JP2017114209A - Hybrid vehicle - Google Patents

Abstract

An object of the present invention is to suppress an excessive increase in rotation of a motor generator (MG1) when switching from a forward range to a non-forward range during inverterless travel. In a hybrid vehicle including an engine, MG1, MG2, a planetary gear mechanism that couples them, a battery, a converter, and an inverter, an ECU performs inverterless traveling that places the inverter in a gate-cut off state and drives the engine in a driving state. Execute control. During the inverterless running, the ECU operates the converter during the forward range to generate counter electromotive torque from the MG1, and cuts the counter electromotive torque by setting the converter to the gate cutoff state during the non-forward range. The ECU calculates a predicted value of the MG1 rotational speed when switching to the non-forward range during inverterless traveling and during the forward range, and the engine rotational speed so that the calculated predicted value does not exceed the threshold value. To control. [Selection] Figure 8

Description

  The present invention relates to a hybrid vehicle capable of traveling using at least one power of an engine and a rotating electrical machine.

  Japanese Patent Laid-Open No. 2013-203116 (Patent Document 1) discloses an engine, a first rotating electrical machine having a permanent magnet in a rotor, a second rotating electrical machine, a planetary gear mechanism, a battery, and a voltage input from the battery. A hybrid vehicle is disclosed that includes a converter that boosts and outputs a voltage, and an inverter that performs power conversion between the converter and the first rotating electric machine and the second rotating electric machine. The planetary gear mechanism includes a sun gear coupled to the first rotating electrical machine, a ring gear coupled to the second rotating electrical machine, and a carrier coupled to the engine.

  In this hybrid vehicle, when there is an abnormality in which the electric drive of the first rotating electric machine and the second rotating electric machine by the inverter cannot be normally performed, the engine is driven while the inverter is in a gate cutoff state, and the vehicle is “Inverter-less travel control” for retreat travel is executed. During inverterless travel control, the first rotating electrical machine is caused to generate a counter electromotive voltage by mechanically rotating the first rotating electrical machine by the rotational force of the engine. When the counter electromotive voltage of the first rotating electric machine exceeds the output side voltage of the converter, a current flows from the first rotating electric machine toward the battery, and torque caused by the counter electromotive voltage (hereinafter referred to as “counter electromotive torque”) flows to the first rotating electric machine. "). When this counter electromotive torque acts on the sun gear from the first rotating electrical machine, a driving torque acting in the forward direction (forward direction) is generated in the ring gear as a reaction force of the counter electromotive torque of the first rotating electrical machine. Retreat travel is realized by this drive torque.

JP 2013-203116 A

  In general, vehicle shift ranges (travel ranges) include forward ranges such as D (drive) range and B (brake) range, P (parking) range, R (reverse) range, and N (neutral) range. And non-advanced ranges such as

  For example, when the hybrid vehicle temporarily stops during the above inverterless travel control, the shift range may be switched from the forward range to the non-forward range. Even if the shift range is a non-forward range, if the first rotating electrical machine is mechanically rotated by the engine, the reaction force of the counter electromotive torque of the first rotating electrical machine acts on the drive wheels. The driving torque does not become zero. That is, there is a concern that torque (hereinafter also referred to as “forward torque”) that acts in the direction in which the vehicle moves forward is generated in the drive wheels even though the shift range is the non-forward range.

  As a measure for suppressing the generation of forward torque when in the non-forward range, for example, it is conceivable to place the converter in the gate cutoff state while maintaining the engine in the driving state. When the converter is in the gate cutoff state, the current flowing from the first rotating electric machine toward the battery is cut off, so that the counter electromotive torque of the first rotating electric machine can be cut while maintaining the engine in the driving state. However, since the counter electromotive torque of the first rotating electrical machine (braking torque that hinders the rotation of the first rotating electrical machine) that is balanced with the engine torque is eliminated, the rotational speed of the first rotating electrical machine is transiently excessive due to the engine torque. There is concern that it will rise. If the rotational speed of the first rotating electrical machine increases excessively, for example, the back electromotive voltage of the first rotating electrical machine becomes excessively large, and there is a concern that an overvoltage state may occur in which the output voltage of the converter becomes excessively high. .

