Power supply system

Abstract

Reduce manufacturing cost SOLUTION: A switch provided between a first power supply line connecting the first power conversion circuit and the first load and a second power supply line connecting the second power conversion circuit and the second load, a switch provided between a third power supply line connecting the first power conversion circuit and the first load and a fourth power supply line connecting the second power conversion circuit and the second load, and a second power supply connected to the first power supply line, in the non-starting state of the electric vehicle, the first power conversion circuit converts the voltage of 48V supplied from the second power source into the voltage of 12V, the two switches are controlled to be in the connected state, the voltage of 48V output from the second power source is supplied to the first load and the first power conversion circuit and is supplied to the second load via the switch, and the voltage of 12V output from the first power conversion circuit is supplied to the first load and is supplied to the second load via the switch.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a power supply system mounted on a vehicle. [Background technology]

[0002] In recent years, there has been a need to improve road safety in order to make cities and human settlements inclusive, safe, resilient, and sustainable. From the perspective of improving road safety, it is necessary to ensure road safety even when a vehicle malfunctions.

[0003] Patent Document 1 describes a vehicle power supply system that includes a main power supply system having a normal load group and an auxiliary power supply, a backup power supply system having a backup load group, and a high-voltage power supply that outputs power at a higher voltage than the auxiliary power supply, wherein the main power supply system is connected to the high-voltage power supply via a first DC / DC converter, and the backup power supply system is connected to the high-voltage power supply in parallel with the main power supply system via a second DC / DC converter, and further includes a connection line that connects the main power supply system and the backup power supply system.

[0004] Patent Document 2 describes a power conversion device that has a main DC / DC converter that performs voltage conversion between a first voltage section and a second voltage section, and a power conversion unit connected to the first voltage section, the power conversion unit having a power conversion section that performs power conversion between the first voltage section and a third voltage section, and a sub DC / DC converter that shares at least a part of the power conversion section with the power conversion section as a shared component, and the sub DC / DC converter is connected in parallel with the main DC / DC converter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-32346 [Patent Document 2] Japanese Patent Publication No. 2020-61807 Summary of the Invention [Problem to be solved by the invention]

[0006] The technology of the present disclosure aims to provide a vehicle power supply system that can reduce manufacturing costs. [Means for solving the problem]

[0007] The technology disclosed herein provides a power supply system including a first power conversion circuit and a second power conversion circuit connected in parallel to a first power source mounted on a vehicle and capable of outputting a first level voltage, the first power conversion circuit and the second power conversion circuit being capable of converting the first level voltage to a second level voltage and a third level voltage, respectively, and converting the second level voltage to the third level voltage, the second level voltage and the third level voltage output from the first power conversion circuit being configured to be able to be supplied to a first load of the vehicle, and the second level voltage and the third level voltage output from the second power conversion circuit being configured to be able to be supplied to a second load of the vehicle, a power supply line through which the second level voltage is supplied, the first switch being capable of switching between connection and disconnection between a first power supply line connecting the first power conversion circuit and the first load and a second power supply line connecting the second power conversion circuit and the second load, and a power supply line through which the third level voltage is supplied, the first power conversion circuit and the second power conversion circuit being configured to be able to switch between connection and disconnection between the first power supply line connecting the first power conversion circuit and the first load and the second power supply line connecting the second power conversion circuit and the second load. the second power supply system further includes a second switch capable of switching between connection and disconnection between a third power supply line connecting a conversion circuit and the first load and a fourth power supply line connecting the second power conversion circuit and the second load; and a second power supply connected to the first power supply line and capable of outputting the second level voltage, wherein, when the vehicle is in a non-started state, the first power conversion circuit operates in a first mode in which the first power conversion circuit converts the second level voltage supplied from the second power supply into the third level voltage, the first switch and the second switch are each controlled to a connected state, the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit, the second level voltage output from the second power supply is supplied to the second load via the first switch, the third level voltage output from the first power conversion circuit is supplied to the first load, and the third level voltage output from the first power conversion circuit is supplied to the second load via the second switch. [Effects of the Invention]

[0008] According to the technology of the present disclosure, it is possible to provide a vehicle power supply system that can reduce manufacturing costs. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of a power supply system 100. As shown in FIG. [Figure 2] FIG. 2 is a schematic diagram showing the internal configuration of the first DC / DC converter 41. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing the flow of power in the first DC / DC converter 41 when operating in the first mode. [Figure 4] FIG. 4 is a diagram showing the flow of power in the first DC / DC converter 41 when operating in the second mode. [Figure 5] FIG. 5 is a diagram showing the flow of power in the first DC / DC converter 41 when operating in the third mode. [Figure 6] FIG. 6 is a diagram illustrating the operation of power supply system 100 when the vehicle is in a startup state. [Figure 7] FIG. 7 is a diagram illustrating the flow of power when an abnormality occurs in the second DC / DC converter 42 in the normal startup state shown in FIG. 6, making it impossible for the second DC / DC converter 42 to perform appropriate power conversion. [Figure 8] FIG. 8 is a diagram illustrating the flow of power when an abnormality occurs in the first DC / DC converter 41 in the normal startup state shown in FIG. 6, making it impossible for the first DC / DC converter 41 to perform appropriate power conversion. [Figure 9] FIG. 9 is a diagram illustrating the flow of power when an abnormality occurs in the high-voltage power supply 30 in the normal startup state shown in FIG. 6, and the high-voltage power supply 30 is unable to supply appropriate power. [Figure 10] FIG. 10 is a diagram illustrating another example of the flow of power when an abnormality occurs in the high-voltage power supply 30 in the normal startup state shown in FIG. 6 and the high-voltage power supply 30 is unable to supply appropriate power. [Figure 11] FIG. 11 is a diagram illustrating the flow of power when a short circuit occurs in the second DC / DC converter 42 in the normal startup state shown in FIG. [Figure 12]FIG. 12 is a diagram illustrating the flow of power when a short circuit occurs in the first DC / DC converter 41 in the normal startup state shown in FIG. [Figure 13] FIG. 13 is a diagram illustrating the flow of power when the vehicle is in a non-start state. [Figure 14] FIG. 14 is a diagram illustrating the flow of power when the mode of the first DC / DC converter 41 is switched from the state shown in FIG. 13 to the second mode. [Figure 15] FIG. 15 is a diagram illustrating the flow of power when the vehicle transitions from a non-startup state to an activation state. DETAILED DESCRIPTION OF THE INVENTION

