Multiwinding transformer, and power conversion apparatus

Abstract

To provide a multiwinding transformer capable of enhancing voltage or increasing capacity of an insulation type power conversion apparatus, and a power conversion apparatus using the multiwinding transformer.SOLUTION: A multiwinding transformer for insulation has: a magnetic core having a plurality of leg portions (102); a primary winding (100) and a secondary winding (101) each wound around respective plurality of leg portions. Voltages with phases different from each other are input from a power converter (104) to primary windings wound around two different legs among the plurality of leg portions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-winding transformer having a plurality of windings, and an isolated power conversion device using a multi-winding transformer. [Background technology]

[0002] With the spread of renewable energy sources in power grids and the progress of the development of charging facilities for electric vehicles, medium- and high-voltage isolated AC / DC converters are becoming commonly used as power conversion devices that interconnect high-voltage AC power sources and low-voltage DC buses.

[0003] 2. Description of the Related Art As a conventional technique relating to an isolated AC / DC converter, the technique described in Patent Document 1 is known.

[0004] In the isolated AC / DC converter described in Patent Document 1 (FIG. 9), a multi-winding transformer with six independent windings is used as the insulating transformer. An AC output of a DC / AC converter is connected to each of three windings. An AC input of the AC / DC converter is connected to each of the other three windings.

[0005] The three DC / AC converters convert the DC power converted from the AC power from the external AC system into AC power with the same voltage phase. The AC power output by the three DC / AC converters is transmitted to the three AC / DC converters via a multi-winding transformer. The three AC / DC converters convert the AC power received via the multi-winding transformer into DC power. An electric vehicle is charged by the DC power output by each AC / DC converter. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 217721 Summary of the Invention [Problem to be solved by the invention]

[0007] In the above-mentioned conventional technology, insulation between the multiple windings in a multi-winding transformer is not taken into consideration. Furthermore, magnetic coupling through the magnetic core of the multi-winding transformer causes interference between the DC / AC converters, resulting in unbalanced operation of the multiple DC / AC converters. This makes it difficult to increase the voltage or capacity of an isolated AC / DC converter.

[0008] Therefore, the present invention provides a multi-winding transformer that can increase the voltage or capacity of an isolated power conversion device, and a power conversion device that uses this multi-winding transformer. [Means for solving the problem]

[0009] In order to solve the above problems, a multi-winding transformer according to the present invention is for insulating use and includes a magnetic core having a plurality of legs, and a primary winding and a secondary winding wound around each of the plurality of legs. Voltages having different phases are input from a power converter to the primary windings wound around two different legs of the plurality of legs.

[0010] In order to solve the above problems, a power conversion device according to the present invention includes a multi-winding transformer, the multi-winding transformer having a magnetic core with multiple legs, and multiple primary windings and multiple secondary windings wound around the multiple legs. The power conversion device according to the present invention further includes multiple first power converters that input AC voltage to the multiple primary windings, and multiple second power converters that input AC voltage from the multiple secondary windings. Two first power converters connected to primary windings wound around different two of the multiple legs output voltages with different phases from each other. Effect of the Invention

[0011] According to the present invention, it is possible to increase the voltage or capacity of an insulated power conversion device equipped with a multi-winding transformer.

[0012] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram showing an insulating type power conversion device according to a first embodiment of the present invention. [Diagram 2] 2 is a block diagram showing a configuration of a converter unit 104 in FIG. 1. [Diagram 3] 3 is a circuit diagram showing an example of an AC / DC converter unit 202 in FIG. 2. [Figure 4] 3 is a circuit diagram showing another example of the AC / DC converter unit 202 in FIG. 2. [Diagram 5] 3 is a circuit diagram showing an example of a DC / AC converter unit 205 in FIG. 2. [Figure 6] 3 is a circuit diagram showing another example of the DC / AC converter unit 205 in FIG. 2. [Figure 7] 2 is a block diagram showing a configuration of a converter unit 103 in FIG. 1. [Figure 8] 8 is a circuit diagram showing an example of an AC / DC converter unit in FIG. 7. [Figure 9] 8 is a circuit diagram showing another example of the AC / DC converter unit in FIG. 7. [Figure 10] 2 is a waveform diagram showing a portion of a PWM pulse voltage output from the converter unit 104 in FIG. 1 to the primary winding 100. [Figure 11] 1 is a waveform diagram showing the output voltage of converter unit 104, the input voltage of converter unit 103, and the magnetic flux in each leg 102 when the magnetic core of a multi-winding transformer has three legs 102. FIG. [Figure 12] FIG. 11 is a schematic configuration diagram showing an insulation type power conversion device according to a second embodiment. [Figure 13] FIG. 11 is a schematic configuration diagram showing an insulation type power conversion device according to a third embodiment. [Figure 14] FIG. 11 is a schematic configuration diagram showing an insulation type power conversion device according to a fourth embodiment. [Figure 15] FIG. 11 is a schematic configuration diagram showing an insulation type power conversion device according to a fifth embodiment. [Figure 16] FIG. 13 is a schematic configuration diagram showing an insulation type power conversion device according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiments of the present invention will be described with reference to the following Examples 1 to 6 with reference to the drawings.

