Power supply circuit and power supply system

Abstract

The power supply circuit (70) is provided with a power conversion circuit (72). A terminal voltage of a first DC voltage source (60) and a terminal voltage of a second DC voltage source (82) are applied to the power conversion circuit. The power supply circuit includes a bypass path. The bypass path is a path that bypasses the power conversion circuit and connects the first DC voltage source and the electrical load, and is provided with a shutter (76) that opens and closes the path.

Description

Technical Field

[0001] The present disclosure relates to a power supply circuit and a power supply system. Background Art

[0002] For example, Patent Document 1 below describes a power conversion circuit that takes the terminal voltage of a first DC voltage source and the terminal voltage of a second DC voltage source as inputs. In this power conversion circuit, the switching elements for processing to convert the terminal voltage of the first DC voltage source and the switching elements for processing to convert the terminal voltage of the second DC voltage source are shared. According to this power conversion circuit, even when an abnormality occurs in either of the two of the first DC voltage source and the second DC voltage source, it is possible to use the other to supply power to an electrical load.

[0003] Patent Document 1: Japanese Patent No. 5492040 Gazette

[0004] In the case of the above power conversion circuit, if an abnormality occurs in the switching element, power from either the first DC voltage source or the second DC voltage source may not be supplied to the electrical load. Summary of the Invention

[0005] In one aspect of the present disclosure, a power supply circuit is provided. The power supply circuit includes: a power conversion circuit configured to apply an output voltage to an electrical load; and a bypass path. The power conversion circuit is configured to be applied with the terminal voltage of a first DC voltage source and the terminal voltage of a second DC voltage source, and includes a first inductor, a second inductor, and a plurality of switching elements. The plurality of switching elements are configured to open and close a first loop path, a second loop path, a third loop path, and a fourth loop path respectively. The plurality of switching elements that open and close the first loop path and the second loop path and the plurality of switching elements that open and close the third loop path and the fourth loop path are shared elements. The first loop path is a path that includes the first DC voltage source and the first inductor and does not include the output terminal of the power conversion circuit. The second loop path is a path that includes the first DC voltage source, the first inductor, and the output terminal of the power conversion circuit. The third loop path is a path that includes the second DC voltage source and the second inductor and does not include the output terminal of the power conversion circuit. The fourth loop path is a path that includes the second DC voltage source, the second inductor, and the output terminal of the power conversion circuit. The bypass path is a path that bypasses the power conversion circuit and connects the first DC voltage source and the electrical load, and includes a switch for opening and closing this bypass path. Brief Description of the Drawings

[0006] Figure 1 This is a diagram showing the structure of the vehicle-mounted system according to the first embodiment.

[0007] Figure 2 This is showing Figure 1 the circuit diagram of the power supply circuit in the vehicle-mounted system of

[0008] Figure 3A and Figure 3B This is the circuit diagram showing the power conversion process with the power of the battery as the input.

[0009] Figure 4A and Figure 4B This is the circuit diagram showing the power conversion process with the power of the capacitor as the input.

[0010] Figure 5 This is the timing diagram illustrating the operation of the power supply circuit according to the first embodiment.

[0011] Figure 6 This is the timing diagram showing the control example of the output voltage of the second power conversion circuit according to the first embodiment.

[0012] Figure 7 This is a diagram showing the structure of the vehicle-mounted system according to the second embodiment.

[0013] Figure 8 This is showing Figure 7 the circuit diagram of the power supply circuit in the vehicle-mounted system of Detailed implementation mode

[0014] <First embodiment>

[0015] Hereinafter, the first embodiment will be described with reference to the accompanying drawings.

[0016] "Overall structure"

[0017] In Figure 1 the structure of the power supply system according to the present embodiment is shown.

[0018] As Figure 1As shown, the steering control device 10 of the vehicle according to this embodiment includes a steering wheel 12, a steering shaft 14, a reaction force motor 16, a reaction force inverter 18, and a reaction force reduction mechanism 20. The steering shaft 14 is connected to the steering wheel 12. The reaction force motor 16 applies a force that resists steering operation, i.e., a steering operation reaction force, to the steering wheel 12 via the steering shaft 14. The reaction force motor 16 is connected to the steering shaft 14 via the reaction force reduction mechanism 20. As an example, the reaction force motor 16 is a three-phase synchronous motor. The reaction force inverter 18 is a DC-AC conversion circuit that converts the voltage of a DC voltage source into an AC voltage and applies it to the reaction force motor 16. The reaction force reduction mechanism 20 is constituted by, for example, a worm gear.

[0019] The steering control device 10 includes a steering wheel 30, a rack shaft 32, a steering motor 34, and a steering inverter 36. The steering wheel 30 changes the rotation angle of the tire by the axial displacement of the rack shaft 32. The rack shaft 32 axially displaces as the steering motor 34 rotates. As an example, the steering motor 34 is a three-phase synchronous motor. The steering inverter 36 is a DC-AC conversion circuit that converts the voltage of a DC voltage source into an AC voltage and applies it to the steering motor 34.

[0020] The reaction force motor 16 and the reaction force inverter 18 are housed in the housing Hb of the reaction force control unit 40. The reaction force control unit 40 uses the steering wheel 12 as a control object. That is, the reaction force control unit 40 controls the control amount of the steering wheel 12 as the control object, i.e., the steering operation reaction force that resists the driver's steering operation.

