JP2018027733A - Charge controller of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge controller of a hybrid vehicle, which enables charge of a battery even upon failure of a power generation control circuit of a generator, thus allowing normal running performance to be maintained.SOLUTION: When a motor generator 11 is required to generate power during failure of an electronic control unit (ECU) 24 for a front motor, or an inverter 17, each for controlling the motor generator 11, rotational speed of an idling engine 3 is increased, causing the motor generator 11, which is directly connected with the engine 3, to generate an induced voltage. When the induced voltage exceeds a battery voltage (a voltage of a run battery 20) or a voltage after boosted by a voltage boost converter 18, a charge current is generated, thus the run battery 20 is charged. After completion of the charge, dropping the rotational speed of the engine 3 and the motor generator 11 reduces the induced voltage, and the charge is stopped when the induced voltage becomes equal to or under the battery voltage or the voltage after boosted.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a charge control device for a hybrid vehicle, and more particularly to a charge control device that can charge a traveling battery when a power generation control device of a generator fails.

  In this type of hybrid vehicle, various measures are taken in preparation for a failure of the electric system. For example, if the generator power generation control circuit breaks down, the generator cannot be controlled to generate power, so series travel by driving the travel motor using the power generated by the generator, or parallel travel using the drive power of the engine in addition to the travel motor, etc. Cannot be executed. For this reason, the travel mode of the vehicle is limited to only EV travel that travels only with the discharge power from the travel battery, and the cruising distance depends on the SOC (State Of Charge) of the travel battery at the time of failure. When the traveling battery is completely discharged, it becomes impossible to travel.

  As a countermeasure for such a failure, for example, the technique of Patent Document 1 can be cited. In the technology of Patent Document 1, when the generator becomes uncontrollable due to a failure such as a running battery or an inverter, the generator is driven while performing feedback control of the engine at the target rotational speed, and the reverse generated in the generator. By using the electromotive force to drive the traveling motor, it is possible to travel to the nearest service station etc. at the limp home.

JP 2003-204606 A

However, since the technique described in Patent Document 1 is a measure against sudden changes on the premise of limp home, even though it is a series running, the running performance is limited and it is not suitable for a long running. As a result, there was a problem that normal running performance could not be maintained after the failure occurred.
The present invention has been made to solve such problems, and the object of the present invention is to make it possible to charge a battery even when a generator control circuit of a generator fails, thereby maintaining normal running performance. An object of the present invention is to provide a charge control device for a hybrid vehicle.

  In order to achieve the above object, a charging control device for a hybrid vehicle according to the present invention controls a permanent magnet generator driven by an engine by a power generation control means, and uses the power generated by the generator to In a hybrid vehicle for driving and charging a running battery, a failure determination unit that determines a failure of the power generation control unit, and the power generation control unit when the failure determination unit determines that a failure has occurred in the power generation control unit And an induced voltage charging control means for charging the traveling battery by generating an induced voltage in the generator by driving the generator with the engine in a state without control by Item 1).

  According to the charging control device for a hybrid vehicle configured as described above, the generator is driven by the engine when the power generation control unit fails, and the traveling battery is charged using the induced voltage generated in the generator. At this time, if the vehicle is traveling by driving the traveling motor, it can be regarded as a substantial series traveling, so that it is possible to perform the series traveling while maintaining normal traveling performance, and after switching to parallel traveling, EV traveling, etc. Even normal driving performance can be maintained.

As another aspect, when the induced voltage charge control means determines that the power generation control means has failed and there is a power generation request to the generator, the generator is rotated and raised together with the engine. It is preferable that the traveling battery is charged by controlling so that the induced voltage generated by exceeds the voltage of the traveling battery.
According to this aspect, when a failure occurs in the power generation control means and when there is a power generation request, the generator and the engine rotate up and an induced voltage is generated. Then, when the induced voltage exceeds the voltage of the traveling battery, or when the boosting means for boosting the voltage of the traveling battery is provided, the charging current to the traveling battery is increased when the induced voltage exceeds the boosted voltage. Generated and charged.

  As another aspect, the apparatus further includes a boosting unit that arbitrarily boosts the voltage of the traveling battery and supplies the voltage to the traveling motor, and when the induced voltage charging control unit determines that a failure has occurred in the power generation control unit, The generator is rotated and raised together with the engine so that the induced voltage generated by the generator exceeds the voltage of the traveling battery, and when there is no power generation request to the generator, The charging of the traveling battery is stopped by controlling the voltage to be equal to or higher than the induced voltage, and when the power generation is requested, the traveling battery is charged by controlling the boosted voltage to be lower than the induced voltage. (Claim 3).

