected. The three windings of the third winding are each formed by branching off from positions 73% from the neutral point of each winding of the second winding. The branched third windings are wound on iron cores of different phases from the second winding at 73% of the number of turns of the second winding to generate three phases, and together with the output of each phase of the second winding, six phases of current are output from the secondary side.

本発明によれば、第３巻線は第２巻線の途中から分岐して形成されるため、巻線の一部を第２巻線に肩代わりさせることができ巻数を削減できる。よって、変圧器全体の巻数を削減でき小型化が可能となる。
また、第３巻線は第２巻線の中性点から７３％の位置で分岐され、第２巻線の７３％の巻数で分岐基の第２巻線とは異なる相の鉄心にそれぞれ巻回されることで、第２巻線と第３巻線とで、全波整流後の波形を３０度位相がズレた全１２相の波形にすることが可能であり、リップルの小さい直流を得ることが可能となる。 According to the present invention, the third winding is formed by branching off from the middle of the second winding, so that part of the winding can be taken over by the second winding, thereby reducing the number of turns of the entire transformer and enabling miniaturization.
In addition, the third winding is branched off at a position 73% from the neutral point of the second winding, and is wound around an iron core of a different phase from the second winding at the branch base with 73% of the number of turns of the second winding.This makes it possible for the second and third windings to make the waveform after full-wave rectification into a waveform with a total of 12 phases that is 30 degrees out of phase, making it possible to obtain direct current with little ripple.

本発明に係る電力変換装置の一例を示す回路図である。1 is a circuit diagram showing an example of a power conversion device according to the present invention. 図１の変圧器の各相の電圧のベクトル説明図であり、（ａ）は１次巻線の相電圧、（ｂ）は２次巻線である第２巻線及び第３巻線の相電圧を示している。2A and 2B are vector explanatory diagrams of the voltages of each phase of the transformer of FIG. 1, where (a) shows the phase voltage of the primary winding, and (b) shows the phase voltage of the second and third windings, which are secondary windings. ２次側の線間電圧の説明図であり、（ａ）はベクトル図、（ｂ）は波形図を示している。1A and 1B are diagrams illustrating a line voltage on the secondary side, in which FIG. 1A is a vector diagram and FIG. 1B is a waveform diagram. 電力変換装置の他の形態を示す変圧器の結線説明図である。FIG. 10 is an explanatory diagram of transformer connections showing another embodiment of the power conversion device. 図４の変圧器の２次側各相の電圧のベクトル図を示している。5 shows a vector diagram of the voltage of each phase on the secondary side of the transformer of FIG. 4 .

以下、本発明を具体化した実施の形態を、図面を参照して詳細に説明する。図１は本発明に係る電力変換装置の一例を示す回路図であり、三相電源３から供給される三相電力を多相に変換する変圧器１と、変圧器１の２次側出力を整流する整流手段としての全波整流回路２とを有している。
変圧器１は、１次側巻線Ｌ１を構成する第１巻線１１、２次側巻線Ｌ２を構成する第２巻線１２、第３巻線１３の３つの巻線を有し、何れも三相電力に対応するための３つの巻回部（１１ａ～１１ｃ、１２ａ～１２ｃ、１３ａ～１３ｃ）を有し、何れもスター結線されている。但し、第３巻線１３は、後述するように一部が第２巻線１２と共通となっている。尚、三相をＲ相、Ｓ相、Ｔ相とし、図１では左からＲ相、Ｓ相、Ｔ相として説明する。 1 is a circuit diagram showing an example of a power conversion device according to the present invention, which includes a transformer 1 that converts three-phase power supplied from a three-phase power source 3 into multi-phase power, and a full-wave rectifier circuit 2 that rectifies the secondary side output of the transformer 1.
The transformer 1 has three windings: a first winding 11 constituting the primary winding L1, a second winding 12 constituting the secondary winding L2, and a third winding 13. Each has three winding sections (11a to 11c, 12a to 12c, 13a to 13c) to accommodate three-phase power, and all are star-connected. However, as will be described later, a portion of the third winding 13 is shared with the second winding 12. The three phases are referred to as R, S, and T phases, and will be described from left to right in FIG. 1 as R, S, and T phases.

第１巻線１１のＲ１，Ｓ１，Ｔ１の３端子（１次側端子）に三相電源３の各相が接続されている。また、第２巻線１２は３つの出力端子（２次側端子）Ｒ２，Ｓ２，Ｔ２を備え、第３巻線１３は３つの出力端子（２次側端子）Ｒ３，Ｓ３，Ｔ３を備え、それぞれ三相電力を出力する。 The first winding 11 has three terminals (primary terminals) R1, S1, and T1 connected to each phase of the three-phase power supply 3. The second winding 12 has three output terminals (secondary terminals) R2, S2, and T2, and the third winding 13 has three output terminals (secondary terminals) R3, S3, and T3, each of which outputs three-phase power.

