Power supply system and control method thereof

Abstract

To provide a power source system in which an electric circuit or a voltage converter that is in an abnormal state is disconnected from another voltage converter that operates normally so that the other voltage converter can be properly protected, and a control method for the power source system.SOLUTION: In a power source system 10, a plurality of batteries 12a to 12d are connected to input sides 34 of a plurality of voltage converters 24a to 24d. Output sides 36 of the plurality of voltage converters 24a to 24d are connected in parallel with each other. In the power source system 10 and a control method therefor, at a point closer to the voltage converters 24a to 24d side than a parallel connection position 39 of the output sides 36 of the plurality of voltage converters 24a to 24d, an abnormality in an electric circuit 51 or an abnormality in the voltage converters 24a to 24d is obtained.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply system in which a plurality of voltage converters are connected in parallel, and a method for controlling the power supply system. [Background technology]

[0002] Patent Document 1 discloses a power supply system including a plurality of voltage conversion units. A power storage unit is connected to the input side of each of the plurality of voltage converters. The output sides of the plurality of voltage converters are connected in parallel with each other. Each of the plurality of voltage converters has a switching element. The switching element is turned on or off by a pulse signal supplied from the outside. In this case, the transformation ratio of the voltage converter changes as the duty of the pulse signal changes. As a result, each of the plurality of voltage converters can convert the voltage of the power storage unit into a desired voltage according to the transformation ratio. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 054828 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if there is an abnormality in the electric circuit on the voltage converter side or in the voltage converter itself, the voltage converter may not be able to convert the voltage of the power storage unit. Specifically, if the supply of a pulse signal to the switching element is interrupted due to a wire break or the like, the switching element cannot be turned on or off. Even if there is an abnormality in the switching element, the switching element cannot be turned on or off. Furthermore, if there is an abnormality in the electric circuit on the input side or output side of the voltage converter, the voltage of the power storage unit cannot be converted or the converted voltage cannot be output. Such an abnormal electric circuit or voltage converter needs to be electrically separated from other voltage converters that are operating normally.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] A first aspect of the present invention relates to a power supply system including a plurality of dischargeable power storage units, and a plurality of voltage converters each having an input side connected to the plurality of power storage units and an output side connected in parallel to each other, converting a voltage of the plurality of power storage units connected to the input side and outputting the converted voltage to the output side. The power supply system includes an acquisition unit that acquires an abnormality in an electric circuit on the voltage converter side relative to a position where the output sides of the plurality of voltage converters are connected in parallel, or an abnormality in the voltage converter.

[0007] A second aspect of the present invention relates to a control method for a power supply system in which a plurality of dischargeable power storage units are connected to input sides of a plurality of voltage converters and the output sides of the plurality of voltage converters are connected in parallel with each other. In the control method, first, an abnormality in an electric circuit on the voltage converter side of a position where the output sides of the plurality of voltage converters are connected in parallel or an abnormality in the voltage converter is obtained. Next, an interrupter arranged in the electric circuit or arranged in the voltage converter is switched to an interrupted state. Effect of the Invention

[0008] According to the present invention, an electric circuit or a voltage converter in an abnormal state can be separated from other voltage converters that are operating normally, thereby making it possible to appropriately protect the other voltage converters. [Brief description of the drawings]

[0009] [Figure 1] 1 is a circuit configuration diagram of a power supply system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram of the voltage converter of FIG. 1. [Diagram 3] FIG. 3 is a circuit diagram of the interrupted portion of FIG. 2. [Figure 4] 4 is a timing chart of a gate signal. [Diagram 5] FIG. 11 is a circuit configuration diagram of a first modified example. [Figure 6] FIG. 13 is a circuit configuration diagram of a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] As shown in Fig. 1, a power supply system 10 according to this embodiment includes a plurality of batteries 12a-12d (power storage units), an equalization unit 14, a control device 16, a motor generator ECU (MG-ECU) 18, and a power drive unit (PDU) 20. Fig. 1 illustrates a case in which four batteries 12a-12d are arranged. Hereinafter, the four batteries 12a-12d are also referred to as first to fourth batteries 12a-12d. It is sufficient that at least two batteries are arranged in the power supply system 10. The power supply system 10 is applied to a power supply system for an electric vehicle 22, such as a two-wheeled vehicle or a four-wheeled vehicle, for example.

[0011] The plurality of batteries 12a to 12d are chargeable and dischargeable. The plurality of batteries 12a to 12d are housed in respective battery packs (not shown). The battery packs are detachable from the power supply system 10. The battery packs include a battery management system (BMU) that monitors the batteries 12a to 12d.

[0012] In this embodiment, it is sufficient that at least one battery pack is detachable from the power supply system 10. Each battery pack, the equalization unit 14, the control device 16, the MG-ECU 18, and the PDU 20 can transmit and receive signals or information via communication lines (not shown) that constitute a CAN (Controller Area Network).

