Redundantes Energieversorgungssystem

Abstract

Redundant power supply system (1, 2, 3, 4) in which a predetermined energy is supplied to a first battery (12) and a first load (13, 14) of a primary system via a first DC-DC converter (11), and the predetermined energy is supplied via a second DC-DC converter (21) to a second battery (22) and a second load (23) of a secondary system that is independent of the primary system, wherein the redundant power supply system (1, 2, 3, 4) comprises: a first switching element (S1) which is arranged between the second DC voltage converter (21) and the second battery (22), a first diode (D1) connected in parallel to the first switching element (S1) and configured to perform rectification in one direction from the second battery (22) to the second DC-DC converter (21), and a control section (121, 122, 123, 124) which is configured to switch off the first switching element (S1) when the second battery (22) is in a first state in which its stored energy quantity is equal to or greater than a predetermined first threshold, and to switch on the first switching element (S1) when the second battery (22) is in a state other than the first state, and a third DC voltage converter (134) through which the second battery (22) and the first battery (12) are connected to each other in order to be chargeable and dischargeable, wherein In the first state, in which the first switching element (S1) is switched off, the control section (124) causes the third DC voltage converter (134) to discharge some of the energy stored in the second battery (22) using the first battery (12), thereby determining a deterioration state of the second battery (22).

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to a redundant power supply system to be mounted on a vehicle. Description of the state of the art

[0002] DE 10 2016 200 091 A1 discloses a method for coupling a consumer in an on-board electrical system, which has a first on-board electrical system channel in which at least one opener is provided, and a second on-board electrical system channel in which at least one makeer is provided, wherein the at least one makeer and the at least one opener form a coupling element via which the consumer is coupled to one of the two on-board electrical system channels, wherein the coupling element is controlled with at least one common control signal, so that a coupling of the consumer to one of the two on-board electrical system channels is effected.

[0003] DE 10 2005 039 104 A1 discloses a vehicle electrical system for supplying energy to a hybrid vehicle, comprising a traction electrical system, a standard electrical system and at least one safety-relevant electrical consumer which is electrically connected to the standard electrical system, and further comprising a coupling element which electrically connects the consumer optionally to the traction electrical system and / or the standard electrical system.

[0004] EP 3 282 544 A1 discloses a secondary battery protection circuit in which a combination of a switching element and a diode is used for a charging circuit, wherein a fuse is further provided as a protection element.

[0005] EP 2 221 937 A2 discloses a charging circuit for a single battery using a combination of a switching element and a diode.

[0006] US 2016 / 0 301 224 A1 discloses a battery protection circuit comprising a battery, a fuse, a charging switch having a first body diode forward-biased in a discharge path direction, a discharging switch having a second body diode forward-biased in a charging path direction, a thermistor having one terminal connected between the charging switch and the discharging switch, and a control device that detects a voltage value at another terminal of the thermistor and controls the fuse, the charging switch, and the discharging switch.

[0007] US 2007 / 0 247 114 A1 discloses a power supply for a computer using combinations of a switching element and a diode.

[0008] DE 102 16 831 A1 discloses a charging control circuit for a battery pack comprising rechargeable battery elements arranged in respective parallel branches of a parallel circuit of battery voltage sources, wherein each parallel branch is assigned condition monitoring means for monitoring the battery condition during a charging process of the battery pack, and wherein in each parallel branch a respective switch controllable by the condition monitoring means is provided for interrupting or releasing the charging current flow through the parallel branch in accordance with the battery condition.

[0009] Patent Document 1 (JP 2008 - 199 763 A) discloses a power supply system that realizes a redundant configuration by being provided with a first system and a second system, wherein power is supplied from a high-voltage power supply to a first battery and a second battery via DC-DC converters, respectively.

[0010] In a power supply system with a redundant configuration, it is desired that deterioration of a battery of one of the systems be suppressed by managing, with high accuracy, the energy storage state of the battery when the battery is used as a backup power supply for an important load in automatic driving.

