Drive unit

Abstract

To provide a drive device capable of obtaining a larger output than a conventional one.SOLUTION: A drive device according to the present invention includes a three-phase electric motor 1 having a stator 15 provided with stator windings, and first and second inverters 3 and 5. The first to third stator windings 11, 12, and 13 are electrically separated from the other stator windings. The U phase, V phase, and W phase of the three-phase alternating current from the first inverter 3 are electrically connected to first terminals 11a, 12a, and 13a of the first to third stator windings 11, 12, and 13, and the U phase, V phase, and W phase of three-phase alternating current from the second inverter 5 are electrically connected to a second terminal 13b of the third stator winding 13, a second 11b of the first stator winding 11, and a second terminal 12b of the second stator winding 12. The first and second inverters 3 and 5 are configured to be able to supply three-phase alternating current whose phases are shifted from each other by π / 3.SELECTED DRAWING: Figure 3

Description

Technical Field

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[0001] The present invention relates to a drive device including a three-phase motor.

Background Art

[0002] As a power source for electric vehicles and hybrid electric vehicles, a three-phase motor such as a three-phase induction motor is used. As a conventional three-phase induction motor, for example, those described in Patent Documents 1 and 2 below are known. Patent Documents 1 and 2 disclose that a three-phase motor includes a stator winding having 6 lead terminals in 3 phases, is driven by two three-phase inverters, and in a low-speed operation range within the rated output range of this motor and at a rotational speed below a predetermined rotational speed, control is performed to make the outputs of both inverters in the same phase, and in a high-speed operation range exceeding the predetermined rotational speed, the output phase of one inverter is inverted by 180 degrees.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0005] This invention has been made in view of the above-mentioned problems, and aims to provide a drive device equipped with a three-phase motor that can achieve a larger output than conventional devices. [Means for solving the problem]

[0006] To solve the above-mentioned problems, the drive device according to the present invention comprises a three-phase motor having a stator provided with three-phase stator windings, and a first inverter and a second inverter for supplying three-phase power, wherein the first stator winding, the second stator winding, and the third stator winding of the three-phase stator windings are provided within the stator such that they are electrically separated from the other stator windings when not connected to the first inverter and the second inverter, respectively, and the U-phase, V-phase, and The W phase is configured to be electrically connectable to the first terminal of the first stator winding, the first terminal of the second stator winding, and the first terminal of the third stator winding, respectively. The U, V, and W phases of the three-phase AC supplied from the second inverter are configured to be electrically connectable to the second terminal of the third stator winding, the second terminal of the first stator winding, and the second terminal of the second stator winding, respectively. The first and second inverters are configured to supply three-phase AC at the same frequency but with a phase difference of π / 3 from each other.

[0007] According to the drive device of the present invention, it is possible to supply alternating current to the first terminal of each stator winding with a first inverter and to supply alternating current to the second terminal of each stator winding with a second inverter. In this case, since these alternating currents are in opposite phase, the current flowing through each stator winding becomes zero on average over time. Furthermore, in the stator, the first, second, and third stator windings of the three-phase stator windings are electrically separated from each other when not connected to the first and second inverters, and the connections between the first to third stator windings and the first and second inverters are configured such that each phase of the three-phase alternating current is independent, that is, the first to third stator windings are circuit-independent of each other. Therefore, in this connection, the three-phase AC voltage is not divided between the first to third stator windings, the three-phase AC current is not divided due to circuit branching, and no closed circuits are formed. As a result, it becomes possible to obtain a larger output than before.

[0008] Furthermore, the drive device according to the present invention may further include a switch for reversibly changing the connection state between the first stator winding, the second stator winding, and the third stator winding and the first inverter and the second inverter between a first connection state, a second connection state and a third connection state, wherein in the first connection state, the first stator winding, the second stator winding, and the third stator winding are star-connected to the first inverter or the second inverter, and in the second connection state, the first stator winding, the second stator winding, and the third stator winding are star-connected to the first inverter or the second inverter. The sub-winding is delta-connected to the first inverter or the second inverter. In the third connection state, the U, V, and W phases of the three-phase AC supplied from the first inverter are electrically connected to the first terminal of the first stator winding, the first terminal of the second stator winding, and the first terminal of the third stator winding, respectively. The U, V, and W phases of the three-phase AC supplied from the second inverter are electrically connected to the second terminal of the third stator winding, the second terminal of the first stator winding, and the second terminal of the second stator winding, respectively.

