JP5226502B2 - Current sensor ground fault judgment device and method - Google Patents

Description

  The present invention relates to a ground fault determination device for a current sensor that determines whether or not a current sensor of a DC / DC converter connected between a first power device and a second power device has a ground fault, and a method thereof.

  A battery is a first power device, a fuel cell is a second power device, a DC / DC converter is connected between the first power device and the second power device, and the voltage of the battery is converted by the DC / DC converter. A hybrid fuel cell system has been proposed in which a motor is driven through an inverter by using a current that is boosted and flows from the battery and a combined current that flows from the fuel cell (Patent Document 1).

  In the hybrid fuel cell system according to Patent Document 1, a sensor (current sensor) that detects a current value (control current value) to control the amount of current flowing out of the battery includes a primary side of the DC / DC converter and It is inserted on the secondary side.

JP 2007-159315 A

  In the hybrid fuel cell system as described above, when the current sensor has a ground fault, the current waveform sensed becomes an oscillation waveform, and the ground fault of the current sensor may not be detected. Note that Patent Document 1 does not disclose a ground fault of the current sensor.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a ground fault determination device and method for a current sensor that can reliably detect an abnormality due to a ground fault of the current sensor. And

  A ground fault determination device for a current sensor according to the present invention is configured to determine whether a current sensor of a DC / DC converter connected between a first power device and a second power device has a ground fault. In the determination device, whether or not the current detection value by the current sensor is abnormal is determined in a first determination cycle, and when it is determined to be abnormal, an abnormality determination processing unit that turns on an abnormality detection flag, and the abnormality detection flag An abnormality confirmation processing unit that turns on an abnormality confirmation flag when it is determined that the signal is on, and determines that the second determination period is on. The period is longer than one determination period.

  Moreover, the ground fault determination method of the current sensor according to the present invention includes a current sensor for determining whether a current sensor of a DC / DC converter connected between the first power device and the second power device has a ground fault. In the ground fault determination method, an abnormality determination process for determining whether or not a current detection value by the current sensor is abnormal in a first determination cycle and turning on an abnormality detection flag when it is determined as abnormal, and the abnormality detection Whether or not the flag is turned on is determined in a second determination cycle that is longer than the first determination cycle, and when it is determined that the flag is turned on, an abnormality confirmation processing step for turning on the abnormality confirmation flag; It is characterized by having.

  Further, it is preferable to prohibit the control using the current sensor when the abnormality confirmation flag is turned on.

  Furthermore, the present invention is preferably applied to a fuel cell system in which the first power device is a power storage device and the second power device is a fuel cell.

  Furthermore, the present invention is preferably applied to a fuel cell vehicle in which the first power device is a power storage device, and the second power device is a fuel cell and a motor connected in parallel to the fuel cell and generating regenerative power. It is.

  According to this invention, it is determined whether or not the current detection value by the current sensor is abnormal, and when it is determined to be abnormal, the abnormality determination process for turning on the abnormality detection flag is longer than the first determination cycle. 2 It is determined whether or not the abnormality detection flag is turned on in the determination cycle. When it is determined that the abnormality detection flag is turned on, abnormality confirmation processing for turning on the abnormality confirmation flag is performed. Even if the current detection value intermittently enters the normal range during the second determination cycle due to increase or decrease in current, the current determination value is abnormal due to the abnormality determination process in the first determination cycle even once during the second determination cycle. When it is determined that it is present (detected as abnormal), a ground fault can be determined.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle or the like to which a DC / DC converter device that performs a ground fault determination method for a current sensor according to the present invention is applied will be described with reference to the drawings.

A. Explanation of overall configuration [Overall configuration]
FIG. 1 shows a schematic overall configuration diagram of a fuel cell vehicle 10 in which a ground fault determination device for a current sensor according to this embodiment is incorporated.

  The fuel cell vehicle 10 basically includes a battery 12 as a first DC power supply (first power device) that generates a primary voltage V1 on the primary side 1S and a secondary voltage V2 on the secondary side 2S. A hybrid DC power supply (hybrid power system) composed of a fuel cell (Fuel Cell) 14 as a generated second DC power supply (second power supply), and a load supplied with power from the hybrid DC power supply And a traveling motor 16.

