Power conversion device

Abstract

The present disclosure provides a power conversion device that reduces the influence of magnetic flux in bus bars of each phase. The power conversion device has a first inverter connected to one end of a three-phase winding of an open-circuit winding motor and a second inverter connected to the other end of the three-phase winding. The power conversion device has a first conductor of three phases connecting one end of each phase of the three-phase winding to each phase of the first inverter and a second conductor of three phases connecting the other end of each phase of the three-phase winding to each phase of the second inverter, each phase of the first conductor and each phase of the second conductor being arranged in a manner in which the conductors of the same phase are parallel and current flows in opposite directions.

Description

Technical Field

[0001] This disclosure relates to a power conversion device, and more specifically, to a power conversion device having a first inverter connected to one end of a three-phase winding of an open-circuit winding motor and a second inverter connected to the other end of the three-phase winding. Background Technology

[0002] Conventionally, power conversion devices have been proposed in which the U-phase busbars, V-phase busbars, and W-phase busbars of the first inverter, and the U-phase busbars, V-phase busbars, and W-phase busbars of the second inverter are arranged in a straight line in this order (for example, see Patent Document 1). Each of the U-phase, V-phase, and W-phase busbars of the first inverter is connected to a three-phase coil of a first rotating motor, and each of the U-phase, V-phase, and W-phase busbars of the second inverter is connected to a three-phase coil of a second rotating motor. Sensors for detecting the current flowing through each of the U-phase, V-phase, and W-phase busbars of the first and second inverters are installed. Furthermore, a converter busbar is arranged between the W-phase busbar of the first inverter and the U-phase busbar of the second inverter.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-164244 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] However, in the aforementioned power conversion device, in order to reduce interference caused by magnetic flux in the busbars of each phase, the distance between the busbars of each phase needs to be increased, resulting in a larger device size. Furthermore, when using sensors that detect the magnetic flux generated by the current flowing through the busbars as sensors for detecting the current flowing through each busbar, the sensor values ​​also need to be calibrated due to the influence of magnetic flux from different phases.

[0008] The main objective of the power conversion device disclosed herein is to reduce the influence of magnetic flux in the busbars of each phase.

[0009] Solution for solving the problem

[0010] The power conversion device disclosed herein employs the following means to achieve the aforementioned main objectives.

[0011] The power conversion device disclosed herein includes a first inverter connected to one end of the three-phase winding of an open-circuit winding motor and a second inverter connected to the other end of the three-phase winding. The power conversion device is characterized by having:

[0012] The first conductor of the three phases connects one end of each phase of the three-phase winding to each phase of the first inverter; and

[0013] The second conductor of the three phases connects the other end of each phase of the three-phase winding to each phase of the second inverter.

[0014] The phases of the first conductor and the phases of the second conductor are arranged such that conductors of the same phase are parallel and the current flows in opposite directions.

[0015] In the power conversion device of this disclosure, each phase of the first conductor and each phase of the second conductor are arranged such that conductors of the same phase are parallel and current flows in opposite directions. Specifically, the first conductor of the U phase of the first inverter and the second conductor of the U phase of the second inverter are close together and parallel with current flowing in opposite directions; the first conductor of the V phase of the first inverter and the second conductor of the V phase of the second inverter are close together and parallel with current flowing in opposite directions; and the first conductor of the W phase of the first inverter and the second conductor of the W phase of the second inverter are close together and parallel with current flowing in opposite directions. Because conductors of the same phase are close together and parallel with current flowing in opposite directions, the magnetic flux generated by the first conductor of each phase is canceled out by the magnetic flux generated by the second conductor of the same phase (the magnetic flux generated by the first conductor of the U phase of the first inverter is canceled out by the magnetic flux generated by the second conductor of the U phase of the second inverter (the same applies to the V and W phases)). This reduces the influence of magnetic flux in the busbars of each phase.

