JP2018017683A - Power source monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power source monitoring device which can reduce the time required for voltage detecting processing.SOLUTION: The power source monitoring device includes: a capacitor, a non-insulating switching element, and an insulating switching element. The capacitor is charged by a power source and is used at least for monitoring the voltage of the power source. The non-insulating switching element is provided in a discharge passage for discharging the charged capacitor. The non-insulating switching element is connected to the gate terminal of the non-insulating switching element.SELECTED DRAWING: Figure 6A

Description

  The present invention relates to a power supply monitoring device.

  Conventionally, for example, a vehicle such as a hybrid vehicle or an electric vehicle includes a power source that supplies electric power to a motor that is a power source. Various devices for monitoring the state of the power supply have been proposed (see, for example, Patent Document 1).

  In the power supply monitoring apparatus described above, the power supply voltage, which is one of the power supply states, is detected using the flying capacitor method. Specifically, in the power supply monitoring device, the capacitor is charged by energizing the capacitor from the power supply, and the power supply voltage is detected based on the charged voltage of the capacitor.

  Further, in the power supply monitoring device, after the detection of the power supply voltage is completed, the capacitor is connected to the discharge path via the switching element in preparation for the next voltage detection or the like, and the charged capacitor is discharged. A series of voltage detection processing is completed. In the power supply monitoring device described above, an insulating switching element such as a photo-MOSFET (metal-oxide-semiconductor field-effect transistor) is used as a switching element for the discharge path in order to ensure insulation of the power supply with respect to the vehicle body. ing.

JP 2011-17586 A

  However, since the insulating type switching element has a relatively low current (rated current) that can flow, the above-described power supply monitoring device is provided with, for example, a discharge resistor for reducing the current flowing through the switching element in the discharge path. It was. For this reason, in the prior art, it takes time to discharge the capacitor, and there is room for improvement in terms of shortening the time for voltage detection processing.

  The present invention has been made in view of the above, and an object of the present invention is to provide a power supply monitoring apparatus capable of reducing the time required for voltage detection processing.

  In order to solve the above-described problems and achieve the object, the present invention includes a capacitor, a non-insulating switching element, and an insulating switching element in a power supply monitoring device. The capacitor is charged by a power source and used at least for voltage monitoring of the power source. The non-insulating switching element is provided in a discharge path for discharging the charged capacitor. The insulating switching element is connected to the gate terminal of the non-insulating switching element.

  According to the present invention, the time required for the voltage detection process can be shortened in the power supply monitoring device.

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 capacitor with the voltage of the first stack. FIG. 5 is a diagram showing a discharge path for detecting the voltage of the charged capacitor. FIG. 6A is a diagram (part 1) illustrating a discharge path in which only the capacitor is discharged. FIG. 6B is a diagram (part 2) illustrating a discharge path in which only the capacitor is discharged. FIG. 7 is a diagram illustrating a charging path for charging the capacitor with the voltage of the second stack. FIG. 8 is a diagram illustrating a charging path when detecting deterioration of the insulation resistance Rp on the positive electrode side of the assembled battery. FIG. 9 is a diagram illustrating a charging path when detecting deterioration of the insulation resistance Rn on the negative electrode side of the assembled battery. FIG. 10A is a diagram (No. 1) illustrating a discharge path in which only a capacitor charged with a negative voltage is discharged. FIG. 10B is a diagram (part 2) illustrating a discharge path in which only the capacitor charged with the negative voltage is discharged. FIG. 11 is a flowchart illustrating a part of a processing procedure of processing executed by the power supply monitoring system. FIG. 12 is a diagram for explaining a part of processing executed by the power supply monitoring system.

  Hereinafter, an embodiment of a power supply monitoring device 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 communication line L2, The state of charge of the assembled 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 as shown in FIG. 2, a voltage detection circuit unit 24, an A / D conversion unit 25, a voltage detection circuit unit 24, and an A / D And a control unit 26 that controls the entire power supply monitoring device 23 including the D conversion unit 25 and the like.

  The voltage detection circuit unit 24 includes a circuit for detecting each stack voltage and detecting leakage due to deterioration of insulation resistance. Here, the voltage detection circuit unit 24 will be described in detail with reference to FIG.