According to this aspect, when a failure occurs in the power generation control means, the generator rotates with the engine and an induced voltage exceeding the voltage of the traveling battery is generated. When there is no power generation request, the boosted voltage is controlled to be higher than the induced voltage and charging of the traveling battery is stopped. When there is a power generation request, the boosted voltage is controlled to be lower than the induced voltage and the traveling battery is charged. Is done.
In another aspect, the apparatus further includes a boosting unit that boosts the discharged power of the traveling battery and supplies the boosted electric power to the traveling motor, and the induced voltage charging control unit is at least when it is determined that a failure has occurred in the power generation control unit. The driving mode of the vehicle is switched to driving using the engine using the engine, and the power generation is performed in an operating region where the induced voltage generated by the generator exceeds the voltage of the traveling battery due to the increase in rotation of the engine according to the vehicle speed. When there is no power generation request to the machine, charging of the traveling battery is stopped by controlling the boosted voltage of the boosting unit to be equal to or higher than the induced voltage, and when there is a power generation request, the charging voltage is lower than the induced voltage. It is preferable to charge the traveling battery by controlling the boosted voltage.

  According to this aspect, when a failure occurs in the power generation control means, the travel mode of the vehicle is switched to travel using the engine, and when there is no power generation request in the operation region where the induced voltage of the generator exceeds the voltage of the travel battery, The boosted voltage is controlled to be equal to or higher than the induced voltage and charging of the running battery is stopped. When there is a power generation request, the boosted voltage is controlled to be lower than the induced voltage and the running battery is charged.

As another aspect, when the induced voltage of the generator driven by the engine is outside a preset normal range, it is considered that the generator itself has failed, and the traveling battery is charged by the induced voltage charging control means. It is preferable to further include a first charging control prohibiting unit that prohibits charging.
According to this aspect, when the failure of the generator itself occurs, the traveling battery cannot be charged. In such a case, charging of the traveling battery is prohibited, and therefore, unnecessary fuel consumption due to an increase in engine rotation is suppressed. It becomes possible.

As another aspect, the battery pack further includes second charge control prohibiting means for prohibiting charging of the travel battery by the induced voltage charge control means when the charge rate of the travel battery is equal to or higher than a preset charge prohibition determination value. (Claim 6).
According to this aspect, if charging using the induced voltage of the generator is performed near the full charge of the traveling battery, overcharging may occur, but such a situation is prevented.

  According to the hybrid vehicle charging control apparatus of the present invention, it is possible to charge the battery even when the generator power generation control circuit is out of order, thereby maintaining normal running performance.

1 is an overall configuration diagram illustrating a plug-in hybrid vehicle to which a charge control device of an embodiment is applied. It is a flowchart which shows the induced voltage charge routine which vehicle ECU of 1st Embodiment performs. FIG. 6 is a characteristic diagram showing a switching state between charging ON and charging OFF when an induced voltage is increased or decreased by a rotation change of a motor generator. It is a time chart which shows the execution situation of induction voltage charge control by vehicle ECU of a 1st embodiment. FIG. 6 is a characteristic diagram showing a switching state between charging ON and charging OFF when the boosted voltage is increased or decreased by the boost converter. It is a flowchart which shows the induced voltage charge routine which vehicle ECU of the modification of 1st Embodiment performs. It is a flowchart which shows the induced voltage charge routine which vehicle ECU of 2nd Embodiment performs.

Hereinafter, an embodiment in which the present invention is embodied in a charge control device for a plug-in hybrid vehicle (hereinafter referred to as a vehicle 1) will be described.
FIG. 1 is an overall configuration diagram showing a plug-in hybrid vehicle to which the charge control device of this embodiment is applied.
The vehicle 1 of this embodiment is a four-wheel drive vehicle configured to drive the front wheels 4 by the output of the front motor 2 or the outputs of the front motor 2 and the engine 3 and to drive the rear wheels 6 by the output of the rear motor 5. is there.

  The output shaft of the front motor 2 is connected to the drive shaft 7 of the front wheel 4, and the engine 3 is connected to the drive shaft 7 through a clutch 8. The front wheel is connected to the drive shaft 7 through a front differential 9 and left and right drive shafts 10. 4 are connected. The driving force of the front motor 2 and the driving force of the engine 3 when the clutch 8 is connected are transmitted to the front wheels 4 through the driving shaft 7, the front differential 9 and the left and right driving shafts 10, and the front wheels 4 are driven for vehicle travel. The driving force is generated. A permanent magnet type motor generator 11 (generator) is connected to the output shaft of the engine 3, and the motor generator 11 can arbitrarily generate power by driving the engine 3 regardless of whether the clutch 8 is connected or disconnected. It also functions as a starter for starting the stopped engine 3 at the time of disconnection.

