JP2010161898A - Dc/dc converter system and control method to carry out upon failure detection in system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC/DC converter system which controls a DC/DC converter more properly even when a primary voltage drops abnormally. <P>SOLUTION: When a primary voltage V1 drops abnormally, whether the voltage drop is caused by a failure of a connector 15 that connects a battery 12 to a DC/DC converter 20 or by a failure of a primary sensor 91 that detects the primary voltage V1 is determined, and the DC/DC converter 20 is controlled depending on the result of the determination. This enables more proper control of the DC/DC converter 20. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a DC / DC converter system in which a first power device is connected to a primary side of a DC / DC converter through a connector, and a secondary side of the DC / DC converter is connected to a second power device, and the system The present invention relates to an abnormality detection control method.

  Conventionally, a hybrid power supply vehicle has been proposed in which an electric motor for driving a vehicle is driven by using a battery and a fuel cell in combination (Patent Document 1).

  In the hybrid power supply vehicle described in Patent Document 1, the fuel cell is connected to the electric motor via an inverter, and the battery is connected to the fuel cell via a DC / DC converter that functions as a bidirectional voltage converter. Connected.

  Further, the hybrid power supply vehicle is configured such that the voltage on the secondary side of the DC / DC converter, that is, the voltage of the fuel cell (inter-terminal voltage) is controlled.

  Furthermore, in a hybrid power supply vehicle as shown in Patent Document 1, power is normally supplied from the battery that generates a primary voltage to auxiliary devices such as a light, a power window, and a wiper motor.

  During the regenerative operation of the electric motor, the auxiliary machine is driven from the inverter via the DC / DC converter by the electric power having the voltage generated on the secondary side, and the battery is charged.

JP 2007-159315 A

  By the way, in the hybrid power supply vehicle in which the auxiliary machine is connected to the battery and the battery is connected to the fuel cell and the inverter-driven electric motor via the DC / DC converter, The secondary voltage (primary voltage) may drop abnormally.

  There is no description in Patent Document 1 regarding the problem with respect to the abnormal drop of the primary voltage.

  The present invention has been made in consideration of such a problem, and is a DC / DC converter system capable of more appropriately controlling a DC / DC converter even when the primary voltage is abnormally reduced. And it aims at providing the control method at the time of abnormality detection in this system.

  A DC / DC converter system according to the present invention is connected to a primary side of a DC / DC converter from a first power device through a connector, and a secondary side of the DC / DC converter is connected to a second power device. In the DC converter system, a primary voltage sensor connected to the primary side for detecting a primary voltage, a secondary voltage sensor connected to the secondary side for detecting a secondary voltage, and the primary voltage sensor. When the primary voltage detection value detected by the voltage drops below a lower limit threshold for determining an abnormality, it is determined whether the connector is abnormal or an abnormality of the primary voltage sensor that detects the primary voltage detection value. And a control unit that controls the DC / DC converter according to the determination result.

  In the control method for abnormality detection in the DC / DC converter system according to the present invention, the first power device is connected to the primary side of the DC / DC converter through the connector, and the secondary side of the DC / DC converter is the second power device. In the control method at the time of abnormality detection in the DC / DC converter system connected to the base, a process of detecting the primary voltage that is the primary side voltage, and a process of detecting the secondary voltage that is the secondary side voltage; Determining when the primary voltage detection value falls below a lower limit threshold value for determining abnormality, determining whether the connector is abnormal or voltage detection abnormality, and controlling the DC / DC converter according to the determination result; It is characterized by having.

  A battery can be applied as the first power device, and a fuel cell can be applied as the second power device.

  According to the present invention, when the voltage on the primary side (primary voltage) is abnormally lowered, it is determined whether the connector connecting the first power device and the DC / DC converter is abnormal or the voltage detection is abnormal. Since the DC / DC converter is controlled according to the determination result, the DC / DC converter can be controlled more appropriately.