[Fuel cell and its system]
The fuel cell 14 has, for example, a stack structure in which cells formed by sandwiching a solid polymer electrolyte membrane between an anode electrode and a cathode electrode from both sides are stacked. A reaction gas supply unit 18 is connected to the fuel cell 14 through a pipe. The reactive gas supply unit 18 includes a hydrogen tank that stores hydrogen (fuel gas) that is one reactive gas, and a compressor that compresses air (oxidant gas) that is the other reactive gas. The generated current generated by the electrochemical reaction in the fuel cell 14 of hydrogen and air supplied from the reaction gas supply unit 18 to the fuel cell 14 is supplied to the motor 16 and the battery 12 via the diode 13.

  The fuel cell system 11 includes a fuel cell 14 and a reaction gas supply unit 18 and a fuel cell control unit (FC control unit) 44 that controls them.

[DC / DC converter]
The DC / DC converter 20 is connected to a battery 12 having one side connected to the primary side 1S, and the other side is connected to a secondary side 2S, which is a connection point between the fuel cell 14 and the motor 16, and a chopper type voltage conversion. Device.

  The DC / DC converter 20 performs voltage conversion (step-up conversion) from the primary voltage V1 to the secondary voltage V2 (V1 ≦ V2), and step-up / step-down conversion that converts the secondary voltage V2 into the primary voltage V1 (step-down conversion). This is a chopper type voltage converter.

[Inverter, motor and drive system]
The inverter 22 has a three-phase full-bridge configuration, performs DC / AC conversion, converts DC to three-phase AC, and supplies it to the motor 16, while DC after AC / DC conversion accompanying the regenerative operation. Is supplied from the secondary side 2S to the primary side 1S through the DC / DC converter 20, and the battery 12 is charged.

  The motor 16 rotates the wheels 26 through the transmission 24. In practice, the inverter 22 and the motor 16 are collectively referred to as a load 23.

[High voltage battery]
A high voltage battery 12 connected to the primary side 1S is a power storage device (energy storage), and for example, a lithium ion secondary battery or a capacitor can be used. In this embodiment, a lithium ion secondary battery is used.

[Various sensors, main switches and communication lines]
A main switch (power switch) 34 and various sensors 36 are connected to the overall control unit 40. The main switch 34 has a function as an ignition switch that turns on (starts or starts) and turns off (stops) the fuel cell vehicle 10 and the fuel cell system 11. Various sensors 36 detect state information, such as a vehicle state and an environmental state. As the communication line 38, a CAN (Controller Area Network) that is an in-vehicle LAN is used.

[Control unit]
The overall control unit 40, the FC control unit 44, the motor control unit 46, the converter control unit 48, and the battery control unit 52 are connected to the communication line 38. A DC / DC converter device 50 is formed by the DC / DC converter 20 and the converter control unit 48 that controls the DC / DC converter 20.

  Each control unit 40, 44, 46, 48, 52 includes a microcomputer, detects state information of various switches such as the main switch 34 and various sensors 36, and also controls each of the control units 40, 44, 46, 48, 52. Each CPU implements various functions by inputting status information from these switches and sensors and information (commands, etc.) from other controllers, and executing programs stored in memory (ROM). It operates as a function realization unit (function realization means). The control units 40, 44, 46, 48, and 52 have an input / output interface such as a timer, an A / D converter, and a D / A converter, as necessary, in addition to a CPU and a memory.

B. Detailed configuration description [DC / DC converter device]
FIG. 2 shows a detailed configuration of the DC / DC converter 20. The DC / DC converter 20 includes three-phase phase arms UA, VA, WA arranged between the primary side 1S and the secondary side 2S, and a reactor 90.

  The U-phase arm UA includes an upper arm element (upper arm switching element 81u and diode 83u) and a lower arm element (lower arm switching element 82u and diode 84u).

  V-phase arm VA includes an upper arm element (upper arm switching element 81v and diode 83v) and a lower arm element (lower arm switching element 82v and diode 84v).

  W-phase arm WA includes an upper arm element (upper arm switching element 81w and diode 83w) and a lower arm element (lower arm switching element 82w and diode 84w).

  As the upper arm switching elements 81u, 81v, 81w and the lower arm switching elements 82u, 82v, 82w, for example, MOSFETs or IGBTs are employed.