  The present invention has been made to solve the above-described problem, and its purpose is to maintain the engine in a driving state when the shift range is switched from the forward range to the non-forward range during inverterless travel control, And it is suppressing generation | occurrence | production of a forward torque, suppressing that the rotational speed of a 1st rotary electric machine rises excessively.

  The hybrid vehicle according to the present invention includes any one of an engine, a first rotating electrical machine having a permanent magnet in a rotor, an output shaft connected to a drive wheel, a carrier connected to the engine, a first rotating electrical machine, and an output shaft. A planetary gear mechanism having a sun gear connected to one of them and a ring gear connected to the other of the first rotating electrical machine and the output shaft and mechanically connecting the engine, the first rotating electrical machine and the output shaft; The second rotating electrical machine connected to the battery, the battery, the converter configured to be able to perform voltage conversion between the battery and the power line, and the power conversion between the power line, the first rotating electrical machine and the second rotating electrical machine. An inverter configured to be executable, and a control device capable of executing inverterless travel control that places the inverter in a gate cutoff state and drives the engine. When the shift range of the hybrid vehicle is the forward range during the execution of the inverterless travel control, the control device generates torque caused by the counter electromotive voltage from the first rotating electrical machine by bringing the converter into an operating state, and shifts the shift range. When the range is a non-advanced range, the torque caused by the counter electromotive voltage is cut by putting the converter in a gate cutoff state. When the shift range is the forward range during the execution of the inverterless travel control, the control device rotates the output torque of the engine and the rotational speed of the first rotating electrical machine when the rotational speed of the first rotating electrical machine is switched from the rotational speed of the first rotating electrical machine. Is calculated, and the engine speed is controlled so that the predicted value of the rotation speed of the first rotating electrical machine does not exceed the threshold value.

  According to the above configuration, when the shift range is the non-advanced range during the inverterless travel control, the converter is put into the gate cutoff state, and thus the counter electromotive torque of the first rotating electrical machine is cut. Thereby, generation | occurrence | production of a forward torque can be suppressed, maintaining an engine in a drive state. Further, when the shift range is the forward range, a predicted value of the rotational speed of the first rotating electrical machine when the shift range is switched to the non-forward range is calculated, and the engine rotational speed is set so that the predicted value does not exceed the threshold value. Be controlled. Therefore, even when the shift range is switched to the non-advanced range, the rotation speed of the first rotating electrical machine can be prevented from excessively exceeding the threshold value. As a result, when the shift range is switched from the forward range to the non-forward range during inverterless travel control, the engine is maintained in the driving state and the rotational speed of the first rotating electrical machine is prevented from excessively increasing. Meanwhile, the generation of forward torque can be suppressed.

1 is a block diagram schematically showing an overall configuration of a vehicle. It is a circuit block diagram for demonstrating the structure of the electric system of a vehicle. It is a figure which shows roughly the state of an electric system in case a shift range is a forward range during inverterless driving | running | working. It is a figure which shows an example of the control state in case a shift range is a forward range during inverterless driving | running | working on a nomograph. It is a figure which shows roughly the state of an electric system in case a shift range is a non-advanced range during inverterless driving | running | working. It is a flowchart (the 1) which shows the process sequence of ECU. It is a figure which shows an example of a state change in case a shift range is switched from a forward range to a non-forward range during inverterless driving | running | working on a nomograph. It is a flowchart (the 2) which shows the process sequence of 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.

<Overall configuration of vehicle>
FIG. 1 is a block diagram schematically showing an overall configuration of a vehicle 1 according to the present embodiment. The vehicle 1 includes an engine 100, a motor generator (first rotating electrical machine) 10, a motor generator (second rotating electrical machine) 20, a planetary gear mechanism 30, driving wheels 50, and an output shaft connected to the driving wheels 50. 60, a vehicle speed sensor 71, a battery 150, a system main relay (SMR) 160, a power control unit (PCU) 200, an electronic control unit (ECU) 300, Is provided.

