JP4678697B2 - Hybrid power supply vehicle and disconnection control method on first power device side thereof - Google Patents

Description

  The present invention has a first power device that is an electric storage device that is connected to an auxiliary machine and generates a primary voltage, an electric motor that rotates a wheel, and a power generation device that is connected to an inverter that drives the electric motor and generates a generated voltage. A voltage conversion is performed between the primary voltage and the secondary voltage, and a second power device that uses the generated voltage or the regenerative voltage generated in the inverter when the motor operates as a generator as a secondary voltage. TECHNICAL FIELD The present invention relates to a hybrid power supply vehicle including a DC / DC converter to be performed and a disconnection time control method on the first power device side.

  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.

  Further, in a hybrid power supply vehicle as shown in Patent Document 1, power is usually supplied from the battery to auxiliary devices such as lights, power windows, and wiper motors.

  During the regenerative operation of the electric motor, electric power is supplied from the inverter to the auxiliary machine via the DC / DC converter, and the battery is charged.

JP 2007-159315 A

  By the way, in the hybrid power vehicle in which the battery is connected to the auxiliary machine and the battery is connected to the fuel cell and the inverter-driven electric motor via the DC / DC converter, the battery and the DC / DC When disconnection occurs in the power cable connecting to the DC converter, the voltage of the fuel cell is controlled in order to keep the applied voltage to the auxiliary machine connected to the battery side at an appropriate voltage. It is desirable to interrupt and control the voltage on the battery side to protect the auxiliary machine and to operate normally.

  And when a disconnection occurs, it is desirable to quickly control the voltage on the battery side.

  However, since a certain amount of time is required until the disconnection of the power cable connecting the battery and the DC / DC converter is established, there is a problem that the start of the protection operation when the power cable is disconnected is delayed.

  The present invention has been made in consideration of such a problem, and makes it possible to eliminate the delay in the start of the protective operation when the connection between the power storage device such as a battery and the DC / DC converter is disconnected. It aims at providing the control method at the time of a disconnection by the hybrid power supply vehicle and its 1st electric power apparatus side.

  A hybrid power supply vehicle according to the present invention generates a generated voltage by being connected to a first power device comprising a power storage device that is connected to an auxiliary machine and generates a primary voltage, an electric motor that rotates a wheel, and an inverter that drives the electric motor. A second power device having a power generation device and a secondary voltage which is a regenerative voltage generated in the inverter when the power generation voltage or the motor operates as a power generator, and the primary voltage and the secondary voltage A hybrid power supply vehicle having a DC / DC converter that performs voltage conversion between the control unit and a control unit, wherein the control unit outputs the secondary voltage regardless of a direction of a current flowing through the DC / DC converter. A secondary voltage control mode for controlling, and a primary voltage control mode for controlling the primary voltage regardless of the direction of the current flowing through the DC / DC converter. When the possibility of disconnection on the first power device side is detected during the pressure control mode, the secondary voltage control mode is changed to the primary voltage control mode without determining whether or not the disconnection has occurred. It is characterized by switching.

  According to this invention, the control unit controls the secondary voltage regardless of the direction of the current flowing through the DC / DC converter (from the primary side to the secondary side or from the secondary side to the primary side). When the possibility of disconnection of the first power device is detected during the secondary voltage control mode, the primary voltage for controlling the primary voltage from the secondary voltage control mode without determining whether or not it is disconnected. Switch to the control mode. That is, without waiting for the confirmation of the disconnection determination, the secondary voltage control mode is switched from the primary voltage control mode to the primary voltage control mode when the disconnection is suspected. Therefore, protection for ensuring the normal operation of the auxiliary equipment at the time of disconnection The operation can be started immediately.

  In this case, when the control unit further determines during the secondary voltage control mode that the disconnection has not occurred on the first power device side after switching to the primary voltage control mode. When the disconnection has not occurred as a result of returning from the primary voltage control mode to the secondary voltage control mode, the normal voltage control mode is restored to the secondary voltage control mode. be able to.

  The control unit can detect the possibility of disconnection on the first power device side based on the change rate of the primary voltage. For example, if a disconnection occurs when current is flowing from the power storage device, the primary voltage decreases, whereas if a disconnection occurs when current is flowing into the power storage device, The primary voltage increases.

  In this case, the control unit detects the possibility of disconnection on the first power device side based on the rising speed of the primary voltage, and in particular, the regenerative current is changed from the secondary side to the primary side. It is possible to reliably detect disconnection when flowing into the engine, and to continue the operation of the auxiliary machine by switching to the primary voltage control mode.

