JP2011088549A - Power output device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power output device which does not incur the risk, that a power conversion unit is damaged due to the reverse electromotive voltage of a motor, without degrading fuel consumption or raising cost. <P>SOLUTION: When a motor temperature T detected by a motor temperature sensor 10 is less than a predeterminedd temperature Tth, a power transmitter 1 is controlled so that a reverse electromotive voltage which may be generated by a motor at a motor temperature T will become less than a withstand voltage limit of a PDU6. The power transmitter 1 is controlled so that a motor rotational speed N will become less than an upper limit rotational speed Nlim according to a motor temperature T. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power output apparatus including an internal combustion engine and an electric motor.

  A power output apparatus for a hybrid vehicle including an internal combustion engine and an electric motor is known. This power output device drives an internal combustion engine to output power, boosts a DC voltage from a DC power source with a step-up / step-down unit (converter), and then converts it into AC DC with a power conversion unit (inverter). The AC motor (electric motor) is driven by the converted AC voltage to output power.

  The AC motor generates a counter electromotive voltage (induced voltage) corresponding to the rotation speed, and this counter electromotive force is applied to the power conversion unit. However, if a counter electromotive voltage exceeding the withstand voltage limit is applied, the power conversion unit may be damaged. The counter electromotive voltage of an AC motor is temperature dependent and increases as the motor temperature decreases. Therefore, conventionally, a power conversion unit having a large withstand voltage limit has been used so as not to be damaged by a counter electromotive voltage even at an extremely low temperature.

  In Patent Document 1, an upper limit value of the applied voltage applied to the inverter by the converter is set based on the temperature dependence of the switching element included in the inverter and the temperature detection result of the inverter, and the upper limit value is exceeded. It is disclosed to control the converter so that it does not.

JP 2008-167616 A

  However, when a power conversion unit having a large withstand pressure limit is used as in the conventional case, there is a problem in that fuel efficiency is reduced due to power loss in the power conversion unit and the cost of the conversion unit increases.

  The present invention has been made in view of such a background, and an object thereof is to provide a power output device in which there is no possibility that the power conversion unit is damaged by the counter electromotive voltage of the electric motor without causing a reduction in fuel consumption or an increase in cost. To do.

  The present invention includes a power transmission device that transmits power of an internal combustion engine and an electric motor to a drive shaft, a power conversion device that performs power conversion between the electric motor and a power storage device, and a temperature detection unit that detects a temperature of the electric motor. A power output device including a control unit that controls the power transmission device, wherein when the temperature detected by the temperature detection means is less than a predetermined temperature, the control unit causes the motor to move at the detected temperature. The power transmission device is controlled so that a counter electromotive voltage that can be generated is less than a withstand voltage limit of the power conversion device.

  According to the present invention, when the temperature of the electric motor is lower than the predetermined temperature, the counter electromotive voltage that can be generated by the electric motor is less than the withstand voltage limit of the power converter. It is known that the withstand voltage characteristic of a power conversion device generally decreases as the temperature increases, and the temperature of the power conversion device is greatly affected by the temperature of the motor. Therefore, by setting the temperature of the electric motor at which the maximum counter electromotive voltage that can be generated by the electric motor does not exceed the withstand voltage limit of the power converter to the predetermined temperature, it is possible that the power converter may be damaged by the counter electromotive voltage. Can be prevented.

  Furthermore, by using a power conversion device having a withstand voltage limit such that the predetermined temperature is a normal temperature, for example, about 0 ° C., electric power having a large withstand voltage limit exceeding the back electromotive force that can be generated by the electric motor at an extremely low temperature. There is no need to use a converter. Therefore, compared to the conventional case, it is possible to improve fuel efficiency and reduce the cost of the power converter by reducing power loss in the power converter. If the predetermined temperature is a normal temperature, for example, about 0 degree, it can be reached immediately after starting even at an extremely low temperature.

  In the present invention, when the temperature detected by the temperature detecting means is less than the predetermined temperature, the control unit causes the power so that the rotational speed of the electric motor is less than the rotational speed corresponding to the detected temperature. It is preferable that the back electromotive voltage that can be generated by the electric motor at the detected temperature is less than the withstand voltage limit of the power converter by controlling the transmission device.

  In this case, when the motor temperature is lower than the predetermined temperature, by limiting the number of rotations of the motor to less than the number of rotations according to the temperature of the motor, a back electromotive voltage that can be generated by the motor at that temperature is converted into a power converter. It is less than the withstand pressure limit. Therefore, it is possible to reliably prevent the power converter from being damaged by the counter electromotive voltage by simple control that limits the upper limit of the rotation speed of the electric motor.

  In the present invention, when the temperature of the motor is lower than the predetermined temperature, it is not necessary to control the back electromotive voltage that can be generated by the motor to be lower than the withstand voltage limit of the power converter by promoting the temperature rise of the motor. A normal state is preferable.

  Therefore, in the present invention, the power transmission device includes a medium circulation unit that circulates a medium that exchanges heat with the electric motor, and when the temperature detected by the temperature detection unit is lower than the predetermined temperature, the control unit Preferably, the medium circulating means is controlled so as to increase the circulation amount of the medium.

  In this case, when the temperature of the electric motor is lower than the predetermined temperature, the circulation amount of the medium circulated by the medium circulation means increases. Therefore, it is possible to promote the temperature rise of the electric motor.

  In the present invention, when the temperature detected by the temperature detecting means is less than the predetermined temperature, the control unit determines that the back electromotive voltage that can be generated by the electric motor at the detected temperature is a withstand voltage of the power converter. It is preferable to control the power converter so that the current flowing through the electric motor is maximized under a condition that is less than the limit.

  In this case, when the temperature of the electric motor is lower than the predetermined temperature, the current flowing through the electric motor becomes maximum under the condition that the back electromotive voltage that can be generated by the electric motor at the temperature is lower than the withstand voltage limit of the power converter. Therefore, it is possible to promote the temperature rise of the electric motor.

  In the present invention, when the temperature detected by the temperature detecting means is less than the predetermined temperature, the control unit determines that the back electromotive voltage that can be generated by the electric motor at the detected temperature is a withstand voltage of the power converter. It is preferable to control the power converter so that the output of the electric motor is maximized under a condition that is less than the limit.

  In this case, when the temperature of the electric motor is lower than the predetermined temperature, the output of the electric motor becomes maximum under the condition that the counter electromotive voltage that can be generated by the electric motor at the temperature is lower than the withstand voltage limit of the power converter. Therefore, it is possible to promote the temperature rise of the electric motor.