[0013] The equalization unit 14 includes a plurality of voltage converters 24a to 24d, a plurality of current meters 26a to 26d, a plurality of input side voltage meters 28a to 28d, an output side voltage meter 30, and a plurality of temperature sensors 32.

[0014] Each of the multiple voltage converters 24a-24d is, for example, a DC / DC converter having an input side 34 as a primary side and an output side 36 as a secondary side. The multiple voltage converters 24a-24d each converts the voltage of the batteries 12a-12d connected to the input side 34 at an arbitrary transformation ratio Tr. The converted voltage is output to the output side 36 as an output voltage V0. Hereinafter, the voltages of the batteries 12a-12d are also referred to as battery voltages V1-V4. The transformation ratio Tr includes a step-up ratio Tru and a step-down ratio Trd.

[0015] Four voltage converters 24a-24d are disposed in the equalization unit 14 corresponding to the first to fourth batteries 12a-12d. Hereinafter, the four voltage converters 24a-24d are also referred to as the first to fourth voltage converters 24a-24d. In the following description, the first to fourth voltage converters 24a-24d step down the battery voltages V1-V4 at arbitrary step-down rates Tr1-Tr4. Therefore, the stepped-down battery voltages V1-V4 are output to the output side 36 as an output voltage V0.

[0016] The input sides 34 of the first to fourth voltage converters 24a to 24d are connected to the batteries 12a to 12d, respectively. That is, the positive terminals of the first to fourth batteries 12a to 12d are connected to the positive terminals 38p of the input sides 34 of the first to fourth voltage converters 24a to 24d. The negative terminals of the first to fourth batteries 12a to 12d are connected to the negative terminals 38m of the input sides 34 of the first to fourth voltage converters 24a to 24d.

[0017] The output sides 36 of the first to fourth voltage converters 24a to 24d are connected in parallel to each other at the parallel connection position 39. As a result, the first to fourth voltage converters 24a to 24d are connected in parallel to the PDU 20. In this case, the positive terminals 40p of the output sides 36 of the first to fourth voltage converters 24a to 24d are connected to the positive terminal of the PDU 20. The negative terminals 40m of the output sides 36 of the first to fourth voltage converters 24a to 24d are connected to the negative terminal of the PDU 20.

[0018] The multiple input side voltmeters 28a-28d are voltage sensors connected to input sides 34 of the first to fourth voltage converters 24a-24d. That is, the positive terminals of the multiple input side voltmeters 28a-28d are connected to positive terminals 38p of input sides 34 of the first to fourth voltage converters 24a-24d. The negative terminals of the multiple input side voltmeters 28a-28d are connected to negative terminals 38m of input sides 34 of the first to fourth voltage converters 24a-24d. In the following description, the four input side voltmeters 28a-28d in equalization unit 14 are also referred to as first to fourth voltmeters 28a-28d.

[0019] The multiple current measuring devices 26a-26d are current sensors connected between the positive terminals of the first to fourth voltage measuring devices 28a-28d and positive terminals 38p of the first to fourth voltage converters 24a-24d on the input sides 34 of the first to fourth voltage converters 24a-24d. In the following description, the four current measuring devices 26a-26d in the equalization unit 14 are also referred to as the first to fourth current measuring devices 26a-26d.

[0020] The output voltage measurement device 30 is a voltage sensor connected between the positive terminal and the negative terminal of the PDU 20 on the output side 36 of the first to fourth voltage converters 24a to 24d.

[0021] The plurality of temperature sensors 32 detect the temperatures of the switching elements 42H, 42L (see FIG. 2) included in the first to fourth voltage converters 24a to 24d, respectively. FIG. 1 illustrates a case where two temperature sensors 32 are provided.

[0022] The PDU 20 has a three-phase bridge type inverter. First to fourth voltage converters 24a to 24d are connected in parallel to the input side of the PDU 20. A three-phase AC motor 44 is electrically connected to the output side of the PDU 20. The motor 44 is a load of the power supply system 10.

[0023] During power running, DC power is supplied to the PDU 20 from the first to fourth batteries 12a to 12d via the first to fourth voltage converters 24a to 24d. The PDU 20 converts the DC power into three-phase AC power and supplies it to the motor 44. As a result, the electric vehicle 22 is driven by the motor 44 to run.

[0024] During regeneration, the PDU 20 converts the AC power generated by the motor 44 into DC power, thereby causing the PDU 20 to charge the first to fourth batteries 12a to 12d via the first to fourth voltage converters 24a to 24d.

[0025] The MG-ECU 18 is an ECU (electronic control unit) for controlling the PDU 20 and the motor 44. The MG-ECU 18 is capable of transmitting and receiving signals or information between the control unit 16 and the PDU 20.