[0011] Methods for suppressing battery deterioration include a method for preventing battery overcharging. One possible way to prevent a battery from being overcharged in a fully charged state is, for example, to isolate the battery from a power supply line of a DC-DC converter. However, in this case, it becomes difficult to quickly supply power from the battery to the power supply line when backup power is needed for a critical load. SUMMARY OF THE INVENTION

[0012] The present invention has been made in view of the above-described problem, and an object of the present invention is to provide a redundant power supply system having a battery which can be prevented from overcharging and which can be caused to quickly function as a backup power supply for an important load when necessary.

[0013] This object is achieved by a redundant energy supply system as defined in claim 1.

[0014] To solve the problem described above, one embodiment of the present invention is a redundant power supply system in which a predetermined energy (power) is supplied to a first battery and a first load of a primary system via a first DC-DC converter, and the predetermined energy is supplied to a second battery and a second load of a secondary system that is independent of the primary system via a second DC-DC converter, the redundant power supply system comprising: a first switching element arranged between the second DC-DC converter and the second battery, a first diode connected in parallel to the first switching element and configured to perform rectification in a direction from the second battery to the second DC-DC converter, and a control section configured to turn off the first switching element,when the second battery is in a first state in which its stored energy amount is equal to or greater than a predetermined first threshold, and to turn on the first switching element when the second battery is in a state other than the first state.

[0015] In this redundant power supply system, on a path from the second DC-DC converter to the second battery, the first switching element and the first diode that performs rectification in the direction opposite to the path are provided. When the second battery is in the first state, the first switching element is turned off, forming only a discharge path extending through the first diode. Through this control, overcharging of the second battery can be prevented in a fully charged state where the stored energy amount thereof is equal to or greater than the first threshold, and the second battery can be promptly made to function as a backup power supply when necessary.

[0016] In addition, the redundant power supply system according to the above-described configuration further includes a third DC-DC converter through which the second battery and the first battery are connected to each other to be chargeable and dischargeable, wherein in the first state in which the first switching element is turned off, the control section causes the third DC-DC converter to discharge a part of energy stored in the second battery using the first battery, thereby determining a deterioration state of the second battery.

[0017] With the redundant power supply system according to this type, discharging can be performed using the first battery without being affected by the charging process performed on the second battery by the second DC-DC converter, whereby the deterioration state of the second battery can be determined more accurately.

[0018] Advantageous embodiments are specified in the dependent patent claims.

[0019] In addition, the redundant power supply system according to the embodiment may further include: a second switching element arranged between the second DC-DC converter and the second battery so as to be connected in series with the first switching element, and a second diode connected in parallel with the second switching element and configured to perform rectification in a direction from the second DC-DC converter to the second battery, wherein the control section turns off the second switching element when the second battery is in a second state in which its stored energy amount is equal to or less than a predetermined second threshold value that is less than the first threshold value, and turns on the second switching element when the second battery is in a state other than the second state.

[0020] In this redundant power supply system, the second switching element and the second diode that performs rectification in the direction of the path are provided on the path from the second DC-DC converter to the second battery. When the second battery is in the second state, the second switching element is turned off, so that only a charging path extending through the second diode can be formed. Through this control, excessive discharge (overdischarge) of the second battery, which has a stored energy amount reduced to be equal to or less than the second threshold, can be prevented.

[0021] The redundant power supply system according to the above-described configuration may further include an energy storage section and a third DC-DC converter through which the second battery and the energy storage section are connected to each other to be chargeable and dischargeable, wherein in the first state in which the first switching element is turned off, the control section causes the third DC-DC converter to discharge a part of energy stored in the second battery using the energy storage section, thereby determining a deterioration state of the second battery.

[0022] With the redundant power supply system according to this type, discharging can be performed using the energy storage section without being affected by a charging operation performed on the second battery by the second DC-DC converter, whereby the deterioration state of the second battery can be accurately determined.

[0023] An arrangement in which the first switching element and the first diode are connected in parallel and an arrangement in which the second switching element and the second diode are connected in parallel can each be implemented by a field effect transistor having a body diode formed between a source and a drain.

[0024] Accordingly, each switching element and each diode can be formed as a single semiconductor element.