[0021] The reaction force control unit 40 includes a reaction force power supply IC 42 and a reaction force microcomputer 44. The reaction force power supply IC 42 is an integrated circuit that supplies power to the reaction force microcomputer 44 when the IG signal becomes an on state. The reaction force microcomputer 44 makes the reaction force power supply relay 46 become an on state when it becomes an on state. That is, the reaction force microcomputer 44 makes the reaction force power supply relay 46 become a closed state when the IG signal becomes an on state.

[0022] The IG signal is a vehicle driving permission signal. The driving permission signal is a signal for switching the vehicle to a state where it can travel. For example, in the case of a vehicle whose thrust generation device is only an internal combustion engine, the driving permission signal is an ignition signal. In addition, in the case of a vehicle whose thrust generation device is a motor, the driving permission signal may also be a signal for switching the relay provided between the motor and the battery to a closed state.

[0023] In addition, as an example, the reaction force power supply relay 46 is a field effect transistor. In particular, in Figure 1An example is shown in which the cathode of the body diode is connected to the reaction force microcomputer 44.

[0024] The reaction force microcomputer 44 is a control circuit that operates the reaction force inverter 18 to control the reaction force torque applied to the steering wheel 12.

[0025] The steering motor 34 and the steering inverter 36 are housed in the housing Hc of the steering control unit 50. The steering control unit 50 sets the steering wheel 30 as the control object. That is, the steering control unit 50 controls the rotation angle of the tire of the steering wheel 30 that is the control object.

[0026] The steering control unit 50 includes a steering power supply IC 52 and a steering microcomputer 54. The steering power supply IC 52 is an integrated circuit that supplies power to the steering microcomputer 54 when the IG signal becomes on. The steering microcomputer 54 makes the steering power supply relay 56 become on when it becomes on.

[0027] In addition, as an example, the steering power supply relay 56 is a field effect transistor. In particular, in Figure 1 an example is shown in which the cathode of the body diode is connected to the steering microcomputer 54.

[0028] The steering microcomputer 54 is a control circuit that operates the steering inverter 36 to control the torque of the steering motor 34.

[0029] Power from the battery 60 is supplied to the reaction force control unit 40 and the steering control unit 50 via the power supply circuit 70. The battery 60 is a secondary battery such as a lead storage battery, a nickel-metal hydride secondary battery, or a lithium-ion secondary battery. The terminal voltage of the battery 60 can be, for example, several volts to several tens of volts. The terminal voltage of the battery 60 can also be more than ten volts.

[0030] The power supply circuit 70 includes a power supply terminal TP and a control terminal TC. The power supply terminal TP is a terminal for supplying power to the actuator system. That is, the power supply terminal TP is a terminal for supplying power to the reaction force inverter 18 and the steering inverter 36. In addition, the control terminal TC is a terminal for supplying power to the control section that operates the actuator system. That is, the control terminal TC is a terminal for supplying power to the reaction force power supply IC 42, the reaction force microcomputer 44, the steering power supply IC 52, and the steering microcomputer 54.

[0031] That is, power from the control terminal TC is supplied to the reaction force power supply IC 42 and the steering power supply IC 52. In addition, power from the power supply terminal TP can be supplied to the reaction force power supply IC 42 via the reaction force power supply relay 46. In addition, power from the power supply terminal TP can be supplied to the steering power supply IC 52 via the steering power supply relay 56.

[0032] In addition, electric power from the power supply terminal TP can be supplied to the reaction force inverter 18 via the reaction force power relay 46 by the reaction force. In addition, electric power from the power supply terminal TP can be supplied to the steering inverter 36 via the steering power relay 56.

[0033] The positive terminal of the battery 60 is connected to the power supply terminal TS of the power supply circuit 70. The negative terminal of the battery 60 is connected to the ground terminal TG of the power supply circuit 70. In addition, the negative terminal of the battery 60 is connected to the reaction force control unit 40 and the steering control unit 50 via a ground wiring LG that bypasses the power supply circuit 70. The ground wiring LG is located outside the housing Ha that houses the power supply circuit 70, the housing Hb that houses the reaction force control unit 40, and the housing Hc that houses the steering control unit 50. The ground wiring LG can be, for example, a cable with an insulating coating.

[0034] "Regarding the power supply circuit"

[0035] In Figure 2 the structure of the power supply circuit 70 is shown.

[0036] The power supply circuit 70 includes a first power conversion circuit 72. The first power conversion circuit 72 includes a series connection of four switching elements SW1 to SW4. The terminal of the two input / output terminals of the switching element SW1 that is not connected to the switching element SW2 is the output terminal of the first power conversion circuit 72. One of the two input / output terminals of the switching element SW4 that is not connected to the switching element SW3 is connected to the ground terminal TG.

[0037] The switching elements SW1 to SW4 are all field effect transistors. Body diodes are formed in the switching elements SW1 to SW4 respectively. The forward direction of these body diodes is the direction from the ground terminal TG side to the output side of the first power conversion circuit 72. The first power conversion circuit 72 includes a first inductor 72a connected to the connection point of the switching element SW2 and the switching element SW3. In addition, the first power conversion circuit 72 includes a second inductor 72b connected to the connection point of the switching element SW1 and the switching element SW2.

