JP6701861B2 - Hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle, and more specifically, to a hybrid vehicle having a traveling mode in which an in-vehicle power storage device is not used.

  In JP2012-153220A (Patent Document 1) and JP2013-60042A (Patent Document 2), first and second motor generators are connected via a common DC voltage wiring and an inverter. In the configuration of the hybrid vehicle described above, traveling control in the case of traveling with the battery disconnected from the electric system (hereinafter, also referred to as batteryless traveling) is described.

  In the configurations of Patent Documents 1 and 2, the DC voltage of the DC voltage wiring is controlled so that the output voltage of the vehicle-mounted power storage device can be boosted by the voltage converter configured by the boost chopper during normal traveling. In Patent Document 1, in order to ensure the torque in consideration of the voltage fluctuation of the DC voltage caused by the collapse of the electric power balance of the first and second motor generators during the battery-less traveling, It is described that the torque upper and lower limit range of the second motor generator is set.

  In addition, Patent Document 2 discloses a voltage control for ensuring the operation of an auxiliary load that is supplied with electric power from the primary side (power storage device side) of a voltage converter in the same batteryless traveling as in Patent Document 1. Have been described.

JP 2012-153220 A JP, 2013-60042, A

  However, in Patent Document 2, before starting batteryless traveling, control is performed to preliminarily increase the DC voltage of the DC power supply wiring in preparation for a voltage drop on the primary side of the voltage converter, while batteryless traveling is performed. If the voltage on the primary side of the voltage converter rises or falls excessively, it is not possible to respond.

  The present invention has been made in order to solve such a problem, and is to prevent excessive voltage rise and voltage drop in an electric system during batteryless running of a hybrid vehicle.

  A hybrid vehicle according to the present invention includes first and second drive wheels, an internal combustion engine, a generator, first and second electric motors, a power storage device, first and second electric power converters, And a control device. The generator uses at least part of the power of the internal combustion engine to generate electricity. The first electric motor is configured to have a power transmission path between the first electric motor and the first drive wheel. The power storage device is electrically connected to the first power line via a switch. The first voltage converter is connected between the first power line and the second power line and is configured to perform a DC voltage conversion between the first and second power lines. The second power line is electrically connected to both the first electric motor and the generator. The second voltage converter steps down the DC voltage of the first power line and converts it into the operating voltage of the auxiliary device. The second electric motor is electrically connected to the first electric power line and has a power transmission path between the second electric motor and the second drive wheel. The control device controls the first voltage converter, the generator, and the first and second electric motors in the traveling state in which the switch is opened. The control device controls the operation of the first voltage converter so as to control the voltage of the first power line, and a generator for obtaining a vehicle driving torque according to the vehicle state, and the first and second generators. Control the power distribution among the electric motors. Furthermore, when the voltage of the first power line is lower than a predetermined control lower limit voltage, the control device causes the second electric motor to output the regenerative torque, and the first voltage converter, the generator, and While the output distribution is controlled so that the vehicle drive torque is ensured by the overall output of the first and second electric motors, the second output is controlled when the voltage of the first power line drops below a predetermined control upper limit voltage. The electric motor outputs the power running torque, and controls the output distribution so that the vehicle drive torque is secured for the entire output.

  According to the above hybrid vehicle, in traveling with the switch open (battery-less traveling), when the voltage (VL) of the first power line is out of a certain range from the control lower limit voltage to the control upper limit voltage, the second The voltage can be quickly returned to the normal range by forcibly executing the regenerative power generation or the power consumption by the electric motor. At that time, by correcting the output distribution so as to compensate the increase/decrease in the torque of the second drive wheel due to the regenerative power generation or the power consumption by the second electric motor, the vehicle drive torque according to the traveling state is also secured. be able to. Accordingly, it is possible to prevent the continuation of traveling from being disabled due to an excessive increase or decrease in the voltage (VL) of the first power line during traveling (batteryless traveling) with the switch opened.

  According to the present invention, it is possible to prevent excessive voltage rise and voltage drop in the electric system during batteryless traveling of the hybrid vehicle.

FIG. 1 is a block diagram showing a configuration of a hybrid vehicle according to an embodiment of the present invention. It is a collinear diagram regarding the drive of a front wheel. 7 is a flowchart illustrating a voltage abnormality detection process during batteryless traveling of the hybrid vehicle according to the embodiment of the present invention. 3 is a flowchart illustrating a process of traveling control during batteryless traveling of the hybrid vehicle according to the embodiment of the present invention. It is a conceptual diagram explaining an example of output distribution correction at the time of battery-less running.