[0026] That is, the MG-ECU 18 supplies a control signal to the PDU 20. The control signal is a signal indicating a command value for the torque of the motor 44. As a result, the switching elements of the inverter of the PDU 20 are operated in response to the supply of the control signal. Meanwhile, the PDU 20 transmits the state of the PDU 20, etc. to the MG-ECU 18. The motor 44 transmits the state of the motor 44, etc. to the MG-ECU 18. The MG-ECU 18 calculates the required output of the motor 44 based on the information transmitted from the PDU 20 and the motor 44, etc. The calculated required output is transmitted to the control device 16.

[0027] The control device 16 is an ECU for controlling the equalization unit 14. The control device 16 includes an abnormality determination section 45 (first detection section), a control section 46, a command section 48, and a table 50.

[0028] The abnormality determination unit 45 acquires a gate signal as a control signal supplied from the control device 16 to the switching elements 42H, 42L from the equalization unit 14. The abnormality determination unit 45 determines the presence or absence of an abnormality related to the voltage converters 24a-24d based on the acquired gate signal. In this case, the abnormality in question includes an abnormality in an electric circuit 51 on the voltage converters 24a-24d side of the parallel connection position 39 in the equalization unit 14, and an abnormality in the voltage converters 24a-24d. A method for determining the presence or absence of an abnormality will be described later.

[0029] The electric circuit 51 refers to the electric components in the equalization unit 14 between the connection points of the equalization unit 14 with the batteries 12a-12d and the parallel connection position 39. Such components include the wiring on the input side 34 and the output side 36 of the voltage converters 24a-24d, and the circuit elements and wiring such as the switching elements 42H, 42L in the voltage converters 24a-24d. An abnormality in the electric circuit 51 refers to a situation in which the electric circuit 51 does not function normally, such as a broken wire in the wiring. An abnormality in the voltage converters 24a-24d refers to a situation in which the voltage converters 24a-24d cannot perform normal voltage conversion operations.

[0030] The first to fourth voltage meters 28a to 28d measure the battery voltages V1 to V4, respectively. The first to fourth current meters 26a to 26d measure the first to fourth currents I1 to I4, respectively. The output side voltage meter 30 measures the output voltage V0. The multiple temperature sensors 32 measure the temperatures of the first to fourth voltage converters 24a to 24d, respectively. The control unit 46 acquires the measurement results of the first to fourth voltage meters 28a to 28d, the first to fourth current meters 26a to 26d, and the first to fourth currents I1 to I4, as well as the determination result of the abnormality determination unit 45.

[0031] Control unit 46 calculates the transformation ratio Tr and the like based on the required output from MG-ECU 18 and the target value of the current flowing through input side 34 stored in table 50. When the determination result of abnormality determination unit 45 indicates an abnormality in electric circuit 51 or voltage converters 24a-24d, control unit 46 decides to stop the operation of voltage converters 24a-24d related to that electric circuit 51 or voltage converters 24a-24d in an abnormal state.

[0032] The command unit 48 outputs a gate signal, which is a control signal based on the transformation ratio Tr calculated by the control unit 46, to the equalization unit 14. The gate signal is a pulse signal having a duty according to the transformation ratio Tr. The transformation ratio Tr changes by changing the duty. When the control unit 46 decides to stop the operation of the voltage converters 24a-24d, the command unit 48 instructs the equalization unit 14 to stop the operation of the voltage converters 24a-24d.

[0033] Next, a configuration example of the first to fourth voltage converters 24a to 24d will be described with reference to Fig. 2. The first to fourth voltage converters 24a to 24d are, for example, step-down or step-up / step-down DC / DC converters. The configuration and operation of DC / DC converters are well known. Here, a brief description will be given of the connection relationships of the components of the first to fourth voltage converters 24a to 24d.

[0034] A capacitor 52 is connected between the positive terminal 38p and the negative terminal 38m of the input side 34. The following two sets of circuits are connected in parallel to the capacitor 52. That is, two switching elements 42H, 42L connected in series are connected in parallel to the capacitor 52. One end of a coil 54 is connected to the midpoint position of the two switching elements 42H, 42L. In this case, the two switching elements 42H, 42L and the coil 54 form one set of circuits. The capacitor 52 has two sets of circuits connected in parallel.

[0035] In each circuit, one switching element 42H is a high-side switching element connected to the positive terminal 38p side of the capacitor 52. The other switching element 42L is a low-side switching element connected to the negative terminal 38m side of the capacitor 52 and the negative terminal 40m of the output side 36. The other end of the coil 54 is connected to the positive terminal 40p of the output side 36. A capacitor 56 is connected between the positive terminal 40p and the negative terminal 40m of the output side 36.