[0038] One of the two terminals of the first inductor 72a that is not connected to the connection point of the switching element SW2 and the switching element SW3 is connected to the power relay 74. The power relay 74 opens and closes between the power supply terminal TS and the first power conversion circuit 72. The power relay 74 is a normally open relay. The power relay 74 is composed of a series connection of two switching elements SW5 and SW6. As an example, the switching elements SW5 and SW6 are field effect transistors. In particular, in Figure 2An example is shown in which the anodes of the body diodes of the switching elements SW5 and SW6 are connected to each other.

[0039] If the power relay 74 is in the closed state, the terminal voltage of the battery 60 is applied to the first inductor 72a.

[0040] A smoothing capacitor 73 is connected to the output terminal of the first power conversion circuit 72. Thus, the output voltage of the first power conversion circuit 72 is applied to the smoothing capacitor 73. The terminal of the two terminals of the smoothing capacitor 73 that is not connected to the output terminal is connected to the ground terminal TG.

[0041] The first power conversion circuit 72 is a circuit that converts the terminal voltage of the battery 60 to generate an output voltage. Specifically, the switching elements SW1 to SW4 in the first power conversion circuit 72 and the first inductor 72a constitute a buck-boost chopper circuit that takes the terminal voltage of the battery 60 as the input voltage.

[0042] In Figure 3A and Figure 3B the operation of the first power conversion circuit 72 as a buck-boost chopper circuit taking the terminal voltage of the battery 60 as the input voltage is shown.

[0043] Figure 3A It represents a state in which the switching elements SW1 and SW2 are turned off and the switching elements SW3 and SW4 are turned on. In this case, the first loop path composed of the battery 60, the first inductor 72a, and the switching elements SW3 and SW4 becomes a closed state. Thus, the current flowing from the positive terminal of the battery 60 to the first inductor 72a gradually increases.

[0044] Figure 3B It represents a state in which the switching elements SW1 and SW2 are turned on and the switching elements SW3 and SW4 are turned off. In this case, the second loop path including the battery 60, the first inductor 72a, and the switching elements SW1 and SW2 becomes a closed state. The second loop path includes the output terminal of the first power conversion circuit 72. Therefore, the second loop path is a path including components outside the first power conversion circuit 72. For example, the second loop path includes the smoothing capacitor 73. Thus, the current flows from the positive pole of the battery 60 through the first inductor 72a to the smoothing capacitor 73. At this time, the current flowing in the first inductor 72a gradually decreases.

[0045] Return Figure 2, the first power conversion circuit 72 is a circuit that converts the charging voltage of the capacitor 82 to generate an output voltage. Specifically, the switching elements SW1 to SW4 in the first power conversion circuit 72 and the second inductor 72b constitute a buck-boost chopper circuit that uses the charging voltage of the capacitor 82 as the input voltage. The capacitor 82 is a lithium-ion capacitor. As an example, the upper limit value of the charging voltage of the capacitor 82 is lower than the terminal voltage of the battery 60. Additionally, as an example, the full charge amount of the capacitor 82 is smaller than the full charge amount of the battery 60.

[0046] In Figure 4A and Figure 4B , the operation of the first power conversion circuit 72 as a buck-boost chopper circuit using the charging voltage of the capacitor 82 as the input voltage is shown during its operation.

[0047] Figure 4A represents a state in which the switching elements SW2 and SW3 are turned on and the switching elements SW1 and SW4 are turned off. In this case, the third loop path formed by the capacitor 82, the second inductor 72b, and the switching elements SW2 and SW3 becomes a closed state. As a result, the current flowing from the positive electrode of the capacitor 82 to the second inductor 72b gradually increases.

[0048] Figure 4B represents a state in which the switching elements SW1 and SW4 are turned on and the switching elements SW2 and SW3 are turned off. In this case, the fourth loop path including the capacitor 82, the second inductor 72b, and the switching elements SW1 and SW4 becomes a closed state. The fourth loop path includes the output terminal of the first power conversion circuit 72. Therefore, the fourth loop path becomes a path that includes components outside the first power conversion circuit 72. For example, the fourth loop path includes the smoothing capacitor 73. As a result, the current flows from the positive electrode of the capacitor 82 through the second inductor 72b to the smoothing capacitor 73. At this time, the current flowing through the second inductor 72b gradually decreases.

[0049] Return Figure 2 , the output terminal of the first power conversion circuit 72 is connected to the power supply terminal TP. The above-mentioned smoothing capacitor 73 is connected between the ground terminal TG and the power supply terminal TP. That is, the smoothing capacitor 73 is connected in parallel with the reaction force inverter 18 and the steering inverter 36. Therefore, the second loop circuit and the fourth loop circuit can also be said to be paths that include the reaction force inverter 18 and the steering inverter 36.

[0050] A node N1 between the output terminal of the first power conversion circuit 72 and the power supply terminal TP is connected to the power supply terminal TS via a bypass relay 76 that serves as a switch. The bypass relay 76 is a switch that opens and closes the electrical path between the power supply terminal TS and the node N1. Therefore, when the bypass relay 76 is in the closed state, the terminal voltage of the battery 60 is applied to the node N1. In addition, the electrical path between the power supply terminal TS, the bypass relay 76, and the node N1 constitutes a detour path that bypasses the first power conversion circuit 72 and connects the battery 60 to the power supply terminal TP.

