JP2023117689A - vehicle - Google Patents

Abstract

To provide a vehicle that is configured to be able to prevent a plurality of electric motor from being brought into a high-temperature state, while preventing the configuration of the vehicle from being complicated.SOLUTION: A control device 20 derives estimated rotation speeds that are estimated values of rotation speeds of motor generators and estimated torque that is an estimated value of output torque, at the time when a vehicle 10 travels on a travelling scheduled route; derives an estimated boosted voltage that is an estimated value of a boosted voltage of a voltage control device 110 at the time when the vehicle travels on the travelling scheduled route, on the basis of the derived estimated rotation speed and the derived estimated torque; estimates temperatures of the motor generators at the time when the derived estimated boosted voltages are supplied to the motor generators; when a temperature of any motor generator of the estimated temperatures of the motor generators exceeds a threshold, derives a corrected boosted voltage determined by correcting the estimated boosted voltage so as to prevent the temperature of the motor generator from rising; and controls the boosted voltage of the voltage control device 110 at the time when the vehicle travels on the travelling scheduled route, on the basis of the derived corrected boosted voltage.SELECTED DRAWING: Figure 1

Description

The present invention relates to vehicles.

In recent years, as a concrete countermeasure against global climate change, efforts toward realization of a low-carbon society or a decarbonized society have been activated. Vehicles such as automobiles are also required to reduce CO ₂ emissions and improve energy efficiency, and electrification of drive sources is progressing. Specifically, a vehicle (hereinafter also referred to as an "electric vehicle", such as an electric vehicle) is developed that includes an electric motor as a drive source for driving the drive wheels and a battery as a secondary battery capable of supplying power to the electric motor. It is

Generally, in an electric vehicle, a power conversion device is provided between the battery and the electric motor for converting electric power transferred between the battery and the electric motor. Such a power conversion device includes a voltage control section (for example, a DC/DC converter) that boosts the output voltage of the battery and outputs the boosted voltage to the motor. The voltage control unit is also called a VCU (Voltage Control Unit).

In Patent Document 1 below, when an information processing device of a navigation device mounted on an electric vehicle in which drive motors are arranged for each of four wheels searches for a guidance route to a destination, an electric vehicle is generated for the guidance route. A technique is disclosed for generating an individual usage plan for each drive motor so that the temperature rise level of each drive motor does not exceed the upper limit when an automobile is running. For example, in the invention described in Patent Document 1 below, when an electric vehicle runs using a plurality of drive motors, the load applied to each drive motor is distributed to suppress the temperature rise of these motors. .

Further, in Patent Document 2 below, a step-up/step-down converter provided in a hybrid vehicle, during step-up operation, converts a system voltage obtained by stepping up a DC voltage (battery voltage) supplied from a running battery to different motor generators. A technique is disclosed in which power is supplied in common to a plurality of inverters provided as a unit.

JP 2010-226880 A JP 2007-325351 A

When a plurality of electric motors are provided in a vehicle, the optimum input voltages for the respective electric motors may differ from each other due to the difference in physical size and operating conditions of the respective electric motors. For this reason, for example, if an optimum input voltage for one of the plurality of electric motors is commonly supplied to each of the plurality of electric motors, the input voltage for the other electric motors of the plurality of electric motors will not be optimum. will be supplied, and the increase in losses due to that input voltage will tend to cause other motors to become hot. On the other hand, if a voltage control section is provided for each of a plurality of electric motors, the optimum input voltage can be supplied to each electric motor. As the number increases, the configuration of the vehicle becomes complicated.

SUMMARY OF THE INVENTION The present invention provides a vehicle capable of suppressing a plurality of electric motors from reaching a high temperature state while suppressing complication of the configuration of the vehicle.

One aspect of the present invention is
a battery, a plurality of electric motors including an electric motor that drives drive wheels, a power conversion device that converts power exchanged between the battery and the plurality of electric motors, and a control device that controls the power conversion device a vehicle comprising
The power conversion device has a voltage control unit that supplies a boosted voltage obtained by boosting the output voltage of the battery to the plurality of electric motors,
The control device is
deriving an estimated rotation speed, which is an estimated rotation speed value, and an estimated torque, which is an estimated output torque value, of the plurality of electric motors when the vehicle travels along a predetermined planned travel route;
deriving an estimated boosted voltage, which is an estimated value of the boosted voltage when traveling on the planned travel route, based on the estimated rotational speed and the estimated torque;
estimating temperatures of the plurality of electric motors when the estimated boosted voltage is supplied to the plurality of electric motors;
when the temperature of any one of the estimated temperatures of the plurality of electric motors exceeds a threshold, deriving a corrected boosted voltage obtained by correcting the estimated boosted voltage so as to suppress the temperature rise of the electric motor; controlling the boosted voltage when traveling the planned travel route based on the derived corrected boosted voltage;
is a vehicle.

Advantageous Effects of Invention According to the present invention, it is possible to provide a vehicle capable of suppressing a plurality of electric motors from reaching a high temperature state while suppressing complexity of the configuration of the vehicle.

It is a figure showing a schematic structure of vehicles 10 which are one embodiment of the present invention. FIG. 2 is a diagram showing an electrical connection relationship among battery BAT of vehicle 10, power conversion device 11, first motor generator MG1, and second motor generator MG2. 3 is a flowchart showing an example of processing executed by a control device 20 of vehicle 10. FIG. 2 is a diagram showing an example of specific control by a control device 20 of vehicle 10. FIG. It is a figure which shows typically an example of the effect by this embodiment.

