Tap changer

Abstract

This tap changer (50) comprises: a switching unit (60U) that switches the connection state of a plurality of winding units (31U, 32U) between a first state and a second state; and a control unit (70) that controls the switching unit (60U). The switching unit (60U) has a first switch (61U) and second switches (62U, 63U). The connection state is set to a first state when the first switch (61U) is in an ON state and the second switches (62U, 63U) are in an OFF state, and the connection state is set to a second state when the first switch (61U) is in the OFF state and the second switches (62U, 63U) are in the ON state. The control unit (70) switches the switching unit (60U) between the first state and the second state after an ON period in which the first switch (61U) and the second switches (62U, 63U) are controlled to be in the ON state.

Description

Winding switching device

[0001] The present disclosure relates to a winding switching device.

[0002] Patent Document 1 discloses a winding switching device. This winding switching device includes a switching unit that switches the connection state of a plurality of coil units. The switching unit has a first relay switch and a second relay switch. The second relay switch is connected in series to the first coil unit and the second coil unit. The first relay switch is connected in parallel to the second coil unit and the first relay switch. When the first relay switch is in the on state and the second relay switch is in the off state, current flows only through the first coil unit. When the first relay switch is in the off state and the second relay switch is in the on state, current flows through the first coil unit and the second coil unit.

[0003] Japanese Unexamined Patent Application Publication No. 2024-85142

[0004] In the configuration of Patent Document 1, when switching the connection state, there is a possibility that both the first relay switch and the second relay switch may temporarily enter the off state due to variations in the performance of each device, variations in control timing, etc. In this case, a large surge voltage may be applied to the first relay switch and the second relay switch. Therefore, there is room for improvement in this regard.

[0005] An object of the present disclosure is to provide a technique capable of suppressing the application of a surge voltage to the switches constituting the switching unit.

[0006] The winding switching device of the present disclosure is a winding switching device used in a motor including a plurality of winding sections, comprising: a switching section that switches the connection state of the plurality of winding sections between a first state and a second state; and a control section that controls the switching section, wherein the switching section has a first switch and a second switch, the connection state becomes the first state when the first switch is ON and the second switch is OFF, and the connection state becomes the second state when the first switch is OFF and the second switch is ON, the first switch and the second switch are positioned to form a closed circuit including the winding section, the first switch and the second switch when they are each ON, and the control section switches the switching section between the first state and the second state with an ON period in between for controlling the first switch and the second switch to be ON.

[0007] According to the technology disclosed herein, it is possible to suppress the application of surge voltage to the switches constituting the switching unit.

[0008] Figure 1 is a schematic diagram showing an in-vehicle system equipped with a winding switching device according to the first embodiment. Figure 2 is a schematic diagram of the winding switching device according to the first embodiment. Figure 3 is a timing chart showing the operation of the signal output circuit, first delay circuit, second delay circuit, first switch, and second switch when the connection state of the winding section switches from the first state to the second state. Figure 4 is an explanatory diagram showing the operation of the winding switching device when it is in the first state. Figure 5 is an explanatory diagram showing the operation of the winding switching device during the ON period. Figure 6 is an explanatory diagram showing the operation of the winding switching device when it has switched to the second state. Figure 7 is a timing chart showing the operation of the signal output circuit, first delay circuit, second delay circuit, first switch, and second switch when the connection state of the winding section switches from the second state to the first state. Figure 8 is a schematic diagram of the winding switching device according to the second embodiment. Figure 9 is a schematic diagram of the winding switching device according to the third embodiment. Figure 10 is a schematic diagram showing an in-vehicle system equipped with a winding switching device according to the fourth embodiment.

[0009] [Description of Embodiments of the Disclosure] First, embodiments of the Disclosure will be listed and described.

[0010] [1] A winding switching device used in a motor including a plurality of winding sections, comprising: a switching section that switches the connection state of the plurality of winding sections between a first state and a second state; and a control section that controls the switching section, wherein the switching section has a first switch and a second switch, the connection state becomes the first state when the first switch is ON and the second switch is OFF, and the connection state becomes the second state when the first switch is OFF and the second switch is ON, the first switch and the second switch are positioned to form a closed circuit including the winding section, the first switch and the second switch when they are each ON, and the control section switches the switching section between the first state and the second state with an ON period in between for controlling the first switch and the second switch to be ON.

[0011] The above-described winding switching device switches the switching section between a first state and a second state with an ON period in between, thus avoiding the generation of surge voltage due to the first and second switches being in the OFF state. In other words, the above-described winding switching device can suppress the application of surge voltage to the first and second switches that constitute the switching section.

[0012] [2] The winding switching device according to [1], wherein the ON period is set to a time during which the temperature of the closed circuit does not exceed the allowable temperature of the first switch, and the temperature of the closed circuit does not exceed the allowable temperature of the second switch.

[0013] When the first and second switches are switched to the ON state, a closed circuit including the winding section, the first and second switches is formed, and current flows back. Therefore, if the ON period is long, the first and second switches may overheat and fail. In this regard, the above-described winding switching device has an ON period set to a time during which the temperature of the closed circuit does not exceed the allowable temperature of the first switch, and also a time during which the temperature of the closed circuit does not exceed the allowable temperature of the second switch. Therefore, it is possible to prevent the first and second switches from failing due to overheating during the ON period.

