Backup power supply system and mobile body

Abstract

The backup power supply system 1 supplies power to one or more loads 3 in the event of a failure of a power source 2. The backup power supply system 1 includes a plurality of power storage devices C1 and a switching unit 12. The plurality of power storage devices C1 are charged by the power source 2. The switching unit 12 switches an electrical connection between the plurality of power storage devices C1 to a first state in which the plurality of power storage devices C1 are connected in parallel with the power source 2 or a second state in which the plurality of power storage devices C1 are connected in series with each other. The switching unit 12 switches the electrical connection to the first state when the plurality of power storage devices C1 are being charged, and switches the electrical connection to the second state in the event of a failure of the power source 2.

Description

Technical Field

[0001] This disclosure generally relates to backup power systems and mobile bodies. More specifically, this disclosure relates to a backup power system for supplying power to one or more loads in the event of a power failure, and a mobile body including such a backup power system. Background Technology

[0002] The boost power supply circuit (voltage conversion circuit) in Patent Document 1 supplies power from a lithium-ion battery (power storage device) as a backup power source to various types of loads when battery power supply is interrupted. The boost power supply circuit boosts the DC voltage supplied from the lithium-ion battery and supplies the boosted voltage to various types of loads.

[0003] Reference List

[0004] Patent documents

[0005] Patent Document 1: JP 2020-5481 A Summary of the Invention

[0006] Boost power supply circuits boost the output voltage of lithium-ion batteries and supply this boosted voltage to various types of loads in a single pass. Therefore, the boost power supply circuit needs to adaptively boost the voltage to a minimum guaranteed operating voltage higher than any other load of its type, and supply this boosted voltage in one pass. This results in very high and large voltage and current volumes that the boost power supply circuit must handle internally, potentially leading to a significant increase in internal noise.

[0007] Therefore, the purpose of this disclosure is to provide a backup power system and a mobile body, both of which are configured to reduce noise to be generated.

[0008] A backup power system according to one aspect of this disclosure supplies power to one or more loads in the event of a power failure. The backup power system includes multiple power storage devices and a switching unit. The multiple power storage devices are charged by the power source. The switching unit switches the electrical connection between the multiple power storage devices to a first state where the multiple power storage devices are connected in parallel with the power source, or a second state where the multiple power storage devices are connected in series with each other. The switching unit switches the electrical connection to the first state while the multiple power storage devices are being charged, and switches the electrical connection to the second state when a power failure occurs.

[0009] According to another aspect of this disclosure, the mobile body includes the aforementioned backup power system and the mobile body itself. The mobile body is equipped with the backup power system and one or more loads.

[0010] This disclosure achieves the advantage of reducing the noise that is to be generated. Attached Figure Description

[0011] Figure 1 This is a schematic circuit diagram of a backup power system according to an example embodiment;

[0012] Figure 2 This is a partial cross-sectional side view of a vehicle equipped with a backup power system.

[0013] Figure 3 This is a schematic circuit diagram showing the current path during the charging of a backup power system;

[0014] Figure 4 This is a schematic circuit diagram showing the current path in the event of a power failure in a backup power system.

[0015] Figure 5 This is a schematic circuit diagram showing the current path in the event of a power failure in a backup power system.

[0016] Figure 6 It is a schematic circuit diagram showing how the backup power system supplies power when the vehicle stops at a constant speed;

[0017] Figure 7 This is a schematic circuit diagram showing how the backup power system supplies power when the vehicle is remotely parked. Detailed Implementation

[0018] (Example)

[0019] (1) Overview

[0020] A backup power system 1 according to an exemplary embodiment will be described with reference to the accompanying drawings. Please note that the above embodiment is merely one exemplary embodiment among various embodiments of this disclosure and should not be construed as limiting. Rather, the exemplary embodiment can be readily modified in various ways according to design choices or any other factors without departing from the true spirit and scope of this disclosure.

[0021] like Figure 1 As shown, the backup power system 1 can be installed, for example, in vehicle 9 (see reference). Figure 2 If power source 2 (such as a battery) fails, backup power system 1 supplies power from multiple power storage devices C1 to one or more loads 3 (e.g., multiple loads in this embodiment). Even if power source 2 fails, one or more loads 3 are allowed to continue operating using the power supplied from the multiple power storage devices C1. As used herein, "power source 2 fails" means a situation where the power supply from power source 2 to load 3 is interrupted due to a failure, degradation, or disconnection of power source 2.

[0022] The backup power system 1 according to this embodiment includes a plurality of power storage devices C1 and a switching unit 12. The plurality of power storage devices C1 are charged by a power source 2. The switching unit 12 switches the electrical connection between the plurality of power storage devices C1 to a first state in which the plurality of power storage devices C1 are connected in parallel with the power source 2, or to a second state in which the plurality of power storage devices C1 are connected in series with each other. The switching unit 12 switches the electrical connection to the first state when the plurality of power storage devices C1 are being charged, and switches the electrical connection to the second state when the power source 2 fails.

[0023] During charging, multiple power storage devices C1 are connected in parallel with power supply 2. Compared to the case where multiple power storage devices C1 are connected in series, this allows charging of multiple power storage devices C1 at a lower voltage. Therefore, a charging circuit is not required to boost the voltage of power supply 2 to a higher voltage for charging multiple power storage devices C1, thus reducing the chance of noise and / or heat generated by the switching operation of the charging circuit. Furthermore, in the event of a failure of power supply 2, multiple power storage devices C1 are connected in series. Compared to the case where multiple power storage devices C1 are connected in parallel, this allows multiple power storage devices C1 to output a higher voltage. Therefore, a voltage conversion circuit is not required to boost the output voltage of multiple power storage devices C1 to a higher voltage for converting the output voltage of multiple power storage devices C1 to the voltage required by load 3, thereby reducing the chance of noise and / or heat generated by the switching operation of the voltage conversion circuit. Therefore, this disclosure enables the provision of a backup power system 1 with the ability to reduce noise and heat generation.

[0024] Furthermore, according to this embodiment, the backup power system 1 is installed in a vehicle 9 that includes a power source 2 and multiple loads 3. That is, the vehicle 9 (mobile body) includes the backup power system 1 and the mobile body 91. The mobile body 91 is equipped with the backup power system 1 and one or more loads 3. In the following description of the embodiments, the case where the backup power system 1 is installed in the vehicle 9 will be described as an example. However, this is only an example and should not be construed as limiting. Alternatively, the backup power system 1 may also be installed in any other suitable type of mobile body (such as an airplane, ship, or train).

