JP2017056790A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately calculate the rotation speed of a first rotary electric machine even in a case where a resolver abnormality occurs during an inverter-less travel.SOLUTION: First, in a case where resolver abnormality occurs during an inverter-less travel, an ECU, by using a relation of a collinear figure, and by using an output value of an engine revolution speed sensor and that of a wheel speed sensor, calculates: a first estimation value Nm1(VS+) of an MG1 rotation speed, with an assumption that a drive wheel rotates in a forward direction; and a second estimation value Nm1(VS-) of the MG1 rotation speed, with an assumption that the drive wheel rotates in a reverse direction. Further, the ECU calculates a third estimation value Nm1(IB) of the MG1 rotation speed by using a battery current IB from a monitor unit. Then, the ECU sets, as an MG1 rotation speed Nm1, a value closer to the third estimation value Nm1(IB) out of the first estimation value Nm1(VS+) and second estimation value Nm1(VS-).SELECTED DRAWING: 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 Unexamined Patent Publication No. 2013-203116 (Patent Document 1) discloses an engine, a first rotating electrical machine having a permanent magnet in a rotor, an output shaft connected to wheels (drive wheels), a planetary gear mechanism, and an output shaft. A hybrid vehicle is disclosed that includes a second rotating electrical machine connected to the battery, a battery, an inverter that performs power conversion between the battery, the first rotating electrical machine, and the second rotating electrical machine, and a control device. The planetary gear mechanism includes a sun gear connected to the first rotating electric machine, a ring gear connected to the output shaft, and a carrier connected to the engine. The control device performs “inverter-less travel control” that drives the engine and retracts the vehicle while the inverter is in a gate shut-off state when an abnormality occurs in which the first rotating electrical machine and the second rotating electrical machine cannot be controlled normally by the inverter. Run.

  During the inverterless travel control, a counter electromotive voltage is generated in the first rotating electrical machine by mechanically (mechanically) rotating the first rotating electrical machine by the rotational force of the engine. When a current flows from the first rotating electrical machine to the battery by the counter electromotive voltage, a counter electromotive torque (braking torque) that acts in a direction that prevents the rotation of the first rotating electrical machine is generated in the first rotating electrical 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

  The counter electromotive voltage generated by the first rotating electrical machine changes according to the rotational speed of the first rotating electrical machine. Therefore, during the inverterless travel control described above, the counter electromotive torque (that is, drive torque) of the first rotating electrical machine changes according to the rotational speed of the first rotating electrical machine. Therefore, during inverterless travel control, it is desirable to adjust the rotational speed of the first rotating electrical machine so that the counter electromotive torque of the first rotating electrical machine becomes the required torque by controlling the output of the engine. As a premise for that, it is necessary to accurately grasp the rotation speed of the first rotating electrical machine.

  However, during inverterless travel control, for example, a resolver (hereinafter also referred to as “first sensor”) that detects the rotational speed of the first rotating electrical machine and a resolver (hereinafter referred to as “second sensor”) that detects the rotational speed of the second rotating electrical machine. If an abnormality occurs in which the control device cannot obtain the output value (also referred to as “also”), there is a concern that the control device cannot grasp the rotation speed of the first rotating electrical machine.

  The present invention has been made to solve the above-described problem, and the object thereof is even when the control device cannot acquire the output values of the first sensor and the second sensor during inverterless travel control. It is to calculate the rotational speed of the first rotating electrical machine with high accuracy.

