JP2018098985A - Electric vehicle and motor output control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle performing torque control and clutch control of each motor for wheel driving, so as to reduce energy loss of a vehicle to minimum, and a motor output control method thereof.SOLUTION: An electric vehicle 10 comprises: a motor 15 for front wheel driving and a motor 16 for rear wheel driving; a control part 25 for controlling an output torque of the motors for wheel driving; a clutch 22 for front wheel for disconnecting power transmission between front wheels 11 and the motor for front wheel driving; and a clutch 23 for rear wheel for disconnecting power transmission between rear wheels 12 and the motor for rear wheel driving. The control part controls torques of the motors for front/rear wheel driving and controls clutch, so that, energy loss total amount which is a sum of energy loss in a power transmission path 17 between the motor for front wheel driving and front wheels, energy loss on the motor for rear wheel driving, and energy loss on a power transmission path 18 between the motor for rear wheel driving and the rear wheels becomes minimum.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor that drives front wheels and rear wheels, and an electric vehicle that performs torque control and clutch control of the motor in consideration of energy loss in a power transmission path, and a motor output control method thereof.

  In this type of electric vehicle, there is disclosed an electric vehicle that separately includes a motor that drives front wheels and a motor that drives rear wheels, and controls the torque of each motor according to the vehicle speed (see Patent Document 1).

Japanese Patent Laid-Open No. 5-328541

  The electric vehicle described in Patent Document 1 controls the number of motors driven and the drive current in accordance with desired torque and vehicle speed in an electric vehicle in which a plurality of drive wheels (front wheels, rear wheels) are rotated by a plurality of motors. It is what I did.

  However, in this electric vehicle, no consideration is given to the energy loss of each motor driven by the output power of the battery or the energy loss of the power transmission mechanism in which the driving force of each motor is transmitted to the wheels. There was a problem in terms of efficiency.

  The present invention has been made in consideration of the above-described circumstances. The torque control of each motor and each motor and each power transmission mechanism are connected and disconnected so that the total energy loss of the motor and the power transmission mechanism is minimized. An object of the present invention is to provide an electric vehicle and a motor output control method thereof in which clutch control is performed and energy efficiency of driving and regeneration is improved.

  In order to solve the problems described above, the present invention provides a first wheel motor capable of transmitting a driving force to a first wheel, a second wheel motor capable of transmitting a driving force to a second wheel, A first wheel for connecting and disconnecting power transmission between the first wheel and the first wheel motor in an electric vehicle comprising: a control unit that controls output torque of the first wheel motor and the second wheel motor. And a second wheel clutch for connecting and disconnecting power transmission between the second wheel and the second wheel motor, and the control unit includes an energy loss in the first wheel motor and the second wheel clutch. Energy loss in the power transmission path between the one-wheel motor and the first wheel, energy loss in the second wheel motor, and power between the second wheel motor and the second wheel Energy loss in the transmission path and The torque control of the first wheel motor and the second wheel motor and the clutch control of the first wheel clutch and the second wheel clutch are performed so that the total energy loss which is the sum is minimized. An electric vehicle characterized by being configured.

  Further, in order to solve the above-described problem, the present invention obtains the required power of the vehicle (= requested torque × wheel rotational speed) from the vehicle operation information, the vehicle information, the required torque map of the vehicle, and the rotational speed of the wheel. A step of calculating, a step of sequentially determining a drive distribution ratio of both motors within a drive distribution range of the first wheel motor and the second wheel motor, and input of the required power of the vehicle and the required drive distribution ratio The motor drive distribution calculation processing unit performs calculation processing using the motor energy loss map and the transmission energy loss map, calculates and stores the total energy loss of the motor and transmission in the required drive distribution ratio, Within the drive distribution range of the first wheel motor and the second wheel motor, the drive distribution ratio of both motors is not a predetermined distribution ratio. Sequentially changing the motor drive distribution calculation processing unit to perform a series of the calculation processing calculations and calculating and storing the total energy loss of the motor and the transmission at each drive distribution ratio. The motor of the electric vehicle is characterized in that the motor output and the clutch connection / disengagement control are performed based on the smallest energy loss total among the stored energy loss totals of the plurality of motors and transmissions by repeating the arithmetic processing calculation of This is an output control method.

  The electric vehicle according to the present invention considers the energy loss of each wheel motor and the power transmission path for driving the first wheel and the second wheel, respectively, so that the total energy loss is minimized. The torque control of the motor and the clutch control for connecting / disconnecting the power transmission path can be performed to increase the energy efficiency of driving and regeneration, and the efficiency can be improved.

The layout block diagram which shows one Embodiment of the electric vehicle which concerns on this invention. The block diagram which shows the outline | summary of the vehicle control of the control part with which an electric vehicle is equipped. The graph which shows the required torque map of the vehicle requested | required of an electric vehicle. The block diagram which shows the example of a calculation process of the motor A, B drive distribution calculation process part with which the control part of an electric vehicle is equipped. (A) is a figure which shows the energy loss map of the motor A, (B) is a figure which shows the energy loss map of the motor B. (A) is a figure which shows the energy loss map of the transmission A, (B) is a figure which shows the energy loss map of the transmission B. The flowchart figure which shows the motor output control and clutch (open / close) control of an electric vehicle.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a layout configuration diagram showing an embodiment of an electric vehicle according to the present invention.