  Furthermore, in the present invention, the power transmission device includes a first power transmission path that transmits power from the internal combustion engine and the electric motor to the drive shaft, and a second power transmission that transmits power from the internal combustion engine to the drive shaft. A first connecting / disconnecting means capable of connecting / disconnecting the internal combustion engine and the first power transmission path, and a second connecting / disconnecting means capable of connecting / disconnecting the internal combustion engine and the second power transmission path. When the temperature detected by the temperature detecting means is lower than the predetermined temperature, the control unit connects the internal combustion engine to the first power transmission path by the first connecting / disconnecting means, and the second disconnecting means. It is preferable to control the power transmission device so that the internal combustion engine is connected to the second power transmission path by contact means.

  In this case, when the temperature of the electric motor is lower than the predetermined temperature, the internal combustion engine is connected to the first power transmission path and the internal combustion engine is connected to the second power transmission path. As a result, the power of the internal combustion engine is divided and transmitted to the drive shaft, so that it is transmitted to the drive shaft via the first power transmission path as compared with the case where the internal combustion engine is connected only to the first power transmission path. The power of the internal combustion engine is reduced. As a result, the power of the internal combustion engine transmitted to the electric motor via the first power transmission path is reduced, so that the rotational speed of the electric motor can be reduced.

  In addition, the temperature detection unit may directly measure the temperature of the electric motor, estimate the temperature of the electric motor from a measurement value obtained by measuring the temperature of another device in the vicinity of the electric motor, or the refrigerant that cools the electric motor. What is necessary is just to detect the temperature of the said motor by either estimating the temperature of the said motor from the measured value which measured temperature, or estimating the temperature of the said motor from progress of the operating state of the said motor.

1 is an overall configuration diagram of a power output apparatus according to an embodiment of the present invention. Schematic block diagram of PDU. The functional block diagram of ECU. (A) is a graph showing the relationship between the motor temperature and the counter electromotive voltage, (b) is a graph showing the relationship between the motor rotational speed and the counter electromotive voltage, and (c) is a graph showing the relationship between the motor temperature and the motor upper limit rotational speed. The flowchart explaining operation | movement of a power output device.

  A power output apparatus according to an embodiment of the present invention will be described with reference to the drawings. This power output apparatus is suitably mounted on a hybrid vehicle. First, the configuration of the power output apparatus will be described.

  As shown in FIG. 1, the power output device includes a power transmission device 1 and includes an engine 2 and a motor (motor / generator) 3 as power generation sources. The engine 2 corresponds to the internal combustion engine in the present invention, and the motor 3 corresponds to the electric motor in the present invention.

  The power transmission device 1 is configured to be able to drive the axle 4 by transmitting the power (driving force, torque) of the engine 2 and / or the motor 3 to the axle 4 which is a driven part. The power transmission device 1 is configured to transmit power from the engine 2 and / or power from the axle 4 to the motor 3 so that the motor 3 can perform a regenerative operation. The axle 4 corresponds to the drive shaft in the present invention.

  Further, the power transmission device 1 is configured such that the auxiliary machine 5 mounted on the vehicle can be driven by the power of the engine 2 and / or the motor 3. The auxiliary machine 5 is, for example, an air conditioner compressor, a water pump, an oil pump, or the like.

  The engine 2 is an internal combustion engine that generates power by burning fuel such as gasoline, light oil, and alcohol. The engine 2 has a driving force input shaft 2 a for inputting generated power to the power transmission device 1. The engine 2 controls the power of the engine 2 by controlling the opening degree of a throttle valve (not shown) provided in an intake passage (not shown) in the same manner as a normal automobile engine. The

  The motor 3 is an AC motor, more specifically, a three-phase DC brushless motor. The motor 3 includes a hollow rotor (rotating body) 3a that is rotatably supported in a housing (not shown) provided in a stationary part that is stationary with respect to the vehicle body, such as an outer case of the power transmission device 1, and a stator (stator). ) 3b. The rotor 3a is provided with a plurality of permanent magnets. The stator 3b is provided with coils (armature windings) 3ba for three phases (U phase, V phase, W phase). The stator 3b is fixed to the housing.

  As shown in FIG. 2, the coil 3ba is connected to a battery (DC power supply, secondary battery) 7 that is a power storage device via a power drive unit (hereinafter referred to as “PDU”) 6 that is a drive circuit of the motor 3. Is electrically connected. The PDU 6 is electrically connected to an electronic control unit (hereinafter referred to as “ECU”) 8. The PDU 6 corresponds to the power converter in the present invention, and the ECU 8 corresponds to the control unit in the present invention.

  As shown in FIG. 3, ECU8 is electrically connected to each component of vehicles other than PDU6, such as the power transmission device 1, the engine 2, and the motor 3, and controls these each component. The ECU 8 of the present embodiment is an electronic circuit unit that includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), an interface circuit, and the like.

  The ECU 8 executes a control process defined by the program based on signals received from the driving force request unit 9, the motor temperature sensor 10, and the various sensor sensors 11. The function of the ECU 8 will be described later.

  The driving force requesting unit 9 sends a driving force request signal for setting the driving force required for the axle 4 to the EPU 8 based on, for example, the driver's operation or traveling state. The driving force setting unit 9 includes, for example, an accelerator sensor that detects the depression amount of the accelerator pedal, a brake sensor that detects the depression amount of the brake pedal, a throttle opening sensor that detects the throttle opening degree, and the like.

  The motor temperature sensor 10 measures the temperature T of the motor 3 (hereinafter referred to as “motor temperature”) T and sends a signal indicating the measurement result to the ECU 8. The motor temperature sensor 10 of this embodiment measures the temperature of the rotor 3a provided with a permanent magnet as the motor temperature T.

  The various sensors 11 are, for example, a shift position sensor that detects a shift position of a shift lever (not shown), a vehicle speed sensor that detects the speed of the vehicle, an acceleration sensor that detects the acceleration of the vehicle, and an engine that detects the rotational speed of the engine 2. It consists of a rotation speed sensor, a vehicle speed sensor such as a shift speed sensor that detects the state of various clutches and synchronizers in the power transmission device 1, an acceleration sensor, an engine rotation speed sensor, a shift speed detection sensor, and the like, and shows detection results by each sensor. A signal is sent to the ECU 8.

  Further, the ECU 8 is also electrically connected to the medium circulation unit 12. The medium circulation unit 12 is configured such that the ECU 8 can control the medium circulation amount (medium circulation amount per unit time) so as to maintain the motor temperature T within an appropriate range.