Hereinafter, one embodiment of the vehicle of the present invention will be described in detail with reference to the drawings. It should be noted that the drawings are viewed in the direction of the reference numerals. Also, hereinafter, the same or similar elements may be denoted by the same or similar reference numerals, and the description thereof may be omitted or simplified as appropriate.

[vehicle]
As shown in FIG. 1, a vehicle 10 according to one embodiment of the present invention is a hybrid electric vehicle, and includes an engine ENG, a first motor generator MG1, a second motor generator MG2, and a battery BAT. , a clutch CL, a power conversion device 11, various sensors 12, a navigation device 13, a display device 14, and a control device 20. In FIG. 1, thick solid lines indicate mechanical connections, double dotted lines indicate electrical wiring, and thin solid arrows indicate transmission and reception of control signals or detection signals.

Engine ENG is, for example, a gasoline engine or a diesel engine, and outputs power generated by burning supplied fuel. Engine ENG is coupled to second motor generator MG2 and is coupled to drive wheels DW of vehicle 10 via clutch CL. The power output by the engine ENG (hereinafter also referred to as "the output of the engine ENG") is transmitted to the second motor generator MG2 when the clutch CL is in the disengaged state, and is transmitted to the second motor generator MG2 when the clutch CL is in the engaged state (engaged state). is transmitted to the second motor generator MG2 and the drive wheels DW. Second motor generator MG2 and clutch CL will be described later.

The first motor-generator MG1 is a motor-generator (so-called traction motor) mainly used as a drive source for the vehicle 10, and is composed of, for example, an AC motor. First motor generator MG1 is electrically connected to battery BAT and second motor generator MG2 via power conversion device 11 . Power from at least one of battery BAT and second motor generator MG2 can be supplied to first motor generator MG1. First motor generator MG1 operates as an electric motor when supplied with electric power, and outputs power for vehicle 10 to run. Further, the first motor generator MG1 is coupled to the drive wheels DW, and the power output by the first motor generator MG1 (hereinafter also referred to as "the output of the first motor generator MG1") is transmitted to the drive wheels DW. Vehicle 10 runs when at least one of the output of engine ENG and the output of first motor generator MG1 is transmitted to drive wheels DW.

Further, the first motor generator MG1 performs regenerative operation as a generator to generate power (so-called regenerative power generation) when the vehicle 10 is braked (when it is rotated by the engine ENG or the drive wheels DW). Electric power generated by the regenerative operation of the first motor generator MG1 (hereinafter also referred to as “regenerative electric power”) is supplied to the battery BAT via the power conversion device 11, for example. Thereby, the battery BAT can be charged with the regenerated power.

Further, the regenerated electric power may be supplied to the second motor generator MG2 via the power conversion device 11 without being supplied to the battery BAT. By supplying the regenerated electric power to the second motor generator MG2, it is possible to "discharge" the regenerated electric power to consume the regenerated electric power without charging the battery BAT. It should be noted that the regenerated electric power supplied to the second motor generator MG2 is used to drive the second motor generator MG2 when power is discharged, and the power generated thereby is input to the engine ENG, resulting in mechanical friction loss of the engine ENG. Consumed by etc.

The second motor-generator MG2 is a motor-generator that is mainly used as a power generator, and is composed of, for example, an AC motor. The second motor generator MG2 is driven by the power of the engine ENG to generate power. Electric power generated by second motor generator MG2 is supplied via power conversion device 11 to at least one of battery BAT and first motor generator MG1. By supplying the power generated by the second motor generator MG2 to the battery BAT, the battery BAT can be charged with the power. Further, by supplying the electric power generated by the second motor generator MG2 to the first motor generator MG1, the electric power can drive the first motor generator MG1.

The power conversion device 11 is a device (a so-called power control unit, also referred to as a “PCU”) that converts input power and outputs the converted power. BAT is connected. For example, the power conversion device 11 includes a first inverter 111 , a second inverter 112 and a voltage control device 110 . First inverter 111, second inverter 112, and voltage control device 110 are electrically connected to each other.

The voltage control device 110 functions as a voltage control section that converts an input voltage and outputs the converted voltage. A DC/DC converter or the like can be used as the voltage control device 110 . Voltage control device 110 boosts the output voltage of battery BAT and outputs it to first inverter 111, for example, when supplying power from battery BAT to first motor generator MG1. Further, for example, when first motor generator MG1 performs regenerative power generation, voltage control device 110 steps down the output voltage of first motor generator MG1 received via first inverter 111, and transfers the voltage to battery BAT. Output. When second motor generator MG2 generates power, voltage control device 110 steps down the output voltage of second motor generator MG2 received via second inverter 112 and outputs the voltage to battery BAT.

When first inverter 111 supplies power from battery BAT to first motor generator MG1, first inverter 111 converts power (direct current) from battery BAT received via voltage control device 110 into alternating current to supply power to first motor generator MG1. Output to Further, when first motor generator MG1 performs regenerative power generation, first inverter 111 converts the electric power (AC) received from first motor generator MG1 into direct current and outputs the direct current to voltage control device 110 . Further, first inverter 111 converts the electric power (AC) received from first motor generator MG1 into direct current and outputs the direct current to second inverter 112 when regenerative electric power of first motor generator MG1 is discharged.

When second motor generator MG2 generates power, second inverter 112 converts electric power (AC) received from second motor generator MG2 into direct current and outputs the direct current to voltage control device 110 . Second inverter 112 converts the regenerated electric power (direct current) of first motor generator MG1 received via first inverter 111 into alternating current when the regenerated electric power of first motor generator MG1 is discharged. Output to the second motor generator MG2.

