JP2007210586A - Vehicle drive system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle drive system for appropriately controlling a vehicular yaw moment and for improving vehicular response. <P>SOLUTION: The system includes two AC motors 6a, 6b individually driving a right and a left rear wheels of a vehicle, and two inverters 8a, 8b driving the two motors 6a, 6b, respectively. Motor controllers 14a, 14b, an HEV controller 32, and a voltage transformation controller 16 controls voltages of the motors 6a, 6b, the inverters 8a, 8b, and a voltage control means so as to output optimum torques to each of the rear wheels according to the remaining quantity of a battery and the traveling state of the vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle drive system that drives a hybrid vehicle, and more particularly to a vehicle drive system that is suitable for rear wheel yaw moment control.

  As a vehicle drive system for a hybrid vehicle, for example, as described in JP-A-11-301293, the front wheels are driven by an engine, the rear wheels are driven by two right and left motors, and the two rear wheel motors are independently provided. It is known to control the yaw moment of the vehicle with high accuracy by controlling the speed to the above.

JP-A-11-301293

  However, in Japanese Patent Application Laid-Open No. 11-301293, when the battery is overdischarged or overcharged, the torques of the left and right wheels for controlling the motor are corrected, and the battery is overdischarged or overcharged. Since charging is prevented, the required torque cannot be produced when the battery is overdischarged or overcharged. Therefore, although the target yaw moment can be satisfied, there is a problem that the acceleration performance during acceleration and the responsiveness of deceleration during deceleration are reduced.

  An object of the present invention is to provide a vehicle drive system that can accurately control the yaw moment of the vehicle and improve the response of the vehicle.

(1) In order to achieve the above object, the present invention provides two AC motors that independently drive the left and right rear wheels of a vehicle, two inverters that respectively drive the two AC motors, and the two AC motors. And a motor control unit for controlling the inverter, a battery for storing electrical energy, a voltage control means provided between the battery and the two inverters, and for controlling the input voltage of the two inverters to move up and down, and a vehicle A vehicle drive system for a hybrid vehicle, comprising: a running state detecting means for detecting the running state of the vehicle; and a control means for controlling the inverter, the AC motor, and the generator according to a torque required from the vehicle, According to the remaining amount of the battery and the traveling state of the vehicle detected by the traveling state detecting unit, the rear wheel To issue the optimum torque to the wheels, and the said motor inverter, in which so as to control the voltage of said voltage control means.
With this configuration, the yaw moment of the vehicle can be controlled with high accuracy and the responsiveness of the vehicle can be improved.

  (2) In the above (1), preferably, the control means calculates energy consumed by each motor or energy regenerated from a torque command value to the two motors for obtaining an optimum torque of the rear wheel. A left and right motor calculated by the energy calculating means, comprising: energy calculating means for calculating; and battery state detecting means for calculating the state of charge of the battery when an optimum torque is output to each of the rear wheels. When the battery state detecting means determines that the battery is overcharged, the regenerative energy is increased to reduce the regenerative energy and the battery is charged. Torque distribution means for outputting a required torque without being overcharged is provided.

  (3) In the above (2), preferably, the control means is obtained from one of the left and right AC motors when the energy consumed by the left and right motors calculated by the energy calculating means is positive and negative. The voltage of the voltage control means is controlled so that the other AC motor is driven using regenerative energy.

  (4) In the above (3), preferably, the control means is configured such that the energy consumed by the left and right motors calculated by the energy calculating means is positive and negative, and the drive energy of one of the left and right AC motors is the other When the battery state detection means determines that the battery is over-discharged (when the state of charge of the battery is less than or equal to a predetermined value), the AC motor provided on the front wheels is smaller than the regenerative energy obtained from the AC motor. The rear wheel AC motor is driven by supplementing the electric power that is insufficient to generate electric power and drive the rear wheel.

  (5) In the above (3), preferably, the control means is configured such that the energy consumed by the left and right motors calculated by the energy calculating means is positive and negative, and the drive energy of one of the left and right AC motors is the other When the battery state detection means determines that the battery is overcharged (when the state of charge of the battery is greater than or equal to a predetermined value), the battery is driven by the rear wheels from the battery. Therefore, the rear-wheel AC motor is driven by making up for the insufficient power.

  (6) In the above (1), preferably, an internal combustion engine that supplies driving power to the front wheels, an inverter that converts DC power of the battery into AC power, and AC power of the inverter are used to drive the front wheels. An alternating-current motor that supplies driving force or is driven by the rotational force of the internal combustion engine and that can generate power, and the control means provides torque command values to the two motors for obtaining the optimum torque of the rear wheels. More, an energy calculation means for calculating energy consumed by each motor or energy to be regenerated, and a battery state for calculating the state of charge of the battery when an optimum torque is output to each rear wheel. Detecting means, wherein the energy consumed by the left and right motors calculated by the energy calculating means is negative at the same time, in the battery state detecting means When it is determined that the battery is overcharged, the output of the internal combustion engine is reduced, the AC motor provided on the front wheels is driven, and the battery power is consumed, thereby reducing regenerative energy and charging the battery. Torque distribution means for outputting a required torque without being overcharged is provided.

(7) In order to achieve the above object, the present invention provides an AC motor for driving a rear wheel of a vehicle, an inverter for driving the AC motor, a motor control unit for controlling the AC motor and the inverter, A battery for storing electrical energy; a voltage control means for controlling raising and lowering the input voltage of the inverter; a running state detecting means for detecting the running state of the vehicle; A vehicle drive system for a hybrid vehicle comprising a control means for controlling the inverter, the AC motor and the generator according to a required torque, the vehicle drive system being provided between the rear wheel and the motor, Distributing the driving force to the left and right rear wheels, and distributing means whose variable distribution ratio is variable, the control means comprising: In accordance with the running state of the vehicle detected by the running state detecting means and, to emit the optimum torque to the wheels of the rear wheel, in which so as to control the distribution ratio by the distribution means.
With this configuration, the yaw moment of the vehicle can be controlled with high accuracy and the responsiveness of the vehicle can be improved.

  According to the present invention, it is possible to accurately control the yaw moment of the vehicle and improve the responsiveness of the vehicle.

Hereinafter, the configuration and operation of the vehicle drive system according to the first embodiment of the present invention will be described with reference to FIGS.
First, the overall configuration of the vehicle drive system according to the present embodiment will be described with reference to FIG.
FIG. 1 is a system block diagram showing the overall configuration of the vehicle drive system according to the first embodiment of the present invention.

  Here, the case where the vehicle drive system according to the present embodiment is applied to a hybrid vehicle using an engine and a motor / generator at the front and two AC motors for independently driving the left and right at the rear will be described as an example. .

  The hybrid vehicle 1 includes an engine 3, a motor / generator (M / G) 4, an AC motor 6a for driving the left rear wheel, an AC motor 6b for driving the right rear wheel, a battery 31, and a DC / DC converter. 33. The driving force of the engine 3 and the M / G 4 is transmitted to the front wheel 2 via the transmission 30 and the axle 13A to drive the front wheel 2. The output of the engine 3 is controlled by an electronic control throttle 11 that is driven by a command from an engine control unit (ECU) 15. The electronic control throttle 11 is provided with an accelerator opening sensor 12, which detects the accelerator opening. Further, the ECU 15 controls the transmission 30. The output of the engine 3 may drive not only the front wheels 2 but also the M / G 4. M / G 4 is driven by a motor using electric power stored in battery 31 when driving front wheel 2. When regenerative braking is performed by the front wheels 2, regenerative power obtained by the M / G 4 is supplied to the battery 31. When generating power, the M / G 4 uses the power of the engine 3 to output AC power as a generator.

