JP2009196415A - Control device and control method for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device and a control method of a hybrid vehicle capable of improving fuel consumption by preventing the overheating of a motor, and without deteriorating the traveling performance of a vehicle. <P>SOLUTION: When a fuel consumption priority mode is selected, a hybrid ECU 15 sets the upper limit value of a motor operation voltage Vm to a voltage which is lower than the motor operation voltage upper limit value during the execution of a normal traveling mode. When the motor temperature of a motor generator MG2 exceeds a prescribed reference temperature during the execution of a fuel consumption priority mode, the hybrid ECU 15 corrects the torque command value of the motor generator MG2 to be lower than a torque command value calculated on the basis of various sensor outputs 17, and compensates the decrease in the torque command value with direct transmission torque to be mechanically directly transmitted from an engine through a power dividing mechanism PSD to a driving shaft. Thus, the insufficiency of a driving force is prevented as a whole vehicle while preventing the overheating of the motor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device and a control method for a hybrid vehicle, and more particularly to a control device and a control method for a hybrid vehicle equipped with a power supply device that drives and controls a motor with level conversion of an input DC voltage.

  Recently, as an environment-friendly vehicle, a hybrid vehicle incorporating a motor (motor) in a drive device has attracted a great deal of attention and has been partially put into practical use. A hybrid vehicle is a vehicle that uses a motor driven by a DC power source via an inverter in addition to a conventional engine as a power source. That is, a power source is obtained by driving the engine, and a DC voltage from a DC power source is converted into an AC voltage by an inverter, and a motor is rotated by the converted AC voltage to obtain a power source.

  In such a hybrid vehicle and an electric vehicle, in order to drive the motor with high efficiency, an applied voltage for driving the motor is provided by providing a level conversion function of the DC voltage input to the power supply device that controls the drive of the motor. (Hereinafter, also referred to as “motor operating voltage”) is being studied for a configuration that can be adjusted according to the motor operating state (rotation speed, torque, etc.). In particular, by providing a step-up function and making the motor operating voltage higher than the input DC voltage, the efficiency of the motor can be increased by reducing the size of the battery as a DC power supply and reducing the power loss associated with higher voltage. It becomes possible.

  For example, Japanese Patent Laying-Open No. 2007-159214 (Patent Document 1) discloses an electric vehicle having a boost converter that boosts the power supply voltage of a traveling motor.

  According to this, the boost converter is configured by a chopper circuit including two switching elements and a reactor connected in series between a power supply line and an earth line of the inverter. The control device performs step-up control for stepping up the voltage of the DC power supply in accordance with the rotational speed of the traveling motor and the target torque. Specifically, the control device boosts the output voltage of the DC power supply and supplies it to the inverter by turning off the switching element of the upper arm of the boost converter and switching the switching element of the lower arm. In this way, the output of the traveling motor can be increased.

On the other hand, when the low fuel consumption travel instruction is received from the user, the control device stops the boost operation by the boost converter. Thereby, after the low fuel consumption travel instruction is input from the user, the switching loss in the boost converter is eliminated, so that the fuel consumption can be improved.
JP 2007-159214 A JP 2007-89262 A JP 2006-321466 A JP 2004-52851 A

  However, in the electric vehicle described in Patent Document 1, after the low fuel consumption travel instruction is input from the user, the voltage of the DC power source is directly applied to the inverter as the motor operating voltage. Therefore, compared to before the low fuel consumption travel instruction is input, the current flowing through each phase coil of the travel motor is increased to output the required torque by the amount that the motor operating voltage is limited.

  As a result, the motor for the traveling motor has a relatively high motor temperature due to an increase in the amount of heat generated, so if the load suddenly fluctuates due to a rapid acceleration / deceleration operation by the driver, the amount of heat generation becomes further excessive. There is a possibility that the traveling motor is overheated. As a result, the output torque of the traveling motor decreases, and the traveling performance of the vehicle decreases.

  Therefore, the present invention has been made in order to solve such a problem, and an object of the present invention is to prevent a motor from being overheated and to improve a fuel consumption without deteriorating the running performance of the vehicle. A vehicle control device and a control method are provided.

  A hybrid vehicle control device according to an aspect of the present invention is a hybrid vehicle control device that outputs power to a drive shaft as an internal combustion engine, a motor, and a power source. The hybrid vehicle has a power source, a converter that boosts and outputs a DC voltage from the power source to a voltage according to a voltage command value, and a motor drive circuit that converts the output voltage of the converter into a motor drive voltage according to a drive force command value Including. The control device determines a sharing ratio of the driving force generated by the internal combustion engine and the motor so that the required driving force of the vehicle is output to the driving shaft, and sets the driving force command value according to the determined sharing ratio. A first motor that sets a voltage command value according to the driving force command value with the first voltage as an upper limit value and controls a current flowing through the motor based on the driving force command value and the output voltage of the converter; The control means sets a voltage command value according to the driving force command value with the second voltage lower than the first voltage as an upper limit value, and sets the voltage command value to the motor based on the driving force command value and the output voltage of the voltage converter. Second motor control means for controlling the flowing current and selection means for selectively executing the first and second motor control means according to the driving state of the vehicle. When the motor temperature exceeds a predetermined reference temperature during the execution of the motor temperature acquisition means for acquiring the motor temperature and the second motor control means, the sharing ratio control means is a driving force generated by the motor. And a sharing ratio changing means for changing the determined sharing ratio.

  Preferably, the sharing ratio changing unit has in advance a ratio of the second voltage to the first voltage as a predetermined correction coefficient, and corrects the driving force command value by multiplying the driving force command value by the predetermined correction coefficient. Correction means.

  Preferably, the hybrid vehicle mechanically couples an input shaft that receives power from the internal combustion engine, a rotation shaft of the motor, and a drive shaft, and mechanically distributes the power from the internal combustion engine to the motor and the drive shaft. It further includes a configured power split mechanism. The sharing ratio changing means is a required driving force based on a driving force generated by the motor in accordance with the corrected driving force command value and a direct driving force that is a driving force transmitted from the internal combustion engine to the driving shaft through the power split mechanism. And a sharing ratio change time control means for controlling the internal combustion engine so that the driving force based on the above acts on the drive shaft.

  Preferably, the sharing ratio change time control means increases the direct drive force with the change of the operation point of the internal combustion engine.

  Preferably, the sharing ratio changing unit is configured to change the voltage when the sum of the direct drive force acting on the drive shaft and the drive force generated by the motor is less than the required drive force during the execution of the second motor control unit. The upper limit value of the command value is changed to the first voltage.

  According to another aspect of the present invention, there is provided a control method for a hybrid vehicle that outputs power to a drive shaft as an internal combustion engine, a motor, and a power source, wherein the hybrid vehicle uses a power supply and a direct current voltage from the power supply as a voltage command value. A converter that boosts the voltage to a voltage according to the output and a motor drive circuit that converts the output voltage of the converter into a drive voltage of the motor according to the drive force command value. The control method includes a step of determining a sharing ratio of the driving force generated by the internal combustion engine and the motor so that the required driving force of the vehicle is output to the driving shaft, and setting a driving force command value according to the determined sharing ratio; Depending on the driving state of the vehicle, the voltage command value is set according to the driving force command value with either one of the first voltage and the second voltage lower than the first voltage as an upper limit value, and the driving force Controlling the current flowing through the motor based on the command value and the output voltage of the converter. The step of setting the driving force command value according to the sharing ratio includes the step of acquiring the temperature of the motor, setting the voltage command value with the second voltage as the upper limit value, and based on the driving force command value and the output voltage of the converter A step of changing the determined sharing ratio so that the driving force generated by the motor is reduced when the temperature of the motor exceeds a predetermined reference temperature when the current flowing through the motor is controlled. .

