AC motor switching device

Abstract

To increase the number of operating patterns for an AC electric motor.SOLUTION: An AC electric motor switching device 10 controls the switching of an AC electric motor 4. The AC electric motor switching device 10 has a switching unit 20 that switches the connecting states of windings 71, 72, 73 of a plurality of phases. The switching unit 20 switches between a first state, a second state, and a third state. The first state is a state in which the current flow control to each of first windings 71A, 72A, 73A of each phase is allowed and the current flow control to each of second windings 71B, 72B, 73B is shut off. The second state is a state in which the current flow control to each of the second windings 71B, 72B, 73B of each phase is allowed and the current flow control to each of the first windings 71A, 72A, 73A is shut off. The third state is a state in which the current flow control to the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B is allowed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a switching device for an AC motor. [Background technology]

[0002] In the AC motor disclosed in Patent Document 1, each phase winding is made up of multiple windings, and connecting terminals that connect the multiple windings together and both terminals of each phase winding are provided outside the motor. The winding switching device includes winding switching means that appropriately switches the connecting terminals, and a variable frequency power supply that supplies a variable voltage with a variable frequency to the AC motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-111492 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, the winding of each phase of an AC motor is divided into multiple regions, and the operation state can be switched between using only a partial region of each phase winding and using other regions as well. However, the technology disclosed in Patent Document 1 requires the partial region of each phase to be used in switching the connection state of the winding of each phase, which limits the operating patterns.

[0005] An object of the present disclosure is to provide a technique that makes it easy to increase the number of operating patterns of an AC motor. [Means for solving the problem]

[0006] The switching device for an AC motor according to the present disclosure includes: 1. A switching device for switching connection states of windings of an AC motor having a plurality of phases, each phase having a first winding and a second winding, a switching unit for switching the connection state of the windings of the plurality of phases; The switching unit switches between a first state in which current control is permitted for the first winding of each of the windings of each phase and current control is blocked for each of the second windings of each of the windings of each phase, a second state in which current control is permitted for the second winding of each of the windings of each phase and current control is blocked for each of the first windings, and a third state in which current control is permitted for the first winding and the second winding of each of the windings of each of the windings of each phase. [Effects of the Invention]

[0007] The technology according to the present disclosure can increase the number of operating patterns of an AC motor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a circuit diagram that schematically illustrates an in-vehicle system that includes a switching device for an AC motor according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram illustrating the correspondence between the states of the switching units in the switching device for the AC motor according to the first embodiment and the windings to be energized. [Figure 3] FIG. 3 is an explanatory diagram illustrating a first state of the switching device for the AC motor shown in FIG. [Figure 4] FIG. 4 is an explanatory diagram illustrating a second state of the switching device for the AC motor shown in FIG. [Figure 5] FIG. 5 is an explanatory diagram illustrating a third state of the switching device for the AC motor shown in FIG. [Figure 6] FIG. 6 is a graph showing the relationship between the rotation speed and torque in each state for the AC motor used in the in-vehicle system of FIG. [Figure 7] FIG. 7 is a circuit diagram that schematically illustrates an in-vehicle system including a switching device for an AC motor according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes exemplary embodiments of the present disclosure. Note that the following exemplary features [1] to [4] may be combined in any manner as long as they are not inconsistent.

[0010] [1] A switching device for switching the connection state of a winding of an AC motor having a plurality of phases, each phase having a first winding and a second winding, a switching unit for switching the connection state of the windings of the plurality of phases; The switching unit switches between a first state in which energization control for the first winding of each of the phase windings is permitted and energization control for the second winding of each of the phase windings is interrupted, a second state in which energization control for the second winding of each of the phase windings is permitted and energization control for the first winding of each of the phase windings is interrupted, and a third state in which energization control for the first winding and the second winding of each of the phase windings is permitted. AC motor switching device.

[0011] In the switching device of [1] above, the first state is an operating pattern in which each first winding of the windings of each phase is selectively used and each second winding is selectively not used, and the second state is an operating pattern in which each second winding of the windings of each phase is selectively used and each first winding is selectively not used, so this switching device can generate an operating pattern in which the first winding is used while suppressing the influence of the second winding, and an operating pattern in which the second winding is used while suppressing the influence of the first winding. Furthermore, this switching device can also generate an operating pattern in which both each first winding and each second winding are used, so the number of operating patterns of the AC motor can be further increased.