[0025] In this embodiment, multiple loads 3 are powered by a backup power system 1 in the event of a power supply failure 2. The multiple loads 3 include a first load 31 and a second load 32. The first load 31 includes an actuator, and the second load 32 serves as a control system for controlling the actuator.

[0026] The first load 31 is an electrical system load 3 including an actuator. The first load 31 is a load 3 that satisfies the following conditions: the load 3 has a power consumption greater than that of the second load 32 (i.e., requires a larger operating current) (hereinafter referred to as the "first condition"), and the load 3 has a minimum guaranteed operating voltage lower than that of the second load 32 (hereinafter referred to as the "second condition"). As used herein, "operating current" refers to the current supplied to allow the load 3 to operate. Additionally, as used herein, "minimum guaranteed operating voltage" refers to the minimum voltage required for the load 3 to operate. That is, the first load 31 is a load that requires a large operating current but whose operating voltage can be reduced to a certain extent (i.e., its operating voltage is allowed to be reduced to a certain extent). Specifically, an example of the first load 31 includes a braking device 31A that generates braking force (in... Figure 1 (marked as "brake") and electronic power steering (EPS) 31B for electronically assisted driver steering.

[0027] The second load 32 is a control system load used to control the actuator. The second load 32 is one of several loads 3 that satisfy the following conditions: the load 3 has a lower power consumption than the first load 31 (i.e., requires a smaller operating current), and the load 3 has a higher minimum guaranteed operating voltage than the first load 31. In other words, the second load 32 is a load that requires a smaller operating current but a relatively higher operating voltage (i.e., does not allow for voltage reduction). Specifically, examples of the second load 32 include an electronic control unit (ECU) 32A for braking (i.e., for controlling braking device 31A), an ECU 32B for controlling the electronic power steering system 31B, and an ECU 32C for controlling the advanced driver assistance system (ADAS). Note that these are merely examples of the first load 31 and the second load 32 and should not be construed as limiting.

[0028] (1.1) Detailed description of the backup power system

[0029] As described above, the backup power system 1 includes multiple power storage devices C1 and a switching unit 12. Additionally, as... Figure 1As shown, the backup power system 1 supplies the output power of power supply 2 to multiple loads 3 when power supply 2 is not faulty, and supplies the output power of multiple power storage devices C1 to the multiple loads 3 instead of the output power of power supply 2 if power supply 2 fails. That is, the backup power system 1 has a power supply path 5 through which the output power of power supply 2 is supplied to multiple loads 3 when power supply 2 is not faulty, and through which the output power of multiple power storage devices C1 is supplied to multiple loads 3 if power supply 2 fails. The backup power system 1 also includes a main switch 10, a voltage detection circuit 11, a step-down power supply circuit 13 for charging, a voltage conversion circuit 14, a switch 15, a control circuit 16, and a controller 17.

[0030] Next, each of these components of the backup power system 1 will be described in detail.

[0031] (1.1.1) Power supply path

[0032] Power supply path 5 is an electrical path that supplies the output power of power supply 2 to multiple loads 3 and multiple power storage devices C1, and also supplies the output power of multiple power storage devices C1 to multiple loads 3. Power supply path 5 includes a first power supply path 51, a second power supply path 52, a third power supply path 53, and a fourth power supply path 54.

[0033] The first power supply path 51 is a power supply path that supplies the output power of power source 2 to multiple loads 3 (e.g., Figure 1 (As indicated by arrow F1 in the diagram). That is, the backup power system 1 includes a power supply path 5 (first power supply path 51) for supplying power from the power source 2 to one or more loads 3 (e.g., multiple loads 3 in this embodiment). The first power supply path 51 includes a main power path 51a and multiple branch paths 51b branching from the main power path 51a. The main power path 51a is connected to the output unit of the power source 2. The multiple branch paths 51b are associated with each of the multiple loads 3. The multiple branch paths 51b branch from the main power path 51a at multiple different points and connect to their associated loads 3.

[0034] Second power supply path 52 (e.g.) Figure 1 (as shown by arrow F2 in the image) and the third power supply path 53 (as shown in the image) Figure 1Arrow F3 indicates a backup power supply path through which the output power of multiple power storage devices C1 is supplied to multiple loads 3. In this case, the multiple (e.g., two in this embodiment) power storage devices C1 include a first power storage device C11 with a low potential in a second state (where the two power storage devices C1 are connected in series with each other), and a second power storage device C12 with a high potential in the second state. The second power supply path 52 is the main power supply path for supplying power to the loads 3 from both the two power storage devices C1 connected in series in the event of a power supply failure 2. The second power supply path 52 is an electrical path that supplies the output voltage of the two power storage devices C1 to the loads 3 via the voltage conversion circuit 14. The third power supply path 53 is a bypass for supplying power to one or more loads 3 from the second power storage device C12 with the low potential. The third power supply path 53 (bypass) is an electrical path for supplying the output voltage of the second power storage device C12 to the loads 3 without via the voltage conversion circuit 14.

[0035] The fourth power supply path 54 is an electrical path that supplies the output power of the power source 2 to the power storage device C1. The fourth power supply path 54 includes a first charging path 541 (e.g., for supplying the output power of the power source 2 to the first power storage device C11) for charging the first charging device C11. Figure 1 (as shown by arrow F41 in the image), and a second charging path 542 for supplying output power from power source 2 to the second power storage device C12 .... Figure 1 (As indicated by arrow F42 in the diagram). The step-down power supply circuit 13 is inserted into the fourth power supply path 54. That is, the backup power system 1 also includes a step-down power supply circuit 13 for charging multiple power storage devices C1 using power supplied from the power source 2. The step-down power supply circuit 13 includes a first step-down power supply circuit 131 inserted into the first charging path 541 and a second step-down power supply circuit 132 inserted into the second charging path 542.

[0036] (1.J.2) Main switch

[0037] The main switch 10 is inserted into the main power path 51a of the first power supply path 51. The main switch 10 is connected between the power supply 2 and the branch node between the first power supply path 51 and the fourth power supply path 54. In addition, the main switch 10 is connected between the power supply 2 and the node where the second power supply path 52 and the third power supply path 53 merge with the first power supply path 51.