On the other hand, the output shaft of the rear motor 5 is connected to the drive shaft 12 of the rear wheel 6, and the rear wheel 6 is connected to the drive shaft 12 via the rear differential 13 and the left and right drive shafts 14. The driving force of the rear motor 5 is transmitted to the rear wheel 6 through the driving shaft 12, the rear differential 13 and the left and right driving shafts 14, and the driving force for driving the vehicle is generated in the rear wheel 6.
Inverters 16 and 17 are connected to the front motor 2 and the motor generator 11, respectively, and these inverters 16 and 17 are connected to a boost converter 18 (boost means). An inverter 19 is connected to the rear motor 5, and the inverter 19 and the traveling battery 20 are connected to a boost converter 18. The traveling battery 20 is composed of a secondary battery such as a lithium ion battery, and incorporates a battery monitoring unit 20a for calculating the SOC (charge rate) and detecting the temperature TBAT.

  The operation voltage is different between the rear side and the front side with the boost converter 18 as a boundary, and the rear motor 5 and the inverter 19 are manufactured to a specification that operates by the voltage of the traveling battery 20 (for example, 300V), and the low voltage circuit together with the traveling battery 20 21, the front motor 2, the motor generator 11 and their inverters 16, 17 are manufactured to a specification that operates at a higher voltage (for example, 600 V) for the purpose of improving efficiency, and constitutes a high voltage circuit 22. Yes.

  The step-up converter 18 functions to step up and step down when power is exchanged between both the circuits 21 and 22. For example, the low-voltage side DC power discharged from the traveling battery 20 is boosted and supplied to the inverter 16, and the front motor 2 is driven by the three-phase AC power converted by the inverter 16 and is also converted by the inverter 17. The motor generator 11 functions as a starter by the three-phase AC power. The three-phase AC power generated by the motor generator 11 is converted into high-voltage DC power by the inverter 17, and the DC power is stepped down by the boost converter 18 to charge the traveling battery 20, and the voltage is stepped down by the boost converter 18. The direct-current power thus converted is converted into three-phase alternating-current power by the inverter 19, and the rear motor 5 is driven by receiving the supply.

  Note that power exchange in the same circuits 21 and 22 is performed without going through the boost converter 18. For example, on the low-voltage circuit 21 side, the DC power discharged from the traveling battery 20 is supplied to the rear motor 5 after being converted into three-phase AC power by the inverter 19, and conversely, the three-phase AC power generated by the rear motor 5 by regenerative control is The traveling battery 20 is charged by being converted into DC power by the inverter 19. On the high voltage circuit 22 side, the three-phase AC power generated by the motor generator 11 is converted into DC power by the inverter 17, and then converted again to three-phase AC power by the inverter 16 and supplied to the front motor 2.

  A front motor ECU 24 is connected to the inverters 16 and 17 on the high voltage circuit 22 side, and the inverters 16 and 17 are switched by the front motor ECU 24 to control the operating states of the front motor 2 and the motor generator 11 as described above. Is done. In the present embodiment, the front motor ECU 24 and the inverter 17 that control the motor generator 11 function as power generation control means of the present invention.

In addition, a rear motor ECU 25 is connected to the inverter 19 on the low voltage circuit 21 side, and the inverter 19 is switched by the rear motor ECU 25 to control the operating state of the rear motor 5 as described above.
An engine ECU 26 is connected to the engine 3, and the engine ECU 26 is operated by controlling the throttle opening, fuel injection amount, ignition timing, and the like of the engine 3.

Although not shown, the traveling battery 20 includes a charger, and the traveling battery 20 can be arbitrarily charged with electric power supplied from an external power source using the charger.
The front motor ECU 24, the rear motor ECU 25, and the engine ECU 26 described above are connected to a vehicle ECU 27 corresponding to a host unit. Each of the ECUs 24 to 27 includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), It consists of a central processing unit (CPU) and the like.

  The vehicle ECU 27 is a control unit for performing comprehensive control of the vehicle 1, and the front motor 2, the motor generator 11, the rear motor as described above are executed by the lower ECUs 24 to 26 that receive a command from the vehicle ECU 27. 5. Each operation state of the engine 3 is controlled. Therefore, sensors such as a battery monitoring unit 20a of the traveling battery 20 and an accelerator opening sensor that detects an accelerator opening (not shown) and a vehicle speed sensor that detects the vehicle speed V are connected to the input side of the vehicle ECU 27. The operating states of the front motor 2, the motor generator 11, the rear motor 5, and the engine 3 are input via the ECUs 24 to 26.

In addition to the front motor ECU 24, the rear motor ECU 25, and the engine ECU 26 described above, the clutch 8 and the boost converter 18 are connected to the output side of the vehicle ECU 27.
Then, the vehicle ECU 27 switches the travel mode of the vehicle 1 between EV travel, series travel, and parallel travel based on the various detection amounts and operation information such as the accelerator opening sensor. For example, in a region where the efficiency of the engine 3 is high, such as a high-speed region, the traveling mode is set to parallel traveling. In the middle / low speed range, switching between EV traveling and series traveling is performed based on the SOC of the traveling battery 20 or the like.