[0014] [3] The control unit comprises a control circuit, a first delay circuit provided in correspondence with the first switch, and a second delay circuit provided in correspondence with the second switch, wherein the control circuit switches between a first control state in which it outputs an ON signal to the first switch and an OFF signal to the second switch, and a second control state in which it outputs an OFF signal to the first switch and an ON signal to the second switch, the first delay circuit delays only the OFF signal of the ON / OFF signal output from the control circuit to the first switch, and the second delay circuit delays only the OFF signal of the ON / OFF signal output from the control circuit to the second switch, the winding switching device according to [1] or [2].

[0015] When the control circuit switches from the first control state to the second control state, the second delay circuit immediately outputs the ON signal input from the control circuit, and the first delay circuit outputs the OFF signal input from the control circuit with a delay. Therefore, the first and second switches remain ON until the OFF signal is output from the first delay circuit. Conversely, when the control circuit switches from the second control state to the first control state, the first delay circuit immediately outputs the ON signal input from the control circuit, and the second delay circuit outputs the OFF signal input from the control circuit with a delay. Therefore, the first and second switches remain ON until the OFF signal is output from the second delay circuit. In this way, the above-described winding switching device makes it possible to create an ON period in which the first and second switches remain ON by utilizing the first and second delay circuits.

[0016] [4] The first delay circuit comprises a first resistor provided between the control circuit and the first switch, a first capacitor that together with the first resistor constitutes an RC circuit, and a first diode connected in parallel with the first resistor, wherein the anode of the first diode is electrically connected to the conductive path on the control circuit side, and the cathode of the first diode is electrically connected to the conductive path on the first switch side. The second delay circuit comprises a second resistor provided between the control circuit and the second switch, a second capacitor that together with the second resistor constitutes an RC circuit, and a second diode connected in parallel with the second resistor, wherein the anode of the second diode is electrically connected to the conductive path on the control circuit side, and the cathode of the second diode is electrically connected to the conductive path on the second switch side. The winding switching device as described in [3].

[0017] According to the above-described winding switching device, the first delay circuit and the second delay circuit can be simplified.

[0018] [5] The winding switching device according to [1], wherein the control unit, after starting control to turn on the first switch and the second switch, determines that the first switch and the second switch have turned on, terminates the on period and controls the connection state to the first state or the second state.

[0019] The winding switching device described above can switch the connection state to either the first state or the second state after confirming that the first switch and the second switch are in the ON state.

[0020] [6] The winding switching device according to [1], wherein the control unit, after starting control to turn on the first switch and the second switch, determines that the current flowing through the closed circuit exceeds a threshold current, terminates the on period and controls the connection state to the first state or the second state.

[0021] The above-described winding switching device can terminate the ON period before the current flowing through the closed circuit becomes too large, and switch the connection state to the first or second state.

[0022] [7] The winding switching device according to [6], wherein at least two second switches are provided, each second switch forms a separate closed circuit with the first switch, and the control unit, after starting control to turn on the first switch and the second switch, determines that the current flowing through the common path of the separate closed circuits exceeds a threshold current, terminates the on period and controls the connection state to the first state or the second state.

[0023] The above-described winding switching device can terminate the ON period before the current flowing in common between the two closed circuits becomes too large, and switch the connection state to either the first or second state.

[0024] [Details of Embodiments of the Disclosure] 1. First Embodiment 1-1. Configuration of the In-Vehicle System 1 The winding switching device 50 of the first embodiment shown in Figure 1 is used in a motor 30 provided in the in-vehicle system 1.

[0025] The in-vehicle system 1 includes a battery 10. A positive electrode conductive path 91 is electrically connected to the high-potential terminal of the battery 10. A negative electrode conductive path 92 is electrically connected to the low-potential terminal of the battery 10.

[0026] The in-vehicle system 1 includes an inverter 11. The inverter 11 generates three-phase AC power based on power from the battery 10. The three-phase AC power output from the inverter 11 is supplied to the motor 30 via three conductive paths (U-phase conductive path 21, V-phase conductive path 22, and W-phase conductive path 23) and used to rotate the motor 30. The inverter 11 includes switching elements 12, 14, and 16, which are high-potential side switching elements, and switching elements 13, 15, and 17, which are low-potential side switching elements. Switching elements 12 and 13 are connected in series between the positive electrode conductive path 91 and the negative electrode conductive path 92. Conductive path 21 is electrically connected to the conductive path between switching elements 12 and 13. Switching elements 14 and 15 are connected in series between the positive electrode conductive path 91 and the negative electrode conductive path 92. Conductive path 22 is electrically connected to the conductive path between switching elements 14 and 15. The switching elements 16 and 17 are connected in series between the positive electrode conductive path 91 and the negative electrode conductive path 92. A conductive path 23 is electrically connected to the conductive path between the switching elements 16 and 17.

[0027] The motor 30 provides rotational force to, for example, the wheels of a vehicle (not shown). In this embodiment, the motor 30 is a multiphase motor, specifically a three-phase motor. In this embodiment, the motor 30 is Y-connected. The motor 30 has U-phase windings 31U, 32U, V-phase windings 31V, 32V, and W-phase windings 31W, 32W.