  The electric vehicle 10 is an EV (Electric Vehicle) vehicle that travels by motor drive using electricity as an energy source. The electric vehicle 10 includes a front wheel drive motor 15 (hereinafter referred to as motor A) and a rear wheel drive motor 16 (hereinafter referred to as motor B) on the front, rear, left and right of the drive shafts 13 and 14 of the front wheels 11 and rear wheels 12. Are arranged respectively. Motor A and motor B are connected to drive shafts 13 and 14 via transmissions 17 and 18, respectively, to drive the front wheels 11 and the rear wheels 12 to travel.

  The transmissions 17 and 18 constitute a power transmission path (drive train) that transmits the motor driving force of the motor A and the motor B to the front wheels 11 and the rear wheels 12 via the drive shafts 13 and 14, respectively. Each transmission 17, 18 includes speed reducers 20, 21, clutch mechanisms 22, 23, and the like. The speed reducers 20 and 21 amplify the torques of the motors A and B. By reducing the rotational speed and transmitting them to the front wheels 11 and the rear wheels 12, the torque is amplified and a large driving force is generated. Yes. Clutch mechanisms 22 and 23 (hereinafter referred to as clutch A and clutch B) perform clutch control for separating and connecting motor A and motor B with drive shafts 13 and 14, and the type of clutch is a wet clutch. And dry clutch.

  In addition, the electric vehicle 10 includes a control unit 25 such as an ECM (Electric Control Module), and the operation information of the driver such as the accelerator 26 and the brake 27 and vehicle information such as the vehicle speed are taken into the control unit 25. Therefore, it is processed. Specifically, an accelerator pedal operation amount is detected by a sensor that detects an accelerator pedal depression angle (accelerator angle), and a brake pedal operation amount is detected by a sensor that detects a brake pedal depression angle (brake angle). Further, vehicle speed information is detected by a speed sensor (not shown) that detects the vehicle speed of the vehicle. The detected accelerator pedal operation amount, brake pedal operation amount, and vehicle speed information are input to the control unit 25 and processed. An output signal from the control unit 25 is output to the inverter 28 as a motor torque command for the motors A and B and an opening / closing command for the two clutches.

  The inverter 28 controls the electric energy charged in the battery 29 of the secondary battery from a power source (not shown) outside the vehicle and transmits it to the motor A and the motor B as power. Specifically, the inverter 28 converts a direct current from the battery 29 into an alternating current and sends it to the motor A and the motor B. The inverter 28 adjusts the amount of current and controls the outputs of the motor A and the motor B. doing. The inverter 28 may be composed of a power control unit. The battery 29 includes a battery pack in which lithium ion batteries and nickel metal hydride batteries are collected and connected.

  By the way, the electric vehicle 10 has different horsepower (required power) required for the vehicle at the time of starting, running, etc., and it is necessary to change the rotation speed in order to apply a required rotational force (torque) to the wheels depending on the situation. As shown in FIG. 2, the control unit 25 of the electric vehicle 10 includes vehicle speed information a that is vehicle information, an accelerator pedal operation amount b that is driver's accelerator pedal operation information, and a brake pedal operation amount that is brake pedal operation information. c is adopted to perform torque control of motor A and motor B and clutch (open / close) control of two clutches (clutch A and clutch B).

The control unit 25 is configured as shown in FIG. The control unit 25 receives the vehicle speed information a, the accelerator pedal operation amount b, and the brake pedal operation amount c, and calculates the required power Pt required for the vehicle, and the drive distribution of the motor A and motor B. Motor A and B drive distribution range determining unit 34 for determining the ratio, and motor A and motor B drive distribution ratio α _n from motor A and motor B drive distribution range determining unit 34 and vehicle from required power calculating unit 33 Motor A and B drive distribution calculation processing unit 35 that calculates the required power PA and PB at the drive distribution ratio α of the motor A and motor B with the least energy loss. And the required powers PA and PB of the motor A and the motor B that have been processed are output as the optimum output signal d, and the motor A based on the output signal d is output. The optimum torque and the motor B, motor A and motor B and the device commands _e of the clutch A and clutch _{B (e 1, e 2)} , with each device command conversion unit 36 for converting the _{f (f} 1, _{f 2)} Is provided.

Each device command conversion unit 36 is based on the optimum torque (output signal) d of the motor A and motor B sent from the motor A and B drive distribution calculation processing unit 35, and the torque of the motor A and motor B constituting each device. The command e is converted into a torque command for the clutch A and the clutch B, the torque command e (e ₁ , e ₂ ) is sent to the converted clutch A and the clutch B, or the clutch (open / close) command f is sent to the clutch A and the clutch B. (F ₁ , f ₂ ) are sent.