[0009] As a result, the connection state between the first stator winding, the second stator winding, and the third stator winding and the first inverter and the second inverter can be reversibly changed to any of the first, second, or third connection states simply by switching operations using the switch. [Effects of the Invention]

[0010] According to the present invention, a drive system is provided that includes a three-phase motor capable of obtaining a larger output than conventional systems. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the configuration of a drive device according to an embodiment of the present invention. [Figure 2] This figure shows an example of the circuit configuration of the first inverter and the second inverter. [Figure 3] This diagram shows the detailed circuit configuration of the switch and the three-phase motor. [Figure 4] This figure shows examples of three-phase AC current waveforms supplied by the first and second inverters. [Figure 5] This diagram shows the wiring configuration of the first stator winding, the second stator winding, and the third stator winding in the first wiring configuration. [Figure 6] This diagram shows the wiring configuration of the first stator winding, the second stator winding, and the third stator winding in the second wiring configuration. [Figure 7] This diagram shows the wiring configuration of the first stator winding, the second stator winding, and the third stator winding in the third wiring configuration. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the attached drawings. In each drawing, the same reference numerals are used for the same elements where possible. Furthermore, the dimensional ratios within and between components in the drawings are arbitrary for the sake of readability.

[0013] Figure 1 is a schematic diagram showing the configuration of a drive device according to an embodiment of the present invention. As shown in Figure 1, the drive device D of this embodiment comprises a three-phase motor 1, a first inverter 3, a second inverter 5, a switch 7, and a control unit 9.

[0014] The three-phase motor 1 is an electric motor that operates using three-phase power, and is, for example, an induction motor or a synchronous motor. The three-phase motor 1 is used, for example, as a power source for electric vehicles and hybrid electric vehicles.

[0015] The first inverter 3 and the second inverter 5 are three-phase inverters each having a function of converting DC input from a DC power supply V into three-phase AC of a predetermined mode and outputting it. The control unit 9 controls operations and the like based on the functions of the first inverter 3 and the second inverter 5. The switch 7 is configured such that the three-phase AC output from the first inverter 3 and the second inverter 5 can be supplied to the three-phase motor 1 via the switch 7. The DC power supply V is, for example, a DC battery mounted on an electric vehicle or a hybrid electric vehicle. The DC power supply V is electrically connected to the first inverter 3 and the second inverter 5 and supplies a DC current to these.

[0016] FIG. 2 is a diagram showing an example of the circuit configuration of the first inverter and the second inverter. The first inverter 3 and the second inverter 5 each have six pairs of transistors and diodes connected in parallel, and as shown in FIG. 2, between an upper wiring connected to the positive electrode of the DC power supply V and a lower wiring connected to the negative electrode of the DC power supply V, two pairs of the pairs are connected in series.

[0017] The first inverter 3 has a U-phase output terminal 3U, a V-phase output terminal 3V, and a W-phase output terminal 3W. The U-phase output terminal 3U, the V-phase output terminal 3V, and the W-phase output terminal 3W are each connected between two pairs of transistors and diodes connected between the upper wiring and the lower wiring. Similarly, the second inverter 5 has a U-phase output terminal 5U, a V-phase output terminal 5V, and a W-phase output terminal 5W. The U-phase output terminal 3U, the V-phase output terminal 3V, and the W-phase output terminal 3W are each connected between two pairs of transistors and diodes connected between the upper wiring and the lower wiring.

