JP2006280161A - Regenerative controller for hybrid electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regenerative controller for a hybrid electric vehicle, which can continue regenerative braking even in case that all regenerative power can not be charged into a battery by consuming only surplus regenerative power with accuracy in simple constitution. <P>SOLUTION: This regenerative controller is equipped with a motor generator 102 which is driven by an engine 101 mounted on a vehicle, a battery 103 which is charged with power generated by the motor generator 102, a drive motor 105 which is so constituted as to generate driving force, receiving the power supply from the battery 103 or the motor generator 102, and to be able to regeneratively brake the vehicle, and an engine reversing means (inverter controller )120 which supplies the motor generator with a part of the regenerative power outputted from the drive motor 105 thereby driving the engine 101 when the terminal voltage of the battery 103 gets over a first specified value at regenerative braking. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a regenerative control device that is used in a hybrid electric vehicle and controls regenerative braking.

  In recent years, a hybrid electric vehicle (HEV) including a generator driven by an engine (generally an internal combustion engine), a relatively high voltage battery, a driving motor, and the like has been put into practical use. A parallel hybrid electric vehicle that travels by driving and rotating the drive wheels using both the driving force and the driving force of the driving motor, and a series that travels by driving the driving motor with the power generated by the generator driven by the engine There is a hybrid electric vehicle that combines these features.

In such a hybrid electric vehicle, at the time of braking of the vehicle, the driving motor is operated by the power from the driving wheels to generate electric power to generate the braking force of the vehicle, and the regenerative electric power generated by the driving motor is used as a battery. So-called regenerative braking (regenerative braking) is widely performed.
When performing such regenerative braking, when the battery is charged (close to full charge) or at extremely low temperatures, the amount of power that can be charged to the battery is small, and all the power generated by the drive motor Regenerative power cannot be charged to the battery.

  When excessive regenerative power exceeding the chargeable amount of the battery is supplied to the battery, the battery cannot charge the regenerative power and only the voltage rises. For this reason, in such a case, the regenerative brake is cut to prevent the battery from being damaged due to the battery voltage rising beyond the limit, and the braking force obtained by generating regenerative power is reduced. Instead, a friction brake is used to obtain the braking force of the vehicle by the friction force.

  Cooperative control is used to use both the regenerative brake and the friction brake at the time of braking of the vehicle. However, if the regenerative power cannot be charged to the battery for the reason described above and the regenerative brake is suddenly cut, The braking force borne by the brake must be covered by the friction brake, and the response delay of the friction brake may affect the driver's brake feeling.

In addition, since the battery capacity decreases as the battery deteriorates, the regenerative power cannot often be charged into the battery, and the frequency of use of the friction brake increases. If the vehicle is frequently braked by the friction brake in this way, it is conceivable that wear of the friction material of the friction brake is promoted and the life of the friction brake is shortened.
Therefore, for the purpose of reducing the friction brake load and improving the brake feeling, the power that can be charged to the battery during regenerative braking and the regenerative power are calculated. In this technology, the regenerative power is supplied to a generator and the motor is operated to rotate the engine so that surplus regenerative power is consumed by the rotational load of the engine (Patent Document 1). reference).

According to this technology, at the time of regenerative braking, for example, even when the battery is almost fully charged and there is little electric power that can be charged to the battery, excessive regenerative power is consumed by the rotational load of the engine, and the battery voltage rises due to overcharging. Since it is suppressed and damage is prevented, the regenerative braking can be continued without cutting the regenerative brake, so that the use of the friction brake can be reduced.
JP 2001-238303 A

By the way, in the technique of patent document 1, the charge level of a battery is detected at the time of regenerative braking, and the electric power which can be charged to a battery is set according to the detected charge level of the battery.
However, since the rechargeable power of the battery varies depending on the deterioration state and temperature condition of the battery, it is difficult to accurately grasp this, and if it is attempted to accurately grasp this, the deterioration state and temperature in addition to the battery charge amount It is necessary to consider the conditions, and the apparatus becomes complicated.