The required power calculation unit 33 detects the vehicle speed information a, the accelerator pedal operation amount b, and the brake pedal operation amount c, and calculates the required power Pt required for the electric vehicle 10. Specifically, the required power Pt of the vehicle is calculated by multiplying the required torque of the vehicle calculated with reference to the required torque map shown in FIG. 3 by the rotational speed of the wheel. The rotational speed of the wheel is a value calculated by dividing a preset conversion coefficient from the vehicle speed information a. This conversion coefficient is specifically the length of the outer periphery of the wheel. This required torque map is a curve that displays the relationship between the accelerator opening (accelerator pedal operation amount) and the vehicle speed and the relationship between the brake operation amount (brake pedal operation amount) and the vehicle speed for each accelerator opening and each brake operation. (A ₀ , A ₁ , A ₂ , B ₁ , B ₂ , B ₃ ). Required torque of the vehicle, when not depressed the accelerator 26, represented by curve _{A 0,} when stepping on the accelerator 26, for example, accelerator opening of 50%, power torque (curve _A 1 at 100% the accelerator opening, A ₂ ). When the brake 27 is depressed, the required torque is displayed with a stronger regenerative torque (curves B ₁ , B ₂ , B ₃ ). Curves B ₁ , B ₂ , and B ₃ are regenerative torque curves when the brake operation amount is 20%, 50%, and 100%.

Further, the motor A, B drive distribution calculation processing unit 35 calculates the drive distribution of the motor A and motor B when the energy loss of the motor A, motor B and transmission A (17), B (18) is minimized. Is calculated. The motor A and B drive distribution calculation processing unit 35 has a drive distribution ratio α _n of the motor A and the motor B in the range of 0 to 100% for the motor A and the range of 100 to 0% for the motor B (the motor A and the motor B). (The sum of the drive distributions is 100%) is sequentially selected and distributed. When the wheels are slipping, the motor driving amount on the slipping side is zero.

  FIG. 4 illustrates an example of calculation processing of the motor A and B drive distribution calculation processing unit 35 provided in the control unit 25 of the electric vehicle 10.

The required power setting unit 40 of the motor A / B drive distribution calculation processing unit 35 includes the required power Pt of the vehicle received from the required power calculation unit 33 and the motor A and motor from the motor A / B drive distribution range determination unit 34. The drive distribution ratio α _n selected from the B drive distribution range is input. The required power setting unit 40 calculates the required power candidate Pa for the motor A (or the required power candidate Pb = Pt−Pa for the motor B).

The motor A and B drive distribution range determination unit 34 sequentially transmits to the required power setting unit 40 a drive distribution ratio (distribution ratio) α _{n in} which the drive distribution range of the motor A and the motor B is changed in small increments by several percent. Yes. The drive distribution ratio α _n is provisionally determined and transmitted sequentially so that the sum of motor A and motor B is 100% in the range of 0 to 100% for motor A and 100 to 0% for motor B. .

Specifically, the drive distribution ratio α _n between the motor A and the motor B is _expressed as a percentage as an example in increments of 5%, (0, 100), (5, 95), ..., (n, 100-n), (N + 1, 100-n-1), ..., (95, 5), (100, 0) are sequentially changed and transmitted.

Then, in the required power setting unit 40 of the motor A, B drive distribution calculation processing unit 35, the required power Pt of the vehicle from the required power calculation unit 33 and the drive distribution ratio of the motor A and motor B from the motor drive distribution range determination unit 34. α _n is input, and the required power candidate Pa of motor A and the required power candidate Pb (= Pt−Pa) of motor B are calculated and set. The required power candidates Pa and Pb of the motor A and the motor B are calculated by the _n-th drive distribution ratio α _n for the motor A and the motor B, and are set in a tentatively determined form.

  Now, paying attention to the motor A, the required power candidate Pa set by the required power setting unit 40 is divided by the current motor rotation speed (of the motor A) (1/1 motor rotation speed is integrated by the integrator 41). The required motor torque candidate ta of the motor A is calculated. The calculated required motor torque candidate ta of the motor A is obtained by calculating an energy loss map 43 of the motor A in FIG. 5A described later from the current motor rotation speed (of the motor A) to the required motor torque candidate ta. The energy loss of the motor A (total energy loss of the motor and the inverter) lma when the motor A is operated with the required motor torque candidate ta is calculated, and this energy loss lma is sent to the adder 44.

  Similarly, the energy loss lta of the transmission A is calculated based on the power transmission path 17 (hereinafter referred to as transmission) of FIG. The energy loss lta of the transmission A is calculated using the energy loss map 45 of A.), and the value is input to the adder 44.

  Focusing on the motor B, the required power candidate Pb of the motor B can be expressed by the equation (Pt−Pa), and the required power candidate Pb of the motor B can be calculated in the same manner as the motor A. . The required power candidate Pb of the motor B is divided by the current motor rotation speed (of the motor B) (1 / the motor rotation speed is integrated by the integrator 46), and the required motor torque candidate tb of the motor B is calculated. The calculated required motor torque candidate tb of the motor B is obtained by calculating an energy loss map 47 of the motor B in FIG. 5B described later from the current motor rotation speed (of the motor B) to the required motor torque candidate tb. The energy loss of the motor B (total energy loss of the motor and the inverter) lmb when the motor B is operated with the required motor torque candidate tb is calculated, and the calculated value lmb is input to the adder 44.

