JP6019840B2 - Power supply control device and vehicle equipped with the same - Google Patents

Description

  The present invention relates to a control device for a power supply device and a vehicle on which the control device is mounted, and more particularly to power supply control at the time of engine start in a hybrid vehicle including an engine and a rotating electric machine.

  2. Description of the Related Art In recent years, attention has been paid to a vehicle that is mounted with a power storage device (for example, a secondary battery or a capacitor) and travels by driving force generated by a motor using electric power stored in the power storage device as an environment-friendly vehicle. . Such vehicles include, for example, electric vehicles, hybrid vehicles, fuel cell vehicles, and the like.

  Such a vehicle may have a configuration in which a plurality of power storage devices are provided in parallel with a load such as a drive device in order to further extend the travel distance by electric power.

  Japanese Patent Laying-Open No. 2011-199934 (Patent Document 1) is connected in parallel to a first power storage device connected to an inverter that drives a motor generator and a first power storage device via a boost converter with respect to the inverter. An electric vehicle including a power supply device having a second power storage device is disclosed.

  In Japanese Patent Application Laid-Open No. 2011-199934 (Patent Document 1), the electric power from the large-capacity, high-voltage first power storage device and the output voltage from the low-voltage, high-power second power storage device are boosted. The power is appropriately selected according to the required power. In general, since the characteristics of the increase in capacity and output of the power storage device are contradictory, it is difficult to satisfy these two requirements with one type of power storage device. However, by adopting a configuration such as that disclosed in Japanese Patent Application Laid-Open No. 2011-199934 (Patent Document 1), a large capacity can be realized by using both the first power storage device and the second power storage device in normal traveling. When high driving force such as rapid acceleration is required, high output is realized by boosting the output voltage from the second power storage device and supplying it to the inverter. By adopting such a configuration of the power supply device, the entire power supply device can achieve high capacity and high output.

JP 2011-199934 A JP 2007-189829 A JP 2006-121874 A

  In a power supply device configured as in Japanese Patent Application Laid-Open No. 2011-199934 (Patent Document 1), when a first power storage device that does not go through a boost converter is used, a DC voltage supplied to the inverter is used as the first power storage device. It cannot be higher than the output voltage of the device.

  When the above power supply device is applied to a hybrid vehicle equipped with an engine, when the engine is started during so-called EV (Electric Vehicle) traveling that uses only the driving force from the motor generator, the engine is stopped. Driving power for ranking is required. When the cranking torque cannot be achieved when the first power storage device and the second power storage device are used in combination (that is, at a low voltage), the inverter is supplied to the inverter as described above. It is necessary to boost the voltage. However, in this case, since the power of the first power storage device cannot be used, the power that can be supplied from the entire power supply device is limited, and conversely, the driving force for traveling may not be ensured.

  On the other hand, if the voltage supplied to the inverter is not boosted when the engine is started, the EV travelable region may be limited to an operation range in which the cranking torque of the engine can be secured.

  The present invention has been made to solve such a problem, and the object thereof is to have two power storage devices connected in parallel to a load, one of which is connected to the load via a boost converter. In the hybrid vehicle provided with the power supply device, the EV travel range is expanded as much as possible while securing the engine starting torque.

  A control device for a power supply device according to the present invention controls a power supply device that supplies power to a load device of a vehicle. The power supply device includes a first power storage device, a voltage conversion device that converts the voltage of the first power storage device and supplies the voltage to the load device, and a second power storage connected in parallel to the voltage conversion device with respect to the load device Including the device. The load device includes an engine and a first rotating electric machine for starting the engine. When the engine is started, the control device sets the voltage supplied to the load device to a state in which the voltage supplied to the load device is substantially the same as the output voltage of the second power storage device, and the voltage supplied to the load device to the second The second mode in which the voltage is higher than the output voltage of the power storage device is switched based on the state of the vehicle.

  Preferably, the state of the vehicle includes a traveling speed of the vehicle. The control device selects the first mode when the traveling speed falls below a predetermined first reference speed, and selects the second mode when the traveling speed exceeds the first reference speed.

  Preferably, the load device includes a second rotating electrical machine that generates driving force of the vehicle using electric power from at least one of the first and second power storage devices, an engine, and the first and second rotating electrical machines. And a power split mechanism having a planetary gear mechanism. A first rotating electrical machine is coupled to the sun gear of the planetary gear mechanism, a second rotating electrical machine is coupled to the ring gear, and an engine is coupled to the planetary carrier. When the first mode is selected, the control device starts the engine when the driving force required for the second rotating electrical machine exceeds a predetermined threshold determined from the rotational speed of the second rotating electrical machine. To do.

  Preferably, the load device includes a second rotating electrical machine that generates driving force of the vehicle using electric power from at least one of the first and second power storage devices, an engine, and the first and second rotating electrical machines. And a power split mechanism having a planetary gear mechanism. A first rotating electrical machine is coupled to the sun gear of the planetary gear mechanism, a second rotating electrical machine is coupled to the ring gear, and an engine is coupled to the planetary carrier. When the second mode is selected, the control device, when the driving force required for the second rotating electrical machine exceeds a predetermined threshold determined from the rotational speed of the second rotating electrical machine, The engine is started when the rotational speed of the rotating electrical machine exceeds a second reference speed that is greater than the first reference speed.

  Preferably, when the first mode is selected, the control device controls the voltage conversion device, whereby the first ratio of the power output from the first power storage device in the total power supplied to the load device. The second ratio of the electric power output from the second power storage device is controlled. When the first mode is selected, the control device decreases the second rate with time after the start of cranking of the engine, and increases the first rate to compensate for the reduced power.

  Preferably, the control device shifts from the first mode to the second mode in response to the second ratio becoming zero.

  Preferably, the load device includes a second rotating electrical machine that generates driving force of the vehicle using electric power from at least one of the first and second power storage devices, an engine, and the first and second rotating electrical machines. And a power split mechanism having a planetary gear mechanism. A first rotating electrical machine is coupled to the sun gear of the planetary gear mechanism, a second rotating electrical machine is coupled to the ring gear, and an engine is coupled to the planetary carrier. When the first mode is selected, the control device starts the engine when the driving force required for the second rotating electrical machine exceeds a predetermined threshold determined from the rotational speed of the second rotating electrical machine. To do. The control device is predicted that the rotational speed of the first rotating electrical machine required at the time when the power from the second power storage device supplied to the load device is predicted to be zero exceeds the reference rotational speed. In this case, the engine is started before the driving force required for the second rotating electrical machine exceeds the threshold value.

  Preferably, the load device uses a power from at least one of the first and second power storage devices to generate a driving force for the vehicle, and a power for driving the second rotating electrical machine. And a conversion device. The second rotating electrical machine compares the rectangular wave control mode for controlling the voltage phase of the rectangular wave voltage applied to the second rotating electrical machine and the AC voltage command for operating the carrier wave and the second rotating electrical machine. Is controlled by one of the pulse width modulation control modes based on. When starting the engine, the control device preferentially selects a mode operable in the pulse width modulation control mode from the first and second modes.