  A hybrid vehicle according to the present invention includes an engine, a first rotating electrical machine having a permanent magnet in a rotor, an output shaft connected to wheels, a carrier coupled to the engine, and a sun gear coupled to the first rotating electrical machine. The planetary gear mechanism having a ring gear coupled to the output shaft, the second rotating electrical machine connected to the output shaft, the battery, and the battery, the battery, the first rotating electrical machine, and the second rotating electrical machine can convert power. An inverter, a first sensor capable of detecting the rotational speed and direction of the first rotating electrical machine, a second sensor capable of detecting the rotational speed and rotational direction of the second rotating electrical machine, and an engine capable of detecting the rotational speed of the engine Rotation speed sensor, wheel speed sensor that can detect the rotation speed of the wheel and cannot detect the rotation direction of the wheel, a current sensor that can detect the current flowing through the battery, and inverterless travel And a viable control device control. Inverter-less running control sets the inverter in a gate cut-off state and drives the engine to generate a braking torque caused by a counter electromotive voltage in the first rotating electrical machine. It is the control which runs When the control device cannot acquire the output values of the first sensor and the second sensor during the inverterless travel control, the wheel rotates in the forward direction using the output value of the engine rotational speed sensor and the output value of the wheel speed sensor. A first estimated value of the rotational speed of the first rotating electrical machine when assuming that the wheel is rotating, and a second estimated value of the rotational speed of the first rotating electrical machine when assuming that the wheel is rotating in the reverse direction calculate. The control device calculates a third estimated value of the rotation speed of the first rotating electrical machine using the output value of the current sensor. The control device sets the rotation speed of the first rotating electrical machine to be the one closer to the third estimated value among the first estimated value and the second estimated value.

  According to the above configuration, the engine, the first rotating electrical machine, and the output shaft (the wheel and the second rotating electrical machine) are mechanically connected by the planetary gear mechanism. Therefore, even if the output values of the first sensor and the second sensor cannot be obtained, the collinear relationship of the planetary gear mechanism (the rotational speed of any two of the engine, the first rotating electrical machine, and the output shaft is If it is determined, the remaining one rotational speed is also determined), and the rotational speed of the first rotating electrical machine can be accurately calculated from the rotational speed of the engine and the rotational speed of the wheel (output shaft). However, the wheel speed sensor that detects the rotational speed of the wheel can detect the magnitude (absolute value) of the rotational speed, but cannot detect the rotational direction. Therefore, in the method using the relationship of the nomograph, it is assumed that the rotation speed of the first rotating electrical machine is a value when the wheel is rotated in the forward direction and the wheel is rotated in the reverse direction. Two values are assumed to be the values at the time, and it cannot be determined which value is the actual rotation speed of the first rotating electrical machine.

  On the other hand, during inverterless travel control, the first rotating electrical machine generates a counter electromotive voltage according to the rotation speed of the first rotating electrical machine, and current flows from the first rotating electrical machine to the battery by the counter electromotive voltage. Generates braking torque (back electromotive torque). Therefore, the current flowing through the battery has a value corresponding to the counter electromotive voltage of the first rotating electrical machine, that is, the rotational speed of the first rotating electrical machine. By utilizing this point, it is possible to estimate the rotation speed of the first rotating electrical machine with a certain degree of accuracy using the current flowing through the battery.

  In view of the above points, when the control device cannot acquire the output values of the first sensor and the second sensor during the inverterless travel control, first, the output value of the engine rotation speed sensor is obtained using the relationship of the nomograph. And the output value of the wheel speed sensor, the first estimated value of the rotational speed of the first rotating electrical machine when it is assumed that the wheel is rotating in the forward direction, and the wheel is rotating in the reverse direction A second estimated value of the rotation speed of the first rotating electrical machine when assumed is calculated. Further, the control device calculates a third estimated value of the rotation speed of the first rotating electrical machine using the output value of the current sensor. Then, the control device sets the one closer to the third estimated value among the first estimated value and the second estimated value as the rotation speed of the first rotating electrical machine. In other words, the control device determines which of the first estimated value and the second estimated value calculated using the output values of the speed sensors (engine speed sensor and wheel speed sensor) is the actual rotational speed of the first rotating electrical machine. It is determined using the third estimated value calculated using the output value of the current sensor. Thereby, even if it is a case where the control apparatus cannot acquire the output value of a 1st sensor and a 2nd sensor during inverterless driving | running | working control, the rotational speed of a 1st rotary electric machine can be calculated accurately.

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 the electric system in inverterless driving | running | working. It is a figure which shows roughly the correspondence of MG1 rotational speed Nm1, the counter electromotive voltage Vc, and the counter electromotive torque Tc. It is a figure which shows an example of the control state in inverterless driving | running | working on a nomograph. It is a flowchart (the 1) which shows the process sequence of ECU. It is a figure for demonstrating the calculation method of 1st estimated value Nm1 (VS +) and 2nd estimated value Nm1 (VS-) of MG1 rotational speed by ECU. 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 wheel speed sensor 73, a battery 150, a system main relay (SMR) 160, a high voltage load 170, a power control unit (PCU) 200, and an electronic control unit (ECU: Electronic Control Unit) 300.