[0015] In the various figures, the same reference numbers indicate the same components or components with similar functions. EXAMPLES

[0016] FIG. 1 is a schematic diagram showing the configuration of an insulation type power conversion device according to a first embodiment of the present invention.

[0017] The multi-winding transformer in the first embodiment has one magnetic core around which multiple windings are wound. The magnetic core has multiple legs 102 around which multiple windings are wound, and a frame portion 109 connecting the multiple legs 102. The multiple legs 102 are arranged in parallel with each other in the longitudinal direction and at equal intervals. The multiple legs 102 are magnetically coupled by the frame portion 109. In other words, the multiple legs 102 and the frame portion 109 form one magnetic circuit.

[0018] In each of the multiple (m (m≧2) in FIG. 1) legs 102, multiple (n (n≧2) in FIG. 1) primary windings 100 and multiple (n (n≧2) equal in number to the primary windings 100 in FIG. 1) secondary windings 101 are wound. In each leg 102, the n primary windings 100 are wound by split winding on one side in the longitudinal direction of the leg 102 so as to be adjacent to each other but not overlapping. In each leg 102, the n secondary windings 101 are wound by split winding on the other side in the longitudinal direction of the leg 102 so as to be adjacent to each other but not overlapping.

[0019] In each leg 102, a primary winding set 107 consisting of n primary windings 100 and a secondary winding set 108 consisting of n secondary windings 101 are located on one side and the other side, respectively, in the longitudinal direction of the leg 102. That is, in each leg 102, the primary winding set 107 and the secondary winding set 108 are wound by split winding.

[0020] A primary winding group 105 consisting of a plurality of (mn (m×n) pieces in FIG. 1) primary windings 100 in the m legs 102, and a secondary winding group 106 consisting of a plurality of (mn (m×n) pieces in FIG. 1) secondary windings 101 in the m legs 102 are located on one side and the other side in the longitudinal direction of the m legs 102, respectively. That is, in the m legs 102, the primary winding group 105 and the secondary winding group 106 are wound by split winding.

[0021] The winding configuration described above can improve electrical insulation between the multiple windings.

[0022] A converter unit 104 is connected to each of a plurality of (mn (m×n) in FIG. 1 ) primary windings 100. In the first embodiment, the converter unit 104 has a DC / AC converter section, i.e., an inverter section. An AC output of the inverter section is connected to each primary winding 100.

[0023] A converter unit 103 is connected to each of a plurality of (mn (m×n) in FIG. 1 ) secondary windings 101. In the first embodiment, the converter unit 103 has an AC / DC converter section. An AC input of the AC / DC converter section is connected to each secondary winding 101. In the first embodiment, the inverter section is operated as an AC / DC converter.

[0024] By using the multi-winding transformer, the multiple converter units 104, and the multiple converter units 103 as described above, the power conversion device of the first embodiment operates as a multiple-output isolated AC / DC converter having multiple DC outputs.

[0025] FIG. 2 is a block diagram showing a configuration of the converter unit 104 in FIG.

[0026] Converter unit 104 is composed of AC / DC converter section 202 and DC / AC converter section 205. The DC output of AC / DC converter section 202 and the DC input of DC / AC converter section 205 are connected by DC buses 203 and 204. Note that DC buses 203 and 204 are a negative DC bus and a positive DC bus, respectively. The AC input of AC / DC converter section 202 and the AC input of DC / AC converter section 205 are AC inputs 200 and 201 and AC outputs 206 and 207 of the converter unit, respectively.

[0027] FIG. 3 is a circuit diagram showing an example of the AC / DC converter unit 202 in FIG.

