Charge-discharge control device

Abstract

Provided is a charge-discharge control device that suppresses a period during which no power is supplied to a load in the event of a power failure related to a power supply section. In the charge-discharge control device (10), a voltage conversion section (30) performs voltage conversion between a second conduction path (42) and a third conduction path (43). A first switch (51) switches between an on state that allows current to flow from a first conduction path (41) to the second conduction path (42) and an off state that cuts off the current. A second switch (52) switches between an on state that allows current to flow from the second conduction path (42) to a second power path (82) and an off state that cuts off the current. An auxiliary charge section (60) switches between a state of supplying power to an electric storage section (12) via a path different from the voltage conversion section (30) on the basis of power supplied via the first conduction path (41) and a state of stopping the supply of power via the path.

Description

Technical Field

[0001] This disclosure relates to a charge and discharge control device. Background Technology

[0002] Patent Document 1 discloses a power supply system for an electronically controlled brake in a vehicle. In the system disclosed in Patent Document 1, the backup power supply includes a first capacitor and a second capacitor. The first capacitor is charged via an alternator when the vehicle's ignition switch is turned on. The second capacitor is connected in parallel with the first capacitor when the vehicle's ignition switch is turned off, and receives a portion of the charge stored in the first capacitor to be charged.

[0003] Existing technical documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2009-234489 Summary of the Invention

[0005] The problem that the invention aims to solve

[0006] When a power system installed in a vehicle or similar device experiences a power failure, such as when it ceases to supply power to the load from the power source (main battery, etc.), it utilizes power from an energy storage unit, which is different from that of the power source, for backup operation. In this backup operation, a voltage converter transforms the voltage input to the voltage conversion unit (such as a DC-DC converter) based on the power from the energy storage unit into the desired output voltage and supplies power to the load.

[0007] However, in such a power supply system, if the voltage converter is activated after a power failure, a certain amount of time is required until the voltage converter operates normally and outputs an appropriate voltage, thus raising concerns about a period of power interruption for the load. Therefore, a structure is desired that can activate the voltage converter as early as possible and ensure its operation is as continuous as possible. However, on the other hand, in such a power supply system, it is also required to charge the battery used in backup operation at a desired time. However, if the operation of the voltage converter must be stopped to charge the battery, then if the aforementioned power failure occurs while the voltage converter is stopped, a period of power interruption for the load will occur.

[0008] This disclosure provides a technique for suppressing periods of power supply failure to the load in the event of a power failure associated with the power supply unit.

[0009] Technical solutions for solving the problem

[0010] As part of this disclosure, a charge / discharge control device controls charging and discharging in a power supply system comprising a power supply unit, an energy storage unit, a first power path, and a second power path. The first power path is a path for supplying power from the power supply unit to a load, and the second power path is a path for supplying power from the energy storage unit to the load.

[0011] The above-mentioned charge and discharge control device has the following features:

[0012] The first conductive path is the path for transmitting power based on the aforementioned power supply unit;

[0013] The second conductive path is sandwiched between the aforementioned second electrical path and the aforementioned first conductive path;

[0014] The third conductive path is electrically connected to the aforementioned energy storage unit;

[0015] The voltage conversion unit performs voltage conversion between the second conductive path and the third conductive path;

[0016] A first switch is disposed between the first conductive path and the second conductive path, and switches between an on state that allows current to flow from the first conductive path to the second conductive path and an off state that cuts off the current.

[0017] A second switch is disposed between the second conductive path and the second electrical path, and switches between an on state that allows current to flow from the second conductive path to the second electrical path and an off state that cuts off the flow; and

[0018] The auxiliary charging unit switches between a supply state, in which power is supplied to the energy storage unit via a different path than that of the voltage conversion unit based on the power supplied through the first conductive path, and a stop state, in which power supply to the energy storage unit is stopped.

[0019] Invention Effects

[0020] The technology disclosed herein can suppress periods during which no power is supplied to the load in the event of a power failure related to the power supply unit. Attached Figure Description

[0021] Figure 1 This is a circuit diagram that schematically illustrates an example of an on-board system including the charge / discharge control device of the first embodiment.

[0022] Figure 2 This means that in Figure 1 An explanatory diagram of the control (first control) when the charging and discharging control device of the first embodiment of the vehicle system is charging the energy storage unit.

[0023] Figure 3 This means that in Figure 1An explanatory diagram of the control (second control) in the case of backup preparation of the charging and discharging control device of the first embodiment in the vehicle system.

[0024] Figure 4 This means that in Figure 1 This diagram illustrates a power failure situation where a power supply interruption occurs from the power supply unit in the second control of the vehicle system.

[0025] Figure 5 This means that in Figure 1 The diagram illustrates the control (third control) of the charging and discharging control device of the first embodiment in the vehicle system when charging the battery while preparing for backup.

[0026] Figure 6 This means that in Figure 1 This diagram illustrates a power failure situation where a power supply interruption occurs from the power supply unit in the third control of the vehicle's onboard system. Detailed Implementation

[0027] [Description of embodiments of this disclosure]

[0028] Hereinafter, embodiments of the present disclosure will be illustrated. Furthermore, the features [1] to [4] illustrated below can be combined arbitrarily in a non-contradictory manner.

[0029] [1] A charge / discharge control device controls charging and discharging in a power supply system comprising a power supply unit, a storage unit, a first power circuit, and a second power circuit, wherein the first power circuit is a path for supplying power from the power supply unit to a load, and the second power circuit is a path for supplying power from the storage unit to the load.

