Winding switching device
The winding switching device addresses unintended closed circuit formation in motors by using a dual-switch configuration with a dead time mechanism and delay circuits to manage surge voltages, ensuring reliable operation and switch protection.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AUTONETWORKS TECH LTD
- Filing Date
- 2026-01-06
- Publication Date
- 2026-07-23
AI Technical Summary
Existing winding switching devices in motors are prone to forming unintended closed circuits due to variations in relay switch performance or control timing, leading to potential overcurrent issues.
A winding switching device with a switching section and control section that utilizes a first and second switch configuration, along with a dead time mechanism, to prevent the formation of closed circuits by ensuring the switches are not simultaneously in the on state, and incorporates delay circuits and snubber circuits to manage surge voltages.
Prevents the formation of unintended closed circuits and protects the switches from surge voltages by maintaining the switches in an off state during dead time, thereby preventing switch failure and ensuring reliable operation.
Smart Images
Figure JP2026000119_23072026_PF_FP_ABST
Abstract
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 Patent Application Laid-Open 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 be in the on state temporarily due to variations in the performance of each device or variations in control timing. In this case, a closed circuit may be formed by the first relay switch, the second relay switch, and the second coil unit, and current may flow back, resulting in the possibility of an overcurrent flowing.
[0005] An object of the present disclosure is to provide a technique capable of preventing the formation of an unintended closed circuit.
[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, assuming that each is ON, and the control section switches the switching section between the first state and the second state with a dead time in between for controlling the first switch and the second switch to the OFF state.
[0007] According to the technology disclosed herein, it is possible to prevent the formation of unintended closed circuits.
[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 dead time. Figure 6 is an explanatory diagram showing the operation of the winding switching device after 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. Figure 11 is a schematic diagram showing an in-vehicle system equipped with a winding switching device according to the fifth 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, assuming that each is ON, and the control section switches the switching section between the first state and the second state with a dead time in between for controlling the first switch and the second switch to the OFF state.
[0011] The above-described winding switching device switches the switching section between a first state and a second state with a dead time in between, thus avoiding the formation of a closed circuit due to the first and second switches being in the ON state. In other words, the above-described winding switching device prevents the formation of an unintended closed circuit.
[0012] [2] The winding switching device according to [1], wherein the dead time is set to a time during which the voltage across the first switch does not exceed the withstand voltage of the first switch, and the voltage across the second switch does not exceed the withstand voltage of the second switch.
[0013] When the first and second switches are switched to the off state, surge voltages are applied to both ends of the first and second switches. Therefore, if the dead time is long, the first and second switches may fail. In this regard, the winding switching device described above has a dead time set so that the voltage across the first switch does not exceed the withstand voltage of the first switch, and the voltage across the second switch does not exceed the withstand voltage of the second switch. Therefore, it is possible to prevent the first and second switches from failing due to surge voltages during the dead time.
[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 ON signal of the ON / OFF signal output from the control circuit to the first switch, and the second delay circuit delays only the ON 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 first delay circuit immediately outputs the off signal input from the control circuit, and the second delay circuit outputs the on signal input from the control circuit with a delay. Therefore, the first and second switches remain in the off state until the on signal is output from the second delay circuit. Conversely, when the control circuit switches from the second control state to the first control state, the first delay circuit outputs the on signal input from the control circuit with a delay, and the second delay circuit immediately outputs the off signal input from the control circuit. Therefore, the first and second switches remain in the off state until the on signal is output from the first delay circuit. In this way, the above-described winding switching device can utilize the first and second delay circuits to create a dead time during which the first and second switches are in the off state.
[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 first switch side, and the cathode of the first diode is electrically connected to the conductive path on the control circuit 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 second switch side, and the cathode of the second diode is electrically connected to the conductive path on the control circuit side. The winding switching device according to [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 determines that the voltage of a predetermined portion affected by the surge voltage generated when the first switch and the second switch are controlled to the off state exceeds a threshold during the dead time, and switches the connection state to the first state or the second state.
[0019] According to the above-described winding switching device, the dead time can be terminated before the surge voltage applied to the first and second switches becomes too large, and the connection state can be switched to the first state or the second state.
[0020] [6] The winding switching device according to [5], wherein the control unit determines that at least one of the voltages across the first switch and the voltages across the second switch exceeds the threshold during the dead time, and switches the connection state to the first state or the second state.