[0028] 1-2. Configuration of the Winding Switching Device 50 The winding switching device 50 has switching sections 60U, 60V, and 60W, and a control unit 70. Switching section 60U corresponds to the U phase. Switching section 60U has a first switch 61U and second switches 62U and 63U. Switching section 60V corresponds to the V phase. Switching section 60V has a first switch 61V and second switches 62V and 63V. Switching section 60W corresponds to the W phase. Switching section 60W has a first switch 61W and second switches 62W and 63W.

[0029] One end of the winding section 31U and one end of the second switch 62U are electrically connected to the conductive path 21. One end of the first switch 61U and one end of the second switch 63U are electrically connected to the other end of the winding section 31U. The other end of the second switch 62U is electrically connected to the other end of the first switch 61U and one end of the winding section 32U. The other end of the second switch 63U and the other end of the winding section 32U are electrically connected to the neutral point 33.

[0030] The switching unit 60U sets the connection state of the winding sections 31U and 32U to a first state when the first switch 61U is ON and the second switches 62U and 63U are OFF. The first state is a series connection state in which the winding sections 31U and 32U are connected in series between the conductive path 21 and the neutral point 33. The switching unit 60U sets the connection state of the winding sections 31U and 32U to a second state when the first switch 61U is OFF and the second switches 62U and 63U are ON. The second state is a parallel connection state in which the winding sections 31U and 32U are connected in parallel between the conductive path 21 and the neutral point 33.

[0031] One end of the winding section 31V and one end of the second switch 62V are electrically connected to the conductive path 22. One end of the first switch 61V and one end of the second switch 63V are electrically connected to the other end of the winding section 31V. The other end of the second switch 62V is electrically connected to the other end of the first switch 61V and one end of the winding section 32V. The other end of the second switch 63V and the other end of the winding section 32V are electrically connected to the neutral point 33.

[0032] When the first switch 61V is ON and the second switches 62V and 63V are OFF, the switching unit 60V sets the connection state of the winding sections 31V and 32V to the first state. The first state is a series connection state in which the winding sections 31V and 32V are connected in series between the conductive path 22 and the neutral point 33. When the first switch 61V is OFF and the second switches 62V and 63V are ON, the switching unit 60V sets the connection state of the winding sections 31V and 32V to the second state. The second state is a parallel connection state in which the winding sections 31V and 32V are connected in parallel between the conductive path 22 and the neutral point 33.

[0033] One end of the winding section 31W and one end of the second switch 62W are electrically connected to the conductive circuit 23. One end of the first switch 61W and one end of the second switch 63W are electrically connected to the other end of the winding section 31W. The other end of the second switch 62W is electrically connected to the other end of the first switch 61W and one end of the winding section 32W. The other end of the second switch 63W and the other end of the winding section 32W are electrically connected to the neutral point 33.

[0034] When the first switch 61W is ON and the second switches 62W and 63W are OFF, the switching unit 60W sets the connection state of the winding sections 31W and 32W to a first state. In the first state, the winding sections 31W and 32W are connected in series between the conductive path 23 and the neutral point 33. When the first switch 61W is OFF and the second switches 62W and 63W are ON, the switching unit 60W sets the connection state of the winding sections 31W and 32W to a second state. In the second state, the winding sections 31W and 32W are connected in parallel between the conductive path 23 and the neutral point 33.

[0035] The control unit 70, for example, includes an MCU and controls the inverter 11. By controlling the inverter 11, the control unit 70 supplies three-phase AC power to the motor 30.

[0036] The control unit 70 switches the switching unit 60U between a first state and a second state. In this embodiment, the control unit 70 switches the switching unit 60U between a first state and a second state using zero-cross switch control. Zero-cross switch control is a control method that switches the switch at the timing when the AC current becomes 0A.

[0037] The control unit 70 switches the switching unit 60U between a first state and a second state, with an ON period in between during which the first switch 61U and the second switches 62U and 63U are controlled to the ON state. When the first switch 61U and the second switches 62U and 63U are ON, a first closed circuit including the winding unit 31U, the first switch 61U, and the second switch 62U, and a second closed circuit including the winding unit 32U, the first switch 61U, and the second switch 63U are formed. The ON period is set to a time during which the temperature of these closed circuits does not exceed the allowable temperature of the first switch 61U, and also a time during which the temperature of these closed circuits does not exceed the allowable temperature of the second switches 62U and 63U. The allowable temperature is, for example, the manufacturer's recommended value.

[0038] The "on period set so that the temperature of these closed circuits does not exceed the allowable temperature of the first switch 61U, and so that the temperature of these closed circuits does not exceed the allowable temperature of the second switches 62U, 63U" may be, for example, an on period assuming that the inductance of the windings 31U, 32U is at its maximum and the AC current flowing through the windings 31U, 32U is at its maximum value, or, assuming zero-cross switch control, an on period assuming that the inductance of the windings 31U, 32U is at its maximum and the AC current flowing through the windings 31U, 32U is at its minimum (for example, 0). The case in which the inductance of the windings 31U, 32U is at its maximum is when the windings 31U, 32U are connected in series.

[0039] Similarly, the control unit 70 switches the switching unit 60V between a first state and a second state, with an on period in between during which the first switch 61V and the second switches 62V, 63V are controlled to be in the ON state. The control unit 70 switches the switching unit 60W between a first state and a second state, with an on period in between during which the first switch 61W and the second switches 62W, 63W are controlled to be in the ON state.