  Embodiments of the present invention will be described below in detail with reference to the drawings. The same or corresponding parts in the drawings will be designated by the same reference numerals, and the description thereof will not be repeated in principle.

(Vehicle configuration and basic control)
FIG. 1 is a block diagram showing a configuration of a hybrid vehicle according to an embodiment of the present invention.

  Referring to FIG. 1, a hybrid vehicle 100 includes a power storage device 5, system main relays SMR1 and SMR2, a front power control unit (Fr-PCU: hereinafter referred to as a front wheel control unit) 11, a rear power control unit ( Re-PCU: hereinafter referred to as a rear wheel control unit) 14, an HV-ECU 8, a transaxle TA, a motor generator MGR, an engine ENG, a front wheel WF, and a rear wheel WR.

  Transaxle TA includes motor generators MG1 and MG2, and power split device PG.

  Fr-PCU 11 includes a converter 12, inverters 20 and 22, capacitors C1 and C2, and MG-ECU 9. Re-PCU 14 includes an inverter 24, a capacitor C3, and MG-ECU 10. The HV-ECU 8, the MG-ECU 9, and the MG-ECU 10 configure a control device 120.

  Power split mechanism PG is a mechanism that is coupled to engine ENG and motor generators MG1 and MG2 and splits power between them. For example, as the power split mechanism, a planetary gear mechanism having three rotation shafts (not shown) having a sun gear (S), a planetary carrier (P), and a ring gear (R) can be used. In the power split device PG, the planetary carrier (P) is mechanically connected to the crankshaft (not shown) of the engine ENG, and the sun gear (S) is mechanically connected to the rotor (not shown) of the motor generator MG1. The ring gear (R) is mechanically connected to the rotor (not shown) of the motor generator MG2. The ring gear (R) is also connected to the output shaft DS.

  By such coupling via the power split mechanism PG, it is possible to control so that the output of the engine ENG and the outputs of the motor generators MG1 and MG2 have an optimum ratio. One of motor generators MG1 and MG2 may function exclusively as an electric motor, and the other motor generator may function exclusively as a generator.

  The output shaft DS of the power split device PG, which is connected to the rotation shaft of the motor generator MG2, is mechanically connected to the front wheels WF via a reduction gear and a differential gear. That is, motor generators MG1, MG2 can receive the AC power supplied from Fr-PCU 11 and generate the torque of the front wheels WF. Further, motor generator MG1 can also generate electric power by the output of engine ENG, and motor generator MG2 can also generate electric power by regenerative braking of front wheels WF.

  The rotating shaft of the motor generator MGR drives the rear wheel WR via a reduction gear and a differential gear (not shown). That is, the motor generator MGR can receive the AC power supplied from the Re-PCU 14 and generate the torque of the rear wheels WR. The motor generator MGR can also generate electric power by regenerative braking of the rear wheels WR.

  Power storage device 5 is a power storage element that is configured to be chargeable and dischargeable, and is typically configured by a secondary battery such as a lithium ion battery, a nickel hydride battery, or a lead storage battery. Alternatively, power storage device 5 may be configured to include a power storage element other than a secondary battery such as an electric double layer capacitor.

  Power storage device 5 supplies DC power for driving motor generators MG1 and MG2 to Fr-PCU 11, and supplies DC power for driving motor generator MGR to Re-PCU 14. Power storage device 5 stores electric power generated by motor generators MG1 and MG2 and supplied via Fr-PCU 11. Power storage device 5 stores the electric power generated by motor generator MGR and supplied via Re-PCU 14.

  System main relays SMR1 and SMR2 are inserted in the middle of power line PL1 and ground line SL1 that connect power storage device 5 to Fr-PCU11 and Re-PCU14. System main relays SMR1 and SMR2 are controlled by HV-ECU 8. Power line PL1 and ground line SL1 are connected to Fr-PCU11.

  Fr-PCU 11 converts DC power from power storage device 5 into AC power and supplies the AC power to motor generators MG1 and MG2. Further, Fr-PCU 11 converts the AC power generated by motor generators MG1 and MG2 into DC power to charge power storage device 5.

  The converter 12 includes a so-called step-up chopper circuit, and is connected in antiparallel to the reactor L1, the switching elements Q1 and Q2 connected in series between the power line HPL and the ground line SL1, and the switching elements Q1 and Q2, respectively. And the diodes D1 and D2. As the switching element, typically, an IGBT (Insulated Gate Bipolar Transistor), a bipolar transistor, a MOSFET (Metal Oxide Semiconductor), or the like can be applied. In the present embodiment, the IGBT is exemplified as the switching element.

