JP2016161357A - Power supply monitoring device and power supply monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration and suppress an increase in costs while making it possible to detect a power supply voltage and the degradation of insulation resistance.SOLUTION: This power supply monitoring device comprises a first and a second capacitor, a capacitor switching unit, and a power supply monitoring unit. The first capacitor is used to detect the voltage of the power supply. The second capacitor is connected to the first capacitor via a selector switch and used to detect the degradation of the insulation resistance of the power supply. The capacitor switching unit switches, by controlling the selector switch, between a first charge path including the first capacitor and a second charge path including the second capacitor. The power supply monitoring unit detects the voltage of the power supply at the time of the first charge path and detects the degradation of the insulation resistance of the power supply at the time of the second charge path on the basis of the voltage of the capacitor charged via the first charge path or the second charge path, and thereby monitors the state of the power supply.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power supply monitoring apparatus and a power supply monitoring method.

  2. Description of the Related Art Conventionally, for example, a vehicle such as a hybrid vehicle or an electric vehicle includes a power source that supplies power to a motor that is a power source, and a device that monitors the state of the power source is known.

  Since the power supply described above is configured to be insulated from the vehicle body, the power supply monitoring device has a function of monitoring the insulation state of the power supply, in other words, a function of detecting deterioration of the insulation resistance of the power supply. (For example, refer to Patent Document 1). In the above prior art, the deterioration of the insulation resistance of the power source is detected using the flying capacitor method. Specifically, in the prior art, the capacitor is charged by passing current from the power supply through the insulation resistance, and the deterioration of the insulation resistance of the power supply is detected based on the charged voltage of the capacitor.

  Furthermore, the above-described power supply monitoring device includes a circuit for detecting the power supply voltage separately from the circuit for detecting deterioration of the insulation resistance, and also monitors the power supply voltage.

JP 2014-20914 A

  However, when the circuit for detecting the power supply voltage and the circuit for detecting deterioration of the insulation resistance are separate as in the prior art described above, the configuration of the power supply monitoring device may be complicated and the cost may increase. It was.

  The present invention has been made in view of the above, and a power supply monitoring apparatus and a power supply monitoring method capable of detecting a power supply voltage and detecting deterioration of insulation resistance while simplifying the configuration and suppressing an increase in cost. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, the present invention is a power supply monitoring device, which includes a first capacitor, a second capacitor, a capacitor switching unit, and a power supply monitoring unit. The first capacitor is connected to an insulated power source and used for voltage detection of the power source. The second capacitor is connected to the power supply and is connected to the first capacitor via a changeover switch, and is used for detecting deterioration of the insulation resistance of the power supply. The capacitor switching unit controls the changeover switch to switch between a first charging path including the first capacitor without including the second capacitor and a second charging path including at least the second capacitor. A power monitoring unit that detects a voltage of the power source based on a voltage of the capacitor charged in the first charging path or the second charging path switched by the capacitor switching unit; During the second charging path, the deterioration of the insulation resistance of the power source is detected and the state of the power source is monitored.

  According to the present invention, it is possible to detect the power supply voltage and detect the deterioration of the insulation resistance while simplifying the configuration of the power supply monitoring device and suppressing an increase in cost.

FIG. 1 is a block diagram illustrating a configuration example of a charge / discharge system including a power monitoring device according to an embodiment. FIG. 2 is a block diagram illustrating a configuration example of the power supply monitoring apparatus. FIG. 3 is a diagram illustrating a configuration example of the voltage detection circuit unit. FIG. 4 is a diagram illustrating a charging path for charging the first capacitor with the voltage of the first stack. FIG. 5 is a diagram illustrating a discharge path for discharging the charged first capacitor. FIG. 6 is a diagram illustrating a charging path for charging the first capacitor with the voltage of the second stack. FIG. 7 is a diagram illustrating a charging path when detecting deterioration of the insulation resistance on the positive electrode side of the assembled battery. FIG. 8 is a diagram illustrating a discharge path for discharging the charged capacitor. FIG. 9 is a diagram illustrating a charging path when detecting deterioration of the insulation resistance on the negative electrode side of the assembled battery. FIG. 10 is a flowchart illustrating a part of a processing procedure of processing executed by the power supply monitoring system.

  Hereinafter, embodiments of a power supply monitoring device and a degradation detection method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

<1. Configuration of charge / discharge system>
FIG. 1 is a block diagram illustrating a configuration example of a charge / discharge system including a power monitoring device according to an embodiment. The charge / discharge system 1 is mounted on a vehicle such as a hybrid vehicle (HEV), an electric vehicle (EV), and a fuel cell vehicle (FCV) (not shown). The charge / discharge system 1 is a system that performs charge / discharge of a power source that supplies electric power to a motor that is a power source of a vehicle.