  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 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. Further, AC power generated by the motor generator 10 may be supplied to the motor generator 20.

  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 output shaft 60 is connected to the left and right drive wheels 50 via a differential gear.
The drive wheel 50 is provided with a wheel speed sensor 73. Wheel speed sensor 73 detects the rotational speed of drive wheel 50 as wheel speed VS, and outputs a signal indicating the detection result to ECU 300. The wheel speed sensor 73 can detect the magnitude (absolute value) of the rotational speed of the drive wheel 50 but cannot detect the rotational direction of the drive wheel 50. That is, ECU 300 can grasp the magnitude (absolute value) of the rotational speed of drive wheel 50 from the output value of wheel speed sensor 73, but cannot grasp the rotational direction of drive wheel 50. Although one wheel speed sensor 73 is shown in FIG. 1, the number of wheel speed sensors 73 is not limited to one. For example, the wheel speed sensor 73 may be provided on each of four wheels (the left and right drive wheels 50 and the left and right driven wheels (not shown)) of the vehicle 1.

  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.

  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”). . Since the ring gear R is connected to the drive wheel 50 via the output shaft 60, the magnitude (absolute value) of the rotational speed (= MG2 rotational speed Nm2) of the ring gear R is the magnitude (absolute value) of the wheel speed VS. Is proportional to

  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 generators 10 and 20. PCU 200 also converts AC power generated by motor generators 10, 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 high-voltage load 170 is an electric device that is connected to a power line connecting the SMR 160 and the PCU 200 and consumes high-voltage (for example, 200 volts) DC power supplied from the battery 150 or the PCU 200. In FIG. 1, the high-voltage load 170 is shown as one device, but actually includes a plurality of devices. For example, the high-voltage load 170 includes an air conditioner (air conditioner), an in-vehicle AC power source (inverter) that converts DC power into AC 100 V that can use home appliances, and high voltage DC power that is used for auxiliary equipment (for example, 12 DC / DC converter, electric power steering device, etc.

  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, valve timing, etc.) so that the vehicle 1 is in 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 is controlled. Various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

<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 electrical system of vehicle 1 includes a battery 150, an SMR 160, a high voltage load 170, a PCU 200, motor generators 10 and 20, and an 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 a voltage (battery voltage) VB of the battery 150, a current (battery current) IB supplied to the battery 150, and a temperature (battery temperature) TB of the battery 150, and signals indicating the detection results. Is output to the ECU 300.

  The high voltage load 170 is connected to a power line connecting the SMR 160 and the converter 210 of the PCU 200, and is supplied with power from the battery 150 or the converter 210. Current sensor 171 detects a current (load current) Iload supplied from battery 150 or converter 210 to high-voltage load 170 and outputs a signal indicating the detection result to ECU 300.

  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 elements Q3 and Q4 connected in series with each other. V-phase arm 1V has switching elements Q5 and Q6 connected in series with each other. W-phase arm 1W has switching elements Q7 and Q8 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 (first sensor). Resolver 421 detects the rotational speed (MG1 rotational speed Nm1) of motor generator 10, and outputs a signal indicating the detection result to ECU 300. The resolver 421 can detect the magnitude (absolute value) of the rotation speed and the rotation direction. That is, ECU 300 can grasp not only the magnitude (absolute value) of the rotational speed of motor generator 10 but also the rotational direction from the output value of resolver 421.

  The motor generator 20 is provided with a resolver 422 (second sensor). Resolver 422 detects the rotational speed (MG1 rotational speed Nm2) of motor generator 20, and outputs a signal indicating the detection result to ECU 300. Similar to the resolver 421, the resolver 422 can detect the magnitude (absolute value) and rotational direction of the rotational speed. That is, ECU 300 can grasp not only the magnitude (absolute value) of the rotational speed of motor generator 20 but also the rotational direction from the output value of resolver 422.