[0016] In the power conversion device disclosed herein, the cross-sections of the first conductor and the second conductor may also be rectangular, and the phases of the first conductor and the second conductor may be arranged such that conductors of the same phase face each other or are on the same plane. That is, they may be arranged such that the long side face of the cross-section of the first conductor and the long side face each other, or they may be arranged such that the long side face of the cross-section of the first conductor and the long side face of the cross-section of the second conductor are on the same plane.

[0017] In the power conversion device disclosed herein, the phases of the first conductor and the phases of the second conductor may be arranged such that the distance between conductors of the same phase is shorter than the distance between conductors of different phases. This further reduces the influence of magnetic flux from different phases.

[0018] In the power conversion device disclosed herein, an insulating wall may also be provided between the first conductor and the second conductor, which are in phase. This allows for more reliable prevention of unintended short circuits.

[0019] In the power conversion device disclosed herein, each phase of the first conductor and each phase of the second conductor may be covered with insulating material. This allows for more reliable prevention of unexpected short circuits.

[0020] In the power conversion device disclosed herein, at least one of the positive or negative side of the same phase of the connection terminals of each phase of the first inverter and the connection terminals of each phase of the second inverter may be configured as a common terminal. In this way, the number of terminals can be reduced.

[0021] In the power conversion device disclosed herein, at least one of the positive or negative side lines connecting the first inverter and the second inverter may have a switch for connecting and disconnecting. This allows for switching between star and delta connections of the three-phase windings of an open-circuit winding motor.

[0022] In the power conversion device disclosed herein, a three-phase current sensor may be provided, which is positioned at the same distance from the conductors of the same phase between each phase of the first conductor and each phase of the second conductor. That is, a current sensor for the U phase is positioned at the same distance from the first conductor of the U phase of the first inverter as from the second conductor of the U phase of the second inverter; a current sensor for the V phase is positioned at the same distance from the first conductor of the V phase of the first inverter as from the second conductor of the V phase of the second inverter; and a current sensor for the W phase is positioned at the same distance from the first conductor of the W phase of the first inverter as from the second conductor of the W phase of the second inverter. Positioning the current sensors at the same distance from conductors of the same phase with opposite current directions enhances the magnetic flux of the conductors of the same phase, thus improving the detection accuracy of the current sensors.

[0023] In the power conversion device of this disclosure that incorporates such a three-phase current sensor, the three-phase current sensor may be disposed between conductors of the same phase. This further enhances the magnetic flux of each conductor of the same phase, thereby further improving the detection accuracy of the current sensor. In this case, each phase of the first conductor and each phase of the second conductor may have recesses formed on opposite surfaces of the conductors of the same phase, and the three-phase current sensor may be disposed such that it fits into the recesses of the conductors of the same phase. Alternatively, a magnetic core with an open end may be disposed around each phase of the first conductor and each phase of the second conductor. This further improves the detection accuracy of the current sensor. Attached Figure Description

[0024] Figure 1This is a schematic structural diagram showing the electrical structure of the drive device 20, which includes the power conversion device 30 as disclosed in one embodiment.

[0025] Figure 2 This is a schematic structural diagram illustrating the structure of the drive device 20 of the power conversion device 30 including the embodiment.

[0026] Figure 3 This is an explanatory diagram schematically showing a cross-section near the connection portion of the power conversion device 30 in the embodiment that is connected to the open-circuit winding motor 70.

[0027] Figure 4 This is an explanatory diagram schematically showing a cross-section near the connection between the positive-side power line 24p and the negative-side power line 24n of the power conversion device 30 in the embodiment.

[0028] Figure 5 This is an illustration diagram schematically showing the magnetic flux generated by the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50.

[0029] Figure 6 This is an illustrative diagram showing the first inverter 40 and the second inverter 50, which are composed of three four-in-one modules.

[0030] Figure 7 This is an explanatory diagram schematically showing the cross-section near the connection of the positive side power line 24p and the negative side power line 24n of the power conversion device 30 when the first inverter 40 and the second inverter 50 are composed of three four-in-one modules.

[0031] Figure 8 This is an illustrative diagram showing the first inverter 40 and the second inverter 50 when they are composed of a single twelve-in-one module.

