JP2010136509A - Vehicle and its controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve energy efficiency of a vehicle and to appropriately charge an auxiliary machine power storage means much more. <P>SOLUTION: In power running when a motor MG2 outputs travel torque, prescribed voltage VL is set in target output voltage V* as a target value of output voltage to a low voltage power line 94 of a DC/DC converter 92. In power regeneration of the motor MG2, voltage VH higher than voltage VL is set in target output voltage V* of the DC/DC converter 92. The DC/DC converter 92 is controlled so that auxiliary machine battery voltage Vb from a voltage sensor 98 becomes target output voltage V*. Thus, energy efficiency of a hybrid vehicle 20 is improved and an auxiliary machine battery 90 is appropriately charged much more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle and a control method thereof.

Conventionally, this type of vehicle is connected to a first motor generator coupled to an engine, a second motor generator coupled to drive wheels, and a first motor generator and a second motor generator via a boost converter. Main power storage device, auxiliary power storage device that supplies power to the vehicle ECU and auxiliary equipment, and the DC voltage from the main power storage device side is converted to the voltage level of the auxiliary power storage device and output to the auxiliary power storage device A bidirectional DC / DC converter is proposed (see, for example, Patent Document 1). In this vehicle, when the temperature of the outside air is lower than the threshold temperature when the ignition key is turned to the OFF position, it is determined that a voltage drop of the auxiliary power storage device may occur at the next vehicle system startup. And in order to raise the electrical storage amount (SOC) of the auxiliary power storage device, the first motor generator generates electric power using the engine power to charge the auxiliary power storage device.
JP 2007-252072 A

  However, if the engine is operated after the ignition key is turned off as in the conventional vehicle to enable power generation by the first motor generator, the power storage device for auxiliary machines is charged with the power generated by the first motor generator. Although it is possible to operate the engine despite the ignition key being turned off, the fuel efficiency, that is, the energy efficiency of the vehicle is deteriorated.

  The vehicle of the present invention is mainly intended to improve the energy efficiency of the vehicle and more appropriately charge the auxiliary power storage means.

  The vehicle and the control method thereof according to the present invention employ the following means in order to achieve the main object described above.

The vehicle of the present invention
An electric motor capable of outputting driving power to a drive shaft connected to the drive wheel and capable of outputting braking force to the drive shaft by regenerating electric power;
A running power storage means connected to the motor via a high voltage power line and capable of exchanging power with the motor;
Auxiliary power storage means connected to the auxiliary machine via a low-voltage power line and capable of supplying power to the auxiliary machine,
Voltage conversion means connected to the high-voltage power line and the low-voltage power line, capable of converting the voltage from the high-voltage power line side and outputting the voltage to the low-voltage power line side;
At the time of power running when the electric motor outputs driving power, the first voltage is set as a target voltage that is a target value of the output voltage of the voltage conversion means, and at the time of power regeneration that the motor outputs braking force, Target voltage setting means for setting a second voltage higher than the first voltage as the target voltage;
Control means for controlling the voltage conversion means so that the output voltage of the voltage conversion means becomes the set target voltage;
It is a summary to provide.

  In the vehicle of the present invention, when the electric power is output when the electric motor outputs the driving power, the first voltage is set to the target voltage that is the target value of the output voltage of the voltage conversion means, and the electric power at which the electric motor outputs the braking force. During regeneration, the second voltage higher than the first voltage is set as the target voltage, and the voltage conversion means is controlled so that the output voltage of the voltage conversion means becomes the set target voltage. As a result, during power regeneration, more power than that during powering is converted by the voltage conversion means and supplied from the high-voltage power line side to the low-voltage power line side to drive the auxiliary equipment and charge the auxiliary power storage means. In particular, when the amount of power regenerated by the electric motor is large, the auxiliary power storage means can be charged by effectively using surplus power that could not be absorbed by the travel power storage means. . Further, during power running, by reducing the target voltage of the voltage conversion means, it is possible to suppress the use of electric power from the high-voltage power line side for driving the auxiliary equipment or charging the auxiliary power storage means. As a result, it is possible to reduce the amount of power taken from the power source to the low-voltage power line side to suppress a decrease in the remaining capacity of the power storage means for travel, and to reduce power consumption in the auxiliary equipment. Therefore, according to this vehicle, the energy efficiency can be improved and the auxiliary power storage means can be more appropriately charged.