[0030] The above-mentioned charge and discharge control device has the following features:

[0031] The first conductive path is the path for transmitting power based on the aforementioned power supply unit;

[0032] The second conductive path is sandwiched between the aforementioned second electrical path and the aforementioned first conductive path;

[0033] The third conductive path is electrically connected to the aforementioned energy storage unit;

[0034] The voltage conversion unit performs voltage conversion between the second conductive path and the third conductive path;

[0035] A first switch is disposed between the first conductive path and the second conductive path, and switches between an on state that allows current to flow from the first conductive path to the second conductive path and an off state that cuts off the current.

[0036] A second switch is disposed between the second conductive path and the second electrical path, and switches between an on state that allows current to flow from the second conductive path to the second electrical path and an off state that cuts off the flow; and

[0037] The auxiliary charging unit switches between a supply state, in which power is supplied to the energy storage unit via a different path than that of the voltage conversion unit based on the power supplied through the first conductive path, and a stop state, in which power supply to the energy storage unit is stopped.

[0038] The charge / discharge control device described in [1] above can prepare for backup operation by turning the first switch to the open state and the second switch to the on state, and by having the voltage conversion unit apply the output voltage to the second conductive circuit. If the charge / discharge control device prepares for backup operation before a power failure such as an interruption of power supply from the power supply unit via the first power circuit, it can immediately resume power supply to the load immediately after the power failure occurs. Moreover, the charge / discharge control device can also prepare for backup operation and charge the energy storage unit through the auxiliary charging unit. In other words, when the energy storage unit is charging, the charge / discharge control device can prevent the interruption of backup operation preparation from occurring, and can easily prevent the backup operation from being delayed due to a power failure during the preparation interruption. Thus, the charge / discharge control device described in [1] above has a highly advantageous structure in suppressing the situation where power is not supplied to the load in the event of a power failure associated with the power supply unit.

[0039] [2] Based on the charge / discharge control device described in [1] above, it has the following features. The charge / discharge control device of [2] has a control unit. The control unit performs a first control, a second control, and a third control. The first control is to turn on the first switch and to perform the operation of the voltage conversion unit to increase or decrease the voltage applied to the second conductive circuit and apply it to the third conductive circuit. The second control is to turn off the first switch, turn on the second switch, turn the auxiliary charging unit to the stop state, and to perform the operation of the voltage conversion unit to increase or decrease the voltage applied to the third conductive circuit and apply it to the second conductive circuit. The third control is to turn off the first switch, turn on the second switch, turn the auxiliary charging unit to the supply state, and to perform the switching operation of the voltage conversion unit to increase or decrease the voltage applied to the third conductive circuit and apply it to the second conductive circuit.

[0040] The charge / discharge control device described in [2] above performs first control via the control unit, enabling the charging of the energy storage unit using the voltage conversion unit, and performs second control via the control unit, enabling the discharging of the energy storage unit using the voltage conversion unit. In other words, the charge / discharge control device of [2] can switch between charging and discharging the energy storage unit using the voltage conversion unit via first control and second control. Furthermore, when a situation arises during the second control (i.e., while the voltage conversion unit is applying voltage to the second power circuit), and a situation occurs requiring charging of the energy storage unit, the charge / discharge control device of [2] can switch from the second control to the third control. In this case, although the charge / discharge control device continues to perform the "applying voltage to the second power circuit (backup preparation operation)," it can increase the charging voltage of the energy storage unit, thus preventing the interruption of the preparation operation during charging of the energy storage unit.

[0041] [3] Based on the charge / discharge control device described in [2] above, it has the following features. When the power system is in a predetermined voltage drop state where the voltage of the first power circuit is lower than the voltage of the second power circuit, it supplies power to the load via the second power circuit. When it is in a normal state where it is not in the predetermined voltage drop state, it cuts off the power supply to the load via the second power circuit. When the control unit performs the second control, it causes the voltage conversion unit to perform the conversion operation to apply the output voltage of the normal state to the second conductive circuit. When a predetermined condition is met while the second control is being performed, it switches to the third control.

[0042] When the power system using the charge / discharge control device described in [3] reaches a predetermined voltage drop state where the voltage of the first power circuit is lower than that of the second power circuit, power is supplied to the load via the second power circuit. Therefore, if a preparatory operation is performed by applying an appropriate voltage to the second power circuit through the second control, power can be supplied immediately via the second power circuit even if the voltage of the first power circuit drops significantly. Furthermore, when a predetermined condition is met in the state of the second control, the charge / discharge control device described in [3] can continue charging the battery without significantly interrupting the preparatory operation by switching from the second control to the third control. In the third control, if a preparatory operation is performed by applying an appropriate voltage to the second power circuit, power can be supplied immediately via the second power circuit even if the voltage of the first power circuit drops significantly.

[0043] [4] In the charge and discharge control device described in [3] above, the predetermined condition is that the output voltage applied by the energy storage unit to the third conductive circuit reaches a threshold below.

[0044] The charge / discharge control device described in [4] above can continue charging the battery without significantly interrupting the preparation operation when the output voltage of the battery applied to the third conductive circuit drops below a threshold. Therefore, the charge / discharge control device in [4] avoids the situation where the preparation operation continues even when the output voltage of the battery drops below the threshold, thus preventing the battery output voltage from becoming too low during backup operations corresponding to power failure. Furthermore, the charge / discharge control device in [4] prevents significant interruption of the preparation operation as a countermeasure.

