On-board charger and on-board charging system

Abstract

To provide an in-vehicle charger capable of AC normal charging by a general external power supply system even if an abnormality such as run-out of a low voltage battery occurs.SOLUTION: In an in-vehicle charger 10A of EV 100A, a control power supply circuit 15 is activated by a reserve DC power supplied from an AC / DC conversion / control power supply circuit 22 that converts an AC voltage of an AC power source 1 into a reserve DC voltage DC4 that is less than or more than a voltage value of a DC low voltage DC3 of a low voltage battery 12. The control power supply circuit 15 supplies power to a micro-controller unit 16, and a power conversion voltage generating unit driven by a driving circuit 17 controlled by the micro-controller unit 16 converts an AC voltage into a DC voltage DC1 and then into a DC high voltage DC2 used for high voltage application. Consequently, a high voltage battery 11 can be charged with the DC high voltage DC2 supplied from the power conversion voltage generating unit, regardless of a charged state of the low voltage battery 12.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an on-board charger and an on-board charging system that are mounted on electrically powered vehicles such as electric vehicles (hereinafter referred to as EVs) and PHEVs (plug-in hybrid vehicles) that are equipped with a high-voltage battery and a low-voltage battery. [Background technology]

[0002] Conventionally, this type of electric vehicle is equipped with a high-voltage battery, which is a direct current (DC) high-voltage storage battery for driving a motor that is a power source for traveling, and a low-voltage battery, which is a DC low-voltage storage battery for operating auxiliary machinery.

[0003] When the vehicle is running, the high-voltage battery consumes power and the charging rate decreases. The high-voltage battery can be charged using AC voltage from an AC (alternating current) power source supplied from an external power supply system by an on-board charger. Charging the high-voltage battery using this AC power source supplied from an external power supply system is generally called AC normal charging.

[0004] In addition, the low-voltage battery operates various auxiliary devices, including important safety devices such as contactors that operate to prevent electric shock from the high-voltage battery in the event of an accident. Therefore, the low-voltage battery needs to be charged in the same way as the high-voltage battery. In electric vehicles, the low-voltage battery is charged by converting the power stored in the high-voltage battery.

[0005] The power used to control the on-board charger is supplied from the low-voltage battery. Therefore, if an electric vehicle is left unused for a long period of time and the charging rates of both the high-voltage battery and the low-voltage battery drop, causing both the high-voltage battery and the low-voltage battery to be in a dead battery state, the on-board charger cannot operate because power cannot be supplied from the low-voltage battery, and normal AC charging is not possible. As a result, the high-voltage battery state cannot be resolved. Furthermore, because the high-voltage battery state cannot be resolved, the low-voltage battery cannot be charged.

[0006] Therefore, when both the high-voltage battery and the low-voltage battery are in a dead battery state, the dead battery state of the high-voltage battery and the low-voltage battery cannot be eliminated by the on-board charger.

[0007] In such a case, as in the case of a typical internal combustion vehicle, the low voltage battery is replaced or the low voltage battery is charged from the outside using a booster cable.

[0008] Incidentally, a well-known technique relating to charging a dead low-voltage battery is the "battery charging control device for an electric vehicle" (see Patent Document 1) which is capable of charging a dead auxiliary battery. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2019-170129 A Summary of the Invention [Problem to be solved by the invention]

[0010] In the case of the technology according to the above-mentioned Patent Document 1, when the auxiliary battery is not working, power is supplied from the charging box via the charging connector using a connector connection signal line that detects that the charging connector is connected to the electric vehicle, for controlling the on-board charger. However, the charging connector and charging box disclosed in Patent Document 1 have different electrical specifications from general charging connectors and charging boxes. Therefore, the technology according to Patent Document 1 has a problem in that a dedicated external power supply system is required. Note that the auxiliary battery here refers to a low-voltage battery.

[0011] The present invention has been made to solve these problems, and an object of the present invention is to provide an on-board charger and an on-board charging system that can perform normal AC charging using a general external power supply system even if an abnormality such as a low-voltage battery running out occurs. [Means for solving the problem]

[0012] One embodiment of an on-board charger for achieving the above-mentioned object is an on-board charger that charges a high-voltage battery mounted on the vehicle, and includes a first power conversion unit that converts power from an AC power source outside the vehicle into a first power for charging the high-voltage battery, a second power conversion unit that converts power from the external power source into a second power for controlling the first power conversion unit, and a selection unit that supplies either the second power or the power output from a low-voltage battery to a control unit of the first power conversion unit.

[0013] Furthermore, the voltage of the second power may be less than or greater than the voltage of the power output from the low voltage battery.

[0014] Moreover, the control unit may input a stop signal to the second power conversion unit, and the second power conversion unit may be activated until the stop signal is input.