[0012] [2] A control unit that controls the switching unit, the multiple phase windings include a first phase winding, a second phase winding, and a third phase winding; the switching unit includes a first switching unit that switches between a first short-circuit state and a first release state, a second switching unit that switches between a second short-circuit state and a second release state, and a third switching unit that switches between a third short-circuit state and a third release state; the first short-circuit state is a state in which a first end portion, which is one end of the first winding of the first phase winding, is short-circuited to a first conductive path, a second end portion, which is one end of the first winding of the second phase winding, is short-circuited to a second conductive path, and a third end portion, which is one end of the first winding of the third phase winding, is short-circuited to a third conductive path, the first released state is a state in which the short circuit between the first end and the first conductive path is released, the short circuit between the second end and the second conductive path is released, and the short circuit between the third end and the third conductive path is released, the second short-circuit state is a state in which a fourth end portion, which is one end of the second winding of the first phase winding, and the first conductive path are short-circuited, a fifth end portion, which is one end of the second winding of the second phase winding, and the second conductive path are short-circuited, and a sixth end portion, which is one end of the second winding of the third phase winding, and the third conductive path are short-circuited, the second release state is a state in which the short circuit between the fourth end and the first conductive path is released, the short circuit between the fifth end and the second conductive path is released, and the short circuit between the sixth end and the third conductive path is released, the third short-circuit state is a state in which an other-end group including the other end of the first winding of the first-phase winding, the other end of the first winding of the second-phase winding, and the other end of the first winding of the third-phase winding is short-circuited to each other, the third release state is a state in which the other end group is released from short-circuiting with each other, the control unit sets the switching unit to the first state by setting the first switching unit to the first short-circuit state, the second switching unit to the second release state, and the third switching unit to the third short-circuit state; sets the switching unit to the second state by setting the first switching unit to the first release state, the second switching unit to the second short-circuit state, and the third switching unit to the third release state; and sets the switching unit to the third state by setting the first switching unit to the first short-circuit state, the second switching unit to the second release state, and the third switching unit to the third release state. A switching device for an AC motor according to [1].

[0013] The switching device of [2] above is intended for a three-phase AC motor and can be switched between at least three states (first state, second state, third state) by the simple method of changing the combination of short-circuit and release states of each switching section.

[0014] [3] The first winding of the first phase winding has a larger number of turns than the second winding of the first phase winding, the first winding of the second phase winding has a larger number of turns than the second winding of the second phase winding; The first winding of the third phase winding has a larger number of turns than the second winding of the third phase winding. [2] A switching device for an AC motor according to [2].

[0015] The switching device of [3] above can selectively use the first windings with a relatively large number of turns in the first state, thereby increasing impedance and facilitating the generation of larger torque. On the other hand, in the second state, it can selectively use the second windings with a relatively small number of turns, thereby reducing impedance and improving suitability for high-speed operation. In the third state, it can use not only the first windings with a relatively large number of turns but also the second windings, thereby further increasing torque.

[0016] [4] The control unit sets the switching unit to the third state when a rotation speed of the switching device of the AC motor and a vehicle equipped with the AC motor is within a first rotation speed range, sets the switching unit to the first state when the rotation speed of the vehicle is within a second rotation speed range that is a range of rotation speeds higher than the first rotation speed range, and sets the switching unit to the third state when the rotation speed of the vehicle is within a third rotation speed range that is a range of rotation speeds higher than the second rotation speed range. 2 state The switching device for an AC motor according to [3].

[0017] The switching device of [4] above can switch to the first state, which is suitable for high-speed driving, when the vehicle speed is within a relatively high third rotation speed range, and can switch to the third state, which is suitable for increasing torque, when the vehicle speed is within a relatively low first rotation speed range.Furthermore, this switching device can switch to the second state, which is suitable for balancing torque and high-speed driving, when the vehicle speed is within a medium second rotation speed range.

[0018] First Embodiment 1. Overview of the in-vehicle system 1 is a system applied to an AC motor 4 mounted on a vehicle, and is an electric motor system that can drive and control the AC motor 4. The in-vehicle system 1 includes the AC motor 4 and an electric motor drive device 2.

[0019] The AC motor 4 is a three-phase AC motor. The AC motor 4 is, for example, a three-phase drive motor that generates a driving force for rotating wheels provided on a vehicle in which the in-vehicle system 1 is installed. The AC motor 4 has built-in multi-phase (specifically, three-phase) windings 71, 72, and 73. The multi-phase windings 71, 72, and 73 function as stator windings provided on a stator. The winding 71 is also referred to as a U-phase winding 71. The winding 72 is also referred to as a V-phase winding 72. The winding 73 is also referred to as a W-phase winding 73. The U-phase corresponds to an example of a first phase. The V-phase corresponds to an example of a second phase. The W-phase corresponds to an example of a third phase. The AC motor 4 is a so-called Y-connected three-phase motor. The U-phase (first phase) winding 71, the V-phase (second phase) winding 72, and the W-phase (third phase) winding 73 can be connected at either the third switching section 23, which can be a neutral point, or the short-circuit section 90, which can be a neutral point.