[0051] The bypass relay 76 is a normally closed relay. The bypass relay 76 is constituted by connecting switch elements SW7 and SW8 in series. The switch elements SW7 and SW8 are P-channel field effect transistors. The body diodes of the switch element SW7 and the body diode of the switch element SW8 are connected to each other at their anodes. Voltages from pre-drivers 78 and 80 are applied to the gates of the switch elements SW7 and SW8.

[0052] The pre-driver 78 uses the capacitor 82 as a power supply. The pre-driver 78 opens and closes the bypass relay 76 by generating a potential difference between the gate and the source, or between the gate and the drain of the switch elements SW7 and SW8. The pre-driver 78 includes a circuit that switches which of the two, the negative electrode of the capacitor 82 and a portion at a higher potential than the negative electrode, is connected to the gates of the switch elements SW7 and SW8. Here, the portion at a higher potential may be the positive electrode of the capacitor 82. Additionally, the portion at a higher potential may be a portion at a higher potential than the positive electrode of the capacitor 82. A portion at a higher potential than the positive electrode of the capacitor 82 can be realized, for example, by a charge pump that the pre-driver 78 has to boost the charging voltage of the capacitor 82.

[0053] The pre-driver 80 uses the battery 60 as a power supply. The pre-driver 80 opens and closes the bypass relay 76 by generating a potential difference between the gate and the source, or between the gate and the drain of the switch elements SW7 and SW8. The pre-driver 80 includes a circuit that switches which of the two, the negative electrode of the battery 60 and a portion at a higher potential than the negative electrode, is connected to the gates of the switch elements SW7 and SW8. Here, the portion at a higher potential may be the positive electrode of the battery 60. Additionally, the portion at a higher potential may be a portion at a higher potential than the positive electrode of the battery 60. A portion at a higher potential than the positive electrode of the battery 60 can be realized, for example, by a charge pump that the pre-driver 80 has to boost the terminal voltage of the battery 60.

[0054] The charging voltage of the capacitor 82 is applied to the second power conversion circuit 84. The second power conversion circuit 84 is a circuit that boosts the charging voltage of the capacitor 82. Specifically, the second power conversion circuit 84 is a boost chopper circuit. Specifically, the second power conversion circuit includes an inductor 84a connected to the input terminal, and a diode 84b whose anode is connected to the inductor 84a. The cathode of the diode 84b is the output terminal of the second power conversion circuit 84. The anode of the diode 84b is connected to the ground terminal TG via the switching element SW9.

[0055] A capacitor 85 is provided between the output terminal of the second power conversion circuit 84 and the ground terminal TG.

[0056] The output voltage of the second power conversion circuit 84 and the applied voltage to the power supply terminal TS are input to the OR circuit 86. The OR circuit 86 outputs the logical sum voltage of the input voltages. That is, the OR circuit 86 outputs the larger of the two input voltages when the two input voltages are not equal. The OR circuit 86 outputs the input voltage when the two input voltages are equal. In addition, the applied voltage to the power supply terminal TS is input to the OR circuit 86 via the power relay 74.

[0057] Specifically, the OR circuit 86 includes diodes 86a, 86b. The anode of the diode 86a is connected to the power supply terminal TS, and the cathode is connected to the control terminal TC. The anode of the diode 86b is connected to the output terminal of the second power conversion circuit 84, and the cathode is connected to the control terminal TC.

[0058] The control unit 88 as the processing circuit is hardware that uses the output voltage of the power supply circuit 70 as the control quantity. The control unit 88 can be configured to include, for example, a PU and a storage device. Here, the PU is a software processing device such as a CPU, GPU, and TPU. The storage device can also be a non-volatile memory that cannot be electrically rewritten. In addition, the storage device can also be a non-volatile memory that can be electrically rewritten, and a storage medium such as a disk medium. In addition, as the control unit 88, it is not limited to executing software processing. For example, the control unit 88 can also include a dedicated hardware circuit such as an ASIC.

[0059] The control unit 88 operates the switching elements SW1 to SW9 in order to control the output voltage of the power supply circuit 70.

[0060] "Operation of the power supply circuit 70"

[0061] In Figure 5 the operation of the power supply circuit 70 is shown.

[0062] In Figure 5An example where the IG signal is turned on at time t1 is shown. In other words, a situation where the driving permission signal is turned on, that is, a state indicating driving permission, is shown. After the IG signal becomes the on state, at time t2, the control unit 88 becomes the on state. When the control unit 88 becomes the on state, first, at time t3, the power relay 74 is turned on. Moreover, the control unit 88 starts driving the first power conversion circuit 72 and the second power conversion circuit 84 at time t4.

[0063] After the battery 60 is normal, the control unit 88 outputs the power of the battery 60 via the first power conversion circuit 72 through the process shown in FIG. 3. When the control unit 88 does not apply an abnormal voltage such as the terminal voltage of the battery 60 to the power supply terminal TS or when the battery 60 cannot supply power sufficiently, the control unit 88 outputs the power of the capacitor 82 via the first power conversion circuit 72 through the process shown in FIG. 4.