[0038] The main switch 10 includes, for example, two switching elements Q1 and Q2 inserted in series in the main electrical path 51a. For example, the switching elements Q1 and Q2 can be semiconductor switches (such as p-channel metal-oxide-semiconductor field-effect transistors (MOSFETs)). These switching elements Q1 and Q2 have drains electrically connected to each other and gates also electrically connected to each other, and are capable of switching from a state where current flows bidirectionally to a state where current is cut off, and vice versa.

[0039] These switching elements Q1 and Q2 turn on and off in response to a power failure signal supplied from the voltage detection circuit 11. Turning on the switching elements Q1 and Q2 allows power to be supplied from the power source 2 to the load 3 through the first power supply path 51, and also allows power to be supplied from the power source 2 to the power storage device C1 through the fourth power supply path 54. Turning off the switching elements Q1 and Q2 disconnects the first power supply path 51 and the fourth power supply path 54.

[0040] (1.1.3) Voltage detection circuit

[0041] The voltage detection circuit 11 monitors the output voltage of the power supply 2 (e.g., 12.5V under normal conditions). When the output voltage of the power supply 2 is found to be equal to or greater than a predetermined threshold (e.g., 9V), the voltage detection circuit 11 determines that the power supply 2 is not faulty. On the other hand, when the output voltage of the power supply 2 is found to be less than the threshold, the voltage detection circuit 11 determines that the power supply 2 is faulty and outputs a power fault signal indicating that a fault has been detected in the power supply 2.

[0042] Please note that the above thresholds are merely examples and can be appropriately changed, for example, based on the output voltage of power supply 2 or the minimum guaranteed operating voltage of load 3.

[0043] (1.1.4) Power storage devices

[0044] Power storage device C1 (i.e., first power storage device C11 and second power storage device C12) is provided as a backup power source (i.e., auxiliary or standby power source) for power source 2. In other words, power storage device C1 is a power source that can supply power to multiple loads 3 in the event of a failure of power source 2. Power storage device C1 can be, for example, an electric double-layer capacitor (EDLC), which can be charged and discharged rapidly. Each power storage device C1 can be composed of two or more power storage devices (such as EDLCs) connected in parallel, in series, or in both parallel and series. That is, each power storage device C1 can be implemented as a parallel or series circuit of two or more power storage devices or combinations thereof.

[0045] (1.1.5) Step-down power supply circuit

[0046] The step-down power supply circuit 13 includes a first step-down power supply circuit 131 and a second step-down power supply circuit 132. A first power storage device C11 is connected between the output terminal of the first step-down power supply circuit 131 and the reference potential of the backup power system 1. A second power storage device C12 and the switching element Q4 of the switching unit 12 are connected in series between the output terminal of the second step-down power supply circuit 132 and the reference potential. The first step-down power supply circuit 131 is configured for a first charging path 541. The second step-down power supply circuit 132 is configured for a second charging path 542. The first step-down power supply circuit 131 and the second step-down power supply circuit 132 have the same circuit configuration. Therefore, the following description will focus on the first step-down power supply circuit 131, while the description of the second step-down power supply circuit 132 will be omitted.

[0047] The first buck power supply circuit 131 is a constant voltage circuit used to charge the first power storage device C11 by reducing the output voltage of the power supply 2 (e.g., a first voltage of 12.5V) to a constant voltage (e.g., a second voltage of 12V), maintaining this constant voltage, and outputting this constant voltage to the first power storage device C11. The first buck power supply circuit 131 may be, for example, a voltage regulator circuit including a series circuit of a switching element Q7 and a resistor R2 inserted into the first charging path 541, an amplifier A2, and a switching element Q8. For example, the switching elements Q7 and Q8 may be semiconductor switches. In this embodiment, the switching element Q7 may be, for example, a p-channel MOSFET. The switching element Q8 may be, for example, an NPN transistor and connected between the control terminal of the switching element Q7 and a reference potential. The resistor R2 is used to detect the charging current flowing through the first power storage device C11. The voltage across the resistor R2 is supplied to the amplifier A2. The output terminal of the amplifier A2 is connected to the control terminal of the switching element Q8. The first step-down power supply circuit 131 is configured to adjust the current used to charge the first power storage device C11 as the voltage across resistor R2 increases. This results in the voltage of the first power storage device C11 when fully charged being lower than the output voltage of power supply 2. Note that... Figure 1 The circuit configuration of the first step-down power supply circuit 131 shown is merely an example and can be modified appropriately.

[0048] (1.1.6) Switching Unit

[0049] The switching unit 12 switches the electrical connection between the first power storage device C11 and the second power storage device C12 to a first state in which the first power storage device C11 and the second power storage device C12 are connected in parallel with the power supply 2, or to a second state in which the first power storage device C11 and the second power storage device C12 are connected in series with each other.

[0050] The switching unit 12 includes switching elements Q3, Q4 and inverter 121.

[0051] For example, the switching element Q3 can be a semiconductor switching element (such as a MOSFET). The switching element Q3 is connected between the high-potential terminal of the first power storage device C11 and the low-potential terminal of the second power storage device C12. The output signal of the inverter 121 (i.e., the inverted signal of the output signal of the voltage detection circuit 11) is supplied to the control terminal of the switching element Q3.

[0052] For example, the switching element Q4 can be a semiconductor switching element (such as a MOSFET). The switching element Q4 is connected between the low-potential terminal of the second power storage device C12 and the reference potential. The output signal of the voltage detection circuit 11 is supplied to the control terminal of the switching element Q3.

[0053] Therefore, when the voltage detection circuit 11 does not output a power fault signal, switching element Q3 is open and switching element Q4 is open, thereby switching the electrical connection between the first power storage device C11 and the second power storage device C12 to a first state in which the first power storage device C11 and the second power storage device C12 are connected in parallel with the power supply 2. In the first state, the first power storage device C11 and the second power storage device C12, which are connected in parallel with the power supply 2, are charged using the power supplied from the power supply 2. The first power storage device C11 and the second power storage device C12 are connected in parallel with the power supply 2, and therefore, both are charged to approximately 12V.