  Here, the control unit determines a power distribution between the first power device and the second power device in a cycle longer than a processing cycle of the converter control unit that controls the DC / DC converter and the converter control unit. In the secondary voltage control mode, when the possibility of disconnection on the first power device side is detected during the secondary voltage control mode, the secondary control is performed without determining whether or not the disconnection has occurred. By assigning a process for switching from the voltage control mode to the primary voltage control mode to the converter control unit, it is possible to quickly switch from the secondary voltage control mode to the primary voltage control mode when a possibility of disconnection occurs. .

  In this case, it is preferable that a process for detecting the possibility of disconnection on the first power device side based on the change rate of the primary voltage is assigned to the converter control unit.

  Moreover, it is preferable to assign the determination of whether or not a disconnection has occurred on the first power device side to the upper control unit.

  A fuel cell can be applied as the power generation device.

  Each of the above-described inventions can also be implemented as a method invention.

  According to the present invention, when the possibility of disconnection on the first power device side is detected, the secondary voltage control mode is switched from the secondary voltage control mode to the primary voltage control mode at the stage where disconnection is suspected without waiting for the determination of disconnection determination. Therefore, the protection operation for ensuring the normal operation at the time of disconnection of the auxiliary machine connected to the first power device side can be promptly started.

  Thereby, the delay in the start of the protective operation when the connection between the power storage device such as a battery and the DC / DC converter is disconnected can be eliminated.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a device that implements a disconnection control method for a first power device of a hybrid power vehicle according to the present invention will be described with reference to the drawings.

  FIG. 1 is a circuit diagram of a fuel cell vehicle 20 according to an embodiment of a hybrid power vehicle according to the present invention.

  The fuel cell vehicle 20 basically includes a fuel cell 22 that generates a power generation voltage Vf as a power generation device, and a hybrid that includes an energy storage and a power storage device (referred to as a battery) 24 that generates a battery voltage Vbat. Type power supply system, a traveling motor 26 (electric motor) as a load to which current (electric power) is supplied from the hybrid power supply system through the inverter 34, the primary side 1S to which the battery 24 is connected, and the fuel cell 22 A DC / DC converter device {VCU (Voltage Control Unit) that performs voltage conversion of the step-up / step-down voltage between the motor 26 (inverter 34) and the secondary side 2S connected thereto. } 23. The rotation of the motor 26 is transmitted to the wheel 16 through the speed reducer 12 and the shaft 14 to rotate the wheel 16.

  In this embodiment, a 1st electric power apparatus is comprised from the battery 24, and a 2nd electric power apparatus is comprised by the fuel cell 22 and the motor 26 in regenerative operation. In this case, the battery 24 is connected to the primary side 1 </ b> S of the DC / DC converter device 23 via the power line 18.

  The VCU 23 includes a DC / DC converter 36 and a converter control unit 54 as a control unit that drives and controls the switching elements constituting the DC / DC converter 36.

  The fuel cell 22 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 hydrogen tank 28 and an air compressor 30 are connected to the fuel cell 22 by piping. A generated current If generated by an electrochemical reaction of hydrogen (fuel gas), which is a reaction gas, and air (oxidant gas) in the fuel cell 22 is passed through a current sensor 32 and a diode (also referred to as a disconnect diode) 33. And supplied to the inverter 34 and / or the DC / DC converter 36 side.

  The inverter 34 performs DC / AC conversion and supplies the motor current Im to the motor 26, while the motor current Im after AC / DC conversion accompanying the regenerative operation is transferred from the secondary side 2 </ b> S to the primary side through the DC / DC converter 36. Supply to 1S.

  In this case, the primary voltage V1 obtained by converting the secondary voltage V2 which is the regenerative voltage or the generated voltage Vf into a low voltage by the DC / DC converter 36 is stepped down by the downverter 42 to be further reduced to the write, power The auxiliary current 44 is supplied as an auxiliary current Iau to an auxiliary device 44 such as a window or wiper motor, and if there is a surplus in the primary voltage V1, it flows into the battery 24 as the battery current Ibat and charges the battery 24.

  As the battery 24 connected to the primary side 1S, for example, a lithium ion secondary battery, a nickel hydride secondary battery, or a capacitor can be used. In this embodiment, a lithium ion secondary battery is used.