[0015] Furthermore, the control unit may operate the first power conversion unit using the second power when a voltage of the power output from the low-voltage battery to the control unit is equal to or lower than a first predetermined voltage.

[0016] Furthermore, if the voltage of the second power is not a second predetermined voltage, the control unit: The stop signal may be input to the second power conversion unit, and the first power conversion unit may be operated using power output from the low-voltage battery to the control unit.

[0017] In addition, the control unit may determine whether the mode is normal or periodic diagnosis mode, and if the mode is normal, input the stop signal to the second power conversion unit and operate the first power conversion unit using power output from the low-voltage battery to the control unit.

[0018] One embodiment of an in-vehicle charging system for achieving the above-mentioned object includes an in-vehicle charger, in which a voltage of the second power exceeds a voltage output from the low-voltage battery, and the in-vehicle charger includes an activation signal input unit that inputs a signal to activate the second power conversion unit from outside the in-vehicle charger. Effect of the Invention

[0019] An on-board charger according to one or another aspect of the present invention converts the AC voltage of an external AC power source into a second power that is less than or exceeds the voltage value of a low-voltage battery, and supplies the second power to a control unit. As a result, even if a state occurs in the low-voltage battery, the control unit activated by the second power can charge the high-voltage battery. As a result, even if the low-voltage battery is in an abnormal state, the high-voltage battery can be charged, and then the low-voltage battery can also be charged, making it possible to provide redundancy with the conductive wire of the low-voltage battery. Also, the charging system of the on-board charger according to the other aspect described above can provide similar effects. [Brief description of the drawings]

[0020] [Figure 1] This is a block diagram showing the basic configuration of an EV equipped with a typical on-board charger, including the peripheral configuration. [Diagram 2] FIG. 1 is a block diagram showing the basic configuration of an EV equipped with an on-board charger according to a first embodiment of the present invention, including the peripheral configuration. [Diagram 3] FIG. 11 is a block diagram showing the basic configuration of an EV equipped with an on-board charger according to a second embodiment of the present invention, including the peripheral configuration. [Figure 4] FIG. 11 is a block diagram showing the basic configuration of an EV equipped with an on-board charger according to a third embodiment of the present invention, including the peripheral configuration. [Diagram 5] 5 is a flowchart showing operational processing relating to charging by activating each part of the EV shown in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an on-board charger and an on-board charger system according to the present invention will be described in detail with reference to several embodiments and the accompanying drawings.

[0022] First, in order to facilitate understanding of the technical gist of the on-board charger of the present invention, the basic configuration and functions of a well-known, general on-board charger will be described assuming that it is mounted on an EV.

[0023] FIG. 1 is a block diagram showing the basic configuration of an EV 100 equipped with a typical on-board charger 10, including the peripheral configuration.

[0024] Referring to FIG. 1, the EV 100 has an external charging cable connection unit 3 at a location facing the outside for connecting a charger 2 connected to an AC power source 1, which is an external peripheral component. The AC power source 1 may be installed in a home or the like. The charger 2 may be considered as a charging station installed on the ground. Note that a charging facility consisting of the AC power source 1, the charger 2, and the external charging cable connection unit 3 is an example of a general external power supply system. The EV 100 also includes a high-voltage battery 11 for DC high voltage and a low-voltage battery 12 for DC low voltage, and is capable of charging the high-voltage battery 11 using the AC voltage of the AC power source 1 by an on-board charger 10 described later. Note that the AC voltage from the AC power source 1 is taken into the EV 100 via the charger 2 and the external charging cable connection unit 3.

[0025] The on-board charger 10 includes a control power supply circuit 15, a microcontroller unit (MCU) 16, a drive circuit (driver) 17, an AC / DC converter (AC / DC1) 19, and a DC / DC converter (DC1 / DC2) 18. That is, in the EV 100 shown in FIG. 1 , the on-board charger 10 is configured by the control power supply circuit 15, the microcontroller unit 16, the drive circuit 17, the DC / DC converter 18, and the AC / DC converter 19. Of these, the control power supply circuit 15, the microcontroller unit 16, and the drive circuit 17 can be considered as a control unit that controls charging to the high-voltage battery 11. The EV 100 includes electronic control units (ECU1) 13 and (ECU2) 14 that are driven by a DC low voltage from the low-voltage battery 12, a DC / DC converter (DC2 / DC3) 20, and the on-board charger 10. Of these, the number of electronic control units (ECU1) 13, (ECU2) 14 is not limited to the illustrated case, and a large number may be provided. The DC / DC converter 20 is connected to the high-voltage battery 11 and the DC / DC converter 18. The DC / DC converter 18 is further connected to the external charging cable connection unit 3 and an AC / DC converter 19. In the on-board charger 10, the control power supply circuit 15 is driven by a DC low voltage from the low-voltage battery 12. The DC / DC converter 20 can charge the low-voltage battery 12 with power from the high-voltage battery 11.