The battery BAT is a rechargeable secondary battery, and has a plurality of storage cells connected in series or in series-parallel. The battery BAT is configured to be capable of outputting a high voltage such as 100 to 400 [V]. A lithium ion battery, a nickel metal hydride battery, or the like can be used as a storage cell of the battery BAT.

Clutch CL can take a connected state in which the power transmission path from engine ENG to drive wheels DW is connected (fastened) and a disconnected state in which the power transmission path from engine ENG to drive wheels DW is disconnected (disconnected). The output of the engine ENG is transmitted to the driving wheels DW when the clutch CL is in the engaged state, and is not transmitted to the driving wheels DW when the clutch CL is in the disengaged state.

Various sensors 12 include, for example, a vehicle speed sensor that detects the running speed of the vehicle 10 (hereinafter also referred to as "vehicle speed"), an accelerator position (hereinafter also referred to as "AP") sensor that detects the amount of operation of the accelerator pedal of the vehicle 10, a battery It includes a battery sensor that detects various types of information about the BAT (for example, the output voltage of the battery BAT, charging/discharging current, and temperature). Detection results by the various sensors 12 are transmitted to the control device 20 as detection signals.

The navigation device 13 includes a storage device (for example, a flash memory) for storing map data and the like, and a GNSS (Global Navigation System) capable of specifying the position of the vehicle 10 (hereinafter also referred to as "vehicle position") based on signals received from positioning satellites. satellite system) receiver, a display for displaying various information, operation buttons (including a touch panel) for accepting operations from a user (a passenger of the vehicle 10, such as a driver; the same applies to the following description), and the like.

The map data stored by the navigation device 13 includes road data relating to roads. For example, in road data, each road is divided into predetermined sections. The road data includes information on links corresponding to each section and nodes connecting the links. In addition, the road data is associated with each link and provided with attribute information indicating the distance of the section corresponding to the link, speed limit (for example, legal speed), road gradient (for example, inclination angle), and the like.

The navigation device 13 determines a route (hereinafter also referred to as a “guidance route”) from the current position of the vehicle 10 to the destination set by the user of the vehicle 10, for example, by referring to map data or the like. Then, the user is guided by displaying the determined guidance route on the display.

Further, the navigation device 13 predicts the planned travel route of the vehicle 10 by referring to the vehicle position, the traveling direction of the vehicle 10, the set destination, map data, and the like. As an example, the navigation device 13 travels in a section (for example, a section up to 10 [km] ahead in the direction of travel) within a predetermined range from the position of the vehicle 10 in the direction of travel (that is, in front of the vehicle). Predict as scheduled route.

After predicting the planned travel route, the navigation device 13 transmits route information about the planned travel route to the control device 20 . This route information includes information indicating each section included in the planned travel route and attribute information for each section. Thereby, the navigation device 13 can notify the control device 20 of each section included in the planned travel route, the speed limit of the section, the road gradient, and the like. The navigation device 13 also notifies the control device 20 of the position of the vehicle as appropriate.

Furthermore, the navigation device 13 may be configured to be capable of receiving road traffic information including congestion information, and may transmit the received road traffic information to the control device 20 . In this way, the navigation device 13 can notify the control device 20 of the traffic congestion situation on the planned travel route.

The display device 14 is a display device capable of displaying various types of information about the vehicle 10, and is, for example, a liquid crystal display called a "multi-information display." The information displayed by the display device 14 includes, for example, information indicating the remaining capacity of the battery BAT (hereinafter also referred to as "remaining capacity information") and information indicating the cruising distance of the vehicle 10 (hereinafter also referred to as "cruising distance information"). ) etc. can be mentioned. The information displayed by the display device 14 is not limited to the remaining capacity information and the cruising range information, and may be other information such as the temperature around the vehicle 10 (so-called "outside temperature"). Moreover, the display device 14 is not limited to a liquid crystal display, and may be another type of display device such as a lamp display.

The control device 20 includes, for example, a processor that performs various calculations, a storage device that has a non-transitory storage medium that stores various information, an input/output device that controls input/output of data between the inside and outside of the control device 20, and the like. It is a device (computer) that is realized by an ECU (Electronic Control Unit) that controls the entire vehicle 10 . The control device 20 may be realized by one ECU or may be realized by a plurality of ECUs.

Specifically, the control device 20 is provided so as to communicate with the engine ENG, the clutch CL, the power conversion device 11, the various sensors 12, the navigation device 13, and the display device . The control device 20 controls the output of the engine ENG, controls the power conversion device 11 to control the outputs of the first motor generator MG1 and the second motor generator MG2, and controls the state of the clutch CL. or Thereby, the control device 20 can control the driving mode of the vehicle 10 as described later. The control device 20 also controls the display device 14 to display, for example, remaining capacity information and cruising distance information corresponding to the remaining capacity of the battery BAT at that time.

[Vehicle driving mode]
Next, driving modes of the vehicle 10 will be described. The vehicle 10 can take an EV driving mode, a hybrid driving mode, and an engine driving mode as driving modes. Then, the vehicle 10 runs in one of these running modes. The control device 20 controls in which driving mode the vehicle 10 is driven.

[EV driving mode]
The EV running mode is a running mode in which only the electric power of battery BAT is supplied to first motor generator MG1, and vehicle 10 is run by power output from first motor generator MG1 in accordance with the electric power. This EV running mode is an example of a first running mode in the present invention.

Specifically, in the case of the EV running mode, the control device 20 disengages the clutch CL. In the case of the EV traveling mode, control device 20 stops the supply of fuel to engine ENG to stop the output of power from engine ENG (hereinafter also referred to as "operation of engine ENG"). Therefore, in the EV running mode, power generation by the second motor generator MG2 is not performed. In the case of the EV traveling mode, the control device 20 supplies only the electric power of the battery BAT to the first motor generator MG1, and causes the first motor generator MG1 to output power corresponding to the electric power. Run 10.

