JP5648412B2 - Stator temperature estimation device - Google Patents

Description

  The present invention relates to a stator temperature estimation device that estimates the maximum temperature of a stator for a rotating electrical machine from the temperature detected by a temperature sensor that detects the temperature of the stator for the rotating electrical machine or the temperature of a portion related to the temperature of the stator.

  2. Description of the Related Art Conventionally, a hybrid vehicle in which an engine and a traveling motor are mounted and wheels are driven using at least one of the engine and the traveling motor as a drive source, and an electric vehicle such as an electric vehicle have been considered and implemented. Moreover, in such an electric vehicle, since the motor performance cannot be effectively exhibited when the motor becomes excessively high in temperature, the detected temperature of the motor is estimated.

  For example, Patent Document 1 describes a temperature protection device for a rotating electrical machine in which a thermistor sensor is attached to a stator of the rotating electrical machine and overheating protection of the rotating electrical machine is performed based on a temperature state signal thereof. This temperature protection device incorporates a map representing the relationship between the rotational speed of the rotating electrical machine and the protection temperature into the temperature protection control flow, and performs overheat protection by comparing the temperature signal of the thermistor sensor and the protection temperature of the map. Yes. In addition to Patent Document 1, there is Patent Document 2 as a prior art document related to the present invention.

JP 11-355959 A JP 2008-245412 A

  As in the temperature protection device for a rotating electrical machine described in Patent Document 1 above, it has been conventionally considered that a temperature sensor attached to a stator is used to protect the rotating electrical machine from overheating. Has a heat distribution. For this reason, it is only necessary that the same part of the stator has the highest temperature, but in reality, this is not the case, and the temperature detected by the temperature sensor is not necessarily the highest temperature of the stator. Under such circumstances, it has been conventionally considered to estimate the actual maximum temperature of the stator from the temperature rise width of the temperature sensor.

  For example, it can be estimated that the temperature sensor is close to the maximum temperature when the temperature sensor has a large increase range in a certain time range. It can be estimated that the temperature is far away. For this reason, the temperature divergence, which is the temperature divergence width or the temperature divergence rate between the actual maximum stator temperature and the detected temperature, is estimated from the increase in the temperature detected by the temperature sensor over a certain time range, and the stator The maximum temperature can be estimated. On the other hand, in the vehicle, when the start switch for starting and stopping the operation of the vehicle control system including the stator temperature estimation device is turned on, it is possible to perform calculations for estimating the temperature rise width and the temperature deviation. While the start switch is turned off, the calculated value of the temperature deviation is reset and disappears. For this reason, even if the user turns on the start switch again to restart the operation of the vehicle, the actual temperature divergence is unknown. Therefore, it is necessary to perform a calculation for estimating the temperature rise again. In this case, there is a possibility that the output of the rotating electrical machine cannot be effectively exhibited until the accurate maximum temperature is estimated. Thus, there is a possibility that the maximum temperature of the stator at the initial stage when the start switch is turned on again cannot be accurately estimated.

  On the other hand, it is also conceivable that the temperature deviation at the time when the start switch is turned off is stored while the start switch is turned off, and the temperature deviation is used when the start switch is turned on again. However, when the start switch is off, the temperature of the stator decreases with time, and the actual temperature divergence changes accordingly.Therefore, the difference between the stored temperature divergence and the actual temperature divergence Produce. For this reason, the actual temperature deviation is unknown, and there is a possibility that the maximum temperature of the stator at the initial time when the start switch is turned on again cannot be accurately estimated.

  In Patent Document 2, information on the saturation temperature of the stator of the rotating electrical machine, which uses information on the rotational speed and torque of the rotating electrical machine as parameters, is stored in advance in a storage unit, and the detected rotational speed of the rotating electrical machine is stored. A temperature estimation device for a rotating electrical machine that estimates the stator temperature based on the number and torque and the stored information about the saturation temperature is described. In such a temperature estimation device, there is a possibility that the temperature of the stator can be estimated without using a temperature sensor. However, there is room for improvement in terms of accurately estimating the maximum temperature of the stator, and there is a possibility that the output of the rotating electrical machine cannot be effectively exhibited even when there is a margin in output from the viewpoint of temperature protection.

  An object of the present invention is to accurately estimate the maximum temperature of the stator at the initial time when the start switch is turned on again in the stator temperature estimation device.

