WO2013038498A1

WO2013038498A1 - Vehicle and method for controlling vehicle

Info

Publication number: WO2013038498A1
Application number: PCT/JP2011/070843
Authority: WO
Inventors: 上條　祐輔
Original assignee: トヨタ自動車株式会社
Priority date: 2011-09-13
Filing date: 2011-09-13
Publication date: 2013-03-21

Abstract

A vehicle (100) is provided with a motor generator (140) for driving a front wheel (190), a motor generator (146) for driving a rear wheel (195), and an ECU (300) for controlling the motor generators (140, 146). When performing a regeneration operation during an efficiency priority mode selected by a user, the ECU (300) preferentially allocates regeneration torque to the motor generator having higher regeneration efficiency. Thereby, the total regeneration efficiency for the motor generators (140, 146) is increased.

Description

Vehicle and vehicle control method

The present invention relates to a vehicle and a vehicle control method, and more particularly to driving force control of a four-wheel drive vehicle in which front and rear wheels can be driven by an electric motor.

2. Description of the Related Art In recent years, attention has been paid to a vehicle that is mounted with a power storage device (for example, a secondary battery or a capacitor) and travels by using a driving force generated from electric power stored in the power storage device as an environment-friendly vehicle. Such vehicles include, for example, electric vehicles, hybrid vehicles, fuel cell vehicles, and the like.

In these vehicles, when starting or accelerating, a rotating electric machine (which receives electric power from the power storage device to generate a driving force for traveling and generates electric power by regenerative braking during braking to store electric energy in the power storage device ( There is a case where a motor driving device including a motor generator is mounted.

Also, four-wheel drive vehicles have been developed in which front wheels and rear wheels are driven by a rotating electric machine. In such vehicles, driving to front wheels and rear wheels is considered in consideration of efficiency and drivability. Power distribution is required.

Japanese Patent Laid-Open No. 2007-313982 (Patent Document 1) discloses that a fuel efficiency priority mode is selected in a four-wheel drive vehicle in which either a front wheel or a rear wheel is driven by two motors that can be driven independently on the left and right. A configuration is disclosed in which the drive torque distribution to each motor is determined so that the overall efficiency of all the motors that drive the front and rear wheels is the highest.

Japanese Patent Laid-Open No. 2007-168690 (Patent Document 2) discloses that a hybrid vehicle capable of switching between two-wheel drive and four-wheel drive is operated by a user to perform EV travel using only a rotating electric machine as a power source. When the EV switch to be turned on is set, the area for performing the four-wheel drive is reduced and the frequency of operation by the two-wheel drive is increased as compared with the case where the EV switch is off. As a result, power consumption is suppressed and the travel distance in EV travel can be extended.

JP 2007-313982 A JP 2007-168690 A

In such a four-wheel drive vehicle in which front and rear wheels can be driven by motors, when performing regenerative operation during deceleration, the driving force to each motor is taken into account in consideration of regenerative efficiency and running stability (drivability). It is important to allocate.

Generally, regenerative operation using front and rear wheel drive motors tends to stabilize the behavior of the vehicle, but is not necessarily optimal from the standpoint of overall efficiency.

If the regenerative efficiency is made as high as possible, it is possible to recover a large amount of electric power generated in the regenerative operation and to increase the travel distance using the motor.

The present invention has been made to solve such a problem, and an object thereof is a traveling mode in which efficiency is prioritized in a four-wheel drive vehicle in which front and rear wheels can be driven by a plurality of motors. It is to improve the regeneration efficiency when is selected.

A vehicle according to the present invention is a vehicle capable of traveling using electric power, and includes a first rotating electrical machine for driving front wheels, a second rotating electrical machine for driving rear wheels, and first and first rotating electrical machines. And a control device for controlling the two rotating electric machines. When the regeneration operation is performed when the efficiency priority mode is selected by the user, the torque is preferentially distributed to the rotating electrical machine having the high regeneration efficiency among the first and second rotating electrical machines. Further, when performing the regenerative operation when the efficiency priority mode is not selected, the control device distributes more torque to each of the first and second rotating electrical machines than when the efficiency priority mode is selected. Torque is distributed at a predetermined rate according to the driving situation so as to be even.

