Backup power supply system and mobile body

Abstract

This backup power supply system comprises a first terminal, a second terminal, a third terminal, a main power supply path, a power storage unit, a charge / discharge unit, a current detection unit, an auxiliary power supply path, a switch, and a control unit. The first terminal is connected to the main power supply. The second terminal is connected to a first load having a capacitor. The charge / discharge unit is connected between the main power supply path and the power storage unit. The current detection unit is disposed between the charge / discharge unit and the second terminal and detects current. The auxiliary power supply path connects the power storage unit and the second terminal. The switch is disposed in the auxiliary power supply path. When the current value of the current detected by the current detection unit becomes equal to or greater than a current threshold, the control unit outputs a control signal for bringing the switch into a conductive state to the switch.

Description

Backup power system and mobile

[0001] The present disclosure generally relates to a backup power supply system and a mobile body, and more particularly to a backup power supply system including a power storage unit and a mobile body including the backup power supply system.

[0002] Patent Document 1 discloses a vehicle including a first power source, a backup power source, and a plurality of auxiliary devices. In this vehicle, if the first power source fails, the backup power source supplies power to the plurality of auxiliary devices.

[0003] Japanese Patent Application Laid-Open No. 2021-136823

[0004] A backup power supply system according to one aspect of the present disclosure includes a first terminal, a second terminal, a third terminal, a main power supply path, a power storage unit, a charge / discharge unit, a current detection unit, an auxiliary power supply path, a switch, and a control unit. The first terminal is connected to a main power supply. The second terminal is connected to a first load having a capacitor. The third terminal is connected in parallel with the second terminal and to a second load. The main power supply path connects the first terminal and the second terminal. The charge / discharge unit is connected between the main power supply path and the power storage unit. In a non-failure state in which the main power supply is not faulty, the charge / discharge unit receives power from the main power supply and flows a charging current to the power storage unit. In a failure state in which the main power supply is faulty, the charge / discharge unit receives power from the power storage unit and flows a discharging current to the main power supply path. The current detection unit is disposed between the charge / discharge unit and the second terminal and detects a current. The auxiliary power supply path connects the power storage unit and the second terminal. The switch is disposed in the auxiliary power path and is configured to be switchable between a conductive state and a cut-off state. The control unit outputs a control signal to the switch for controlling the switching of the switch. The control unit outputs the control signal to the switch to switch the switch into the conductive state when the current value detected by the current detection unit is equal to or greater than a current threshold.

[0005] A mobile body according to one aspect of the present disclosure includes the backup power supply system, and a mobile body body that mounts the backup power supply system, the main power supply, the first load, and the second load.

[0006] According to the present disclosure, it is possible to stabilize the power supply to the load.

[0007] Fig. 1 is a schematic block diagram showing a backup power supply system according to a first embodiment. Fig. 2 is a schematic block diagram showing another state of the backup power supply system according to the same. Fig. 3 is a schematic diagram of a vehicle equipped with the backup power supply system according to the same. Fig. 4 is a schematic block diagram showing a backup power supply system according to a second embodiment. Fig. 5 is a schematic block diagram showing a backup power supply system according to a third embodiment. Fig. 6 is a schematic block diagram showing a backup power supply system according to a fourth embodiment. Fig. 7 is a schematic block diagram showing a backup power supply system according to a fifth embodiment. Fig. 8 is a schematic block diagram showing a backup power supply system according to a sixth embodiment.

[0008] In the backup power supply (backup power supply system) of Patent Document 1, if an inrush current occurs in one of multiple auxiliaries (loads) when power is supplied from the backup power supply to the multiple auxiliaries, there is a risk that the power supply to the other auxiliaries will become unstable.

[0009] The present disclosure has been made in view of the above-mentioned circumstances, and provides a backup power supply system and a mobile body that can stabilize the power supply to a load.

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Elements common to the embodiments described below are designated by the same reference numerals, and redundant descriptions of the common elements may be omitted. The following embodiments and modifications are merely a portion of the various embodiments of the present disclosure. Various modifications of the following embodiments and modifications may be made depending on the design, etc., as long as the object of the present disclosure can be achieved. The configurations of the modifications may also be combined as appropriate.