  The vehicle according to the present invention further includes voltage detection means for detecting the voltage of the auxiliary power storage means, and the target voltage setting means applies a voltage lower than the voltage detected by the voltage detection means to the first voltage. While setting to a voltage, it can also be a means to set a voltage higher than the voltage detected by the voltage detection means to the second voltage. By so doing, it is possible to more appropriately charge and discharge the auxiliary power storage means and improve the energy efficiency of the vehicle.

  In the vehicle of the present invention, an internal combustion engine capable of outputting power, a generator connected to the high-voltage power line and capable of exchanging power with the power storage means and capable of inputting / outputting power, and the drive shaft Three shafts connected to three shafts of the output shaft of the internal combustion engine and the rotating shaft of the generator, and for inputting / outputting power to / from the remaining shafts based on power input / output to / from any two of these three shafts And a power input / output unit.

The vehicle control method of the present invention includes:
An electric motor capable of outputting driving power to a drive shaft connected to the drive wheels and capable of outputting braking force to the drive shaft by regenerating electric power, and connected to the electric motor via a high-voltage power line Power storage means for traveling that can exchange power with the motor, power storage means for auxiliary equipment that is connected to an auxiliary machine via a low-voltage power line and can supply power to the auxiliary machine, the high-voltage power line, and the low-voltage power A voltage conversion means that is connected to a line and is capable of converting the voltage from the high-voltage power line side and outputting the voltage to the low-voltage power line side, and a vehicle control method comprising:
At the time of power running when the electric motor outputs driving power, the first voltage is set as a target voltage that is a target value of the output voltage of the voltage conversion means, and at the time of power regeneration that the motor outputs braking force, Setting a second voltage higher than the first voltage as the target voltage, and controlling the voltage conversion means so that the output voltage of the voltage conversion means becomes the set target voltage;
This is the gist.

  In the vehicle control method of the present invention, when the electric power is output when the electric motor outputs driving power, the first voltage is set to the target voltage that is the target value of the output voltage of the voltage conversion means, and the electric motor applies the braking force. During power regeneration, the second voltage higher than the first voltage is set as the target voltage, and the voltage conversion means is controlled so that the output voltage of the voltage conversion means becomes the set target voltage. As a result, during power regeneration, more power than that during powering is converted by the voltage conversion means and supplied from the high-voltage power line side to the low-voltage power line side to drive the auxiliary equipment and charge the auxiliary power storage means. In particular, when the amount of power regenerated by the electric motor is large, the auxiliary power storage means can be charged by effectively using surplus power that could not be absorbed by the travel power storage means. . Further, during power running, by reducing the target voltage of the voltage conversion means, it is possible to suppress the use of electric power from the high-voltage power line side for driving the auxiliary equipment or charging the auxiliary power storage means. As a result, it is possible to reduce the amount of power taken from the power source to the low-voltage power line side to suppress a decrease in the remaining capacity of the power storage means for travel, and to reduce power consumption in the auxiliary equipment. Therefore, according to this vehicle control method, the energy efficiency can be improved and the auxiliary power storage means can be more appropriately charged.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as a vehicle according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. Motor MG1 capable of generating power connected to mechanism 30, motor MG2 connected to ring gear shaft 32a as a drive shaft connected to power distribution and integration mechanism 30 via reduction gear 35, inverters 41 and 42, and high-voltage power Main battery 50 that exchanges power with motors MG1 and MG2 through line 54, auxiliary battery 90 that can supply power to auxiliary machine 96 through low-voltage power line 94, high-voltage power line 54, and low-voltage power DC / D connected to the line 94 to step down the power from the high voltage power line 54 side and output it to the low voltage power line 94 side It includes a converter 92, and a hybrid electronic control unit 70 that controls the entire hybrid vehicle 20.