[0040] When the control unit 70 switches the switching units 60U, 60V, and 60W between the first and second states, it does not switch all of them simultaneously, but switches them sequentially with a time interval between them. In other words, the control unit 70 staggers the switching timing to switch each switching unit 60U, 60V, and 60W between the first and second states. This prevents short circuits caused by the first and second switches of multiple switching units being turned on simultaneously.

[0041] As shown in Figure 2, the control unit 70 includes a control circuit 71, a first delay circuit 81, second delay circuits 82 and 83, and drive circuits 84, 85, and 86. In Figure 2, the control circuit 71, the first delay circuit 81, the second delay circuits 82 and 83, and the drive circuits 84, 85, and 86 are provided in correspondence to the U phase, but they are also provided separately in correspondence to the V phase and W phase. The operation of the U phase will be shown below as an example, but the operation of the V phase and W phase is similar.

[0042] The control circuit 71 switches between a first control state in which it outputs an ON signal to the first switch 61U and an OFF signal to the second switches 62U and 63U, and a second control state in which it outputs an OFF signal to the first switch 61U and an ON signal to the second switches 62U and 63U.

[0043] The control circuit 71 includes a signal output circuit 72, an output path 73, a first branch path 74, second branch paths 75 and 76, and inverting circuits 77 and 78. The signal output circuit 72 selectively outputs an ON signal and an OFF signal. The output signal from the signal output circuit 72 is output to the output path 73. The first branch path 74 branches off from the output path 73 and is located between the output path 73 and the first switch 61U. The second branch path 75 branches off from the output path 73 and is located between the output path 73 and the second switch 62U. The second branch path 76 branches off from the output path 73 and is located between the output path 73 and the second switch 63U. The inverting circuits 77 and 78 are circuits that invert the ON / OFF signals. The inverting circuit 77 is located in the second branch path 75. The inverting circuit 78 is located in the second branch path 76.

[0044] When the signal output circuit 72 outputs an on - signal, an on - signal is output from the first branch path 74 to the first switch 61U, the off - signal generated by the inversion circuit 77 is output to the second switch 62U, and the off - signal generated by the inversion circuit 78 is output to the second switch 63U. When the signal output circuit 72 outputs an off - signal, an off - signal is output from the first branch path 74 to the first switch 61U, the on - signal generated by the inversion circuit 77 is output to the second switch 62U, and the on - signal generated by the inversion circuit 78 is output to the second switch 63U. That is, the control circuit 71 is in the first control state when the signal output circuit 72 outputs an on - signal, and is in the second control state when the signal output circuit 72 outputs an off - signal.

[0045] The first delay circuit 81 delays only the off - signal among the on - off signals output from the control circuit 71 to the first switch 61U. The first delay circuit 81 includes a first resistor portion 81A, a first capacitor 81B, and a first diode 81C. The first resistor portion 81A is provided between the first branch path 74 of the control circuit 71 and the first switch 61U. The first capacitor 81B forms an RC circuit together with the first resistor portion 81A. The first diode 81C is connected in parallel to the first resistor portion 81A. The anode of the first diode 81C is electrically connected to the first branch path 74. The cathode of the first diode 81C is electrically connected to the conductive path on the first switch 61U side. The off - signal output from the control circuit 71 to the first switch 61U is delayed because it passes through the first resistor portion 81A. In contrast, the on - signal output from the control circuit 71 to the first switch 61U does not delay because it passes through the first diode 81C. The signal output from the first delay circuit 81 is input to the drive circuit 84, and the first switch 61U is driven by the drive circuit 84.

[0046] The second delay circuit 82 delays only the off signal from the on / off signal output from the control circuit 71 to the second switch 62U. The second delay circuit 82 includes a second resistor 82A, a second capacitor 82B, and a second diode 82C. The second resistor 82A is provided between the second branch line 75 of the control circuit 71 and the second switch 62U. The second capacitor 82B, together with the second resistor 82A, constitutes an RC circuit. The second diode 82C is connected in parallel with the second resistor 82A. The anode of the second diode 82C is electrically connected to the second branch line 75. The cathode of the second diode 82C is electrically connected to the conductive path on the second switch 62U side. The off signal output from the control circuit 71 to the second switch 62U is delayed because it passes through the second resistor 82A. In contrast, the on signal output from the control circuit 71 to the second switch 62U is not delayed because it passes through the second diode 82C. The signal output from the second delay circuit 82 is input to the drive circuit 85, and the drive circuit 85 drives the second switch 62U.

[0047] The second delay circuit 83 delays only the off signal from the on / off signal output from the control circuit 71 to the second switch 63U. The second delay circuit 83 includes a second resistor 83A, a second capacitor 83B, and a second diode 83C. The second resistor 83A is provided between the second branch line 76 of the control circuit 71 and the second switch 63U. The second capacitor 83B, together with the second resistor 83A, constitutes an RC circuit. The second diode 83C is connected in parallel with the second resistor 83A. The anode of the second diode 83C is electrically connected to the second branch line 76. The cathode of the second diode 83C is electrically connected to the conductive path on the second switch 63U side. The off signal output from the control circuit 71 to the second switch 63U is delayed because it passes through the second resistor 83A. In contrast, the on signal output from the control circuit 71 to the second switch 63U is not delayed because it passes through the second diode 83C. The signal output from the second delay circuit 83 is input to the drive circuit 86, and the drive circuit 86 drives the second switch 63U.