[0018] As these transistors, power transistors can be used. By appropriately controlling the on / off of these transistors with a control unit 9 (see FIG. 1), the first inverter 3 and the second inverter 5 can output three-phase currents. The first inverter 3 outputs the U-phase of the three-phase AC from the U-phase output terminal 3U, the V-phase of the three-phase AC from the V-phase output terminal 3V, and the W-phase of the three-phase AC from the W-phase output terminal 3W. Similarly, the second inverter 5 outputs the U-phase of the three-phase AC from the U-phase output terminal 5U, the V-phase of the three-phase AC from the V-phase output terminal 5V, and the W-phase of the three-phase AC from the W-phase output terminal 5W.

[0019] FIG. 3 is a diagram showing the details of the circuit configuration of the switch and the three-phase motor. As shown in FIG. 3, the switch 7 has U-phase input terminals 7U1, V-phase input terminals 7V1, and W-phase input terminals 7W1, which are respectively connected to the U-phase output terminal 3U, the V-phase output terminal 3V, and the W-phase output terminal 3W of the first inverter 3. Also, the switch 7 has U-phase input terminals 7U2, V-phase input terminals 7V2, and W-phase input terminals 7W2, which are respectively connected to the U-phase output terminal 5U, the V-phase output terminal 5V, and the W-phase output terminal 5W of the second inverter 5.

[0020] In addition, the switch 7 has six output terminals 7a, 7b, 7c, 7d, 7e, 7f. The U-phase input terminal 7U2 is connected to the output terminal 7f by a wiring E1, the W-phase input terminal 7W2 is connected to the output terminal 7e by a wiring E2, and the V-phase input terminal 7V2 is connected to the output terminal 7d by a wiring E3. The wiring E2 is connected to the output terminal 7c by a wiring E5 via a switch S1, the wiring E3 is connected to the output terminal 7b by a wiring E6 via a switch S2, and the wiring E1 is connected to the output terminal 7a by a wiring E4 via a switch S3.

[0021] Furthermore, the W-phase input terminal 7W1 is connected to wiring E5 via wiring E7 through switches S4 and S7, the V-phase input terminal 7V1 is connected to wiring E6 via wiring E8 through switches S5 and S8, and the U-phase input terminal 7U1 is connected to wiring E4 via wiring E9 through switches S6 and S9. Additionally, a switch S10 is provided between wiring E7 and wiring E8, and a switch S11 is provided between wiring E8 and wiring E9.

[0022] The three-phase motor 1 has a stator 15 on which three-phase stator windings are provided. The three-phase stator windings include a first stator winding 11, a second stator winding 12, and a third stator winding 13. The first stator winding 11, the second stator winding 12, and the third stator winding 13 are provided in the stator 15 with a phase difference of 120° from each other so as to generate a rotating magnetic field for rotating a rotor (not shown) in the stator 15 when three-phase AC power is supplied.

[0023] The first stator winding 11, the second stator winding 12, and the third stator winding 13 are provided within the stator 15 so as to be electrically separated from the other stator windings when they are not connected to the first inverter 3 and the second inverter 5, respectively. That is, the pair of terminals of the first stator winding 11 (first terminal 11a and second terminal 11b), the pair of terminals of the second stator winding 12 (first terminal 12a and second terminal 12b), and the pair of terminals of the third stator winding 13 (first terminal 13a and second terminal 13b) are not electrically connected to each other when viewed solely from the perspective of the components of the stator 15. Such electrical separation can be achieved, for example, by providing a physical gap or insulating material between the pair of terminals of each stator winding and the pair of terminals of the other stator windings.

[0024] Each pair of terminals of the stator winding is connected to one of the six output terminals 7a, 7b, 7c, 7d, 7e, or 7f of the switch 7. Specifically, the first terminal 11a of the first stator winding 11 is connected to output terminal 7a of the switch 7, the second terminal 11b of the first stator winding 11 is connected to output terminal 7d of the switch 7, the first terminal 12a of the second stator winding 12 is connected to output terminal 7b of the switch 7, the second terminal 12b of the second stator winding 12 is connected to output terminal 7e of the switch 7, the first terminal 13a of the third stator winding 13 is connected to output terminal 7c of the switch 7, and the second terminal 13b of the third stator winding 13 is connected to output terminal 7f of the switch 7.