  The medium circulation unit 12 includes, for example, a circulation path that passes through the adjacent portion or the vicinity of the motor 3, a pump that circulates the medium in the circulation path, a heat exchanger that performs heat exchange with the medium in the circulation path, and the temperature of the medium. It has a temperature sensor to measure. The medium circulation unit 12 raises or cools the motor 3 by heat exchange between the medium circulating in the circulation path and the motor 3. As a medium, fluids such as oil and water, and gases such as air can be used. However, lubricating and operating oil (ATF: Automatic transmission fluid) of the power transmission device 1 and cooling water (radiator of the radiator) for cooling the engine 2 can be used. It is preferable to use (cooling water). Thereby, the medium circulation unit 12 can be configured relatively easily.

  Next, the configuration of the power transmission device 1 according to the present embodiment will be described. As shown in FIG. 1, the power transmission device 1 includes a power combining mechanism 13 that combines the power of the engine 2 and the power of the motor 3. As the power combining mechanism 13, a planetary gear device is employed in this embodiment. The power combining mechanism 13 will be described later.

  A first main input shaft 14 is connected to the driving force input shaft 2 a of the engine 2. The first main input shaft 14 is disposed in parallel to the driving force input shaft 2a, and power from the engine 2 is input via a first clutch C1 serving as first connecting / disconnecting means. The first main input shaft 14 extends from the engine 2 side to the motor 3 side. The first main input shaft 14 is configured to be connected to and disconnected from the driving force input shaft 2a of the engine 2 by the first clutch C1. The first main input shaft 14 is connected to the rotor 3 a of the motor 3.

  The first clutch C <b> 1 is configured to be able to connect and disconnect the driving force input shaft 2 a and the first main input shaft 14 under the control of the ECU 8. When the driving force input shaft 2a and the first main input shaft 14 are connected by the first clutch C1, power can be transmitted between the driving force input shaft 2a and the first main input shaft 14. Further, when the connection between the driving force input shaft 2a and the first main input shaft 14 is disconnected by the first clutch C1, the power transmission is interrupted between the driving force input shaft 2a and the first main input shaft 14. .

  A first sub input shaft 15 is coaxially arranged with respect to the first main input shaft 14. The first auxiliary input shaft 15 is configured to be able to be connected to and disconnected from the driving force input shaft 2a of the engine 2 by a second clutch C2 that is a second connecting / disconnecting means.

  The second clutch C <b> 2 is configured to be able to connect and disconnect between the driving force input shaft 2 a and the first sub input shaft 15 under the control of the ECU 8. When the driving force input shaft 2a and the first auxiliary input shaft 15 are connected by the second clutch C2, power transmission between the driving force input shaft 2a and the first auxiliary input shaft 15 becomes possible. Further, when the connection between the driving force input shaft 2a and the first auxiliary input shaft 15 is disconnected by the second clutch C2, power transmission is interrupted between the driving force input shaft 2a and the first auxiliary input shaft 15. . The first clutch C1 and the second clutch C2 are disposed adjacent to the first main input shaft 14 in the axial direction. The first clutch C1 and the second clutch C2 of the present embodiment are constituted by wet multi-plate clutches.

  As described above, in the power transmission device 1, the first clutch C1 transmits the rotation of the driving force input shaft 2a to the first main input shaft 14 in a releasable manner, and the second clutch C2 rotates the driving force input shaft 2a. Is removably transmitted to the second main input shaft 22.

  A reverse shaft 16 is disposed in parallel to the first main input shaft 14. A reverse gear shaft 17 is rotatably supported on the reverse shaft 16. The first main input shaft 14 and the reverse gear shaft 17 are always coupled via a gear train 18. The gear train 18 is configured by meshing a gear 14 a fixed on the first main input shaft 14 and a gear 17 a provided on the reverse gear shaft 17. The reverse shaft 16 is provided with a reverse gear 17c fixed on the reverse gear shaft 17 and a reverse synchronization device SR which can switch connection and disconnection with the reverse shaft 16.

  An intermediate shaft 19 is arranged with respect to the reverse shaft 16 and in parallel with the first main input shaft 14. The intermediate shaft 19 and the reverse shaft 16 are always connected via a gear train 20. The gear train 20 is configured by meshing a gear 19 a fixed on the intermediate shaft 19 and a gear 16 a fixed on the reverse shaft 16. The intermediate shaft 19 and the first auxiliary input shaft 15 are always connected via a gear train 21. The gear train 21 is configured by meshing a gear 19 a fixed on the intermediate shaft 19 and a gear 15 a fixed on the first auxiliary input shaft 15.

  A second main input shaft 22 is arranged parallel to the first main input shaft 14 with respect to the intermediate shaft 19. The second main input shaft 22 and the intermediate shaft 19 are always connected via a gear train 23. The gear train 23 is configured by meshing a gear 19 a fixed on the intermediate shaft 19 and a gear 22 a fixed on the second main input shaft 22.

  The first main input shaft 14 has gears of odd-numbered or even-numbered gears (odd-numbered third and fifth gears in this embodiment) among the plurality of gears having different gear ratios. The row drive gears are rotatably supported and connected to the motor 3. Specifically, the second sub input shaft 24 is coaxially disposed with respect to the first main input shaft 14. The second sub input shaft 24 is disposed closer to the motor 3 than the first sub input shaft 15. The first main input shaft 14 and the second sub input shaft 24 are connected via the first synchronous meshing mechanism S1.

  The first synchronous meshing mechanism S1 is provided on the first main input shaft 14, and selectively connects the third speed gear 24a and the fifth speed gear 24b to the first main input shaft 14. Specifically, the first synchronous meshing mechanism S1 is a well-known one such as a synchro clutch, and by moving the sleeve S1a along the axial direction of the second sub input shaft 24 by an actuator and a shift fork (not shown), The third speed gear 24 a and the fifth speed gear 24 b are selectively connected to the first main input shaft 14. Specifically, when the sleeve S1a moves from the illustrated neutral position to the third speed gear 24a side, the third speed gear 24a and the first main input shaft 14 are connected. On the other hand, when the sleeve S1a moves from the illustrated neutral position to the fifth speed gear 24b side, the fifth speed gear 24b and the first main input shaft 14 are connected.

  The second main input shaft 22 has gears of even-numbered or odd-numbered gears (even-numbered 2nd gear and 4th gear in this embodiment) among a plurality of gears having different gear ratios. The drive gear of the row is supported rotatably. Specifically, the third sub input shaft 25 is coaxially arranged with respect to the second main input shaft 22. The second main input shaft 22 and the third sub input shaft 25 are connected via a second synchronous meshing mechanism S2.