  Reactor 90 is inserted between the midpoint (common connection point) of each phase arm UA, VA, WA and the positive electrode of battery 12, and is connected between primary voltage V1 and secondary voltage V2 by DC / DC converter 20. When the voltage is converted at, energy is released and stored.

  The upper arm switching elements 81u, 81v, 81w are turned on by the high level of the gate drive signals (drive voltages) UH, VH, WH output from the converter control unit 48, and the lower arm switching elements 82u, 82v, 82w are The gate drive signals (drive voltages) UL, VL, WL are turned on by the high level. The converter control unit 48 detects the primary voltage V1 by the voltage sensor 91 provided in parallel with the primary side smoothing capacitor 94, detects the primary current I1 by the current sensor 101, and detects the secondary side smoothing capacitor 96. The secondary voltage V2 is detected by a voltage sensor 92 provided in parallel with the current sensor 102, and the secondary current I2 is detected by a current sensor 102.

[Operation of DC / DC converter device]
The time chart of FIG. 3 is an explanatory diagram of the three-phase arm replacement drive operation of the DC / DC converter device 50.

  In the step-down chopper control related to the step-down operation (regeneration operation), the secondary current I2 flowing out from the load 23 and the fuel cell 14 passes through the DC / DC converter 20 and charges the battery 12 as the primary current I1. In the step-up chopper control related to the step-up operation (power running operation), the primary current I1 flowing out from the battery 12 passes through the DC / DC converter 20 and drives the load 23 including the motor 16 as the secondary current I2.

Assuming that the switching period is 2π = T and the period during which a high-level drive signal is transmitted to the upper and lower arm switching elements 81 and 82 is Ton, the driving duty (ON duty) in the step-down chopper control is ignored if the dead time dt is ignored. ) Is expressed by equation (1), and the drive duty in boost chopper control is expressed by equation (2).
Ton / T = V1 / V2 (1)
Ton / T = (1−V1 / V2) (2)

  The drive signals UH, UL, VH, VL, WH, and WL are supplied with the drive signals UH, UL, VH, VL, WH, and WL during the period Ton indicated as “ON” with hatching. This is a period during which the arm switching element (for example, the arm switching element corresponding to the drive signal UH is the upper arm switching element 81u) is flowing (current is flowing). During the period (“period” is equal to Ton) where “ON” is displayed without hatching, the arm switching element to which the drive signals UH, UL, VH, VL, WH, WL are supplied (for example, the drive signal UL) The arm switching element corresponding to is a period in which the lower arm switching element 82u) is not flowing (no current is flowing).

  In any operation of the step-down chopper control and step-up chopper control of the DC / DC converter 20, the upper arm switching element 81 (81u to 81w) and the lower arm switching element 82 (82u) of the same phase every switching cycle 2π. To 82w), high level drive signals UH, UL, VH, VL, WH, WL are output. In addition, the drive signals UH, UL, VH, VL, WH, and WL are output by changing (rotating) the UVW phase. In the step-down chopper control, the upper arm switching elements 81 (81u to 81w) are passed by the drive signals UH, VH, and WH. In the step-up chopper control, the lower arm switching elements 82 (82u to 82w are driven by the drive signals UL, VL, and WL. ).

  In this case, in order to prevent the secondary voltage V2 from being short-circuited simultaneously between the upper and lower arm switching elements 81 and 82, each drive signal UH, UL, VH, VL, WH, WL is set to the dead time dt. A high level “ON” is set across the screen. That is, so-called synchronous switching is performed with the dead time dt interposed therebetween.

  In the step-down chopper control, first, the secondary current I2 flows as the primary current I1 to the reactor 90 through the upper arm switching element 81u during a period in which only the upper arm switching element 81u (U phase) is passed by the drive signal UH. The energy is accumulated in the reactor 90 and the battery 12 is charged.

  Next, during a period in which only the drive signal UL is at a high level, the lower arm switching element 82u does not flow, and the diodes 84u, 84v, 84w are turned on to release the energy accumulated in the reactor 90. The battery 12 is charged. Hereinafter, similarly, the V phase and the W phase are repeated.

  In the step-up chopper control, first, energy is accumulated in the reactor 90 by the primary current I1 from the battery 12 during a period in which only the drive signal UL (U phase) is at a high level (a period indicated by hatching). At this time, a current is supplied from the secondary side smoothing capacitor 96 to the load 23.