  FIG. 3 is a diagram illustrating a configuration example of the voltage detection circuit unit 24. As shown in FIG. 3, the voltage detection circuit unit 24 includes a capacitor C, a first switch S1 to a sixth switch S6, a first resistor R1 to a seventh resistor R7, and non-insulating switching elements M1 and M2. , An insulating switching element SW, and first and second diodes D1 and D2. 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 capacitor C is charged with the voltage of each stack 12a, 12b, the voltage of the capacitor C is detected as the voltage of each stack 12a, 12b. ing.

  Specifically, the voltage detection circuit unit 24 is divided into a charge side circuit and a discharge side circuit via a 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.

  The controller 26 controls on / off of the switches S1 to S6, the non-insulating switching elements M1 and M2, and the insulating switching element SW, thereby controlling charging and discharging of the capacitor C. .

  Hereinafter, the non-insulating switching element M1 may be referred to as “first non-insulating element M1”, and the non-insulating switching element M2 may be referred to as “second non-insulating element M2”. Further, the insulating switching element SW may be referred to as “insulating element SW”.

  In addition, as each above-mentioned switch S1-S6, although a solid state relay (SSR: Solid State Relay) can be used, for example, it is not limited to this. The first resistor R1 to the sixth resistor R6 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.

  A first resistor R1 and a first switch S1 are provided in series between the positive electrode side of the first stack 12a and the capacitor C, and a first resistor R1 and a first switch S1 are provided between the negative electrode side of the first stack 12a and the capacitor C. Two resistors R2 and a second switch S2 are provided in series.

  A third resistor R3 and a third switch S3 are provided in series between the positive electrode side of the second stack 12b and the capacitor C, and the second resistor 12b is connected in series between the negative electrode side of the second stack 12b and the capacitor C. A four resistor R4 and a fourth switch S4 are provided in series.

  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 the first switch is provided between one end of the fifth switch S5 and the capacitor C. The drain terminal of the non-insulated element M1 is connected.

  In addition, a sixth switch S6 is provided in the negative-side path of the first and second stacks 12a and 12b, and the drain terminal of the second non-insulated element M2 is provided between one end of the sixth switch S6 and the capacitor C. Is connected.

  The source terminal of the first non-insulated element M1 is connected to the source terminal of the second non-insulated element M2. Thus, the first non-insulated element M1 and the second non-insulated element M2 are connected in series between the positive path and the negative path of the first and second stacks 12a and 12b.

  Each of the first non-insulated element M1 and the second non-insulated element M2 includes parasitic diodes M1a and M2a each having an anode connected to the source terminal and a cathode connected to the drain terminal.

  Since the first and second non-insulating elements M1 and M2 are connected as described above, from the path on the negative electrode side to the path on the negative electrode side and the path on the negative electrode side of the first and second stacks 12a and 12b. It is possible to conduct in both directions of the path on the positive electrode side. Note that this bidirectional conduction will be described later with reference to FIGS. 6A and 10A.

  For example, MOSFETs can be used as the first and second non-insulated elements M1 and M2, but the present invention is not limited to this. The first and second non-insulated elements M1 and M2 such as MOSFETs are set so that the rated current indicating the current that can flow is higher than that of non-insulated switching elements such as photo MOSFETs. .

  Capacitors C are connected to the gate terminals of the first and second non-insulated elements M1 and M2 via the insulating elements SW and the like, whereby the first and second non-insulated elements M1 and M2 are The charged voltage of the capacitor C is supplied and can be driven.

  Specifically, the gate terminals of the first and second non-insulating elements M1 and M2 are both connected to the insulating element SW. As the insulating element SW, for example, a photocoupler can be used, but is not limited thereto, and may be a photo MOSFET or the like.

  Insulated element SW that is a photocoupler includes a bipolar transistor, and the gate terminals of the first and second non-insulated elements M1 and M2 are connected to the emitter of the bipolar transistor.

  In the insulated element SW, the collector of the bipolar transistor is connected to the cathode of the first diode D1 and the cathode of the second diode D2. The anode of the first diode D1 is connected to the path on the positive side of the first and second stacks 12a and 12b, while the anode of the second diode D2 is the path on the negative side of the first and second stacks 12a and 12b. Connected to.

