JP4924257B2 - Vehicle and temperature raising method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle which suppresses a back electromotive voltage generated in a motor which drives wheels by using an electromagnetic force generated by a permanent magnet, irrespective of an external temperature environment. <P>SOLUTION: A brake disc 500 is fastened to a drive shaft 2 and a wheel hub 220, and generates a friction force between brake pads 530 which are driven by a brake calliper 510. When it is required to warm motor generators MGL, MGR, an ECU outputs a control command BRL so that prescribed friction heat is generated. The friction heat is generated from the brake disc 500 by the friction force, and the motor generators MGL, MGR are warmed by the convection (heat flow) of the heat generated in the brake disc 500. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a vehicle equipped with an electric motor that drives a wheel using electromagnetic force generated by a permanent magnet, and more particularly, to a technique for reducing an influence associated with a magnetizing action at a low temperature.

  In recent years, electric vehicles such as hybrid vehicles and electric vehicles have attracted a great deal of attention as environmentally friendly vehicles. Such an electric vehicle includes a power storage device including a secondary battery and an electric motor that receives electric power from the power storage device and generates a driving force. Such an electric motor generates a driving force when starting or accelerating, and converts the kinetic energy of the vehicle into electric energy and recovers it to the power storage device during braking or the like.

  Therefore, as a motor mounted on an electric vehicle, a permanent magnet synchronous machine is often used from the viewpoints of high density of field magnetic flux and ease of power regeneration. In particular, an interior permanent magnet synchronous machine with an embedded structure that can be used for torque generation in combination with drive torque (reluctance torque) generated by the asymmetry of the magnetic resistance is often employed.

  In general, the holding force of the permanent magnet decreases as the temperature decreases, while the magnetic flux density of the permanent magnet itself increases as the temperature decreases. Therefore, the counter electromotive voltage generated by the rotation of the electric motor tends to increase as the temperature decreases even at the same rotation speed. As a result, when the temperature is low, there is a possibility that a back electromotive voltage exceeding the dielectric strength of a drive circuit (in particular, a switching element) for driving the electric motor may be generated.

Therefore, Japanese Patent Laid-Open No. 2005-45927 (Patent Document 1) discloses a driving circuit that prevents an electric load exceeding a breakdown tolerance from being applied to a driving circuit due to an induced voltage (counterelectromotive voltage) associated with motor rotation. A motor drive system is sometimes disclosed that includes control means for controlling the rotational speed of the motor.
JP 2005-45927 A JP 2005-127406 A JP 2004-166341 A JP 2005-341701 A

  By the way, in some electric vehicles, an in-wheel motor structure in which an electric motor is built in each wheel has been put into practical use from the viewpoint of space efficiency and driving force transmission efficiency. Such an in-wheel motor structure is more susceptible to the outside air temperature than a configuration in which the electric motor is arranged in the vehicle body. Therefore, it is necessary to design a drive circuit for driving the electric motor in consideration of the back electromotive voltage in a lower temperature environment. For this reason, the drive circuit directed to the in-hole motor structure has to have a higher withstand voltage design, and there is a problem that the degree of design freedom is limited.

  The present invention has been made to solve such problems, and its object is to counteract the back electromotive force that occurs in an electric motor that drives a wheel using electromagnetic force of a permanent magnet regardless of the external temperature environment. It is an object of the present invention to provide a vehicle and a temperature raising method capable of suppressing voltage.

  A vehicle according to an aspect of the present invention is mechanically connected to a wheel, and an electric motor that drives the wheel using electromagnetic force generated by a permanent magnet, and a brake that is disposed in the vicinity of the electric motor and brakes rotation of the wheel by frictional force. And a magnet temperature acquisition means for acquiring the temperature of the permanent magnet, a determination means for determining the necessity of raising the temperature of the electric motor based on the acquired permanent magnet temperature, and a determination that the electric motor needs to be heated In this case, the motor is controlled so that a driving torque obtained by adding a predetermined incremental torque to a required torque determined according to the driving situation of the vehicle is generated, and the braking unit is set so that a braking torque corresponding to the incremental torque is generated. Control means for controlling.

  Preferably, the control means determines the incremental torque so that the drive torque matches the maximum torque that can be output in the electric motor.

Preferably, the electric motor and the braking part are incorporated in the wheel of the wheel.
Preferably, the electric motor includes a rotor in which a permanent magnet is embedded, and a stator that generates a current magnetic field for rotationally driving the rotor.

  According to another aspect of the present invention, there is provided a temperature raising method for raising the temperature of an electric motor mounted on a vehicle, wherein the vehicle is mechanically connected to a wheel and drives the wheel using electromagnetic force generated by a permanent magnet. An electric motor and a braking unit that is disposed in the vicinity of the electric motor and brakes the rotation of the wheel by friction force, and the temperature rising method is based on the step of acquiring the temperature of the permanent magnet, and the acquired permanent magnet temperature, A step of determining the necessity of temperature increase for the motor, and when it is determined that the temperature of the motor needs to be increased, a drive torque is generated by adding a predetermined incremental torque to the required torque that is determined according to the driving situation of the vehicle And a step of controlling the braking unit so that a braking torque corresponding to the incremental torque is generated when it is determined that it is necessary to raise the temperature of the motor.

  According to the present invention, it is possible to realize a vehicle and a temperature raising method that can suppress a back electromotive voltage generated in an electric motor that drives a wheel using electromagnetic force generated by a permanent magnet regardless of an external temperature environment.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

(overall structure)
FIG. 1 is a schematic configuration diagram of a vehicle 100 according to the embodiment of the present invention.

  Referring to FIG. 1, vehicle 100 according to the embodiment of the present invention typically includes an FR-based hybrid in which left and right rear wheels RL and RR are used as main drive wheels and left and right front wheels FL and FR are used as driven wheels. It is a four-wheel drive vehicle. The hybrid four-wheel drive vehicle adopts a two-wheel independent drive system in which the left and right rear wheels RL and RR are driven by the engine ENG and the motor generator MG2, and the left and right front wheels FL and FR are independently driven by the motor generators MGL and MGR. To do.

  The vehicle 100 includes motor generators MGL and MGR, speed reducers 6 and 8, braking units 56 and 58, rotation sensors 40 and 42, temperature sensors 62 and 64, as driving devices for the left and right front wheels FL and FR. A battery B, a boost converter 12, inverters 20L and 20R, and an electronic control unit (ECU: Electronic Control Unit; hereinafter, also simply referred to as “ECU”) 30 are provided.