  Converter 12 controls DC voltage VH between power line HPL and ground line SL1 in accordance with the voltage command value by alternately turning on and off switching elements Q1 and Q2 based on signal PWC from MG-ECU 9. Specifically, the voltage conversion ratio between the DC voltage VL between the power line PL1 and the ground line SL1 and the DC voltage VH is determined by the ON period ratio (duty ratio) of the switching elements Q1 and Q2 in each predetermined switching cycle. Controlled.

  The capacitor C2 is connected between the power line HPL on the high voltage side of the converter 12 (that is, between the converter 12 and the inverters 20 and 22) and the ground line SL1. As a result, converter 12 and inverters 20 and 22 absorb the ripple voltage generated during switching, so that DC voltage VH is smoothed.

  Similarly, the capacitor C1 is connected between the power line PL1 on the low voltage side of the converter 12 (that is, between the converter 12 and the power storage device 5) and the ground line SL1, and absorbs the ripple voltage at the time of switching the switching elements Q1 and Q2. By doing so, the DC voltage VL is smoothed.

  Inverter 20 is connected between power line HPL, ground line SL1 and motor generator MG1. Inverter 20 has a general three-phase converter configuration including U-phase arm 123, V-phase arm 124, and W-phase arm 125. U-phase arm 123, V-phase arm 124 and W-phase arm 125 are connected in parallel between power line HPL and ground line SL1.

  U-phase arm 123 has switching elements Q3 and Q4 connected in series between power line HPL and ground line SL1, and diodes D3 and D4 connected in antiparallel with switching elements Q3 and Q4. V-phase arm 124 has switching elements Q5 and Q6 and diodes D5 and D6 which are similarly connected. Similarly, V-phase arm 124 has switching elements Q7 and Q8 and diodes D7 and D8.

  Motor generator MG1 is formed of, for example, a permanent magnet type three-phase synchronous motor. A three-phase coil (not shown) Y-connected at a neutral point is wound around a stator (not shown) of motor generator MG1, and each one end of the three-phase coil is connected to the neutral point together. At the same time, the other end of each phase is electrically connected to U-phase arm 123, V-phase arm 124, and W-phase arm 125, as shown in FIG.

  Inverter 20 turns on or off the gate signals of switching elements Q3 to Q8 according to drive command PWI1 output from MG-ECU 9. Thereby, inverter 20 performs motor/generator MG1 according to an output command (for example, torque command value Tmg1*) by AC/DC power conversion between DC voltage VH and AC voltage applied to the three-phase coil of motor generator MG1. To drive. For example, motor generator MG1 is driven to start engine ENG. Alternatively, motor generator MG1 may be driven to generate electric power by mechanical power transmitted from engine ENG. At this time, inverter 20 converts the generated power (AC) of motor generator MG1 into DC voltage VH. Further, by the voltage conversion in converter 12, power storage device 5 can be charged with the electric power generated by the engine power.

  Similarly to inverter 20, inverter 22 is formed of a three-phase inverter and is connected between power line HPL and ground line SL1 and motor generator MG2 driving front wheel WF. The motor generator MG2 is composed of a permanent magnet type three-phase synchronous motor, like the motor generator MG1.

  Inverter 22 is connected in parallel to inverter 20 with respect to converter 12, and turns on or off the gate signal of the switching element (not shown) according to drive command PWI2 output from MG-ECU 9. Thus, the AC/DC power conversion between the DC voltage VH and the AC voltage applied to the three-phase coil (not shown) of motor generator MG2 allows the motor generator to follow the output command (for example, torque command value Tmg2*). MG2 is driven.

  Motor generator MG2 is driven to output the torque of front wheels WF. Alternatively, motor generator MG2 can perform regenerative braking by the rotational force of front wheels WF during vehicle deceleration. At the time of regenerative braking, inverter 22 converts the electric power generated by motor generator MG2 into DC voltage VH. Furthermore, by the voltage conversion in converter 12, power storage device 5 can be charged using the electric power regenerated.

Next, the configuration for driving the rear wheels will be described.
Power line PL2 and ground line SL2 are connected to power line PL1 and ground line SL1, respectively. Therefore, when system main relays SMR1 and SMR2 are turned on, power line PL2 and ground line SL2 are connected to power storage device 5 in parallel with power line PL1 and ground line SL1. Even when system main relays SMR1 and SMR2 are turned off, electrical connection between power line PL2 and ground line SL2 and power line PL1 and ground line SL1 is maintained.