  In other words, the anode of the first diode D1 is connected between one end of the fifth switch S5 and the capacitor C. On the other hand, the anode of the second diode D2 is connected between one end of the sixth switch S6 and the capacitor C. The first and second non-insulated elements M1 and M2 are connected as described above to be driven by being supplied with the voltage of the charged capacitor C. This is illustrated in FIGS. 6A and 10A. Will be described later.

  As described above, in the voltage detection circuit unit 24, since the insulating element SW is used as an element for driving the first and second non-insulating elements M1 and M2, the first and second stacks 12a, Insulation with respect to the vehicle body (not shown) of 12b and capacitor C can be secured.

  Further, the insulating element SW is further connected between the first non-insulating element M1 and the second non-insulating element M2 connected in series. Specifically, in the insulating element SW, the emitter of the bipolar transistor is interposed between the source terminal of the first non-insulating element M1 and the source terminal of the second non-insulating element M2 via the seventh resistor R7. Connected.

  As a result, for example, even when the voltage of the capacitor C drops during discharging and the first and second non-insulated elements M1 and M2 are turned off, the discharging of the capacitor C can be continued. This will be described later with reference to FIGS. 6B and 10B.

  The seventh resistor R7 is connected to the first non-isolated element M1 and the second non-insulated element when the voltage of the capacitor C is not supplied to the gate terminals of the first and second non-insulated elements M1 and M2. This is a resistor for setting the mold element M2 to the same potential.

  Continuing the description of the voltage detection circuit unit 24, the other end of the fifth switch S5 is connected to the A / D conversion unit 25, and branched in the middle to be connected to the vehicle body GND via the fifth resistor R5. . The other end of the sixth switch S6 is connected to the vehicle body GND via a sixth resistor R6.

  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.

  Here, charging and discharging of the capacitor C performed to detect the voltages of the first and second stacks 12a and 12b will be described.

  In the power supply monitoring device 23 according to the present embodiment, as voltage detection processing, the capacitor C is first charged with the voltage of the first stack 12a or the second stack 12b, and then the charged capacitor C is charged with voltage. The voltage is detected by connecting to a discharge path for detection. Subsequently, in the power supply monitoring device 23, in preparation for the next processing such as voltage detection, the capacitor C is connected to a discharge path where only the discharge is performed, and the discharge is continued. This completes the voltage detection process.

  Charging and discharging of the capacitor C in the power supply monitoring device 23 will be described with reference to FIGS. FIG. 4 is a diagram illustrating a charging path for charging the capacitor C with the voltage of the first stack 12a. FIG. 5 is a diagram illustrating a discharge path for detecting the voltage of the charged capacitor C, and FIGS. 6A and 6B are diagrams illustrating a discharge path in which only the capacitor C is discharged. FIG. 7 is a diagram illustrating a charging path for charging the capacitor C with the voltage of the second stack 12b.

  In the power supply monitoring device 23, the capacitor C is charged for each of the first and second stacks 12a and 12b. First, an example of charging the capacitor C with the voltage of the first stack 12a (hereinafter sometimes referred to as “first stack voltage”) will be described. As shown in FIG. 4, the first switch S1 and the second switch S2 Is turned on, and the other switches S3 to S6, the insulation element SW, and the like are turned off.

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

  Then, after a predetermined time has elapsed since the formation of the first path P1, the voltage of the capacitor C is discharged, and the first stack voltage is detected. That is, the charged capacitor C is connected to a discharge path for detecting a voltage. 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 capacitor C (that is, the first stack voltage) is changed to the A / D converter 25. Is input. 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, the discharge of the capacitor C is completed in preparation for the next processing such as voltage detection. Specifically, the charged capacitor C is connected to a discharge path where only discharging is performed. More specifically, as shown in FIG. 6A, the fifth switch S5 and the sixth switch S6 are turned off, and a drive signal is input to the isolated element SW and turned on.

  Thereby, a discharge path P <b> 10 is formed in the voltage detection circuit unit 24. Specifically, when the insulation type element SW is turned on, first, as shown as a discharge path P11 in FIG. 6A, the voltage of the capacitor C is changed to the first and first levels via the first diode D1 and the insulation type element SW. 2 is supplied to the gate terminals of the non-insulated elements M1 and M2.