  Preferably, the step of changing the sharing ratio has a ratio of the second voltage to the first voltage as a predetermined correction coefficient in advance, and the driving force command value is multiplied by the predetermined correction coefficient. A step of correcting

  Preferably, the hybrid vehicle mechanically couples an input shaft that receives power from the internal combustion engine, a rotation shaft of the motor, and a drive shaft, and mechanically distributes the power from the internal combustion engine to the motor and the drive shaft. It further includes a configured power split mechanism. The step of changing the sharing ratio is requested by a driving force generated by the motor according to the corrected driving force command value and a direct driving force that is a driving force transmitted from the internal combustion engine to the driving shaft through the power split mechanism. The method further includes the step of controlling the internal combustion engine such that the driving force based on the driving force acts on the drive shaft.

  Preferably, the step of controlling the internal combustion engine increases the direct drive force with a change in the operation point of the internal combustion engine.

  Preferably, the step of changing the sharing ratio includes setting the upper limit value of the voltage command value to the first value when the sum of the direct drive force acting on the drive shaft and the drive force generated by the motor does not satisfy the required drive force. Change to voltage.

  According to the present invention, in a configuration in which a converter capable of boosting the voltage is arranged so that the input voltage of the motor drive circuit that drives and controls the motor for driving the wheel is variable, the motor is prevented from being overheated due to the reduction in power loss. can do. As a result, fuel efficiency can be improved without degrading the running performance of the vehicle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

(Schematic configuration of the vehicle)
FIG. 1 is a block diagram illustrating a configuration of a hybrid vehicle according to an embodiment of the present invention.

  Referring to FIG. 1, a hybrid vehicle 100 according to the present invention includes a battery 10, a hybrid ECU (Electronic Control Unit) 15, a PCU (Power Control Unit) 20, a power output device 30, and a differential gear (Differential Gear). 40, front wheels 50L and 50R, rear wheels 60L and 60R, front seats 70L and 70R, and a rear seat 80.

  The battery 10 is formed of a secondary battery such as nickel metal hydride or lithium ion, for example, and supplies a DC voltage to the PCU 20 and is charged by the DC voltage from the PCU 20. The battery 10 is disposed, for example, at the rear portion of the rear seat 80 and is electrically connected to the PCU 20. The PCU 20 collectively indicates power converters required in the hybrid vehicle 100.

  Various sensor outputs 17 from various sensors indicating driving conditions and vehicle conditions are input to the hybrid ECU 15. The various sensor outputs 17 include an accelerator opening, a wheel speed sensor output, and the like corresponding to an accelerator depression amount detected by a position sensor disposed on the accelerator pedal 35. The hybrid ECU 15 comprehensively performs various controls relating to the hybrid vehicle 100 based on these input sensor outputs.

  Power output device 30 is provided as a wheel driving force source, and includes an engine and / or motor generators MG1 and MG2. These are mechanically coupled via a power split mechanism PSD (FIG. 2). Then, according to the traveling state of the hybrid vehicle 100, the driving force is distributed and combined among the three parties via the power split mechanism PSD, and as a result, the front wheels 50L and 50R are driven. The DG 40 transmits the power from the power output device 30 to the front wheels 50L and 50R, and transmits the rotational force of the front wheels 50L and 50R to the power output device 30.

  Thereby, motive power output device 30 transmits the power from engine and / or motor generators MG1, MG2 to front wheels 50L, 50R via DG 40 to drive front wheels 50L, 50R. In addition, power output device 30 generates power by the rotational force of motor generators MG1 and MG2 by front wheels 50L and 50R, and supplies the generated power to PCU 20.

  Motor generators MG1 and MG2 can function as both a generator and an electric motor, but motor generator MG1 mainly operates as a generator, and motor generator MG2 mainly operates as an electric motor.

  Specifically, motor generator MG1 is used as a starter that starts the engine during acceleration. At this time, motor generator MG1 is supplied with electric power from battery 10 and is driven as an electric motor, and cranks and starts the engine.

  Further, after the engine is started, motor generator MG1 is rotated by the driving force of the engine transmitted through the power split mechanism to generate electric power.

  Motor generator MG2 is driven by at least one of the electric power stored in battery 10 and the electric power generated by motor generator MG1. The driving force of motor generator MG2 is transmitted to the driving shafts of front wheels 50L and 50R via DG40. Thereby, motor generator MG2 assists the engine to travel the vehicle, or travels the vehicle only by its own driving force.

  At the time of regenerative braking of the vehicle, motor generator MG2 is driven by front wheels 50L and 50R to operate as a generator. At this time, the regenerative power generated by motor generator MG2 is charged to battery 10 via PCU 20.

  PCU 20 boosts the DC voltage from battery 10 and converts the boosted DC voltage into an AC voltage in accordance with a control instruction from hybrid ECU 15 during powering operation of motor generators MG 1, MG 2. Drive control of included motor generators MG1, MG2 is performed.

  In addition, during regenerative braking of motor generators MG1 and MG2, PCU 20 charges battery 10 by converting the AC voltage generated by motor generators MG1 and MG2 into a DC voltage in accordance with a control instruction from hybrid ECU 15.

  Thus, in hybrid vehicle 100, “power supply device” that drives and controls motor generators MG <b> 1 and MG <b> 2 is configured by battery 10, PCU 20, and part of hybrid ECU 15 that controls PCU 20.

Next, the configuration of the power supply device according to the present invention will be described.
FIG. 2 is a block diagram showing the configuration of the power supply device according to the present invention.

  Referring to FIG. 2, a power supply device according to the present invention includes a battery 10 corresponding to a “power source” and a portion related to drive control of motor generators MG1 and MG2 in PCU 20 (hereinafter, this portion is also simply referred to as “PCU 20”. And a portion for controlling the PCU 20 in the hybrid ECU 15.

  PCU 20 includes system main relays SMR1, SMR2, converter 110, smoothing capacitor C2, inverters 114, 112 corresponding to motor generators MG1, MG2, respectively, temperature sensor 124, and MGECU 140.

  System main relays SMR1, SMR2 conduct / cut off the power supply path from battery 10 to inverters 112, 114. Specifically, system main relay SMR 1 is connected between the positive electrode of battery 10 and power supply line 101. System main relay SMR <b> 2 is connected between the negative electrode of battery 10 and ground line 102. System main relays SMR1 and SMR2 are turned on / off (on / off) by signal SE from MGECU 140, respectively.

  For example, converter 110 includes a step-up / step-down chopper circuit, and includes a reactor L1, power semiconductor switching elements (hereinafter also simply referred to as switching elements) Q1 and Q2, and diodes D1 and D2.