  As the left and right front wheels FL, FR, an in-wheel motor structure in which a corresponding motor generator, reduction gear, and braking unit are incorporated in the wheel is employed. That is, the motor generator MGL, the speed reducer 6, the braking unit 56, the rotation sensor 40, and the temperature sensor 62 are provided in the corresponding front left wheel FL, and the motor generator MGR, the speed reducer 8, the braking unit 58, and the rotation sensor. 42 and the temperature sensor 64 are provided in the wheel of the corresponding right front wheel FR.

  Motor generators MGL and MGR are mechanically connected to drive shafts 2 and 4 of left and right front wheels FL and FR via speed reducers 6 and 8, respectively, and are driven independently using electromagnetic force generated by permanent magnets. . Typically, motor generators MGL and MGR are permanent magnet type three-phase AC synchronous rotating electric machines including a rotor in which a permanent magnet is embedded and a stator that generates a current magnetic field for rotationally driving the rotor.

  Motor generators MGL and MGR are driven by the electric power stored in battery B, and at the time of regenerative braking of vehicle 100, motor generators MGL and MGR operate as generators, respectively, and the regeneration generated by motor generators MGL and MGR Electric power is stored in battery B.

  Braking units 56 and 58 are arranged close to motor generators MGL and MGR, respectively, and brake the rotation of left and right front wheels FL and FR by frictional force. Typically, the braking units 56 and 58 are disc brakes, and by applying braking torque according to the control commands BRL and BRR from the ECU 30 to the brake disc formed integrally with the drive shafts 2 and 4, Generate braking force. As will be described later, part of the heat generated by the braking operation (frictional force) of the braking portions 56 and 58 is transmitted to the motor generators MGL and MGR.

  The rotation sensors 40 and 42 detect the rotational speeds ωFL and ωFR of the motor generators MGL and MGR, and the detection signals are input to the ECU 30. Temperature sensors 62 and 64 detect stator temperatures TsL and TsR of motor generators MGL and MGR, and the detection signals are input to ECU 30.

  As the battery B, a secondary battery such as nickel hydride or lithium ion, a fuel cell, or the like is applied. In addition, a large-capacity capacitor such as an electric double layer capacitor may be used as a power storage device instead of the battery B.

  Inverters 20L and 20R drive and control motor generators MGL and MGR in accordance with control commands PWMIL and PWMIR from ECU 30, respectively. Specifically, inverters 20L and 20R convert DC power supplied from battery B into predetermined AC power and supply it to motor generators MGL and MGR. At the time of regenerative braking of vehicle 100, motor generators MGL and MGR The AC power generated in step 1 is converted into DC power and returned to the battery B.

  Boost converter 12 is provided between inverters 20L, 20R and battery B, boosts the DC power supplied from battery B to a predetermined voltage and supplies it to inverters 20L, 20R. The DC power supplied from the inverters 20L and 20R is stepped down to a predetermined voltage and supplied to the battery B.

  Vehicle 100 further includes an engine ENG, motor generators MG1 and MG2, a power split mechanism PSD, a speed reducer RD, inverters 14 and 32, and rotation sensors 44 and 46 as driving devices for left and right rear wheels RL and RR. With.

  The engine ENG generates driving force using combustion energy of fuel such as gasoline as a source. The driving force generated by the engine ENG is divided into a path transmitted to the motor generator MG1 mainly functioning as a generator by the power split mechanism PSD and a path transmitted to the left and right rear wheels RL and RR via the speed reducer RD. Divided.

  Motor generator MG1 is rotated by the driving force from engine ENG transmitted through power split device PSD to generate electric power. The electric power generated by motor generator MG1 is supplied to inverter 14 and used as charging power for battery B or as driving power for motor generators MG2, MGL, and MGR.

  Motor generator MG2 is rotationally driven by AC power supplied from inverter 32. The driving force generated by the motor generator MG2 is transmitted to the driving shaft 45 of the left and right rear wheels RL and RR via the speed reducer RD. At the time of regenerative braking of vehicle 100, motor generator MG2 operates as a generator, and regenerative power generated by motor generator MG2 is stored in battery B.

  Rotation sensors 44 and 46 detect rotation speeds ω1 and ω2 of motor generators MG1 and MG2, respectively, and detection signals are input to ECU 30.

  Vehicle 100 further includes an accelerator position sensor 50 that detects accelerator pedal position AP, a brake pedal position sensor 52 that detects brake pedal position BP, and a shift position sensor 54 that detects shift position SP. The vehicle 100 further includes an outside air temperature sensor 48 that detects an outside air temperature Tout outside the vehicle 100. Detection signals from these sensors are input to the ECU 30.

  The ECU 30 is a control device mainly including a CPU (Central Processing Unit) that performs arithmetic processing and a memory unit such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The ECU 30 typically implements a predetermined control operation by the CPU executing a program stored in advance in a ROM or the like. Specifically, ECU 30 controls the operating state of engine ENG, the driving states of inverters 14, 32, 20 </ b> L, 20 </ b> R, the charging state of battery B, and the like according to the driving state of vehicle 100. Note that some or all of the functions realized by the ECU 30 may be realized by hardware.

  In particular, ECU 30 according to the present embodiment acquires the temperature of permanent magnets included in motor generators MGL and MGR having an in-wheel motor structure, and needs to increase the temperature of motor generators MGL and MGR based on the acquired permanent magnet temperatures. Judging. When it is determined that it is necessary to raise the temperature of the motor generators MGL and MGR, the braking units 56 and 58 actively perform a braking operation to generate heat, and the frictional heat causes the motor generators MGL and MGR to rise. Warm up. More specifically, ECU 30 controls motor generators MGL and MGR so that a drive torque obtained by adding a predetermined incremental torque to a required torque determined according to the driving state of vehicle 100 is generated, and the incremental torque is set to the incremental torque. The braking units 56 and 58 are controlled so that the corresponding braking torque is generated.

  Here, ECU 30 may continuously determine the necessity of temperature increase for motor generators MGL and MGR during a period in which vehicle 100 is in an activated state (ignition on (IGON) state). Since the motor generators MGL and MGR are sufficiently heated by heat generated from the motor generators MGL and MGR, the necessity of raising the temperature is determined at the initial stage of starting the vehicle 100, that is, when an IGON (ignition on) signal is given by the driver. Just do it.

  Although the temperature raising operations for motor generators MGL and MGR can be performed independently of each other, in many cases, it is considered that the temperatures of motor generators MGL and MGR are substantially equal to each other. A temperature raising operation is performed in parallel with the generator.

  With respect to the correspondence relationship between the embodiment of the present invention shown in FIG. 1 and the present invention, motor generators MGL and MGR correspond to “electric motors”, and braking portions 56 and 58 correspond to “braking portions”.

(Configuration of drive circuit)
FIG. 2 is a schematic block diagram of a drive circuit for driving a motor generator in vehicle 100 in FIG.