[0028] The AC / DC converter section 202 comprises a single-phase full-bridge circuit using a semiconductor device 300 in which a semiconductor switching element (IGBT in FIG. 3) and a diode are connected in anti-parallel, and a DC link capacitor 301 connected in parallel to the single-phase full-bridge circuit. The series connection points of the two semiconductor devices 300 in each half-bridge circuit are defined as AC inputs 200, 201. The parallel connection points of the two half-bridge circuits and the DC link capacitor 301 are connected to DC buses 203, 204 as DC outputs.

[0029] AC power input to AC inputs 200 and 201 is rectified by diodes and converted to DC power. The DC power charges DC link capacitor 301 and is output to DC buses 203 and 204.

[0030] FIG. 4 is a circuit diagram showing another example of the AC / DC converter unit 202 in FIG.

[0031] The AC / DC converter section 202 is composed of a parallel connection of a half-bridge circuit using a semiconductor device 300 in which a semiconductor switching element (IGBT in FIG. 4) and a diode are connected in anti-parallel, and a series-connected circuit of DC link capacitors 301, 302. The series-connected point of the two semiconductor devices 300 in the half-bridge circuit and the series-connected point of the two DC link capacitors 301, 302 are defined as AC inputs 200 and 201, respectively. Both ends of the half-bridge circuit, i.e., both ends of the series-connected circuit of the DC link capacitors 301, 302, are connected to DC buses 203, 203.

[0032] AC power input to AC inputs 200, 201 is rectified by diodes and converted to DC power, which alternately charges DC link capacitors 301, 302 depending on the polarity of the AC input voltage.

[0033] FIG. 5 is a circuit diagram showing an example of the DC / AC converter unit 205 in FIG.

[0034] The DC / AC converter unit 205 comprises a single-phase full-bridge circuit using semiconductor devices 300 in which semiconductor switching elements (IGBTs in FIG. 5) and diodes are connected in anti-parallel, and a DC link capacitor 301 connected in parallel to the single-phase full-bridge circuit. The series connection points of the two semiconductor devices 300 in each half-bridge circuit are AC outputs 206, 207. The parallel connection points of the two half-bridge circuits and the DC link capacitor 301 are connected to DC buses 203, 204 as DC inputs.

[0035] DC power input from DC buses 203 and 204 is converted into AC power by the switching operation of the semiconductor device 300. The AC power is output from AC outputs 206 and 207.

[0036] FIG. 6 is a circuit diagram showing another example of the DC / AC converter unit 205 in FIG.

[0037] The DC / AC converter unit 205 is composed of a parallel connection of a half-bridge circuit using a semiconductor device 300 in which a semiconductor switching element (IGBT in FIG. 6) and a diode are connected in anti-parallel, and a series-connected circuit of DC link capacitors 301, 302. The series-connected point of the two semiconductor devices 300 in the half-bridge circuit and the series-connected point of the two DC link capacitors 301, 302 are defined as AC outputs 206 and 207, respectively. Both ends of the half-bridge circuit, i.e., both ends of the series-connected circuit of the DC link capacitors 301, 302, are connected to DC buses 203, 204.

[0038] DC power input from DC buses 203 and 204 is converted into AC power by the switching operation of the semiconductor device 300. The AC power is output from AC outputs 206 and 207.

[0039] FIG. 7 is a block diagram showing a configuration of the converter unit 103 in FIG.

[0040] The converter unit 103 is composed of an AC / DC converter section. The DC output of the AC / DC converter section is connected to DC buses 502 and 503. The DC buses 502 and 503 are a positive DC bus and a negative DC bus, respectively. The AC inputs of the AC / DC converter section are AC inputs 500 and 501 of the converter unit 103.

[0041] FIG. 8 is a circuit diagram showing an example of the AC / DC converter unit in FIG.

[0042] The AC / DC converter section comprises a single-phase full-bridge circuit using semiconductor devices 300 in which semiconductor switching elements (IGBTs in FIG. 8) and diodes are connected in anti-parallel, and a DC link capacitor 301 connected in parallel to the single-phase full-bridge circuit. The series connection points of the two semiconductor devices 300 in each half-bridge circuit are AC inputs 500, 501. The parallel connection points of the two half-bridge circuits and the DC link capacitor 301 are connected to DC buses 502, 503 as DC outputs.