  In addition, when the apparatus becomes complicated, the possibility of erroneous detection of the chargeable power of the battery increases. If the battery chargeable power is set lower than the actual chargeable power due to such a false detection or malfunction of the device, the detection error power is not charged to the battery and the engine rotation load. This power is wasted. Alternatively, when the rechargeable power of the battery is set larger than the power that can be actually charged, the regenerative power is excessively supplied to the battery, and the battery may be damaged.

  The present invention has been devised in view of such problems, so that only excessive regenerative power can be consumed accurately with a simple configuration, and regenerative braking can be continued even when the regenerative power cannot be fully charged to the battery. An object of the present invention is to provide a regeneration control device for a hybrid electric vehicle.

  To achieve the above object, a regenerative control device according to a first aspect of the present invention includes a motor generator driven by an engine mounted on a vehicle, and a battery charged by electric power generated by the motor generator. A driving motor configured to receive power supply from the battery or the motor generator to generate a driving force and to regeneratively brake the vehicle, and a terminal voltage of the battery at the time of the regenerative braking is first. Engine reverse drive means for supplying a part of the regenerative power output from the drive motor to the motor generator to drive the engine when the predetermined value is exceeded.

A regenerative control device according to a second aspect of the present invention is the regenerative control device according to the first aspect, wherein the terminal voltage of the battery exceeds a second predetermined value higher than the first predetermined value during the regenerative braking. A regenerative auxiliary brake control means for operating an auxiliary brake of the engine is provided.
According to a third aspect of the present invention, there is provided the regenerative control device according to the second aspect, wherein when the terminal voltage of the battery exceeds the second predetermined value during the regenerative braking, the rotational speed of the engine is gradually increased. And a regenerative engine control means for maintaining the engine speed when a third predetermined value higher than the second predetermined value is exceeded.

  According to a fourth aspect of the present invention, there is provided the regenerative control device according to the third aspect, wherein the regenerative engine control means is configured such that when the battery terminal voltage reaches the third predetermined value, The engine speed is increased in accordance with an increase in the terminal voltage of the battery due to the characteristic that the rotational speed becomes the limit rotational speed, and the drive motor has the battery terminal voltage set to the third predetermined value. When the power reaches, the power generation amount of the regenerative power is controlled to a regenerative power amount equal to the power amount supplied to the motor generator.

Therefore, according to the regenerative control device of the first aspect of the present invention, even when regenerative power larger than the power that can be charged to the battery is generated during regenerative braking, the terminal voltage of the battery has the first predetermined value. When it exceeds, a part of the regenerative power is supplied to the motor generator by the engine reverse drive means so that the engine is driven. Therefore, the surplus regenerative power is consumed by the rotational load of the engine with a simple configuration with high accuracy. And an increase in battery voltage can be suppressed.
As a result, even when the regenerative power cannot be fully charged to the battery, regenerative braking can be continued, reducing the frequency of use of the friction brake to reduce the impact on the brake feeling and the friction brake. It is possible to reduce friction and wear of the friction brake.

  According to the regenerative control device of the second aspect of the present invention, when the battery terminal voltage rises beyond the second predetermined value during regenerative braking, the engine auxiliary brake is activated to increase the engine load. Therefore, consumption of regenerative power can be promoted, and regenerative braking can be continued without being cut even when surplus regenerative power is relatively large.

  According to the regenerative control device of the third aspect of the present invention, during regenerative braking, when the battery terminal voltage rises beyond the second predetermined value, the engine speed is gradually increased, and the engine When the load is increased and the battery terminal voltage exceeds a third predetermined value that is higher than the second predetermined value, the engine speed is maintained, so the engine is allowed to rotate while consuming excess regenerative power. It is possible to prevent the rotation beyond the range.

  According to the regenerative control device of the present invention, the engine speed becomes the limit speed when the battery terminal voltage reaches the third predetermined value during regenerative braking. Excessive regenerative power can be consumed by making maximum use of the engine load, and the battery terminal voltage can be prevented from rising above the third predetermined value to prevent damage to the battery due to voltage rise.

