JP6931595B2 - Power converter and connection method of power converter - Google Patents

Power converter and connection method of power converter Download PDF

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JP6931595B2
JP6931595B2 JP2017225416A JP2017225416A JP6931595B2 JP 6931595 B2 JP6931595 B2 JP 6931595B2 JP 2017225416 A JP2017225416 A JP 2017225416A JP 2017225416 A JP2017225416 A JP 2017225416A JP 6931595 B2 JP6931595 B2 JP 6931595B2
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power conversion
phase
secondary side
primary
primary side
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JP2019097322A (en
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公久 古川
公久 古川
叶田　玲彦
玲彦 叶田
瑞紀 中原
瑞紀 中原
馬淵　雄一
雄一 馬淵
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Hitachi Ltd
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Hitachi Ltd
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Priority to PCT/JP2018/041106 priority patent/WO2019102839A1/en
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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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • 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
    • H02M5/40—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 with intermediate conversion into dc
    • H02M5/42—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 with intermediate conversion into dc by static converters
    • H02M5/44—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 with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/49—Combination of the output voltage waveforms of a plurality of converters

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Ac-Ac Conversion (AREA)
  • Rectifiers (AREA)
  • Dc-Dc Converters (AREA)

Description

本発明は、電力変換装置および電力変換装置の接続方法に関する。 The present invention relates to a power converter and a method of connecting the power converter.

本技術分野の背景技術として、下記特許文献１には、「図示のように、本発明の第１の態様において、複数のコンバータセル２０−１、２０−２、…、２０−Ｎ（ただし、Ｎは２以上の自然数）を備える電力変換装置１は、複数のコンバータセル２０−１、２０−２、…、２０−Ｎの各第１の交直変換器１１の交流側どうしが直列接続され、かつ、この複数のコンバータセルの各第４の交直変換器１４の交流側どうしが直列接続される。直列接続するコンバータセルの段数が増加するほど、交流電圧は多レベル（マルチレベル）化される。」と記載されている（明細書の段落００１９参照）。 As a background technique in the present technical field, the following Patent Document 1 states, "As shown in the figure, in the first aspect of the present invention, a plurality of converter cells 20-1, 20-2, ..., 20-N (however, however, In the power converter 1 having (N is a natural number of 2 or more), the AC sides of the first AC / DC converters 11 of the plurality of converter cells 20-1, 20-2, ..., 20-N are connected in series. In addition, the AC sides of the fourth AC / DC converters 14 of the plurality of converter cells are connected in series. As the number of stages of the converter cells connected in series increases, the AC voltage becomes multi-level. "(See paragraph 0019 of the specification).

特開２００５−７３３６２号公報Japanese Unexamined Patent Publication No. 2005-733362

特許文献１に記載されたコンバータセルは、例えば、１次側または２次側のうち一方の交流電圧を直流電圧に変換し、この直流電圧を他方の交流電圧に変換するものである。ここで、直流電圧には１次側または２次側周波数で変動する脈流成分が重畳する。この脈流成分が大きければ、１次側または２次側の電圧変動が大きくなるという問題が生じる。そこで、脈流成分を抑制しようとすると、コンバータセルに含まれるコンデンサ等の部品を大型化せざるを得ず、その結果、電力変換装置やコンバータセルが大型化し高価になるという問題があった。
この発明は上述した事情に鑑みてなされたものであり、小型で安価に構成できる電力変換装置および電力変換装置の接続方法を提供することを目的とする。 The converter cell described in Patent Document 1 converts, for example, an AC voltage of one of the primary side and the secondary side into a DC voltage, and converts this DC voltage into the other AC voltage. Here, a pulsating current component that fluctuates on the primary side or secondary side frequency is superimposed on the DC voltage. If this pulsating current component is large, there arises a problem that the voltage fluctuation on the primary side or the secondary side becomes large. Therefore, in order to suppress the pulsating current component, there is no choice but to increase the size of components such as capacitors included in the converter cell, and as a result, there is a problem that the power conversion device and the converter cell become large and expensive.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power conversion device and a method of connecting the power conversion device, which can be configured compactly and inexpensively.

上記課題を解決するため本発明の電力変換装置にあっては、１次側系統と、Ｎ相（Ｎは３以上の自然数）の交流系統である２次側系統との間に接続され、各々が一対の１次側端子と、一対の２次側端子とを有する第１〜第３の電力変換セルを備え、前記第１〜第３の電力変換セルの前記１次側端子は直列接続されるとともに、前記１次側系統に接続され、前記第１の電力変換セルの前記２次側端子は２次側第１相に係る箇所に接続され、前記第２の電力変換セルの前記２次側端子は２次側第２相に係る箇所に接続され、前記第３の電力変換セルの前記２次側端子は２次側第３相に係る箇所に接続されていることを特徴とする。 In order to solve the above problems, in the power conversion device of the present invention, the primary side system and the secondary side system which is an N-phase (N is a natural number of 3 or more) AC system are connected to each other. Is provided with a first to third power conversion cell having a pair of primary side terminals and a pair of secondary side terminals, and the primary side terminals of the first to third power conversion cells are connected in series. At the same time, it is connected to the primary side system, the secondary side terminal of the first power conversion cell is connected to a portion related to the secondary side first phase, and the secondary side of the second power conversion cell is connected. The side terminal is connected to a portion related to the second phase on the secondary side, and the secondary terminal of the third power conversion cell is connected to a portion related to the third phase on the secondary side.

本発明によれば、電力変換装置を小型で安価に構成できる。 According to the present invention, the power conversion device can be configured in a small size and at low cost.

本発明の第１実施形態による電力変換装置の結線図である。It is a wiring diagram of the power conversion apparatus according to 1st Embodiment of this invention. コンバータセルのブロック図である。It is a block diagram of a converter cell. 比較例による電力変換装置の結線図である。It is a wiring diagram of the power conversion device by the comparative example. 本発明の第２実施形態による電力変換装置の結線図である。It is a wiring diagram of the power conversion apparatus according to the 2nd Embodiment of this invention. 本発明の第３実施形態による電力変換装置の結線図である。It is a wiring diagram of the power conversion apparatus according to the 3rd Embodiment of this invention. 本発明の第４実施形態による電力変換装置の結線図である。It is a wiring diagram of the power conversion apparatus according to 4th Embodiment of this invention. コンバータセルの変形例のブロック図である。It is a block diagram of the modification of a converter cell. （ａ）〜（ｃ）は、他の変形例に適用される高周波トランス周辺の回路図である。(A) to (c) are circuit diagrams around a high-frequency transformer applied to other modified examples.

［第１実施形態］
〈第１実施形態の構成〉
まず、本発明の第１実施形態による電力変換装置１００の構成を説明する。
図１は、電力変換装置１００の結線図である。図示のように、電力変換装置１００は、１８台のコンバータセル２０−１〜２０−１８を有している。そして、コンバータセル２０−１は、１次側回路２１と、２次側回路２２と、高周波トランス１５と、を有している。コンバータセル２０−２〜２０−１８の構成も、コンバータセル２０−１のものと同様である。以下、コンバータセル２０−１〜２０−１８を総称して「コンバータセル２０」と表記することがある。 [First Embodiment]
<Structure of the first embodiment>
First, the configuration of the power conversion device 100 according to the first embodiment of the present invention will be described.
FIG. 1 is a wiring diagram of the power conversion device 100. As shown in the figure, the power converter 100 has 18 converter cells 20-1 to 20-18. The converter cell 20-1 has a primary side circuit 21, a secondary side circuit 22, and a high frequency transformer 15. The configurations of the converter cells 20-2 to 20-18 are the same as those of the converter cells 20-1. Hereinafter, the converter cells 20-1 to 20-18 may be collectively referred to as "converter cell 20".

電力変換装置１００は、何れも３相交流系統である１次側系統６０と、２次側系統７０との間で、双方向または一方向の電力変換を行うものである。ここで、１次側系統６０は、中性線６０Ｎと、Ｒ相、Ｓ相、Ｔ相電圧が現れるＲ相線６０Ｒ、Ｓ相線６０Ｓ、Ｔ相線６０Ｔと、を有している。また、２次側系統７０は、中性線７０Ｎと、Ｕ相、Ｖ相、Ｗ相電圧が現れるＵ相線７０Ｕ、Ｖ相線７０Ｖ、Ｗ相線７０Ｗと、を有している。 The power conversion device 100 performs bidirectional or unidirectional power conversion between the primary side system 60, which is a three-phase AC system, and the secondary side system 70. Here, the primary side system 60 has a neutral wire 60N and an R-phase wire 60R, an S-phase wire 60S, and a T-phase wire 60T in which R-phase, S-phase, and T-phase voltages appear. Further, the secondary side system 70 has a neutral wire 70N and a U-phase wire 70U, a V-phase wire 70V, and a W-phase wire 70W in which U-phase, V-phase, and W-phase voltages appear.

また、１次側系統６０と２次側系統７０とは、電圧振幅、周波数および位相が相互に独立している。そして、Ｒ相、Ｓ相、Ｔ相電圧は、１次側周波数において相互に「２π／３」の位相差を有し、Ｕ相、Ｖ相、Ｗ相電圧は、２次側周波数において相互に「２π／３」の位相差を有する。１次側，２次側系統６０，７０としては、例えば商用電源系統、太陽光発電システム、モータ等、様々な発電設備や受電設備を採用することができる。 Further, the primary side system 60 and the secondary side system 70 are independent of each other in voltage amplitude, frequency and phase. The R-phase, S-phase, and T-phase voltages have a phase difference of "2π / 3" with each other at the primary frequency, and the U-phase, V-phase, and W-phase voltages have a mutual phase difference at the secondary frequency. It has a phase difference of "2π / 3". As the primary side and secondary side systems 60 and 70, various power generation facilities and power receiving facilities such as a commercial power generation system, a photovoltaic power generation system, and a motor can be adopted.

図２は、コンバータセル２０のブロック図である。
上述した１次側回路２１は、交直変換器１１，１２と、コンデンサ１７とを有している。また、２次側回路２２は、交直変換器１３，１４と、コンデンサ１８とを有している。交直変換器１１〜１４は、各々Ｈブリッジ状に接続された４個のスイッチング素子と、これらスイッチング素子に逆並列に接続されたＦＷＤ（Free Wheeling Diode）とを有している（共に符号なし）。なお、本実施形態において、これらスイッチング素子は、例えばＭＯＳＦＥＴ（Metal-Oxide-Semiconductor Field-Effect Transistor）である。コンデンサ１７の両端の間に現れる電圧を１次側ＤＣリンク電圧Ｖdc1（１次側直流電圧）と呼ぶ。また、１次側端子２５，２６の間に現れる電圧を１次側ＡＣ端子間電圧Ｖ1と呼ぶ。そして、交直変換器１１は、１次側ＡＣ端子間電圧Ｖ1と、１次側ＤＣリンク電圧Ｖdc1とを双方向または一方向に変換しつつ電力を伝送する。 FIG. 2 is a block diagram of the converter cell 20.
The primary side circuit 21 described above includes AC / DC converters 11 and 12 and a capacitor 17. Further, the secondary side circuit 22 has AC / DC converters 13 and 14 and a capacitor 18. The AC / DC converters 11 to 14 each have four switching elements connected in an H-bridge shape and an FWD (Free Wheeling Diode) connected to these switching elements in antiparallel (both unsigned). .. In this embodiment, these switching elements are, for example, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). The voltage that appears between both ends of the capacitor 17 is called the primary side DC link voltage Vdc1 (primary side DC voltage). The voltage that appears between the primary side terminals 25 and 26 is called the primary side AC terminal voltage V1. Then, the AC / DC converter 11 transmits power while converting the voltage V1 between the AC terminals on the primary side and the DC link voltage Vdc1 on the primary side in both directions or in one direction.