For example, the first motor generator MG1 is supplied with electric power only from the battery BAT, and the control device 20 generates the driving force ( The vehicle 10 is driven in the EV driving mode on condition that the required driving force is obtained.

Note that in the EV travel mode, the supply of fuel to the engine ENG is stopped. improves fuel efficiency. Therefore, by increasing the frequency (opportunities) of setting the vehicle 10 to the EV driving mode, it is possible to improve the fuel efficiency of the vehicle 10 . On the other hand, in the EV driving mode, the second motor generator MG2 does not generate power, and the first motor generator MG1 is driven only by the electric power of the battery BAT. ) is likely to decrease.

[Hybrid driving mode]
The hybrid running mode is a running mode in which at least the electric power generated by the second motor-generator MG2 is supplied to the first motor-generator MG1, and the power output by the first motor-generator MG1 in accordance with the electric power is mainly used to drive the vehicle 10. .

Specifically, in the case of the hybrid running mode, the control device 20 disengages the clutch CL. In the hybrid running mode, control device 20 supplies fuel to engine ENG, causes engine ENG to output power, and drives second motor generator MG2 with the power of engine ENG. Thus, in the hybrid running mode, power is generated by the second motor generator MG2. In the case of the hybrid traveling mode, the control device 20 disconnects the power transmission path by the clutch CL, supplies the electric power generated by the second motor generator MG2 to the first motor generator MG1, and outputs power according to the electric power. The power is output from the first motor generator MG1, and the vehicle 10 is driven by the power.

The power supplied from second motor generator MG2 to first motor generator MG1 is greater than the power supplied from battery BAT to first motor generator MG1. Therefore, in the hybrid running mode, the output of the first motor generator MG1 can be increased compared to the EV running mode, and the driving force for running the vehicle 10 (hereinafter also referred to as "the output of the vehicle 10") is large. can be obtained.

In the case of the hybrid running mode, control device 20 may also supply electric power from battery BAT to first motor generator MG1 as necessary. That is, control device 20 may supply electric power from both second motor generator MG2 and battery BAT to first motor generator MG1 in the hybrid running mode. As a result, the electric power supplied to the first motor-generator MG1 can be increased compared to the case where only the electric power of the second motor-generator MG2 is supplied to the first motor-generator MG1. power can be obtained.

[Engine running mode]
The engine driving mode is a driving mode in which the vehicle 10 is driven mainly by the power output by the engine ENG.

Specifically, in the engine running mode, the control device 20 connects the clutch CL. In addition, in the engine running mode, the control device 20 supplies fuel to the engine ENG and causes the engine ENG to output power. In the engine running mode, the power transmission path is connected by the clutch CL, so the power of the engine ENG is transmitted to the driving wheels DW to drive the driving wheels DW. In this manner, in the engine running mode, the control device 20 outputs power from the engine ENG, and drives the vehicle 10 with the power.

In the case of the engine running mode, control device 20 may supply electric power of battery BAT to first motor generator MG1 as necessary. As a result, in the engine running mode, the power supplied from the battery BAT can also be used to drive the vehicle 10 using the power output from the first motor generator MG1, and the vehicle 10 can be driven only by the power of the engine ENG. As compared with the case, a much larger driving force can be obtained as an output of the vehicle 10 . Further, as a result, the output of the engine ENG can be suppressed and the fuel efficiency of the vehicle 10 can be improved, compared to the case where the vehicle 10 is driven only by the power of the engine ENG.

[Electrical Connection Relationship Between Battery, Power Conversion Device, and Each Motor Generator]
Next, an example of the electrical connection relationship between battery BAT, power converter 11, first motor generator MG1 and second motor generator MG2 will be described. As shown in FIG. 2, the voltage control device 110 of the power conversion device 11 uses the V1 voltage, which is the output voltage of the battery BAT, as the input voltage, and turns on and off the two switching elements to change the V2 voltage on the output side to V1 It is possible to boost the voltage to a voltage higher than the voltage. Note that the V2 voltage is equal to the V1 voltage when the two switching elements of the voltage control device 110 do not switch on and off.

First inverter 111 converts a DC voltage into an AC voltage and supplies a three-phase current to first motor generator MG1. The first inverter 111 also converts the AC voltage generated by the first motor generator MG1 during braking of the vehicle 1 into a DC voltage. Second inverter 112 converts an AC voltage generated by second motor generator MG2 by driving engine ENG into a DC voltage. Second inverter 112 converts the DC voltage generated by first motor generator MG1 and converted by first inverter 111 during braking of vehicle 1 into AC voltage, and supplies a three-phase current to second motor generator MG2. may

Thus, in vehicle 10, voltage V2 as a boosted voltage obtained by boosting voltage V1 as the output voltage of battery BAT by single voltage control device 110 is applied to first motor generator MG1 and second motor generator MG1. It is made to be supplied in common to the generator MG2. Thus, the single voltage control device 110 can supply the V2 voltage required to drive the first motor generator MG1 and the second motor generator MG2 respectively. Therefore, the number of required voltage control devices 110 can be reduced compared to the case where the voltage control device 110 corresponding to each motor generator is individually provided, and the complexity of the configuration of the vehicle 10 can be suppressed. .

[Example of control performed by control device]
The optimum V2 voltage for the first motor-generator MG1 and the optimum V2 voltage for the second motor-generator MG2 may be different from each other due to the difference in physique, operating state, etc. between the first motor-generator MG1 and the second motor-generator MG2. It can be different.