[0020] The AC motor 4 includes multiple phase windings 71, 72, and 73, each of which has a first winding and a second winding, with the first winding and the second winding connected in series. The U-phase (first phase) winding 71 includes a first winding 71A and a second winding 71B, with the first winding 71A and the second winding 71B connected in series. The V-phase (second phase) winding 72 includes a first winding 72A and a second winding 72B, with the first winding 72A and the second winding 72B connected in series. The W-phase (third phase) winding 73 includes a first winding 73A and a second winding 73B, with the first winding 73A and the second winding 73B connected in series.

[0021] End 81A corresponds to an example of a first end. End 81A is one end of first winding 71A. End 81A is electrically connected to conductive path 61B of U-phase conductive path 61 and is short-circuited to conductive path 61B. End 82A corresponds to an example of a second end. End 82A is one end of first winding 72A. End 82A is electrically connected to conductive path 62B of V-phase conductive path 62 and is short-circuited to conductive path 62B. End 83A is an example of a third end. End 83A is one end of first winding 73A. End 83A is electrically connected to conductive path 63B of W-phase conductive path 63 and is short-circuited to conductive path 63B.

[0022] End 81B is the other end of the first winding 71A. End 81B is electrically connected to end 81C, which is one end of the second winding 71B, and is short-circuited to end 81C. End 82B is the other end of the first winding 72A. End 82B is electrically connected to end 82C, which is one end of the second winding 72B, and is short-circuited to end 82C. End 83B is the other end of the first winding 73A. End 83B is electrically connected to end 83C, which is one end of the second winding 73B, and is short-circuited to end 83C. End 81D is the other end of the second winding 71B. End 82D is the other end of the second winding 72B. End 83D is the other end of the second winding 73B. Ends 81D, 82D, and 83D are electrically connected to short-circuiting portion 90 and are short-circuited to each other via short-circuiting portion 90.

[0023] The pair of power paths 81, 82 are conductive paths through which DC power based on power from a battery (e.g., a high-voltage battery) not shown is transmitted. The power path 81 is a high-potential side power path. The power path 82 is a low-potential side power path. For example, a constant DC voltage can be applied between the pair of power paths 81, 82.

[0024] 2. Overview of electric motor drive unit The motor drive device 2 is a device that drives the AC motor 4 based on power supplied from a pair of power paths 81, 82. The motor drive device 2 is also a device that controls the operation of the AC motor 4. The motor drive device 2 has an inverter 6, three conduction paths (a U-phase conduction path 61, a V-phase conduction path 62, and a W-phase conduction path 63), and a switching device 10.

[0025] The inverter 6 is an inverter circuit that outputs three-phase AC power of U-phase, V-phase, and W-phase. The three-phase AC power output from the inverter 6 is supplied to the AC motor 4 via three conduction paths (a U-phase conduction path 61, a V-phase conduction path 62, and a W-phase conduction path 63) and is used to drive the rotation of the AC motor 4. The inverter 6 includes switching elements 6A, 6C, and 6E that function as upper arm elements and switching elements 6B, 6D, and 6F that function as lower arm elements. Each of the switching elements 6A, 6B, 6C, 6D, 6E, and 6F is configured, for example, by an insulated gate bipolar transistor (IGBT) and a freewheeling diode.

[0026] In the inverter 6, for example, switching elements 6A, 6B, 6C, 6D, 6E, and 6F receive an on-off signal (e.g., a PWM (pulse width modulation) signal) to repeatedly turn on and off, thereby generating three-phase AC power. The on-off control of the switching elements 6A, 6B, 6C, 6D, 6E, and 6F is performed, for example, by an electronic control device (e.g., an on-board ECU (Electronic Control Unit)) not shown. The method by which the electronic control device controls the inverter 6 is, for example, a three-phase modulation method using a PWM signal. Note that the method by which the electronic control device controls the inverter 6 may be any method capable of driving the AC motor 4, and various methods may be adopted, for example, known V / f control or known vector control.

[0027] In inverter 6, the U-phase switch pair is composed of switching element 6A, which is an upper arm element, and switching element 6B, which is a lower arm element. The V-phase switch pair is composed of switching element 6C, which is an upper arm element, and switching element 6D, which is a lower arm element. The W-phase switch pair is composed of switching element 6E, which is an upper arm element, and switching element 6F, which is a lower arm element.

[0028] The U-phase conductive path 61 is a conductive path between the switching elements 6A, 6B and the U-phase winding 71. The U-phase conductive path 61 includes conductive paths 61A and 61B. The conductive path 61A is an example of a first conductive path. The conductive path 61A is a conductive path between the switching elements 6A, 6B and the switch 21A. One end of the conductive path 61A is electrically connected to the conductive path between the switching elements 6A, 6B. The other end of the conductive path 61A is electrically connected to one end of the switch 21A. The conductive path 61B is electrically connected to the other end of the switch 21A and one end of the U-phase winding 71. When the switch 21A is in the on state, a short circuit can occur between the switching elements 6A, 6B and the U-phase winding 71, establishing electrical continuity.