  Specifically, the charge / discharge system 1 includes an assembled battery 10, a power supply monitoring system 20, a vehicle control device 30, a motor 40, a voltage converter 50, and a fail-safe relay 60. The power supply monitoring system 20 includes a plurality of satellite boards 22 having a monitor IC (Integrated Circuit) 21 and the like, and a power supply monitoring device 23.

  The assembled battery 10 is a power source (battery) insulated from a vehicle body (not shown), and includes a plurality of blocks 11. One block 11 includes a plurality of, for example, two battery stacks 12 connected in series. Further, one battery stack 12 includes a plurality of battery cells 13 connected in series, for example.

  The numbers of blocks 11, battery stacks 12, and battery cells 13 are not limited to those described above or illustrated. Moreover, as the above-described assembled battery 10, for example, a lithium ion secondary battery, a nickel hydride secondary battery, or the like can be used, but the present invention is not limited to this.

  Each of the plurality of battery cells 13 is electrically connected to a monitor IC 21 provided on the satellite substrate 22. Then, the voltage of each battery cell 13 is detected by the monitor IC 21. The monitor IC 21 includes a plurality of first monitor ICs 21a and second monitor ICs 21b, and each of the first and second monitor ICs 21a and 21b detects the voltage of the battery cells 13 for one battery stack 12.

  The power monitoring device 23 has a function of monitoring individual voltages of the plurality of battery cells 13 and monitoring the voltage of each battery stack 12. That is, the power monitoring device 23 monitors the state of charge of the assembled battery 10.

  Specifically, the power supply monitoring device 23 transmits a voltage detection request to the monitor IC 21 to detect each individual voltage of the plurality of battery cells 13 and receives the detection result via the communication line L1. The voltage of the battery cell 13 is monitored. Further, the power supply monitoring device 23 directly measures the stack voltage by charging the voltage of the battery stack 12 (hereinafter sometimes referred to as “stack voltage”) to a capacitor, which will be described later, via the conductive wire L2, and sets the assembled voltage. The state of charge of the battery 10 is monitored.

  The power supply monitoring device 23 preferably has a function of determining whether or not the monitor IC 21 is operating normally. Specifically, for example, the power supply monitoring device 23 compares the stack voltage obtained by adding the individual voltages of the battery cells 13 received from the monitor IC 21 with the stack voltage directly detected, and the difference between the two is acceptable. When it is larger than the value, it is determined that the monitor IC 21 is abnormal. Then, when it is determined that the monitor IC 21 is abnormal, the power supply monitoring device 23 may disconnect the fail-safe relay 60 so that the battery cell 13 is not charged / discharged.

  The power supply monitoring device 23 detects deterioration of insulation resistance (described later) of the power supply monitoring system 20, which will be described later. Here, the deterioration of the insulation resistance means that, for example, the resistance value of the insulation resistance is lowered and the battery pack 10 is leaked.

  The vehicle control device 30 performs vehicle control by charging / discharging the assembled battery 10 according to the state of charge of the assembled battery 10. Specifically, the vehicle control device 30 uses the voltage converter 50 to convert the voltage charged in the assembled battery 10 from direct current to alternating current voltage, and supplies the converted voltage to the motor 40 to drive the motor 40. Let Thereby, the assembled battery 10 is discharged.

  Further, the vehicle control device 30 converts the voltage generated by the regenerative braking of the motor 40 from an AC voltage to a DC voltage by the voltage converter 50 and supplies the voltage to the assembled battery 10. Thereby, the assembled battery 10 will be charged. As described above, the vehicle control device 30 monitors the voltage of the assembled battery 10 based on the state of charge of the assembled battery 10 acquired from the power supply monitoring device 23, and executes control according to the monitoring result.

<2. Configuration of power monitoring device>
Next, the configuration of the power supply monitoring device 23 will be described. FIG. 2 is a block diagram illustrating a configuration example of the power supply monitoring device 23. In FIG. 2, the satellite substrate 22, the communication line L1, and the like are omitted. In FIG. 2, for convenience of understanding, one of the plurality of blocks 11 is shown. In the following, one of the two battery stacks 12 in the block 11 is referred to as “first stack 12a”, and the other. May be referred to as “second stack 12b”.