高周波トランス１５は、１次巻線１５ａと、２次巻線１５ｂとを有し、１次巻線１５ａと２次巻線１５ｂとの間で、所定の周波数で電力を伝送する。交直変換器１２および１３が高周波トランス１５との間で入出力する電流は、高周波である。ここで、高周波とは、例えば１００Ｈｚ以上の周波数であるが、１ｋＨｚ以上の周波数を採用することが好ましく、１０ｋＨｚ以上の周波数を採用することがより好ましい。交直変換器１２は、１次側ＤＣリンク電圧Ｖdc1と、１次巻線１５ａに現れる電圧とを双方向または一方向に変換しつつ電力を伝送する。 The high-frequency transformer 15 has a primary winding 15a and a secondary winding 15b, and transmits electric power between the primary winding 15a and the secondary winding 15b at a predetermined frequency. The current input / output by the AC / DC converters 12 and 13 to / from the high frequency transformer 15 is high frequency. Here, the high frequency is, for example, a frequency of 100 Hz or higher, but it is preferable to adopt a frequency of 1 kHz or higher, and it is more preferable to adopt a frequency of 10 kHz or higher. The AC / DC converter 12 transmits power while converting the primary side DC link voltage Vdc1 and the voltage appearing in the primary winding 15a in both directions or in one direction.

また、コンデンサ１８の両端の間に現れる電圧を２次側ＤＣリンク電圧Ｖdc2（２次側直流電圧）と呼ぶ。交直変換器１３は、２次側ＤＣリンク電圧Ｖdc2と、２次巻線１５ｂに現れる電圧とを双方向または一方向に変換しつつ電力を伝送する。また、２次側端子２７，２８の間に現れる電圧を２次側ＡＣ端子間電圧Ｖ2と呼ぶ。そして、交直変換器１４は、２次側ＡＣ端子間電圧Ｖ2と、２次側ＤＣリンク電圧Ｖdc2とを双方向または一方向に変換しつつ電力を伝送する。 Further, the voltage appearing between both ends of the capacitor 18 is called a secondary side DC link voltage Vdc2 (secondary side DC voltage). The AC / DC converter 13 transmits power while converting the secondary side DC link voltage Vdc2 and the voltage appearing in the secondary winding 15b in both directions or in one direction. The voltage that appears between the secondary side terminals 27 and 28 is called the secondary side AC terminal voltage V2. Then, the AC / DC converter 14 transmits power while converting the secondary side AC terminal voltage V2 and the secondary side DC link voltage Vdc2 in both directions or in one direction.

図１に戻り、コンバータセル２０−１の１次側端子２５，２６および２次側端子２７，２８は図示するが、他のコンバータセル２０−２〜２０−１８のものについては、図示を省略する。コンバータセル２０−１〜２０−６の１次側端子２５，２６は、Ｒ相線６０Ｒと中性線６０Ｎとの間に、順次直列に接続されている。同様に、コンバータセル２０−７〜２０−１２の１次側端子２５，２６は、Ｔ相線６０Ｔと中性線６０Ｎとの間に、順次直列に接続されている。同様に、コンバータセル２０−１３〜２０−１８の１次側端子２５，２６は、Ｓ相線６０Ｓと中性線６０Ｎとの間に、順次直列に接続されている。 Returning to FIG. 1, the primary side terminals 25 and 26 and the secondary side terminals 27 and 28 of the converter cells 20-1 are shown, but the other converter cells 20-2 to 20-18 are not shown. do. The primary side terminals 25 and 26 of the converter cells 20-1 to 20-6 are sequentially connected in series between the R phase wire 60R and the neutral wire 60N. Similarly, the primary side terminals 25 and 26 of the converter cells 20-7 to 20-12 are sequentially connected in series between the T-phase wire 60T and the neutral wire 60N. Similarly, the primary side terminals 25 and 26 of the converter cells 20-13 to 20-18 are sequentially connected in series between the S phase wire 60S and the neutral wire 60N.

図１において、２次側回路２２のうち、Ｕ相線７０Ｕと中性線７０Ｎとの間に接続されているものにはドット網掛けを付している。すなわち、Ｕ相線７０Ｕと中性線７０Ｎとの間には、コンバータセル２０−１７，１０−１８（第９の電力変換セル）と、２０−３，２０−４（第２の電力変換セル）と、２０−７，２０−８（第４の電力変換セル）と、が直列に接続されている。 In FIG. 1, among the secondary side circuits 22, those connected between the U-phase wire 70U and the neutral wire 70N are shaded with dots. That is, between the U-phase line 70U and the neutral line 70N, converter cells 20-17, 10-18 (9th power conversion cell) and 20-3, 20-4 (second power conversion cell) ) And 20-7, 20-8 (fourth power conversion cell) are connected in series.

また、２次側回路２２のうち、Ｖ相線７０Ｖと中性線７０Ｎとの間に接続されているものにはハッチングを付している。すなわち、Ｖ相線７０Ｖと中性線７０Ｎとの間には、コンバータセル２０−１１，２０−１２（第６の電力変換セル）と、２０−１５，２０−１６（第８の電力変換セル）と、２０−１，２０−２（第１の電力変換セル）と、が直列に接続されている。 Further, among the secondary side circuits 22, those connected between the V-phase wire 70V and the neutral wire 70N are hatched. That is, between the V-phase line 70V and the neutral line 70N, the converter cells 20-11, 20-12 (sixth power conversion cell) and 20-15, 20-16 (eighth power conversion cell) ) And 20-1, 20-2 (first power conversion cell) are connected in series.

また、２次側回路２２のうち、Ｗ相線７０Ｗと中性線７０Ｎとの間に接続されているものは白ヌキになっている。すなわち、Ｗ相線７０Ｗと中性線７０Ｎとの間には、コンバータセル２０−５，２０−６（第３の電力変換セル）と、２０−９，２０−１０（第５の電力変換セル）と、コンバータセル２０−１３，２０−１４（第７の電力変換セル）と、が直列に接続されている。このように、電力変換装置１００は、１次側系統６０と２次側系統７０とをＹ−Ｙ結線にて接続するものである。 Further, among the secondary side circuits 22, those connected between the W phase line 70W and the neutral line 70N are white blank. That is, between the W phase line 70W and the neutral line 70N, converter cells 20-5, 20-6 (third power conversion cell) and 20-9, 20-10 (fifth power conversion cell) ) And the converter cells 20-13, 20-14 (seventh power conversion cell) are connected in series. In this way, the power conversion device 100 connects the primary side system 60 and the secondary side system 70 with a YY connection.

〈第１実施形態の動作〉
次に、再び図２を参照し、コンバータセル２０−１の動作を説明する。
図２に示すコンバータセル２０が図１におけるコンバータセル２０−１であった場合、１次側ＡＣ端子間電圧Ｖ1は、１次側のＲ相電圧を分圧した電圧になり、２次側ＡＣ端子間電圧Ｖ2は、２次側のＶ相電圧を分圧した電圧になる。電力潮流が１次側から２次側に向かって流れているとすると、１次側ＡＣ端子間電圧Ｖ1は、交直変換器１１によって整流され、コンデンサ１７によって平滑化される。すなわち、コンデンサ１７の両端には、平滑化された１次側ＤＣリンク電圧Ｖdc1が現れる。 <Operation of the first embodiment>
Next, the operation of the converter cell 20-1 will be described with reference to FIG. 2 again.
When the converter cell 20 shown in FIG. 2 is the converter cell 20-1 in FIG. 1, the voltage V1 between the primary side AC terminals becomes a voltage obtained by dividing the R phase voltage on the primary side, and the secondary side AC. The terminal voltage V2 is a voltage obtained by dividing the V-phase voltage on the secondary side. Assuming that the power flow is flowing from the primary side to the secondary side, the voltage V1 between the AC terminals on the primary side is rectified by the AC / DC converter 11 and smoothed by the capacitor 17. That is, a smoothed primary DC link voltage Vdc1 appears across the capacitor 17.

しかし、１次側ＤＣリンク電圧Ｖdc1は完全な直流ではなく、１次側周波数の脈流成分、すなわちＲ相電圧に同期する脈流成分を有している。交直変換器１２は、１次側ＤＣリンク電圧Ｖdc1を高周波で変調し、変調波は高周波トランス１５を介して交直変換器１３にて整流される。コンデンサ１８は、整流された電力によって充電され、その両端には２次側ＤＣリンク電圧Ｖdc2が現れる。この２次側ＤＣリンク電圧Ｖdc2も、１次側周波数の脈流成分、すなわちＲ相電圧に同期する脈流成分を有している。交直変換器１４は、脈流成分を含む２次側ＤＣリンク電圧Ｖdc2をスイッチングし、２次側周波数で交番する２次側ＡＣ端子間電圧Ｖ2を出力する。 However, the primary side DC link voltage Vdc1 is not a perfect direct current, but has a pulsating component of the primary side frequency, that is, a pulsating component synchronized with the R phase voltage. The AC / DC converter 12 modulates the primary side DC link voltage Vdc1 at a high frequency, and the modulated wave is rectified by the AC / DC converter 13 via a high frequency transformer 15. The capacitor 18 is charged by the rectified electric power, and the secondary side DC link voltage Vdc2 appears at both ends thereof. This secondary side DC link voltage Vdc2 also has a pulsating current component of the primary side frequency, that is, a pulsating current component synchronized with the R phase voltage. The AC / DC converter 14 switches the secondary side DC link voltage Vdc2 including the pulsating current component, and outputs the secondary side AC terminal voltage V2 that alternates at the secondary side frequency.

これにより、２次側ＡＣ端子間電圧Ｖ2は、１次側周波数で脈動する変動成分を含むことになる。そして、コンデンサ１７，１８の容量が小さいほど、この変動成分が大きくなる。コンデンサ１７，１８の容量を大きくすると、この変動成分を抑制できるが、これによってコンバータセル２０が大型化し、高価になるという問題が生じる。 As a result, the voltage V2 between the secondary AC terminals includes a fluctuating component that pulsates at the primary frequency. The smaller the capacitances of the capacitors 17 and 18, the larger this fluctuation component. By increasing the capacitances of the capacitors 17 and 18, this variable component can be suppressed, but this causes a problem that the converter cell 20 becomes large and expensive.