1 is a schematic overall configuration diagram of a fuel cell vehicle according to an embodiment of the present invention. It is a circuit diagram which shows the detailed structure of the DC / DC converter which concerns on this embodiment. It is a time chart used for description of a three-phase arm replacement drive operation. It is a block diagram of the DC / DC converter system which implements the control method at the time of abnormality detection which concerns on this embodiment. It is a functional block diagram of a secondary voltage control part. It is a functional block diagram of a primary voltage control part. It is a flowchart which concerns on a primary voltage abnormality detection process. It is a flowchart which concerns on a gate interruption | blocking judgment process. It is a flowchart which concerns on a control command determination process. It is a flowchart which concerns on the open fault determination process of a connector, and the detection abnormality determination process of a primary voltage sensor. It is a time chart which concerns on the detection process at the time of primary voltage abnormality generation | occurrence | production. It is a time chart which concerns on the detection process at the time of the open failure generation | occurrence | production of a connector.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle or the like that implements a control method for abnormality detection in a DC / DC converter system according to the present invention 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 according to this embodiment.

  The fuel cell vehicle 10 basically includes a battery 12 as a first DC power supply device that generates a primary voltage V1 on the primary side 1S and a second DC power supply that generates a secondary voltage V2 on the secondary side 2S. A hybrid DC power supply device including a fuel cell 14 as a device, and a traveling motor 16 that is a load supplied with power from the hybrid DC power supply device.

[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. A power generation current generated by an 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 25.

  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 converts the primary voltage V1 into a secondary voltage V2 (V1 ≦ V2) (boost conversion), and also converts the secondary voltage V2 into a primary voltage V1 (step-down conversion). This is a voltage conversion device.

[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 primary voltage sensor 91 provided in parallel with the primary side smoothing capacitor 94, detects the primary current I1 by the current sensor 101, and smoothes the secondary side smoothing. Secondary voltage V2 is detected by secondary voltage sensor 92 provided in parallel with capacitor 96, and secondary current I2 is detected by current sensor 102.

  Here, a fuse 13 is connected in series to the battery 12, and a connector 15 is connected between the battery 12 and the primary side 1S. An auxiliary machine (AUX) 17 is connected to the primary side 1S. The auxiliary machine 17 is a light, a power window, a wiper electric motor, or the like.

[Operation of DC / DC converter device]
In this embodiment, the DC / DC converter device 50 operates in a three-phase arm alternating drive operation.

(3-phase arm replacement drive operation: also referred to as 3-phase replacement drive or 3-phase operation)
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 of the drive signals UH, UL, VH, VL, WH, WL has a 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.

  In this three-phase arm alternating drive operation, the upper arm switching elements 81u, 81v, 81w and the lower arm switching elements 82u, 82v, 82w are not simultaneously turned on, and different phase arms UA, VA, WA are simultaneously turned on. There is nothing to do. Therefore, at most one switching element is always turned on.

[Configuration of DC / DC converter system for executing control method when abnormality is detected]
FIG. 4 shows the configuration of a DC / DC converter system that implements the abnormality detection time control method according to this embodiment. The DC / DC converter system includes an overall control unit 40 that is a higher-level control unit and a converter control unit 48 that is a lower-level control unit.

  The overall control unit 40 operates as an abnormality determination processing unit 202, a control command determination processing unit (control command determination processing unit) 204, and the like, and performs converter control through a communication interface (communication I / F, communication processing unit) 206 and a communication line 38. It communicates with the part 48 and the auxiliary machine 17.

  The abnormality confirmation processing unit 202 performs primary voltage sensor abnormality confirmation processing based on the primary voltage V1, and processes the primary voltage sensor abnormality confirmation flag Fv1d (when the primary voltage sensor abnormality is confirmed: Fv1d = on, primary When the voltage sensor abnormality is not confirmed: Fv1d = off) is output, and the connector abnormality confirmation process is performed. The connector abnormality confirmation flag Fcd of the processing result (when the connector abnormality is confirmed: Fcd = on, when the connector abnormality is not confirmed) : Fcd = off).