  The power supply monitoring device 23 is, for example, an electronic control unit (ECU), and includes a voltage detection circuit unit 24, an A / D conversion unit 25, and a control unit 26 as shown in FIG. The voltage detection circuit unit 24 includes a circuit for detecting each stack voltage and detecting deterioration of insulation resistance.

  Here, for example, if the voltage detection circuit unit 24 has a configuration in which a circuit for detecting each stack voltage and a circuit for detecting insulation resistance deterioration are separately provided, the configuration of the power supply monitoring device 23 is complicated. As a result, the cost may increase.

  Therefore, in the power supply monitoring device 23 according to the present embodiment, it is possible to detect each stack voltage and to detect deterioration of the insulation resistance while suppressing the increase in cost by simplifying the configuration of the device. Hereinafter, the configuration of the power supply monitoring device 23 will be described in more detail.

  FIG. 3 is a diagram illustrating a configuration example of the voltage detection circuit unit 24 of the power supply monitoring device 23. As shown in FIG. 3, the voltage detection circuit unit 24 includes first and second capacitors C1 and C2, a first switch S1 to a sixth switch S6, a changeover switch S7, a first resistor R1 to a seventh resistor R7. Is provided. The assembled battery 10 includes an insulation resistance Rp on the positive electrode side and an insulation resistance Rn on the negative electrode side.

  In the voltage detection circuit unit 24, a flying capacitor method is applied, and as described later, after the first capacitor C1 is charged with the voltage of each stack 12a, 12b, the voltage of the first capacitor C1 is set to the voltage of each stack 12a, 12b. It is detected as a voltage.

  Specifically, the voltage detection circuit unit 24 is divided into a charge side circuit and a discharge side circuit via first and second capacitors C1 and C2. Hereinafter, the first and second capacitors C1 and C2 may be collectively referred to as “capacitor C”.

  The charging side circuit is a part including a path in which the stacks 12a and 12b of the assembled battery 10 and the capacitor C are connected and the voltage of the stacks 12a and 12b is charged to the capacitor C. The discharge side circuit is a part including a path for discharging the voltage charged in the capacitor C.

  Then, charging and discharging of the capacitor C are controlled by controlling on / off of the switches S1 to S7. As each of the switches S1 to S7 described above, for example, a solid state relay (SSR) can be used. However, the present invention is not limited to this. The first resistor R1 to the seventh resistor R7 are voltage detection resistors for detecting the voltage of the capacitor C.

  In the charging side circuit of the voltage detection circuit unit 24, each of the first stack 12 a and the second stack 12 b is connected in parallel to the capacitor C. That is, both ends of the capacitor C are connected to the positive and negative electrodes of the first stack 12a, and are also connected to the positive and negative electrodes of the second stack 12b.

  In addition, a first resistor R1, a first switch S1, and a fifth resistor R5 are provided in series between the positive side of the first stack 12a and the capacitor C, and the negative side of the first stack 12a and the capacitor C are connected to each other. A second resistor R2 and a second switch S2 are provided in series between them.

  A third resistor R3, a third switch S3, and a fifth resistor R5 are provided in series between the positive electrode side of the second stack 12b and the capacitor C, and the negative electrode side of the second stack 12b and the capacitor C are connected to each other. A fourth resistor R4 and a fourth switch S4 are provided in series between them.

  In the discharge side circuit of the voltage detection circuit unit 24, a fifth switch S5 is provided in the path on the positive electrode side of the first stack 12a and the second stack 12b, and a fifth switch S5 is provided between one end of the fifth switch S5 and the capacitor C. A resistor R5 is provided. In addition, a sixth switch S6 is provided in the path on the negative electrode side of the first and second stacks 12a and 12b, and one end of the sixth switch S6 is connected to the capacitor C.

  The other end of the fifth switch S5 is connected to the A / D conversion unit 25 and is branched in the middle to be connected to the vehicle body GND via the sixth resistor R6. The other end of the sixth switch S6 is connected to the vehicle body GND via a seventh resistor R7. The vehicle body GND is an example of a ground point.

  The A / D conversion unit 25 converts an analog value indicating a voltage at the connection point A of the voltage detection circuit unit 24 into a digital value, and outputs the converted digital value to the control unit 26.

  Next, the first and second capacitors C1 and C2 will be described in detail. Since it is desirable that the voltage detection processing of each of the stacks 12a and 12b described above be completed in a relatively short time, in the capacitor used for voltage detection, the capacitance is compared so that it can be charged in a short time. Smaller is preferable.