  The vehicle 1 is a hybrid vehicle that travels using at least one power of the engine 100 and the motor generator 20. The vehicle 1 travels using an electric vehicle (hereinafter referred to as “EV traveling”) that uses the power of the motor generator 20 without using the power of the engine 100 during normal traveling, which will be described later, and both the engine 100 and the motor generator 20. The traveling mode can be switched between hybrid vehicle traveling (hereinafter referred to as “HV traveling”) that travels using the power of the vehicle.

  The engine 100 is an internal combustion engine such as a gasoline engine or a diesel engine. Engine 100 generates motive power for vehicle 1 to travel in response to a control signal from ECU 300. The power generated by the engine 100 is output to the planetary gear mechanism 30.

  The engine 100 is provided with an engine rotation speed sensor 410. Engine rotation speed sensor 410 detects a rotation speed (engine rotation speed) Ne of engine 100 and outputs a signal indicating the detection result to ECU 300.

  Each of motor generators 10 and 20 is a three-phase AC permanent magnet type synchronous motor. When starting the engine 100, the motor generator 10 uses the electric power of the battery 150 to rotate the crankshaft 110 of the engine 100. The vehicle 1 does not include a starter that generates torque for cranking the engine using the power of an auxiliary battery (not shown).

  The motor generator 10 can also generate power using the power of the engine 100. The AC power generated by the motor generator 10 is converted into DC power by the PCU 200 and the battery 150 is charged. In some cases, AC power generated by the motor generator 10 is supplied to the motor generator 20 via the PCU 200.

  The rotor of motor generator 20 is connected to output shaft 60. Motor generator 20 rotates output shaft 60 using electric power supplied from at least one of battery 150 and motor generator 10. The motor generator 20 can also generate electric power by regenerative braking. The AC power generated by the motor generator 20 is converted into DC power by the PCU 200 and the battery 150 is charged.

  The planetary gear mechanism 30 is configured to mechanically connect the engine 100, the motor generator 10, and the output shaft 60, and to transmit torque between the engine 100, the motor generator 10, and the output shaft 60. Specifically, the planetary gear mechanism 30 includes, as rotating elements, a sun gear S coupled to the rotor of the motor generator 10, a ring gear R coupled to the output shaft 60, and a carrier coupled to the crankshaft 110 of the engine 100. CA and a pinion gear P meshing with the sun gear S and the ring gear R are included. The carrier CA holds the pinion gear P so that the pinion gear P can rotate and revolve.

  The battery 150 is a lithium ion secondary battery configured to be rechargeable. The battery 150 may be another secondary battery such as a nickel hydride secondary battery.

  SMR 160 is connected in series to a power line between battery 150 and PCU 200. SMR 160 switches between a conduction state and a cutoff state between battery 150 and PCU 200 in accordance with a control signal from ECU 300.

  PCU 200 boosts the DC power stored in battery 150, converts the boosted voltage to an AC voltage, and supplies it to motor generator 10 and motor generator 20. PCU 200 converts AC power generated by motor generator 10 and motor generator 20 into DC power and supplies it to battery 150. The configuration of the PCU 200 will be described in detail with reference to FIG.

  The vehicle speed sensor 71 detects the rotational speed of the drive wheel 50 as the speed (vehicle speed) VS of the vehicle 1 and outputs a signal indicating the detection result to the ECU 300.

  The vehicle 1 further includes a shift lever 500 and a position sensor 510. The shift lever 500 is a device for the user to set the shift range of the vehicle 1. When the user operates the shift lever 500, the position sensor 510 detects the position (shift position) SFT of the shift lever 500 and outputs a signal indicating the detection result to the ECU 300. ECU 300 sets a shift range corresponding to shift position SFT. The shift range includes a forward range such as a D (drive) range and a B (brake) range, and a non-forward range such as a P (parking) range, an R (reverse) range, and an N (neutral) range.