  A vehicle according to the present invention includes a power supply device, a load device that operates with electric power from the power supply device, and a control device for controlling the power supply device. The power supply device includes a first power storage device, a voltage conversion device that converts the voltage of the first power storage device and supplies the voltage to the load device, and a second power storage connected in parallel to the voltage conversion device with respect to the load device Including the device. The load device includes an engine and a rotating electrical machine for starting the engine. When the engine is started, the control device sets the voltage supplied to the load device to a state in which the voltage supplied to the load device is substantially the same as the output voltage of the second power storage device, and the voltage supplied to the load device to the second The second mode in which the voltage is higher than the output voltage of the power storage device is switched based on the state of the vehicle.

  According to the present invention, in a hybrid vehicle having two power storage devices connected in parallel to a load, one of which is connected to the load via a boost converter, while securing engine starting torque The EV traveling area can be expanded.

1 is an overall block diagram of a hybrid vehicle according to an embodiment. It is a whole block diagram which shows the other example of the hybrid vehicle according to this Embodiment. It is a figure for demonstrating the EV driving | running | working area | region in the case of using together electric power from electrical storage apparatus B1, B2. It is a figure for demonstrating the relationship between a system voltage and an engine cranking torque. It is a figure for demonstrating the relationship between the vehicle speed and the rotational speed of the motor generator 140 at the time of engine starting. It is a figure for demonstrating the EV driving | running | working area | region in the case of making system voltage higher than the output voltage of electrical storage apparatus B2. It is a figure for demonstrating the EV driving | running | working area | region at the time of using the power supply control according to Embodiment 1. FIG. In Embodiment 1, it is a functional block diagram for demonstrating the power supply control performed by ECU. 4 is a flowchart for illustrating a power supply control process executed by an ECU in the first embodiment. It is a figure for demonstrating the time change of the output ratio of an electrical storage apparatus and an engine when not applying the power supply control according to Embodiment 2. FIG. It is a figure for demonstrating the problem when the power supply control according to Embodiment 2 is not applied. It is a figure for demonstrating the time change of the output ratio of an electrical storage apparatus and an engine at the time of applying the power supply control according to Embodiment 2. FIG. In Embodiment 2, it is a flowchart for demonstrating the power supply control process performed by ECU. It is a flowchart for demonstrating the detail of the process of step S170 in FIG. In Embodiment 3, it is a flowchart for demonstrating the power supply control process performed by ECU. It is a flowchart for demonstrating the detail of the process of step S180 in FIG. It is a figure for demonstrating the drive mode of a motor generator. It is a figure for demonstrating the control mode of the motor generator at the time of engine starting in EV drive area | region. In Embodiment 4, it is a figure for demonstrating the engine starting mode in each area | region of FIG. In Embodiment 4, it is a flowchart for demonstrating the engine starting control performed by ECU.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Basic configuration of vehicle]
FIG. 1 is an overall block diagram of hybrid vehicle 100 (hereinafter also simply referred to as “vehicle”) according to the present embodiment.

  Referring to FIG. 1, vehicle 100 includes a power supply device 110, a load device 105, and an ECU 300 (Electronic Control Unit) that is a control device. Power supply device 110 includes power storage devices B1 and B2, a system main relay (SMR) 115, a converter 120 that is a voltage conversion device, capacitors C1 and C2, and a diode D10.

  Load device 105 includes inverters 130 and 135, motor generators 140 and 145, power transmission gear 150, engine 160, drive wheels 170, and rotation angle sensors 190 and 195.

  The power storage devices B1 and B2 are power storage elements configured to be chargeable / dischargeable. The power storage devices B1 and B2 include, for example, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a lead storage battery, and a power storage element such as an electric double layer capacitor.

  Power storage device B1 is connected to converter 120 through power lines PL1, NL1. Electric power from power storage device B1 is boosted to a desired voltage by converter 120 and supplied to load device 105. The power storage device B1 stores the electric power generated by the motor generators 140 and 145. The output of power storage device B1 is, for example, about 200V.

  The power storage device B1 is provided with a voltage sensor and a current sensor (not shown). The voltage sensor detects the voltage of power storage device B1 and outputs detected value VB1 to ECU 300. The current sensor detects a current input / output to / from power storage device B1, and outputs detection value IB1 to ECU 300.

  On the other hand, power storage device B <b> 2 is connected in parallel to converter 120 with respect to load device 105. The positive terminal of power storage device B2 is connected to power line PL2 via diode D10. The negative terminal of power storage device B2 is connected to power line NL1. The power storage device B2 has a higher voltage and a larger capacity than the power storage device B1, and for example, its output voltage is about 400V.

  Diode D10 indicates that current flows from power line PL2 to power storage device B2 when voltage VH between power lines Pl2 and NL1 (hereinafter also referred to as “system voltage”) is set higher than the output voltage of power storage device B2. Provided to prevent. Therefore, if current from power line PL2 to power storage device B2 can be prevented, switch SW10 such as vehicle 100A shown in FIG. 2 can be employed instead of diode D10 in FIG.

  The power storage device B2 is provided with a voltage sensor and a current sensor (not shown). The voltage sensor detects the voltage of power storage device B2, and outputs detected value VB2 to ECU 300. The current sensor detects a current input / output to / from power storage device B2, and outputs detected value IB2 to ECU 300.

  SMR 115 includes a relay connected to the positive terminal of power storage device B1 and power line PL1, and a relay connected to the negative terminal of power storage device B1 and power line NL1. SMR 115 is controlled by control signal SE <b> 1 from ECU 300, and switches between supply and interruption of electric power between power storage device B <b> 1 and load device 105.

  Capacitor C1 is connected between power line PL1 and power line NL1. Capacitor C1 reduces voltage fluctuation between power line PL1 and power line NL1. Voltage sensor 180 detects voltage VL applied to capacitor C1 and outputs the detected value to ECU 300.

  Converter 120 includes switching elements Q1, Q2, diodes D1, D2, and a reactor L1.

  Switching elements Q1 and Q2 are connected in series between power line PL2 and power line NL1, with the direction from power line PL2 toward power line NL1 as the forward direction. In this embodiment, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, a power bipolar transistor, or the like can be used as the switching element.

  Antiparallel diodes D1 and D2 are connected to switching elements Q1 and Q2, respectively. Reactor L1 is provided between a connection node of switching elements Q1 and Q2 and power line PL1. That is, converter 120 forms a step-up / step-down chopper circuit.

  Switching elements Q1, Q2 are controlled by control signal PWC from ECU 300, and perform voltage conversion operation between power line PL1 and power line NL1, and between power line PL2 and power line NL1.

  Converter 120 is basically controlled such that switching elements Q1 and Q2 are turned on and off in a complementary manner in each switching period. Converter 120 boosts DC voltage VL to DC voltage VH during the boosting operation. This boosting operation is performed by supplying the electromagnetic energy accumulated in reactor L1 during the ON period of switching element Q2 to power line PL2 via switching element Q1 and antiparallel diode D1.

  Converter 120 steps down DC voltage VH to DC voltage VL during the step-down operation. This step-down operation is performed by supplying the electromagnetic energy stored in reactor L1 during the ON period of switching element Q1 to power line NL1 via switching element Q2 and antiparallel diode D2.

  The voltage conversion ratio (the ratio of VH and VL) in these step-up and step-down operations is controlled by the on-period ratio (duty ratio) of the switching elements Q1 and Q2 in the switching period. When the step-up operation and the step-down operation are not required (that is, VH = VL), the voltage conversion ratio = 1 by setting the control signal PWC to fix the switching elements Q1 and Q2 to ON and OFF, respectively. 0.0 (duty ratio = 100%).