[0045] [Details of the embodiments disclosed herein]

[0046] <First Implementation>

[0047] 1. Overview of in-vehicle systems

[0048] exist Figure 1 The image shows vehicle system 2. Figure 1 The vehicle-mounted system 2 mainly includes a vehicle-mounted power supply system 3 and a load 101. The vehicle-mounted power supply system 3 is also referred to as power system 3 in the following description. The vehicle-mounted system 2 is a system that supplies power to the load 101 through the power supply system 3, thereby enabling the load 101 to operate. Figure 1 In this example, load 101 is shown as a load, but other loads can also be set in the vehicle system 2.

[0049] Load 101 is an electrical component mounted on a vehicle. Load 101 operates by receiving power supplied via a common power circuit 80. The type of load 101 is not limited. Various known vehicle components can be used as load 101. Load 101 can have multiple electrical components or can be a single electrical component.

[0050] The power supply system 3 is a system that supplies power to the load 101. The power supply system 3 supplies power to the load 101 by using the power supply unit 91 or the energy storage unit 12 as the power supply source. The power supply system 3 can supply power to the load 101 from the power supply unit 91, and in the event that the power supply from the power supply unit 91 is interrupted due to a fault or other reasons, it can supply power to the load 101 from the energy storage unit 12.

[0051] 2. Overview of the power supply system

[0052] The power system 3 includes: a power supply unit 91, an energy storage unit 12, a charge / discharge control device 10, a first power circuit 81, a second power circuit 82, and a selection unit 70.

[0053] The power supply unit 91 is an on-board power supply capable of supplying power to the load 101. The power supply unit 91 is configured, for example, as a known on-board battery such as a lead-acid battery. The power supply unit 91 may be composed of a battery other than a lead-acid battery, or it may replace the battery, or it may have a power unit other than a battery in addition to the battery. The positive terminal of the power supply unit 91 is electrically connected to the first power circuit 81 by shorting it. The negative terminal of the power supply unit 91 is electrically grounded by shorting it to ground. The power supply unit 91 applies a constant DC voltage to the first power circuit 81. The voltage applied by the power supply unit 91 to the first power circuit 81 may also vary slightly relative to the aforementioned constant value.

[0054] The energy storage unit 12 is a power source that serves as a power supply at least when the power supply from the power source 91 is interrupted. The energy storage unit 12 is constructed, for example, of a known energy storage unit such as an electric double-layer capacitor (EDLC). The energy storage unit 12 may be constructed of a capacitor other than an EDLC, or it may replace a capacitor or include other energy storage units (such as batteries). The positive terminal of the energy storage unit 12 is electrically connected to the third conductive path 43 in a configuration that short-circuits it to the third conductive path 43. The negative terminal of the energy storage unit 12 is electrically grounded in a configuration that short-circuits it to ground. The output voltage of the energy storage unit 12 (the voltage applied to the third conductive path 43 by the energy storage unit 12) may be greater than or less than the output voltage of the power source 91 (the voltage applied to the first power path 81 by the power source 91). In the representative example described below, the output voltage of the power source 91 when fully charged is greater than the output voltage of the voltage conversion unit 30 (the voltage output to the second conductive path 42). The output voltage of the energy storage unit 12 may be higher or lower than the output voltage of the power source 91, and may be variable. In the representative example described below, when the energy storage unit 12 is discharging, the voltage conversion unit 30 can boost or deboost the voltage output by the energy storage unit 12 (the voltage applied to the third conductive circuit 43) to a voltage slightly lower than the output voltage of the power supply unit 91 and output it to the second conductive circuit 42.

[0055] In this specification, unless otherwise specified, voltage refers to voltage relative to ground potential (e.g., 0V), and refers to the potential difference between the voltage and ground potential. For example, the voltage applied to the first power circuit 81 refers to the potential difference between the potential of the first power circuit 81 and the ground potential. The voltage applied to the third conductive circuit 43 refers to the potential difference between the potential of the third conductive circuit 43 and the ground potential.

[0056] The first power path 81 is a path for transmitting power based on the power supply unit 91, and is a path for supplying power based on the power supply unit 91 to the load 101. Figure 1In this example, a voltage that is the same as or approximately the same as the output voltage of the power supply unit 91 is applied to the first power circuit 81. One end of the first power circuit 81 is electrically connected to the positive terminal of the power supply unit 91 by shorting it. The other end of the first power circuit 81 is electrically connected to the anode of the diode 71. The first power circuit 81 is electrically connected to the first conductive circuit 41 by shorting it. A relay and a fuse may also be provided in the first power circuit 81.

[0057] The second power path 82 is a path for transmitting power based on the energy storage unit 12. In the event of a power failure, the second power path 82 functions as a path to supply power based on the energy storage unit 12 to the load 101. One end of the second power path 82 is electrically connected to the other end of the second switch 52, and the other end of the second power path 82 is electrically connected to the anode of the diode 72.

[0058] The selection unit 70 is a circuit that selects whether the power supplied to the load 101 is based on the power from the power supply unit 91 or on the power from the energy storage unit 12. The selection unit 70 includes diodes 71 and 72.