  The inverter 10 is provided for arbitrarily controlling required power in the M / G 4, converts the DC power stored in the battery 31 into AC power, and supplies the AC power to the M / G 4. During regenerative braking or power generation, AC power is converted to DC power by the inverter 10 and supplied to the battery 31.

  The AC motor 6a and the AC motor 6b can drive and regenerate. The driving forces of the AC motors 6a and 6b are transmitted to the rear wheels 5a and 5b via the clutches 9a and 9b, the gears 7a and 7b, and the axles 13Ra and 13Rb, respectively. 5b is driven. When the gear 7a and the clutch 9a or the gear 7b and the clutch 7b are connected, the rotational force of the AC motor 6a or the AC motor 6b is transmitted to the axle 13Ra or the axle Rb to drive the rear wheel 5a or the rear wheel 5b. When the clutch 9a or the clutch 9b is disengaged, the AC motor 6a or the AC motor 6b is mechanically disconnected from the rear wheel 5a or the rear wheel 5b, and the rear wheel 5a or the rear wheel 5b does not transmit the driving force to the road surface.

  1 illustrates a configuration in which the AC motor 6a and the AC motor 6b are connected via an opening / closing mechanism such as the clutch 9a and the clutch 9b. However, a configuration in which the AC motor 6a and the AC motor 6b are directly connected may be used. In FIG. 1, the gears 7a and 7b are illustrated as speed reducers, but may be a multi-stage transmission. At the time of braking, the AC motor 6a or the AC motor 6b is regenerated by connecting the gear 7a and the clutch 9a or the gear 7b and the clutch 9b with regenerative torque from at least one of the rear wheel 5a and the rear wheel 5b. Obtainable.

  An inverter 8a and an inverter 8b are provided so that required power can be controlled arbitrarily in the AC motor 6a and the AC motor 6b, and the DC power stored in the battery 31 is converted into AC power. It supplies to AC motor 6b.

  The HEV controller 32 is connected to the ECU 15, the motor controller 14A, the motor controller 14a, the motor controller 14b, the voltage conversion controller 16 that controls the DC / DC converter 33, and a communication means such as CAN. Based on vehicle information such as acceleration and yaw rate, control of the entire drive system such as calculating command values to the front wheel M / G 4 and the rear wheel AC motor 6a, AC motor 6b, DC / DC converter 33 is performed. It is a controller to perform.

  The motor controller 14 </ b> A controls the M / G 4 and the inverter 10 based on the engine speed and torque command obtained from the HEV controller 32. The motor controller 14a controls the AC motor 6a and the inverter 8a based on the engine speed and torque command obtained from the HEV controller 32. The motor controller 14b controls the AC motor 6b and the inverter 8b based on the engine speed and torque command obtained from the HEV controller 32.

  The DC / DC converter 33 is provided between the left and right inverters 8a and 8b, and the output of the battery 31 becomes a voltage necessary for outputting the torque required for the AC motor 7a and the AC motor 7b. Power conversion. The voltage conversion controller 16 is a controller that controls the voltage of the DC / DC converter 33. Here, in this example, the DC / DC converter 33 is used as the voltage control unit. However, a configuration in which voltage conversion is performed by switching a switch or the like may be used.

Next, the configuration and operation of the HEV controller 32 used in the vehicle drive system according to the first embodiment of the present invention will be described with reference to FIGS.
Initially, the structure of the HEV controller 32 used for the vehicle drive system by this embodiment is demonstrated using FIG.
FIG. 2 is a block diagram showing the configuration of the HEV controller used in the vehicle drive system according to the first embodiment of the present invention.

  The HEV controller 32 determines the torques of the two AC motors 6a and 6b for the rear wheels so as to control the left and right rear wheels independently so as to control the optimum yaw moment according to the state of the battery. . At the same time, the driving force for the front wheels 2 is determined and distributed to the engine 3 and the M / G 4. Therefore, in the HEV controller 32, in addition to the information indicating the battery voltage detected by the battery voltage sensor SE1 and the battery remaining amount detected by the battery remaining amount sensor SE2, the vehicle position information is detected by the accelerator opening sensor SE3. The accelerator opening θ, the brake signal indicating the depression state of the brake detected by the brake switch SE4, the steering angle δ detected by the steering angle sensor SE5, the vehicle speed V detected by the vehicle speed sensor SE6, and the longitudinal acceleration sensor SE7. , The lateral acceleration Gy detected by the lateral acceleration sensor SE8, the yaw rate Yr detected by the yaw rate sensor SE9, the wheel speed Vfl of each wheel detected by the wheel speed sensor SE10 of each wheel (previous Left), Vfr (front ), Vrl (rear left), Vrr (rear right) is input.

  The HEV controller 32 includes a running state calculation unit 32A, a target yaw moment calculation unit 32B, left and right rear wheel target torque calculation unit 32C, a rear wheel motor torque command calculation unit 32D, an energy conversion unit 32E, and a torque distribution calculation unit. 32F.

  The driving state calculation unit 32A estimates the degree of acceleration / deceleration from the accelerator pedal opening θ and the brake signal from the driver's accelerator pedal depression operation and brake operation. Further, the driving power Pall and the driving force Tall required for the front-rear acceleration are calculated from the vehicle information such as the speed and the vehicle weight and the information indicating the road condition such as the road surface friction coefficient μ.

  The target yaw moment calculator 32B estimates the turning radius targeted by the driver from the steering angle δ corresponding to the steering wheel operation amount of the driver. Considering the movement of the load accompanying the turning of the vehicle, the friction coefficient μ of the road surface is estimated using each sensor value such as the turning radius, the vehicle speed V, and the lateral acceleration Gy. Also, the load movement amount in the front-rear and lateral directions is calculated using the front-rear acceleration Gx and the lateral acceleration Gy. Further, the driving force Tall necessary for the acceleration / deceleration before and after calculated by the traveling state calculation unit 32A is distributed back and forth in consideration of the vehicle weight and the center of gravity. The torque allocated to the front wheels is calculated as Tfront, and the torque allocated to the rear wheels is calculated as Trear. Further, the driving force that can be generated in each of the front, rear, left and right wheels is calculated from the load movement amount, and the target yaw moment To is calculated.

  The left and right rear wheel target torque calculation unit 32C distributes the total torque Trear output from the rear wheels to the left and right, and calculates the target torques Trl (rear left) and Trr (rear right) of the left and right rear wheels. The left and right rear wheel target torque here is necessary for the acceleration / deceleration calculated by the traveling state calculation unit 32A in addition to the torque required to generate the target moment To calculated by the target yaw moment calculation unit 32B. Torque (drive power Pall), that is, acceleration is taken into account.

  The rear wheel motor torque command calculation unit 32D calculates torque command values Tmrl for the left and right rear wheel AC motors 6a and 6b from the left and right rear wheel target torques Trl and Trr calculated by the left and right rear wheel target torque calculation unit 32C. * And Tmrr * are calculated. At this time, if the target torques Tmrl * and Tmrr * calculated by the rear wheel motor torque command calculation unit 32D exceed the motor specifications, the process returns to the target yaw moment calculation unit 32B so that the limited target torque is obtained. Review the torque distribution before and after, and calculate again.