[0025] The first inverter 3 and the second inverter 5 in Figure 1 are configured to supply three-phase alternating current at the same frequency but with a phase difference of π / 3 from each other. Figure 4 shows examples of current waveforms of the three-phase alternating current supplied by the first and second inverters in such a case. Figure 4(a) shows the three-phase alternating current supplied by the first inverter 3, where the waveform shown by the solid line represents the U-phase current I3U output from the U-phase output terminal 3U (see Figure 1), the waveform shown by the dashed line represents the V-phase current I3V output from the V-phase output terminal 3V (see Figure 1), and the waveform shown by the dashed line represents the W-phase current I3W output from the W-phase output terminal 3W (see Figure 1).

[0026] Furthermore, Figure 4(b) shows the three-phase AC supplied by the second inverter 5 at the same timing as the first inverter 3 in Figure 4(a). The waveform shown by the solid line represents the U-phase current I5U output from the U-phase output terminal 5U (see Figure 1), the waveform shown by the dashed line represents the V-phase current I5V output from the V-phase output terminal 5V (see Figure 1), and the waveform shown by the dashed line represents the W-phase current I5W output from the W-phase output terminal 5W (see Figure 1). In this embodiment, as shown in Figure 4, the phase of the three-phase current supplied from the second inverter 5 leads the phase of the three-phase current supplied from the first inverter 3 by π / 3.

[0027] The switch 7 shown in Figure 3 has the function of reversibly changing the connection state between the first stator winding 11, the second stator winding 12, and the third stator winding 13 and the first inverter 3 and the second inverter 5 between the first connection state, the second connection state, and the third connection state by switching the switches S1 to S11 on and off.

[0028] (First wiring configuration, star connection) In the first wiring configuration, switches S1, S2, S3, S4, S5, and S6 of the changeover switch 7 shown in Figure 3 are turned off, and switches S7, S8, S9, S10, and S11 are turned on. Figure 5 shows the wiring configuration of the first stator winding, the second stator winding, and the third stator winding in the first wiring configuration. As shown in Figure 5, in this configuration, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are connected in a star configuration to the second inverter 5.

[0029] Specifically, the first terminal 11a of the first stator winding 11, the first terminal 12a of the second stator winding 12, and the first terminal 13a of the third stator winding 13 are electrically connected, so that the output terminals 7a, 7b, and 7c become the neutral point. The second terminal 11b of the first stator winding 11 is electrically connected to the V-phase output terminal 5V of the second inverter 5 via the output terminal 7d and the V-phase input terminal 7V2, and is therefore electrically connected to the V-phase supplied from the second inverter 5. The second terminal 12b of the second stator winding 12 is electrically connected to the W-phase output terminal 5W of the second inverter 5 via the output terminal 7e and the W-phase input terminal 7W2, and is therefore electrically connected to the W-phase supplied from the second inverter 5. The second terminal 13b of the third stator winding 13 is electrically connected to the U-phase output terminal 5U of the second inverter 5 via the output terminal 7f and the U-phase input terminal 7U2, and is therefore electrically connected to the U-phase supplied from the second inverter 5.

[0030] In this way, in the first wiring configuration, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are connected in a star configuration to the second inverter 5, and the three-phase motor 1 can be operated by supplying three-phase AC power from the second inverter 5 to the first stator winding 11, the second stator winding 12, and the third stator winding 13.

[0031] (Second wiring configuration, delta connection) In the second wiring configuration, switches S1, S2, and S3 of the switch 7 shown in Figure 3 are turned ON, and switches S4, S5, S6, S7, S8, S9, S10, and S11 are turned OFF. Figure 6 shows the wiring configuration of the first stator winding, the second stator winding, and the third stator winding in the second wiring configuration. As shown in Figure 6, in this configuration, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are delta-connected to the second inverter 5.