  The second synchromesh mechanism S2 is provided on the second main input shaft 22, and is configured to selectively connect the second speed gear 25a and the fourth speed gear 25b to the second main input shaft 22. The second synchromesh mechanism S2 is a well-known one such as a synchro clutch, and the second-speed gears 25a and 4 are moved by moving the sleeve S2a in the axial direction of the third auxiliary input shaft 25 by an actuator and shift fork (not shown). The speed gear 25 b is selectively connected to the second main input shaft 22. When the sleeve S2a moves from the illustrated neutral position to the second speed gear 25a side, the second speed gear 25a and the second main input shaft 22 are connected. On the other hand, when the sleeve S2a moves from the illustrated neutral position to the fourth speed gear 25b side, the fourth speed gear 25b and the second main input shaft 22 are connected.

  The third sub input shaft 25 and the output shaft 26 are coupled via a second speed gear train 27. The second gear train 27 is configured by meshing a gear 25 a fixed on the third sub input shaft 25 and a gear 26 a fixed on the output shaft 26. Further, the third sub input shaft 25 and the output shaft 26 are coupled via a fourth speed gear train 28. The fourth speed gear train 28 is configured by meshing a gear 25 b fixed on the third sub input shaft 25 and a gear 26 b fixed on the output shaft 26.

  The output shaft 26 and the second auxiliary input shaft 24 are coupled via a third speed gear train 29. The third speed gear train 29 is configured by meshing a gear 26 a fixed to the output shaft 26 and a gear 24 a fixed to the second auxiliary input shaft 24. The output shaft 26 and the second auxiliary input shaft 24 are coupled via a fifth speed gear train 30. The fifth speed gear train 30 is configured by meshing a gear 26b fixed to the output shaft 26 and a gear 24b fixed on the second sub input shaft 24. The gears 26a and 26b of each gear train fixed to the output shaft 26 are referred to as driven gears.

  A final gear 26 c is fixed to the output shaft 26. The rotation of the output shaft 26 is configured to be transmitted to the drive wheels 32 via the final gear 26 c, the differential gear unit 31, and the axle 4.

  The input shaft 5 a of the auxiliary machine 5 is arranged in parallel to the reverse shaft 16. The reverse shaft 16 and the input shaft 5a of the auxiliary machine 5 are coupled via, for example, a belt mechanism 34. The belt mechanism 34 is configured by connecting a gear 17b fixed on the reverse gear shaft 17 and a gear 5b fixed on the input shaft 5a via a belt. An auxiliary machine clutch 35 is interposed on the input shaft 5 a of the auxiliary machine 5. The gear 5b and the input shaft 5a of the auxiliary machine 5 are connected coaxially through an auxiliary machine clutch 35.

  The auxiliary device clutch 35 is a clutch that operates so as to connect or disconnect between the gear 5 b and the input shaft 5 a of the auxiliary device 5 under the control of the ECU 8. In this case, when the auxiliary machine clutch 35 is operated in the connected state, the gear 5b and the input shaft 5a of the auxiliary machine 5 are coupled via the auxiliary machine clutch 35 so as to rotate integrally with each other. Further, when the auxiliary machine clutch 35 is operated in the disconnected state, the coupling between the gear 5b and the input shaft 5a of the auxiliary machine 5 by the auxiliary machine clutch 35 is released. In this state, power transmission to the first main input shaft 14 and the input shaft 5a of the auxiliary machine 5 is interrupted.

  Next, the power combining mechanism 13 will be described. The power combining mechanism 13 is provided inside the motor 3. Specifically, a part or all of the rotor 3a, the stator 3b, and the coil 3ba constituting the motor 3 are overlapped with the power combining mechanism 13 along a direction orthogonal to the axial direction of the first main input shaft 14. Has been placed.

  The power combining mechanism 13 includes a differential device that can differentially rotate the first rotating element, the second rotating element, and the third rotating element. In the present embodiment, the differential gear that constitutes the power combining mechanism 13 is a single pinion type planetary gear device. As the three rotary elements, a sun gear (first rotary element) 13s and a ring gear (second rotary element) are used. Between the sun gear 13s and the ring gear 13r, a carrier (third rotating element) 13c that rotatably supports a plurality of planetary gears 13p meshed with the sun gear 13s and the ring gear 13r is provided coaxially. These three rotating elements 13s, 13r, and 13c can transmit power between each other, and rotate while maintaining a constant collinear relationship between the respective rotational speeds (rotational speeds).

  The sun gear 13 s is fixed to one end of the first main input shaft 14 on the motor 3 side so as to rotate in conjunction with the first main input shaft 14. The sun gear 13s is fixed to the rotor 3a so as to rotate in conjunction with the rotor 3a of the motor 3. Thereby, the sun gear 13s, the first main input shaft 14, and the rotor 3a rotate in unison with each other.

  The ring gear 13r is configured to be switchable between a fixed state and a non-fixed state with respect to the housing 33, which is a non-moving portion, by the third synchronous meshing mechanism SL. Specifically, by moving the sleeve SLa of the third synchronous meshing mechanism SL along the rotation axis direction of the ring gear 13r, the housing 33 and the ring gear 13r can be switched between a fixed state and an unfixed state. It is configured.

  The carrier 13 c is fixed to one end of the second sub input shaft 24 on the motor 3 side so as to rotate in conjunction with the second sub input shaft 24.

  In the power transmission device 1 configured as described above, the first transmission path in the present invention includes the first main input shaft 14, the second sub input shaft 24, the third speed gear train 29 (or the fifth speed gear train 30), and It comprises an output shaft 26 and the like. The second transmission path in the present invention includes the first sub input shaft 15, the gear train 21, the second main input shaft 22, the second speed gear train 27 (or the fourth speed gear train 28), the output shaft 26, and the like. The

  Next, the gear position in the power transmission device 1 of the present embodiment will be described. As described above, the power transmission device 1 is configured to shift the rotational speed of the input shaft to a plurality of stages through the gear trains of a plurality of shift stages having different speed ratios and to output to the axle 4. In the power transmission device 1, it is defined that the gear ratio is smaller as the gear position is larger.

  When the engine is started, the first clutch C1 is connected, the motor 3 is driven, and the engine 2 is started. That is, the motor 3 also has a function as an engine starter.

  The first gear is established by bringing the ring gear 13r and the housing 33 into a connected state (fixed state) by the third synchronous meshing mechanism SL. When traveling by the engine 2, the second clutch C2 is disengaged (hereinafter referred to as “OFF state”), and the first clutch C1 is engaged (hereinafter referred to as “ON state”). The driving force output from the engine 2 is transmitted to the axle 4 through the sun gear 13s, the carrier 13c, the gear train 29, the output shaft 26, and the like.

  If the motor 3 is driven as well as the engine 2 is driven, the assist travel by the motor 3 at the first speed (travel that assists the driving force of the engine 2 by the motor 3) can be performed. Furthermore, if the first clutch C1 is in the OFF state, EV traveling that travels only by the motor 3 can be performed.

