Abstract:
A power-supply apparatus includes: a battery; a charger that charges the battery; a charging relay provided on a power line to connect/disconnect the battery and the charger to/from each other through an on-off operation; a first voltage sensor attached to a portion of the power line between the charger and the charging relay; a second voltage sensor attached to a portion of the power line between the battery and the charging relay; and an ECU that permits detection of a deviation abnormality in which a deviation between a charger-side voltage and a battery-side voltage is equal to or greater than a threshold when it is verified that the battery is being charged by the charger while the charging relay is on, and prohibits the detection when it is not verified that the battery is being charged by the charger while the charging relay is on.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Japanese Patent Application No. 2016-057195 filed on Mar. 22, 2016, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND 
     1. Technical Field 
       [0002]    The disclosure relates generally to a power-supply apparatus, and relates more specifically to a power-supply apparatus including a charger configured to charge a battery with externally-supplied electric power. 
       2. Description of Related Art 
       [0003]    An example of this kind of power-supply apparatus is a power-supply apparatus in which a relay is attached to a power line that connects a battery and a charger to each other (see, for example, Japanese Unexamined Patent Application Publication No. 2011-160604 (JP 2011-160604 A)). In the power-supply apparatus, the relay is turned on when the charger charges the battery with electric power supplied from an external power supply. In this case, when a deviation between a voltage from a voltage sensor that is disposed closer to the charger than the relay is (hereinafter, referred to as “charger-side voltage sensor”) and a voltage from a voltage sensor that is disposed closer to the battery than the relay is (hereinafter, referred to as “battery-side voltage sensor”), is equal to or greater than a threshold, it is determined that a malfunction has occurred in the charger-side voltage sensor. 
       SUMMARY 
       [0004]    However, in the power-supply apparatus described above, when the power line breaks at a position that is closer to the battery than the charger-side voltage sensor is, the voltage from the charger-side voltage sensor increases and the deviation between the voltage from the charger-side voltage sensor and the voltage from the battery-side voltage sensor becomes equal to or greater than the threshold. In this case, it is determined that a voltage sensor malfunction has occurred, although the charger-side voltage sensor is actually not malfunctioning. 
         [0005]    The disclosure provides a power-supply apparatus configured to more appropriately make a determination regarding abnormalities, such as breaking of a power line and a sensor malfunction. 
         [0006]    A power-supply apparatus according to an aspect of the disclosure includes: a battery; a charger configured to charge the battery with electric power supplied from an external power supply; a charging relay provided on a power line, the charging relay configured to connect the battery and the charger to each other or disconnect the battery and the charger from each other through an on-off operation; a first voltage sensor attached to a portion of the power line that is closer to the charger than the charging relay is; a second voltage sensor attached to a portion of the power line that is closer to the battery than the charging relay is; and an electronic control unit configured to verify whether or not the battery is being charged by the charger while the charging relay is on. The electronic control unit is configured to i) permit detection of a deviation abnormality when it is verified that the battery is being charged by the charger while the charging relay is on, the deviation abnormality being an abnormality in which a deviation between a charger-side voltage detected by the first voltage sensor and a battery-side voltage detected by the second voltage sensor is equal to or greater than a threshold, and ii) prohibit detection of the deviation abnormality when it is not verified that the battery is being charged by the charger while the charging relay is on. 
         [0007]    In the power-supply apparatus according to the above aspect, the electronic control unit verifies whether or not the battery is being charged by the charger while the charging relay is on. The electronic control unit permits detection of a deviation abnormality when it is verified that the battery is being charged by the charger while the charging relay is on. The deviation abnormality is an abnormality in which the deviation between the charger-side voltage detected by the first voltage sensor, which is attached to a portion of the power line that is closer to the charger than the charging relay is, and the battery-side voltage detected by the second voltage sensor, which is attached to a portion of the power line that is closer to the battery than the charging relay is, is equal to or greater than the threshold. When it is verified that the battery is being charged by the charger while the charging relay is on, detection of a deviation abnormality is permitted because it is considered that breaking of the power line has not occurred. Thus, it is possible to detect, for example, a sensor malfunction based on detection of a deviation abnormality. On the other hand, when it is not verified that the battery is being charged by the charger while the charging relay is on, detection of a deviation abnormality is prohibited. When it is not verified that the battery is being charged by the charger while the charging relay is on, there is a high possibility that breaking of the power line has occurred. Therefore, it is possible to reduce false detection, such as detection of a sensor malfunction based on detection of a deviation abnormality. As a result, it is possible to more appropriately make a determination regarding abnormalities, such as breaking of a power line and a sensor malfunction. Whether or not the battery is being charged by the charger can be verified based on a determination as to whether or not a value of a current passing through the battery is zero or based on a determination as to whether or not a value of electric power supplied from the external power supply to the charger is zero. Whether or not the value of the electric power supplied from the external power supply to the charger is zero can be determined based on whether or not a value of a current input into the charger from the external power supply is zero. 