  When power storage devices B1 and B2 are used in combination, the ratio of the power shared by each power storage device is controlled from the total power supplied to load device 105 by changing the duty ratio. You can also.

  Capacitor C2 is connected between power line PL2 connecting converter 120 and inverters 130 and 135 and power line NL1. Capacitor C2 reduces voltage fluctuation between power line PL2 and power line NL1. Voltage sensor 185 detects voltage VH applied to capacitor C2, and outputs the detected value to ECU 300.

  Inverters 130 and 135 are connected in parallel to converter 120 by power line PL2 and power line NL1. Inverters 130 and 135 are controlled by control commands PWI1 and PWI2 from ECU 300, respectively, and convert DC power output from converter 120 into AC power for driving motor generators 140 and 145, respectively. Inverters 130 and 135 are, for example, three-phase full-bridge type inverters having U-phase, V-phase, and W-phase upper and lower arms.

  Motor generators 140 and 145 are AC rotating electric machines, for example, permanent magnet type synchronous motors having a rotor in which permanent magnets are embedded.

  The output torque of motor generators 140 and 145 is transmitted to drive wheels 170 via power transmission gear 150 constituted by a speed reducer and a power split mechanism, and causes vehicle 100 to travel. Motor generators 140 and 145 are also coupled to engine 160 through power transmission gear 150. Then, ECU 300 operates motor generators 140 and 145 and engine 160 in a coordinated manner to generate a necessary vehicle driving force. Further, motor generators 140 and 145 can generate electric power by rotation of engine 160 or rotation of driving wheel 170, and the generated electric power is converted into charging electric power for power storage device B1 by inverters 130 and 135.

  In the present embodiment, motor generator 145 (hereinafter also referred to as “MG2”) is exclusively used as an electric motor for driving drive wheels 170, and motor generator 140 (hereinafter also referred to as “MG1”) is exclusively used as an engine. The generator is driven by 160. Motor generator 140 is used to crank the crankshaft of engine 160 when engine 160 is started.

  The output shaft of motor generator 140 is coupled to a sun gear of a planetary gear (not shown) included in power transmission gear 150. The output shaft of the motor generator 145 is coupled to the ring gear of the planetary gear, and is also coupled to the drive wheels 170 via the speed reducer. The output shaft of engine 160 is coupled to the planetary carrier of the planetary gear.

  The rotation angle sensors 190 and 195 are provided in the motor generators 140 and 145, respectively. Rotation angle sensors 190 and 195 detect rotation angles θ1 and θ2 of motor generators 140 and 145, respectively, and output the detected values to ECU 300. ECU 300 calculates rotational speeds Nm1, Nm2 or angular speeds of motor generators 140, 145 based on rotational angles θ1, θ2 from rotational angle sensors 190, 195.

  ECU 300 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer, all of which are not shown in FIG. 1, and inputs signals from each sensor and the like, and outputs control signals to each device. 100 and each device are controlled. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  ECU 300 receives detected values of voltages VB1, VB2 and currents IB1, IB2 from power storage devices B1, B2. ECU 300 calculates the state of charge of each of power storage devices B1, B2 (hereinafter also referred to as SOC (State of Charge)) based on these voltages and currents.

  In FIG. 1, a single control device is provided as the ECU 300. However, for example, a control device for the load device 105, a control device for the power storage devices B1 and B2, or the like, a control target device. It is good also as a structure which provides a separate control apparatus for every.

[Embodiment 1]
In the vehicle 100 as described above, EV traveling that uses only the driving force from the motor generator 145 and high output such as acceleration while using mainly the driving force from the engine 160 are performed. It is possible to selectively switch between HV (Hybrid Vehicle) traveling using the driving force from the motor generator 145 as needed.

  In such a hybrid vehicle, from an environmental point of view, such as CO2 and exhaust gas reduction and noise reduction, EV traveling can be applied to a wide range of vehicle conditions as much as possible and continued for a long time. It is desired.

  In a vehicle including two power storage devices as shown in the examples of FIGS. 1 and 2, since the power storage device B2 is directly connected to the load device 105 as described above, output is performed like the power storage device B1. The voltage cannot be boosted. Therefore, when the power storage device B2 is used, it is not suitable for a scene where a high output such as a sudden load change that requires boosting of the system voltage VH is required, but conversely, power conversion by a converter is not involved. Therefore, there is an advantage that a decrease in efficiency is suppressed. By using the power storage device B1 and the power storage device B2 in combination, the power that can be supplied by the entire power supply device can be increased, and long-time power supply is possible. Such combined use of power storage device B1 and power storage device B2 is particularly suitable for traveling in a steady state.

  On the other hand, in a scene where a high output is required, the system voltage VH needs to be boosted, so that the output voltage from power storage device B1 is boosted using converter 120. In this case, the power from power storage device B2 cannot be used, and the power that can be supplied to load device 105 is limited to the power that can be output from power storage device B1.

  That is, when the power storage devices B1 and B2 are used in combination, the power that can be supplied to the load device 105 can be increased (capacity increased), but required when high output is required (for example, at high vehicle speed). The driving force to be exerted cannot be sufficiently exhibited, and the driving force may be insufficient. Conversely, when the output voltage of the power storage device B1 is boosted, a high driving force can be obtained instantaneously (high output), but as a result, the total power that can be supplied to the load device 105 is limited. There is a risk that the driving force of the whole may be insufficient, or the duration of EV travel may be shortened.

  In the configuration of the load device 105 as shown in FIGS. 1 and 2, when the engine 160 is started during EV traveling to ensure driving force and charge the power storage device, the motor generator 140 is used. The cranking of the engine 160 is executed. Further, from the characteristics of the planetary gear included in the power transmission gear 150, during operation of the engine 160, the torque of the motor generator 140 is output so as to receive the engine reaction force.

  Therefore, if the cranking torque of engine 160 by motor generator 140 is insufficient, the engine cannot be started properly. Alternatively, during or after the engine is started, the motor generator 140 may not be able to sufficiently output a reaction force against the engine output torque, and the rotation speed of the motor generator 140 may increase. . If such an engine start is taken into consideration and the appropriate engine start timing is not set in accordance with the travel state of the vehicle, the EV travelable region is excessively narrowed, and EV travel is performed over a wider range of vehicles. There may be cases where the request to continue for a long time cannot be achieved.

  Therefore, in the first embodiment, power supply control is performed so as to expand the EV travelable region as much as possible while considering engine start. Hereinafter, an outline of power supply control according to the first embodiment will be described with reference to FIGS.

  FIG. 3 is a diagram for explaining an EV travel region when electric power from power storage devices B1 and B2 is used in combination. In FIG. 3, the horizontal axis indicates the vehicle speed VS, and the vertical axis indicates the driving force (torque) Tm2 of the motor generator 145. As described in FIG. 1, since the output shaft of motor generator 145 is coupled to drive wheel 170, vehicle speed VS corresponds to the rotational speed of motor generator 145. It should be noted that FIG. 3 is an example of the case where the power storage device and the motor generator have specific characteristics, and may vary depending on the characteristics of the power storage device and the motor generator that are employed.

  With reference to FIG. 1 and FIG. 3, each curve W10-W14 in a figure is demonstrated first. The curves W10 to W14 are the same in the following FIGS.