  Similarly to inverters 20 and 22, inverter 24 is formed of a three-phase inverter and is connected between power line PL2 and ground line SL2 and motor generator MGR that drives rear wheel WR. The motor generator MGR is composed of a permanent magnet type three-phase synchronous motor, like the motor generators MG1 and MG2.

  Inverter 22 turns on or off the gate signal of the switching element (not shown) according to drive command PWI3 output from MG-ECU 10. Accordingly, an output command (for example, a torque command) is generated by AC/DC power conversion between the DC voltage VL before boosting by converter 12 and the AC voltage applied to the three-phase coil (not shown) of motor generator MGR. The motor generator MGR is driven according to the value Tmgr*).

  Motor generator MGR is driven to output the torque of rear wheel WR. Alternatively, motor generator MGR can perform regenerative braking by the rotational force of rear wheels WR during vehicle deceleration. At the time of regenerative braking, the inverter 24 converts the electric power generated by the motor generator MGR into the DC voltage VL. Thereby, power storage device 5 can be charged with the regenerated electric power.

  Capacitor C3 is connected between power line PL2 between inverter 24 and power storage device 5 and ground line SL2, and absorbs the ripple voltage generated in inverter 24 during switching, thereby generating a DC voltage between power line PL2 and ground line SL2. Smooth VL fluctuations.

  The operating voltage of the auxiliary load 130 is generated from the DC voltage VH. DC/DC converter 132 is connected to power line PL2 and ground line GL2 to reduce DC voltage VL to the operating voltage of auxiliary load 130. Auxiliary equipment load 130 includes, for example, electric devices in the vehicle interior such as audio, headlights, various electric motors other than motor generators MG1, MG2, MGR, and the like.

  The auxiliary battery 135 is connected to the auxiliary load 130, and when the power supplied by the DC/DC converter 132 is larger than the power consumption of the auxiliary load 130, the auxiliary battery 135 is charged by the surplus power. To be done. On the contrary, when the power consumption of the auxiliary load 130 is larger than the power supplied by the DC/DC converter 132, the operation of the auxiliary load 130 is ensured by discharging the auxiliary battery 135.

  Each of HV-ECU 8, MG-ECU 9, and MG-ECU 10 is configured as an electronic control unit having a CPU (Central Processing Unit), a memory, an input/output port, a communication port, and the like, which are not shown. Each ECU is configured to be able to send and receive data and information to and from each other.

  The HVECU 8 includes an ignition signal from an ignition switch (not shown), a signal for detecting an operation position of a shift lever (not shown), an accelerator opening degree which is a depression amount of an accelerator pedal (not shown), and a brake pedal (not shown). The brake pedal position indicating the amount of depression of the vehicle (not shown), the vehicle speed detected by a vehicle speed sensor (not shown), and the like are input. The HV-ECU 8 can also acquire the detected values of the DC voltages VL and VH by input from a voltage sensor (not shown) or by transmission from another ECU.

  The HV-ECU 8 generates a relay control signal SE according to the vehicle state and controls on/off of the system main relays SMR1 and SMR2. Specifically, while the vehicle is in operation with the ignition switch turned on, the relay control signal SE is set to on so that the contacts of the system main relays SMR1 and SMR2 are closed (on state), and the power storage device 5 And Fr-PCU 11 and Re-PCU 14 are connected.

  On the other hand, when the relay control signal SE is set to OFF, the contacts of the system main relays SMR1 and SMR2 are opened (OFF state), so that the power path between the power storage device 5 and the Fr-PCU11 and Re-PCU14. Is cut off. For example, HV-ECU 8 outputs a relay control signal SE to turn off system main relays SMR1 and SMR2 at the end of the operation when the ignition switch is turned off.

  The HV-ECU 8 executes traveling control for traveling suitable for the vehicle state. For example, when the vehicle starts and runs at low speed, hybrid vehicle 100 runs with the output of motor generator MG2 with engine ENG stopped. During steady running, engine ENG is started, and hybrid vehicle 100 runs with the outputs of engine ENG and motor generator MG2. In particular, operating the engine ENG at a highly efficient operating point improves the fuel efficiency of the hybrid vehicle 100.