  Switching elements Q 1 and Q 2 are connected in series between power supply line 103 and earth line 102. Reactor L1 is connected between power supply line 101 and a connection node of switching elements Q1 and Q2. Anti-parallel diodes D1 and D2 are connected between the emitters / collectors of switching elements Q1 and Q2, respectively, so that current flows from the emitter side to the collector side.

  A gate control signal corresponding to the switching control signal PWMC is applied to the gates of the switching elements Q1 and Q2, respectively, and on / off of the switching elements Q1 and Q2 is controlled in response to the gate control signal. As the switching element in this embodiment, for example, an IGBT (Insulated Gate Bipolar Transistor) is applied.

  Converter 110 receives input voltage Vb from battery 10 between power supply line 101 and earth line 102, boosts input voltage Vb by switching control of switching elements Q1 and Q2, and applies an applied voltage for driving the motor ( (Hereinafter also referred to as “motor operating voltage”) and generated between the power line 103 and the earth line 102. The step-up ratio (Vm / Vb) in converter 110 is determined according to the ON period ratio (duty ratio) of switching elements Q1 and Q2.

  Therefore, MGECU 140 generates voltage command value Vm * of motor operating voltage Vm based on torque command values Tm1 *, Tm2 * of motor generators MG1, MG2 from hybrid ECU 15, and based on the generated voltage command value Vm *. Thus, the step-up ratio in converter 110 is determined. Then, MGECU 140 generates switching control signal PWMC so that this boost ratio is realized.

  Smoothing capacitor C <b> 2 is connected between power supply line 103 and earth line 102, smoothes motor operating voltage Vm output from converter 110, and supplies it to inverters 112 and 114. Voltage sensor 122 detects voltage (motor operating voltage) Vm across smoothing capacitor C2, and outputs the detected voltage Vm to MGECU 140.

  Inverter 112 converts motor operating voltage Vm output from converter 110 into three-phase alternating current and outputs it to motor generator MG2 that drives the wheels. Inverter 112 returns the electric power generated in motor generator MG2 to converter 110 in accordance with regenerative braking. At this time, converter 110 is controlled by MGECU 140 so as to operate as a step-down circuit.

  Inverter 112 is a three-phase inverter composed of switching elements Q <b> 3 to Q <b> 8 constituting U-phase arm 115, V-phase arm 116, and W-phase arm 117 connected in parallel between power supply line 103 and earth line 102. Anti-parallel diodes D3-D8 are connected between the collectors / emitters of switching elements Q3-Q8, respectively.

  An intermediate point of each phase arm of inverter 112 is connected to each phase end of each phase coil of motor generator MG2 which is a three-phase permanent magnet motor. One end of each phase coil is commonly connected to the neutral point. Although illustration is omitted, a current sensor is provided in at least two of the three phases, and each phase current can be detected.

  Temperature sensor 124 detects motor temperature TEm2 of motor generator MG2, and outputs the detected motor temperature TEm2 to hybrid ECU 15.

  Inverter 114 is connected to converter 110 in parallel with inverter 112. Inverter 114 converts motor operating voltage Vm output from converter 110 to motor generator MG1 into a three-phase alternating current and outputs the same. Inverter 114 receives motor operating voltage Vm boosted from converter 110, and drives motor generator MG1 to start the engine, for example.

  Inverter 114 returns electric power generated by motor generator MG1 to converter 110 by rotational torque transmitted from crankshaft 50 of the engine. At this time, converter 110 is controlled by MGECU 140 so as to operate as a step-down circuit. Although the internal configuration of inverter 114 is not shown, it is similar to inverter 112, and detailed description will not be repeated.

  Based on the various sensor outputs 17, hybrid ECU 15 generates operation commands for motor generators MG1 and MG2 and outputs them to MGECU 140 so that desired driving force generation and power generation are performed. This operation command includes an operation permission / prohibition instruction for each motor generator MG1, MG2, torque command values Tm1 *, Tm2 *, a rotational speed command, and the like.

  MGECU 140 follows a driving command from hybrid ECU 15 by feedback control based on a motor current of each phase and a detected value of the rotation angle of the rotor from a current sensor and a position sensor (both not shown) arranged in motor generator MG1. A switching control signal PWMI1 for controlling the switching operation of switching elements Q3 to Q8 is generated so that motor generator MG1 operates.

  Further, MGECU 140 operates from hybrid ECU 15 by feedback control based on the detected values of the motor current of each phase and the detected rotation angle of the rotor from a current sensor and a position sensor (both not shown) arranged in motor generator MG2. A switching control signal PWMI2 for controlling the switching operation of switching elements Q3 to Q8 is generated so that motor generator MG2 operates in accordance with the command.

  Further, MGECU 140 calculates voltage command value Vm * of motor operating voltage Vm for increasing the efficiency of motor generators MG1 and MG2 based on the operation command from hybrid ECU 15. Then, MGECU 140 determines the boost ratio in converter 110 based on the calculated voltage command value Vm *, and generates switching control signal PWMC so that this boost ratio is realized.

  Further, MGECU 140 generates switching control signal PWMC so as to step down DC voltage (motor operating voltage Vm) supplied from inverters 112 and 114 during regenerative braking of hybrid vehicle 100. That is, at the time of regenerative braking, converter 110 turns on / off switching elements Q1 and Q2 in response to switching control signal PWMC, thereby stepping down motor operating voltage Vm and reducing the DC voltage between power supply line 101 and ground line 102. Output to. Battery 10 is charged with a DC voltage from converter 110. Thus, the converter 110 can also step down the motor operating voltage Vm to a DC voltage, and thus has a bidirectional converter function.

  FIG. 3 is a schematic diagram for explaining details of the power split mechanism PSD and the speed reducer RD in FIG. 2.

  Referring to FIG. 3, hybrid vehicle 100 includes a motor generator MG2, a reduction gear RD connected to the rotation shaft of motor generator MG2, and an axle that rotates in accordance with the rotation of the rotation shaft decelerated by reduction gear RD. , Engine 4, motor generator MG 1, reduction gear RD, and power split mechanism PSD that distributes power between engine 4 and motor generator MG 1. Reducer RD has a reduction ratio from motor generator MG2 to power split device PSD of, for example, twice or more.

  The crankshaft 50 of the engine 4, the rotor 32 of the motor generator MG1, and the rotor 37 of the motor generator MG2 rotate about the same axis.

  The power split mechanism PSD is a planetary gear in the example shown in FIG. 3, and is supported so as to be rotatable coaxially with the sun gear 51 coupled to a hollow sun gear shaft penetrating the crankshaft 50 through the shaft center. The ring gear 52 is disposed between the sun gear 51 and the ring gear 52, and revolves while rotating around the outer periphery of the sun gear 51. The pinion gear 53 is coupled to the end of the crankshaft 50 and supports the rotation shaft of each pinion gear 53. A planetary carrier 54.

  In the power split mechanism PSD, a sun gear shaft coupled to the sun gear 51, a ring gear case coupled to the ring gear 52, and a crankshaft 50 coupled to the planetary carrier 54 serve as power input / output shafts. When the power input / output to / from any two of the three axes is determined, the power input / output to the remaining one axis is determined based on the power input / output to the other two axes.