  The abnormality confirmation processing unit 202 includes a primary voltage abnormality confirmation timer 268 that counts the time during which the primary voltage abnormality detection flag Fv1 is on as the abnormality confirmation time Tvd, and a supplement when the abnormality of the connector 15 is confirmed. Connection in which the time when the machine 17 is not in the operating state and the primary voltage V1 is equal to or lower than the lower limit voltage threshold value Vthb (a voltage value lower than the voltage value at which the operation of the auxiliary machine 17 cannot be performed) is set as the connector abnormality detection time Tcd. A device abnormality confirmation timer (timer means) 272. The lower limit voltage threshold Vthb is a voltage that the overall control unit 40 recognizes as abnormal when the primary voltage V1 is lower than this value (Vthb). The lower limit voltage threshold Vtha (Vtha <Vthb) is 1 When the primary voltage V1 detected by the primary voltage sensor V1 is lower than this value (Vtha), the secondary voltage abnormality detection unit 224 recognizes an abnormality.

  Control command determination processing unit 204 sends control command CC to converter control unit 48. The control command CC includes a primary voltage control (V1 control) command having the primary voltage V1 as a control value and a secondary voltage control (V2 control) having the secondary voltage V2 as a control value. Command, OFF (OFF: direct connection of primary side 1S and secondary side 2S), transmission of primary voltage command value V1com at the time of primary voltage control, and secondary at the time of secondary voltage control This includes sending the voltage command value V2com, sending the converter operation permission flag Fcao (when permitted: Fcao = on, when not permitted: Fcao = off), and the like.

  The converter control unit 48 includes a primary voltage control unit (V1 control unit) 211, a secondary voltage control unit (V2 control unit) 212, a drive duty 100% storage unit 214, a switch 216, a gate drive signal generation unit 220, 1 In addition to functioning as a secondary voltage abnormality detection unit (V1 abnormality detection unit) 224, a gate cutoff determination unit 226, etc., a communication interface (communication I / F, communication processing unit) 223 and an input interface (input I / F, input processing unit) 225 functions.

  When the primary voltage abnormality detection unit 224 recognizes the abnormality detection of the primary voltage V1, the abnormality detection time is a time during which the abnormality processing primary voltage V1x is equal to or lower than the lower limit threshold voltage Vtha (Vtha <Vthb). An abnormality detection timer (timing means) 270 that counts as Tsd, and a primary voltage abnormality detection flag Fv1 when the abnormality detection time Tsd exceeds the abnormality duration threshold value Tthd (when abnormality is detected: Fv1 = on, when abnormality is not detected: Fv1 = off) and primary voltage temporary abnormal gate cutoff flag Fiag {Fiag is on (Fiag = on) when the primary voltage sensor 91 that detects the primary voltage V1 is presumed to be faulty (abnormal). If it is estimated that there is no failure (abnormality), it is turned off (Fiag = off). } Is output.

  The primary voltage V1x for abnormality processing is an AD (analog-digital) conversion value (AD value) of the primary voltage V1 detected by the primary voltage sensor 91.

  The gate cutoff determination unit 226 outputs a gate cutoff signal Sgc to the gate drive signal generation unit 220 in accordance with the contents of the primary voltage temporary abnormal gate cutoff flag Fiag and a converter operation permission flag Fcoa described later.

  When the gate drive signal generator 220 receives the gate cutoff signal Sgc, it turns off all the gate drive signals Sgd (Sgd = UH, VH, WH, UL, VL, WL).