  Next, during a period in which only the drive signal VH (V phase) is at a high level, the upper arm switching element 81v does not flow, and the diodes 83u, 83v, 83w are conducted and accumulated in the reactor 90. The energy is released, the primary current I1 from the reactor 90 passes through the DC / DC converter 20, charges the secondary-side smoothing capacitor 96 as the secondary current I2, and is supplied to the load 23. Hereinafter, the V phase and the W phase are similarly repeated.

  Thus, in the three-phase arm replacement drive operation, the U-phase arm UA, the V-phase arm VA, and the W-phase arm WA are switched and switched.

C. Description of Operation Next, the operation of the DC / DC converter device 50 that performs the ground fault determination method of the current sensor according to this embodiment, in this embodiment the current sensor 101 inserted in the primary side 1S, will be described with reference to the converter of FIG. This will be described with reference to the functional block diagram of the control unit 48, the flowcharts of FIGS. 5 to 7, and the time charts of FIGS.

  10 and 11 are time charts of comparative examples to which the ground fault determination method of the current sensor 101 according to this embodiment is not applied.

  As shown in FIG. 4, the converter control unit 48 detects an A / D converter 72 that converts a primary current I1 detected by the current sensor 101 into a primary current I1ad of a digital signal, and a voltage sensor 91. An A / D converter 71 that converts the primary voltage V1 into the primary voltage V1ad of the digital signal, and an A / D converter that converts the secondary voltage V2 detected by the voltage sensor 92 into the secondary voltage V2ad of the digital signal. 70 and a primary current abnormality determination / control value calculation processing unit (including a primary current abnormality determination processing unit and a primary current control value calculation processing unit, which are described as I1 abnormality determination / control value calculation processing unit in FIG. 74 and a primary current abnormality timer 75 (also referred to as a primary current abnormality timer unit, also referred to as I1 abnormality timer 75 in FIG. 4). 4, I1 abnormality confirmation processing part Provided that indicated.) 76, a control mode determination unit 78 for determining the operation control mode of the DC / DC converter 20, a drive duty calculation unit 80, and a gate drive circuit 85. Here, the primary current abnormality timer 75 is a subtraction timer (subtraction counter).

  The ground fault of the current sensor 101 means that the detection line of the current sensor 101 operating at the high voltage reference ground is short-circuited to the chassis ground of the fuel cell vehicle 10.

  In this embodiment, the primary current abnormality determination / control value calculation processing unit 74 and the primary current abnormality confirmation processing unit 76 including the primary current abnormality timer 75 constitute a ground fault determination device 77 of the current sensor 101. .

  In the ground fault determination device 77, one primary current abnormality determination / control value calculation processing unit 74 turns on (also referred to as ON or set) the primary current abnormality detection flag Fab according to the flowchart of FIG. 6 as described later. ) And a calculation process of the primary current control value I1c.

  The primary current I1 is either a charging current to the battery 12 or a discharging current from the battery 12. However, if any current flows over a certain threshold current Ith, the battery 12 deteriorates, so the primary current I1. It is not preferable to flow more than the threshold current Ith.

  In practice, the value of the threshold current Ith related to deterioration differs between the discharge current and the charging current. However, in this embodiment, the threshold current Ith related to the deterioration of the discharge current and the charging current is set to the same value for easy understanding. Will be described.

  As will be described later, the primary current abnormality determination / control value calculation processing unit 74 follows the flowchart of FIG. 6 and the primary current I1ad is outside the predetermined AD value normal range In (see FIG. 8). Is determined, that is, when the primary current I1ad is equal to or less than the AD lower limit value Ip or the AD upper limit value Iq, the current sensor 101 is determined to be abnormal and the abnormality detection flag Fab is turned on. When I1ad is a value within the predetermined AD value normal range In (Ip <I1ad <Iq), so-called normal determination is not performed and the abnormality detection flag Fab is left as it is.

  In the ground fault determination device 77, the other primary current abnormality confirmation processing unit 76, as will be described later, in accordance with the flowchart of FIG. 7, the primary current abnormality of the primary current abnormality timer value (primary current abnormality count value) Tab. Preset processing to the timer 75 (in this embodiment, Tab = Tpreset = 3) and subtraction processing (Tab ← Tab−1), processing for turning on the primary current abnormality determination flag Fd, and primary current abnormality detection flag Fab And the like to turn off (also referred to as OFF or reset).