  The battery 24 supplies the auxiliary machine current Iau to the auxiliary machine 44 through the downverter 42, and flows out the battery current Ibat for supplying the motor current Im to the inverter 34 through the DC / DC converter 36.

  The motor current Im supplied to the inverter 34 is a combined current of the secondary current I2 obtained by converting the battery current Ibat by the VCU 23 and the generated current If.

  The downverter 42 has an insulating transformer on the output side, the rectified voltage on the secondary coil side of the insulating transformer is supplied to the positive side of the auxiliary machine 44, and the negative side is grounded to the chassis.

  Smoothing capacitors 38 and 39 are provided on the primary side 1S and the secondary side 2S, respectively. A resistor 40 is connected to the secondary side 2S capacitor 39 in parallel, that is, in parallel to the fuel cell 22.

  The system including the fuel cell 22 is controlled by the FC controller 50, the system including the inverter 34 and the motor 26 is controlled by the motor controller 52 including the inverter driver, and the system including the DC / DC converter 36 includes the converter driver. Each of them is basically controlled by a converter control unit 54 including the above.

  The FC control unit 50, the motor control unit 52, and the converter control unit 54 are controlled by an overall control unit 56 as an upper control unit that determines the total load amount Lt of the fuel cell 22.

  The overall control unit 56, the FC control unit 50, the motor control unit 52, and the converter control unit 54 are respectively an input / output interface such as an A / D converter and a D / A converter in addition to a CPU, a ROM, a RAM, and a timer. In addition, a DSP (Digital Signal Processor) or the like is included as necessary.

  The overall control unit 56, the FC control unit 50, the motor control unit 52, and the converter control unit 54 are connected to each other through a communication line 70 such as a CAN (Controller Area Network) that is an in-vehicle LAN, and are connected to various switches and sensors. Input / output information is shared, and input / output information from these various switches and various sensors is input, and each CPU executes a program stored in each ROM to realize various functions.

  Here, as various switches and various sensors for detecting the vehicle state, in addition to the current sensor 32 for detecting the generated current If, the voltage sensor 61 for detecting the primary voltage V1 (equal to the battery voltage Vbat), the primary current. A current sensor 62 for detecting I1 and a secondary voltage V2 (a voltage sensor 63 for detecting a secondary voltage I2 when the disconnect diode 33 is conductive and substantially equal to the generated voltage Vf of the fuel cell 22) are detected. The current sensor 64, the ignition switch (IGSW) 65 connected to the communication line 70, the accelerator sensor 66, the brake sensor 67, the vehicle speed sensor 68, and the operation unit 55 of the auxiliary device 44 such as the light, power window, and wiper motors described above. Etc.

  The overall control unit 56 determines the fuel cell vehicle based on inputs (load requests) from various switches and various sensors in addition to the state of the fuel cell 22, the state of the battery 24, the state of the motor 26, and the state of the auxiliary machine 44. From the total load requirement amount Lt of 20, the fuel cell shared load amount (required output) Lf to be borne by the fuel cell 22, the battery shared load amount (required output) Lb to be borne by the battery 24, and the regenerative power source The distribution (sharing) of the power regenerative power sharing load amount Lr is determined while arbitrating, and a command is sent to the FC control unit 50, the motor control unit 52, and the converter control unit 54.

  The DC / DC converter 36 includes a switching element such as a MOSFET or an IGBT between the battery 24 (first power device) and the second power device {fuel cell 22 or regenerative power source (inverter 34 and motor 26)}. Three phase arms {U-phase arm UA (81u) composed of upper arm switching element 81 {81u, 81v, 81w (81u to 81w)} and lower arm switching element 82 {82u, 82v, 82w (82u to 82w)} , 82u), a V-phase arm VA (81v, 82v) and a W-phase arm WA (81w, 82w)} are connected in parallel.

  Diodes 83u, 83v, 83w, 84u, 84v, and 84w are connected in parallel to the arm switching elements 81u, 81v, 81w, 82u, 82v, and 82w, respectively.

  When the voltage is converted between the primary voltage V1 and the secondary voltage V2 by the DC / DC converter 36, one reactor 90 for releasing and storing energy is provided for each phase arm (U phase). Arm UA, V-phase arm VA, W-phase arm WA) are inserted between the common connection point at the midpoint and battery 24.

  The upper arm switching elements 81 (81u to 81w) are turned on by gate drive signals (drive voltages) UH, VH, and WH (high levels thereof) output from the converter control unit 54, and the lower arm switching elements 82 (82u) are turned on. ˜82w) are turned on by gate drive signals (drive voltages) UL, VL, WL (high levels thereof), respectively.