各巻線が巻回される鉄心４は、三相電力を形成するための３本の脚４ａ～４ｃを有し、各巻線１１，１２，１３の巻回部（１１ａ～１１ｃ、１２ａ～１２ｃ、１３ａ～１３ｃ）は、この３本の脚４ａ～４ｃに相毎に巻回されている。
但し、第３巻線１３は、第２巻線１２の途中から分岐して形成されている。正確には、中性点Ｑから７３％の位置で分岐され、分岐基の第２巻線１２とは異なる相の鉄心脚に巻回して形成されている。 The iron core 4 around which each winding is wound has three legs 4a to 4c for generating three-phase power, and the winding portions (11a to 11c, 12a to 12c, 13a to 13c) of each winding 11, 12, 13 are wound around these three legs 4a to 4c for each phase.
However, the third winding 13 is formed by branching off from the middle of the second winding 12. To be precise, it branches off at a position 73% from the neutral point Q and is wound around an iron core leg of a different phase from the second winding 12 at the branch base.

具体的に、第３巻線１３のＲ相の巻線１３ａは、第２巻線１２のＴ相の巻線１２ｃから分岐され、第３巻線１３のＳ相の巻線１３ｂは、第２巻線１２のＲ相の巻線１２ａから分岐されている。そして、第３巻線１３のＴ相の巻線１３ｃは、第２巻線１２のＳ相の巻線１２ｂから分岐されている。
そして、第３巻線１３は第２巻線１２に比べて巻回数が少なく、第２巻線１２と第３巻線１３とは後述する理由により１：（√３－１）の比、即ち第３巻線１３は第２巻線１２に対して約７３％の巻数で巻回されている。 Specifically, the R-phase winding 13a of the third winding 13 branches off from the T-phase winding 12c of the second winding 12, and the S-phase winding 13b of the third winding 13 branches off from the R-phase winding 12a of the second winding 12. The T-phase winding 13c of the third winding 13 branches off from the S-phase winding 12b of the second winding 12.
The third winding 13 has fewer turns than the second winding 12, and the ratio between the second winding 12 and the third winding 13 is 1:(√3-1) for reasons described below. In other words, the third winding 13 has approximately 73% of the number of turns of the second winding 12.

図２は、このように構成された変圧器１の各相に発生する電圧のベクトル図であり、（ａ）は１次側巻線Ｌ１の各相の電圧、（ｂ）は２次側巻線Ｌ２の各相の電圧を示している。１次側（第１巻線１１）のＲ相電圧Ｖ_Ｒ１、Ｓ相の電圧Ｖ_Ｓ１、Ｔ相の電圧Ｖ_Ｔ１、また２次側の第２巻線１２のＲ相電圧Ｖ_Ｒ２、Ｓ相の電圧Ｖ_Ｓ２、Ｔ相の電圧Ｖ_Ｔ２は、互いに１２０度の位相差を有している。
一方３次巻線１３のＲ相電圧Ｖ_Ｒ３、Ｓ相の電圧Ｖ_Ｓ３、Ｔ相の電圧Ｖ_Ｔ３は、第３巻線の各巻線が第２巻線から分岐されているため、図２に示すように中性点Ｑは第２巻線１２と共通となり、この第３巻線１３は全体でスター結線となっている。 2 is a vector diagram of the voltages generated in each phase of the transformer 1 configured as above, where (a) shows the voltages of each phase of the primary winding L1 and (b) shows the voltages of each phase of the secondary winding L2. The R-phase voltage V _R1 , S-phase voltage V _S1 , and T-phase voltage V _T1 of the primary side (first winding 11) and the R-phase voltage V _R2 , S-phase voltage V _S2 , and T-phase voltage V _T2 of the second winding 12 on the secondary side have a phase difference of 120 degrees from one another.
On the other hand, the R-phase voltage V _R3 , S-phase voltage V _S3 , and T-phase voltage V _T3 of the tertiary winding 13 are each branched off from the secondary winding, so as shown in FIG. 2 , the neutral point Q is common to the secondary winding 12, and the tertiary winding 13 as a whole is star-connected.