[0011] The drawings described in this disclosure are schematic drawings, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0012] First Embodiment (1) Overview First, an overview of a backup power supply system 2 according to a first embodiment will be described with reference to FIGS. 1 and 2. FIG.

[0013] The backup power supply system 2 of embodiment 1 includes a first terminal 21, a second terminal 22, a third terminal 23, a main power supply path 6, a charge / discharge unit 7, a current detection unit 10, an auxiliary power supply path 8, a storage unit 9, a switch S1, and a control unit 11.

[0014] The first terminal 21 is connected to the main power supply 3 .

[0015] A first load 4 having a capacitor C1 is connected to the second terminal 22.

[0016] The third terminal 23 is connected in parallel with the second terminal 22. The third terminal 23 is connected to the second load 5.

[0017] The main power supply path 6 connects the first terminal 21 and the second terminal 22 .

[0018] The charging / discharging unit 7 is connected between the main power supply path 6 and the power storage unit 9. In a normal state where the main power supply 3 is not faulty, the charging / discharging unit 7 receives power from the main power supply 3 and passes a charging current to the power storage unit 9, and in a fault state where the main power supply 3 is faulty, the charging / discharging unit 7 receives power from the power storage unit 9 and passes a discharging current I1 to the main power supply path 6.

[0019] Here, the failure state of the main power supply 3 refers to a state in which the voltage input from the main power supply 3 to the first terminal 21 drops below a predetermined threshold due to a malfunction of the main power supply 3, a ground fault in the main power supply 3 or in the circuit connecting the main power supply 3 and the first terminal 21, etc. The non-failure state of the main power supply 3 refers to a state in which the voltage input from the main power supply 3 to the first terminal 21 is equal to or higher than the threshold. The predetermined threshold is preferably set to a voltage lower than the rated voltage of the main power supply 3, for example, and higher than the minimum guaranteed voltage required for the first load 4 and the second load 5 to operate normally.

[0020] The current detection unit 10 is disposed between the charge / discharge unit 7 and the second terminal 22. The current detection unit 10 detects the current between the charge / discharge unit 7 and the second terminal 22.

[0021] The auxiliary power supply path 8 connects the power storage unit 9 and the second terminal 22 .

[0022] The switch S1 is disposed on the auxiliary power path 8. The switch S1 is configured to be switchable between a conductive state and a cut-off state.

[0023] The control unit 11 outputs a control signal S0 to the switch S1 to control switching of the switch S1. When the current value detected by the current detection unit 10 is equal to or greater than a current threshold, the control unit 11 outputs the control signal S0 to the switch S1 to turn the switch S1 on.

[0024] Because the first load 4 is a load having a capacitor C1, an inrush current may occur when a discharge current I1 flows from the power storage unit 9 to the first load 4. In the backup power supply system 2 of the first embodiment, the switch S1 becomes conductive when the current value detected by the current detection unit 10 disposed between the charge / discharge unit 7 and the second terminal 22 becomes equal to or greater than the current threshold. As a result, even if an inrush current flows from the charge / discharge unit 7 to the first load 4 and the output voltage of the charge / discharge unit 7 drops, power is supplied from the power storage unit 9 to the main power supply path 6 via the auxiliary power supply path 8. In other words, in the backup power supply system 2 of the first embodiment, when the output voltage of the charge / discharge unit 7 drops, the power storage unit 9 assists in the supply of power to the first load 4 and the second load 5.

[0025] Therefore, according to the backup power supply system 2 of the first embodiment, even if an inrush current flows from the charge / discharge unit 7 to the first load and the output voltage of the charge / discharge unit 7 drops, power can be stably supplied to the second load 5 connected to the main power supply path 6. In other words, according to the backup power supply system 2 of the first embodiment, it is possible to stabilize the power supply to loads such as the first load 4 and the second load 5.

[0026] (2) Details The detailed configuration of the backup power supply system 2 according to the first embodiment will be described below with reference to FIGS. 1 to 3. FIG.