Preferably, when the regenerative torque is requested such that the torque distributed to the rotating electrical machine having high regenerative efficiency exceeds the predetermined torque, the control device applies a torque exceeding the predetermined torque among the required regenerative torques to the other side. To the rotating electric machine.

Preferably, the vehicle further includes a first inverter for driving the first rotating electrical machine and a second inverter for driving the second rotating electrical machine. The control device shuts down the inverter corresponding to the other rotating electrical machine when all of the required regenerative torque can be distributed to the rotating electrical machine having a high regeneration efficiency.

Preferably, the rotary electric machine with high regeneration efficiency is the first rotary electric machine.
Preferably, when the regenerative power generated by the torque distributed to the rotating electrical machine having a high regenerative efficiency exceeds the reference power, the control device is configured such that the regenerative power by the rotating electrical machine having a high regenerative efficiency does not exceed the reference power Is distributed to the rotating electrical machine with high regeneration efficiency, and the remaining torque of the required regenerative torque is distributed to the other rotating electrical machine.

Preferably, the vehicle further includes an engine that operates in cooperation with the first rotating electric machine to drive the front wheels.

Preferably, the vehicle further includes a switch for the user to select the efficiency priority mode.

A vehicle control method according to the present invention is a control method for a vehicle including a first rotating electrical machine for driving front wheels and a second rotating electrical machine for driving rear wheels. Determining whether or not the efficiency priority mode is selected, and calculating the regeneration efficiency of the first and second rotating electrical machines when performing the regenerative operation when the efficiency priority mode is selected. Prepare. Then, in the control method, when performing the regenerative operation when the efficiency priority mode is selected, the step of preferentially distributing the torque to the rotating electrical machine having high regeneration efficiency among the first and second rotating electrical machines. When the regeneration operation is performed when the efficiency priority mode is not selected, the torque distribution to each of the first and second rotating electrical machines is more even than when the efficiency priority mode is selected. And a step of distributing torque at a predetermined ratio according to the driving situation.

According to the present invention, in a four-wheel drive vehicle in which front and rear wheels can be driven by a plurality of motors, it is possible to improve the regeneration efficiency when a travel mode giving priority to efficiency is selected.

1 is an overall block diagram of a vehicle according to an embodiment. It is a figure for demonstrating the detail of the drive circuit of the rotary electric machine in FIG. It is a figure for demonstrating the outline | summary of the driving force control in this Embodiment. In this Embodiment, it is a functional block diagram for demonstrating the driving force control at the time of the regeneration operation | movement performed by ECU. In this Embodiment, it is a flowchart for demonstrating the detail of the driving force control process at the time of the regeneration operation | movement performed by ECU.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

FIG. 1 is an overall block diagram of vehicle 100 according to the present embodiment. In FIG. 1, the case where the vehicle 100 is a hybrid vehicle including an engine and a rotating electric machine will be described as an example. However, if the front wheels and the rear wheels can be driven by individual rotating electric machines, the configuration of the vehicle 100 is as follows. It is not limited to hybrid vehicles. The configuration of the vehicle 100 includes, in addition to the hybrid vehicle as shown in FIG. 1, an electric vehicle not equipped with an engine, a fuel cell vehicle equipped with a fuel cell, and the like.

Referring to FIG. 1, vehicle 100 includes a power storage device 110, a converter 120,

inverters

130, 135, and 136,

motor generators

140, 145, and 146 that are rotating electrical machines, a power split mechanism 150, and an internal combustion engine. An engine 160,

drive shafts

170 and 175, front wheels 190 and rear wheels 195, a switch 180, an ECU 300 as a control device, and speed reduction mechanisms RD1 and RD2 are provided.

The power storage device 110 is a power storage element configured to be chargeable / dischargeable. The power storage device 110 includes, for example, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a lead storage battery, or a power storage element such as an electric double layer capacitor.

Converter 120 is controlled by control signal PWC from ECU 300, and converts the DC voltage supplied from power storage device 110 into a predetermined voltage. Converter 120 then supplies the converted DC voltage to

inverters

130, 135, and 136. In the case of the regenerative operation, converter 120 converts the electric power generated by

motor generators

140, 145, and 146 into a voltage suitable for charging power storage device 110.

