JP2009153281A - Controller of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a torque of a second MG to a torque corresponding to a request driving torque of a vehicle as fast as possible while overvoltage is prevented when slip occurs and the request driving torque of the vehicle suddenly changes in a hybrid vehicle having a first MG which is mainly concerned with power generation and the second MG driving wheels by power generated by MG. <P>SOLUTION: When slip is detected, a control mode of second MG13 is switched to a total power priority control mode. A target torque of second MG13 is calculated so that a total power obtained by adding a power consumption of second MG13, a generated power of first MG12 and a power consumption of electric load is within a prescribed range and a change amount per prescribed period of total power is not more than a prescribed value. Thus, the target torque at the time of the total power priority control mode is set to be close to the target torque corresponding to the request driving torque of the vehicle within a range where a change of total power is suppressed and occurrence of overvoltage can be prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control apparatus for an electric vehicle including a first electric motor mainly for power generation and a second electric motor capable of driving the wheels of the vehicle by electric power generated by the electric motor.

  In recent years, the demand for hybrid vehicles has been expanding rapidly due to the social demand for low fuel consumption and low exhaust emissions. For example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2007-221894), this hybrid vehicle mainly includes an internal combustion engine and a first MG (motor generator) mainly used as a generator. A second MG used as an electric motor for driving the wheel, and the power of the internal combustion engine is divided into two systems by a power split mechanism to drive the wheel by the output of one system and the output of the other system Then, the first MG is driven, and the generated power is supplied to the second MG so that the wheels can be driven to run with the power of the second MG.

  In such a vehicle, when the slip of the wheel is detected, the torque of the second electric motor (second MG) is reduced to suppress the slip. When the torque of the motor suddenly decreases and the power consumption of the second motor rapidly decreases, the generated power of the first motor (first MG) becomes excessive with respect to the power consumption of the second motor. There is a possibility that the input voltage of the inverter that drives the electric motor 2 rapidly rises and an overvoltage is applied to the inverter.

As a countermeasure against such an overvoltage, in Patent Document 1, when it is determined that the traveling road surface of the vehicle is in a low friction coefficient state (that is, when it is predicted that a slip will occur), the input voltage of the inverter is reduced in advance. When the slip is detected, the torque of the second electric motor is reduced at a rate of change lower than normal (when no slip is detected).
JP 2007-221894A

  By the way, when slippage is detected and the required drive torque of the vehicle suddenly decreases, the torque of the second electric motor is increased to the torque corresponding to the required drive torque of the vehicle as quickly as possible within the range in which overvoltage can be prevented. It is preferable to suppress the slip by reducing the vehicle driving torque to the required driving torque as soon as possible.

  However, in the technique of the above-mentioned Patent Document 1, as shown in FIG. 5A, when slip is detected, the torque of the second electric motor is reduced at a lower rate of change than usual. There is a drawback that the torque cannot be quickly reduced to a torque corresponding to the required drive torque of the vehicle, and as a result, the drive torque of the vehicle cannot be quickly controlled to the required drive torque.

  The present invention has been made in view of such circumstances. Therefore, the object of the present invention is to prevent the occurrence of an overvoltage when the required drive torque of the vehicle changes suddenly, and as soon as possible the second. An object of the present invention is to provide a control device for an electric vehicle capable of controlling the torque of the electric motor to a torque corresponding to the required drive torque of the vehicle and improving the torque controllability.

  In order to achieve the above object, an invention according to claim 1 is an electric vehicle including a first electric motor mainly for power generation and a second electric motor capable of driving the wheels of the vehicle by electric power generated by the electric motor. In the control apparatus, the first target torque calculating means for calculating the target torque of the second electric motor (hereinafter referred to as “first target torque”) based on the required driving torque of the vehicle, and the electric power of the first electric motor The target torque of the second motor (hereinafter referred to as “second target torque” so that the total power obtained from the power of the second motor is within a predetermined range and the amount of change of the total power per predetermined period is not more than a predetermined value. A second target torque calculation means for calculating the torque of the second electric motor, and a torque priority control mode for controlling the torque of the second electric motor to be the first target torque; So that the target torque is Gosuru is obtained by the switched by the control mode switching means and the total power priority control mode.