For example, when the vehicle 1 is cruising at high speed in the hybrid traveling mode, the first motor generator MG1 is operated at high rotation and low output. Thus, when the first motor generator MG1 is operated at high speed and low output, the first motor generator MG1 requires a relatively large V2 voltage. On the other hand, the second motor generator MG2 is operated in consideration of the BSFC (Brake Specific Fuel Consumption) of the engine ENG, so unlike the first motor generator MG1, it does not require such a large V2 voltage.

Generally, in such a case, from the viewpoint of ensuring the required driving force of the vehicle 1, the control device 20 reduces the V2 voltage required by the first motor generator MG1 (that is, the relatively large V2 voltage) to the power The voltage is supplied from the conversion device 11 (voltage control device 110) to the first motor generator MG1 and the second motor generator MG2. Therefore, at this time, an excessive V2 voltage is supplied to the second motor generator MG2, and this V2 voltage increases the loss and heat generation of the second motor generator MG2. If such a state continues for a long period of time, the second motor generator MG2 may reach a high temperature state. However, from the viewpoint of preventing deterioration and damage, it is not preferable for each motor generator including the second motor generator MG2 to be in a high temperature state.

Therefore, control device 20 controls voltage control device 110 so as to switch between the optimum V2 voltage for first motor generator MG1 and the optimum V2 voltage for second motor generator MG2. First motor generator MG1 and second motor generator MG2 are prevented from reaching a high temperature state due to heat generation.

More specifically, the control device 20 controls an estimated rotation speed (for example, an estimated motor rotation speed N_est, which will be described later), which is an estimated rotation speed of each motor generator when the vehicle 10 travels along a predetermined planned travel route. , and an estimated torque (for example, an estimated motor torque Trq_est, which will be described later), which is an estimated value of the output torque. Next, the control device 20 derives an estimated boosted voltage (for example, an estimated boosted voltage V2_est1, which will be described later), which is an estimated value of the V2 voltage when the vehicle travels along the planned travel route, based on the derived estimated rotation speed and estimated torque. . Then, control device 20 estimates the temperature of each motor generator (for example, motor temperature T_est, which will be described later) when the derived estimated boosted voltage is supplied to each motor generator, and selects one of the estimated temperatures of each motor generator. When the temperature of the motor generator exceeds the threshold value, a corrected boosted voltage (for example, a corrected boosted voltage V2_est2 described later) is derived by correcting the estimated boosted voltage so as to suppress the temperature rise of the motor generator, and the derived corrected boosted voltage Based on the voltage, the V2 voltage is controlled when traveling the planned travel route. As a result, when the vehicle 10 travels along the predetermined travel route, it is possible to prevent the first motor-generator MG1 and the second motor-generator MG2 from reaching a high temperature state due to the heat generated by the voltage V2. .

[Example of processing executed by control device]
An example of the processing executed by the control device 20 will be specifically described below with reference to FIGS. 3 and 4. FIG. For example, the control device 20 acquires the route information of the planned travel route of the vehicle 10 from the navigation device 13 at a predetermined cycle, and executes the series of processes shown in FIG. 3 each time the route information of the planned travel route is acquired.

As shown in FIG. 3, the control device 20 refers to the route information of the planned travel route of the vehicle 10 acquired from the navigation device 13, and determines the number of rotations of each motor generator when the vehicle 1 travels along the planned travel route. , and an estimated motor torque Trq_est, which is an estimated value of the output torque, are derived (step S1).

In the present embodiment, by the process of step S1, the estimated motor rotation speed N_est1, which is the estimated motor rotation speed N_est for the first motor generator MG1, and the estimated motor rotation speed N_est, which is the estimated motor rotation speed N_est for the second motor generator MG2. N_est2, a motor estimated torque Trq_est1 that is the motor estimated torque Trq_est for the first motor generator MG1, and a motor estimated torque Trq_est2 that is the motor estimated torque Trq_est for the second motor generator MG2 are derived.

An example of the estimated motor rotation speed N_est1 derived by the control device 20 through the process of step S1 is indicated by a solid line 400 in FIG. 4(b). In FIG. 4(b), the vertical axis represents the rotation speed, and the horizontal axis represents the timing.

As indicated by a solid line 400, the control device 20, for example, determines the timing of the estimated motor rotation speed N_est1 during a future predetermined period in which the vehicle 1 can travel along a predetermined planned travel route (hereinafter also referred to as "process target period"). Derive a time chart that represents the transition. Further, although illustration and detailed description are omitted, the control device 20 also performs step It is derived by the process of S1.

Note that the estimated motor rotation speed N_est (for example, the estimated motor rotation speed N_est1) at each time can be derived based on the vehicle speed at the corresponding time, for example. The vehicle speed at each period can be predicted, for example, based on the attribute information of each section (for example, the speed limit of each section) included in the route information of the planned travel route acquired from the navigation device 13 . Also, the processing target period can be set to a period of a length predetermined by the manufacturer of the control device 20 or the like, for example.

An example of the estimated motor torque Trq_est1 derived by the control device 20 through the process of step S1 is indicated by a solid line 410 in FIG. 4(c). In FIG. 4(c), the vertical axis represents torque and the horizontal axis represents timing.

As indicated by a solid line 410, the control device 20 derives, for example, a time chart representing the temporal transition of the estimated motor torque Trq_est1 during the processing target period. Further, although illustration and detailed description are omitted, the control device 20 also generates the time chart representing the temporal transition of the estimated motor torque Trq_est2 in the processing target period in the same manner as the time chart of the estimated motor torque Trq_est1 in step S1. Derived by processing.