[0043] AC power input to AC inputs 500 and 501 is rectified by diodes and converted to DC power. The DC power charges the DC link capacitor 301 and is output to DC buses 502 and 503.

[0044] FIG. 9 is a circuit diagram showing another example of the AC / DC converter unit in FIG.

[0045] The AC / DC converter section is composed of a parallel connection of a half-bridge circuit using semiconductor device 300 in which a semiconductor switching element (IGBT in FIG. 9) and a diode are connected in anti-parallel, and a series-connected circuit of DC link capacitors 301, 302. The series-connected point of the two semiconductor devices 300 in the half-bridge circuit and the series-connected point of the two DC link capacitors 301, 302 are defined as AC inputs 500 and 501, respectively. Both ends of the half-bridge circuit, i.e., both ends of the series-connected circuit of DC link capacitors 301, 302, are connected to DC buses 502, 503.

[0046] AC power input to AC inputs 500 and 501 is rectified by diodes and converted to DC power. The DC power alternately charges DC link capacitors 301 and 302 depending on the polarity of the AC input voltage.

[0047] FIG. 10 is a waveform diagram showing a portion of a PWM pulse voltage outputted to the primary winding 100 by the converter unit 104 in FIG.

[0048] The m legs 102 of the magnetic core in the multi-winding transformer are numbered 1, 2, 3, ..., m, starting from the leftmost leg 102 in Fig. 1 and moving rightward. The output voltages of the n converter units 104 connected to the n primary windings 100 wound around the i-th (i = 1 to m) leg 102 are numbered V pi1 ,V pi2 ,…,V pin Let us assume that.

[0049] As shown in Figure 10, V p11 and V p1n The voltages are equal in magnitude and have zero phase difference, i.e., they are in phase. p11 and V p1n Not only V p1i (i=1 to m) have the same voltage magnitude and are in phase. Similarly, the output voltages V of the n converter units 104 connected to the n primary windings 100 wound around the i-th (i=1 to m) leg 102 are pij (j=1 to n) have the same voltage magnitude and are in phase.

[0050] As shown in Figure 10, V p11 and V pm1 The voltages are equal in magnitude and have a phase difference of Φ, where Φ = (360° / m) × (m-1). V p11 and V pm1 Not only V p11 and V pi1 (i=2 to m) have the same voltage magnitude and a phase difference of Φ(=(360° / m)×(m−1)). Similarly, the output voltages V of the n converter units 104 connected to the n primary windings 100 wound around the i-th (i=2 to m) leg 102 are pij (j=1~n) is V p1j For (j=1 to n), there is a phase difference Φ(=(360° / m)×(i−1)).

[0051] When the phase difference is set as described above, the output voltage V of the converter unit 104 connected to the primary windings wound on the adjacent legs 102 (i-th and i+1-th) is pij ,V pij+1 The phase difference is 360° / m. Therefore, in the first embodiment, the output voltages of the n converter units 104 connected to the n primary windings 100 wound around each leg 102 are in phase. In the first embodiment, the output voltages of the converter units 104 connected to the primary windings wound around any two adjacent legs 102 out of the m legs 102 have the same phase difference (=360° / m). In the first embodiment, V pij (i=1~m, j=1~n) are equal in size.

[0052] For example, if there are three legs 102, V p1j and V p2j The phase difference between V and V is 120° (=360° / 3), p2j and V p3j The phase difference is 120° (=360° / 3).

[0053] The output voltages of the converter units 104 connected to the primary windings wound on any two adjacent legs 102 out of the m number of legs 102 have the same phase difference (=360° / m). This reduces the interference received or imparted by the converter units 104 connected to the primary windings wound on each leg 102 due to mutual interference (e.g., cross current) between the converter units 104 connected to the primary windings wound on different legs 102 of the multi-winding transformer. This improves the balance of operation of the multiple (m×n) converter units 104 connected to the multiple (m×n) primary windings in the multiple multi-winding transformer.

[0054] 11 is a waveform diagram showing the output voltage of converter unit 104 connected to each primary winding 100, the input voltage of converter unit 103 connected to each secondary winding 101, and the magnetic flux in each leg 102, when the magnetic core of a multi-winding transformer has three legs 102. The horizontal axis indicates the phase.

[0055] The output voltages 1300, 1304, and 1307 of the converter unit 104 are V p11 ~V p1n ,V p21 ~V p2n ,V p31 ~V p3n Corresponds to.