  Embodiments of the present invention will be described below with reference to the drawings. 1-4 is for demonstrating the regeneration control apparatus which concerns on 1st Embodiment of this invention, FIG. 1 is a structure of the principal part of the series type hybrid electric vehicle to which the regeneration control apparatus of this invention is applied. FIG. 2 is a graph showing a state when the braking force Tbrk is requested continuously for a certain time during traveling of the vehicle, and FIG. 2A is a distribution of the braking energy Tbrk corresponding to the elapsed time. FIG. 2B shows the voltage value of the terminal voltage Vb of the battery 103 corresponding to the elapsed time, FIG. 3 is a flowchart showing the control during regenerative braking in this embodiment, and FIG. 4 is the diagram during regenerative braking. It is a graph which shows an engine speed (reverse drive), a battery terminal voltage, and an exhaust valve, (A) shows opening and closing of an exhaust valve, (B) shows the relationship between a battery terminal voltage and an engine speed.

As shown in FIG. 1, the regenerative control device of this embodiment includes an engine 101, a motor generator 102, a battery 103, an inverter 104, a drive motor 105, a drive wheel 106, an engine controller 107, a motor controller 108, and a generator controller 112. It has.
The rotating shaft of the motor generator 102 is connected to the output shaft of the engine 101, and the motor generator 102 rotates by driving the engine 101 to generate power. Further, the motor generator 102 operates by being supplied with electric power. When the motor generator 102 operates, the engine 101 is supplied with fuel by driving the motor generator 102 and rotates without burning. It is supposed to be. In this case, the engine 101 becomes an operating load of the motor generator 102.

A generator controller 112 is connected to the motor generator 102, and the generator controller 112 controls the power generation and driving of the motor generator 102.
A motor controller 108 is connected to the drive motor 105, and the motor controller 108 controls electric power supplied to the drive motor 105 in accordance with an acceleration request at the time of traveling, and a field current supplied to the drive motor 105. Is to control.

The drive shaft of the drive motor 105 is connected to the drive wheels 106 of the vehicle so that power can be transmitted. During regenerative braking, the drive motor 105 is rotated by rotating the drive shaft of the drive motor 105 with the power of the drive wheels 106. Regenerative power is generated at
The engine 101 is provided with an engine speed sensor 111. The exhaust passage of the engine 101 is provided with an exhaust valve 110 that generates an engine braking force by restricting the flow of exhaust gas. During regenerative braking, the exhaust valve 110 is closed to increase the rotational load of the engine 101 and to generate motor power. The consumption of regenerative power by the machine 102 is promoted. That is, here, the exhaust valve 110 functions as an auxiliary brake.

The battery 103 includes a voltage sensor 109 that detects a terminal voltage Vb of the battery 103, and a detection value of the voltage sensor 109 is input to the inverter 104.
The motor generator 102, the battery 103, and the drive motor 105 are electrically connected to each other via the inverter 104, and the generated power of the motor generator 102 is supplied to the battery 103 and the drive motor 105. ing. Further, at the time of regenerative braking, regenerative power generated by the drive motor 105 is supplied to the battery 103 and the motor generator 102. Further, the inverter 104 is electrically connected to the engine controller 107, the motor controller 108, and the generator controller 112 so as to be communicable.

  The inverter 104 adjusts the voltage and current of the power supplied from the motor generator 102 or the battery 103 and converts DC power into AC power to supply stable power to the drive motor 105, or will be described later. In this way, the voltage and current of the regenerative power generated by the driving motor 105 during regenerative braking are adjusted to supply the battery 103 with stable power.

Further, the inverter controller 120, which is a functional means of the inverter 104, stores first to third predetermined values V1 to V3 relating to the voltage of the battery 103 in advance, and stores the limit rotational speed Nemax of the engine 101. ing.
At the time of regenerative braking, when the value of the terminal voltage Vb of the battery 103 input from the voltage sensor 109 is equal to or lower than the first predetermined value, the regenerative power input to the inverter 104 by the control of the inverter controller 120 is All are supplied to the battery 103.

  In addition, when the value of the terminal voltage Vb of the battery 103 is higher than the first predetermined value, the inverter controller 120 supplies a part of the regenerative power input to the inverter 104 to the motor generator 102 and generates the motor power. The generator controller 112 is instructed to operate the machine 102 with a motor. Therefore, a part of the regenerative power input to the inverter 104 is consumed by the rotational load of the engine 101, and the remaining part is supplied to the battery 103. That is, here, the inverter controller 120 functions as engine reverse drive means.