  Although not shown, ECU 300 includes a CPU (Central Processing Unit), a memory, an input / output buffer, and the like. The ECU 300 outputs the engine 100 (fuel injection, ignition timing, throttle opening, etc.) so that the vehicle 1 enters a desired running state based on signals from each sensor and device, and a map and program stored in the memory. ) And the output (energization amount) of the motor generators 10 and 20 are controlled. Various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  When there is a request to start engine 100 while engine 100 is stopped (when fuel supply is stopped), ECU 300 causes PCU 200 (to be described in detail later) so that torque for cranking engine 100 is generated. Inverter 221) is controlled. When engine speed Ne reaches a predetermined value due to cranking, fuel injection control and ignition control of engine 100 are started. Thereby, engine 100 is started.

<Configuration of electrical system and ECU>
FIG. 2 is a circuit block diagram for explaining the configuration of the electric system of the vehicle 1. The electric system of vehicle 1 includes a battery 150, SMR 160, PCU 200, motor generators 10 and 20, and ECU 300. PCU 200 includes a converter 210, a capacitor C <b> 2, inverters 221 and 222, and a voltage sensor 230.

  The battery 150 is provided with a monitoring unit 440. The monitoring unit 440 detects the voltage of the battery 150 (battery voltage) VB, the current flowing through the battery 150 (battery current) IB, and the temperature of the battery 150 (battery temperature) TB, and sends signals indicating the detection results to the ECU 300. Output to.

  Converter 210 includes a capacitor C1, a reactor L1, a switching element Q1 (upper arm) and a switching element Q2 (lower arm), and diodes D1 and D2. Capacitor C1 smoothes battery voltage VB and supplies it to converter 210. Each of switching elements Q1, Q2 and switching elements Q3-Q14 described later are, for example, IGBTs (Insulated Gate Bipolar Transistors). Switching elements Q1, Q2 are connected in series between power line PL and power line NL. Diodes D1 and D2 are connected in antiparallel between the collectors and emitters of switching elements Q1 and Q2, respectively. One end of the reactor L1 is connected to the high potential side of the battery 150. The other end of reactor L1 is connected to an intermediate point between the upper arm and the lower arm (a connection point between the emitter of switching element Q1 and the collector of switching element Q2).

  Converter 210 boosts battery voltage VB input from battery 150 and outputs it to power lines PL and NL by switching operations of the upper arm and the lower arm in accordance with a control signal from ECU 300. Converter 210 steps down DC voltage of power lines PL and NL supplied from one or both of inverter 221 and inverter 222 by switching operation of the upper arm and the lower arm in accordance with a control signal from ECU 300. Output to.

  Capacitor C2 is connected between power line PL and power line NL. Capacitor C <b> 2 smoothes the DC voltage supplied from converter 210 and supplies it to inverters 221 and 222.

  Voltage sensor 230 detects a voltage across capacitor C2, that is, an output voltage (hereinafter also referred to as “system voltage”) VH of converter 210, and outputs a signal indicating the detection result to ECU 300.

  When the system voltage VH is supplied, the inverter 221 drives the motor generator 10 by converting a DC voltage into an AC voltage in accordance with a control signal from the ECU 300. Inverter 221 includes a U-phase arm 1U, a V-phase arm 1V, and a W-phase arm 1W. Each phase arm is connected in parallel between power line PL and power line NL. U-phase arm 1U has switching element Q3 (upper arm) and switching element Q4 (lower arm) connected in series with each other. V-phase arm 1V has switching element Q5 (upper arm) and switching element Q6 (lower arm) connected in series with each other. W-phase arm 1W has switching element Q7 (upper arm) and switching element Q8 (lower arm) connected in series with each other. Diodes D3 to D8 are connected in antiparallel between the collectors and emitters of the switching elements Q3 to Q8, respectively.

  Inverter 222 includes phase arms 2U to 2W, switching elements Q9 to Q14, and diodes D9 to D14. The configuration of inverter 222 is basically the same as the configuration of inverter 221, and therefore description thereof will not be repeated.