[0036] Each of the switching elements 42H and 42L includes a metal oxide semiconductor field effect transistor (MOSFET) 58 and a Zener diode 60. The MOSFET 58 and the Zener diode 60 are connected in parallel. The Zener diode 60 is a parasitic diode.

[0037] A gate terminal 62 of each of the switching elements 42H, 42L is connected to a gate signal supply line 64 and a monitor line 66. The gate signal supply line 64 supplies a gate signal from the command unit 48 to the gate terminal 62. As described above, each of the switching elements 42H, 42L is a MOSFET. Therefore, the gate signal is a voltage pulse signal having a duty corresponding to the transformation ratio Tr.

[0038] One end of the monitor line 66 is connected to the connection point between the gate signal supply line 64 and the gate terminal 62. The other end of the monitor line 66 is connected to the abnormality judgment unit 45 (see FIG. 1). Thus, the monitor line 66 extends from the gate terminal 62 to the abnormality judgment unit 45. The monitor line 66 outputs the gate signal supplied to the gate terminal 62 to the abnormality judgment unit 45. The monitor line 66 and the abnormality judgment unit 45 constitute an acquisition unit 67, which will be described later. To avoid complexity, the gate signal supply line 64 and the monitor line 66 are omitted from FIG. 1.

[0039] In each of the above circuits, an interrupted portion 68 is disposed at the midpoint between the two switching elements 42H and 42L. Fig. 2 illustrates a case where the interrupted portion 68 is disposed at a position closer to the switching element 42H than the midpoint. Note that the interrupted portion 68 may be disposed at a position closer to the switching element 42L than the midpoint.

[0040] A signal supply line 70 for supplying a control signal from the command unit 48 is connected to the interrupter 68. The interrupter 68 switches between a disconnected state and a connected state based on the supply of the control signal. When the interrupter 68 is in a connected state, the switching element 42H and the switching element 42L are electrically connected. This enables the first to fourth voltage converters 24a to 24d to perform voltage conversion operations. On the other hand, when the interrupter 68 is in a disconnected state, the switching element 42H and the switching element 42L are electrically disconnected. This disables the voltage conversion operations of the first to fourth voltage converters 24a to 24d.

[0041] 3 shows a circuit configuration of the interrupter 68. The interrupter 68 has a switching element 72, two diodes 74, 76, and two capacitors 78, 80. The interrupter 68 further has a signal supply terminal 82, a high potential side terminal 84, and a low potential side terminal 86. The signal supply terminal 82 is connected to the signal supply line 70 (see FIG. 2). The high potential side terminal 84 is connected to the switching element 42H. The low potential side terminal 86 is connected to the switching element 42L.

[0042] The switching element 72 is a MOSFET. In this case, the anode of the diode 76 is connected to a signal supply terminal 82. The cathode of the diode 76 is connected to a gate terminal of the switching element 72 via a capacitor 80. A control signal is supplied to the gate terminal from the signal supply line 70 via the signal supply terminal 82, the diode 76, and the capacitor 80. The control signal is a voltage signal. The switching element 72 is turned on or off by the supply of the voltage signal.

[0043] A capacitor 78 is connected between the gate terminal and the drain terminal of the switching element 72. A diode 74 is connected between the gate terminal and the source terminal of the switching element 72. The anode of the diode 74 is connected to the source terminal of the switching element 72. The cathode of the diode 74 is connected to the gate terminal of the switching element 72.

[0044] The diodes 74 and 76 are reverse current prevention diodes. The switching speed of the switching element 24 can be adjusted by changing the capacitance of the capacitor 78. The capacitor 80 is a coupling capacitor.

[0045] Here, the command unit 48 (see FIG. 1) supplies a high-level voltage signal to the gate terminal of the switching element 72 via the signal supply line 70, the signal supply terminal 82, the diode 76, and the capacitor 80. This turns on the switching element 72. As a result, the two switching elements 42H, 42L are electrically connected. That is, the interrupter 68 switches to a connected state in which the two switching elements 42H, 42L are electrically connected.

[0046] The command unit 48 supplies a low-level voltage signal to the gate terminal of the switching element 72 via the signal supply line 70, the signal supply terminal 82, the diode 76, and the capacitor 80. This turns the switching element 72 off. As a result, the two switching elements 42H, 42L are electrically cut off. That is, the interrupter 68 switches to a cut-off state in which the two switching elements 42H, 42L are electrically cut off.

[0047] Next, the operation of power supply system 10 according to the present embodiment will be described with reference to Fig. 4. Here, the description will also be made with reference to Figs. 1 to 3. In this description of the operation, a case will be described in which acquisition unit 67 acquires an abnormality in electric circuit 51 or an abnormality in voltage converters 24a to 24d during operation of power supply system 10.