[0032] Figure 9 This is an explanatory diagram schematically showing the cross-section near the connection of the positive side power line 24p and the negative side power line 24n of the power conversion device 30 when the first inverter 40 and the second inverter 50 are composed of a 12-in-1 module.

[0033] Figure 10 This is an explanatory diagram schematically showing the cross-section near the connection of the positive side power line 24p and the negative side power line 24n of the power conversion device 30 when the first inverter 40 and the second inverter 50 are composed of two twelve-in-one modules.

[0034] Figure 11This is an explanatory diagram of a modified power conversion device 30, schematically showing the busbars 46U, 46V, and 46W of the first inverter 40 and the busbars 56U, 56V, and 56W of the second inverter 50 covered by insulating coverings 47U, 47V, and 47W.

[0035] Figure 12 This is an explanatory diagram of a modified power conversion device 30, schematically showing a partition wall 66U, 66V, 66W installed between the in-phase busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50.

[0036] Figure 13 This is an explanatory diagram of a power conversion device 30 that schematically illustrates a modified example of a power conversion device 30 in which the negative side connection terminals of the same phase use common negative side connection terminals 4454U, 4454V, and 4454V.

[0037] Figure 14 This is an explanatory diagram illustrating a cross-section near the connection portion of the positive-side power line 24p and the negative-side power line 24n in a power conversion device 30, which schematically shows a modified example of a device using shared negative-side common connection terminals 4454U, 4454V, and 4454V for the negative-side connection terminals of the same phase.

[0038] Figure 15 This is an explanatory diagram of a power conversion device 30 that schematically illustrates a modified example of a positive-side common connection terminal 4252U, 4252V, 4252V used for the positive-side connection terminals of the same phase.

[0039] Figure 16 This is an explanatory diagram showing a cross-section near the connection of the positive-side power line 24p and the negative-side power line 24n in a power conversion device 30, which is a modified example of a device using common positive-side connection terminals 4252U, 4252V, and 4252V for positive-side connection terminals of the same phase.

[0040] Figure 17 This is an explanatory diagram of a modified power conversion device 30, which schematically illustrates a modified example in which the positive side connection terminals of the same phase are set as common positive side common connection terminals 4252U, 4252V, and 4252V, and the negative side connection terminals of the same phase are set as common negative side common connection terminals 4454U, 4454V, and 4454V.

[0041] Figure 18This is an explanatory diagram schematically showing a cross-section near the connection portion of the positive-side power line 24p and the negative-side power line 24n in a modified example of a power conversion device 30, in which the positive-side connection terminals of the same phase are set as common positive-side common connection terminals 4252U, 4252V, and 4252V, and the negative-side connection terminals of the same phase are set as common negative-side common connection terminals 4454U, 4454V, and 4454V.

[0042] Figure 19 This is an explanatory diagram of a modified power conversion device 30, schematically showing a configuration in which the long-side cross-sections of the same-phase busbars face each other and the long-side cross-sections of the opposite-phase busbars face each other.

[0043] Figure 20 This is an explanatory diagram of a power conversion device 30 schematically showing a modified example in which the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50 are arranged such that the planes along the long side of the cross section are in the same plane.

[0044] Figure 21 This is an explanatory diagram of a modified power conversion device 30, schematically showing the current sensors 64U, 64V, and 64W arranged between in-phase busbars at positions offset from the center at the same distance from the in-phase busbars.

[0045] Figure 22 This is an explanatory diagram of a modified power conversion device 30, schematically showing the current sensors 64U, 64V, and 64W arranged between in-phase busbars at positions offset from the center at the same distance from the in-phase busbars.

[0046] Figure 23 This is an explanatory diagram of a modified power conversion device 30, schematically showing the current sensors 64U, 64V, and 64W arranged between in-phase busbars at positions offset from the center at the same distance from the in-phase busbars.

[0047] Figure 24 This is an explanatory diagram of a modified power conversion device 30, schematically showing that the face-to-face surfaces of the in-phase busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50 are respectively formed with recesses and current sensors 64U, 64V, 64W are arranged in the center of the recesses.