[0059] The anode of diode 71 is electrically connected to the first power circuit 81. A voltage based on the power supply section 91 is applied to the anode of diode 71. Figure 1 In this example, the anode of diode 71 is set to the same potential as the first power circuit 81, and the anode of diode 71 is short-circuited to the positive terminal of the power supply unit 91. The anode of diode 72 is electrically connected to the second power circuit 82. The anode of diode 72 is set to the same potential as the second power circuit 82. The two cathodes of diodes 71 and 72 are electrically connected to the common power circuit 80, and the two cathodes are set to the same potential as the common power circuit 80. The common power circuit 80 is a conductive circuit electrically connected to the load 101. When the potential of the first power circuit 81 is greater than the potential of the second power circuit 82, the selection unit 70 allows current to flow from the first power circuit 81 to the common power circuit 80, and prevents current from flowing from the second power circuit 82 to the common power circuit 80. When the potential of the second power circuit 82 is greater than the potential of the first power circuit 81, the selection unit 70 allows current to flow from the second power circuit 82 to the common power circuit 80, and prevents current from flowing from the first power circuit 81 to the common power circuit 80.

[0060] 3. Details of the charge / discharge control device

[0061] The charge / discharge control device 10 is a backup device capable of outputting power based on the energy storage unit 12. The charge / discharge control device 10 includes a first conductive path 41, a second conductive path 42, a third conductive path 43, a first switch 51, a second switch 52, a voltage conversion unit 30, an auxiliary charging unit 60, a voltage detection unit 14, a control unit 16, and the energy storage unit 12.

[0062] The first conductive path 41 is the path for transmitting power based on the power supply unit 91. A voltage identical or approximately identical to the output voltage of the power supply unit 91 is applied to the first conductive path 41. One end of the first conductive path 41 is electrically connected to the first power circuit 81. The potential of the first conductive path 41 is, for example, set to be the same as a portion or all of the potential of the first power circuit 81. The other end of the first conductive path 41 is electrically connected to one end of the first switch 51.

[0063] The second conductive path 42 is a conductive circuit sandwiched between the second power path 82 and the first conductive path 41, and also between the first conductive path 41 and the voltage conversion unit 30. When the first switch 51 (described later) is in the ON state, the first conductive path 41 and the second conductive path 42 are short-circuited via the first switch 51. When the second switch 52 (described later) is in the ON state, the second conductive path 42 and the second power path 82 are short-circuited via the second switch 52.

[0064] The third conductive path 43 is a conductive circuit electrically connected to the energy storage unit 12, and also electrically connected to one end of the voltage conversion unit 30. When the voltage conversion unit 30 stops, the output voltage of the energy storage unit 12 is applied to the third conductive path 43.

[0065] The first switch 51 is a switch disposed between the first conductive path 41 and the second conductive path 42. The first switch 51 switches between an on state, allowing current to flow from the first conductive path 41 to the second conductive path 42, and an off state, cutting off current flow. For example, when the first switch 51 is on, bidirectional energization is allowed between the first conductive path 41 and the second conductive path 42. When the first switch 51 is off, bidirectional energization is cut off between the first conductive path 41 and the second conductive path 42.

[0066] The second switch 52 is a switch disposed between the second conductive path 42 and the second electrical path 82. The second switch 52 switches between an on state, allowing current to flow from the second conductive path 42 to the second electrical path 82, and an off state, cutting off current flow. For example, when the second switch 52 is on, bidirectional energization is allowed between the second conductive path 42 and the second electrical path 82. When the second switch 52 is off, bidirectional energization is cut off between the second conductive path 42 and the second electrical path 82.

[0067] The voltage conversion unit 30 is a device that performs voltage conversion between the second conductive path 42 and the third conductive path 43. The voltage conversion unit 30 is configured, for example, by a voltage conversion circuit known such as a DC-DC converter. The voltage conversion unit 30 is capable of performing a first conversion operation that steps down or boosts the DC voltage applied to the second conductive path 42 and applies the output voltage to the third conductive path 43. For example, when the first switch 51 is in the ON state, the voltage conversion unit 30 performs the first conversion operation, thereby supplying the energy storage unit 12 with a charging current based on the power from the power supply unit 91. The voltage conversion unit 30 is also capable of performing a second conversion operation that steps down or boosts the DC voltage applied to the third conductive path 43 and applies the output voltage to the second conductive path 42. For example, when the first switch 51 is in the OFF state and the second switch 52 is in the ON state, the voltage conversion unit 30 performs the second conversion operation, thereby applying the DC voltage based on the power from the energy storage unit 12 to the second conductive path 42 and the second power supply path 82. The operation of the voltage conversion unit 30 is controlled by the control unit 16.

[0068] The auxiliary charging unit 60 is a device that charges the energy storage unit 12 via a path different from that via the voltage conversion unit 30. The auxiliary charging unit 60 includes a third switch 64 and an auxiliary charging circuit 62. The auxiliary charging unit 60 switches between a supply state, in which it supplies power to the energy storage unit 12 via a path different from that via the voltage conversion unit 30 based on power supplied via the first conductive path 41, and a stop state, in which it stops the power supply via the path. The path different from that via the voltage conversion unit 30 is the path via the third switch 64 and the auxiliary charging circuit 62, and is a path that does not pass through the first switch 51 and the voltage conversion unit 30.

[0069] The third switch 64 switches the first conductive path 41 and the auxiliary charging circuit 62 between an on and off state. When the third switch 64 is on, power is supplied from the power supply unit 91 to the auxiliary charging circuit 62 via the first conductive path 41 and the third switch 64. When the third switch 64 is off, the power supply via the third switch 64 is cut off in both directions, and current does not flow from the first conductive path 41 to the auxiliary charging circuit 62.