図１に戻り、Ｖ相に係るコンバータセル、すなわち２次側回路２２にハッチングを付したコンバータセル２０−１，２０−２，２０−１１，２０−１２，２０−１５，２０−１６の各２次側端子２７，２８に現れる２次側電圧は、何れも１次側周波数で脈動する変動成分を含んでいる。ここで、コンバータセル２０−１，２０−２の２次側電圧に現れる変動成分は、１次側Ｒ相電圧に同期する。また、コンバータセル２０−１１，２０−１２の２次側電圧に現れる変動成分は、１次側Ｔ相電圧に同期する。また、コンバータセル２０−１５，２０−１６の２次側電圧に現れる変動成分は、１次側Ｓ相電圧に同期する。 Returning to FIG. 1, each of the converter cells related to the V phase, that is, the converter cells 20-1, 20-2, 20-11, 20-12, 20-15, 20-16 with hatches on the secondary circuit 22 The secondary side voltages appearing at the secondary side terminals 27 and 28 all contain a fluctuating component that pulsates at the primary side frequency. Here, the variable component appearing in the secondary side voltage of the converter cells 20-1 and 20-2 is synchronized with the primary side R phase voltage. Further, the variable component appearing in the secondary side voltage of the converter cells 20-11 and 20-12 is synchronized with the primary side T-phase voltage. Further, the variable component appearing in the secondary side voltage of the converter cells 20-15 and 20-16 is synchronized with the primary side S-phase voltage.

これらＲ相電圧、Ｓ相電圧、Ｔ相電圧に同期する個々の変動成分は、略同一形状の波形であり、相互に「２π／３」の位相差を有する。これらＶ相に係る６台のコンバータセルが直列接続されると、Ｖ相電圧においてＲ相電圧、Ｓ相電圧、Ｔ相電圧に同期する個々の変動成分は相殺され、そのレベルは抑制される。これにより、個々のコンバータセルにおける２次側電圧の電圧変動率と比較して、Ｖ相電圧の電圧変動率を低くすることができる。以上Ｖ相電圧について説明したが、Ｕ相電圧およびＷ相電圧についても同様に、個々のコンバータセルよりも電圧変動率を低くすることができる。また、１次側のＲ相電圧、Ｓ相電圧およびＴ相電圧についても同様に、電圧変動率を低くすることができる。 The individual fluctuation components synchronized with the R-phase voltage, the S-phase voltage, and the T-phase voltage have substantially the same waveform and have a phase difference of "2π / 3" from each other. When the six converter cells related to the V phase are connected in series, the individual variable components synchronized with the R phase voltage, the S phase voltage, and the T phase voltage in the V phase voltage are canceled out, and the level thereof is suppressed. As a result, the voltage fluctuation rate of the V-phase voltage can be lowered as compared with the voltage fluctuation rate of the secondary side voltage in each converter cell. Although the V-phase voltage has been described above, the voltage fluctuation rate of the U-phase voltage and the W-phase voltage can also be made lower than that of the individual converter cells. Similarly, the voltage fluctuation rate can be lowered for the R-phase voltage, the S-phase voltage, and the T-phase voltage on the primary side.

このように、本実施形態によれば、コンデンサ１７，１８の容量が小さい場合であっても、１次側電圧および２次側電圧の電圧変動率を抑制できるため、コンデンサ１７，１８として容量の小さなものを適用することができ、小型かつ安価な電力変換装置１００を実現できる。 As described above, according to the present embodiment, even when the capacities of the capacitors 17 and 18 are small, the voltage fluctuation rates of the primary side voltage and the secondary side voltage can be suppressed. A small one can be applied, and a small and inexpensive power conversion device 100 can be realized.

ここで、各コンバータセル２０の１次側および２次側電位について検討する。まず、中性線６０Ｎの電位を１次側基準電位と呼び、中性線７０Ｎの電位を２次側基準電位と呼ぶ。１次側および２次側基準電位は、例えば接地電位であるが、必ずしも接地電位でなくてもよい。以下、各コンバータセル２０の１次側および２次側電位について検討するが、これらは、何れも１次側および２次側基準電位を基準とした電位である。 Here, the primary side and secondary side potentials of each converter cell 20 will be examined. First, the potential of the neutral wire 60N is called the primary side reference potential, and the potential of the neutral wire 70N is called the secondary side reference potential. The primary side and secondary side reference potentials are, for example, ground potentials, but they do not necessarily have to be ground potentials. Hereinafter, the primary side and secondary side potentials of each converter cell 20 will be examined, and these are all potentials based on the primary side and secondary side reference potentials.

図１において、各コンバータセル２０の、１次側基準電位（中性線６０Ｎの電位）に対する１次側回路２１の電位（絶対値）を「１次側電位」と呼ぶ。また、２次側基準電位（中性線７０Ｎの電位）に対する２次側回路２２の電位（絶対値）を「２次側電位」と呼ぶ。１次側電位は、中性線６０Ｎから離れるほど（Ｒ相線６０Ｒ、Ｓ相線６０Ｓ、Ｔ相線６０Ｔに近づくほど）高くなる。同様に、２次側電位は、中性線７０Ｎから離れるほど（Ｕ相線７０Ｕ、Ｖ相線７０Ｖ、Ｗ相線７０Ｗに近づくほど）高くなる。 In FIG. 1, the potential (absolute value) of the primary side circuit 21 with respect to the primary side reference potential (potential of the neutral line 60N) of each converter cell 20 is referred to as “primary side potential”. Further, the potential (absolute value) of the secondary side circuit 22 with respect to the secondary side reference potential (potential of the neutral wire 70N) is referred to as "secondary side potential". The primary potential increases as the distance from the neutral line 60N increases (as it approaches the R phase line 60R, the S phase line 60S, and the T phase line 60T). Similarly, the secondary potential increases as the distance from the neutral line 70N increases (the closer the U-phase line 70U, the V-phase line 70V, and the W-phase line 70W are).

例えば、２次側回路２２にハッチングを付したＶ相に係るコンバータセルについて、検討すると、これらの１次側電位は、２０−１２，２０−１１，２０−１６，２０−１５，２０−２，２０−１の順に高くなる。また、これらの２次側電位は、２０−１，２０−２，２０−１６，２０−１５，２０−１１，２０−１２の順に高くなる。このように、１次側電位の高いコンバータセル２０ほど２次側電圧は低くなる傾向を有している。これは、Ｕ相およびＷ相に係るコンバータセル２０についても同様である。 For example, when examining converter cells related to the V phase in which the secondary side circuit 22 is hatched, these primary side potentials are 20-12, 20-11, 20-16, 20-15, 20-2. , 20-1. Further, these secondary potentials increase in the order of 20-1, 20-2, 20-16, 20-15, 20-11, 20-12. As described above, the converter cell 20 having a higher primary potential tends to have a lower secondary voltage. This also applies to the converter cell 20 related to the U phase and the W phase.

高周波トランス１５（図２参照）の１次巻線１５ａと２次巻線１５ｂとの間の電圧を「トランス電位差」と呼ぶ。本実施形態によれば、各コンバータセル２０のトランス電位差を均等化でき、トランス電位差の最大値を比較的低くすることができる。これにより、高周波トランス１５の耐圧を下げることができ、高周波トランス１５として、小型かつ安価なものを適用することができ、電力変換装置１００を一層小型かつ安価に構成することができる。 The voltage between the primary winding 15a and the secondary winding 15b of the high frequency transformer 15 (see FIG. 2) is referred to as a "transformer potential difference". According to this embodiment, the transformer potential difference of each converter cell 20 can be equalized, and the maximum value of the transformer potential difference can be made relatively low. As a result, the withstand voltage of the high-frequency transformer 15 can be lowered, a small and inexpensive high-frequency transformer can be applied, and the power conversion device 100 can be configured more compactly and inexpensively.

〈比較例〉
次に、本実施形態の効果を明らかにするため、比較例の構成を説明する。
図３は、比較例における電力変換装置の結線図である。本比較例の電力変換装置１０１は、Ｐ台のコンバータセル２０−１〜２０−Ｐを有している。各コンバータセル２０の構成は第１実施形態のもの（図２参照）と同様である。本比較例において、コンバータセル２０−１〜２０−Ｐの１次側端子２５，２６（図２参照）は、１次側のＲ相線６０Ｒと中性線６０Ｎとの間に順次直列に接続されている。また、２次側端子２７，２８（図２参照）は、２次側のＵ相線７０Ｕと中性線７０Ｎとの間に順次直列に接続されている。１次側Ｓ相、Ｔ相および２次側Ｖ相、Ｗ相については図示を省略するが、１次側Ｒ相と同様に電力変換装置１０１が接続されている。 <Comparison example>
Next, in order to clarify the effect of the present embodiment, the configuration of the comparative example will be described.
FIG. 3 is a wiring diagram of the power conversion device in the comparative example. The power conversion device 101 of this comparative example has P converter cells 20-1 to 20-P. The configuration of each converter cell 20 is the same as that of the first embodiment (see FIG. 2). In this comparative example, the primary side terminals 25 and 26 (see FIG. 2) of the converter cells 20-1 to 20-P are sequentially connected in series between the primary side R phase wire 60R and the neutral wire 60N. Has been done. Further, the secondary side terminals 27 and 28 (see FIG. 2) are sequentially connected in series between the secondary side U-phase wire 70U and the neutral wire 70N. Although not shown, the primary side S phase, T phase, secondary side V phase, and W phase are not shown, but the power conversion device 101 is connected in the same manner as the primary side R phase.

本比較例においては、１次側のＲ相に係るコンバータセル２０−１〜２０−Ｐは、全てが２次側のＵ相に係るコンバータセルになる。第１実施形態と同様に、コンバータセル２０内のコンデンサ１７の両端に現れる１次側ＤＣリンク電圧Ｖdc1には、Ｒ相電圧に同期する脈流成分が発生する。従って、個々のコンバータセルにおける２次側電圧の電圧変動率と、Ｕ相電圧の電圧変動率とは同等の値になる。Ｖ相電圧およびＷ相電圧についても同様である。従って、本比較例は、２次側電圧の電圧変動率を抑制するために、コンデンサ１７，１８（図２参照）の容量を大きくせざるを得ず、第１実施形態と比較すると、電力変換装置１０１が大型化し、高価になる。 In this comparative example, all the converter cells 20-1 to 20-P related to the R phase on the primary side are converter cells related to the U phase on the secondary side. Similar to the first embodiment, a pulsating current component synchronized with the R phase voltage is generated in the primary side DC link voltage Vdc1 appearing at both ends of the capacitor 17 in the converter cell 20. Therefore, the voltage fluctuation rate of the secondary side voltage in each converter cell and the voltage fluctuation rate of the U-phase voltage are equivalent values. The same applies to the V-phase voltage and the W-phase voltage. Therefore, in this comparative example, in order to suppress the voltage fluctuation rate of the secondary side voltage, the capacities of the capacitors 17 and 18 (see FIG. 2) have to be increased, and compared with the first embodiment, the power conversion The device 101 becomes large and expensive.