  Based on the primary current control value Ic1 from the primary current abnormality determination / control value calculation processing unit 74, the primary current abnormality determination flag Fd from the primary current abnormality determination processing unit 76, etc. The operation mode of the DC converter 20 is determined as the secondary voltage control mode (V2 control mode) or the primary current limit mode (I1 limit mode).

  The drive duty calculation unit 80 calculates the drive duty based on the secondary voltage command value V2com, the secondary voltage V2ad, and the primary voltage V1ad based on the notification of the operation mode notified from the control mode determination unit 78, or the primary A drive duty is calculated based on the current control value Ith and set in the gate drive circuit 85. The gate drive circuit 85 includes a timer and outputs drive signals UH, VH, WH, UL, UV, UW corresponding to the drive duty set for the upper and lower arm switching elements 81u, 81v, 81w, 82u, 82v, 82w. The upper and lower arm switching elements 81u, 81v, 81w, 82u, 82v and 82w are supplied.

  In step S <b> 1 of FIG. 5, converter control unit 48 receives secondary voltage command value V <b> 2 com sent from overall control unit 40.

  Here, the overall control unit 40 determines the fuel determined based on the input (load request) from various sensors 36 in addition to the state of the fuel cell 14, the state of the battery 12, the state of the motor 16, and the state of the auxiliary machine (not shown). From the total load request amount of the battery vehicle 10, the fuel cell shared load amount (request output) that the fuel cell 14 should bear, the battery share load amount (request output) that the battery 12 should bear, and the regenerative power source should bear The distribution (sharing) of the regenerative power distribution load amount is determined while arbitrating, and a command is sent to the FC control unit 44, the motor control unit 46, and the converter control unit 48.

  Next, in step S <b> 2, the primary current I <b> 1 is detected by the current sensor 101, converted to the primary current I <b> 1 </ b> ad by the A / D converter 72, and supplied to the primary current abnormality determination / control value calculation processing unit 74.

  Next, the primary current abnormality determination / control value calculation processing unit 74 performs the primary current abnormality determination / control value calculation processing in step S3 for each first determination cycle T1 (see FIG. 8). In the primary current abnormality determination / primary current control value calculation processing in step S3, as shown in FIG. 6, it is determined whether or not the abnormality confirmation flag Fd is turned off in step S3a (Fd = OFF?). .

  If the abnormality confirmation flag Fd is not turned off, the abnormality confirmation flag Fd is on (Fd = ON). In this case, in step S3e, the current sensor 101 is grounded. The primary current control value I1c is set to zero (I1c = 0).

  On the other hand, when the abnormality confirmation flag Fd is off, when it is determined in step S3b that the primary current I1ad is outside the predetermined AD value normal range In (see FIG. 8), that is, When the primary current I1ad is not more than the AD lower limit value Ip or not less than the AD upper limit value Iq, in step S3c, the current sensor 101 is determined to be abnormal (estimated), and the abnormality detection flag Fab is turned on (Fab = ON).

  If the determination in step S3b is negative, a primary current control value I1c is calculated in step S3d.

  Next, the primary current abnormality confirmation process of step S4 is performed for every 2nd determination period T2 (refer FIG. 8).

  In the primary current abnormality confirmation process in step S4, as shown in FIG. 7, it is determined whether or not the abnormality confirmation flag Fd is turned on in step S4a (Fd ≠ ON?) And is not turned on. In this case, in step S4b, it is determined whether or not the abnormality detection flag Fab is turned on (Fab = ON?).

  If the abnormality detection flag Fab is not turned on in step S4b (Fab = OFF), the primary current abnormality timer value Tab is preset in the primary current abnormality timer 75 in step S4c (Tab = Tpreset). = 3).

  If the abnormality detection flag Fab is turned on in step S4b (Fab = ON), the primary current abnormality timer value Tab is subtracted by 1 in step S4e (Tab ← Tab-1).

  In step S4f, the abnormality detection flag Fab that is turned on is turned off (Fab = OFF).

  Next, in step S5 of FIG. 5, the control mode determination unit 78 determines whether or not the abnormality confirmation flag Fd is on (Fd = ON?).

  If the abnormality confirmation flag Fd is on, it is determined that the current sensor 101 is abnormal, so that the current mode control using the current sensor 101 is not performed and the control mode determination unit 78 is performed in step S7. Determines to perform processing in the secondary voltage control mode (V2 control mode) and notifies the drive duty calculation unit 80 of the determination.