[0056] The input voltages 1301, 1305, and 1308 of the converter unit 103 are V s11 ~V s1n ,V s21 ~V s2n ,V s31 ~V s3n Corresponds to.

[0057] In FIG. 1, similarly to the output voltage of the converter unit 104, the output voltages of the n converter units 103 connected to the n secondary windings 101 wound around the i-th (i=1 to m) leg 102 are sequentially expressed as V si1 ,V si2 ,…,V sin Let us assume that.

[0058] Magnetic fluxes 1302, 1306, and 1309 correspond to the magnetic fluxes in the first, second, and third legs 102, respectively.

[0059] 11, the phase difference between the output voltages 1300 and 1304 is 120°. The phase difference between the output voltages 1300 and 1307 is 240°, and therefore the phase difference between the output voltages 1304 and 1307 is 120°. Note that the phase difference between the output voltages 1307 and 1300 of the converter unit 104 is also 120°. This balances the operations of the multiple converter units 104, so that the magnitudes (amplitudes) of the magnetic fluxes 1302, 1306, and 1309 become uniform.

[0060] 11, input voltage 1301 lags in phase by δ with respect to output voltage 1300. Similarly, input voltage 1305 lags in phase by δ with respect to output voltage 1304, and input voltage 1308 lags in phase by δ with respect to output voltage 1307. Here, in the corresponding converter unit 103, the switching of the semiconductor switching element is controlled by a control device (not shown) so that the phase lag of the input voltage with respect to the output voltage becomes δ.

[0061] Power is transferred from converter unit 104 to converter unit 103 via a multi-winding transformer according to a phase lag δ.

[0062] As described above, according to the first embodiment, the multi-winding transformer includes a plurality of legs 102 around which the primary winding 100 and the secondary winding 101 are wound by split winding, and voltages of different phases are input from the converter units 104 to the primary windings wound on different legs. This improves the balance of the magnitude of the magnetic flux in the plurality of legs and improves the balance of the operation of the plurality of converter units 104.

[0063] Therefore, the power loss of the isolated power conversion device can be reduced, and the capacity of the isolated power conversion device can be increased.

[0064] It should be noted that each leg 102 needs to have at least one primary winding and one secondary winding.

[0065] According to the first embodiment, each winding (100, 101, 800, 801) is wound by split winding in each leg 102. This improves electrical insulation between the windings. Therefore, an insulated power converter equipped with a multi-winding transformer can be made to have a high voltage or a large capacity.

[0066] Furthermore, according to the first embodiment, the power capacity and the number of outputs of the insulated multi-output power converter can be easily set by changing the number of legs 102 having the same configuration including the windings.

[0067] In this way, according to the first embodiment, the insulation type power conversion device can be made to have a higher voltage or a larger capacity. EXAMPLES

[0068] FIG. 12 is a schematic configuration diagram showing an insulation type power conversion device according to a second embodiment of the present invention.

[0069] The following describes the differences from the first embodiment.

[0070] As shown in Fig. 12, the AC inputs of a plurality (n (n≧2) in Fig. 12) of converter units 104, whose AC outputs are connected to a plurality (n (n≧2) in Fig. 12) of primary windings 100 wound around each leg 102, are connected in series with each other. A single-phase AC power supply 1100 is connected to both ends of the series connection of the AC inputs, i.e., to connection terminals 1101 and 1102. This makes it possible to increase the power supply voltage of the single-phase AC power supply 1100.

[0071] As shown in FIG. 12, the DC output of multiple (n (n≧2) in FIG. 12) converter units 103, whose AC inputs are connected to multiple (n (n≧2) in FIG. 12) secondary windings 101 wound around each leg 102, is connected to either an electric vehicle 1103 or a battery 1104.

[0072] In this manner, according to the isolated power conversion apparatus of the second embodiment, a plurality of batteries 1104 or a plurality of electric vehicles 1103, or a battery 1104 and an electric vehicle 1103 can be charged simultaneously. EXAMPLES

[0073] FIG. 13 is a schematic diagram showing the configuration of an insulation type power conversion device according to a third embodiment of the present invention.

[0074] The following describes the differences from the first embodiment.

[0075] In each of the multiple (three in FIG. 13) legs 102, the multiple (six in FIG. 13) primary windings are divided into multiple (three in FIG. 13) primary winding sets 2040 consisting of multiple (two in FIG. 13) primary windings.