また、本比較例において、１次側電圧Ｅ１が正のピーク値になり、２次側電圧Ｅ２が負のピーク値になった場合、または、１次側電圧Ｅ１が負のピーク値になり、２次側電圧Ｅ２が正のピーク値になった場合に、コンバータセル２０−１のトランス電位差が最大になる。すなわち、コンバータセル２０−１のトランス電位差は、１次側電圧Ｅ１および２次側電圧Ｅ２の振幅値の合計にほぼ等しくなり、第１実施形態のものよりも高くなる。逆に、コンバータセル２０−Ｐのトランス電位差は、１次側電圧Ｅ１および２次側電圧Ｅ２の振幅値の合計の「１／Ｐ」にほぼ等しくなり、第１実施形態のものよりも低くすることができる。 Further, in this comparative example, when the primary side voltage E1 becomes a positive peak value and the secondary side voltage E2 becomes a negative peak value, or when the primary side voltage E1 becomes a negative peak value, When the secondary side voltage E2 reaches a positive peak value, the transformer potential difference of the converter cell 20-1 becomes maximum. That is, the transformer potential difference of the converter cell 20-1 is substantially equal to the sum of the amplitude values of the primary side voltage E1 and the secondary side voltage E2, and is higher than that of the first embodiment. On the contrary, the transformer potential difference of the converter cell 20-P is substantially equal to "1 / P" of the sum of the amplitude values of the primary side voltage E1 and the secondary side voltage E2, which is lower than that of the first embodiment. be able to.

しかし、コンバータセル２０−１〜２０−Ｐとして同一仕様のものを適用しようとすると、トランス電位差が最も高いものに合わせて仕様を決定しなければならない。これにより、本比較例のコンバータセル２０は、第１実施形態のものと比較すると、高周波トランス１５として耐圧の高いものを適用せざるを得ず、これによって高周波トランス１５および電力変換装置１０１が一層大型化し、高価になる。 However, when trying to apply the converter cells 20-1 to 20-P having the same specifications, the specifications must be determined according to the one having the highest transformer potential difference. As a result, the converter cell 20 of this comparative example has no choice but to apply a high-frequency transformer 15 having a high withstand voltage as compared with that of the first embodiment, whereby the high-frequency transformer 15 and the power conversion device 101 are further subjected to. It becomes large and expensive.

〈第１実施形態の効果〉
以上のように、本実施形態によれば、１次側系統（６０）と、Ｎ相（Ｎは３以上の自然数）の交流系統である２次側系統（７０）との間に接続され、各々が一対の１次側端子（２５，２６）と、一対の２次側端子（２７，２８）とを有する第１〜第３の電力変換セル（２０−１〜２０−６）を備え、第１〜第３の電力変換セル（２０−１〜２０−６）の１次側端子は直列接続されるとともに、１次側系統（６０）に接続され、第１の電力変換セル（２０−１，２０−２）の２次側端子は２次側第１相（２次側Ｖ相）に係る箇所に接続され、第２の電力変換セル（２０−３，２０−４）の２次側端子は２次側第２相（２次側Ｕ相）に係る箇所に接続され、第３の電力変換セル（２０−５，２０−６）の２次側端子は２次側第３相（２次側Ｗ相）に係る箇所に接続されている。これにより、１次側電圧に基づく２次側電圧の変動成分、または２次側電圧に基づく１次側電圧の変動成分を小型の部品で抑制することができ、電力変換装置（１００）を小型かつ安価に構成できる。 <Effect of the first embodiment>
As described above, according to the present embodiment, it is connected between the primary side system (60) and the secondary side system (70) which is an AC system of N phase (N is a natural number of 3 or more). Each includes first to third power conversion cells (20-1 to 20-6) having a pair of primary terminals (25, 26) and a pair of secondary terminals (27, 28). The primary terminals of the first to third power conversion cells (20-1 to 20-6) are connected in series and connected to the primary system (60), so that the first power conversion cell (20-) is connected. The secondary terminal of 1,20-2) is connected to the location related to the secondary first phase (secondary V phase), and is the secondary of the second power conversion cell (20-3, 20-4). The side terminals are connected to the locations related to the secondary side second phase (secondary side U phase), and the secondary side terminals of the third power conversion cell (20-5, 20-6) are the secondary side third phase. It is connected to the location related to (secondary W phase). As a result, the fluctuation component of the secondary side voltage based on the primary side voltage or the fluctuation component of the primary side voltage based on the secondary side voltage can be suppressed by a small component, and the power conversion device (100) can be made small. And it can be configured inexpensively.

また、第１〜第３の電力変換セル（２０−１〜２０−６）は、それぞれ、１次巻線（１５ａ）と、１次巻線（１５ａ）に対して絶縁された２次巻線（１５ｂ）とを有するトランス（１５）を備える。これにより、１次側と２次側とを適切に絶縁できる。 Further, the first to third power conversion cells (20-1 to 20-6) are the primary winding (15a) and the secondary winding insulated from the primary winding (15a), respectively. A transformer (15) having (15b) is provided. Thereby, the primary side and the secondary side can be appropriately insulated.

また、本実施形態によれば、１次側系統（６０）は、Ｍ相（Ｍは３以上の自然数）の交流系統であり、電力変換装置（１００）は、各々が一対の１次側端子（２５，２６）と、一対の２次側端子（２７，２８）とを有する第４〜第９の電力変換セル（２０−７〜２０−１８）をさらに備え、第１〜第３の電力変換セル（２０−１〜２０−６）の１次側端子は直列接続されるとともに、１次側第１相（１次側Ｒ相）に係る箇所に接続され、第４〜第６の電力変換セル（２０−７〜２０−１２）の１次側端子は直列接続されるとともに、１次側第２相（１次側Ｔ相）に係る箇所に接続され、第７〜第９の電力変換セル（２０−１３〜２０−１８）の１次側端子は直列接続されるとともに、１次側第３相（１次側Ｓ相）に係る箇所に接続され、第１の電力変換セル（２０−１，２０−２）、第６の電力変換セル（２０−１１，２０−１２）、および第８の電力変換セル（２０−１５，２０−１６）の２次側端子は直列接続されるとともに、２次側第１相（２次側Ｖ相）に係る箇所に接続され、第２の電力変換セル（２０−３，２０−４）、第４の電力変換セル（２０−７，２０−８）、および第９の電力変換セル（２０−１７，１０−１８）の２次側端子は直列接続されるとともに、２次側第２相（２次側Ｕ相）に係る箇所に接続され、第３の電力変換セル（２０−５，２０−６）、第５の電力変換セル（２０−９，２０−１０）、および第７の電力変換セル（２０−１３，２０−１４）の２次側端子は直列接続されるとともに、２次側第３相（２次側Ｗ相）に係る箇所に接続されている。
これにより、多相交流同士を変換する場合においても、１次側電圧に基づく２次側電圧の変動成分、または２次側電圧に基づく１次側電圧の変動成分を小型の部品で抑制することができ、電力変換装置（１００）を小型で安価に構成できる。 Further, according to the present embodiment, the primary side system (60) is an AC system of M phase (M is a natural number of 3 or more), and the power conversion device (100) has a pair of primary side terminals. A fourth to ninth power conversion cell (20-7 to 20-18) having (25, 26) and a pair of secondary terminal (27, 28) is further provided, and the first to third power is provided. The primary side terminals of the conversion cells (20-1 to 20-6) are connected in series and are connected to the locations related to the primary side first phase (primary side R phase), and the fourth to sixth power sources are connected. The primary side terminals of the conversion cells (20-7 to 20-12) are connected in series and are connected to the locations related to the primary side second phase (primary side T phase), and the seventh to ninth power sources are connected. The primary side terminals of the conversion cells (20-13 to 20-18) are connected in series and are connected to the locations related to the primary side third phase (primary side S phase), and the first power conversion cell (1st power conversion cell (20-13 to 20-18)). The secondary terminals of 20-1, 20-2), the sixth power conversion cell (20-11, 20-12), and the eighth power conversion cell (20-15, 20-16) are connected in series. At the same time, it is connected to the location related to the first phase on the secondary side (V phase on the secondary side), and is connected to the second power conversion cell (20-3, 20-4) and the fourth power conversion cell (20-7, 20-8) and the secondary side terminals of the ninth power conversion cell (20-17, 10-18) are connected in series, and at the location related to the secondary side second phase (secondary side U phase). Connected, a third power conversion cell (20-5, 20-6), a fifth power conversion cell (20-9, 20-10), and a seventh power conversion cell (20-13, 20-14). ) Is connected in series and is connected to a portion related to the secondary side third phase (secondary side W phase).
As a result, even when converting multi-phase AC to each other, the fluctuation component of the secondary side voltage based on the primary side voltage or the fluctuation component of the primary side voltage based on the secondary side voltage can be suppressed by a small component. The power conversion device (100) can be configured in a small size and at low cost.

また、トランス（１５）は１次巻線（１５ａ）と２次巻線（１５ｂ）との間で１００Ｈｚ以上の周波数で電力を伝送するものであり、第１〜第３の電力変換セル（２０−１〜２０−６）は、それぞれ、１次側端子（２５，２６）と１次巻線（１５ａ）との間で電力を伝送する１次側回路（２１）と、２次側端子（２７，２８）と２次巻線（１５ｂ）との間で電力を伝送する２次側回路（２２）と、をさらに備える。これにより、１次側回路（２１）および２次側回路（２２）において、電力を適切に変換できる。 Further, the transformer (15) transmits electric power between the primary winding (15a) and the secondary winding (15b) at a frequency of 100 Hz or higher, and the first to third power conversion cells (20). -1 to 20-6) are the primary side circuit (21) and the secondary side terminal (21) that transmit power between the primary side terminals (25, 26) and the primary winding (15a), respectively. It further comprises a secondary circuit (22) that transmits power between the 27, 28) and the secondary winding (15b). Thereby, the electric power can be appropriately converted in the primary side circuit (21) and the secondary side circuit (22).

また、１次側回路（２１）は、一対の１次側端子（２５，２６）と１次側直流電圧（Ｖdc1）との間で電力を伝送する第１の交直変換器（１１）と、１次側直流電圧（Ｖdc1）と１次巻線（１５ａ）との間で電力を伝送する第２の交直変換器（１２）と、を有し、２次側回路（２２）は、２次側直流電圧（Ｖdc2）と２次巻線（１５ｂ）との間で電力を伝送する第３の交直変換器（１３）と、一対の２次側端子（２７，２８）と２次側直流電圧（Ｖdc2）との間で電力を伝送する第４の交直変換器（１４）と、を有する。これにより、直流電圧を介して、安定的に電力を変換できる。 Further, the primary side circuit (21) includes a first AC / DC converter (11) that transmits power between a pair of primary side terminals (25, 26) and a primary side DC voltage (Vdc1). It has a second AC / DC converter (12) that transmits power between the primary side DC voltage (Vdc1) and the primary winding (15a), and the secondary side circuit (22) is secondary. A third AC / DC converter (13) that transmits power between the side DC voltage (Vdc2) and the secondary winding (15b), a pair of secondary terminals (27, 28), and a secondary DC voltage. It has a fourth AC / DC converter (14) that transmits power to and from (Vdc2). As a result, electric power can be stably converted via the DC voltage.