  Further, during the deceleration regenerative operation, the motor 3 is braked to generate power by the motor 3 being braked, and the battery 7 can be charged via the PDU 6.

  In the second gear, the ring gear 13r and the housing 33 are unfixed by the third synchronous mesh mechanism SL, and the second synchronous mesh mechanism S2 is connected to the second main input shaft 22 and the second gear 25a. It is established by that. When traveling by the engine 2, the second clutch C2 is turned on. In the second speed, the driving force output from the engine 2 is the first main input shaft 14, the gear train 21, the intermediate shaft 19, the gear train 23, the second main input shaft 22, the gear train 27, the output shaft 26, and the like. Is transmitted to the axle 4 via.

  If the first clutch C1 is turned on to drive the engine 2 and the motor 3, the assist travel by the motor 3 at the second gear can be performed. Furthermore, in this state, driving by the engine 2 can be stopped and EV traveling can be performed. When stopping the driving by the engine 2, for example, the engine 2 may be in a fuel cut state or a cylinder resting state. Further, the decelerating regenerative operation can be performed at the second speed stage.

  When the first clutch C1 is in the OFF state, the second clutch C2 is in the ON state, and the ECU 8 is traveling at the second speed by driving the engine 2, the ECU 8 is predicted to upshift to the third speed depending on the traveling state of the vehicle. If the determination is made, the first synchronous meshing mechanism S1 sets the first main input shaft 14 and the third speed gear 24a in a connected state or a pre-shifted state approaching this state. As a result, the upshift from the second gear to the third gear can be performed smoothly.

  The third speed is established by bringing the first synchronous meshing mechanism S1 into a state where the first main input shaft 14 and the third speed gear 24a are connected. When traveling by the engine 2, the first clutch C1 is turned on. At the third speed, the driving force output from the engine 2 is transmitted to the axle 4 via the first main input shaft 14, the third gear train 29, the output shaft 26, and the like.

  If the first clutch C1 is turned on to drive the engine 2 and the motor 3, the assist travel by the motor 3 at the third speed can be performed. Furthermore, the EV clutch can be performed with the first clutch C1 in the OFF state. Note that during EV traveling, the first clutch C1 can be turned on to stop driving by the engine 2, and EV traveling can be performed. Further, the decelerating regenerative operation can be performed at the third speed stage.

  During traveling at the third gear, the ECU 8 predicts whether the next gear to be shifted is the second gear or the fourth gear based on the traveling state of the vehicle. When the ECU 8 predicts a downshift to the second speed, the second synchronous meshing mechanism S2 is connected to the second speed gear 25a and the second main input shaft 22, or a preshift state close to this state. To do. When the ECU 8 predicts an upshift to the fourth speed, the second synchromesh mechanism S2 is connected to the fourth speed gear 25b and the second main input shaft 22, or a preshift state close to this state. To do. Thereby, the upshift and the downshift from the third gear can be performed smoothly.

  The fourth speed is established by bringing the second synchronous meshing mechanism S2 into a state where the second main input shaft 22 and the fourth speed gear 25b are connected. When traveling by the engine 2, the second clutch C2 is turned on. In the fourth speed, the driving force output from the engine 2 is transmitted through the first main input shaft 14, the gear train 21, the intermediate shaft 19, the gear train 23, the second main input shaft 22, the output shaft 26, and the like. 4 is transmitted.

  If the second clutch C2 is turned on, the first clutch C1 is turned on, the engine 2 is driven and the motor 3 is driven, the assist travel by the motor 3 at the fourth speed can be performed. Furthermore, in this state, driving by the engine 2 can be stopped and EV traveling can be performed.

  The second clutch C2 is turned off, the first clutch C1 is turned on, and the ECU 8 is driven at the fourth speed by driving the engine 2, and the ECU 8 is next shifted based on the running state of the vehicle. Predict whether it is 3rd gear or 5th gear. When the ECU 8 predicts a downshift to the third speed, the first main engagement shaft 14 and the third speed gear 24a are connected by the first synchronous meshing mechanism S1, or the preshift state in which the first main input shaft 14 is brought close to this state. And When the ECU 8 predicts an upshift to the fifth speed stage, the first main engagement shaft S1 and the fifth speed gear 24b are connected by the first synchronous meshing mechanism S1, or a preshift state in which the first main input shaft 14 is brought close to this state. And Thereby, the upshift and the downshift from the fourth gear can be performed smoothly.

  The fifth speed is established by bringing the first synchronous meshing mechanism S1 into a state where the first main input shaft 14 and the fifth speed gear 24b are connected. When traveling by the engine 2, the first clutch C1 is turned on. At the fifth speed, the driving force output from the engine 2 is transmitted to the axle 4 through the first main input shaft 14, the third gear train 29, the output shaft 26, and the like.

  In addition, if the 1st clutch C1 is made into ON state, the engine 2 is driven, and the motor 3 is driven, the assist driving | running | working by the motor 3 in 5th speed stage can also be performed. Furthermore, the EV clutch can be performed with the first clutch C1 in the OFF state. Further, the EV clutch can be performed by turning on the first clutch C1 and stopping the driving by the engine 2. Further, the decelerating regenerative operation can be performed at the fifth gear.

  When the ECU 8 determines that the next gear to be shifted is the fourth gear based on the traveling state of the vehicle while traveling at the fifth gear, the ECU 8 sets the second synchromesh mechanism S2 to 4 A state in which the speed gear 25b and the second main input shaft 22 are connected to each other, or a pre-shift state close to this state is set. Thereby, the downshift from the fifth gear to the fourth gear can be performed smoothly.

  In the reverse gear, the reverse synchronous meshing mechanism SR is connected to the reverse shaft 16 and the reverse gear 17c, and the second synchronous meshing mechanism S2 is connected to, for example, the second main input shaft 22 and the second speed gear 25a. It is established by setting it to the state. When traveling by the engine 2, the first clutch C1 is turned on. In this reverse speed, the driving force output from the engine 2 is the first main input shaft 14, the gear train 18, the reverse gear 17c, the reverse shaft 16, the gear train 20, the intermediate shaft 19, the gear train 23, the second main input. It is transmitted to the axle 4 via the shaft 22, the third auxiliary input shaft 25, the gear train 27, the output shaft 26, and the like. In addition, if the engine 3 is driven and the motor 3 is driven, assist traveling by the motor 3 in the reverse speed can be performed. Furthermore, EV traveling can also be performed by setting the first clutch C1 to the OFF state. Deceleration regenerative operation can be performed in the reverse gear.

  Next, the configuration of the PDU 6 of this embodiment will be described with reference to FIG.