[0021] According to the above-described winding switching device, the dead time can be terminated when at least one of the voltages across the first switch and the voltages across the second switch exceeds a threshold, and the connection state can be switched to the first state or the second state.
[0022] [7] A winding switching device according to any one of [1] to [6], comprising a snubber circuit connected in parallel to at least one of the first switch and the second switch.
[0023] According to the above-described winding switching device, the snubber circuit can absorb the surge voltage that occurs when the first switch and the second switch are controlled to the off 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 a dead time in between that controls the first switch 61U and the second switches 62U and 63U to the off state. The dead time is set to a time during which the voltage across the first switch 61U does not exceed the withstand voltage of the first switch 61U, and the voltage across the second switches 62U and 63U does not exceed the withstand voltage of the second switches 62U and 63U. The withstand voltage is, for example, the manufacturer's recommended value.
[0038] The "dead time, set so that the voltage across the first switch 61U does not exceed the withstand voltage of the first switch 61U, and the voltage across the second switches 62U and 63U does not exceed the withstand voltage of the second switches 62U and 63U" may be, for example, a dead time assuming the case where the inductance of the windings 31U and 32U is at its maximum and the AC current flowing through the windings 31U and 32U is at its maximum, or, assuming zero-cross switch control, a dead time assuming the case where the inductance of the windings 31U and 32U is at its maximum and the AC current flowing through the windings 31U and 32U is at its minimum (for example, 0). The case in which the inductance of the windings 31U and 32U is at its maximum is when the windings 31U and 32U are connected in series.
[0039] Similarly, the control unit 70 switches the switching unit 60V between the first state and the second state, with a dead time in between during which the first switch 61V and the second switches 62V, 63V are controlled to the off state. The control unit 70 switches the switching unit 60W between the first state and the second state, with a dead time in between during which the first switch 61W and the second switches 62W, 63W are controlled to the off state. When the control unit 70 switches the switching units 60U, 60V, and 60W between the first state and the second state, it does not switch all the switching units 60U, 60V, and 60W simultaneously, but switches them sequentially with a time interval in between. In other words, the control unit 70 switches each switching unit 60U, 60V, and 60W between the first state and the second state by staggering the switching timing.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] When the signal output circuit 72 is outputting an ON signal, an ON signal is output from the first branch 74 to the first switch 61U, the OFF signal generated by the inverting circuit 77 is output to the second switch 62U, and the OFF signal generated by the inverting circuit 78 is output to the second switch 63U. When the signal output circuit 72 is outputting an OFF signal, an OFF signal is output from the first branch 74 to the first switch 61U, the ON signal generated by the inverting circuit 77 is output to the second switch 62U, and the ON signal generated by the inverting circuit 78 is output to the second switch 63U. In other words, the control circuit 71 is in a first control state when the signal output circuit 72 is outputting an ON signal, and is in a second control state when the signal output circuit 72 is outputting an OFF signal.
[0044] The first delay circuit 81 delays only the on 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 constitutes 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 conductive path on the first switch 61U side. The cathode of the first diode 81C is electrically connected to the first branch path 74. The on 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 off signal output from the control circuit 71 to the first switch 61U is not delayed 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.
[0045] The second delay circuit 82 delays only the on signal among the on / off signals output from the control circuit 71 to the second switch 62U. The second delay circuit 82 includes a second resistor portion 82A, a second capacitor 82B, and a second diode 82C. The second resistor portion 82A is provided between the second branch path 75 of the control circuit 71 and the second switch 62U. The second capacitor 82B constitutes an RC circuit together with the second resistor portion 82A. The second diode 82C is connected in parallel to the second resistor portion 82A. The anode of the second diode 82C is electrically connected to the conductive path on the second switch 62U side. The cathode of the second diode 82C is electrically connected to the second branch path 75. The on signal output from the control circuit 71 to the second switch 62U is delayed because it passes through the second resistor portion 82A. In contrast, the off 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 second switch 62U is driven by the drive circuit 85.
[0046] The second delay circuit 83 delays only the ON 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 conductive path on the second switch 63U side. The cathode of the second diode 83C is electrically connected to the second branch line 76. The ON 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 OFF 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.
