JP2018121397A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that enables an electric vehicle to continue traveling for a long time in the event that an abnormal state arises in a voltage converter.SOLUTION: An electric vehicle comprises: a high voltage battery; high voltage wiring; a low voltage battery; low voltage wiring; a first voltage converter and a second voltage converter connected in parallel between the high voltage wiring and the low voltage wiring; a high-order apparatus and a low-order apparatus connected in parallel to the low voltage wiring. The control device comprises: voltage converter abnormality handling means that performs a voltage converter abnormality handing process in which in a case where abnormality arises in one of the first voltage converter and the second voltage converter, the operation of the voltage converter in the abnormal state is stopped and the operation of the voltage converter in a normal state is continued; and priority processing means that performs a priority process in which in a case where the total output power, obtained by totalizing power that can be output by the voltage converter continuing the operation and the power that can be output by the low voltage battery is equal to or less than drive power used for driving the high-order apparatus, the operation of the low-order apparatus is stopped and the operation of the high-order apparatus is continued.SELECTED DRAWING: Figure 2

Description

  In this specification, the technique of continuing driving | running | working after abnormality generate | occur | produces in an electric vehicle is disclosed.

As shown in Patent Document 1, an electric automobile including a high voltage battery and a low voltage battery is known. The high voltage battery supplies drive power to, for example, a traveling motor, and the low voltage battery applies drive voltage to, for example, an electric steering device or an air conditioner device. In the present specification, a device driven by the power supplied from the high voltage battery is referred to as a high voltage device, and a device driven by the voltage applied by the low voltage battery is referred to as a low voltage device. A voltage converter may be inserted between the high voltage battery and the high voltage device, and the drive voltage of the high voltage device may not match the output voltage of the high voltage battery.
There is also known an electric vehicle in which a first voltage converter and a second voltage converter are connected in parallel between a high voltage wiring to which a voltage of a high voltage battery is applied and a low voltage wiring to which a voltage of a low voltage battery is applied. ing. Each of the first voltage converter and the second voltage converter steps down the voltage provided by the high voltage battery and supplies it to the low voltage wiring. The low voltage power provided from each of the first voltage converter and the second voltage converter charges the low voltage battery or is supplied to the low voltage device.

  One (eg, short circuit) may occur in one of the two voltage converters. In order to allow the electric vehicle to continue running even if an abnormality occurs, the control device for the voltage converter is provided with an abnormality processing means. The abnormality processing means stops the operation of the voltage converter in which the abnormality has occurred and continues the operation of the voltage converter that operates normally. Since the abnormality processing means is prepared, when an abnormality occurs, the operation of the low-voltage device is continued by the power supplied by the normally operating voltage converter and the power supplied by the low-voltage battery, and the electric vehicle continues to run. .

JP, 2006-101057, A

The low-voltage battery is discharged while the operation of the low-voltage device is continued by the power supplied by the normally operating voltage converter and the power supplied by the low-voltage battery, and the drive power necessary for the operation of the low-voltage device cannot be supplied. As the discharge of the low-voltage battery progresses, it becomes difficult to continue running the electric automobile.
In the present specification, a technique for extending the travel time or travel distance of an electric automobile under the above-described circumstances is disclosed.

Among the low-voltage equipment driven by the voltage of the low-voltage battery, there are equipment that is indispensable to continue running, such as an electric steering device and a shift-by-wire device, and equipment that can continue running even if the operation is stopped, such as an air conditioner device. Exists. In the present specification, the former is referred to as a high-order device, and the latter is referred to as a low-order device.
Conventional technology does not distinguish between high-order equipment and low-order equipment. That is, when the total power of the power supplied by the normal voltage converter and the power supplied by the low voltage battery is defined as the total output power, “total output voltage <total drive power of (high-order device and low-order device)” When the relationship is reached, the power supply to the high-order equipment and low-order equipment is insufficient. The total output power is even lower than in this case, and when the relationship of “total output voltage <drive power of high-order equipment” is reached, the shortage of power supplied to the high-order equipment and low-order equipment becomes noticeable. It becomes difficult to continue.
When “total output voltage <drive power of high-order equipment”, even if only high-order equipment is operated (in other words, low-order equipment is not operated), supply to high-order equipment The power is not enough. However, since the power supplied to the low-order equipment is saved, the operable period of the high-order equipment is extended. In the technology of the present specification, even after the relationship of “total output voltage <drive power of high-order equipment” is established, the high-order equipment continues to run and continue to travel.