[0054] On the other hand, when the voltage detection circuit 11 outputs a power fault signal, switching element Q3 is turned on and switching element Q4 is turned off, thereby switching the electrical connection between the first power storage device C11 and the second power storage device C12 to a second state in which the first power storage device C11 and the second power storage device C12 are connected in series. In the second state, the sum of the voltages of the first power storage device C11 and the second power storage device C12 connected in series is output (i.e., a voltage of approximately 24V).

[0055] Please note that this circuit configuration of switching unit 12 is merely an example and should not be construed as limiting. Rather, the circuit configuration of switching unit 12 can be modified appropriately, as long as the electrical connection between the first power storage device C11 and the second power storage device C12 can be switched to either the first or the second state.

[0056] (1.1.7) Voltage conversion circuit

[0057] The voltage conversion circuit 14 is a constant voltage circuit used to convert the output voltage of the first power storage device C11 and the second power storage device C12 connected in series to a constant voltage, maintain the constant voltage, and output the maintained constant voltage. The voltage conversion circuit 14 is provided for the second power supply path 52. That is, in the event of a power supply failure (i.e., during discharge), the voltage conversion circuit 14 converts the output voltage of the multiple power storage devices C1 connected in series to an output voltage adapted to one or more loads 3.

[0058] The voltage conversion circuit 14 can be, for example, a boost DC / DC converter. The voltage conversion circuit 14 includes switching elements Q9 and Q10, a Zener diode ZD1, an inductor L1, a diode D3, a capacitor C2, and a control unit 141. For example, switching elements Q9 and Q10 can be semiconductor switching elements (such as MOSFETs). Switching element Q9 and Zener diode ZD1 are connected in series between the high-potential terminal of the second power storage device C12 and a reference potential. Inductor L1 and switching element Q10 are connected in series between the two terminals of Zener diode ZD1. Diode D3 and capacitor C2 are connected in series between the two terminals of switching element Q10.

[0059] Control unit 141 controls the on / off state of switching elements Q9 and Q10.

[0060] When no output command is received from the control circuit 16, the control unit 141 controls the switching element Q9 to be in the open state, so that the switching element Q10 stops performing switching operations. In this way, the control unit 141 stops supplying power from the voltage conversion circuit 14 to the load 3.

[0061] On the other hand, upon receiving an output command from the control circuit 16, the control unit 141 controls the switching element Q9 to be in the on state and performs PWM control on the switching element Q10. When the switching element Q9 is on, a voltage is applied to the Zener diode ZD1 via the first power storage device C11 and the second power storage device C12, which are connected in series with each other. Then, the control unit 141 performs PWM control on the switching element Q10, thereby converting the voltage across the Zener diode ZD1 to a predetermined voltage value and outputting that voltage value. The voltage conversion circuit 14 maintains the voltage slightly higher than the minimum guaranteed operating voltage of the load 3 (e.g., 11.5V) and outputs that voltage. This allows the voltage output from the first power storage device C11 and the second power storage device C12 to the load 3 to remain above the minimum guaranteed operating voltage even if the output voltage of the first power storage device C11 and the second power storage device C12, which are connected in series with each other, decreases.

[0062] (1.1.8) Switch

[0063] Switch 15 is inserted into the third power supply path 53 (bypass).

[0064] Switch 15 may include, for example, two switching elements Q11 and Q12 inserted in series in the third power supply path 53. For example, switching elements Q11 and Q12 may be semiconductor switches (such as p-channel MOSFETs). These switching elements Q11 and Q12 have drains electrically connected to each other and gates also electrically connected to each other, and are capable of switching from a state of bidirectional current flow to a state of current cut-off, and vice versa.

[0065] These switching elements Q11 and Q12 are turned on and off in response to a control signal supplied from the control circuit 16. Turning on the switching elements Q1 and Q2 allows power to be supplied to the load 3 from the first power storage device C11 through the third power supply path 53. Turning off the switching elements Q11 and Q12 disconnects the third power supply path 53. If the power supply 2 fails, the switch 15 will remain on until the voltage conversion circuit 14 is activated, and will turn off when the voltage conversion circuit 14 is fully activated.

[0066] (1.1.9) Control Circuit

[0067] The control circuit 16 is implemented as, for example, a microcomputer including a processor and memory. That is, the control circuit 16 is implemented as a computer system including a processor and memory. The computer system performs the functions of the control circuit 16 by causing the processor to execute an appropriate program. This program may be pre-stored in memory. Alternatively, the program may also be downloaded via a telecommunications line such as the Internet, or distributed after being stored on a non-transitory storage medium such as a memory card.

[0068] In response to a power failure signal supplied from the voltage detection circuit 11, the control circuit 16 controls not only the operation of the voltage conversion circuit 14, but also the on / off state of the switch 15. In this embodiment, when a power supply failure occurs, the control circuit 16 activates the voltage conversion circuit 14 and controls the switch 15 to remain on until the voltage conversion circuit 14 is activated, and then disconnects the switch 15 when the voltage conversion circuit 14 is fully activated.

[0069] When the voltage detection circuit 11 does not output a power fault signal, the control circuit 16 controls the switch 15 to be in the open state, so that the voltage conversion circuit 14 stops performing voltage conversion operation. Therefore, when the voltage detection circuit 11 does not output a power fault signal, the second power supply path 52 and the third power supply path 53 are cut off.

[0070] When the voltage detection circuit 11 outputs a power failure signal, the control circuit 16 sends an output command to the voltage conversion circuit 14, thereby activating the voltage conversion circuit 14. Upon receiving the output command, the control unit 141 of the voltage conversion circuit 14 turns on the switching element Q9 and begins to execute PWM control on the switching element Q10.

[0071] Furthermore, until a predetermined time (e.g., 100 milliseconds (ms)) has elapsed since the control circuit 16 receives a power failure signal from the voltage detection circuit 11, the control circuit 16 keeps switch 15 on to allow power to be supplied to the load 3 from the first power storage device C11 with a low potential through the third power supply path 53. In this case, the predetermined time is set slightly longer than the time it takes for the voltage conversion circuit 14 to be ready to output a voltage equal to or higher than the minimum guaranteed operating voltage (i.e., to fully activate the voltage conversion circuit 14) from the moment it is activated. This allows power to be supplied to the load 3 from the first power storage device C11 with a low potential through the third power supply path 53 when the output voltage of the voltage conversion circuit 14 is lower than the minimum guaranteed operating voltage. Thereafter, when the predetermined time has elapsed since the control circuit 16 receives the power failure signal from the voltage detection circuit 11, the control circuit 16 opens switch 15, disconnects the third power supply path 53, and has power supplied from the voltage conversion circuit 14 to the load 3.