  Referring to FIG. 2, the drive circuit includes battery B, boost converter 12, inverters 14, 32, 20 R, 20 L, voltage sensors 10, 13, current sensors 22, 24, 26, 28, and ECU 30. including.

  Boost converter 12 is provided between battery B and inverters 14, 32, 20 R, 20 L, and can boost DC power supplied from battery B to a predetermined voltage, and inverters 14, 32, 20 R, It is possible to step down the DC power returned from any of 20L to the charging voltage of battery B. In other words, boost converter 12 is a step-up / step-down chopper circuit, and includes a reactor L1, switching elements Q1, Q2, and diodes D1, D2. Reactor L1 has one end connected to the power line of battery B and the other end connected to an intermediate point between switching element Q1 and switching element Q2. Switching elements Q1, Q2 are connected in series between the power supply line and the earth line. Between the collectors and emitters of the switching elements Q1 and Q2, diodes D1 and D2 that flow current from the emitter side to the collector side are connected. Switching elements Q1, Q2 are typically made of an IGBT (Insulated Gate Bipolar Transistor), a power MOS transistor, or the like.

  Voltage sensor 10 detects the voltage across battery B, that is, input voltage Vb of boost converter 12, and outputs the detected input voltage Vb to ECU 30.

  Inverter 14 includes U-phase arm 15, V-phase arm 16, and W-phase arm 17. U-phase arm 15, V-phase arm 16 and W-phase arm 17 are provided in parallel between the power supply line and the earth line.

  U-phase arm 15 includes switching elements Q3 and Q4 connected in series, V-phase arm 16 includes switching elements Q5 and Q6 connected in series, and W-phase arm 17 includes switching elements Q7 and Q7 connected in series. Consists of Q8. An intermediate point of each phase arm is connected to each phase end of each phase coil of motor generator MG1. Further, diodes D3 to D8 that flow current from the emitter side to the collector side are connected between the collectors and emitters of the switching elements Q3 to Q8, respectively.

  Switching elements Q3 to Q8 are also typically composed of IGBTs or power MOS transistors.

  Since inverters 32, 20R and 20L have the same configuration as inverter 14, detailed description thereof will not be repeated.

  Capacitor C2 smoothes the DC voltage from boost converter 12, and supplies the smoothed DC voltage to inverters 14, 32, 20R, and 20L. The voltage sensor 13 detects the voltage across the capacitor C2, that is, the output voltage Vm of the boost converter 12 (corresponding to the input voltage to the inverters 14, 32, 20R, and 20L. The same applies hereinafter), and the detected output voltage. Vm is output to the ECU 30.

  Current sensor 22 detects motor current MCRT1 flowing through motor generator MG1, and outputs the detected motor current MCRT1 to ECU 30. Similarly, current sensor 24 detects motor current MCRT2 flowing through motor generator MG2, and outputs the detected motor current MCRT2 to ECU 30. Similarly, current sensor 26 detects motor current MCRTR flowing through motor generator MGR and outputs the detected motor current MCRTR to ECU 30. Similarly, current sensor 28 detects motor current MCRTL flowing through motor generator MGL, and outputs the detected motor current MCRTL to ECU 30.

(In-wheel motor structure)
FIG. 3 is a cross-sectional view of left and right front wheels FL, FR in which motor generators MGL, MGR shown in FIG. 1 are incorporated as in-wheel motors. Since both the left and right front wheels FL and FR have the same configuration, FIG. 3 representatively shows a cross-sectional configuration of the left front wheel FL.

  Referring to FIG. 3, left front wheel FL includes a motor generator MGL, a rotation sensor 40, a speed reducer 6, a drive shaft 2, a wheel hub 220, and a wheel disc 230. Motor generator MGL, reduction gear 6 and rotation sensor 40 are housed in a case.

  The motor generator MGL includes a stator having a stator core 420 and a stator coil 430, a rotating shaft 450 that is rotatably supported by a bearing portion 440 in the stator, and a rotor formed integrally with the rotating shaft 450. 410. Further, a plurality of permanent magnets (not shown) are embedded in the surface or inside of the rotor 410.

  A rotation sensor 40 for detecting the rotation speed of the rotor 410 is connected to the rotation shaft 450 via a joint portion 460.

  Reducer 6 includes a first gear 610 coupled to rotor 410 of motor generator MGL, a second gear 620 that meshes with first gear 610, and a third gear 630 that meshes with second gear 620. ing. A wheel disc 230 is connected to the third gear 630 via the drive shaft 2 and the wheel hub 220. Further, a tire (not shown) is mounted on the outer peripheral side of the wheel disc 230.

  The brake unit 56 includes a brake disc 500 that rotates integrally with the drive shaft 2 and the wheel hub 220, a brake caliper 510 that applies a braking force in the circumferential direction by pressing forces from both side surfaces of the brake disc 500, and a brake caliper. And a hydraulic pressure generator 520 that drives 510.

  The brake disc 500 is fastened to the drive shaft 2 and the wheel hub 220 and generates a frictional force in the circumferential direction between the brake disc 500 and the brake pad 530 driven in the axial direction by the brake caliper 510. This frictional force generates frictional heat from the brake disc 500. The frictional heat is generated when a part of the kinetic energy of the vehicle 100 is changed to heat energy, and the rotation of the left and right front wheels FL and FR is braked by this energy conversion.

  The hydraulic pressure generator 520 generates a predetermined hydraulic pressure so that a braking torque according to a control command BRL given from the ECU 20 (FIG. 1) is given to the brake disc 500. The ECU 20 outputs the control commands BRL and BRR in response to the operation of the brake pedal by the driver during normal traveling, but it is necessary to raise the temperature of the motor generators MGL and MGR as described in detail below. The control command BRL is output so that predetermined frictional heat is generated.

  In particular, in the in-wheel motor structure according to the present embodiment, frictional heat generated in brake disc 500 is generated in the order of drive shaft 2 (or 4), third gear 630, second gear 620, first gear 610, and rotor 410. Heat transfer (heat flow) is performed to raise the temperature of the motor generator MGL (or MGR).

(Motor generator temperature rise processing)
FIG. 4 is a characteristic diagram showing the relationship between the counter electromotive voltage generated by the rotation of motor generators MGL and MGR and the withstand voltage of the switching elements constituting the corresponding inverter. The counter electromotive voltage shown in FIG. 4 is a voltage value (phase voltage value) with respect to a neutral point when the motor generator rotates at the maximum allowable rotation speed. That is, FIG. 4 shows the maximum value of the back electromotive voltage that can be generated by the motor generator.

FIG. 4A shows the relationship in a conventional vehicle.
FIG. 4B shows a relationship in vehicle 100 according to the present embodiment.