[0029] The V-phase conductive path 62 is a conductive path between the switching elements 6C, 6D and the V-phase winding 72. The V-phase conductive path 62 includes conductive paths 62A and 62B. The conductive path 62A corresponds to an example of a second conductive path. The conductive path 62A is a conductive path between the switching elements 6C, 6D and the switch 21B. One end of the conductive path 62A is electrically connected to the conductive path between the switching elements 6C, 6D. The other end of the conductive path 62A is electrically connected to one end of the switch 21B. The conductive path 62B is electrically connected to the other end of the switch 21B and one end of the V-phase winding 72. When the switch 21B is in the on state, a short circuit can occur between the switching elements 6C, 6D and the V-phase winding 72, establishing electrical continuity.

[0030] The W-phase conductive path 63 is a conductive path between the switching elements 6E, 6F and the W-phase winding 73. The W-phase conductive path 63 includes conductive paths 63A and 63B. The conductive path 63A is an example of a third conductive path. The conductive path 63A is a conductive path between the switching elements 6E, 6F and the switch 21C. One end of the conductive path 63A is electrically connected to the conductive path between the switching elements 6E, 6F. The other end of the conductive path 63A is electrically connected to one end of the switch 21C. The conductive path 63B is electrically connected to the other end of the switch 21C and one end of the W-phase winding 73. When the switch 21C is in the on state, a short circuit can occur between the switching elements 6E, 6F and the W-phase winding 73, establishing electrical continuity.

[0031] 3. Switching device configuration The switching device 10 is a device that switches the state of the windings of the AC motor 4. The switching device 10 includes a switching unit 20 and a control unit 30.

[0032] The control unit 30 is a device that controls the switching unit 20. The control unit 30 may be, for example, an electronic control unit such as an in-vehicle ECU, or an information processing device having an MPU (Micro-Processing Unit) or the like. The control unit 30 controls the on / off of each switch that constitutes the switching unit 20. Specifically, the control unit 30 can output an on signal and an off signal to each of the switches 21A, 21B, 21C, 22A, 22B, 22C, 23A, 23B, and 23C.

[0033] The switching unit 20 is a device that switches the connection state of the multi-phase windings 71, 72, and 73. The switching unit 20 has a first switching unit 21, a second switching unit 22, and a third switching unit 23. The first switching unit 21 switches between a first short-circuit state and a first release state. The second switching unit 22 switches between a second short-circuit state and a second release state. The third switching unit 23 switches between a third short-circuit state and a third release state.

[0034] The first switching unit 21 includes switches 21A, 21B, and 21C. Each of the switches 21A, 21B, and 21C may be configured with one or more semiconductor switch elements (for example, FETs (Field Effect Transistors) or IGBTs), or may be configured with one or more mechanical relays.

[0035] The first short-circuit state is a state in which switches 21A, 21B, and 21C are all turned on. When switch 21A is in the on state, current can flow in both directions through switch 21A. When switch 21B is in the on state, current can flow in both directions through switch 21B. When switch 21C is in the on state, current can flow in both directions through switch 21C. In other words, the first short-circuit state is a state in which end 81A, which is one end of U-phase first winding 71A, is short-circuited with conductive path 61A (first conductive path), end 82A, which is one end of V-phase first winding 72A, is short-circuited with conductive path 62A (second conductive path), and end 83A, which is one end of W-phase first winding 73A, is short-circuited with conductive path 63A (third conductive path).

[0036] The first release state is a state in which switches 21A, 21B, and 21C are all turned off. When switch 21A is in the off state, bidirectional current is cut off in switch 21A. When switch 21B is in the off state, bidirectional current is cut off in switch 21B. When switch 21C is in the off state, bidirectional current is cut off in switch 21C. In other words, the first release state is a state in which the short circuit between end 81A (first end) and conductive path 61A (first conductive path) is released, the short circuit between end 82A (second end) and conductive path 62A (second conductive path) is released, and the short circuit between end 83A (third end) and conductive path 63A (third conductive path) is released. In the first release state, no current flows between conductive path 61A and conductive path 61B, no current flows between conductive path 62A and conductive path 62B, and no current flows between conductive path 63A and conductive path 63B. In the first release state, no current is supplied to drive the first windings 71A, 72A, and 73A.

[0037] The second switching unit 22 includes switches 22A, 22B, and 22C. Each of the switches 22A, 22B, and 22C may be configured with one or more semiconductor switch elements (for example, FETs or IGBTs) or one or more mechanical relays.