[0048] The command unit 48 supplies a high-level voltage signal to the interrupter unit 68 via the signal supply line 70 under the control of the control unit 46. This turns on the switching element 72 of the interrupter unit 68. As a result, the interrupter unit 68 switches to a connected state. The two switching elements 42H, 42L are electrically connected via the interrupter unit 68.

[0049] Next, the command unit 48 supplies a gate signal to the gate terminals 62 of the switching elements 42H, 42L via the gate signal supply line 64 based on the control by the control unit 46. As a result, the switching elements 42H, 42L are turned on or off according to the duty of the supplied gate signal. As a result, the voltage converters 24a to 24d convert the battery voltages V1 to V4 on the input side 34 at a transformation ratio Tr according to the duty. The converted voltages are output to the output side 36.

[0050] In this case, the monitor line 66 of the acquisition unit 67 outputs the gate signal supplied to the gate terminal 62 to the abnormality determination unit 45. The abnormality determination unit 45 of the acquisition unit 67 acquires the gate signal via the monitor line 66. The abnormality determination unit 45 determines the presence or absence of an abnormality in the electric circuit 51 or the voltage converters 24a to 24d based on the acquired gate signal. The abnormality determination unit 45 outputs the determination result as to the presence or absence of an abnormality to the control unit 46.

[0051] 4 is a timing chart of the gate signal input from the monitoring line 66 (see FIG. 2) to the abnormality determination unit 45 (see FIG. 1). When the input of the gate signal is interrupted at time t1, the abnormality determination unit 45 determines whether the interrupted state continues for a certain period of time T. If the input of the gate signal is subsequently interrupted at time t2, which is the elapse of the certain period of time T from time t1, the abnormality determination unit 45 determines that some abnormality has occurred in the electric circuit 51 or the voltage converters 24a-24d.

[0052] Four voltage converters 24a-24d are disposed in equalization unit 14. Therefore, a monitor line 66 is connected between each of the four voltage converters 24a-24d and abnormality determination unit 45. Therefore, abnormality determination unit 45 determines the presence or absence of an abnormality for each of the four voltage converters 24a-24d and electric circuit 51.

[0053] If the input of the gate signal continues, or if the input of the gate signal is interrupted but resumes before a certain time T has elapsed, the abnormality determination unit 45 determines that the electric circuit 51 or the voltage converters 24a to 24d are normal.

[0054] The abnormality determination unit 45 may compare the gate signal input via the monitoring line 66 with the gate signal transmitted from the command unit 48 to the equalization unit 14. This makes it possible to accurately determine whether or not there is an abnormality in the electric circuit 51 or the voltage converters 24a to 24d.

[0055] Based on the determination result of the abnormality determination unit 45, the control unit 46 determines whether to maintain the connected state of the interrupter 68 or switch it to a cut-off state. The control unit 46 notifies the command unit 48 of the determination result. Here, if the determination result indicates an abnormality in the electric circuit 51 or the voltage converters 24a to 24d, the control unit 46 determines to switch the interrupter 68 to a cut-off state. If the determination result indicates that the electric circuit 51 or the voltage converters 24a to 24d are normal, the control unit 46 determines to maintain the interrupter 68 in a connected state.

[0056] When the decision to switch the interrupter 68 to the cut-off state is notified, the command unit 48 supplies a low-level voltage signal to the interrupter 68 via the signal supply line 70. This turns off the switching element 72. As a result, the interrupter 68 switches to the cut-off state. Therefore, the electrical connection between the two switching elements 42H, 42L is cut off. Therefore, the voltage converters 24a-24d related to the electric circuit 51 determined to be abnormal or the voltage converters 24a-24d determined to be abnormal are unable to perform voltage conversion operations. As a result, the voltage converters 24a-24d are electrically disconnected from the other voltage converters 24a-24d that are operating normally.

[0057] On the other hand, when a decision to maintain the connection state of the interrupter 68 is notified, the command unit 48 continues to supply a high-level voltage signal to the interrupter 68 via the signal supply line 70. This causes the interrupter 68 to maintain the connection state. As a result, the voltage converters 24a to 24d can continue to perform the voltage conversion operation.

[0058] Figure 5 shows a first modified example of power supply system 10 according to the present embodiment. The same components as those in Figures 1 to 3 are given the same reference numerals and detailed description will be omitted. In the first modified example, abnormality determination unit 45 of acquisition unit 67 determines the presence or absence of an abnormality in electric circuit 51 based on the current flowing through output side 36 of voltage converters 24a to 24d.

[0059] In the first modified example, a current meter 90 (second detection unit) is connected in series to each of the two coils 54. Each current meter 90 sequentially detects the current flowing through the coil 54. The detection results of each current meter 90 are sequentially output to the abnormality determination unit 45 via the monitoring line 66. Therefore, in the first modified example, the acquisition unit 67 has each current meter 90, the monitoring line 66, and the abnormality determination unit 45.