  In the EV traveling, the clutch 8 is disconnected and the engine 3 is stopped. The front motor 4 is driven by the electric power from the traveling battery 20 and the rear wheel 6 is driven by the rear motor 5 to drive the vehicle 1. In the series running, the clutch 8 is disconnected and the engine 3 is disconnected from the front wheel 4 side, then the engine 3 is operated to drive the motor generator 11, and the power generation is controlled by the front motor ECU 24 and the inverter 17. Thus, the front motor 2 drives the front wheels 4 and the rear motor 5 drives the rear wheels 6 to run the vehicle 1 and charge the running battery 20 with surplus power.

  In parallel travel, the clutch 8 is connected and the engine 3 is operated to transmit the driving force to the front wheels 4. When the engine driving force is insufficient, the front motor 2 and the rear motor 5 are driven using battery power. When the traveling battery 20 needs to be charged due to a decrease in the SOC, the motor generator 11 driven by the driving force of the engine 3 is controlled by the front motor ECU 24 and the inverter 17 to generate power, and the generated power is The traveling battery 20 is charged.

Of course, when the power is exchanged between the high-voltage and low-voltage circuits 21 and 22, the voltage is boosted and lowered by the boost converter 18 as described above.
Further, the vehicle ECU 27 calculates a total required output necessary for traveling of the vehicle 1 based on the various detection amounts and operation information, and outputs the total required output for the front motor 2 side and the rear motor 5 side in EV traveling and series traveling. And distributed to the front motor 2 side, the engine 3 side, and the rear motor 5 side in parallel running. Then, based on the required outputs allocated to each, the required torques of the front motor 2, the rear motor 5 and the engine 3 are set, and command signals are sent to the front motor ECU 24, the rear motor ECU 25 and the engine ECU 26 so as to achieve the required torques. Is output.

  The front motor ECU 24 and the rear motor ECU 25 calculate a target current value to be passed through the coils of the respective phases of the front motor 2 and the rear motor 5 in order to achieve the required torque based on a command signal from the vehicle ECU 27. The inverters 16 and 19 are switched based on the target current values to achieve the required torque. The same is true when the motor generator 11 generates power, and the front motor ECU 24 achieves the required torque by switching the inverter 17 based on the target current value obtained from the negative required torque.

Based on a command signal from the vehicle ECU 27, the engine ECU 26 calculates target values such as a throttle opening, a fuel injection amount, an ignition timing, etc. for achieving the required torque, and operates the engine 3 by control based on those target values. To achieve the required torque.
On the other hand, the vehicle ECU 27 controls the step-up converter 18 to step up and step down the electric power exchanged between the high and low voltage circuits 21 and 22.

  By the way, as described in [Problems to be Solved by the Invention], when a connection portion (harness or the like) from the front motor ECU 24 that controls the motor generator 11 to the inverter 17 or the inverter 17 breaks down, the traveling mode is only EV traveling. In addition, if the front motor ECU 24 fails, the drive control of the front motor 2 cannot be performed. Therefore, there is a problem that the cruising distance is reduced only by the EV traveling by driving only the rear motor 5. When the motor generator 11 is controlled by an ECU different from the front motor ECU 24, even if the other ECU fails, the front motor ECU 24 does not interfere with the drive control of the front motor 2.

The technique of Patent Document 1 that drives the traveling motor by the counter electromotive force obtained by driving the generator with the engine has a problem that the traveling performance is limited because of limp home, so that normal traveling cannot be maintained. It was.
As a countermeasure, in the present embodiment, control for charging the traveling battery (hereinafter referred to as induced voltage charging control) is performed using the induced voltage of the motor generator 11, and the induced voltage charging performed by the vehicle ECU 27 is hereinafter performed. Control will be described as first and second embodiments.
[First Embodiment]
FIG. 2 is a flowchart showing an induced voltage charging routine executed by the vehicle ECU 27 of the first embodiment.

  The front motor ECU 24 constantly monitors its own failure and the failure of the inverter 17 and outputs failure information to the vehicle ECU 27 when it is determined that a failure has occurred (failure determination means). When such failure information is input, the vehicle ECU 27 executes the routine of FIG. 2 at a predetermined control interval as the induced voltage charging control. The vehicle ECU 27 when executing this routine functions as the induced voltage charge control means of the present invention.

  In the induced voltage charging control, since the motor generator 11 is rotated and raised by driving the engine 3, the engine 3 needs to be operating at the time of failure determination. This is because after the failure, the motor generator 11 functions as a starter and the engine cannot be started. Therefore, the routine of FIG. 2 is executed on the condition that the engine is operating. However, unlike the present embodiment, when the engine 3 includes a dedicated starter device, the routine may be executed even when the engine is stopped.