  The engine 22 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil. The engine electronic control unit (hereinafter referred to as engine ECU) 24 performs fuel injection control, ignition control, and intake air amount adjustment. Under control of operation such as control. The engine ECU 24 receives signals from various sensors that detect the operating state of the engine 22, for example, a crank position from a crank position sensor (not shown) that detects the crank angle of the crankshaft 26 of the engine 22. The engine ECU 24 is in communication with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70.

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via the ring gear shaft 32a. When functioning as a generator, power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the drive wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  Both motor MG1 and motor MG2 are configured as well-known synchronous generator motors that can be driven as generators and can be driven as motors, and exchange power with main battery 50 via inverters 41 and 42. The high-voltage power line 54 that connects the inverters 41 and 42 and the main battery 50 is configured as a positive and negative bus shared by the inverters 41 and 42, and generates electric power generated by either the motor MG 1 or MG 2. It can be consumed by other motors. Therefore, main battery 50 is charged / discharged by electric power generated from one of motors MG1 and MG2 or insufficient electric power. If the balance of electric power is balanced by the motors MG1 and MG2, the main battery 50 is not charged / discharged. The motors MG1 and MG2 are both driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 detects signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and current sensors (not shown). The phase current applied to the motors MG1 and MG2 to be applied is input, and a switching control signal to the inverters 41 and 42 is output from the motor ECU 40. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70.

  In the embodiment, the main battery 50 is configured as a nickel hydride secondary battery or a lithium ion secondary battery having a rated output voltage of 200 to 300 V, and is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. ing. The battery ECU 52 has a signal necessary for managing the main battery 50, for example, a voltage between terminals from a voltage sensor (not shown) installed between terminals of the main battery 50, and an illustration connected to the output terminal of the main battery 50. The charging / discharging current from the current sensor that is not performed, the battery temperature Tb from the temperature sensor 51 attached to the main battery 50, and the like are input. Further, the battery ECU 52 outputs data relating to the state of the main battery 50 to the hybrid electronic control unit 70 by communication as necessary.

  In the embodiment, the auxiliary battery 90 is configured as a lead storage battery having a rated output voltage of 12 V, and is connected to the auxiliary machine 96 via the low-voltage power line 94. The auxiliary machine 96 connected to the low-voltage power line 94 includes a plurality of power devices such as a headlight, a room lamp, and a car audio. The auxiliary battery 90 is also connected to the engine ECU 24, the motor ECU 40, the battery ECU 52, the hybrid electronic control unit 70, and the like via a power line (not shown), and supplies power to these electronic control units.

  Each of the DC / DC converters 92 includes a switching element, a transformer, and the like (not shown). By turning on and off the switching elements, the DC / DC converter 92 can step down the power from the high voltage power line 54 and output it to the low voltage power line 94. The DC / DC converter 92 is controlled by a control signal from the hybrid electronic control unit 70.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. From the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the voltage sensor 98 for detecting the voltage across the auxiliary battery 90. Auxiliary battery voltage Vb and the like are input through the input port. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. Or a control signal for controlling the DC / DC converter 92 is output.