The

inverters

130, 135, and 136 are connected in parallel to the converter 120. Inverter 130 and inverter 135 are controlled by control signals PWI1 and PWI2 from ECU 300, respectively, to drive motor generator 140 and motor generator 145. Inverter 136 is controlled by control signal PWIR from ECU 300 to drive motor generator 146. In the following description,

inverters

130, 135, and 136 are also referred to as “INV1”, “INV2”, and “INVR”, respectively, and

motor generators

140, 145, and 146 are referred to as “MG1”, “MG2”, and “MGR”, respectively. Also called.

Motor generators

140, 145, and 146 are AC rotating electric machines, for example, permanent magnet type synchronous motors having a rotor in which permanent magnets are embedded.

The

motor generators

140 and 145 are coupled to each other by a power split mechanism 150 that typically includes a planetary gear. In the hybrid vehicle as shown in FIG. 1, engine 160 is also coupled to

motor generators

140 and 145 by power split mechanism 150.

Motor generators

140 and 145 and engine 160 are cooperatively controlled by ECU 300, and the driving force from

motor generators

140 and 145 and the driving force from engine 160 are transmitted to front wheels 190 via reduction mechanism RD1 and driving shaft 170. Is transmitted to. Furthermore,

motor generators

140 and 145 can generate electric power by rotation of engine 160 or rotation of front wheels 190, and can use this generated electric power to charge power storage device 110.

In the present embodiment, motor generator 145 (MG2) is used exclusively as an electric motor for driving front wheels 190, and motor generator 140 (MG1) is used exclusively as a generator driven by engine 160. Motor generator 140 (MG1) is used to crank the crankshaft of engine 160 when engine 160 is started.

The output shaft of the motor generator 146 (MGR) is connected to the rear wheel 195 via the speed reduction mechanism RD2 and the drive shaft 175, and drives the rear wheel 195. The vehicle 100 is a so-called four-wheel drive vehicle that can travel by driving the front wheels 190 and the rear wheels 195 as described above.

FIG. 1 shows an example of a configuration in which two front-wheel motor generators and one rear-wheel motor generator are provided, but the front wheels and the rear wheels are each driven by a separate motor generator. The number of motor generators is not limited to this as long as it is configured. For example, the front-wheel drive system and the rear-wheel drive system shown in FIG. 1 are interchanged, the front-wheel drive system (

motor generators

140, 145 and engine 160) drives the rear wheels 195, and the rear-wheel drive system ( The motor generator 146) may drive the front wheels 190. Alternatively, there may be one or more motor generators in the front wheel drive system. Furthermore, in the drive system for the rear wheels, a configuration may be adopted in which separate motor generators are provided on the left and right drive wheels.

The switch 180 is a switch that is operated by the user to select a travel mode in which efficiency is emphasized for the purpose of energy saving (hereinafter also referred to as “fuel economy priority mode”). Switch 180 outputs selection signal ECO to ECU 300. Specifically, when the fuel efficiency priority mode is selected, the selection signal ECO is set to ON and output, and when the fuel efficiency priority mode is not selected, the selection signal ECO is set to OFF and output. . The “fuel efficiency priority mode” in the present embodiment corresponds to the “efficiency priority mode” in the present invention.

ECU 300 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer (not shown in FIG. 1). The ECU 300 inputs a signal from each sensor and outputs a control signal to each device. 100 and each device are controlled. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

ECU 300 calculates the SOC of power storage device 110 based on detected values of voltage VB and current IB from a voltage sensor and a current sensor (both not shown) provided in power storage device 110. ECU 300 controls engine 160 using control signal DRV.

In FIG. 1, one control device is provided as the ECU 300, but for each function, such as a control device for the converter 120, the

inverters

130, 135, and 136, a control device for the power storage device 110, and the like. Or it is good also as a structure which provides a separate control apparatus for every control object apparatus.

Next, details of the drive circuit of the

motor generators

140, 145 and 146 in FIG. 1 will be described with reference to FIG.