[0076] Here, the three primary winding sets 2040 are referred to as a first primary winding set, a second primary winding set, and a third primary winding set, from the top in FIG.

[0077] The AC inputs of two converter units 204 (corresponding to converter units 104) connected to the first primary winding set are connected in series by a connecting conductor section 1202. The series connection of the AC inputs of such converter units 204 in the three legs 102 is connected in series by connecting conductor sections 1203, 1204. That is, the AC inputs of six converter units 204 connected to the three first primary winding sets wound around the three legs 102 are connected in series. A single-phase AC power source 1100 is connected to both ends of the series connection of the AC inputs of the six converter units 204, i.e., to the connection terminals 1201, 1205.

[0078] Similarly, for the second primary winding set and the third primary winding set, both ends of the series connection of the AC inputs of the six converter units are connected.

[0079] According to the third embodiment, the power supply voltage of the single-phase AC power supply 1100 can be increased. EXAMPLES

[0080] FIG. 14 is a schematic configuration diagram showing an insulation type power conversion device according to a fourth embodiment of the present invention.

[0081] The following describes the differences from the first embodiment.

[0082] As shown in FIG. 14, connection terminals 701 and 702 of a plurality of secondary windings 101 wound around each leg 102 are connected to an AC input of one converter unit 103 .

[0083] According to the fourth embodiment, the number of converter units 103 can be reduced while maintaining the total power capacity of the isolated power conversion device. EXAMPLES

[0084] Fifth embodiment FIG. 15 is a schematic configuration diagram showing an insulation type power conversion device according to a fifth embodiment of the present invention.

[0085] The following describes the differences from the first embodiment.

[0086] The isolated power conversion device of the fifth embodiment includes a first isolated AC / DC converter in which a magnetic core of a multi-winding transformer has a frame portion 109, and a second isolated AC / DC converter in which a magnetic core of a multi-winding transformer has a frame portion 804. Both the first isolated AC / DC converter and the second isolated AC / DC converter have the same configuration as the isolated AC / DC converter of the first embodiment (FIG. 1).

[0087] A tertiary winding 800 is wound around each leg of the magnetic core of the multi-winding transformer of the first isolated AC / DC converter. A tertiary winding 801 is wound by split winding around each leg of the magnetic core of the multi-winding transformer of the second isolated AC / DC converter.

[0088] A tertiary winding 800 wound around the i-th leg of a magnetic core of a multi-winding transformer of a first isolated AC / DC converter and a tertiary winding 801 wound around the i-th leg of a magnetic core of a multi-winding transformer of a second isolated AC / DC converter are connected by connecting conductor portions 802, 803 to form a loop circuit.

[0089] When an imbalance occurs between the magnetic flux in the i-th leg of the magnetic core of the multi-winding transformer of the first isolated AC / DC converter and the magnetic flux in the i-th leg of the magnetic core of the multi-winding transformer of the second isolated AC / DC converter, the imbalance is suppressed by the magnetic flux generated by the induced current flowing in the loop circuit consisting of the tertiary windings 800 and 801. This balances the operations of the multiple converter units 104. EXAMPLES

[0090] FIG. 16 is a schematic diagram showing the configuration of an insulation type power conversion device according to a sixth embodiment of the present invention.

[0091] The following describes the differences from the first embodiment.

[0092] The multi-winding transformer in the sixth embodiment has a plurality of magnetic cores (three in FIG. 16) each having two legs. The two legs are connected by a connecting part. This makes the magnetic core have a square frame shape. As in the first embodiment, a primary winding and a secondary winding are wound around each leg by split winding. As in the first embodiment, converter units 104 and 103 are connected to the primary winding and the secondary winding, respectively.

[0093] The three magnetic cores 900, 901, and 902 are magnetically coupled such that their connecting portions form the same angle with each other, thereby forming a multi-winding transformer having six legs.

[0094] According to the sixth embodiment, the installation area of ​​the multi-winding transformer can be reduced by configuring the multi-winding transformer three-dimensionally.