Note that the estimated motor torque Trq_est (for example, the estimated motor torque Trq_est1) at each time can be derived based on, for example, the required driving force of the vehicle 1 at the corresponding time. The required driving force at each time period can be predicted based on, for example, the vehicle speed at each time period, the road gradient of the section traveled at each time period, and the like.

Next, based on the estimated motor rotation speed N_est and the estimated motor torque Trq_est derived by the process of step S1, the control device 20 sets the estimated boosted voltage V2_est1, which is the estimated value of the V2 voltage when the vehicle 1 travels along the planned travel route. is derived (step S2).

An example of the estimated boosted voltage V2_est1 derived by the control device 20 through the process of step S2 is indicated by a dashed line 420 in FIG. 4(d). In FIG. 4D, the vertical axis represents voltage and the horizontal axis represents time.

As indicated by a dashed line 420, the control device 20 derives, for example, a time chart representing the temporal transition of the estimated boosted voltage V2_est1 during the processing target period. The estimated boosted voltage V2_est1 at each time can be derived based on, for example, the estimated motor rotation speed N_est and the estimated motor torque Trq_est at the corresponding time.

More specifically, in this embodiment, it is assumed that the MG1 side V2 voltage estimation map and the MG2 side V2 voltage estimation map are stored in advance in the control device 20 . Here, the map for estimating the MG1 side V2 voltage is the relationship between the rotational speed and output torque of the first motor generator MG1 and the V2 voltage required to operate the first motor generator MG1 at the rotational speed and output torque. It is a map (information) that represents The MG2-side V2 voltage estimation map shows the relationship between the rotation speed and output torque of the second motor generator MG2 and the V2 voltage required to drive the second motor generator MG2 at that rotation speed and output torque. It is a map that represents

Then, the control device 20 refers to the MG1 side V2 voltage estimation map, and based on the estimated motor rotation speed N_est1 and the estimated motor torque Trq_est1 derived by the process of step S1, the first A V2 voltage required to drive the motor generator MG1 is derived. Further, the control device 20 refers to the MG2 side V2 voltage estimation map, and based on the estimated motor rotation speed N_est2 and the estimated motor torque Trq_est2 derived by the process of step S1, the second A V2 voltage required to drive the motor generator MG2 is derived. Then, control device 20 compares the V2 voltage required to drive first motor generator MG1 and the V2 voltage required to drive second motor generator MG2 corresponding to the same period, One of them is adopted as the estimated boosted voltage V2_est1 at that time.

Note that the V2 voltage required to drive the first motor generator MG1 is normally higher than the V2 voltage required to drive the second motor generator MG2. Therefore, as the estimated boosted voltage V2_est1, the V2 voltage necessary for driving the first motor generator MG1 is normally employed.

Next, control device 20 estimates motor temperature T_est, which is an estimated value of the temperature of each motor generator when estimated boosted voltage V2_est1 derived by the process of step S2 is supplied to each motor generator (step S3).

In the present embodiment, a motor temperature T_est1, which is the motor temperature T_est for the first motor generator MG1, and a motor temperature T_est2, which is the motor temperature T_est for the second motor generator MG2, are derived by the process of step S3.

An example of the motor temperature T_est2 derived by the control device 20 through the process of step S3 is indicated by a dashed line 430 in FIG. 4(a). In FIG. 4A, the vertical axis represents temperature, and the horizontal axis represents time.

As indicated by a dashed line 430, the control device 20 derives, for example, a time chart representing the temporal transition of the motor temperature T_est2 during the processing target period. The motor temperature T_est2 at each time can be derived based on, for example, the estimated motor rotation speed N_est2, the estimated motor torque Trq_est2, and the estimated boosted voltage V2_est1 at the corresponding time.

Further, although illustration and detailed description are omitted, the control device 20 performs the process of step S3 to generate a time chart representing the temporal transition of the motor temperature T_est1 during the processing target period, similarly to the time chart of the motor temperature T_est2. derive The motor temperature T_est1 at each time can be derived based on, for example, the estimated motor rotation speed N_est1, the estimated motor torque Trq_est1, and the estimated boosted voltage V2_est1 at the corresponding time.

Next, the control device 20 determines whether or not the motor temperature T_est derived by the process of step S3 exceeds a predetermined threshold (step S4). Here, the threshold value is, for example, a predetermined value predetermined by the manufacturer of control device 20 or the like corresponding to each motor generator. This threshold value is determined, for example, in consideration of the heat resistance performance of each motor generator.

In the present embodiment, for example, it is assumed that Tth shown in FIG. The time chart of the motor temperature T_est2 indicated by the dashed line 430 exceeds Tth during the period Tm during the processing target period. In such a case, the control device 20 determines in the process of step S4 that the motor temperature T_est exceeds the threshold (step S4: Yes), and proceeds to the process of step S5.

On the other hand, if all the motor temperatures T_est derived by the process of step S3 are equal to or less than the threshold, the control device 20 determines in the process of step S4 that the motor temperature T_est does not exceed the threshold (step S4 : No), the process proceeds to step S6.

When it is determined that the motor temperature T_est derived by the process of step S3 exceeds the threshold, the control device 20 performs the process of step S2 so as to suppress the temperature rise of the motor generator predicted that the motor temperature T_est exceeds the threshold. A corrected boosted voltage V2_est2 is derived by correcting the estimated boosted voltage V2_est1 derived by (step S5).

In the example shown in FIG. 4, motor temperature T_est2 corresponding to second motor generator MG2 exceeds Tth in period Tm. In such a case, control device 20 derives corrected boosted voltage V2_est2 by correcting estimated boosted voltage V2_est1 so as to suppress temperature rise of second motor generator MG2 in the process of step S5.