Referring to FIGS. 1 and 2, power storage device 110 is connected to converter 120 through power lines PL1 and NL1.

The relay included in system main relay (SMR) 115 has one end connected to the positive terminal and the negative terminal of power storage device 110, and the other end connected to power lines PL1 and NL1. SMR 115 switches between power supply and cutoff between power storage device 110 and converter 120 based on control signal SE <b> 1 from ECU 300.

Converter 120 includes a reactor L1, switching elements Q1 and Q2, and diodes D1 and D2. Switching elements Q1, Q2 are connected in series between power lines PL2 and NL1. Switching elements Q1, Q2 are controlled by a switching control signal PWC from ECU 300.

In the present embodiment, for example, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, a power bipolar transistor, or the like can be used as the switching element. Anti-parallel diodes D1 and D2 are arranged for switching elements Q1 and Q2. Reactor L1 is connected between a connection node of switching elements Q1, Q2 and power line PL1. That is, converter 120 forms a so-called chopper circuit.

The converter 120 is basically controlled so that the switching elements Q1 and Q2 are turned on and off in a complementary manner within each switching period. During the step-up operation, converter 120 converts DC voltage VL supplied from power storage device 110 into DC voltage VH (this DC voltage corresponding to the input voltage to

inverters

130, 135, and 136 is hereinafter also referred to as “system voltage”). Boost the pressure. This boosting operation is performed by supplying the electromagnetic energy accumulated in reactor L1 during the ON period of switching element Q2 to power line PL2 via switching element Q1 and antiparallel diode D1.

Further, converter 120 steps down DC voltage VH to DC voltage VL during the step-down operation. This step-down operation is performed by supplying the electromagnetic energy stored in reactor L1 during the ON period of switching element Q1 to power line NL1 via switching element Q2 and antiparallel diode D2. The voltage conversion ratio (the ratio of VH and VL) in these step-up and step-down operations is controlled by the on-period ratio (duty ratio) of the switching elements Q1 and Q2 in the switching period. Note that VH = VL (voltage conversion ratio = 1.0) can be obtained by switching the switching element Q1 on and fixing the switching element Q2 off.

Capacitor C1 is provided between power lines PL1 and NL1, and reduces voltage fluctuation between power lines PL1 and NL1. Voltage sensor 215 detects voltage VL applied to capacitor C1 and outputs the detected value to ECU 300.

The capacitor C2 is provided between the power lines PL2 and NL1, and reduces voltage fluctuation between the power lines PL2 and NL1. Voltage sensor 210 detects voltage VH applied to capacitor C2 and outputs the detected value to ECU 300.

The inverter 130 includes a U-phase upper and lower arm 131, a V-phase upper and lower arm 132, and a W-phase upper and lower arm 133 provided in parallel between the power lines PL2 and NL1. Each phase upper and lower arm includes a switching element connected in series between power lines PL2 and NL1. For example, U-phase upper and lower arms 131 include switching elements Q3 and Q4, V-phase upper and lower arms 132 include switching elements Q5 and Q6, and W-phase upper and lower arms 133 include switching elements Q7 and Q8. Antiparallel diodes D3 to D8 are connected to switching elements Q3 to Q8, respectively. Switching elements Q3-Q8 are controlled by a control signal PWI1 from ECU 300.

The motor generator 140 is typically a three-phase permanent magnet type synchronous motor, and one end of three coils in the U, V, and W phases is commonly connected to a neutral point. Further, the other end of each phase coil is connected to a connection node of two switching elements in each phase upper and lower arms 131 to 133.

The motor generator 140 is provided with a speed sensor 200 for detecting the rotational speed of the motor generator 140. Speed sensor 200 detects rotational speed NMG1 of motor generator 140 and outputs the detected value to ECU 300. Instead of speed sensor 200, a rotation angle sensor (not shown) for detecting the rotation angle of motor generator 140 may be provided. In this case, ECU 300 is detected by the rotation angle sensor. A rotation speed NMG1 is calculated by calculation based on the rotation angle θ1.

The inverter 135 for driving the motor generator 145 and the inverter 136 for driving the motor generator 146 are connected to the power lines PL2 and NL1 in parallel with the inverter 130.