[0070] The auxiliary charging circuit 62 supplies charging current to the energy storage unit 12 when the third switch 64 is in the ON state. The auxiliary charging circuit 62 can be a low-dropout regulator (LDO), a DC-DC converter, or other charging circuits. When using other charging circuits, various methods can be employed, such as constant voltage charging, constant current charging, or constant voltage / constant current charging.

[0071] The control unit 16 is an information processing device with information processing, calculation, and control functions. The control unit 16 is capable of controlling the voltage conversion unit 30 to perform the first conversion operation and the second conversion operation. The control unit 16 controls the on / off states of the first switch 51, the second switch 52, and the third switch 64. The control unit 16 performs the first, second, and third controls described later.

[0072] The voltage detection unit 14 is a circuit that outputs an analog voltage value, which is a value that can determine the voltage applied to the first conductive circuit 41. The voltage detection unit 14 can be a circuit that inputs a voltage value that is the same as the voltage applied to the first conductive circuit 41 to the control unit 16, or it can be a circuit that inputs a value proportional to the voltage applied to the first conductive circuit 41 to the control unit 16. Figure 1 In one example, the voltage detection unit 14 is configured as a voltage divider circuit, and the value obtained by dividing the voltage applied to the first conductive path 41 by the voltage divider circuit is input as a detection value to the control unit 16. The control unit 16 determines the value of the voltage applied to the first conductive path 41 based on the detection value (analog voltage value) input from the voltage detection unit 14.

[0073] exist Figure 1 In the charging and discharging control device 10, the first switch 51, the second switch 52, and the third switch 64 can each be a semiconductor switch such as a FET, or a mechanical relay.

[0074] 4. Operation of the charge / discharge control device

[0075] (First Control)

[0076] Figure 2 This diagram illustrates the first control. The control unit 16 initiates the first control when a predetermined first condition is met. This "first condition" can be, for example, a condition such as "the vehicle is in a running state," or other conditions. For instance, if the vehicle equipped with the vehicle system 2 is in a running state (when the ignition switch or other starter switch is turned on), the control unit 16 determines that the first condition is met and initiates the first control.

[0077] The first control is the control of charging the battery storage unit 12 using a first charging method. Specifically, the first control is the control of turning on the first switch 51 and causing the voltage conversion unit 30 to reduce the voltage applied to the second conductive circuit 42 and apply it to the third conductive circuit 43. Figure 2In this example, the control unit 16 performs the first control by turning off not only the second switch 52 but also the third switch 64. For example, the control unit 16 performs the first control by setting the charging voltage of the battery storage unit 12 when it is fully charged as a first target value and setting the output voltage applied by the voltage conversion unit 30 to the third conductive circuit 43 as the aforementioned first target value. The control unit 16 executes the first control until the termination condition of the first control is met. The termination condition of the first control may be that the charging voltage of the battery storage unit 12 reaches a predetermined value (e.g., the second threshold described later), or that a certain period of time has elapsed since the start of the first control, or the fulfillment of other conditions.

[0078] When the control unit 16 is performing the first control, such as Figure 2 As shown, by keeping the first switch 51 in the ON state and keeping the second switch 52 and the third switch 64 in the OFF state, the voltage conversion unit 30 performs the aforementioned first conversion operation. Through this operation, as... Figure 2 As shown by the thick arrow, a charging current based on the power from the power supply unit 91 is supplied to the energy storage unit 12. Additionally, the second switch 52 can be turned on when the control unit 16 is performing the first control.

[0079] (Secondary Control)

[0080] Figure 3 This diagram illustrates the second control. The control unit 16 initiates the second control when a predetermined second condition is met. This "second condition" could be, for example, a condition like "the first control ends," a condition like "the third control ends," or other conditions. The second control stops the charging of the energy storage unit 12 and discharges it. Specifically, the second control involves setting the first switch 51 to the open state, setting the second switch 52 to the open state, stopping the auxiliary charging unit 60, and causing the voltage conversion unit 30 to boost the voltage applied to the third conductive circuit 43 and apply it to the second conductive circuit 42. Figure 3 In this example, the control unit 16 performs the second control by making not only the first switch 51 but also the third switch 64 open. The control unit 16 performs the second control by setting a second target value that is greater than the charging voltage of the energy storage unit 12 when fully charged and slightly smaller than the charging voltage of the power supply unit 91 when fully charged, and sets the output voltage applied to the second conductive circuit 42 by the voltage conversion unit 30 to the aforementioned second target value.

[0081] When the control unit 16 is performing the second control, such as Figure 3 As shown, the second switch 52 is kept in the ON state, while the first switch 51 and the third switch 64 are kept in the OFF state, and the voltage conversion unit 30 performs the aforementioned second conversion operation. Through this operation, as... Figure 3 As shown by the thick arrow, the voltage based on the power from the energy storage unit 12 is applied to the second power circuit 82. Furthermore, the above example is merely one illustration; for instance, while the control unit 16 is performing second control, the second switch 52 may be kept in the off state, and if the monitoring unit (e.g., the voltage detection unit 14 and the control unit 16) detects that the output voltage of the power supply unit 91 has dropped below a predetermined value, the control unit 16 immediately switches the second switch 52 to the on state.