  A counter drive gear 70 for taking out power is provided outside the ring gear case, and rotates integrally with the ring gear 52. Counter drive gear 70 is connected to power transmission reduction gear RG. Power is transmitted between the counter drive gear 70 and the power transmission reduction gear RG. The power transmission reduction gear RG drives the differential gear DG. On the downhill or the like, the rotation of the wheel is transmitted to the differential gear DG, and the power transmission reduction gear RG is driven by the differential gear DG.

  Motor generator MG1 includes a stator 31 that forms a rotating magnetic field, and a rotor 32 that is disposed inside stator 31 and has a plurality of permanent magnets embedded therein. The stator 31 includes a stator core 33 and a three-phase coil 34 wound around the stator core 33. Rotor 32 is coupled to a sun gear shaft that rotates integrally with sun gear 51 of power split device PSD. The stator core 33 is formed by laminating thin magnetic steel sheets.

  Motor generator MG1 operates as an electric motor that rotationally drives rotor 32 by the interaction between the magnetic field generated by the permanent magnet embedded in rotor 32 and the magnetic field formed by three-phase coil 34. Motor generator MG1 also operates as a generator that generates electromotive force at both ends of three-phase coil 34 due to the interaction between the magnetic field generated by the permanent magnet and the rotation of rotor 32.

  Motor generator MG2 includes a stator 36 that forms a rotating magnetic field, and a rotor 37 that is disposed inside stator 36 and has a plurality of permanent magnets embedded therein. The stator 36 includes a stator core 38 and a three-phase coil 39 wound around the stator core 38.

  The rotor 37 is coupled to a ring gear case that rotates integrally with the ring gear 52 of the power split mechanism PSD by a reduction gear RD. Stator core 38 is formed, for example, by laminating thin magnetic steel sheets.

  Motor generator MG2 also operates as a generator that generates electromotive force at both ends of three-phase coil 39 by the interaction between the magnetic field generated by the permanent magnet and the rotation of rotor 37. Motor generator MG2 operates as an electric motor that rotationally drives rotor 37 by the interaction between the magnetic field generated by the permanent magnet and the magnetic field formed by three-phase coil 39.

  The speed reducer RD performs speed reduction by a structure in which a planetary carrier 66 that is one of rotating elements of a planetary gear is fixed to a case of a vehicle drive device. That is, the reduction gear RD includes a sun gear 62 coupled to the shaft of the rotor 37, a ring gear 68 that rotates integrally with the ring gear 52, and a pinion gear 64 that meshes with the ring gear 68 and the sun gear 62 and transmits the rotation of the sun gear 62 to the ring gear 68. Including.

  For example, by making the number of teeth of the ring gear 68 more than twice that of the sun gear 62, the reduction ratio can be made more than twice.

(Control structure)
In the hybrid vehicle 100 configured in this manner, the hybrid ECU 15 requires the required torque Tr * to be output to the ring gear 52 as the drive shaft based on the accelerator opening Acc corresponding to the depression amount of the accelerator pedal 35 by the driver and the vehicle speed V. Is calculated. Then, the engine 4 and the motor generators MG1 and MG2 are operated and controlled so that the driving force corresponding to the required torque Tr * is output to the ring gear 52.

  Furthermore, in the present embodiment, in such operation control, the hybrid ECU 15 performs “normal driving mode” in which normal driving is performed according to the driving state of the vehicle, and “fuel consumption that prioritizes fuel consumption over the normal driving mode”. Select "Priority Mode".

  Specifically, in the normal travel mode, a sufficient driving force for driving the vehicle is quickly applied even when the load suddenly fluctuates according to the driving state of the vehicle (accelerator opening Acc, vehicle speed V, etc.). By generating it, the running performance of the vehicle is ensured. Therefore, it is suitable when a large driving force is required, for example, when starting a vehicle or traveling on a slope.

  In contrast, the fuel efficiency priority mode is intended to improve fuel efficiency while maintaining smooth running of the vehicle when the load fluctuation is relatively small. Therefore, the fuel efficiency priority mode is suitable when the required driving force is relatively small, for example, when the vehicle travels at a low speed in an urban area.

  Note that the driving state of the vehicle includes, as an example, an input signal from an eco switch (not shown) for receiving a low fuel consumption travel instruction from the driver. The eco switch is a push button type switch installed in the vicinity of the driver's seat in the passenger compartment, for example, and can be switched between the normal driving mode and the fuel efficiency priority mode when operated by the driver (push). Composed.

  As another example, as shown in FIG. 4, the hybrid ECU 15 monitors the driving operation of the driver based on various sensor outputs 17, and the normal driving mode and the fuel efficiency priority are determined according to the presence or absence of the sudden acceleration / deceleration operation. Switch between modes.

  FIG. 4 is a flowchart illustrating an example of a travel control routine executed by the hybrid ECU 15. This routine is repeatedly executed every predetermined time.

  Referring to FIG. 4, when the travel control routine is executed, hybrid ECU 15 first determines the presence or absence of a sudden acceleration / deceleration operation by the driver based on various sensor outputs 17 that are input (step S01). At this time, for example, when it is detected that the accelerator opening degree Acc is greater than or equal to a predetermined threshold, the steering wheel steering angle is greater than or equal to the predetermined threshold, or the brake pedaling force is greater than or equal to the predetermined threshold, the hybrid ECU 15 It is determined that there is a sudden acceleration / deceleration operation. In this case, the hybrid ECU 15 selects the normal travel mode as the vehicle travel mode (step S04).

  On the other hand, when the accelerator opening degree Acc, the steering wheel steering angle, and the brake pedal force are below the predetermined threshold values, the hybrid ECU 15 determines that there is no sudden acceleration / deceleration operation. In this case, the hybrid ECU 15 selects the fuel efficiency priority mode as the vehicle travel mode (step S02).

  Then, when the travel mode is selected in steps S02 and S04, hybrid ECU 15 executes boost control of converter 110 adapted to the selected travel mode.

  Specifically, hybrid ECU 15 variably sets an upper limit value (hereinafter also referred to as a motor operating voltage upper limit value) Vmmax of output voltage (motor operating voltage) Vm of converter 110 according to the selected travel mode.

  Specifically, when the normal travel mode is selected, the hybrid ECU 15 sets the motor operating voltage upper limit value Vmmax to a predetermined value V1 (step S05). The predetermined value V1 is set to the maximum voltage of the power supply device, for example. Thus, MGECU 140 sets motor operation voltage Vm as a voltage command based on torque command values Tm1 * and Tm2 * of motor generators MG1 and MG2 and the motor rotation speed with motor operation voltage upper limit value Vmmax (= V1) as an upper limit value. The value Vm * is generated. Based on the generated voltage command value Vm *, the boost ratio in converter 110 is determined, and switching control signal PWMC is generated so that this boost ratio is realized.

  On the other hand, when the fuel efficiency priority mode is selected, the hybrid ECU 15 sets the motor operating voltage upper limit value Vmmax to a voltage V2 lower than the predetermined value V1 (step S03). The predetermined value V2 is set to a voltage lower than the maximum voltage of the power supply device, for example, with the input voltage (battery voltage) Vb from the battery 10 as a lower limit. Thereby, MGECU 140 sets motor command voltage Vm as a command based on torque command values Tm1 * and Tm2 * of motor generators MG1 and MG2 and the motor rotation speed with motor operation voltage upper limit value Vmmax (= V2) as the upper limit value. The value Vm * is generated. Based on the generated voltage command value Vm *, the boost ratio in converter 110 is determined, and switching control signal PWMC is generated so that this boost ratio is realized.