  When the vehicle ECU 27 starts the routine of FIG. 2, first, in step S <b> 1, it is determined whether or not there is a power generation request for the motor generator 11. If it is not necessary to charge the traveling battery 20, it is determined that there is no power generation request, and a determination of No (No) is made in step S1, and the routine is temporarily terminated. Further, when the traveling battery 20 needs to be charged, it is determined that there is a power generation request, a Yes (positive) determination is made in step S1, and the process proceeds to step S2. In step S2, it is determined whether or not the SOC of the traveling battery 20 is less than a preset charge prohibition determination value, and when it is No, the routine is terminated.

  The normal front motor ECU 24 finely controls the induced voltage to prevent overtravel of the traveling battery 20 due to the induced voltage generated in the motor generator 11. In the induced voltage charging control, since the induced voltage is generated by the rotation increase of the motor generator 11 in a state without the control by the front motor ECU 24 and the inverter 17, it must be said that the control is rough compared to the normal state. For this reason, if the induced voltage charge control is executed near the full charge of the traveling battery 20, overcharge may occur. To prevent such a situation, the induced voltage charge control is performed when the SOC is equal to or higher than the charge prohibition determination value. It is prohibited (second charge control prohibiting means).

When the determination in step S3 is Yes, it is determined that the induced voltage charge control can be executed, and the process proceeds to step S3. In step S3, a command signal is output to the engine ECU 26 to increase the engine rotational speed Ne during idle operation.
FIG. 3 is a characteristic diagram showing a switching state of presence / absence of charging (hereinafter also referred to as charging ON / charging OFF) when the induced voltage is increased / decreased by the rotation change of the motor generator 11. The rotational speed Ng of the motor generator 11 directly connected to the engine 3 increases with the engine rotational speed Ne, and the permanent magnet motor generator 11 generates an induced voltage substantially proportional to the rotational speed Ng. Therefore, the induced voltage gradually increases as the motor generator 11 rotates.

In the subsequent step S4, it is determined whether or not the induced voltage is within a preset normal range. More specifically, the normal induced voltage of the motor generator 11 is set in advance as a normal range for each rotation range of the motor generator 11, and the induced voltage enters the normal range corresponding to the current rotational speed Ng. It is determined whether or not.
As described above, the induced voltage charging control is started based on the occurrence of a failure in the front motor ECU 24 or the inverter 17, but an actual failure may occur in the motor generator 11 itself. For example, when all phases of the windings of the motor generator 11 are disconnected, no induced voltage is generated and the traveling battery 20 cannot be charged, so there is no merit of performing induced voltage charging control. Since there is a predetermined correlation between the rotational speed Ng of the motor generator 11 and the induced voltage, if the correlation is not recognized (the induced voltage is outside the normal range), it is regarded as a failure of the motor generator 11 itself, and step S4 In step S8, the determination of No is made. In step S8, the engine speed Ne is decreased to return the engine 3 to idle operation, and then the routine is terminated. Accordingly, in this case, the induced voltage charge control is not substantially executed, and the EV mode is continued as the travel mode by the normal control (first charge control prohibiting means). Thereby, useless fuel consumption resulting from the rotation increase of the engine 3 at the time of induced voltage charge control can be suppressed.

  Further, when the induced voltage is within the normal range and the determination of Yes is made in step S4, it is determined in step S5 whether or not the charging current to the traveling battery 20 has reached the target current. Return to. The target current is sequentially set based on the SOC, voltage, temperature, and the like of the traveling battery 20, and is gradually changed to a lower side as the SOC increases due to charging, for example.

  The charging current to the traveling battery 20 is basically generated when the induced voltage of the motor generator 11 exceeds the voltage of the traveling battery 20 (hereinafter referred to as the battery voltage), and the charging current increases as the induced voltage increases. . Charging of the traveling battery 20 is started from the time when the charging current is generated, and in the example of FIG. 3, the rotational speed Ng (less than the rotational speed Ng0 with the rotational speed Ng0 of the motor generator 11 when the induced voltage = battery voltage as a boundary. For example, it is not charged at NgLo), and charged at a rotational speed Ng (for example, Ng Hi) exceeding the rotational speed Ng0, and the charging current gradually increases as the rotation speed increases.

  However, in this embodiment, since the battery voltage is boosted by the boost converter 18 (hereinafter referred to as a boosted voltage), a charging current is generated when the induced voltage exceeds the boosted voltage. In the following description, for the sake of convenience, it is assumed that the discharge power of the traveling battery 20 is supplied to the front motor 2 without being converted into a voltage by stopping the function of the boost converter 18 (voltage after boosting = battery voltage). When the converter 18 has a boosting function, the boosted voltage is used as an index instead of the battery voltage.

  Each time the process of step S3 is repeated, the induced voltage increases with the rotational speed Ng of the motor generator 11, and the charging current increases accordingly, reaching the target current at any point. The vehicle ECU 27 makes a determination of Yes in step S5, proceeds to step S6, and maintains the engine speed Ne of the previous value (at the previous control interval). In the subsequent step S7, it is determined whether or not the SOC of the traveling battery 20 has reached the target SOC, and the process of step S6 is repeated for No to maintain the engine speed Ne. If the determination in step S7 is Yes, the routine proceeds to step S8 and the routine is ended after the engine 3 is returned to idle operation.