The stator temperature estimation apparatus according to the present invention estimates the maximum temperature of a rotating electrical machine stator from the temperature detected by a temperature sensor that detects the temperature of a stator related to the rotating electrical machine or the temperature of a portion related to the stator temperature. And a stator normal temperature estimating means for estimating a temperature deviation that is a temperature deviation width or a temperature deviation estimation rate from a detected temperature of a temperature sensor and estimating a maximum temperature of the stator. When the start switch for starting and stopping the operation of the stator temperature estimation device is turned off, the temperature deviation of the temperature sensor is stored together with the detected temperature when the temperature sensor is turned off , and the stator related temperature when the start switch is turned off and on. ON / OFF temperature difference, which is the difference from the stator related temperature at the time, and a change in temperature deviation during the OFF period of the start switch Storage means for storing a relationship between the degree divergence changes, when again on the starting switch obtains the on-time temperature detected by the temperature sensor, it calculates the off temperature difference, the temperature deviation when the stored off was calculated A stator temperature estimation device comprising a stator initial temperature estimation means for estimating an initial maximum temperature when the stator is turned on according to an on / off temperature difference and a relationship between a previously stored on / off temperature difference and a temperature deviation change. It is.

  In the stator temperature estimation device according to the present invention, preferably, the storage unit stores a map representing a relationship between the on-off temperature difference and the off-time temperature deviation change rate as the relation between the on-off temperature difference and the off-time temperature deviation change. To do.

  Preferably, in the stator temperature estimation device according to the present invention, the stator initial temperature estimation means obtains a temperature sensor on-time detection temperature and calculates an on / off temperature difference when the start switch is turned on again. ON-time temperature divergence estimation unit that estimates the on-time temperature divergence from the calculated ON / OFF temperature difference and the stored off-time temperature divergence with reference to a map that represents the relationship between the on-off temperature difference and the off-time temperature divergence change rate. And an on-time maximum temperature estimator for estimating the initial maximum temperature when the stator is on from the estimated on-time temperature deviation and the on-time detected temperature.

  Preferably, in the stator temperature estimation device according to the present invention, the stator initial temperature estimation means estimates the initial maximum temperature when the stator is on only when a preset specific condition is satisfied.

  In the stator temperature estimation device according to the present invention, preferably, the stator initial temperature estimation means has, as the specific condition, a stop time estimated value from when the start switch is turned off to when it is on within a preset set time. Only the initial maximum temperature when the stator is on is estimated.

  Preferably, in the stator temperature estimation device according to the present invention, the rotating electrical machine is mainly used as a motor, and further includes a second temperature sensor for detecting the temperature of the second rotating electrical machine mainly used as a generator. The stator initial temperature estimating means acquires the second on-time detection temperature of the second temperature sensor when the start switch is turned on again, and further, as the specific condition, the on-time detection temperature of the temperature sensor is set in advance as a first condition. The temperature obtained when the first condition that is equal to or higher than the temperature is satisfied and the temperature sensor on-time detection temperature is lower than the preset first temperature, and the temperature sensor off-time detection temperature is subtracted from the on-time detection temperature. The first second temperature difference obtained by subtracting the second on-time detection temperature of the second temperature sensor from the on-temperature detection temperature of the temperature sensor is set in advance. Only the second conditions are satisfied is the case above the third temperature difference, to estimate the maximum temperature of the on-time initial stator.

  According to the stator temperature estimation device according to the present invention, it is possible to accurately estimate the maximum temperature of the stator at the initial stage when the start switch is turned on again.

1 is a schematic diagram showing a configuration of a hybrid vehicle including a stator temperature estimation device according to an embodiment of the present invention. It is a block diagram which shows the structure of the control part of FIG. FIG. 3 is a schematic half sectional view of the second motor generator of FIG. 1. It is a figure which shows one example of the relationship between the highest temperature of the stator of a 2nd motor generator, and two detected temperatures after a long time passes after starting switch-on. It is a figure which shows one example of the relationship between the highest temperature of the stator of a 2nd motor generator at the time of a start switch OFF, and detected temperature. It is a figure which shows an example of the relationship between the on-off temperature difference Tv of the 2nd motor generator used in embodiment of this invention, and the initial deviation ratio (beta) for calculating | requiring an actual initial temperature deviation. In the embodiment of the present invention, it is a flowchart showing a stator maximum temperature estimation method when the start switch is turned on again.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1 to 7 show an example of an embodiment of the present invention.