また、本実施形態においては、第１〜第３の電力変換セル（２０−１〜２０−６）のうち、１次側端子（２５，２６）における対地電位の絶対値が最も高くなる電力変換セル（２０−１）と、２次側端子（２７，２８）における対地電位の絶対値が最も高くなる電力変換セル（２０−６）と、が異なり、第４〜第６の電力変換セル（２０−７〜２０−１２）のうち、１次側端子（２５，２６）における対地電位の絶対値が最も高くなる電力変換セル（２０−７）と、２次側端子（２７，２８）における対地電位の絶対値が最も高くなる電力変換セル（２０−１２）と、が異なり、第７〜第９の電力変換セル（２０−１３〜２０−１８）のうち、１次側端子（２５，２６）における対地電位の絶対値が最も高くなる電力変換セル（２０−１３）と、２次側端子（２７，２８）における対地電位の絶対値が最も高くなる電力変換セル（２０−１８）と、が異なるように、各々の２次側端子を２次側系統（７０）に接続している。
これにより、電力変換セルのトランス電位差のばらつきを小さくすることができ、耐圧の低いトランス（１５）を適用することができる。これにより、電力変換装置（１００）を一層小型かつ安価に構成できる。 Further, in the present embodiment, among the first to third power conversion cells (20-1 to 20-6), the power conversion in which the absolute value of the ground potential at the primary side terminals (25, 26) is the highest. The cell (20-1) and the power conversion cell (20-6) having the highest absolute value of the ground potential at the secondary terminal (27, 28) are different from each other, and the fourth to sixth power conversion cells ( 20-7 to 20-12), in the power conversion cell (20-7) where the absolute value of the ground potential at the primary side terminals (25, 26) is the highest, and at the secondary side terminals (27, 28). The primary terminal (25,) of the 7th to 9th power conversion cells (20-13 to 20-18) is different from the power conversion cell (20-12) having the highest absolute value to the ground potential. The power conversion cell (20-13) having the highest absolute value of the ground potential in 26) and the power conversion cell (20-18) having the highest absolute value of the ground potential in the secondary terminals (27, 28). , Are different, and each secondary terminal is connected to the secondary system (70).
As a result, the variation in the transformer potential difference of the power conversion cell can be reduced, and the transformer (15) having a low withstand voltage can be applied. As a result, the power conversion device (100) can be configured in a smaller size and at a lower cost.

［第２実施形態］
次に、本発明の第２実施形態による電力変換装置１２０の構成を説明する。なお、以下の説明において、図１〜図３の各部に対応する部分には同一の符号を付し、その説明を省略する場合がある。
図４は、電力変換装置１２０の結線図である。電力変換装置１２０は、第１実施形態のもの（図１参照）と同様に、１８台のコンバータセル２０−１〜２０−１８を有している。各コンバータセル２０の構成は第１実施形態のもの（図２参照）と同様である。電力変換装置１２０は、何れも３相交流系統である１次側系統６２と、２次側系統７０との間で、双方向または一方向の電力変換を行うものである。 [Second Embodiment]
Next, the configuration of the power conversion device 120 according to the second embodiment of the present invention will be described. In the following description, the parts corresponding to the respective parts of FIGS. 1 to 3 may be designated by the same reference numerals, and the description thereof may be omitted.
FIG. 4 is a wiring diagram of the power conversion device 120. The power conversion device 120 has 18 converter cells 20-1 to 20-18, as in the case of the first embodiment (see FIG. 1). The configuration of each converter cell 20 is the same as that of the first embodiment (see FIG. 2). The power conversion device 120 performs bidirectional or unidirectional power conversion between the primary side system 62, which is a three-phase AC system, and the secondary side system 70.

ここで、１次側系統６２は、Ｒ相、Ｓ相、Ｔ相電圧が現れるＲ相線６２Ｒ、Ｓ相線６２Ｓ、およびＴ相線６２Ｔを有している。また、２次側系統７０の構成は、第１実施形態のものと同様である。コンバータセル２０−１〜２０−６の１次側端子２５，２６（図２参照）は、Ｒ相線６２ＲとＴ相線６２Ｔとの間に、順次直列に接続されている。同様に、コンバータセル２０−７〜２０−１２の１次側端子２５，２６は、Ｔ相線６２ＴとＳ相線６２Ｓとの間に、順次直列に接続されている。同様に、コンバータセル２０−１３〜２０−１８の１次側端子２５，２６は、Ｓ相線６２ＳとＲ相線６２Ｒとの間に、順次直列に接続されている。 Here, the primary side system 62 has an R-phase wire 62R, an S-phase wire 62S, and a T-phase wire 62T in which R-phase, S-phase, and T-phase voltages appear. The configuration of the secondary side system 70 is the same as that of the first embodiment. The primary side terminals 25 and 26 (see FIG. 2) of the converter cells 20-1 to 20-6 are sequentially connected in series between the R-phase wire 62R and the T-phase wire 62T. Similarly, the primary side terminals 25 and 26 of the converter cells 20-7 to 20-12 are sequentially connected in series between the T-phase wire 62T and the S-phase wire 62S. Similarly, the primary side terminals 25 and 26 of the converter cells 20-13 to 20-18 are sequentially connected in series between the S phase wire 62S and the R phase wire 62R.

また、各コンバータセル２０の２次側端子２７，２８と、２次側系統７０との接続関係は、第１実施形態のものと同様である。このように、電力変換装置１２０は、１次側系統６２と２次側系統７０とをΔ−Ｙ結線にて接続するものである。本実施形態によれば、第１実施形態と同様の効果を奏するとともに、中性線の無い、３相３線式の１次側系統６２にも適用できる点で適用範囲を広げることができる。
なお、上述した例では、１次側をＹ結線とし、２次側をΔ結線にしたが、１次側をΔ結線とし、２次側をＹ結線にしてもよい。 Further, the connection relationship between the secondary side terminals 27 and 28 of each converter cell 20 and the secondary side system 70 is the same as that of the first embodiment. In this way, the power conversion device 120 connects the primary side system 62 and the secondary side system 70 with a Δ-Y connection. According to the present embodiment, the same effect as that of the first embodiment can be obtained, and the range of application can be expanded in that it can be applied to the primary side system 62 of the three-phase three-wire system having no neutral wire.
In the above-mentioned example, the primary side is Y-connected and the secondary side is Δ-connected, but the primary side may be Δ-connected and the secondary side may be Y-connected.

［第３実施形態］
次に、本発明の第３実施形態による電力変換装置１３０の構成を説明する。なお、以下の説明において、図１〜図４の各部に対応する部分には同一の符号を付し、その説明を省略する場合がある。
図５は、電力変換装置１３０の結線図である。電力変換装置１３０は、第２実施形態のもの（図４参照）と同様に、１８台のコンバータセル２０−１〜２０−１８を有している。各コンバータセル２０の構成は第１実施形態のもの（図２参照）と同様である。電力変換装置１３０は、何れも３相交流系統である１次側系統６２と、２次側系統７２との間で、双方向または一方向の電力変換を行うものである。 [Third Embodiment]
Next, the configuration of the power conversion device 130 according to the third embodiment of the present invention will be described. In the following description, the parts corresponding to the respective parts of FIGS. 1 to 4 may be designated by the same reference numerals, and the description thereof may be omitted.
FIG. 5 is a wiring diagram of the power conversion device 130. The power conversion device 130 has 18 converter cells 20-1 to 20-18, as in the case of the second embodiment (see FIG. 4). The configuration of each converter cell 20 is the same as that of the first embodiment (see FIG. 2). The power conversion device 130 performs bidirectional or unidirectional power conversion between the primary side system 62, which is a three-phase AC system, and the secondary side system 72.

ここで、１次側系統６２の構成は第２実施形態（図４参照）のものと同様である。また、コンバータセル２０−１〜２０−１８の１次側端子２５，２６と、１次側系統６２との接続関係も、第２実施形態のものと同様である。一方、２次側系統７２は、Ｕ相、Ｖ相、Ｗ相電圧が現れるＵ相線７２Ｕ、Ｖ相線７２ＶおよびＷ相線７２Ｗを有している。 Here, the configuration of the primary side system 62 is the same as that of the second embodiment (see FIG. 4). Further, the connection relationship between the primary side terminals 25 and 26 of the converter cells 20-1 to 20-18 and the primary side system 62 is the same as that of the second embodiment. On the other hand, the secondary side system 72 has a U-phase line 72U, a V-phase line 72V, and a W-phase line 72W in which U-phase, V-phase, and W-phase voltages appear.

ここで、２次側回路２２にハッチングを付したコンバータセル２０−１，２０−２，２０−１６，２０−１５，２０−１１，２０−１２の各２次側端子２７，２８は、Ｕ相線７２ＵとＶ相線７２Ｖとの間に順次直列に接続されている。また、２次側回路２２が白ヌキであるコンバータセル２０−１３，２０−１４，２０−１０，２０−９，２０−５，２０−６の各２次側端子２７，２８は、Ｖ相線７２ＶとＷ相線７２Ｗとの間に順次直列に接続されている。また、２次側回路２２にドット網掛けを付したコンバータセル２０−７，２０−８，２０−４，２０−３，２０−１７，２０−１８の各２次側端子２７，２８は、Ｗ相線７２ＷとＵ相線７２Ｕとの間に順次直列に接続されている。 Here, the secondary side terminals 27 and 28 of the converter cells 20-1, 20-2, 20-16, 20-15, 20-11, 20-12 having hatches on the secondary side circuit 22 are U. The phase wire 72U and the V phase wire 72V are sequentially connected in series. Further, the secondary side terminals 27 and 28 of the converter cells 20-13, 20-14, 20-10, 20-9, 20-5, 20-6 in which the secondary side circuit 22 is white are V-phase. The wire 72V and the W phase wire 72W are sequentially connected in series. Further, the secondary side terminals 27 and 28 of the converter cells 20-7, 20-8, 20-4, 20-3, 20-17 and 20-18 in which the secondary side circuit 22 is dotted-shaded are The W-phase wire 72W and the U-phase wire 72U are sequentially connected in series.

このように、電力変換装置１３０は、１次側系統６２と２次側系統７２をΔ−Δ結線にて接続するものである。本実施形態によれば、第１実施形態と同様の効果を奏するとともに、１次側系統６２および２次側系統７２が共に中性線の無い、３相３線式の系統であっても適用できる点で、適用範囲をさらに広げることができる。 In this way, the power conversion device 130 connects the primary side system 62 and the secondary side system 72 with a Δ−Δ connection. According to this embodiment, the same effect as that of the first embodiment is obtained, and it is applied even if both the primary side system 62 and the secondary side system 72 are a three-phase three-wire system having no neutral wire. Where possible, the scope of application can be further expanded.