  Further, at the time of regenerative braking, when the terminal voltage Vb of the battery 103 is higher than the second predetermined value, the regenerative power supplied to the motor generator 102 is gradually increased under the control of the inverter controller 120 to Increase the number of revolutions. At this time, the inverter controller 120 determines the terminal voltage Vb of the battery 103 based on the engine speed Ne and the limit speed Nemax input from the engine speed sensor 111 via the engine controller 107 and the terminal voltage Vb of the battery 103. A correlation is set in advance so that the engine speed Ne becomes the limit speed Nemax when the third predetermined value V3 is reached, and the battery is mapped based on a map in which this correlation is mapped [see FIG. 4 (B)]. Control is performed to increase the rotational speed of the engine 101 in accordance with the increase in the terminal voltage Vb of 103.

  When the terminal voltage Vb of the battery 103 reaches the third predetermined value V3, the amount of power supplied to the motor generator 102 is controlled by the inverter controller 120 so that the engine speed Ne is kept at the limit speed Nemax. It has become. At the same time, the inverter controller 120 instructs the motor controller 108 about the amount of power supplied to the motor generator 102, and supplies the regenerative power generated by the motor controller 108 from the inverter 104 to the motor generator 102. Instruct the power to be equal.

That is, here, the inverter controller 120 functions as an engine reverse drive means and a regeneration engine control means.
When the braking force generated by regenerative braking is less than the required braking force, a friction brake (not shown) is activated to complement the braking force of the vehicle.
Therefore, in this regenerative control device, when a braking request is made during traveling of the vehicle, the required braking force (braking torque) is generated by the generation of regenerative power by the driving motor 105 and the frictional force of the friction brake. The regenerative power is absorbed by the power consumed by the engine 101 in addition to the power stored in the battery 103. That is, the braking torque required when the vehicle is braked is distributed to the battery 103, the engine 101, and the friction brake.

For example, when a constant braking torque Tbrk is requested continuously for a certain period of time, the braking torque is distributed according to the elapsed time and the terminal voltage Vb of the battery 103 as shown in FIGS. Is done. Note that FIG. 2 omits the power generation efficiency of regenerative power without considering it for the sake of simplicity.
As shown in FIG. 2A, when a braking torque of Tbrk is requested at time T0, the driving motor 105 generates regenerative power in an amount that generates the braking torque of Tbrk.

In addition, as shown in FIG. 2B, since the terminal voltage Vb of the battery 103 is equal to or lower than the first predetermined value V1 during the period from T0 to T1, all the regenerative power is supplied to the battery 103. That is, the braking force Tbrk is all distributed to the battery 103 during the period from T0 to T1.
Further, as shown at T0 to T1 in FIG. 2B, when the battery 103 becomes nearly unchargeable due to full charge or the like, the terminal voltage Vb of the battery 103 rapidly increases in accordance with power supply.

  During the period from T1 to T2, since the terminal voltage Vb of the battery 103 exceeds the first predetermined value V1, a part of the regenerative power is supplied to the motor generator 102 by the control of the inverter controller 120, and the engine 101 is Reverse driven. The engine speed Ne is controlled so as to be the engine speed Nei at the time of idling. For this reason, a part of the regenerative power is consumed by the rotational load of the engine 101, and the regenerative power supplied to the battery 103 is reduced. That is, in the period from T1 to T2, the braking force Tbrk is distributed to the engine 101 and the battery 103 at a constant rate. In addition, the voltage increase of the terminal voltage Vb of the battery 103 becomes moderate at T1.

  When the terminal voltage Vb of the battery 103 exceeds the second predetermined value V2 at time T2, the exhaust valve 110 in the exhaust passage of the engine 101 is closed, and the rotational load of the engine 101 increases. At this time, the engine speed Ne temporarily decreases, but since the inverter controller 120 rapidly increases the regenerative power supplied to the motor generator 102, the decrease in the engine speed Ne is suppressed. As a result, the amount of regenerative power consumed by the engine 101 at the time point T2 increases rapidly, and the regenerative power supplied to the battery 103 decreases, so that the voltage increase of the terminal voltage Vb of the battery 103 is further moderate at T2. become.