  As a result, the first and second non-insulated elements M1 and M2 are turned on, the capacitor C and the first and second non-insulated elements M1 and M2 are conducted, and the discharge path P10 is formed. Accordingly, in the capacitor C, a current flows through the first non-insulated element M1 and the second non-insulated element M2, and discharge is performed.

  Thus, the first and second non-insulated elements M1 and M2 are provided in the discharge path P10, and the rated current is higher than that of the photo MOSFET used in the conventional technique. Therefore, a relatively large amount of current flows from the capacitor C in the discharge path P10, so that the discharge time can be shortened.

  Further, the first and second non-insulated elements M1 and M2 are driven by the charged voltage of the capacitor C being input via the insulated element SW, thereby forming the discharge path P10. As a result, in the power supply monitoring device 23, the voltage of the capacitor C is also used for driving the first and second non-insulated elements M1 and M2, so that the discharge of the capacitor C can be promoted. And the discharge time can be further shortened.

  Further, by configuring as described above, a dedicated power source for driving the first and second non-insulating elements M1 and M2 can be eliminated, and the configuration of the power supply monitoring device 23 can be simplified.

  Subsequently, when the discharge of the capacitor C proceeds, the voltage of the capacitor C decreases, and accordingly, the voltage supplied to the gate terminals of the first and second non-insulated elements M1 and M2 also decreases. When the supply voltage to the gate terminal falls below the threshold value Vref that can drive the first and second non-insulating elements M1 and M2, the first and second non-insulating elements M1 and M2 Thus, the discharge of the capacitor C by the discharge path P10 ends.

  Therefore, in the present embodiment, since the insulated element SW is connected between the first non-insulated element M1 and the second non-insulated element M2 connected in series, the discharge of the capacitor C is continued. be able to.

  Specifically, as shown as the discharge path P12 in FIG. 6B, in the capacitor C, the current flows through the first diode D1, the insulating element SW, the seventh resistor R7, and the parasitic diode M2a of the second non-insulating element M2. It flows and discharges.

  Thus, in the present embodiment, the insulating element SW is connected between the first non-insulating element M1 and the second non-insulating element M2, and the parasitic diode M2a of the second non-insulating element M2 is connected. By using, the discharge of the capacitor C can be continued and the discharge time can be further shortened.

  Next, an example in which the capacitor C 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. 7, the third switch S3 and the fourth switch S4 are turned on, and the other switches S1, S2, S5, S6, the insulation element SW, and the like are turned off.

  Thereby, the positive electrode side of the second stack 12b is connected to the negative electrode side of the second stack 12b via the third resistor R3, the third switch S3, the capacitor C, the fourth switch S4, and the fourth resistor R4. That is, a third path P3 connecting the second stack 12b and the capacitor C is formed, and the capacitor C is charged with the second stack voltage.

  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 is discharged (see FIG. 5).

  As a result, the second path P <b> 2 is formed in the voltage detection circuit unit 24, and the voltage of the capacitor C (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.

  Subsequently, the fifth and sixth switches S5 and S6 are turned off, and the insulating element SW is turned on to complete the discharge of the capacitor C (see FIGS. 6A and 6B).

  In this manner, the first stack voltage and the second stack voltage can be detected by switching the discharge-side path and the charge-side path to charge and discharge the capacitor C.

  In the first and second stack voltage detection processes, the capacitor C 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 performed for detecting deterioration of the insulation resistances Rp and Rn of the assembled battery 10 will be described with reference to FIGS. FIG. 8 is a diagram illustrating a charging path when detecting the deterioration of the insulation resistance Rp on the positive electrode side of the assembled battery 10. FIG. 9 is a diagram showing a charging path when detecting the deterioration of the insulation resistance Rn on the negative electrode side of the assembled battery 10.

  First, when detecting the deterioration of the insulation resistance Rp on the positive side, as shown in FIG. 8, the fourth switch S4 and the fifth switch S5 are turned on, and the other switches S1 to S3, S6, the insulation type element SW, etc. Is turned off. Thus, the positive side of the first stack 12a is connected to the first stack 12a via the insulation resistance Rp, the fifth resistance R5, the fifth switch S5, the capacitor C, the fourth switch S4, the fourth resistance R4, and the second stack 12b. Connected to the negative electrode side.

  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 fourth switch S4 is turned off and the sixth switch S6 is turned on to discharge the voltage of the capacitor C (see FIG. 5). 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.