［第４実施形態］
次に、本発明の第４実施形態による電力変換装置１４０の構成を説明する。なお、以下の説明において、図１〜図５の各部に対応する部分には同一の符号を付し、その説明を省略する場合がある。
図６は、電力変換装置１４０の結線図である。電力変換装置１４０は、３台のコンバータセル２０−１０１〜２０−１０３（第１〜第３の電力変換セル）を有している。各コンバータセル２０の構成は第１実施形態のもの（図２参照）と同様である。電力変換装置１４０は、単相交流系統である１次側系統６４と、３相交流系統である２次側系統７４との間で、双方向または一方向の電力変換を行うものである。 [Fourth Embodiment]
Next, the configuration of the power conversion device 140 according to the fourth embodiment of the present invention will be described. In the following description, the parts corresponding to the respective parts of FIGS. 1 to 5 may be designated by the same reference numerals, and the description thereof may be omitted.
FIG. 6 is a wiring diagram of the power conversion device 140. The power conversion device 140 has three converter cells 20-101 to 20-103 (first to third power conversion cells). The configuration of each converter cell 20 is the same as that of the first embodiment (see FIG. 2). The power conversion device 140 performs bidirectional or unidirectional power conversion between the primary side system 64, which is a single-phase AC system, and the secondary side system 74, which is a three-phase AC system.

ここで、１次側系統６４は、一対の線路６４Ｐ，６４Ｎを有している。また、２次側系統７４は、中性線７４Ｎと、Ｕ相、Ｖ相、Ｗ相電圧が現れるＵ相線７４Ｕ、Ｖ相線７４Ｖ、Ｗ相線７４Ｗと、を有している。コンバータセル２０−１０１〜２０−１０３の１次側端子２５，２６は、線路６４Ｐ，６４Ｎの間に順次直列に接続されている。 Here, the primary side system 64 has a pair of lines 64P and 64N. Further, the secondary side system 74 has a neutral wire 74N and a U-phase wire 74U, a V-phase wire 74V, and a W-phase wire 74W in which U-phase, V-phase, and W-phase voltages appear. The primary side terminals 25 and 26 of the converter cells 20-101 to 20-103 are sequentially connected in series between the lines 64P and 64N.

また、コンバータセル２０−１０１の２次側端子２７，２８は、それぞれＶ相線７４Ｖおよび中性線７４Ｎに接続されている。同様に、コンバータセル２０−１０２の２次側端子２７，２８は、それぞれＵ相線７４Ｕおよび中性線７４Ｎに接続されている。同様に、コンバータセル２０−１０３の２次側端子２７，２８は、それぞれＷ相線７４Ｗおよび中性線７４Ｎに接続されている。 Further, the secondary side terminals 27 and 28 of the converter cells 20-101 are connected to the V-phase wire 74V and the neutral wire 74N, respectively. Similarly, the secondary terminals 27 and 28 of the converter cells 20-102 are connected to the U-phase wire 74U and the neutral wire 74N, respectively. Similarly, the secondary terminals 27 and 28 of the converter cells 20-103 are connected to the W phase wire 74W and the neutral wire 74N, respectively.

図６において、電力潮流が２次側から１次側に向かって流れているとすると、コンバータセル２０−１０１に含まれるコンデンサ１７，１８（図２参照）の端子電圧には、Ｖ相電圧に同期する脈流成分を有している。これにより、コンバータセル２０−１０１の１次側電圧に現れる変動成分は、２次側Ｖ相電圧に同期する。同様に、コンバータセル２０−１０２の１次側電圧に現れる変動成分は、２次側Ｕ相電圧に同期する。同様に、コンバータセル２０−１０３の１次側電圧に現れる変動成分は、２次側Ｗ相電圧に同期する。 In FIG. 6, assuming that the power flow flows from the secondary side to the primary side, the terminal voltage of the capacitors 17 and 18 (see FIG. 2) included in the converter cells 20-101 is a V-phase voltage. It has a synchronous pulsating component. As a result, the variable component appearing in the primary side voltage of the converter cells 20-101 is synchronized with the secondary side V-phase voltage. Similarly, the variable component appearing in the primary side voltage of the converter cells 20-102 is synchronized with the secondary side U-phase voltage. Similarly, the variable component appearing in the primary side voltage of the converter cells 20-103 is synchronized with the secondary side W phase voltage.

これらＶ相電圧、Ｕ相電圧、Ｗ相電圧に同期する個々の変動成分は、略同一形状の波形であり、相互に「２π／３」の位相差を有する。これらコンバータセル２０−１０１〜２０−１０３の１次側端子２５，２６が直列接続されると、１次側電圧においてＶ相電圧、Ｕ相電圧、Ｗ相電圧に同期する個々の変動成分は相殺され、そのレベルは抑制される。 The individual fluctuation components synchronized with the V-phase voltage, the U-phase voltage, and the W-phase voltage have substantially the same waveform and have a phase difference of "2π / 3" from each other. When the primary side terminals 25 and 26 of these converter cells 20-101 to 20-103 are connected in series, the individual variable components synchronized with the V-phase voltage, U-phase voltage, and W-phase voltage at the primary side voltage cancel each other out. And its level is suppressed.

このように、本実施形態は、１次側系統（６４）と、Ｎ相（Ｎは３以上の自然数）の２次側系統（７４）との間に接続され、各々が一対の１次側端子（２５，２６）と、一対の２次側端子（２７，２８）とを有する第１〜第３の電力変換セル（２０−１０１〜２０−１０３）を備え、第１〜第３の電力変換セル（２０−１０１〜２０−１０３）の１次側端子は直列接続されるとともに、１次側系統（６４）に接続され、第１の電力変換セル（２０−１０１）の２次側端子は２次側第１相（２次側Ｖ相）に係る箇所に接続され、第２の電力変換セル（２０−１０２）の２次側端子は２次側第２相（２次側Ｕ相）に係る箇所に接続され、第３の電力変換セル（２０−１０３）の２次側端子は２次側第３相（２次側Ｗ相）に係る箇所に接続されている点で、第１〜第３実施形態と同様である。 In this way, the present embodiment is connected between the primary side system (64) and the secondary side system (74) of the N phase (N is a natural number of 3 or more), and each is a pair of primary sides. The first to third power conversion cells (20-101 to 20-103) having terminals (25, 26) and a pair of secondary side terminals (27, 28) are provided, and the first to third powers are provided. The primary terminal of the conversion cell (20-101 to 20-103) is connected in series and is connected to the primary system (64), and the secondary terminal of the first power conversion cell (20-101) is connected. Is connected to the location related to the secondary side first phase (secondary side V phase), and the secondary side terminal of the second power conversion cell (20-102) is the secondary side second phase (secondary side U phase). ), And the secondary terminal of the third power conversion cell (20-103) is connected to the secondary third phase (secondary W phase). This is the same as that of the first to third embodiments.

従って、本実施形態は、第１〜第３実施形態のものと同様に、コンデンサ１７，１８（図２参照）の容量が小さい場合であっても、電圧変動率を抑制できるため、コンデンサ１７，１８として容量の小さなものを適用することができ、小型かつ安価な電力変換装置１４０を実現できるという効果を奏する。 Therefore, in the present embodiment, as in the first to third embodiments, the voltage fluctuation rate can be suppressed even when the capacities of the capacitors 17 and 18 (see FIG. 2) are small. As the value 18, a device having a small capacity can be applied, and an effect that a small and inexpensive power conversion device 140 can be realized can be obtained.

［変形例］
本発明は上述した実施形態に限定されるものではなく、種々の変形が可能である。上述した実施形態は本発明を理解しやすく説明するために例示したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、ある実施形態の構成に他の実施形態の構成を加えることも可能である。また、各実施形態の構成の一部について削除し、もしくは他の構成の追加・置換をすることが可能である。また、図中に示した制御線や情報線は説明上必要と考えられるものを示しており、製品上で必要な全ての制御線や情報線を示しているとは限らない。実際には殆ど全ての構成が相互に接続されていると考えてもよい。上記実施形態に対して可能な変形は、例えば以下のようなものである。 [Modification example]
The present invention is not limited to the above-described embodiment, and various modifications are possible. The above-described embodiments are exemplified for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to delete a part of the configuration of each embodiment, or add / replace another configuration. In addition, the control lines and information lines shown in the figure show what is considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for the product. In practice, it can be considered that almost all configurations are interconnected. Possible modifications to the above embodiment are, for example, as follows.

（１）上記各実施形態においては、スイッチング素子としてＭＯＳＦＥＴを適用した例を説明したが、スイッチング素子として、ＩＧＢＴ（Insulated Gate Bipolar Transistor）、バイポーラトランジスタ、サイリスタ、ＧＴＯ（Gate Turn-Off Thyristor）、ＩＥＧＴ（Injection Enhanced Gate Transistor）、あるいはサイラトロン等の真空管式の素子を適用してもよい。また、半導体を適用する場合に、その材質はＳｉ、ＳｉＣ、ＧａＮ等、任意のものを適用できる。 (1) In each of the above embodiments, an example in which a MOSFET is applied as a switching element has been described, but the switching elements include an IGBT (Insulated Gate Bipolar Transistor), a bipolar transistor, a thyristor, a GTO (Gate Turn-Off Thyristor), and an IEGT. (Injection Enhanced Gate Transistor), or a vacuum tube type element such as a silatron may be applied. Further, when a semiconductor is applied, any material such as Si, SiC, and GaN can be applied as the material.

（２）図７は、コンバータセル２０の変形例のブロック図である。図２に示した交直変換器１１〜１４は、双方向に電力を変換できるようにスイッチング素子を用いたＨブリッジを適用したが、一方向に電力を変換できればよい場合は、交直変換器１１〜１４の一部において、整流素子を用いたＨブリッジを適用してもよい。図７に示す構成は、その一例として、図２における交直変換器１３を、４個の整流素子（符号なし）を適用した交直変換器１３ａに置換したものである。本変形例においても、高周波トランス１５のトランス電位差は、上記各実施形態と同様になるため、電力変換装置を小型かつ安価に構成することができる。交直変換器１３ａにおける４個の整流素子は、半導体ダイオードであってもよく、真空管式の水銀整流器等であってもよい。また、半導体を適用する場合に、その材質はＳｉ、ＳｉＣ、ＧａＮ等、任意のものを適用できる。 (2) FIG. 7 is a block diagram of a modified example of the converter cell 20. The AC / DC converters 11 to 14 shown in FIG. 2 apply an H-bridge using a switching element so that power can be converted in both directions. However, if it is sufficient to convert power in one direction, the AC / DC converters 11 to 14 are used. An H-bridge using a rectifying element may be applied to a part of 14. As an example, the configuration shown in FIG. 7 is obtained by replacing the AC / DC converter 13 in FIG. 2 with an AC / DC converter 13a to which four rectifying elements (unsigned) are applied. Also in this modification, the transformer potential difference of the high-frequency transformer 15 is the same as in each of the above embodiments, so that the power conversion device can be configured compactly and inexpensively. The four rectifying elements in the AC / DC converter 13a may be a semiconductor diode, a vacuum tube type mercury rectifier, or the like. Further, when a semiconductor is applied, any material such as Si, SiC, and GaN can be applied as the material.