  Similarly, the energy loss ltb of the transmission B is obtained by calculating the energy loss map 48 of the transmission B in FIG. 6B described later from the current motor rotation speed (of the motor B) to the required motor torque candidate tb of the motor B. The calculated value ltb is input to the adder 44.

Therefore, when the motor A and B drive distribution calculation processing unit 35 of the control unit 25 has a distribution ratio α _n with a drive distribution of the motor A and the motor B, the calculated energy loss lma of the motor A and the transmission A The energy loss lta, the energy loss lmb of the motor B, and the energy loss ltb of the transmission B are input to the adder 44 and added. In the adder 44, the values of the four individual energy losses are added to obtain the total energy loss Ltn [= Σ (lma + lta + lmb + lta)] of the motor A, transmission A and motor B, and transmission B.

  The total energy loss Ltn of the motor and transmission is stored in the energy loss storage unit 49. After the total energy loss Ltn is stored in the energy loss storage unit 49, it returns to the required power setting unit 40 again via the return circuit 50, and the motor A and B drive distribution calculation processing unit 35 is different from the previous calculation processing calculation example. The required power candidate Pa (of motor A) is set. Based on this other required power candidate Pa, the same calculation processing calculation is performed by the motor A and B drive distribution calculation processing unit 35 thereafter.

In the motor A and B drive distribution calculation processing unit 35, calculation processing calculation with different distribution ratios for the drive distribution ratios α _n of the motor A and the motor B is performed in a series of repeated calculations, for example, several tens of times. For example, the nth calculation processing calculation is performed when the motor A drive distribution is 30% and the motor B drive distribution is 70%, and the (n + 1) th calculation processing calculation is the motor A drive distribution, for example, 35%. This is performed when the motor B drive distribution is 65%. In a few percent increments, for example 5% increments, a series of 21 arithmetic processing calculations are performed. One calculation processing calculation takes less than 1 ms and requires processing time in MS units. Even in calculation processing calculations involving a series of repetitive calculations, each request obtained by several tens of energy loss calculation processing calculations in about 10 ms, for example. A required power value with the lowest energy loss is selected from the power values. The required powers Pa and Pb of the series of motors A and B are updated every 10 ms, for example.

  In this way, several tens of arithmetic processing calculations are repeatedly performed within the range where the drive distribution of the motor A is 0 to 100% and the drive distribution of the motor B is 100 to 0%. In the motor A and B drive distribution calculation processing unit 35, for example, the energy loss total Ltn of the motor and the transmission is obtained one after another by several tens of calculation processing calculations, and the obtained energy loss total Ltn is all energy loss storage unit. 49.

Among the total (motor and transmission) energy loss total ΣLtn stored in the energy loss storage unit 49, the motor having the smallest total energy loss Lt of the motor (motor A and motor B) and the transmission (transmission A and transmission B) The energy loss Lt _{min of the} transmission is output to each device command conversion unit 36 as an output signal d.

  Next, examples of energy loss maps 43 and 47 for motor A and motor B are shown in FIGS. 5 (A) and 5 (B), respectively.

FIG. 5A shows an example of the energy loss map 43 of the motor A that is the front wheel drive motor 15, for example. In the energy loss map 43 of the motor A, the horizontal axis represents the rotational speed (rpm) of the motor A, and the vertical axis represents the torque (N · m) of the motor A. The energy loss map 43 of the motor A represents an energy loss corresponding to the motor rotation speed and the motor torque (total energy loss of the motor A and the inverter 28) by a data map. In the energy loss map 43 of the motor A, curves connecting the points having the same energy loss are displayed as equal energy loss lines El _{a1 to} El _a9 .

  If the rotational speed of the motor A and the motor torque are known, the energy loss (kW) of the motor A can be obtained from the intersection of the rotational speed value and the torque value. For example, when the rotational speed of the motor A is 4000 rpm and the motor torque is 100 N · m, the energy loss of the motor A is represented by the symbol ELa, which is about 10 kW, for example.

FIG. 5B shows an example of the energy loss map 47 of the motor B which is the rear wheel driving motor 16. In the energy loss map 47 of the motor B, the horizontal axis indicates the rotation speed (rpm) of the motor B, and the vertical axis indicates the torque (N · m) of the motor B. The energy loss corresponding to speed and motor torque is represented by a data map. Also in the energy loss map 47 of the motor B, curves connecting points where the energy losses are equal are displayed by equal energy loss lines El _{b1 to} El _b5 .

  If the rotational speed of the motor B and the motor torque are known, the energy loss (kW) of the motor B can be known from the intersection of each value. For example, when the rotational speed of the motor B is 4000 rpm and the motor torque is 100 N · m, the energy loss of the motor A is represented by the symbol ELb, which is about 13 kW, for example.