  The energy conversion unit 32E calculates the consumed energy or regenerative energy Prl of each wheel from the motor torques Tmrl * and Tmrr * of the left and right wheels calculated by the rear wheel motor torque command calculation unit 32D and the motor rotational speeds ωml and ωmr. .

Here, the processing contents of the energy conversion unit 32E of the HEV controller 32 used in the vehicle drive system according to the present embodiment will be described with reference to FIG. 3 using the left rear wheel AC motor 6a as an example.
FIG. 3 is a flowchart showing the processing contents of the energy conversion unit of the HEV controller used in the vehicle drive system according to the first embodiment of the present invention.

  First, in step S101, the energy conversion unit 32E inputs the motor rotational speed ωmrl of the left rear wheel AC motor 6a.

  Next, in step S101, the energy conversion unit 32E inputs the torque command Tmrl * of the AC motor 6a for the left rear wheel.

  Next, in step S103, the energy conversion unit 32E determines whether the motor rotation speed ωmrl and the torque command Tmrl * have the same sign, thereby determining whether energy is consumed or regenerated. In step S103, when the torque command Tmrl * and the motor rotation speed ωmrl have the same sign, it is determined that the mode consumes energy.

If it is determined that the energy consumption mode is set, in step S104, Prl is calculated as energy consumption by the following equation (1).

Prl = Tmrl * · ωmrl / α (0 <α <1) (1)

Here, α represents the overall efficiency of the AC motor 6a and the inverter 8a for the left rear wheel. The value of the efficiency α holds, for example, the efficiency with respect to the rotation speed and torque of the motor as a map.

In step S103, when the torque command Tmrl * and the motor rotation speed ωmrl have different signs, the energy is determined as the regenerative mode, and in step S105, Prl is calculated as the regenerative energy by the following equation (2).

Prl = Tmrl * · ωmrl · α (0 <α <1) (2)

Although the above is an example of the left rear wheel, the energy conversion unit 32E calculates the consumed energy Prr during driving and the regenerative energy Prr during braking similarly for the right rear wheel.

From the calculated energy consumption or regenerative energy of the left and right rear wheels, the total energy Pr consumed by the motor and the inverter in the rear wheels is calculated by the following equation (3). Since the total energy Pr becomes positive when the motor or the inverter consumes, the energy flowing from the DC / DC converter 33 in the direction of the inverters 8a and 8b is defined as positive.

Pr = Prl + Prr (3)

The torque distribution calculation unit 32F refers to the remaining battery level based on the front wheel torque Tfront calculated by the target yaw moment calculation unit 32B and the consumed energy or regenerative energy Prl of each wheel calculated by the energy conversion unit 32E. Considering the case where it is determined that the battery 31 is overcharged or overdischarged, the torque command to the M / G 4, the torque command to the engine 3, the torque command to the left rear wheel motor 6 a, and the right rear wheel motor 6 b The torque command is calculated.

First, the torque distribution calculation unit 32F estimates the state of the battery 31 when the consumption energy or the regenerative energy as described above occurs, and determines overcharge or overdischarge. The current SOC 31 of the battery 31, the total energy Pr calculated above, and torque commands Tmrl * and Tmrr * to the left and right rear wheels are input to determine whether the state of charge of the battery 31 is overcharged or overdischarged. To do.
Here, the state of charge SOC of the battery will be described with reference to FIG.
FIG. 4 is an explanatory diagram of the storage state of the battery.

  The value SOC indicating the storage state of the battery 31 represents the current storage state of the battery with respect to the entire capacity of the battery 31 by 0% to 100%, and has a characteristic of increasing as the battery voltage Vbatt increases. Yes.

  For example, the torque distribution calculation unit 32F determines a limit value for preventing the battery from failing when the rear wheel is driven or regenerated by the torque command Tmrl * and the torque command Tmrr * with respect to the current battery state SOC. . For example, the energy conversion unit 32E holds the limit values Tmrl_lim and Tmrr_lim of each torque and the limit value Pr_lim of the total energy for the current SOC value as map data based on the actual machine. In this way, the torque command to each component (motor, engine, generator) is calculated in consideration of the state of the battery.

Next, a torque command calculation method in the torque distribution calculation unit 32F of the HEV controller 32 used in the vehicle drive system according to the first embodiment of the present invention will be described with reference to FIGS.
5 and 8 to 11 are flowcharts showing a torque command calculation method in the torque distribution calculation unit of the HEV controller used in the vehicle drive system according to the first embodiment of the present invention.

  In FIG. 5, the torque distribution calculation unit 32 </ b> F performs case classification according to a combination pattern of driving and regeneration of the two AC motors 6 a and 6 b for the left and right rear wheels and the energy sum.

  First, in step S110, the left and right rear wheel motor torque command values Tmrl * and Tmrr * are examined to determine whether they are positive or negative, and are classified into four cases. Here, whether the AC motors 6a and 6b for driving the left and right rear wheels 5a and 5b are powered or regenerated respectively, the combination of them “powering & powering”, “regeneration & regeneration”, “powering & regeneration” ”And“ 0 & 0 ”. In these classifications, yaw moment can be generated by making a difference in the magnitudes of the left and right torques.

If one of the torque command Tmrl * and the torque command Tmrr * is positive and the other is negative among the combinations examined in step S110, the process proceeds to step S111. In step S111, it is checked whether the sum Pr of the energy driven by the two rear-wheel AC motors 6a and 6b calculated by the equation (3) is positive or negative, and is classified into a positive case and a negative case. That is, when the left and right rear wheels are powering and regenerating, the sign of the energy sum Pr differs depending on whether the powering or regenerative torque is greater. Therefore, when these are put together, they are classified into five types as shown in the following (Table 1).

Here, a method of generating the yaw moment will be described with reference to FIG.
FIG. 6 is an explanatory diagram of the principle of generation of the yaw moment.

  Fig. 6 shows the turning of the right curve, and understeer is affected by road surface conditions, etc., and when the vehicle is about to slide outward, an inward moment is generated to avoid understeer can do. This is generally performed by control of VDC (Vehicle Dynamics ConTrol) or the like.

  In the present embodiment, the generation of such a moment is realized by using a difference in driving force between the left and right rear wheels. As a method for generating a difference in driving force, the combinations were classified into five combinations listed in (Table 1). Note that, as in case E, when the left and right driving forces are both 0, the yaw moment is not generated.

  Next, the two AC motors 6a, 6b, M / G4, and the driving method of the engine 3 in consideration of the state of the battery 31 will be described for each case of (Table 1).

  First, in case A, since both the left and right rear wheels are in powering, it is assumed that the driver is stepping on the accelerator while accelerating. When an inward moment is generated to the right as in the example of FIG. 6, the driving force of the left wheel 5a is made larger than the driving force of the right wheel 5b as shown in FIG. 7 (a). Make a difference in the driving force of both wheels.

  Here, the calculation processing contents of the torque distribution calculation unit 32F in case A will be described with reference to FIG.

  First, in step S120, the torque distribution calculation unit 32F inputs the state of charge SOC of the battery, and checks whether the battery state SOC exceeds a certain threshold SOC_High in step S121. SOC_High is a value that means that the battery state SOC is at a high level, for example, 70% to 80%. If it is determined in step S121 that the battery state SOC is at a high level, it is determined that there is no problem even if the left and right wheels are powered because the state of charge of the battery is high, and the process proceeds to step S127.