[0064] As Figure 6 shown, the control unit 88 sets the command value Vout2* of the output voltage Vout2 of the second power conversion circuit 84 to a value lower than the terminal voltage VB of the battery 60. Therefore, when the terminal voltage VB of the battery 60 is applied to the power supply terminal TS, the OR circuit 86 outputs the voltage applied to the power supply terminal TS. That is, in this case, the power output from the OR circuit 86 is the output power of the battery 60, so the power consumption of the capacitor 82 can be suppressed.

[0065] Return Figure 5 , the control unit 88 switches the bypass relay 76 to the off state at time t5. In other words, the bypass relay 76 is switched to the state.

[0066] <Function and Effect of the Present Embodiment>

[0067] Here, the function and effect of the present embodiment will be described.

[0068] The power of the battery 60 and the charging power of the capacitor 82 are input to the first power conversion circuit 72. Therefore, even if an abnormality occurs in the battery 60, for example, the charging power of the capacitor 82 can be supplied to the reaction force control unit 40 and the steering control unit 50.

[0069] Here, the first power conversion circuit 72 shares the switching elements SW1 to SW4 in the circuit part taking the battery 60 as the input and the circuit part taking the capacitor 82 as the input. Therefore, it helps to reduce the number of components.

[0070] However, when an abnormality occurs in the switching elements SW1 to SW4, it may not be possible to supply the power of the battery 60 and the charging power of the capacitor 82 to the reaction force control unit 40 and the steering control unit 50.

[0071] Therefore, a bypass relay 76 is provided in the power supply circuit 70. The bypass relay 76 bypasses the first power conversion circuit 72 and connects the positive electrode of the battery 60 to the power supply terminal TP. Therefore, even when the first power conversion circuit 72 does not operate normally, the power of the battery 60 can be supplied to the reaction force inverter 18 and the steering inverter 36.

[0072] According to the present embodiment described above, the following operations and effects can also be obtained.

[0073] (1-1) The bypass relay 76 is set as a normally closed relay. Thus, after the IG signal is switched to the ON state, power can be quickly supplied to the reaction force inverter 18 and the steering inverter 36.

[0074] That is, as Figure 5 shown, when the IG signal is switched to the ON state, after the power supply relay 74 is closed, the first power conversion circuit 72 is driven. Therefore, after the IG signal is switched to the ON state, there is a delay until the output voltage of the first power conversion circuit 72 is applied to the reaction force inverter 18 and the steering inverter 36. Therefore, in the present embodiment, the bypass relay 76 is set as a normally closed type. Thus, when the IG signal is switched, the terminal voltage of the battery 60 is applied to the reaction force power supply relay 46. In addition, when the IG signal is switched, the terminal voltage of the battery 60 is applied to the steering power supply relay 56. Therefore, if the IG signal is switched, the terminal voltage of the battery 60 can be applied to the reaction force inverter 18 and the steering inverter 36 via the bypass relay 76 as early as possible.

[0075] (1-2) The bypass relay 76 is composed of a series connection body of a pair of switching elements SW7 and SW8, and the forward directions of these body diodes are opposite to each other. Thus, in the open state of the bypass relay 76, current flowing between the battery 60 and the power supply terminal TP via the body diode can be suppressed.

[0076] (1-3) The drive circuits of the bypass relay 76 are set as pre-drivers 78 and 80 with different power supplies. Thus, even if an abnormality occurs in either the battery 60 or the capacitor 82, the bypass relay 76 can be operated.

[0077] (1-4) The negative electrode of the battery 60 is connected to the reaction force control unit 40 and the steering control unit 50 via a ground wiring LG that bypasses the housing Ha of the power supply circuit 70. Thereby, the number of terminals of the connector of the power supply circuit 70 can be reduced. That is, when a terminal connected to the ground terminal TG is provided in the power supply circuit 70 and the negative electrode of the battery 60 is connected to the reaction force control unit 40 and the steering control unit 50 via this terminal, the number of terminals of the power supply circuit 70 increases.

[0078] Moreover, the restriction related to the flow path cross-sectional area of the ground wiring LG is looser than the restriction related to the flow path cross-sectional area of the wiring within the power supply circuit 70. Therefore, the resistance between the negative electrode of the battery 60 and the reaction force control unit 40 and the steering control unit 50 can be reduced. Therefore, the utilization efficiency of electric power can be improved.

[0079] (1-5) Electric power of the battery 60 and electric power of the capacitor 82 can be supplied to the control terminal TC. Thereby, even if an abnormality occurs in either the battery 60 or the capacitor 82, electric power can be supplied to the reaction force control unit 40 and the steering control unit 50 via the control terminal TC.

[0080] (1-6) The output voltage of the second power conversion circuit 84 that boosts the charging power of the capacitor 82 can be output to the control terminal TC. Thereby, even when the charging voltage of the capacitor 82 is low, a required voltage can be applied to the control terminal TC.

[0081] (1-7) Even when not using the electric power of the capacitor 82, the control unit 88 can control the output voltage of the second power conversion circuit 84 to a voltage lower than the terminal voltage of the battery 60 and drive the second power conversion circuit 84. Thereby, when an abnormality occurs in the battery 60, resetting of the reaction force microcomputer 44 and the steering microcomputer 54 can be suppressed.