  On the other hand, it is preferable that the capacitor used for detecting the deterioration of the insulation resistances Rp and Rn has a relatively large capacitance. That is, the vehicle has a stray capacitance that is not intended at the time of design. When detecting the deterioration of the insulation resistances Rp and Rn, if the influence of the stray capacitance is received, there is a possibility that the voltage of the capacitor cannot be accurately detected, and the accuracy of the deterioration detection may be lowered. Therefore, it is preferable to reduce the influence of the stray capacitance on the overall capacitance by relatively increasing the capacitance of the capacitor used for detecting the deterioration of the insulation resistances Rp and Rn.

  Therefore, in the present embodiment, the first and second capacitors C1 and C2 are configured as follows. Specifically, the first capacitor C1 is connected in series with the fifth resistor R5. The second capacitor C2 is connected in series with the changeover switch S7.

  The second capacitor C2 and the changeover switch S7 are connected in parallel to the first capacitor C1. Therefore, by controlling on / off of the changeover switch S7, the capacitors connected in the charge side circuit and the discharge side circuit can be easily switched, and thus the overall capacitance in each circuit can be made variable. it can.

  Specifically, for example, when the change-over switch S7 is turned off during the voltage detection process of each of the stacks 12a and 12b, only the first capacitor C1 is connected in the charge side circuit and the discharge side circuit. Processing is performed with a small capacitance.

  On the other hand, when the changeover switch S7 is turned on during the process of detecting the deterioration of the insulation resistances Rp and Rn, the first and second capacitors C1 and C2 are connected in the charge side circuit and the discharge side circuit. Processing is performed with a large capacitance.

  Here, the capacitance of the second capacitor C2 is larger than the stray capacitance. Specifically, when the stray capacitance of the vehicle is about 0.1 μF, the capacitance of the second capacitor C2 is set to 2.2 μF, which is about 20 times. In such a case, the capacitance of the first capacitor C1 is, for example, 0.165 μF. Thus, the capacitance of the second capacitor C2 is larger than the capacitance of the first capacitor.

  As a result, it is possible to further increase the capacitance of the capacitor used for detecting the deterioration of the insulation resistances Rp and Rn, that is, the combined capacitance of the first and second capacitors C1 and C2. The influence of capacity can be further reduced.

  Thus, the first capacitor C1 is used for both voltage detection of the stacks 12a and 12b and detection of deterioration of the insulation resistances Rp and Rn. The second capacitor C2 is used for detecting deterioration of the insulation resistances Rp and Rn.

  Next, charging and discharging of the voltage detection circuit unit 24 configured as described above will be described. First, charging and discharging of the first capacitor C1 performed to detect the voltages of the first and second stacks 12a and 12b will be described with reference to FIGS.

  FIG. 4 is a diagram illustrating a charging path for charging the first capacitor C1 with the voltage of the first stack 12a. FIG. 5 is a diagram showing a discharge path for discharging the charged first capacitor C1, and FIG. 6 is a diagram showing a charge path for charging the first capacitor C1 with the voltage of the second stack 12b. is there.

  In the power supply monitoring device 23, the first capacitor C1 is charged for each of the first and second stacks 12a and 12b. First, an example of charging the first capacitor C1 with the voltage of the first stack 12a (hereinafter sometimes referred to as “first stack voltage”) will be described. As shown in FIG. The switch S2 is turned on and the other switches S3 to S7 are turned off.

  Accordingly, the positive side of the first stack 12a is connected to the negative electrode of the first stack 12a via the first resistor R1, the first switch S1, the fifth resistor R5, the first capacitor C1, the second switch S2, and the second resistor R2. Connected with the side. That is, a first path P1 connecting the first stack 12a and the first capacitor C1 is formed, and the first stack voltage is charged in the first capacitor C1.

  Then, after a predetermined time has elapsed since the formation of the first path P1, the voltage of the first capacitor C1 is discharged. Specifically, as shown in FIG. 5, the first switch S1 and the second switch S2 are turned off, and the fifth switch S5 and the sixth switch S6 are turned on.

  As a result, a second path P <b> 2 that is a discharge path is formed in the voltage detection circuit unit 24. Since the A / D converter 25 is connected to the other end of the fifth switch S5, when the second path P2 is formed, the voltage of the first capacitor C1 (that is, the first stack voltage) is A / D converted. Input to the unit 25. The A / D converter 25 converts an analog value input at the moment when the fifth and sixth switches S5 and S6 are turned on into a digital value and outputs the digital value to the controller 26. As a result, the first stack voltage is detected.

  Next, an example in which the first capacitor C1 is charged with the voltage of the second stack 12b (hereinafter sometimes referred to as “second stack voltage”) will be described. As shown in FIG. 6, the third switch S3 and the fourth switch S4 are turned on, and the other switches S1, S2, S5 to S7 are turned off.