更に、図２（ｂ）に示すように、第２巻線１２から出力される三相の電圧Ｖ_Ｒ２、Ｖ_Ｓ２、Ｖ_Ｔ２、は１次側巻線Ｌ１と同相の電圧を生成するが、第３巻線１３により生成される電圧Ｖ_Ｒ３、Ｖ_Ｓ３、Ｖ_Ｔ３は、第２巻線１２の個々の相に対して１２０度進んだ電圧（或いは１２０度遅れた電圧）が生成される。
そして、第３巻線１３単体の出力は、第２巻線１２との巻線比により、出力される電圧は第２巻線１２の７３％となる。 Furthermore, as shown in Figure 2(b), the three-phase voltages V _R2 , V _S2 , and V _T2 output from the second winding 12 generate voltages that are in phase with the primary winding L1, but the voltages V _R3 , V _S3 , and V _T3 generated by the third winding 13 are voltages that lead (or lag) the individual phases of the second winding 12 by 120 degrees.
The output voltage of the third winding 13 alone is 73% of that of the second winding 12 due to the winding ratio with the second winding 12 .

図３は、Ｒ２端子を基準にした場合のＴ２，Ｔ３端子に発生する電圧（端子間電圧）の説明図であり、（ａ）はベクトル図、（ｂ）は波形図を示している。
この図３を参照して、第３巻線１３の第２巻線１２の分岐位置７３％、及び第２巻線に対する巻数比１：０．７３とする理由を説明する。
図３では、Ｒ２－Ｔ３端子間電圧Ｖ_{Ｒ１－Ｔ３}の大きさが、Ｒ２－Ｔ２端子間電圧Ｖ_{Ｒ２－Ｔ２}の大きさに等しく且つ３０度の位相差を有していることを示している。このような電圧を発生させるには、図３に示すように第３巻線１３の中性点Ｑ－Ｔ３端子間電圧ｅ_Ｔ３が、Ｒ２端子と１８０度の位相差があり、且つ発生電圧が第２巻線１２に対して√３－１倍、即ち７３％の大きさである必要がある。
そのために、第２巻線１２に肩代わりさせている電圧のベクトルｅ_Ｓ２と、第３巻線１３で発生する電圧Ｖ_{Ｓ２－Ｔ３}の絶対値を等しく、且つ大きさを第２巻線１２の相電圧に対して７３％としている。 3A and 3B are diagrams illustrating the voltages (terminal voltages) generated at the T2 and T3 terminals when the R2 terminal is used as a reference, where (a) is a vector diagram and (b) is a waveform diagram.
The reasons for the branch position of the third winding 13 to the second winding 12 being 73% and the turns ratio to the second winding being 1:0.73 will be explained with reference to FIG.
3 shows that the magnitude of the voltage V _R1-T3 between the R2-T3 terminals is equal to the magnitude of the voltage V _R2-T2 between the R2-T2 terminals and has a phase difference of 30 degrees. To generate such a voltage, as shown in FIG. 3, the voltage e _T3 between the neutral point Q-T3 terminal of the third winding 13 needs to have a phase difference of 180 degrees with the R2 terminal, and the generated voltage needs to be √3-1 times, or 73%, the magnitude of the second winding 12.
For this purpose, the absolute values of the voltage vector e _S2 taken over by the second winding 12 and the voltage V _S2-T3 generated in the third winding 13 are set to be equal, and the magnitude is set to 73% of the phase voltage of the second winding 12.

この結果、図３に示すように、Ｒ２端子を基準にしたＴ２端子、Ｔ３端子の電圧は、絶対値が等しく、位相は３０度ずれた波形となる。同様に、Ｓ２端子を基準としたＲ２，Ｒ３端子の電圧、Ｔ２を基準としたＳ２，Ｓ３端子の電圧も、互いに絶対値が等しく、位相は３０度ずれた波形としている。 As a result, as shown in Figure 3, the voltages at the T2 and T3 terminals, relative to the R2 terminal, have waveforms with the same absolute value but a phase difference of 30 degrees. Similarly, the voltages at the R2 and R3 terminals, relative to the S2 terminal, and the voltages at the S2 and S3 terminals, relative to T2, have waveforms with the same absolute value but a phase difference of 30 degrees.