[0082] That is, when the second power conversion circuit 84 is stopped in advance without using the electric power of the capacitor 82, at the time of an abnormality where the terminal voltage of the battery 60 is no longer applied to the power supply terminal TS, etc., the voltage of the control terminal TC temporarily drops significantly. Therefore, the reaction force microcomputer 44 and the steering microcomputer 54 may be reset. Therefore, in the present embodiment, by driving the second power conversion circuit 84 in advance, when the terminal voltage of the battery 60 is not applied to the power supply terminal TS, the output voltage of the second power conversion circuit 84 is immediately applied to the control terminal TC. Therefore, the operating states of the reaction force microcomputer 44 and the steering microcomputer 54 can be continued.

[0083] (1-8) A power relay 74 is provided between the battery 60 and the first power conversion circuit 72. Thereby, it is possible to suppress the power of the battery 60 from flowing out to the power supply terminal TP via the first power conversion circuit 72 when the first power conversion circuit 72 stops. That is, when the power relay 74 is not provided, when the first power conversion circuit 72 stops, current may flow from the positive electrode of the battery 60 to the power supply terminal TP via the body diodes of the switching elements SW1 and SW2.

[0084] (1-9) The power relay 74 is composed of two switching elements SW5 and SW6 whose body diodes are connected in reverse to each other. Thereby, when the first power conversion circuit 72 stops, in both cases where the battery 60 is correctly connected and where it is connected with the opposite polarity, it is possible to suppress the current from the battery 60 from flowing through the body diodes of the first power conversion circuit 72. That is, when the battery 60 is connected with the opposite polarity, in the path including the switching elements SW3 and SW4, the first inductor 72a, and the battery 60, the body diodes of the switching elements SW3 and SW4 become forward. Therefore, when the loop path cannot be opened by the power relay 74, the loop path becomes a closed loop state.

[0085] <Second Embodiment>

[0086] Hereinafter, the second embodiment will be described with reference to the drawings centering on the differences from the first embodiment.

[0087] In Figure 7 and Figure 8 show the structure of the power supply system according to this embodiment. In addition, in Figure 7 and Figure 8 for convenience, the same reference numerals are given to the components corresponding to the components shown in Figure 1 and Figure 2

[0088] As shown in Figure 7 and Figure 8 the negative terminal of the battery 60 is connected to the reaction force control unit 40 and the steering control unit 50 via two ground wirings LG respectively. That is, the electrical path of the ground potential between the battery 60 and the reaction force control unit 40 and the steering control unit 50 is made redundant. Thereby, it is possible to more stably supply the ground potential to the reaction force control unit 40 and the steering control unit 50 respectively.

[0089] Moreover, when the ground terminal TG and the negative electrode of the battery 60 are in a disconnected state, power can be supplied to the reaction force control unit 40 and the steering control unit 50 more reliably. That is, the loop path including the bypass relay 76, the reaction force inverter 18 (steering inverter 36), the ground wiring LG, and the battery 60 can be made into a closed loop more reliably. In addition, the path including the battery 60, the power supply terminal TS, the control terminal TC, the reaction force microcomputer 44 (steering microcomputer 54), and the ground wiring LG can be made into a closed loop more reliably.

[0090] In addition, the power supply circuit 70 includes two power supply terminals TP. Specifically, as Figure 8 shown, the output terminal of the first power conversion circuit 72 is connected to two different power supply terminals TP. In addition, the bypass relay 76 is also connected to two different power supply terminals TP. Moreover, the two power supply terminals TP are respectively connected to the reaction force control unit 40 and the steering control unit 50. That is, the circulation paths of the output power of the battery 60 and the first power conversion circuit 72 between the power supply circuit 70 and the reaction force control unit 40 and the steering control unit 50 are redundant. Thereby, the output power of the battery 60 and the first power conversion circuit 72 can be supplied to the reaction force control unit 40 and the steering control unit 50 more stably.

[0091] In addition, the power supply circuit 70 includes two control terminals TC. Specifically, as Figure 8 shown, the power supply circuit 70 includes two OR circuits 86. The voltages of the power supply terminal TS and the output voltage of the second power conversion circuit 84 are applied to these OR circuits 86. Moreover, the output voltages of the two OR circuits 86 are respectively connected to different control terminals TC.

[0092] Moreover, the two control terminals TC are respectively connected to the reaction force control unit 40 and the steering control unit 50. That is, the circulation paths of the output power of the battery 60 and the capacitor 82 between the power supply circuit 70 and the reaction force control unit 40 and the steering control unit 50 are redundant. Thereby, the output power of the battery 60 and the capacitor 82 can be supplied to the reaction force control unit 40 and the steering control unit 50 more stably.

[0093] <Other Embodiments>

[0094] In addition, this embodiment can be implemented with the following changes. This embodiment and the following modification examples can be implemented in combination with each other within a range where there is no technical contradiction.

[0095] "Regarding the switch"

[0096] · As the switch, it is not limited to two P-channel field effect transistors whose body diodes' anodes are connected to each other. For example, the switch can also be two P-channel field effect transistors whose body diodes' cathodes are connected to each other.