Next, the execution status of the induced voltage charging control by the vehicle ECU 27 will be described with reference to the time chart of FIG.
When failure information is input from the front motor ECU 24 and a power generation request is made thereafter, the motor generator 11 starts to rotate with the engine 3 on the condition that there is no possibility of overcharging and that the motor generator 11 itself is not broken. (Point a in FIG. 4). As the rotation increases, the induced voltage of the motor generator 11 increases, and when the induced voltage reaches the battery voltage (point b), a charging current is generated and the traveling battery 20 starts to be charged. At this time, the vehicle 1 is traveling by driving the front and rear motors 2 and 5 while charging the traveling battery 20 with the electric power generated by the motor generator 11 and can be regarded as being substantially traveling in series. Of course, since the induced voltage charging control can be executed regardless of the running state of the vehicle 1, charging while the vehicle is stopped is also possible.

  When the charging current gradually increases and reaches the target current (point c), the rotational speed Ng of the engine 3 and the motor generator 11 at that time is held. By continuing this state, the SOC of the traveling battery 20 gradually increases, and when the SOC reaches the target SOC, the engine 3 and the motor generator 11 start to decrease in rotation (point d). For this reason, the charging current is lowered together with the induced voltage, the engine 3 is returned to the idle operation, and the induced voltage and the charging current are returned to the state before the power generation request.

  As described above, in the charging control device for the hybrid vehicle 1 of the present embodiment, the motor generator 11 is driven by the engine 3 when the front motor ECU 24 or the inverter 17 fails, and the battery voltage (or the boosted voltage) is supplied to the motor generator 11. The traveling battery 20 is charged by generating an induced voltage exceeding. Although charging of the traveling battery 20 at this time is not efficient as compared with normal charging control, the charging current increases with the induced voltage as the rotation of the motor generator 11 increases. Charging with a suitable target current is possible, and thus the SOC of the traveling battery 20 can be recovered to the target SOC.

For this reason, during the execution of the induced voltage charging control, it is possible to perform series traveling while maintaining normal traveling performance, and it is possible to maintain normal traveling performance even after switching to parallel traveling or EV traveling.
By the way, when the induced voltage charging control of the present embodiment is simply expressed, the induced voltage is increased or decreased by the rotation change of the motor generator 11 on the basis of the battery voltage (or the boosted voltage), and the traveling is performed when the induced voltage exceeds the battery voltage. The battery 20 is charged, and the charging is stopped when the battery voltage is lower than the battery voltage. However, since the boosted voltage can be arbitrarily changed in the present embodiment including the boost converter 18, the boosted voltage is increased / decreased by the boost converter 18 on the basis of the induced voltage, and the boosted voltage is reversed. The battery 20 can be charged when is below the induced voltage, and can be stopped when the boosted voltage exceeds the induced voltage.

Hereinafter, the induced voltage charge control based on this idea will be described as a modification of the first embodiment.
FIG. 5 is a characteristic diagram showing a switching state between charge ON and charge OFF when the boosted voltage is increased or decreased by the boost converter 18.
The lower limit of the boosted voltage by the boost converter 18 is the battery voltage, and the upper limit is an eigenvalue corresponding to the specification of the boost converter 18, and the boosted voltage can be arbitrarily adjusted within the range. The charging current to the traveling battery 20 is generated when the boosted voltage falls below the induced voltage of the motor generator 11, and the charging current increases as the boosted voltage decreases. Therefore, it is necessary to control the motor generator 11 in advance at a rotational speed Ng at which an induced voltage higher than the battery voltage, which is the lower limit of the adjustment range, can be obtained in order to ensure a decrease range of the boosted voltage. Since it is desirable to secure the target current as the charging current, for example, an induced voltage obtained by adding a voltage width corresponding to the target current to the battery voltage (hereinafter referred to as a reference induced voltage) is set, and the rotation speed at which this reference induced voltage is obtained The motor generator 11 is controlled to Ng0.

With such a reference induced voltage as a boundary, charging is stopped when the boosted voltage is higher than the reference induced voltage, charged when the boosted voltage is lower than the induced voltage, and maximum when the boosted voltage drops to the battery voltage. A charging current (= target current) is obtained. Of course, the reference induced voltage may be set to a larger value in consideration of the margin.
FIG. 6 is a flowchart showing an induced voltage charging routine executed by the vehicle ECU 27 according to the modification.