The electric vehicle disclosed in this specification includes a high voltage battery, a high voltage wiring to which a voltage of the high voltage battery is applied, a low voltage battery, a low voltage wiring to which a voltage of the low voltage battery is applied, a high voltage wiring and a low voltage wiring. A first voltage converter and a second voltage converter that are connected in parallel with each other, a high-order device and a low-order device that are connected in parallel to the low-voltage wiring, and a control device.
The control device stops the operation of the abnormal voltage converter and continues the operation of the normal voltage converter when an abnormality occurs in one of the first voltage converter and the second voltage converter. The total output power of the voltage converter abnormality processing means that executes the converter abnormality processing and the power that can be output by the voltage converter that continues to operate and the power that can be output by the low-voltage battery is high-order equipment. And a priority processing means for executing priority processing for stopping the operation of the low-order device and continuing the operation of the high-order device.

According to the above configuration, when the relationship of “total output voltage <drive power of high-order equipment” is established, the operation of the low-order equipment is stopped and the operation of the high-order equipment is continued. If equipment that is indispensable for driving in an abnormal situation is designated as a high-priority equipment, and equipment that is not indispensable for running in an abnormal situation is designated as a low-priority equipment, it is possible to extend the operating period of equipment indispensable for running in an abnormal situation. .
Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric system of the electric vehicle of 1st Example. It is a flowchart of the process which a system controller performs. It is a block diagram of the electric system of the electric vehicle of 2nd Example.

(First embodiment)
A hybrid vehicle 2 of the first embodiment (an embodiment of an electric vehicle) will be described with reference to FIG. The hybrid vehicle 2 of the first embodiment includes a motor 6 and an engine 91 that generate driving torque for traveling. The output shaft of the motor 6 and the output shaft of the engine 91 are connected to the transmission 92. The driving torque of the motor 6 and the driving torque of the engine 91 are combined by the transmission 92 and transmitted to the axle 93. The transmission 92 may distribute the driving torque of the engine 91 to the motor 6 and the axle 93. In that case, the hybrid vehicle 2 generates electric power by driving the motor 6 in the reverse direction with the remainder of the driving torque while traveling with a part of the driving torque of the engine 91. When the driver steps on the brake, the motor 6 generates electricity using the kinetic energy of the vehicle. The electric power obtained by power generation is stored in the main battery 3 described later.

  The motor 6 is driven by the power of the main battery 3 (an example of a high voltage battery). The output voltage of the main battery 3 is 300 volts, for example. The motor 6 is a three-phase AC motor, and its drive voltage is, for example, 600 volts. The power converter 5 boosts the voltage of the DC power of the main battery 3 and then converts it into AC power suitable for driving the motor 6. When the motor 6 generates power, the power converter 5 converts the AC power output from the motor 6 into DC and then steps down to the output voltage of the main battery 3.

  The main battery 3 and the power converter 5 are connected by a main power line 28. The voltage of the main battery 3 is applied to the positive line of the main power line 28, which is an example of high voltage wiring. The system main relay 4 is connected in the middle of the main power line 28. The system main relay 4 is closed by a system controller 29 when a vehicle main switch (not shown) is turned on, and the main battery 3 and the power converter 5 are electrically connected. Note that “close the relay (close the switch)” means that both ends of the relay (both ends of the switch) are electrically connected. The expression “close the relay (close the switch)” may be expressed as “turn on the relay (turn on the switch)”. Conversely, “opening the relay (opening the switch)” means electrically disconnecting both ends of the relay (both ends of the switch). The expression “open relay (open switch)” may be expressed as “turn relay off (switch off)”.