  Further, motor generators 10 and 20 are provided with current sensors 241 and 242, respectively. 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. In other words, the normal mode is a mode in which the electric drive of the motor generators 10 and 20 by the inverters 221 and 222 is allowed. Hereinafter, traveling in the normal mode is referred to as “normal traveling”.

  In the evacuation mode, an abnormality that prevents the motor generators 10 and 20 from being electrically driven by the inverters 221 and 222 due to failure of components such as the current sensors 241 and 242 (hereinafter also referred to as “inverter abnormality”). In this case, the mode is a mode in which the engine 100 is driven and the vehicle 1 is retracted while the inverters 221 and 222 are in the gate cutoff state. In other words, the evacuation mode is a mode in which the electric drive of the motor generators 10 and 20 by the inverters 221 and 222 is not allowed. 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 during inverterless travel. During inverterless travel, in response to a control signal from ECU 300, all switching elements Q3-Q8 included in inverter 221 are in 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. Similarly, in response to a control signal from ECU 300, all switching elements Q9 to Q14 (see FIG. 2) included in inverter 222 are set in a gate cutoff state (non-conductive state). Therefore, a three-phase full-wave rectifier circuit is configured by diodes D9 to D14 included in inverter 222. On the other hand, in converter 210, switching operations of switching elements Q1, Q2 are continued in response to a control signal from ECU 300.

  During inverterless travel, engine 100 is driven and engine torque Te is output from engine 100. The motor generator 10 is mechanically (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 schematically showing a correspondence relationship between the MG1 rotation speed Nm1, the counter electromotive voltage Vc, and the counter electromotive torque Tc. In FIG. 4, the horizontal axis represents the MG1 rotational speed Nm1, and the vertical axis represents the counter electromotive voltage Vc and the counter electromotive torque Tc in order from the top.

  In the rotation speed region shown in FIG. 4, the counter electromotive voltage Vc has a characteristic that the higher the MG1 rotation speed Nm1, the higher the back electromotive voltage Vc. In the region where MG1 rotation speed Nm1 is lower than predetermined value Nvh, back electromotive voltage Vc is lower than system voltage VH, so that no current flows from motor generator 10 toward battery 150. Therefore, the counter electromotive torque Tc is not generated.

  In the region where MG1 rotational speed Nm1 exceeds predetermined value Nvh, back electromotive voltage Vc exceeds system voltage VH, and therefore, the difference between back electromotive voltage Vc and system voltage VH from motor generator 10 toward battery 150 (hereinafter referred to as “voltage”). A current corresponding to the difference ΔV ”flows. That is, motor generator 10 generates a counter electromotive force, and battery 150 is charged with the counter electromotive force. At this time, a counter electromotive torque Tc corresponding to the voltage difference ΔV is generated in the motor generator 10. Back electromotive torque Tc is a braking torque (negative torque) that acts in a direction that prevents rotation of motor generator 10.

  FIG. 5 is a diagram illustrating an example of a control state of engine 100 and motor generators 10 and 20 during inverterless traveling on the alignment chart of 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 (= MG2 rotational speed Nm2) are collinear. In the figure, there is a relationship connected by a straight line (a relationship of collinear diagrams).

  During inverterless travel, engine torque Te is output from engine 100. When the motor generator 10 is dynamically rotated by the engine torque Te, the motor generator 10 generates a counter electromotive voltage Vc. When counter electromotive voltage Vc exceeds system voltage VH, motor generator 10 generates counter electromotive torque Tc that acts in a direction (negative direction) that prevents rotation of motor generator 10.

  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.

  Although 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. 5, 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. 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 S14.

  Specifically, ECU 300 causes inverters 221 and 222 to be in a gate cutoff state in S12. Thereafter, in S13, ECU 300 controls converter 210 such that system voltage VH becomes target system voltage VHtag. In the present embodiment, target system voltage VHtag can be set to a predetermined fixed value, for example.

  Thereafter, ECU 300 drives engine 100 in S14. That is, ECU 300 generates counter electromotive torque Tc from motor generator 10 by driving engine 100 and mechanically rotating motor generator 10. At this time, by controlling the output of engine 100, MG1 rotation speed Nm1 is adjusted so that counter electromotive torque Tc of motor generator 10 becomes a torque according to the user's request. As a result, the vehicle 1 is retreated by the drive torque Tep acting on the output shaft 60 as a reaction force of the counter electromotive torque Tc.