  The PDU 6 is a power conversion unit that performs power conversion between the motor 3 and the battery 7 via a step-up / step-down unit (converter) 41 that increases or decreases a DC voltage. The PDU 6 includes an inverter circuit 42 that performs power conversion between AC power and DC power, and a smoothing capacitor 43 that smoothes a DC voltage from the step-up / down unit 41 and supplies the DC voltage to the inverter circuit 42. Although not shown in detail, the step-up / step-down unit 41 includes a switching element, a diode, a reactor, and the like, and steps up or down a DC voltage.

  During EV travel or assist travel, the step-up / step-down unit 41 boosts the DC voltage supplied from the battery 7, and the inverter circuit 42 converts the boosted DC voltage into an AC voltage to drive and control the motor 3. On the other hand, during regenerative travel, the inverter circuit 42 converts AC power generated by the motor 3 into DC power, and the DC power is stepped down by the step-up / down unit 41 and charged to the battery 7.

  The inverter circuit 42 includes three arms (U-phase arm, V-phase arm, and W-phase arm) 44 provided to correspond to the coils 3ba of the respective phases of the motor 3. Each arm 44 includes a pair of switching units 45 each including a switching element 45a that performs a switching operation and a diode 45b that is connected in parallel to the switching element 45a. The switching element 45a is a power semiconductor element, for example, an IGBT (Insulated Gate Bipolar Transistor).

  Next, functions of the ECU 8 of the present embodiment will be described with reference to FIG.

  The ECU 8 includes a hybrid control unit 8a, a power transmission control unit 8b, an engine control unit 8c, a PDU control unit 8d, a step-up / down control unit 8e, a medium circulation control unit 8f, and a storage unit 8g as means for realizing the functions in the present invention. Prepare.

  The hybrid control unit 8a is configured such that the motor temperature T measured by the motor temperature sensor 10, the various detected values detected by the various sensors 11, the battery 7 so that the driving force requested from the driving force requesting unit 9 is output to the axle 4. Travel mode (engine travel mode, EV travel mode, assist travel mode, or regenerative travel mode), engine based on the vehicle state such as the charging amount of the vehicle, the medium temperature measured by the temperature sensor of the medium circulation unit 12, and the vehicle speed. 2, various settings such as the number of rotations of 2, the voltage applied to the motor 3, the gear position, and the medium circulation amount in the medium circulation unit 12 are determined.

  The power transmission control unit 8b controls the power transmission device 1 in accordance with the travel mode, the gear position, and the like determined by the hybrid control unit 8a. Specifically, the power transmission control unit 8b controls the power transmission device 1 through an actuator or a drive circuit (not shown) for the operations of the sleeves of the various clutches C1, C2 and the various synchronization devices S1, S2, SL, SR. To do.

  The engine control unit 8c controls the engine 2 according to settings such as the travel mode determined by the hybrid control unit 8a and the rotation speed of the engine 2. Specifically, the engine control unit 8c controls the engine 2 via an engine control actuator such as a throttle valve actuator (not shown).

  The PDU control unit 8d controls the PDU 6 in accordance with the travel mode determined by the hybrid control unit 8a, the voltage applied to the motor 3, and the like. Specifically, the PDU control unit 8d controls the current flowing through the coil 3ba via the PDU 6, and adjusts the power (torque) output from the rotor 3a by the motor 3. In this case, by controlling the PDU 6, the motor 3 performs a power running operation that generates a power running torque in the rotor 3 a with the electric power supplied from the battery 7, and functions as a motor. That is, the electric power supplied to the stator 3b is converted into power by the rotor 3a and output. Further, by controlling the PDU 6, the motor 3 performs a regenerative operation for generating regenerative torque in the rotor 3 a while generating electric power by the rotational energy given to the rotor 3 a and charging the battery 7. That is, the motor 3 also functions as a generator. In this case, the power input to the rotor 3a is converted into electric power by the stator 3b.

  The step-up / step-down control unit 8e controls the step-up / step-down unit 12 in accordance with the travel mode determined by the hybrid control unit 8a, the voltage applied to the motor 3, and the like.

  The medium circulation control unit 8f controls the medium circulation unit 12 according to the setting of the medium circulation amount or the like in the medium circulation unit 12 determined by the hybrid control unit 8a. Specifically, the medium circulation control unit 8e adjusts the medium circulation amount by controlling the pump output and the like of the medium circulation unit 12.

  By the way, the motor 3 generates a counter electromotive voltage (induced voltage) V corresponding to its rotation speed (hereinafter referred to as “motor rotation speed”) N. As shown in FIG. 4A, the counter electromotive voltage V has temperature dependence, and increases as the motor temperature T decreases. Therefore, for example, a large back electromotive voltage V can be applied to the PDU 6 when the outside air temperature is a low temperature of 0 ° C. or less, particularly an extremely low temperature such as −40 ° C. If the back electromotive voltage V exceeds the withstand voltage limit Vi of the PDU 6, the PDU 6 may be damaged. Note that the withstand voltage limit Vi of the PDU 6 depends on the withstand voltage limits of the switching element 45 a and the smoothing capacitor 46.

  As shown in FIG. 4B, the counter electromotive voltage V generated by the motor 3 is proportional to the motor rotation speed N, and becomes maximum when the motor rotation speed N is the maximum rotation speed Nmax. Further, it is known from experimental results and the like that the withstand voltage characteristic of the PDU 6 generally becomes lower as the temperature becomes higher, and the temperature of the PDU 6 is greatly influenced by the motor temperature T. Therefore, as shown in FIG. 4A, if the motor temperature T is equal to or higher than the temperature Tth, the counter electromotive voltage V does not exceed the withstand voltage limit Vi of the PDU 6, and thus the PDU 6 may be damaged by the counter electromotive voltage. Disappear. Note that the maximum rotation speed Nmax of the motor 3 is a rotation speed at which the motor 3 can rotate without damage when the load on the rotation of the motor 3 is minimized, and is an eigenvalue depending on the structure and connection of the motor 3. .

  On the other hand, when the motor temperature T is lower than the temperature Tth, the PDU 6 may be damaged by the counter electromotive voltage V depending on the motor rotation speed N. Therefore, it is necessary to reliably suppress the counter electromotive voltage V that can be generated by the motor 3 to be less than the withstand voltage limit Vi of the PDU 6. Here, referring to FIG. 4B, for example, when the motor temperature T is -40 degrees, which is a very low temperature, if the motor rotation speed N is limited to less than the rotation speed Nth, the back electromotive force V becomes the withstand voltage limit of the PDU6. Vi will not be exceeded. Therefore, as shown in FIG. 4C, when the motor temperature T is −40 degrees, the rotation speed Nth is set as the upper limit rotation speed Nmax of the motor 3.