[0097] · As the voltage-controlled switch element that constitutes the switch, it is not limited to P-channel field effect transistors. For example, it can also be N-channel field effect transistors. In this case, for example, as long as the path that opens and closes the path connecting the gate of the N-channel field effect transistor to the positive terminal of the battery 60 is constituted by a P-channel field effect transistor. Thus, the switch can be made into a normally-closed type.

[0098] · It is also possible not to short-circuit the conduction control terminals of the two voltage-controlled switch elements that constitute the switch. In this case, for example, it is also possible to start the drive of the first power conversion circuit 72 and selectively perform a turn-off operation on the switch element that has a body diode with the forward direction being the direction from the battery 60 to the power supply terminal TP. In this case, for the switch element that has a body diode with the reverse direction being the direction from the battery 60 to the power supply terminal TP, as long as the turn-off operation is performed after the output of the first power conversion circuit 72 stabilizes.

[0099] · The switch does not have to be constituted by two voltage-controlled switch elements. For example, the switch can also be constituted by a series connection of three or more voltage-controlled switch elements. In this case, there may be cases where the forward directions of the body diodes are different. Additionally, for example, it can also be constituted by a single voltage-controlled switch element. Here, as the single voltage-controlled switch element that constitutes the switch, for example, an insulated gate bipolar transistor can also be used. Additionally, for example, as the single voltage-controlled switch element that constitutes the switch, a P-channel field effect transistor can also be used. Specifically, for example, the bypass relay 76 can also be constituted only by the switch element SW7. In this case, for example, a voltage-controlled switch element can also be provided between the node N1 and the output terminal of the first power conversion circuit 72. Regarding the body diode of this switch element, the cathode can also be connected to the output terminal of the first power conversion circuit 72.

[0100] · The switch element that constitutes the switch does not have to be a voltage-controlled switch element. For example, it can also be a current-controlled switch element like a bipolar transistor.

[0101] · As the semiconductor element that constitutes the switch, it is not limited to transistors. For example, it can also be a thyristor.

[0102] · The switch does not have to be constituted by semiconductor elements. For example, it can also be configured to include an electromagnetic relay. In this case, it is also preferable to use a normally-closed electromagnetic relay.

[0103] · The switch is not necessarily of the normally - closed type.

[0104] "Regarding the drive circuit of the switch"

[0105] · Instead of connecting the terminal of the pre - driver 78 to the connection point of the switching elements SW3 and SW4, it can also be connected to the ground terminal TG.

[0106] · As the drive circuit of the switch, it is not limited to the pre - driver 78 with the capacitor 82 as the power source and the pre - driver 80 with the battery 60 as the power source. For example, as the drive circuit, it can also have either the pre - driver 78 or 80.

[0107] "Regarding the power relay"

[0108] · As the power relay, it is not limited to the two N - channel field - effect transistors with the anodes of the body diodes connected to each other as exemplified in the power relay 74. The switch can also be, for example, two N - channel field - effect transistors with the cathodes of the body diodes connected to each other.

[0109] · As the voltage - controlled switching element constituting the power relay, it is not limited to the N - channel field - effect transistor. For example, it can also be a P - channel field - effect transistor. In this case, for example, as long as the path for opening and closing the path connecting the gate of the P - channel field - effect transistor to the positive terminal of the battery 60 is constituted by a P - channel field - effect transistor, the switch can be made of the normally - open type.

[0110] · The power relay does not necessarily have to be composed of two voltage - controlled switching elements. For example, the power relay can also be composed of a series connection of three or more voltage - controlled switching elements. In this case, there are cases where the forward directions of the body diodes are different. Additionally, for example, it can also be composed of a single voltage - controlled switching element. Here, as the single voltage - controlled switching element constituting the power relay, for example, an insulated - gate bipolar transistor can also be used.

[0111] · The switching element constituting the power relay does not necessarily have to be a voltage - controlled switching element. For example, it can also be a current - controlled switching element like a bipolar transistor.

[0112] · As the semiconductor element constituting the power relay, it is not limited to transistors. For example, it can also be a thyristor.

[0113] · The power relay does not necessarily have to be composed of semiconductor elements. For example, it can also be configured to include an electromagnetic relay. In this case, it is also preferable to use a normally - open electromagnetic relay.

[0114] "Regarding the first power conversion circuit"

[0115] · The switching elements SW1 to SW4 constituting the first power conversion circuit 72 do not necessarily have to be field effect transistors. For example, they can also be insulated gate bipolar transistors. In this case, a freewheeling diode can also be connected in parallel with the switching elements SW1 to SW4.

[0116] · The first power conversion circuit 72 does not necessarily have to have four switching elements SW1 to SW4. For example, the first power conversion circuit 72 can also be a circuit in which the above-mentioned switching element SW1 is replaced with a diode. In this case, the circuit part of the first power conversion circuit 72 that takes the power of the battery 60 as input becomes a boost chopper circuit that takes the power of the battery 60 as input. In addition, in this case, the circuit part of the first power conversion circuit 72 that takes the power of the capacitor 82 as input becomes a boost chopper circuit that takes the power of the capacitor 82 as input.

[0117] · The supply destination of the output power of the first power conversion circuit is not limited to the actuator system. For example, it can also be supplied to the control system.

[0118] "Regarding the second power conversion circuit"

[0119] · The second power conversion circuit 84 does not necessarily have to be a boost chopper circuit. The second power conversion circuit 84 can also be, for example, a buck-boost chopper circuit. In addition, for example, the second power conversion circuit 84 can also be a charge pump.