[0026] In this EV 100, if the low-voltage battery 12 is normal, the low-voltage battery 12 applies a DC low voltage DC3 in the on-board charger 10, and the control power supply circuit 15 starts up. Then, the control power supply circuit 15 supplies power to the microcontroller unit 16 to perform control, and charges the high-voltage battery 11. At this time, the microcontroller unit 16 controls the drive circuit 17, and the AC / DC converter 19 driven by the drive circuit 17 converts the AC voltage from the external AC power source 1 into a DC voltage DC1.

[0027] Furthermore, the microcontroller unit 16 controls the drive circuit 17, and the DC / DC converter 18 driven by the drive circuit 17 converts the DC voltage DC1 into a DC high voltage DC2 for high voltage application. Then, the high voltage battery 11 is charged using the DC high voltage DC2 for high voltage application. The AC / DC converter 19 and the DC / DC converter 18 here function as a power conversion voltage generating unit that converts the AC voltage into the DC voltage DC1 and also converts the DC voltage DC1 into the DC high voltage DC2. That is, the AC / DC converter 19 generates the DC voltage DC1 from the AC voltage, and the DC / DC converter 18 generates the DC high voltage DC2 from the DC voltage DC1.

[0028] However, as has been raised as a problem, this EV 100 does not have a backup function when the low-voltage battery 12 does not work due to an abnormality, so even if the external charging cable connection part 3 is connected to the on-board charger 10, power is not supplied from the low-voltage battery 12 to the microcontroller unit 16, and the on-board charger 10 cannot be started. Therefore, with the configuration in Figure 1, it is not possible to charge the high-voltage battery 11 when the low-voltage battery 12 does not work due to an abnormality. In addition, from the above, it can be said that the configuration in Figure 1 that does not have a backup function does not provide sufficient redundancy with the conductive wires of the low-voltage battery 12.

[0029] (Embodiment 1) FIG. 2 shows a first embodiment of the present invention. Referring to FIG. 2, the EV 100A of the present invention, like the conventional EV 100 shown in FIG. 1, has an external charging cable connection unit 3 at a location facing the outside for connecting a charger 2 connected to an AC power source 1, which is an external peripheral component. Note that an external power supply system consisting of the AC power source 1, the charger 2, and the external charging cable connection unit 3 is an example of an external power source in the claims. Note that the external power supply system is similar to the general external power supply system described above. Also, like the conventional EV 100, the EV 100A includes a high-voltage battery 11 for DC high voltage and a low-voltage battery 12 for DC low voltage, and the high-voltage battery 11 can be charged using the AC power source 1 by an on-board charger 10A described later.

[0030] The vehicle-mounted charger 10A of the present invention in FIG. 2, like the conventional vehicle-mounted charger 10, is configured to include a control power supply circuit 15, a microcontroller unit (MCU) 16, a drive circuit (driver) 17, an AC / DC converter (AC / DC1) 19, and a DC / DC converter (DC1 / DC2) 18, as well as an AC / DC conversion / control power supply circuit (AC / DC4) 22, and diodes D1 and D2.

[0031] In the on-board charger 10A of the present invention, a circuit composed of the control power supply circuit 15, the microcontroller unit (MCU) 16, the drive circuit (driver) 17, the AC / DC converter (AC / DC1) 19, and the DC / DC converter (DC1 / DC2) 18 constitutes a power converter that controls the microcontroller unit (MCU) 16 supplied with power from the control power supply circuit 15 and the drive circuit (driver) 17 to control the AC / DC converter (AC / DC1) 19 and the DC / DC converter (DC1 / DC2) 18, as in the conventional on-board charger 10, converts the voltage of the AC power source 1 applied to the on-board charger 10A from the external charging cable connection unit 3 into a DC high voltage DC2, and charges the high voltage battery 11. The power converter composed of the control power supply circuit 15, the microcontroller unit (MCU) 16, the drive circuit (driver) 17, the AC / DC converter (AC / DC1) 19, and the DC / DC converter (DC1 / DC2) 18 is an example of a first power conversion unit in the claims. Moreover, a circuit configured from the control power supply circuit 15, the microcontroller unit (MCU) 16, and the drive circuit (driver) 17 is an example of a control unit in the claims.