[0027] As shown in FIG. 3 , the backup power supply system 2 of the first embodiment is mounted on a mobile object such as a vehicle 100. That is, the mobile object (vehicle 100) includes the backup power supply system 2 and a mobile object body 101 (e.g., the body of the vehicle 100). The mobile object body 101 is equipped with an ECU (Electronic Control Unit) 1, the backup power supply system 2, a main power supply 3, a first load 4, and a second load 5. In a failure state in which the main power supply 3 (e.g., the battery of the vehicle 100) of the vehicle 100 fails, the backup power supply system 2 supplies power from a power storage unit 9 to the first load 4 and the second load 5 (e.g., an electric brake system, etc.). As a result, the first load 4 and the second load 5 can continue to operate using the power supply from the power storage unit 9 even in a failure state of the main power supply 3. 3 is a conceptual diagram showing the state in which backup power supply system 2 is mounted on vehicle 100, and does not limit the mounting position of backup power supply system 2. Backup power supply system 2 is generally mounted in a position from the engine compartment to the console box at the front of vehicle 100, but the mounting position of backup power supply system 2 can be changed as appropriate.

[0028] Although the first embodiment illustrates a case where the backup power supply system 2 is mounted on the vehicle 100, the mobile body is not limited to the vehicle 100, but may be an airplane, a ship, a train, etc. Furthermore, the backup power supply system 2 is not limited to being mounted on a mobile body, but may be installed and used in a facility, etc.

[0029] 1 and 2, the backup power supply system 2 of the first embodiment includes a first terminal 21, a second terminal 22, a third terminal 23, a main power supply path 6, a charge / discharge unit 7, an auxiliary power supply path 8, a power storage unit 9, a current detection unit 10, a control unit 11, and a switch S1. The second terminal 22 and the third terminal 23 are connected in parallel with each other.

[0030] A main power supply 3 such as a battery of the vehicle 100 is connected to the first terminal 21 .

[0031] A first load 4 is connected to the second terminal 22. The first load 4 is a load having a capacitor C1 with a relatively large capacitance. The capacitance of the capacitor C1 of the first load 4 is, for example, 1 mF. The first load 4 in the first embodiment is a load having a motor such as a power window.

[0032] A second load 5 is connected to the third terminal 23. The second load 5 is a load for which an instantaneous power outage is undesirable (or unacceptable). The second load 5 in the first embodiment is an ECU-related load that is reset when an instantaneous power outage occurs.

[0033] The first terminal 21, the second terminal 22, and the third terminal 23 may be components (terminals) for connecting electric wires, etc., but may also be, for example, leads of electronic components or parts of conductors formed as wiring on a circuit board.

[0034] The main power supply path 6 connects the first terminal 21 to the second terminal 22 and the third terminal 23. The main power supply path 6 is a current path from the main power supply 3 to the first load 4 and the second load 5 in a normal state where the main power supply 3 is not faulty.

[0035] The power storage unit 9 is disposed between the auxiliary power supply path 8 and ground. A first end of the power storage unit 9 is connected to the auxiliary power supply path 8, and a second end of the power storage unit 9 is connected to ground. The power storage unit 9 functions as an auxiliary power supply for supplying power to the first load 4 and the second load 5 in a failure state in which the main power supply 3 fails. The power storage unit 9 includes, for example, an electric double layer capacitor (EDLC) capable of rapid charging and discharging. In other words, the backup power supply system 2 includes an electric double layer capacitor. The power storage unit 9 may be configured with two or more power storage devices (e.g., electric double layer capacitors) electrically connected in parallel, in series, or in parallel and in series. In other words, the power storage unit 9 may be realized by a parallel circuit or a series circuit of two or more power storage devices, or a combination thereof.

[0036] The charging / discharging unit 7 is connected (or disposed) between the main power supply path 6 and the power storage unit 9. When the main power supply 3 is in a normal state, the charging / discharging unit 7 receives power from the main power supply 3 and passes a charging current to the power storage unit 9. When the main power supply 3 is in a fault state, the charging / discharging unit 7 receives power from the power storage unit 9 and passes a discharging current I1 to the first load 4 and the second load 5. As shown in FIG. 1 , the discharging current I1 flows to the first load 4 and the second load 5 via the path of the power storage unit 9 - connection point 81 - the charging / discharging unit 7 - connection point 61 - the current detection unit 10 - connection point 62 - connection point 63. Note that the connection point 81 is the connection point between the power storage unit 9 and the auxiliary power supply path 8. The connection point 61 is the connection point between the main power supply path 6 and the charging / discharging unit 7, the connection point 62 is the connection point between the main power supply path 6 and the auxiliary power supply path 8, and the connection point 63 is the connection point between the main power supply path 6 and the third terminal 23.