  In the hybrid vehicle 20 of the embodiment thus configured, when the accelerator pedal 83 is depressed by the driver, a drive control routine (not shown) is executed by the hybrid electronic control unit 70, and the accelerator opening corresponding to the depression amount of the accelerator pedal 83 is performed. Based on the degree Acc and the vehicle speed V, the required torque to be output to the ring gear shaft 32a as the drive shaft is calculated, and the required power corresponding to this required torque is output to the ring gear shaft 32a. The point and torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are set. The engine 22 is controlled to operate at the target operating point, and the motors MG1, MG2 are controlled to be driven by torque commands Tm1 *, Tm2 *. Thus, when accelerator pedal 83 is depressed by the driver, torque command Tm2 * is set to a positive value so that motor MG2 outputs a traveling torque (positive torque). On the other hand, when the brake pedal 85 is depressed by the driver, a braking control routine (not shown) is executed by the hybrid electronic control unit 70, and the pedal depression force applied to the brake pedal 85 is calculated based on the depression amount of the brake pedal 85. Based on this pedal depression force, a required braking force to be applied to the vehicle is set, and a required braking torque to be output to the ring gear shaft 32a as a share of the required braking force for the motor MG2 and the engine 22 is calculated. The target rotational speed of the engine 22 and torque commands Tm1 *, Tm2 * of the motors MG1, MG2 are set by the hybrid electronic control unit 70 so that torque corresponding to the required braking torque is output to the ring gear shaft 32a. At this time, the torque command Tm1 * is a positive value so that the engine 22 is motor cut so that the engine 22 is rotated at the target rotational speed by the motor MG1 and the friction torque is output from the engine 22 to the ring gear shaft 32a. The torque command Tm2 * is set to a negative value so that the regenerative braking torque is output to the ring gear shaft 32a by the power regeneration of the motor MG2. Then, the engine 22 is fuel cut and the motors MG1, MG2 are driven and controlled by torque commands Tm1 *, Tm2 *. Thus, when the brake pedal 85 is depressed by the driver, the torque command Tm2 * is set to a negative value so that the motor MG2 outputs the braking torque (negative torque). The operation control mode of the engine 22, the motor MG1, and the motor MG2 controls the operation of the engine 22 so that the power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is distributed. Necessary for torque conversion operation mode for driving and controlling motor MG1 and motor MG2 so that torque is converted by integrated mechanism 30, motor MG1 and motor MG2 and output to ring gear shaft 32a, and required power and charging / discharging of main battery 50 The engine 22 is operated and controlled so that power corresponding to the sum of the electric power is output from the engine 22, and all or part of the power output from the engine 22 with charging / discharging of the main battery 50 is a power distribution and integration mechanism. 30 with torque conversion by motor MG1 and motor MG2 A charge / discharge operation mode for driving and controlling the motor MG1 and the motor MG2 so that the electromotive force is output to the ring gear shaft 32a, and the operation of the engine 22 is stopped so that the power corresponding to the required power from the motor MG2 is output to the ring gear shaft 32a. There are motor operation modes for operation control.

  Next, the operation of the DC / DC converter 92 mounted on the hybrid vehicle 20 of the embodiment thus configured will be described. FIG. 2 is a flowchart showing an example of a DC / DC converter control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed every predetermined time (for example, every several msec).

  When the DC / DC converter control routine is executed, the CPU 72 of the hybrid electronic control unit 70 first inputs data necessary for control, such as the torque command Tm2 * and the auxiliary battery voltage Vb from the voltage sensor 98 ( Step S100). Here, the torque command Tm2 * is input as separately set by the hybrid electronic control unit 70.

  When the data is input in this way, it is checked whether or not the torque command Tm2 * is smaller than the value 0 (step S110). Then, a predetermined voltage VL is set to the target output voltage V * as the target value of the output voltage of the DC / DC converter 92 (step S120). On the other hand, when torque command Tm2 * is less than 0, that is, during power regeneration of motor MG2, voltage VH higher than voltage VL is set as target output voltage V * of DC / DC converter 92 (step S130). Here, voltage VL and voltage VH set as target output voltage V * of the DC / DC converter are set in consideration of the charging characteristics of auxiliary battery 90. In the embodiment, the voltage VL is slightly larger than the rated output voltage of the auxiliary battery 90 so as not to affect the operation of the auxiliary machine 96 and the like due to a significant decrease in the amount of electricity stored in the auxiliary battery 90. 5V or the like is used. As the voltage VH, 14 V which is smaller than the maximum voltage allowed for the auxiliary battery 90 and larger than the voltage VL is used.