[0010] A vehicle power supply system 100 according to an embodiment of the technology of the present disclosure will be described below with reference to the accompanying drawings. The drawings are to be read in the direction indicated by the reference numerals. FIG. 1 is a schematic diagram showing the general configuration of the power supply system 100.

[0011] The power supply system 100 is mounted on a vehicle such as an automobile. The vehicle is provided with a high-voltage power supply 30 capable of outputting a voltage of a first level L1 (for example, 400 [V] or 800 [V]), a normal load group 11, and a backup load group 21. The high-voltage power supply 30 supplies power to a motor that drives the wheels of the vehicle, and also supplies power to the normal load group 11 and the backup load group 21. The high-voltage power supply 30 is configured to include a secondary battery such as a lithium-ion battery or an all-solid-state battery.

[0012] The normal load group 11 includes loads that perform functions related to the vehicle's running operation, stopping operation, or driving control. For example, the normal load group 11 includes at least one of an auxiliary load used for vehicle driving control such as an ECU (Electronic Control Unit), an auxiliary load used for vehicle braking such as an automatic braking device, an auxiliary load used for vehicle steering such as an automatic steering device, and an auxiliary load used for acquiring external information about the vehicle such as a LiDAR (Light Detection and Ranging) or an imaging device.

[0013] In this embodiment, the normal load group 11 includes an ECU 111 used to control the operation of the vehicle, an automatic brake control device 112 that controls the braking device used to brake the vehicle, an automatic steering control device 113 that controls the steering device used to steer the vehicle, and an external environment information processing device 114 that processes input information from a LiDAR or an imaging device used to acquire external environment information for the vehicle.

[0014] Furthermore, the normal load group 11 includes auxiliary loads 117, which are auxiliary loads other than those used for vehicle operation control, braking, steering, and acquiring external information about the vehicle. The auxiliary loads 117 include, for example, headlights, wiper units, power window units, and meters. In this embodiment, the auxiliary loads 117 include headlights 117a, wiper units 117b, power window units 117c, and meters 117d. The auxiliary loads 117 may include hardware for wirelessly operating the vehicle door locks, hardware related to a vehicle anti-theft system, hardware for monitoring the vehicle's surroundings such as a drive recorder, and hardware for connecting to a network such as a mobile phone network. If the vehicle is equipped with an engine, the normal load group 11 may include a starter motor for starting the engine.

[0015] The backup load group 21 includes loads that perform functions related to the vehicle's driving operation, stopping operation, or driving control. The backup load group 21 includes loads that perform functions related to the execution of a Minimal Risk Maneuver (MRM), which is the minimum driving operation, stopping operation, and driving control required to safely move the vehicle to the shoulder of the road and stop it even if an abnormality occurs in the power supply system 100. The backup load group 21 includes at least one of auxiliary loads used for vehicle driving control such as an ECU, auxiliary loads used for vehicle braking such as an automatic braking device, auxiliary loads used for vehicle steering such as an automatic steering device, and auxiliary loads used for acquiring information about the vehicle's external environment such as a LiDAR or an imaging device.

[0016] In this embodiment, the backup load group 21 includes an ECU 211 used to control the operation of the vehicle, an automatic brake control device 212 that controls the braking device used to brake the vehicle, an automatic steering control device 213 that controls the steering device used to steer the vehicle, and an external environment information processing device 214 that processes input information from a LiDAR or an imaging device used to acquire external environment information for the vehicle.

[0017] Some of the loads included in the backup load group 21 have some overlapping functions with the normal load group 11. In this embodiment, the ECU 211 of the backup load group 21 has an overlapping function with the ECU 111 of the normal load group 11, the automatic brake control device 212 of the backup load group 21 has an overlapping function with the automatic brake control device 112 of the normal load group 11, the automatic steering control device 213 of the backup load group 21 has an overlapping function with the automatic steering control device 113 of the normal load group 11, and the external information processing device 214 of the backup load group 21 has an overlapping function with the external information processing device 114 of the normal load group 11.

[0018] In this way, by making the backup load group 21 partially overlap in function with the normal load group 11, it is possible to multiplex and make redundant the functions related to the execution of MRM, which is the minimum driving operation, stopping operation, and driving control required to safely move the vehicle to the shoulder of the road and stop it, even if an abnormality occurs in the power supply system 100. Therefore, even if an abnormality occurs in the power supply system 100 and one of the loads in the normal load group 11 or the backup load group 21 stops functioning, the MRM can be executed by the other load, thereby ensuring traffic safety.

[0019] The normal load group 11 and the backup load group 21 each include high-voltage loads that operate using a voltage of a second level L2 (e.g., 48 V) lower than the first level L1 as a power supply voltage, and low-voltage loads that operate using a voltage of a third level L3 (e.g., 12 V) lower than the second level L2 as a power supply voltage.

[0020] The power supply system 100 includes a first DC / DC converter 41 and a second DC / DC converter 42 connected in parallel to a high-voltage power supply 30, an auxiliary power supply 12 capable of outputting a voltage of a second level L2, a first switch 51, a second switch 52, a third switch 53, a fourth switch 54, and a fifth switch 55. The auxiliary power supply 12 is configured to include a secondary battery such as a lithium-ion battery or an all-solid-state battery. The auxiliary power supply 12 may also be configured with a capacitor.