  Dashed lines W10 and W11 are driving force threshold values determined from the output requirements (power capacity) of the power storage device. Curve W10 shows the threshold value of the driving force that can be output when power storage devices B1 and B2 are used in combination. On the other hand, a curve W11 indicates a threshold value of the driving force that can be output when only the power storage device B1 is used.

  As can be seen from the curves W10 and W11, the power range that can be supplied to the motor generator is larger when the power storage devices B1 and B2 are used together than when only the power storage device B1 is used.

  Solid curve lines W12 and W14 are threshold values of the driving force determined from the characteristics of the motor generator 145. The curves W12 and W14 do not take into account the limitation of the power capacity that can be supplied by the power storage device.

  A curve W12 indicates a threshold value of the driving force that can be output by the motor generator 145 when the system voltage VH is a maximum voltage that can be set. On the other hand, curve W14 indicates a threshold value of the driving force that can be output by motor generator 145 when the system voltage is the output voltage of power storage device B2. The threshold value of the driving force is determined mainly by the driving force limitation based on the current flowing through the motor generator or the inverter that drives the motor generator. Therefore, the higher the applied voltage, the greater the driving force that can be output.

  Curve W13 is a threshold value determined by whether or not engine cranking torque can be secured by motor generator 140 when engine 160 is started. As shown in FIG. 4, the motor generator 140 also has a characteristic that the torque that can be output decreases as the rotational speed increases, as with the curves W12 and W14 of the motor generator 145 in FIG. Curves L10 and L11 in FIG. As the system voltage VH increases, the driving force that can be output at the same rotational speed tends to increase. Therefore, for example, if the engine cranking torque is line L15 in FIG. 4, and if system voltage VH is the output voltage of power storage device B2, rotation speed Nm1 of motor generator 140 exceeds N1. Engine cranking torque cannot be secured. On the other hand, when the system voltage VH is the maximum usable voltage, the engine cranking torque can be secured until the rotational speed Nm1 becomes N2 (> N1).

  Note that when the engine 160 is started during traveling, the motor generator 140 is negatively rotated as shown in the collinear diagram of FIG. 5, so when cranking the engine and increasing the rotational speed, A power generation state occurs due to positive torque and negative rotation. Also in this case, the torque generated by motor generator 140 is limited by system voltage VH. That is, if the system voltage VH is lowered, the power generated by the motor generator 140 is limited, so that the torque generated by the motor generator 140 is also limited.

  Further, as can be seen from the alignment chart shown in FIG. 5, during EV traveling (when the engine is stopped), if the vehicle speed, that is, the magnitude (absolute value) of the rotational speed Nm2 of the motor generator 145 increases, the motor generator 140 The magnitude (absolute value) of the rotational speed Nm1 also increases. Therefore, in order to ensure engine cranking torque at a relatively high vehicle speed, it is necessary to set system voltage VH high.

  Therefore, referring again to FIG. 3, when system voltage VH is the output voltage of power storage device B2, engine 160 cannot be secured when vehicle speed V1 corresponding to rotational speed N1 in FIG. Can not start. When system voltage VH is the maximum boosted voltage, engine 160 cannot be started when vehicle speed V2 corresponding to rotational speed N2 in FIG. 4 is exceeded.

  Considering these conditions, when the power storage devices B1 and B2 are used in combination, the hatched area in FIG. 3 is determined as the EV travelable area. That is, regarding the vehicle speed, the EV travelable region is limited to a region where the engine cranking torque that can be generated by the motor generator 140 is lower than the vehicle speed V1 that is limited by the system voltage VH determined by the output voltage of the power storage device B2. . As for the driving force, the output is limited by the power storage devices B1 and B2 (curve W10 in FIG. 3) and the driving force is limited by the system voltage VH determined by the output voltage of the power storage device B2 (curve W14 in FIG. 3). The EV travelable area is limited to an area where the smaller driving force is obtained.

  On the other hand, when boosting the output voltage of power storage device B1, the hatched area in FIG. 6 is determined as the EV travelable area. That is, regarding the vehicle speed, the EV travelable region is limited to a region lower than the vehicle speed V2 limited by the engine cranking torque at the maximum boosted voltage of the system voltage VH. Regarding the driving force, the EV travelable region is limited by the output limit (curve W11 in FIG. 6) by the power storage device B1.

  As can be seen from FIGS. 3 and 6, in the region where the vehicle speed VS is lower than the vehicle speed V1, the combined use of the power storage devices B1 and B2 can provide a wider EV travelable region than the system voltage VH is boosted. it can. Further, in a region where the vehicle speed VS is higher than the vehicle speed V1 and lower than the vehicle speed V2, that is, in a region where the vehicle speed is relatively high, the system voltage VH is set to a voltage higher than the output voltage of the power storage device B2, so Can be implemented.

  Therefore, in the power supply control in the first embodiment, the region in which FIG. 3 and FIG. 6 are combined (the hatched region in FIG. 7) is the EV travelable region, and the vehicle travel state, that is, the motor generator 145 drive state Accordingly, the case where the power storage devices B1 and B2 are used together is switched between the case where only the power storage device B1 is used with the system voltage VH set to a voltage higher than the output voltage of the power storage device B2.

  As a result, a wide EV travelable region can be obtained while securing the cranking torque of the engine.

  FIG. 8 is a functional block diagram for illustrating power supply control executed by ECU 300 in the first embodiment. Each functional block described in the functional block diagram illustrated in FIG. 8 is realized by hardware or software processing by the ECU 300.

  Referring to FIGS. 1 and 8, ECU 300 includes a determination unit 310, a storage unit 320, a converter control unit 330, an inverter control unit 340, and an engine control unit 350.

  Determination unit 310 receives respective required driving forces Tm1, Tm2 and rotational speeds Nm1, Nm2 for motor generators 140, 145. Determination unit 310 also receives engine speed Ne.

  Based on this information and the threshold map MAP as shown in FIG. 7 stored in advance in storage unit 320, determination unit 310 determines whether or not EV travel can be performed, and determines power storage devices B1 and B2. It is determined whether to use them together, or to boost system voltage VH higher than the output voltage of power storage device B2 to use only power storage device B1. When power storage devices B1 and B2 are used in combination, the ratio of the power shared by each power storage device in the total power supplied to load device 105 is also determined. Further, the determination unit 310 is configured such that when the state of the motor generator 145 is outside the EV travelable region in FIG. 7 or when the power supplied from the power storage device becomes insufficient due to the operation of an auxiliary device (not shown). It is also determined whether or not the engine 160 needs to be started.

  Then, determination unit 310 outputs signal INF including the above information to converter control unit 330, inverter control unit 340, and engine control unit 350.

  Converter control unit 330 receives signal INF from determination unit 310. Converter control unit 330 generates control signal PWC for converter 120 based on signal INF, and controls converter 120 using control signal PWC.

  Inverter control unit 340 receives signal INF from determination unit 310. Then, inverter control unit 340 generates control signals PWI1 and PWI2 for inverters 130 and 135 based on this signal INF, respectively. The inverter control unit 340 controls the inverters 130 and 135 using these control signals PWI1 and PWI2.

  Engine control unit 350 receives signal INF from determination unit 310. Then, engine control unit 350 generates control signal DRV for driving engine 160 based on this signal INF. Engine control unit 350 controls engine 160 using control signal DRV.