  When the target output voltage V * is set in this way, PI control based on the deviation between the set target output voltage V * and the input auxiliary battery voltage Vb so that the auxiliary battery voltage Vb becomes the target output voltage V * (proportional The duty ratio D for switching control of the DC / DC converter 92 is set by integration control) (step S140), and the DC / DC converter 92 is switched based on the set duty ratio D (step S150). This routine ends. By such control, during power regeneration of the motor MG2, more power is stepped down by the DC / DC converter 92 than when powering when the motor MG2 outputs running torque, and the auxiliary machine 96 is driven and the auxiliary battery 90 is driven. In particular, when the amount of power regenerated by the motor MG2 is large, it is possible to charge the auxiliary battery 90 by effectively using the surplus power that could not be absorbed by the main battery 50. . Further, when the motor MG2 is powered, the target output voltage V * of the DC / DC converter 92 is made smaller than that during power regeneration on the assumption that the power stored in the auxiliary battery 90 is used to some extent, so that the high voltage power The power from the line 54 side is restrained from being used for driving the auxiliary machine 96 and charging the auxiliary battery 90, reducing the carry-out of power from the main battery 50 to the low voltage power line 94 side, and remaining the main battery 50. A decrease in capacity (SOC) can be suppressed. If the auxiliary machine 96 is regarded as a simple resistor, the power consumption of the auxiliary machine 96 is proportional to the square of the voltage applied to the auxiliary machine 96. Therefore, by reducing the target output voltage V *, the auxiliary machine 96 The power consumption at 96 can also be reduced. Therefore, according to the hybrid vehicle 20, energy efficiency (fuel consumption) can be improved and the auxiliary battery 90 can be more appropriately charged.

  In the hybrid vehicle 20 according to the embodiment described above, when the motor MG2 outputs a running torque, a predetermined voltage VL is set as the target output voltage V * of the DC / DC converter 92 and the power regeneration of the motor MG2 is performed. Sometimes, the target output voltage V * of the DC / DC converter 92 is set to a voltage VH higher than the voltage VL, and the DC / DC converter 92 is controlled so that the auxiliary battery voltage Vb becomes the target output voltage V *. As a result, during the power regeneration of the motor MG2, more power can be stepped down by the DC / DC converter 92 and used for driving the auxiliary machine 96 and charging the auxiliary battery 90, compared to during power running. When the amount of electric power regenerated by motor MG2 is large, it is possible to charge auxiliary battery 90 by effectively using surplus power that could not be absorbed by main battery 50. Further, when the motor MG2 is powered, the target output voltage V * of the DC / DC converter 92 is reduced so that the power from the high voltage power line 54 side is used for driving the auxiliary machine 96 and charging the auxiliary battery 90. , And the reduction of the remaining capacity (SOC) of the main battery 50 can be suppressed, and the power consumption in the auxiliary device 96 can be reduced. . Therefore, according to hybrid vehicle 20, energy efficiency can be improved and auxiliary battery 90 can be more appropriately charged.

  In the hybrid vehicle 20 of the embodiment, when the DC / DC converter control routine of FIG. 2 is executed by the hybrid electronic control unit 70 and the torque command Tm2 * is greater than or equal to 0, the target output voltage V of the DC / DC converter 92 is A predetermined voltage VL is set to * (step S120), and when the torque command Tm2 * is less than 0, the target output voltage V * is set to a voltage VH higher than the voltage VL (step S130). As in the example of the DC / DC converter control routine of the modification shown in FIG. 3, when the torque command Tm2 * is greater than or equal to 0, the target output voltage V * of the DC / DC converter 92 is more predetermined than the auxiliary battery voltage Vb. Is set to a voltage that is smaller by a voltage α (for example, 0.5 V) (step S125), and the torque command Tm2 * is not 0. When the sets voltage α only voltage greater than the target output voltage V * to Hoki battery voltage Vb may be (step S135) ones. In this way, the auxiliary machine 96 is driven mainly by the electric power stored in the auxiliary battery 90 during the power running of the motor MG2, and the auxiliary machine 96 is driven by the electric power from the DC / DC converter 92 during the electric power regeneration of the motor MG2. Since the auxiliary battery 90 can be charged while being driven, the auxiliary battery 90 can be more appropriately charged and discharged, and the energy efficiency of the hybrid vehicle 20 can be improved. The DC / DC converter control routine of FIG. 3 is the same as the DC / DC converter control routine of FIG. 2 except that the processes of steps S120 and S130 of FIG. 2 are replaced with the processes of steps S125 and S135.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is decelerated by the reduction gear 35 and output to the ring gear shaft 32a. However, like the hybrid vehicle 120 of the modified example illustrated in FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 4) different from an axle to which the ring gear shaft 32a is connected (an axle to which the drive wheels 63a and 63b are connected).