  The stator temperature estimation device according to the present embodiment is incorporated in a hybrid vehicle that is an electric vehicle and is used to estimate the temperature of the stator of a second motor generator (MG2) that is a traveling motor. As shown in FIG. 1, the hybrid vehicle 10 includes a vehicle control system 12, a power split mechanism 14, and wheels 18 connected to the drive shaft 16. The vehicle control system 12 includes an engine 20, a first motor generator (MG1) 22 and a second motor generator (MG2) 24 which are two rotating electric machines, and a control unit 28 (FIGS. 1 and 2). It is out. The first motor generator 22 is mainly used as a generator. The second motor generator 24 is mainly used as a traveling motor. Such a hybrid vehicle 10 is driven using at least one of the engine 20 and the second motor generator 24 as a drive source.

  FIG. 1 shows a case where the hybrid vehicle 10 is an FF vehicle that is a front-wheel drive vehicle with a front engine. However, the hybrid vehicle may be an FR vehicle that is a rear wheel drive vehicle with a front engine, a 4WD vehicle that is a four wheel drive vehicle, or the like. Further, in the following description, the case where the stator temperature estimation device is used by being incorporated in a hybrid vehicle will be described. However, the stator temperature estimation device according to the present invention is incorporated in an electric vehicle which is an electric vehicle, and It can also be used to estimate temperature.

  The power split mechanism 14 can split the power from the engine 20 into a path to the drive shaft 16 and a path to the first motor generator 22. The power split mechanism 14 is constituted by, for example, a planetary gear mechanism. For example, the rotating shaft of the first motor generator 22 is hollow, and the sun gear of the planetary gear mechanism is connected to the end of the rotating shaft. Further, the carrier connected to the planetary gear of the planetary gear mechanism is connected to the drive shaft of the engine 20 inserted through the inside of the rotation shaft of the first motor generator 22. Further, the output shaft 30 is connected to the ring gear of the planetary gear mechanism, and the rotation shaft of the second motor generator 24 is connected to the output shaft 30 directly or via a speed reducer such as another planetary gear mechanism (not shown). The output shaft 30 is connected to the drive shaft 16 connected to the wheel 18 via the speed reducer 32. The power split mechanism 14 can also be connected to the drive shaft of the engine 20 via a damper (not shown).

  The first motor generator 22 is a three-phase AC motor and can also be used as a starting motor for the engine 20. However, when the first motor generator 22 is used as a generator driven by the engine 20, the engine 20, at least a part of the torque transmitted through the carrier of the planetary gear mechanism is transmitted to the rotating shaft of the first motor generator 22 through the sun gear.

  The second motor generator 24 is a three-phase AC motor for generating a driving force of the vehicle, and can also be used as a generator, that is, for power regeneration.

  The rotation of the engine 20 is extracted to the output shaft 30 side and the first motor generator 22 side via the power split mechanism 14. The electric power generated by driving the first motor generator 22 is charged in a battery 34 that is a secondary battery. The battery 34 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. When the hybrid vehicle 10 is configured as an FR vehicle, the rotation of the output shaft 30 is transmitted to the rear wheels via the propeller shaft and the differential gear to drive the rear wheels.

  The vehicle control system 12 includes the control unit 28, the first inverter 36 for the first motor generator 22, the second inverter 38 for the second motor generator 24, the first inverter 36, and the second inverter 38. And a DC / DC converter (not shown) connected between the battery 34 and an accelerator operation amount sensor (not shown) for detecting a pedal operation amount that is an instruction amount of an accelerator pedal that is an acceleration instruction section. . The control unit 28 includes torque command calculation means 42 (FIG. 2) that calculates a torque command based on detection signals from an accelerator operation amount sensor, a vehicle speed sensor, and the like.

  The vehicle control system 12 also includes a stator temperature estimation device 44. The stator temperature estimation device 44 includes the motor generators 22, 24 and the control unit 28, the start switch 46 for starting and stopping the vehicle control system 12, and the stator related temperature of the second motor generator 24. MG2 temperature sensor 48 that is a first temperature sensor that detects the temperature of the stator, and MG1 temperature sensor 50 that is a second temperature sensor that detects the temperature of the stator of first motor generator 22. Detection signals from the MG2 temperature sensor 48 and the MG1 temperature sensor 50 are input to the control unit 28. The start switch 46 is connected to the control unit 28, and an on / off state of the start switch 46 is determined by an on / off determination unit 52 included in the control unit 28.