  Thus, in the fuel consumption priority mode, the loss generated in converter 110 can be reduced by limiting upper limit value Vmmax of motor operating voltage Vm output from converter 110. As a result, the energy efficiency of the hybrid vehicle 100 can be improved.

  Specifically, the loss in converter 110 is mainly the sum of the loss in switching elements Q1 and Q2 and the loss in reactor L1. In any case, the loss becomes smaller as the converter passing current (that is, the battery current) is smaller and the motor operating voltage Vm is lower. Further, when the ripple current increases, the loss depending on the square of the current increases, so that the voltage difference | Vm−Vb | is one of the factors that determine the loss in the converter 110. That is, the loss in converter 110 becomes a value proportional to the square of the battery current, and increases as the voltage difference | Vm−Vb | increases. That is, in the fuel efficiency priority mode, the voltage difference is smaller than in the normal travel mode, so that loss can be reduced.

  However, in this fuel efficiency priority mode, compared to the normal travel mode, the current flowing through each phase coil of motor generators MG1 and MG2 increases to output the same required torque as motor operating voltage Vm is limited. It will be. Therefore, in motor generators MG1 and MG2, the motor temperature becomes relatively high due to an increase in the amount of heat generation. In particular, when the load suddenly fluctuates due to a rapid acceleration / deceleration operation by the driver during execution of the fuel efficiency priority mode, as described below, the amount of heat generation becomes excessive, so that the motor generators MG1, MG2 are overheated. May occur.

  FIG. 5 is a diagram showing a temporal change in the motor temperature TEm2 of the motor generator MG2. Hereinafter, a case where motor generator MG2 is overheated among motor generators MG1 and MG2 will be described. This is because motor generator MG2 has a relatively larger amount of heat generation than motor generator MG1.

  Referring to FIG. 5, line LN1 indicates motor temperature TEm2 of motor generator MG2 when the normal travel mode is being executed, and line LN2 indicates motor temperature TEm2 when the fuel efficiency priority mode is being executed.

  First, it is assumed that the hybrid vehicle 100 is traveling at a low speed in an urban area. At this time, a motor current corresponding to the torque command value Tm2 * passes through each phase coil of the motor generator MG2 by the feedback control by the inverter 112 described above. Since the load fluctuation is relatively small in urban driving, the motor temperature TEm2 gradually increases and converges to a substantially constant level after time t0. In the following, the convergence value of the motor temperature TEm2 when traveling in an urban area is also referred to as an urban area saturation temperature.

  Comparing the urban saturation temperature at this time between the normal travel mode and the fuel efficiency priority mode, the fuel efficiency priority mode execution (corresponding to the temperature TE2) is higher than the normal travel mode execution (corresponding to the temperature TE1). I understand. This is because the motor current is increased by limiting the motor operating voltage Vm as described above.

  Here, it is assumed that a rapid acceleration / deceleration operation is performed by the driver at time t2. In FIG. 5, it is assumed that the accelerator opening degree Acc is operated to the fully open position WOT (Wide Open Throttle) by the driver.

  In this case, the hybrid ECU 15 switches the vehicle travel mode from the fuel efficiency priority mode to the normal travel mode according to the travel control routine of FIG. Further, hybrid ECU 15 generates torque command values Tm1 *, Tm2 * for motor generators MG1, MG2 based on accelerator opening Acc, vehicle speed V, and the like, and outputs them to MGECU 140.

  The MGECU 140 generates a voltage command value Vm * based on the torque command values Tm1 *, Tm2 * and the motor speed, and changes the input voltage Vb to the motor operating voltage Vm so that the output voltage Vm matches the voltage command value Vm *. A switching control signal PWMC for boosting is generated. Further, MGECU 140 controls the motor current that flows through each phase of motor generators MG1 and MG2 so that motor generators MG1 and MG2 output the designated torque.

  At this time, in motor generator MG2, the amount of heat generation increases as the motor current increases. Therefore, in the example of FIG. 5, the motor temperature TEm2 may eventually increase by ΔT with respect to the urban saturation temperature TE2, and may exceed a predetermined allowable temperature TEm_lim that guarantees the motor performance of the motor generator MG2. Can happen. When motor temperature TEm2 exceeds predetermined allowable temperature TEm_lim, the output torque of motor generator MG2 decreases. As a result, the power output device 30 (FIG. 1) cannot generate a sufficient driving force for driving the vehicle, and it becomes difficult to ensure the traveling performance of the vehicle.

  On the other hand, in the normal travel mode, the motor temperature TEm2 increases after the time t2, and finally increases by ΔT with respect to the urban area saturation temperature TE1. However, since the urban area saturation temperature TE1 itself is low, the motor temperature TEm2 is suppressed to a temperature lower than a predetermined allowable temperature TEm_lim.

  Therefore, if the urban saturation temperature TE2 at the time of execution of the fuel consumption travel mode can be lowered to a level equivalent to the urban saturation temperature TE1 at the time of execution of the normal travel mode, the motor temperature TEm2 is allowed even if a sudden load fluctuation occurs. Reaching the temperature TEm_lim can be suppressed.

  Therefore, in the present embodiment, when the fuel efficiency priority mode is executed, the torque command value Tm2 * of the motor generator MG2 is set to the accelerator opening Acc and the vehicle speed V in response to the motor temperature TEm2 exceeding the predetermined reference temperature TEm_std. It is set as the structure corrected so that it may reduce rather than the torque command value calculated based on this.

  Specifically, the corrected torque command value Tm2 * d is multiplied by a predetermined correction coefficient k to the torque command value Tm2 * calculated based on the accelerator opening Acc and the vehicle speed V according to the equation (1). To be derived. The predetermined correction coefficient k is set to a ratio (= V2 / V1) of the motor operating voltage upper limit value Vmmax between the normal travel mode and the fuel efficiency priority mode.

Tm2 * d = Tm2 * × k = Tm2 * × (V2 / V1) (1)
Thus, the motor current flowing in each phase of motor generator MG2 during execution of the fuel efficiency priority mode decreases according to the correction coefficient k, and becomes substantially equal to the motor current during execution of the normal travel mode. As a result, the heat generation amount of motor generator MG2 when executing the fuel consumption travel mode is substantially maintained at substantially the same level as the heat generation amount when executing normal travel mode.

  On the other hand, simply reducing the torque command value Tm2 * may not ensure the driving force required for the vehicle. Therefore, in the present embodiment, the decrease in torque command value Tm2 * with respect to the required torque is compensated with direct torque, which is the torque that is mechanically directly transmitted from engine 4 to ring gear 52 via power split mechanism PSD. In this way, the configuration is such that a lack of driving force in the entire vehicle is avoided.

  That is, in the operation control of the engine and the motor generator according to the present embodiment, the motor generator MG2 and the engine 4 are controlled according to the motor temperature TEm2 of the motor generator MG2 exceeding the predetermined reference temperature TEm_std when the fuel efficiency priority mode is executed. Are changed so that the output torque of the motor generator MG2 is reduced. Hereinafter, such control is also referred to as “MG2 torque sharing ratio reduction control”.