[0048] Figure 25This is an explanatory diagram of a modified power conversion device 30, schematically showing the surrounding area of ​​the in-phase busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50, with magnetic cores 68U, 68V, 68W. Detailed Implementation

[0049] Next, the methods (implementation methods) for carrying out this disclosure will be described. Figure 1 This is a schematic structural diagram showing the electrical structure of the drive device 20, which includes the power conversion device 30 as an embodiment of this disclosure. Figure 2 This is a schematic structural diagram illustrating the structure of the drive device 20 of the power conversion device 30 including the embodiment. Figure 3 This is an explanatory diagram schematically showing a cross-section near the connection portion of the power conversion device 30 in the embodiment that is connected to the open-circuit winding motor 70. Figure 4 This is an explanatory diagram schematically showing a cross-section near the connection between the positive-side power line 24p and the negative-side power line 24n of the power conversion device 30 in the embodiment. The drive device 20 of the embodiment includes a battery 22, a power conversion device 30, and an open-circuit winding motor 70.

[0050] Battery 22 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, with its positive and negative terminals connected to positive-side electric field line 24p and negative-side electric field line 24n. A smoothing capacitor 26 is installed between the positive-side electric field line 24p and the negative-side electric field line 24n.

[0051] The power conversion device 30 includes a first inverter 40, a second inverter 50, and connection switches 60p and 60n.

[0052] The first inverter 40 is connected to the positive-side power line 24p and the negative-side power line 24n connected to the battery 22, and has six transistors T11 to T16 as switching elements and six diodes D11 to D16 connected in parallel with the six transistors T11 to T16. Transistors T11 to T16 are, for example, constructed of SiC-MOSFETs (SiC - Metal Oxide Semiconductor Field-Effect Transistors). Pairs of transistors T11 to T16 (transistor T11 and transistor T14, transistor T12 and transistor T15, transistor T13 and transistor T16) are configured such that they are the source side and drain side relative to the positive-side power line 24p and the negative-side power line 24n, respectively. Figure 1 and Figure 4As shown, it is connected to the positive side power line 24p via positive side connection terminals 42U, 42V, and 42W, and connected to the negative side power line 24n via negative side connection terminals 44U, 44V, and 44W. Additionally, as... Figure 1 and Figure 2 As shown, the connection points of pairs of transistors T11 to T16 are connected to one end of the three-phase coils 72U, 72V, and 72W of the open-circuit winding motor 70 via busbars 46U, 46V, and 46W formed of conductive metal. It should be noted that in the first inverter 40, each phase consists of two pairs of transistors and two diodes connected in parallel, forming a module (two-in-one module) for each phase. The first inverter 40 is composed of three modules.

[0053] The second inverter 50 is connected to the positive-side power line 24p and the negative-side power line 24n of the battery 22, sandwiching the first inverter 40 via the battery 22. It has six transistors T21-T26 as switching elements and six diodes D21-D26 connected in parallel with each of the six transistors T21-T26. Transistors T11-T16, like those in the first inverter 40, are constructed of SiC-MOSFETs. Pairs of transistors T21-T26 (transistor T21 and transistor T24, transistor T22 and transistor T25, transistor T23 and transistor T26) are arranged such that they are the source and drain sides relative to the positive-side power line 24p and the negative-side power line 24n, respectively. Figure 1 and Figure 4 As shown, it is connected to the positive side power line 24p via positive side connection terminals 52U, 52V, and 52W, and connected to the negative side power line 24n via negative side connection terminals 54U, 54V, and 54W. Additionally, as... Figure 1 and Figure 2 As shown, the connection points of pairs of transistors T21 to T26 are connected to the other ends of the three-phase coils 72U, 72V, and 72W of the open-circuit winding motor 70 via busbars 56U, 56V, and 56W formed of conductive metal. It should be noted that, similar to the first inverter 40, each phase consists of two pairs of transistors and two diodes connected in parallel, forming a module (two-in-one module) for each phase. The second inverter 50 also consists of three modules.