         [0008]    In the power-supply apparatus according to the above aspect, the electronic control unit may be configured to i) determine whether or not the charger-side voltage is lower than the battery-side voltage, and ii) permit detection of the deviation abnormality when the charger-side voltage is lower than the battery-side voltage, regardless of whether or not it is verified that the battery is being charged by the charger. A voltage of the battery is monitored through double monitoring including monitoring of the charger-side voltage from the first voltage sensor and monitoring of the battery-side voltage from the second voltage sensor. When at least one of an abnormal state where the charger-side voltage from the first voltage sensor is excessively high and an abnormal state where the battery-side voltage from the second voltage sensor is excessively low has occurred, the charger-side voltage becomes higher than the battery-side voltage. In this case, protection of the battery is executed depending on whether or not the charger-side voltage exceeds an overcharging threshold. On the other hand, when at least one of an abnormal state where the charger-side voltage from the first voltage sensor is excessively low and an abnormal state where the battery-side voltage from the second voltage sensor is excessively high has occurred, the charger-side voltage becomes lower than the battery-side voltage. In this case, it is not possible to execute protection of the battery depending on whether or not the charger-side voltage exceeds the overcharging threshold. In this case, the deviation between the charger-side voltage and the battery-side voltage increases due to charging of the battery. Thus, a large increase in the deviation can be detected as a deviation abnormality, before the battery is overcharged. 
         [0009]    In the power-supply apparatus according to the above aspect, the electronic control unit may be configured to verify whether or not the battery is being charged by the charger, based on whether or not a value of a current passing through the battery is zero or based on whether or not a value of electric power supplied from the external power supply to the charger is zero. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Features, advantages, and technical and industrial significance of exemplary embodiments will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
           [0011]      FIG. 1  is a schematic diagram illustrating a configuration of a power-supply apparatus according to an embodiment of the disclosure; 
           [0012]      FIG. 2  is a flowchart illustrating an example of a deviation abnormality detection permission-prohibition routine executed by a charging electronic control unit (ECU); 
           [0013]      FIG. 3  is a graph illustrating an example of each of a temporal change in a deviation between a charging voltage and a battery voltage, a temporal change in a battery current, and a temporal change in a charger input electric power when breaking of a power line has occurred; 
           [0014]      FIG. 4  is a graph illustrating an example of each of a temporal change in the charging voltage and a temporal change in the battery voltage when the charging voltage is lower than the battery voltage; and 
           [0015]      FIG. 5  is a flowchart illustrating an example of a deviation abnormality detection permission-prohibition routine according to a modified example. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0016]    Hereinafter, an embodiment of the disclosure will be described with reference to the accompanying drawings. 
         [0017]      FIG. 1  is a schematic diagram illustrating a configuration of a power-supply apparatus  20  according to an embodiment of the disclosure. The power-supply apparatus  20  according to the present embodiment is mounted in a movable body, such as an electric vehicle or a hybrid vehicle. The power-supply apparatus  20  functions as a power supply for, for example, a motor for traveling. In the present embodiment, for the sake of the convenience, description will be provided on the assumption that the power-supply apparatus  20  is provided as a power supply of a hybrid vehicle. As illustrated in  FIG. 1 , the power-supply apparatus  20  according to the present embodiment includes a charger  22 , a charging relay  24 , a battery  30 , a charging electronic control unit  26  (hereinafter, referred to as “charging ECU  26 ”), a battery electronic control unit  36  (hereinafter, referred to as “battery ECU  36 ”), and a hybrid vehicle electronic control unit  40  (hereinafter, referred to as “HVECU  40 ”). 