  Specifically, in traveling control, HV-ECU 8 calculates total torque Ttl of hybrid vehicle 100 in accordance with the traveling state (for example, vehicle speed and accelerator opening). The total torque Ttl of the hybrid vehicle 100 is the sum of the front wheel torque Twf and the rear wheel torque Twb (Ttl=Twf+Twb). Therefore, the HV-ECU 8 distributes the total torque Ttl to the front wheel torque Twf and the rear wheel torque Twb. At this time, it is possible to set one of the front wheel torque Twf and the rear wheel torque Twb to a negative value with respect to the positive total torque Ttl (Ttl>0). In this case, the other of the front wheel torque Twf and the rear wheel torque Twb is set to a positive torque larger than the total torque Ttl.

  Further, HV-ECU 8 sets output commands (for example, torque command values Tmg1*, Tmg2*) of engine ENG, motor generator MG1 and motor generator MG2 to secure front wheel torque Twf, and rear wheel torque Twb. The output command (for example, torque command value Tmgr*) of the motor generator MGR is set to ensure that. In this way, the output distribution of engine ENG, motor generator MG1 and motor generator MG2, and motor generator MGR for ensuring total torque Ttl is controlled.

  With respect to the drive of the front wheels WF, the engine ENG, the motor generator MG1 and the motor generator MG2 are coupled via the power split mechanism PG, so that the engine ENG, the motor generator MG1 and the motor generator MG2 have the rotational speeds as shown in FIG. It becomes a relationship that is connected by a nomographic chart. In the following, it is assumed that the gear ratio between the rotation speed Nmg2 of motor generator MG2 and the rotation speed of output shaft DS of power split device PG is fixed at 1.

  Referring to FIG. 2, engine ENG is controlled to operate at an operating point (engine speed Ne and engine torque Te) determined based on the required engine power set along the output distribution.

  The torque Tmg1 and the rotation speed Nmg1 of the motor generator MG1 are controlled so that the engine rotation speed Ne becomes the target rotation speed according to the operating point. During normal traveling, MG1 outputs a negative torque (Tmg1<0) and is in a state of generating power.

  At this time, the direct torque Tep transmitted to the output shaft DS by the torque Tmg1 output so as to bear the reaction force of the engine torque Te is represented by Tep=−Tmg1×(1/ρ). Note that ρ is a gear ratio in the power split mechanism PG.

  On the other hand, when the gear ratio=1 as described above, the torque Tmg2 of the motor generator MG2 acts on the output shaft DS as it is. Therefore, the following equation (1) is established for the front wheel torque Twf.

Twf=Tmg2-Tmg1×(1/ρ) (1)
When the vehicle is running, the motor generator MG2 mainly operates as an “electric motor” and the motor generator mainly operates as a “generator” (Tmg2>0, Tmg1<0). It

  Then, the total torque Ttl corresponding to the accelerator operation is secured by the sum of the front wheel torque Twf and the rear wheel torque Twb.

(Batteryless driving)
Next, batteryless traveling of the hybrid vehicle 100 will be described.

  In hybrid vehicle 100, when abnormality occurs in power storage device 5 and charging/discharging is prohibited, relay control signal SE is generated to turn off system main relays SMR1 and SMR2. Accordingly, battery-less traveling, which is traveling in which power storage device 5 is not used, can be executed with power storage device 5 disconnected from the electrical system.

  Even in battery-less traveling, the front wheel torque Twf is output according to the collinear chart shown in FIG. 2, and the rear wheel torque Twb corresponds to the output torque of the motor generator MGR. That is, even in battery-less traveling, the total torque Ttl is secured by the sum of the front wheel torque Twf and the rear wheel torque Twb.

  As described in Patent Documents 1 and 2, during batteryless traveling, power storage device 5 cannot be used as a power buffer. Therefore, input/output power ΔP (ΔP=Tmg1×Nmg1+Tmg2) in motor generators MG1 and MG2 as a whole. ×Nmg2) directly changes the DC voltage VH. On the other hand, if the DC voltage VH is excessively decreased or increased, battery-less traveling may be impossible to continue.

  For this reason, in batteryless traveling, as described in Patent Documents 1 and 2, the motor is adjusted so that the adjustment of the DC voltage VH by adjusting the input/output power ΔP (power control) and the securing of the front wheel torque Twf are both achieved. It is necessary to set the outputs of generators MG1, MG2 and engine ENG.

  Further, during batteryless traveling, as described in Patent Document 2, converter 12 can operate to control DC voltage VL in accordance with voltage command value VLr. That is, the duty ratios of the switching elements Q1 and Q2 are controlled according to the detected values of the DC voltages VL and VH and the voltage command value VLr. Hereinafter, such control is also simply referred to as “VL control”.