[0038] The second short-circuit state is a state in which switches 22A, 22B, and 22C are all turned on. When switch 22A is in the on state, current can flow in both directions through switch 22A. When switch 22B is in the on state, current can flow in both directions through switch 22B. When switch 22C is in the on state, current can flow in both directions through switch 22C. In other words, the second short-circuit state is a state in which end 81C (fourth end) and conductive path 61A (first conductive path) are short-circuited, end 82C (fifth end) and conductive path 62A (second conductive path) are short-circuited, and end 83C (sixth end) and conductive path 63A (third conductive path) are short-circuited.

[0039] The second release state is a state in which switches 22A, 22B, and 22C are all turned off. When switch 22A is in the off state, bidirectional current is cut off in switch 22A. When switch 22B is in the off state, bidirectional current is cut off in switch 22B. When switch 22C is in the off state, bidirectional current is cut off in switch 22C. In other words, the second release state is a state in which the short circuit between end 81C (fourth end) and conductive path 61A (first conductive path) is released, the short circuit between end 82C (fifth end) and conductive path 62A (second conductive path) is released, and the short circuit between end 83C (sixth end) and conductive path 63A (third conductive path) is released.

[0040] The third short-circuit state is a state in which switches 23A, 23B, and 23C are all turned on. When switches 23A, 23B, and 23C are all turned on, the other ends of first windings 71A, 72A, and 73A are short-circuited to each other. When switch 23A is turned on, current can flow in both directions through switch 23A. When switch 23B is turned on, current can flow in both directions through switch 23B. When switch 23C is turned on, current can flow in both directions through switch 23C. The third short-circuit state is a state in which end 81B, which is the other end of U-phase first winding 71A, end 82B, which is the other end of V-phase first winding 72A, and end 83B, which is the other end of W-phase first winding 73A, are short-circuited to each other and have the same potential. The multiple end portions constituted by end portions 81B, 82B, and 83B are the other end group, and the third short-circuit state is a state in which this other end group is short-circuited to each other and has the same potential.

[0041] The third release state is a state in which switches 23A, 23B, and 23C are all turned off. When switch 23A is in the off state, bidirectional current is cut off at switch 23A. When switch 23B is in the off state, bidirectional current is cut off at switch 23B. When switch 23C is in the off state, bidirectional current is cut off at switch 23C. The third release state is a state in which the short circuits between the other end groups are released, and specifically, a state in which no current flows between end 81B and end 82B, between end 82B and end 83B, or between end 81B and end 83B via switches 23A, 23B, and 23C.

[0042] 4. Switching device operation In a representative example of this embodiment described below, the first winding 71A of the U-phase (first phase) winding 71 has a larger number of turns than the second winding 71B. The first winding 72A of the V-phase (second phase) winding 72 has a larger number of turns than the second winding 72B. The first winding 73A of the W-phase (third phase) winding 73 has a larger number of turns than the second winding 73B. That is, in each phase, the number of turns of the first winding is larger than the number of turns of the second winding.

[0043] The switching unit 20 switches between a first state, a second state, a third state, and a fourth state. The control unit 30 controls the switching unit 20 to switch between the first state, the second state, the third state, and the fourth state.

[0044] As shown in FIG. 2, the first state is a state in which the first switching unit 21 is in a short-circuited state (first short-circuited state), the second switching unit 22 is in a released state (second released state), and the third switching unit 23 is in a short-circuited state (third short-circuited state). In the first state, the windings to which current is applied are the first windings 71A, 72A, and 73A. That is, in the first state, among the multi-phase windings 71, 72, and 73, current application control is permitted for the first windings 71A, 72A, and 73A, and current application control for the second windings 71B, 72B, and 73B is blocked. As shown in FIG. 3, in the first state, each of the switches 21A, 21B, and 21C is in an ON state, each of the switches 22A, 22B, and 22C is in an OFF state, and each of the switches 23A, 23B, and 23C is in an ON state, and the third switching unit 23 is at the neutral point. Therefore, a driving current flows through each of the first windings 71A, 72A, and 73A, but no driving current flows through each of the second windings 71B, 72B, and 73B.

[0045] As shown in FIG. 2, the second state is a state in which the first switching unit 21 is in the released state (first released state), the second switching unit 22 is in the short-circuited state (second short-circuited state), and the third switching unit 23 is in the released state (third released state). In the second state, the windings to which current is applied are the second windings 71B, 72B, and 73B. That is, the second state is a state in which, among the multi-phase windings 71, 72, and 73, current application control is permitted for the second windings 71B, 72B, and 73B, and current application control for the first windings 71A, 72A, and 73A is cut off. As shown in FIG. 4, in the second state, each of the switches 22A, 22B, and 22C is in the ON state, each of the switches 21A, 21B, and 21C is in the OFF state, and each of the switches 23A, 23B, and 23C is in the OFF state, and the short-circuit unit 90 serves as the neutral point. Therefore, a driving current flows through each of the second windings 71B, 72B, and 73B, but no driving current flows through each of the first windings 71A, 72A, and 73A.