（３）上述した第１実施形態においては、１次側電位の高いコンバータセル２０ほど２次側電圧は低くなる傾向を有するように、各コンバータセル２０−１〜２０−１８を接続した。より詳細には、１次側端子２５，２６における対地電位の絶対値が最も高くなるコンバータセル２０と、２次側端子２７，２８における対地電位の絶対値が最も高くなるコンバータセル２０セルと、が異なるように、各コンバータセル２０−１〜２０−１８を接続した。
しかし、高周波トランス１５が、高いトランス電位差に対応できる場合は、必ずしもこのような接続方法を採らなくてもよい。すなわち、１次側端子２５，２６における対地電位の絶対値が最も高くなるコンバータセル２０と、２次側端子２７，２８における対地電位の絶対値が最も高くなるコンバータセル２０とが同一のものであってもよい。 (3) In the first embodiment described above, the converter cells 20-1 to 20-18 are connected so that the converter cells 20 having a higher primary potential tend to have a lower secondary voltage. More specifically, the converter cell 20 having the highest absolute value of the ground potential at the primary terminals 25 and 26, and the converter cell 20 cell having the highest absolute value of the ground potential at the secondary terminals 27 and 28. Each converter cell 20-1 to 20-18 was connected so as to be different.
However, if the high-frequency transformer 15 can cope with a high transformer potential difference, it is not always necessary to adopt such a connection method. That is, the converter cell 20 having the highest absolute value of the ground potential at the primary terminals 25 and 26 and the converter cell 20 having the highest absolute value of the ground potential at the secondary terminals 27 and 28 are the same. There may be.

また、図１において、コンバータセル２０−１〜２０−６１次側電位の高い順に列挙すると、コンバータセル２０−１，２０−２（Ｖ相）、コンバータセル２０−３，２０−４（Ｕ相）、コンバータセル２０−５，２０−６（Ｗ相）、の順になっている。しかし、この順序は、高周波トランス１５が対応可能であれば、（Ｕ，Ｖ，Ｗ）、（Ｕ，Ｗ，Ｖ）、（Ｖ，Ｕ，Ｗ）、（Ｖ，Ｗ，Ｕ）、（Ｗ，Ｕ，Ｖ）、（Ｗ，Ｖ，Ｕ）の６通りの順序のうち何れであってもよい。 Further, in FIG. 1, when the converter cells 20-1 to 20-6 are listed in descending order of potential, the converter cells 20-1, 20-2 (V phase) and the converter cells 20-3, 20-4 (U phase) are listed in descending order. ), Converter cells 20-5, 20-6 (W phase), in that order. However, this order is (U, V, W), (U, W, V), (V, U, W), (V, W, U), (W) if the high frequency transformer 15 can handle it. , U, V), (W, V, U) may be in any of the six sequences.

（４）また、上記各実施形態において、図２に示す交直変換器１２，１３と、高周波トランス１５との間にコンデンサを挿入してもよい。図８（ａ）は、交直変換器１２と１次巻線１５ａとの間にコンデンサ５１を挿入するとともに、交直変換器１３と２次巻線１５ｂとの間にコンデンサ５２を挿入した例を示す。また、図８（ｂ）は、交直変換器１２と１次巻線１５ａとの間にコンデンサ５１を挿入した例であり、図８（ｃ）は、交直変換器１３と２次巻線１５ｂとの間にコンデンサ５２を挿入した例である。また、上記各実施形態に適用される高周波トランス１５は、意図的に漏れインダクタンスを発生させるように設計したものを用いてもよい。 (4) Further, in each of the above embodiments, a capacitor may be inserted between the AC / DC converters 12 and 13 shown in FIG. 2 and the high frequency transformer 15. FIG. 8A shows an example in which the capacitor 51 is inserted between the AC / DC converter 12 and the primary winding 15a, and the capacitor 52 is inserted between the AC / DC converter 13 and the secondary winding 15b. .. Further, FIG. 8 (b) shows an example in which a capacitor 51 is inserted between the AC / DC converter 12 and the primary winding 15a, and FIG. 8 (c) shows the AC / DC converter 13 and the secondary winding 15b. This is an example in which the capacitor 52 is inserted between the two. Further, as the high frequency transformer 15 applied to each of the above embodiments, one designed to intentionally generate a leakage inductance may be used.

（５）上記第４実施形態においては、１次側系統６４は単相交流系統であり、２次側系統７４は３相交流系統であったが、１次側を３相交流系統とし、２次側を単相交流系統にしてもよい。また、３相交流系統の側は、Δ結線にしてもよい。 (5) In the fourth embodiment, the primary side system 64 is a single-phase AC system and the secondary side system 74 is a three-phase AC system, but the primary side is a three-phase AC system and 2 The next side may be a single-phase AC system. Further, the side of the three-phase AC system may be connected by Δ.

さらに、１次側系統６４は、直流系統であってもよい。この場合、コンバータセル２０における交直変換器１１（図２参照）を削除し、コンデンサ１７の両端を１次側端子２５，２６に接続するとよい。換言すれば、本変形例は、１次側回路（２１）は、一対の１次側端子（２５，２６）と１次巻線（１５ａ）との間で電力を伝送する第２の交直変換器（１２）を有し、２次側回路（２２）は、２次側直流電圧（Ｖdc2）と２次巻線（１５ｂ）との間で電力を伝送する第３の交直変換器（１３）と、一対の２次側端子（２７，２８）と２次側直流電圧（Ｖdc2）との間で電力を伝送する第４の交直変換器（１４）と、を有するものになる。 Further, the primary side system 64 may be a DC system. In this case, the AC / DC converter 11 (see FIG. 2) in the converter cell 20 may be deleted, and both ends of the capacitor 17 may be connected to the primary terminals 25 and 26. In other words, in this modification, the primary side circuit (21) has a second AC / DC conversion in which power is transmitted between the pair of primary side terminals (25, 26) and the primary winding (15a). A third AC / DC converter (13) having a device (12) and the secondary side circuit (22) transmitting power between the secondary side DC voltage (Vdc2) and the secondary winding (15b). And a fourth AC / DC converter (14) that transmits power between the pair of secondary side terminals (27, 28) and the secondary side DC voltage (Vdc2).

（６）また、上記各実施形態において、コンバータセル２０の構成は、図２および図７に示したもの以外の、様々な構成を適用できる。すなわち、１次側ＡＣ端子間電圧Ｖ1に対応する変動成分が２次側ＡＣ端子間電圧Ｖ2に現れ、あるいは、２次側ＡＣ端子間電圧Ｖ2に対応する変動成分が１次側ＡＣ端子間電圧Ｖ1に現れるコンバータセルであれば、その構成にかかわらず、上記各実施形態と同様の効果を奏することができる。 (6) Further, in each of the above embodiments, various configurations other than those shown in FIGS. 2 and 7 can be applied to the configuration of the converter cell 20. That is, the variable component corresponding to the primary side AC terminal voltage V1 appears in the secondary side AC terminal voltage V2, or the variable component corresponding to the secondary side AC terminal voltage V2 is the primary side AC terminal voltage. As long as the converter cell appears in V1, the same effect as that of each of the above-described embodiments can be obtained regardless of its configuration.

（７）上記第１〜第３実施形態は、１次側系統の相数Ｍと、２次側系統の相数Ｎとが共に「３」である例について説明したが、相数Ｍ，Ｎは「４」以上であってもよく、相数Ｍは相数Ｎとは異なる値であってもよい。また、上記各実施形態において、コンバータセル２０の数は「１８」個であったが、コンバータセル２０の数は任意である。但し、各コンバータセル２０の仕様を同一にするためには、コンバータセル２０の数は、「Ｎ×Ｍ」の自然数倍にすることが好ましい。 (7) In the first to third embodiments, the example in which the number of phases M of the primary side system and the number of phases N of the secondary side system are both "3" has been described, but the numbers of phases M and N have been described. May be "4" or more, and the number of phases M may be a value different from the number of phases N. Further, in each of the above embodiments, the number of converter cells 20 is "18", but the number of converter cells 20 is arbitrary. However, in order to make the specifications of each converter cell 20 the same, it is preferable that the number of converter cells 20 is a natural number multiple of "N × M".

１１ 交直変換器（第１の交直変換器）
１２ 交直変換器（第２の交直変換器）
１３ 交直変換器（第３の交直変換器）
１４ 交直変換器（第４の交直変換器）
１５ 高周波トランス（トランス）
１５ａ １次巻線
１５ｂ ２次巻線
２０ コンバータセル（電力変換セル）
２０−１，２０−２ コンバータセル（第１の電力変換セル）
２０−３，２０−４ コンバータセル（第２の電力変換セル）
２０−５，２０−６ コンバータセル（第３の電力変換セル）
２０−７，２０−８ コンバータセル（第４の電力変換セル）
２０−９，２０−１０ コンバータセル（第５の電力変換セル）
２０−１１，２０−１２ コンバータセル（第６の電力変換セル）
２０−１３，２０−１４ コンバータセル（第７の電力変換セル）
２０−１５，２０−１６ コンバータセル（第８の電力変換セル）
２０−１７，１０−１８ コンバータセル（第９の電力変換セル）
２０−１０１ コンバータセル（第１の電力変換セル）
２０−１０２ コンバータセル（第２の電力変換セル）
２０−１０３ コンバータセル（第３の電力変換セル）
２１ １次側回路
２２ ２次側回路
２５，２６ １次側端子
２７，２８ ２次側端子
６０，６２，６４ １次側系統
７０，７２，７４ ２次側系統
１００，１２０，１３０，１４０ 電力変換装置
Ｖdc1 （１次側直流電圧）
Ｖdc2 （２次側直流電圧） 11 AC / DC converter (first AC / DC converter)
12 AC / DC converter (second AC / DC converter)
13 AC / DC converter (third AC / DC converter)
14 AC / DC converter (4th AC / DC converter)
15 High frequency transformer (transformer)
15a Primary winding 15b Secondary winding 20 Converter cell (power conversion cell)
20-1, 20-2 converter cell (first power conversion cell)
20-3, 20-4 converter cell (second power conversion cell)
20-5, 20-6 converter cell (third power conversion cell)
20-7, 20-8 converter cell (fourth power conversion cell)
20-9, 20-10 converter cell (fifth power conversion cell)
20-11, 20-12 converter cell (sixth power conversion cell)
20-13, 20-14 converter cell (7th power conversion cell)
20-15, 20-16 converter cell (8th power conversion cell)
20-17, 10-18 converter cell (9th power conversion cell)
20-101 converter cell (first power conversion cell)
20-102 converter cell (second power conversion cell)
20-103 Converter cell (third power conversion cell)
21 Primary side circuit 22 Secondary side circuit 25, 26 Primary side terminal 27, 28 Secondary side terminal 60, 62, 64 Primary side system 70, 72, 74 Secondary side system 100, 120, 130, 140 Power Converter Vdc1 (primary DC voltage)
Vdc2 (secondary DC voltage)