Since the detailed configuration of the

inverters

135 and 136 is the same as that of the inverter 130, the details thereof are not described, and the detailed description thereof will not be repeated.

In FIG. 2, all of the

inverters

130, 135, and 136 are connected in parallel to the converter 120. For example, for the rear-wheel inverter 136, the converter 120 is You may make it connect directly to electric power lines PL1 and NL1 without going through.

The

motor generators

145 and 146 are also provided with

rotational speed sensors

205 and 206, respectively.

Rotational speed sensors

205 and 206 output detected rotational speeds NMG2 and NMGR to ECU 300, respectively.

ECU 300 receives a required torque TR determined based on an operation of an accelerator pedal (not shown) by a user, etc., and

motor generators

140, 145, 146 and an engine based on the traveling state, traveling mode, SOC, and the like of vehicle 100. 160 driving torque is determined. ECU 300 generates control signals PWC, PWI1, PWI2, PWIR, DRV according to the determined driving torque, and drives

motor generators

140, 145, 146 and engine 160.

In such a four-wheel drive vehicle, when performing a regenerative operation at the time of deceleration, it is common to perform regenerative braking with both front wheels and rear wheels with emphasis on drivability.

In the case of two-wheel drive (front wheel drive, rear wheel drive) that drives only the front wheel or the rear wheel, if the drive wheel is locked during the sudden deceleration of the vehicle, the steering performance and the vehicle stability are reduced. There is a tendency for turning performance to deteriorate due to oversteer or understeer during turning. On the other hand, in four-wheel drive, steering force in two-wheel drive is used to show intermediate characteristics between front-wheel drive and rear-wheel drive by distributing drive force (regenerative braking force) to both front and rear wheels. As a result, the vehicle stability is relatively improved.

However, it may not always be optimal from the viewpoint of energy efficiency to distribute the regenerative braking force to both the front and rear wheels. In hybrid vehicles and electric vehicles that use a driving force (braking force) generated by a motor generator, the power generated by regenerative braking is stored in a power storage device, and the generated power is used to further drive to increase energy efficiency. Yes. Therefore, in order to improve the energy efficiency at the time of traveling and to increase the distance that can be traveled by electric power as much as possible, it is one of the measures to improve the power generation efficiency (regenerative efficiency) at the time of regenerative braking.

Therefore, in the present embodiment, when the fuel efficiency priority mode is selected, when performing the regenerative operation, the driving force that preferentially distributes the regenerative torque to the motor generator with high regenerative efficiency to improve the energy efficiency. Take control.

FIG. 3 is a diagram for explaining an outline of the driving force control in the present embodiment. FIG. 3 is a graph showing an example of the relationship between the rotational speed and torque of the motor generator and the efficiency. The motor generator can take an operating point within a range surrounded by the coordinate axis and the curve W10.

Referring to FIG. 3, the horizontal axis of FIG. 3 shows the rotation speed of the motor generator, and the vertical axis shows the regenerative torque. The broken contour lines in FIG. 3 indicate the regeneration efficiency of the motor generator. In FIG. 3, the regeneration efficiency increases in the direction of arrows AR1, AR2, AR3. That is, in FIG. 3, the regeneration efficiency is highest in the region inside the contour line indicated by DM1.

Here, for ease of explanation, it is assumed that the reduction ratios of the front wheels and the rear wheels are the same, and both the front-wheel and rear-wheel motor generators have the characteristics shown in FIG. At this time, when the driving force control of the present embodiment is not applied, the operation points of the front wheels and the rear wheels when the rotational speed is Nm are point P11 and point P10 in FIG. 3, respectively. In this case, neither the front-wheel nor the rear-wheel motor generator is an operating point at which the regeneration efficiency is optimal.

On the other hand, when the present embodiment is applied, the regenerative torque is preferentially distributed to a motor generator (for example, front wheel) with high regenerative efficiency. All of the regenerative torque to be distributed to the motor generator on the front wheel side is distributed. Then, the operating point of the motor generator on the front wheel side is a point P20 in FIG. 3, and the regeneration efficiency of the motor generator on the front wheel side is improved, and the efficiency is improved as a whole.