  Subsequently, the fifth and sixth switches S5 and S6 are turned off, and the insulating element SW is turned on to complete the discharge of the capacitor C (see FIGS. 6A and 6B).

  When detecting the deterioration of the negative-side insulation resistance Rn, as shown in FIG. 9, the first switch S1 and the sixth switch S6 are turned on, and the other switches S2 to S5, the insulation element SW, and the like are turned off. . Accordingly, the positive side of the first stack 12a is connected to the first stack 12a via the first resistor R1, the first switch S1, the capacitor C, the sixth switch S6, the sixth resistor R6, the insulation resistor Rn, and the second stack 12b. Connected to the negative electrode side.

  That is, a fifth path P5 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 fifth path P5 hardly conducts, and when the insulation resistance Rn deteriorates and the resistance value decreases, the fifth path P5 It will be conducted.

  Then, after a predetermined time has elapsed since the fifth path P5 is 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.

  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.

  Subsequently, the fifth and sixth switches S5 and S6 are turned off, the isolated element SW is turned on, and the discharge of the capacitor C is completed, as described above (see FIGS. 6A and 6B).

  Here, the point that the first and second non-insulating elements M1 and M2 can be conducted in both directions will be described in detail. In the charging / discharging system 1 described above, for example, the boost converter 70 (see FIG. 9) may operate in a state where a charging path (fifth path P5) for detecting deterioration of the insulation resistance Rn is formed. . In such a case, for example, depending on the state of the insulation resistance Rn, the operation timing of the boost converter 70, and the like, the body voltage may fluctuate and exceed the voltage of the power supply.

  When the body voltage exceeds the voltage of the power supply, the capacitor C is charged with a negative voltage. Specifically, as shown in FIG. 9, when a current flows in the charging path P5a by the boost converter 70 indicated by an imaginary line and the current in the charging path P5a becomes larger than the current in the fifth path P5, a negative voltage is applied to the capacitor C. It will be charged.

  As described above, even if the capacitor C is charged with a negative voltage, the first and second non-insulated elements M1 and M2 can be conducted in both directions, so that the capacitor C can be discharged. This will be described with reference to FIGS. 10A and 10B.

  10A and 10B are diagrams illustrating a discharge path in which only the capacitor C charged with a negative voltage is discharged.

  In the power supply monitoring device 23, as shown in FIG. 10A, after the voltage of the capacitor C charged with the negative voltage is detected, as shown in FIG. 10A, the fifth switch S5 and the sixth switch The switch S6 is turned off and a drive signal is input to the isolated element SW to turn it on.

  As a result, a discharge path P <b> 10 a is formed in the voltage detection circuit unit 24. Specifically, when the insulation type element SW is turned on, first, as shown in FIG. 10A as the discharge path P11a, the voltage of the capacitor C is changed to the first and first levels via the second diode D2 and the insulation type element SW. 2 is supplied to the gate terminals of the non-insulated elements M1 and M2.

  As a result, the first and second non-insulated elements M1 and M2 are turned on, the capacitor C and the first and second non-insulated elements M1 and M2 are brought into conduction, and the discharge path P10a is formed. Therefore, in the capacitor C, a current flows through the second non-insulated element M2 and the first non-insulated element M1, and discharge is performed.

  Further, when the discharge of the capacitor C progresses, the voltage supplied to the gate terminals of the first and second non-insulated elements M1 and M2 decreases, and the supply voltage to the gate terminals decreases below the above threshold value Vref. The first and second non-insulating elements M1 and M2 are turned off.

  However, in the present embodiment, as described above, the insulating element SW is connected between the first non-insulating element M1 and the second non-insulating element M2 connected in series. Accordingly, as shown as a discharge path P12a in FIG. 10B, in the capacitor C, a current flows through the second diode D2, the insulating element SW, the seventh resistor R7, and the parasitic diode M1a of the first non-insulating element M1 to discharge. Will continue.

  As described above, in the present embodiment, the first and second non-insulated elements M1 and M1 are charged regardless of whether the capacitor C is charged with a positive voltage or the negative voltage. Since M2 can conduct in both directions, the capacitor C can be reliably discharged.

  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. Specifically, the control unit 26 includes a switch control unit 26a, a voltage detection unit 26b, and a power supply monitoring unit 26c.

