Electric vehicle

Abstract

To suppress input / output with excessive power of a power storage device and a boost converter.SOLUTION: First motors and a second motor are controlled so that the sum of first power of a plurality of first motors and second power of the second motor is within the range of a first input limit and a first output limit of a power storage device, and the first power is within the range of a second input limit and a second output limit of a boost converter. In this case, the upper limit power of the second motor is set on the basis of the second input limit and required charging power of the power storage device, the lower limit power of the second motor is set on the basis of the first input limit and the second output limit, and the second motor is controlled so that the second power is within the ranges of the upper limit power and the lower limit power.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to electric vehicles. [Background technology]

[0002] A conventional electric vehicle of this type has been proposed in which a generator motor, an engine, and a drive motor are connected to the sun gear, carrier, and ring gear of a planetary gear, respectively, and a battery is connected to a power line that can exchange power with the generator motor and the drive motor (see, for example, Patent Document 1).In this electric vehicle, upper and lower torque limits for the generator motor are set based on the input / output limits of the battery, the power required by the drive motor, and the power required by the auxiliary equipment, and the target engine speed is set so that the torque of the generator motor falls within the range of the upper and lower torque limits. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-39880 A Summary of the Invention [Problem to be solved by the invention]

[0004] One possible configuration for an electric vehicle is one that includes at least one first motor, a second motor, a power storage device, and a boost converter that is connected to a high-voltage power line capable of exchanging power with the at least one first motor and a low-voltage power line capable of exchanging power with the second motor and the power storage device and that can boost the power of the low-voltage power line and supply it to the high-voltage power line or reduce the power of the high-voltage power line and supply it to the low-voltage power line. In this configuration, there is a need to devise a method for suppressing excessive input or excessive output of the power storage device and the boost converter.

[0005] The electric vehicle of the present disclosure has a primary objective of suppressing excessive input / output of electric power to / from the power storage device and the boost converter. [Means for solving the problem]

[0006] The electric vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] An electric vehicle disclosed herein includes at least one first motor, a second motor, a power storage device, a boost converter connected to a high-voltage power line capable of exchanging power with the at least one first motor and a low-voltage power line capable of exchanging power with the second motor and the power storage device, and a control device that controls the at least one first motor and the second motor so that a sum of a first power of the at least one first motor and a second power of the second motor is within a first input limit and a first output limit of the power storage device and the first power is within a second input limit and a second output limit of the boost converter, wherein the control device sets an upper limit power of the second motor based on the second input limit and a required charging power of the power storage device, and sets a lower limit power of the second motor based on the first input limit and the second output limit, and controls the second motor so that the second power is within the range between the upper limit power and the lower limit power.

[0008] In the electric vehicle disclosed herein, the first motor and the second motor are controlled so that the sum of the first power of at least one first motor and the second power of the second motor is within the range of the first input limit and the first output limit of the power storage device, and the first power is within the range of the second input limit and the second output limit of the boost converter. In this case, the upper limit power of the second motor is set based on the second input limit and the required charging power of the power storage device, and the lower limit power of the second motor is set based on the first input limit and the second output limit, and the second motor is controlled so that the second power is within the range of the upper limit power and the lower limit power. This makes it possible to suppress excessive input and output of power to the power storage device and the boost converter. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a hybrid vehicle 20 according to the present disclosure. [Diagram 2] 11 is a flowchart showing an example of a processing routine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a hybrid vehicle 20 of the present disclosure. As shown in the figure, the hybrid vehicle 20 includes an engine 22, a planetary gear 30, motors MG1 and MG2 (at least one first motor), a motor MGR (second motor), inverters 41, 42, and 43, a battery (electricity storage device) 50, a boost converter 55, an auxiliary device 60, and an electronic control unit (hereinafter referred to as "ECU") 70.

[0011] The engine 22 is configured as an internal combustion engine that outputs power using gasoline, diesel, or the like as fuel. The planetary gear 30 is configured as a single pinion type planetary gear mechanism. A sun gear of the planetary gear 30 is connected to a rotor of the motor MG1, a ring gear is connected to a front wheel drive shaft linked to the front wheels, and a carrier is connected to the crankshaft of the engine 22.