  Further, the vehicle according to the present invention includes a motor MG that is a synchronous generator motor connected to the drive shaft 37, an inverter 43, and a high-voltage power line 54, as in the electric vehicle 220 of the modified example illustrated in FIG. 5. The main battery 50 that exchanges power with the MG, the auxiliary battery 90 that can supply power to the auxiliary machine 96 via the low-voltage power line 94, the high-voltage power line 54, and the low-voltage power line 94 are connected to the high-voltage power. It is good also as a form of an electric vehicle provided with the DC / DC converter 92 which pressure | voltage-falls the electric power from the line 54 side and can output to the low voltage | pressure electric power line 94 side.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor MG2 corresponds to the “motor”, the main battery 50 corresponds to the “driving power storage means”, the auxiliary battery 90 corresponds to the “auxiliary power storage means”, and the DC / DC converter 92 When the torque command Tm2 * is equal to or greater than 0, corresponding to the “voltage converting means”, a predetermined voltage VL is set to the target output voltage V * as the target value of the output voltage of the DC / DC converter 92, and the torque command Tm2 When * is less than 0, the process of steps S110 to S130 of the DC / DC converter control routine of FIG. 2 for setting the target output voltage V * of the DC / DC converter 92 to a voltage VH higher than the voltage VL or the step of FIG. The hybrid electronic control unit 70 that executes the processes of S110, S125, and S135 corresponds to the “target voltage setting means”, and the battery voltage Vb Duty when switching control of the DC / DC converter 92 is performed by PI control (proportional integral control) based on a deviation between the set target output voltage V * and the input auxiliary battery voltage Vb so that the target output voltage V * is obtained. The hybrid electronic control unit 70 that executes the processing of steps S140 to S150 of the DC / DC converter control routine of FIG. 2 that sets the ratio D and controls the switching of the DC / DC converter 92 based on the duty ratio D is “controlled”. It corresponds to “means”.

  Here, the “motor” is not limited to the motor MG2 configured as a synchronous generator motor, but can output power for traveling to a drive shaft connected to an axle, such as an induction motor, and supply electric power. Any type of electric motor may be used as long as it can output a braking force to the drive shaft by regeneration. The “traveling power storage means” is not limited to the main battery 50 configured as a nickel-metal hydride secondary battery having a rated output voltage of 200 to 300 V, but is connected to an electric motor via a high-voltage power line such as a capacitor. Any device can be used as long as it can exchange electric power with the electric motor. The “auxiliary power storage means” is not limited to the auxiliary battery 90 configured as a lead storage battery having a rated output voltage of 12 V, but a low voltage power line such as a nickel metal hydride secondary battery or a lithium ion secondary battery. Any device can be used as long as it can be connected to the auxiliary device via the power supply and can supply power to the auxiliary device. The “voltage converting means” is not limited to the DC / DC converter 92 that can step down the power from the high voltage power line 54 by turning on and off the switching element and output it to the low voltage power line 94. As long as it is connected to the line and the low-voltage power line and can convert the power from the high-voltage power line side and output it to the low-voltage power line side, it may be anything. As the “target voltage setting means”, when the torque command Tm2 * is greater than or equal to 0, a predetermined voltage VL is set to the target output voltage V * as the target value of the output voltage of the DC / DC converter 92, and the torque command Tm2 When * is less than 0, the target output voltage V * of the DC / DC converter 92 is not limited to setting the voltage VH higher than the voltage VL, and at the time of power running in which the motor outputs driving power, A first voltage is set as a target voltage, which is a target value of the output voltage of the voltage conversion means, and a second voltage higher than the first voltage is set as the target voltage during power regeneration when the motor outputs braking force. It does not matter as long as it does. As the “control means”, DC control is performed by PI control (proportional integral control) based on a deviation between the set target output voltage V * and the input auxiliary battery voltage Vb so that the battery voltage Vb becomes the target output voltage V *. The duty ratio D for switching the DC / DC converter 92 is set, and the DC / DC converter 92 is not limited to the switching control based on the duty ratio D, but the output voltage of the voltage conversion means is set. Any device can be used as long as it controls the voltage conversion means so as to obtain the target voltage.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the vehicle manufacturing industry.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as a vehicle according to an embodiment of the present invention. 3 is a flowchart showing an example of a DC / DC converter control routine executed by a hybrid electronic control unit 70; It is a flowchart which shows an example of the DC / DC converter control routine of a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. It is a block diagram which shows the outline of a structure of the electric vehicle 220 of a modification.