FIG. 4 is a functional block diagram for explaining the driving force control during the regenerative operation performed by the ECU 300 in the present embodiment. Each functional block described in the block diagram illustrated in FIG. 4 is realized by hardware or software processing by ECU 300.

1 and 4, ECU 300 includes an efficiency calculation unit 310, a torque setting unit 320, a storage unit 330, and a drive control unit 340.

The efficiency calculation unit 310 receives the requested torque TR from the user and the rotational speeds NMG1, NMG2, NMGR of the

motor generators

140, 145, 146. Based on these pieces of information, the efficiency calculation unit 310 uses the map as shown in FIG. 3 stored in the storage unit 330 to distribute the drive torque to the

motor generators

140, 145, and 146 during the regenerative operation, The regeneration efficiency EFF_Fr by the drive system of the front wheels 190 and the regeneration efficiency EFF_Rr by the drive system of the rear wheels 195 in the case of each distribution pattern are calculated. Then, the efficiency calculation unit 310 outputs the calculated regeneration efficiencies EFF_Fr and EFF_Rr to the torque setting unit 320.

The torque setting unit 320 receives the regeneration efficiency EFF_Fr, EFF_Rr from the efficiency calculation unit 310. Torque setting unit 320 receives selection signal ECO from switch 180 and signal RGE indicating a regenerative operation from a host ECU (not shown).

The torque setting unit 320 determines torque distribution to the

motor generators

140, 145, 146 and the engine during the regenerative operation based on whether the fuel efficiency priority mode is set by the selection signal ECO. When the fuel efficiency priority mode is set, the torque setting unit 320 determines a torque distribution pattern that preferentially distributes torque to those with high efficiency based on the regeneration efficiency EFF_Fr, EFF_Rr. Then, torque command values TMG1, TMG2, and TMGR corresponding to the determined pattern are calculated using the map stored in storage unit 330.

On the other hand, when the fuel efficiency priority mode is not set, torque distribution to

motor generators

140, 145, 146 and the engine is performed in accordance with the driving conditions so that the driving torques of front wheel 190 and rear wheel 195 are substantially equal. To decide.

At this time, torque setting unit 320 also calculates torque command value TE distributed to engine 160 and boost target voltage command value VR of converter 120. Then, torque command values TMG1, TMG2, and TMGR for each motor generator, torque command value TE for engine 160, and boost target voltage command value VR for converter 120 are output to drive control unit 340.

The drive control unit 340 receives each command value from the torque setting unit, the rotational speeds NMG1, NMG2, NMR of each motor generator from the speed sensor 200, and the detection value VH from the voltage sensor 210. The drive control unit 340 calculates control signals PWC, PWI1, PWI2, PWR, and DRV based on these pieces of information. Drive control unit 340 drives converter 120,

inverters

130, 135, 136, and engine 160 using these control signals.

FIG. 5 is a flowchart for explaining the details of the driving force control process during the regenerative operation executed by the ECU 300 in the present embodiment. Each step in the flowchart shown in FIG. 5 is realized by executing a program stored in advance in ECU 300 at a predetermined cycle. Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing.

Referring to FIGS. 1 and 5, ECU 300 determines in step (hereinafter, step is abbreviated as S) 100 whether or not a regenerative operation is currently being performed based on signal RGE.

If the regenerative operation is not being performed (NO in S100), the process is not executed, and ECU 300 ends the process.

If the regenerative operation is being performed (YES in S100), the process proceeds to S110, and ECU 300 next determines whether or not the fuel efficiency priority mode is selected based on selection signal ECO from switch 180. judge.

If the fuel efficiency priority mode is selected (YES in S110), the process proceeds to S120, and ECU 300 calculates regenerative efficiencies EFF_Fr and EFF_Rr for each torque distribution pattern to the drive systems for the front wheels and the rear wheels. To do. In the configuration of FIG. 1, in the drive system for the front wheels, the regeneration operation by the rotation of the drive wheels is performed by the motor generator 145 (MG2), so the regeneration efficiency EFF_Fr of the front wheels is substantially equal to the efficiency of MG2. Become. Further, in the calculation of the regeneration efficiency, the reduction ratios GR1 and GR2 by the reduction mechanisms RD1 and RD2 are also taken into consideration.