[0012] The motors MG1, MG2, and MGR are all configured as synchronous generator motors. The rotor of the motor MG2 is connected to a front-wheel drive shaft, and the rotor of the motor MGR is connected to a rear-wheel drive shaft linked to the rear wheels. The inverters 41, 42, and 43 each drive and rotate the motors MG1, MG2, and MGR by switching a plurality of switching elements. The inverters 41 and 42 are connected to a high-voltage power line 54a, and the inverter 43 is connected to a low-voltage power line 54b. A smoothing capacitor 57 is attached to the high-voltage power line 54a, and a smoothing capacitor 58 is attached to the low-voltage power line 54b.

[0013] Battery 50 is, for example, a lithium ion secondary battery or a nickel metal hydride secondary battery, and is connected to low-voltage power line 54b. Boost converter 55 is connected to high-voltage power line 54a and low-voltage power line 54b, and by switching a plurality of switching elements, boosts the power of low-voltage power line 54b and supplies it to high-voltage power line 54a, or reduces the power of high-voltage power line 54a and supplies it to high-voltage power line 54a. An example of auxiliary device 60 is an air conditioner that conditions the air in the vehicle cabin.

[0014] The ECU 70 includes a microcomputer, which has a CPU, a ROM, a RAM, a flash memory, and an input / output port. Signals are input to the ECU 70 from various sensors. Examples of the signals input to the ECU 70 include signals related to the state of the engine 22, such as the crank angle θcr of the crankshaft of the engine 22 from the crank angle sensor 22a. Examples of the signals input to the ECU 70 include signals related to the state of the motors MG1, MG2, and MGR, such as the rotational positions θm1, θm2, and θm3 of the rotors of the motors MG1, MG2, and MGR from the rotational position sensors 45, 46, and 47. Examples of the signals related to the state of the battery 50, such as the voltage Vb, current Ib, and temperature Tb of the battery 50 from the voltage sensor 50a, current sensor 50b, and temperature sensor 50c. Examples of the signals include the voltages VH and VL of the capacitors 57 and 58 (high-voltage side power lines 54a and 54b) from the voltage sensors 57a and 58a. Examples of the signals include the power Ph of the auxiliary device 60. Other examples include the ignition signal from the ignition switch, the operating position of the shift lever from the shift position sensor (shift position SP), the amount of accelerator pedal depression from the accelerator sensor (accelerator opening Acc), the amount of brake pedal depression from the brake sensor (brake pedal position BP), and the vehicle speed V from the vehicle speed sensor.

[0015] Various control signals are output from the ECU 70. Examples of the signals output from the ECU 70 include a control signal to the engine 22, a control signal to the inverters 41, 42, and 43, a control signal to the boost converter 55, and a control signal to the auxiliary device 60. The ECU 70 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the crankshaft of the engine 22, and calculates the rotation speeds Nm1, Nm2, and Nm3 of the motors MG1, MG2, and MGR based on the rotation positions θm1, θm2, and θm3 of the rotors of the motors MG1, MG2, and MGR. The ECU 70 calculates the charge storage percentage SOC of the battery 50 based on the integrated value of the current Ib of the battery 50.

[0016] The hybrid vehicle 20 of this embodiment configured in this manner runs by switching between multiple driving modes, including a hybrid driving (HV driving) mode in which the vehicle runs with the engine 22 operating, and an electric driving (EV driving) mode in which the vehicle runs without the engine 22 operating.