[0032] Specifically, the first terminal 11a of the first stator winding 11 and the second terminal 13b of the third stator winding 13 are electrically connected to each other and electrically connected to the U-phase output terminal 5U of the second inverter 5 via output terminals 7a, 7f and U-phase input terminal 7U2, thereby electrically connected to the U-phase supplied from the second inverter 5. In addition, the second terminal 11b of the first stator winding 11 and the first terminal 12a of the second stator winding 12 are electrically connected to each other and electrically connected to the V-phase output terminal 5V of the second inverter 5 via output terminals 7b, 7d and V-phase input terminal 7V2, thereby electrically connected to the V-phase supplied from the second inverter 5. Furthermore, the second terminal 12b of the second stator winding 12 and the first terminal 13a of the third stator winding 13 are electrically connected to each other and electrically connected to the W-phase output terminal 5W of the second inverter 5 via the output terminals 7c, 7e and the W-phase input terminal 7W2, thereby electrically connected to the W-phase supplied from the second inverter 5.

[0033] In this way, in the second connection state, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are delta-connected to the second inverter 5, and the three-phase motor 1 can be operated by supplying three-phase AC power from the second inverter 5 to the first stator winding 11, the second stator winding 12, and the third stator winding 13.

[0034] (Third wiring configuration, split connection) In the second wiring state, switches S1, S2, S3, S10, and S11 of the changeover switch 7 shown in Figure 3 are turned off, and switches S4, S5, S6, S7, S8, and S9 are turned on. Figure 7 shows the wiring state of the first stator winding, the second stator winding, and the third stator winding in the third wiring state. As shown in Figure 7, in this wiring state, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are connected to the second inverter 5 in a manner referred to as a split connection in this specification.

[0035] Specifically, the first terminal 11a of the first stator winding 11 is electrically connected to the U-phase output terminal 3U of the first inverter 3 via the output terminal 7a and the U-phase input terminal 7U1, and is therefore electrically connected to the U-phase supplied from the first inverter 3. In addition, the second terminal 11b of the first stator winding 11 is electrically connected to the V-phase output terminal 5V of the second inverter 5 via the output terminal 7d and the V-phase input terminal 7V2, and is therefore electrically connected to the V-phase supplied from the second inverter 5.

[0036] Furthermore, the first terminal 12a of the second stator winding 12 is electrically connected to the V-phase output terminal 3V of the first inverter 3 via the output terminal 7b and the V-phase input terminal 7V1, and is therefore electrically connected to the V-phase supplied from the first inverter 3. Also, the second terminal 12b of the second stator winding 12 is electrically connected to the W-phase output terminal 5W of the second inverter 5 via the output terminal 7e and the W-phase input terminal 7W2, and is therefore electrically connected to the W-phase supplied from the second inverter 5.

[0037] Furthermore, the first terminal 13a of the third stator winding 13 is electrically connected to the W-phase output terminal 3W of the first inverter 3 via the output terminal 7c and the W-phase input terminal 7W1, and is therefore electrically connected to the W-phase supplied from the first inverter 3. Also, the second terminal 13b of the third stator winding 13 is electrically connected to the U-phase output terminal 5U of the second inverter 5 via the output terminal 7f and the U-phase input terminal 7U2, and is therefore electrically connected to the U-phase supplied from the second inverter 5.

[0038] Therefore, U-phase AC is supplied from the first inverter 3 to the first terminal 11a of the first stator winding 11, V-phase AC is supplied from the second inverter 5 to the second terminal 11b of the first stator winding 11, V-phase AC is supplied from the first inverter 3 to the first terminal 12a of the second stator winding 12, W-phase AC is supplied from the second inverter 5 to the second terminal 12b of the second stator winding 12, W-phase AC is supplied from the first inverter 3 to the first terminal 13a of the third stator winding 13, and U-phase AC is supplied from the second inverter 5 to the second terminal 13b of the third stator winding 13.