[0025] The present invention can realize a redundant power supply system with a battery that can be prevented from overcharging and can be caused to quickly function as a backup power supply for an important load when necessary.

[0026] These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram illustrating a schematic configuration of a redundant power supply system according to a first unclaimed example, Fig. 2A and Fig. 2B are diagrams for explaining states of a battery protection circuit controlled by a control section according to Fig. 1 is controlled, Fig. 3 is a block diagram illustrating a schematic configuration of a redundant power supply system according to a second unclaimed example, Fig. 4A and Fig. 4B are diagrams for explaining states of the battery protection circuit controlled by a control section according to Fig. 3 is controlled, Fig. 5 is a block diagram illustrating a schematic configuration of a redundant power supply system according to a third unclaimed example, Fig. 6A, Fig. 6B and Fig. 6C are diagrams for explaining states of a battery protection circuit controlled by a control section according to Fig. 5 is controlled, Fig. 7 is a block diagram showing a schematic configuration of a redundant power supply system according to an embodiment, and Fig. Fig. 8 is a diagram for explaining a state of the battery protection circuit controlled by a control section according to Fig. 7 is controlled. DESCRIPTION OF UNCLAIMED EXAMPLES AND THE PREFERRED EMBODIMENT Overview

[0027] In a redundant power supply system according to the present invention, a protective relay is provided between a DC-DC converter and a battery serving as a backup power supply for automatic driving. The state of the protective relay is appropriately switched based on the energy storage state of the battery, so that the formation and separation of a charging path and a discharging path are controlled. Accordingly, overcharging or excessive discharging (overdischarging) of the battery can be prevented. First unclaimed example configuration

[0028] Fig. Fig. 1 is a block diagram showing a schematic configuration of a redundant power supply system 1 according to a first unclaimed example. The redundant power supply system 1 shown in Fig. 1 as an example, is composed of: a power supply device (a primary system) including a first DC-DC converter (DDC) 11, a first battery 12, a first automatic driving system (ADS) 13, and a vehicle load 14; a power supply device (a secondary system) including a second DC-DC converter (DDC) 21, a second battery 22, a second automatic driving system (ADS) 23, a battery protection circuit 111, and a control section 121; and a power supply section 50.

[0029] The redundant power supply system 1 is mounted, for example, on a vehicle capable of automatic driving by means of a device in the vehicle. In the redundant power supply system 1 mounted on the vehicle, during manual driving, the first battery 12 of the primary system is used to drive (drive) the vehicle. During automatic driving, not only the first battery 12 is used, but the second battery 22 of the second system can also be used as a backup power supply in the event that, for example, the first battery 12 fails (failover).

[0030] The power supply section 50 can supply power to the first DC-DC converter 11 of the primary system and the second DC-DC converter 21 of the secondary system, which are connected in parallel. The power supply section 50 can be implemented by a high-voltage battery (vehicle battery or the like), for example, a lithium-ion battery, configured to be chargeable / dischargeable.

[0031] The first DC-DC converter 11 is configured to convert power supplied from the power supply section 50 and output the power obtained through the conversion to the first battery 12, the first automatic driving system 13, and the vehicle load 14. Specifically, the first DC-DC converter 11 steps down high-voltage power supplied from the power supply section 50 to obtain low-voltage power and outputs the low-voltage power to the first battery 12, the first automatic driving system 13, and the vehicle load 14.

[0032] The first battery 12 is an energy storage element, such as a lead-acid battery, configured to be chargeable / dischargeable. The first battery 12 is configured to store (charge) energy output from the first DC-DC converter 11 and to output the energy stored by itself to the first automatic driving system 13 and the vehicle load 14.

[0033] The first automatic driving system 13 is a system including some loads arranged to be driven by the first battery 12 used as a power supply, among loads required for automatic driving of the vehicle. Examples of the loads required for automatic driving include an automatic driving ECU (Electronic Control Unit), an electronic braking system (EBS), and an electric power steering (EPS).

[0034] The vehicle load 14 is at least one device mounted on the vehicle that can be powered by energy output from the first DC-DC converter 11 and / or energy stored in the first battery 12. The vehicle load 14 is a different load than the loads required for automatic driving.