[0021] The first DC / DC converter 41 and the second DC / DC converter 42 are configured to be able to convert a voltage of the first level L1 into a voltage of the second level L2 and a voltage of the third level L3, respectively, and to convert a voltage of the second level L2 into a voltage of the third level L3. The first DC / DC converter 41 and the second DC / DC converter 42 may also be configured to be able to convert a voltage of the second level L2 into a voltage of the first level L1.

[0022] An input / output terminal 41A for a voltage of the first level L1 in the first DC / DC converter 41 is connected to one end of a fifth switch 55. The other end of the fifth switch 55 is connected to the high-voltage power supply 30.

[0023] One end of a high-voltage power supply line 10H is connected to an input / output terminal 41B for a voltage of the second level L2 in the first DC / DC converter 41. A high-voltage load included in the normal load group 11 is connected in parallel to the other end of the high-voltage power supply line 10H.

[0024] A third switch 53 is provided on the high-voltage power supply line 10H between the input / output terminal 41B of the first DC / DC converter 41 and the normal load group 11. One end of the third switch 53 is connected to the input / output terminal 41B, and the other end of the third switch 53 is connected to the high-voltage load of the normal load group 11. An auxiliary power supply 12 is connected to the high-voltage power supply line 10H between the other end of the third switch 53 and the high-voltage load of the normal load group 11.

[0025] One end of a low-voltage power supply line 10L is connected to an input / output terminal 41C for a voltage of the third level L3 in the first DC / DC converter 41. A low-voltage load included in the normal load group 11 is connected in parallel to the other end of the low-voltage power supply line 10L.

[0026] An input / output terminal 42A for a voltage of the first level L1 in the second DC / DC converter 42 is connected to one end of the fifth switch 55. One end of a high-voltage power supply line 20H is connected to an input / output terminal 42B for a voltage of the second level L2 in the second DC / DC converter 42. A high-voltage load included in the backup load group 21 is connected in parallel to the other end of the high-voltage power supply line 20H.

[0027] A fourth switch 54 is provided on the high-voltage power supply line 20H between the input / output terminal 42B of the second DC / DC converter 42 and the backup load group 21. One end of the fourth switch 54 is connected to the input / output terminal 42B, and the other end of the fourth switch 54 is connected to the high-voltage load of the backup load group 21.

[0028] One end of the low-voltage power supply line 20L is connected to an input / output terminal 42C for a voltage of the third level L3 in the second DC / DC converter 42. A low-voltage load included in the backup load group 21 is connected in parallel to the other end of the low-voltage power supply line 20L.

[0029] The first switch 51 has one end connected to the high-voltage power supply line 10H and the other end connected to the high-voltage power supply line 20H, and is configured to be able to switch between electrical connection and disconnection between the high-voltage power supply line 10H and the high-voltage power supply line 20H.

[0030] The second switch 52 has one end connected to the low-voltage power supply line 10L and the other end connected to the low-voltage power supply line 20L, and is configured to be able to switch between electrical connection and disconnection between the low-voltage power supply line 10L and the low-voltage power supply line 20L.

[0031] The first switch 51 to the fifth switch 55 are each configured with a switching element such as a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), or a diode having a switching function. Each of the first switch 51 to the fifth switch 55 is configured to receive a power supply voltage from, for example, the auxiliary power supply 12. In this embodiment, the switches are described as having one end and the other end electrically connected when in an on state (connected state) and electrically disconnected when in an off state (disconnected state).

[0032] The first DC / DC converter 41, the second DC / DC converter 42, and the first switch 51 to the fifth switch 55 are controlled, for example, by the ECU 111 of the normal load group 11 and the ECU 211 of the backup load group 21. The first DC / DC converter 41, the second DC / DC converter 42, and the first switch 51 to the fifth switch 55 may be controlled by a control device other than the ECU 111 of the normal load group 11 and the ECU 211 of the backup load group 21.

[0033] 2 is a schematic diagram showing the internal configuration of the first DC / DC converter 41. The internal configuration of the second DC / DC converter 42 is the same as that of the first DC / DC converter 41, and therefore some explanation will be omitted.

[0034] 2, the first DC / DC converter 41 is a power conversion circuit equipped with an insulating multi-port transformer 410. The multi-port transformer 410 is a transformer equipped with three or more input / output terminals (three in the illustrated example). The multi-port transformer 410 has three or more coils (three coils, coil 411, coil 412, and coil 413 in the illustrated example) that are magnetically coupled to each other.

[0035] The first DC / DC converter 41 includes a first switching circuit unit 411A connected to the coil 411, a second switching circuit unit 412A connected to the coil 412, and a third switching circuit unit 413A connected to the coil 413.

[0036] The first switching circuit section 411A is connected to the input / output terminal 41A (input / output terminal 42A in the case of the second DC / DC converter 42) shown in Fig. 1. The second switching circuit section 412A is connected to the input / output terminal 41B (input / output terminal 42B in the case of the second DC / DC converter 42) shown in Fig. 1. The third switching circuit section 413A is connected to the input / output terminal 41C (input / output terminal 42C in the case of the second DC / DC converter 42) shown in Fig. 1.

[0037] The first switching circuit unit 411A, the second switching circuit unit 412A, and the third switching circuit unit 413A may each include a switching element such as a MOSFET, an IGBT, or a diode having a switching function. The first switching circuit unit 411A, the second switching circuit unit 412A, and the third switching circuit unit 413A may each include, for example, a bridge circuit or a half-bridge circuit. The first switching circuit unit 411A, the second switching circuit unit 412A, and the third switching circuit unit 413A may each include a bridge circuit and the other may include a half-bridge circuit.