  When it is determined in step S121 that the battery state SOC is not high to some extent, the process proceeds to step S123, and it is checked whether the battery state SOC is larger than a certain threshold SOC_Low. The threshold value SOC_Low is a value that means that the battery state SOC is at a low level, for example, 30% to 40%.

  If it is determined in step S123 that the battery state SOC is higher than the lower limit value, the process proceeds to step S124. At this time, as the state of the battery 31, the battery state SOC is an intermediate value, for example, within a range of 40% to 60%. Therefore, in step S124, when the left and right rear wheels are driven (powering) with the torque command values Tmrl * and Tmrr *, what happens to the state of the battery 31, the torque limit values Tmrl_lim, Tmrr_lim and the energy total limit. Judgment is made based on the value Pr_lim.

  If it is determined in step S124 that there is no problem in the battery state, it is determined that there is no problem even if both left and right wheels are powered.

  If it is determined in step S123 that the SOC is low, or if it is determined in step S124 that the battery 31 will fail (over discharge) when a predetermined torque is applied, power is supplied from the battery 31. This means that the desired torque required for the rear wheels cannot be produced. In this embodiment, since M / G4 is mounted on the front, it is possible to generate power with M / G4. Therefore, it progresses to step S125 and it produces electric power with M / G4 of a front wheel.

  In step S127, torque command values for the engine 3 and M / G4 at the front are calculated.

  Next, in step S128, a voltage command value to the DC / DC converter 33 is calculated.

  As described above, the torque distribution calculating unit 32F performs the torque command to the M / G 4 in case A, the torque command to the engine 3, the torque command to the left rear wheel motor 6a, and the torque command to the right rear wheel motor 6b. Is calculated.

  Next, the calculation processing contents of the torque distribution calculation unit 32F in case B will be described with reference to FIG.

  In Case B, both the left and right rear wheels are regenerated, so the driver's accelerator and brake pedaling conditions are assumed to be decelerating. In the example of FIG. 6, when both wheels are braked when generating an inward yaw moment to the right, as shown in FIG. 7B, the wheel 5b on the right side of the braking force of the left wheel 5a. By increasing the braking force of, it is possible to make a difference in the braking force of both wheels.

  Therefore, in step S130, the torque distribution calculation unit 32F inputs the charge state SOC of the battery, and in step S131, checks whether the battery state SOC is smaller than a certain threshold SOC_Low. If it is determined that the battery state SOC is at a level lower than the predetermined limit value, there is no possibility that the battery will be fully charged even if regenerative braking is performed on both the left and right wheels, the process proceeds to step S137.

  If it is determined in step S131 that the battery state SOC is higher than the lower limit threshold value, the process proceeds to step S133, and it is checked whether or not the battery state SOC is lower than the upper limit threshold value SOC_High.

  When it is determined in step S133 that the battery state SOC is lower than the upper limit value, the process proceeds to step S134. In step S134, it is determined what happens to the battery state when the left and right rear wheels are regeneratively braked with the torque command values Tmrl * and Tmrr *. If it is determined in step S134 that there is no problem in the battery state, it is determined that there is no possibility that the battery 31 is fully charged even if regeneration is performed on both the left and right wheels, and the process proceeds to step S137.

  If it is determined in step S133 that the battery state SOC is in a high state, or if it is determined in step S134 that the battery state will fail (become fully charged) when a predetermined torque is applied, The battery situation means that you can't charge any more energy. At this time, the process proceeds to step S135, and surplus power is consumed by the motor. In the present embodiment, since the front wheels also have M / G4, it is possible to reduce the engine output and drive the motor of the front wheels M / G4 to consume battery power. In addition, it is possible to increase the loss of at least one of the rear motors and consume excess power. Furthermore, it is possible to use a friction brake together without regenerating.

Next, in step S137, torque command values for the engine 3 and M / G4 at the front are calculated.
In step S138, a voltage command value to the DC / DC converter 33 is calculated.

  As described above, the torque distribution calculating unit 32F performs the torque command to the M / G 4 in case B, the torque command to the engine 3, the torque command to the left rear wheel motor 6a, and the torque command to the right rear wheel motor 6b. Is calculated.

  Next, the calculation processing contents of the torque distribution calculation unit 32F in case C and case D will be described with reference to FIG.

  Case C and Case D are cases where one of the rear wheels is powered and the other is regenerating, so the driver's accelerator or brake can be depressed at any time during deceleration, acceleration, or constant running. It is done. In the example of FIG. 6, in order to generate an inward moment to the right side, as shown in FIG. 7C, the regenerative braking torque is applied to the right wheel 5b corresponding to the inner side, and the left wheel 5a corresponding to the outer side is applied. Give drive torque. These magnitudes differ depending on the magnitude of the target yaw moment To, and the regenerative braking torque and the drive torque may be equal or different.

  In case C, since the total energy Pr ≧ 0, the drive side requires a larger power than the regeneration side or the same power.

  Here, according to the processing flow shown in FIG. 10, it is determined from where the energy Prl necessary for driving the left wheel 5a is supplied. Furthermore, the total energy Pr required for the calculated rear wheel is supplied according to the state of the battery.

  In Step S140, when Pr ≠ 0, that is, Pr> 0, the torque distribution calculation unit 32F proceeds to Step S141 and inputs the battery state SOC.

  Next, in step S142, it is checked whether or not the battery state SOC is smaller than a certain lower limit threshold SOC_Low. When the battery state SOC is lower than SOC_Low, the process proceeds to step S143. At this time, since electric power cannot be supplied from the battery, power is generated by the front M / G 4 and electric power is supplied to the rear wheel 5a using the energy.

  In step S142, when the battery state SOC is higher than the lower limit value, the process proceeds to step S144, and it is checked whether it is lower than the upper limit value SOC_High.

  If it is determined in step S144 that the battery state SOC is lower than the upper limit value, the process proceeds to step S145.

  In step S145, it is determined what happens to the battery state when the left rear wheel is driven with the torque command value Tmrl * and the right rear wheel is regeneratively braked with the torque command value Tmrr *.

  If it is determined in step S145 that there is no problem in the battery state, the necessary energy Pr may be supplied from the battery 31. In this case, the process proceeds to step S146.

  If there is a problem with the battery state, the process proceeds to step S143 to generate power with the front M / G4.

  If it is determined in step S144 that the battery state SOC exceeds the upper limit value, the battery 31 is nearly fully charged, so the process proceeds to step S146F to actively consume battery power. .

  Next, in step S148, torque command values for the engine 3 and M / G4 at the front are calculated.

  In step S149, a voltage command value to the DC / DC converter 33 is calculated.

  In step S140, when Pr ≠ 0, the drive energy Prl of the AC motor 6a for driving the left wheel 5a and the regenerative energy Prr of the AC motor 6b for regenerative braking of the right wheel are exactly equal. It is not necessary to supply energy from the outside, and the left wheel can be driven using the regenerative energy on the right side.

  In case D, since energy sum Pr <0, energy obtained by regeneration is larger than driving energy. Therefore, in the example of FIG. 7C, the energy Prl required to drive the left wheel 5a can be supplied from the energy Prr obtained by regenerative braking with the right wheel 5b. Therefore, the total energy Pr is energy obtained from the rear wheels and can be supplied to the battery. However, the energy obtained from the rear wheel cannot be supplied depending on the SOC state of the battery 31.

  Here, the surplus energy processing method in case D will be described with reference to FIG.