  FIG. 9 is a flowchart for illustrating a power supply control process executed by ECU 300 in the first embodiment. The processing of the flowcharts shown in FIG. 9 and FIGS. 13 to 16 and FIG. 20 described below is realized by a program stored in advance in the ECU 300 being called from the main routine and executed in a predetermined cycle. . Alternatively, the processing of some steps can be realized by constructing dedicated hardware (electronic circuit).

  Referring to FIGS. 1 and 9, ECU 300 determines in step (hereinafter abbreviated as “S”) 100 whether vehicle 100 is currently performing EV travel.

  If the vehicle is not traveling in EV (NO in S100), this control is not necessary, and the subsequent processing is skipped and the processing returns to the main routine.

  If EV traveling is being performed (YES in S100), the process proceeds to S110, and ECU 300 obtains threshold map MAP as shown in FIG. In addition, ECU 300 acquires the current torque and rotational speed (or vehicle speed) of motor generator 145 (S120).

  Thereafter, in S130, ECU 300 determines whether or not current vehicle speed VS is greater than threshold value α corresponding to vehicle speed V1 shown in FIG.

  If vehicle speed VS is equal to or lower than threshold value α (NO in S130), the process proceeds to S140, and ECU 300 sets a mode in which system voltage VH is set as the output voltage of power storage device B2. That is, the mode in which the power storage devices B1 and B2 are used together is selected.

  In step S150, ECU 300 determines whether engine 160 needs to be driven. Specifically, the required torque for the motor generator 145 exceeds the threshold value shown in FIG. 7 by the accelerator operation of the user, or more electric power is required due to the operation of the auxiliary device or the like. It is determined whether or not.

  If it is necessary to drive engine 160 (YES in S150), the process proceeds to S160, and ECU 300 selects HV travel mode and starts engine 160.

  If drive of engine 160 is not necessary (NO in S150), the process proceeds to S190, and ECU 300 selects the EV travel mode and continues EV travel.

  On the other hand, if the vehicle speed is greater than threshold value α in S130 (YES in S130), the process proceeds to S200, and ECU 300 sets the mode in which system voltage VH is higher than the output voltage of power storage device B2. . That is, in this case, only the power storage device B1 is used.

  In step S210, the ECU 300 determines whether the engine 160 needs to be driven. Specifically, whether or not the vehicle speed is further increased and is larger than a threshold value β indicating the vehicle speed V2 shown in FIG. 7, whether the required torque to the motor generator 145 is the threshold value shown in FIG. It is determined whether or not more electric power is required by operating the auxiliary device or the like.

  If drive of engine 160 is necessary (YES in S210), the process proceeds to S220, and ECU 300 selects HV travel mode and starts engine 160.

  If drive of engine 160 is not necessary (NO in S210), the process proceeds to S230, and ECU 300 selects the EV travel mode and continues EV travel.

  By performing control according to the above-described processing and appropriately setting the system voltage according to the traveling state of the vehicle, it is possible to perform EV traveling in the widest possible traveling state while ensuring the engine driving torque.

[Embodiment 2]
In Embodiment 1, when engine 160 is started while power storage devices B1 and B2 are used together, basically, the output from engine 160 is preferentially used. That is, as the output of engine 160 increases, the outputs of power storage devices B1 and B2 decrease.

  FIG. 10 schematically shows such a state, and shows temporal changes in the outputs of power storage devices B1 and B2 and engine 160.

  Referring to FIG. 10, when the requested output from the user is small (until time t10), the output from power storage device B2 that does not require boosting by converter 120 is used from the viewpoint of efficiency.

  When the user request output increases and exceeds the output possible power of power storage device B2, power from power storage device B1 is additionally output at the output voltage boosted to the voltage of power storage device B2 by converter 120.

  Thereafter, when the user request output further increases, cranking of engine 160 is started at time t11 before the maximum output using power storage devices B1 and B2 is obtained in order to obtain the output from engine 160. Then, as engine 160 starts at time t12 and the output from engine 160 increases, the outputs from power storage devices B1 and B2 are gradually reduced.

  At time t13, after the output from power storage devices B1 and B2 disappears and is replaced with the output from engine 160, if further output is required due to rapid acceleration or the like, converter 120 sets system voltage VH to While boosting, the output from the power storage device B1 is added.

  As shown in FIG. 10, when the output from the power storage device is reduced, if the power storage devices B1 and B2 are reduced at the same rate, the output from the power storage device B2 is continued until time t13. Therefore, it is necessary to maintain system voltage VH at the output voltage of power storage device B2.

  However, as shown in FIG. 11, after engine 160 is started, if the rotational speed of engine 160 increases, the torque of motor generator 140 required as a reaction force increases. Further, as described with reference to FIG. 4, the output torque is limited when the rotation speed increases. In this case, as described above, if system voltage VH is set low, the torque that can be generated by motor generator 140 is limited, and a sufficient reaction force cannot be generated, and the rotation speed of motor generator 140 is reduced. It may increase.

  In order to avoid this, it is necessary to set the system voltage VH higher, but if the system voltage VH is boosted when the output ratio from the power storage device B2 is not zero, the output from the power storage device B2 is increased. There is a risk that the torque output is suddenly stopped, and the total output by the power storage device and the engine is instantaneously reduced to cause a torque shock.

  On the other hand, if the boosting of the system voltage VH is delayed until the output ratio from the power storage device B2 becomes zero, the response to the user's requested output may be delayed and drivability may be deteriorated.

  Therefore, in the second embodiment, as shown in FIG. 12, in response to the start of cranking of engine 160, the output ratio of power storage devices B1 and B2 is changed and the output from power storage device B2 is changed. The output distribution ratio changing control is executed so as to finish the process as soon as possible. More specifically, when cranking of engine 160 is started, the output from power storage device B2 is reduced with time, and the output of power storage device B1 is increased so as to compensate for the reduced output.

  As a result, as shown at time t23 in FIG. 12, the output from the power storage device B2 ends before all of the requested output is replaced with the output from the engine 160. In other words, in this state, since the output from the power storage device is only the output from power storage device B1, the system voltage VH can be boosted after time t23.

  As a result, before the required output is replaced with the output from engine 160, if more output is required due to rapid acceleration or the like, the output from power storage device B1 can be used quickly. Thereby, generation | occurrence | production of the torque shock and deterioration of drivability by rapid output fall can be suppressed.

  FIG. 13 is a flowchart for illustrating a power supply control process executed by the ECU in the second embodiment. FIG. 13 is obtained by adding step S170 to the flowchart of FIG. 9 in the first embodiment. FIG. 14 is a flowchart showing detailed processing of step S170 of FIG. In FIG. 13, the description of the same steps as those in FIG. 9 will not be repeated.

  Referring to FIG. 13, using threshold map MAP acquired in S110, a mode in which power storage devices B1 and B2 are used together is selected (NO in S130), and engine 160 needs to be started. If determined (YES in S150), HV traveling is selected in S160, and the engine is started.

  Then, in S170, ECU 300 executes the output distribution ratio changing process for power storage devices B1 and B2 as described in FIG.

  Specifically, referring to FIG. 14, in response to the start of cranking of engine 160, ECU 300 increases the output from power storage device B1 in S171, and from power storage device B2. Reduce output.

  In step S172, ECU 300 determines whether or not the distribution rate of power storage device B2 is 0%.

  If the distribution rate of power storage device B2 is not 0% (NO in S172), the process returns to S170, and ECU 300 further decreases the output distribution rate of power storage device B2.