[0060] Between the positive electrode terminal 40p of the output side 36 and the connection point of the other ends of the two coils 54, two interrupted portions 68a, 68b are connected in series.

[0061] One of the interrupting portions 68a (first unidirectional interrupting portion) has a MOSFET 92a and a diode 94a. The MOSFET 92a and the diode 94a are connected in parallel.

[0062] The MOSFET 92a is turned on or off by a voltage signal supplied to the gate terminal from the command unit 48 via the signal supply line 70a. In this case, when a high-level voltage signal is supplied to the gate terminal, the MOSFET 92a is turned on. This causes the interruption unit 68a to be in a connected state. As a result, each coil 54 and the other interruption unit 68b are electrically connected. On the other hand, when a low-level voltage signal is supplied to the gate terminal, the MOSFET 92a is turned off. This causes the interruption unit 68a to be in a cut-off state. As a result, each coil 54 and the other interruption unit 68b are electrically cut off.

[0063] The diode 94a allows current to flow from each coil 54 to the positive terminal 40p. The diode 94a blocks current flow from the positive terminal 40p to each coil 54. Therefore, the interrupting portion 68a allows current to flow from the voltage converters 24a-24d to the parallel connection position 39. The interrupting portion 68a blocks current flow from the parallel connection position 39 to the voltage converters 24a-24d.

[0064] The other interruption portion 68b (second unidirectional interruption portion) has a MOSFET 92b and a diode 94b. The MOSFET 92b and the diode 94b are connected in parallel.

[0065] The MOSFET 92b is turned on or off by a voltage signal supplied to the gate terminal from the command unit 48 via the signal supply line 70b. In this case, when a high-level voltage signal is supplied to the gate terminal, the MOSFET 92b is turned on. This causes the interruption unit 68b to be in a connected state. As a result, one interruption unit 68a and the positive terminal 40p are electrically connected. On the other hand, when a low-level voltage signal is supplied to the gate terminal, the MOSFET 92b is turned off. This causes the interruption unit 68b to be in a cut-off state. As a result, one interruption unit 68a and the positive terminal 40p are electrically cut off.

[0066] The diode 94b allows current to flow from the positive terminal 40p to one of the interrupting portions 68a. The diode 94b blocks current flow from one of the interrupting portions 68a to the positive terminal 40p. Therefore, the interrupting portion 68b allows current to flow from the parallel connection position 39 to the voltage converters 24a-24d. The interrupting portion 68b blocks current flow from the voltage converters 24a-24d to the parallel connection position 39.

[0067] In the first modified example, abnormality determination unit 45 determines whether or not the detection results input from two current measuring devices 90 via monitoring line 66, i.e., the current value, is equal to or greater than a predetermined value. When at least one of the detection results from two current measuring devices 90 is equal to or greater than a predetermined value, abnormality determination unit 45 determines that some abnormality has occurred in electric circuit 51. In other words, abnormality determination unit 45 determines that an abnormality has occurred in electric circuit 51 including voltage converters 24a-24d.

[0068] If the determination result indicates an abnormality in the electric circuit 51, the control unit 46 decides to switch the interrupting units 68a, 68b to the cut-off state. In response to the determination of the control unit 46, the command unit 48 supplies a low-level voltage signal to the MOSFETs 92a, 92b via the signal supply lines 70a, 70b. This turns off the MOSFETs 92a, 92b. As a result, the interrupting units 68a, 68b switch from the connected state to the cut-off state. Therefore, the voltage converters 24a-24d related to the electric circuit 51 determined to be abnormal are unable to perform voltage conversion operations. Therefore, the voltage converters 24a-24d are electrically disconnected from the other voltage converters 24a-24d that are operating normally.

[0069] If the determination result indicates that the electric circuit 51 is normal, the control unit 46 determines to maintain the on-state of the on-state of the interrupting units 68a, 68b. In response to the determination of the control unit 46, the command unit 48 maintains the supply of a high-level voltage signal to the MOSFETs 92a, 92b via the signal supply lines 70a, 70b. This causes the MOSFETs 92a, 92b to maintain the on-state. As a result, the on-state of the interrupting units 68a, 68b is maintained. Therefore, the voltage converters 24a-24d can continue to perform the voltage conversion operation.

[0070] In the second modified example of FIG. 6, one current meter 90 is disposed between the connection point of the two coils 54 and one of the intermittent portions 68a. Therefore, the acquisition unit 67 has one current meter 90, a monitoring line 66, and an abnormality determination unit 45 (see FIG. 1). In the second modified example, the current meter 90 sequentially detects the current flowing through the output side 36. The measurement results of the current meter 90 are sequentially output to the abnormality determination unit 45 via the monitoring line 66. As a result, the second modified example also has the same effect as the first modified example (see FIG. 5).