[0047] 1-3. Operation Example of Winding Switching Device 50 Figure 3 shows a timing chart illustrating the operation of the signal output circuit 72, the first delay circuit 81, the second delay circuits 82, 83, the first switch 61U, and the second switches 62U, 63U when the connection state of the winding sections 31U, 32U switches 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, 83 output OFF signals, the first switch 61U is in the ON state, and the second switches 62U, 63U are in the OFF state (see Figure 4). Subsequently, at timing t2, when the signal output circuit 72 outputs an OFF signal, the output signal of the first delay circuit 81 switches to an OFF signal, and the first switch 61U switches to the OFF state. As a result, as shown in Figure 5, the first switch 61U and the second switches 62U, 63U are in the OFF state. Subsequently, at timing t3, when the output signals of the second delay circuits 82 and 83 are switched to ON signals, the first switch 61U remains OFF while the second switches 62U and 63U turn ON (see Figure 6). In other words, the connection state switches to the second state.
[0048] Figure 7 shows a timing chart illustrating 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 switch 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 on signals, the first switch 61U is in an off state, and the second switches 62U and 63U are in on states. Thereafter, when the signal output circuit 72 outputs an on signal at timing t12, the output signals of the second delay circuits 82 and 83 switch to off signals, and the first switch 61U and the second switches 62U and 63U become off states. Thereafter, when the output signal of the first delay circuit 81 switches to an on signal at timing t13, with the second switches 62U and 63U remaining in off states, the first switch 61U becomes in an on state. That is, the connection state switches to the first state.
[0049] 1-4. Effects of the winding switching device 50 The winding switching device 50 switches the switching units 60U, 60V, and 60W between the first state and the second state with a dead time interposed therebetween, so that it is possible to avoid the first switch 61U and the second switches 62U and 63U from being in on states to form a closed circuit, it is possible to avoid the first switch 61V and the second switches 62V and 63V from being in on states to form a closed circuit, and it is possible to avoid the first switch 61W and the second switches 62W and 63W from being in on states to form a closed circuit. That is, according to the winding switching device 50, it is possible to prevent an unintentional closed circuit from being formed.
[0050] When the first switches 61U, 61V, 61W and the second switches 62U, 62V, 62W, 63U, 63V, 63W are switched to the off state, surge voltages are applied to both ends of the first switches 61U, 61V, 61W and both ends of the second switches 62U, 62V, 62W, 63U, 63V, 63W. Therefore, if the dead time is long, both ends of the first switches 61U, 61V, 61W and both ends of the second switches 62U, 62V, 62W, 63U, 63V, 63W may fail. In this regard, the winding switching device 50 is set so that the voltage across the first switches 61U, 61V, and 61W does not exceed the withstand voltage of the first switches 61U, 61V, and 61W, and the voltage across the second switches 62U, 62V, 62W, 63U, 63V, and 63W does not exceed the withstand voltage of the second switches. Therefore, it is possible to prevent the first switches 61U, 61V, and 61W and the second switches 62U, 62V, 62W, 63U, 63V, and 63W from failing due to surge voltage during the dead time.
[0051] When the control circuit 71 switches from the first control state to the second control state, the first delay circuit 81 immediately outputs the off signal input from the control circuit 71, and the second delay circuits 82 and 83 output the on signal input from the control circuit 71 with a delay. Therefore, the first switch 61U and the second switches 62U and 63U remain in the off state until the on signal is output from the second delay circuits 82 and 83. Conversely, when the control circuit 71 switches from the second control state to the first control state, the first delay circuit 81 outputs the on signal input from the control circuit 71 with a delay, and the second delay circuits 82 and 83 immediately output the off signal input from the control circuit 71. Therefore, the first switch 61U and the second switches 62U and 63U remain in the off state until the on signal is output from the first delay circuit 81. Thus, the winding switching device 50 can utilize the first delay circuit 81 and the second delay circuits 82, 83 to create a dead time in which the first switch 61U and the second switches 62U, 63U are in the off state, a dead time in which the first switch 61V and the second switches 62V, 63V are in the off state, and a dead time in which the first switch 61W and the second switches 62W, 63W are in the off state.
[0052] The winding switching device 50 allows for the simplification of the first delay circuit 81 and the second delay circuits 82 and 83.
[0053] 2. Second Embodiment In the first embodiment, a configuration for adjusting the dead time using a first delay circuit and a second delay circuit was described. In the second embodiment, a configuration for ending the dead time when the surge voltage generated when the switch is turned off exceeds a certain level 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.