[0048] 1-3. Operating Example of Winding Switching Device 50 FIG. 3 shows a timing chart indicating the operations of the signal output circuit 72, the first delay circuit 81, the second delay circuits 82 and 83, the first switch 61U, and the second switches 62U and 63U when the connection states of the winding portions 31U and 32U are switched from the first state to the second state. At timing t1, the signal output circuit 72 outputs an on signal, the first delay circuit 81 outputs an on signal, the second delay circuits 82 and 83 output an off signal, the first switch 61U is in the on state, and the second switches 62U and 63U are in the off state (see FIG. 4). Thereafter, when the signal output circuit 72 outputs an off signal at timing t2, the output signals of the second delay circuits 82 and 83 are switched to on signals, and the second switches 62U and 63U are switched to the on state. As a result, as shown in FIG. 5, the first switch 61U and the second switches 62U and 63U are in the on state. Thereafter, when the output signal of the first delay circuit 81 is switched to an off signal at timing t3, the second switches 62U and 63U remain in the on state, and the first switch 61U is in the off state (see FIG. 6). That is, the connection state is switched to the second state.

[0049] FIG. 7 shows a timing chart indicating the operations of the signal output circuit 72, the first delay circuit 81, the second delay circuits 82 and 83, the first switch 61U, and the second switches 62U and 63U when the connection states of the winding portions 31U and 32U are switched from the second state to the first state. At timing t11, the signal output circuit 72 outputs an off signal, the first delay circuit 81 outputs an off signal, the second delay circuits 82 and 83 output an on signal, the first switch 61U is in the off state, and the second switches 62U and 63U are in the on state. Thereafter, when the signal output circuit 72 outputs an on signal at timing t12, the output signal of the first delay circuit 81 is switched to an on signal, and the first switch 61U and the second switches 62U and 63U are in the on state. Thereafter, when the output signals of the second delay circuits 82 and 83 are switched to off signals at timing t13, the first switch 61U remains in the on state, and the second switches 62U and 63U are in the off state. That is, the connection state is switched to the first state.

[0050] 1-4. Effects of the Winding Switching Device 50 The winding switching device 50 switches the switching section 60U, 60V, and 60W between a first state and a second state with an ON period in between, thereby preventing the first switch 61U and the second switches 62U, 63U from being in an OFF state and thus avoiding the generation of surge voltage. In other words, the winding switching device 50 can suppress the application of surge voltage to the first switch 61U and the second switches 62U, 63U that constitute the switching section 60U. The same applies to the V phase and W phase.

[0051] When the first switch 61U and the second switches 62U, 63U are switched to the ON state, a closed circuit is formed including the winding sections 31U, 32U, the first switch 61U, and the second switches 62U, 63U, and current flows back. Therefore, if the ON period is long, the first switch 61U and the second switches 62U, 63U may overheat and fail. In this regard, the winding switching device 50 is set so that the ON period is a time during which the temperature of the closed circuit does not exceed the allowable temperature of the first switch 61U, and also a time during which the temperature of the closed circuit does not exceed the allowable temperature of the second switches 62U, 63U. Therefore, it is possible to prevent the first switch 61U and the second switches 62U, 63U from failing due to overheating during the ON period. The same applies to the V phase and W phase.

[0052] When the control circuit 71 switches from the first control state to the second control state, the second delay circuits 82 and 83 immediately output the ON signal input from the control circuit 71, while the first delay circuit 81 outputs the OFF signal input from the control circuit 71 with a delay. Therefore, the first switch 61U and the second switches 62U and 63U remain ON until the OFF signal is output from the first delay circuit 81. Conversely, when the control circuit 71 switches from the second control state to the first control state, the first delay circuit 81 immediately outputs the ON signal input from the control circuit 71, while the second delay circuits 82 and 83 output the OFF signal input from the control circuit 71 with a delay. Therefore, the first switch 61U and the second switches 62U and 63U remain ON until the OFF signal is output from the second delay circuits 82 and 83. Thus, the winding switching device 50 can utilize the first delay circuit 81 and the second delay circuits 82 and 83 to create an ON period in which the first switch 61U and the second switches 62U and 63U are in the ON state. The same applies to the V phase and the W phase.

[0053] The winding switching device 50 allows for the simplification of the first delay circuit 81 and the second delay circuits 82 and 83.

[0054] 2. Second Embodiment In the first embodiment, a configuration for adjusting the on-time using a first delay circuit and a second delay circuit was described. In the second embodiment, a configuration for ending the on-time when it is confirmed that the first switch and the second switch have switched to the on state will be described. In the second embodiment, the only differences from the first embodiment are the configuration of the control unit and the fact that a voltage detection unit is provided. In the second embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed explanations are omitted.

[0055] The winding switching device 250 of the second embodiment, as shown in Figure 8, comprises a voltage detection unit 287 and a control unit 270. The voltage detection unit 287 detects the phase-to-phase voltage of the U phase. Specifically, the voltage detection unit 287 detects the voltage between the conductive path 21 and the neutral point 33. The signal indicating the phase-to-phase voltage of the U phase is input to the control unit 270. The voltage detection unit 287 is configured, for example, by a known voltage detection circuit.

[0056] The control unit 270 includes a control circuit 271 and drive circuits 84, 85, and 86. The control circuit 271 is configured to include, for example, an MCU. The control circuit 271 individually controls the on / off states of the first switch 61U and the second switches 62U and 63U by outputting on / off signals via the drive circuits 84, 85, and 86.