[0039] In the third connection state, the first inverter 3 and the second inverter 5 supply three-phase alternating current of the same amplitude and frequency to the first stator winding 11, the second stator winding 12, and the third stator winding 13. However, the phase of the three-phase current supplied from the second inverter 5 leads the phase of the three-phase current supplied from the first inverter 3 by π / 3 (see Figure 4). Therefore, alternating currents with opposite phases are applied to the first and second terminals of each stator winding. For example, as described above, U-phase AC is supplied from the first inverter 3 to the first terminal 11a of the first stator winding 11, and V-phase AC is supplied from the second inverter 5 to the second terminal 11b of the first stator winding 11. However, the V-phase is 120° ahead in phase of the U-phase, and the phase of the three-phase current supplied from the second inverter 5 is π / 3 ahead of the phase of the three-phase current supplied from the first inverter 3. Therefore, the phase difference between these AC currents is 180°. The same applies to the second stator winding 12 and the third stator winding 13.

[0040] In this way, in the third wiring configuration, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are split-connected to the second inverter 5, allowing the three-phase motor 1 to be operated.

[0041] According to the drive device D of this embodiment described above, by setting the wiring to a third configuration, it is possible to supply alternating current to the first terminals 11a, 12a, and 13a of each stator winding 11, 12, and 13 with the first inverter 3, and to supply alternating current to the second terminals 11b, 12b, and 13b of each stator winding 11, 12, and 13 with the second inverter 5. In this case, since these alternating currents are in opposite phase, the current flowing through each stator winding 11, 12, and 13 becomes 0 on average over time (see Figures 4 and 7).

[0042] Furthermore, in the stator 15, the first stator winding 11, the second stator winding 12, and the third stator winding 13 are electrically separated from each other when not connected to the first inverter 3 and the second inverter 5. In addition, the connections between the first to third stator windings 11, 12, and 13 and the first and second inverters 3 and 5 are configured so that each phase of the three-phase AC is independent, that is, the first to third stator windings 11, 12, and 13 are circuit-independent of each other (see Figure 7). As a result, in this connection, the voltage of the three-phase AC is not divided between the lines of the first to third stator windings 11, 12, and 13, nor is the current of the three-phase AC divided due to circuit branching, nor is a closed circuit formed. As a result, it is possible to obtain a larger output than in the conventional method. Specifically, if the DC voltage and current input to the inverter are V (V) and I (A), respectively, and the power factor is cosθ, then the power P of the first stator winding 11, the second stator winding 12, and the third stator winding 13 in the first connection state (star connection) and the second connection state (delta connection) is √3VIcosθ (W), whereas the power P of the first stator winding 11, the second stator winding 12, and the third stator winding 13 in the third connection state (split connection) is 3VIcosθ (W).

[0043] Furthermore, the drive unit D according to this embodiment, as described above, is equipped with a switch 7 as described above (see Figure 7). This allows the connection state between the first stator winding 11, the second stator winding 12, and the third stator winding 13 and the first inverter 3 and the second inverter 5 to be reversibly changed to one of the first connection state (star connection), the second connection state (delta connection), or the third connection state (split connection) simply by switching operations of the switch 7.

[0044] The present invention is not limited to the embodiments described above, and various modifications are possible.

[0045] For example, in the above embodiment, in the first connection state (star connection), the first stator winding 11, the second stator winding 12, and the third stator winding 13 are connected in a star configuration with the second inverter 5 (see Figure 7). In addition, the switch 7 may be configured so that the first stator winding 11, the second stator winding 12, and the third stator winding 13 can be connected in a star configuration with the first inverter 3. In this case, even if one of the first inverter 3 and the second inverter 5 fails, the three-phase motor 1 can be operated by connecting the other inverter in a star configuration with the first stator winding 11, the second stator winding 12, and the third stator winding 13.

[0046] Furthermore, in the above-described embodiment, in the second connection state (delta connection), the first stator winding 11, the second stator winding 12, and the third stator winding 13 are delta connected to the second inverter 5 (see Figure 7). In addition, the switch 7 may be configured so that the first stator winding 11, the second stator winding 12, and the third stator winding 13 are delta connected to the first inverter 3. In this case, even if one of the first inverter 3 and the second inverter 5 fails, the three-phase motor 1 can be operated by delta connecting the other inverter to the first stator winding 11, the second stator winding 12, and the third stator winding 13.