  In step S150, the torque distribution calculation unit 32F inputs the battery state SOC, and in step S151, checks whether the battery state SOC is lower than the lower limit threshold SOC_Low.

  When the battery state SOC is lower than SOC_Low, it is desirable that the battery is charged. Therefore, the process proceeds to step S152, and the voltage of the DC / DC converter 33 is controlled so that the battery calculates the total energy Pr calculated above.

  In step S151, when the battery state SOC is higher than the threshold value SOC_Low, the process proceeds to step S153 to check whether it is lower than the upper limit SOC_High.

  In step S153, when the battery state SOC is lower than the upper limit value, the state of charge is medium. Therefore, the process proceeds to step S154, and when the left rear wheel 5a is driven with the torque command value Tmrl * and the right rear wheel 5b is regeneratively braked with the torque command value Tmrr *, the state of the battery changes depending on the energy change. Check to determine.

  If it is determined in step S154 that there is no problem in the battery state, the surplus energy Pr may be charged in the battery, and the process proceeds to step S152. If it is determined that there is a problem with the battery state if the surplus energy Pr is charged, the process proceeds to step S155, and surplus energy is consumed using at least one front or rear motor. Similarly, when it is determined in step S153 that the battery state SOC exceeds a certain upper limit value, the process proceeds to step S155, and surplus power is consumed. Here, as a method of consuming by the motor, power is consumed from the battery 31 by consuming it as a loss by the rear AC motor 6a or the AC motor 6b or by driving the front M / G4.

  Next, in step S157, torque command values for the engine 3 and M / G4 at the front are calculated. In step S158, a voltage command value to the DC / DC converter 33 is calculated.

  In case E, since the left and right motor torques are both 0, the total energy Pr of the rear wheels is also 0. Therefore, only the torque distribution of the front engine 3 and the M / G 4 needs to be considered, which will be described later.

Next, the configuration and operation of the motor controllers 14a and 14b and the voltage conversion controller 32 used in the vehicle drive system according to the present embodiment will be described with reference to FIG.
FIG. 12 is a block diagram showing configurations of a motor controller and a voltage conversion controller used in the vehicle drive system according to the first embodiment of the present invention.

  The motor controller 14a calculates a command value for controlling the AC motor 6a and the inverter 8a. The motor controller 14b calculates a command value for controlling the AC motor 6b and the inverter 8b. The voltage conversion controller 16 calculates a command value for controlling the voltage of the DC / DC converter 33.

  Since the motor controller 14a and the motor controller 14b have basically the same configuration, the motor controller 14a will be specifically described here.

  As described above, the HEV controller 32 makes a determination on the state of the battery and obtains the determination result. As a result of the determination, when surplus power is consumed by the motor as in Case B and Case D, a command value calculation different from normal is performed. Here, the torque command for the left wheel will be described as Tr *, and the motor rotation speed of the motor driving the left wheel will be described as ωm.

  In the motor controller 14a, the current command calculation unit 14aX includes a current command value calculation unit 14A, a voltage command calculation unit 14B, a three-phase voltage command calculation unit 14C, and a PWM / rectangular wave signal processing unit 14D.

  The current command value calculation unit 14A calculates a d-axis current command value Id * and a q-axis current command value Iq * for the synchronous motor based on the torque command Trl * and the motor rotation speed ωm. For example, a d-axis current command Id and a q-axis current command Iq table for each operating point of the torque command Tr * and the motor rotation speed ωm are held internally during normal operation and when the motor is consumed, and the operation is performed according to each operating point Then, the d-axis current command value Id * and the q-axis current command value Iq * are determined. As a result, for example, surplus electrical energy corresponding to the total energy Pr consumed by the motor and the inverter at the rear wheel is consumed as heat generated by the AC motor 6a or the AC motor 6b. Therefore, for example, the d-axis current command value Id and the q-axis current command value Iq table are set as a d-axis current command value Id and a q-axis current command value Iq that allow this surplus energy to flow as an invalid current. Specifically, the reactive current is a current that flows in the magnetic flux direction of the AC motor. In addition, there is a method of increasing the loss by shifting the phase of the motor current.

  Next, in order to start motor control with respect to the current command value Id * and the q-axis current command value Iq * determined by the current command value calculation unit 14A, the voltage command calculation unit 14B is calculated by the current command calculation unit 14A. The d-axis voltage command value Vd * and the q-axis voltage command value Vq * are calculated from the d-axis current command value Id * and the q-axis current command Iq *.

  The three-phase voltage command calculator 14C detects the d-axis voltage command value Vd * and the q-axis voltage command value Vq * calculated by the voltage command calculator 14B by a magnetic pole position sensor provided in the AC motor 6. AC voltage command values Vu *, Vv *, and Vw * for the AC motor 6 are calculated using the magnetic pole position θ.

  The PWM / rectangular wave signal processing unit 14D uses an inverter for PWM control or rectangular wave control of the inverter 8 based on the AC voltage commands Vu *, Vv *, Vw * calculated by the three-phase voltage command calculation unit 14C. A drive signal for the internal switching element is generated and output to the inverter 8a.

  The voltage conversion controller 16 is a part that calculates a voltage command value of the DC / DC converter 33, and includes a DC voltage Vdc1 calculation unit 16A, a DC voltage Vdc2 calculation unit 16B, and a DC / DC voltage command value Vdc * calculation unit 16C. And a voltage controller 16D.

  The DC voltage Vdc1 calculation unit 16A is based on the d-axis voltage command value Vd * and the q-axis voltage command value Vq * calculated by the voltage command calculation unit 14B of the motor controller 14a. Vdc1 is calculated as follows. The d-axis voltage command value Vd * and the q-axis voltage command value Vq * are given to the voltage conversion controller 33 via the HEV controller 32. Here, Vdc1 is a value calculated from one of the left and right rear wheel motors (here, the left wheel driving motor 6a).

First, the DC voltage Vdc1 calculating unit 16A calculates the phase voltage V of the AC motor by the following equation (4).

V = (√ (Vd * ² + Vq * ² )) / √3 (4)

Calculate as
Further, the DC voltage command value Vdc1 is calculated from the phase voltage V of the AC motor based on the following formula (5) in the case of PWM control, and in the following formula (6) in the case of rectangular wave control. Calculate based on

Vdc1 = (2√2) · V (5)

Vdc1 = ((2√2) · V) /1.27 (6)

The DC voltage command value Vdc1 calculated here becomes a DC voltage necessary for outputting the left motor torque Tmrl *, for example.

  Similarly, the DC voltage Vdc1 calculation unit 16A determines the other motor (in this case, right side) based on the d-axis voltage command value Vd * and the q-axis voltage command value Vq * calculated by the voltage command calculation unit of the motor controller 14b. A voltage Vdc2 across the DC / DC converter that is at least necessary to output the motor torque Tmrr * of the wheel driving motor 6b) is calculated.

  The DC / DC voltage command value Vdc * calculation unit 16C is based on the DC voltage command value Vdc1 calculated by the DC voltage Vdc1 calculation unit 16A and the DC voltage command value Vdc2 calculated by the DC voltage Vdc2 calculation unit 16B. Necessary DC voltage command value Vdc * is calculated.

  The minimum required voltages Vdc1 and Vdc2 calculated on the left and right sides, respectively, are input to the DC voltage calculated by the DC / DC voltage command value Vdc * calculation unit 16C. The DC voltage command value Vdc * is set to take a value larger than both the DC voltage command value Vdc1 and the DC voltage command value Vdc2. The DC voltage command value Vdc * may be determined in advance according to the operation region and held as a map. By increasing the voltage Vdc *, the current value when driving the motor can be kept small, and a high output can be produced.