[0046] As shown in FIG. 2, the third state is a state in which the first switching unit 21 is in a short-circuited state (first short-circuited state), the second switching unit 22 is in a released state (second released state), and the third switching unit 23 is in a released state (third released state). In the third state, the windings to which current is applied are the first windings 71A, 72A, and 73A and the second windings 71B, 72B, and 73B. That is, the third state is a state in which current application control is permitted to all of the first windings 71A, 72A, and 73A and the second windings 71B, 72B, and 73B in the multi-phase windings 71, 72, and 73. As shown in FIG. 5, in the third state, each of the switches 21A, 21B, and 21C is in an ON state, each of the switches 22A, 22B, and 22C is in an OFF state, and each of the switches 23A, 23B, and 23C is in an OFF state, and the short-circuit unit 90 serves as the neutral point. Therefore, the first winding 71A and the second winding 71B connected in series function as a U-phase winding as a whole, and a driving current flows through them as a whole; the first winding 72A and the second winding 72B connected in series function as a V-phase winding as a whole, and a driving current flows through them as a whole; and the first winding 73A and the second winding 73B connected in series function as a W-phase winding as a whole, and a driving current flows through them as a whole.

[0047] 2, the fourth state is a state in which the first switching unit 21 is in the released state (first release state), the second switching unit 22 is in the released state (second release state), and the third switching unit 23 is in the released state (third release state). In the fourth state, no driving current flows through the first windings 71A, 72A, 73A and the second windings 71B, 72B, 73B.

[0048] The control unit 30 controls the switching unit 20 to switch to one of the above states. When a first condition is met, the control unit 30 sets the first switching unit 21 to the first short-circuit state, the second switching unit 22 to the second release state, and the third switching unit 23 to the third short-circuit state, thereby setting the switching unit 20 to the first state. In this case, the in-vehicle system 1 can be used to selectively supply power only to the first winding having a relatively large number of turns in each phase. On the other hand, when a second condition different from the first condition is met, the control unit 30 sets the first switching unit 21 to the first release state, the second switching unit 22 to the second short-circuit state, and the third switching unit 23 to the third release state, thereby setting the switching unit 20 to the second state. In this case, the in-vehicle system 1 can be used to selectively supply power only to the second winding having a relatively small number of turns in each phase. Furthermore, when a third condition different from the first and second conditions is met, the control unit 30 sets the first switching unit 21 to the first short-circuit state, the second switching unit 22 to the second release state, and the third switching unit 23 to the third release state, thereby setting the switching unit 20 to the third state. In this case, the in-vehicle system 1 can supply power to both the first winding and the second winding in each phase. When a fourth condition different from the first, second, and third conditions is met, the control unit 30 sets the first switching unit 21 to the first release state, the second switching unit 22 to the second release state, and the third switching unit 23 to the third release state, thereby setting the switching unit 20 to the fourth state. In this case, the in-vehicle system 1 can stop the power supply to the first winding and the second winding in each phase. The first condition, second condition, third condition, and fourth condition may be different from each other.

[0049] 5.Example of effects In the switching device 10, the first state is an operating pattern in which the first windings 71A, 72A, and 73A of the multiple phase windings 71, 72, and 73 are selectively used, and the second windings 71B, 72B, and 73B are selectively not used. The second state is an operating pattern in which the second windings 71B, 72B, and 73B of the multiple phase windings are selectively used, and the first windings 71A, 72A, and 73A are selectively not used. Because the switching device 10 switches between states in this manner, it is possible to generate an operating pattern in which the first windings 71A, 72A, and 73A are used while suppressing the influence of the second windings 71B, 72B, and 73B, and an operating pattern in which the second windings 71B, 72B, and 73B are used while suppressing the influence of the first windings 71A, 72A, and 73A. Furthermore, by switching to the third state, the switching device 10 can also generate an operating pattern that uses both the first winding and the second winding in each phase, thereby further increasing the number of operating patterns of the AC motor 4.

[0050] The switching device 10 can be switched between at least three states (first state, second state, third state) by a simple method of changing the combination of the short-circuited state and the released state of the first switching unit 21, the second switching unit 22, and the third switching unit 23.