  In this configuration, the target torque (first target torque) of the second electric motor is calculated based on the required driving torque of the vehicle by switching the control mode of the second electric motor to the torque priority control mode during normal operation. Therefore, the target torque in the torque priority control mode can be set to the first target torque corresponding to the required driving torque of the vehicle (target torque that realizes the required driving torque of the vehicle).

  When the required driving torque of the vehicle changes suddenly, the total electric power obtained from the electric power of the first electric motor and the electric power of the second electric motor is switched by switching the control mode of the second electric motor to the total electric power priority control mode. Since the target torque (second target torque) of the second electric motor can be calculated so that the (power balance) is within a predetermined range and the amount of change of the total power per predetermined period is not more than a predetermined value, The target torque in the power priority control mode is close to the target torque corresponding to the required drive torque of the vehicle (target torque in the torque priority control mode) within the range that can prevent the occurrence of overvoltage by suppressing the change in total power. Can be set to go. As a result, when the required drive torque of the vehicle changes suddenly, the torque of the second electric motor can be controlled to a torque corresponding to the required drive torque of the vehicle as quickly as possible while preventing the occurrence of overvoltage. It becomes possible to quickly control the drive torque of the vehicle to the required drive torque, thereby improving the torque controllability.

  In this case, as in claim 2, in the system in which the slip detection means for detecting the slip of the wheel is provided and the required drive torque is limited by the slip suppression control means when the slip is detected, the slip is detected. It is preferable to switch to the total power priority control mode. In this way, when the slip is detected and the required drive torque of the vehicle suddenly decreases, the control mode of the second electric motor is switched to the total power priority control mode to prevent the occurrence of overvoltage as quickly as possible. In addition, the torque of the second electric motor can be controlled to the first target torque corresponding to the required drive torque of the vehicle, and the torque controllability can be improved.

  Further, as in claim 3, when the slip is detected, the generated power of the first motor may be reduced by the generated power reduction control means. In this way, when slip is detected, even if the target torque of the second motor is reduced and the power consumption of the second motor is reduced, the generated power of the first motor is reduced. The change in the total power can be effectively suppressed, and the occurrence of overvoltage can be effectively prevented.

  Alternatively, as described in claim 4, road surface state determining means for determining the state of the traveling road surface of the vehicle is provided, and when the traveling road surface is determined to be in the low friction coefficient state, the generated electric power of the first motor is generated. You may make it reduce with an electric power fall control means. If it does in this way, when it determines with a driving | running | working road surface being a low friction coefficient state, it will estimate that a slip will generate | occur | produce and will reduce the electric power generation of a 1st electric motor beforehand before a slip generate | occur | produces. Can do.

  Incidentally, as shown in FIG. 6, in a situation where wheel slip occurs intermittently (a situation where the wheel slip and the grip are alternately repeated), the rotation speed of the second motor vibrates (increases or decreases). As the torque of the second motor decreases, the power consumption of the second motor may decrease while vibrating. In such a case, as shown in FIG. 6 (a), if the target generated power of the first motor is reduced while being oscillated so as to suppress the change in the total power, the first power is generated by the power of the internal combustion engine. When the responsiveness of the first motor is not so good as in the system for driving the motor, the actual generated power cannot follow the change in the target generated power of the first motor with good response. The change in total power cannot be suppressed, and overvoltage may occur.

  As a countermeasure, it is preferable to maintain the target generated power of the first motor at a predetermined value or lower when the generated power of the first motor is reduced as in the fifth aspect. In this way, even when the power consumption of the second motor decreases while oscillating, such as when a wheel slip occurs intermittently, the target generated power of the first motor is maintained below a predetermined value. Thus, since the actual generated power can be reliably reduced, changes in the total power can be reliably suppressed, and the occurrence of overvoltage can be prevented.

  Further, as in claim 6, in the case where a battery that exchanges electric power with the first electric motor and the second electric motor is provided, the second target torque calculating means is configured to output the electric power of the first electric motor and the second electric motor. The target torque (second target torque) of the second motor may be calculated so that the total power obtained from the power of the second motor does not exceed the maximum allowable charging power and the maximum allowable discharging power of the battery. In this way, it is possible to prevent the total power from exceeding the maximum allowable charging power or the maximum allowable discharging power of the battery, to suppress the battery power transfer amount within an allowable range, and to protect the battery. .