[0054] The winding switching device 250 of the second embodiment, as shown in Figure 8, includes a voltage detection unit 287 and a control unit 270. The voltage detection unit 287 detects the voltage across the first switch 61U. A signal indicating the voltage across the first switch 61U is input to the control unit 270. The voltage detection unit 287 is configured, for example, by a known voltage detection circuit.
[0055] 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.
[0056] 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 switches the first switch 61U to the OFF state and controls the first switch 61U and the second switches 62U and 63U to the OFF state. As a result, the switching section 60U enters a dead time. During the dead time, the control circuit 271 monitors the voltage across the first switch 61U and switches the connection state to the second state if it determines that the voltage across the first switch 61U exceeds a threshold. The threshold is set so that the voltage across the first switch 61U does not exceed the withstand voltage of the first switch 61U, and the voltage across the second switches 62U and 63U does not exceed the withstand voltage of the second switches 62U and 63U.
[0057] 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 switches the second switches 62U and 63U to the off state and controls the first switch 61U and the second switches 62U and 63U to the off state. As a result, the switching section 60U enters a dead time. During the dead time, the control circuit 271 monitors the voltage across the first switch 61U and, if it determines that the voltage across the first switch 61U exceeds a threshold, it switches the connection state to the first state.
[0058] 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.
[0059] According to the winding switching device 250 of the second embodiment, the dead time can be terminated when the voltage across the first switch 61U exceeds a threshold, and the connection state can be switched to the first state or the second state.
[0060] 3. Third Embodiment The third embodiment will describe a configuration that includes a snubber circuit. The winding switching device of the third embodiment has the same configuration as the winding switching device of the first embodiment, except that it includes a snubber circuit. 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.
[0061] The winding switching device 350 of the third embodiment includes a switching unit 60U and a snubber circuit 387, as shown in Figure 9. The snubber circuit 387 is connected in parallel to the first switch 61U of the switching unit 60U. In Figure 9, the U phase is shown as an example, but the snubber circuit 387 is similarly connected to the V phase and W phase as well.
[0062] According to the winding switching device 350 of the third embodiment, the snubber circuit 387 can absorb the surge voltage that occurs when the first switch 61U and the second switches 62U and 63U are controlled to the off state.
[0063] 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.
[0064] 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.
[0065] 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.
[0066] 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.
[0067] 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.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] The control unit 70 switches the switching unit 460U between a first state and a second state, with a dead time in between for controlling the first switch 461U and the second switch 462U to the off state. The control unit 70 switches the switching unit 460V between a first state and a second state, with a dead time in between for controlling the first switch 461V and the second switch 462V to the off state. The control unit 70 switches the switching unit 460W between a first state and a second state, with a dead time in between for controlling the first switch 461W and the second switch 462W to the off state.
[0074] 5. Fifth Embodiment In the fifth embodiment, a configuration that switches between a Y connection and a delta connection will be described. In the fifth embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed explanations are omitted.
[0075] The in-vehicle system 501 of the fifth embodiment, as shown in Figure 11, includes a battery 10, an inverter 11, a motor 530, and a winding switching device 550.
[0076] Motor 530 is a three-phase motor. Motor 530 has winding sections 531, 532, and 533.
[0077] The winding switching device 550 includes a switching unit 560 and a control unit 70. The switching unit 560 includes first switches 561, 562, 563 and second switches 564, 565, 566.
[0078] One end of the winding section 531 and one end of the second switch 564 are electrically connected to the conductive path 21. One end of the winding section 532 and one end of the second switch 565 are electrically connected to the conductive path 22. One end of the winding section 533 and one end of the second switch 566 are electrically connected to the conductive path 23. The other end of the winding section 531 is electrically connected to the other end of the second switch 566 and one end of the first switch 561. The other end of the winding section 532 is electrically connected to the other end of the second switch 564 and one end of the first switch 562. The other end of the winding section 533 is electrically connected to the other end of the second switch 565 and one end of the first switch 563. The other end of the first switch 561, the other end of the first switch 562, and the other end of the first switch 563 are electrically connected to each other.
[0079] The switching unit 560 sets the connection state of the winding units 531, 532, and 533 to a first state when the first switches 561, 562, and 563 are ON and the second switches 564, 565, and 566 are OFF. The first state is a state in which a Y connection is formed.