  FIG. 6 is a diagram illustrating a temporal change in the motor temperature TEm2 when the MG2 torque sharing ratio reduction control is performed.

  Referring to FIG. 6, when hybrid vehicle 100 is traveling in an urban area, motor temperature TEm2 gradually increases. The motor temperature TEm2 is detected by the temperature sensor 124 (FIG. 2) and input to the hybrid ECU 15.

  The hybrid ECU 15 determines whether or not the motor temperature TEm2 from the temperature sensor 124 exceeds a predetermined reference temperature TEm_std. The predetermined reference temperature TEm_std is set to, for example, the urban area saturation temperature TE1 when the normal travel mode is executed. When the motor temperature TEm2 exceeds a predetermined reference temperature TEm_std at time t1, the hybrid ECU 15 starts the above-described MG2 torque sharing ratio reduction control. At this time, hybrid ECU 15 corrects torque command value Tm2 * of motor generator MG2 in accordance with equation (1) above.

  As a result, after time t1, the heat generation amount of motor generator MG2 becomes substantially the same as the heat generation amount in the normal travel mode, so that motor temperature TEm2 converges to urban area saturation temperature TE1 in the normal travel mode execution. . Therefore, even when the accelerator opening degree Acc is operated to the fully open position WOT at the time t2, the motor temperature TEm2 can be prevented from exceeding the predetermined allowable temperature TEm_lim.

(MG2 torque sharing ratio reduction control)
Hereinafter, MG2 torque sharing ratio reduction control according to the present embodiment will be described in detail.

  FIG. 7 is a collinear diagram showing the dynamic relationship between the rotational speed and torque of each rotary element of the power split mechanism PSD. The vertical axis represents the number of rotations of each rotary shaft, and the horizontal axis represents the gear ratio of each gear in a distance relationship.

  Referring to FIG. 7, the S axis indicates the rotation speed of sun gear 51, the C axis indicates the rotation speed of crankshaft 50, and the R axis indicates the rotation speed Nr of ring gear 52.

  On the R axis, a required torque Tr * to be output to the ring gear 52 connected to the drive shaft is shown. The required torque Tr * is set by the hybrid ECU 15 based on the accelerator opening Acc and the vehicle speed V input.

  Specifically, the hybrid ECU 15 predetermines the relationship among the accelerator opening Acc, the vehicle speed V, and the required torque Tr * and stores it in a ROM (Read Only Memory) as a required torque setting map. When the vehicle speed V is given, the corresponding required torque Tr * is derived and set from the stored map.

  Further, when the hybrid ECU 15 sets the required power Pe * to be output from the engine 4 based on the required torque Tr *, the set required power Pe * and an operation line (optimum fuel consumption line) for operating the engine 4 efficiently. Based on the above, the target rotational speed Ne * and target torque Te * of the engine 4 are set.

  Here, as described above, the rotational speed of the sun gear 51 is the rotational speed Nm1 of the motor generator MG1, and the rotational speed of the crankshaft 50 is the rotational speed Ne of the engine. Therefore, the target rotational speed Nm1 * of the motor generator MG1 Can be calculated by the formula (2) based on the rotational speed Nr of the ring gear, the target rotational speed Ne * of the engine, and the gear ratio ρ of the power split mechanism PSD.

Nm1 * = (Ne * · (1 + ρ) −Nr) / ρ (2)
Therefore, the engine 4 can be rotated at the target rotational speed Ne * by setting the torque command value Tm1 * so that the motor generator MG1 rotates at the target rotational speed Nm1 * and drivingly controlling the motor generator MG1.

  At this time, on the R axis in FIG. 6, the torque command value Tm2 *, which is the torque to be output from the motor generator MG2, is added to the torque acting on the ring gear 52, and the engine 4 is operated while receiving the reaction force at the motor generator MG1. A torque Ter (= −Tm1 * / ρ) in which the torque Te * output from the engine 4 is transmitted to the ring gear 52 when the engine is operated at the operation point with the target rotational speed Ne * and the target torque Te * is shown. Hereinafter, this is also referred to as a direct torque Ter.

  MG2 torque sharing ratio reduction control according to the present embodiment reduces torque command value Tm2 * of motor generator MG2 in the dynamic relationship shown in FIG. 7, and compensates the decrease with direct torque Ter. It is.

  Here, if an attempt is made to compensate the decrease in the torque command value Tm2 * with the direct torque Ter, it may be necessary to reset the target operating point of the engine 4. FIG. 8 is a diagram illustrating an example of an operation line of the engine 4 and a state in which a target operation point is set.

  Referring to FIG. 8, the target rotational speed Ne * and the target torque Te * are calculated as follows: an operation line (optimum fuel consumption line) for efficiently operating the engine 4 and a required power Pe * (= Ne **). Te *) can be obtained from the intersection (corresponding to point P1 in the figure) with a constant curve.

  In contrast, in the MG2 torque sharing ratio reduction control, the target operating point (point) is set so that the sum of the corrected torque command value Tm2 * d and the direct torque Tor from the engine 4 is equal to the required torque Tr *. The rotation speed and torque (corresponding to the point P2 in the figure) different from the target rotation speed Ne * and the target torque Te * in P1) are reset as the target rotation speed Ne * and the target torque Te *. As a result, the engine 4 is operated at the changed operation point in which the rotation speed and the torque are changed from the target operation point.

  Note that even if the decrease in the torque command value Tm2 * of the motor generator MG2 can be compensated by changing the operation point of the engine 4 from the target operation point, the efficiency of the engine 4 is reduced, so that the hybrid vehicle There is a possibility of deteriorating the fuel consumption of 100. Therefore, the changed operation point needs to be set within a range where improvement in fuel efficiency can be expected after comparing the efficiency decrease of the engine 4 and the efficiency increase due to the fuel efficiency priority mode.

The above processing can be summarized in a processing flow as shown in FIGS.
(flowchart)
9 and 10 are a flowchart illustrating a drive control routine executed by hybrid ECU 15 according to the embodiment of the present invention. This routine is repeatedly executed every predetermined time.

  Referring to FIG. 9, when the drive control routine is executed, the hybrid ECU 15 determines the accelerator opening Acc, the vehicle speed V, and the engine 4 corresponding to the depression amount of the accelerator pedal 35 (FIG. 1) as various sensor outputs 17. Processing for inputting data necessary for control including the rotational speed Ne, the rotational speeds Nm1, Nm2 of the motor generators MG1, MG2, and the motor operating voltage upper limit value Vmmax set in the travel control routine of FIG. 4 is performed (step S11). ). Note that the rotation speed Ne of the engine 4 is input as detected by a rotation speed sensor attached to the crankshaft 50 (FIG. 3). Motor generators MG1 and MG2 have rotational speeds Nm1 and Nm2 calculated based on an input signal from a rotational position sensor that detects the rotational positions of the rotors of motor generators MG1 and MG2, and are input by MGECU 140. .