  Accordingly, the positive side of the second stack 12b is connected to the negative electrode of the second stack 12b via the third resistor R3, the third switch S3, the fifth resistor R5, the first capacitor C1, the fourth switch S4, and the fourth resistor R4. Connected with the side. That is, a third path P3 connecting the second stack 12b and the first capacitor C1 is formed, and the second stack voltage is charged in the first capacitor C1. The first and third paths P1 and P3 described above are examples of the first charging path.

  Then, after a predetermined time has elapsed since the formation of the third path P3, the third and fourth switches S3 and S4 are turned off, and the fifth and sixth switches S5 and S6 are turned on. The voltage of C1 is discharged (see FIG. 5).

  As a result, a second path P <b> 2 is formed in the voltage detection circuit unit 24, and the voltage of the first capacitor C <b> 1 (that is, the second stack voltage) is input to the A / D conversion unit 25. Then, the A / D converter 25 converts the analog value of the input voltage into a digital value and outputs it to the controller 26 in the same manner as described above. As a result, the second stack voltage is detected.

  In this way, the first stack voltage and the second stack voltage can be detected by switching between the discharge side path and the charge side path to charge and discharge the first capacitor C1.

  In the first and second stack voltage detection processing, the first capacitor C1 does not need to be fully charged. That is, for example, in the first and second stack voltage detection processing, charging is performed for a predetermined time shorter than the time required for full charge, and the first and second stack voltages are estimated based on the charging voltage. May be. Thereby, the detection processing time of the first and second stack voltages can be shortened.

  Further, as shown in FIG. 3, the circuit of the voltage detection circuit unit 24 is provided with an insulation resistance Rp on the positive electrode side and an insulation resistance Rn on the negative electrode side of the assembled battery 10 described above. Each of the insulation resistances Rp and Rn indicates a combined resistance of the mounted resistance and a resistance that virtually represents the insulation with respect to the vehicle body GND. Here, the mounted resistance and the virtual resistance It doesn't matter which one.

  The resistance value of each of the insulation resistances Rp and Rn is set to a sufficiently large value, for example, several MΩ, so that almost no current is supplied in a normal state. However, when the insulation resistances Rp and Rn are deteriorated abnormally, for example, the assembled battery 10 is short-circuited to the vehicle body GND or the like, or the resistance value is reduced to such an extent that the battery is energized in a state close to a short circuit.

  Here, charging and discharging of the capacitor C (that is, the first and second capacitors C1 and C2) performed to detect deterioration of the insulation resistances Rp and Rn of the assembled battery 10 will be described with reference to FIGS. explain.

  FIG. 7 is a diagram illustrating a charging path when detecting deterioration of the insulation resistance Rp on the positive electrode side of the assembled battery 10. FIG. 8 is a diagram showing a discharge path for discharging the charged capacitor C, and FIG. 9 is a diagram showing a charge path when detecting the deterioration of the insulation resistance Rn on the negative electrode side of the assembled battery 10. is there.

  First, when detecting the deterioration of the positive-side insulation resistance Rp, as shown in FIG. 7, the fourth switch S4, the fifth switch S5 and the changeover switch S7 are turned on, and the other switches S1 to S3 and S6 are turned off. Is done. As a result, the positive side of the first stack 12a passes through the insulation resistance Rp, the sixth resistance R6, the fifth switch S5, the fifth resistance R5, the capacitor C, the fourth switch S4, the fourth resistance R4, and the second stack 12b. Are connected to the negative electrode side of the first stack 12a.

  That is, a fourth path P4 that connects the first and second stacks 12a and 12b and the capacitor C via the positive-side insulation resistance Rp is formed. At this time, when the resistance value of the insulation resistance Rp is normal, the fourth path P4 hardly conducts, and when the insulation resistance Rp deteriorates and the resistance value decreases, the fourth path P4 It will be conducted.

  Then, after a predetermined time has elapsed since the formation of the fourth path P4, the voltage of the capacitor C is discharged. Specifically, as shown in FIG. 8, the fourth switch S4 is turned off and the sixth switch S6 is turned on. As a result, a fifth path P5, which is a discharge path, is formed in the voltage detection circuit unit 24. The voltage of the capacitor C detected at this time is “voltage VRp”, and deterioration of the insulation resistance Rp is detected based on the voltage VRp, which will be described later.