  The primary voltage V1, typically the open circuit voltage OCV (Open Circuit Voltage) of the battery 24 when no load is connected, as shown on the fuel cell output characteristics (current voltage characteristics) 91 of FIG. The fuel cell 22 is set to a voltage higher than the minimum voltage Vfmin of the power generation voltage Vf. In FIG. 2, OCV≈V1.

  The secondary voltage V2 is set to a voltage equal to the power generation voltage Vf of the fuel cell 22 when the fuel cell 22 is generating power.

  However, when the power generation voltage Vf of the fuel cell 22 becomes equal to the voltage Vbat (= V1) of the battery 24, a direct connection state indicated by a thick dashed line in FIG. In the direct connection state, when the duty of the drive signals UH, VH, and WH supplied to the upper arm switching element 81 (81u to 81w) is set to 100 [%] and current flows from the secondary side 2S to the primary side 1S. When the upper arm switching element 81 (81u to 81w) is turned on and a current flows through the upper arm switching element 81 (81u to 81w), a current flows from the primary side 1S to the secondary side 2S. .About.83w conduct and current flows through the diodes 83u.about.83w.

  Here, output control of the fuel cell 22 by the VCU 23 will be described.

  During power generation in which fuel gas from the hydrogen tank 28 and compressed air from the air compressor 30 are supplied, the power generation current If of the fuel cell 22 is referred to as a characteristic 91 {function F (Vf) shown in FIG. } Is determined by setting the secondary voltage V2, that is, the generated voltage Vf, through the DC / DC converter 36 by the converter control unit 54. That is, the generated current If is determined as a function F (Vf) value of the generated voltage Vf. If If = F (Vf) and the generated voltage Vf is set to Vf = Vfa = V2, for example, the generated current Ifa as a function value of the generated voltage Vfa (V2) is determined. {Ifa = F (Vfa) = F (V2)}.

  Specifically, in the fuel cell 22, the generated current If as the second source current that flows out in response to a decrease in the generated voltage Vf that is the second output voltage increases, and flows out in response to the increase in the generated voltage Vf. The generated current If decreases.

  As described above, since the fuel cell 22 determines the generated current If by determining the secondary voltage V2 (generated voltage Vf), in a system including the fuel cell 22 such as the fuel cell vehicle 20, the DC / DC is normally used. Secondary voltage V2 (power generation voltage Vf) on secondary side 2S of converter 36 is set to a target voltage (target value) of feedback control of VCU 23 including converter control unit 54. That is, the output (generated current If) of the fuel cell 22 is controlled by the VCU 23. The above is the description of the output control of the fuel cell 22 by the VCU 23.

  However, in a special case where the battery 24 (first power device) is considered to be in failure, such as when the battery 24 is opened due to a disconnection failure of the power line 18 between the downverter 42 and the battery 24, as described later. The primary voltage V1 is set as a target voltage for feedback control by the VCU 23.

  The fuel cell vehicle 20 according to this embodiment is basically configured and operates as described above, and next includes a disconnection detection operation process of the power line 18 by the converter control unit 54 and the overall control unit 56. The operation of the fuel cell vehicle 20 will be described with reference to the flowcharts of FIGS.

  When the power line 18 is not disconnected normally, the secondary voltage V2 control mode in step S1 of FIG. 3 is performed.

  In the secondary voltage V2 control mode, as described above, the overall control unit 56 performs various switches and various in addition to the state of the fuel cell 22, the state of the battery 24, the state of the motor 26, and the state of the auxiliary machine 44. From the total load request amount Lt of the fuel cell vehicle 20 determined based on the input (load request) from the sensor, the fuel cell shared load amount (request output) Lf to be borne by the fuel cell 22 and the battery to be borne by the battery 24 The allocation (sharing) of the shared load amount (required output) Lb and the regenerative power source shared load amount Lr to be borne by the regenerative power source is determined while arbitrating, and commands are issued to the FC control unit 50, motor control unit 52, and converter control unit 54 Is sent out.

  FIG. 4 shows details of the process in step S1 of FIG. In step S11, when the overall control unit 56 determines (calculates) the total load request amount Lt from the electric power request of the motor 26, the electric power request of the auxiliary machine 44, and the electric power request of the air compressor 30, which are load requests, respectively. In step S12, the overall control unit 56 determines the distribution of the fuel cell shared load amount Lf, the battery shared load amount Lb, and the regenerative power source shared load amount Lr for outputting the determined total load request amount Lt, and FC Commands are given to the control unit 50, the converter control unit 54, and the motor control unit 52. Here, when determining the fuel cell shared load Lf, the efficiency η of the fuel cell 22 is considered.