  Here, as shown in FIG. 13, when the other wheel is powered by using the energy regeneratively braked by one wheel, as in case 3 and case 4 in (Table 1), the pressure is increased. By flowing a large current instantaneously, an output larger than the continuous rating can be output. For example, the maximum value of the instantaneous maximum torque is set to twice the maximum value of the continuous rated torque. Therefore, it is only necessary to design a motor that can instantaneously generate the maximum torque in such a situation, so that the motor can be reduced in size.

  The voltage control unit 16D calculates the deviation ΔVdc from the voltage command value Vdc * output from the DC / DC voltage command value Vdc * calculation unit 16C and the voltage Vdc that is the output voltage of the DC / DC converter 33. Next, proportional integral (PI) calculation is performed on the obtained deviation ΔVdc, and a duty C1 for setting the switching time of the converter is calculated. The duty C1 signal is supplied to the switching circuit of the DC / DC converter 33, and is feedback-controlled so that Vdc, which is the voltage across the converter, matches the voltage value command value Vdc *. The duty C1 is in the range of 0 ≦ C1 ≦ 1, and for example, when the magnitude of Vdc is boosted with respect to the terminal voltage of the battery 31, control is performed so that 0.5 <C1 <1. When the voltage is lowered with respect to the terminal voltage, control should be performed so that 0 <C1 <0.5. In addition, although the control method in this case is set to PI control, it is not limited to this. Further, if there is a problem in response with only the feedback control system, feed forward compensation may be included.

  According to the present embodiment, the control described above is necessary for generating a yaw moment To that satisfies the driving requirements of the driver and is optimal for vehicle travel, regardless of the state of charge of the battery 31. It becomes possible to output the torques Trl and Trr of the left and right rear wheels.

  Next, the driving force distribution in the front engine 3 and the M / G 4 in step S127 in FIG. 8, step S137 in FIG. 9, step S148 in FIG. 10, and step S157 in FIG. 11 will be described.

  The front wheels 2 can be driven by the engine 3 or the M / G 4. At this time, each of the front wheels 2 is driven in consideration of the efficiency and the state of the battery. First, the amount of driving force or regenerative braking force required for the front wheels 2 is determined by the traveling state calculation unit 32A and the target yaw moment calculation unit 32B in FIG. For example, a method for determining whether to drive the engine 3 or M / G4 when the required torque Tf to the front wheels 2 is given will be described.

  For example, when Tf> 0, that is, when the required torque is the drive torque, if the battery state is close to full charge, the distribution α to M / G4 is increased. Therefore, the torque output from the engine is Te = Tf · (1−α), and the torque driven by M / G4 is Tmf = Tf · α. Here, 0 ≦ α ≦ 1, and it is determined that α increases as the state of the battery approaches full charge. On the other hand, when the battery state SOC is lower than a predetermined value, for example, in a situation where the SOC is lower than 30%, there is not enough energy to drive the M / G4, so all are driven by the engine. Therefore, when α = 1, the front wheels 2 are driven only by M / G4, and when α = 0, they are driven only by the engine 3. In addition, as a method for determining these, as in the case of converting the rear wheel energy, energy conversion necessary for driving the motor may be performed, and a limit value of the drive torque depending on the state of the battery may be set. Is. Further, the amount of driving force to be applied to the engine 3 may be set so that only the torque having the highest efficiency with respect to the rotational speed at that time is output.

  Further, when Tf <0, that is, during braking, the regenerative energy obtained by braking is absorbed as much as possible according to the state of the battery. Therefore, first, the state of the battery is confirmed, and when the battery state SOC is lower than a predetermined value, for example, when the SOC is 30%, it is necessary to charge the battery. Therefore, the battery is charged with energy by regenerating the motor. On the contrary, when the SOC is 70%, it is not necessary to charge any more, and the braking torque is generated by the engine brake or the friction brake. As in the case of driving, the distribution rate of the regenerative torque generated by the engine brake, the friction brake, and the motor may be changed according to the state of charge of the battery. Moreover, the energy conversion obtained by the regenerative braking of the motor is performed, and the limit value of the regenerative braking torque depending on the state of the battery may be set.

  As described above, the torque command value of the front M / G 4 is limited by the storage state of the battery 31. Here, the predetermined torque limit is to prevent a large current from flowing instantaneously through the battery, thereby preventing the battery from being overcharged or overdischarged.

Here, a method for limiting the torque command value of the motor when the battery current is limited by the HEV controller 32 used in the vehicle drive system according to the present embodiment will be described with reference to FIGS.
FIG. 14 is an explanatory diagram of the characteristics of the resistance value with respect to the storage state and temperature of the battery. FIG. 15 is an explanatory diagram of the storage state of the battery and the voltage characteristics of the unit cell. FIG. 16 is a flowchart showing a method for calculating a torque command for the front wheel motor / generator in the torque distribution calculation unit of the HEV controller used in the vehicle drive system according to the first embodiment of the present invention.

  Here, a case where one lithium ion battery is used will be described as an example. As shown in FIG. 14, the characteristics of the lithium ion battery change in resistance value with the change in SOC and temperature. The characteristic of the resistance value varies depending on charging and discharging. Further, the voltage characteristics also change according to the SOC value as shown in FIG. Therefore, the HEV controller 32 holds, as a map, resistance values and voltage characteristics of the single cells at the time of charging and discharging, as shown in FIGS. 14 and 15.

  A process for changing the command value of the motor torque by limiting the current when charging / discharging the battery will be described with reference to FIG.

  In step S160, the HEV controller 32SOC and temperature are input. In step S161, the resistance value Rchg or Rdischg at the time of charging / discharging and the voltage value Vocv of the unit cell are calculated.

Next, in step S162, the allowable charge / discharge current Imax_chg or Imax_dischg is calculated by the following equation (7) or (8).

Imax_chg = {(Vocv_max−Vocv) / Rchg} (7)

Imax_dischg = {(Vocv−Vocv_min) / Rdischg} (8)

Here, Vmax and Vmin represent the maximum voltage value and the minimum voltage value of the unit cell, respectively.

Next, in step S163, a torque command Tmf * to M / G4 is input. In step S164, the energy Pf supplied or consumed by the front M / G 4 is calculated by the following equation (9) or (10).

Pf = Tmf * · ωmf · α (0 <α <1) (9)

Pf = Tmf * · ωmf / α (0 <α <1) (10)

Here, α represents the total efficiency of the front M / G 4 and the inverter 10. As the value of the efficiency α, for example, the efficiency with respect to the rotation speed and torque of the motor is held as a map.

Next, in step S165, the battery voltage Vbatt is input, and in step S166, how much the battery current Ibatt flows when the torque Tmf * is output is calculated by the following equation (11).

Ibatt = Pf / Vbatt (11)

Next, in step S167, the battery current Ibatt is compared with the battery charge / discharge current Imax_chg or Imax_dischg, and whether or not the battery current is within the allowable current value when the torque Tmf is output by M / G4. Determine. If it is within the upper limit value of the allowable charge / discharge current, the process proceeds to step S168, the current limit flag flagIlim = OFF is set, and the torque command value Tmf * to M / G4 is determined as the value Tmf input in step S163. . If the upper limit value of the allowable charge / discharge current is exceeded, the process proceeds to step S169, where the current limit flag flagIlim = ON is set. In step S170, the torque command value for M / G4 and the torque command for the engine 3 are set. Recalculate the value.