  On the other hand, in step S5, the control mode determination unit 78 estimates that the current sensor I1 is normal when the abnormality determination flag Fd is not on.

  In step S6, the primary current abnormality determination / control value calculation processing unit 74 determines whether or not the absolute value of the primary current I1ad is greater than or equal to the threshold current Ith (| I1ad |> Ith?), And | I1ad |> If it is Ith, the control mode determination unit 78 notifies the drive duty calculation unit 80 to perform processing in the primary current limit mode (I1 limit mode) using the current sensor 101 in step S8.

  If it is determined in step S6 that | I1ad | ≦ Ith, processing in the primary voltage limiting mode using the current sensor 101 is not performed, and in step S7, in the secondary voltage control mode. The process is determined to be performed, and the drive duty calculation unit 80 is notified.

  As described above, the ground fault determination device 77 of the current sensor 101 according to the above-described embodiment is driven by the fuel cell 14 as the first power device and the battery 12 (or the battery 12 and the inverter 22 as the second power device). When the current sensor 101 of the DC / DC converter 20 connected to the regenerative electric power from the motor 24 is grounded, it is determined whether or not the current detection value I1ad by the current sensor 101 is abnormal. The primary current abnormality determination / control value calculation processing unit 74 as an abnormality determination processing unit that turns on the abnormality detection flag Fab when it is determined that the abnormality is detected in the first determination cycle T1, and the abnormality detection flag Fab. Is determined in the second determination cycle T2, and when determined to be on, an abnormality confirmation processing unit that turns on the abnormality confirmation flag Fd A primary current abnormality determination processing section 76 of Te, with a, and the second determination period T2 to the long period than the first determination cycle T1.

  In this way, it is determined whether or not the current detection value I1ad by the current sensor 101 is abnormal, and the first abnormality determination process (step S3) is performed to turn on the abnormality detection flag Fab when it is determined to be abnormal. In addition to the determination cycle T1, it is determined whether or not the abnormality detection flag Fab is turned on at a second determination cycle T2 having a predetermined cycle longer than the first determination cycle T1, and when it is determined that the abnormality detection flag is turned on, an abnormality confirmation flag Since the abnormality confirmation process (step S4) for turning on Fd is performed, the current detection value I1ad may intermittently enter the normal range during the second determination cycle T2 due to the increase or decrease of the oscillation current at the time of the ground fault. Even if it is determined to be abnormal (detected as abnormal) by the abnormality determination process of the first determination period T1 even once during the second determination period T2, a ground fault can be determined.

  That is, in the primary current abnormality determination / control value calculation process (step S3), normality is determined without determining normality, and in the primary current abnormality confirmation process (step S4), normality determination process for turning off the abnormality detection flag Fab. Is also included.

  Further, when the abnormality confirmation flag Fd is turned on, the control using the current sensor 101 is prohibited, so that the occurrence of unstable control can be suppressed in advance.

  When the time chart of FIG. 8 according to the embodiment is described in a confirming manner, the primary current I1ad is outside the AD value normal range In between the time point ta and the time point tb, and the primary current abnormality confirmation process substantially coincides with the time point tb. The abnormality detection flag Fab is turned off (S4f) at time t1 when (steps S4b, S4d: YES, S4d: YES, S4e, S4f) is performed, and the primary current abnormality timer value Tab of the primary current abnormality timer 75 is The value 3 is changed to the value 2 (S4e). Between the time points td and te, the primary current I1ad is within the AD value normal range In, but the abnormality detection flag Fab is not turned off. At time tg (approximately time t2), the primary current abnormality determination process in step S4 is executed again, and the primary current abnormality timer value Tab of the primary current abnormality timer 75 is changed from the value 2 to the value 1 (S4e). . At time t4, the determination in step S4d (Tab> 0) is negative, and the abnormality determination flag Fd is turned on (see also the time reduction time chart of FIG. 9).