<Calculation of MG1 rotational speed Nm1 during inverterless travel>
During the inverterless travel described above, by controlling the output of engine 100, MG1 rotational speed Nm1 is adjusted so that counter electromotive torque Tc of motor generator 10 becomes a torque according to the user's request. Therefore, ECU 300 needs to accurately grasp MG1 rotation speed Nm1.

  However, when there is an abnormality that prevents the ECU 300 from acquiring the output values of the resolver 421 and 422 (hereinafter also referred to as “resolver abnormality”) due to a failure of the resolver 421 and 422 or the like during the inverterless traveling, the MG1 rotational speed Nm1 is grasped. There is concern that you will not be able to.

  Therefore, ECU 300 according to the present embodiment calculates MG1 rotation speed Nm1 by the following method when a resolver abnormality occurs during inverterless travel.

  In the vehicle 1 described above, the engine 100, the motor generator 10, and the output shaft 60 (the drive wheels 50 and the motor generator 20) are mechanically connected by the planetary gear mechanism 30. Therefore, even when the resolver abnormality occurs, the output value of the engine rotation speed sensor 410 (engine rotation speed Ne) and the output of the wheel speed sensor 73 are utilized using the nomographic relationship of the planetary gear mechanism 30. From the value (wheel speed VS), the MG1 rotation speed Nm1 can be accurately calculated.

  However, the wheel speed sensor 73 can detect the magnitude (absolute value) of the rotational speed of the drive wheel 50 but cannot detect the rotational direction of the drive wheel 50. Therefore, in the method using the relationship of the nomograph, the value when the driving wheel 50 is assumed to rotate in the forward direction (positive direction) and the driving wheel 50 in the backward direction (negative) as the MG1 rotational speed Nm1. Two values are assumed, which are assumed to be rotating in the direction), and it is not possible to specify which value is the actual MG1 rotation speed Nm1.

  On the other hand, during inverterless travel control, motor generator 10 generates a counter electromotive voltage Vc corresponding to MG1 rotation speed Nm1, and the counter electromotive voltage Vc causes a back electromotive force to flow from motor generator 10 to battery 150. Torque Tc is generated. Therefore, battery current IB has a value corresponding to counter electromotive voltage Vc of motor generator 10, that is, MG1 rotation speed Nm1. By using this point, it is possible to estimate the MG1 rotation speed Nm1 with a certain degree of accuracy using the battery current IB from the monitoring unit 440.

  In view of the above points, when a resolver abnormality occurs during inverterless travel, ECU 300 first uses the relationship of the nomograph to output the output value of engine speed sensor 410 and the output value of wheel speed sensor 73. And the first estimated value Nm1 (VS +) of the MG1 rotational speed when it is assumed that the drive wheel 50 is rotating in the forward direction (positive direction), and the drive wheel 50 is in the reverse direction (negative direction). A second estimated value Nm1 (VS−) of the MG1 rotation speed when it is assumed to be rotating is calculated.

  FIG. 7 is a diagram for explaining a method of calculating the first estimated value Nm1 (VS +) and the second estimated value Nm1 (VS−) by the ECU 300. The ECU 300 first determines the MG2 rotational speed estimated value Nm2 (VS +) when the driving wheel 50 is rotating in the forward direction from the output value (wheel speed VS) of the wheel speed sensor 73, and the driving wheel 50. MG2 rotational speed estimated value Nm2 (VS−) when it is assumed that is rotating in the reverse direction. Here, the estimated value Nm2 (VS +) and the estimated value Nm2 (VS−) have the same absolute value, and the signs are opposite (Nm2 (VS +)> 0, Nm2 (VS −) <0).

  Further, the ECU 300 calculates the first estimated value Nm1 (VS +) described above using the engine speed Ne and the estimated value Nm2 (VS +) using the relationship of the nomograph (see the one-dot chain line in FIG. 7). ). Similarly, the ECU 300 calculates the second estimated value Nm1 (VS−) described above using the engine rotational speed Ne and the estimated value Nm2 (VS−) using the relationship of the nomograph (FIG. 7). (See two-dot chain line) As illustrated in FIG. 7, the first estimated value Nm1 (VS +) and the second estimated value Nm1 (VS−) are different values, and it cannot be specified which value is the actual MG1 rotational speed Nm1. .