  The switch control unit 26a controls the operations of the first switch S1 to the sixth switch S6, the non-insulating switching elements M1 and M2, and the insulating switching element SW, and the first, third, and fourth charging paths. The sixth paths P1, P3, P4 and P5, the second path P2 which is the discharge path, and the discharge paths P10 to P12 and P10a to P12a are formed.

  It should be noted that the switching patterns of the first to sixth switches S1 to S6 and the insulation type element SW are stored in advance in a storage unit such as a RAM and a ROM. And the switch control part 26a forms a charge path or a discharge path | route by reading a switching pattern from a memory | storage part at an appropriate timing.

  The voltage detection unit 26b detects the voltage of the charged capacitor C via the A / D conversion unit 25 when the switch control unit 26a forms the second path P2 that is a discharge path. 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 predetermined 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 predetermined value Va, the power supply monitoring unit 26c detects the deterioration of the insulation resistance Rp, in other words, determines that the insulation resistance Rp is abnormal and has a leakage. . On the other hand, when the voltage VRp is less than the predetermined value Va, the power supply monitoring unit 26c determines that there is no deterioration in the insulation resistance Rp, in other words, the insulation resistance Rp is normal and there is no leakage.

  Similarly, when the voltage VRn is equal to or higher than the predetermined value Va, the power supply monitoring unit 26c detects the deterioration of the insulation resistance Rn. On the other hand, when the voltage VRn is lower than the predetermined value Va, the power supply monitoring unit 26c determines that the insulation resistance Rn is not deteriorated. To do. In the above description, the values to be compared with the voltages VRn and VRp are set to the same predetermined 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.

<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 FIGS.

  FIG. 11 is a flowchart illustrating a part of a processing procedure of processing executed by the power supply monitoring system 20. FIG. 12 is a diagram for explaining steps S10 to S12 which are a part of the process shown in FIG. Various processes shown in FIG. 11 are executed based on control by the control unit 26 of the power supply monitoring device 23.

  As shown in FIG. 11, first, the control unit 26 forms the first path P1 and charges the capacitor C (step S10). Next, the control unit 26 forms the second path P2 and detects the first stack voltage (step S11). Then, the control unit 26 controls the insulating element SW to form the discharge paths P10 and P11, and then forms the discharge path P12 to complete the discharge of the capacitor C (step S12).

  The processing in steps S10 to S12 described above will be described in detail with reference to FIG. 12. The control unit 26 turns on the first and second switches S1 and S2 to form the first path P1 at time a1. As a result, the capacitor C is supplied with the first stack voltage and starts charging.

  When a predetermined time elapses and the voltage of the capacitor C reaches, for example, the fully charged value V1 (time a2), the control unit 26 turns off the first and second switches S1 and S2, and the fifth and sixth switches S5. , S6 are turned on to form the second path P2. As a result, the first stack voltage is detected.

  When the detection of the first stack voltage is completed at time a3, the control unit 26 turns on the insulating element SW and forms the discharge path P11, thereby turning on the first and second non-insulating elements M1 and M2. Then, the discharge path P10 is formed. In this way, the capacitor C is discharged.

  As described above, since the first and second non-insulated elements M1 and M2 having a relatively high rated current are provided in the discharge path P10, the discharge of the capacitor C proceeds rapidly, and the voltage of the capacitor C is At time a4, the voltage drops to the threshold value Vref.

  Since the threshold value Vref is a voltage value that can drive the first and second non-insulated elements M1 and M2, when the voltage of the capacitor C becomes equal to or lower than the threshold value Vref at time a4, The second non-insulating elements M1 and M2 are turned off.

  Even when the first and second non-insulated elements M1 and M2 are turned off, the above-described discharge path P12 is formed and the discharge of the capacitor C is continued. Then, the discharge of the capacitor C is completed at time a5.

  Thereafter, at time a6, the control unit 26 turns off the insulating element SW and proceeds to the next voltage detection process. In the illustrated example, the insulation element SW is turned off after the discharge of the capacitor C is completed. However, the present invention is not limited to this. May be.

  Here, in FIG. 12, the discharge state of the capacitor C when the conventional photo MOSFET is used as the switching element of the discharge path is indicated by an imaginary line. Since the rated current of the photo MOSFET is lower than that of the first and second non-insulated elements M1 and M2, it takes time to discharge, and as shown by an imaginary line in FIG. It takes time a7, and as a result, it takes time Tx to complete a series of voltage detection processes.