  On the other hand, when the distribution ratio of power storage device B2 becomes 0% (YES in S172), the process proceeds to S174, and ECU 300 performs boost control of system voltage VH in order to cope with a rapid output increase. To start.

  By controlling according to the processing as described above, the system voltage VH can be boosted early even when the output increase is required immediately after starting the engine with the power storage devices B1 and B2 used together. It is possible to increase the required output while maintaining comfortable drivability.

[Embodiment 3]
In the second embodiment, the output from power storage device B2 is terminated as soon as possible by changing the output distribution ratio of power storage devices B1 and B2 so that the increase in driving force after engine cranking can be quickly handled. The configuration in which the voltage VH can be boosted has been described.

  During and after startup of engine 160 when power storage devices B1 and B2 are used in combination, the rotational speed of motor generator 140 increases as the rotational speed of engine 160 increases. As described with reference to FIG. 4, the output torque of motor generator 140 tends to decrease as the rotational speed increases. Therefore, depending on the state of the vehicle, cranking torque may be insufficient during engine cranking, or the engine reaction force may not be sufficiently supported by motor generator 140 after engine startup.

  Therefore, in Embodiment 3, when the output distribution ratio change control of power storage devices B1 and B2 described in Embodiment 2 is performed, the output of power storage device B2 is stopped (distribution rate = 0%). Control for changing the cranking timing of the engine is performed depending on whether or not the state of the motor generator 140 can be realized.

  More specifically, the required driving force when the maximum accelerator opening is set at the current vehicle speed during EV traveling is predicted, and the engine 160 is driven to output the power storage device B2 in the output distribution ratio change control. The rotation speed and required output torque of the motor generator 140 when it is assumed that the motor has been stopped are predicted. Then, it is determined whether or not the state can be realized from the characteristics of the system voltage VH and the motor generator 140, and when it is predicted that the state cannot be realized, it is necessary to drive the engine 160 from the required driving force. Even in a state where it is not performed, driving of the engine 160 is started in advance.

  Next, FIG. 15 and FIG. 16 are flowcharts for illustrating a power supply control process executed by ECU 300 in the third embodiment. FIG. 15 is obtained by adding step S180 to the flowchart of FIG. 13 described in the second embodiment. FIG. 16 is a flowchart for explaining details of step S180 in FIG. In FIG. 15, description of elements overlapping with FIG. 13 will not be repeated.

  First, referring to FIG. 15, when a mode in which power storage devices B1 and B2 are used in combination is selected using threshold map MAP acquired in S110 (NO in S130), ECU 300 in S150, Whether the engine 160 needs to be started is stabilized based on the current required driving force and the like.

  If it is determined that engine 160 needs to be driven (YES in S150), the process proceeds to S160, and ECU 300 selects HV traveling and starts engine 160 as described in the second embodiment. The distribution rate changing process for the power storage devices B1 and B2 is executed.

  If it is determined that driving of engine 160 is not necessary (NO in S150), the process proceeds to S180, and ECU 300 executes a torque shortage prediction process for motor generator 140.

  If it is predicted that torque shortage of motor generator 140 will not occur, the process proceeds to S190 and EV travel is continued. On the other hand, when it is predicted that torque shortage of motor generator 140 will occur, the process proceeds to S160, HV traveling is selected, and engine 160 is started.

  Next, details of the torque shortage prediction process of the motor generator 140 in S180 will be described with reference to FIG.

  Referring to FIG. 16, when the process proceeds to S180, first, in S181, ECU 300 starts engine 160 and completes changing the output distribution ratio of power storage devices B1 and B2 (that is, power storage device B2 Estimate the time T1 (when the distribution rate is 0%). This estimation is calculated as follows.

  When the current vehicle request output is Pv, the rate of increase of the vehicle request output when the accelerator opening is 100% is ΔPv, and the time from cranking the engine 160 to starting is T0, the change of the output distribution ratio is complete The vehicle output at this time can be expressed as Pv + ΔPv · (T0 + T1). Here, the increase rate ΔPv of the vehicle required output can be acquired using a predetermined fixed value or a predetermined map.

  Then, at the limit at which torque shortage of motor generator 140 does not occur, this output corresponds to the sum of the maximum output (Pb1_max) of power storage device B1 and the output of engine 160, so the relationship of the following equation (1) is established. To do.

Pv + ΔPv · (T0 + T1) = Pb1_max + ΔPe · T1 (1)
Here, ΔPe is an output increase rate after the engine 160 is started.

When this equation (1) is transformed, the time T1 is calculated by the following equation (2).
T1 = (Pv + ΔPv · T0−Pb1_max) / (ΔPe−ΔPv) (2)
As described above, when time T1 is calculated in S180, ECU 300 predicts output Pe of engine 160 at time T1 by the following equation (3) in S182.

Pe = ΔPe · T1 (3)
In step S182, ECU 300 predicts engine 160 rotation speed Ne from engine output Pe calculated and the characteristics of engine 160 determined in advance through experiments or the like.

  In step S183, the ECU 300 uses the current vehicle speed V and the acceleration a when the accelerator opening degree is 100% in consideration of the slope of the traveling road to calculate the vehicle speed Vs when the distribution ratio change is completed as follows. Predict by equation (4).

VS = V + a · (T0 + T1) (4)
In S184, ECU 300 predicts rotation speed Nm2 and output torque Tm2 of motor generator 145 when the distribution ratio change is completed from vehicle speed VS predicted in this way.

  Then, in S185, ECU 300 uses the alignment chart to calculate the distribution ratio change from the torque Tm2 and rotation speed Nm2 of motor generator 145 and the engine torque obtained from rotation speed Ne and output Pe of engine 160. The output torque Tm1 and the rotational speed Nm1 required for the motor generator 140 are predicted.

  After that, ECU 300, in S186, from the map indicating the characteristics of motor generator 140, reference rotation for realizing required torque Tm1 of motor generator 140 predicted above when system voltage VH is the output voltage of power storage device B2 is performed. The speed Nref1 is calculated. Then, it is determined whether or not the predicted rotational speed Nm1 exceeds the reference rotational speed Nref1 (S187).

  If predicted rotation speed Nm1 exceeds reference rotation speed Nref1 (YES in S187), ECU 300 determines that the engine reaction force cannot be countered by the output torque of motor generator 140 when the distribution ratio change is completed, and the process proceeds to S160. The engine 160 is started in advance.

  On the other hand, when predicted rotation speed Nm1 is equal to or lower than reference rotation speed Nref1 (NO in S187), ECU 300 determines that the engine reaction force can be countered by the output torque of motor generator 140, advances the process to S190, and runs EV. Continue.

  By performing control according to the above processing, it is possible to prevent insufficient driving force and deterioration of drivability due to insufficient torque of the motor generator when the output distribution ratio change is completed.

[Embodiment 4]
As described above, the motor generator is driven by using an inverter, and this inverter is generally controlled in either a pulse width modulation (PWM) control mode or a rectangular wave voltage control mode. Can do.

  FIG. 17 is a diagram schematically illustrating the control mode of the motor generator. As shown in FIG. 17, power conversion in the inverter is used by switching three control methods of sine wave PWM control, overmodulation PWM control, and rectangular wave control.