Claims (8)

１次側系統と、Ｎ相（Ｎは３以上の自然数）の交流系統である２次側系統との間に接続され、各々が一対の１次側端子と、一対の２次側端子とを有する第１〜第３の電力変換セルを備え、
前記第１〜第３の電力変換セルの前記１次側端子は直列接続されるとともに、前記１次側系統に接続され、
前記第１の電力変換セルの前記２次側端子は２次側第１相に係る箇所に接続され、
前記第２の電力変換セルの前記２次側端子は２次側第２相に係る箇所に接続され、
前記第３の電力変換セルの前記２次側端子は２次側第３相に係る箇所に接続されている
ことを特徴とする電力変換装置。 It is connected between the primary side system and the secondary side system which is an AC system of N phase (N is a natural number of 3 or more), and each has a pair of primary side terminals and a pair of secondary side terminals. Equipped with first to third power conversion cells having
The primary side terminals of the first to third power conversion cells are connected in series and connected to the primary side system.
The secondary side terminal of the first power conversion cell is connected to a portion related to the secondary side first phase.
The secondary side terminal of the second power conversion cell is connected to a portion related to the secondary side second phase.
A power conversion device characterized in that the secondary side terminal of the third power conversion cell is connected to a portion related to the secondary side third phase. 前記第１〜第３の電力変換セルは、それぞれ、
１次巻線と、前記１次巻線に対して絶縁された２次巻線とを有するトランスを備える
ことを特徴とする請求項１に記載の電力変換装置。 Each of the first to third power conversion cells
The power conversion device according to claim 1, further comprising a transformer having a primary winding and a secondary winding insulated from the primary winding. 前記１次側系統は、Ｍ相（Ｍは３以上の自然数）の交流系統であり、
各々が一対の前記１次側端子と、一対の前記２次側端子とを有する第４〜第９の電力変換セルをさらに備え、
前記第１〜第３の電力変換セルの前記１次側端子は直列接続されるとともに、１次側第１相に係る箇所に接続され、
前記第４〜第６の電力変換セルの前記１次側端子は直列接続されるとともに、１次側第２相に係る箇所に接続され、
前記第７〜第９の電力変換セルの前記１次側端子は直列接続されるとともに、１次側第３相に係る箇所に接続され、
前記第１の電力変換セル、前記第６の電力変換セル、および前記第８の電力変換セルの前記２次側端子は直列接続されるとともに、前記２次側第１相に係る箇所に接続され、
前記第２の電力変換セル、前記第４の電力変換セル、および前記第９の電力変換セルの前記２次側端子は直列接続されるとともに、前記２次側第２相に係る箇所に接続され、
前記第３の電力変換セル、前記第５の電力変換セル、および前記第７の電力変換セルの前記２次側端子は直列接続されるとともに、前記２次側第３相に係る箇所に接続されている
ことを特徴とする請求項１に記載の電力変換装置。 The primary paraphyly system is an M-phase (M is a natural number of 3 or more) AC system.
Further comprising fourth to ninth power conversion cells, each having a pair of the primary terminals and a pair of the secondary terminals.
The primary side terminals of the first to third power conversion cells are connected in series and connected to a portion related to the primary side first phase.
The primary side terminals of the 4th to 6th power conversion cells are connected in series and connected to a portion related to the primary side second phase.
The primary side terminals of the 7th to 9th power conversion cells are connected in series and connected to a portion related to the primary side third phase.
The first power conversion cell, the sixth power conversion cell, and the secondary terminal of the eighth power conversion cell are connected in series and connected to a portion related to the first phase of the secondary side. ,
The second power conversion cell, the fourth power conversion cell, and the secondary terminal of the ninth power conversion cell are connected in series and connected to a portion related to the second phase of the secondary side. ,
The third power conversion cell, the fifth power conversion cell, and the secondary terminal of the seventh power conversion cell are connected in series and connected to a portion related to the third phase of the secondary side. The power conversion device according to claim 1, wherein the power conversion device is characterized by the above. 前記トランスは前記１次巻線と前記２次巻線との間で１００Ｈｚ以上の周波数で電力を伝送するものであり、
前記第１〜第３の電力変換セルは、それぞれ、
前記１次側端子と前記１次巻線との間で電力を伝送する１次側回路と、
前記２次側端子と前記２次巻線との間で電力を伝送する２次側回路と、をさらに備える
ことを特徴とする請求項２に記載の電力変換装置。 The transformer transmits electric power between the primary winding and the secondary winding at a frequency of 100 Hz or higher.
Each of the first to third power conversion cells
A primary circuit that transmits power between the primary terminal and the primary winding,
The power conversion device according to claim 2, further comprising a secondary side circuit for transmitting electric power between the secondary side terminal and the secondary winding. 前記１次側回路は、一対の前記１次側端子と１次側直流電圧との間で電力を伝送する第１の交直変換器と、前記１次側直流電圧と前記１次巻線との間で電力を伝送する第２の交直変換器と、を有し、
前記２次側回路は、２次側直流電圧と前記２次巻線との間で電力を伝送する第３の交直変換器と、一対の前記２次側端子と前記２次側直流電圧との間で電力を伝送する第４の交直変換器と、を有する
ことを特徴とする請求項４に記載の電力変換装置。 The primary side circuit comprises a first AC / DC converter that transmits electric power between a pair of the primary side terminals and a primary side DC voltage, and the primary side DC voltage and the primary winding. Has a second AC / DC converter that transmits power between
The secondary side circuit comprises a third AC / DC converter that transmits electric power between the secondary side DC voltage and the secondary winding, and a pair of the secondary side terminals and the secondary side DC voltage. The power conversion device according to claim 4, further comprising a fourth AC / DC converter for transmitting power between them. 前記１次側回路は、一対の前記１次側端子と前記１次巻線との間で電力を伝送する第２の交直変換器を有し、
前記２次側回路は、２次側直流電圧と前記２次巻線との間で電力を伝送する第３の交直変換器と、一対の前記２次側端子と前記２次側直流電圧との間で電力を伝送する第４の交直変換器と、を有する
ことを特徴とする請求項４に記載の電力変換装置。 The primary circuit comprises a second AC / DC converter that transmits power between the pair of primary terminals and the primary winding.
The secondary side circuit comprises a third AC / DC converter that transmits electric power between the secondary side DC voltage and the secondary winding, and a pair of the secondary side terminals and the secondary side DC voltage. The power conversion device according to claim 4, further comprising a fourth AC / DC converter for transmitting power between them. 前記第１〜第３の電力変換セルのうち、前記１次側端子における対地電位の絶対値が最も高くなる電力変換セルと、前記２次側端子における対地電位の絶対値が最も高くなる電力変換セルとは、異なる電力変換セルである
ことを特徴とする請求項３に記載の電力変換装置。 Among the first to third power conversion cells, the power conversion cell having the highest absolute value of the ground potential at the primary side terminal and the power conversion having the highest absolute value of the ground potential at the secondary side terminal. The power conversion device according to claim 3, wherein the cell is a different power conversion cell. 各々が一対の１次側端子と、一対の２次側端子とを有する第１〜第９の電力変換セルを備える電力変換装置を、Ｍ相（Ｍは３以上の自然数）の１次側系統と、Ｎ相（Ｎは３以上の自然数）の２次側系統との間に接続する電力変換装置の接続方法であって、
前記第１〜第３の電力変換セルの前記１次側端子を直列接続するとともに、１次側第１相に係る箇所に接続し、
前記第４〜第６の電力変換セルの前記１次側端子を直列接続するとともに、１次側第２相に係る箇所に接続し、
前記第７〜第９の電力変換セルの前記１次側端子を直列接続するとともに、１次側第３相に係る箇所に接続し、
前記第１の電力変換セル、前記第６の電力変換セル、および前記第８の電力変換セルの前記２次側端子を直列接続するとともに、２次側第１相に係る箇所に接続し、
前記第２の電力変換セル、前記第４の電力変換セル、および前記第９の電力変換セルの前記２次側端子を直列接続するとともに、２次側第２相に係る箇所に接続し、
前記第３の電力変換セル、前記第５の電力変換セル、および前記第７の電力変換セルの前記２次側端子を直列接続するとともに、２次側第３相に係る箇所に接続し、かつ、
前記第１〜第３の電力変換セルのうち、前記１次側端子における対地電位の絶対値が最も高くなる電力変換セルと、前記２次側端子における対地電位の絶対値が最も高くなる電力変換セルと、が異なり、前記第４〜第６の電力変換セルのうち、前記１次側端子における対地電位の絶対値が最も高くなる電力変換セルと、前記２次側端子における対地電位の絶対値が最も高くなる電力変換セルと、が異なり、前記第７〜第９の電力変換セルのうち、前記１次側端子における対地電位の絶対値が最も高くなる電力変換セルと、前記２次側端子における対地電位の絶対値が最も高くなる電力変換セルと、が異なるように、各々の前記２次側端子を前記２次側系統に接続する
ことを特徴とする電力変換装置の接続方法。 A power conversion device including first to ninth power conversion cells, each having a pair of primary side terminals and a pair of secondary side terminals, is provided as an M-phase (M is a natural number of 3 or more) primary side system. And the connection method of the power conversion device connected between the N phase (N is a natural number of 3 or more) and the secondary side system.
The primary side terminals of the first to third power conversion cells are connected in series and connected to a portion related to the primary side first phase.
The primary side terminals of the 4th to 6th power conversion cells are connected in series and connected to a portion related to the primary side second phase.
The primary side terminals of the 7th to 9th power conversion cells are connected in series and connected to a portion related to the primary side third phase.
The first power conversion cell, the sixth power conversion cell, and the secondary terminal of the eighth power conversion cell are connected in series and connected to a portion related to the first phase of the secondary side.
The second power conversion cell, the fourth power conversion cell, and the secondary terminal of the ninth power conversion cell are connected in series and connected to a portion related to the second phase of the secondary side.
The third power conversion cell, the fifth power conversion cell, and the secondary terminal of the seventh power conversion cell are connected in series, and are connected to a portion related to the third phase of the secondary side. ,
Among the first to third power conversion cells, the power conversion cell having the highest absolute value of the ground potential at the primary side terminal and the power conversion having the highest absolute value of the ground potential at the secondary side terminal. The cell is different from the cell, and among the 4th to 6th power conversion cells, the power conversion cell having the highest absolute value of the ground potential at the primary side terminal and the absolute value of the ground potential at the secondary side terminal Is different from the power conversion cell having the highest value, and among the 7th to 9th power conversion cells, the power conversion cell having the highest absolute value of the ground potential at the primary side terminal and the secondary side terminal A method of connecting a power conversion device, which comprises connecting each of the secondary side terminals to the secondary side system so as to be different from the power conversion cell having the highest absolute value of the ground potential in the above.
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