  The system controller 29 is supplied with electric power from an auxiliary battery 7 (an example of a low voltage battery) described later, and can operate even when the system main relay 4 is open. When the main switch of the vehicle is turned off, the system controller 29 opens the system main relay 4 to electrically disconnect the main battery 3 and the power converter 5.

  The hybrid vehicle 2 further includes an auxiliary battery 7, a first voltage converter 11, a second voltage converter 12, auxiliary machine groups 8, 29, 31, a first diode 9a, and a second diode 9b.

  The auxiliary battery 7 is a battery for supplying electric power to a group of auxiliary machines such as the shift-by-wire device 8, the system controller 29, and the air conditioner 31. The output voltage of the auxiliary battery 7 is, for example, 12 volts, and the auxiliary battery 7 is an embodiment of a low voltage battery. The auxiliary battery 7 applies a voltage to the first auxiliary power line 21 and the third auxiliary power line 23. The first auxiliary power line 21, the third auxiliary power line 23, and the second auxiliary power line 22 described later are examples of low voltage wiring. The output voltage of the auxiliary battery 7 is equal to the drive voltage of the shift-by-wire device 8, the system controller 29, and the air conditioner device 31. The shift-by-wire device 8, the system controller 29, the air conditioner 31 and the like are examples of low-voltage equipment.

  The first voltage converter 11 (embodiment of the first voltage converter) and the second voltage converter 12 (embodiment of the second voltage converter) step down the output voltage of the main battery 3 to the driving voltage of the auxiliary machine. It is a converter. The first voltage converter 11 and the second voltage converter 12 are connected in parallel to the main power line 28. The input terminal 11 a of the first voltage converter 11 is connected to the main battery 3 via the system main relay 4. The output terminal 11 b of the first voltage converter 11 is connected to the positive electrode of the auxiliary battery 7 through the first auxiliary power line 21. Note that the negative electrode of the auxiliary battery 7 is connected to the ground G. The negative poles of the shift-by-wire device 8, the system controller 29, the air conditioner device 31, and the auxiliary battery 7 are conducted through the ground G. The ground G is a conductive body of the vehicle.

  The input terminal 12 a of the second voltage converter 12 is connected to the main battery 3 without passing through the system main relay 4. The output terminal 12 b of the second voltage converter 12 is connected to the power input terminal 8 a of the shift-by-wire device 8 and the power input terminal 29 a of the system controller 29 by the second auxiliary power line 22.

  The auxiliary machine groups 8, 29, and 31 are low-voltage equipment groups that operate at a voltage lower than the output voltage of the main battery 3. The auxiliary machine groups 8, 29, and 31 are connected in parallel to the auxiliary machine power lines 21 to 23. Among the auxiliary machine groups 8, 29 and 31, there are high-order equipment that is indispensable for continuing running and low-order equipment that can continue running even if the operation is stopped. The shift-by-wire device 8 and the system controller 29 are examples of high-order equipment. The air conditioner 31 is an example of a low-order device. The power input terminal 8 a of the shift-by-wire device 8 and the power input terminal 29 a of the system controller 29 are connected to the positive electrode of the auxiliary battery 7 through the third auxiliary power line 23. The power input terminal 31a of the air conditioner 31 is also connected to the positive electrode of the auxiliary battery 7 via the third auxiliary power line 23 and a switch 14 described later.

  Although illustration is omitted, in addition to the shift-by-wire device 8 and the system controller 29, various high-order devices (for example, an electric power steering, an automatic driving engine control unit, etc.) are connected, and the air conditioner 31 In addition, various low-order devices (for example, audio devices) are connected. The high-order device is connected to the voltage converters 11 and 12 without passing through the switch 14, and the low-order device is connected to the voltage converters 11 and 12 through the switch 14. In this embodiment, the shift-by-wire device 8 and the system controller 29 are representative of high-order equipment, and the air conditioner 31 is representative of low-order equipment.