[0037] The charge / discharge unit 7 is, for example, a bidirectional DC-DC converter, and includes a step-up / step-down circuit including a switching element and the like, and a control unit 71.

[0038] The control unit 71 is configured, for example, by a microcomputer having a processor and memory. In other words, the control unit 71 is realized by a computer system having a processor and memory. The processor executes an appropriate program, causing the computer system to function as the control unit 71. The program may be pre-recorded in the memory, or may be provided via a telecommunications line such as the Internet, or recorded on a non-transitory recording medium such as a memory card. Note that the control unit 71 is not limited to being realized by a computer system, and may also be realized by an analog circuit, a gate drive circuit, or the like.

[0039] The control unit 71 compares the main voltage, which is the voltage of the main power supply 3, with the set voltage, and controls the step-up / step-down circuit so that a charging operation is performed if the main voltage is equal to or higher than the set voltage, and a discharging operation is performed if the main voltage is lower than the set voltage. As a result, if the main voltage is equal to or higher than the set voltage, the charge / discharge unit 7 operates to pass a charging current to the power storage unit 9, and if the main voltage is lower than the set voltage, the charge / discharge unit 7 operates to pass a discharging current I1 from the power storage unit 9 to the main power supply path 6.

[0040] The auxiliary power supply path 8 connects the power storage unit 9 and the main power supply path 6. The auxiliary power supply path 8 is a current path from the power storage unit 9 to the first load 4 and the second load 5 when the switch S1 is in the conductive state.

[0041] The current detection unit 10 is disposed between the charge / discharge unit 7 and the second terminal 22 and the third terminal 23. The current detection unit 10 of the first embodiment is disposed in the main power supply path 6, between the connection point 61 and the connection point 62.

[0042] The current detection unit 10 detects at least the discharge current I1 flowing from the charge / discharge unit 7. In the first embodiment, the current detection unit 10 includes a detection resistor and detects the current value of the current flowing through the detection resistor. The current detection unit 10 outputs the detection result to the control unit 11. Note that the current detection unit 10 may be a non-contact current sensor.

[0043] The switch S1 is disposed in the auxiliary power supply path 8. The switch S1 is configured to be switchable between a conductive state and a cut-off state. More specifically, the switch S1 is switched between a conductive state in which at least a current flows from the power storage unit 9 to the main power supply path 6 and a cut-off state in which bidirectional current is cut off, in response to a control signal S0 input from the control unit 11. The switch S1 is, for example, a transistor. However, the switch S1 is not limited to a transistor, and may be configured to be switchable between a conductive state and a cut-off state in response to the control signal S0 input from the control unit 11. Note that the switch S1 in the first embodiment is controlled to be in the cut-off state except when the switch S1 is in the conductive state in response to the control signal S0 input from the control unit 11.

[0044] The control unit 11 outputs a control signal S0 to the switch S1 to control switching of the switch S1. The control unit 11 controls the switch S1 to a conductive state or a cut-off state depending on the detection result of the current detection unit 10. The control unit 11 is configured, for example, by a microcomputer having a processor and memory. That is, the control unit 11 is realized by a computer system having a processor and memory. The processor executes an appropriate program, causing the computer system to function as the control unit 11. The program may be pre-recorded in the memory, or may be provided via a telecommunications line such as the Internet, or recorded on a non-transitory recording medium such as a memory card. Note that the control unit 11 is not limited to being realized by a computer system, and may also be realized by an analog circuit, a gate drive circuit, or the like.

[0045] When the current value of the discharge current I1 detected by the current detection unit 10 becomes equal to or greater than the current threshold, the control unit 11 outputs a control signal S0 to the switch S1 to turn on the switch S1. When the current value of the discharge current I1 detected by the current detection unit 10 becomes equal to or greater than the current threshold, the control unit 11 in the first embodiment outputs a control signal S0 to the switch S1 to turn on the switch S1. Here, the current threshold is a value at which an inrush current is considered to have flowed from the charge / discharge unit 7 to the first load 4, and is a value greater than the current value of the current flowing from the charge / discharge unit 7 to the main power supply path 6 in a steady state at the time of a failure. The current threshold is also a value greater than the current value of the current flowing from the main power supply 3 to the main power supply path 6.