In the configuration in which the main driving force is generated by the front wheel drive system as shown in FIG. 1, the motor generator 145 (MG2) has a higher rated output than the motor generator 146 (MGR) on the rear wheel side. In addition, since the load on the front wheels is larger than that on the rear wheels when decelerating, the operating point at which the efficiency of the motor generator 145 (MG2) on the front wheels is increased to increase the total regeneration efficiency. Therefore, it is preferable that the motor generator 145 (MG2) performs the regeneration operation preferentially. When the motor generator 145 (MG2) becomes the optimum operating point and the regenerative torque is still necessary, the ECU 300 uses the rear wheel side motor generator 146 (MGR) for the remaining regenerative torque. Control to generate by regenerative operation.

In the case where the power generated by the front wheel side motor generator 145 (MG2) exceeds a predetermined reference power, the reference power is not limited even if the efficiency of the front wheel side motor generator 145 (MG2) is not the optimum operating point. The torque distribution to the motor generator 145 (MG2) on the front wheel side may be determined so as not to exceed.

Then, in S130, ECU 300 calculates a torque distribution pattern that increases the regenerative efficiency of the entire motor generator based on the calculated regenerative efficiencies EFF_Fr and EFF_Rr.

As a result of torque distribution, there may be a distribution in which regenerative operation is performed only by the motor generator 145 on the front wheel side. In this case, as a result, the regenerative operation is not performed in the motor generator 146 on the rear wheel side. At this time, it is possible to perform zero torque control for motor generator 146 (MGR), but it is also possible to completely shut down inverter 136. By shutting down the inverter, power used for switching control for zero torque control can be saved, and the efficiency can be further increased, which is more preferable.

Therefore, in S140, ECU 300 determines whether or not the distribution ratio of the regeneration torque on the front wheel side is 100% based on the torque distribution result set in S130.

If the distribution ratio of the regeneration torque on the front wheel side is 100% (YES in S140), the process proceeds to S150, ECU 300 shuts off rear wheel inverter 136 (INVR), and the process proceeds to S160. . ECU 300 controls the inverter so as to perform a regenerative operation using only motor generator 145 on the front wheel side.

When the distribution ratio of the regeneration torque on the front wheel side is not 100% (NO in S140), the process of S150 is skipped, and ECU 300 controls the inverter in S160 according to the torque distribution set in S130.

On the other hand, if the fuel economy priority mode is not selected in S110 (NO in S110), the process proceeds to S170, and ECU 300 performs regenerative torque distribution giving priority to running stability (drivability).

As described above, when the regenerative torque is preferentially distributed to the front wheels, a large braking force is applied to the front wheels, which are the steered wheels, so that the front wheels are likely to be locked, and understeer during turning is increased. As a result, drivability may deteriorate. Therefore, as the regenerative torque distribution in S170, for example, the braking force generated by the front wheel side motor generator 145 and the rear wheel side motor generator 146 is more even than that in the fuel efficiency priority mode. A method of allocating the regenerative torque to both the front wheels and the rear wheels at a predetermined ratio according to the driving situation is conceivable. In this case, the regenerative torque to be distributed is not limited to the case where the ratio of the front wheels and the rear wheels is completely equal, such as 50:50, and the regenerative torque distributed to the front wheels and the rear wheels than in the fuel efficiency priority mode. If the difference is small, for example, a distribution such as 40:60 or 70:30 is included.

Then, in S160, ECU 300 controls the inverter according to the torque distribution set in S170.

Although not shown in FIG. 5, for example, when there is a high possibility that the drivability is deteriorated due to sudden deceleration, for example, even when the fuel efficiency priority mode is selected, Regenerative torque may be distributed to both the front wheels and the rear wheels so as to ensure running stability.

By performing control according to the above-described processing, in a vehicle in which front wheels and rear wheels are driven by a plurality of different motor generators, when performing a regenerative operation when the fuel efficiency priority mode is selected, a plurality of motor generators Torque distribution is performed to increase the regeneration efficiency. Specifically, the regenerative torque is preferentially distributed to the motor generator on the front wheel side with high regenerative efficiency. Further, when the regenerative torque is distributed only to the motor generator on the front wheel side, the inverter that drives the motor generator on the rear wheel side is shut off. By doing so, when the fuel efficiency priority mode is selected, it is possible to receive as much generated power as possible by efficiently performing the regenerative operation, and to increase the travel distance using the power. .