[0035] The second DC-DC converter 21 is configured to convert power supplied from the power supply section 50 and output the power obtained through the conversion to the second battery 22 and the second automatic driving system 23. Specifically, the second DC-DC converter 21 steps down high-voltage power supplied from the power supply section 50 to obtain low-voltage power and outputs the low-voltage power to the second battery 22 and the second automatic driving system 23.

[0036] The second battery 22 is an energy storage element, such as a lead-acid battery or a lithium-ion battery, configured to be chargeable / dischargeable. The second battery 22 is configured to store (charge) energy output from the second DC-DC converter 21 via the battery protection circuit 111, and to output energy stored by itself to the second automatic driving system 23 via the battery protection circuit 111. The second battery 22 functions as a backup power supply when, for example, the first battery 12 fails while the vehicle is undergoing automatic driving.

[0037] The second automatic driving system 23 is a system including some loads arranged to be driven by the second battery 22 used as a power supply, among the loads required for automatic driving of the vehicle. The loads included in the second automatic driving system 23 are important loads required for automatic driving and each have a function of causing the vehicle to safely perform emergency operation by supplying power from the secondary system in the event of an emergency, such as a case where power supply from the primary system fails.

[0038] The battery protection circuit 111 is a relay circuit arranged between the second DC-DC converter 21 and the second battery 22, and serves to prevent overcharging of the second battery 22. The term "overcharging" refers to a state in which the second battery 22 continues to be charged from a fully charged state in which the stored energy amount of the second battery 22 is equal to or greater than a predetermined first threshold.

[0039] The battery protection circuit 111 is composed of: a switching element S1 arranged between the second DC-DC converter 21 and the second battery 22; and a diode D1 connected in parallel with the switching element S1 and performing rectification in a direction from the second battery 22 to the second DC-DC converter 21. In response to control by the control section 121, the switching element S1 performs switching between the ON operation state (conduction) and the OFF operation state (non-conduction). Fig. 1, as the battery protection circuit 111, for example, an N-channel MOSFET (field effect transistor) is used which has a body diode formed between the source and the drain.

[0040] The control section 121 is implemented, for example, by a microprocessor. The control section 121 can monitor the energy storage state of the second battery 22 by detecting a voltage, a temperature, or the like, and control the ON and OFF operations of the battery protection circuit 111 based on this energy storage state, as described below. steering

[0041] Next, a control of the secondary system power supply device of the redundant power supply system 1 according to the first example is also described with reference to Fig. 2A and Fig. 2B. Fig. 2A and Fig. 2B show states of the battery protection circuit 111 controlled by the control section 121 not shown therein.

[0042] Fig. 2A shows a case where the second battery 22 is in a normal state with respect to its stored energy amount. The normal state refers to a state other than a first state described later. In this normal state, the switching element S1 is controlled by the control section 121 to be subjected to the ON operation. In this control state, power output from the second DC-DC converter 21 is supplied to the second automatic driving system 23 and is used to charge the second battery 22 (charging can be performed). In addition, in this control state, it is also possible to supply power stored in the second battery 22 to the second automatic driving system 23 (assistance can be performed).

[0043] Fig. 2B illustrates a case where the second battery 22 is in a first state in which its stored energy amount is equal to or greater than a predetermined first threshold. In this first state, the switching element S1 is controlled by the control section 121 to be subjected to the OFF operation. In this control state, a charging path from the second DC-DC converter 21 to the second battery 22 is cut off, so that charging of the second battery 22 by power output from the second DC-DC converter 21 is disabled (charging is prohibited). Therefore, for example, the second battery 22, which is in a fully charged state when its stored energy amount is equal to or greater than the first threshold, can be prevented from being further charged.On the other hand, in this control state, a discharge path from the second battery 22 to the second automatic driving system 23 is ensured through the diode D1, and thus the second battery 22 can be made to quickly function as an assist power supply for operating the second automatic driving system 23 when necessary (assistance can be performed). Operation and effects

[0044] In the redundant power supply system 1 according to the first example described above, the switching element S1 and the diode D1 that performs rectification in the opposite direction to the path are provided on a path from the second DC-DC converter 22 to the second battery 22. When the second battery 22 is in the first state with respect to its stored energy amount, the switching element S1 is turned off to interrupt the charging path, so that only the discharging path extending via the diode D1 is formed.