More specifically, for example, as indicated by the white arrow α and the solid line 431 in FIG. 4A and the white arrow β and the solid line 421 in FIG. In order that the motor temperature T_est2 at Tm does not exceed Tth, the corrected boosted voltage V2_est2 is derived by making the voltage during the period Tm smaller than the estimated boosted voltage V2_est1.

Incidentally, in FIG. 4(c), the dashed line 411 indicates the upper limit of the output torque that the first motor generator MG1 can output according to the V2 voltage considering the temperature of each motor generator (hereinafter also referred to as "MG1 outline torque"). is shown. If the required driving force of the vehicle 1 cannot be ensured due to the decrease in the MG1 outline torque, so-called "sluggishness (also referred to as hesitation)" may occur and the drivability of the vehicle 10 may deteriorate.

Therefore, control device 20 sets corrected boosted voltage V2_est2 to a voltage that allows first motor generator MG1 to output the required driving force of vehicle 1 . More specifically, as indicated by a broken line 411 and a white arrow γ in FIG. A corrected boosted voltage V2_est2 that reduces the torque as much as possible is derived. As a result, for example, in period Tm, it is possible to prevent the first motor generator MG1 from outputting the required driving force of the vehicle 1 while suppressing the temperature rise of the second motor generator MG2.

Based on the estimated boosted voltage V2_est1 derived by the process of step S2 or the corrected boosted voltage V2_est2 derived by the process of step S5, the control device 20 controls the V2 voltage when the vehicle 10 travels along the planned travel route. (Step S6), the series of processes shown in FIG. 3 is terminated.

For example, control device 20 controls voltage control device 110 to generate V2 voltage according to estimated boosted voltage V2_est1 derived by the process of step S2 if the process of step S5 is not executed. Thus, in this case, V2 voltage corresponding to estimated boosted voltage V2_est1 derived from estimated motor rotation speed N_est and estimated motor torque Trq_est can be supplied to first motor generator MG1 and second motor generator MG2. Therefore, for example, the MG1 outline torque can be maintained at a high level, enabling the first motor generator MG1 to more reliably output the required driving force of the vehicle 1 .

On the other hand, if control device 20 has executed the process of step S5, control device 20 controls voltage control device 110 to generate voltage V2 according to corrected boosted voltage V2_est2 derived by the process of step S5. Accordingly, in this case, for example, the temperature rise of the second motor generator MG2 during the period Tm can be suppressed so that the temperature of the second motor generator MG2 does not exceed Tth even during the period Tm.

[Example of effects of the present embodiment]
Finally, with reference to FIG. 5, an example of the effects of this embodiment will be described. For example, it is assumed that the optimum V2 voltage for the first motor generator MG1 is always supplied to the first motor generator MG1 and the second motor generator MG2. In this case, as shown in FIG. 5A, the heat generation of the first motor generator MG1 can be suppressed, so the temperature of the first motor generator MG1 can be suppressed below the predetermined protection line. However, in this case, heat generation of the second motor-generator MG2 increases, so it becomes difficult to keep the temperature of the second motor-generator MG2 below the protective line.

On the other hand, it is assumed that the optimum V2 voltage for the second motor generator MG2 is always supplied to the first motor generator MG1 and the second motor generator MG2. In this case, as shown in FIG. 5B, the heat generation of the second motor generator MG2 can be suppressed, so the temperature of the second motor generator MG2 can be suppressed below the protection line. However, in this case, since the heat generation of the first motor generator MG1 increases, it becomes difficult to keep the temperature of the first motor generator MG1 below the protective line.

In contrast, according to the present embodiment, as described above, the voltage control device 110 is configured to appropriately switch between the optimum V2 voltage for the first motor generator MG1 and the optimum V2 voltage for the second motor generator MG2. By controlling, as shown in FIG. 5(C), it is possible to suppress the temperatures of both the first motor generator MG1 and the second motor generator MG2, which may have different operating states, to below the protection line. As a result, for example, when the temperature of the first motor-generator MG1 or the second motor-generator MG2 exceeds the protection line, even if a power-saving mode is provided to limit the output of these to protect them, the power-saving It is possible to reduce the frequency of mode transitions. Therefore, it is possible to reduce the chances that the first motor-generator MG1 or the second motor-generator MG2 cannot exhibit its original output performance, and the marketability of the vehicle 10 can be improved.

As described above, according to the present embodiment, it is possible to prevent both the first motor-generator MG1 and the second motor-generator MG2 from reaching a high temperature state while preventing the configuration of the vehicle 10 from becoming complicated. .

Although one embodiment of the present invention has been described above with reference to the drawings, it goes without saying that the present invention is not limited to such an example. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope described in the claims, and these also belong to the technical scope of the present invention. Understood. Moreover, each component in the above-described embodiments may be combined arbitrarily without departing from the gist of the invention.

For example, in the above-described embodiment, the first motor generator MG1 is a motor generator used as a drive source for the vehicle 10, and the second motor generator MG2 is a motor generator used as a power generator, but the present invention is not limited to this. For example, the first motor generator MG1 is a motor generator that drives one of the front wheels and the rear wheels of the vehicle 10, and the second motor generator MG2 is a motor generator that drives the other of the front wheels and the rear wheels of the vehicle 10. It is good also as a motor generator which drives.