  FIG. 3 shows a half schematic sectional view of the second motor generator 24. The second motor generator 24 includes a stator 56 that is fixed to the inside of the case 54, a rotating shaft 58 that is rotatably supported by the case 54, and a rotor 60 that is fixed to the rotating shaft 58. The rotor 60 is disposed to face the inner side of the stator 56 in the radial direction. The stator 56 includes, for example, a stator core 62 made of a laminated body of magnetic steel plates, and a three-phase stator coil 64 wound around a plurality of teeth provided on the inner peripheral portion of the stator core 62. The stator 56 is supplied with each phase current from the second inverter 38 (FIG. 1) to the stator coil 64 of each phase. The rotor 60 is provided with permanent magnets (not shown) at a plurality of locations of a rotor core made of a laminated body of magnetic steel plates, for example. In such a second motor generator 24, a rotating magnetic field is generated in the stator 56 by supplying power to the stator coil 64, and the rotor 60 is rotationally driven by the influence of the rotating magnetic field.

  Further, in the stator coil 64, a part of the coil end 66 disposed outside from both axial end surfaces of the stator core 62 (for example, any one of the points A and B indicated by A and B in FIG. 3). An MG2 temperature sensor 48 is attached. The configuration of the first motor generator 22 and the mounting position of the MG1 temperature sensor 50 shown in FIG. 1 are the same as those of the second motor generator 24 and the MG2 temperature sensor 48. The configurations of the motor generators 22 and 24 are not limited to the above configuration, and various configurations can be adopted.

  As shown in FIG. 1, the DC voltage that is the output of the battery 34 is boosted by a DC / DC converter (not shown) and can be supplied to the first inverter 36 and the second inverter 38. The direct current voltage generated by the first motor generator 22 or the second motor generator 24 and output from one or both of the two inverters 36 and 38 is stepped down by a DC / DC converter (not shown). Thereafter, the battery 34 is supplied, and the battery 34 is charged. The inverters 36 and 38 and the DC / DC converter are controlled by the control unit 28.

  When the start switch 46 is turned on by the user, power supply from the auxiliary battery (not shown) to the control unit 28 is started, and further provided between the battery 34 and the first inverter 36 and the second inverter 38. By connecting a system relay (not shown), power can be supplied from the battery 34 to the inverters 36 and 38. When the start switch 46 is turned off by the user, the connection between the battery 34 and each of the inverters 36 and 38 is cut off by the system relay, and the supply of power from the auxiliary battery to the control unit 28 is stopped. That is, when the start switch 46 is turned on by the user, the control unit 28 is activated, the control unit 28 turns on the system relay, and the DC voltage of the battery 34 is supplied to the battery 34 side terminals of the inverters 36 and 38. The On the other hand, when the start switch 46 is turned off, the system relay is turned off, and the connection between the battery 34 and each of the inverters 36 and 38 is cut off.

  The two inverters 36 and 38 are connected in parallel to the battery 34. Each motor generator 22, 24 receives a control signal corresponding to the torque command value from the control unit 28, and controls switching of each switching element. For example, the first inverter 36 converts the DC voltage input from the battery 34 side into an AC voltage based on a signal corresponding to the torque command value input from the control unit 28 and drives the first motor generator 22. . In addition, when the first motor generator 22 generates power as the engine 20 is driven, the first inverter 36 converts the AC voltage obtained by the power generation into a DC voltage by the first inverter 36 and converts the AC voltage. DC voltage is supplied to the DC / DC converter. The DC / DC converter steps down the supplied DC voltage and then supplies it to the battery 34 to charge the battery 34.

  On the other hand, the second inverter 38 converts the DC voltage input from the battery 34 side into an AC voltage based on a signal corresponding to the torque command value input from the control unit 28, thereby generating a second motor generator. 24 is driven. The second inverter 38 also converts the AC voltage generated by the second motor generator 24 into a DC voltage during regenerative braking when the hybrid vehicle 10 is running, and supplies the converted DC voltage to the DC / DC converter. . The DC / DC converter steps down the supplied DC voltage and then supplies it to the battery 34 to charge the battery 34. The regenerative braking is performed when the accelerator pedal is not depressed and the battery 34 has a small amount of charge, and causes the second motor generator 24 to generate power.