  Next, in step S <b> 13, the fuel cell shared load determined by the overall control unit 56 (substantially includes the command voltage V <b> 2 com of the generated voltage Vf for the converter control unit 54) Lf is transmitted through the communication line 70 to the converter control unit. 54 is transmitted as a command.

  In step S14, the converter control unit 54 that has received the command for the fuel cell shared load amount Lf uses the secondary voltage V2, in other words, the generated voltage Vf of the fuel cell 22 to the command voltage V2com commanded from the overall control unit 56. The drive duty of the switching elements (81u to 81w, 82u to 82w) of the DC / DC converter 36 (drive signals UH to WH, ON duty of UL to WL) is controlled so that The secondary voltage V2 (or primary voltage V1) is controlled by the converter control unit 54 by a PID operation in which the DC / DC converter 36 is combined with feedforward control and feedback control.

  Further, the FC control unit 50 and the motor control unit 52 also execute predetermined processing in response to a command from the overall control unit 56.

  Then, control results are sequentially reported from the FC control unit 50, the converter control unit 54, and the motor control unit 52 to the overall control unit 56.

  Here, the processing cycle by the overall control unit 56 is, for example, the processing of the converter control unit 54 in consideration of the fact that the fuel cell vehicle 20 may respond smoothly to the user's accelerator operation or the like without causing a sense of incongruity. The cycle may be slower than the cycle (in this embodiment, the switching cycle≈50 [μS]), for example, set between 1 and 1000 [mS] (in this embodiment, approximately 10 [ms], 200 times the switching cycle). Is done. Note that the processing cycle of the converter control unit 54 is set between 1 and 1000 [μS], for example.

  Here, the step-up operation during the secondary voltage V2 control mode in which the secondary voltage V2 is controlled to become the command voltage V2com in step S1 (step S14) will be described.

  When the command voltage V2com is determined by the overall control unit 56 during the boosting operation, the converter control unit 54 causes the lower arm switching elements 82u to 82u to keep the secondary voltage V2 at the command voltage V2com that is the target voltage. The drive signals UL to WL in which the drive duty (on duty) of 82w is 1-V1 / V2com are generated. Note that drive signals UH to WH having a duty of (1−on-duty of the drive signals UL to WL = V1 / V2com) are also generated.

  As shown in FIG. 5, in the step-up operation for supplying the secondary current I2 from the secondary side 2S of the DC / DC converter 36 to the inverter 34 side, the converter control unit 54, for example, at the time t13 to t14, the lower arm switching element 82u is turned on. At this time, energy is stored in the reactor 90 by the primary current I1 obtained by subtracting the auxiliary machine current Iau from the battery current Ibat, and at the same time, the secondary current I2 is supplied from the capacitor 39 to the inverter 34.

  Further, when the lower arm switching elements 82u to 82w are turned off at the time t14 to t17, the diodes 83u to 83w are turned on, discharge energy from the reactor 90, accumulate energy in the capacitor 39, and secondary current I2. To the inverter 34.

  Further, when the lower arm switching element 82v is turned on at time t17, energy is stored again in the reactor 90, and thereafter, when the lower arm switching elements 82u to 82w are turned off, current is supplied to the diodes 83u to 83w. Flowing. Thereafter, when the lower arm switching element 82w is turned on and then turned off, a current flows through the diodes 83u to 83w, and when the lower arm switching element 82u is turned on and turned off, a current flows through the diodes 83u to 83w. Such a process is repeated and the DC / DC converter 36 is rotationally switched.

  Next, the step-down operation during the secondary voltage V2 control mode in which control is performed so as to become the command voltage V2com in step S1 (step S14) will be described.

  When the command voltage V2com is determined by the overall control unit 56 during the step-down operation, the converter control unit 54 controls the upper arm switching elements 82u to 82u so that the secondary voltage V2 is held at the command voltage Vcom that is the target voltage. The drive signals UH to WH in which the drive duty (on duty) of 82w is V1 / V2com are generated. Note that drive signals UL to WL whose duty is (1—on-duty of the drive signals UH to WH = 1−V1 / V2com) are also generated.