  Further, during the period from T2 to T3, the inverter controller 120 sets the battery 103 so that the rotational speed Ne of the engine 101 becomes the limit rotational speed Nemax when the terminal voltage Vb of the battery 103 reaches the third predetermined value V3. Since the rotation speed Ne of the engine 101 is increased in accordance with the increase in the terminal voltage Vb, the rotation speed Ne of the engine 101 also increases in accordance with the increase in the terminal voltage Vb of the battery 103, and the absorption torque of the engine 101 increases. Therefore, during the period from T2 to T3, as the terminal voltage Vb of the battery 103 increases, the regenerative power supplied to the motor generator 102 increases and the absorption torque of the engine 101 increases. Further, since the regenerative power supplied to the battery 103 decreases as the terminal voltage Vb of the battery 103 increases, the voltage increase of the battery 103 gradually becomes gentle.

  When the terminal voltage Vb of the battery 103 reaches the third predetermined value V3 at time T3, the power generation amount of the regenerative power is reduced to be equal to the power amount supplied to the motor generator 102, and the friction brake Operates. Therefore, the braking torque that is insufficient due to the reduction of the regenerative power after time T3 is supplemented by the frictional force of the friction brake, and all the reduced regenerative power is supplied to the motor generator 102 and not supplied to the battery 103. The terminal voltage Vb does not rise from V3.

Since the regeneration control apparatus according to an embodiment of the present invention is configured as described above, the power generated by the motor generator 102 and the power of the battery 103 are supplied to the drive motor 105 via the inverter 104 when the vehicle is traveling. Then, the driving motor 105 is driven. The vehicle then travels by driving the driving wheels 106 connected to the driving motor 105 so as to be able to transmit power.
Then, when the driver makes a brake request for the vehicle by turning off the accelerator pedal, turning on the brake pedal, or turning on the retarder lever, the regenerative braking starts.

During regenerative braking, the drive shaft of the drive motor 105 is rotated by the power of the drive wheels 106. At this time, a field current for forming a dielectric magnetic field is supplied to the drive motor 105, and regenerative power is generated by the rotation of the drive shaft. The supply amount of the field current is controlled by the motor controller 108 according to an instruction from an ECU (not shown).
Simultaneously with the generation of the regenerative power, a braking torque corresponding to the generated regenerative power is generated on the drive shaft of the drive motor 105, and the generated braking torque is transmitted to the drive wheels 106 to brake the vehicle.

The control during regenerative braking will be further described. For example, the control shown in the flowchart of FIG. 3 is performed. The control shown in FIG. 3 is performed at predetermined intervals.
As shown in FIG. 3, when regenerative braking starts, first, in step S <b> 10, the terminal voltage Vb of the battery 103 detected by the voltage sensor 109 is input to the inverter controller 120.

In step S20, the inverter controller 120 compares the magnitude relationship between the terminal voltage Vb of the battery 103 input to the inverter 104 and the first predetermined value V1 set in advance.
If the terminal voltage Vb of the battery 103 is equal to or lower than the first predetermined value V1, the process proceeds to step S30. In step S30, the regenerative power whose current and voltage are adjusted by the inverter 104 is controlled by the inverter controller 120. Supplied to. At this time, the inverter controller 120 performs control so that regenerative power is not supplied to the motor generator 102. After that, the process returns to the start and the terminal voltage Vb of the battery 103 is detected. At this time, if the braking force due to regenerative braking is insufficient, the braking force is supplemented by a friction brake (not shown) in step S120.

In step S20, when the terminal voltage Vb of the battery 103 is larger than the first predetermined value V1, the process proceeds to step S40, and the inverter 104 supplies the motor generator 102 with regenerative power adjusted in current and voltage. The motor generator 102 is operated to drive the engine 101 in reverse.
In step S50, the terminal voltage Vb of the battery 103 detected in step S10 is compared with the second predetermined value V2. The second predetermined value V2 is a preset value and is a value larger than the first predetermined value V1.

  In step S50, when the terminal voltage Vb of the battery 103 is equal to or lower than the second predetermined value V2, the process proceeds to step S60, and the inverter controller 120 controls the supply amount of regenerative power supplied from the inverter 104 to the motor generator 102. Based on the detected value of the engine speed sensor 111 input from the engine controller 107, feedback control is performed so that the engine speed of the reversely driven engine 101 becomes the engine speed Nei during idling. After that, the process returns to the start and the terminal voltage Vb of the battery 103 is detected. At that time, if the braking force due to regenerative braking is insufficient, it is supplemented by a friction brake.