  When detecting the deterioration of the negative-side insulation resistance Rn, as shown in FIG. 9, the first switch S1, the sixth switch S6, and the changeover switch S7 are turned on, and the other switches S2 to S5 are turned off. As a result, the positive side of the first stack 12a passes through the first resistor R1, the first switch S1, the fifth resistor R5, the capacitor C, the sixth switch S6, the seventh resistor R7, the insulation resistor Rn, and the second stack 12b. Are connected to the negative electrode side of the first stack 12a.

  That is, a sixth path P6 is formed that connects the first and second stacks 12a and 12b and the capacitor C via the negative-side insulation resistance Rn. At this time, when the resistance value of the insulation resistance Rn is normal, the sixth path P6 hardly conducts. When the insulation resistance Rn deteriorates and the resistance value decreases, the sixth path P6 It will be conducted.

  Then, after a predetermined time has elapsed since the sixth path P6 was formed, the voltage of the capacitor C is discharged as shown in FIG. The voltage of the capacitor C detected at this time is “voltage VRn”, and the deterioration of the insulation resistance Rn is detected based on the voltage VRn, which will be described later. The fourth and sixth paths P4 and P6 described above are examples of the second charging path.

  In the deterioration detection process of the insulation resistances Rp and Rn, the battery is charged for a predetermined time shorter than the time required for full charge, and the charge voltage is used as the voltages VRp and VRn to detect the deterioration of the insulation resistances Rp and Rn. I do.

  Returning to the description of FIG. 2, the control unit 26 of the power supply monitoring device 23 is a microcomputer including a CPU, a RAM, a ROM, and the like, and includes a voltage detection circuit unit 24, an A / D conversion unit 25, and the like. 23 is controlled.

  Specifically, the control unit 26 includes a charge / discharge path forming unit 26a, a voltage detection unit 26b, and a power supply monitoring unit 26c. The charge / discharge path forming unit 26a forms first, third, fourth, and sixth paths P1, P3, P4, and P6 that are charge paths, or second and fifth paths P2 and P5 that are discharge paths. .

  Specifically, the charge / discharge path forming unit 26a includes first to sixth switch control units 26a1 and a capacitor switching unit 26a2. The first to sixth switch control units 26a1 control the first to sixth switches S1 to S6 to form a charging path or a discharging path.

  And capacitor switching part 26a2 controls changeover switch S7, and switches the capacitor connected in a charge course or a discharge course. Specifically, the capacitor switching unit 26a2 controls the changeover switch S7 so that the charging path (first and third paths P1, P3) including the first capacitor C1 without including the second capacitor C2, and the first, Switching is performed between charging paths (fourth and sixth paths P4 and P6) including the second capacitors C1 and C2.

  Similarly, at the time of discharging, the capacitor switching unit 26a2 controls the changeover switch S7 so that the discharge path (second path P2) including the first capacitor C1 without including the second capacitor C2, and the first and second Switching is made between the discharge paths (the fifth path P5) including the capacitors C1 and C2.

  Note that the switching patterns of the first to sixth switches S1 to S6 and the changeover switch S7 are stored in advance in a storage unit such as a RAM and a ROM. Then, the charging / discharging path forming unit 26a reads the switching pattern from the storage unit at an appropriate timing, thereby forming a charging path or a discharging path.

  When the discharge path is formed by the charge / discharge path forming unit 26a, the voltage detection unit 26b detects the charged voltage of the first capacitor C1 or the like via the A / D conversion unit 25. The voltage detector 26b detects the first and second stack voltages and the voltages VRp and VRn.

  Then, the voltage detection unit 26b outputs a signal indicating the detected first and second stack voltages and the like to the power supply monitoring unit 26c.

  The power monitoring unit 26c monitors the charge states of the first and second stacks 12a and 12b based on the first and second stack voltages. And the power supply monitoring part 26c outputs the information which shows the monitoring result of the charge condition of the assembled battery 10 containing the 1st, 2nd stack 12a, 12b to the vehicle control apparatus 30 (refer FIG. 1). In addition, the vehicle control apparatus 30 performs vehicle control according to the monitoring result of the charge condition of the assembled battery 10, as described above.

  The power supply monitoring unit 26c further detects deterioration of the insulation resistances Rp and Rn based on the voltages VRp and VRn of the capacitor C.

  Specifically, when the insulation resistance Rp and the insulation resistance Rn are not deteriorated and the resistance value is not lowered, the capacitor C is hardly charged or even if it is charged, a sufficiently small voltage is charged. . Therefore, the power supply monitoring unit 26c compares the voltage VRp and the voltage VRn with a threshold value Va set in advance to a relatively low value.