  As can be seen from the examples of the energy loss maps 43 and 47 of the motor A and the motor B, the motor A and the motor B are examples using different motors having different energy loss characteristics, in other words, two motors having different motor output characteristics.

For example, it can be seen from the arrangement relationship of the equal energy loss lines El _{a1 to} El _a9 that the motor A is a motor that is more energy efficient in the high speed region than the equal energy loss lines El _{b1 to} El _b9 of the motor B. . The motor B is a motor that is more efficient in the low speed range than the motor A.

  In an electric vehicle in which the motor characteristics of the motor A and the motor B are different, the power running or regeneration can be efficiently performed by selecting the front and rear motor A and motor B torque combinations that have the smallest total energy loss at a certain motor rotation speed. Can do. For this reason, the electric energy of the battery 29 can be converted into drive energy with energy efficiency, and the deceleration energy can be regenerated with energy efficiency.

  Further, the energy loss maps 43 and 47 of the motor A and the motor B represent the total energy loss of the motors 17 and 18 and the inverter 28 in a data map, and the total energy loss of the motor and the inverter is represented by a known test bench (not shown). The measurement data is obtained by measuring in advance with the above. The energy loss maps 43 and 47 of the motor A and the motor B shown in FIGS. 5A and 5B are examples of the motor rotation speed and the motor torque as input, but the energy loss also varies depending on the motor temperature. If there is an energy loss characteristic for each motor temperature, more accurate energy loss calculation can be obtained, and more accurate energy loss maps of motor A and motor B can be obtained.

  Next, examples of energy loss maps 45 and 48 for transmission A and transmission B are shown in FIGS. 6A and 6B, respectively.

FIG. 6A shows an energy loss map 45 of the transmission A (17) operated by the motor A of the front wheel drive motor 15. The energy loss map 45 of the transmission A shows the input rotation speed (rpm) of the transmission A on the horizontal axis and the input torque (N · m) on the vertical axis, and the energy loss corresponding to the input rotation speed and the input torque is a data map. Is displayed. In the energy loss map 45 of the transmission A, a curve connecting points where energy losses are equal is displayed as Et _a1 to Et _a7 as equal energy loss lines.

  If the (input) rotational speed of transmission A and its torque are known, the energy loss (kW) of transmission A can be determined from the intersection of the rotational speed value and the torque value. For example, when the input rotation speed of the transmission A is 4000 rpm and the input torque is 100 N · m, the energy loss position is represented by the symbol ETa.

  FIG. 6B shows an energy loss map 48 of the transmission B (18) operated by the motor B which is the rear wheel driving motor 16. Also in the energy loss map 48 of the transmission B, the horizontal axis indicates the input rotation speed (rpm) of the transmission B, and the vertical axis indicates the input torque (N · m) of the transmission B. The energy loss corresponding to the input rotation speed and the input torque is displayed in a data map. For example, when the input rotation speed is 4000 rpm and the input torque is 100 N · m, the energy loss position is represented by the symbol ETb.

  As for the energy loss characteristics of the transmission A and the transmission B, measurement data is acquired by measuring the input rotational torque and the energy loss for each temperature using a known test bench (not shown). Similar to the energy loss maps 43 and 47 of the motor A and the motor B, energy loss maps 45 and 48 of the transmission A and the transmission B are created from the measurement data.

  Next, an example of vehicle control in the control unit provided in the electric vehicle will be described with reference to FIG.

  The electric vehicle 10 is a four-wheel drive EV vehicle that drives the left and right front wheels 11 and the rear wheels 12 with two motors A and B, as shown in FIG. As motors A and B, motors having different motor characteristics are used. In one example, the motor A is a motor that is efficient in the high speed range, and the motor B is a motor that is efficient in the low speed range. Various other combinations of use of motor A and motor B are also conceivable.

  In the control unit 25 provided in the electric vehicle 10, various controls are performed as the electric vehicle 10 is operated. The control unit 25 is started as the electric vehicle 10 is driven, and vehicle information such as driver operation information and vehicle speed is taken into the control unit 25 (step S1).

  An accelerator pedal operation amount b, a brake pedal operation amount c, and vehicle speed information a, which are vehicle information, are taken into the control unit 25, and the control unit 25 calculates the energy loss of the motor A and the motor B. (Step S2).

  In the electric vehicle 10, the drive distribution ratio (distribution ratio) α of the motor A and the motor B is adjusted and controlled by the control unit 25 so that the energy loss of the motor and the transmission is minimized according to the driving conditions of the vehicle. Thus, each motor output control of motor A and motor B is performed (step S3). A method for calculating the motor and the transmission will be described later.

  When the combination of the motor A and the motor B is selected by the output control of each motor and the power required or the regeneration is controlled so that the energy loss is minimized and the optimum required power Pt is used, the electric energy of the battery 29 is efficiently used. It can be well converted into drive energy, and deceleration energy can be efficiently regenerated.