  Even during battery-less traveling, if the DC voltage VL rises excessively, the breakdown voltage of the device may be destroyed. On the other hand, if the DC voltage VL falls excessively, it may be difficult to operate the auxiliary load 130. Therefore, in order to continue the batteryless traveling, it is necessary to control the DC voltage VL within a certain range.

  Therefore, in the present embodiment, during battery-less traveling, traveling control is executed so as to maintain DC voltage VL within the range of control lower limit voltage VLmin to control upper limit voltage VLmax.

  3 and 4 show the processing in the traveling control when the hybrid vehicle 100 is traveling without the battery. FIG. 3 shows the VL voltage abnormality detection processing, and FIG. 4 shows the details of the traveling control. The processes of FIGS. 3 and 4 are repeatedly executed by the HV-ECU 8 in a predetermined cycle.

  Referring to FIG. 3, HV-ECU 8 determines in step S100 whether or not the vehicle is running without a battery. If the vehicle is running without batteries (NO in step S100), the processes in step S110 and thereafter are not executed.

  During batteryless traveling (when YES is determined in S100), HV-ECU 8 instructs converter 12 to execute VL control in step S110. In response to this, MG-ECU 9 generates signal PWC of converter 12 so as to control DC voltage VL at voltage command value VLr.

  Further, in steps S120 and S130, HV-ECU 8 samples DC voltage VL and determines whether DC voltage VL is within the normal range. Specifically, in step S120, it is determined whether VL>VLmax, and in step S130, it is determined whether VL<VLmin.

  The HV-ECU 8 sets VL abnormality flag Fvl=0 in step S140 when VLmin≦VL≦VLmax (when determining NO in S120 and S130), that is, when the DC voltage VL is within the normal range. .

  On the other hand, the HV-ECU 8 sets VL abnormality flag Fvl=1 in step S150 when VL>VLmax (when YES is determined in S120), that is, when the DC voltage VL is higher than the control upper limit voltage. At the same time, the increase request flag FVup=0 is set.

  Further, when VL<VLmin (when YES is determined in S130), that is, when the DC voltage VL is lower than the control lower limit voltage, the HV-ECU 8 sets the VL abnormality flag Fvl=1 in step S160. , Rise request flag FVup=1 is set.

  As described above, the VL abnormality flag Fvl and the increase request flag FVup provide information that identifies whether the DC voltage VL is abnormal and whether the abnormality is on the rising side or the falling side. The information is reflected in the output distribution in the traveling control shown in FIG.

  Referring to FIG. 4, HV-ECU 8 determines in step S200 whether or not the vehicle is running without a battery. When the vehicle is not traveling without a battery (when NO is determined in step S200), the processes of step S210 and thereafter are not executed. In this case, traveling control during normal traveling is separately executed.

  During batteryless traveling (when YES is determined in S200), HV-ECU 8 calculates total torque Ttl of hybrid vehicle 100 from the traveling state in step S210. For example, the process of step S210 can be realized by previously creating a map that sets the total torque Ttl during batteryless traveling from the two variables using the accelerator opening Acc and the vehicle speed of the hybrid vehicle 100 as parameters.

  The HV-ECU 8 tentatively determines the basic output distribution for securing the total torque Ttl in step S220. In step S220, the outputs of engine ENG and motor generators MG1, MG2, MGR are set so that rear wheel torque Twb=0 and total torque Ttl is generated only by front wheel torque Twf (Ttl=Twf).

  Specifically, after setting Twr=0, that is, Tmgr=0, Tfr=Ttl is output according to the alignment chart shown in FIG. 2, and power control of the DC voltage VH is realized. At, the operating point of engine ENG and torques Tmg1r and Tmg2r of motor generators MG1 and MG2 are set. For example, Tmg1r and Tmg2r can be set by a method similar to that of Patent Document 1 or 2. At this time, in addition to Tmg1r and Tmg2r, the upper and lower limit values of Tmg1 and Tmg2 are further set. The upper and lower limit values are set, for example, in correspondence with the torque range for preventing the power control from failing.

  The HV-ECU 8 checks the VL abnormality flag Fvl in step S230. Then, when Fvl=0 (when NO is determined in S230), that is, when the DC voltage VL is within the normal range, the process proceeds to step S250.

  In step S250, HV-ECU 8 maintains the output distribution in step S220 and sets torque command values Tmg1*, Tmg2*, Tmgr*. As a result, Tmgr*=0 and Tmg1*=Tmgr1 (S220) and Tmg2*=Tmg2r (S220) are set.