Explanation of symbols

  20, 120 Hybrid vehicle, 22 engine, 24 electronic control unit (engine ECU) for engine, 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 carrier, 35 Reduction gear, 37 Drive shaft, 40 Motor electronic control unit (motor ECU), 41, 42, 43 Inverter, 50 Main battery, 51 Temperature sensor, 52 Battery electronic control unit (battery ECU), 54 High voltage power line, 60 Gear mechanism, 62 differential gear, 63a, 63b drive wheel, 64a, 64b wheel, 70 hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 ignition switch, 81 s Ft lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 90 auxiliary battery, 92 DC / DC converter, 94 low voltage power line, 96 auxiliary machine 98, voltage sensor, 220 electric vehicle, MG, MG1, MG2 motor.

Claims (4)

An electric motor capable of outputting driving power to a drive shaft connected to the drive wheel and capable of outputting braking force to the drive shaft by regenerating electric power;
A running power storage means connected to the motor via a high voltage power line and capable of exchanging power with the motor;
Auxiliary power storage means connected to the auxiliary machine via a low-voltage power line and capable of supplying power to the auxiliary machine,
Voltage conversion means connected to the high-voltage power line and the low-voltage power line, capable of converting the voltage from the high-voltage power line side and outputting the voltage to the low-voltage power line side;
At the time of power running when the electric motor outputs driving power, the first voltage is set as a target voltage that is a target value of the output voltage of the voltage conversion means, and at the time of power regeneration that the motor outputs braking force, Target voltage setting means for setting a second voltage higher than the first voltage as the target voltage;
Control means for controlling the voltage conversion means so that the output voltage of the voltage conversion means becomes the set target voltage;
A vehicle comprising: The vehicle according to claim 1,
A voltage detection means for detecting a voltage of the auxiliary power storage means;
The target voltage setting means sets a voltage lower than the voltage detected by the voltage detection means to the first voltage, and sets a voltage higher than the voltage detected by the voltage detection means to the second voltage. Is a means to set
vehicle. The vehicle according to claim 1 or 2,
An internal combustion engine capable of outputting power;
A generator connected to the high-voltage power line and capable of exchanging power with the power storage means and capable of inputting and outputting power;
Connected to the three shafts of the drive shaft, the output shaft of the internal combustion engine, and the rotating shaft of the generator, the power based on the power input / output to / from any two of these three shafts is input to the remaining shaft 3-axis power input / output means for outputting;
A vehicle further comprising: An electric motor capable of outputting driving power to a drive shaft connected to the drive wheels and capable of outputting braking force to the drive shaft by regenerating electric power, and connected to the electric motor via a high-voltage power line Power storage means for traveling that can exchange power with the motor, power storage means for auxiliary equipment that is connected to an auxiliary machine via a low-voltage power line and can supply power to the auxiliary machine, the high-voltage power line, and the low-voltage power A voltage conversion means connected to a line and capable of converting voltage from the high-voltage power line side and outputting the voltage to the low-voltage power line side, and a vehicle control method comprising:
At the time of power running when the electric motor outputs driving power, the first voltage is set as a target voltage that is a target value of the output voltage of the voltage conversion means, and at the time of power regeneration that the motor outputs braking force, Setting a second voltage higher than the first voltage as the target voltage, and controlling the voltage conversion means so that the output voltage of the voltage conversion means becomes the set target voltage;
Control method.

Images