[0045] Accordingly, overcharging of the second battery 22 in the fully charged state in which the stored energy amount thereof is equal to or greater than the first threshold value can be prevented, and the second battery 22 can be caused to quickly function as an auxiliary power supply for operating the second automatic driving system 23 when necessary. Second unclaimed example configuration

[0046] Fig. Fig. 3 is a block diagram showing a schematic configuration of a redundant power supply system 2 according to a second unclaimed example of the present invention. The configuration of the Fig. The redundant power supply system 2 shown as an example in Figure 3 differs from the redundant power supply system 1 according to the first example described above in that a third DC-DC converter (DDC) 132 and an energy storage section 142 are additionally provided, and the control section 121 is replaced with a control section 122 that differs from it in terms of control. The other components of the redundant power supply system 2 are identical to those of the redundant power supply system 1 described above. Therefore, these components are denoted by the same reference numerals, and their description is omitted.

[0047] The third DC-DC converter 132 is connected between the energy storage section 142 and a connection point between the battery protection circuit 111 and the second battery 22. The third DC-DC converter 132 is configured, according to control by the control section 122, to discharge a portion of the energy stored in the second battery 22 to the energy storage section 142 and to return the energy stored in the energy storage section 142 as a result of the discharge to the second battery 22 side to discharge the second battery 22.

[0048] The energy storage section 142 is an energy storage element, such as a capacitor, configured to charge / discharge energy. The energy storage section 142 may be a lead-acid battery, a lithium-ion battery, or the like, as long as it is configured to charge / discharge energy.

[0049] The control section 122 is implemented, for example, by a microcomputer. Like the above-described control section 121 according to the first example, the control section 122 can monitor the energy storage state of the second battery 22 and control the ON and OFF operations of the battery protection circuit 111 based on this energy storage state. Furthermore, the control section 122 can control the third power converter 132 as described below to determine the deterioration state of the second battery 22. steering

[0050] Hereinafter, the control by the secondary system power supply device of the redundant power supply system 2 according to the second example is also explained with reference to Fig. 4A and Fig. 4B. Fig. 4A and Fig. 4B illustrate states of the battery protection circuit 111 and the third DC-DC converter 132, which are controlled by the control section 122 not shown here.

[0051] Fig. 4A illustrates a case where the second battery 22 is in the above-described first state with respect to its stored energy amount. In this first state, the control section 122 instructs the third DC-DC converter 132 to perform a check discharge. The check discharge is a process of discharging a portion of the energy stored in the second battery 22 to the energy storage section 142. Through this check discharge, the control section 122 can determine the deterioration state of the second battery 22 based on an internal resistance value of the second battery 22, which is estimated from the difference in the voltage value of the second battery 22 between before and after the discharge, and a discharge current value. In the first state, the check discharge can be performed at an arbitrary time and an arbitrary interval.

[0052] Furthermore, Fig. 4B illustrates a case where the second battery 22 is in the first state with respect to its stored energy amount. When the deterioration state of the second battery 22 is determined by the check discharge, the control section 122 instructs the third DC-DC converter 132 to perform regeneration charging. Regeneration charging is a process in which energy moved from the second battery 22 to the energy storage section 142 during the check discharge is recovered to the second battery 22. This regeneration charging prevents energy from being wasted for determining the deterioration state of the second battery 22. Operation and effects

[0053] The above-described redundant power supply system 2 according to the second example includes the energy storage section 142 and the third DC-DC converter 132 for discharging a portion of energy stored in the second battery 22 to the energy storage section 142. When the discharge path from the second DC-DC converter 21 is interrupted, discharging is performed from the second battery 42 to the energy storage section 142, and the deterioration state of the second battery 22 is determined.