  Referring to FIG. 4 (a), it is generated by rotation of the motor generator in an assumed temperature range of the motor generator, that is, in a range from a lower limit temperature (for example, −50 ° C.) to an upper limit temperature (for example, 130 ° C.). The back electromotive force increases as the temperature decreases. On the other hand, the withstand voltage characteristic of the switching elements constituting the inverter decreases as the temperature decreases.

  Therefore, the conventional vehicle is designed such that the withstand voltage of the switching element is equal to or higher than the maximum counter electromotive voltage Va that can be generated by the rotation of the motor generator at the lower limit temperature. More realistically, the withstand voltage is designed to have a predetermined margin.

  As a result of such a design, for example, the withstand voltage of the switching element at the use upper limit temperature is significantly higher than the counter electromotive voltage generated by the rotation of the motor generator MG, and there is an excessive margin. Such an excessive margin is a waste in design, and there is a problem of restricting the degree of freedom in design.

  On the other hand, referring to FIG. 4B, in the present embodiment, for example, when an IGON signal that is a command for starting vehicle 100 is given by the driver, the temperature of the permanent magnet embedded in the rotor Is lower than a predetermined threshold temperature (corresponding to the permanent magnet use lower limit temperature), the temperature increase operation of the motor generator is started immediately after the vehicle 100 starts to travel. Such a temperature raising operation is continued at least until the temperature of the permanent magnet reaches the permanent magnet use lower limit temperature.

  By such a temperature raising operation, the temperature of the permanent magnet of the motor generator can be quickly removed from the temperature raising region (region where the temperature is lower than the permanent magnet use lower limit temperature) shown in FIG. There is no problem even if there is a region where the withstand voltage exceeds the counter electromotive force generated by the rotation of the motor generators MGL and MGR.

  During the temperature raising operation of motor generators MGL and MGR, the traveling speed of vehicle 100 may be limited in consideration of the magnitude of the counter electromotive voltage generated by the rotation.

  Thus, in vehicle 100 according to the present embodiment, if the withstand voltage of the switching element is designed in consideration of only the back electromotive voltage that can be generated by rotation of motor generator MG in a region where the temperature is higher than the permanent magnet use lower limit temperature. Good. As a result, the withstand voltage required for the switching element can be reduced as compared with the conventional vehicle, and a permanent magnet having a larger magnetic force (magnetic flux density), that is, capable of generating a larger driving torque can be employed. . In this way, the degree of design freedom can be further increased, and more economical design is possible.

(Control structure)
Next, with reference to FIGS. 5 to 7, a control structure for realizing the temperature raising process according to the present embodiment will be described. In the following, when the motor generators MGL and MGR are not distinguished from each other, the suffix may be omitted such as “stator temperature Ts” or “permanent magnet temperature Tp”.

  FIG. 5 is a functional block diagram showing an outline of functions for generating a temperature increase request in the temperature increase processing according to the present embodiment. In addition, ECU30 implement | achieves the function shown in FIGS. 5-7 by CPU included in it reading the program previously memorize | stored in ROM etc. on RAM, and running the said program.

  Referring to FIG. 5, ECU 30 includes magnet temperature acquisition units 342 and 352, comparison units 344 and 354, temperature increase request generation units 346 and 356, and generated heat amount integration units 348 and 358 as its functions.

  When receiving the IGON signal, the magnet temperature acquisition units 342 and 352 are embedded in the rotor of the corresponding motor generator based on the stator temperatures TsL and TsR of the corresponding motor generator, the outside air temperature Tout, and the values stored therein. The permanent magnet temperatures TpL and TpR of the permanent magnets are acquired. Magnet temperature acquisition units 342 and 352 output acquired permanent magnet temperatures TpL and TpR to comparison units 344 and 354, respectively. In addition, the process for acquiring permanent magnet temperature TpL, TpR in the magnet temperature acquisition part 342,352 is mentioned later.

  Comparison units 344 and 354 compare permanent magnet temperatures TpL and TpR output from magnet temperature acquisition units 342 and 352, respectively, with a predetermined threshold temperature Tth. Comparison units 344 and 354 then output the temperature differences ΔTpL and ΔTpR to temperature increase request generation units 346 and 356, respectively.

  The temperature increase request generation units 346 and 356, if the permanent magnet temperatures TpL and TpR are lower than the threshold temperature Tth, that is, if the temperature differences ΔTpL and ΔTpR are negative values, the temperature increase request L and the temperature increase request R, respectively. To emit. Further, the temperature increase request generation units 346, 356 determine the amount of heat (J: Joule) to be generated by the braking units 56, 58 based on the temperature differences ΔTpL, ΔTpR. Specifically, the temperature increase request generators 346 and 356 calculate the amount of heat necessary for realizing the temperature increase of the temperature difference ΔT in consideration of the heat capacity and heat transfer efficiency of the entire rotor.

The generated heat amount integrating units 348 and 358 will be described later.
FIG. 6 is a functional block diagram showing an outline of functions for performing the temperature raising operation in the temperature raising processing according to the present embodiment.

  Referring to FIG. 6, ECU 30 includes a driver request calculation unit 362, a battery state calculation unit 366, a total output calculation unit 364, a driving force distribution unit 368, a maximum torque calculation units 372 and 382, and an addition unit. 374, 384 are included as functions.

  Referring to FIG. 6, driver request calculation unit 362 is typically detected by accelerator pedal position AP detected by accelerator position sensor 50 (FIG. 1) and by brake pedal position sensor 52 (FIG. 1). A driver request is calculated based on the brake pedal position BP and the shift position SP detected by the shift position sensor 54 (FIG. 1). That is, the driver request calculation unit 362 calculates the driving situation of the vehicle 100 based on the signals from each sensor and outputs the calculation result to the total output calculation unit 364. The driver request calculation unit 362 may be input with a signal corresponding to the amount of operation of the steering wheel by the driver or the road surface condition.

  Battery state calculation unit 366 typically calculates a state of charge (SOC) of battery B based on input voltage Vb of boost converter 12 detected by voltage sensor 10 (FIG. 2). The calculation result is output to the total output calculation unit 364. In order to increase the calculation accuracy of the charge state value of battery B, it is preferable to use the input / output current value and temperature of battery B.

  The total output calculation unit 364 is requested to drive the vehicle 100 based on the driver request calculated by the driver request calculation unit 362 and the charge state value of the battery B calculated by the battery state calculation unit 366. The total output (power) is calculated. In the present specification, “output” or “power” means the product of the torque and the rotational speed (watt: W = J / s). Furthermore, the total output calculation unit 364 determines the driving force distribution between the engine ENG and the motor generators MG2, MGR, MGL for the total output. Specifically, total output calculation unit 364 determines engine ENG operating points (engine output target value and engine speed target value) in consideration of fuel consumption efficiency, and then motor generators MG1, MG2, MGR, The driving force to be shared by the MGL is determined.