[0032] The in-vehicle charger 10A of the present invention differs from the conventional in-vehicle charger 10 in that the AC / DC conversion and control power supply circuit 22 converts the voltage of the AC power source 1 applied to the in-vehicle charger 10A from the external charging cable connection part 3 into a standby DC voltage DC4 regardless of the state of the low-voltage battery 12. Furthermore, when an abnormality occurs in the low-voltage battery 12, the AC / DC conversion and control power supply circuit 22 is a circuit that applies the standby DC voltage DC4 to the control power supply circuit 15 via a diode D1 and supplies standby DC power to the control power supply circuit 15. The AC / DC conversion and control power supply circuit 22 is an example of a second power conversion part in the claims, and the standby DC power is an example of a second power in the claims.

[0033] The on-board charger 10A differs from the conventional on-board charger 10 in that the cathodes of the diodes D1 and D2 are both connected to the control power supply circuit 15, and the anodes are connected to a conductive line that applies a backup DC voltage DC4 from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15 and a conductive line that applies a DC low voltage DC3 from the low-voltage battery 12 to the control power supply circuit 15. This connection prevents reverse application of voltage to each power supply path, and also makes it possible to switch the power source that supplies power to the control power supply circuit 15 to the low-voltage battery 12 or the AC / DC conversion and control power supply circuit 22. In other words, the diodes D1 and D2 are an example of a selection unit in the claims. Note that the selection unit is not limited to a diode, and may be any element that can prevent reverse current flow. In order to further reduce power loss by the selection unit, an ORING MOSFET or the like may be used.

[0034] The EV 100A of the present invention includes an on-board charger 10A, a high-voltage battery 11, a low-voltage battery 12, and, like the conventional EV 100, electronic control units (ECU1) 13, (ECU2) 14, and a DC / DC converter (DC2 / DC3) 20. These devices are similar to those of the conventional EV 100, so a description thereof will be omitted.

[0035] To summarize the above, the EV100A of the present invention differs from the conventional EV100 in that the on-board charger is provided with an AC / DC conversion and control power supply circuit 22 and diodes D1 and D2. Due to this difference, even if an abnormality occurs in the low-voltage battery 12 and power cannot be supplied to the control power supply circuit 15, power is supplied from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15, making it possible to charge the high-voltage battery 11. A method for charging the high-voltage battery 11 of the present invention will be described below.

[0036] First, the operation when the low-voltage battery 12 is normal will be described in the charging operation of the high-voltage battery 11 using the AC power source 1 of the EV 100A of the present invention. In the first embodiment, the backup DC voltage DC4 is lower than the voltage (DC low voltage DC3) that the low-voltage battery 12 applies to the control power supply circuit 15.

[0037] In the EV 100A of the present invention, if the low-voltage battery 12 is normal, the low-voltage battery 12 applies a DC low voltage DC3 to the control power supply circuit 15 via the diode D2, and power is supplied to the control power supply circuit 15. The control power supply circuit 15, which receives power from the low-voltage battery 12, starts up and supplies power to the microcontroller unit 16. The microcontroller unit 16, which receives power from the control power supply circuit 15 and starts up, controls the drive circuit 17, AC / DC converter 19, and DC / DC converter 18, and converts the voltage of the external power source AC1 into a DC high voltage DC2. The microcontroller unit 16 then charges the high-voltage battery 11 using the DC high voltage DC2 for applying a high voltage.

[0038] At this time, the AC / DC conversion and control power supply circuit 22 is in an activated state, but since the standby DC voltage DC4 is lower than the DC low voltage DC3, the diode D1 is turned off. Therefore, no power is supplied from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15.

[0039] That is, in the first embodiment, when the low voltage battery 12 is normal, the operation is the same as that of the conventional EV 100, except that when power is supplied from the low voltage battery 12 to the control power supply circuit 15, it goes through the diode D2.

[0040] Next, a description will be given of the operation when an abnormality occurs in the low-voltage battery 12 during charging of the high-voltage battery 11 using the AC power source 1 of the EV 100A. In the first embodiment, the backup DC voltage DC4 is lower than the voltage (DC low voltage DC3) that the normal low-voltage battery 12 applies to the control power supply circuit 15.

[0041] In the on-board charger 10A, if an abnormality occurs in the low-voltage battery 12 and the DC low voltage DC3 drops, the backup DC voltage DC4 exceeds the DC low voltage DC3, the diode D1 is turned on, and the diode D2 is turned off. Therefore, the control power supply circuit 15 is started by the backup DC power supplied from the AC / DC conversion and control power supply circuit 22 through the diode D1, and supplies power to the microcontroller unit 16. The microcontroller unit 16, which is started by receiving power supply from the control power supply circuit 15, controls the drive circuit 17, the AC / DC converter 19, and the DC / DC converter 18, and converts the voltage of the external power supply AC1 into the DC high voltage DC2. Then, the microcontroller unit 16 charges the high-voltage battery 11 using the DC high voltage DC2 for applying a high voltage. As a result, even if the low-voltage battery 12 is in an abnormal state, the high-voltage battery 11 can be charged by the control of the started microcontroller unit 16.