[0082] Corresponding to the second control, the voltage applied to the second conductive path 42 by the voltage conversion unit 30 is slightly lower than the voltage applied to the first power path 81 by the power supply unit 91 when fully charged. Therefore, if the power supply unit 91 is fully charged and in a normal state (not a failed state, but a state in which power based on the power supply unit 91 can be appropriately supplied to the load 101), then as Figure 3 As shown, current is allowed to flow from the first power circuit 81 to the common power circuit 80, but current is not allowed to flow from the second power circuit 82 to the common power circuit 80. Specifically, if the voltage applied to the end of the first power circuit 81 (the anode of diode 71) is greater than the voltage applied to the end of the second power circuit 82 (the anode of diode 72), then as follows... Figure 3 As shown, only the current in the first power path 81 of the first power path 81 and the second power path 82 flows to the common power path 80.

[0083] However, if, during the second control operation, the voltage applied to the first power circuit 81 is lower than the voltage applied to the second power circuit 82 for some reason, such as... Figure 4 As shown, current immediately flows from the second power circuit 82 to the common power circuit 80. Specifically, if the voltage applied to the end of the first power circuit 81 (the anode of diode 71) is less than the voltage applied to the end of the second power circuit 82 (the anode of diode 72), then as... Figure 4 As shown, only the current in the second power path 82 of the first power path 81 and the second power path 82 flows to the common power path 80.

[0084] (Third Control)

[0085] Figure 5This diagram illustrates the third control. Control unit 16 initiates the third control when a predetermined third condition is met. This "third condition" could be, for example, "during the execution of the second control, the output voltage applied by the battery storage unit 12 to the third conductive circuit 43 reaches below a threshold value," or other conditions. In the representative example described below, the third condition is "during the execution of the second control, the output voltage applied by the battery storage unit 12 to the third conductive circuit 43 reaches below a threshold value (first threshold)." Furthermore, this threshold value (first threshold) is a value greater than 0 and less than the output voltage of the battery storage unit 12 when fully charged. This threshold value (first threshold) can be a predetermined fixed value or a value that can be updated or changed.

[0086] The third control involves setting the first switch 51 to the off state, setting the second switch 52 to the on state, setting the auxiliary charging unit 60 to the supply state (supplying charging current to the energy storage unit 12), and controlling the voltage conversion unit 30 to perform a switching operation that boosts (or reduces) the voltage applied to the third conductive circuit 43 and applies it to the second conductive circuit 42. Figure 3 In the example, the control unit 16 performs third control by turning on the third switch 64 and causing the auxiliary charging circuit 62 to supply charging current to the energy storage unit 12 based on the power from the power supply unit 91 (power supplied via the first conductive path 41). If the third control is performed in this way, then as Figure 5 As shown by the thick arrow, current based on power from the power supply unit 91 is supplied to the battery storage unit 12 via the auxiliary charging unit 60 without passing through the first switch 51, and voltage based on power from the battery storage unit 12 is applied to the second power circuit 82. Furthermore, during the execution of the third control, the control unit 16 terminates the third control if a predetermined termination condition is met. The predetermined termination condition may be that the start switch of the vehicle equipped in the vehicle system 2 is turned off, or that the charging voltage of the battery storage unit 12 reaches a second threshold. In this case, the second threshold is a value greater than the aforementioned threshold (first threshold). The second threshold may, for example, be the charging voltage of the battery storage unit 12 when it is fully charged. During the execution of the third control, if the third control terminates due to the charging voltage of the battery storage unit 12 reaching the second threshold, the control unit 16 switches from the third control to the second control.

[0087] In the third control, the voltage applied to the second conductive path 42 by the voltage conversion unit 30, corresponding to the third control, is also slightly lower than the voltage applied to the first power path 81 by the power supply unit 91 when it is fully charged. Therefore, if the power supply unit 91 is fully charged and in a normal state (not a failed state, but a state in which power based on the power supply unit 91 can be appropriately supplied to the load 101), then as Figure 5As shown, current is allowed to flow from the first power circuit 81 to the common power circuit 80, but current is not allowed to flow from the second power circuit 82 to the common power circuit 80. In this example, if the voltage applied to the end of the first power circuit 81 (the anode of diode 71) is greater than the voltage applied to the end of the second power circuit 82 (the anode of diode 72), then... Figure 5 As shown, only the current in the first power path 81 of the first power path 81 and the second power path 82 flows to the common power path 80.

[0088] However, if, during the third control operation, the voltage applied to the first power circuit 81 is lower than the voltage applied to the second power circuit 82 for some reason, such as... Figure 6 As shown, current immediately flows from the second power circuit 82 to the common power circuit 80. Specifically, if the voltage applied to the end of the first power circuit 81 (the anode of diode 71) is less than the voltage applied to the end of the second power circuit 82 (the anode of diode 72), then as... Figure 6 As shown, only the current in the second power path 82 of the first power path 81 and the second power path 82 flows to the common power path 80.

[0089] 5. Examples of effects

[0090] The charge / discharge control device 10 prepares for backup operation (standby mode with voltage applied to the second power circuit 82) by turning the first switch 51 to the open state and the second switch 52 to the on state, and the voltage conversion unit 30 performs voltage conversion to apply the output voltage to the second conductive circuit 42. If the charge / discharge control device 10 prepares for backup operation before a power failure (specifically, a power failure such as the interruption of power supply from the power supply unit 91 via the first power circuit 81), then the power supply to the load 101 can be resumed immediately after the power failure occurs. Moreover, the charge / discharge control device 10 can continue to prepare for backup operation through the voltage conversion unit 30 and charge the energy storage unit 12 through the auxiliary charging unit 60. In other words, the charge / discharge control device 10 can charge the energy storage unit 12 without interrupting the preparation for backup operation (standby mode with voltage applied), thus easily preventing situations where "the backup operation is slowed down due to a power failure when the preparation for backup operation is interrupted". Thus, the charge / discharge control device 10 has an extremely advantageous structure in that it "suppresses the period during which no power is supplied to the load 101 in the event of a power failure related to the power supply unit 91".