[0072] (1.1.10) Controller

[0073] The controller 17 is implemented as, for example, a microcomputer including a processor and memory. That is, the controller 17 is implemented as a computer system including a processor and memory. The computer system performs the functions of the controller 17 by causing the processor to execute an appropriate program. This program may be pre-stored in memory. Alternatively, the program may be downloaded via a telecommunications line such as the Internet, or distributed after being stored on a non-transitory storage medium such as a memory card.

[0074] The controller 17 performs the function of the selection unit 171, which selects any one of the multiple loads 3 as the target load to be powered (hereinafter simply referred to as "target load 3") based on the usage status of the target device (e.g., vehicle 9 in this embodiment) equipped with multiple loads 3. The controller 17 receives notification information indicating the usage status of vehicle 9 from ECU 4 of vehicle 9. The selection unit 171 selects target load 3 based on the notification information provided by ECU 4. The backup power system 1 according to this embodiment also includes multiple switches Q20-Q24 for selectively powering the multiple loads 3. These switches Q20-Q24 are respectively inserted into branch paths 51b leading to braking device 31A, branch paths 51b leading to electronic power steering system 31B, branch paths 51b leading to ECU 32A for braking, branch paths 51b leading to ECU 32B for EPS, and branch paths 51b leading to ECU 32C for ADAS. For example, each of these switches Q20-Q24 can be a semiconductor switch (such as a p-channel MOSFET). Under the control of controller 17, turning these switches Q20-Q24 on or off makes the branch path 51b, where switches Q20-Q24 are located, conductive or non-conductive. This allows for the selective supply or disconnection of power from the power storage device C1 to the load 3 connected to the branch path 51b.

[0075] When power supply 2 is not faulty, controller 17 turns on these switches Q20-Q24 to allow power to be supplied from power supply 2 to all loads 3.

[0076] In the event of a power supply failure in power supply 2, selection unit 171 selects target load 3 based on notification information provided by ECU 4. Then, controller 17 turns on only the switches in switches Q20-Q24 associated with target load 3 to allow power to be supplied from power storage device C1 only to target load 3.

[0077] In this embodiment, the selection unit 171 can select the target load 3 according to the usage status of the vehicle 9, for example, in the following manner: If the vehicle 9 is driving autonomously when the power supply 2 fails, the selection unit 171 selects all loads 3 as target loads, and the controller 17 controls all switches Q20-Q24 to be in the on state. This allows power to be supplied from the power storage device C1 to all loads 3. Therefore, if the vehicle 9 is driving autonomously when the power supply 2 fails, power is supplied from the power storage device C1 to all loads 3 participating in autonomous driving.

[0078] On the other hand, when power supply 2 fails, unless vehicle 9 is operating autonomously, controller 17 controls switch Q20 to be on and switches Q21-Q24 to be off. This allows power to be cut off from the power storage device C1 to the load 3 connected to switches Q21-Q24. Therefore, power is supplied from the power storage device C1 to loads that participate in braking vehicle 9 and require driver intervention (such as braking device 31A). On the other hand, power is not supplied from the power storage device C1 to other loads that do not participate in braking vehicle 9 and do not require driver intervention (such as the electronic power steering system and its ECU, and the braking device ECU).

[0079] (1.2) Description of the operation

[0080] Next, we will refer to Figures 1 to 7 This section primarily describes how backup power system 1 operates.

[0081] (1.2.1) When the power supply is working normally

[0082] When power supply 2 is not faulty, voltage detection circuit 11 does not output a power fault signal. Therefore, main switch 10 is turned on, and control circuit 16 controls switch 15 to be in the off state to disable voltage conversion circuit 14. Thus, the output power of power supply 2 is supplied to multiple loads 3 (i.e., first load 31 and second load 31) through first power supply path 51 (specifically, main power path 51a and multiple branch paths 51b).

[0083] Furthermore, when power supply 2 is not faulty, switching element Q3 of switching unit 12 is open, and its switching element Q4 is open, thereby connecting the first power storage device C11 and the second power storage device C12 in parallel with power supply 2. Therefore, the first step-down power supply circuit 131 and the second step-down power supply circuit 132 charge the first power storage device C11 and the second power storage device C12, while simultaneously reducing the output voltage of power supply 2. Figure 3 In the diagram, arrows F21 and F22 indicate the current path in this scenario. It can be seen that during charging, multiple power storage devices C1 are connected in parallel with power supply 2 and charged by buck power supply circuit 13. Consequently, the voltage of the fully charged power storage devices C1 becomes equal to or less than the output voltage of power supply 2. At this time, the first buck power supply circuit 131 and the second buck power supply circuit 132, which charge the first power storage device C11 and the second power storage device C12 respectively, do not perform any switching operations, thereby reducing the heat and noise associated with switching operations.

[0084] (1.2.2) When a power supply failure occurs

[0085] When power supply 2 fails and voltage detection circuit 11 outputs a power failure signal, main switch 10 is opened, and the first power supply path 51 and the fourth power supply path 54 are disconnected. Additionally, when voltage detection circuit 11 outputs a power failure signal, switching element Q3 of switching unit 12 is turned on, and its switching element Q4 is turned off, thereby connecting the first power storage device C11 and the second power storage device C12 in series. Simultaneously, upon receiving a power failure signal from voltage detection circuit 11, control circuit 16 outputs an activation command to control unit 141 of voltage conversion circuit 14 to activate voltage conversion circuit 14. In this case, it takes some time for voltage conversion circuit 14 to output a voltage equal to or higher than the minimum guaranteed operating voltage from the start of its voltage conversion operation (i.e., it takes some time to fully activate voltage conversion circuit 14). Therefore, control circuit 16 controls switch 15 to remain on until a predetermined time has elapsed since the moment the power failure signal was received. If switch 15 is on, the third power supply path 53 becomes conductive. This allows power to be supplied to the load 3 from the first power storage device C11, which has a low potential, via the third power supply path 53. At this time, current flows from the first power storage device C11 along... Figure 4 The path indicated by arrow F23 flows to multiple loads 3. The first power storage device C11 is charged to a voltage equal to or higher than the minimum guaranteed operating voltage. This allows the loads 3 to operate using the power supplied from the first power storage device C11 until the voltage conversion circuit 14 is fully activated, thereby reducing the chance of the output voltage supply to the loads 3 being cut off.