[0038] The first DC / DC converter 41 and the second DC / DC converter 42 can operate in a first mode, a second mode, and a third mode, respectively. Below, we will explain each mode of the first DC / DC converter 41. The modes of the second DC / DC converter 42 are the same as those of the first DC / DC converter 41, so explanations will be omitted.

[0039] Fig. 3 is a diagram showing the flow of power in the first DC / DC converter 41 when operating in the first mode. As shown in Fig. 3, in the first mode, the first DC / DC converter 41 converts a voltage of the second level L2 input to the input / output terminal 41B into a voltage of the third level L3 using the coil 412 and the second switching circuit section 412A, and the coil 413 and the third switching circuit section 413A, and outputs the converted voltage from the input / output terminal 41C.

[0040] Fig. 4 is a diagram showing the flow of power in the first DC / DC converter 41 when operating in the second mode. As shown in Fig. 4, in the second mode, the first DC / DC converter 41 converts a voltage of a first level L1 input to the input / output terminal 41A to a voltage of a second level L2 using the coil 411 and the first switching circuit unit 411A, and the coil 412 and the second switching circuit unit 412A, and outputs the voltage from the input / output terminal 41B. Furthermore, the first DC / DC converter 41 converts a voltage of the first level L1 input to the input / output terminal 41A to a voltage of a third level L3 using the coil 411 and the first switching circuit unit 411A, and the coil 413 and the third switching circuit unit 413A, and outputs the voltage from the input / output terminal 41C.

[0041] Fig. 5 is a diagram showing the flow of power in the first DC / DC converter 41 when operating in the third mode. As shown in Fig. 5, in the third mode, the first DC / DC converter 41 converts a voltage of the second level L2 input to the input / output terminal 41B to a voltage of the first level L1 using the coil 411 and the first switching circuit unit 411A, and the coil 412 and the second switching circuit unit 412A, and outputs the voltage from the input / output terminal 41A. Furthermore, the first DC / DC converter 41 converts a voltage of the second level L2 input to the input / output terminal 41B to a voltage of the third level L3 using the coil 412 and the second switching circuit unit 412A, and the coil 413 and the third switching circuit unit 413A, and outputs the voltage from the input / output terminal 41C.

[0042] 6 is a diagram illustrating the operation of the power supply system 100 when the vehicle is in a startup state. The startup state of the vehicle refers to a state in which, for example, power is supplied to each load in the normal load group 11 and each load in the backup load group 21 shown in the figure, and the vehicle can start running by operating the accelerator. The non-startup state of the vehicle refers to a state other than a state in which the vehicle can start running by operating the accelerator, and refers to a state in which the minimum necessary power is supplied to the normal load group 11 and the backup load group 21. When a startup operation is performed from the non-startup state, the vehicle performs a predetermined startup process, and when this startup process is completed, the vehicle transitions to the startup state.

[0043] As shown in Fig. 6, when the vehicle is in a start-up state, the first switch 51 and the second switch 52 are controlled to an OFF state, and the third switch 53, the fourth switch 54, and the fifth switch 55 are controlled to an ON state. Furthermore, the first DC / DC converter 41 and the second DC / DC converter 42 each operate in the second mode (see Fig. 4).

[0044] When the vehicle is in a startup state, a voltage of a first level L1 from the high-voltage power supply 30 is stepped down by the first DC / DC converter 41 and the second DC / DC converter 42 and converted into a voltage of a second level L2 and a voltage of a third level L3. The voltage of the second level L2 converted by the first DC / DC converter 41 is supplied to the high-voltage loads of the normal load group 11 via the high-voltage power supply line 10H, and the voltage of the third level L3 converted by the first DC / DC converter 41 is supplied to the low-voltage loads of the normal load group 11 via the low-voltage power supply line 10L. The voltage of the second level L2 converted by the second DC / DC converter 42 is supplied to the high-voltage loads of the backup load group 21 via the high-voltage power supply line 20H, and the voltage of the third level L3 converted by the second DC / DC converter 42 is supplied to the low-voltage loads of the backup load group 21 via the low-voltage power supply line 20L.

[0045] In addition, when the power supplied to the high-voltage power supply line 10H is insufficient for the power to be supplied to the high-voltage loads of the normal load group 11, power from the auxiliary power supply 12 is supplied to the high-voltage loads via the high-voltage power supply line 10H.

[0046] In this way, when the vehicle is in an activated state, power is supplied to the normal load group 11 and the backup load group 21, so even if the power supply to one of the normal load group 11 and the backup load group 21 is interrupted, the power supply to the other can be continued. Therefore, even if the vehicle is traveling in autonomous driving mode, the vehicle can be stopped safely.

[0047] Fig. 7 is a diagram illustrating the flow of power when an abnormality occurs in the second DC / DC converter 42 in the startup state shown in Fig. 6, making it impossible for the second DC / DC converter 42 to perform appropriate power conversion. In this case, the second DC / DC converter 42 is stopped, and the fourth switch 54 is controlled to the off state. Note that the fourth switch 54 may remain in the on state. Meanwhile, the first DC / DC converter 41 continues to operate in the second mode, as in Fig. 6. Therefore, the supply of the voltage of the second level L2 and the voltage of the third level L3 to the normal load group 11 continues.

[0048] Fig. 8 is a diagram illustrating the flow of power when an abnormality occurs in the first DC / DC converter 41 in the startup state shown in Fig. 6, making it impossible for the first DC / DC converter 41 to perform appropriate power conversion. In this case, the first DC / DC converter 41 is stopped, and the third switch 53 is controlled to the off state. Note that the third switch 53 may remain in the on state. Meanwhile, the second DC / DC converter 42 continues to operate in the second mode, as in Fig. 6. Therefore, the supply of the voltage at the second level L2 and the voltage at the third level L3 to the backup load group 21 continues.