[0091] The charge / discharge control device 10 performs first control via the control unit 16, enabling it to charge the energy storage unit 12 using the voltage conversion unit 30. It also performs second control via the control unit 16, enabling it to discharge the energy storage unit 12 using the voltage conversion unit 30. In other words, the charge / discharge control device 10 can switch between first and second control to charge / discharge the energy storage unit 12 using the voltage conversion unit 30. Furthermore, if the charge / discharge control device 10 determines that charging of the energy storage unit 12 should occur during second control (i.e., while the voltage conversion unit 30 is applying voltage to the second power circuit 82), it can switch from second control to third control. In this case, while the charge / discharge control device 10 continues to perform the "applying voltage to the second power circuit 82 operation (backup preparation operation)," it can increase the charging voltage of the energy storage unit 12, thus preventing the preparation operation from being interrupted while the energy storage unit 12 is charging.

[0092] In the power supply system 3, when a "predetermined voltage drop state" is reached, power is immediately supplied to the load 101 via the second power circuit 82. Therefore, if the charge / discharge control device 10 performs second control by applying an appropriate voltage to the second power circuit 82, power can be immediately supplied to the load 101 via the second power circuit 82 even when the voltage of the first power circuit 81 drops significantly during the second control. Furthermore, when a predetermined condition is met in the second control state, the charge / discharge control device 10 can switch from the second control to the third control, thereby continuing to charge the battery storage unit 12 without significantly interrupting the preparation operation. In the third control, if the third control is performed by applying an appropriate voltage to the second power circuit 82, power can also be immediately supplied to the load 101 via the second power circuit 82 even when the voltage of the first power circuit 81 drops significantly during the second control.

[0093] When the output voltage applied to the third conductive circuit 43 by the energy storage unit 12 drops below a threshold, the charge / discharge control device 10 can continuously charge the energy storage unit 12 without significantly interrupting the preparation operation. Therefore, the charge / discharge control device 10 can prevent the preparation operation from continuing even when the output voltage of the energy storage unit 12 drops below the threshold, thus reducing the likelihood of an excessively low output voltage in the energy storage unit 12 during backup operations corresponding to power failure. Furthermore, the charge / discharge control device 10 prevents significant interruption of the preparation operation as a countermeasure.

[0094] <Other Implementation Methods>

[0095] This disclosure is not limited to the embodiments described above and the accompanying drawings. For example, all combinations of the features of the embodiments described above or later can be made without contradiction. Furthermore, any feature of the embodiments described above or later can be omitted unless explicitly stated as essential. In addition, the above embodiments can also be modified as follows.

[0096] In the first embodiment, the charge / discharge control device 10 is configured to include an energy storage unit 12, but it may also have a structure in which the energy storage unit 12 is disposed outside the charge / discharge control device 10. That is, the energy storage unit 12 may not be included in the charge / discharge control device 10.

[0097] In the first embodiment, the output voltage of the fully charged battery storage unit 12 is less than the output voltage of the fully charged power supply unit 91, but the output voltage of the fully charged battery storage unit 12 can also be greater than the output voltage of the fully charged power supply unit 91. In this case, the first control simply involves turning the first switch 51 on and causing the voltage conversion unit 30 to boost the voltage applied to the second conductive circuit 42 and apply it to the third conductive circuit 43. Furthermore, the second control simply involves turning the first switch 51 off, turning the second switch 52 on, stopping the auxiliary charging unit 60 (not supplying current to the battery storage unit 12), and causing the voltage conversion unit 30 to reduce the voltage applied to the third conductive circuit 43 and apply it to the second conductive circuit 42. Furthermore, the third control only needs to make the first switch 51 open, the second switch 52 open, the auxiliary charging unit 60 supply (supplying current to the energy storage unit 12), and the voltage conversion unit 30 perform the switching operation of reducing the voltage applied to the third conductive circuit 43 and applying it to the second conductive circuit 42.

[0098] In the power supply system 3, when the second or third control is in progress and a predetermined voltage drop state occurs where the voltage of the first power circuit 81 is lower than the voltage of the second power circuit 82, power is supplied to the load 101 via the second power circuit 82. Regarding this, in the first embodiment, the "predetermined voltage drop state" is the state where the voltage of the first power circuit 81 is lower than the voltage of the second power circuit 82, but this is not limited to this example. The "predetermined voltage drop state" could also be the state where the voltage of the first power circuit 81 is lower than the voltage of the second power circuit 82 by a certain value or more. In either case, if the "normal state is not the predetermined voltage drop state," the power supply to the load 101 via the second power circuit 82 is cut off. Furthermore, in either case, when the control unit 16 is performing the second control, the voltage conversion unit 30 performs a conversion operation by applying the output voltage that has become the above-mentioned normal state (specifically, an output voltage where the voltage applied to the second power circuit 82 is slightly lower than the voltage applied to the first power circuit 81) to the second conductive circuit 42.