[0046] 2 , when the control unit 11 places the switch S1 in a conductive state, the power storage unit 9 and the main power supply path 6 are electrically connected. This enables power supply from the power storage unit 9 to the first load 4 and the second load 5. Therefore, when an inrush current flows from the charging / discharging unit 7 to the first load 4, causing a drop in the output voltage of the charging / discharging unit 7, a discharge current I2 flows from the power storage unit 9 to the main power supply path 6, and power is supplied from the power storage unit 9 to the first load 4 and the second load 5. Note that the voltage value of the voltage output from the power storage unit 9 to the main power supply path 6 in the first embodiment is higher than the voltage value of the voltage output from the charging / discharging unit 7 to the main power supply path 6 in a non-fault state.

[0047] As described above, the backup power supply system 2 of embodiment 1 can stably supply power to the first load 4 and the second load 5 even if an inrush current flows from the charge / discharge unit 7 to the first load 4 when the main power supply 3 fails. In other words, the backup power supply system 2 can prevent the second load 5 from suffering an instantaneous power outage even if an inrush current flows from the charge / discharge unit 7 to the first load 4 when the main power supply 3 fails.

[0048] (3) Modifications Modifications of the first embodiment are listed below.

[0049] In the first embodiment, the charge / discharge unit 7 and the auxiliary power supply path 8 are connected, but the charge / discharge unit 7 and the auxiliary power supply path 8 do not have to be connected. In other words, the path connecting the power storage unit 9 and the charge / discharge unit 7 and the path connecting the power storage unit 9 and the auxiliary power supply path 8 may be separate paths.

[0050] In the first embodiment, an example is given in which two loads (first load 4 and second load 5) are connected to the backup power supply system 2, but three or more loads may be connected to the backup power supply system 2.

[0051] In embodiment 1, an example is given in which the current detection unit 10 is arranged in the main power supply path 6, but the current detection unit 10 may also be arranged between the charge / discharge unit 7 and the main power supply path 6 (connection point 61).

[0052] The power storage unit 9 is not limited to an electric double layer capacitor, but may be a secondary battery such as a lithium ion capacitor (LIC) or a lithium ion battery (LIB). In a lithium ion capacitor, the positive electrode is formed of a material similar to that of an EDLC (e.g., activated carbon), and the negative electrode is formed of a material similar to that of a LIB (e.g., a carbon material such as graphite).

[0053] The power storage unit 9 is not limited to an electric double layer capacitor, and may be, for example, an electrochemical device having the following configuration. The electrochemical device includes a positive electrode member, a negative electrode member, and a nonaqueous electrolyte. The positive electrode member includes a positive electrode current collector and a positive electrode material layer supported on the positive electrode current collector and containing a positive electrode active material. The positive electrode material layer includes a conductive polymer as a positive electrode active material that dopes and dedopes anions (dopants). The negative electrode member includes a negative electrode material layer containing a negative electrode active material. The negative electrode active material is, for example, a substance that undergoes an oxidation-reduction reaction involving the absorption and desorption of lithium ions, specifically, a carbon material, a metal compound, an alloy, or a ceramic material. The nonaqueous electrolyte, for example, has lithium ion conductivity. This type of nonaqueous electrolyte includes a lithium salt and a nonaqueous solution that dissolves the lithium salt. An electrochemical device configured in this manner has a higher energy density than an electric double layer capacitor or the like.

[0054] Second Embodiment A backup power supply system 2 according to a second embodiment will be described with reference to Fig. 4. The backup power supply system 2 of the second embodiment differs from the backup power supply system 2 of the first embodiment in that the control unit 11 includes a pulse generating unit 13.

[0055] The pulse generating unit 13 generates a pulse wave control signal S0. That is, the control signal S0 output by the control unit 11 in the second embodiment is a pulse wave signal. The pulse width (or on-time) of the control signal S0 output by the control unit 11 is set in advance, and is, for example, 500 μsec. The pulse width may be set appropriately depending on the capacitance of the capacitor C1 of the first load 4.

[0056] The switch S1 is in a conducting state while the pulse is being input.