  The motor generator 10 is provided with a resolver 421 and a current sensor 241. The motor generator 20 is provided with a resolver 422 and a current sensor 242. Resolver 421 detects the rotational speed of motor generator 10 (MG1 rotational speed Nm1). Resolver 422 detects the rotational speed of motor generator 20 (MG2 rotational speed Nm2). Current sensor 241 detects a current (motor current) IM1 flowing through motor generator 10. Current sensor 242 detects a current (motor current) IM <b> 2 flowing through motor generator 20. Each of these sensors outputs a signal indicating the detection result to ECU 300.

  ECU 300 controls PCU 200 (converter 210 and inverters 221 and 222) based on information from each sensor and the like so that the output of motor generators 10 and 20 becomes a desired output. In the example shown in FIG. 2, ECU 300 is configured as one unit, but ECU 300 may be divided into a plurality of units.

<Normal travel and inverter-less travel>
ECU 300 can cause vehicle 1 to travel in either the normal mode or the retreat mode.

  The normal mode is a mode in which the vehicle 1 travels while switching between the EV travel and the HV travel as necessary. Hereinafter, traveling in the normal mode is referred to as “normal traveling”.

  The evacuation mode is an abnormality in which the motor generators 10 and 20 cannot be normally driven by PWM (Pulse Width Modulation) control of the inverters 221 and 222 (hereinafter, such abnormality is also referred to as “inverter abnormality” for convenience of explanation). Is a mode in which the engine 100 is driven and the vehicle 1 is evacuated while the inverters 221 and 222 are in a gate-blocking state. The inverter abnormality includes failure of sensors such as the resolvers 421 and 422 and current sensors 241 and 242, short-circuit failure of the switching elements Q <b> 3 to Q <b> 14 included in the inverters 221 and 222, open failure, disconnection, and the like. Hereinafter, the traveling in the retreat mode is referred to as “inverter-less traveling”, and the control for performing inverter-less traveling is referred to as “inverter-less traveling control”.

  FIG. 3 is a diagram schematically showing the state of the electrical system when the shift range is the forward range during inverterless travel. During inverterless travel, ECU 300 sets all switching elements Q3 to Q8 included in inverter 221 to a gate cutoff state (non-conductive state). Therefore, a three-phase full-wave rectifier circuit is configured by the diodes D3 to D8 included in the inverter 221. Although not shown in FIG. 3, ECU 300 also puts all switching elements Q9 to Q14 (see FIG. 2) included in inverter 222 into the gate cutoff state.

  Further, when the shift range is the forward range, ECU 300 generates a PWM control signal PWMC for switching each of switching elements Q 1 and Q 2 of switching elements Q 1 and Q 2 of converter 210, and outputs it to converter 210. To do. Thereby, converter 210 enters a switching state by PWM control (hereinafter referred to as “PWM operation state”), and system voltage VH takes a value corresponding to a control signal from ECU 300.

  Further, during the inverterless travel, the engine 100 is in a driving state, and the engine torque Te is output from the engine 100. The motor generator 10 is mechanically rotated by the engine torque Te. Since the motor generator 10 is a synchronous motor, the rotor of the motor generator 10 is provided with a permanent magnet 12. For this reason, when the permanent magnet 12 provided on the rotor of the motor generator 10 is rotated by the engine torque Te, a counter electromotive voltage Vc is generated in the motor generator 10. When the back electromotive voltage Vc exceeds the system voltage VH, a current flows from the motor generator 10 toward the battery 150. At this time, the motor generator 10 generates a counter electromotive torque Tc (braking torque) that acts in a direction that prevents rotation of the motor generator 10.

  FIG. 4 is a diagram illustrating an example of a control state of engine 100 and motor generators 10 and 20 when the shift range is the forward range during inverterless travel. By configuring the planetary gear mechanism 30 as described above, the rotational speed of the sun gear S (= MG1 rotational speed Nm1), the rotational speed of the carrier CA (= engine rotational speed Ne), and the rotational speed of the ring gear R (= The MG2 rotational speed Nm2) has a relationship that is connected by a straight line on the collinear diagram (a relationship that determines the remaining one rotational speed if any two rotational speeds are determined, hereinafter also referred to as a “collinear diagram relationship”). .