[0071] As described above, this embodiment relates to a power supply system 10 including a plurality of dischargeable batteries 12a-12d (power storage units) and a plurality of voltage converters 24a-24d having input sides 34 connected to the plurality of batteries 12a-12d and output sides 36 connected in parallel to one another, converting voltages (battery voltages V1-V4) of the plurality of batteries 12a-12d connected to the input side 34 and outputting the converted battery voltages V1-V4 to the output side 36. The power supply system 10 includes an acquisition unit 67 that acquires an abnormality in an electric circuit 51 on the voltage converter 24a-24d side relative to a parallel connection position 39 of the output sides 36 of the plurality of voltage converters 24a-24d, or an abnormality in the voltage converters 24a-24d.

[0072] The present embodiment also relates to a control method for a power supply system 10 in which a plurality of dischargeable batteries 12a-12d are connected to input sides 34 of a plurality of voltage converters 24a-24d and output sides 36 of the plurality of voltage converters 24a-24d are connected in parallel to one another. In this control method, first, an abnormality in an electric circuit 51 on the voltage converter 24a-24d side of a parallel connection position 39 of the output sides 36 of the plurality of voltage converters 24a-24d or an abnormality in the voltage converters 24a-24d is obtained. Next, interrupters 68, 68a, 68b arranged in the electric circuit 51 or in the voltage converters 24a-24d are switched to an interrupted state.

[0073] In this way, the electric circuit 51 or the voltage converters 24a to 24d in an abnormal state can be separated from the other voltage converters 24a to 24d that are operating normally, thereby making it possible to appropriately protect the other voltage converters 24a to 24d.

[0074] Here, the power supply system 10 includes interrupters 68, 68a, 68b that are disposed in the electric circuit 51 or in the voltage converters 24a to 24d and switch between a disconnected state and a connected state, and a control unit 46 that controls the interrupters 68, 68a, 68b.

[0075] This makes it possible to easily separate the electric circuit 51 or the voltage converters 24a to 24d in an abnormal state from the other normal voltage converters 24a to 24d.

[0076] In this case, when the acquisition unit 67 acquires an abnormality in the electric circuit 51 or an abnormality in the voltage converters 24a to 24d, the control unit 46 controls the on / off units 68, 68a, 68b to the interrupted state.

[0077] This allows the interrupting portions 68, 68a, 68b to be switched to the interrupted state accurately and reliably.

[0078] Each of the voltage converters 24a to 24d is configured by connecting two sets of circuits, each set consisting of two switching elements 42H, 42L connected in series, in parallel between the input side 34 and the output side 36. In this case, the interrupter 68 is disposed at the midpoint of the two switching elements 42H, 42L connected in series.

[0079] As a result, when the interrupter 68 is switched to the interrupted state, the voltage converters 24a-24d are unable to perform voltage conversion operations. As a result, the abnormal voltage converters 24a-24d can be easily and reliably separated from the other normal voltage converters 24a-24d.

[0080] Acquiring unit 67 has an abnormality determining unit 45 (first detecting unit) that acquires (detects) a gate signal (control signal) for controlling voltage converters 24a to 24d. When the abnormality determining unit 45 cannot detect a gate signal for a certain time T (predetermined time) or longer, it determines that an abnormality has occurred in voltage converters 24a to 24d.

[0081] If the gate signal cannot be detected, there is a possibility that the voltage conversion operation of the voltage converters 24a-24d is not being performed properly. Therefore, if the gate signal cannot be detected for a certain period of time T or longer, the voltage converter 24a-24d is determined to be abnormal. This makes it possible to reliably separate the voltage converter 24a-24d determined to be abnormal from the other normal voltage converters 24a-24d.

[0082] The multiple interrupting parts 68a, 68b are arranged in series with each other in the electric circuit 51. In this case, one interrupting part 68a functions as a first unidirectional interrupting part that allows current to flow from the voltage converters 24a-24d to the parallel connection position 39 and blocks current flow from the parallel connection position 39 to the voltage converters 24a-24d. The other interrupting part 68b functions as a second unidirectional interrupting part that allows current to flow from the parallel connection position 39 to the voltage converters 24a-24d and blocks current flow from the voltage converters 24a-24d to the parallel connection position 39.

[0083] This makes it possible to easily and reliably separate the normally operating voltage converters 24a-24d from the abnormal electric circuit 51. It is possible to cut off overcurrents such as circulating currents flowing from the abnormal electric circuit 51 to the voltage converters 24a-24d.