Further, the driving force distribution unit 368 further distributes the driving force determined by the total output calculation unit 364 to each of the motor generators MG1, MG2, MGR, MGL, and based on the rotational speeds ω1, ω2, ωFL, ωFR, Required torques Tm1 ^* , Tm2 ^* , TmL ^* , and TmR ^* for each of motor generators MG1, MG2, MGR, and MGL are calculated. Since motor generator MG1 mainly functions as a generator, required torque Tm1 ^* is a negative value.

Driving force distribution unit 368 controls inverters 14 and 32 (FIG. 1) so that motor generators MG1 and MG2 generate required torques Tm1 ^* and Tm2 ^* , respectively.

On the other hand, the required torque TmL ^* output from the driving force distribution unit 368 is given to the maximum torque calculation unit 372 and the addition unit 374. Similarly, the required torque TmR ^* output from the driving force distribution unit 368 is given to the maximum torque calculation unit 382 and the addition unit 384.

Here, the maximum torque calculation units 372 and 382 respond to the temperature increase request L and the temperature increase request R from the temperature increase request generation units 346 and 356 (FIG. 5), respectively, and request torques TmL ^* and TmR ^* , respectively. predetermined increment torque added drive torque #TmL ^*, as well as calculating the # TmR ^*, it controls the braking portion 56, 58 so braking torque corresponding to the incremental torque is generated.

More specifically, in response to temperature increase request L, maximum torque calculation unit 372 calculates the maximum torque that can be output by motor generator MGL. As an example, the maximum torque calculator 372 is based on the stator temperature TsL of the motor generator MGL detected by the temperature sensor 62 (FIGS. 1 and 3) and the rotational speed ωFL of the motor generator MGL detected by the rotation sensor 44. The maximum torque that can be output is calculated by referring to a predetermined map or the like. Then, the maximum torque calculation unit 372, and outputs the calculated output can request from the maximum torque torque TmL ^* a reduced value, i.e., the margin torque to the request torque TmL ^* printable maximum torque as an incremental torque ΔTmL ^*.

Adder 374 outputs a value obtained by adding this incremental torque ΔTmL ^* to required torque TmL ^* from driving force distribution unit 368 as drive torque # TmL ^* for motor generator MGL. That is, drive torque # TmL ^* matches the maximum torque that can be output from motor generator MGL calculated by maximum torque calculation unit 372.

On the other hand, maximum torque calculation unit 372 outputs incremental torque ΔTmL ^* as a control command BRL (braking torque command) for braking unit 56. Braking unit 56 generates a braking torque in accordance with this control command BRL, and motor generator MGL is heated by the frictional heat generated by this braking torque.

Here, motor generator MGL generates a driving torque corresponding to driving torque # TmL ^* , and corresponding braking unit 56 generates a braking torque corresponding to incremental torque ΔTmL ^* . As a result, the drive torque generated as a whole of the left front wheel FL is (drive torque # TmL ^* −increment torque ΔTmL ^* ) = (required torque TmL ^* ), so that the travel of the vehicle 100 is not affected.

  The same applies to the right front wheel FR that is torque-controlled by the maximum torque calculation unit 382 and the addition unit 384, and thus detailed description will not be repeated.

Referring again to FIG. 5, generated heat amount integration units 348 and 358 integrate the heat amounts generated by braking units 56 and 58 after the temperature raising operation is started, and output them to temperature increase request generation units 346 and 356, respectively. To do. The temperature increase request generation units 346 and 356 issue the temperature increase request as described above,
The amount of heat necessary to realize the temperature increase of the temperature difference ΔT is calculated. Therefore, the temperature increase request generation units 346 and 356 determine the timing to end the temperature increase operation, that is, the timing to stop the output of the temperature increase request, based on the heat amounts integrated by the generated heat amount integration units 348 and 358.

More specifically, generated heat amount integration unit 348 generates a unit time generated in braking unit 56 from the product of incremental torque ΔTmL ^* (FIG. 6) calculated by maximum torque calculation unit 372 and rotation speed ωFL of motor generator MGL. The calorific value (watt: W) per unit is calculated, and the calculated calorific value per unit time is integrated over time. Similarly for generated heat amount integrating unit 358, the product per unit time generated in braking unit 58 is calculated from the product of incremental torque ΔTmR ^* (FIG. 6) calculated by maximum torque calculating unit 382 and rotation speed ωFR of motor generator MGR. The calorific value is calculated, and the calculated calorific value per unit time is integrated over time.

  As described above, the temperature raising operation of motor generators MGL and MGR can be controlled by the control structure shown in FIGS.

(Magnet temperature acquisition part)
If the sensor is directly attached to the rotor of the rotating body to detect the temperature of the permanent magnet, the configuration of the motor generator becomes complicated. Therefore, in the embodiment of the present invention, the permanent magnet temperature Tp embedded in the rotor is estimated based on the stator temperature Ts, the outside air temperature Tout, and the value stored therein.

  The amount of heat (heat loss) generated in the rotor by supplying a normal drive current is different from the amount of heat generated in the stator. Further, the heat diffusion characteristics of the stator and the rotor are also different from each other. Therefore, a temperature difference may occur between stator temperature Ts and permanent magnet temperature Tp during operation of motor generators MGR and MGL.

  On the other hand, after the motor generator MG stops operating, that is, after receiving an IGOFF (ignition off) signal, no heat loss occurs in the stator and the rotor. Therefore, the stator temperature Ts and the permanent magnet temperature Tp gradually approach the environmental temperature according to the respective thermal diffusion time constants.

  Therefore, if a sufficient time has elapsed after receiving the IGOFF signal, it can be considered that both the stator temperature Ts and the permanent magnet temperature Tp are uniformly at the ambient environmental temperature. Therefore, the permanent magnet temperature Tp can be regarded as the same as the stator temperature Ts. Therefore, the ECU 30 measures the elapsed time since receiving the previous IGOFF signal, and if the measured elapsed time exceeds a predetermined threshold time when the next IGON signal is received. The stator temperature Ts is considered to be the same as the permanent magnet temperature Tp. Note that the predetermined threshold time is appropriately set according to the thermal diffusion time constants of the stator and the rotor.

  On the other hand, if sufficient time has not elapsed since the last IGOFF signal was received, that is, if the measured elapsed time is less than or equal to a predetermined threshold time, the permanent magnet temperature Tp is still in the surrounding environment. It can be considered that the temperature has not been reached. Here, the thermal diffusion of the stator and the rotor does not occur independently of each other, but exerts a thermal effect on each other. Therefore, a relatively large interrelationship exists between the stator thermal diffusion process and the rotor thermal diffusion process. Therefore, the ECU 30 calculates a first estimated value for the permanent magnet temperature Tp according to the thermal diffusion process of the stator.