  FIG. 5 shows a functional block diagram of the secondary voltage control unit 212. The secondary voltage control unit 212 uses the secondary voltage command value V2com supplied from the control command determination processing unit 204 and the deviation ΔV2 calculated by the subtraction unit 240 of the secondary voltage V2 detected by the secondary voltage sensor 92 as PID. The F / B (feedback) term processed by the control unit (proportional integral derivative control unit) 242 is calculated.

  The secondary voltage control unit 212 also calculates the ratio V1 / V2com from the primary voltage V1 detected by the primary voltage sensor 91 and the secondary voltage command value V2com to the F / F (feed forward) term by the division unit 246. Calculate as

  Then, the F / B term and the F / F term are added by the adder 252 and supplied to the gate drive signal generator 220 as the drive duty Ton / T. The gate drive signal generator 220 generates a gate drive signal Sgd (UH, VH, WH, UL, VL, WL) based on this drive duty Ton / T and supplies it to the DC / DC converter 20.

  When the primary voltage abnormality detection flag Fv1 is Fv1 = on state (when the primary voltage V1 detected by the primary voltage sensor 91 is estimated to be abnormal), the secondary voltage control unit 212 switches. 250 is switched to the drive duty 0% storage unit 248 side, and 0 [%] is read out and used as the F / F term. In this case, feedback control is performed using only the F / B term of the secondary voltage V2 based only on the deviation ΔV2.

  During normal running, the secondary voltage control process is executed. In this case, the overall control unit 40 determines the fuel cell 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 17. From the total load request amount of the vehicle 10, the fuel cell shared load amount (required output) to be borne by the fuel cell 14, the battery shared load amount (required output) to be borne by the battery 12, and the regenerative power to be borne by the regenerative power source The distribution (sharing) of the power sharing load 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.

  In the secondary voltage control unit 212 of the converter control unit 48, as described above, the switching element in which the secondary voltage V2 detected by the secondary voltage sensor 92 becomes the secondary voltage command value V2com received from the overall control unit 40. Drive duty Ton / T is calculated.

  FIG. 6 shows a functional block diagram of the primary voltage control unit 211. The primary voltage control unit 211 uses the primary voltage command value V1com supplied from the control command determination processing unit 204 and the deviation ΔV1 calculated by the subtraction unit 260 of the primary voltage V1 detected by the primary voltage sensor 91 as PID. Feedback control is performed only by the F / B (feedback) term processed by the control unit (proportional integral derivative control unit) 262.

  This primary voltage control is executed when an abnormality (open failure) of the connector 15 occurs, and the primary voltage V1 is held at a voltage at which the auxiliary machine 17 operates normally. During the primary voltage control, the secondary voltage V2 is not controlled, but the fuel cell vehicle 10 can be driven by the fuel cell 14.

C. Explanation of Operation Next, the operation of the abnormality detection control method in the DC / DC converter system according to this embodiment will be described with reference to the flowcharts of FIGS. 7, 8, 9, and 10 and the time charts of FIGS. I will explain.

  FIG. 7 shows a flow relating to the primary voltage abnormality detection process executed by the primary voltage abnormality detection unit of the converter control unit 48.

  FIG. 8 shows a flow relating to the gate cutoff determination process executed by the gate cutoff determination unit 226 of the converter control unit 48.

  FIG. 9 shows a flow relating to control command determination processing executed by the control command determination processing unit 204 of the overall control unit 40.

  FIG. 10 is a flowchart related to the open failure determination process of the connector 15 and the detection abnormality (failure of the primary voltage sensor 91) determination process of the primary voltage sensor 91 executed by the abnormality determination processing unit 202 of the overall control unit 40. Show.

  FIG. 11 shows a time chart relating to detection processing when a primary voltage abnormality occurs (when a failure occurs in the primary voltage sensor 91).

  FIG. 12 shows a time chart relating to the detection processing when the open failure of the connector 15 occurs.