  During the inverterless travel, as described above, the motor generator 10 is mechanically rotated by the engine torque Te, so that the motor generator 10 acts in a direction that prevents rotation of the motor generator 10 (negative direction). An electromotive torque Tc is generated.

  When the counter electromotive torque Tc acts on the sun gear S from the motor generator 10, the ring gear R generates a driving torque Tep that acts in the forward direction (forward direction) as a reaction force of the counter electromotive torque Tc. The vehicle 1 is evacuated by this drive torque Tep.

  Note that, since the motor generator 20 is rotated by the drive torque Tep, a counter electromotive voltage is also generated in the motor generator 20. However, in the example shown in FIG. 4, the counter electromotive voltage of the motor generator 20 does not exceed the system voltage VH. Since the MG2 rotational speed Nm2 is decreasing, no counter electromotive torque is generated in the motor generator 20.

  FIG. 5 is a diagram schematically showing the state of the electrical system when the shift range is a non-forward range during inverterless travel. When the shift range is the non-forward range, the ECU 300 puts the inverters 221 and 222 in the gate cutoff state as in the forward range, while the converter 210 is not in the PWM operation state in the forward range but in the gate cutoff state (switching). Element Q1 and Q2 are turned off). Thereby, the current path in the direction from motor generator 10 to battery 150 is blocked by diode D1. As a result, a current flows from motor generator 10 to capacitor C2, while charge transfer from capacitor C2 to capacitor C1 does not occur. Therefore, when system voltage VH increases and system voltage VH reaches back electromotive voltage Vc, no current flows from motor generator 10 to capacitor C2. Therefore, the counter electromotive torque Tc (absolute value) generated by the motor generator 10 is also zero.

  As described above, when the shift range is the non-advanced range during the inverterless travel, the system voltage VH rises to the counter electromotive voltage Vc by setting the converter 210 to the gate cutoff state, and the motor generator 10 to the battery 150. The current going to is cut off. Thereby, the counter electromotive torque Tc is not generated. As a result, the generation of the drive torque Tep can be prevented without stopping the engine 100.

  FIG. 6 is a flowchart showing a processing procedure when ECU 300 performs inverterless travel control. This flowchart is repeatedly executed at a predetermined cycle.

  In step (hereinafter, step is abbreviated as “S”) 10, ECU 300 determines whether or not the above-described inverter abnormality has occurred. If an inverter abnormality has not occurred (NO in S10), ECU 300 sets the control mode to the normal mode and performs normal traveling in S11.

  If an inverter abnormality has occurred (YES in S10), ECU 300 sets the control mode to the evacuation mode and performs inverterless traveling in S12 to S16.

  Specifically, ECU 300 causes inverters 221 and 222 to be in a gate cutoff state in S12, and causes engine 100 to be in a driving state in S13.

  Thereafter, in S14, ECU 300 determines whether or not the shift range is a non-forward range (any one of P range, N range, and R range).

  If the shift range is not the non-forward range (NO in S14), that is, if the shift range is the D range or B range, ECU 300 causes converter 210 to be in the PWM operation state in S15. As a result, as shown in FIGS. 3 and 4, the counter electromotive torque Tc can be generated from the motor generator 10, and the driving torque Tep can be generated on the output shaft 60 as the reaction force.

  On the other hand, when the shift range is the non-forward range (YES in S14), ECU 300 causes converter 210 to be in a gate cutoff state in S16. Thereby, as shown in FIG. 5 described above, the counter electromotive torque Tc can be cut, and therefore the drive torque Tep can be cut without stopping the engine 100.

<Inhibition of increase in MG1 rotation speed Nm1 when switching to the non-forward range>
As described above, when the shift range is the non-advanced range during the inverterless travel, the counter electromotive torque Tc of the motor generator 10 is cut by setting the converter 210 to the gate cutoff state. However, at the time of switching from the forward range to the non-forward range, there is a concern that the MG1 rotational speed Nm1 excessively increases excessively due to the cut of the counter electromotive torque Tc.