[0086] Subsequently, when a predetermined time has elapsed since the power supply 2 failed, control circuit 16 disconnects switch 15, and voltage conversion circuit 14 reduces the output voltage of the first power storage device C11 and the second power storage device C12, supplying the generated output voltage to load 3. At this time, current flows from voltage conversion circuit 14 along... Figure 4 The path indicated by arrow F24 flows to load 3. In this case, if power supply 2 fails, the first power storage device C11 and the second power storage device C12 are connected in series, causing the output voltage of the first power storage device C11 and the second power storage device C12 to be higher than the minimum guaranteed operating voltage of load 3. This allows the voltage conversion circuit 14 to supply the load 3 with the output voltage generated by reducing the output voltage of the first power storage device C11 and the second power storage device C12. This makes it possible to reduce the amount of current flowing through the primary circuit portion of the voltage conversion circuit 14, thereby reducing the heat and noise generated by the switching element Q10 when the voltage conversion circuit 14 performs switching operations.

[0087] In this configuration, a diode that allows current to flow in the direction supplying power to one or more loads 3 is inserted into the third power supply path 53 (bypass). In this embodiment, the parasitic diode of the MOSFET used as the switching element Q12 serves as the diode that allows current to flow in the direction supplying power to load 3. The parasitic diode of the MOSFET used as the switching element Q12 essentially prevents current from flowing in the opposite direction to the direction supplying power from the first power storage device C11 to the load 3. This reduces the chance that the power that should be supplied to load 3 will flow through the first power storage device C11, resulting in insufficient power supply to load 3. Alternatively, in this embodiment, another diode that allows current to flow in the direction supplying power to load 3 can be connected separately from the parasitic diode of the MOSFET used as the switching element Q12 to the third power supply path 53. This essentially prevents current from flowing in the opposite direction.

[0088] Please note that in the first power supply path 51, diode D4 is connected between branch path 51b connected to the first load 31 and branch path 51b connected to the second load 32. Therefore, diode D4 can prevent the power supplied to the second load 32 from flowing back into the first load 31 through the first power supply path 51 when power is supplied to the second load 32 from the power storage device C1 via the second power supply path 52 or the third power supply path 53.

[0089] (1.2.3) Operation of selecting target load

[0090] As described above, in the backup power system 1 according to this embodiment, the selection unit 171 of the controller 17 selects the target load 3 based on the notification information provided by the ECU 4 of the vehicle 9.

[0091] For example, if a power supply 2 fails in vehicle 9 traveling at a predetermined speed (e.g., 60 km / h), selection unit 171 turns on switch Q20 and turns off switches Q21-Q24 to supply power from power storage device C1 only to braking device 31A (see reference). Figure 6 Even so, from the moment power supply 2 fails until voltage conversion circuit 14 is fully activated, power is supplied via the third power supply path 53 (bypass) (i.e., along...). Figure 6 Power is supplied from the first power storage device C11 to the braking device 31A via the path indicated by arrow F25 in the diagram. Then, when the voltage conversion circuit 14 is fully activated, power is supplied via the second power supply path 52 (i.e., along...). Figure 6 The path indicated by arrow F26 in the diagram supplies power from the voltage conversion circuit 14 to the braking device 31A.

[0092] In this embodiment, a constant voltage equal to or higher than the minimum guaranteed operating voltage is continuously supplied to the load 3 for a certain period of time (e.g., 6 seconds) after the power supply 2 fails. This certain period of time can be, for example, longer than the time it takes for the vehicle 9 traveling at a predetermined speed (e.g., 60 km / h) to come to a safe stop in the same lane. This allows the driver to safely stop the vehicle 9 even if the power supply 2 fails while the vehicle 9 is traveling at the predetermined speed.

[0093] Furthermore, the backup power system 1 also allows power to be supplied to the braking device 31A via the second power supply path 52 from the voltage conversion circuit 14 when the vehicle 9's power supply 2 is operating normally (i.e., when performing a so-called "remote parking"), for example, when the vehicle 9 is parked remotely. In other words, the vehicle 9 can only be remotely parked when the power supply 2 is operating normally and power can be supplied to the braking device 31A from the backup power system 1. That is to say, as Figure 7 As shown, vehicle 9 can only be remotely parked when both the path for power supply from power source 2 to braking device 31A (i.e., the path indicated by arrow F27) and the path for power supply from voltage conversion circuit 14 to braking device 31A (i.e., the path indicated by arrow F28) are ensured. In this case, the selection unit 171 of controller 17, based on the notification information for remote parking provided by ECU 4, allows power to be supplied only to braking device 31A from power storage device C1 by turning on switch Q20 and turning off switches Q21-Q24. Then, controller 17 controls switching unit 12 to switch the electrical connection to a second state where the first power storage device C11 and the second power storage device C12 are connected in series, outputs a control signal to control circuit 16 to control switch 15 to be in the off state, and activates voltage conversion circuit 14. This allows power to be supplied to braking device 31A from voltage conversion circuit 14, thereby allowing vehicle 9 to be remotely parked.

[0094] If power supply 2 fails while vehicle 9 is being remotely parked, then start (along...) Figure 7 The path indicated by arrow F28 in the diagram supplies power from voltage conversion circuit 14 to braking device 31A, thereby allowing the driver to safely stop vehicle 9.

[0095] Please note that if, during remote parking of vehicle 9, the voltage conversion circuit 14 is not activated until a power supply failure occurs, controller 17 can control switch 15 to be in the ON state to supply power from the first power storage device C11 to the braking device 31A until the voltage conversion circuit 14 is fully activated. In this case, when the voltage conversion circuit 14 is fully activated, controller 17 can control switch 15 to be in the OFF state to supply power from the voltage conversion circuit 14 to the braking device 31A.

[0096] Please note that even if vehicle 9 is not used for a predetermined period (e.g., 75 days), the backup power system 1 still allows vehicle 9 to be remotely parked. The power storage device C1 discharges when not in use for an extended period. However, its charging and discharging performance is configured so that the braking device 31A can operate even after the predetermined period has elapsed.