         [0018]    The charger  22  is connected to the battery  30  through a power line  23 . The charger  22  is configured to charge the battery  30  with electric power supplied from an external power supply while a connector  21  is connected to a connector  11  of the external power supply. The charger  22  includes an AC-DC converter and a DC-DC converter, both of which are not illustrated. The AC-DC converter converts alternating-current power supplied from the external power supply via the connector  21 , into direct-current power. The DC-DC converter converts the voltage of the direct-current power from the AC-DC converter, and then supplies, toward the battery  30 , the direct-current power that has undergone the voltage conversion. While the connector  21  is connected to the connector  11  of the external power supply, the charger  22  supplies the electric power from the external power supply to the battery  30  under control of the charging ECU  26  executed on the AC-DC converter and the DC-DC converter. 
         [0019]    Although not illustrated in detail, the charging ECU  26  has a configuration as a microprocessor mainly including a central processing unit (CPU), and further including, for example, a read-only memory (ROM) configured to store processing programs, a random-access memory (RAM) configured to temporarily store data, an input port, an output port, and a communication port, in addition to the CPU. Various signals are input into the charging ECU  26  through the input port. The various signals include signals from various sensors attached to the charger  22 , and a connection signal from a connection switch  21 a attached to the connector  21  and configured to determine whether or not the connector  21  has been connected to the connector  11  of the external power supply. Further, an input current Iin from a current sensor  27  and a charging voltage Vchg from a voltage sensor  29  are input into the charging ECU  26 . The current sensor  27  is configured to detect a current to be input into the charger  22  from the external power supply. The voltage sensor  29  is configured to detect a voltage across terminals of a capacitor  28 , as a charging voltage Vchg from the charger  22 . For example, control signals for the AC-DC converter and the DC-DC converter of the charger  22  are output from the charging ECU  26  through the output port. The charging ECU  26  communicates with the HVECU  40 , so that information obtained by the charging ECU  26  is transmitted to the HVECU  40  as necessary. 
         [0020]    The battery  30  has a configuration as, for example, a lithium-ion secondary battery. The battery  30  is connected to a load, such as a motor for traveling (not illustrated), via a system main relay  42 . Further, the battery  30  is connected, via the charging relay  24 , to the charger  22  through the power line  23 . The smoothing capacitor  28  is attached to the power line  23 , at a position between the charger  22  and the charging relay  24 . The battery  30  is controlled by the battery ECU  36 . 
         [0021]    Although not illustrated in detail, the battery ECU  36  has a configuration as a microprocessor mainly including a CPU, and further including, for example, a ROM configured to store processing programs, a RAM configured to temporarily store data, an input port, an output port, and a communication port, in addition to the CPU. Various signals are input into the battery ECU  36  through the input port. The various signals include a battery current Ib from a current sensor  31  attached to a power line connected to an output terminal of the battery  30 , and a battery voltage Vb from a voltage sensor  32  disposed between the terminals of the battery  30 . For example, a driving signal for the charging relay  24  is output from the battery ECU  36  through the output port. The battery ECU  36  communicates with the HVECU  40 , so that information obtained by the battery ECU  36  is transmitted to the HVECU  40  as necessary. 
         [0022]    Although not illustrated in detail, the HVECU  40  has a configuration as a microprocessor mainly including a CPU, and further including, for example, a ROM configured to store processing programs, a RAM configured to temporarily store data, an input port, an output port, and a communication port, in addition to the CPU. The HVECU  40  turns on the system main relay  42  upon system startup, controls the entire system of the hybrid vehicle, and controls driving of a load, such as a motor for traveling (not illustrated). As described above, the HVECU  40  communicates with the charging 
         [0023]    ECU  26  and the battery ECU  36 , so that the HVECU  40  receives necessary information from the charging ECU  26  and the battery ECU  36 . 
         [0024]    In the present embodiment, the connector  21 , the charger  22 , the charging relay  24 , the charging ECU  26 , the battery  30 , the battery ECU  36 , and the HVECU  40  are function as the power-supply apparatus  20 . 
         [0025]    The HVECU  40  detects a deviation abnormality when a deviation ΔV(ΔV=|Vchg−Vb|) between the charging voltage Vchg and the battery voltage Vb, which is the voltage across terminals of the battery  30 , becomes equal to or greater than a threshold while the charger  22  is charging the battery  30 . On the other hand, the HVECU  40  determines whether or not breaking of the power line  23  has occurred. When breaking of the power line  23  has occurred, the HVECU  40  outputs a signal indicating the occurrence of breaking of the power line  23 . When breaking of the power line  23  has occurred, a deviation abnormality is also detected. In view of this, the HVECU  40  according to the present embodiment executes a deviation abnormality detection permission-prohibition routine in  FIG. 2  in order to distinguish breaking of the power line  23  and a deviation abnormality from each other. The deviation abnormality detection permission-prohibition routine is repeatedly executed at prescribed time intervals (e.g., every several milliseconds). 