[0054] Accordingly, discharging can be performed using the energy storage section 142 without being affected by a charging operation performed on the second battery 22 by the second DC-DC converter 21, whereby the deterioration state of the second battery 22 can be accurately determined. Third unclaimed example configuration

[0055] Fig. 5 shows a block diagram illustrating a schematic configuration of a redundant power supply system 3 according to a third unclaimed example. Fig. The redundant power supply system 3 shown as an example in FIG. 5 differs in configuration from the redundant power supply system 1 according to the first example described above in that the battery protection circuit 111 is replaced by a battery protection circuit 113 and the control section 121 is replaced by a control section 123. The other components of the redundant power supply system 3 are identical to those of the redundant power supply system 1 described above. Therefore, these components are denoted by the same reference numerals, and their description is omitted.

[0056] The battery protection circuit 113 is a relay circuit arranged between the second DC-DC converter 21 and the second battery 22, and serves to prevent overcharging and excessive discharging (overdischarging) of the second battery 22. The term "overcharging" refers to a state in which the second battery 22 continues to be charged from the fully charged state in which the stored energy amount of the second battery 22 is equal to or greater than the predetermined first threshold. The term "overdischarging" refers to a state in which the second battery 22 continues to be discharged from a nearly discharged state in which the stored energy amount of the second battery 22 is equal to or less than a predetermined second threshold, which is less than the first threshold.

[0057] The battery protection circuit 113 is composed of: the switching element S1 and a switching element S2 arranged between the second DC-DC converter 21 and the second battery 22; the diode D1 connected in parallel with the switching element S1 and performing rectification in a direction from the second battery 22 to the second DC-DC converter 21; and a diode D2 connected in parallel with the switching element S2 and performing rectification in a direction from the second DC-DC converter 21 to the second battery 22. In response to control by the control section 123, the switching element S1 and the switching element S2 each perform switching between the ON (conduction) state and the OFF (non-conduction) state. Fig. 5, for example, an N-channel MOSFET having a body diode formed between the source and the drain is used as the battery protection circuit 113.

[0058] The control section 193 is implemented, for example, by a microcomputer. The control section 123 can monitor the energy storage state of the second battery 22 by detecting a voltage, a temperature, or the like, and control the ON and OFF operations of the battery protection circuit 113 based on this energy storage state, as described below. steering

[0059] Next, a control by the secondary system power supply device of the redundant power supply system 3 according to the third example is also described with reference to Fig. 6A to 6C. Fig. 6A to 6C show states of the battery protection circuit 113 controlled by the control section 123 not shown here.

[0060] Fig. 6A shows a case where the second battery 22 is in a normal state with respect to its stored energy amount. The normal state refers to a state that is neither the first state described above nor a second state described later. In this normal state, both the switching element S1 and the switching element S2 are controlled by the control section 123 to undergo the ON operation. In this control state, power output from the second DC-DC converter 21 is supplied to the second automatic driving system 23 and is used to charge the second battery 22 (charging can be performed). In addition, in this control state, it is also possible to supply power stored in the second battery 22 to the second automatic driving system 23 (assistance can be performed).

[0061] Fig. 6B shows a case where the second battery 22 is in a second state in which its stored energy amount is equal to or less than a predetermined second threshold, which is smaller than the above-described first threshold. In this state, the control section 132 performs control such that the switching element S1 is subjected to the ON operation and the switching element S2 is subjected to the OFF operation. In this control state, the discharge path from the second battery 22 to the second DC-DC converter 21 is interrupted, so that the discharge of energy from the second battery 22 to the second automatic driving system 23 is disabled (discharging is prohibited). Therefore, for example, further discharge of the second battery 22 in a nearly discharged state can be prevented.On the other hand, in this control state, the charging path from the second DC-DC converter 21 to the second battery 22 is ensured by the switching element S1 and the diode D2, and thus the second battery 22 can be charged until it is fully charged (charging can be performed).