[0017] In the HV driving mode, the ECU 70 first sets a torque requirement Td* for driving based on the accelerator opening Acc and the vehicle speed V, and then sets a power requirement Pd* for driving based on the set torque requirement Td* and the vehicle speed V. Next, the ECU 70 calculates a power requirement Pe* for the engine 22 by subtracting a charge / discharge power requirement Pb* (where the side discharging from the battery 50 is a positive value) based on the charge storage rate SOC of the battery 50 from the power requirement Pd*. Then, the ECU 70 sets a target speed Ne* and a target torque Te* for the engine 22, and torque commands Tm1*, Tm2*, and Tmr* for the motors MG1, MG2, and MGR so that the power requirement Pe* is output from the engine 22 and the torque requirement Td* is distributed based on a distribution ratio kt within the ranges of the input / output limits Winb and Woutb of the battery 50 and the input / output limits Winc and Woutc of the boost converter 55 to be output to the front and rear wheels. The distribution ratio kt is the ratio of the torque output to the front wheels to the sum of the torque output to the front wheels and the torque output to the rear wheels, and is set based on the running state of the vehicle. Furthermore, the operation of engine 22 is controlled so that engine 22 is operated based on target rotation speed Ne* and target torque Te*, and inverters 41, 42, 43 are controlled so that motors MG1, MG2, MGR are driven by torque commands Tm1*, Tm2*, Tmr*. Furthermore, a target voltage VH* of high-voltage side power line 54a is set so that motors MG1, MG2 can be driven at target driving points (torque commands Tm1*, Tm2* and rotation speeds Nm1, Nm2), and boost converter 55 is controlled so that voltage VH of high-voltage side power line 54a becomes target voltage VH*.

[0018] In the EV driving mode, the ECU 70 first sets the required torque Td* and the required power Pd* in the same manner as in the HV driving mode. Then, the torque command Tm1* of the motor MG1 is set to a value of 0, and the torque commands Tm2* and Tmr* of the motors MG2 and MGR are set so that the required torque Td* is distributed based on the distribution ratio kt within the range of the input / output limits Winb and Woutb of the battery 50 and the input / output limits Winc and Woutc of the boost converter 55 and output to the front and rear wheels. The control of the inverters 41, 42, and 43 based on the torque commands Tm1*, Tm2*, and Tmr* and the control of the boost converter 55 are similar to those in the HV driving mode.

[0019] Next, the operation of the hybrid vehicle 20 of this embodiment, particularly the process of setting the torque commands Tm1*, Tm2*, and Tmr* of the motors MG1, MG2, and MGR will be described. FIG. 2 is a flowchart showing an example of a process routine executed by the ECU 70. This routine is executed repeatedly. In the following description, the discharge side of the power of the battery 50 is a positive value and the charge side is a negative value, the drive side of the power of the motors MG1, MG2, and MGR is a positive value and the power generation side is a negative value, and the power of the boost converter 55 is a positive value in the direction from the low-voltage side power line 54b to the high-voltage side power line 54a, and a negative value in the opposite direction.

[0020] 2, the ECU 70 sets the upper limit power Prmax of the motor MGR according to equation (1) using the input limit Winc of the boost converter 55, the power Ph of the auxiliary device 60, and the charge / discharge power requirement Pb* of the battery 50 (step S100). Then, the ECU 70 sets the lower limit power Prmin of the motor MGR according to equation (2) using the input limit Winb of the battery 50, the output limit Woutc of the boost converter 55, and the power Ph of the auxiliary device 60 (step S110). Note that when setting the upper limit power Prmax and the lower limit power Prmin, losses may be taken into consideration.

[0021] Prmax=-Winc-Ph-max(-Pb*,0) (1) Prmin=Winb-Woutc-Ph (2)

[0022] Then, the motor MGR's upper and lower limit powers Prmax and Prmin are used to execute torque limiting processing for the motor MGR (step S120). In this processing, the motor MGR's torque command Tmr* is set so that the power Pmr of the motor MGR, obtained as the product of the torque command Tmr* and the rotation speed Nmr of the motor MGR, falls within the range of the upper and lower limit powers Prmax and Prmin. For example, the torque command Tmr* is set by limiting the temporary value Tmrtmp of the torque command Tmr* based on the required torque Td* and the distribution ratio kt so that the power Pr falls within the range of the upper and lower limit powers Prmax and Prmin.