[0057] When the control circuit 271 switches the connection state of the winding sections 31U and 32U from the first state to the second state, it operates as follows: The control circuit 271 controls the connection state to the first state by controlling the first switch 61U to the ON state and the second switches 62U and 63U to the OFF state. When the conditions for switching to the second state are met, the control circuit 271 starts controlling the second switches 62U and 63U to the ON state. In other words, the control circuit 271 starts outputting an ON signal to the second switches 62U and 63U. The control circuit 271 then determines whether the first switch 61U and the second switches 62U and 63U are in the ON state. For example, the control circuit 271 determines whether the phase-to-phase voltage of the U phase is below a threshold during the ON period. When the first switch 61U and at least one of the second switches 62U and 63U are in the OFF state, current flows through at least one of the winding sections 31U and 32U, causing the phase-to-phase voltage to increase. In contrast, when the first switch 61U and the second switches 62U and 63U are all ON, the current does not pass through the windings 31U and 32U, but passes through the first switch 61U and the second switches 62U and 63U, so the phase voltage is near 0V. For this reason, the control circuit 271 determines that the first switch 61U and the second switches 62U and 63U are ON when the phase voltage falls below a threshold. The threshold is, for example, 0. When the control circuit 271 determines that the first switch 61U and the second switches 62U and 63U are ON, it switches the connection state to the second state.

[0058] When the control circuit 271 switches the connection state of the winding sections 31U and 32U from the second state to the first state, it operates as follows: The control circuit 271 controls the connection state to the second state by controlling the first switch 61U to the off state and the second switches 62U and 63U to the on state. When the conditions for switching to the first state are met, the control circuit 271 starts controlling the first switch 61U to the on state. In other words, the control circuit 271 starts outputting an on signal to the first switch 61U. The control circuit 271 then determines whether the first switch 61U and the second switches 62U and 63U have turned on. If the control circuit 271 determines that the first switch 61U and the second switches 62U and 63U have turned on, it switches the connection state to the first state.

[0059] The above description explains the switching of the U-phase switching unit 60U, but the same applies to the switching of the V-phase and W-phase.

[0060] As described above, the winding switching device 250 of the second embodiment can switch the connection state to the first state or the second state after confirming that the first switch 61U and the second switches 62U and 63U are in the ON state. The same applies to the V phase and W phase.

[0061] 3. Third Embodiment In the third embodiment, an example is described in which the ON period is terminated when the current flowing through the closed circuit exceeds the threshold current. In this third embodiment, the only differences from the first embodiment are the configuration of the control unit and the fact that a current detection unit is provided. In the third embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed explanations are omitted.

[0062] The winding switching device 350 of the third embodiment, as shown in Figure 9, comprises a current detection unit 387 and a control unit 370. When the first switch 61U and the second switch 62U are ON, a closed circuit 341 including the winding unit 31U, the first switch 61U, and the second switch 62U is formed. When the first switch 61U and the second switch 63U are ON, a closed circuit 342 including the winding unit 32U, the first switch 61U, and the second switch 63U is formed. The current detection unit 387 detects the current flowing through the common path 343 of the closed circuits 341 and 342. A signal indicating the detection result by the current detection unit 387 is input to the control unit 370. The current detection unit 387 is configured, for example, by a known current sensor.

[0063] The control unit 370 includes a control circuit 371 and drive circuits 84, 85, and 86. The control circuit 371 is configured to include, for example, an MCU. The control circuit 371 individually controls the on / off states of the first switch 61U and the second switches 62U and 63U by outputting on / off signals via the drive circuits 84, 85, and 86.

[0064] When the control circuit 371 switches the connection state of the winding sections 31U and 32U from the first state to the second state, it operates as follows: The control circuit 371 controls the connection state to the first state by controlling the first switch 61U to the ON state and the second switches 62U and 63U to the OFF state. When the conditions for switching to the second state are met, the control circuit 371 starts controlling the second switches 62U and 63U to the ON state. In other words, the control circuit 371 starts outputting an ON signal to the second switches 62U and 63U. The control circuit 371 then determines whether the current flowing through the common path 343 has exceeded the threshold current. If the control circuit 371 determines that the current flowing through the common path 343 has exceeded the threshold current, it ends the ON period and switches the connection state to the second state.

[0065] When the control circuit 371 switches the connection state of the winding sections 31U and 32U from the second state to the first state, it operates as follows: The control circuit 371 controls the connection state to the second state by controlling the first switch 61U to the off state and the second switches 62U and 63U to the on state. When the conditions for switching to the first state are met, the control circuit 371 starts controlling the first switch 61U to the on state. In other words, the control circuit 371 starts outputting an ON signal to the first switch 61U. The control circuit 371 then determines whether the current flowing through the common path 343 has exceeded the threshold current. If the control circuit 371 determines that the current flowing through the common path 343 has exceeded the threshold current, it ends the ON period and switches the connection state to the first state.

[0066] The above description explains the switching of the U-phase switching unit 60U, but the same applies to the switching of the V-phase and W-phase.

[0067] As described above, the winding switching device 350 of the third embodiment can terminate the ON period before the current flowing in common between the two closed circuits 341 and 342 becomes too large, and switch the connection state to the first state or the second state. The same applies to the V phase and the W phase.