  The control unit 28 includes a microcomputer having a CPU, a memory, and the like, and can include, for example, a motor controller called a motor ECU and an engine controller called an engine ECU. In the illustrated example, only one control unit 28 is illustrated as the control unit 28, but the control unit 28 may be appropriately divided into a plurality of components and connected to each other. For example, the control unit 28 may be divided into a part having a function of a motor controller, a part having a function of an engine controller, and an overall control part that collectively controls the whole called a hybrid ECU, and may be connected to each other. .

  Stator temperature estimation device 44 includes control unit 28 described above, and estimates the maximum temperature of stator 56 (FIG. 3) that is a stator for the rotating electrical machine of second motor generator 24 from the temperature detected by MG2 temperature sensor 48. . The estimated maximum temperature is used for overheating protection of the stator 56. For example, when the estimated maximum temperature is equal to or higher than a preset upper limit temperature, the torque command of the second motor generator 24 is reduced. Execute overheat protection control such as

  As shown in FIG. 2, the control unit 28 includes a storage unit 68, a normal temperature estimation unit 70, and a stator initial temperature estimation unit 72. The storage means 68 stores a program for executing the stator maximum temperature estimation control and a map such as a “normal temperature estimation map”. The “normal temperature estimation map” stores the relationship between the temperature rise width and the temperature deviation in the set time range of the MG2 temperature sensor 48 for each of a plurality of torque command areas of the second motor generator 24. The “torque command area” means a range of a range to which the command value belongs when a torque command value of the second motor generator is given.

  When a certain amount of time has elapsed after the start switch 46 is turned on, the torque command becomes equal to or greater than a certain torque command for which a map is set, so that the normal temperature estimation means 70 causes the stator of the second motor generator 24 to Estimate the maximum temperature of 56 (FIG. 3). As described in the above section [Problems to be Solved by the Invention], since the stator 56 actually has a heat distribution, the temperature detected by the MG2 temperature sensor 48 is not always the maximum temperature of the stator 56. . For this purpose, the normal temperature estimation means 70 estimates the maximum temperature of the stator 56 using the normal temperature estimation map.

FIG. 4 is a diagram showing an example of the relationship between the maximum temperature of the stator of the second motor generator and the detected temperatures at two locations after a long time has elapsed since the start switch was turned on. In the following description, the same elements as those shown in FIGS. 1 to 3 are denoted by the same reference numerals. FIG. 4 shows the temperature relationship of the stator 56 corresponding to the torque command region when the calculated torque command value of the second motor generator 24 is in the torque command region of one. Further, in FIG. 4, when it is assumed that temperature sensors are attached to two positions of the stator 56, that is, points A and B shown in FIG. The time variation of the temperature and the actual maximum temperature of the stator 56 is shown. Dashed T _M in FIG. 4, represents the actual maximum temperature of the stator, the solid line T _A represents the temperature output A check, a solid line T _B represents the B point detection temperature.

For example, the time indicated by the arrow T1 in FIG. 4, when comparing the temperature rise of the temperature T _A and B point detecting the temperature T _B out A check, increase the width of the A point detection temperature T _A is output B inspection It is larger than rise in temperature T _B. Further, the increase range of the maximum temperature T _M is further larger than the increase range of the point A detection temperature T _A. For this reason, for example, when the MG2 temperature sensor 48 is attached to one place of the stator 56, the temperature rise width in the T1 time and a plurality of temperatures between the detected temperatures T _A and T _B and the maximum temperature T _M shown in FIG. A normal temperature estimation map representing the relationship with the temperature deviation widths D1 and D2 is stored in the storage unit 68, and the temperature deviation widths D1 and D2 are estimated from the calculated temperature rise width with reference to the normal temperature estimation map. Can do. Further, the maximum temperature T _M of the stator 56 at the time T1 can be estimated from the estimated temperature deviation widths D1 and D2 and the detected temperatures T _A and T _B at the time T1 has elapsed. Further, when the calculated temperature rise width deviates from the temperature rise width of the stored map, the temperature deviation width and the maximum temperature of the stator 56 at the time T1 corresponding to the temperature calculated by linear interpolation or the like are obtained. presume. In the above description, for simplification of explanation, a case has been described in which the relationship between the detected temperature A and the detected temperature B and the relationship between the detected temperature and the time is stored. The temperature deviation width and the maximum temperature of the stator 56 can be estimated with higher accuracy from the temperature rise width.