  FIG. 7 is a diagram illustrating an example of state changes of the engine 100 and the motor generators 10 and 20 when the shift range is switched from the forward range to the non-forward range during inverterless travel. In FIG. 7, the solid line indicates a collinear diagram in the forward range, and the alternate long and short dash line indicates a collinear diagram when switched to the non-forward range.

  During the forward range, the engine torque Te acts in the positive direction and the motor generator 10 rotates in the forward direction, so that the motor generator 10 generates the counter electromotive torque Tc acting in the negative direction. MG1 rotation speed Nm1 is maintained in a state where engine torque Te (torque that rotates motor generator 10 in the forward direction) and counter electromotive torque Tc (torque that prevents rotation of motor generator 10) are balanced. That is, during the forward range indicated by the solid line, the engine torque Te and the counter electromotive torque Tc are in balance.

  However, when the shift range is switched from the forward range to the non-forward range, converter 210 is turned off, and counter electromotive torque Tc that is balanced with engine torque Te is cut. Therefore, as indicated by the alternate long and short dash line, there is a concern that the MG1 rotation speed Nm1 excessively increases excessively due to the engine torque Te. When the MG1 rotation speed Nm1 is excessively increased, the counter electromotive voltage Vc of the motor generator 10 is excessively increased, and the system voltage VH is excessively increased as the counter electromotive voltage Vc is increased, resulting in an overvoltage state. Concerned.

  In view of the above points, when ECU 300 according to the present embodiment assumes that the current engine torque Te and MG1 rotation speed Nm1 are switched to the non-forward range when the shift range is the forward range during inverterless travel. The predicted value of the MG1 rotational speed Nm1 is calculated, and the engine rotational speed Ne is controlled so that the calculated predicted value of the MG1 rotational speed Nm1 does not exceed the threshold value. Therefore, even when the shift range is switched to the non-forward range, the MG1 rotation speed Nm1 can be suppressed from excessively exceeding the threshold value, and the above-described overvoltage state can be prevented. can do.

  FIG. 8 is a flowchart showing a processing procedure performed by ECU 300 during inverterless traveling. This flowchart is repeatedly executed at a predetermined cycle.

  In S20, ECU 300 determines whether or not the inverter is traveling. When the inverter is not traveling (NO in S20), ECU 300 ends the process.

  If the inverter is traveling (YES in S20), ECU 300 determines in S21 whether the shift range is the forward range (D range or B range).

  When the shift range is the forward range (YES in S21), ECU 300 performs MG1 rotation when it is assumed in S22 that the current engine torque Te and the current MG1 rotational speed Nm1 are switched to the non-forward range. A predicted value of the speed Nm1 is calculated. Specifically, the predicted increase amount ΔN of the MG1 rotational speed Nm1 due to switching to the non-forward range (cutting of the counter electromotive torque Tc by shutting off the gate of the converter 210) is used as the current engine torque Te, engine rotational speed Ne, and MG1 rotational speed. Calculation is made based on the speed Nm1 or the like. Then, a value obtained by adding the calculated predicted increase amount ΔN to the current MG1 rotational speed Nm1 is calculated as a predicted value of the MG1 rotational speed Nm1 when it is assumed that the non-forward range has been switched.

  Note that a value detected by the resolver 421 can be used as the current MG1 rotational speed Nm1. In addition, when the resolver 421 is abnormal, a value calculated from the engine speed Ne and the vehicle speed VS can be used using the relationship of the nomograph.

  In S23, ECU 300 determines whether or not the predicted value of MG1 rotation speed Nm1 calculated in S22 exceeds a threshold value. Here, for example, the threshold value is set to a value at which system voltage VH (back electromotive voltage Vc) is in an overvoltage state after switching to the non-advanced range.

  When the predicted value of MG1 rotational speed Nm1 calculated in S22 does not exceed the threshold value (NO in S23), that is, even if it is switched to the non-advanced range, MG1 rotational speed Nm1 does not exceed the threshold value Is predicted, ECU 300 ends the process.