[0042] As described above, in the on-board charger 10A, even if the low-voltage battery 12 is in an abnormal state, it is possible to charge the high-voltage battery 11, and then charge the low-voltage battery 12 as well. This allows redundancy with the conductive wires of the low-voltage battery 12. Charging of the low-voltage battery 12 is performed by operating the DC / DC converter 20 to which the DC high voltage DC2 is applied from the charged high-voltage battery 11. At this time, the DC / DC converter 20 converts the DC high voltage DC2 from the DC / DC converter 18 into a DC low voltage DC3 for low-voltage application, and charges the low-voltage battery 12 with the DC low voltage DC3.

[0043] Incidentally, the AC / DC conversion and control power supply circuit 22 in the on-board charger 10A may convert the AC voltage into a reserve DC voltage DC4 that exceeds the voltage value of the DC low voltage DC3. In this case, the control power supply circuit 15 is started by the reserve DC power supplied from the AC / DC conversion and control power supply circuit 22 via the diode D1, regardless of the state of the low-voltage battery 12. Note that the operation of charging the high-voltage battery 11 and the subsequent operation of charging the low-voltage battery 12 are performed in the same manner, and the effects are almost the same, so a description thereof will be omitted.

[0044] In short, it is sufficient if the backup DC voltage DC4 converted by the AC / DC conversion and control power supply circuit 22 and the backup DC power obtained by the conversion are capable of starting the control power supply circuit 15. In any case, unlike the case of the on-board charger 10, the on-board charger 10A has the special advantage that the high-voltage battery 11 can be charged even if the low-voltage battery 12 is not operating.

[0045] As described above, by setting the backup DC power supply DC4 lower than the DC low voltage DC3, when the low-voltage battery 12 is normal, it is possible to eliminate the power supply from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15. In other words, it is possible to suppress the power loss occurring in the AC / DC conversion and control power supply circuit 22, and to reduce the power loss when charging the high-voltage battery 11. In addition, since the frequency and period of use of the AC / DC conversion and control power supply circuit 22 can be reduced, it is possible to employ inexpensive components, and it is expected to be a low-cost circuit.

[0046] In contrast, a case is assumed in which the backup DC voltage DC4 is set higher than the DC low voltage DC3. In this case, even when the low-voltage battery 12 is normal, power is supplied from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15, and power loss increases compared to a case in which the backup DC voltage DC4 is set lower than the DC low voltage DC3. However, this allows for application to multiple functions. Such a configuration will be described below as a specific example with reference to several embodiments.

[0047] (Embodiment 2) FIG. 3 is a block diagram showing the basic configuration of an EV 100B equipped with an on-board charger 10B according to a second embodiment of the present invention, including the peripheral configuration.

[0048] 3, the EV 100B is different from the EV 100A in that the backup DC voltage DC4 is set higher than the low DC voltage DC3 of the low-voltage battery 12, and the configuration of the on-board charger is also partially different. That is, the on-board charger 10B of the EV 100B is different from the on-board charger 10A of the EV 100A in that a switch SW is connected to the AC / DC conversion and control power supply circuit 22 in the on-board charger 10B and arranged outside the vehicle (EV 100B) and is drawn out. This switch SW is capable of switching the operation of the AC / DC conversion and control power supply circuit 22 on and off. The other configurations are the same as those of the on-board charger 10A. The switch SW is an example of a start-up signal input unit in the claims.

[0049] As described above, in the EV 100B, the reserve DC voltage DC4 is set higher than the DC low voltage DC3. When the switch SW is turned on with this setting, the reserve DC voltage DC4 is higher than the DC low voltage DC3, so that the diode D1 is turned on and the diode D2 is turned off. As a result, even if the low-voltage battery 12 is normal, power is supplied from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15. Therefore, regardless of the state of the low-voltage battery 12, when the switch SW is turned on, power is supplied from the AC / DC conversion and control power supply circuit 22 to the control power supply circuit 15, the microcontroller unit 16 starts up, and the high-voltage battery 11 is charged with the DC high voltage DC2 generated from the AC voltage.

[0050] In the EV 100B, it is preferable to set the switch SW to be turned off so as not to operate the AC / DC conversion and control power supply circuit 22 after charging of the high-voltage battery 11 and the low-voltage battery 12 is completed. This is because power loss can be reduced by supplying power from the low-voltage battery 12 without power conversion, rather than via the AC / DC conversion and control power supply circuit 22, which requires power conversion to supply power to the control power supply circuit 15. For this reason, in the EV 100B, if the switch SW remains on during a period other than charging, it is preferable to detect this and provide a notification (such as an alarm display).