[0057] According to the backup power supply system 2 of the second embodiment, it is possible to set in advance the period during which the switch S1 is in the conductive state, thereby preventing the switch S1 from being in the conductive state for a period longer than the preferred period, thereby preventing an overvoltage from being applied to the first load 4 and the second load 5.

[0058] Third Embodiment A backup power supply system 2 according to a third embodiment will be described with reference to Fig. 5. The backup power supply system 2 of the third embodiment differs from the backup power supply system 2 of the first embodiment in that it further includes a diode 14 for preventing backflow.

[0059] Diode 14 is arranged in auxiliary power supply path 8. Diode 14 in the third embodiment is arranged between connection point 81 and switch S1. Diode 14 is arranged such that the direction from power storage unit 9 to second terminal 22 in auxiliary power supply path 8 coincides with the forward direction of diode 14. That is, the cathode of diode 14 is connected to switch S1, and the anode of diode 14 is connected to connection point 81 (or power storage unit 9).

[0060] According to the backup power supply system 2 of the third embodiment, when the switch S1 is in a conductive state, it is possible to prevent current from flowing from the main power supply path 6 to the power storage unit 9 or the charge / discharge unit 7.

[0061] The diode 14 may be disposed between the switch S1 and the main power supply path 6 (connection point 62).

[0062] Fourth Embodiment A backup power supply system 2 according to a fourth embodiment will be described with reference to Fig. 6. The backup power supply system 2 of the fourth embodiment differs from the backup power supply system 2 of the first embodiment in that it further includes a voltage detection unit 15.

[0063] The voltage detection unit 15 detects the voltage of the main power supply path 6. The voltage detection unit 15 of the fourth embodiment detects the voltage between the first terminal 21 of the main power supply path 6 and the current detection unit 10. The voltage detection unit 15 outputs the detection result to the control unit 11. Note that in this disclosure, "detecting the voltage between A and B" does not mean detecting the potential difference between the potential of A and the potential of B, but means detecting the potential difference between the potential between A and B and a reference potential (e.g., ground).

[0064] When the voltage value detected by voltage detection unit 15 becomes equal to or greater than the voltage threshold, control unit 11 outputs a control signal S0 to switch S1 to the cut-off state. In other words, after detecting an inrush current and turning on switch S1, control unit 11 turns switch S1 to the cut-off state when the voltage value of the output voltage of charge / discharge unit 7, which had decreased, recovers to the voltage threshold.

[0065] According to the backup power supply system 2 of the fourth embodiment, the switch S1 can be turned off at the timing when the charge / discharge unit 7 is able to stably supply power to the first load 4 and the second load 5 .

[0066] Furthermore, since the voltage detection unit 15 of embodiment 4 detects the voltage between the first terminal 21 and the current detection unit 10, it can more accurately detect that the output voltage of the charging / discharging unit 7 has recovered compared to when the voltage detection unit 15 detects the voltage between the current detection unit 10 and the second terminal 22.

[0067] Fifth Embodiment A backup power supply system 2 according to a fifth embodiment will be described with reference to Fig. 7. The backup power supply system 2 of the fifth embodiment differs from the backup power supply system 2 of the fourth embodiment in that the voltage detection unit 15 detects the voltage between the current detection unit 10 and the second terminal 22 in the main power supply path 6.

[0068] The voltage detection unit 15 of the fifth embodiment detects the voltage between the current detection unit 10 and the second terminal 22, and therefore can more accurately detect the voltages supplied to the first load 4 and the second load 5 compared to when the voltage detection unit 15 detects the voltage between the first terminal 21 and the current detection unit 10. This makes it possible to prevent an overvoltage from being applied to the first load 4 and the second load 5.

[0069] Sixth Embodiment A backup power supply system 2 according to a sixth embodiment will be described with reference to Fig. 8. The backup power supply system 2 of the sixth embodiment differs from the backup power supply system 2 of the first embodiment in that it further includes a capacitor 16.

[0070] Capacitor 16 is connected in parallel with power storage unit 9. That is, capacitor 16 is disposed between auxiliary power supply path 8 and ground. A first end of capacitor 16 is connected to auxiliary power supply path 8, and a second end of capacitor 16 is connected to ground. In the sixth embodiment, the first end of capacitor 16 is connected between power storage unit 9 (or connection point 81) and switch S1, but the first end of capacitor 16 may be connected between power storage unit 9 and charge / discharge unit 7.