  Further, when the electric load driven by the generated electric power of the first electric motor or the electric power of the battery is provided as in the seventh aspect, the second target torque calculating means is configured to obtain the electric power of the first electric motor. The target torque (second target torque) of the second motor is set so that the total power obtained from the power of the second motor and the power consumption of the electric load does not exceed the maximum allowable charging power and the maximum allowable discharging power of the battery. It may be calculated. In this way, it is possible to prevent the total electric power including the electric load other than the first electric motor and the second electric motor from exceeding the maximum allowable charging power and the maximum allowable discharging power of the battery, and to reduce the amount of battery power exchanged. The battery can be reliably protected within the allowable range, and the battery can be reliably protected.

Hereinafter, an embodiment embodying the best mode for carrying out the present invention will be described.
First, a schematic configuration of a hybrid vehicle drive system will be described with reference to FIG.
The hybrid vehicle includes an engine 11 that is an internal combustion engine, a first motor generator (hereinafter referred to as “first MG”) 12, and a second motor generator (hereinafter referred to as “second MG”) 13. The engine 11 and the second MG 13 are mounted as a power source for driving the wheels 14. The power of the crankshaft 15 of the engine 11 is divided into two systems by a planetary gear mechanism 16 which is a power split mechanism. The planetary gear mechanism 16 includes a sun gear 17 that rotates at the center, a planetary gear 18 that revolves while rotating on the outer periphery of the sun gear 17, and a ring gear 19 that rotates on the outer periphery of the planetary gear 18. The crankshaft 15 of the engine 11 is connected through a non-carrier, the rotating shaft of the second MG 13 and the drive shaft 20 of the wheel 14 are connected to the ring gear 19, and the sun gear 17 is used mainly as a generator. The rotating shaft of 1 MG12 is connected. In this case, the first MG 12 corresponds to the first electric motor referred to in the claims, and the second MG 13 corresponds to the second electric motor referred to in the claims.

  The first MG 12 and the second MG 13 exchange power with the battery 29 via inverters 27 and 28, respectively. A crank angle sensor 31 that outputs a pulse signal every time the crankshaft 15 rotates a predetermined crank angle is attached to the engine 11, and the crank angle and the engine rotation speed are detected based on the output signal of the crank angle sensor 31. Is done. Furthermore, the first MG 12 and the second MG 13 are provided with rotational position sensors 32 and 33 for detecting the rotational position of the rotor, respectively, and the first MG 12 is based on the output signals of these rotational position sensors 32 and 33. And the rotation speed of the second MG 13 are detected.

  The hybrid ECU 30 is a computer that comprehensively controls the entire hybrid vehicle, and includes an accelerator sensor 21 that detects an accelerator opening, a shift switch 22 that detects a shift range of an automatic transmission, a brake switch 23 that detects a brake operation, and the like. The output signals of various sensors and switches are read to detect the driving state of the vehicle and determine the required travel mode. The hybrid ECU 30 includes an engine ECU 24 that controls the operation of the engine 11, a first MG-ECU 25 that controls the operation of the first MG 12, and a second MG-ECU 26 that controls the operation of the second MG 13. Control signals are transmitted and received between the ECUs 24 to 26, and the operations of the engine 11, the first MG 12, and the second MG 13 are controlled according to the required travel mode.

  For example, at the time of starting or low / medium speed travel (region where the fuel efficiency of the engine 11 is poor), the motor travel mode is selected in which the engine 11 is kept stopped and travel is performed only with the power of the second MG 13. In this motor travel mode, the drive shaft 20 is driven only by the power of the second MG 13 to drive the wheels 14. At this time, a part of the rotational force of the second MG 13 is transmitted to the ring gear 19 of the planetary gear mechanism 16, whereby the ring gear 19 rotates, the planetary gear 18 rotates, and the sun gear 17 rotates. The MG 12 is driven to rotate.

  Further, when the engine 11 is started during the motor travel mode, torque is generated in the first MG 12 to act on the sun gear 17 of the planetary gear mechanism 16, thereby causing the planetary gear along the outer periphery of the sun gear 17. By changing the revolution speed of 18, the crankshaft 15 of the engine 11 is rotationally driven to start the engine 11.