  Based on such a principle, the normal temperature estimating means 70 is stored for each torque command area, and the temperature rise width in the set time range at the mounting position of the MG2 temperature sensor 48 and the maximum temperature of the stator 56. The maximum temperature of the stator 56 is estimated using a normal temperature estimation map representing the relationship with the temperature deviation. That is, the normal temperature estimating means 70 estimates a temperature deviation width that is a temperature deviation from the maximum temperature of the stator 56 from the temperature detected by the MG2 temperature sensor 48, and estimates the maximum temperature of the stator 56. As the temperature divergence estimated in this case, using the temperature divergence rate of the detected temperature of the MG2 temperature sensor 48 with respect to the maximum temperature of the stator 56, the estimated temperature divergence rate and the detected temperature of the MG2 temperature sensor 48 are The maximum temperature of the stator 56 can also be estimated.

However, once the start switch 46 is turned off, if the temperature switch is memorized when the start switch 46 is turned off, if the device is not devised, the stored temperature difference and the actual temperature with the passage of time. Deviation from deviation increases. This will be described with reference to FIG. FIG. 5 is a diagram showing an example of the relationship between the maximum temperature of the stator of the second motor generator and the detected temperature when the start switch is off. In FIG. 5, “IG off” indicates that the start switch 46 is off, and “IG on” indicates that the start switch 46 is on (the same applies to FIGS. 6 and 7 described later). In FIG. 5, the straight line T _M represents the maximum temperature of the stator 56, and the straight line Tα represents the actual temperature of the stator 56 at the position where the MG2 temperature sensor 48 is attached. As shown in FIG. 5, after the start switch 46 is turned off, the maximum temperature T _M and the temperature Tα at the position where the MG2 temperature sensor 48 is attached both decrease. For this reason, the actual temperature deviation (= T _M −Tα) between the start switch 46 being turned off gradually decreases. However, this temperature deviation is unknown because it is not calculated while the start switch 46 is off. For this reason, it is difficult to accurately estimate the maximum temperature of the stator 56 using the temperature deviation stored when the start switch 46 is turned on again when the user restarts the vehicle. The present embodiment has been conceived for the purpose of eliminating such inconvenience.

That is, the control unit 28 shown in FIG. 2 includes the storage unit 68 and the stator initial temperature estimation unit 72. The storage means 68 stores the OFF-time detected temperature Tα1 (FIG. 5) of the MG2 temperature sensor 48 when the start switch 46 is OFF, and also stores the OFF-time temperature deviation Dα1 (FIG. 5) at the OFF time. Further, the storage means 68 has an on / off temperature difference TV (T _V) which is a difference between a detected temperature Tα1 of the MG2 temperature sensor 48 when the start switch 46 is turned off and a detected temperature Tα2 of the MG2 temperature sensor 48 when the start switch 46 is turned on. = Tα2−Tα1) and an initial divergence estimation map representing the relationship is stored as the relationship between the off-time temperature divergence change rate described later and “initial divergence ratio β”. The “initial deviation ratio β” represents how much the temperature deviation decreases while the start switch 46 is turned off, and the start switch 46 is multiplied by the initial deviation ratio β by the temperature deviation Dα1 when the start switch 46 is turned off. An initial temperature divergence Dα2 (= β × Dα1) at the time of 46-on is obtained.

  FIG. 6 is a diagram illustrating an example of the relationship between the on / off temperature difference Tv of the second motor generator and the initial deviation ratio β for obtaining the actual initial temperature deviation used in the present embodiment. As shown in FIG. 6, as the absolute value of the on / off temperature difference Tv becomes larger (as it goes to the left in FIG. 6), the initial deviation ratio β becomes smaller, Tv is A ° C., and β is zero. The storage unit 68 stores an initial deviation estimation map representing the relationship between the on / off temperature difference Tv and the initial deviation ratio β.