  When the VL abnormality flag Fvl=1 (when YES is determined in S230), the HV-ECU 8 sets the upper and lower limit values (S220) of the torques Tmg1r and Tmg2r set in step S220 in step S240. Is determined to be equal to. When either of Tmg1r and Tmg2r is equal to the upper and lower limit values (when YES is determined in S240), HV-ECU 8 determines that there is no room to correct the output distribution and advances the process to step S250. As a result, the torque command values Tmg1*, Tmg2*, Tmgr* of motor generators MG1, MG2, MGR are set while maintaining the distribution at step S220.

  On the other hand, when there is a margin to change the output distribution (when the NO determination is made in S240), the HV-ECU 8 advances the processing to step S260 and confirms the increase request flag FVup. Then, when FVup=1 (when YES is determined in S260), that is, when DC voltage VL is lower than control lower limit voltage VLmin and voltage increase is required, HV-ECU 8 advances the process to step S270. , Modify output allocation.

  In step S270, torque command value Tmgr*<0 (negative value) is set so that motor generator MGR generates power by the output of the regenerative torque. At this time, Tmgr may be a predetermined value, or may be variably set according to the amount of increase (VL-VLmax) with respect to the control upper limit voltage VLmax. Tmgr<0, that is, when the motor generator MGR generates power by the output of the regenerative torque, the DC voltage VL can be increased.

  Further, by setting Tmgr<0, the front wheel torque Twf is increased by the negative torque, and the output distribution is corrected so that the total torque Ttl (S210) is secured. Specifically, the operation point of the engine ENG and the motor generator are corrected by the process similar to step S220 so as to correct Twf=Ttl-Tmgr=Ttl+|Tmgr| and to secure the corrected front wheel torque Twf. The Tmg1* and Tmg2* of MG1 and MG2 are set. At this time, if the torque command values Tmg1* and Tmg2* cannot be set within the upper and lower limit values, it is necessary to reduce the absolute value of the torque command value Tmgr* and recalculate. ..

  On the other hand, when FVup=0 (when NO is determined in S260), that is, when the DC voltage VL also increases the control upper limit voltage VLmax and the voltage needs to be decreased, the HV-ECU 8 advances the process to step S280. , Modify output allocation.

  In step S280, torque command value Tmgr*>0 (positive value) is set such that motor generator MGR consumes electric power due to the output of power running torque. At this time, Tmgr may be a predetermined value or may be variably set according to the amount of decrease (VLmin-VL) with respect to the control upper limit voltage VLmax. Tmgr>0, that is, the motor generator MGR consumes electric power due to the output of the power running torque, so that the DC voltage VL can be reduced.

  Further, by setting Tmgr>0, the front wheel torque Twf is reduced by the positive torque, and the output distribution is corrected so that the total torque Ttl (S210) is secured. Specifically, Twf=Ttl-Tmgr (Tmgr>0) is corrected, and the same operation as in step S220 is performed so as to ensure the corrected front wheel torque Twf. Torque command values Tmg1* and Tmg2* for MG1 and MG2 are set. Also at this time, if the torque command values Tmg1* and Tmg2* cannot be set within the upper and lower limit values, the recalculation similar to step S270 is executed.

FIG. 5 is a conceptual diagram illustrating an example of output distribution correction during battery-less traveling.
Referring to FIG. 5, in the output distribution when the DC voltage VL is within the normal range (Fvl=0), Tmgr=0 is set in the motor generator MGR, and Tmg2>0 in the motor generators MG1 and MG2. , Tmg1<0, the total torque Ttl is secured.

  On the other hand, at the time of boosting VL where VL<VLmin (VLup=1), Tmgr=0 is corrected to Tmgr<0. Further, in order to compensate for the decrease in the driving force due to Tmgr<0, the torque command values Tmg1*, Tmg1*, of the motor generators MG1, MG2 are set so as to secure Twf (Twf=Ttl−Tmgr) which is larger than Ttl by |Tmgr|. Tmg2* is modified. As a result, the DC voltage VL is increased by the regenerative power generation of the motor generator MGR, and the output distribution of the engine ENG and the motor generators MG1, MG2, MGR is corrected so as to secure the total driving force (S210) according to the running state. To be done.