  If the predicted value of MG1 rotational speed Nm1 calculated in S22 exceeds the threshold value (YES in S23), that is, if the MG1 rotational speed Nm1 exceeds the threshold value if it is switched to the non-forward range. In the case of being performed, the ECU 300 decreases the engine rotation speed Ne by decreasing the engine torque Te. That is, when it is predicted that MG1 rotational speed Nm1 exceeds the threshold value due to switching to the non-forward range, ECU 300 causes MG1 rotational speed Nm1 to exceed the threshold value due to switching to the non-forward range. The engine speed Ne is reduced in advance during the forward range so that there is no occurrence. Thereby, even when the shift range is switched to the non-forward range, it is possible to prevent the MG1 rotation speed Nm1 from exceeding the threshold value and excessively rising.

  As described above, the ECU 300 according to the embodiment of the present invention sets the counter electromotive torque Tc of the motor generator 10 by setting the converter 210 to the gate cutoff state when the shift range is the non-forward range during the inverterless travel. Cut. Thereby, driving torque Tep can be cut while maintaining engine 100 in a driving state. Further, when the shift range is the forward range during the inverterless travel, ECU 300 calculates the predicted value of MG1 rotational speed Nm1 when it is assumed that the current engine torque Te and MG1 rotational speed Nm1 are switched to the non-forward range. The engine speed Ne is calculated so that the calculated predicted value does not exceed the threshold value. Therefore, even when the shift range is switched to the non-forward range, it is possible to prevent the MG1 rotation speed Nm1 from excessively exceeding the threshold value during the forward range. As a result, when the shift range is switched from the forward range to the non-advance range during inverterless travel, the engine 100 is maintained in the drive state and the MG1 rotational speed Nm1 is suppressed from excessively increasing while driving. Generation of torque Tep (forward torque) can be suppressed.

  In the above-described embodiment, the “threshold value” used in S23 of FIG. 8 is determined from the viewpoint of preventing overvoltage of the system voltage VH. However, the method of determining the “threshold value” is not limited to this. For example, the above “threshold value” may be determined from the viewpoint of preventing over-rotation of the pinion gear P or the motor generator 10 of the planetary gear mechanism 30.

  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.

  DESCRIPTION OF SYMBOLS 1 Vehicle, 10, 20 Motor generator, 12 Permanent magnet, 30 Planetary gear mechanism, 50 Drive wheel, 60 Output shaft, 71 Vehicle speed sensor, 100 Engine, 110 Crankshaft, 150 Battery, 160 SMR, 200 PCU, 210 Converter, 221 , 222 Inverter, 230 Voltage sensor, 241, 242 Current sensor, 300 ECU, 410 Engine rotation speed sensor, 421, 422 Resolver, 440 Monitoring unit, 500 Shift lever, 510 Position sensor.

Claims (1)

A hybrid vehicle,
Engine,
A first rotating electric machine having a permanent magnet in the rotor;
An output shaft connected to the drive wheels;
A carrier connected to the engine, a sun gear connected to one of the first rotating electrical machine and the output shaft, and a ring gear connected to the other of the first rotating electrical machine and the output shaft, A planetary gear mechanism that mechanically connects the engine, the first rotating electrical machine, and the output shaft;
A second rotating electrical machine connected to the output shaft;
Battery,
A converter configured to be able to perform voltage conversion between the battery and the power line;
An inverter configured to perform power conversion between the power line, the first rotating electrical machine, and the second rotating electrical machine;
A control device capable of performing inverter-less running control for setting the inverter in a gate cutoff state and driving the engine in a driving state;
While the inverterless travel control is being performed, the control device causes the converter to operate when the shift range of the hybrid vehicle is a forward range, thereby causing torque generated from the first rotating electrical machine to be caused by a counter electromotive voltage. When the shift range is a non-advanced range, the torque caused by the counter electromotive voltage is cut by turning the converter into a gate cutoff state,
When the shift range is the forward range during execution of the inverterless travel control, the control device is switched from the output torque of the engine and the rotational speed of the first rotating electrical machine to the non-forward range. A hybrid vehicle that calculates a predicted value of the rotational speed of the first rotating electrical machine and controls the rotational speed of the engine so that the predicted value of the rotational speed of the first rotating electrical machine does not exceed a threshold value.

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