[0051] In the case of the EV 100B, if the voltage value of the backup DC voltage DC4 is set sufficiently higher than the voltage value of the DC low voltage DC3, the AC / DC conversion and control power supply circuit 22 can be used even if there is no abnormality in the low-voltage battery 12. In particular, since the operation of the AC / DC conversion and control power supply circuit 22 can be selected by operating an external switch SW, it is possible to confirm that the AC / DC conversion and control power supply circuit 22 is available for use when needed. In other words, periodic diagnosis of the AC / DC conversion and control power supply circuit 22 can be performed manually by the driver of the vehicle (EV 100B), etc. Periodic diagnosis can be, for example, daily inspection by the driver, 12-month inspection by a contractor, inspection at the time of vehicle inspection, etc.

[0052] In the EV 100B of the second embodiment, even if an abnormality occurs in the low-voltage battery 12, it is possible to charge the high-voltage battery 11, and then charge the low-voltage battery 12 as well. This allows for redundancy with the conductive wires of the low-voltage battery 12. In the case of the on-board charger 10B, as described above, regular diagnosis of the AC / DC conversion and control power supply circuit 22 can be performed manually, and this is a feature that differs from the EV 100A.

[0053] (Embodiment 3) FIG. 4 is a block diagram showing the basic configuration of an EV 100C equipped with an on-board charger 10C according to a third embodiment of the present invention, including the peripheral configuration.

[0054] 4, the EV100C differs from the EV100A in that the backup DC voltage DC4 is set higher than the DC low voltage DC3 of the low-voltage battery 12 when the battery is normal, and in that the microcontroller unit (MCU) 16 has a function of turning on and off the backup DC voltage DC4 applied to the AC / DC conversion and control power supply circuit 22. This makes it possible to switch between normal charging operation, periodic diagnostic operation, abnormality detection of the AC / DC conversion and control power supply circuit 22, and charging operation when an abnormality occurs in the low-voltage battery.

[0055] 5 is a flowchart showing the operational processing related to charging by activating each part of the EV 100C. However, in the on-board charger 10C of the EV 100C, the backup DC voltage DC4 of the AC / DC conversion and control power supply circuit 22 is designed to be sufficiently higher than the DC low voltage DC3 of the low-voltage battery 12. Note that the operational processing here is determined and carried out autonomously by the microcontroller unit 16.

[0056] 5, when charging starts, in step S501, DC4EN=ON (default) is adopted as the default (initial setting value) on the software program of the microcontroller unit 16. This DC4EN=ON indicates the meaning of starting up the AC / DC conversion and control power supply circuit 22 of the on-board charger 10C. By setting the default state of the AC / DC conversion and control power supply circuit 22 to ON in this way, it is possible to start up the microcontroller unit 16 regardless of the state of the low-voltage battery 12. Note that if an abnormality occurs in the AC / DC conversion and control power supply circuit 22 and it is not possible to output the backup DC voltage DC4, power is supplied from the low-voltage battery 12 to start up the microcontroller unit 16.

[0057] In step S502, the state transitions to AC / DC4 ON, which indicates that the operation of the AC / DC conversion·control power supply circuit 22 is turned on. As a result, when the control power supply circuit 15 operates, control power is supplied to the microcontroller unit 16, and in step S503, the microcontroller unit 16 starts up.

[0058] The operated microcontroller unit 16 detects the voltage level of the DC low voltage DC3 of the low-voltage battery 12, and in step S504, detects whether the voltage level of the DC low voltage DC3 is equal to or lower than the specified lower limit voltage value V LOW In other words, this determination is made whether DC3>V LOWIt is determined whether or not the voltage level of the DC low voltage DC3 of the low-voltage battery 12 is the power source for the external electronic control unit, so it is also possible to collect and detect the voltage level from the CAN information. Also, if a dedicated sensor is provided to detect the voltage level of the DC low voltage DC3 of the low-voltage battery 12, the information may be obtained from the sensor.

[0059] As a result of the above judgment, the voltage level of the DC low voltage DC3 is the lower limit voltage value V LOW If the lower limit voltage value V is less than the lower limit voltage value V, the microcontroller unit 16 determines that the DC low voltage DC3 of the low voltage battery 12 is in an abnormal output state and that the AC / DC conversion and control power supply circuit 22 is in a normal operating state. Then, in step S505, the AC normal charging of the high voltage battery 11 is started. LOW is an example of the first predetermined voltage in the claims.