  If there is a power generation request in step S1 and the SOC is less than the charge prohibition determination value in step S2, the motor generator 11 is rotated together with the engine 3 in step S3. In step S4, after confirming that the induced voltage is within the normal range, it is determined in step S11 whether the induced voltage has reached the reference induced voltage. When the determination in step S11 is Yes due to the increase in rotation, the rotation is held in step S6, and in the subsequent step S12, the boosted voltage is controlled to a value (for example, battery voltage) that is reduced by the target current from the reference induced voltage. As a result, the traveling battery 20 is charged with the target current. When the SOC of the traveling battery 20 reaches the target SOC in step S7, the engine 3 is returned to the idle operation in step S8, and the boosted voltage is returned to the original value in the subsequent step S13. After returning, the routine ends.

Also in the above modification, the traveling battery 20 can be charged using the induced voltage generated in the motor generator 11 when the front motor ECU 24 or the inverter 17 fails. Therefore, although not redundantly described, the same effects as those of the above embodiment can be obtained.
On the other hand, in this modification, the engine 3 is idled during normal operation and the motor-generator 11 is rotated together with the engine 3 to generate the reference induced voltage every time a power generation request is made. However, the present invention is not limited to this. For example, after the occurrence of a failure, the motor generator 11 may be kept at the rotational speed Ng0 at which the reference induced voltage is always obtained. In this case, charging ON / OFF of the traveling battery 20 is executed by switching the boosted voltage by the boost converter 18. That is, when there is no power generation request, charging the running battery 20 is stopped by controlling the boosted voltage to be higher than the reference induced voltage, and when there is a power generation request, the boosted voltage is controlled to be lower than the reference induced voltage. Thus, the traveling battery 20 is charged.

Since the rotation control of the engine 3 of the modification is accompanied by a physical change, the control response of charge ON / charge OFF is not so good, but the control of the boosted voltage by the boost converter 18 is good because of the electrical change. Control responsiveness is obtained. Therefore, charging can be quickly turned ON / OFF depending on whether there is a power generation request, and even when a failure occurs, the traveling battery 20 can be held in a more appropriate SOC.
[Second Embodiment]
Next, a second embodiment in which the present invention is embodied in another charge control device will be described.

  The purpose of the induced voltage charge control of the present embodiment is to turn on / off the charge by increasing / decreasing the boosted voltage with the boost converter 18 using the induced voltage as a reference, as in the above-described modification. In this method, even if the induced voltage of the motor generator 11 changes with a change in the engine rotation speed Ne, it is arbitrarily charged if the induced voltage at that time is regarded as the reference induced voltage and the boosted voltage is controlled. This is one of the advantages that can be turned on and off and cannot be expected by the method of the first embodiment. Such a situation occurs in parallel traveling (engine traveling) in which the induced voltage of the motor generator 11 increases or decreases due to the rotation change of the engine 3 in accordance with the vehicle speed V. Therefore, this embodiment is applied to parallel traveling. It is.

  Therefore, in this embodiment, the boosted voltage is controlled by regarding the induced voltage of the motor generator 11 that constantly increases or decreases according to the vehicle speed V as the reference induced voltage. Since the lower limit of the boosted voltage is the battery voltage, in a region where the induced voltage of the motor generator 11 exceeds the battery voltage, even if the target current is not reached, a charging current is generated and the traveling battery 20 can be charged. For this reason, in this embodiment, the boosted voltage is controlled according to the charge request in a region exceeding the battery voltage. However, the present invention is not limited to this. For example, the boosted voltage may be controlled in a region equal to or larger than a value obtained by adding the target current to the battery voltage.

  FIG. 7 is a flowchart showing an induced voltage charging routine executed by the vehicle ECU 27 of the present embodiment. When failure information is input from the front motor ECU 24, the vehicle ECU 27 switches the traveling mode to parallel traveling, and induced voltage charging control. 7 is executed at a predetermined control interval. The vehicle ECU 27 when executing this routine functions as the induced voltage charge control means of the present invention.

  First, at step S21, it is determined whether or not the rotational speed Ng of the motor generator 11 exceeds the lower limit rotational speed Ng0, and when it is No, the routine is once terminated. Since the lower limit rotational speed Ng0 is the rotational speed Ng when the induced voltage of the motor generator 11 reaches the battery voltage, in the operating region when the condition of step S21 is satisfied, the induction of the motor generator 11 is caused by the increased rotation of the engine 3. It can be considered that the voltage exceeds the battery voltage and a charging current is generated in the motor generator 11.

  If the determination in step S21 is Yes, it is determined in step S22 whether or not there is a power generation request. If it is determined that there is no power generation request, the process proceeds to step S23. In step S23, the current induced voltage is regarded as a reference induced voltage, and after the boosted voltage is controlled to be higher than the reference induced voltage, the routine is terminated. Accordingly, the charging current to the traveling battery 20 is not generated, and the charging is turned off.

  Further, when it is determined Yes in step S22 that there is a power generation request, the process proceeds to step S24. In step S24, the current induced voltage is regarded as the reference induced voltage, and the boosted voltage is controlled to a value lower than the reference induced voltage by an amount equivalent to the target current. However, since it is impossible to control the boosted voltage below the battery voltage, for example, when the induced voltage is slightly higher than the battery voltage, the battery voltage is set as the lower limit of the boosted voltage control. Although the target current is not reached, a charging current is generated even in this case, so the traveling battery 20 is charged.