  A time chart when the failure of the primary voltage sensor 91 of FIG. 11 occurs will be described generally. When the primary voltage V1x falls below the lower limit voltage threshold value Vtha at time t1, time measurement of the abnormality detection time Tsd in the abnormality detection timer 270 is started at that time, and the abnormality detection time Tsd becomes the abnormality duration threshold value Tthd at time t2. When this occurs, the gate cutoff signal Sgc is turned on, the primary voltage abnormality detection flag Fv1 is turned on, and the primary voltage temporary abnormality gate cutoff flag Fiag is turned on (time t2). The overall control unit 40 starts measuring the primary voltage abnormality confirmation time Tvd by the primary voltage abnormality confirmation timer 268 at time t2. At time t3, the overall control unit 40 turns off (not permitted) the converter operation permission flag Fcoa. Between the time points t2 and t4, it is determined whether the primary voltage sensor 91 is abnormal (voltage detection abnormality) or the connector 15 is abnormal (open failure). When the primary voltage abnormality confirmation time Tvd reaches the primary voltage sensor abnormality duration threshold value Tthc at time t4, the abnormality (failure) of the primary voltage sensor 91 is confirmed (the primary voltage sensor abnormality confirmation flag Fv1d is turned on). The converter operation permission flag Fcoa is turned on (permitted). In this case, it is considered that the primary voltage V1 has decreased due to the abnormality of the primary voltage sensor 91, and V2 control is performed after time t4.

  A time chart when an open failure of the connector 15 in FIG. 12 occurs will be described generally.

  When the primary voltage V1 drops below the lower limit voltage threshold Vthb at time t11, the primary voltage drop timer 274 starts measuring the primary voltage drop time Tlv at that time, and at time t12, the primary voltage drop time Tlv is When the abnormal duration threshold value Ttha is reached, the converter operation permission flag Fcoa is turned off (non-permitted), and the gate cutoff signal Sgc is turned on. Between the time points t11 and t13, it is determined whether the primary voltage sensor 91 is abnormal (voltage detection abnormality) or the connector 15 is abnormal (open failure). When the connector abnormality detection time Tcd reaches the connector abnormality continuation time threshold value Tthb at time t13, the abnormality (open failure) of the connector 15 is confirmed (connector abnormality confirmation flag Fcd is turned on), and the converter is turned on. The operation permission flag Fcoa is turned on (permitted). In this case, since the connector 15 is open, the V1 control is performed after time t13 in order to operate the auxiliary machine 17.

  Next, the abnormality detection process of the converter control unit 48 will be described with reference to the flowchart of FIG.

  In step S41 of FIG. 7, the primary voltage abnormality detection unit 224 of the converter control unit 48 checks whether or not the primary voltage abnormality detection flag Fv1 is on. It is determined whether the voltage V1x is equal to or lower than the lower limit voltage threshold Vtha.

  If the primary voltage V1x is greater than the lower limit voltage threshold value Vtha, the abnormality confirmation processing unit 202 considers that the primary voltage abnormality detection flag Fv1 is also off (step S41: NO), 1 The next voltage sensor 91 is regarded as normal, and the abnormality detection time Tsd of the abnormality detection timer 270 is reset to zero in step S43.

  On the other hand, when the primary voltage V1x is lower than the lower limit voltage threshold value Vtha in step S42 (time t1 in FIG. 11), in step S44, the abnormality detection time Tsd is equal to or greater than the abnormality duration threshold value Tthd (Tsd ≧ If Tsd <Tthd, the abnormality detection time Tsd is increased by unit time in step S45 (Tsd ← Tsd + 1).

  In step S44, when the abnormality detection time Tsd becomes equal to or longer than the abnormality duration threshold Tthd (Tsd ≧ Tthd), the primary voltage abnormality detection flag Fv1 is turned on in step S46 (Fv1 = on, FIG. 11). Time t2).

  Next, in step S47, it is determined whether or not the connector abnormality confirmation flag Fcd is turned on. Since it is not turned on at first, whether or not the primary voltage sensor abnormality confirmation flag Fv1d is turned on in step S48. In step S49, the primary voltage temporary abnormal gate flag Fiag is turned on (time t2 in FIG. 11).