[0060] A specific example of the power conversion voltage generation unit is a functional configuration including a DC / DC converter 18 and an AC / DC converter 19, similar to the above-described on-board chargers 10, 10A, and 10B. Here, the microcontroller unit 16 controls the drive circuit 17, and the AC / DC converter 19 driven by the drive circuit 17 converts the AC voltage from the external AC power source 1 into a DC voltage DC1. The microcontroller unit 16 also controls the drive circuit 17, and the DC / DC converter 18 driven by the drive circuit 17 converts the DC voltage DC1 into a DC high voltage DC2. The microcontroller unit 16 then charges the high-voltage battery 11 using the DC high voltage DC2 for applying a high voltage.

[0061] After charging the high-voltage battery 11, the microcontroller unit 16 records the abnormality of the low-voltage battery 12 and the normal operating state of the AC / DC conversion and control power supply circuit 22. The timing for recording the abnormality of the low-voltage battery 12 may be the timing when the determination result of step S504 is NO. Also, the DC / DC converter 20 is operated as necessary, and the low-voltage battery 12 is charged by the DC / DC converter 20 with the DC low voltage DC3. Here, if the abnormal state of the voltage level of the low-voltage battery 12 is recorded and displayed to the user, the user can be notified that an abnormality has occurred in the low-voltage battery 12.

[0062] In contrast, as a result of the determination in step S504, the voltage level of the DC low voltage DC3 is lower than the lower limit voltage value V LOW If the voltage level is higher than the threshold voltage Vcc, the microcontroller unit 16 continues to perform the determination in step S506 since the voltage level is normal. Step S506 is a step for determining whether the backup DC voltage DC4 is normally output. In this embodiment, the AC / DC conversion and control power supply circuit 22 does not have a voltage sensor for detecting its own output voltage, that is, the voltage applied to the anode terminal of the diode D1, in order to reduce circuit costs. Therefore, the control power supply circuit input voltage DC5, which is the input voltage of the control power supply circuit 15, is used to determine whether the backup DC voltage DC4, which is the output voltage of the AC / DC conversion and control power supply circuit 22, is normal. The microcontroller unit 16 determines whether the voltage value of DC5 is equal to DC4a, which is a voltage representing the normal value of DC4 previously recorded in the microcontroller unit 16. DC4a is an example of a second predetermined voltage in the claims.

[0063] If the result of the determination in step S506 is that DC5=DC4a, it is determined that the AC / DC conversion and control power supply circuit 22 is in an abnormal output state even if the control power supply circuit 15 is in a normal operating state while the on-board charger 10C is activated with the DC low voltage DC3. Therefore, in step S507, the microcontroller unit 16 sets DC4EN=OFF and inputs a signal to the AC / DC conversion and control power supply circuit 22 to stop operation. Note that the signal to stop the AC / DC conversion and control power supply circuit 22 is an example of a stop signal in the claims. Note that, taking into consideration the variation of the components constituting the AC / DC conversion and control power supply circuit 22 and the fluctuation of the input voltage, a margin may be provided for DC4a, which is a voltage representing the normal value of DC4.

[0064] Next, step S508 shows the stopping of operation of the AC / DC conversion and control power supply circuit 22. If the backup DC voltage DC4 exceeds the voltage value of the low-voltage battery DC3 at the time when AC / DC4 is turned off, the power supply to the microcontroller unit 16 is switched to the low-voltage battery 12. Also, if the backup DC voltage DC4 does not exceed the low-voltage battery DC3, it is considered that power supply to the microcontroller unit 16 would have been performed from the low-voltage battery 12 before AC / DC4 was turned off, but for safety reasons, the AC / DC conversion and control power supply circuit 22 is stopped.

[0065] After stopping the AC / DC conversion and control power supply circuit 22, in step S505, the microcontroller unit 16 starts normal AC charging of the high-voltage battery 11. Also, if necessary, the DC / DC converter 20 is operated to charge the low-voltage battery 12 with the DC low voltage DC3 by the DC / DC converter 20.

[0066] After charging the high-voltage battery 11, the microcontroller unit 16 records the normal operating state of the low-voltage battery 12 and the output abnormal state of the AC / DC conversion and control power supply circuit 22. The output abnormal state of the AC / DC conversion and control power supply circuit 22 may be recorded when it is detected in step S506 that DC5 is not equal to DC4a, when DC4EN is set to OFF in step S507, or when AC / DC4 is turned OFF in step S508.

[0067] Furthermore, if the result of the judgment in step S506 is DC5=DC4a, the microcontroller unit 16 proceeds to step S509. In step S509, the microcontroller unit 16 judges whether the mode is normal or periodic diagnosis. If the result of the judgment is periodic diagnosis mode, in step S505, the microcontroller unit 16 controls the power conversion voltage generation unit to start AC normal charging of the high-voltage battery 11 with the DC high voltage DC2 generated from the AC voltage while receiving power from the AC / DC conversion and control power supply circuit 22.