[0023] In addition, torque limiting processing of the motors MG1 and MG2 is executed (step S130) using the conditions of formulas (3) and (4) regarding the relationship between the powers Pm1, Pm2, and Pmr of the motors MG1, MG2, and MGR, which are obtained as the product of the torque commands Tm1*, Tm2*, and Tmr* of the motors MG1, MG2, and MGR and the rotation speeds Nm1, Nm2, and Nmr of the motors MG1, MG2, and MGR, the input / output limits Winb and Woutb of the battery 50, and the input / output limits Winc and Woutc of the boost converter 55. The formula (3) is the condition under which the powers Pm1, Pm2, and Pmr of the motors MG1, MG2, and MGR are within the range of the input / output limits Win and Wout of the battery 50. The formula (4) is the condition under which the sum of the powers Pm1 and Pm2 of the motors MG1 and MG2 is within the range of the input / output limits Win and Wout of the boost converter 55. In the process of step S130, the torque commands Tm1*, Tm2* of the motors MG1, MG2 are set so as to satisfy the conditions of equations (3) and (4). For example, the temporary values ​​Tm1tmp, Tm2tmp of the torque commands Tm1*, Tm2* based on the required torque Td*, the distribution ratio kt, and the target speed Ne* and target torque Te* of the engine 22 are limited so as to satisfy the conditions of equations (3) and (4) to set the torque commands Tm1*, Tm2*.

[0024] Winb≦Pm1+Pm2+Pmr≦Woutb (3) Winc≦Pm1+Pm2≦Woutc (4)

[0025] By setting the torque commands Tm1*, Tm2*, Tmr* of the motors MG1, MG2, MGR in this manner, it is possible to suppress excessive input / output of power to the battery 50 and the boost converter 55.

[0026] In the hybrid vehicle 20 of the present embodiment described above, the torque commands Tm1*, Tm2*, Tmr* of the motors MG1, MG2, MGR are set to control the motors MG1, MG2, MGR so that the powers Pm1, Pm2, Pmr of the motors MG1, MG2, MGR are within the ranges of the input / output limits Win, Wout of the battery 50, and the sum of the powers Pm1, Pm2 of the motors MG1, MG2 is within the ranges of the input / output limits Win, Wout of the boost converter 55. In this case, the upper limit power Pmrmax of the motor MGR is set based on the input limit Winc of the boost converter 55 and the charge / discharge required power Pb* of the battery 50, and the lower limit power Prmin of the motor MGR is set based on the input limit Winb of the battery 50 and the output limit Woutc of the boost converter 55, and the torque command Tmr* of the motor MGR is set so that the power Pmr of the motor MGR is within the ranges of the upper and lower limit powers Pmrmax, Pmrmin. This makes it possible to suppress excessive input and output of power to and from the battery 50 and the boost converter 55.

[0027] In the above-described embodiment, the battery 50 is used as the power storage device, but a capacitor may also be used.

[0028] In the above-described embodiment, a description has been given of the configuration of the hybrid vehicle 20 including the engine 22, the motors MG1, MG2, MGR, the battery 50, and the boost converter 55. However, the hybrid vehicle 20 may have a configuration of an electric vehicle in which the engine 22 and the motor MG1 are removed.

[0029] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on Means for Solving the Problems will be described below. In the embodiment, the motors MG1 and MG2 correspond to "at least one first motor", the motor MGR corresponds to "second motor", the battery 50 corresponds to "electricity storage device", the boost converter 55 corresponds to "boost converter", and the ECU 70 corresponds to "control device".

[0030] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure. [Industrial Applicability]

[0031] The present disclosure can be used in the electric vehicle manufacturing industry and the like. [Explanation of symbols]

[0032] 20 hybrid vehicles, 50 batteries, 55 boost converters, 70 ECUs, MG1, MG2, MGR motors.

Claims

[Claim 1] an electric vehicle including at least one first motor, a second motor, a power storage device, a boost converter connected to a high-voltage power line capable of exchanging power with the at least one first motor and a low-voltage power line capable of exchanging power with the second motor and the power storage device, and a control device that controls the at least one first motor and the second motor such that a sum of a first power of the at least one first motor and a second power of the second motor is within a first input limit and a first output limit of the power storage device and the first power is within a second input limit and a second output limit of the boost converter, the control device sets an upper limit power of the second motor based on the second input limit and a required charging power of the power storage device, and sets a lower limit power of the second motor based on the first input limit and the second output limit, and controls the second motor so that the second power is within a range between the upper limit power and the lower limit power. Electric car.

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