  In contrast, when the time chart of FIG. 10 according to the comparative example is described in a confirming manner, an abnormality / normality determination process is performed for each first determination period T1. Therefore, for example, when the primary current I1ad is outside the AD value normal range In in the determination period from ta to tb, the abnormality detection flag Fab is turned on, and in the determination period td to te, the primary current Iad is If it is within the AD value normal range In, the abnormality detection flag Fab is turned off. When processing is performed in this manner, the abnormality of the current sensor 101 cannot be determined even by the abnormality determination process performed in the second determination cycle T2 (see also the time reduction time chart of FIG. 11).

  When the current sensor 101 has a ground fault, the waveform of the primary current I1 becomes an abnormal oscillation waveform, and the primary current I1ad that is the AD value takes a value within or outside the AD value normal range In (FIG. 8). The primary current I1ad having the same waveform in FIG. 10).

  The present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the description of this specification.

1 is a schematic overall configuration diagram of a fuel cell vehicle in which a ground fault determination device according to an embodiment of the present invention is incorporated. It is a circuit diagram which shows the detailed structure of a DC / DC converter. It is a time chart used for description of a three-phase arm replacement drive operation. It is a functional block diagram of the converter control part in which the ground fault determination apparatus which concerns on one Embodiment of this invention was integrated. It is a flowchart provided to the whole operation | movement description of a ground fault determination process. It is a flowchart with which description of a primary current abnormality determination and control value calculation process is provided. It is a flowchart provided for description of a primary current abnormality confirmation process. It is a time chart used for description of the ground fault determination process which concerns on this embodiment. FIG. 9 is a time axis reduction time chart of the example time chart of FIG. 8. FIG. It is a time chart used for description of the ground fault determination process which concerns on a comparative example. It is a time-axis reduction | decrease time chart of the time chart of the example of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell vehicle 11 ... Fuel cell system 12 ... Battery 14 ... Fuel cell 16 ... Motor 20 ... DC / DC converter 48 ... Converter control part 50 ... DC / DC converter device 74 ... Primary current abnormality determination and control value calculation process Unit 75 ... Primary current abnormality timer 76 ... Primary current abnormality determination processing unit 77 ... Ground fault determination device

Claims (5)

In a ground fault determination device for a current sensor that determines whether or not a current sensor of a DC / DC converter connected between a first power device and a second power device has a ground fault based on a current detection value of an oscillation waveform .
Together with the current detection value by the current sensor, whether the abnormal, judged by the first judging period of the long period than the oscillation period of the oscillating waveform to turn on the abnormality detection flag when it is determined that abnormality, An abnormality determination processing unit that does not turn off the abnormality detection flag when it is determined that there is no abnormality ;
Whether or not the abnormality detection flag is turned on is determined in a second determination cycle longer than the first determination cycle, and when it is determined that the abnormality detection flag is turned on, an abnormality confirmation flag is set. An abnormality confirmation processing section to be turned on;
Ground fault determination apparatus of the current sensor, characterized in that Ru comprising a. In the ground fault judgment apparatus of the current sensor according to claim 1,
When the abnormality confirmation flag is turned on, control using the current sensor is prohibited. In the ground fault determination apparatus of the current sensor according to claim 1 or 2 ,
The abnormality confirmation processing unit
When turning on the abnormality confirmation flag,
Whether or not the abnormality detection flag is turned on is determined in a second determination cycle longer than the first determination cycle, and when it is determined that the abnormality detection flag is turned on, the abnormality detection flag is turned off. And when determining that the abnormality detection flag is continuously turned on a plurality of times in the determination at each second determination cycle, the abnormality confirmation flag is turned on.
A ground fault determination device for a current sensor. The first power device according to any one of claims 1 to 3 comprises a power storage device, and the second power device includes a fuel cell and a motor connected in parallel to the fuel cell and generating regenerative power. A fuel cell vehicle. In the ground fault determination method of the current sensor for determining whether the current sensor of the DC / DC converter connected between the first power device and the second power device has a ground fault, based on the current detection value of the oscillation waveform ,
Whether the current detection value by the current sensor is abnormal, together with the than the oscillation period of the oscillation waveform is determined by the first determination period of the long period, to turn on the abnormality detection flag when it is determined that abnormality, abnormality An abnormality determination process that does not turn off the abnormality detection flag when it is determined that
Whether or not the abnormality detection flag is turned on is determined in a second determination cycle longer than the first determination cycle, and when it is determined that the abnormality detection flag is turned on, an abnormality confirmation flag is set. Anomaly confirmation process to turn on,
A ground fault determination method for a current sensor, comprising:

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