[0068] 4. Fourth Embodiment In the first embodiment, the winding section was configured to switch between a series connection state and a parallel connection state. In contrast, the fourth embodiment describes a configuration in which the number of series connections in the winding section is switched. In the fourth embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed explanations are omitted.

[0069] The in-vehicle system 401 of the fourth embodiment, as shown in Figure 10, includes a battery 10, an inverter 11, a motor 430, and a winding switching device 450.

[0070] In this embodiment, motor 430 is a multiphase motor, specifically a three-phase motor. In this embodiment, motor 430 is Y-connected. Motor 430 has U-phase winding sections 431U, 432U, V-phase winding sections 431V, 432V, and W-phase winding sections 431W, 432W.

[0071] The winding switching device 450 includes switching sections 460U, 460V, and 460W, and a control unit 70. Switching section 460U corresponds to the U phase. Switching section 460U has a first switch 461U and a second switch 462U. Switching section 460V corresponds to the V phase. Switching section 460V has a first switch 461V and a second switch 462V. Switching section 460W corresponds to the W phase. Switching section 460W has a first switch 461W and a second switch 462W.

[0072] Winding sections 431U and 432U are provided between the conductive path 21 and the neutral point 33 so as to be connectable in series. A first switch 461U is positioned between the winding sections 431U and 432U. When the first switch 461U is ON, the winding sections 431U and 432U are connected in series. The second switch 462U is connected in parallel to the winding section 432U and the first switch 461U.

[0073] When the first switch 461U is ON and the second switch 462U is OFF, the switching unit 460U sets the connection state of the winding sections 431U and 432U to a first state. In the first state, the winding sections 431U and 432U are connected in series between the conductive path 21 and the neutral point 33, and the number of winding sections connected in series is 2. When the first switch 461U is OFF and the second switch 462U is ON, the switching unit 460U sets the connection state of the winding sections 431U and 432U to a second state. In the second state, only the winding section 431U is connected in series between the conductive path 21 and the neutral point 33, and the number of winding sections connected in series is 1.

[0074] Winding sections 431V and 432V are provided between the conductive path 22 and the neutral point 33 so as to be connectable in series. A first switch 461V is positioned between the winding sections 431V and 432V. When the first switch 461V is ON, the winding sections 431V and 432V are connected in series. The second switch 462V is connected in parallel to the winding section 432V and the first switch 461V.

[0075] When the first switch 461V is ON and the second switch 462V is OFF, the switching unit 460V sets the connection state of the windings 431V and 432V to the first state. In the first state, the windings 431V and 432V are connected in series between the conductive path 21 and the neutral point 33, and the number of windings connected in series is 2. When the first switch 461V is OFF and the second switch 462V is ON, the switching unit 460V sets the connection state of the windings 431V and 432V to the second state. In the second state, only the winding 431V is connected in series between the conductive path 22 and the neutral point 33, and the number of windings connected in series is 1.

[0076] Winding sections 431W and 432W are provided between the conductive path 23 and the neutral point 33 so as to be connectable in series. A first switch 461W is positioned between the winding sections 431W and 432W. When the first switch 461W is ON, the winding sections 431W and 432W are connected in series. The second switch 462W is connected in parallel to the winding section 432W and the first switch 461W.

[0077] When the first switch 461W is ON and the second switch 462W is OFF, the switching unit 460W sets the connection state of the winding sections 431W and 432W to the first state. In the first state, the winding sections 431W and 432W are connected in series between the conductive path 22 and the neutral point 33, and the number of winding sections connected in series is 2. When the first switch 461W is OFF and the second switch 462W is ON, the switching unit 460W sets the connection state of the winding sections 431W and 432W to the second state. In the second state, only the winding section 431W is connected in series between the conductive path 23 and the neutral point 33, and the number of winding sections connected in series is 1.

[0078] The control unit 70 switches the switching unit 460U between a first state and a second state, with an ON period in between during which the first switch 461U and the second switch 462U are controlled to be in the ON state. The control unit 70 switches the switching unit 460V between a first state and a second state, with an ON period in between during which the first switch 461V and the second switch 462V are controlled to be in the ON state. The control unit 70 switches the switching unit 460W between a first state and a second state, with an ON period in between during which the first switch 461W and the second switch 462W are controlled to be in the ON state.

[0079] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of the features of the embodiments described above or below is possible as long as it does not contradict the original. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. In addition, the embodiments described above may be modified as follows.

[0080] In the second embodiment described above, the control unit 270 was configured to determine whether the first switch 61U and the second switches 62U, 63U have been switched to the ON state based on the phase-to-phase voltage of the phase whose connection state is to be switched, but the configuration is not limited to this. For example, the control unit 270 may determine whether the first switch 61U and the second switches 62U, 63U have been switched to the ON state based on the phase-to-phase voltage of a phase that is energized but is different from the phase whose connection state is to be switched. When the first switch 61U and the second switches 62U, 63U are switched to the ON state in the phase whose connection state is to be switched, both ends of the phase whose connection state is to be switched are short-circuited, and this effect is transmitted to another phase that is energized. The control unit 270 can also determine whether the first switch 61U and the second switches 62U, 63U have been switched to the ON state based on the voltage that changes due to this effect. For similar reasons, the control unit 270 can also determine whether the first switch 61U and the second switches 62U, 63U have been switched to the ON state based on the line voltage between the conductive path on the inverter 11 side of the phase whose connection state is to be switched and the conductive path on the inverter 11 side of another phase that is in an energized state. Alternatively, the control unit 270 can also determine whether the first switch 61U and the second switches 62U, 63U have been switched to the ON state based on the voltage across both ends of the winding section 31U and the voltage across both ends of the winding section 32U.