  Therefore, ECU 300 calculates third estimated value Nm1 (IB) of MG1 rotation speed using battery current IB from monitoring unit 440. Then, ECU 300 determines which one of first estimated value Nm1 (VS +) and second estimated value Nm1 (VS-) is actual MG1 rotational speed Nm1 using third estimated value Nm1 (IB). . Specifically, among the first estimated value Nm1 (VS +) and the second estimated value Nm1 (VS−), the one closer to the third estimated value Nm1 (IB) is set as the MG1 rotation speed Nm1. Thereby, even when the resolver abnormality occurs during the inverterless travel, the MG1 rotation speed Nm1 can be calculated with high accuracy.

  FIG. 8 is a flowchart showing a processing procedure when ECU 300 calculates MG1 rotation speed Nm1. This flowchart is repeatedly executed at a predetermined cycle during the inverterless travel.

  In S20, ECU 300 determines whether or not the above-described resolver abnormality (abnormality in which ECU 300 cannot obtain the output value of resolver 421 or 422 due to a failure of resolver 421 or 422) has occurred. If resolver abnormality has not occurred (NO in S20), ECU 300 ends the process.

  When resolver abnormality has occurred (YES in S20), ECU 300 assumes in S21 that drive wheel 50 is rotating in the forward direction from the output value (wheel speed VS) of wheel speed sensor 73. MG2 rotational speed estimated value Nm2 (VS +) and MG2 rotational speed estimated value Nm2 (VS-) when it is assumed that the driving wheel 50 is rotating in the reverse direction are calculated. As described above, the estimated value Nm2 (VS +) and the estimated value Nm2 (VS−) have the same absolute value, and the signs are opposite (Nm2 (VS +)> 0, Nm2 (VS −) <0).

  In S22, ECU 300 uses the relationship of the nomograph to drive using the output value of engine rotation speed sensor 410 (engine rotation speed Ne) and estimated value Nm2 (VS +) calculated in S21. A first estimated value Nm1 (VS +) of the MG1 rotation speed when it is assumed that the wheel 50 is rotating in the forward direction is calculated.

  In S23, using the relationship of the nomograph, ECU 300 uses the output value (engine speed Ne) of engine speed sensor 410 and estimated value Nm2 (VS−) calculated in S21. A second estimated value Nm1 (VS−) of the MG1 rotation speed when the driving wheel 50 is assumed to be rotating in the reverse direction is calculated.

  In S24, ECU 300 calculates third estimated value Nm1 (IB) of MG1 rotation speed using battery current IB from monitoring unit 440. For example, ECU 300 calculates third estimated value Nm1 (IB) by the following method.

  During inverterless travel, the current generated by the electric power generated by the motor generator 10 is supplied to the battery 150 and the high voltage load 170, so that the electrical relationship shown in the following equation (1) is established.

IB + Iload = 2π × Nm1 × Tc / (60 × VB) (1)
In equation (1), the battery current IB and the battery voltage VB can be acquired from the monitoring unit 440. The load current Iload can be acquired from the current sensor 171. The load current Iload can also be estimated from the state of each device of the high-voltage load 170. Therefore, the equation (1) includes two unknowns, the MG1 rotation speed Nm1 (unit: rpm) and the counter electromotive torque Tc. However, the relationship shown in FIG. 4 is established between the MG1 rotational speed Nm1 and the counter electromotive torque Tc. Therefore, ECU 300 calculates third estimated value Nm1 (IB) of MG1 rotation speed based on battery current IB by using the relationship of equation (1) and the relationship shown in FIG.

  In S25, ECU 300 determines that the absolute value (= | Nm1 (VS +) − Nm1 (IB) |) of the difference between first estimated value Nm1 (VS +) and third estimated value Nm1 (IB) is the second estimated value. It is determined whether or not the absolute value (= | Nm1 (VS −) − Nm1 (IB) |) of the difference between Nm1 (VS−) and the third estimated value Nm1 (IB) is smaller. This determination is a process of determining whether or not the first estimated value Nm1 (VS +) is closer to the third estimated value Nm1 (IB) than the second estimated value Nm1 (VS−).