[0047] Furthermore, in the above-described embodiment, in the third connection state (split connection), the phase of the three-phase current supplied from the second inverter 5 leads the phase of the three-phase current supplied from the first inverter 3 by π / 3 (see Figure 4), but the phase of the three-phase current supplied from the second inverter 5 may lag behind the phase of the three-phase current supplied from the first inverter 3 by π / 3. [Explanation of Symbols]

[0048] 1...Three-phase motor, 3...First inverter, 5...Second inverter, 7...Switch, 11...First stator winding, 11a...First terminal of the first stator winding, 11b...Second terminal of the first stator winding, 12...Second stator winding, 12a...First terminal of the second stator winding, 12b...Second terminal of the second stator winding, 13...Third stator winding, 13a...First terminal of the third stator winding, 13b...Second terminal of the third stator winding, 15...Stator.

Claims

1. A three-phase motor having a stator equipped with three-phase stator windings, A first inverter and a second inverter for supplying three-phase power, A drive device equipped with, The first, second, and third stator windings of the three-phase stator winding are provided within the stator such that they are electrically separated from the other stator windings when they are not connected to the first and second inverters, respectively. The U-phase, V-phase, and W-phase of the three-phase AC supplied from the first inverter are configured to be electrically connectable to the first terminal of the first stator winding, the first terminal of the second stator winding, and the first terminal of the third stator winding, respectively. The U-phase, V-phase, and W-phase of the three-phase AC supplied from the second inverter are configured to be electrically connectable to the second terminal of the third stator winding, the second terminal of the first stator winding, and the second terminal of the second stator winding, respectively. The first inverter and the second inverter are configured to supply three-phase alternating current of the same frequency, and the phase of the three-phase alternating current supplied from the second inverter is π / 3 ahead of the phase of the three-phase alternating current supplied from the first inverter. A drive device in which the U-phase, V-phase, and W-phase of three-phase AC supplied from the first inverter are electrically connected to the first terminal of the first stator winding, the first terminal of the second stator winding, and the first terminal of the third stator winding, respectively, and the U-phase, V-phase, and W-phase of three-phase AC supplied from the second inverter are electrically connected to the second terminal of the third stator winding, the second terminal of the first stator winding, and the second terminal of the second stator winding, respectively, and in which case AC currents with opposite phases are applied to the first and second terminals of the first stator winding, the second stator winding, and the third stator winding.

2. A three-phase motor having a stator provided with three-phase stator windings, A first inverter and a second inverter for supplying three-phase power, A drive device equipped with, The first, second, and third stator windings of the three-phase stator winding are provided within the stator such that they are electrically separated from the other stator windings when they are not connected to the first and second inverters, respectively. The U-phase, V-phase, and W-phase of the three-phase AC supplied from the first inverter are configured to be electrically connectable to the first terminal of the first stator winding, the first terminal of the second stator winding, and the first terminal of the third stator winding, respectively. The U-phase, V-phase, and W-phase of the three-phase AC supplied from the second inverter are configured to be electrically connectable to the second terminal of the third stator winding, the second terminal of the first stator winding, and the second terminal of the second stator winding, respectively. The first inverter and the second inverter are configured to supply three-phase alternating current at the same frequency and with a phase difference of π / 3 from each other. The drive device further includes a switch for reversibly changing the connection state between the first stator winding, the second stator winding, and the third stator winding and the first inverter and the second inverter between a first connection state, a second connection state, and a third connection state. In the first wiring configuration, the first stator winding, the second stator winding, and the third stator winding are star-connected to the first inverter or the second inverter. In the second wiring configuration, the first stator winding, the second stator winding, and the third stator winding are delta-connected to the first inverter or the second inverter. In the third wiring configuration, the U, V, and W phases of the three-phase AC power supplied from the first inverter are electrically connected to the first terminal of the first stator winding, the first terminal of the second stator winding, and the first terminal of the third stator winding, respectively, and the U, V, and W phases of the three-phase AC power supplied from the second inverter are electrically connected to the second terminal of the third stator winding, the second terminal of the first stator winding, and the second terminal of the second stator winding, respectively, in the drive device.

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