  During normal driving, the power of the crankshaft 15 of the engine 11 is driven by the planetary gear mechanism 16 so that the fuel efficiency of the engine 11 is maximized and the drive shaft 20 side (rotation shaft side of the second MG13). ), The drive shaft 20 is driven by the output of one of the systems to drive the wheels 14, the first MG 12 is driven by the output of the other system, and the power generated thereby is supplied to the second system. The wheel 14 is also driven by the power of the second MG 13 supplied to the MG 13.

  At the time of sudden acceleration, the most torque is required. Therefore, in addition to the generated power during normal driving, the direct current power of the battery 29 is added and converted into alternating current power by the inverter 28 and supplied to the second MG 13. The MG 13 is operated. Thus, the acceleration performance is improved by driving the drive shaft 20 with the power of both the engine 11 and the second MG 13 to drive the wheels 14.

  At the time of deceleration or braking, the wheel 14 drives the second MG 13 to act as a generator, converts the deceleration energy and braking energy of the vehicle into electric power, and charges the battery 29.

  Further, the hybrid ECU 30 sets the traction control flag to ON to limit the required drive torque of the vehicle when the slip of the wheel 14 is detected (for example, during the occurrence of the slip and within a predetermined time from the end of the slip). In this case, when the torque of the second MG 13 suddenly decreases and the power consumption of the second MG 13 rapidly decreases, the function of the second MG 13 decreases. The generated power of the first MG 12 becomes excessive with respect to the power consumption of the second MG 13, so that the input voltage of the inverter 28 that drives the second MG 13 rapidly rises and an overvoltage is applied to the inverter 28. There is sex.

  As a countermeasure against such an overvoltage, the hybrid ECU 30 executes the torque control routines of FIGS. 2 to 4 described later, so that in the normal time (non-slip detection), the hybrid ECU 30 performs the second in the torque priority control mode. When the torque of the MG 13 is controlled and the slip of the wheel 14 is detected, the torque of the second MG 13 is controlled by switching to the total power priority control mode.

  In the torque priority control mode, the target torque T1 of the second MG 13 is calculated based on the required drive torque of the vehicle and the target torque of the engine 11, so that the target torque T1 in the torque priority control mode is calculated as the required drive torque of the vehicle. Is set to the first target torque (target torque for realizing the required drive torque of the vehicle), and the torque of the second MG 13 is controlled to be the target torque T1 in the torque priority control mode. The target torque T1 in the torque priority control mode corresponds to the first target torque referred to in the claims.

  On the other hand, in the total power priority control mode, it is driven by the power consumption of the second MG 13, the generated power of the first MG 12, and an electric load (not shown) (for example, the generated power of the first MG 12 to the power of the battery 29). The target torque T2 of the second MG 13 is calculated so that the total power (power balance) summed with the power consumption of the air conditioner etc. is within a predetermined range and the change amount of the total power per predetermined period is less than a predetermined value. Thus, the target torque T2 in the total power priority control mode is set within the range in which the change in the total power can be suppressed and the occurrence of overvoltage can be prevented, and the first target torque (torque priority) corresponding to the required drive torque of the vehicle. It is set so as to approach the target torque T1) in the control mode, and the torque of the second MG 13 is controlled to become the target torque T2 in the total power priority control mode. The target torque T2 in the total power priority control mode corresponds to the second target torque referred to in the claims.

  When calculating the total power (power balance), if the power consumption of the second MG 13 and the electric load is a positive value, the generated power of the first MG 12 is a negative value, and the second MG 13 and the electric load are When the power consumption is negative, the power generated by the first MG 12 may be positive.

  Hereinafter, the processing contents of each routine for torque control shown in FIGS. 2 to 4 executed by the hybrid ECU 30 will be described.

[Torque control main routine]
The torque control main routine shown in FIG. 2 is executed at a predetermined cycle while the hybrid ECU 30 is powered on. When this routine is started, first, in step 101, the target torque T1 of the second MG 13 is calculated based on the required drive torque of the vehicle and the target torque of the engine 11, so that the target torque in the torque priority control mode is calculated. T1 is set to a first target torque corresponding to the required drive torque of the vehicle (target torque for realizing the required drive torque of the vehicle). The process of step 101 serves as a first target torque calculation means in the claims.

  Thereafter, the process proceeds to step 102, and a target torque calculation routine in the total power priority control mode of FIG. 3 to be described later is executed, whereby the power consumption of the second MG 13, the generated power of the first MG 12, and the electric load (for example The target torque in the total power priority control mode of the second MG 13 so that the total power (power balance) calculated from the power consumption of the air conditioner etc. is within a predetermined range and the change amount of the total power is not more than a predetermined value. T2 (second target torque) is calculated.