[0071] Here, the power storage unit 9 in embodiment 6 is an electric double layer capacitor. The capacitor 16 is a surface-mount type or lead-type electrolytic capacitor, and may be an electrolytic capacitor that uses a conductive polymer or an electrolytic solution as the electrolyte, or may be a so-called hybrid type electrolytic capacitor that combines a conductive polymer and an electrolytic solution. In embodiment 6, the capacitor 16 is a hybrid type electrolytic capacitor. That is, in embodiment 6, the power storage unit 9 and the capacitor 16 are different types of capacitors. The internal resistance of the capacitor 16 is smaller than the internal resistance of the power storage unit 9. Furthermore, the capacitance of the capacitor 16 is smaller than the capacitance of the power storage unit 9.

[0072] When the switch S1 is in a conductive state, the capacitor 16 is able to supply power to the first load 4 and the second load 5. By connecting such a capacitor 16 in parallel with the power storage unit 9, it is possible to increase the amount of power supplied to the first load 4 and the second load 5 via the auxiliary power path 8 compared to, for example, the backup power supply system 2 of the first embodiment. This makes it possible to further stabilize the power supply to loads such as the first load 4 and the second load 5.

[0073] (Summary) As is clear from the above-described embodiment and modified examples, the backup power supply system (2) according to the first aspect includes a first terminal (21), a second terminal (22), a third terminal (23), a main power supply path (6), a power storage unit (9), a charge / discharge unit (7), a current detection unit (10), an auxiliary power supply path (8), a switch (S1), and a control unit (11). The first terminal (21) is connected to the main power supply (3). The second terminal (22) is connected to a first load (4) having a capacitor (C1). The third terminal (23) is connected in parallel with the second terminal (22) and is connected to a second load (5). The main power supply path (6) connects the first terminal (21) and the second terminal (22). The charge / discharge unit (7) is connected between the main power supply path (6) and the power storage unit (9). The charge / discharge unit (7) receives power from the main power supply (3) in a normal state where the main power supply (3) is not faulty and flows a charging current to the storage unit (9), and receives power from the storage unit (9) in a fault state where the main power supply (3) is faulty and flows a discharging current (I1) to the main power supply path (6). The current detection unit (10) is disposed between the charge / discharge unit (7) and the second terminal (22) and detects a current flowing between the charge / discharge unit (7) and the second terminal (22). The auxiliary power supply path (8) connects the storage unit (9) and the second terminal (22). The switch (S1) is disposed in the auxiliary power supply path (8) and is configured to be switchable between a conductive state and a cut-off state. The control unit (11) outputs a control signal (S0) to the switch (S1) for controlling the switching of the switch (S1). When the current value detected by the current detection unit (10) becomes equal to or greater than a current threshold, the control unit (11) outputs a control signal (S0) to the switch (S1) to turn the switch (S1) into a conductive state.

[0074] According to this aspect, it is possible to stabilize the power supply to the first load (4) and the second load (5).

[0075] In the backup power supply system (2) according to the second aspect, in the first aspect, the control signal (S0) is a pulse wave signal.

[0076] According to this aspect, it is possible to set in advance the period during which the switch (S1) is in a conductive state.

[0077] The backup power supply system (2) according to a third aspect is the backup power supply system (2) according to the first or second aspect, further comprising a diode (14) arranged in the auxiliary power supply path (8). The diode (14) is arranged so that the direction from the power storage unit (9) toward the second terminal (22) in the auxiliary power supply path (8) coincides with the forward direction of the diode (14).

[0078] According to this aspect, when the switch (S1) is in a conductive state, it is possible to prevent current from flowing from the main power supply path (6) to the storage unit (9) or the charge / discharge unit (7).

[0079] A backup power supply system (2) according to a fourth aspect is the backup power supply system (2) of any one of the first to third aspects, further comprising a voltage detection unit (15). The voltage detection unit (15) detects the voltage of the main power supply path (6). When the voltage value detected by the voltage detection unit (15) is equal to or greater than a voltage threshold, the control unit (11) outputs a control signal (S0) to the switch (S1) to turn the switch (S1) into an interrupted state.