In this routine, the process of step S2 assuming overcharge of the traveling battery 20 based on FIG. 2 of the first embodiment and the process of step S4 assuming failure of the motor generator 11 itself are omitted. These processes may be added.
As described above, as long as the rotational speed Ng of the motor generator 11 is equal to or higher than the lower limit rotational speed Ng0 and a power generation request is made, the charging of the traveling battery 20 is continued by the process of step S24, and the SOC reaches the target SOC. In response to the absence of the power generation request, charging is stopped by the process of step S23. Further, during the execution of any of steps S23 and S24, when the rotational speed Ng of the motor generator 11 falls below the lower limit rotational speed Ng0, the induced voltage charging control is temporarily stopped, and then the rotational speed Ng is again reduced to the lower limit rotational speed. When the speed becomes Ng0 or higher, the induced voltage charging control is resumed, and the processes of steps S23 and S24 are selectively executed according to the power generation request.

As a result, the traveling battery 20 can be charged while maintaining the normal traveling performance during the parallel traveling, and the normal traveling performance can be maintained even after switching to the series traveling or the EV traveling.
This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the first and second embodiments, the induced voltage charging control is individually executed. However, the two embodiments are combined to execute the induced voltage charging control of the first embodiment in the series traveling, and the second embodiment in the parallel traveling. The induced voltage charging control may be executed.

  Further, the hybrid vehicle 1 of the present embodiment does not include so-called engine travel that travels by driving only the engine 3 as a travel mode. However, the engine 1 can also drive the motor generator 11 with the engine 3. If so, instead of the parallel travel of the second embodiment, the induced voltage charging control of FIG. 7 may be executed during engine travel (engine travel).

1 Hybrid vehicle 2 Front motor (travel motor)
3 Engine 5 Rear motor (travel motor)
11 Motor generator (generator)
17 Inverter (power generation control means)
18 Boost converter (Boosting means)
20 Traveling battery 24 Front motor ECU (power generation control means, failure determination means)
27 vehicle ECU (induced voltage charge control means, first charge control prohibition means, second charge control prohibition means)

Claims (6)

In a hybrid vehicle in which a permanent magnet generator driven by an engine is controlled by a power generation control means, and the driving motor is driven and the driving battery is charged by the electric power generated by the generator,
Failure determination means for determining failure of the power generation control means;
When the failure determination means determines that the power generation control means has failed, the generator is driven by the engine without control by the power generation control means, thereby generating an induced voltage in the generator. And an induced voltage charge control means for charging the traveling battery. The induced voltage charging control means is configured to cause the generator to generate a rotation by rotating the generator together with the engine when it is determined that the power generation control means has failed and there is a power generation request to the generator. The traveling battery is charged by controlling the voltage to exceed the voltage of the traveling battery.
The charge control apparatus for a hybrid vehicle according to claim 1. Boosting means for arbitrarily boosting the voltage of the traveling battery and supplying the traveling motor to the traveling motor;
The induced voltage charge control means rotates the generator together with the engine and causes the induced voltage generated by the generator to exceed the voltage of the traveling battery when it is determined that the power generation control means has failed. In addition, when there is no power generation request to the generator, charging of the traveling battery is stopped by controlling the boosted voltage of the boosting unit to be equal to or higher than the induced voltage, and when the power generation request is present, The charging control apparatus for a hybrid vehicle according to claim 1, wherein the traveling battery is charged by controlling the boosted voltage so as to be lower than an induced voltage. Further comprising boosting means for boosting the discharge power of the traveling battery and supplying the boosted electric power to the traveling motor;
The induced voltage charge control means switches the vehicle travel mode to at least engine use travel using the engine when it is determined that a failure has occurred in the power generation control means, and the engine rotation increases according to the vehicle speed. In the operation region where the induced voltage generated by the generator exceeds the voltage of the traveling battery, when there is no power generation request to the generator, the boosted voltage of the boosting means is controlled to be equal to or higher than the induced voltage. 2. The hybrid vehicle according to claim 1, wherein charging of the traveling battery is stopped, and when the power generation request is made, the traveling battery is charged by controlling the boosted voltage to be lower than the induced voltage. Charge control device. First, when the induced voltage of the generator driven by the engine is outside a preset normal range, the generator itself is regarded as a failure, and charging of the traveling battery by the induced voltage charging control means is prohibited. The charge control device for a hybrid vehicle according to any one of claims 1 to 4, further comprising charging control prohibiting means. The battery pack further comprises second charge control prohibiting means for prohibiting charging of the travel battery by the induced voltage charge control means when the charge rate of the travel battery is greater than or equal to a preset charge prohibition determination value. The charge control device for a hybrid vehicle according to any one of claims 1 to 4.

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