  In this embodiment, since the rotor 3a of the motor 3 rotates integrally with the first main input shaft 14 via the sun gear 13s, the motor rotation speed N is equal to the rotation speed of the first main input shaft 14. Will be equal.

  As shown in FIG. 4 (c), the hybrid controller 8a of the present embodiment has a motor temperature T that prevents the PDU 6 from being damaged even if the counter electromotive voltage V of the motor 3 is applied. When the temperature is lower than the predetermined temperature Tth, an upper limit rotational speed Nlim of the motor rotational speed N corresponding to the motor temperature T (or the rotational speed of the first main input shaft 14 equal to this) is set. The upper limit rotational speed Nlim may be obtained by searching or the like from a table stored in advance in the storage unit 8g based on the motor temperature T.

  A plurality of maps (not shown) for setting the various settings based on the vehicle state are stored in advance in the storage unit 8g of the ECU 8, and the motor temperature T detected by the motor temperature sensor 10 is equal to or higher than the predetermined temperature Tth. Depending on whether or not, the map read from the storage unit 8g may be different. In this case, the map that is read when the motor temperature T is equal to or higher than the predetermined temperature Tth is a map for normal travel, and the map that is read when the motor temperature T is lower than the predetermined temperature Tth is the motor rotation speed with respect to the normal travel map. FIG. 6 is a map for limited travel that is modified so that an upper limit rotational speed Nlim of N is limited according to the motor temperature T; The map for normal travel is a map in which the upper limit rotational speed Nlim of the motor rotational speed N is set constant at the maximum rotational speed Nmax regardless of the motor temperature T.

  For example, in the map for limited travel, when the rotational speed of the first main input shaft 14 exceeds the upper limit rotational speed Nlim in normal engine travel or assist travel at the first speed, the second clutch C2 is turned on. The second main input shaft 22 is connected to the second speed gear 25a or the fourth speed gear 25b by the second synchronous meshing mechanism S2, so that the rotation speed of the first main input shaft 14 is less than the upper limit rotation speed Nlim. Set to suppress.

  The predetermined temperature Tth is a relatively low temperature, for example, 0 degrees or at most about 20 degrees, and the motor temperature T exceeds the temperature Tth immediately after starting. For this reason, even if the motor rotation speed N is limited so as not to exceed the upper limit rotation speed Nlim for a short time after starting, the influence on usability is small.

  Further, when the motor temperature T is lower than the predetermined temperature Tth, the hybrid control unit 8a causes the power transmission device 1, the engine 2, and the motor to promote the increase of the motor temperature T via the control units 8b to 8e. 3 and the medium circulation unit 12 are preferably controlled. As a result, it is possible to quickly return to normal running without the limitation of the motor rotation speed N. Such a setting that promotes the increase in the motor temperature T may be included in the map.

  In order to promote the temperature increase of the motor 3, for example, the hybrid control unit 8a may control the medium circulation unit 12 via the medium circulation control unit 8e so that the medium circulation amount is increased as compared with the normal travel time.

  Further, in order to promote the temperature rise of the motor 3, the hybrid control unit 8a may control the PDU 6 via the PDU control unit 8d so that the current flowing through the motor 3 is larger than that during normal travel.

  In order to accelerate the temperature rise of the motor 3, the hybrid control unit 8a may control the PDU 6 via the PDU 6 so that the required driving force is derived from the power of the motor 3 as much as possible. That is, when the required driving force can be output only with the power of the motor 3 below the motor upper limit rotational speed Nlim, the engine 2 is stopped via the engine control unit 8c. However, when the required driving force is not satisfied with the power that can be output by the motor 3 with the motor lower limit rotation speed Nlim, the engine 2 is controlled via the engine control unit 8c so that the insufficient driving force is output to the engine 2. To do.

  Next, the operation of the power output apparatus according to the present embodiment will be described with reference to FIG. The following operations are executed by the control units 8a to 8f of the ECU 8.

  In step ST <b> 1, the hybrid control unit 8 a acquires a signal indicating the motor temperature T from the motor temperature sensor 10. In step ST2, the hybrid control unit 8a determines whether the motor temperature T is equal to or higher than a predetermined temperature Tth based on the signal. If it is determined that the motor temperature T is equal to or higher than the predetermined temperature Tth, the process proceeds to step ST3. Otherwise, the process proceeds to step ST4.

  In step ST3, the hybrid control unit 8a reads from the storage unit 8g a map for normal travel that does not need to limit the motor rotation speed N, and based on this map, the power transmission device is passed through the control units 8b to 8f. 1. The engine 2, the motor 3, the PDU 6 and the medium circulation unit 12 are controlled, and the process returns to step ST1.

  In step ST4, the hybrid control unit 8a reads a map for limiting travel that limits the motor rotational speed N to the upper limit rotational speed Nlim from the storage unit 8g, and based on this map, the power is transmitted via the control units 8b to 8f. Control of the transmission device 1, the engine 2, the motor 3, the PDU 6 and the medium circulation unit 12 is performed. Furthermore, the hybrid control unit 8a promotes an increase in the motor temperature T via the control units 8b to 8f. Then, the process returns to step ST1.

  As described above, in the power output apparatus according to the present embodiment, when the motor temperature T measured by the motor temperature sensor 10 is lower than the temperature Tth (ST2: NO), the motor rotation speed N corresponds to the motor temperature T. Limited travel is performed so as to be less than the upper limit rotational speed Nlim. Therefore, the counter electromotive voltage that can be generated by the motor 3 is less than the withstand voltage limit Vi of the PDU 6, and there is no possibility that the PDU 6 is damaged by the counter electromotive voltage of the motor 3. Further, the temperature Tth is a normal temperature that is not extremely low, for example, about 0 ° C., and is at least a temperature that can be reached immediately after starting, so that there is little inconvenience due to the limited travel.

  Further, a PDU 6 having a withstand voltage limit Vi such that the temperature Tth is not a very low temperature, for example, about 0 ° C. can be used, and a large withstand voltage limit exceeding the counter electromotive force of the motor 3 that can be generated at an extremely low temperature. It is not necessary to use a PDU 6 having Therefore, compared to the conventional case, it is possible to reduce power loss in the PDU 6 and improve fuel efficiency, and it is possible to reduce costs. Generally, the withstand voltage limit Vi of the PDU 6 depends on the withstand voltage limit of the switching element 45a, but the standard switch element 45a has a wide range of withstand voltage specifications. For this reason, conventionally, a switch element having an unnecessarily large withstand voltage limit has been employed under normal temperature, but it is not necessary to employ such a switch element.

  As mentioned above, although the power output device which concerns on embodiment of this invention was demonstrated, this invention is not limited to this embodiment.