  Since the electric vehicle 10 is an EV vehicle that keeps the energy loss of the motor and the transmission to a minimum and is driven by four motors by the two motors A and B, each device can be operated while stabilizing the behavior of the vehicle. The command converter 36 can perform output control of the motor A and motor B (step S3), and can perform clutch (open / close) control of the clutch A (22) and clutch B (23) (step S4).

  In the motor output control in step S3, the motor output (torque) control of the front and rear motors A and B is performed in the lowest energy loss state with the least energy loss, so that the power consumption (km / kWh) can be improved or One charging mileage in charging can be extended.

  The clutch opening / closing control (step S4) is performed as follows. Focusing on the clutch A (22), when the required motor torque command is 0, the motor A torque is not required. At this time, if the clutch A (22) is engaged, a hydraulic pressure loss of the clutch A, a bearing of the motor A, and a magnetic force loss occur, so the clutch A is released. In other cases, the clutch A is fastened.

  When the clutch A is engaged while the electric vehicle 10 is traveling, the motor A torque is generated in advance to control the rotation, and the clutch A is turned on with the rotation between the motor A and the transmission A input side substantially synchronized. And fasten.

  For motor B, the same processing as in motor A is performed and clutch (open / close) control is performed.

  As described above, the transmission A (17) and the transmission B (18) have the clutch A (22) and the clutch B (23) for fastening and releasing the gears of the motor A and the motor B, respectively. While the electric vehicle 10 is traveling, when the required power Pt to the motor A or B is 0, the clutch on the side where the required power Pt is 0 is released.

  In clutches A (22) and B (23) of transmissions 17 and 18, clutch hydraulic pressure loss and loss due to motor bearings and magnetic force are generated during clutch engagement, but energy loss due to these losses occurs due to clutch release. Therefore, it is possible to improve the electricity consumption (km / kWh) and extend the one-charge travel distance by full charge.

  Next, the energy loss calculation method for motor A and motor B described above will be described.

  Calculation of energy loss of the motor A and the motor B is performed in the control unit 25 of the electric vehicle 10. First, the controller 25 calculates the required power Pt of the vehicle using the required power map of the vehicle shown in FIG. Input to the unit 35.

On the other hand, the motor A and B drive distribution range determination unit 34 of the control unit 25 shown in FIG. 4 has a drive distribution ratio (distribution ratio) α _n (α ₁ , α ₂ ,..., Α _n ) between the motor A and the motor B. Are sequentially determined in the provisional determination state. As the drive distribution ratio of the motor A and the motor B, the distribution ratio α _n at a certain point in time, for example, the distribution ratio when the motor A is 10% and the motor B is 90% is selected and temporarily determined to drive the motors A and B. This is input to the distribution calculation processing unit 35.

Next, it is sent to the motors A and B drive distribution calculation processing unit 35, and the required power setting unit 40 integrates the required power Pt of the vehicle and the drive distribution ratio α _n to obtain the motor A at a certain drive distribution ratio α _n . Required power candidate Pa and motor B required power candidate Pb (= Pt−Pa).

  Further, since the motor power is represented by motor power = motor rotational speed × motor torque, the accumulators 41 and 46 use the current motor A rotational speed and the current motor B rotational speed to calculate the motor A torque candidate ta and the motor. A B torque candidate tb is calculated.

  Subsequently, using the current motor rotation speeds for the motor A and the motor B and the calculated motor request power candidates ta and tb, the motor energy loss maps 43 and 47 and the transmission energy loss maps 45 and 48 are used. , B energy losses lma, lmb and transmissions A, B energy losses lta, ltb, respectively.

  Specifically, the motor A energy loss candidate lma, the transmission A energy loss candidate lta, the motor A energy loss map 43, and the transmission A energy loss map 45 are obtained from the motor A torque candidate ta and the current motor A rotation speed. Calculate using each.

  Further, from the motor B torque candidate tb and the current motor B rotation speed, the motor B energy loss candidate lmb and the transmission B energy loss candidate ltb are used, and the motor B energy loss map 47 and the transmission B energy loss map 48 are used. calculate.

Next, the adder 44 adds the motor A energy loss candidate lma, the transmission A energy loss candidate lta, the motor B energy loss candidate lmb, and the transmission B energy loss candidate ltb by the adder 44, and the addition value Σ (Lma + lta + lmb + ltb) is stored in the energy loss storage unit 49 as the energy loss Ltn at the drive distribution ratio α _n .

Next, instead of the drive distribution ratio (distribution ratio) α _n between the motor A and the motor B, the following distribution ratio α _{n + 1} , for example, the distribution ratio of 20% for the motor A and 80% for the motor B is used. It performs similar processing computation to obtain a sum of at distribution ratio alpha _{n + 1,} are stored in the energy loss Lt _{(n + 1)} energy loss storage unit 49 as in the drive distribution ratio alpha _{n + 1.}

Thereafter, calculation processing calculation in which the drive distribution ratio α _n of the motor A and the motor B is sequentially changed is repeated in the motor A and B drive distribution calculation processing unit 35. The number of repetitions of the arithmetic processing calculation is performed, for example, when the drive distribution ratio (distribution ratio) α _n of the motor A and the motor B is 11 times in 10% increments and 21 times in 5% increments.