[0049] Fig. 9 is a diagram illustrating the flow of power when an abnormality occurs in the high-voltage power supply 30 in the startup state shown in Fig. 6, making it impossible to supply appropriate power from the high-voltage power supply 30. In this case, the fifth switch 55 is controlled to the off state. Also, the second DC / DC converter 42 is stopped. Meanwhile, the first DC / DC converter 41 switches from the second mode to the first mode (see Fig. 3).

[0050] When the first DC / DC converter 41 operates in the first mode, a voltage of the second level L2 is supplied from the auxiliary power supply 12 to the high-voltage loads of the normal load group 11 via the high-voltage power supply line 10H. In addition, a voltage of the second level L2 is supplied from the auxiliary power supply 12 to the first DC / DC converter 41, and this voltage is converted to a voltage of the third level L3 by the first DC / DC converter 41. The voltage of the third level L3 output from the first DC / DC converter 41 is supplied to the low-voltage loads of the normal load group 11 via the low-voltage power supply line 10L.

[0051] Fig. 10 is a diagram illustrating another example of the flow of power when an abnormality occurs in the high-voltage power supply 30 in the startup state shown in Fig. 6 and the high-voltage power supply 30 is unable to supply appropriate power. In the example of Fig. 10, the fifth switch 55 and the third switch 53 are controlled to the off state, and the first switch 51 is controlled to the on state. Also, the first DC / DC converter 41 is stopped. Note that the third switch 53 may be controlled to the on state. Meanwhile, the second DC / DC converter 42 switches from the second mode to the first mode.

[0052] When the second DC / DC converter 42 operates in the first mode, a voltage of the second level L2 is supplied from the auxiliary power supply 12 to the high-voltage loads of the backup load group 21 via the high-voltage power supply line 10H, the first switch 51, and the high-voltage power supply line 20H. The voltage of the second level L2 supplied from the auxiliary power supply 12 to the high-voltage power supply line 20H is input to the second DC / DC converter 42, where it is converted to a voltage of the third level L3. The voltage of the third level L3 output from the second DC / DC converter 42 is then supplied to the low-voltage loads of the backup load group 21 via the low-voltage power supply line 20L.

[0053] 9 and 10, according to the power supply system 100, even if an abnormality occurs in the high-voltage power supply 30, it is possible to continue supplying power to either the normal load group 11 or the backup load group 21 by using the auxiliary power supply 12. Because only one auxiliary power supply 12 is required, the manufacturing cost of the power supply system 100 can be reduced.

[0054] Fig. 11 is a diagram illustrating the flow of power when a short circuit occurs in the second DC / DC converter 42 in the startup state shown in Fig. 6. In this case, the fourth switch 54 and the fifth switch 55 are controlled to the off state. Also, the first DC / DC converter 41 switches from the second mode to the first mode.

[0055] When the first DC / DC converter 41 operates in the first mode, a voltage of the second level L2 is supplied from the auxiliary power supply 12 via the high-voltage power supply line 10H to the high-voltage loads of the normal load group 11 and to the first DC / DC converter 41. The voltage of the second level L2 input to the first DC / DC converter 41 is converted to a voltage of the third level L3. This voltage of the third level L3 is supplied to the low-voltage loads of the normal load group 11 via the low-voltage power supply line 10L.

[0056] Fig. 12 is a diagram illustrating the flow of power when a short circuit occurs in the first DC / DC converter 41 in the startup state shown in Fig. 6. In this case, the third switch 53 and the fifth switch 55 are controlled to the off state, and the first switch 51 is controlled to the on state. Then, the second DC / DC converter 42 switches from the second mode to the first mode.

[0057] When the second DC / DC converter 42 operates in the first mode, a voltage of the second level L2 is supplied from the auxiliary power supply 12 to the high-voltage loads of the backup load group 21 and the second DC / DC converter 42 via the high-voltage power supply line 10H, the first switch 51, and the high-voltage power supply line 20H. The voltage of the second level L2 input to the second DC / DC converter 42 is converted to a voltage of a third level L3. This voltage of the third level L3 is supplied to the low-voltage loads of the backup load group 21 via the low-voltage power supply line 20L.

[0058] 11 and 12, according to the power supply system 100, even if a short circuit occurs in the first DC / DC converter 41 or the second DC / DC converter 42, it is possible to continue supplying power to either the normal load group 11 or the backup load group 21 by using the auxiliary power supply 12. Because only one auxiliary power supply 12 is required, the manufacturing cost of the power supply system 100 can be reduced.

[0059] 9 to 12, when the system transitions from a state in which power is being supplied to the normal load group 11 and the backup load group 21 using the high-voltage power supply 30 to a state in which the high-voltage power supply 30 cannot be used, it becomes necessary to switch from the second mode to the first mode in the first DC / DC converter 41 or the second DC / DC converter 42. If this switching takes time, it is effective to connect an auxiliary power supply 12A to the low-voltage power supply line 10L, as shown in FIGS. 9 to 12. The auxiliary power supply 12A is capable of outputting a voltage of the third level L3 and can be manufactured more inexpensively than the auxiliary power supply 12.

[0060] 9 and 11, during the period until the first DC / DC converter 41 switches from the second mode to the first mode, a voltage at the second level L2 can be supplied from the auxiliary power supply 12A to the low-voltage loads of the normal load group 11. Therefore, if it takes a long time for the first DC / DC converter 41 to switch modes, it is possible to avoid a momentary interruption in the power supply to the low-voltage loads of the normal load group 11.

[0061] 10 and 12, the second switch 52 is controlled to the on state only during the period until the second DC / DC converter 42 switches from the second mode to the first mode, thereby enabling a voltage of the second level L2 to be supplied from the auxiliary power supply 12A to the low-voltage loads of the backup load group 21. Therefore, if it takes time for the second DC / DC converter 42 to switch modes, it is possible to avoid a momentary interruption in the power to the low-voltage loads of the backup load group 21.