[0054] A connection switch 60p is installed between the first inverter 40 and the second inverter 50 on the positive side power line 24p, and a connection switch 60n is installed between the first inverter 40 and the second inverter 50 on the negative side power line 24n. Similarly, the connection switches 60p and 60n, as well as the transistors T11 to T16 of the first inverter 40 and T21 to T26 of the second inverter 50, are composed of SiC-MOSFETs.

[0055] The open-circuit winding motor 70 is a generator motor formed by using the two ends of the three-phase coils 72U, 72V, and 72W of the u-phase, v-phase, and w-phase as connection terminals. The three connection points of the two pairs of transistors of the first inverter 40 are connected to one end of the three-phase coils 72U, 72V, and 72W through busbars 46U, 46V, and 46W. The three connection points of the two pairs of transistors of the second inverter 50 are connected to the other end of the three-phase coils 72U, 72V, and 72W through busbars 56U, 56V, and 56W.

[0056] In the power conversion device 30 of the embodiment, with the connection switches 60p and 60n disconnected, the transistors T21 to T23 of the upper arm of the second inverter 50 turned on, and the transistors T24 to T26 of the lower arm disconnected, the open-circuit winding motor 70 can be star-connected and driven by switching the transistors T11 to T16 of the first inverter 40. That is, by disconnecting the connection switches 60p and 60n and turning on the transistors T21 to T23 of the upper arm of the second inverter 50, the u-phase, v-phase, and w-phase of the open-circuit winding motor 70 are connected. The transistors T21 to T23 form a neutral point, and the open-circuit winding motor 70 is driven by the first inverter 40 as a star-connected motor. On the other hand, by switching transistors T11 to T16 of the first inverter 40 and transistors T21 to T26 of the second inverter 50 with the connection switches 60p and 60n turned on, the open-circuit winding motor 70 can be driven by delta connection.

[0057] like Figure 3As shown, the busbars 46U, 46V, and 46W of the first inverter 40 and the busbars 56U, 56V, and 56W of the second inverter 50, which are connected to the three-phase coils 72U, 72V, and 72W of the open-circuit winding motor 70, are configured such that the cross-sections are rectangular, and the busbars of the same phase (busbars 46U and 56U, busbars 46V and 56V, busbars 46W and 56W) face each other and are arranged in parallel with the long side of the cross-section, and the current flows in opposite directions. Busbars 46U, 46V, 46W and 56U, 56V, 56W are configured such that the distance between in-phase busbars (distance between busbars 46U and 56U, between busbars 46V and 56V, and between busbars 46W and 56W) is shorter than the distance between out-of-phase busbars (distance between a U-phase busbar and a V-phase busbar, a V-phase busbar and a W-phase busbar, and a W-phase busbar and a U-phase busbar). In other words, the distance between out-of-phase busbars is longer than the distance between in-phase busbars. This is to reduce the influence of magnetic flux generated by the current flowing through out-of-phase busbars. Furthermore, current sensors 64U, 64V, and 64W, which detect current by the intensity of magnetic flux, are positioned at the same distance from the in-phase busbars.

[0058] Figure 5 This diagram schematically illustrates the magnetic flux generated by busbars 46U, 46V, and 46W of the first inverter 40 and busbars 56U, 56V, and 56W of the second inverter 50. In the diagram, circular markers with black circles in the center indicate current flowing through the busbar from the back side to the surface, while circular markers with crosses indicate current flowing through the busbar from the surface to the back side. In the in-phase busbars (busbars 46U and 56U, busbars 46V and 56V, busbars 46W and 56W), the currents flow in opposite directions. Therefore, the magnetic flux generated by one of the in-phase busbars is canceled out by the flux generated by the other, resulting in a smaller overall magnetic flux generated by the in-phase busbars. Consequently, the magnetic flux generated by the in-phase busbars has a smaller effect on the out-of-phase busbars. On the other hand, the magnetic flux generated by each busbar in phase reinforces the other, thus the current sensors 64U, 64V, and 64W, positioned at the center of the in-phase busbars, can accurately detect the current flowing through them. Furthermore, as mentioned earlier, the magnetic flux generated by the in-phase busbars has little effect on the out-of-phase busbars; therefore, the influence of the out-of-phase magnetic flux is also reduced in the current sensors 64U, 64V, and 64W, improving detection accuracy.