  If the connector abnormality determination flag Fcd is turned on in step S47, it is determined in step S50 whether or not the primary voltage temporary abnormality gate flag Fiag is turned on.

  If the connector abnormality determination flag Fcd is turned on in step S47 and the primary voltage temporary abnormality gate flag Fiag is turned on in step S50, the primary voltage temporary abnormality gate cutoff in step S51. The flag Fiag is turned off and the primary voltage abnormality detection flag Fv1 is turned off.

  If the connector abnormality confirmation flag Fcd is off in step S47 and the primary voltage sensor abnormality confirmation flag Fv1d is on in step S48, the primary voltage temporary abnormality gate is further turned on in step S52. It is determined whether or not the flag Fiag is on. If the flag Fiag is on, the primary voltage temporary abnormality gate flag Fiag is turned off in step S53 (time t4 in FIG. 11).

  In the determination of step S61 in FIG. 8, the gate cutoff determination unit 226 determines that the DC / DC converter 20 determines that the converter operation permission flag Fcoa is on (= permitted) and the primary voltage temporary abnormal gate cutoff flag Fiag is off. In order to permit the operation, the gate cutoff signal Sgc is turned off in step S62. Further, when the converter operation permission flag is off (= not permitted) or the primary voltage temporary abnormal gate cutoff flag Fiag is on in the determination in step S61, the operation of the DC / DC converter 20 is not permitted. In step S63, the gate cutoff signal Sgc is turned on.

  Next, in step S21 of FIG. 10, the abnormality confirmation processing unit 202 confirms whether or not both the primary voltage sensor abnormality confirmation flag Fv1d and the connector abnormality confirmation flag Fcd are off.

  When both the primary voltage sensor abnormality confirmation flag Fv1d and the connector abnormality confirmation flag Fcd are off, in step S22, the abnormality confirmation processing unit 202 determines that the auxiliary machine 17 is not in an operating state and the primary voltage It is determined whether or not V1 is equal to or lower than the lower limit voltage threshold Vthb (V1 ≦ Vthb).

  When the auxiliary machine 17 is in the operating state or the primary voltage V1 is a value exceeding the lower limit voltage threshold value Vthb, it is determined that the connector 15 is closed and normal, and in step S23, the abnormality detection timer 270 is determined. The connector abnormality detection time Tcd is reset to zero.

  Next, in step S24, it is determined whether or not the primary voltage abnormality detection flag Fv1 is turned on. If it is turned off, the abnormality confirmation time Tvd of the primary voltage abnormality confirmation timer 268 is set in step S25. Reset to zero value.

  If the primary voltage abnormality detection flag Fv1 is on in step S24, it is determined in step S26 whether or not the abnormality confirmation time Tvd is equal to or greater than the abnormality duration threshold value Tthc. In step S27, the primary voltage abnormality determination time Tvd is increased by unit time (Tvd ← Tvd + 1).

  If it is determined in step S26 that the abnormality confirmation time Tvd is equal to or greater than the abnormality duration threshold value Tthc, it is determined that the primary voltage sensor 91 is abnormal (failure), and in step S28, the primary voltage sensor abnormality confirmation flag Fv1d. Is turned on and the abnormality (failure) of the primary voltage sensor 91 is determined.

  In step S22 described above, when the auxiliary machine 17 is not in the operating state and the primary voltage V1 is equal to or lower than the lower limit voltage threshold Vthb (V1 ≦ Vthb), the abnormality confirmation processing unit 202 It is determined whether the connector abnormality detection time Tcd counted by the abnormality confirmation timer 272 is equal to or greater than the connector abnormality duration threshold Tthb (Tcd ≧ Tthb). If not, the connection is determined in step S29. The apparatus abnormality detection time Tcd is increased by unit time (Tcd ← Tcd + 1).