このように生成された端子間電圧により、１８０度の位相の中で、それぞれ３０度づつずれた位相の６波形が生成される。そのため、これら生成された電圧を全波整流すると、３６０度の位相の中で３０度ずつずれた１２相の正極性波形を生成でき、リップルの小さい直流を得ることが可能となる。
そして、第３巻線１３は第２巻線１２の途中から分岐して形成されるため、巻線の一部を第２巻線１２に肩代わりさせることができ、巻数を削減できる。よって、変圧器１全体の巻数を削減でき小型化が可能となる。 The inter-terminal voltage generated in this way generates six waveforms, each with a phase difference of 30 degrees within a 180-degree phase. Therefore, when these generated voltages are full-wave rectified, 12 positive-polarity waveforms, each with a phase difference of 30 degrees within a 360-degree phase, can be generated, making it possible to obtain DC with little ripple.
Furthermore, since the third winding 13 is formed by branching off from the middle of the second winding 12, part of the winding can be taken over by the second winding 12, thereby reducing the number of turns. As a result, the number of turns of the entire transformer 1 can be reduced, enabling miniaturization.

図４は、電力変換装置の他の形態を示し、上記形態とは変圧器１の構成が異なっている。第２巻線１２から分岐された第３巻線１３の巻回先が上記形態とは異なり、第２巻線１２のＳ相から分岐された第３巻線１３はＲ相の脚４ａに巻回され、第２巻線１２のＴ相から分岐された第３巻線１３はＳ相の脚４ｂに巻回され、第２巻線１２のＲ相から分岐され第３巻線１３はＴ相の脚４ｃに巻回されている。尚、第３巻線１３の第２巻線１２からの分岐位置、第３巻線の巻回数は上記形態と同様である。 Figure 4 shows another form of power conversion device, in which the configuration of the transformer 1 is different from the above-described form. The winding destination of the third winding 13 branched off from the second winding 12 differs from the above-described form; the third winding 13 branched off from the S-phase of the second winding 12 is wound around the R-phase leg 4a, the third winding 13 branched off from the T-phase of the second winding 12 is wound around the S-phase leg 4b, and the third winding 13 branched off from the R-phase of the second winding 12 is wound around the T-phase leg 4c. Note that the branching position of the third winding 13 from the second winding 12 and the number of turns of the third winding are the same as in the above-described form.

図５は図４の結線の場合の２次側巻線Ｌ２のベクトル説明図である。図５に示すように、上記形態とは第３巻線１３により生成される電圧Ｖ_Ｒ３、Ｖ_Ｓ３、Ｖ_Ｔ３の大きさは同一であるが、位相が１２０度異なっている。
第３巻線１３により生成される電圧が、このような電圧位相であっても良く、２次側で発生する線間電圧は上記形態と同様であり、例えばＲ２端子を基準にしたＴ２端子、Ｔ３端子の電圧は互いに絶対値が等しく、位相は３０度ずれた波形となる。
そして整流後の波形は、１２相の正極性波形にでき、リップルの小さい直流を得ることが可能となる。 Fig. 5 is a vector diagram of the secondary winding L2 in the case of the connection in Fig. 4. As shown in Fig. 5, the voltages V _R3 , V _S3 , and V _T3 generated by the third winding 13 are the same in magnitude as in the above-mentioned configuration, but are out of phase by 120 degrees.
The voltage generated by the third winding 13 may have such a voltage phase, and the line voltage generated on the secondary side is similar to the above-described form. For example, the voltages at the T2 terminal and the T3 terminal with the R2 terminal as the reference have waveforms with the same absolute values and a phase difference of 30 degrees.
The waveform after rectification can be a 12-phase positive waveform, making it possible to obtain a DC current with small ripples.

尚、上記実施形態では、１次側巻線１１をスター結線としているが、デルタ結線しても良い。 In the above embodiment, the primary winding 11 is star-connected, but it may also be delta-connected.

１・・変圧器、２・・全波整流回路（整流手段）、３・・三相電源、４・・鉄心、１１・・第１巻線、１２・・第２巻線、１３・・第３巻線、Ｌ１・・１次側巻線、Ｌ２・・２次側巻線。 1. Transformer, 2. Full-wave rectifier circuit (rectifier means), 3. Three-phase power supply, 4. Iron core, 11. First winding, 12. Second winding, 13. Third winding, L1. Primary winding, L2. Secondary winding.

Claims

A power conversion device that converts three-phase power into polyphase power using a transformer, and rectifies the converted polyphase power with a rectifier to convert it into direct current,
The transformer has a first winding on a primary side to which a three-phase power supply is connected, and second and third windings constituting a secondary side and generating different three-phase power respectively, wound around a common iron core having different legs for each phase;
the first winding is connected in either a delta connection or a star connection, the second winding is star connected, and three windings of the third winding are formed by branching off from positions 73% from the neutral point of each winding of the second winding,
The third winding after branching is wound around an iron core of a different phase from the second winding of the branch base with 73% of the number of turns of the second winding, thereby generating three phases, and a six-phase current, combined with the outputs of each phase of the second winding, is output from the secondary side.