[0084] The acquiring unit 67 has a current meter 90 (second detecting unit) that detects a current flowing through the electric circuit 51. The acquiring unit 67 determines that an abnormality has occurred in the electric circuit 51 when the current meter 90 detects a current equal to or greater than a predetermined value.

[0085] This makes it possible to easily and reliably separate the normally operating voltage converters 24a-24d from the abnormal electric circuit 51. As a result, overcurrents such as circulating currents flowing from the abnormal electric circuit 51 to the voltage converters 24a-24d can be cut off.

[0086] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0087] 10…Power supply system 12a to 12d: Battery (electric storage unit) 24a to 24d: Voltage converter 34...Input side 36...Output side 39: Parallel connection position 45: Abnormality judgment section 51...electrical circuit 67...acquisition section 68, 68a, 68b...Intermittent section

Claims

1. A plurality of dischargeable power storage units; a plurality of voltage converters each having an input side connected to the plurality of power storage units and an output side connected in parallel to one another, the voltage converters converting voltages of the plurality of power storage units connected to the input side and outputting the converted voltages to the output side; In a power supply system comprising: an acquisition unit that acquires an abnormality in an electric circuit on the voltage converter side relative to a parallel connection position of the output sides of the plurality of voltage converters, or an abnormality in the voltage converter; The acquisition unit has a first detection unit that detects a control signal for controlling the voltage converter, and when the first detection unit cannot detect the control signal for a predetermined period of time or longer, it determines that an abnormality has occurred in the voltage converter.

2. 2. The power supply system according to claim 1, An interrupter arranged in the electric circuit or in the voltage converter, the interrupter being switched between a disconnected state and a connected state; A control unit that controls the interrupter; A power supply system comprising:

3. A plurality of dischargeable power storage units; a plurality of voltage converters each having an input side connected to the plurality of power storage units and an output side connected in parallel to one another, the voltage converters converting voltages of the plurality of power storage units connected to the input side and outputting the converted voltages to the output side; In a power supply system comprising: an acquisition unit that acquires an abnormality in an electric circuit on the voltage converter side relative to a parallel connection position of the output sides of the plurality of voltage converters, or an abnormality in the voltage converter; An interrupter arranged in the electric circuit or in the voltage converter, the interrupter being switched between a disconnected state and a connected state; A control unit that controls the interrupter; Equipped with A plurality of the interrupted portions are arranged in series with each other in the electric circuit, The plurality of interrupted portions include a first unidirectional interrupting portion that allows a current to flow from the voltage converter to the parallel connection position and that blocks a current to flow from the parallel connection position to the voltage converter; a second unidirectional interrupting portion that allows a current to flow from the parallel connection position to the voltage converter and blocks a current to flow from the voltage converter to the parallel connection position; That is, the power supply system.

4. 4. The power supply system according to claim 2, The control unit controls the interrupter to the interrupted state when the acquisition unit acquires the abnormality in the electric circuit or the abnormality in the voltage converter.

5. In the power supply system according to claim 2 or claim 4 depending on claim 2, the voltage converter is configured by connecting two sets of circuits, each set being made up of two switching elements connected in series, in parallel between the input side and the output side; A power supply system, wherein the interrupting portion is disposed at a midpoint position of two of the switching elements connected in series.

6. In the power supply system according to claim 3 or claim 4 depending on claim 3, A power supply system, wherein the acquisition unit has a second detection unit that detects a current flowing through the electrical circuit, and when the second detection unit detects a current equal to or greater than a predetermined value, it determines that an abnormality has occurred in the electrical circuit.

7. A control method for a power supply system in which a plurality of dischargeable power storage units are connected to input sides of a plurality of voltage converters and output sides of the plurality of voltage converters are connected in parallel to each other, comprising: When a control signal for controlling the voltage converter cannot be detected for a predetermined period of time or longer, it is determined that the voltage converter is abnormal; A control method for a power supply system, comprising: switching an interrupter disposed in the voltage converter to an interrupted state.

8. A control method for a power supply system in which a plurality of dischargeable power storage units are connected to input sides of a plurality of voltage converters, and the output sides of the plurality of voltage converters are connected in parallel to each other, comprising: acquiring an abnormality in an electric circuit on the voltage converter side relative to a parallel connection position of the output sides of the plurality of voltage converters, or an abnormality in the voltage converter; Switching an interrupter disposed in the electric circuit or in the voltage converter to an interrupted state; A plurality of the interrupted portions are arranged in series with each other in the electric circuit, The plurality of interrupted portions include a first unidirectional interrupting portion that allows a current to flow from the voltage converter to the parallel connection position and that blocks a current to flow from the parallel connection position to the voltage converter; a second unidirectional interrupting portion that allows a current to flow from the parallel connection position to the voltage converter and blocks a current to flow from the voltage converter to the parallel connection position; A method for controlling a power supply system.

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