  It is also preferable to consider the influence of the environmental temperature. Therefore, the ECU 30 calculates the second estimated value for the permanent magnet temperature Tp based on the temperature difference between the outside air temperature Tout at the time of receiving the previous IGOFF signal and the outside air temperature Tout at the time of receiving the current IGON signal. Calculate.

  The first estimated value and the second estimated value calculated as described above are added to obtain the permanent magnet temperature.

  Specifically, the first estimated value using the stator temperature at the time of receiving the IGOFF signal (hereinafter also referred to as the final stator temperature) as the first parameter and the elapsed time after receiving the IGOFF signal as the second parameter. This map is experimentally acquired in advance. In addition, a map for the second estimated value is preliminarily set using the temperature difference between the outside air temperature at the time of receiving the IGOFF signal (hereinafter also referred to as the final outside air temperature) and the outside air temperature Tout at the time of receiving the IGON signal as a parameter. Obtained experimentally.

  Then, the ECU 30 acquires the temperature of the permanent magnet from the first and second estimated values obtained by referring to the respective maps based on the detected parameter values.

  FIG. 7 is a functional block diagram showing an outline of functions of the magnet temperature acquisition units 342 and 352 shown in FIG.

  Referring to FIG. 7, each of magnet temperature acquisition units 342 and 352 includes stop time measurement unit 302, comparison unit 304, register units 306 and 312, first estimation unit 308, addition unit 310, and subtraction. The part 314, the 2nd estimation part 316, and the selection part 318 are included as a function.

  When the stop time measuring unit 302 receives the IGOFF signal, the stop time measuring unit 302 starts measuring the elapsed time TIM from the time point. Then, the stop time measurement unit 302 outputs the elapsed time TIM to be measured to the comparison unit 304 and the first estimation unit 308. In addition, every time the stop time measurement unit 302 receives the IGOFF signal, the stop time TIM during measurement is temporarily reset and measurement is started again. Therefore, the elapsed time TIM output from the stop time measuring unit 302 corresponds to the elapsed time from the time when the latest IGOFF signal is received.

  The comparison unit 304 compares the elapsed time TIM given from the stop time measurement unit 302 with a predetermined threshold time TIMth. Then, the comparison unit 304 outputs the comparison result to the selection unit 318.

  Upon receiving the IGOFF signal, the register unit 306 acquires the stator temperature Ts at that time and stores it as the final stator temperature Ts (last). Then, the register unit 306 outputs and holds the stored final stator temperature Ts (last) to the first estimation unit 308 until the next IGOFF signal is received. The register unit 306 resets the stored final stator temperature Ts (last) every time it receives the IGOFF signal. Therefore, the final stator temperature Ts (last) output from the register unit 306 corresponds to the stator temperature Ts at the time of receiving the latest IGOFF signal.

  The first estimation unit 308 stores a map that defines the first estimated value #Tpa using the final stator temperature Ts (last) and the elapsed time TIM as parameters. Then, the first estimating unit 308 refers to the map to be stored based on the final stator temperature Ts (last) given from the register unit 306 and the elapsed time TIM given from the stop time measuring unit 302, and performs a corresponding first operation. 1 Estimate value #Tpa is determined. Then, the first estimation unit 308 outputs the determined first estimation value #Tpa to the addition unit 310.

  Upon receipt of the IGOFF signal, the register unit 312 acquires the outside air temperature Tout at the time point and stores it as the final outside air temperature Tout (last). Then, the register unit 312 outputs and holds the stored final outside air temperature Tout (last) to the subtraction unit 314 until the next IGOFF signal is received. Each time the register unit 312 receives the IGOFF signal, it resets the stored final outside air temperature Tout (last). Therefore, the final outside air temperature Tout (last) output from the register unit 312 corresponds to the outside air temperature Tout at the time of receiving the latest IGOFF signal.

  The subtracting unit 314 calculates a temperature difference ΔTout between the final outside air temperature Tout (last) given from the register unit 312 and the current outside air temperature Tout, and outputs it to the second estimating unit 316.

  The second estimation unit 316 stores a map that defines the first estimated value #Tpa using the temperature difference ΔTout as a parameter. Then, the second estimating unit 316 determines the corresponding second estimated value #Tpb with reference to the stored map based on the temperature difference ΔTout given from the subtracting unit 314. Then, the second estimation unit 316 outputs the determined second estimation value #Tpb to the addition unit 310.

  Adder 310 adds first estimated value #Tpa given from first estimating unit 308 and second estimated value #Tpb given from second estimating unit 316, and outputs the result to selecting unit 318.

  The selection unit 318 outputs either the current stator temperature Ts or the addition value given from the addition unit 310 as the permanent magnet temperature Tp according to the comparison result given from the comparison unit 304. That is, if the elapsed time TIM exceeds the threshold time TIMth, the current stator temperature Ts is output as the permanent magnet temperature Tp. On the other hand, if the elapsed time TIM is equal to or less than the threshold time TIMth, the addition value of the first estimated value #Tpa and the second estimated value #Tpb given from the adding unit 310 is output as the permanent magnet temperature Tp.

  In the description of FIG. 7 described above, the motor generators MGL and MGR have been described generically, but actually, a control structure shown in FIG. 7 is provided corresponding to each of the motor generators MGL and MGR.

  As for the correspondence between the embodiment of the present invention shown in FIG. 1 and the present invention, the comparison units 344 and 354 correspond to “determination means”, and the maximum torque calculation units 372 and 382 and the addition units 374 and 384 “control”. Corresponds to “means”.

(Processing flow)
FIG. 8 is a flowchart showing a processing procedure related to the temperature raising operation according to the present embodiment. The processing procedure shown in FIG. 8 is executed when an IGON signal is given.

  5, 6 and 8, ECU 30 functioning as magnet temperature acquisition unit 342 calls a magnet temperature acquisition subroutine for motor generator MGL to acquire permanent magnet temperature TpL for motor generator MGL. (Step S102). Then, ECU 30 functioning as comparison unit 344 determines whether or not acquired permanent magnet temperature TpL is lower than a predetermined threshold temperature Tth (step S104).

  When permanent magnet temperature TpL is not lower than a predetermined threshold temperature Tth (NO in step S104), subsequent processing relating to the temperature raising operation for motor generator MGL is not performed.

  When permanent magnet temperature TpL is lower than a predetermined threshold temperature Tth (YES in step S104), ECU 30 functioning as temperature increase request generation unit 346 performs temperature increase request L for motor generator MGL. Is issued (step S106). At the same time, ECU 30 functioning as temperature increase request generation unit 346 calculates the amount of heat necessary for increasing the temperature of motor generator MGL to a threshold temperature Tth or higher (step S108).