  If the terminal voltage Vb of the battery 103 is greater than the second predetermined value V2 in step S50, the process proceeds to step S70. In step S70, the inverter controller 120 sends an exhaust valve closing instruction to the engine controller 107, and the engine controller 107 controls the engine 101 to close the exhaust valve. In step S80, based on the engine speed Ne, the limit speed Nemax stored in advance, and the terminal voltage Vb of the battery 103, the inverter controller 120 determines that the engine speed Ne when the terminal voltage Vb of the battery 103 is V2. When the terminal voltage Vb of the battery 103 is V3, the inverter 104 supplies the motor generator 102 with the increase in the terminal voltage Vb of the battery 103 so that the engine speed Ne becomes Nemax. The amount of regenerative power to be supplied is controlled to gradually increase the engine speed.

Next, in step S90, the terminal voltage Vb of the battery 103 detected in step S10 is compared with the third predetermined value V3 again. The third predetermined value V3 is a preset value and is larger than the second predetermined value V2.
In step S90, when the terminal voltage Vb of the battery 103 is equal to or lower than the third predetermined value V3, the process returns to the start and the terminal voltage Vb of the battery 103 is detected. At this time, if the braking force due to regenerative braking is insufficient, it is supplemented by a friction brake in step S120.

  In step S90, when the terminal voltage Vb of the battery 103 is larger than the third predetermined value V3, the process proceeds to step S100. In step S100, based on the control of the inverter controller 120, the inverter 104 increases or decreases the amount of regenerative power supplied to the motor generator 102, and based on the detection value Ne of the engine speed sensor input to the inverter 104 as needed. Feedback control is performed so that the engine speed Ne becomes the limit speed Nemax.

  Along with the processing of step S100, in step S110, the inverter controller 120 inputs the power value supplied to the motor generator 102 to the motor controller 108. The motor controller 108 uses the input power value and the drive motor 105 to The field current supplied to the drive motor 105 is controlled so that the power generation amount of the regenerative power to be generated is equal.

In step S110, when the field current of drive motor 105 is controlled, the amount of power generated by regenerative power decreases, and the braking force due to regenerative braking also decreases (that is, the regenerative braking force is cut). The shortage of braking torque generated by the drive motor 105 when the friction brake is activated is compensated.
Therefore, the terminal voltage of the battery 103 or the rotational speed of the engine 101 during regenerative braking is as shown in FIG.

As shown in FIG. 4, the reverse drive of the engine is not performed in the region where the terminal voltage Vb of the battery 103 detected by the voltage sensor 109 is smaller than the first predetermined value V1 and Vb <V1, and all the regenerative power is supplied to the battery 103. To be supplied.
When the terminal voltage Vb of the battery 103 exceeds the first predetermined value and is in the region of V1 ≦ Vb <V2, the engine 101 is reversely driven, and the engine speed is controlled to be the idling speed Nei. Is done.

When the terminal voltage Vb of the battery 103 exceeds the second predetermined value and reaches the region of V2 ≦ Vb <V3, the amount of power supplied to the motor generator 102 is gradually increased to gradually increase the engine speed. . At the same time, the exhaust valve 110 is closed, and the rotational load of the engine increases.
When the terminal voltage Vb of the battery 103 reaches the third predetermined value, the engine speed Nemax at that time is stored and held, and the engine speed is maintained in a state of Nemax in the region of V3 ≦ Vb. In this region, it is determined that the terminal voltage of the battery 103 has risen to the limit, so that the amount of power generated by the regenerative power generated by the drive motor 105 is approximately equal to the amount of power supplied to the motor generator 102. The field power of the drive motor 105 is controlled. As a result, the amount of power generated by the regenerative power is reduced, and the lack of braking force due to regenerative braking is compensated by the friction brake.