Further, the stator initial temperature estimating means 72 acquires the on-time detection temperature Tα2 (FIG. 5) detected by the MG2 temperature sensor 48 when the start switch 46 is turned on again, and MG2 stored in the storage means 68. Based on the detected temperature Tα1 when the temperature sensor 48 is off (FIG. 5) and the detected temperature Tα2 when the stator 56 is on, the initial maximum temperature T _M2 when the stator 56 is on is estimated (FIG. 5). More specifically, as shown in FIG. 2, the stator initial temperature estimation means 72 includes a temperature difference calculation unit 74, an on-time temperature deviation estimation unit 76, and an on-time maximum temperature estimation unit 78. In addition, the stator initial temperature estimating means 72 obtains the on-time detected temperature Tα2 of the MG2 temperature sensor 48 by the temperature difference calculating unit 74 when the start switch 46 is turned on again after being turned off, and from the detected temperatures Tα1 and Tα2. An on / off temperature difference Tv (= Tα2−Tα1) is calculated.

  In addition, the stator initial temperature estimation means 72 calculates the on-off temperature difference Tv from the off-time temperature deviation Dα1 (FIG. 5) stored in the storage means 68 by the on-time temperature deviation estimation unit 76 and the calculated on-off temperature difference Tv. The initial divergence ratio β corresponding to (FIG. 6) is acquired. In this case, the stator initial temperature estimating means 72 refers to the initial deviation estimation map representing the relationship between the on / off temperature difference Tv and the initial deviation ratio β of FIG. A corresponding initial divergence ratio β is obtained. For example, when the on / off temperature difference Tv is a certain value between 0 ° C. and A ° C., the initial deviation ratio β is a value obtained from the relationship of FIG. Next, the on-time temperature deviation estimation unit 76 multiplies the acquired initial deviation ratio β by the off-time temperature deviation Dα1 (FIG. 5) to calculate, ie, estimate, the on-time temperature deviation Dα2 (FIG. 5). To do. That is, Dα2 is calculated from Dα2 = β × Dα1.

Next, the stator initial temperature estimating means 72 calculates the stator 56 from the ON-time temperature deviation Dα2 estimated by the ON-time maximum temperature estimating unit 78 (FIG. 2) and the ON-time detected temperature Tα2 (FIG. 5) of the MG2 temperature sensor 48. Estimate the maximum temperature T _M2 (FIG. 5) at the initial time of ON. More specifically, the on-time maximum temperature estimation unit 78 adds the estimated on-time temperature deviation Dα2 to the on-time detected temperature Tα2 of the MG2 temperature sensor 48, so that the initial maximum temperature T when the stator 56 is on. _M2 (= Tα2 + Dα2) is estimated. In this description, the case where the temperature deviation width is used as the temperature deviation between the maximum temperature of the stator 56 and the actual detected temperature has been described. However, the temperature divergence rate can also be used as the temperature divergence. In this case, the on-time detected temperature Tα2 of the MG2 temperature sensor 48 is multiplied or divided by the on-time temperature divergence Dα2. Estimate the maximum temperature T _M2 .

Further, the stator initial temperature estimating means 72 is not limited to a configuration for estimating the initial maximum temperature T _M2 when the stator 56 is turned on in all cases when the start switch 46 is turned on again. A configuration for estimating the initial maximum temperature T _M2 when the stator 56 is on can also be employed only when the “specific condition” is satisfied. For example, the stator initial temperature estimation means 72 determines that the "specific condition" is when the stator 56 is on only when the estimated stop time from when the start switch 46 is off to when it is on is within a preset set time. A configuration for estimating the initial maximum temperature T _M2 may be employed. In this case, for example, a timer or a calendar for calculating the date is provided in the stator temperature estimating device 44, and the stop time from when the start switch 46 is turned off to when the start switch 46 is turned on can be estimated by the timer, the calendar, or the like. Further, when the estimated stop time exceeds the set time, the normal temperature estimating means 70 is used and the temperature rise width of the MG2 temperature sensor 48 is calculated without using the stator initial temperature estimating means 72. The maximum temperature of the stator 56 is estimated from the temperature rise width using the normal temperature estimation map.