ECU 30 functioning as maximum torque calculation unit 372 calculates the maximum torque that can be output from motor generator MGL (step S110). Further, ECU 30 functioning as maximum torque calculation unit 372 calculates incremental torque ΔTmL ^* from the maximum torque that motor generator MGL can output and required torque TmL ^* determined according to the driving condition of vehicle 100 (step). S112).

ECU 30 functioning as addition unit 374 torque-controls motor generator MGL so that drive torque # TmL ^* is generated by adding incremental torque ΔTmL ^* to required torque TmL ^* (step S114). At the same time, the ECU 30 that functions as the maximum torque calculation unit 372 controls the torque of the braking unit 56 so that a braking torque corresponding to the incremental torque ΔTmL ^* is generated (step S116).

Subsequently, ECU 30 functioning as generated heat amount integrating unit 348 integrates the amount of heat generated by braking unit 56 based on incremental torque ΔTmL ^* and rotation speed ωFL of motor generator MGL (step S118). Then, ECU 30 functioning as temperature increase request generation unit 346 determines whether or not the amount of heat generated in step S118 has reached the amount of heat necessary for temperature increase calculated in step S108 (step S120).

  If the amount of heat necessary for the temperature increase has not been reached (NO in step S120), the processes after step S110 are executed again.

  On the other hand, when the amount of heat necessary for temperature increase has been reached (YES in step S120), ECU 30 functioning as temperature increase request generation unit 346 stops outputting temperature increase request L ( Step S122).

  In parallel with the processing of steps S102 to 122 described above, the following processing of steps S132 to 152 is executed.

  ECU 30 functioning as magnet temperature acquisition unit 352 calls a magnet temperature acquisition subroutine for motor generator MGR to acquire permanent magnet temperature TpR for motor generator MGR (step S132). Then, ECU 30 functioning as comparison unit 354 determines whether or not acquired permanent magnet temperature TpR is lower than a predetermined threshold temperature Tth (step S134).

  When permanent magnet temperature TpR is not lower than a predetermined threshold temperature Tth (NO in step S134), the subsequent processing relating to the temperature raising operation for motor generator MGR is not performed.

  When permanent magnet temperature TpR is lower than a predetermined threshold temperature Tth (YES in step S134), ECU 30 functioning as temperature increase request generation unit 356 has a temperature increase request R for motor generator MGR. Is issued (step S136). At the same time, ECU 30 functioning as temperature increase request generation unit 356 calculates the amount of heat necessary for increasing the temperature of motor generator MGR to a threshold temperature Tth or higher (step S138).

ECU 30 functioning as maximum torque calculation unit 382 calculates the maximum torque that can be output from motor generator MGR (step S140). Further, ECU 30 functioning as maximum torque calculation unit 382 calculates incremental torque ΔTmR ^* from the maximum torque that motor generator MGR can output and required torque TmR ^* determined according to the driving condition of vehicle 100 (step). S142).

ECU30 functioning as a summing unit 384, the required torque TmR ^* incremental torque DerutaTmR ^* a as driving torque #TmR ^* is generated in addition to the torque control of the motor generator MGR (step S144). At the same time, the ECU 30 functioning as the maximum torque calculating unit 382 controls the torque of the braking unit 58 so that a braking torque corresponding to the incremental torque ΔTmR ^* is generated (step S146).

Subsequently, ECU 30 functioning as generated heat amount integrating unit 358 integrates the amount of heat generated by braking unit 58 based on incremental torque ΔTmR ^* and rotation speed ωFR of motor generator MGR (step S148). Then, ECU 30 functioning as temperature increase request generation unit 356 determines whether or not the amount of heat generated in step S148 has reached the amount of heat necessary for temperature increase calculated in step S138 (step S150).

  If the amount of heat necessary for the temperature increase has not been reached (NO in step S150), the processing after step S140 is executed again.

  On the other hand, when the amount of heat necessary for temperature increase has been reached (YES in step S150), ECU 30 functioning as temperature increase request generation unit 356 stops the output of temperature increase request R ( Step S152).

And after execution of step S122 and S152, temperature rising operation is complete | finished.
As described above, in vehicle 100 according to the present embodiment, permanent magnet temperature Tp may be acquired based on previously stored final stator temperature Ts (last) and final outside air temperature Tout (last). . Therefore, when the IGOFF signal is given, the vehicle 100 performs the following stop process.

  FIG. 9 is a flowchart showing a processing procedure related to the stop processing according to the present embodiment. The processing procedure shown in FIG. 9 is executed when an IGOFF signal is given.

  Referring to FIGS. 7 and 9, ECU 30 functioning as register unit 306 stores stator temperature TsL of motor generator MGL at that time as final stator temperature TsL (last) (step S202), and motor at that time Stator temperature TsR of generator MGR is stored as final stator temperature TsR (last) (step S204). Then, the ECU 30 functioning as the register unit 312 stores the outside air temperature Tout at the time as the final outside air temperature Tout (last) (step S206).

  Furthermore, the ECU 30 functioning as the stop time measuring unit 302 starts measuring the elapsed time TIM after receiving the IGOFF signal (step S208). The measurement of the elapsed time TIM is continued until a new IGOFF signal is given.

  FIG. 10 is a flowchart showing a processing procedure according to the magnet temperature acquisition subroutine in steps S102 and S132 of FIG. The processing procedure shown in FIG. 10 is executed in response to a call from the main routine.

  Referring to FIGS. 7 and 10, ECU 30 functioning as comparison unit 304 acquires elapsed time TIM being measured (step S300), and whether the acquired elapsed time TIM exceeds threshold time TIMth or not. Is determined (step S302).

  When elapsed time TIM exceeds threshold time TIMth (YES in step S302), ECU 30 functioning as selection unit 318 obtains the current stator temperature Ts of the corresponding motor generator (step S304). The obtained stator temperature Ts is output as the corresponding permanent magnet temperature Tp of the motor generator (step S306). Then, the process returns to the main routine.

  On the other hand, when elapsed time TIM does not exceed threshold time TIMth (NO in step S302), ECU 30 functioning as first estimating unit 308 determines the final stored motor generator. The stator temperature Ts (last) is read (step S308), and the first estimation is made with reference to the stored map based on the read final stator temperature Ts (last) and the elapsed time TIM of the corresponding motor generator. The value #Tma is determined (step S310).

  Further, the ECU 30 functioning as the subtracting unit 314 reads the stored final outside air temperature Tout (last) (step S312) and acquires the current outside air temperature Tout (step S314). Further, the ECU 30 functioning as the subtracting unit 314 calculates a temperature difference ΔTout between the read final outside air temperature Tout (last) and the outside air temperature Tout (step S316).

  The ECU 30 functioning as the second estimation unit 316 determines the second estimated value #Tmb with reference to the map to be stored based on the temperature difference ΔTout calculated in step S316 (step S318).