  The sine wave PWM control is used as a general PWM control, and controls on / off of each phase upper and lower arm elements according to a voltage comparison between a sine wave voltage command and a carrier wave (typically a triangular wave). . As a result, for a set of a high level period corresponding to the on period of the upper arm element and a low level period corresponding to the on period of the lower arm element, the duty is set so that the fundamental wave component becomes a sine wave within a certain period. Is controlled. In sine wave PWM control, asynchronous PWM control is applied, and the carrier frequency of the carrier wave is set regardless of the rotational speed of the motor generator. The carrier frequency in the sine wave PWM control is set in a range (for example, about 5 to 10 kHz) that is higher than the audible frequency band and in which the switching loss is not excessive.

  Switching between sinusoidal PWM control and overmodulation PWM control is expressed by a ratio of a fundamental component (effective value) of a motor applied voltage (line voltage) to a DC link voltage (that is, system voltage VH) of an inverter. Rate ". Specifically, when the modulation rate is equal to or lower than the predetermined upper limit value UL, the sine wave PWM control is selected, and when the modulation rate exceeds the upper limit value UL, the overmodulation PWM control is selected.

  In this specification, this modulation factor is obtained when the voltage command value obtained by three-phase to two-phase conversion (dq axis conversion) is set to Vd and Vq for the voltage command applied to the motor generator. It can be expressed by the following equation (5).

Modulation rate = (Vd ² + Vq ² ) ^1/2 / VH (5)
In the sine wave PWM control, typically, the amplitude of the voltage command of the sine wave is set to be in a range equal to or lower than the carrier wave amplitude, and in this case, the upper limit value UL is set to about 0.61. Also proposed is a control method in which a voltage command is generated by superimposing a 3n-order harmonic component (n: a natural number, typically n = 1 third-harmonic) on a sine wave component in the range below the carrier wave amplitude. In this case, the upper limit value UL is set to about 0.71, for example. In the present specification, even when the amplitude of the sine wave voltage command is larger than the carrier wave amplitude, the case where asynchronous PWM control is performed is referred to as sine wave PWM control.

  On the other hand, in the rectangular wave voltage control, one pulse of a rectangular wave having a ratio of 1: 1 between the high level period and the low level period is applied to the AC motor within the predetermined period. As a result, the modulation rate is increased to 0.78.

  Overmodulation PWM control is used at a modulation factor between sinusoidal PWM control and rectangular wave voltage control. In overmodulation PWM control, synchronous PWM control is applied, and the carrier frequency of the carrier wave is controlled in accordance with the rotational speed of motor generator 140. That is, the carrier wave synchronized with the phase of the voltage command is such that the carrier frequency is an integral multiple of the frequency of the voltage command according to the rotation speed of the motor generator (preferably 3 · (2n−1) times, n: natural number). Generated.

  In general, overmodulation PWM control performs PWM control similar to the sine wave PWM control in a range where the amplitude of the voltage command (sine wave component) is larger than the carrier wave amplitude. The fundamental wave component can be increased by distorting the voltage command from the original sine wave waveform (amplitude correction), and the modulation rate can be increased from the maximum modulation rate UL in the sine wave PWM control mode to a range of 0.78. it can. In overmodulation PWM control, the voltage command (sinusoidal component) has a larger amplitude than the carrier wave amplitude, so the line voltage applied to the motor generator is not a sine wave but a distorted voltage.

  In the PWM control mode, control is performed by feeding back the current of the motor generator, so that the motor generator can be controlled with a relatively high response. On the other hand, in the rectangular wave control mode, since the phase of the voltage is controlled, it is known that the response is slightly inferior to the PWM control mode.

  Generally, when the engine is started, vibration occurs during cranking. In the configuration of the hybrid vehicle of the present embodiment, the engine and the motor generator are coupled by the planetary gear of the power transmission gear, so that vibration at the time of starting the engine is easily transmitted to the drive wheels.

  On the other hand, there is a case where a technique of canceling such vibration generated at the time of starting the engine by control of a motor generator may be employed. However, in this case, if the motor generator is not controlled with good response to the vibration from the engine, the vibration cannot be canceled appropriately, and the vibration may be promoted.

  As described above, the PWM control mode and the rectangular wave control mode are used for the drive control of the motor generator. However, since the rectangular wave control mode is inferior to the PWM control mode as described above, the engine There is a possibility that it cannot respond appropriately to the vibration at the start.

  As described above, the control mode of the motor generator is basically switched according to the modulation rate. The modulation factor changes depending on the system voltage VH, and the rectangular wave control mode is easily selected as the system voltage VH is lower.

  Therefore, in the fourth embodiment, when starting the engine during EV traveling, power control is performed to switch the power storage device used for power supply so that a PWM control mode with good responsiveness is preferentially selected.

  FIG. 18 is a diagram for explaining a control mode of the motor generator when starting the engine in the EV traveling region. In FIG. 18, two curves W20 and W21 are further added to FIG. 7 described in the first embodiment.

  Referring to FIG. 18, curve W20 shows a threshold value for switching between the PWM control mode and the rectangular wave control mode when system voltage VH is the output voltage of power storage device B2. Then, the PWM control mode is selected in a region where the vehicle speed VS and the driving force Tm2 are lower than the curve W20 (that is, the left side of the curve W20 in FIG. 18).

  On the other hand, a curve W21 indicates a threshold value for switching between the PWM control mode and the rectangular wave control mode when the system voltage VH is set to the maximum voltage that can be boosted. Therefore, in the region between curve W20 and curve W21, the PWM control mode can be selected by setting system voltage VH higher than the output voltage of power storage device B2. Further, on the high speed side or the high driving force side from the curve W21 (that is, the right side from the curve W21 in FIG. 18), the drive in the PWM control mode cannot be performed and the rectangular wave control mode is adopted.

  In the fourth embodiment, the EV travelable area is divided into six areas by the curves W10, W11, W13, W14, W20, and W21.

  18 and 19, the description of each region and the engine start mode in each region will be described.

  Referring to FIGS. 18 and 19, region I uses system voltage VH as the output voltage of power storage device B <b> 2 to supply power using power storage devices B <b> 1 and B <b> 2 together (hereinafter also referred to as “Case A”). The PWM control mode can be selected both when the system voltage VH is set higher than the output voltage of the power storage device B2 and power is supplied only by the power storage device B1 (hereinafter also referred to as “case B”). This is an important area.

  In this region I, either the case A or the case B can be adopted for canceling the vibration at the time of starting the engine, but it is more preferable to adopt the case A from the viewpoint of increasing the capacity.

  Region II is a rectangular wave control mode in case A, but in case B, PWM control mode can be selected by appropriately setting system voltage VH. Therefore, in the fourth embodiment, Case B is adopted in this region II.

  In the region III and the region IV, the output is insufficient with only the power storage device B1, and therefore the case A is basically adopted. However, PWM control mode is employed in region III, but rectangular wave control mode is employed in region IV because system voltage VH is the output voltage of power storage device B2.

  For region V, both case A and case B can be selected. In either case, the motor generator is controlled in the rectangular wave control mode. Therefore, in the case of the region V, as in the case of the region I, it is preferable to adopt the case A from the viewpoint of increasing the capacity.

  Area VI is an area in which only case B can be selected. In this area, the rectangular wave control mode is employed.

  As can be seen from these, in comparison with the case of the first embodiment, the case B is adopted in the case of the range of the region II in the fourth embodiment.

  Note that when the engine is started in such a region, the motor generator 145 is used, for example, to secure the driving force of an auxiliary device such as an air conditioner, to protect the power storage device or the motor generator, or to increase the gradient. This is a case where the driving force by the engine 160 is required, though the state of FIG.