[0051] In the first state, the switching device 10 can selectively use the first windings 71A, 72A, and 73A, which have a relatively large number of turns, thereby increasing impedance and facilitating the generation of larger torque. Meanwhile, in the second state, the switching device 10 can selectively use the second windings 71B, 72B, and 73B, which have a relatively small number of turns, thereby reducing impedance and facilitating the generation of larger torque. In the third state, the switching device 10 can use the second windings 71B, 72B, and 73B in addition to the first windings 71A, 72A, and 73A, which have a relatively large number of turns, thereby facilitating the generation of even larger torque.

[0052] In this specification, the first condition may be "the rotation speed of the vehicle equipped with the in-vehicle system 1 is within a second rotation speed range." The second condition may be "the rotation speed of the vehicle equipped with the in-vehicle system 1 is within a third rotation speed range." Furthermore, the third condition may be "the rotation speed of the vehicle equipped with the in-vehicle system 1 is within a first rotation speed range." In this case, the first rotation speed range corresponding to the third condition may be a range in which the rotation speed of the vehicle is less than X1, the second rotation speed range corresponding to the first condition may be a range in which the rotation speed of the vehicle is equal to or greater than X1 and less than X2, and the third rotation speed range corresponding to the second condition may be a range in which the rotation speed of the vehicle is equal to or greater than X2. In this example, the second rotation speed range is a range in which the rotation speed is higher than the first rotation speed range, and the third rotation speed range is a range in which the rotation speed is higher than the second rotation speed range.

[0053] The relationship between the rotation speed and torque of the AC motor 4 in each of the first, second, and third states is shown in FIG. 6, for example. In the example of FIG. 6, in a first rotation speed range where the rotation speed of the vehicle equipped with the in-vehicle system 1 is less than X1, the torque is greatest in the third state. Furthermore, in a second rotation speed range where the rotation speed of the vehicle is equal to or greater than X1 but less than X2, the torque is greatest in the first state. Furthermore, in a third rotation speed range where the rotation speed of the vehicle is equal to or greater than X2, the torque is greatest in the second state. In this example, if the control unit 30 controls the switching unit 20 to switch to the third state when the rotation speed of the vehicle is within the first rotation speed range, which is relatively low, this is advantageous in situations where high torque is required at low rotation speeds, such as when starting or climbing a slope. Furthermore, if the control unit 30 controls the switching unit 20 to switch to the second state when the rotation speed of the vehicle is within the third rotation speed range, which is relatively high, this is advantageous in situations where high speeds are maintained but acceleration and deceleration are infrequent, such as when driving on a highway. Furthermore, if the control unit 30 operates to switch the switching unit 20 to the first state when the vehicle's rotation speed is within the medium second rotation speed range, this is advantageous in situations where acceleration / deceleration or course changes occur at medium speeds, such as when driving in urban areas.

[0054] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiment may be modified as follows.

[0055] In the above-described embodiment, the switching device 10 has the control unit 30, but the switching device may not have the control unit 30. For example, the switching device may be configured to be composed only of the above-described switching unit 20, and this switching device (specifically, the switching unit 20) may be configured to perform switching operation upon receiving an instruction from an external device (for example, a device having the same function as the above-described control unit 30).

[0056] In the above-described embodiment, each phase winding is divided into two, but each phase winding may be divided into three or more. Fig. 7 shows an in-vehicle system 101 in which an electric motor drive device 202 is used instead of the electric motor drive device 2 of Fig. 1. In the electric motor drive device 202 of Fig. 7, an AC motor 104 is used instead of the AC motor 4 of Fig. 1. The AC motor 104 differs from the AC motor 4 of Fig. 1 in that, instead of the configuration in which the other end of each of the second windings 71B, 72B, and 73B is short-circuited to the short-circuit portion 90 as in Fig. 1, third windings 71C, 72C, and 73C are provided between the other end of each of the second windings 71B, 72B, and 73B and the short-circuit portion 190, respectively. The other configuration is the same as that of the AC motor 4 of Fig. 1. Like U-phase winding 171, V-phase winding 172, and W-phase winding 173 in AC motor 104 of Fig. 7, third windings 71C, 72C, and 73C may be provided between second windings 71B, 72B, and 73B, respectively, and short-circuit portion 190. In this example, as shown in Fig. 7, it is only necessary to provide a fourth switching unit 122 that switches switches 122A, 122B, and 122C between an on state and an off state, and a fifth switching unit 123 that switches switches 123A, 123B, and 123C between an on state and an off state. In the example of FIG. 7, to attain the first state described above, in addition to the control of the first state in the first embodiment, it is sufficient to turn off all of the switches 122A, 122B, 122C, 123A, 123B, and 123C; to attain the second state, in addition to the control of the second state in the first embodiment, it is sufficient to turn off all of the switches 122A, 122B, and 122C and turn on all of the switches 123A, 123B, and 123C; to attain the third state, in addition to the control of the third state in the first embodiment, it is sufficient to turn off all of the switches 122A, 122B, and 122C and turn on all of the switches 123A, 123B, and 123C; and to attain the fourth state, in addition to the control of the fourth state in the first embodiment, it is sufficient to turn off all of the switches 122A, 122B, 122C, 123A, 123B, and 123C.Furthermore, by turning off all of the switching units 21, 22, 23, and 123 and turning on the switching unit 122, a fourth state is possible in which the third windings 71C, 72C, and 73C are selectively used without using the first and second windings. By turning off all of the switching units 22, 23, 122, and 123 and turning on the switching unit 21, a fifth state is possible in which the first, second, and third windings are all used. Furthermore, other states can also be realized. In this electric motor drive device 2, in a configuration in which each phase winding is divided into three or more windings, it is possible to select only one type of winding for each phase (in the configuration of FIG. 7, one type of the first, second, or third winding), or to select only two types, or to select all types.