[0059] In the power conversion device 30 described above, for the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50, the in-phase busbars are arranged in a parallel configuration with their cross-sectional surfaces facing each other in the long side direction and the current flowing in opposite directions. Therefore, the magnetic flux generated by the current flowing through each in-phase busbar cancels out on the outer periphery of each in-phase busbar, thus reducing the influence of the magnetic flux generated by the current flowing through each in-phase busbar on the out-of-phase busbars. Furthermore, the distance to the out-of-phase busbars is configured to be longer than the distance to the in-phase busbars, further reducing the influence of the magnetic flux generated by the current flowing through each in-phase busbar on the out-of-phase busbars. This also reduces the gap between the in-phase busbars. As a result, the power conversion device 30 can be miniaturized.

[0060] Furthermore, in the power conversion device 30 of the embodiment, the in-phase busbars are arranged parallel to each other with their cross-sections facing each other along the long side and the current flows in opposite directions. Current sensors 64U, 64V, and 64W are positioned at equal distances from the in-phase busbars. The magnetic flux generated by the current flowing through each in-phase busbar reinforces each other, thus the current sensors 64U, 64V, and 64W positioned between the in-phase busbars can accurately detect the current flowing through them. Of course, the magnetic flux generated by the in-phase busbars has little effect on the out-of-phase busbars, thus reducing the influence of the out-of-phase magnetic flux in the current sensors 64U, 64V, and 64W, further improving detection accuracy.

[0061] In the power conversion device 30 of the embodiment, each phase uses two pairs of transistors and two diodes connected in parallel as modules (two-in-one modules) for each phase, and six two-in-one modules are used to construct the first inverter 40 and the second inverter 50. However, as Figure 6 and Figure 7 As shown, the two pairs of transistors in each phase of the first inverter 40 and the two diodes connected in parallel therewith, and the two pairs of transistors in the same phase of the second inverter 50 and the two diodes connected in parallel therewith, can also be used as a module (a four-in-one module). Three four-in-one modules can then be used to construct the first inverter 40 and the second inverter 50. Additionally, as... Figure 8 and Figure 9 As shown, all transistors of the first inverter 40 and the diodes connected in parallel therewith, and all transistors of the second inverter 50 and the diodes connected in parallel therewith, can also be used as a single module (a 12-in-1 module), and the first inverter 40 and the second inverter 50 can be constructed using this single 12-in-1 module. Furthermore, as... Figure 10As shown, all the transistors of the first inverter 40 and the diodes connected in parallel with it can also be used as one module (six-in-one module), and all the transistors of the second inverter 50 and the diodes connected in parallel with it can be used as one module (six-in-one module). The first inverter 40 and the second inverter 50 can be constructed using two six-in-one modules.

[0062] In the power conversion device 30 of the embodiment, the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50 are made to have conductors directly exposed from the module, but they can also be made as follows: Figure 11 As shown in the modified example, except for the connection ends of the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50 to the three-phase coils 72U, 72V, 72W of the open-circuit winding motor 70, they are covered by insulating coverings 47U, 47V, 47W, 57U, 57V, 57W formed of insulating material. In this case, short circuits between terminals caused by the intrusion of foreign matter can be prevented more reliably. Furthermore, as... Figure 12 As shown in the modified example, partition walls 66U, 66V, 66W made of insulating material can also be installed between the in-phase busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50. In this case, short circuits between terminals caused by the intrusion of foreign matter can be prevented more reliably.