[0081] In the second embodiment described above, the control unit 270 may terminate the ON period after a predetermined time has elapsed since starting control to turn on the first switch 61U and the second switches 62U, 63U, and control the connection state to the first state or the second state.

[0082] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is indicated by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0083] 1...In-vehicle system 10...Battery 11...Inverter 12...Switching element 13...Switching element 14...Switching element 15...Switching element 16...Switching element 17...Switching element 21...Conductive circuit 22...Conductive circuit 23...Conductive circuit 30...Motor 31U...Winding section 31V...Winding section 31W...Winding section 32U...Winding section 32V...Winding section 32W...Winding section 33...Neutral point 50...Winding switching device 60U...Switching section 60V...Switching section 60W...Switching section 61U...First switch 61V...First switch 61W...First switch 62U...Second switch 62V...Second switch 62W...Second switch 63U...Second switch 63V...Second switch 63W...Second switch 70...Control unit 71...Control circuit 72...Signal output circuit 73...Output path 74...First branch path 75...Second branch path 76...Second branch path 77...Inverting circuit 78...Inverting circuit 81...First delay circuit 81A...First resistor section 81B...First capacitor 81C...First diode 82...Second delay circuit 82A...Second resistor section 82B...Second capacitor 82C...Second diode 83...Second delay circuit 83A...Second resistor section 83B...Second capacitor 83C...Second diode 84...Drive circuit 85...Drive circuit 86...Drive circuit 91...Positive electrode conductive path 92...Negative electrode conductive path 250...Winding switching device 270...Control unit 271...Control circuit 287...Voltage detection unit 341...Closed circuit 342...Closed circuit 343...Common path 350...Winding switching device 370...Control unit 371...Control circuit 387...Current detection unit 401...In-vehicle system 430...Motor 431U...Winding unit 431V...Winding unit 431W...Winding unit 432U...Winding unit 432V...Winding unit 432W...Winding unit 450...Winding switching device 460U...Switching unit 460V...Switching unit 460W...Switching unit 461U...First switch 461V...First switch 461W...First switch 462U...Second switch 462V...Second switch 462W...Second switch

Claims

A winding switching device used in a motor that includes multiple winding sections, A switching unit that switches the connection state of multiple winding sections between a first state and a second state, The system comprises a control unit that controls the switching unit, The switching unit has a first switch and a second switch, and the connection state becomes the first state when the first switch is ON and the second switch is OFF, and the connection state becomes the second state when the first switch is OFF and the second switch is ON. The first switch and the second switch are positioned to form a closed circuit including the winding section, the first switch, and the second switch when they are each in the ON state. The control unit switches the switching unit between the first state and the second state, with an ON period in between during which the first switch and the second switch are controlled to the ON state. Winding switching device. 　 The ON period is set to a time during which the temperature of the closed circuit does not exceed the allowable temperature of the first switch, and the temperature of the closed circuit does not exceed the allowable temperature of the second switch. The winding switching device according to claim 1. 　 The control unit, Control circuit and A first delay circuit provided in correspondence with the first switch, It includes a second delay circuit provided in correspondence with the second switch, The control circuit switches between a first control state in which it outputs an ON signal to the first switch and an OFF signal to the second switch, and a second control state in which it outputs an OFF signal to the first switch and an ON signal to the second switch. The first delay circuit delays only the off signal among the on / off signals output from the control circuit to the first switch. The second delay circuit delays only the off signal from the on / off signal output from the control circuit to the second switch. A winding switching device according to claim 1 or claim 2. 　 The first delay circuit is, A first resistor is provided between the control circuit and the first switch, A first capacitor, which together with the first resistor, constitutes an RC circuit, It includes a first diode connected in parallel with the first resistor, The anode of the first diode is electrically connected to the conductive path on the control circuit side. The cathode of the first diode is electrically connected to the conductive path on the first switch side. The second delay circuit is, A second resistor is provided between the control circuit and the second switch, A second capacitor, which together with the second resistor, constitutes an RC circuit, It includes a second diode connected in parallel with the second resistor, The anode of the second diode is electrically connected to the conductive path on the control circuit side. The cathode of the second diode is electrically connected to the conductive path on the second switch side. The winding switching device according to claim 3. 　 After the control unit starts controlling the first switch and the second switch to be turned on, if it determines that the first switch and the second switch are turned on, it terminates the on period and controls the connection state to the first state or the second state. The winding switching device according to claim 1. 　 After the control unit starts controlling the first switch and the second switch to the ON state, if it determines that the current flowing through the closed circuit exceeds the threshold current, it terminates the ON period and controls the connection state to the first state or the second state. The winding switching device according to claim 1. 　 At least two of the second switches are provided. Each of the second switches forms a separate closed circuit with the first switch. After the control unit starts controlling the first switch and the second switch to the ON state, if it determines that the current flowing through the common path of the separate closed circuits exceeds the threshold current, it terminates the ON period and controls the connection state to the first state or the second state. The winding switching device according to claim 6.

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