  In step S28, when the connector abnormality detection time Tcd measured by the connector abnormality confirmation timer 272 is equal to or longer than the connector abnormality duration threshold Tthb, the connector abnormality confirmation flag Fcd is turned on in step S30. (Fcd = on). Thereby, the abnormality (open failure) of the connector 15 is determined.

  Next, in step S1 of FIG. 9, the control command determination processing unit 204 determines whether the primary voltage V1 for abnormality processing is equal to or lower than the lower limit voltage threshold Vthb.

  If V1> Vthb in step S1, the primary voltage sensor 91 determines that it is normal. In step S2, the abnormality confirmation processing unit 202 determines the primary voltage drop time Tlv (time count) of the primary voltage drop timer 274. Value) to 0.

  Next, in step S3, it is determined whether or not the connector abnormality confirmation flag Fcd is turned on. If it is turned off, the primary voltage sensor 91 is considered to be normal in step S4. Then, the control command CC is set to V2 control (CC ← V2 control), and the converter operation permission flag Fcoa is permitted (Fcoa = on) and sent to the gate cutoff judgment unit 226.

  When the connector abnormality confirmation flag Fcd is on in step S3, the control command CC is set to V1 control in step S5 in consideration of the normal primary voltage sensor 91 (CC (← V1 control) and the converter operation permission flag Fcoa is permitted (Fcoa = on) and sent to the gate cutoff judgment unit 226.

  If V1 ≦ Vthb in the determination by the abnormality determination processing unit 202 in step S1, the primary voltage drop timer 274 starts (continues) counting of the primary voltage drop time Tlv, and the primary voltage in step S6. It is determined whether or not the decrease time Tlv is equal to or greater than the primary voltage sensor abnormality duration threshold value Ttha (Tlv ≧ Ttha).

  If the determination in step S6 is negative, in step S7, the time measured for the primary voltage drop time Tlv is increased by unit time (Tlv ← Tlv + 1).

  In step S6, when the primary voltage drop time Tlv becomes equal to or longer than the abnormality duration threshold value Ttha, in step S8, the abnormality confirmation processing unit 202 determines whether the primary voltage sensor abnormality confirmation flag Fv1d is on ( If the primary voltage sensor abnormality confirmation flag Fvld = on, the cause of the drop in the primary voltage V1 is due to an abnormality (failure) in the primary voltage sensor 91. Then, the secondary voltage control in step S4 is started (time t4 in FIG. 11).

  If the primary voltage sensor abnormality confirmation flag Fv1d is not turned on in step S8 (Fv1d = off), whether or not the connector abnormality confirmation flag Fcd is turned on (is confirmed) in step S9. If the connector abnormality determination flag Fcd is on, it is determined that the cause of the primary voltage drop is an open failure abnormality of the connector 15, and a control command decision is made in step S10. The processing unit 204 sends the V1 control command and the primary voltage command value V1com as the control command CC to the primary voltage control unit 211, and sets the converter operation permission flag Fcoa as permitted (Fcoa = on) to the gate cutoff determination unit 226. Send it out. The gate cutoff determination unit 226 turns off the gate cutoff signal Sgc and sends it to the gate drive signal generation unit 220.

  In this case, the primary voltage control unit 211 shown in FIG. 6 generates the gate drive signal Sgd from the gate drive signal generation unit 220 by the drive duty by the primary voltage feedback control, and the DC / DC converter 20 receives the primary voltage command. It operates by V1 control using the value V1com as a control value (time t13 in FIG. 12). Therefore, even when the connector 15 has an open failure, the primary voltage V1 of the primary side 1S is held at the primary voltage command value V1com, so that the auxiliary machine 17 operates normally.