[0063] In the power conversion device 30 of the embodiment, a connection switch 60p is installed between the first inverter 40 and the second inverter 50 on the positive side power line 24p, and a connection switch 60n is installed between the first inverter 40 and the second inverter 50 on the negative side power line 24n. However, it is acceptable not to install one or both of the connection switches 60p and 60n. If the connection switch 60n is not installed between the first inverter 40 and the second inverter 50 on the negative side power line 24n, as... Figure 13 and Figure 14 As shown, regarding the negative side connection terminals 44U, 44V, 44W of the first inverter 40 and the negative side connection terminals 54U, 54V, 54W of the second inverter 50, the negative side connection terminals of the same phase can also be used as common negative side connection terminals 4454U, 4454V, 4454W. Furthermore, if no connection switch 60p is installed between the first inverter 40 and the second inverter 50 on the positive side power line 24p, as... Figure 15 and Figure 16As shown, regarding the positive side connection terminals 42U, 42V, 42W of the first inverter 40 and the positive side connection terminals 52U, 52V, 52W of the second inverter 50, the positive side connection terminals of the same phase can also be used as common positive side connection terminals 4252U, 4252V, 4252V. Furthermore, if no connection switch 60p, 60n is installed between the first inverter 40 and the second inverter 50 with positive side power line 24p and negative side power line 24n, as... Figure 17 and Figure 18 As shown, it is also possible that, for the positive side connection terminals 42U, 42V, 42W of the first inverter 40 and the positive side connection terminals 52U, 52V, 52W of the second inverter 50, the positive side connection terminals of the same phase are used as common positive side connection terminals 4252U, 4252V, 4252V. Furthermore, for the negative side connection terminals 44U, 44V, 44W of the first inverter 40 and the negative side connection terminals 54U, 54V, 54W of the second inverter 50, the negative side connection terminals of the same phase are used as common negative side connection terminals 4454U, 4454V, 4454W.

[0064] In the power conversion device 30 of the embodiment, such as Figure 5 As shown, the configuration is as follows: the long-side faces of the busbars 46U, 46V, and 46W of the first inverter 40 are arranged in the same plane, and the long-side faces of the busbars 56U, 56V, and 56W of the second inverter 50 are arranged in the same plane, and the long-side faces of the busbars of the same phase face each other. However, as Figure 19 As shown in the modified example, it can also be configured such that the long side faces of the cross-sections of the same-phase busbars face each other, and the long side faces of the cross-sections of the different-phase busbars face each other. Additionally, as... Figure 20 As shown, it can also be configured such that the long side surfaces of the cross sections of the busbars 46U, 46V, and 46W of the first inverter 40 are arranged in the same plane, and the long side surfaces of the cross sections of the busbars 56U, 56V, and 56W of the second inverter 50 are arranged in the same plane. Furthermore, the long side surfaces of all the cross sections of the busbars 46U, 46V, and 46W of the first inverter 40 and the busbars 56U, 56V, and 56W of the second inverter 50 are arranged in the same plane.

[0065] In the power conversion device 30 of the embodiment, current sensors 64U, 64V, 64W are arranged in the center of the in-phase busbars between the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50. However, the positions of the current sensors 64U, 64V, 64W only need to be at the same distance from the in-phase busbars between them, so as... Figures 21-23 As shown, current sensors 64U, 64V, and 64W can also be positioned at a central offset location, equidistant from the same busbar in phase.

[0066] In the power conversion device 30 of the embodiment, current sensors 64U, 64V, 64W are arranged in the center of the in-phase busbars between the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50. However, as Figure 24 As shown in the modified example, recesses can also be formed on the facing surfaces of the in-phase busbars 46U, 46V, 46W in the first inverter 40 and 56U, 56V, 56W in the second inverter 50, and the current sensors 64U, 64V, 64W can be arranged to be embedded in the center of the recesses of the in-phase busbars. In this way, the intensity of the magnetic flux that is mutually enhanced by the current flowing through each in-phase busbar is increased, thus further improving the detection accuracy of the current sensors 64U, 64V, 64W.