  The ECU 30 functioning as the adding unit 310 uses the added value of the first estimated value #Tpa determined in step S310 and the second estimated value #Tpb determined in step S318 as the permanent magnet temperature Tp of the corresponding motor generator. (Step S320). Then, the process returns to the main routine.

  In the present embodiment, a vehicle having two in-wheel motor structure drive wheels has been described. However, the number of drive wheels is not limited, and one or three or more in-wheel motor structures are provided. A vehicle provided with driving wheels may be used.

  Further, in the embodiment of the present invention, the FR-based hybrid four-wheel drive vehicle has been described as an example, but any vehicle having at least one drive wheel having an in-wheel motor structure may be used. Applicable.

  Further, in the present embodiment, as a more preferable form, in order to acquire the temperature of the permanent magnet embedded in the rotor, the stator temperature and the external temperature are not used without using a temperature sensor for directly detecting the permanent magnet temperature. Although the structure which estimates temperature based on temperature etc. was demonstrated, it is not restricted to this structure. That is, a temperature detector such as a radiation thermometer that can detect the surface temperature in a non-contact manner may be used, and any known temperature detection method may be employed.

  According to the embodiment of the present invention, when the temperature of the permanent magnet embedded in the rotor of the motor generator is lower than the use lower limit temperature, the motor generator is heated by positive heat generation from the braking unit. Thereby, it is possible to avoid the influence of the counter electromotive voltage that may occur when the temperature of the motor generator is low. Therefore, as compared with a conventional vehicle, a withstand voltage required for the switching element can be relaxed, and a permanent magnet having a larger magnetic force (magnetic flux density), that is, capable of generating a larger driving torque can be employed. In this way, the degree of design freedom can be further increased, and more economical design is possible.

  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.

1 is a schematic configuration diagram of a vehicle 100 according to an embodiment of the present invention. FIG. 2 is a schematic block diagram of a drive circuit that drives a motor generator in the vehicle 100 of FIG. 1. FIG. 2 is a cross-sectional view of left and right front wheels FL, FR in which motor generators MGL, MGR shown in FIG. 1 are incorporated as in-wheel motors. FIG. 6 is a characteristic diagram showing a relationship between a counter electromotive voltage generated by rotation of motor generators MGL and MGR and a withstand voltage of a switching element constituting a corresponding inverter. It is a functional block diagram which shows the outline of the function for generating a temperature rising request | requirement in the temperature rising process according to this Embodiment. It is a functional block diagram which shows the outline of the function for performing temperature rising operation in the temperature rising process according to this Embodiment. It is a functional block diagram which shows the outline of the function of the magnet temperature acquisition part 342,352 shown in FIG. It is a flowchart which shows the process sequence which concerns on the temperature rising operation according to this Embodiment. It is a flowchart which shows the process sequence which concerns on the stop process according to this Embodiment. It is a flowchart which shows the process sequence which concerns on the magnet temperature acquisition subroutine in FIG.8 S102 and S132.

Explanation of symbols

  2, 4, 45 Drive shaft, 6, 8, RD Reducer, 10, 13 Voltage sensor, 12 Boost converter, 14, 32, 20L, 20R Inverter, 15 U-phase arm, 16 V-phase arm, 17 W-phase arm, 22, 24, 26, 28 Current sensor, 40, 42, 44, 46 Rotation sensor, 48 Outside air temperature sensor, 50 Accelerator position sensor, 52 Brake pedal position sensor, 54 Shift position sensor, 56, 58 Braking part, 62, 64 Temperature sensor, 100 vehicle, 220 wheel hub, 230 wheel disc, 302 stop time measurement unit, 304, 344, 354 comparison unit, 306, 312 register unit, 308 first estimation unit, 310, 374, 384 addition unit, 314 subtraction 316 second estimation unit 318 selection unit 342 352 Magnet temperature acquisition unit, 346, 356 Temperature increase request generation unit, 348, 358 Heat generation amount integration unit, 362 Driver request calculation unit, 364 Total output calculation unit, 366 Battery state calculation unit, 368 Driving force distribution unit, 372, 382 Maximum torque calculation section, 410 rotor, 420 stator core, 430 stator coil, 440 bearing section, 450 rotating shaft, 460 joint section, 500 brake disc, 510 brake caliper, 520 hydraulic pressure generator, 530 brake pad, 610 first gear, 620 2nd gear, 630 3rd gear, B battery, C2 capacitor, D1-D8 diode, ENG engine, FL left front wheel, FR right front wheel, L1 reactor, MG1, MG2, MGR, MGL motor generator, PSD power split mechanism, Q ~Q8 each switching element, RL left rear wheel, RR right rear wheel.

Claims (4)

A vehicle,
An electric motor that is mechanically coupled to the wheel and drives the wheel using electromagnetic force from a permanent magnet;
A braking portion that is disposed in proximity to the electric motor and brakes rotation of the wheel by frictional force;
Magnet temperature acquisition means for acquiring the temperature of the permanent magnet;
Based on the acquired permanent magnet temperature, determination means for determining the necessity of temperature rise for the electric motor,
When it is determined that it is necessary to raise the temperature of the electric motor, the electric motor is controlled so that a driving torque obtained by adding a predetermined incremental torque to a required torque determined according to the driving situation of the vehicle is generated, and Bei example and control means for braking torque corresponding to the incremental torque controls the braking portion to generate,
The vehicle in which the electric motor and the braking unit are incorporated in a wheel of the wheel so that heat generated in the braking unit is transmitted to the electric motor .   The vehicle according to claim 1, wherein the control means determines the incremental torque so that the drive torque matches a maximum torque that can be output in the electric motor. The motor is
A rotor in which the permanent magnet is embedded;
And a stator for generating a current magnetic field for rotating the rotor, vehicle according to claim 1 or 2. A method of raising a temperature of an electric motor mounted on a vehicle,
The vehicle is
The motor mechanically coupled to the wheel and driving the wheel using electromagnetic force from a permanent magnet;
A braking portion that is disposed in proximity to the electric motor and brakes rotation of the wheels by frictional force;
The electric motor and the braking unit are incorporated in the wheel of the wheel so that heat generated in the braking unit is transmitted to the electric motor,
The temperature raising method is:
Obtaining a temperature of the permanent magnet;
Determining the need for temperature rise for the motor based on the acquired permanent magnet temperature;
Controlling the electric motor to generate a driving torque obtained by adding a predetermined incremental torque to a required torque determined according to the driving situation of the vehicle when it is determined that the electric motor needs to be heated; and
And a step of controlling the braking section so that a braking torque corresponding to the incremental torque is generated when it is determined that the temperature of the electric motor needs to be increased.

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