Further, as shown in FIG. 2B, the terminal voltage Vb of the battery 103 in the regenerative control device charges the battery 103 with regenerative power when regenerative braking starts at time T0. And when the battery 103 becomes unchargeable, surplus regenerative electric power is not charged, but the terminal voltage Vb of the battery 103 rises rapidly.
At time T1, when the engine 101 is driven in reverse, the regenerative power for the engine driving load is consumed by the engine 101. Therefore, an increase in the terminal voltage Vb of the battery 103 is suppressed, and the terminal voltage of the battery 103 is suppressed. The voltage increase rate of Vb becomes moderate at T1.

At time T2, the terminal voltage Vb of the battery 103 reaches the second predetermined value V2, the exhaust valve 110 is closed, and the load applied to the rotation of the engine increases. Therefore, the regeneration consumed for reverse driving of the engine 101 is performed. The power increases, and the voltage rise of the terminal voltage Vb of the battery 103 is further moderated.
Further, during the period from T2 to T3, the engine speed Ne increases as the terminal voltage Vb of the battery 103 increases, so that the regenerative power consumed for reverse driving of the engine 101 gradually increases in accordance with the increase in the engine speed Ne. And the rate of increase of the terminal voltage Vb of the battery 103 also gradually decreases.

After T3, the regenerative power larger than the power required for reverse driving of the engine 101 is not generated, so that the terminal voltage Vb of the battery 103 is constant in a state substantially equal to the third predetermined value V3 and beyond. It will not rise.
The graphs of FIGS. 2 and 4 are examples when regenerative power greater than the absorption torque in the engine 101 at time T3 is generated. For example, the surplus regenerative power is not so large and the rotation speed of the engine 101 is If the engine 101 rotates at the idling rotational speed Nei, the terminal voltage Vb of the battery 103 does not increase at the time when surplus regenerative power is consumed, and the subsequent control is performed. Not done.

Therefore, when the terminal voltage Vb of the battery 103 is equal to or lower than the first predetermined value V1 in step S20, there is still a sufficient margin until the allowable voltage of the battery 103, so that the regenerative power is not performed without reverse driving of the engine. Is supplied to the battery 103, and regenerative power is not wasted by reverse driving of the engine.
Further, when the terminal voltage Vb of the battery 103 is higher than the first predetermined value V1 in step S20, it is preferable from the viewpoint of maintenance and management of the battery 103 that the battery 103 collects (recharges) all regenerative power. In this state, the engine 101 is driven in reverse so that excessive regenerative power is consumed by the engine 101, thereby suppressing an increase in the terminal voltage Vb of the battery 103.

When the terminal voltage Vb of the battery 103 is equal to or lower than the second predetermined value V2 in step S50, the terminal voltage Vb of the battery 103 is not so high, so the engine 101 is at the engine speed at idling. It is driven gently by a certain Nei.
Further, if the terminal voltage Vb of the battery 103 is higher than the second predetermined value V2 in step S50, it is considered that the terminal voltage Vb of the battery 103 is high and excessive regenerative power is large, so the exhaust valve 110 is closed. Thus, the load applied to the rotation of the engine 101 is increased, and the regenerative power supplied to the motor generator 102 is increased. Therefore, the amount of regenerative power supplied to the battery 103 is reduced, and the increase in the terminal voltage Vb of the battery 103 is suppressed. Can do.

In step S80, when the terminal voltage Vb of the battery 103 is V3, the rotational speed Ne of the engine 101 is increased according to the increase of the terminal voltage Vb of the battery 103 so as to become the limit rotational speed Nemax. It is possible to suppress the increase in the terminal voltage Vb of the battery 103 by consuming the maximum possible regenerative power.
When the terminal voltage Vb of the battery 103 reaches V3 in step S90, the regenerative power that can be consumed by the engine 101 is the limit, and the terminal voltage Vb of the battery 103 is also increased to the limit. Therefore, only the amount of regenerative power equal to the amount of power that can be consumed by the engine 101 is generated, so that all the regenerative power is consumed by the engine 101 and is not supplied to the battery 103. The voltage rise of the terminal voltage Vb is completely suppressed, and damage to the battery 103 due to the voltage rise can be reliably prevented.

  In addition, since the amount of surplus regenerative electric power that is not charged in the battery 103 is determined based on the terminal voltage Vb of the battery 103, even when the chargeable electric energy of the battery 103 such as the charging state or temperature state of the battery 103 is different, The battery 103 can be charged with regenerative power that can be recharged without waste, can suppress a rise in the voltage of the battery 103 due to excess regenerative power, and continue regenerative braking even when the battery 103 is in an unchargeable state. Thus, the frequency of use of the friction brake can be reduced.

[Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
In the above-described embodiment, the first predetermined value V1 is a value set in advance to detect that the battery 103 cannot be charged with regenerative power, but the value of V1 can be changed as appropriate. . For example, the terminal voltage Vb ₀ of the battery 103 before the start of regenerative braking may be stored, and a value higher than the Vb ₀ by a predetermined value may be set as V1.

  In this way, when the battery 103 becomes unable to charge regenerative power, the terminal voltage Vb of the battery 103 rapidly increases, so that the same effect as the above-described embodiment can be obtained even if V1 is set in this way. In addition, since a different value is set as the first predetermined value V1 according to the charging state, deterioration state, temperature condition, etc. of the battery 103, the engine 101 is reversely driven with a simple configuration and more accurately. As a result, surplus regenerative power can be consumed by the engine 101.

  As for the second and third predetermined values, the second predetermined value V2 is higher than the first predetermined value V1, and the third predetermined value V3 is higher than the second predetermined value V2. Although it can be set as appropriate, the third predetermined value V3 needs to be set to a value lower than the limit voltage of the battery 103. In this way, the voltage increase of the battery 103 in the present invention does not become higher than the value in the vicinity of the third predetermined value V3, so that the damage of the battery 103 due to the voltage increase can be reliably prevented.

  The present invention is not limited to a series hybrid electric vehicle, and can be widely applied as long as it includes an engine, a motor generator, and a drive motor and performs regenerative braking.

It is a schematic diagram which shows the principal part of the regeneration control apparatus which concerns on one Embodiment of this invention. It is an example of the time chart which shows the engine speed and battery voltage in the regeneration control apparatus which concerns on one Embodiment of this invention, Comprising: (A) shows the relationship between a battery voltage and engine speed, (B) shows elapsed time. It shows an increase in the battery voltage accordingly. It is a flowchart which shows the control at the time of regenerative braking in the regenerative control apparatus which concerns on one Embodiment of this invention. It is a graph which shows the engine speed (reverse drive) with respect to the battery terminal voltage at the time of the regenerative braking of the regenerative control apparatus which concerns on one Embodiment of this invention, and the state of an exhaust valve, Comprising: (A) shows the open / close state of an exhaust valve. (B) shows the state of the engine speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Engine 102 Motor controller 103 Battery 104 Inverter 105 Driving motor 106 Driving wheel 107 Engine controller 108 Motor controller 109 Voltage sensor 110 Exhaust valve 111 Engine speed sensor 112 Generator controller 120 Inverter controller (engine reverse drive means)

Claims (4)

A motor generator driven by an engine mounted on the vehicle;
A battery to be charged by the electric power generated by the motor generator;
A driving motor configured to receive power supply from the battery or the motor generator to generate a driving force and regeneratively brake the vehicle;
When the battery terminal voltage exceeds a first predetermined value during the regenerative braking, engine reverse drive is performed to drive the engine by supplying a part of the regenerative power output from the drive motor to the motor generator. Means,
A regenerative control device for a hybrid electric vehicle, comprising: Regenerative auxiliary brake control means for operating an auxiliary brake of the engine when a terminal voltage of the battery exceeds a second predetermined value higher than the first predetermined value during the regenerative braking is provided. The regenerative control device for a hybrid electric vehicle according to claim 1. When the terminal voltage of the battery exceeds the second predetermined value during the regenerative braking, when the engine speed is gradually increased and reaches a third predetermined value higher than the second predetermined value The regenerative control device for a hybrid electric vehicle according to claim 2, further comprising regenerative engine control means for maintaining the engine speed. The regenerative engine control means responds to an increase in the terminal voltage of the battery due to the characteristic that the engine speed becomes the limit speed when the terminal voltage of the battery reaches the third predetermined value. Increase the engine speed,
When the terminal voltage of the battery reaches the third predetermined value, the drive motor controls the amount of power generated by the regenerative power to be equal to the amount of regenerative power supplied to the motor generator. The regenerative control device for a hybrid electric vehicle according to claim 3, wherein:

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