On the other hand, when the fuel efficiency priority mode is not selected, torque distribution can be performed with priority given to drivability, and driving stability can be ensured.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

100 vehicle, 110 power storage device, 115 SMR, 120 converter, 130, 135, 136 inverter, 131 U-phase upper and lower arms, 132 V-phase upper and lower arms, 133 W-phase upper and lower arms, 140, 145, 146 motor generator, 150 power split mechanism , 160 engine, 170, 175 drive shaft, 180 switch, 190 front wheel, 195 rear wheel, 200, 205, 206 speed sensor, 210, 215 voltage sensor, 300 ECU, 310 efficiency calculation unit, 320 torque setting unit, 330 storage unit 340 drive control unit, C1, C2 capacitor, D1 to D8 diode, L1 reactor, NL1, PL1, PL2 power line, Q1 to Q8 switching element, RD1, RD2 reduction mechanism.

Claims

A vehicle that can run using electric power,
A first rotating electrical machine (145) for driving the front wheels (190);
A second rotating electrical machine (146) for driving the rear wheels (195);
A control device (300) for controlling the first and second rotating electric machines (145, 146),
When performing the regenerative operation when the efficiency priority mode is selected by the user, the control device (300) is selected as a rotating electric machine having a high regenerative efficiency among the first and second rotating electric machines (145, 146). On the other hand, when the torque is preferentially distributed and the regenerative operation is performed when the efficiency priority mode is not selected, the first and second rotating electrical machines (when compared with the case where the efficiency priority mode is selected) 145, 146) a vehicle that distributes torque at a predetermined rate according to the driving situation so that the torque distribution to each of 145, 146) becomes more even.
The control device (300) exceeds the predetermined torque of the required regenerative torque when a regenerative torque is required such that a torque distributed to the rotating electrical machine having high regenerative efficiency exceeds a predetermined torque. The vehicle according to claim 1, wherein the generated torque is distributed to the other rotating electrical machine.
A first inverter (135) for driving the first rotating electrical machine (145);
A second inverter (136) for driving the second rotating electrical machine (146),
The vehicle according to claim 1, wherein the control device (300) shuts down an inverter corresponding to the other rotating electrical machine when all of the required regenerative torque can be distributed to the rotating electrical machine having a high regeneration efficiency.
The vehicle according to claim 1, wherein the rotating electric machine with high regeneration efficiency is the first rotating electric machine (145).
When the regenerative power generated by the torque distributed to the rotating electrical machine with high regeneration efficiency exceeds the reference power, the regenerative power by the rotating electrical machine with high regeneration efficiency exceeds the reference power. 2. The vehicle according to claim 1, wherein a torque that does not occur is distributed to the rotating electrical machine having a high regeneration efficiency, and a remaining torque of the required regenerative torque is distributed to the other rotating electrical machine.
The vehicle according to claim 1, further comprising an engine (160) that operates in cooperation with the first rotating electrical machine (145) to drive the front wheels (190).
The vehicle according to claim 1, further comprising a switch (180) for a user to select the efficiency priority mode.
A vehicle control method including a first rotating electrical machine (145) for driving a front wheel (190) and a second rotating electrical machine (146) for driving a rear wheel (195),
Determining whether an efficiency priority mode is selected by the user;
Calculating the regeneration efficiency of the first and second rotating electrical machines (145, 146) when performing the regeneration operation when the efficiency priority mode is selected;
When performing the regenerative operation when the efficiency priority mode is selected, the torque is preferentially distributed to the rotary electric machine having the high regeneration efficiency among the first and second rotary electric machines (145, 146). Steps,
When performing the regenerative operation when the efficiency priority mode is not selected, torque is distributed to each of the first and second rotating electric machines (145, 146) compared to when the efficiency priority mode is selected. And a step of distributing torque at a predetermined rate according to the driving situation so that is more even.