  Thereafter, the process proceeds to step 103, where it is determined whether the slip is occurring or within a predetermined time from the end of the slip. At this time, as a slip detection method, for example, the slip ratio of the drive wheel 14 is calculated based on the rotation speed of the drive wheel 14 and the rotation speed of a non-drive wheel (not shown), and the slip ratio is a predetermined slip. When the determination value is exceeded, it is determined that slip has occurred. This function serves as slip detection means in the claims. Needless to say, the slip detection method may be changed as appropriate.

  If it is determined in step 103 that a slip is occurring or within a predetermined time from the end of the slip, the process proceeds to step 104 and the control mode of the second MG 13 is switched to the total power priority control mode.

  On the other hand, if it is determined in step 103 that no slip is occurring and it is not within a predetermined time from the end of the slip, the process proceeds to step 105 and the control mode of the second MG 13 is switched to the torque priority control mode. The processing of these steps 104 and 105 serves as a control mode switching means in the claims.

  Thereafter, the process proceeds to step 106, where the second MG-ECU 26 is instructed to control the torque of the second MG in the control mode selected in step 104 or step 105.

[Target torque calculation routine in total power priority control mode]
The target torque calculation routine in the total power priority control mode shown in FIG. 3 is a subroutine executed in step 102 of the torque control main routine of FIG. 2, and as a second target torque calculation means in the claims. To play a role.

  When this routine is started, first, at step 201, the target torque lower limit value Td in the total power priority control mode of the second MG 13 is calculated as follows.

First, the absolute value of the total power obtained by summing the power consumption of the second MG 13, the power generation of the first MG 12 and the power consumption of an electric load (such as an air conditioner) is a predetermined value (for example, the maximum allowable charging power of the battery 29). Pa1) A target torque lower limit value Td1 that is equal to or less than the following is calculated by the following equation.
Td1 = (Pa1-Pb) / Nm
Here, Pb is the sum of the power generated by the first MG 12 and the power consumed by the electric load, and Nm is the rotational speed of the second MG 13.

Further, a target torque lower limit value Td2 at which the absolute value of the change amount of the total power (for example, the difference between the current value and the previous value) is equal to or less than a predetermined value (for example, the maximum allowable charge power change amount ΔPa1 of the battery 29) is calculated by the following equation: To do.
Td2 = (. DELTA.Pa1-.DELTA.Pb + Pm.0) / Nm

  Here, ΔPb is the amount of change in power (for example, the difference between the current value and the previous value) that is the sum of the power generated by the first MG 12 and the power consumed by the electric load, and Pm.0 is the power consumed by the second MG 13. This is the previous value of power.

  The larger of the two target torque lower limit values Td1 and Td2 thus determined is selected as the final target torque lower limit value Td. Thus, the target torque lower limit value Td is set so that the total power does not exceed the maximum allowable charge power of the battery 29 and the change amount of the total power does not exceed the maximum allowable charge power change amount of the battery 29.

  Thereafter, the process proceeds to step 202, and the target torque upper limit Tu in the total power priority control mode of the second MG 13 is calculated as follows.

First, the absolute value of the total power obtained by summing the power consumption of the second MG 13, the power generation of the first MG 12 and the power consumption of an electric load (such as an air conditioner) is a predetermined value (for example, the maximum allowable discharge power of the battery 29). Pa2) A target torque upper limit value Tu1 that is equal to or less than the following is calculated by the following equation.
Tu1 = (Pa2-Pb) / Nm

Further, the target torque upper limit value Tu2 at which the absolute value of the total power change amount (for example, the difference between the current value and the previous value) is equal to or less than a predetermined value (for example, the maximum allowable discharge power change amount ΔPa2 of the battery 29) is calculated by the following equation. To do.
Tu2 = (ΔPa2−ΔPb + Pm.0) / Nm

  The smaller one of the two target torque upper limit values Tu1 and Tu2 thus determined is selected as the final target torque upper limit value Tu. Thus, the target torque upper limit value Tu is set so that the total power does not exceed the maximum allowable discharge power of the battery 29 and the change amount of the total power does not exceed the maximum allowable discharge power change amount of the battery 29.