         [0026]    Upon start of execution of the deviation abnormality detection permission-prohibition routine, the HVECU  40  first determines whether or not the charger  22  and the battery  30  are connected to each other by the charging relay  24  (step S 100 ). The HVECU  40  can make this determination based on the information indicating whether the charging relay  24  is on or off, which is received from the charging ECU  26 . When determining that the charger  22  and the battery  30  are not connected to each other by the charging relay  24 , the HVECU  40  determines that detection of a deviation abnormality is not necessary because charging of the battery  30  is not being performed, and does not permit detection of a deviation abnormality (step S 140 ). Then, the HVECU  40  ends the present routine. 
         [0027]    When determining in step S 100  that the charger  22  and the battery  30  are connected to each other by the charging relay  24 , the HVECU  40  determines whether or not the charging voltage Vchg is lower than the battery voltage Vb (step S 110 ). When determining that the charging voltage Vchg is equal to or higher than the battery voltage Vb, the HVECU  40  verifies whether or not the battery  30  is being charged by the charger  22  (step S 120 ).  FIG. 3  is a graph illustrating an example of each of a temporal change in the deviation AV between the charging voltage Vchg and the battery voltage Vb, a temporal change in the battery current Ib, and a temporal change in electric power Wchg that is input into the charger  22  (hereinafter, referred to as “charger input electric power Wchg”), when breaking of the power line  23  has occurred. As illustrated in  FIG. 3 , when breaking of the power line  23  occurs at time T 1 , the deviation AV increases with an increase in the charging voltage Vchg. The absolute value of the battery current Ib starts decreasing at time T 1  and finally becomes equal to zero. The charger input electric power Wchg becomes equal to zero because the power supply to the charger  22  is stopped upon detection of breaking of the power line  23 . In the present embodiment, the HVECU  40  verifies whether or not the battery  30  is being charged by the charger  22 , by verifying whether or not the battery current Ib is zero. More specifically, it is verified that the battery  30  is being charged by the charger  22  when the battery current Ib is not zero, whereas it is not verified that the battery  30  is being charged by the charger  22  when the battery current Ib is zero. The battery current Ib is a current passing through the battery  30 , and is detected by the current sensor  31 . When it is verified that the battery  30  is being charged by the charger  22 , the HVECU  40  determines that breaking of the power line  23  has not occurred, and permits detection of a deviation abnormality (step S 130 ). Then, the HVECU  40  ends the present routine. Thus, it is possible to detect, for example, a malfunction of the voltage sensor  29  based on the detection of a deviation abnormality. On the other hand, when it is not verified that the battery  30  is being charged by the charger  22 , the HVECU  40  determines that there is a possibility that breaking of the power line  23  has occurred, and does not permit detection of a deviation abnormality (step S 140 ). Then, the HVECU  40  ends the present routine. Thus, it is possible to reduce false detection of, for example, a malfunction of the voltage sensor  29  based on detection of a deviation abnormality. 
         [0028]    When the HVECU  40  determines in step S 110  that the charging voltage Vchg is lower than the battery voltage Vb, detection of a deviation abnormality is permitted regardless of whether or not the battery  30  is being charged by the charger  22  (step S 130 ). Then, the HVECU  40  ends the present routine. The voltage of the battery  30  is monitored through double monitoring including monitoring of the battery voltage Vb from the voltage sensor  32  and monitoring of the charging voltage Vchg from the voltage sensor  29 . When at least one of an abnormal state where the charging voltage Vchg from the voltage sensor  29  is excessively high and an abnormal state where the battery voltage Vb from the voltage sensor  32  is excessively low has occurred, the charging voltage Vchg becomes equal to or higher than the battery voltage Vb. In this case, protection of the battery  30  is executed depending on whether or not the charging voltage Vchg exceeds an overcharging threshold. On the other hand, when at least one of an abnormal state where the charging voltage Vchg from the voltage sensor  29  is excessively low and an abnormal state where the battery voltage Vb from the voltage sensor  32  is excessively high has occurred, the charging voltage Vchg becomes lower than the battery voltage Vb. In this case, it is not possible to execute protection of the battery  30  depending on whether or not the charging voltage Vchg exceeds the overcharging threshold. In view of this, in order to detect such an abnormality, detection of a deviation abnormality is permitted. The deviation between the charging voltage Vchg and the battery voltage Vb increases with an increase in the charging time, as illustrated in  FIG. 4 . Thus, a large increase in the deviation can be detected as a deviation abnormality, before the battery  30  is overcharged. 