  When the data is thus input, the hybrid ECU 15 determines the required torque Tr * to be output to the ring gear 52 as the drive shaft and the required power Pe * to be output from the engine 4 based on the input accelerator opening Acc and the vehicle speed V. Is set (step S12). At this time, the required torque Tr * is set by deriving the required torque Tr * corresponding to the accelerator opening Acc and the vehicle speed V from the required torque setting map stored in the ROM as described above. Further, the required power Pe * is set by the sum of the required torque Tr * multiplied by the rotational speed Nr of the ring gear 52 and the loss Loss.

  Next, when the required power Pe * is set, the hybrid ECU 15 sets the target rotational speed Ne * of the engine 4 based on the set required power Pe * and an operation line (FIG. 8) for operating the engine 4 efficiently. And the target torque Te * are set (step S13).

  Further, the hybrid ECU 15 uses the target rotational speed Ne * set in step S13, the rotational speed Nr of the ring gear 52, and the gear ratio ρ of the power split mechanism PSD to calculate the target of the motor generator MG1 according to the above equation (2). Set the speed Nm1 *. Hybrid ECU 15 sets torque command value Tm1 * of motor generator MG1 by the following equation (3) based on the set target rotation speed Nm1 * and current rotation speed Nm1 (step S14). Here, Expression (3) is a relational expression in feedback control for rotating the motor generator MG1 at the target rotation speed Nm1 *.

Tm1 * = previous Tm1 * + PID (Nm1 *, Nm1) (3)
Next, hybrid ECU 15 is based on target rotational speed Nm1 * and torque command value Tm1 * of motor generator MG1, required torque Tr *, gear ratio ρ of power split mechanism PSD, and gear ratio Gr of reduction gear RD. Thus, a torque command value Tm2 * as a torque to be output from the motor generator MG2 to set the required torque Tr * on the ring gear 52 is set by the following equation (4) (step S15).

Tm2 * = (Tr * + Tm1 * / ρ) Gr (4)
When the target rotational speed Ne * and target torque Te * of engine 4 and torque command value Tm1 * of motor generators MG1 and MG2 are set in this way, hybrid ECU 15 uses temperature sensor 124 (FIG. 2) attached to motor generator MG2. The detected motor temperature TEm2 is input (step S16).

  Next, the hybrid ECU 15 determines whether or not the motor operating voltage upper limit value Vmmax is a predetermined value V2 (step S17). When motor operating voltage upper limit value Vmmax is not a predetermined value V2 (NO in step S17), hybrid ECU 15 determines that the traveling mode of the vehicle is the normal traveling mode. In this case, the hybrid ECU 15 determines that execution of MG2 torque sharing ratio reduction control, which will be described later, is unnecessary, and transmits the set target engine speed Ne * and target torque Te * to the engine ECU. Further, hybrid ECU 15 transmits torque command values Tm1 *, Tm2 * of motor generators MG1, MG2 to MGECU 14, and ends the drive control routine (step S20).

  Accordingly, the engine ECU that has received the target rotational speed Ne * and the target torque Te * performs fuel injection in the engine 4 so that the engine 4 is operated at the operating point indicated by the target rotational speed Ne * and the target torque Te *. Control and ignition control are performed.

  Further, MGECU 140 that has received torque command values Tm1 * and Tm2 * switches switching elements Q3 to Q8 that constitute each of inverters 112 and 114 such that motor generators MG1 and MG2 are driven in accordance with torque command values Tm1 * and Tm2 *. Switching control is performed. At this time, the MGECU 140 sets the motor operation voltage upper limit value Vmmax (= V1) as the upper limit value, and the voltage command value Vm * of the motor operation voltage Vm based on the torque command values Tm1 *, Tm2 * and the motor rotation speeds Nm1, Nm2. And switching control of switching elements Q1 and Q2 of converter 110 is performed according to the generated voltage command value Vm *.

  On the other hand, when the motor operating voltage upper limit value Vmmax is the predetermined value V2 in step S17 (YES in step S17), the hybrid ECU 15 determines that the vehicle travel mode is the fuel consumption priority mode. Subsequently, it is determined whether or not the motor temperature TEm2 is higher than a predetermined reference temperature TEm_std (step S18). When motor temperature TEm2 is equal to or lower than predetermined reference temperature TEm_std (NO in step S18), hybrid ECU 15 advances the process to step S20.

  On the other hand, when motor temperature TEm12 is higher than predetermined reference temperature TEm_std (YES in step S18), hybrid ECU 15 executes MG2 torque sharing ratio reduction control according to the processing flow shown in FIG. Step S19), the drive control routine is terminated.

  In the MG2 torque sharing ratio reduction control routine of FIG. 10, the hybrid ECU 15 multiplies the torque command value Tm2 * of the motor generator MG2 set in step S15 of FIG. 9 by a predetermined correction coefficient k (= V2 / V1). The torque command value Tm2 * is corrected (step S21).

  Next, the hybrid ECU 15 determines that the direct torque Ter is equal to the difference between the torque command value Tm2 * before correction and the torque command value Tm2 * d after correction (= Tm2 * × (1−V2 / V1)). The operating point of engine 4 and torque command value Tm1 * of motor generator MG1 are adjusted so as to increase (step S22). At this time, the hybrid ECU 15 compares the efficiency decrease caused by changing the operation point of the engine 4 from the target operation point with the efficiency increase due to execution of the fuel efficiency priority mode, and within a range where fuel efficiency improvement can be expected. The operating point of engine 4 and torque command value Tm1 * of motor generator MG1 are adjusted.

  Then, the hybrid ECU 15 determines that the sum of the direct torque Tor transmitted to the ring gear 52 by the adjusted operating point of the engine 4 and the torque command value Tm1 * of the motor generator MG1 and the corrected torque command value Tm2 * d is It is determined whether or not it falls below the required torque Tr * (step S23). If the sum of the direct torque Ter and the corrected torque command value Tm2 * d is less than the required torque Tr * (YES in step S23), the hybrid ECU 15 interrupts the execution of the fuel efficiency priority mode and performs motor operation. The voltage upper limit value Vmmax (= V2) is changed to the predetermined value V1 (step S24).

  On the other hand, when the sum of the direct torque Ter and the corrected torque command value Tm2 * d is equal to or greater than the required torque Tr * (NO in step S23), the hybrid ECU 15 causes the engine 4 to be adjusted. The target rotational speed Ne * and the target torque Te * are transmitted to the engine ECU. Further, hybrid ECU 15 transmits adjusted torque command value Tm1 * of motor generator MG1 and corrected torque command value Tm2 * d of motor generator MG2 to MGECU 14, and ends the drive control routine (step S20).

  The drive control of the engine and the motor generator by the hybrid ECU 15 is actually executed by a CPU (Central Processing Unit), and the CPU reads a program including the steps shown in FIGS. 9 and 10 from the ROM. And each step shown in FIG. 10 is performed, and an engine and a motor generator are drive-controlled.

  Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program for causing the computer CPU to execute drive control of the engine and the motor generator is recorded.

  As described above, according to the embodiment of the present invention, when the fuel efficiency priority mode is executed, it is possible to generate a driving force necessary for traveling of the vehicle while preventing overheating of the motor generator. As a result, fuel consumption can be improved without degrading the running performance of the vehicle.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be applied to a power supply device mounted on a hybrid vehicle.