Thereafter, the process proceeds to step 203, in which it is determined whether or not the target torque T1 (first target torque corresponding to the required drive torque of the vehicle) in the torque priority control mode is smaller than the target torque lower limit value Td. If it is determined that the target torque T1 in the control mode is smaller than the target torque lower limit value Td, the process proceeds to step 205, and the target torque T2 (second target torque) in the total power priority control mode is set as the target torque lower limit. Set to the value Td.
T2 = Td

On the other hand, if it is determined in step 203 that the target torque T1 in the torque priority control mode is greater than or equal to the target torque lower limit value Td, the process proceeds to step 204, where the target torque T1 in the torque priority control mode (vehicle It is determined whether or not the first target torque corresponding to the required drive torque is greater than the target torque upper limit value Tu, and the target torque T1 in the torque priority control mode is determined to be greater than the target torque upper limit value Tu. In this case, the process proceeds to step 206, where the target torque T2 in the total power priority control mode is set to the target torque upper limit value Tu.
T2 = Td

In step 203, it is determined that the target torque T1 in the torque priority control mode is equal to or greater than the target torque lower limit value Td, and in step 204, the target torque T1 in the torque priority control mode is equal to or less than the target torque upper limit value Tu. If it is determined that (Td <T1 <Tu), the routine proceeds to step 207, where the target torque T2 in the total power priority control mode is set to the same value as the target torque T1 in the torque priority control mode.
T2 = T1

  As a result of the above processing, the target torque T2 (second target torque) in the total power priority control mode corresponds to the required drive torque of the vehicle within a range in which the change in the total power can be suppressed and the occurrence of overvoltage can be prevented. It is set so as to approach 1 target torque (target torque T1 in the torque priority control mode).

[Target generated power calculation routine]
The target generated power calculation routine shown in FIG. 4 is executed at a predetermined cycle while the hybrid ECU 30 is powered on. When this routine is started, first, in step 301, the required generated power Pgrq is calculated based on the rotation speed of the second MG 13 and the required drive torque.

  Thereafter, the process proceeds to step 302, where it is determined whether the slip is occurring or within a predetermined time from the end of the slip. If it is determined that the slip is occurring or within the predetermined time from the end of the slip, Proceeding to step 303, it is determined whether or not the current required generated power Pgrq is smaller than the minimum required generated power Pgrq (min) up to the previous time.

If it is determined in this step 303 that the current required generated power Pgrq is smaller than the minimum required generated power Pgrq (min) up to the previous time, the process proceeds to step 304 and the minimum required generated power Pgrq (min ) Is updated with the current required generated power Pgrq.
Pgrq (min) = Pgrq

  On the other hand, if it is determined in step 303 that the current required generated power Pgrq is greater than or equal to the previous minimum required generated power Pgrq (min), the minimum required generated power Pgrq (min) is updated. The process proceeds to step 305 without doing so.

In this step 305, the minimum value Pgrq (min) of the required generated power is set as the final target generated power Pgtag.
Pgtag = Pgrq (min)

  By the processing of these steps 303 to 305, when slip is detected, the target generated power of the first MG 12 is maintained at a predetermined value (minimum value of required generated power) and the generated power of the first MG 12 is reduced. . The processing of these steps 303 to 305 plays a role as the generated power reduction control means in the claims.

On the other hand, if it is determined in the above step 302 that no slip is occurring and it is not within a predetermined time from the end of the slip, the process proceeds to step 306 and the current requested generated power Pgrq is directly used as the final target generated power Pgtag. Set.
Pgtag = Pgrq

  Conventionally, as shown in FIG. 5A, when slip is detected (when the traction control flag is turned on), the torque of the second MG is decreased at a lower rate of change than usual. The second MG torque cannot be quickly reduced to a torque corresponding to the required drive torque of the vehicle, and the drive torque of the vehicle cannot be quickly controlled to the required drive torque.