[0097] (2) Variation

[0098] Next, variations of the example embodiments will be listed one by one. Note that the variations described below can be appropriately combined. The description of the variations below will focus on the differences from the example embodiments described above. Any constituent element of a variation having the same function as the corresponding part of the example embodiments described above will be indicated by the same reference numerals as the corresponding part, and its description will be omitted herein.

[0099] In the above example embodiments, each power storage device C1 can be a secondary battery such as a lithium-ion capacitor (LIC) or a lithium-ion battery (LIB). In a lithium-ion capacitor, its cathode can be made of the same material as an EDLC (such as activated carbon), and its anode can be made of the same material as a LIB (e.g., a carbon material, such as graphite).

[0100] Furthermore, the power storage device C1 is not necessarily an EDLC; it can also be an electrochemical device with the configuration described below. As used herein, an "electrochemical device" includes a cathode element, an anode element, and a non-aqueous electrolyte solution. The positive electrode element includes a positive current collector and a positive electrode material layer supported by the positive current collector and containing a positive electrode active material. The positive electrode material layer contains a conductive polymer used as the positive electrode active material for doping and dedoping negative ions (dopants). The negative electrode element includes a negative electrode material layer containing a negative electrode active material. The negative electrode active material can be, for example, a material that promotes redox reactions involving lithium ion adsorption and release. Specifically, examples of negative electrode active materials include carbon materials, metal compounds, alloys, and ceramics. The non-aqueous electrolyte solution can have, for example, lithium-ion conductivity. This type of non-aqueous electrolyte solution includes lithium salts and non-aqueous solutions of dissolved lithium salts. For example, an electrochemical device with this configuration has a higher energy density than an electric double-layer capacitor.

[0101] Furthermore, in the above embodiment, the voltage conversion circuit 14 includes a boost DC / DC converter. However, the circuit configuration of the voltage conversion circuit 14 can be appropriately modified, as long as the voltage conversion circuit 14 can convert the input voltage to a voltage value suitable for the load 3. For example, the voltage conversion circuit 14 may include a boost / buck DC / DC converter.

[0102] Furthermore, in the above example embodiment, the power storage device C1 is charged by the output of the buck power supply circuit 13. However, the circuit for supplying charging current to the power storage device C1 is not necessarily the buck power supply circuit 13. The circuit for supplying charging current to the power storage device C1 is preferably a circuit other than a switching power supply circuit, and may be a series voltage regulator circuit, or include a circuit that connects a current-limiting resistor between the power supply 2 and the power storage device C1.

[0103] Furthermore, in the above example embodiment, each of the first load 31 and the second load 32 is a group of loads (i.e., including multiple loads). However, this is merely an example and should not be construed as limiting. Alternatively, each of the first load 31 and the second load 32 may be a single load. Still alternatively, at least one of the first load 31 or the second load 32 may be a group of loads.

[0104] Furthermore, in the above example embodiment, the first load 31 satisfies both the first and second conditions compared to the second load 32. However, this is merely an example and should not be construed as limiting. Alternatively, the first load 31 may satisfy at least one of the first or second conditions. Note that the first condition is that the load has relatively high power consumption (i.e., requires a relatively high operating current). The second condition is that the load requires a relatively low minimum guaranteed operating voltage.

[0105] Furthermore, in the above example embodiment, the target device including multiple loads 3 is a vehicle 9 (mobile body). However, the target device is not necessarily a vehicle 9 (mobile body); for example, it could be electrical equipment used in a facility.

[0106] (Summary)

[0107] As can be seen from the above description, the backup power system (1) according to the first aspect supplies power to one or more loads (3) in the event of a failure of the power supply (2). The backup power system (1) includes multiple power storage devices (C1) and a switching unit (12). The multiple power storage devices (C1) are charged by the power supply (2). The switching unit (12) switches the electrical connection between the multiple power storage devices (C1) to a first state in which the multiple power storage devices (C1) are connected in parallel with the power supply (2), or to a second state in which the multiple power storage devices (C1) are connected in series with each other. The switching unit (12) switches the electrical connection to the first state when the multiple power storage devices (C1) are being charged, and switches the electrical connection to the second state when the power supply (2) fails.

[0108] According to this aspect, during charging, multiple power storage devices (C1) are connected in parallel with the power supply (2). Compared to the case where multiple power storage devices (C1) are connected in series, this allows the multiple power storage devices (C1) to be charged at a lower voltage. Therefore, a charging circuit is not required to boost the voltage of the power supply (2) to a higher voltage for charging the multiple power storage devices (C1), thus reducing the chance of noise and / or heat generated by the switching operation of the charging circuit. In addition, when the power supply (2) fails, the multiple power storage devices (C1) are connected in series with each other. Compared to the case where multiple power storage devices (C1) are connected in parallel, this allows the multiple power storage devices (C1) to output a higher voltage. Therefore, a voltage conversion circuit is not required to convert the output voltage of the multiple power storage devices (C1) to the voltage required by the load (3), thus reducing the chance of noise and / or heat generated by the switching operation of the voltage conversion circuit. Therefore, this disclosure enables the provision of a backup power system (1) with the ability to reduce noise to be generated and a backup power system (1) with the ability to reduce heat to be generated.

[0109] In the backup power system (1) according to the second aspect which can be implemented in conjunction with the first aspect, the plurality of power storage devices (C1) include: a first power storage device (C11) having a low potential in the second state; and a second power storage device (C12) having a high potential in the second state. The backup power system (1) also includes a bypass (53) through which power is supplied from the first power storage device (C11) to one or more loads (3) in the event of a failure of the power supply (2).

[0110] This aspect enables the supply of power from the first power storage device (C11) to one or more loads (3) via a bypass (53).

[0111] In the backup power system (1) according to the third aspect which can be implemented in conjunction with the second aspect, a diode is inserted into the bypass (53). The diode allows current to flow in the direction of power supply to one or more loads (3).

[0112] This aspect makes it possible to reduce the chance of current flowing through the bypass (53) in the opposite direction to the power supply direction.

[0113] The backup power system (1), which can be implemented in conjunction with the second or third aspect, also includes a voltage conversion circuit (14) and a switch (15). In the event of a power supply (2) failure, the voltage conversion circuit (14) converts the output voltage of multiple power storage devices (C1) connected in series to an output voltage adapted to one or more loads (3). The switch (15) is inserted into a bypass (53). In the event of a power supply (2) failure, the switch (15) remains on until the voltage conversion circuit (14) is activated, and disconnects when the voltage conversion circuit (14) is fully activated.