  As shown in FIG. 6, in the step-down operation for supplying the secondary current I2 from the secondary side 2S of the DC / DC converter 36 to the auxiliary device 44 and the battery 24 of the primary side 1S, the converter control unit 54 At t2, the upper arm switching element 81u is turned on. At this time, the reactor 90 has firstly a secondary current I2 due to the motor current Im (generator current) as a regenerative current from the secondary side 2S, secondly a secondary current I2 due to the generated current If, or thirdly The secondary current I2 resulting from the combined current of the regenerative motor current Im and the generated current If flows as the primary current I1 and accumulates energy in the reactor 90. At the same time, the auxiliary battery 44 from the capacitor 38 and the battery as required. 24 is supplied with a primary current I1.

  Next, when the upper arm switching elements 81u to 81w are turned off at time points t2 to t5, current flows through the diodes 84u to 84w, energy is released from the reactor 90, energy is stored in the capacitor 38, and compensation is performed. The primary current I1 is supplied to the battery 24 and the battery 24 on demand.

  Further, when the upper arm switching element 81v is turned on and turned off at time t5, a current flows through the diodes 84u to 84w. Thereafter, when the upper arm switching element 81w is turned on and turned off, a current flows through the diodes 84u to 84w, and the upper arm When the switching element 81u is turned on and then turned off, a current flows through the diodes 84u to 84w. Such a process is repeated and the DC / DC converter 36 is rotationally switched.

  During the process of step S1, the converter control unit 54 performs a process for detecting the possibility of disconnection of the power line 18 in step S2 every switching cycle 2π (corresponding to a time of about 50 [μs] in this embodiment). .

  In the disconnection detection processing of the power line 18, the change rate (rising speed or descending speed) VS1 [V / s] ([V / s] = [volt / second]) of the primary voltage V1 detected by the voltage sensor 61 is calculated. Detect (calculate).

  When the power line 18 is disconnected while the battery current Ibat is flowing out from the battery 24 as a discharge current, the primary voltage V1 starts to decrease rapidly. On the other hand, when the power line 18 is disconnected while the battery current Ibat flows into the battery 24 as the charging current, the primary voltage V1 starts to increase rapidly.

Therefore, when the change speed VS1 of the primary voltage V1 is larger than the threshold speed VSref in step S2, it is estimated that the power line 18 has been disconnected (assuming that there is a possibility of disconnection), and immediately, step S3. The primary voltage V1 control mode is shifted to.

  Note that the threshold speed VSref is determined in advance by simulation and experimentation at both the rising speed and the falling speed of the primary voltage V1, for example, during design development. In this case, a table (map) of the respective threshold speeds VSref of the ascending / descending change speeds can be created according to the current values of the primary current I1 and the battery current Ibat and the load of the auxiliary machine 44.

  In step S2, the converter control unit 54 estimates that the power line 18 is disconnected when the change speed VS1 of the primary voltage V1 exceeds the threshold speed VSref, and starts from the secondary voltage V2 control mode to the primary of step S3. Transition to the voltage V1 control mode (switching control mode). In step S3, converter control unit 54 notifies general control unit 56 that the transition from the secondary voltage V2 control mode to the primary voltage V1 control mode has started.

  In the primary voltage V1 control mode of step S3, when the operating range of the downverter 42 is wide, the primary voltage V1 when the change speed VS1 of the primary voltage V1 exceeds the threshold speed VSref is used as the target voltage. However, when the operation range of the downverter 42 is narrow, the primary voltage V1 at the time when the change speed VS1 of the primary voltage V1, which is the previous time, starts to rise or fall, is set to DC / By controlling the DC converter 36, an excessive current or an excessive current does not flow through the auxiliary machine 44 in any case where the operating range of the downverter 42 is wide or narrow, and the normal operation of the auxiliary machine 44 is ensured. Can do.

  That is, by controlling in this way, the downverter 42 can continue normal operation and normal current can be supplied to the auxiliary device 44, so that the auxiliary device 44 can continue normal operation.

  As described above, by detecting the presence or absence of disconnection of the power line 18 based only on the change speed VS1 of the primary voltage V1, the disconnection determination time can be made extremely short. That is, the disconnection detection can be speeded up.

  Next, in step S4, the overall control unit 56 receives a notification that the transition from the secondary voltage V2 control mode to the primary voltage V1 control mode is started from the converter control unit 54 for a few seconds (from 2 to 3 seconds). After a lapse of 5-6 seconds, a disconnection determination is performed in step S5. The overall control unit 56 determines that the power line 18 has been disconnected for a few seconds, for example, when determining that the auxiliary machine current Iau is all covered by the primary current I1 (Iau≈I1).