[0062] As described above, providing auxiliary power supply 12A is effective. Because the power of auxiliary power supply 12A is only used temporarily, auxiliary power supply 12A can be constructed inexpensively. For this reason, even when auxiliary power supply 12A is added, the manufacturing cost of power supply system 100 can be reduced compared to, for example, when two auxiliary power supplies 12 are provided.

[0063] 13 is a diagram illustrating the flow of power when the vehicle is in a non-started state. When the vehicle is in a non-started state, the first switch 51, the second switch 52, and the third switch 53 are controlled to an ON state, and the fourth switch 54 and the fifth switch 55 are controlled to an OFF state. In addition, the second DC / DC converter 42 is stopped. The first DC / DC converter 41 operates in the first mode.

[0064] When the first DC / DC converter 41 operates in the first mode, a voltage of the second level L2 is supplied from the auxiliary power supply 12 to the high-voltage loads of the normal load group 11 and to the first DC / DC converter 41 via the high-voltage power supply line 10H. The voltage of the second level L2 input to the first DC / DC converter 41 is converted to a voltage of the third level L3. This voltage of the third level L3 is supplied to the low-voltage loads of the normal load group 11 via the low-voltage power supply line 10L, and is also supplied to the low-voltage loads of the backup load group 21 via the low-voltage power supply line 10L, the second switch 52, and the low-voltage power supply line 20L. Furthermore, a voltage of the second level L2 is supplied from the auxiliary power supply 12 to the high-voltage loads of the backup load group 21 via the high-voltage power supply line 10H, the first switch 51, and the high-voltage power supply line 20H.

[0065] In this way, when the vehicle is not started, the voltage required to be supplied to the normal load group 11 and the backup load group 21 can be supplied only by the auxiliary power supply 12, thereby reducing the number of power supplies. Furthermore, even when the second DC / DC converter 42 is stopped, the backup load group 21 can be supplied with a voltage of the second level L2 and a voltage of the third level L3, so that the voltage can be efficiently supplied to the backup load group 21.

[0066] When the vehicle is in a non-started state, the first DC / DC converter 41 preferably operates by switching between a first mode and a second mode. Fig. 14 is a diagram illustrating the flow of power when the mode of the first DC / DC converter 41 switches from the state shown in Fig. 13 to the second mode. In this case, the fifth switch 55 is controlled to the on state. Since the first DC / DC converter 41 operates in the second mode, a voltage of a second level L2 and a voltage of a third level L3 are generated from the first level L1 supplied to the first DC / DC converter 41 from the high-voltage power supply 30.

[0067] The voltage of the second level L2 output from the first DC / DC converter 41 is supplied to the high-voltage loads of the normal load group 11 via the high-voltage power supply line 10H, and is supplied to the high-voltage loads of the backup load group 21 via the high-voltage power supply line 10H, the first switch 51, and the high-voltage power supply line 20H. In addition, the auxiliary power supply 12 is charged by the voltage of the second level L2 output from the first DC / DC converter 41.

[0068] The voltage of the third level L3 output from the first DC / DC converter 41 is supplied to the low-voltage loads of the normal load group 11 via the low-voltage power supply line 10L, and is supplied to the low-voltage loads of the backup load group 21 via the low-voltage power supply line 10L, the second switch 52, and the low-voltage power supply line 20L.

[0069] When the auxiliary power supply 12 is sufficiently charged, the first DC / DC converter 41 switches from the second mode to the first mode, the fifth switch 55 is controlled to the off state, and the state returns to that shown in Fig. 13. Then, the charged auxiliary power supply 12 supplies power to the normal load group 11 and the backup load group 21. Charging the auxiliary power supply 12 in this manner ensures that the auxiliary power supply 12 has sufficient power to be used in the states shown in Figs. 9 to 13.

[0070] Fig. 15 is a diagram illustrating the flow of power when the vehicle transitions from a non-started state to a started state. When a start-up operation is performed in the state shown in Fig. 13, the fifth switch 55 is controlled to the on state, and the first DC / DC converter 41 switches from the first mode to the third mode (see Fig. 5). When the first DC / DC converter 41 switches to the third mode, the voltage of the second level L2 from the auxiliary power supply 12 is boosted and output from the first DC / DC converter 41, and charged into the capacitor of the high-voltage power supply 30. The rest of the power flow is the same as that described in Fig. 13. When charging of the capacitor of the high-voltage power supply 30 is completed and the subsequent start-up process is completed, the power supply system 100 enters the state shown in Fig. 6 (started state).

[0071] As described above, when the vehicle transitions from a non-started state to a started state, the capacitor of the high-voltage power supply 30 can be charged by the power of the auxiliary power supply 12, thereby shortening the time required to complete the start-up process and enabling fast start-up. Also, even while the capacitor of the high-voltage power supply 30 is being charged, the voltage of the second level L2 and the voltage of the third level L3 can be supplied to the normal load group 11 and the backup load group 21, as in the state shown in Fig. 13. This prevents interruption of the supply of the minimum necessary power to the loads.

[0072] Although one embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above embodiment may be combined in any manner without departing from the spirit of the invention.

[0073] This specification describes at least the following: In parentheses, components corresponding to those in the above-described embodiments are shown as examples, but the present invention is not limited to these.