  Then, when the voltage VRp of the capacitor C becomes equal to or higher than the threshold value Va, the power supply monitoring unit 26c detects deterioration of the insulation resistance Rp, in other words, determines that an abnormality has occurred in the insulation resistance Rp. On the other hand, when the voltage VRp is less than the threshold value Va, the power supply monitoring unit 26c determines that the insulation resistance Rp is not deteriorated, in other words, the insulation resistance Rp is normal.

  Similarly, the power supply monitoring unit 26c detects the deterioration of the insulation resistance Rn when the voltage VRn is equal to or higher than the threshold value Va, while the insulation resistance Rn is not deteriorated when the voltage VRn is less than the threshold value Va. Is determined. In the above description, the values to be compared with the voltages VRn and VRp are the same threshold value Va. However, the present invention is not limited to this, and threshold values set to different values may be used.

  And the power supply monitoring part 26c outputs the information which shows the result of the deterioration state of above-described insulation resistance Rp, Rn to the vehicle control apparatus 30 grade | etc.,. And the vehicle control apparatus 30 performs the vehicle control according to a degradation state, the alerting | reporting operation | movement to a user, etc.

  As described above, the power supply monitoring unit 26c determines the stack voltage based on the voltage of the capacitor charged in the first and third paths P1 and P3 or the fourth and sixth paths P4 and P6 switched by the capacitor switching unit 26a2. Detection and detection of deterioration of the insulation resistances Rp and Rn are performed.

  Specifically, the power supply monitoring unit 26c detects the stack voltage in the first and third paths P1 and P3, and detects the deterioration of the insulation resistances Rp and Rn in the fourth and sixth paths P4 and P6. Monitor the power status.

  Therefore, the power supply monitoring device 23 can be switched to a charging path having a different overall capacitance with a simple configuration that only controls the changeover switch S7, and can detect the stack voltage and the deterioration of the insulation resistances Rp and Rn. Both can be performed accurately.

  In addition, since the voltage detection circuit unit 24 of the power supply monitoring device 23 has a common circuit configuration other than the capacitor, it is possible to detect the stack voltage and the deterioration of the insulation resistances Rp and Rn with a simpler configuration. it can.

  Further, in the power supply monitoring device 23, since the current continues to flow when detecting the stack voltage and detecting the deterioration of the insulation resistances Rp and Rn, it can be made less susceptible to noise.

<3. Specific operation of charge state monitoring process and deterioration detection process>
Next, specific operations of the charge state monitoring process and the deterioration detection process performed by the power supply monitoring system 20 configured as described above will be described with reference to FIG. FIG. 10 is a flowchart illustrating a part of a processing procedure of processing executed by the power supply monitoring system 20. Various processes shown in FIG. 10 are executed based on control by the control unit 26 of the power supply monitoring device 23.

  As shown in FIG. 10, the control unit 26 first controls the changeover switch S7 and the like to form the first path P1 (step S1). Next, after a predetermined time has elapsed, the control unit 26 forms the second path P2 and detects the first stack voltage (step S2).

  Subsequently, the control unit 26 controls the changeover switch S7 and the like to form the fourth path P4 (Step S3), and after a predetermined time has elapsed, forms the fifth path P5 and detects the voltage VRp of the capacitor C (Step S3). S4).

  Next, the control unit 26 controls the changeover switch S7 and the like to form the third path P3 (step S5). Then, after a predetermined time has elapsed, the control unit 26 forms the second path P2 and detects the second stack voltage (step S6).

  Subsequently, the control unit 26 controls the changeover switch S7 and the like to form the sixth path P6 (Step S7), and after a predetermined time has elapsed, forms the fifth path P5 and detects the voltage VRn of the capacitor C (Step S7). S8).

  Then, the control unit 26 detects deterioration of the insulation resistances Rp and Rn based on the voltages VRp and VRn of the capacitor C detected in steps S4 and S8 (step S9). Next, the control unit 26 uses the vehicle control device 30 as information indicating the deterioration state of the insulation resistances Rp and Rn as the deterioration detection result and information indicating the first and second stack voltages as the monitoring result of the charge state of the assembled battery 10. (Step S10).

  In the above description, the first stack voltage, the voltage VRp, the second stack voltage, and the voltage VRn are detected in this order. However, this is only an example, and the detection order is arbitrarily set. can do.

  As described above, the power supply monitoring device 23 according to the embodiment includes the first and second capacitors C1 and C2, the capacitor switching unit 26a2, and the power supply monitoring unit 26c. The first capacitor C1 is used for voltage detection of the power supply. The second capacitor C2 is connected to the first capacitor C1 via the changeover switch S7, and is used for detecting deterioration of the insulation resistances Rp and Rn.