  On the other hand, in the present embodiment, as shown in FIG. 5B, when the slip is detected (when the traction control flag is turned on), the control mode of the second MG 13 is set to the total power priority control. Switching to the mode, the total power (power balance) obtained by summing the power consumption of the second MG 13, the power generation power of the first MG 12 and the power consumption of the electric load is within a predetermined range, and the change of the total power per predetermined period By calculating the target torque T2 (second target torque) of the second MG 13 so that the amount is equal to or less than the predetermined value, the target torque T2 in the total power priority control mode can be suppressed while suppressing the change in the total power. Within the range in which overvoltage can be prevented, the first target torque (target torque T1 in the torque priority control mode) corresponding to the required drive torque of the vehicle is set. As a result, when slippage is detected and the required drive torque of the vehicle suddenly decreases, the torque of the second MG 13 is changed to the required drive torque of the vehicle as quickly as possible while preventing overvoltage from being applied to the inverter 28. The corresponding torque can be controlled, and the vehicle drive torque can be controlled to the required drive torque as quickly as possible, so that the torque controllability can be improved.

  In addition, in this embodiment, when setting the target torque T2 of the second MG 13 during the total power priority control mode, the power consumption of the second MG 13, the power generation of the first MG 12, and the power consumption of the electric load The target torque T2 (second target torque) of the second MG 13 is set so that the total power obtained by summing up the maximum allowable charging power and maximum allowable discharging power of the battery 29 is not exceeded. It is possible to prevent exceeding the maximum allowable charging power and the maximum allowable discharging power of 29, to suppress the power transfer amount of the battery 29 within the allowable range, and to protect the battery 29.

  In the above embodiment, the total power of the power consumption of the second MG 13, the power generation of the first MG 12 and the power consumption of the electric load does not exceed the maximum allowable charging power and the maximum allowable discharging power of the battery 29. In this way, the target torque T2 of the second MG 13 is set. However, when the influence of the electric load is small, the total power obtained by summing the power consumption of the second MG 13 and the power generated by the first MG 12 is The target torque T2 of the second MG 13 may be set so as not to exceed the maximum allowable charging power and the maximum allowable discharging power of the battery 29.

  Further, in the present embodiment, when the slip is detected, the generated power of the first MG 12 is reduced, so that when the slip is detected, the target torque of the second MG 13 is reduced and the second torque is reduced. Even if the power consumption of the MG 13 is reduced, by reducing the generated power of the first MG 12, the change in the total power can be effectively suppressed, and the occurrence of overvoltage can be effectively prevented.

  Incidentally, as shown in FIG. 6, in a situation where slip occurs intermittently (a situation where slip and grip are alternately repeated), the rotational speed of the second MG 13 vibrates (increases / decreases). As the torque decreases, the power consumption of the second MG 13 may decrease while oscillating. In such a case, as shown in FIG. 6A, if the target generated power of the first MG 12 is reduced while being oscillated so as to suppress the change in the total power, the first power is generated by the power of the engine 11. If the responsiveness of the first MG12 is not so good as in the system driving the MG12, the actual generated power cannot follow the change in the target generated power of the first MG12 with good response. The change in total power cannot be suppressed, and overvoltage may occur.

  As a countermeasure, in this embodiment, as shown in FIG. 6B, when the generated power of the first MG 12 is reduced, the target generated power of the first MG 12 is set to a predetermined value (the minimum value of the required generated power). Therefore, even when the power consumption of the second MG 13 decreases while oscillating as in the case where slip occurs intermittently, the target generated power of the first MG 12 is maintained at a predetermined value. Thus, since the actual generated power can be reliably reduced, changes in the total power can be reliably suppressed, and the occurrence of overvoltage can be prevented.

  In the above-described embodiment, when the generated power of the first MG 12 is reduced, the target generated power of the first MG 12 is maintained at the minimum value of the required generated power. The target generated power of one MG 12 may be maintained at a predetermined value set in advance, or may be limited to a predetermined value or less.

  Further, in the above embodiment, the generated power of the first MG 12 is reduced when slip is detected, but the first MG 12 is determined when it is determined that the traveling road surface of the vehicle is in the low friction coefficient state. The generated power may be reduced. If it does in this way, when it determines with a driving | running | working road surface being a low friction coefficient state, it will estimate that a slip will generate | occur | produce and it reduces the electric power generation of 1st MG12 beforehand before a slip generate | occur | produces. be able to.

  In this case, the method for determining the friction coefficient of the traveling road surface is, for example, calculating the slip ratio of the drive wheel 14 based on the rotation speed of the drive wheel 14 and the rotation speed of the non-drive wheel (not shown), and the first The driving force of the vehicle is calculated based on the target torque of the MG 12 and the target torque of the second MG 13, and the friction coefficient of the traveling road surface is determined based on the driving force and the slip rate. This function plays a role as road surface condition judging means in the claims. The method for determining the friction coefficient of the traveling road surface may be changed as appropriate.