[0099] In the first embodiment, the control unit 16 can perform first control until the end condition of the first control is met when the first control is performed in accordance with the first condition, and switch from first control to second control in accordance with the end condition of the first control being met, but this is not limited to this example. For example, it may perform first control until the end condition of the first control is met, and then switch from first control to third control. For example, it may switch from first control to third control before the charging voltage of the battery storage unit 12 reaches the second threshold (e.g., the threshold representing a full charge), and switch from third control to second control after the charging voltage of the battery storage unit 12 reaches the second threshold through the third control.

[0100] In the first embodiment, an example of a selection unit is given, but the selection unit 70 is not limited to... Figure 1 The structure shown (based on diodes 71 and 72) can also be used to perform [interactions]. Figure 1The selection section 70 has the same anti-reverse current control structure. For example, a first relay composed of a mechanical relay or a semiconductor relay may be provided instead of diode 71, and a second relay composed of a mechanical relay or a semiconductor relay may be provided instead of diode 72. These first and second relays are preferably designed to allow bidirectional energization when in the ON state and to cut off bidirectional energization when in the OFF state. With such a structure, the voltage of the power supply section 91 (e.g., the voltage of the first power circuit 81) may be monitored by the charge / discharge control device 10, the load 101, or other electronic control device. If the voltage of the power supply section 91 is above a predetermined threshold, the first relay is turned on and the second relay is turned off; if the voltage of the power supply section 91 is below the predetermined threshold, the first relay is turned off and the second relay is turned on. Alternatively, a switching device (not shown) can be used to turn on the first relay and turn off the second relay when the voltage of the first power circuit 81 is greater than the voltage of the second power circuit 82, and to turn off the first relay and turn on the second relay when the voltage of the first power circuit 81 is less than the voltage of the second power circuit 82.

[0101] In the first embodiment, the selection unit 70 is configured as a different element from the charge / discharge control device 10, but the selection unit 70 may also be incorporated as part of the charge / discharge control device 10. Alternatively, the selection unit 70 may also be incorporated as part of the load 101.

[0102] The embodiments disclosed herein should be considered exemplary in all respects and not restrictive. The scope of the invention is not limited to the embodiments disclosed herein, but is indicated by the claims and is intended to include all modifications of the same meaning and scope as those claims.

[0103] Explanation of reference numerals in the attached figures

[0104] 2: Vehicle system

[0105] 3: Vehicle power supply system

[0106] 10: Charge and discharge control device

[0107] 12: Battery Storage Unit

[0108] 14: Voltage Detection Section

[0109] 16: Control Department

[0110] 30: Voltage conversion section

[0111] 41: First conductive path

[0112] 42: Second conductive path

[0113] 43: Third conductive path

[0114] 51: First Switch

[0115] 52: Second switch

[0116] 60: Auxiliary charging unit

[0117] 62: Auxiliary charging circuit

[0118] 64: Third Switch

[0119] 70: Selection Department

[0120] 71: Diode

[0121] 72: Diode

[0122] 80: Shared power line

[0123] 81: First Electric Power Road

[0124] 82: Second Electric Power Line

[0125] 91: Power Supply Section

[0126] 101: Load.

Claims

1. A charging and discharging control device for controlling charging and discharging in a power supply system comprising a power supply unit, a storage unit, a first power path, and a second power path, wherein the first power path is a path for supplying power from the power supply unit to a load, and the second power path is a path for supplying power from the storage unit to the load. The charge / discharge control device has: The first conductive path is the path for transmitting power based on the power source; The second conductive path is sandwiched between the second electrical path and the first conductive path; The third conductive path is electrically connected to the energy storage unit; The voltage conversion unit performs voltage conversion between the second conductive path and the third conductive path; A first switch is disposed between the first conductive path and the second conductive path, and switches between an on state that allows current to flow from the first conductive path to the second conductive path and an off state that cuts off the current. The second switch is located between the second conductive path and the second power path, and switches between an on state that allows current to flow from the second conductive path to the second power path and an off state that cuts off the current. and The auxiliary charging unit switches between a supply state, which supplies power to the energy storage unit via a different path than the voltage conversion unit based on the power supplied through the first conductive path, and a stop state, which stops supplying power to the energy storage unit. The charge / discharge control device has a control unit. The control unit performs first control, second control, and third control. The first control involves turning the first switch on and causing the voltage conversion unit to either boost or deboost the voltage applied to the second conductive circuit and apply it to the third conductive circuit. The second control involves setting the first switch to the off state, setting the second switch to the on state, setting the auxiliary charging unit to the off state, and controlling the voltage conversion unit to boost or deboost the voltage applied to the third conductive circuit and apply it to the second conductive circuit. The third control is to make the first switch open, make the second switch closed, make the auxiliary charging unit supply, and make the voltage conversion unit perform a switching action to increase or decrease the voltage applied to the third conductive circuit and apply it to the second conductive circuit.

2. The charge / discharge control device according to claim 1, wherein, When the power system enters a predetermined voltage drop state where the voltage of the first power circuit is lower than that of the second power circuit, it supplies power to the load via the second power circuit. When it is in a normal state, which is not the predetermined voltage drop state, it cuts off the power supply to the load via the second power circuit. When the control unit performs the second control, it causes the voltage conversion unit to perform the conversion operation to apply the output voltage that has become the normal state to the second conductive circuit. When a predetermined condition is met while the second control is in effect, it switches to the third control.

3. The charge / discharge control device according to claim 2, wherein, The predetermined condition is that the output voltage applied by the energy storage unit to the third conductive circuit reaches below a threshold.

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