  On the other hand, in the power supply monitoring device 23 according to the present embodiment, the discharge time can be shortened by providing the first and second non-insulated elements M1 and M2 (MOSFETs) in the discharge path P10. A series of voltage detection processes can be completed at time Ta. Therefore, in the present embodiment, the time for the voltage detection process can be shortened by the time Tb that is the difference between the time Tx and the time Ta.

  In addition, since the shortening of the voltage processing time described above is caused by the shortening of the discharging time, the processing time for detecting the deterioration of the insulation resistances Rp and Rn for discharging the capacitor C is similarly shortened. be able to.

  Returning to the description of FIG. 11, the control unit 26 then forms the third path P3 and charges the capacitor C with the second stack voltage (step S13). Next, the control unit 26 forms the second path P2 to detect the second stack voltage (step S14), and subsequently forms the discharge paths P10, P11, and P12 to complete the discharge of the capacitor C (step S14). S15).

  Next, the control unit 26 forms the fourth path P4 (step S16), and after a predetermined time elapses, forms the second path P2 and detects the voltage VRp of the capacitor C (step S17). Next, the control unit 26 forms the discharge paths P10, P11, P12, and completes the discharge of the capacitor C (step S18).

  Next, the control unit 26 forms the fifth path P5 (step S19), and after a predetermined time elapses, forms the second path P2 and detects the voltage VRn of the capacitor C (step S20). Subsequently, the control unit 26 forms the discharge paths P10, P11, and P12, and completes the discharge of the capacitor C (step S21).

  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 S17 and S20 (step S22). 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 S23).

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

  As described above, the power monitoring device 23 according to the embodiment includes the capacitor C, the first and second non-insulating elements M1 and M2, and the insulating element SW. The capacitor C is charged by the assembled battery 10 (an example of a power source) and is used at least for monitoring the voltage of the assembled battery 10. The first and second non-insulated elements M1 and M2 are provided in a discharge path P10 that discharges the charged capacitor C. The insulating element SW is connected to the gate terminals of the first and second non-insulating elements M1 and M2. Thereby, in the power supply monitoring apparatus 23, the time which a voltage detection process requires can be shortened.

  In addition, in the discharge path P10 according to the present embodiment, the first and second non-insulated elements M1 and M2 having a relatively high rated current are provided, so that, for example, a discharge resistor for reducing the current is unnecessary. Therefore, the circuit configuration can be simplified.

  Further, for example, even when the battery stack 12 or the battery cell 13 is increased due to a change in vehicle specifications, in the present embodiment, the time for the voltage detection process is shortened, and therefore within the specified detection time. Thus, it is possible to detect the voltage of the increased battery stack 12. In other words, the power supply monitoring device 23 according to the present embodiment can easily cope with the increase in the battery stack 12 and the battery cells 13.

  In the above-described embodiment, the positions and the number of the first and second non-insulating elements M1 and M2, the insulating element SW, the capacitor C, etc. are examples and are not limited.

  Further, in the above-described deterioration detection of the insulation resistances Rp and Rn, the voltage VRp and the voltage VRn of the capacitor C are respectively compared with the predetermined 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 26 Control part C Capacitor M1 1st non-insulation type element M2 2nd non-insulation type element P10, P11 , P12 Discharge path Rn Insulation resistance Rp Insulation resistance SW Insulation type element

Claims (4)

A capacitor charged by a power source and used at least for monitoring the voltage of the power source;
A non-insulating switching element provided in a discharge path for discharging the charged capacitor;
An insulating switching element connected to a gate terminal of the non-insulating switching element. The non-insulating switching element is
The power supply monitoring apparatus according to claim 1, wherein the discharge path is formed by driving and driving the charged voltage of the capacitor through the insulating switching element. There are two non-insulating switching elements,
The two non-insulating switching elements are:
The power supply monitoring device according to claim 1, wherein the power supply monitoring device is connected in series so as to be conductive in both directions. The insulating switching element further includes:
The power supply monitoring apparatus according to claim 3, wherein the power supply monitoring apparatus is connected between the two non-insulated switching elements connected in series.

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