[0120] "Regarding the electrical path bypassing the housing Ha of the power supply circuit"

[0121] · As the electrical path bypassing the housing Ha of the power supply circuit 70, it is not limited to one or two ground wirings LG. For example, it can also be three or more ground wirings LG.

[0122] "Regarding the first DC voltage source"

[0123] · The first DC voltage source does not necessarily have to be the battery 60. For example, it can also be a capacitor. However, in this case, it is preferable that the capacitor is provided between the output terminal of the power conversion circuit connected to the secondary battery and the ground. Thereby, the capacitor can charge the power of the secondary battery. In addition, this secondary battery can be, for example, a secondary battery that supplies power to the main unit mounted on an electric vehicle.

[0124] "Regarding the second DC voltage source"

[0125] · As the capacitor 82, it is not limited to a lithium ion capacitor. For example, it can also be an aluminum electrolytic capacitor or the like.

[0126] · The second DC voltage source does not have to be the capacitor 82. For example, it can also be a secondary battery.

[0127] · The full charge amount of the second DC voltage source does not have to be less than the full charge amount of the first DC voltage source.

[0128] · The terminal voltage of the second DC voltage source does not have to be less than the terminal voltage of the first DC voltage source.

[0129] "Regarding the electrical load of the power system"

[0130] · As the electrical load of the power system, it is not limited to the reaction force inverter 18 and the steering inverter 36. For example, in a structure capable of transmitting the power of the steering wheel 12 to the steering wheel 30, the drive circuit of an auxiliary motor that generates a torque for assisting the operation of the steering wheel 12 can also be used as the electrical load.

[0131] · The electrical load of the power system does not have to be the electrical load provided by the actuator of the vehicle's steering control system.

[0132] "Other"

[0133] · The power supply circuit 70 does not have to be equipped with a smoothing capacitor 73.

Claims

1. A power supply circuit, wherein, Comprising: A power conversion circuit configured to apply an output voltage to an electrical load; And A bypass path, The above power conversion circuit is configured to be applied with the terminal voltage of a first DC voltage source and the terminal voltage of a second DC voltage source, and includes a first inductor, a second inductor, and a plurality of switching elements, The plurality of above switching elements are configured to open and close a first loop path, a second loop path, a third loop path, and a fourth loop path respectively, The plurality of above switching elements that open and close the above first loop path and the above second loop path and the plurality of above switching elements that open and close the above third loop path and the above fourth loop path are common elements, The above first loop path is a path that includes the above first DC voltage source and the above first inductor and does not include the output terminal of the above power conversion circuit, The above second loop path is a path that includes the above first DC voltage source, the above first inductor, and the output terminal of the above power conversion circuit, The above third loop path is a path that includes the above second DC voltage source and the above second inductor and does not include the output terminal of the above power conversion circuit, The above fourth loop path is a path that includes the above second DC voltage source, the above second inductor, and the output terminal of the above power conversion circuit, The above bypass path is a path that bypasses the above power conversion circuit and connects the above first DC voltage source and the above electrical load, and includes a switch for opening and closing this bypass path.

2. The power supply circuit according to claim 1, wherein The above switch is a normally closed switch.

3. The power supply circuit according to claim 1, wherein The above switch is a voltage-controlled switching element, The above power supply circuit includes a drive circuit for driving the above switch, The above drive circuit uses both the above first DC voltage source and the above second DC voltage source as power supplies.

4. The power supply circuit according to claim 1, wherein A control unit is provided, The above control unit is configured to perform a process of switching the above switch to an open state after starting the drive of the above power conversion circuit.

5. The power supply circuit according to claim 4, wherein A power relay is provided, The above power relay is configured to open and close between the above first DC voltage source and the above power conversion circuit, The above control unit is configured to perform a process of driving the above power conversion circuit after making the above power relay in a closed state.

6. The power supply circuit according to claim 1, wherein Body diodes are respectively formed in the plurality of above switching elements with the direction advancing from the positive electrode of the above first DC voltage source to the above electrical load as the forward direction, The above power supply circuit includes a power relay, The above power relay is a relay for opening and closing between the above first DC voltage source and the above power conversion circuit.

7. A power supply system, wherein It includes the power supply circuit according to claim 1 and the above electrical load, The above power supply circuit and the above electrical load are housed in mutually different cases, The above power supply system has an electrical path that bypasses the housing containing the above power supply circuit and connects the negative electrode of the above first DC voltage source to the above electrical load.

8. The power supply system according to claim 7, wherein it has a plurality of electrical paths that bypass the housing containing the above power supply circuit and are connected.

9. The power supply system according to claim 7, wherein the above switch is connected to the above electrical load via a plurality of electrical paths outside the housing containing the above power supply circuit.

10. The power supply system according to claim 7, wherein this power supply system is mounted on a vehicle, in the above vehicle, the following processing is performed: in a state where the power transmission between the steering wheel and the steering wheel is cut off, the above steering wheel is operated according to the operation of the above steering wheel, the above electrical load includes a reaction force motor and a steering motor, the above reaction force motor is configured to apply a force that resists the rotation of the above steering wheel, the above steering motor is configured to steer the above steering wheel.

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