  A first diode 9 a is connected to the third auxiliary power line 23. The anode of the first diode 9a is connected to the auxiliary battery 7 side, and the cathode is connected to the shift-by-wire device 8 and the system controller 29 side. The first diode 9 a is provided to prevent a current backflow from the shift-by-wire device 8 or the system controller 29 to the auxiliary battery 7. A second diode 9 b is connected to the second auxiliary power line 22. The anode of the second diode 9 b is connected to the second voltage converter 12, and the cathode is connected to the shift-by-wire device 8 and the system controller 29. The second diode 9 b is provided to prevent a current backflow from the shift-by-wire device 8 or the system controller 29 to the second voltage converter 12.

  An abnormality may occur in the first voltage converter 11, and the voltage of the output 11b may not rise from the ground voltage. Even in such a case, if the second voltage converter 12 is normal, the first diode 9a is provided, so that power is supplied from the second voltage converter 12 and the auxiliary battery 7 to the shift-by-wire device 8 and the system controller 29. It is possible to supply power to the air conditioner 31 from the auxiliary battery 7.

  An abnormality may occur in the second voltage converter 12 and the voltage of the output 12b may not rise from the ground voltage. Even in that case, if the first voltage converter 11 is normal, the second diode 9b is provided, so that the shift-by-wire device 8, the system controller 29, and the air conditioner device are provided from the first voltage converter 11 and the auxiliary battery 7. Power can be supplied to 31.

  The system controller 29 controls the opening and closing of the switch 14 by executing the processing of FIG. In the initial state of FIG. 2, the switch 14 is closed. In S10, the system controller 29 determines whether or not an abnormality has occurred in the first voltage converter 11. For example, when the output voltage of the first voltage converter 11 is smaller than the target value, the system controller 29 may determine YES in S10, or when communication with the first voltage converter 11 is disabled, the system controller 29 You may decide YES. If the system controller 29 determines YES in S10, it proceeds to S20. On the other hand, if the system controller 29 determines NO in S10, it proceeds to S40.

  In S <b> 20, the system controller 29 stops the operation of the first voltage converter 11 and continues the operation of the second voltage converter 12. In this case, power is supplied from the main battery 3 to the high-order devices 8 and 29 via the second voltage converter 12 and also from the auxiliary battery 7. Power is supplied from the auxiliary battery 7 to the low-order equipment 31.

In S30, the system controller 29 determines whether or not the total output power obtained by summing the output power P2 that can be output from the second voltage converter 12 and the output power P3 that can be output from the auxiliary battery 7 is equal to or less than a predetermined value Pth. to decide. The output power P2 is a constant (for example, 1500 W) determined by the rating of the second voltage converter 12.
The output power P3 is calculated by the following method, for example. First, an integrated current is calculated using a current sensor provided in the auxiliary battery 7, a charging rate of the auxiliary battery 7 is calculated based on the integrated current, and an open circuit voltage (Vovv) is calculated based on the charging rate. presume. Next, the internal resistance (Rh) of the auxiliary battery 7 is estimated based on the current sensor and the detected value of the voltage sensor provided in the auxiliary battery 7. In this case, the current value Ih that can be output from the auxiliary battery 7 is expressed by the following equation.
Ih = (Vocv−Vth) / Rh
Vth is a driving voltage of the low-voltage device. The system controller 29 can calculate the output power P3 by the following equation.
P3 = Ih × Vth = Vth × (Vocv−Vth) / Rh
The predetermined value Pth is the total driving power (for example, 300 W) for driving the high-order devices 8 and 29. If the system controller 29 determines YES in S30, the system controller 29 proceeds to S70 and turns off the switch 14. On the other hand, if the system controller 29 determines NO in S30, it returns to S20.