[0095] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. In addition, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0096] For example, the semiconductor switching elements used in the converter units 103 and 104 are not limited to IGBTs, but may be MOSFETs, junction bipolar transistors, or the like. [Explanation of symbols]

[0097] 100...primary winding, 101...secondary winding, 102...leg portion, 103...converter unit, 104...converter unit, 105...primary winding group, 106...secondary winding group, 107...primary winding set, 108...secondary winding set, 109...frame portion, 200, 201...AC input, 202...AC / DC converter portion, 203, 204...DC bus, 205...DC / AC converter portion, 206, 207...AC output, 300...semiconductor device, 301, 302...DC link capacitor, 500, 501...AC input, 502, 503...DC bus, 701, 702...connection connection terminal, 800, 801... tertiary winding, 802, 803... connecting conductor portion, 804... frame portion, 900, 901, 902... magnetic core, 1100... single-phase AC power source, 1101... connection terminal, 1103... electric vehicle, 1104... battery, 1201... connection terminal, 1202, 1203, 1204... connecting conductor portion, 1205... connection terminal, 1300... output voltage, 1301... input voltage, 1302... magnetic flux, 1304... output voltage, 1305... input voltage, 1306... magnetic flux, 1307... output voltage, 1308... input voltage, 1309... magnetic flux, 2040... primary winding set,

Claims

1. In multi-winding transformers for insulation, a magnetic core having a plurality of legs; a primary winding and a secondary winding wound around each of the plurality of legs; A multi-winding transformer, characterized in that voltages of different phases are input from a power converter to the primary windings wound around two different legs among the plurality of legs.

2. 2. The multi-winding transformer according to claim 1, In the magnetic core, the legs are juxtaposed and magnetically coupled to each other, a phase difference between the voltage input to the primary winding wound on any one of the plurality of legs and the voltage input to the primary winding wound on the leg adjacent to the any one of the plurality of legs is 360° / m, where m is the number of the plurality of legs.

3. 2. The multi-winding transformer according to claim 1, A multi-winding transformer, wherein the primary winding and the secondary winding are wound by split winding.

4. 4. The multi-winding transformer according to claim 3, The primary winding and the secondary winding are each provided in a plurality of pieces, 1. A multi-winding transformer, comprising: a first winding connected to a first terminal of the first transformer; a second winding connected to a second terminal of the second transformer;

5. 5. The multi-winding transformer according to claim 4, A multi-winding transformer, wherein the plurality of secondary windings are connected in parallel.

6. In a power conversion device having an insulating multi-winding transformer, The multi-winding transformer includes a magnetic core having a plurality of legs, and a plurality of primary windings and a plurality of secondary windings wound around the plurality of legs, a plurality of first power converters that input AC voltages to the plurality of primary windings; a plurality of second power converters receiving AC voltages from the plurality of secondary windings; Equipped with A power conversion device characterized in that the two first power converters connected to the primary windings wound around two different legs among the plurality of legs output voltages with different phases from each other.

7. 7. The power conversion device according to claim 6, In the magnetic core, the legs are juxtaposed and magnetically coupled to each other, a phase difference between the AC voltage input by the first power converter to the primary winding wound around any one of the plurality of legs and the AC voltage input by the first power converter to the primary winding wound around the leg adjacent to the any one of the plurality of legs is 360° / m, where m is the number of the plurality of legs.

8. 7. The power conversion device according to claim 6, A power conversion device, characterized in that the plurality of primary windings and the plurality of secondary windings are wound by split winding.

9. 7. The power conversion device according to claim 6, the plurality of AC inputs of the plurality of first power converters are connected in series with each other; A power conversion device, characterized in that the plurality of AC inputs connected in series are connected to an AC power source.

10. 7. The power conversion device according to claim 6, a plurality of the primary windings and a plurality of the secondary windings are wound around each of the plurality of legs; A power conversion device, characterized in that the plurality of primary windings are wound by split winding, and the plurality of secondary windings are wound by split winding.

11. The power converter according to claim 10, The power conversion device, wherein the plurality of secondary windings are connected in parallel.

12. A power conversion device including a first multi-winding transformer and a second multi-winding transformer for insulation, Each of the first multi-winding transformer and the second multi-winding transformer comprises: a magnetic core having a plurality of legs, and a plurality of primary windings and a plurality of secondary windings wound around the plurality of legs; a plurality of first power converters that input AC voltages to the plurality of primary windings; a plurality of second power converters receiving AC voltages from the plurality of secondary windings; Equipped with the two first power converters connected to the primary windings wound around two different legs among the plurality of legs output voltages having different phases from each other; A power conversion device characterized in that a tertiary winding wound around each of the multiple legs of the magnetic core of the first multi-winding transformer and a tertiary winding wound around each of the multiple legs of the magnetic core of the second multi-winding transformer form a loop circuit.

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