[0062] Fig. 6C shows a case where the second battery 22 is in the first state in which its stored energy amount is equal to or greater than the predetermined first threshold. In this first state, the control section 123 performs control such that the switching element S1 is subjected to the OFF operation and the second switching element S2 is subjected to the ON operation. In this control state, the charging path from the second DC-DC converter 21 to the second battery 22 is interrupted, so that charging of the second battery 22 by power output from the second DC-DC converter 21 is disabled (charging is prohibited). Therefore, for example, further charging of the second battery 22 in the fully charged state in which its stored energy amount is equal to or greater than the first threshold can be prohibited.On the other hand, in this control state, the discharge path from the second battery 22 to the second automatic driving system 23 is ensured by the switching element S2 and the diode D1, and thus the second battery 22 can be caused to quickly function as an assist power supply for operating the second automatic driving system 23 when necessary (assistance can be performed). Operation and effects

[0063] In the redundant power supply system 3 according to the third example described above, two switching elements, i.e., switching elements S1 and S2, and two diodes, i.e., diodes D1 and D2, which perform rectification in opposite directions, are provided between the second DC-DC converter 21 and the second battery 22. When the second battery 22 is in the first state in terms of its stored energy amount, the switching element S1 is turned off to interrupt the charging path, so that only a discharging path extending via the switching element S2 and the diode D1 is formed. When the second battery 22 is in the second state in terms of its stored energy amount, the switching element S2 is turned off to interrupt the discharging path, so that only a charging path extending via the switching element S1 and the diode D2 is formed.

[0064] Accordingly, overcharging of the second battery 92 in the fully charged state in which the stored energy amount thereof is equal to or greater than the first threshold can be prevented, and the second battery 22 can be caused to be quickly used as an auxiliary power supply for operating the second automatic driving system 23 when necessary.

[0065] Furthermore, over-discharge of the second battery 23 in the nearly discharged state can be prevented. Example configuration

[0066] Fig. 7 shows a block diagram illustrating a schematic configuration of a redundant power supply system 4r according to an embodiment of the present invention. The system shown as an example in Fig. The redundant power supply system 4 shown in Figure 7 differs in configuration from the redundant power supply system 1 according to the first example described above in that a third DC-DC converter (DDC) 134 is additionally provided, and the control section 121 is replaced by a control section 124 that differs from it in control. The other components of the redundant power supply system 4 are identical to those of the redundant power supply system 1 described above. Therefore, these components are denoted by the same reference numerals, and their description is omitted.

[0067] The third DC-DC converter 134 is connected between the connection point between the battery protection circuit 111 and the second battery 22 and a connection point between the first DC-DC converter 11 and the first battery 12 in the primary system. The third DC-DC converter 134 is configured to be able to discharge a portion of the energy stored in the second battery 22 to the first battery 12 according to control by the control section 124.

[0068] The control section 124 is implemented, for example, by a microcomputer. Like the above-described control section 121 according to the first example, the control section 124 can monitor the energy storage state of the second battery 22 and control the ON and OFF operations of the battery protection circuit 111 based on this energy storage state. Furthermore, the control section 124 can control the third DC-DC converter 134 as described below to determine the deterioration state of the second battery 22. steering

[0069] Next, a control by the secondary system power supply device of the redundant power supply system 4 according to the embodiment is also described with reference to Fig. 8 described. Fig. 8 shows a state of the battery protection circuit 111 and the third DC-DC converter 134, which is controlled by the control section 124 not shown here.

[0070] Fig.8 shows a case where the second battery 22 is in the above-described first state with respect to its stored energy amount. In this first state, the control section 124 instructs the third DC-DC converter 134 to perform the check discharge. The check discharge refers to a process of discharging a portion of energy stored in the second battery 22 to the first battery 12. Through this check discharge, the control section 124 can determine the deterioration state of the second battery 22 based on an internal resistance value of the second battery 22 estimated from the difference in the voltage value of the second battery 22 between before and after the discharge and a discharge current value. In the first state, the check discharge can be performed at an arbitrary time and an arbitrary interval. Operation and effects

[0071] The above-described redundant power supply system 4 according to the embodiment of the present invention includes the third DC-DC converter 134 for discharging a portion of energy stored in the second battery 22 to the first battery 12. When the charging path from the second DC-DC converter 21 is interrupted, discharging from the second battery 12 to the first battery 12 is performed, and the deterioration state of the second battery 22 is determined.