  On the other hand, in step S5, the overall control unit 56 covers, for example, the auxiliary device current Iau even with the battery current Ibat during the passage of several seconds in step S4 {including the case of Iau = Ibat + I1 (including the case of I1 = 0). }, It is determined that the disconnection possibility determined in step S2 is an error (step S5: NO), and the secondary voltage V2 control mode in step S1 from the current primary voltage V1 control mode. Return (return control mode).

  In step S5, if the disconnection possibility determined in step S2 is correct and it is determined that the disconnection is actually performed (step S5: YES), the operation in the primary voltage V1 control mode is continued in step S6. To do.

  In this case, in step S7, the overall control unit 56 uses the power line 18 connected to the power storage device 24 by sound from a speaker (not shown) and / or display on a display (not shown) on the dashboard. The user is warned of the disconnection. Note that a similar warning notification may be made in step S3 with the content that the power line 18 may be disconnected.

  As described above, according to the above-described embodiment, in step S2, the converter control unit 54 may disconnect the power line 18 of the power storage device 24 that is the first power device based on the change speed VS1 of the primary voltage V1. Is detected, without waiting for confirmation of the disconnection determination by the overall control unit 56 in step S5, the secondary voltage V2 control mode is changed to the primary voltage V1 control mode at the stage where disconnection is suspected (step S2: YES). Since the switching is performed (step S3), the protection operation for ensuring the normal operation of the auxiliary machine 44 when the power line 18 is disconnected can be quickly started. That is, it is possible to eliminate the delay in the start of the protective operation when the connection between the power storage device 24 and the DC / DC converter 36 is disconnected.

  Thus, if disconnection is detected only by the change rate VS1 of the primary voltage V1, the determination time for disconnection detection is shortened (an example of speeding up disconnection detection). However, when the fuel cell vehicle 20 shifts from acceleration to deceleration, the regenerative current may increase rapidly. If the primary voltage V1 rises rapidly with a sudden increase in the regenerative current, this sudden rise in the primary voltage V1 is erroneously determined as a disconnection, and the primary voltage V1 control mode is switched due to erroneous detection. there is a possibility.

  In order to prevent disconnection error detection due to such a sudden regenerative current, the limit of the regenerative current increase rate, the so-called rate limit (increase amount of regenerative current per unit time) is suppressed to a small value and false detection It is also conceivable to prevent a sudden change in the primary voltage V1 leading to (Example 1 of false detection countermeasures). However, if the rate of increase of the regenerative current is excessively limited (rate limit), the degree of freedom in adjusting the regenerative current (regeneration amount) during normal travel is reduced, and the target vehicle running performance may not be achieved.

  In view of this, it is conceivable to set the control switching threshold (rate limit threshold) for limiting the increase rate of the regenerative current to a large value. However, when the threshold value of the rate limit is set to a large value, there may occur a case where the above-described simple disconnection determination (step S2) for monitoring the change speed VS1 of the primary voltage V1 does not operate. As shown in the flowchart of the comparative example of the disconnection detection processing operation in FIG. 7, the steps S2 and S3 are changed so as to be omitted, but when the control flow is changed in this way, the control of step S5 in FIG. Until the disconnection detection by the control unit 56 is confirmed, the mode switching from the secondary voltage V2 control mode to the primary voltage V1 control mode does not occur, and the start of the protection control may be delayed.

  On the other hand, in the control flow according to this embodiment shown in FIG. 3, the control mode is switched from the secondary voltage V2 control mode to the primary voltage V1 control mode at the stage where disconnection is suspected (step S2: YES). At the same time, when there is no actual disconnection (step S5: NO), the configuration is such that the original secondary voltage V2 control mode (step S1) is restored. Both driving performance can be achieved.

  The present invention is not limited to the above-described embodiment, and based on the description in this specification, for example, when a protective relay (protective switch) is provided in series with the power storage device 24, the protective relay is opened. Of course, it is possible to adopt various configurations such that step S2 is established when it is determined (including determination of erroneous opening).

1 is a circuit diagram of a fuel cell vehicle according to an embodiment of the present invention. It is explanatory drawing of the current-voltage characteristic of a fuel cell. It is a flowchart with which it uses for description about the disconnection detection process operation | movement of the power line by a converter control part and an integrated control part. It is a flowchart provided by description about the basic operation | movement of the DC / DC converter drive-controlled by the converter control part. It is a time chart used for operation | movement description of the pressure | voltage rise operation of a DC / DC converter apparatus. It is a time chart used for operation | movement description of the pressure | voltage fall operation | movement of a DC / DC converter apparatus. It is a flowchart of the comparative example of a disconnection detection processing operation.