[0067] In the power conversion device 30 of this embodiment, current sensors 64U, 64V, 64W are disposed at the center of the in-phase busbars between the busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50. However, magnetic cores 68U, 68V, 68W may also be used to cover the area around the in-phase busbars 46U, 46V, 46W of the first inverter 40 and the busbars 56U, 56V, 56W of the second inverter 50. In this case, it is preferable that the magnetic cores 68U, 68V, 68W are formed to have open ends near the current sensors 64U, 64V, 64W. This increases the strength of the magnetic flux that mutually reinforces each other through the current flowing through the in-phase busbars, thereby further improving the detection accuracy of the current sensors 64U, 64V, 64W.

[0068] The correspondence between the main elements of the implementation method and the main elements of the invention listed in the solution to the problem section will be explained. In the implementation method, the open-circuit winding motor 70 corresponds to "open-circuit winding motor", the three-phase coils 72U, 72V, and 72W correspond to "three-phase winding", the first inverter 40 corresponds to "first inverter", the second inverter 50 corresponds to "second inverter", the busbars 46U, 46V, and 46W of the first inverter 40 correspond to "first conductor of the three phases", and the busbars 56U, 56V, and 56W of the second inverter 50 correspond to "second conductor of the three phases".

[0069] It should be noted that the correspondence between the main elements of the implementation method and the main elements of the invention described in the "Solution to the Problem" column is merely an example of how the implementation method is used to carry out the invention described in the "Solution to the Problem" column, and therefore does not limit the elements of the invention described in the "Solution to the Problem" column. That is, the interpretation of the invention described in the "Solution to the Problem" column should be based on the description in that column, and the implementation method is merely a specific example of the invention described in the "Solution to the Problem" column.

[0070] The present disclosure has been described above using various embodiments. However, the present disclosure is not limited to such embodiments in any way, and can of course be implemented in various ways without departing from the spirit of the present disclosure.

[0071] Industrial availability

[0072] This disclosure can be applied to industries such as the manufacture of power conversion devices.

Claims

1. A power conversion device comprising a first inverter connected to one end of a three-phase winding of an open-circuit winding motor and a second inverter connected to the other end of the three-phase winding, characterized in that it comprises: The first conductor of the three phases connects one end of each phase of the three-phase winding to each phase of the first inverter; and The second conductor of the three phases connects the other end of each phase of the three-phase winding to each phase of the second inverter. The phases of the first conductor and the phases of the second conductor are arranged such that conductors of the same phase are parallel and the current flows in opposite directions.

2. The power conversion device according to claim 1, wherein, The cross-sections of the first conductor and the second conductor are rectangular. The phases of the first conductor and the phases of the second conductor are arranged such that conductors of the same phase face each other or are on the same plane.

3. The power conversion device according to claim 1, wherein, The phases of the first conductor and the phases of the second conductor are arranged such that the distance between conductors of the same phase is shorter than the distance between conductors of different phases.

4. The power conversion device according to claim 1, wherein, An insulating wall is provided between the first conductor and the second conductor, which are in phase.

5. The power conversion device according to claim 1, wherein, Each phase of the first conductor and each phase of the second conductor are respectively covered with insulating material.

6. The power conversion device according to claim 1, wherein, At least one of the positive or negative side of the same phase of the connection terminals of each phase of the first inverter and the connection terminals of each phase of the second inverter constitutes a common terminal.

7. The power conversion device according to claim 1, wherein, At least one of the positive or negative side lines connecting the first inverter and the second inverter has a switch for connecting and disconnecting.

8. The power conversion device according to any one of claims 1 to 7, wherein, The device is equipped with a three-phase current sensor, which is positioned at the same distance from the conductor of the same phase between each phase of the first conductor and each phase of the second conductor.

9. The power conversion device according to claim 8, wherein, The three-phase current sensors are arranged between conductors of the same phase.

10. The power conversion device according to claim 9, wherein, Each phase of the first conductor and each phase of the second conductor have recesses formed on opposite surfaces of the conductors of the same phase. The three-phase current sensors are configured to fit into the recesses of conductors of the same phase.

11. The power conversion device according to claim 9, wherein, A magnetic core with an open end is disposed around each phase of the first conductor and each phase of the second conductor near the current sensor of the three phases.

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