[0072] Accordingly, discharging can be performed using the first battery 12 without being affected by the charging performed on the second battery 22 by the second DC-DC converter 21, whereby the deterioration state of the second battery 22 can be accurately determined. In addition, since the discharge target is the first battery 12, the value of the current discharged for inspection can be set to be larger than the value of the current to be discharged to the power storage section 142 according to the second example described above, whereby the deterioration state of the second battery 22 can be determined with higher accuracy.Furthermore, since the discharge target is the first battery 12, the energy subjected to the check discharge can be efficiently used in the primary system, thereby making it possible to eliminate time and effort for recovering the energy as in the case where the energy storage section 142 is used. Other embodiments

[0073] The battery protection circuit 111 in the redundant power supply system 2 according to the second example and the redundant power supply system 4 according to the embodiment may be replaced by the battery protection circuit 113 explained in the description of the redundant power supply system 3 according to the third example.

[0074] Although the invention has been described in detail, the foregoing description is in all respects illustrative and not restrictive.

[0075] As described above, a redundant power supply system in which a predetermined power is supplied via a first DC-DC converter (DDC) to a first battery and a first load of a primary system, and the predetermined power is supplied via a second DDC to a second battery and a second load of a secondary system independent of the primary system, comprises: a first switching element arranged between the second DDC and the second battery, a first diode connected in parallel with the first switching element and conducting rectification in a direction from the second battery to the second DDC, and a control section that turns off the first switching element when the second battery is in a first state in which its stored energy amount is not less than a predetermined first threshold and turns on the first switching element,if a state other than the first state is assumed.,

Claims

[1] Redundant power supply system (1, 2, 3, 4) in which a predetermined energy is supplied to a first battery (12) and a first load (13, 14) of a primary system via a first DC-DC converter (11), and the predetermined energy is supplied to a second battery (22) and a second load (23) of a secondary system which is independent of the primary system via a second DC-DC converter (21), the redundant power supply system (1, 2, 3, 4) comprising: a first switching element (S1) arranged between the second DC-DC converter (21) and the second battery (22), a first diode (D1) connected in parallel to the first switching element (S1) and configured to perform rectification in a direction from the second battery (22) to the second DC-DC converter (21), and a control section (121, 122, 123, 124) configured to turn off the first switching element (S1) when the second battery (22) is in a first state in which its stored energy amount is equal to or greater than a predetermined first threshold value, and to turn on the first switching element (S1) when the second battery (22) is in a state other than the first state, and a third DC-DC converter (134) through which the second battery (22) and the first battery (12) are connected to each other to be chargeable and dischargeable, wherein in the first state in which the first switching element (S1) is turned off, the control section (124) causes the third DC-DC converter (134) to discharge a part of energy stored in the second battery (22) using the first battery (12), thereby determining a deterioration state of the second battery (22). [2] Redundant power supply system according to claim 1, further comprising a second switching element (S2) arranged between the second DC-DC converter (21) and the second battery (22) so as to be connected in series with the first switching element (S1), and a second diode (D2) connected in parallel to the second switching element (S2) and configured to perform rectification in a direction from the second DC-DC converter (21) to the second battery (22), wherein the control section (123) the second switching element (S2) switches off when the second battery (22) is in a second state in which its stored energy quantity is equal to or less than a predetermined second threshold value which is less than the first threshold value, and the second switching element (S2) switches on when the second battery (22) is in a state other than the second state. [3] Redundant power supply system according to claim 1 or 2, further comprising an energy storage section (142), and a third DC-DC converter (132) via which the second battery (22) and the energy storage section (142) are connected to each other in order to be chargeable and dischargeable, wherein in the first state in which the first switching element (S1) is turned off, the control section (122) causes the third DC-DC converter (132) to discharge a part of energy stored in the second battery (22) using the energy storage section (142), thereby determining a deterioration state of the second battery. [4] A redundant power supply system according to any one of claims 1 to 3, wherein an arrangement in which the first switching element (S1) and the first diode (D1) are connected in parallel and an arrangement in which the second switching element (S2) and the second diode (D2) are connected in parallel are each implemented by a field effect transistor having a body diode formed between a source and a drain.

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