After iteration of the series of processing is ended, among the energy loss Lt ₁ to LT _n of each distribution ratio alpha ₁ to? _N, the least energy loss, motor A and motor energy loss EL driving distribution ratio alpha of B _min is selected. In the energy loss storage unit 49, the energy loss Lt _min of the drive distribution ratio (distribution ratio) α between the motor A and the motor B having the smallest energy loss among the energy losses EL _{1 to} EL _n obtained by a series of arithmetic processing calculations. Becomes an output signal d (optimum required power PA of motor A, required power PB of motor B) and is output to each device command conversion unit 36.

  In the electric vehicle 10 of the present embodiment, the energy loss between the motor A and the motor B that drive the front wheels 11 and the rear wheels 12 by the control unit 25 and the transmission A and the transmission B that constitute the power transmission path is minimized. The motor output control operation is performed.

  In the motor output control operation of the electric vehicle 10, the control unit 25 performs motor output control and clutch opening / closing control.

In the motor output control method of the electric vehicle 10, the step of calculating the required power Pt of the vehicle by the required power calculation unit 33 from the vehicle operation information and the vehicle information and the required power map of the vehicle, the front wheel drive motor 15 and the rear Within the drive distribution range with the wheel drive motor 16, the step of sequentially determining the drive distribution ratio α _n of the motors 15 and 16 by the motor A and B drive distribution range determination unit 34, and the required power Pt of the vehicle The motor drive distribution calculation processing unit 35 to which the required drive distribution ratio α _n is inputted performs calculation processing calculation using the motor energy loss maps 43 and 47 and the transmission energy loss maps 45 and 48 to obtain the required drive distribution ratio α. after storage to calculate the energy loss total Ltn motor and transmission in _n, motor for rear wheel drive and front-wheel drive motor 15 The drive distribution ratio alpha _n of the motors in the drive allocation range of the motor 16 by sequentially changing by a predetermined distribution ratio, repeatedly performing a series of processing calculated by the motor drive allocation processing section 35, the drive distribution ratio And calculating and storing the total energy loss ΣLtn of the motor and the transmission at each of the plurality of stored energy losses ΣLtn of the plurality of motors and transmissions by repeating a series of arithmetic processing calculations. An output signal d is output to each device command conversion unit 36 based on the total loss Lt _min . The device command conversion unit 36 converts the output signal d into required powers e (e ₁ , e ₂ ) and f (f ₁ , f ₂ ) of each device (motor A, motor B and clutch A, clutch B). Based on the required power e (e ₁ , e ₂ ) and f (f ₁ , f ₂ ), the motor control of the motor A and the motor B and the clutch open / close control of the clutch A and the clutch B are performed. Is doing. In this way, the control unit 25 performs motor output (torque) control of the motor A and motor B, performs clutch opening / closing control of the clutch A and clutch B, and performs motor output (torque) control of the electric vehicle 10. Is done.

[Effect of the embodiment]
In the electric vehicle 10 of the present embodiment, motor output control and clutch (open / close) control are performed by the control unit 25, and motor drive control of the motor A and motor B is performed in the electric vehicle 10. The electric vehicle 10 uses the motor A and the motor B having different energy (motor) characteristics to control the output torque of the motor A and the motor A and the clutch A and the clutch B so that the energy loss of the motor and the transmission is minimized. Clutch control is performed. In this electric vehicle 10, the energy efficiency of driving and regeneration can be improved.

  Of the motor A and the motor B provided in the electric vehicle 10, in order to disengage the clutch A or the clutch B on the side of the motor A or the motor B that does not output torque, the mechanical energy loss in the transmission or the motor may be eliminated. It is possible to improve the energy efficiency of driving and regeneration.

In the electric vehicle 10, the motor output torque is controlled using the motor A and the motor B having different energy characteristics so that the total energy loss EL _min of the motor A and the motor B is minimized. For this reason, compared with the case where it comprises two motors having the same energy characteristics, in this embodiment, the total energy loss at the motor rotation speed executed by the motor A and the motor B can be further reduced. The energy efficiency of driving and regeneration can be increased.

  Furthermore, the electric vehicle 10 according to the present embodiment calculates the total energy loss with reference to the energy loss maps of the motor A and the motor B having different energy characteristics and the power transmission path of the transmission, and the total energy loss is the lowest. Since the motor torque control and the clutch opening / closing control are performed as described above, the energy efficiency of driving and regeneration can be further improved.

  In addition, in the electric vehicle 10 according to the present embodiment, the EV vehicle that maintains the function of four-wheel drive with the two motors A and B allows the motor A and the motor B with the least energy loss while stabilizing the drive of the vehicle. By using it, it is possible to improve the electricity cost (km / kWh) and to extend the one-charge travel distance (by full charge).