[0074] (1) The power supply is equipped with a first power conversion circuit (first DC / DC converter 41) and a second power conversion circuit (second DC / DC converter 42) connected in parallel to a first power supply (high-voltage power supply 30) mounted on a vehicle and capable of outputting a voltage of a first level (first level L1: 400V), the first power conversion circuit and the second power conversion circuit are capable of converting the first level voltage into a second level voltage (second level L2: 48V) and a third level voltage (third level L3: 12V), respectively, and converting the second level voltage into the third level voltage; the second level voltage and the third level voltage output from the first power conversion circuit are configured to be able to be supplied to a first load (normal load group 11) of the vehicle, the second level voltage and the third level voltage output from the second power conversion circuit are configured to be able to be supplied to a second load (backup load group 21) of the vehicle, a first switch (first switch 51) that is a power supply line to which the second level voltage is supplied and that can switch between connection and disconnection between a first power supply line (high-voltage power supply line 10H) that connects the first power conversion circuit and the first load and a second power supply line (high-voltage power supply line 20H) that connects the second power conversion circuit and the second load; a second switch (second switch 52) that is capable of switching between connection and disconnection between a third power supply line (low-voltage power supply line 10L) that connects the first power conversion circuit and the first load and a fourth power supply line (low-voltage power supply line 20L) that connects the second power conversion circuit and the second load, the third power supply line being a power supply line to which the third level voltage is supplied; a second power supply (auxiliary power supply 12) connected to the first power supply line and capable of outputting the second level voltage, In the vehicle's non-start state (FIG. 13), the first power conversion circuit operates in a first mode to convert the second level voltage supplied from the second power supply into the third level voltage; the first switch and the second switch are controlled to a connected state, the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit; the second level voltage output from the second power supply is supplied to the second load via the first switch; the third level voltage output from the first power conversion circuit is supplied to the first load; The third-level voltage output from the first power conversion circuit is supplied to the second load via the second switch.

[0075] According to (1), the two levels of voltage required to be supplied to the first load and the second load when the vehicle is not running can be supplied only by the second power supply, thereby reducing the number of power supplies. Furthermore, even when the second power conversion circuit is stopped, the second load can be supplied with the second level voltage and the third level voltage, thereby enabling efficient voltage supply to the loads.

[0076] (2) The power supply system according to (1), When the vehicle is in a non-start state, the second power conversion circuit is stopped.

[0077] According to (2), it is possible to reduce power consumption when the vehicle is not running.

[0078] (3) The power supply system according to (1) or (2), In a non-start state of the vehicle, the first power conversion circuit switches between the first mode and a second mode in which the first level voltage output from the first power supply is converted into the second level voltage and the third level voltage; When the first power conversion circuit operates in the second mode (FIG. 14), the second level voltage output from the first power conversion circuit is supplied to the first load; the second level voltage output from the first power conversion circuit is supplied to the second load via the first switch; the second power supply is charged by the second level voltage output from the first power conversion circuit; the third level voltage output from the first power conversion circuit is supplied to the first load; the third-level voltage output from the first power conversion circuit is supplied to the second load via the second switch.

[0079] According to (3), when the first power conversion circuit operates in the second mode, the second power source can be charged by the first power source, and the voltage of the first power source can be used to supply the first load and the second load with a second level voltage and a third level voltage. Since the second power source can be charged even when the vehicle is not started, it is possible to stably supply voltage to the first load and the second load when the vehicle is not started.

[0080] (4) The power supply system according to any one of (1) to (3), When the vehicle transitions from a non-startup state to an activation state (FIG. 15), the first power conversion circuit operates in a third mode to convert the second level voltage output from the second power supply into the first level voltage and the third level voltage; When the first power conversion circuit operates in the third mode, the third level voltage output from the first power conversion circuit is supplied to the first load; the third-level voltage output from the first power conversion circuit is supplied to the second load via the second switch; the second level voltage output from the second power supply is supplied to the first load; the second level voltage output from the second power supply is supplied to the second load via the first switch; a power supply system in which the voltage of the first level output from the first power conversion circuit is supplied to the first power supply;

[0081] According to (4), when the vehicle transitions from a non-started state to a started state, the capacitor of the first power supply can be charged from the second power supply, thereby shortening the time until startup is complete. Also, even during this transition period, the voltage of the second power supply can be used to supply the second level voltage and the third level voltage to the first load and the second load.

[0082] (5) A power supply system according to any one of (1) to (4), When the vehicle is in a start state and the first power conversion circuit is short-circuited (FIG. 12), the first switch is controlled to a connected state; the second level voltage output from the second power supply is supplied to the second load and the second power conversion circuit via the first switch; the second power conversion circuit operates in the first mode; the third level voltage output from the second power conversion circuit is supplied to the second load.

[0083] According to (5), even if the first power conversion circuit is short-circuited and the second power conversion circuit is unable to generate the second level and third level voltages from the voltage of the first power source, the second level and third level voltages can be supplied to the second load from the voltage of the second power source via the first switch and the second power conversion circuit, thereby supplying the necessary voltage to the second load and maintaining the functionality of the vehicle.

[0084] (6) The power supply system according to any one of (1) to (5), When the vehicle is in a start state and the second power conversion circuit is short-circuited (FIG. 11), the first switch and the second switch are controlled to be in a cut-off state; the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit; the first power conversion circuit operates in the first mode; the third level voltage output from the first power conversion circuit is supplied to the first load.

[0085] According to (6), even if the second power conversion circuit is short-circuited and the first power conversion circuit is unable to generate second-level and third-level voltages from the voltage of the first power source, the second power source can supply the second-level voltage to the first load, and the second power source can supply the third-level voltage to the first load via the first power conversion circuit. This makes it possible to supply the necessary voltage to the first load and maintain the functionality of the vehicle.

[0086] (7) The power supply system according to any one of (1) to (6), When the vehicle is in a start-up state and the first power source is unable to supply voltage to the first power conversion circuit and the second power conversion circuit (FIG. 9), the first switch and the second switch are controlled to be in a cut-off state; the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit; the first power conversion circuit operates in the first mode; the third level voltage output from the first power conversion circuit is supplied to the first load.

[0087] According to (7), even if the first power source is unavailable, two levels of voltage can be supplied to the first load, so the necessary voltage can be supplied to the first load to maintain the functionality of the vehicle.