[0080] According to this aspect, for example, the switch (S1) can be turned off at the timing when the charge / discharge unit (7) becomes able to stably supply power to the first load (4) and the second load (5).

[0081] In the backup power supply system (2) according to the fifth aspect, in the fourth aspect, the voltage detection unit (15) detects the voltage between the first terminal (21) of the main power supply path (6) and the current detection unit (10).

[0082] According to this aspect, it is possible to more accurately detect that the output voltage of the charge / discharge unit (7) has recovered.

[0083] In the backup power supply system (2) according to the sixth aspect, in the fourth aspect, the voltage detection unit (15) detects the voltage between the current detection unit (10) and the second terminal (22) in the main power supply path (6).

[0084] According to this aspect, the voltages supplied to the first load (4) and the second load (5) can be detected more accurately.

[0085] A backup power supply system (2) according to a seventh aspect is any one of the first to sixth aspects, further comprising a capacitor (16) connected in parallel with the power storage unit (9).

[0086] According to this aspect, the power supply to the first load (4) and the second load (5) can be further stabilized.

[0087] The configurations other than the first aspect are not essential for the backup power supply system (2) and can be omitted as appropriate.

[0088] A mobile body (vehicle 100) according to an eighth aspect includes the backup power supply system (2) according to any one of the first to seventh aspects and a mobile body (101). The mobile body (101) is equipped with the backup power supply system (2), a main power supply (3), a first load (4), and a second load (5).

[0089] According to this aspect, it is possible to stabilize the power supply to the first load (4) and the second load (5).

[0090] 2 Backup power supply system 3 Main power supply 4 First load 5 Second load 6 Main power supply path 7 Charging / discharging section 8 Auxiliary power supply path 9 Power storage section 10 Current detection section 11 Control section 14 Diode 15 Voltage detection section 16 Capacitor 21 First terminal 22 Second terminal 23 Third terminal 100 Vehicle (mobile body) 101 Mobile body C1 Capacitor I1 Discharge current S0 Control signal S1 Switch

Claims

1. A power supply comprising: a first terminal connected to a main power supply; a second terminal connected to a first load having a capacitor; a third terminal connected in parallel to the second terminal and connected to a second load; a main power supply path connecting the first terminal and the second terminal; a power storage unit; a charge / discharge unit connected between the main power supply path and the power storage unit, which receives power from the main power supply in a non-fault state where the main power supply is not faulty and causes a charging current to flow to the power storage unit, and receives power from the power storage unit in a fault state where the main power supply is faulty and causes a discharging current to flow to the main power supply path; a current detection unit disposed between the charge / discharge unit and the second terminal and detects a current flowing between the charge / discharge unit and the second terminal; an auxiliary power supply path connecting the power storage unit and the second terminal; a switch disposed on the auxiliary power supply path and configured to be switchable between a conductive state and a cut-off state; and a control unit which outputs a control signal to the switch for controlling the switching of the switch, the control unit outputs the control signal to the switch to turn the switch into a conductive state when the current value detected by the current detection unit is equal to or greater than a current threshold.

2. The backup power system according to claim 1, wherein the control signal is a pulse wave signal.

3. The backup power supply system according to claim 1, further comprising a diode arranged in the auxiliary power supply path, the diode being arranged such that a direction in the auxiliary power supply path from the power storage unit toward the second terminal coincides with a forward direction in the diode.

4. The backup power supply system according to claim 1, further comprising a voltage detection unit that detects the voltage of the main power supply path, and wherein the control unit outputs the control signal to the switch to turn off the switch when the voltage value detected by the voltage detection unit becomes equal to or greater than a voltage threshold.

5. The backup power supply system according to claim 4, wherein the voltage detection unit detects the voltage between the first terminal and the current detection unit in the main power supply path.

6. The backup power supply system according to claim 4, wherein the voltage detection unit detects the voltage between the current detection unit and the second terminal in the main power supply path.

7. The backup power supply system according to claim 1, further comprising a capacitor connected in parallel with the power storage unit.

8. A mobile body comprising: the backup power supply system according to any one of claims 1 to 7; and a mobile body on which the backup power supply system, the main power supply, the first load, and the second load are mounted.

Images