[0114] According to this, power is continuously supplied to one or more loads (3) via bypass (53) until the voltage conversion circuit (14) is activated. This reduces the chance of power supply to one or more loads (3) being cut off.

[0115] The backup power system (1) according to the fifth aspect, which can be implemented in conjunction with the fourth aspect, also includes a control circuit (16). When the power supply (2) fails, the control circuit (16) starts to activate the voltage conversion circuit (14) and controls the switch (15) to keep the switch (15) on until the voltage conversion circuit (14) is activated, and opens the switch (15) when the voltage conversion circuit (14) is fully activated.

[0116] According to this, power is continuously supplied to one or more loads (3) via bypass (53) until the voltage conversion circuit (14) is activated. This reduces the chance of power supply to one or more loads (3) being cut off.

[0117] The backup power system (1) according to the sixth aspect, which can be implemented in combination with any of the first to fifth aspects, also includes a step-down power supply circuit (13). The step-down power supply circuit (13) uses power supplied from the power source (2) to charge multiple power storage devices (C1).

[0118] Accordingly, the step-down power supply circuit (13) charges multiple power storage devices (C1). This reduces the chance of noise and / or heat generation by the switching power supply compared to charging multiple power storage devices (C1) using voltage boosted by the switching power supply.

[0119] In the backup power system (1) according to the seventh aspect which can be implemented in combination with any of the first to sixth aspects, one or more loads (3) include multiple loads (3). The backup power system (1) also includes a selection unit (171). The selection unit (171) selects any one of the multiple loads (3) as the target load to be powered based on the usage status of the target device (9) on which the multiple loads (3) are provided.

[0120] According to this, power is supplied only to the load (3) selected based on the usage status of the target device (9). This allows for a longer supply time compared to supplying power to all multiple loads (3).

[0121] In the backup power system (1) according to the eighth aspect which can be implemented in conjunction with the seventh aspect, the plurality of loads (3) include: a first load (31) including an actuator; and a second load (32) serving as a control system for controlling the actuator.

[0122] This aspect enables the selection of a target load (3) from a first load (31) and a second load (32) based on the usage status of the target device (9).

[0123] The backup power system (1) according to the ninth aspect, which can be implemented in combination with any of the first to eighth aspects, also includes a power supply path (51) through which power is supplied from the power source (2) to one or more loads (3).

[0124] This aspect enables power to be supplied from the power source (2) to one or more loads (3) via the power path (51).

[0125] The mobile body (9) according to the tenth aspect includes a backup power system (1) according to any one of the first to ninth aspects and a mobile body (91). The mobile body (91) is equipped with the backup power system (1) and one or more loads (3).

[0126] This aspect enables the ability to reduce the noise generated by the moving body (9).

[0127] Please note that these are not the only aspects of this disclosure, and various configurations (including variations) of the backup power system (1) according to the above example embodiments can also be implemented as a method for controlling the backup power system (1), a (computer) program, or a non-transitory storage medium storing a program thereon.

[0128] Please note that the constituent elements according to the second to eighth aspects are not essential constituent elements of the backup power system (1), but can be appropriately omitted.

[0129] List of reference numerals

[0130] 1. Backup power system

[0131] 2 Power Supply

[0132] 3. Load

[0133] 9. Vehicles (mobile objects, target equipment)

[0134] 12 Switching Units

[0135] 13. Step-down power supply circuit

[0136] 14 Voltage Conversion Circuit

[0137] 15 Switches

[0138] 16 Control Circuit

[0139] 31 First Load

[0140] 32 Second Load

[0141] 51 First power supply path (power supply path)

[0142] 53 Third power supply path (bypass)

[0143] 91. The main body of the moving object

[0144] 171 Selection Unit

[0145] C1 Power storage device

[0146] C11 First Power Storage Device

[0147] C12 Second power storage device.

Claims

1. A backup power system configured to supply power to one or more loads in the event of a power failure, the backup power system comprising: Multiple power storage devices are configured to be charged by the power source; as well as The switching unit is configured to switch the electrical connection between the plurality of power storage devices to a first state in which the plurality of power storage devices are connected in parallel with the power supply, or to a second state in which the plurality of power storage devices are connected in series with each other. The switching unit is configured to switch the electrical connection to the first state when the plurality of power storage devices are being charged, and to switch the electrical connection to the second state when the power supply fails. The plurality of power storage devices includes: a first power storage device configured to have a low potential in the second state; And a second power storage device, configured to have a high potential in the second state, and The backup power system also includes a bypass, through which power is supplied from the first power storage device to the one or more loads in the event of a power failure.

2. The backup power system according to claim 1, wherein, A diode is inserted into the bypass, and the diode is configured to allow current to flow in the direction of power supply to the one or more loads.

3. The backup power system according to claim 1 or 2 further includes: A voltage conversion circuit is configured to, in the event of a power supply failure, convert the output voltage of the plurality of power storage devices connected in series to an output voltage adapted to the one or more loads; as well as The switch is inserted into the bypass, wherein, The switch is configured to remain on until the voltage conversion circuit is activated in the event of a power failure, and to disconnect when the voltage conversion circuit is fully activated.

4. The backup power system of claim 3 further includes a control circuit configured to activate the voltage conversion circuit when the power supply fails, control the switch to remain on until the voltage conversion circuit is activated, and disconnect the switch when the voltage conversion circuit is fully activated.

5. The backup power system according to claim 1 or 2 further includes a step-down power supply circuit configured to charge the plurality of power storage devices using power supplied from the power source.

6. The backup power system according to claim 1 or 2, wherein, The one or more loads include multiple loads, and The backup power system further includes a selection unit, which is configured to select any one of the multiple loads as the target load to be powered, based on the usage status of the target device with the multiple loads.

7. The backup power system according to claim 6, wherein, The plurality of loads include: a first load comprising an actuator; and a second load serving as a control system configured to control the actuator.

8. The backup power system according to claim 1 or 2 further includes a power supply path through which power is supplied from the power source to the one or more loads.

9. A mobile body, comprising: The backup power system according to any one of claims 1 to 8; as well as A mobile body equipped with the backup power system and the one or more loads.

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