  In S <b> 70, the system controller 29 opens the switch 14 to stop the operation of the low-order device 31 and continue the operation of the high-order devices 8 and 29. When S70 ends, the process of FIG. 2 ends.

  In S <b> 40, the system controller 29 determines whether an abnormality has occurred in the second voltage converter 12. The determination method of S40 is the same as the determination method of S10 described above. If the system controller 29 determines YES in S40, the system controller 29 proceeds to S50. On the other hand, if the system controller 29 determines NO in S40, it returns to S10.

  In S50, the system controller 29 stops the operation of the second voltage converter 12 and continues the operation of the first voltage converter 11. In this case, power is supplied from the main battery 3 to the high-order devices 8 and 29 via the first voltage converter 11 and also from the auxiliary battery 7. The low-order equipment 31 is supplied with power from the main battery 3 via the first voltage converter 11 and also with power from the auxiliary battery 7.

  In S60, the system controller 29 determines whether or not the total output power obtained by summing the output power P1 that can be output from the first voltage converter 11 and the output power P3 that can be output from the auxiliary battery 7 is equal to or less than a predetermined value Pth. to decide. The output power P1 is a constant (for example, 1500 W) determined by the rating of the first voltage converter 11. If the system controller 29 determines YES in S60, it proceeds to S70 and turns off the switch 14. On the other hand, if the system controller 29 determines NO in S60, it returns to S50.

  The hybrid vehicle 2 of the present embodiment stops the voltage converter in which an abnormality has occurred (S20, S50), and the output power that can be output by the voltage converter that continues to operate and the output power P3 that the auxiliary battery 7 can output. It is determined whether or not the total output power obtained by summing up and below is a predetermined value Pth or less (S30, S60). When the hybrid vehicle 2 determines that the total output power is equal to or less than the predetermined value Pth (YES in S30, YES in S60), the operation of the low-order device 31 is stopped and the operation of the high-order devices 8 and 29 is continued. (S70). In this case, the state shifts from the state in which the total output power is supplied to both the high-order devices 8 and 29 and the low-order device 31 to the state in which the total output power is supplied only to the high-order devices 8 and 29. As the state shifts, the operable period of the high-order devices 8 and 29 is extended. As a result, the electric vehicle can continue running for a long time.

(Second embodiment)
The difference between the hybrid vehicle 102 of the second embodiment and the first embodiment will be described with reference to FIG. In the present embodiment, the first auxiliary power line 21 is connected to the second auxiliary power line 22 via the fourth auxiliary power line 24. A switch 25 is connected in the middle of the fourth auxiliary machine power line 24.

  The system controller 29 controls the opening and closing of the switch 25. Normally, the system controller 29 opens the switch 25. In this case, power is not supplied to the low-order device 31 and the low-voltage battery 7 via the second voltage converter 12. The system controller 29 closes the switch 25 when the driver performs a predetermined operation. In this case, electric power is supplied to the low-order device 31 via the second voltage converter 12. Also in this embodiment, the electric vehicle can continue running for a long time by executing the processing of FIG.

  The technology disclosed in this specification may be applied to an electric motor vehicle that does not include an engine. The electric vehicle referred to in this specification includes a hybrid vehicle including an engine and a traveling motor, and an electric vehicle including a motor but not an engine. The electric vehicle referred to in this specification includes a fuel cell as a main power source for driving a traveling motor, and a battery that stores electric power (regenerative power) generated by the traveling motor using deceleration energy. Includes onboard vehicles.

  The voltage converters 11 and 12 of the above embodiment are unidirectional converters that perform only a step-down operation for stepping down the output voltage of the main battery 3. In a modification, the voltage converters 11 and 12 may be bidirectional converters that perform a step-down operation and a step-up operation that steps up the output voltage of the auxiliary battery 7.

  Instead of the diodes 9a and 9b connected to the auxiliary power lines 22 and 23, diodes may be provided at the input terminals 8a and 29a of the high-order devices 8 and 29, respectively.