  For example, the configuration of the power transmission device is not limited to the power transmission device 1 of the present embodiment. The power transmission device in the present invention may be any power transmission device that transmits the power of the internal combustion engine and the electric motor to the drive shaft. For example, when a power transmission device in which an output shaft (driving force input shaft 2a) of an internal combustion engine and a rotating shaft of an electric motor (motor) are directly connected is provided, the motor temperature T measured by the motor temperature sensor 10 is less than the temperature Tth In some cases, the engine 2 may be controlled such that the engine speed is less than the upper limit speed Nlim corresponding to the motor temperature T.

  In the present embodiment, the case where the motor temperature T is directly detected by the motor temperature sensor 10 has been described. However, the present invention is not limited to this, and the motor temperature T may be indirectly detected such that the motor temperature T is estimated by calculation based on the progress of the operation parameters of the motor 3. Examples of the operation parameters of the motor 3 include a motor rotation speed N, a voltage applied to the motor 3, an engine rotation speed, a gear position, a vehicle speed, and an outside air temperature. Further, for example, a map that associates the progress of the operation parameter with the motor temperature T is stored in the storage unit 8g in advance, and the motor temperature T is detected from the map read from the storage unit 8g based on the progress of the operation parameter. May be.

  Furthermore, a temperature sensor is provided which is located in an adjacent portion or a vicinity of the motor 3 and measures the temperature of a device / equipment whose temperature is affected by a change in the temperature of the motor 3. The temperature change may be detected indirectly. For example, a temperature sensor that measures the temperature of the medium circulating in the circulation path of the medium circulation unit 12 may be provided.

  In the present embodiment, the case where the step-up / step-down unit 41 that increases or decreases the DC voltage is provided between the PDU 6 and the battery 7 has been described. However, the present invention is not limited to this, and when it is not necessary to perform step-up / step-down between the PDU 6 and the battery 7, it is not necessary to provide the step-up / down unit 41.

 Moreover, the case where the permanent magnet was provided in the rotor 3a of the motor 3 was demonstrated. However, the present invention is not limited to this, and a permanent magnet may be provided on the stator 3b. In this case, the motor temperature sensor 10 preferably detects the temperature of the stator 3b.

  DESCRIPTION OF SYMBOLS 1 ... Power transmission device, 2 ... Engine (internal combustion engine: ENG), 2a ... Driving force input shaft, 3 ... Motor (electric motor), 3a ... Rotor, 3b ... Stator, 4 ... Axle (drive shaft), 6 ... Power Drive unit (PDU, power conversion unit, power conversion device), 7 ... Battery (power storage device, secondary battery), 8 ... Electronic control unit (ECU, control unit), 8a ... Hybrid control unit, 8b ... Power transmission control , 8c: engine control unit, 8d: PDU control unit, 8e: step-up / down pressure control unit, 8f: medium circulation control unit, 8g: storage unit, 9: driving force request unit, 10: motor temperature sensor (temperature detection means) , 12 ... Medium circulation unit (medium circulation device), 13 ... Power combining mechanism (planetary gear device), 13c ... Carrier, 13p ... Planetary gear, 13r ... Ring gear, 13s ... Sun gear, 14 ... First main Force axis, 15 ... first sub input shaft, 19 ... intermediate shaft, 20 ... gear train, 21 ... gear train, 22 ... second main input shaft, 24 ... second sub input shaft, 25 ... third sub input shaft, 26 ... output shaft, 26a, 26b ... driven gear, 27 ... 2nd gear train, 28 ... 4th gear train, 29 ... 3rd gear train, 30 ... 5th gear train, 31 ... differential gear unit, C1 ... first 1 clutch (first connection / disconnection means), C2... Second clutch (second connection / disconnection means), S1... First synchronization engagement mechanism, S2... Second synchronization engagement mechanism, SL.

Claims (7)

A power transmission device that transmits power of the internal combustion engine and the motor to a drive shaft; a power conversion device that performs power conversion between the motor and the power storage device; temperature detection means that detects a temperature of the motor; and the power transmission. A power output device comprising a control unit for controlling the device,
When the temperature detected by the temperature detecting means is less than a predetermined temperature, the control unit is configured so that a back electromotive voltage that can be generated by the electric motor at the detected temperature is less than a withstand voltage limit of the power converter. A power output device that controls a power transmission device.   When the temperature detected by the temperature detection means is less than the predetermined temperature, the control unit controls the power transmission device so that the rotation speed of the electric motor is less than the rotation speed corresponding to the detected temperature. The power output apparatus according to claim 1, wherein a counter electromotive voltage that can be generated by the electric motor under the detected temperature is less than a withstand voltage limit of the power converter. The power transmission device includes medium circulation means for circulating a medium that exchanges heat with the electric motor,
The control unit controls the medium circulation unit to increase the circulation amount of the medium when the temperature detected by the temperature detection unit is lower than the predetermined temperature. The power output device described in 1.   When the temperature detected by the temperature detecting means is lower than the predetermined temperature, the control unit is configured to satisfy a condition that a back electromotive voltage that can be generated by the electric motor at the detected temperature is lower than a withstand voltage limit of the power converter. The power output device according to any one of claims 1 to 3, wherein the power conversion device is controlled so that a current flowing through the electric motor is maximized.   When the temperature detected by the temperature detecting means is lower than the predetermined temperature, the control unit is configured to satisfy a condition that a back electromotive voltage that can be generated by the electric motor at the detected temperature is lower than a withstand voltage limit of the power converter. The power output device according to any one of claims 1 to 4, wherein the power conversion device is controlled so that the output of the electric motor is maximized. The power transmission device is
A first power transmission path for transmitting power from the internal combustion engine and the electric motor to the drive shaft;
A second power transmission path for transmitting power from the internal combustion engine to the drive shaft;
First connecting / disconnecting means capable of connecting / disconnecting the internal combustion engine and the first power transmission path;
Second connection / disconnection means capable of connecting / disconnecting the internal combustion engine and the second power transmission path;
When the temperature detected by the temperature detecting means is lower than the predetermined temperature, the control unit connects the internal combustion engine to the first power transmission path by the first connecting / disconnecting means, and the second connecting / disconnecting means. 6. The power output device according to claim 1, wherein the power transmission device is controlled so as to connect the internal combustion engine to the second power transmission path.   The temperature detection means directly measures the temperature of the motor, estimates the temperature of the motor from a measured value of the temperature of another device in the vicinity of the motor, or measures the temperature of the refrigerant that cools the motor. The temperature of the electric motor is detected by either estimating the temperature of the electric motor from a measured value or estimating the temperature of the electric motor from the progress of the operating state of the electric motor. The power output device according to any one of the above.

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