1 is a block diagram illustrating a configuration of a hybrid vehicle according to an embodiment of the present invention. It is a block diagram which shows the structure of the power supply device by this invention. It is a schematic diagram for demonstrating the detail of the power split mechanism PSD and the reduction gear RD in FIG. It is a flowchart which shows an example of the traveling control routine performed by hybrid ECU. It is a figure which shows the time change of motor temperature TEm2 of motor generator MG2. It is a figure which shows the time change of motor temperature TEm2 at the time of performing MG2 torque share ratio reduction control. It is a collinear diagram which shows the dynamic relationship between the rotation speed of each rotation element of a power split device, and a torque. It is a figure which shows a mode that an example of an operation line of an engine and a target driving | operation point are set. It is a flowchart illustrating a drive control routine executed by a hybrid ECU according to the embodiment of the present invention. It is a flowchart illustrating an MG2 torque sharing ratio reduction control routine executed by the hybrid ECU according to the embodiment of the present invention.

Explanation of symbols

  4 Engine, 10 Battery, 15 Hybrid ECU, 17 Various sensor outputs, 30 Power output device, 31, 36 Stator, 32, 37 Rotor, 33, 38 Stator core, 34, 39 Three-phase coil, 35 Accelerator pedal, 50 Crankshaft, 50L, 50R Front wheel, 51, 62 Sun gear, 52, 68 Ring gear, 53, 64 Pinion gear, 54, 66 Planetary carrier, 60L, 60R Rear wheel, 70 Counter drive gear, 70L, 70R Front seat, 80 Rear seat, 100 Hybrid vehicle, 101, 103 Power line, 102 Ground line, 110 Converter, 112, 114 Inverter, 115 U-phase arm, 116 V-phase arm, 117 W-phase arm, 122 Voltage sensor, 124 Temperature sensor, Second smoothing capacitor, D1 to D8 antiparallel diodes, DG differential gear, L1 reactor, MG1, MG2 motor generator, Q1 to Q8 switching element, RD reduction gear, RG transmission reduction gear, SMR1, SMR2 system main relay.

Claims (10)

A control device for a hybrid vehicle that outputs power to a drive shaft as an internal combustion engine, a motor, and a power source,
The hybrid vehicle
Power supply,
A converter that boosts and outputs a DC voltage from the power source to a voltage according to a voltage command value;
A motor drive circuit that converts the output voltage of the converter into a drive voltage of the motor according to a drive force command value;
The control device includes:
A sharing ratio in which a driving force sharing ratio generated by the internal combustion engine and the motor is determined so that a required driving force of the vehicle is output to the driving shaft, and the driving force command value is set according to the determined sharing ratio. A ratio control means;
The voltage command value is set according to the driving force command value with the first voltage as an upper limit value, and the current flowing through the motor is controlled based on the driving force command value and the output voltage of the converter. Motor control means;
The voltage command value is set according to the driving force command value with a second voltage lower than the first voltage as an upper limit value, and based on the driving force command value and the output voltage of the voltage converter, Second motor control means for controlling the current flowing through the motor;
Selecting means for selectively executing the first and second motor control means according to the driving state of the vehicle;
The sharing ratio control means includes
Motor temperature acquisition means for acquiring the temperature of the motor;
If the temperature of the motor exceeds a predetermined reference temperature during the execution of the second motor control means, the determined sharing ratio is changed so that the driving force generated by the motor is reduced. A control device for a hybrid vehicle, including ratio changing means.   The sharing ratio changing unit has in advance a ratio of the second voltage to the first voltage as a predetermined correction coefficient, and the driving force command value is multiplied by the predetermined correction coefficient by multiplying the driving force command value. The control apparatus for a hybrid vehicle according to claim 1, comprising correction means for correcting the value. The hybrid vehicle
An input shaft that receives power from the internal combustion engine, a rotation shaft of the motor, and the drive shaft are mechanically coupled, and the power from the internal combustion engine is mechanically distributed to the motor and the drive shaft. A power split mechanism,
The sharing ratio changing means is
According to the corrected driving force command value, the required driving force is generated by the driving force generated by the motor and the direct driving force that is a driving force transmitted from the internal combustion engine to the drive shaft via the power split mechanism. The hybrid vehicle control device according to claim 2, further comprising a sharing ratio change-time control means for controlling the internal combustion engine so that a driving force based on the driving force acts on the drive shaft.   The control device for a hybrid vehicle according to claim 3, wherein the sharing ratio change time control means increases the direct drive force with a change of an operating point of the internal combustion engine.   The sharing ratio changing unit is configured when the sum of the direct drive force acting on the drive shaft and the drive force generated by the motor is less than the required drive force during execution of the second motor control unit. The control device for a hybrid vehicle according to claim 3, wherein an upper limit value of the voltage command value is changed to the first voltage. A control method for a hybrid vehicle that outputs power to a drive shaft as an internal combustion engine, a motor, and a power source,
The hybrid vehicle
Power supply,
A converter that boosts and outputs a DC voltage from the power source to a voltage according to a voltage command value;
A motor drive circuit that converts the output voltage of the converter into a drive voltage of the motor according to a drive force command value;
The control method is:
Determining a sharing ratio of driving forces generated by the internal combustion engine and the motor so that a required driving force of the vehicle is output to the driving shaft, and setting the driving force command value according to the determined sharing ratio When,
According to the driving state of the vehicle, the voltage command value is set according to the driving force command value with either one of the first voltage and the second voltage lower than the first voltage as an upper limit value. And a step of controlling a current flowing through the motor based on the driving force command value and an output voltage of the converter,
The step of setting the driving force command value according to the sharing ratio,
Obtaining a temperature of the motor;
While setting the voltage command value with the second voltage as an upper limit, and controlling the current flowing to the motor based on the driving force command value and the output voltage of the converter, the temperature of the motor is And a step of changing the determined sharing ratio so that the driving force generated by the motor is reduced when a predetermined reference temperature is exceeded.   The step of changing the sharing ratio has a ratio of the second voltage to the first voltage as a predetermined correction coefficient in advance, and multiplies the driving force command value by the predetermined correction coefficient to drive the drive The hybrid vehicle control method according to claim 6, comprising a step of correcting the force command value. The hybrid vehicle
An input shaft that receives power from the internal combustion engine, a rotation shaft of the motor, and the drive shaft are mechanically coupled, and the power from the internal combustion engine is mechanically distributed to the motor and the drive shaft. A power split mechanism,
The step of changing the sharing ratio includes:
According to the corrected driving force command value, the required driving force is generated by the driving force generated by the motor and the direct driving force that is a driving force transmitted from the internal combustion engine to the drive shaft via the power split mechanism. The hybrid vehicle control method according to claim 7, further comprising the step of controlling the internal combustion engine such that a driving force based on the control force acts on the drive shaft.   The method of controlling a hybrid vehicle according to claim 8, wherein the step of controlling the internal combustion engine increases the direct drive force with a change in an operation point of the internal combustion engine.   In the step of changing the sharing ratio, when the sum of the direct drive force acting on the drive shaft and the drive force generated by the motor does not satisfy the required drive force, an upper limit value of the voltage command value is set. The method for controlling a hybrid vehicle according to claim 8, wherein the control method is changed to the first voltage.

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