[Other Embodiments]
In the electric vehicle 10 according to the present embodiment, an example in which two motors having different energy characteristics (motor characteristics) of the motor A and the motor B is used has been described. This can be applied to electric vehicles having different gear ratios. Further, the present invention can be applied to the case where the motor characteristics of the two motors are the same and the gear ratios of the front and rear transmissions are exactly the same.

  Moreover, in the electric vehicle 10 of the present embodiment, an example of a four-wheel drive vehicle using one motor A on the front wheel side and one motor B on the rear wheel side is shown, but the left and right front wheels and rear wheels are shown. It is good also as an electric vehicle which attaches the motor which drives each independently, and uses four motors.

  Furthermore, although the electric vehicle 10 of the present embodiment has been described as an example of an EV four-wheel drive vehicle, as shown in FIG. 1, a power generation unit 55 including a power generation engine, a generator, and an inverter is mounted. The power generation unit 55 can be applied to a series-type hybrid vehicle in which the battery 29 is charged.

  The embodiment of the present invention has been presented as an example, and is not intended to limit the scope of the invention. These embodiments can be implemented in various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Electric vehicle, 11 ... Front wheel, 12 ... Rear wheel, 13, 14 ... Drive shaft, 15 ... Front-wheel drive motor (motor A), 16 ... Rear-wheel drive motor (motor B), 17 ... Power transmission path ( Transmission A), 18 ... Power transmission path (Transmission B), 20, 21 ... Reducer, 22 ... Clutch mechanism (Clutch A), 23 ... Clutch mechanism (Clutch B), 25 ... Control part (ECM), 26 ... Accelerator 27 ... Brake, 28 ... Inverter, 29 ... Battery, 33 ... Required power calculation unit, 34 ... Motor A, B drive distribution range determination unit, 35 ... Motor A, B drive distribution calculation processing unit, 36 ... Each device command conversion 40, required power setting unit, 41, 46 ... integrator, 43 ... energy loss map of motor A, 44 ... adder, 45 ... energy loss map of transmission A 47 ... motor energy loss map of B, 48 ... transmission energy loss map of B, 49 ... energy loss storage unit, 50 ... return circuit, 55 ... power unit.

Claims (5)

A first wheel motor capable of transmitting a driving force to the first wheel;
A second wheel motor capable of transmitting driving force to the second wheel;
An electric vehicle comprising: a control unit that controls output torques of the first wheel motor and the second wheel motor;
A first wheel clutch for connecting and disconnecting power transmission between the first wheel and the first wheel motor; and a second wheel clutch for connecting and disconnecting power transmission between the second wheel and the second wheel motor. And
The control unit includes an energy loss in the first wheel motor, an energy loss in a power transmission path between the first wheel motor and the first wheel, and an energy loss in the second wheel motor. The first wheel motor and the second wheel so that the total energy loss, which is the sum of the energy losses in the power transmission path between the second wheel motor and the second wheel, is minimized. An electric vehicle configured to perform torque control of a motor and clutch control of the first wheel clutch and the second wheel clutch. The control unit disconnects power transmission of the first wheel clutch when the first wheel motor does not output torque,
2. The electric vehicle according to claim 1, wherein when the second wheel motor does not output torque, the power transmission of the second wheel clutch is cut off. 3. The electric vehicle according to claim 1, wherein the first wheel motor and the second wheel motor have different energy loss characteristics. The control unit calculates the energy loss of the first wheel motor based on the rotation speed and output torque of the first wheel motor, and the first wheel motor energy and loss map;
A first wheel power transmission path energy loss for calculating an energy loss in a power transmission path between the first wheel motor and the first wheel based on a rotation speed and an output torque of the first wheel motor. Map and
A second wheel motor energy loss map for calculating an energy loss of the second wheel motor based on a rotation speed and an output torque of the second wheel motor;
Second wheel power transmission path energy loss map for calculating energy loss in the power transmission path between the second wheel motor and the second wheel based on the rotational speed and output torque of the second wheel motor. And having
The electric vehicle according to claim 3, wherein the total energy loss is calculated with reference to each energy loss map. Calculating the required power of the vehicle from vehicle operation information and vehicle information, the required torque map of the vehicle, and the rotational speed of the wheels;
Sequentially determining the drive distribution ratio of both motors within the drive distribution range of the first wheel motor and the second wheel motor;
A motor drive distribution calculation processing unit that inputs the required power of the vehicle and a required drive distribution ratio performs calculation processing using a motor energy loss map and a transmission energy loss map, and the motor at the required drive distribution ratio After calculating and storing the total transmission energy loss,
Within the drive distribution range of the first wheel motor and the second wheel motor, the drive distribution ratios of both motors are sequentially changed by a predetermined distribution ratio, and the motor drive distribution calculation processing unit performs a series of the calculation processes. Carrying out calculation repeatedly and calculating and storing the total energy loss of the motor and transmission at each drive distribution ratio,
An electric vehicle that performs motor output and clutch connection / disconnection control based on the smallest total energy loss among a plurality of stored energy losses of a plurality of motors and transmissions by repeating the series of arithmetic processing calculations. Motor output control method.

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