  On the other hand, when VL is lowered (VLup=0) such that VL>VLmin, Tmgr=0 is corrected to Tmgr>0. Further, in order to compensate for the increase in driving force due to Tmgr>0, torque command values Tmg1*, Tmg2* of the motor generators MG1, MG2 are output so as to output Twf (Twf=Ttl−Tmgr) that is smaller than Ttl by Tmgr. Is fixed. As a result, the DC voltage VL is reduced by the power consumption of the motor generator MGR, and the output distribution of the engine ENG and the motor generators MG1, MG2, MGR is corrected so as to secure the total driving force (S210) according to the running state. To be done.

  As described above, according to the vehicle according to the present embodiment, when the DC voltage VL is out of the fixed range (VLmin≦VL≦VLmax) during battery-less traveling, the regenerative power generation or the power consumption of motor generator MGR is forced. By executing the above-mentioned method, it is possible to quickly eliminate the excessive rise or the excessive fall of the DC voltage VL. At this time, by performing the output distribution correction as shown in FIG. 5, it is possible to secure the total torque Ttl of the vehicle according to the traveling state. As a result, it is possible to prevent the continuation of traveling from being impossible due to excessive rise or fall of the DC voltage VL during batteryless traveling, so that it is possible to secure a traveling distance for batteryless traveling.

  In the present embodiment, in batteryless traveling, motor generator MG1 corresponds to an example of “generator”, motor generator MG2 corresponds to an example of “first electric motor”, and motor generator MGR is “ It corresponds to an example of the "second electric motor". Similarly, the front wheels WF correspond to the “first drive wheels” and the rear wheels WR correspond to the “second drive wheels”. Furthermore, since the converter 12 corresponds to the “first voltage converter” and the DC/DC converter 132 corresponds to the “second voltage converter”, the power line PL1 corresponds to the “first power line” and the power line PL1 corresponds to the “first power line”. HPL corresponds to the "second power line".

  It should be noted that the configuration of the hybrid vehicle to which the present invention is applied is not limited to the example shown in FIG. For example, even when motor generator MG1 is formed of a dedicated generator for engine output, the output torque of motor generator MGR is similarly controlled to prevent the DC voltage VL from excessively increasing and decreasing. it can.

  The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

  5 power storage device, 11 Fr-PCU, 12 converter, 14 Re-PCU, 20, 22, 24 inverter, 100 hybrid vehicle, 120 control device, 123, 124, 125 arm, 130 auxiliary load, 132 DC/DC converter, 135 Auxiliary battery, C1 to C3 capacitor, D1 to D8 diode, DS output shaft, ENG engine, FVup rising request flag, Fvl VL abnormality flag, GL2, SL1, SL2 ground line, HPL, PL1, PL2 power line, L1 reactor, MG1, MG2, MGR Motor generator, PG Power split mechanism, PWC signal (converter), PWI1 to PWI3 drive command (inverter), Q1 to Q8 switching element, SE relay control signal, SMR1, SMR2 system main relay, TA transaxle, Tep Direct torque, Tmg1*, Tmg2*, Tmgr* Torque command value, Ttl total torque, Twb rear wheel torque, Twf front wheel torque, VH, VL DC voltage, VLmax control upper limit voltage, VLmin control lower limit voltage, WF front wheel, WR rear ring.

Claims (1)

First and second drive wheels,
An internal combustion engine,
A generator for generating power using at least a part of the power of the internal combustion engine,
A first electric motor configured to have a power transmission path with the first drive wheel;
A power storage device electrically connected to the first power line via a switch;
A DC voltage is connected between the first power line and a second power line electrically connected to both the first electric motor and the generator, and a DC voltage is applied between the first and second power lines. A first voltage converter configured to perform the conversion;
A second voltage converter for stepping down the DC voltage of the first power line and converting it into an operating voltage of an auxiliary machine;
A second electric motor electrically connected to the first electric power line and configured to have a power transmission path between the first electric power line and the second drive wheel;
A control device for controlling the internal combustion engine, the first voltage converter, the generator, and the first and second electric motors in a traveling state in which the switch is opened,
The control device is
An operating point of the internal combustion engine for controlling the operation of the first voltage converter so as to control the voltage of the first power line and obtaining a vehicle driving torque according to a vehicle state; , the generator, and, by controlling the output distribution between the first and second electric motors,
The control device further includes
When the voltage of the first power line drops below a predetermined control lower limit voltage, the second electric motor outputs regenerative torque, and the first voltage converter, the generator, the internal combustion engine, In addition, while controlling the output distribution so that the vehicle drive torque is secured by the entire output of the first and second electric motors, the voltage of the first power line has risen above a predetermined control upper limit voltage. In this case, the second electric motor outputs a power running torque, and controls the output distribution so that the vehicle driving torque is secured by the entire output.

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