  When | Nm1 (VS +) − Nm1 (IB) | is smaller than | Nm1 (VS −) − Nm1 (IB) | (YES in S25), that is, first estimated value Nm1 (VS +) is second estimated value Nm1. When closer to the third estimated value Nm1 (IB) than (VS−), the ECU 300 treats the first estimated value Nm1 (VS +) as the MG1 rotational speed Nm1.

  When | Nm1 (VS +) − Nm1 (IB) | is larger than | Nm1 (VS −) − Nm1 (IB) | (NO in S25), that is, second estimated value Nm1 (VS−) is the first estimated value. When it is closer to the third estimated value Nm1 (IB) than Nm1 (VS +), the ECU 300 treats the second estimated value Nm1 (VS−) as the MG1 rotational speed Nm1.

  As described above, when the resolver abnormality occurs during the inverterless travel, ECU 300 according to the present embodiment first uses the relationship between the nomographs and the output value of engine rotation speed sensor 410 and the wheel speed sensor. Using the output value 73, the first estimated value Nm1 (VS +) of the MG1 rotation speed when the drive wheel 50 is assumed to be rotating in the forward direction and the drive wheel 50 are rotated in the reverse direction. And a second estimated value Nm1 (VS−) of the MG1 rotation speed is calculated. Further, ECU 300 uses battery current IB from monitoring unit 440 to calculate third estimated value Nm1 (IB) of MG1 rotation speed. Then, ECU 300 sets MG1 rotation speed Nm1 as a value closer to third estimated value Nm1 (IB) among first estimated value Nm1 (VS +) and second estimated value Nm1 (VS−). Thereby, even when the resolver abnormality occurs during the inverterless travel, the MG1 rotation speed Nm1 can be calculated with high accuracy.

  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, 73 Wheel speed sensor, 100 Engine, 110 Crankshaft, 150 Battery, 170 High-pressure load, 171, 241, 242 Current sensor, 200 PCU, 210 converter, 221, 222 inverter, 230 voltage sensor, 300 ECU, 410 engine speed sensor, 421, 422 resolver, 440 monitoring unit.

Claims (1)

Engine,
A first rotating electric machine having a permanent magnet in the rotor;
An output shaft connected to the wheels;
A planetary gear mechanism having a carrier coupled to the engine, a sun gear coupled to the first rotating electrical machine, and a ring gear coupled to the output shaft;
A second rotating electrical machine connected to the output shaft;
Battery,
An inverter capable of converting power between the battery, the first rotating electrical machine and the second rotating electrical machine;
A first sensor capable of detecting a rotation speed and a rotation direction of the first rotating electrical machine;
A second sensor capable of detecting a rotation speed and a rotation direction of the second rotating electrical machine;
An engine rotation speed sensor capable of detecting the rotation speed of the engine;
A wheel speed sensor capable of detecting the rotation speed of the wheel and not detecting the rotation direction of the wheel;
A current sensor capable of detecting a current flowing through the battery;
And a control device capable of executing inverter-less travel control,
In the inverterless running control, the inverter is turned off and the engine is driven to generate a braking torque caused by a counter electromotive voltage in the first rotating electrical machine, and the output shaft is used as a reaction force of the braking torque. Is a control to drive the vehicle with torque acting on the
When the control device cannot obtain the output values of the first sensor and the second sensor during the inverterless travel control,
Using the output value of the engine rotational speed sensor and the output value of the wheel speed sensor, a first estimated value of the rotational speed of the first rotating electrical machine when it is assumed that the wheel is rotating in the forward direction; Calculating a second estimated value of the rotation speed of the first rotating electrical machine when it is assumed that the wheel is rotating in the reverse direction;
Calculating a third estimated value of the rotation speed of the first rotating electrical machine using the output value of the current sensor;
A hybrid vehicle, wherein the first estimated value and the second estimated value that are closer to the third estimated value are set as the rotation speed of the first rotating electrical machine.

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