  If the connector abnormality determination flag Fcd is not turned on in step S9, the control command determination processing unit 204 sets the control command CC to OFF and sends it to the switch 216 in step S11, and also converts the converter operation permission flag. Fcoa is turned off and sent to the gate cutoff judgment unit 226. The gate cutoff determination unit 226 turns on the gate cutoff signal Sgc and sends it to the gate drive signal generation unit 220.

  As described above, the DC / DC converter system according to the embodiment described above is connected to the primary side 1S of the DC / DC converter 20 from the high voltage battery 12 serving as the first power device through the connector 15 that is a connector. In the DC / DC converter system in which the secondary side 2S of the DC / DC converter 20 is connected to the fuel cell 14 as the second power device, the primary voltage sensor is connected to the primary side 1S and detects the primary voltage V1. 91, when the secondary voltage sensor 92 connected to the secondary side 2S detects the secondary voltage V2 and the primary voltage V1 detected by the primary voltage sensor 91 falls below the lower limit threshold value Vthb that is determined to be abnormal. Then, it is determined whether the connector 15 is abnormal (open failure) or the primary voltage sensor 91 detecting the primary voltage V1, and the primary voltage V1 and / or is determined according to the determination result. It includes a converter control unit 48 as a control unit for controlling the DC / DC converter 20 based on the following voltage V2 and the central control unit 40.

  Thus, when the primary voltage V1 is abnormally lowered, the primary voltage sensor that detects the abnormality (open failure) of the connector 15 that connects the battery 12 and the DC / DC converter 20 or the primary voltage V1. Since it is determined whether the abnormality is 91 and the DC / DC converter 20 is controlled according to the determination result, the DC / DC converter 20 can be controlled more appropriately.

  When it is determined that the detection of the primary voltage sensor 91 is abnormal, the DC / DC converter 20 is controlled based on the secondary voltage V2, so that the control of the fuel cell vehicle 10 is not hindered.

  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 contents described in this specification.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell vehicle 11 ... Fuel cell system 12 ... Battery 14 ... Fuel cell 15 ... Connector 16 ... Motor 20 ... DC / DC converter 40 ... General control part 48 ... Converter control part 91 ... Primary voltage sensor

Claims (5)

In a DC / DC converter system in which a first power device is connected to a primary side of a DC / DC converter through a connector, and a secondary side of the DC / DC converter is connected to a second power device.
A primary voltage sensor connected to the primary side for detecting a primary voltage;
A secondary voltage sensor connected to the secondary side for detecting a secondary voltage;
When the primary voltage detection value detected by the primary voltage sensor falls below a lower limit threshold value for determining an abnormality, the primary voltage sensor detects the abnormality of the connector or the primary voltage detection value. A control unit for determining whether or not an abnormality and controlling the DC / DC converter according to the determination result;
A DC / DC converter system comprising: The DC / DC converter system according to claim 1.
An auxiliary machine is further connected to the primary side of the DC / DC converter,
The lower limit threshold value is set to a voltage value lower than a voltage value at which the operation of the auxiliary machine is disabled. The DC / DC converter system, wherein The DC / DC converter system according to claim 1 or 2,
The controller is
When it is determined that the primary voltage sensor is abnormal, the DC / DC converter is controlled based on the secondary voltage. The DC / DC converter system according to any one of claims 1 to 3,
The controller is
When it is determined that the connector is abnormal, the DC / DC converter is controlled based on the primary voltage. In the control method at the time of abnormality detection in the DC / DC converter system in which the first power device is connected to the primary side of the DC / DC converter through the connector, and the secondary side of the DC / DC converter is connected to the second power device.
Detecting a primary voltage which is a voltage on the primary side;
Detecting a secondary voltage which is a voltage on the secondary side;
When the primary voltage detection value falls below a lower limit threshold value for determining abnormality, determining whether the connector is abnormal or voltage detection abnormality, and controlling the DC / DC converter according to the determination result;
An abnormality detection control method in a DC / DC converter system, characterized by comprising:

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