  In S <b> 70 of FIG. 2, the system controller 29 may stop the operation of the low-order equipment 31 instead of the system controller 29 opening the switch 14. In this case, the switch 14 becomes unnecessary.

Instead of using the two diodes 9a and 9b, a single diode may be used. The low voltage wirings 22 and 23 in FIG. 2 may be connected, and the anode of the diode may be connected to the connection point.
In this case, when the voltage converters 11 and 12 are normal, the power from the voltage converters 11 and 12 and the power from the auxiliary battery 7 are supplied to the high-order devices 8 and 29 and the low-order device 31. Even in this case, the electric vehicle can continue running for a long time by executing the processing of FIG.

There may be the following modifications in which the hybrid vehicle 2 includes only one voltage converter. In the modification, the first voltage converter 11 and the diode 9a shown in FIG. 1 are omitted. In the modification, power is supplied from the main battery 3 to the high-order devices 8 and 29 and the low-order device 31 via the second voltage converter 12.
In the present modification, the system controller 29 executes the following processing. The system controller 29 determines whether an abnormality has occurred in the second voltage converter 12 and the output power has decreased. When the system controller 29 determines that an abnormality has occurred in the second voltage converter 12, the total sum of the output power P2 that can be output from the second voltage converter 12 and the output power P3 that can be output from the auxiliary battery 7 It is determined whether or not the output power is less than or equal to a predetermined value Pth. When the system controller 29 determines that the total output power is equal to or less than the predetermined value Pth, the system controller 29 stops the operation of the low-order device 31 and continues the operation of the high-order devices 8 and 29. This modification also has the effect that the electric vehicle can continue traveling for a long time.

In the above embodiment, the embodiment of the electric vehicle is the hybrid vehicle 2, the embodiment of the high voltage battery is the main battery 3, the embodiment of the high voltage wiring is the main power line 28 (precisely its positive line), An example of the low voltage battery is the auxiliary battery 7, an example of the low voltage wiring is the auxiliary power lines 21, 22, 23, and 24, an example of the first voltage converter is the first voltage converter 11, and The embodiment of the two-voltage converter is the second voltage converter 12, the embodiment of the high-order device is the shift-by-wire device 8 and the system controller 29, the embodiment of the low-order device is the air conditioner device, and the implementation of the control device An example is the system controller 29. The system controller 29 when executing S10 and S20 and S40 and S50 in FIG. 2 is an embodiment of the voltage converter abnormality processing means, and the system controller 29 when executing S30 and S70 and S40 and S70 in FIG. Is an embodiment of the priority processing means.
Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Hybrid vehicle 3: Main battery 4: System main relay 5: Power converter 6: Motor 7: Auxiliary battery 8: Shift-by-wire device 8a: Power input terminals 9a, 9b: Diode 11: First voltage converter 12: First 2 voltage converters 14 and 25: switch 21: first auxiliary power line 22: second auxiliary power line 23: third auxiliary power line 24: fourth auxiliary power line 28: main power line 29: system controller 31: air conditioner 91: Engine 92: Transmission 93: Axle

Claims (1)

A high voltage battery;
High-voltage wiring to which the voltage of the high-voltage battery is applied;
A low voltage battery;
Low voltage wiring to which the voltage of the low voltage battery is applied;
A first voltage converter and a second voltage converter connected in parallel between the high-voltage wiring and the low-voltage wiring;
High-order equipment and low-order equipment connected in parallel to the low-voltage wiring,
An electric vehicle equipped with a control device;
The control device is
Voltage converter abnormality that stops the operation of the abnormal voltage converter and continues the operation of the normal voltage converter when an abnormality occurs in one of the first voltage converter and the second voltage converter Voltage converter abnormality processing means for executing time processing;
When the total output power that is the sum of the power that can be output from the voltage converter that continues to operate and the power that can be output from the low-voltage battery is equal to or lower than the drive power that drives the high-order device, the low-order An electric vehicle comprising priority processing means for executing priority processing for stopping operation of a device and continuing operation of the high-order device.

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