Explanation of symbols

20 ... Fuel cell vehicle 22 ... Fuel cell 23 ... DC / DC converter unit (VCU)
24 ... Power storage device (battery) 26 ... Motor 34 ... Inverter 36 ... DC / DC converter 54 ... Converter control unit 56 ... Overall control unit

Claims (8)

A first electric power device comprising a power storage device connected to an auxiliary machine and generating a primary voltage; an electric motor for rotating a wheel; and an electric generator connected to an inverter for driving the electric motor and generating an electric power generation voltage, Alternatively, a second power device that uses a regenerative voltage generated in the inverter as a secondary voltage when the motor operates as a generator, and DC / DC that performs voltage conversion between the primary voltage and the secondary voltage A hybrid power vehicle comprising a converter,
Having a control unit,
The controller is
A secondary voltage control mode for controlling the secondary voltage regardless of the direction of the current flowing through the DC / DC converter;
A primary voltage control mode for controlling the primary voltage regardless of the direction of the current flowing through the DC / DC converter,
During the secondary voltage control mode, the possibility of disconnection of the power line connecting the first power device and the DC / DC converter is detected by whether or not the change speed of the primary voltage is greater than a threshold speed. When the possibility of disconnection of the power line is detected, the hybrid power supply vehicle is switched from the secondary voltage control mode to the primary voltage control mode without determining whether or not the power line is disconnected. The hybrid power supply vehicle according to claim 1,
The control unit further includes:
In the secondary voltage control mode, after switching to the primary voltage control mode, if it is determined that the power line is not disconnected, the secondary voltage is switched from the primary voltage control mode to the secondary voltage control mode. A hybrid power vehicle characterized by returning to a control mode. The hybrid power supply vehicle according to claim 1 or 2 ,
The controller is
The hybrid power supply vehicle, wherein the possibility of disconnection of the power line is detected based on a rising speed of the primary voltage. The hybrid power supply vehicle according to any one of claims 1 to 3 ,
The control unit
A converter control unit for controlling the DC / DC converter;
A higher control unit that determines power distribution of the first power device and the second power device in a cycle longer than the processing cycle of the converter control unit;
Processing for switching from the secondary voltage control mode to the primary voltage control mode without determining whether or not the power line is disconnected when the possibility of disconnection of the power line is detected during the secondary voltage control mode Is assigned to the converter control unit. The hybrid power vehicle according to claim 4 , wherein
A hybrid power supply vehicle, characterized in that processing for detecting the possibility of disconnection of the power line based on a change rate of the primary voltage is assigned to the converter control unit. In the hybrid power supply vehicle according to claim 4 or 5 ,
A hybrid power supply vehicle characterized in that a determination as to whether or not a break in the power line has occurred is assigned to the upper control unit. The hybrid power supply vehicle according to any one of claims 1 to 6 ,
The hybrid power supply vehicle, wherein the power generation device is a fuel cell. A first electric power device comprising a power storage device connected to an auxiliary machine and generating a primary voltage; an electric motor for rotating a wheel; and an electric generator connected to an inverter for driving the electric motor and generating an electric power generation voltage, Alternatively, a second power device that uses a regenerative voltage generated in the inverter as a secondary voltage when the motor operates as a generator, and DC / DC that performs voltage conversion between the primary voltage and the secondary voltage In a disconnection time control method on the first power device side of a hybrid power supply vehicle comprising a converter,
A processing procedure controlled in a secondary voltage control mode for controlling the secondary voltage regardless of the direction of the current flowing through the DC / DC converter;
A processing procedure for controlling in a primary voltage control mode for controlling the primary voltage regardless of the direction of the current flowing through the DC / DC converter;
During the secondary voltage control mode, the possibility of disconnection of the power line connecting the first power device and the DC / DC converter is detected by whether or not the change speed of the primary voltage is greater than a threshold speed. A processing procedure for controlling in the switching control mode for switching from the secondary voltage control mode to the primary voltage control mode, without determining whether or not the power line is disconnected, when the possibility of disconnection of the power line is detected; ,
The control method at the time of a disconnection by the side of the 1st electric power apparatus of the hybrid power supply vehicle characterized by comprising.

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