[0057] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0058] 1,101: In-vehicle systems 4,104: AC motor 10: Switching device (AC motor switching device) 20: Switching section 21: First switching section 22: Second switching section 23: Third switching section 30: Control unit 61: First conductive path 62: Second conductive path 63: Third conductive path 71: U phase winding 72: V-phase winding 73: W-phase winding 71A, 72A, 73A: 1st winding 71B, 72B, 73B: Second winding 81A: First end 81B: other end 81C: 4th end 82A:Second end 82B: other end 82C: 5th end 83A: Third end 83B: other end 83C: 6th end

Claims

1. 1. A switching device for switching connection states of windings of an AC motor having a plurality of phases, each phase having a first winding and a second winding, comprising: a switching unit for switching the connection state of the windings of the plurality of phases; the switching unit switches between a first state in which energization control for the first winding of each of the phase windings is permitted and energization control for the second winding of each of the phase windings is interrupted, a second state in which energization control for the second winding of each of the phase windings is permitted and energization control for the first winding of each of the phase windings is interrupted, and a third state in which energization control for the first winding and the second winding of each of the phase windings is permitted, a control unit that controls the switching unit, the multiple phase windings include a first phase winding, a second phase winding, and a third phase winding; the switching unit includes a first switching unit that switches between a first short-circuit state and a first release state, a second switching unit that switches between a second short-circuit state and a second release state, and a third switching unit that switches between a third short-circuit state and a third release state; the first short-circuit state is a state in which a first end portion, which is one end of the first winding of the first phase winding, is short-circuited to a first conductive path, a second end portion, which is one end of the first winding of the second phase winding, is short-circuited to a second conductive path, and a third end portion, which is one end of the first winding of the third phase winding, is short-circuited to a third conductive path, the first released state is a state in which the short circuit between the first end and the first conductive path is released, the short circuit between the second end and the second conductive path is released, and the short circuit between the third end and the third conductive path is released, the second short-circuit state is a state in which a fourth end portion, which is one end of the second winding of the first phase winding, is short-circuited with the first conductive path, a fifth end portion, which is one end of the second winding of the second phase winding, is short-circuited with the second conductive path, and a sixth end portion, which is one end of the second winding of the third phase winding, is short-circuited with the third conductive path, the second released state is a state in which the short circuit between the fourth end and the first conductive path is released, the short circuit between the fifth end and the second conductive path is released, and the short circuit between the sixth end and the third conductive path is released, the third short-circuit state is a state in which an other-end group including the other end of the first winding of the first-phase winding, the other end of the first winding of the second-phase winding, and the other end of the first winding of the third-phase winding is short-circuited to each other, the third release state is a state in which the other end group is released from short-circuiting with each other, the control unit sets the switching unit to the first state by setting the first switching unit to the first short-circuit state, the second switching unit to the second release state, and the third switching unit to the third short-circuit state; sets the switching unit to the second state by setting the first switching unit to the first release state, the second switching unit to the second short-circuit state, and the third switching unit to the third release state; and sets the switching unit to the third state by setting the first switching unit to the first short-circuit state, the second switching unit to the second release state, and the third switching unit to the third release state. AC motor switching device.

2. The first winding of the first phase winding has a larger number of turns than the second winding of the first phase winding, the first winding of the second phase winding has a larger number of turns than the second winding of the second phase winding; the first winding of the third phase winding has a larger number of turns than the second winding of the third phase winding; The control unit sets the switching unit to the third state when a rotation speed of the switching device for the AC motor and a vehicle equipped with the AC motor is within a first rotation speed range, sets the switching unit to the first state when the rotation speed of the vehicle is within a second rotation speed range that is a range of rotation speeds higher than the first rotation speed range, and sets the switching unit to the second state when the rotation speed of the vehicle is within a third rotation speed range that is a range of rotation speeds higher than the second rotation speed range.

2. The switching device for an AC motor according to claim 1.

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