[0080] The switching unit 560 sets the connection state of the winding sections 531, 532, and 533 to a second state when the first switches 561, 562, and 563 are in the off state and the second switches 564, 565, and 566 are in the on state. The second state is a state in which a delta connection is formed.
[0081] The control unit 70 switches the switching unit 560 between the first state and the second state, with a dead time in between during which the first switches 561, 562, 563 and the second switches 564, 565, 566 are controlled to the off state.
[0082] <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.
[0083] In the first to fourth embodiments described above, the motor may be a single-phase motor.
[0084] In the second embodiment described above, the control unit was configured to switch the connection state to the first state or the second state when it determined that the voltage across the first switch exceeded a threshold during the dead time. In other words, the target of the determination was the voltage across the first switch. However, the target of the determination may be any predetermined portion of the voltage affected by the surge voltage that occurs when the first and second switches are controlled to the off state. For example, it may be the voltage across the second switch, or the voltage across the phase in which the first and second switches are in the off state (i.e., the potential difference between any of the conductive paths 21, 22, or 23 and the neutral point 33; phase-to-phase voltage), or the potential difference between the conductive path on the inverter side of the first phase and the conductive path on the inverter side of the second phase when the first or second switch of the first phase is in the ON state and the first and second switches of the second phase are in the OFF state (i.e., line-to-line voltage).
[0085] In the second embodiment described above, the control unit may terminate the dead time after a predetermined time has elapsed since controlling the first switch and the second switch to the off state, and control the connection state to the first state or the second state.
[0086] In the third embodiment described above, the snubber circuit was connected in parallel to the first switch. In contrast, the snubber circuit may be connected in parallel to the second switch, or it may be connected in parallel to both the first switch and the second switch.
[0087] 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.
[0088] 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 350...Winding switching device 387...Snubber circuit 401...In-vehicle system 430...Motor 431U...Winding section 431V...Winding section 431W...Winding section 432U...Winding section 432V...Winding section 432W...Winding section 450...Winding switching device 460U...Switching section 460V...Switching section 460W...Switching section 461U...First switch 461V...First switch 461W...First switch 462U...Second switch 462V...Second switch 462W...Second switch 501...Automotive system 530...Motor 531...Winding section 532...Winding section 533...Winding section 550...Winding switching device 560...Switching section 561...First switch 562...First switch 563...First switch 564...Second switch 565...Second switch 566...Second switch
Claims
1. A winding switching device for use in a motor including a plurality of winding sections, comprising: a switching section for switching the connection state of the plurality of winding sections between a first state and a second state; and a control section for controlling 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, assuming that each is ON, and the control section switches the switching section between the first state and the second state with a dead time in between for controlling the first switch and the second switch to the OFF state.
2. The winding switching device according to claim 1, wherein the dead time is set to a time during which the voltage across the first switch does not exceed the withstand voltage of the first switch, and the voltage across the second switch is set to a time during which the voltage across the second switch does not exceed the withstand voltage of the second switch.
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 ON signal of the ON / OFF signal output from the control circuit to the first switch, and the second delay circuit delays only the ON signal of the ON / OFF signal output from the control circuit to the second switch, the winding switching device according to claim 1 or claim 2.
4. The winding switching device according to claim 3, wherein the first delay circuit comprises a first resistor provided between the control circuit and the first switch, a first capacitor that constitutes an RC circuit together with the first resistor, and a first diode connected in parallel with the first resistor, the anode of the first diode being electrically connected to the conductive path on the first switch side, and the cathode of the first diode being electrically connected to the conductive path on the control circuit side; the second delay circuit comprises a second resistor provided between the control circuit and the second switch, a second capacitor that constitutes an RC circuit together with the second resistor, and a second diode connected in parallel with the second resistor, the anode of the second diode being electrically connected to the conductive path on the second switch side, and the cathode of the second diode being electrically connected to the conductive path on the control circuit side.
5. The winding switching device according to claim 1, wherein the control unit determines that the voltage of a predetermined portion affected by the surge voltage generated when the first switch and the second switch are controlled to the off state exceeds a threshold during the dead time, and switches the connection state to the first state or the second state.
6. The winding switching device according to claim 5, wherein the control unit determines that at least one of the voltages across the first switch and the voltages across the second switch exceeds the threshold during the dead time, and switches the connection state to the first state or the second state.
7. The winding switching device according to claim 1 or claim 2, further comprising a snubber circuit connected in parallel to at least one of the first switch and the second switch.