         [0029]    In the power-supply apparatus  20  according to the embodiment described so far, when it is verified that the battery  30  is being charged by the charger  22  while the charging relay  24  is on, detection of a deviation abnormality is permitted. A deviation abnormality means an abnormal state where the deviation AV between the charging voltage Vchg and the battery voltage Vb is equal to or greater than the threshold. In this case, it is determined that breaking of the power line  23  has not occurred. Thus, even when a deviation abnormality is detected, the deviation abnormality can be distinguished from a deviation abnormality due to breaking of the power line  23 . Thus, it is possible to detect, for example, a malfunction of the voltage sensor  29  based on detection of a deviation abnormality. On the other hand, when it is not verified that the battery  30  is being charged by the charger  22  while the charging relay  24  is on, detection of a deviation abnormality is not permitted. This is because there is a possibility that breaking of the power line  23  has occurred. In this way, it is possible to distinguish breaking of the power line  23  and an abnormality of deviation between the charging voltage Vchg and the battery voltage Vb. As a result, it is possible to more appropriately make determination regarding abnormalities, such as breaking of the power line  23  and a sensor malfunction. Moreover, when the charging voltage Vchg is lower than the battery voltage Vb, detection of a deviation abnormality is permitted regardless of whether or not the battery  30  is being charged by the charger  22 . Thus, it is possible to detect a deviation abnormality due to occurrence of at least one of an abnormal state where the charging voltage Vchg from the voltage sensor  29  is excessively low and an abnormal state where the battery voltage Vb from the voltage sensor  32  is excessively high. 
         [0030]    In the power-supply apparatus  20  according to the present embodiment, when the charging voltage Vchg is lower than the battery voltage Vb, detection of a deviation abnormality is permitted regardless of whether or not it is verified that the battery  30  is being charged by the charger  22 . However, as illustrated in a deviation abnormality detection permission-prohibition routine according to a modified example in  FIG. 5 , detection of a deviation abnormality may be permitted or prohibited by verifying whether or not the battery  30  is being charged by the charger  22 , without determining whether or not the charging voltage Vchg is lower than the battery voltage Vb. In this case as well, even when a deviation abnormality is detected, the deviation abnormality can be distinguished from a deviation abnormality due to breaking of the power line  23 . 
         [0031]    In the power-supply apparatus  20  according to the foregoing embodiment, the HVECU  40  executes the deviation abnormality detection permission-prohibition routine in  FIG. 2 . Alternatively, the charging ECU  26  may execute the deviation abnormality detection permission-prohibition routine, or the battery ECU  36  may execute the deviation abnormality detection permission-prohibition routine. 
         [0032]    The power-supply apparatus  20  according to the foregoing embodiment include three electronic control units, that is, the charging ECU  26 , the battery ECU  36 , and the HVECU  40 . Alternatively, the power-supply apparatus  20  may include one electronic control unit, two electronic control units, or four or more electronic control units. 
         [0033]    The deviation abnormality detection permission-prohibition routine in  FIG. 2  may be executed by any one of the electronic control units. 
         [0034]    In the foregoing embodiment, the power-supply apparatus  20  is provided as a power supply for a hybrid vehicle. Alternatively, the power-supply apparatus  20  may be provided as a power supply for an electric vehicle as described above, or the power-supply apparatus  20  may be incorporated in equipment other than a movable body, such as a hybrid vehicle or an electric vehicle. 
         [0035]    In the foregoing embodiment, the battery  30  is an example of “battery”, the charger  22  is an example of “charger”, the charging relay  24  is an example of “charging relay”, and the HVECU  40  configured to execute the deviation abnormality detection permission-prohibition routine in  FIG. 2  is an example of “electronic control unit”. 
         [0036]    While one embodiment of the disclosure has been described above, the disclosure is not limited to the foregoing embodiment and may be implemented in various other embodiments within the technical scope of the disclosure. 
         [0037]    The disclosure may be used in, for example, the manufacturing industry for power-supply apparatuses.