[0088] (8) The power supply system according to any one of (1) to (7), When the vehicle is in a start-up state and the first power source is unable to supply voltage to the first power conversion circuit and the second power conversion circuit (FIG. 10), the first switch is controlled to a connected state; the second level voltage output from the second power supply is supplied to the second load and the second power conversion circuit via the first switch; the second power conversion circuit operates in the first mode; the third level voltage output from the second power conversion circuit is supplied to the second load.

[0089] According to (8), even if the first power source is unavailable, two levels of voltage can be supplied to the second load from the voltage of the second power source via the first switch and the second power conversion circuit, thereby supplying the necessary voltage to the second load and maintaining the functionality of the vehicle. [Explanation of symbols]

[0090] 10H, 20H high voltage power line 10L, 20L low voltage power line 11 Normal load group 12,12A auxiliary power supply 21 Backup Load Group 30 High voltage power supply 41 First DC / DC converter 41A,41B,41C,42A,42B,42C input / output terminal 42 Second DC / DC converter 51 First Switch 52 Second Switch 53 Third Switch 54 4th Switch 55 5th Switch 100 Power System 111,211 ECU 112,212 Automatic brake control device 113,213 Automatic steering control device 114,214 External information processing device 117 Auxiliary Load 117a Headlight 117b Wiper device 117c Power window device 117d Instruments 410 Multi-port transformer 411,412,413 Coil 411A First switching circuit section 412A Second switching circuit section 413A Third switching circuit section L1 First level L2 Second Level L3 Third level

Claims

1. a first power conversion circuit and a second power conversion circuit connected in parallel to a first power source mounted on a vehicle and capable of outputting a voltage of a first level; the first power conversion circuit and the second power conversion circuit are capable of converting the first level voltage to a second level voltage and a third level voltage, and converting the second level voltage to the third level voltage, respectively; the second level voltage and the third level voltage output from the first power conversion circuit are configured to be able to be supplied to a first load of the vehicle, the second level voltage and the third level voltage output from the second power conversion circuit are configured to be able to be supplied to a second load of the vehicle, a first switch configured to switch between connection and disconnection of a first power supply line connecting the first power conversion circuit and the first load and a second power supply line connecting the second power conversion circuit and the second load, the first power supply line being a power supply line to which the second level voltage is supplied; a second switch capable of switching between connection and disconnection between a third power supply line connecting the first power conversion circuit and the first load and a fourth power supply line connecting the second power conversion circuit and the second load, the third power supply line being a power supply line to which the third level voltage is supplied; a second power supply connected to the first power supply line and capable of outputting a voltage of the second level; In a non-start state of the vehicle, the first power conversion circuit operates in a first mode to convert the second level voltage supplied from the second power supply into the third level voltage; the first switch and the second switch are controlled to a connected state, the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit; the second level voltage output from the second power supply is supplied to the second load via the first switch; the third level voltage output from the first power conversion circuit is supplied to the first load; The third level voltage output from the first power conversion circuit is supplied to the second load via the second switch.

2. 2. The power supply system of claim 1, When the vehicle is in a non-start state, the second power conversion circuit is stopped.

3. 3. The power supply system according to claim 2, In a non-start state of the vehicle, the first power conversion circuit switches between the first mode and a second mode in which the first level voltage output from the first power supply is converted into the second level voltage and the third level voltage; When the first power conversion circuit operates in the second mode, the second level voltage output from the first power conversion circuit is supplied to the first load; the second level voltage output from the first power conversion circuit is supplied to the second load via the first switch; the second power supply is charged by the second level voltage output from the first power conversion circuit; the third level voltage output from the first power conversion circuit is supplied to the first load; The third level voltage output from the first power conversion circuit is supplied to the second load via the second switch.

4. 4. The power supply system according to claim 3, When the vehicle transitions from a non-activated state to an activated state, the first power conversion circuit operates in a third mode to convert the second level voltage output from the second power supply into the first level voltage and the third level voltage; When the first power conversion circuit operates in the third mode, the third level voltage output from the first power conversion circuit is supplied to the first load; the third level voltage output from the first power conversion circuit is supplied to the second load via the second switch; the second level voltage output from the second power supply is supplied to the first load; the second level voltage output from the second power supply is supplied to the second load via the first switch; The first level voltage output from the first power conversion circuit is supplied to the first power supply.

5. 5. The power supply system according to claim 2, When the vehicle is in a start-up state and the first power conversion circuit is short-circuited, the first switch is controlled to a connected state; the second level voltage output from the second power supply is supplied to the second load and the second power conversion circuit via the first switch; the second power conversion circuit operates in the first mode; The third level voltage output from the second power conversion circuit is supplied to the second load.

6. 5. The power supply system according to claim 2, When the vehicle is in a start-up state and the second power conversion circuit is short-circuited, the first switch and the second switch are controlled to be in an interrupted state; the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit; the first power conversion circuit operates in the first mode; The third level voltage output from the first power conversion circuit is supplied to the first load.

7. 5. The power supply system according to claim 2, When the vehicle is in a start-up state and it becomes impossible to supply voltage from the first power source to the first power conversion circuit and the second power conversion circuit, the first switch and the second switch are controlled to be in an interrupted state; the second level voltage output from the second power supply is supplied to the first load and the first power conversion circuit; the first power conversion circuit operates in the first mode; The third level voltage output from the first power conversion circuit is supplied to the first load.

8. 5. The power supply system according to claim 2, When the vehicle is in a start-up state and it becomes impossible to supply voltage from the first power source to the first power conversion circuit and the second power conversion circuit, the first switch is controlled to a connected state; the second level voltage output from the second power supply is supplied to the second load and the second power conversion circuit via the first switch; the second power conversion circuit operates in the first mode; The third level voltage output from the second power conversion circuit is supplied to the second load.

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