[0068] After charging the high-voltage battery 11, the microcontroller unit 16 records, as diagnostic results, the normal operating voltage value of the low-voltage battery 12 and the normal operating state of the AC / DC conversion and control power supply circuit 22. Also, as necessary, the DC / DC converter 20 is operated to charge the low-voltage battery 12 with the DC low voltage DC3 by the DC / DC converter 20.

[0069] Furthermore, if the result of the judgment in step S509 is that the mode is normal, then in step S510 the microcontroller unit 16 transitions to a state where AC / DC4=OFF, indicating that the operation of the AC / DC conversion and control power supply circuit 22 is off. Then, in step S511, it indicates that the operation of the AC / DC conversion and control power supply circuit 22 has stopped. At the point in time when AC / DC4 is OFF, the power supply to the microcontroller unit 16 is switched to the low-voltage battery 12. After that, in step S505, the microcontroller unit 16 starts normal AC charging of the high-voltage battery 11.

[0070] After charging the high-voltage battery 11, the microcontroller unit 16 records the normal operating state of the low-voltage battery 12 and the normal operating voltage value of the AC / DC conversion and control power supply circuit 22. Also, if necessary, the DC / DC converter 20 is operated to charge the low-voltage battery 12 with the DC low voltage DC3 by the DC / DC converter 20.

[0071] In the case of the in-vehicle charger 10C, if the voltage value of the backup DC voltage DC4 is set sufficiently higher than the voltage value of the DC low voltage DC3, the AC / DC conversion and control power supply circuit 22 can be used even if there is no abnormality in the low-voltage battery 12. In particular, it is possible to periodically check whether the AC / DC conversion and control power supply circuit 22 can operate under an actual load.

[0072] In the case of the on-board charger 10C of the third embodiment, even if the low-voltage battery 12 is in an abnormal state such as being dead, it is possible to charge the high-voltage battery 11, and then charge the low-voltage battery 12. This allows redundancy with the conductive wire of the low-voltage battery 12. The on-board charger 10C is capable of periodic diagnosis of the AC / DC conversion and control power supply circuit 22 under an actual load, and can also notify of deterioration of the low-voltage battery 12, and therefore has a feature superior to the on-board charger 10B in terms of convenience and multi-function for use in electric vehicles. [Explanation of symbols]

[0073] 1 AC power supply 2 charger 3 External charging cable connection 10, 10A, 10B, 10C car charger 11 High Voltage Battery 12 Low Voltage Battery 13 Electronic Control Unit (ECU1) 14 Electronic control unit (ECU2) 15 Control power supply circuit 16 Microcontroller Unit (MCU) 17 Driver circuit 18 DC / DC converter (DC1 / DC2) 19 AC / DC converter (AC / DC1) 20 DC / DC converter (DC2 / DC3) 22 AC / DC conversion and control power supply circuit (AC / DC4) 100, 100A, 100B, 100C EV

Claims

1. An on-board charger for charging a high-voltage battery mounted on a vehicle, a first power conversion unit that converts power from an external power supply into a first power for charging the high-voltage battery; a second power conversion unit that converts the power of the external power supply into a second power for controlling the first power conversion unit; a selection unit that supplies either the second power or power output from a low-voltage battery to a control unit of the first power conversion unit; The control unit includes: Determine whether the device is in normal mode or periodic diagnostic mode; In the normal mode, the operation of the second power conversion unit is stopped and the power output from the low-voltage battery is received. If the periodic diagnosis mode is selected, the vehicle-mounted charger operates the second power conversion unit to receive the second power.

2. The voltage of the second power is Lower than the voltage output from the low-voltage battery The vehicle-mounted charger according to claim 1 .

3. The voltage of the second power is Higher than the voltage output from the low-voltage battery The vehicle-mounted charger according to claim 1 .

4. The control unit is inputting a stop signal to the second power conversion unit; The second power conversion unit is Continue running until the stop signal is input The vehicle-mounted charger according to claim 3 .

5. The control unit is The voltage of the power output from the low-voltage battery to the control unit is If it is equal to or lower than the first predetermined voltage, The first power conversion unit is operated using the second power. The vehicle-mounted charger according to claim 4.

6. The control unit is The voltage of the second power is If it is not the second predetermined voltage, inputting the stop signal to the second power conversion unit; Using the power output from the low-voltage battery to the control unit, Operate the first power conversion unit The vehicle-mounted charger according to claim 5 .

7. The control unit is If it is in normal mode, inputting the stop signal to the second power conversion unit; Using the power input from the low voltage battery to the control unit, Operate the first power conversion unit The vehicle-mounted charger according to claim 6.

8. The vehicle-mounted charger according to claim 3 is provided, Furthermore, a signal for starting the second power conversion unit is input from outside the vehicle-mounted charger. Equipped with a start signal input section In-vehicle charging system.

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