  In the above embodiment, the control mode of the second MG 13 is switched to the total power priority control mode when a slip is detected. However, the present invention is not limited to this, and the vehicle is not limited to when a slip is detected. When the required driving torque changes suddenly, the control mode of the second MG 13 may be switched to the total power priority control mode.

  In addition, the present invention is not limited to the hybrid vehicle of the drive system described in the above embodiment, and includes a first electric motor mainly for power generation and a second electric motor capable of driving wheels with the generated electric power of the electric motor. Needless to say, various modifications can be made without departing from the scope of the invention, for example, the invention can be widely applied to an electric vehicle provided.

1 is a schematic configuration diagram of a hybrid vehicle drive system according to an embodiment of the present invention. It is a flowchart explaining the flow of a process of a torque control main routine. It is a flowchart explaining the flow of the process of the target torque calculation routine at the time of total power priority control mode. It is a flowchart explaining the flow of a process of a target generated electric power calculation routine. (A) is a time chart explaining the conventional torque control, (b) is a time chart explaining the torque control of a present Example. (A) is a time chart explaining the setting method of the target generated electric power of a comparative example, (b) is a time chart explaining the setting method of the target generated electric power of a present Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... 1st MG, 13 ... 2nd MG, 14 ... Wheel, 15 ... Crankshaft, 16 ... Planetary gear mechanism, 24 ... Engine ECU, 25 ... 1st MG-ECU , 26 ... second MG-ECU, 27, 28 ... inverter, 29 ... battery, 30 ... hybrid ECU (first target torque calculating means, second target torque calculating means, control mode switching means, slip detecting means, Generation power reduction control means)

Claims (7)

In a control apparatus for an electric vehicle comprising: a first electric motor mainly for power generation; and a second electric motor capable of driving the wheels of the vehicle with the generated electric power of the first electric motor.
First target torque calculating means for calculating a target torque of the second electric motor (hereinafter referred to as “first target torque”) based on a required driving torque of the vehicle;
The total power obtained from the power generation or power consumption of the first motor and the power consumption or power generation of the second motor is within a predetermined range, and the change amount of the total power per predetermined period is less than a predetermined value. Second target torque calculating means for calculating a target torque of the second electric motor (hereinafter referred to as “second target torque”);
Torque priority control mode for controlling the torque of the second motor to be the first target torque, and total power priority control for controlling the torque of the second motor to be the second target torque And a control mode switching means for switching between the modes. Slip detecting means for detecting slip of the wheel;
Comprising slip suppression control means for limiting the required drive torque when slip is detected by the slip detection means,
The control apparatus for an electric vehicle according to claim 1, wherein the control mode switching means switches to the total power priority control mode when a slip is detected by the slip detection means.   The control apparatus for an electric vehicle according to claim 2, further comprising a generated power reduction control unit that reduces the generated power of the first electric motor when a slip is detected by the slip detection unit. Comprising road surface state determining means for determining the state of the road surface of the vehicle,
The apparatus according to claim 2, further comprising a generated power reduction control unit that reduces the generated power of the first electric motor when the road surface state determining unit determines that the traveling road surface is in a low friction coefficient state. The control apparatus of the electric vehicle as described.   The control device for an electric vehicle according to claim 3 or 4, wherein the generated power reduction control means maintains the target generated power of the first electric motor at a predetermined value or less. A battery for transferring power to and from the first motor and the second motor;
The second target torque calculation means is configured such that the total power obtained from the power generation or power consumption of the first motor and the power consumption or power generation of the second motor is a maximum allowable charge power and a maximum allowable discharge power of the battery. The control device for an electric vehicle according to claim 1, wherein the second target torque is calculated so as not to exceed the threshold. An electric load driven by the generated electric power of the first electric motor or the electric power of the battery;
The second target torque calculating means is configured such that the total power obtained from the power generation or power consumption of the first motor, the power consumption or power generation of the second motor, and the power consumption of the electric load is a maximum allowable power of the battery. The control apparatus for an electric vehicle according to claim 6, wherein the second target torque is calculated so as not to exceed charging power and maximum allowable discharge power.

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