Further, in the above-described embodiment, an example in which the present invention is applied to the vehicle 10, which is a hybrid electric vehicle, has been described, but the present invention is not limited to this. The present invention provides a battery, a plurality of electric motors including an electric motor for driving a drive wheel, a power conversion device for converting power exchanged between the battery and the plurality of electric motors, and a control device for controlling the power conversion device. , and can be applied to electric vehicles (for example, Battery Electric Vehicles) and fuel cell electric vehicles (Fuel Cell Electric Vehicles).

At least the following matters are described in this specification and the like. Components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

(1) A battery (battery BAT), a plurality of electric motors (first motor generator MG1, second motor generator MG2) including an electric motor (first motor generator MG1) that drives drive wheels, the battery and the plurality of electric motors A vehicle (vehicle 10) comprising a power conversion device (power conversion device 11) that converts power exchanged between and a control device (control device 20) that controls the power conversion device,
The power conversion device has a voltage control unit (voltage control device 110) that supplies a boosted voltage obtained by boosting the output voltage of the battery to the plurality of electric motors,
The control device is
deriving an estimated rotation speed, which is an estimated rotation speed value, and an estimated torque, which is an estimated output torque value, of the plurality of electric motors when the vehicle travels along a predetermined planned travel route;
deriving an estimated boosted voltage, which is an estimated value of the boosted voltage when traveling on the planned travel route, based on the estimated rotational speed and the estimated torque;
estimating temperatures of the plurality of electric motors when the estimated boosted voltage is supplied to the plurality of electric motors;
When the temperature of any one of the estimated temperatures of the plurality of electric motors exceeds a threshold value, a corrected boosted voltage obtained by correcting the estimated boosted voltage so as to suppress the temperature rise of the electric motor is derived. controlling the boosted voltage when traveling the planned travel route based on the corrected boosted voltage that has been set;
vehicle.

According to (1), it is possible to prevent the plurality of electric motors from being in a high temperature state while preventing the configuration of the vehicle from becoming complicated.

(2) The vehicle according to (1),
the corrected boosted voltage is smaller than the estimated boosted voltage;
vehicle.

According to (2), if the estimated boosted voltage is supplied to a plurality of electric motors, the boosted voltage is controlled based on the corrected boosted voltage that is smaller than the estimated boosted voltage when it is expected that one of the motors will be in a high temperature state. Therefore, it is possible to prevent a plurality of electric motors from reaching a high temperature state.

(3) The vehicle according to (2),
The corrected boosted voltage is a voltage that allows an electric motor that drives the drive wheels to output the driving force required for running the vehicle.
vehicle.

According to (3), it is possible to suppress the plurality of electric motors from being in a high temperature state while not preventing the electric motors for driving the drive wheels from outputting the driving force required for running the vehicle.

(4) The vehicle according to any one of (1) to (3),
The control device is
If the temperature of any one of the estimated temperatures of the plurality of electric motors does not exceed the threshold value, the boosted voltage when traveling the planned travel route is controlled based on the estimated boosted voltage.
vehicle.

According to (4), when it is expected that even if the estimated boosted voltage is supplied to a plurality of electric motors, none of the motors will be in a high temperature state, the estimated boosted voltage derived from the estimated rotation speed and the estimated torque is A boosted voltage can be supplied to a plurality of electric motors.

(5) A vehicle according to any one of (1) to (4),
The vehicle further comprises an internal combustion engine (engine ENG),
The plurality of electric motors include a first electric motor (first motor generator MG1) that drives the drive wheels, and a second electric motor (second motor generator MG2) that generates power by being driven by the internal combustion engine. ,including,
vehicle.

According to (5), both the first electric motor and the second electric motor, which may be operating in different states, can be prevented from reaching a high temperature state.

10 vehicle 11 power conversion device 110 voltage control device (voltage control unit)
ENG engine (internal combustion engine)
MG1 First motor generator (motor)
MG2 Second motor generator (motor)

Claims (5)

a battery, a plurality of electric motors including an electric motor that drives drive wheels, a power conversion device that converts power exchanged between the battery and the plurality of electric motors, and a control device that controls the power conversion device a vehicle comprising
The power conversion device has a voltage control unit that supplies a boosted voltage obtained by boosting the output voltage of the battery to the plurality of electric motors,
The control device is
deriving an estimated rotation speed, which is an estimated rotation speed value, and an estimated torque, which is an estimated output torque value, of the plurality of electric motors when the vehicle travels along a predetermined planned travel route;
deriving an estimated boosted voltage, which is an estimated value of the boosted voltage when traveling on the planned travel route, based on the estimated rotational speed and the estimated torque;
estimating temperatures of the plurality of electric motors when the estimated boosted voltage is supplied to the plurality of electric motors;
When the temperature of any one of the estimated temperatures of the plurality of electric motors exceeds a threshold value, a corrected boosted voltage obtained by correcting the estimated boosted voltage so as to suppress the temperature rise of the electric motor is derived. controlling the boosted voltage when traveling the planned travel route based on the corrected boosted voltage that has been set;
vehicle. A vehicle according to claim 1,
the corrected boosted voltage is smaller than the estimated boosted voltage;
vehicle. A vehicle according to claim 2,
The corrected boosted voltage is a voltage that allows an electric motor that drives the drive wheels to output the driving force required for running the vehicle.
vehicle. A vehicle according to any one of claims 1 to 3,
The control device is
If the temperature of any one of the estimated temperatures of the plurality of electric motors does not exceed the threshold value, the boosted voltage when traveling the planned travel route is controlled based on the estimated boosted voltage.
vehicle. A vehicle according to any one of claims 1 to 4,
The vehicle further comprises an internal combustion engine,
The plurality of electric motors includes a first electric motor that drives the drive wheels, and a second electric motor that generates power by being driven by the internal combustion engine.
vehicle.

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