  FIG. 20 is a flowchart for illustrating engine start control executed by ECU 300 in the fourth embodiment.

  Referring to FIG. 20, ECU 300 determines in S300 whether the vehicle is currently traveling on EV.

  If the vehicle is not in EV travel (NO in S300), the control is unnecessary, and ECU 300 skips the subsequent processing and ends the processing. If EV traveling is in progress (YES in S300), the process proceeds to S310, and ECU 300 determines whether or not a request for starting engine 160 has been made.

  If there is no engine start request (NO in S310), ECU 300 skips the subsequent processing and ends the processing. If there is an engine start request (YES in S310), the process proceeds to S320, and ECU 300 obtains threshold map MAP as shown in FIG. 18 from the storage unit.

  In S330, ECU 300 detects the current torque and rotational speed (vehicle speed) of motor generator 145, and sets the control mode of motor generator 145 at the time of engine start based on the detected value and threshold map MAP. Select (S340).

  Thereafter, ECU 300 starts engine 160 in S350 using the control mode selected in S340.

  By performing control according to the above-described process, in a hybrid vehicle including a high-voltage power storage device and a low-voltage power storage device via a converter, EV travel is performed in as wide a range of travel as possible while securing engine drive torque. In addition, it is possible to reduce vibrations that occur when starting the engine during EV traveling.

  It should be noted that the threshold values shown in FIGS. 3, 6, 7 and 18 are actually preferably provided with a slight margin and hysteresis in consideration of chattering and response delay in control.

  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.

  100 vehicle, 105 load device, 110 power supply device, 115 SMR, 120 converter, 130, 135 inverter, 140, 145 motor generator, 150 power transmission gear, 160 engine, 170 driving wheel, 180, 185 voltage sensor, 190, 195 rotation Angle sensor, 300 ECU, 310 determination unit, 320 storage unit, 330 converter control unit, 340 inverter control unit, 350 engine control unit, B1, B2 power storage device, C1, C2 capacitor, D1, D2, D10 diode, L1 reactor, NL1, PL1, PL2 Power line, Q1, Q2 switching element, SW10 switch.

Claims (9)

A control device for controlling a power supply device that supplies power to a load device of a vehicle,
The power supply device
A first power storage device;
A voltage converter that converts the voltage of the first power storage device and supplies the converted voltage to the load device;
A second power storage device connected in parallel to the voltage converter with respect to the load device,
The load device is:
Engine,
A first rotating electrical machine for starting the engine,
The control device includes: a first mode in which a voltage supplied to the load device is approximately equal to an output voltage of the second power storage device; and a voltage supplied to the load device in the second power storage. A second mode in which the voltage is higher than the output voltage of the device is switched based on the state of the vehicle, and in the first mode, the first rotating electrical machine provides a torque required for starting the engine. A control device for a power supply device that selects the second mode when it cannot be generated. The state of the vehicle includes a traveling speed of the vehicle,
When the traveling speed of the vehicle exceeds a predetermined first reference speed, the first rotating electrical machine cannot generate torque necessary for starting the engine,
The control device selects the first mode when the travel speed is lower than the first reference speed, and selects the second mode when the travel speed is higher than the first reference speed. The control device of the power supply device according to claim 1 to select. The load device includes a second rotating electrical machine that generates driving force of the vehicle using electric power from at least one of the first and second power storage devices;
A power split mechanism coupled to the engine and the first and second rotating electric machines and having a planetary gear mechanism;
The first rotating electrical machine is coupled to the sun gear of the planetary gear mechanism, the second rotating electrical machine is coupled to the ring gear, and the engine is coupled to the planetary carrier,
The control device, when the first mode is selected, when the driving force required for the second rotating electrical machine exceeds a predetermined threshold determined from the rotational speed of the second rotating electrical machine The control device for a power supply device according to claim 2, wherein the engine is started. The load device includes a second rotating electrical machine that generates driving force of the vehicle using electric power from at least one of the first and second power storage devices;
A power split mechanism coupled to the engine and the first and second rotating electric machines and having a planetary gear mechanism;
The first rotating electrical machine is coupled to the sun gear of the planetary gear mechanism, the second rotating electrical machine is coupled to the ring gear, and the engine is coupled to the planetary carrier,
The control device, when the second mode is selected, when the driving force required for the second rotating electrical machine exceeds a predetermined threshold determined from the rotational speed of the second rotating electrical machine, Alternatively, the control device of the power supply apparatus according to claim 2, wherein the engine is started when a rotation speed of the second rotating electrical machine exceeds a second reference speed that is larger than the first reference speed. When the first mode is selected, the control device controls the voltage conversion device to control the first power output from the first power storage device in the total power supplied to the load device. And a second ratio of power output from the second power storage device,
When the first mode is selected, the control device reduces the second ratio with time after the start of cranking of the engine, and reduces the reduced power output from the second power storage device. The control apparatus for a power supply apparatus according to claim 2, wherein the first ratio is increased to compensate.   The control device for a power supply device according to claim 5, wherein the control device shifts from the first mode to the second mode in response to the second ratio becoming zero. The load device includes a second rotating electrical machine that generates driving force of the vehicle using electric power from at least one of the first and second power storage devices;
A power split mechanism coupled to the engine and the first and second rotating electric machines and having a planetary gear mechanism;
The first rotating electrical machine is coupled to the sun gear of the planetary gear mechanism, the second rotating electrical machine is coupled to the ring gear, and the engine is coupled to the planetary carrier,
The control device, when the first mode is selected, when the driving force required for the second rotating electrical machine exceeds a predetermined threshold determined from the rotational speed of the second rotating electrical machine To start the engine,
In the control device, the rotation speed of the first rotating electrical machine required at a time when the electric power from the second power storage device supplied to the load device is predicted to be zero exceeds the reference rotation speed. The control device for the power supply device according to claim 6, wherein the engine is started before a driving force required for the second rotating electric machine exceeds the threshold value. Before Symbol load device,
A second rotary electric machine for generating a driving force of the vehicle using at least from one of the power before Symbol first and second power storage devices,
Further comprising a power converter for driving the second rotating electric machine,
The second rotating electrical machine includes a rectangular wave control mode for controlling a voltage phase of a rectangular wave voltage applied to the second rotating electrical machine, and an AC voltage command for operating a carrier wave and the second rotating electrical machine. Controlled by one of the pulse width modulation control modes based on comparison with
2. The power supply device according to claim 1 , wherein when the engine is started, the control device preferentially selects a mode operable in the pulse width modulation control mode from the first and second modes. Control device. A vehicle,
A power supply;
A load device that operates with electric power from the power supply device;
A control device for controlling the power supply device,
The power supply device
A first power storage device;
A voltage converter that converts the voltage of the first power storage device and supplies the converted voltage to the load device;
A second power storage device connected in parallel to the voltage converter with respect to the load device,
The load device is:
Engine,
A rotating electrical machine for starting the engine,
The control device includes: a first mode in which a voltage supplied to the load device is approximately equal to an output voltage of the second power storage device; and a voltage supplied to the load device in the second power storage. When the second mode in which the voltage is higher than the output voltage of the apparatus is switched based on the state of the vehicle, and in the first mode, the rotating electrical machine cannot generate torque necessary for starting the engine. And selecting the second mode.

Images