  The capacitor switching unit 26a2 controls the changeover switch S7 to include the first charging path (first and third paths P1, P3) including the first capacitor C1 without including the second capacitor C2, and the second capacitor C2. Is switched between the second charging paths (fourth and sixth paths P4, P6) including at least Based on the voltage of the capacitor charged in the first charging path or the second charging path, the power supply monitoring unit 26c detects the voltage of the power source in the case of the first charging path, and detects the insulation resistances Rp and Rn in the case of the second charging path. Detect degradation and monitor power status.

  Thereby, it is possible to detect the power supply voltage and the deterioration of the insulation resistances Rp and Rn while simplifying the configuration of the power supply monitoring device 23 and suppressing an increase in cost.

  In the above-described embodiment, the positions and the number of the first capacitor C1, the second capacitor C2, the changeover switch S7, etc. are examples and are not limited. That is, the positions of the first and second capacitors C1 and C2 change the overall capacitance between the charging path for detecting the power supply voltage and the charging path for detecting the deterioration of the insulation resistances Rp and Rn. As long as it is possible, it may be anything.

  For example, in the voltage detection circuit unit 24, a switch connected in series with the first capacitor C1 and connected in parallel with the second capacitor C2 and the changeover switch S7 is newly provided. Then, the switch and changeover switch S7 may be controlled to switch between a charging path including only the first capacitor C1 and a charging path including only the second capacitor C2.

  In the voltage detection circuit unit 24, for example, the second capacitor C2 and the changeover switch S7 are connected in series to the first capacitor C1. Further, a switch connected in parallel to the first capacitor C1 and the changeover switch S7 is provided. Then, the switch and the changeover switch S7 may be controlled to switch between a charging path including first and second capacitors C1 and C2 connected in series and a charging path including only the second capacitor C2.

  Further, in the above-described detection of the deterioration of the insulation resistances Rp and Rn, the voltage VRp and the voltage VRn of the capacitor C are respectively compared with the threshold value Va. However, the present invention is not limited to this. That is, for example, the voltage VRp and the voltage VRn may be added and the added voltage may be compared with another preset threshold value to detect deterioration of the insulation resistances Rp and Rn.

  Moreover, the timing which performs the degradation detection process of insulation resistance Rp, Rn is not limited to the above. That is, for example, when the vehicle is started or stopped, the timing for executing the deterioration detection process may be changed, such as every predetermined time interval or every predetermined travel distance.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Charging / discharging system 10 Assembly battery 12a 1st stack 12b 2nd stack 20 Power supply monitoring system 23 Power supply monitoring apparatus 24 Voltage detection circuit part 25 A / D conversion part 26 Control part 26a Charging / discharging path | route formation part 26a1 1st-6th switch Control unit 26a2 Capacitor switching unit 26b Voltage detection unit 26c Power supply monitoring unit 30 Vehicle control device 40 Motor 50 Voltage converter 60 Fail-safe relay C1 First capacitor C2 Second capacitor

Claims (4)

A first capacitor connected to an isolated power source and used for voltage detection of the power source;
A second capacitor connected to the power source and connected to the first capacitor via a changeover switch and used for detecting deterioration of insulation resistance of the power source;
A capacitor switching unit that controls the changeover switch to switch between a first charging path including the first capacitor without including the second capacitor, and a second charging path including at least the second capacitor;
Based on the voltage of the capacitor charged in the first charging path or the second charging path switched by the capacitor switching unit, the voltage of the power source is detected in the first charging path, and the voltage of the second charging path is detected. And a power monitoring unit that detects deterioration of the insulation resistance of the power supply and monitors the state of the power supply. The second capacitor is
The power supply monitoring device according to claim 1, wherein the power supply monitoring device is connected in series to the changeover switch and connected in parallel to the first capacitor. The second capacitor is
The power monitoring apparatus according to claim 1, wherein an electrostatic capacity is larger than an electrostatic capacity of the first capacitor. The changeover switch provided between the first capacitor used for voltage detection of the insulated power supply and the second capacitor used for detection of deterioration of the insulation resistance of the power supply is controlled so that the second capacitor is not included. A capacitor switching step of switching between a first charging path including a first capacitor and a second charging path including at least the second capacitor;
Based on the voltage of the capacitor charged in the first charging path or the second charging path switched in the capacitor switching step, the voltage of the power source is detected in the first charging path, and the second charging path And a power supply monitoring step of detecting deterioration of the insulation resistance of the power supply and monitoring the state of the power supply.

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