  Here, the recalculation method in step S170 will be described using an example.

  First, the case where the energy required at the front is positive (Pf> 0) as in case A or case C, that is, the case where M / G4 is driven will be described. The torque that can be output with M / G4 is (Tmf * Gmf) on the engine shaft with respect to the torque Tf required at the front. Here, Gmf represents the gear ratio between the engine shaft and the motor shaft. Therefore, the remainder (Tf−Tmf * Gmf) obtained by subtracting the torque output from the M / G from the torque required at the front is distributed as the torque output by the engine 3. Therefore, a command for outputting the torque is sent to the ECU 15 by the engine. As described above, in the case of the EV running mode, not on the assumption that the engine is used, it is determined whether the insufficient torque can be output by the rear wheel motor. For example, in step 127 of FIG. 8, if it is determined in the processing from step 121 or step 124, there is a possibility that the rear wheel motor can generate more torque, so the target torque for the rear wheel motor is recalculated. .

  Next, the case where the energy required at the front is negative (Pf <0), that is, the case where regenerative braking of M / G4 is performed as in case B or case D will be described. The torque that can be output by M / G4 is (Tmf * Gmf) on the engine shaft with respect to the braking torque Tf required at the front. Here, Gmf represents the gear ratio between the engine shaft and the motor shaft. Therefore, a braking torque equivalent to the remaining (Tf−Tmf * Gmf) obtained by subtracting the torque output by the M / G from the torque required at the front is output by the mechanical brake. However, when the SOC of the battery is low and regenerative braking is performed by the motor as much as possible to supply energy to the battery, it is determined whether the insufficient torque can be output by the rear wheel motor. For example, in step 137 of FIG. 9, if it has been determined by the processing from step 131 or step 134, the rear wheel motor may be able to generate more torque, so the target torque for the rear wheel motor is recalculated. .

  With the above processing, when driving a motor or generator with a battery, even if the current supplied to the battery or the current taken out from the battery exceeds the allowable value, the torque correction corresponding to each traveling situation is performed. By carrying out, it can implement | achieve, without impairing the running performance of a vehicle.

  As described above, according to this embodiment, the yaw moment of the vehicle can be controlled with high accuracy, and the responsiveness of the vehicle can be improved.

  In addition, it is possible to realize with a small motor by providing means for changing the voltage so that the motor instantaneously outputs the maximum torque.

Next, the overall configuration of the vehicle drive system according to the second embodiment of the present invention will be described with reference to FIG.
FIG. 17 is a system block diagram showing the overall configuration of the vehicle drive system according to the second embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

  The embodiment shown in FIG. 17 is an example when applied to a hybrid vehicle using an engine and a generator at the front and two AC motors for independently driving the left and right at the rear.

  In FIG. 17, the generator 70 is connected to the engine 3 with a dedicated generator 70, and the power generated by the generator 70 is converted into DC power by the power converter 71, and the battery 31. Can be charged.

  In such a configuration, the front is driven only by the engine 3, but when the battery 31 is overdischarged, it can be charged using the generator 70. Moreover, the method of driving the left and right rear wheels independently described in FIGS. 1 to 13 can be similarly applied to the present embodiment.

  Also according to this embodiment, the yaw moment of the vehicle can be controlled with high accuracy and the responsiveness of the vehicle can be improved.

Next, the overall configuration of the vehicle drive system according to the third embodiment of the present invention will be described with reference to FIG.
FIG. 18 is a system block diagram showing the overall configuration of the vehicle drive system according to the third embodiment of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

  The embodiment shown in FIG. 18 is an example when applied to a hybrid vehicle using an engine and a motor / generator at the front, and one motor at the rear and a gear for independently distributing driving power to the left and right.

  In FIG. 18, the rear wheels generate a driving force by the AC motor 6a and distribute the driving force to the left and right by the gear 80 having a structure capable of distributing the driving force to the left and right. As a configuration of the gear 80, for example, a differential as described in NIKKEI MONOZUKURI 14B04.5 may be used.

  With such a configuration, torque distribution to the left and right rear wheels can be realized without mounting two motors at the rear, and the number of motors and inverters to be mounted can be reduced.

  Also according to this embodiment, the yaw moment of the vehicle can be controlled with high accuracy and the responsiveness of the vehicle can be improved.

  Also, the number of motors and inverters to be installed can be reduced.

Next, the overall configuration of the vehicle drive system according to the fourth embodiment of the present invention will be described with reference to FIG.
FIG. 19 is a system block diagram showing the overall configuration of the vehicle drive system according to the fourth embodiment of the present invention. The same reference numerals as those in FIG. 18 denote the same parts.

  The embodiment shown in FIG. 19 is an example when applied to a hybrid vehicle using an engine and a motor / generator at the front, and one motor at the rear and a gear for independently distributing driving power to the left and right.

  In FIG. 19, the rear wheels generate driving force by the AC motor 6a, and distribute the driving force to the left and right by the gear 80 having a structure capable of distributing the driving force to the left and right. As a configuration of the gear 80, for example, a differential as described in NIKKEI MONOZUKURI 14B04.5 may be used.

  With such a configuration, torque distribution to the left and right rear wheels can be realized without mounting two motors at the rear, and the number of motors, inverters and converters to be mounted can be reduced.

Both the front wheel M / G 4 and the rear wheel AC motor 6 a are driven by the battery 31. Therefore, when driving these two motors, in each case of regenerative braking, it is necessary to calculate the sum of the currents taken out from the battery and determine whether or not the current value is an allowable discharge current. About these processes, when the sum total of the battery current is within the allowable current value, it is the same as that by the current value limitation at the time of driving and braking of the M / G 4 according to the third embodiment. As in step S168, the current limit flag flagIlim = OFF may be set. However, if it is determined in step S167 that the allowable current value has been exceeded, the current limit flag flagIlim = ON is set in step S169, and not only the front M / G4 but also the torque command value of the rear wheel motor 6a is re-started. It is necessary to calculate.
Here, an example will be described of a method for recalculating the torque command values for the motors and the engine when the current limitation by the battery current is applied. First, it is assumed that the torque distribution to the front and rear is determined, and Tfront and Trear, respectively.

  First, the case where both the front and rear required torques are positive (Tfront> 0, Trear> 0), that is, the case where the M / G 4 and the AC motor 6a are driven will be described. In this case, if the desired torque is output, the battery discharge current exceeds the allowable value, so it is necessary to reduce the torque used in the motor. Therefore, it can be realized by reducing the total torque required for Tfront and Trear within the allowable battery current range and driving the rest to be compensated by the engine. In this case, if it is better not to change the front and rear torque distribution in consideration of the running performance of the vehicle, the engine can generate more torque than Tfront to generate power, and the rear wheels can be driven with that energy. Is possible. At that time, driving the engine at a high-efficiency operating point is more effective because it increases efficiency.

  Next, a case where regenerative braking torque is output during braking will be described. For example, when the vehicle is traveling straight and it is not necessary to generate a yaw moment, regenerative braking may be performed only with the front wheel M / G4 in terms of charging efficiency. However, when generating the yaw moment according to the running condition of the vehicle, which is the object of this embodiment, torque distribution to the rear wheels is also necessary, so the regenerative braking torque of the rear wheels is not changed as much as possible. Reduce the regenerative braking torque by M / G of the front wheels. However, since the braking force must not be impaired, the torque command value is changed so that the remaining necessary torque is realized by the engine brake or the friction brake.

  Also according to this embodiment, the yaw moment of the vehicle can be controlled with high accuracy and the responsiveness of the vehicle can be improved.

Also, the number of motors, inverters and converters to be installed can be reduced.

1 is a system block diagram showing an overall configuration of a vehicle drive system according to a first embodiment of the present invention. It is a block diagram which shows the structure of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is a flowchart which shows the processing content of the energy conversion part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is explanatory drawing of the electrical storage state of a battery. It is a flowchart which shows the calculation method of the torque command in the torque distribution calculating part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is explanatory drawing of the generation principle of a yaw moment. It is a principle explanatory view of driving force distribution in the vehicle drive system by a 1st embodiment of the present invention. It is a flowchart which shows the calculation method of the torque command in the torque distribution calculating part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is a flowchart which shows the calculation method of the torque command in the torque distribution calculating part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is a flowchart which shows the calculation method of the torque command in the torque distribution calculating part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is a flowchart which shows the calculation method of the torque command in the torque distribution calculating part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is a block diagram which shows the structure of the motor controller and voltage conversion controller which are used for the vehicle drive system by the 1st Embodiment of this invention. It is explanatory drawing of the torque characteristic by the vehicle drive system by the 1st Embodiment of this invention. It is explanatory drawing of the characteristic of the resistance value with respect to the electrical storage state and temperature of a battery. It is explanatory drawing of the electrical storage state of a battery, and the voltage characteristic of a cell. It is a flowchart which shows the calculation method of the torque command of the motor / generator of the front wheel in the torque distribution calculating part of the HEV controller used for the vehicle drive system by the 1st Embodiment of this invention. It is a system block diagram which shows the whole structure of the vehicle drive system by the 2nd Embodiment of this invention. It is a system block diagram which shows the whole structure of the vehicle drive system by the 3rd Embodiment of this invention. It is a system block diagram which shows the whole structure of the vehicle drive system by the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hybrid vehicle 2 ... Front wheel 3 ... Engine 4 ... Motor / generator 5 ... Rear wheel 6 ... AC motor 7 ... Gear 8 ... Inverter 9 ... Clutch 10 ... Inverter 11 ... Electronically controlled throttle 12 ... Accelerator opening sensor 13 ... Axle 14 ... motor controller 15 ... engine control unit 16 ... voltage conversion controller 16A ... DC voltage Vdc1 calculation unit 16B ... DC voltage Vdc2 calculation unit 16C ... DC / DC voltage command value Vdc * calculation unit 16D ... voltage control unit 31 ... battery 32 ... HEV Controller 32A ... running state calculation unit 32B ... target yaw moment calculation unit 32C ... left and right rear wheel target torque calculation unit 32D ... rear wheel motor torque command calculation unit 32E ... energy conversion unit 32F ... torque distribution calculation unit 33 ... voltage conversion means 70 ... Power converter

Claims (7)

Two AC motors that independently drive the left and right rear wheels of the vehicle;
Two inverters respectively driving the two AC motors;
A motor control unit for controlling the two AC motors and the inverter;
A battery that stores electrical energy;
A voltage control means provided between the battery and the two inverters for controlling the input voltage of the two inverters to be raised and lowered;
Traveling state detecting means for detecting the traveling state of the vehicle;
A vehicle drive system for a hybrid vehicle having control means for controlling the inverter, the AC motor, and the generator according to a required torque from the vehicle,
The control means includes the motor, the inverter, and the voltage so as to output an optimum torque to each of the rear wheels according to the remaining amount of the battery and the running state of the vehicle detected by the running state detecting means. A vehicle drive system for controlling a voltage of a control means. The vehicle drive system according to claim 1,
The control means includes
From the torque command value to the two motors for obtaining the optimum torque of the rear wheels, energy calculating means for calculating energy consumed by each motor or energy regenerated,
Battery state detection means for calculating what happens to the state of charge of the battery when an optimum torque is output to each of the rear wheels;
When the energy consumed by the left and right motors calculated by the energy calculating unit is negative at the same time and the battery state detecting unit determines that the battery is overcharged, the reactive current of the AC motor is increased. A vehicle drive system comprising: torque distribution means for reducing regenerative energy and outputting a required torque without the battery being overcharged. The vehicle drive system according to claim 2, wherein
The control means includes
When the energy consumed by the left and right motors calculated by the energy calculating means is positive and negative, the regenerative energy obtained from either the left or right AC motor is used to drive the other AC motor. A vehicle drive system for controlling a voltage of a voltage control means. The vehicle drive system according to claim 3, wherein
The control means includes
The energy consumed by the left and right motors calculated by the energy calculating means is positive and negative, the drive energy of either the left or right AC motor is smaller than the regenerative energy obtained from the other AC motor, and the battery state detecting means When the battery is determined to be over-discharged (when the state of charge of the battery is less than or equal to a predetermined value), the AC motor provided on the front wheels generates power and the power that is insufficient to drive the rear wheels A vehicle drive system for driving the rear wheel AC motor by supplementing. The vehicle drive system according to claim 3, wherein
The control means includes
The energy consumed by the left and right motors calculated by the energy calculating means is positive and negative, the drive energy of either the left or right AC motor is smaller than the regenerative energy obtained from the other AC motor, and the battery state detecting means When the battery is determined to be overcharged (when the state of charge of the battery is equal to or greater than a predetermined value), the rear wheel AC motor is supplemented with power that is insufficient to drive the rear wheel from the battery. The vehicle drive system characterized by driving. The vehicle drive system according to claim 1, further comprising:
An internal combustion engine that supplies driving force to the front wheels;
An inverter that converts the DC power of the battery into AC power;
An AC motor that is driven using the AC power of the inverter, supplies driving force to the front wheels, or is driven by the rotational force of the internal combustion engine, and can generate power;
The control means includes
From the torque command value to the two motors for obtaining the optimum torque of the rear wheel, energy calculating means for calculating energy consumed by each motor or energy regenerated,
Battery state detection means for calculating what happens to the state of charge of the battery when an optimum torque is output to each of the rear wheels;
When the energy consumed by the left and right motors calculated by the energy calculating means is negative at the same time, and the battery state detecting means determines that the battery is overcharged, the output of the internal combustion engine is reduced to prepare for the front wheels. A torque distribution means for driving the AC motor and reducing the regenerative energy by consuming the power of the battery and outputting a required torque without overcharging the battery. A vehicle drive system that is characterized. An AC motor that drives the rear wheels of the vehicle;
An inverter for driving the AC motor;
A motor control unit for controlling the AC motor and the inverter;
A battery that stores electrical energy;
A voltage control means provided between the battery and the inverter for controlling the input voltage of the inverter to be raised and lowered;
Traveling state detecting means for detecting the traveling state of the vehicle;
A vehicle drive system for a hybrid vehicle comprising a control means for controlling the inverter, the AC motor, and the generator according to a required torque from the vehicle,
Provided between the rear wheel and the motor, and distributes the driving force of the motor to the left and right rear wheels, and includes distribution means whose distribution ratio is variable,
The control means controls the distribution ratio by the distribution means so as to output an optimum torque to each wheel of the rear wheel according to the remaining amount of the battery and the running state of the vehicle detected by the running state detecting means. A vehicle drive system characterized by that.

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