The stator initial temperature estimating means 72 is a second temperature sensor for detecting the temperature of the first motor generator 22 mainly used as a generator when the start switch 46 is turned on again. The on-time detected temperature Tγ2 can also be acquired. Then, the stator initial temperature estimating means 72 is the initial maximum temperature T _M2 when the stator 56 is turned on only when the “first condition is satisfied” or “the second condition is satisfied” as the “specific condition”. It is also possible to adopt a configuration that estimates

  In this case, a case where the detected temperature Tα2 when the MG2 temperature sensor 48 is on is equal to or higher than a preset first temperature Ta (eg, 70 ° C.) (Tα2 ≧ Ta) is defined as “first condition satisfied”. Further, the on-time detection temperature Tα2 of the MG2 temperature sensor 48 is less than a preset first temperature Ta (eg, 70 ° C.) (Tα2 <Ta), and the on / off temperature difference Tv calculated by the temperature difference calculation unit 74 is positive or negative. , That is, a temperature difference Tva (= Tα1−Tα2) obtained by subtracting the on-time detection temperature Tα2 from the off-time detection temperature Tα1 of the MG2 temperature sensor 48 is set to a second temperature difference Tb (for example, 10 ° C.) set in advance. ) (Tva <Tb), and the first second temperature difference Tw (=) obtained by subtracting the second on-time detection temperature Tγ2 of the MG1 temperature sensor 50 from the on-time detection temperature Tα2 of the MG2 temperature sensor 48. When Tα2−Tγ2) is a preset third temperature difference Tc and exceeds a third temperature difference Tc (for example, 5 ° C.) less than the second temperature difference Tb (Tw> Tc), “the second condition is satisfied” To. In this case, if neither the first condition nor the second condition is satisfied, it is determined that the vehicle has been left for a long time with the start switch 46 turned off, and the temperature deviation stored in the storage means 68 is reset. Then, the stator temperature estimation device 44 calculates the temperature increase width of the MG2 temperature sensor 48 by the normal temperature estimation means 70 without using the stator initial temperature estimation means 72, and the normal temperature estimation map from the calculated temperature increase width. Is used to estimate the maximum temperature of the stator 56.

  Next, a method for estimating the maximum temperature of the stator 56 when the start switch 46 is turned on again using the first condition and the second condition will be described with reference to the flowchart of FIG. FIG. 7 is a flowchart showing a method for estimating the maximum stator temperature when the start switch is turned on again in the present embodiment.

First, after it is determined by the on / off determination means 52 (FIG. 2) that the start switch 46 has been turned on again after being turned off, in step S10 (hereinafter, “step S” will be described simply as “S”), the control unit. 28 determines whether or not the on-time detection temperature Tα2 (FIG. 5) of the MG2 temperature sensor 48 is lower than the first temperature Ta ° C., that is, whether or not the on-time detection temperature Tα2 is high. When the on-time detection temperature Tα2 is not lower than Ta ° C., that is, is equal to or higher than Ta ° C. (Tα2 ≧ Ta ° C.), the process proceeds to S12. In S12, it is determined that the first condition is established, and it is determined that the vehicle has not been left for a long time with the start switch 46 turned off. Then, the stator initial temperature estimation means 72 refers to the initial deviation estimation map (see FIG. 6) from the calculated on-off temperature difference Tv and the off-time temperature deviation Dα1 stored in the storage means 68, and refers to the on-off temperature difference. An initial deviation ratio β corresponding to Tv is acquired, and an on-time temperature deviation Dα2 that is an initial deviation is estimated from β × Dα1 from the acquired initial deviation ratio β. Next, the initial maximum temperature T _M2 when the stator 56 is on is estimated from the estimated on-time temperature deviation Dα2 and the detected temperature Tα2 of the MG2 temperature sensor 48.

  On the other hand, when it is determined in S10 that the detected temperature Tα2 when the MG2 temperature sensor 48 is on is lower than the preset first temperature Ta Ta ° C. (Tα2 <Ta ° C.) in S10. The process proceeds to S14. In S14, the temperature difference Tva (= Tα1-Tα2) obtained by subtracting the on-time detection temperature Tα2 from the off-time detection temperature Tα1 of the MG2 temperature sensor 48 is equal to or greater than the second temperature difference Tb ° C (Tva ≧ Tb ° C). It is determined whether or not the temperature of the MG2 temperature sensor 48 has greatly decreased during the OFF state. In this case, if the temperature difference Tva is equal to or greater than Tb ° C., the process proceeds to S16, where it is determined that the vehicle has been left for a long time in the off state of the start switch 46, and the temperature deviation stored in the storage means 68 is reset. Then, without using the stator initial temperature estimation means 72, the normal temperature estimation means 70 is used to calculate the temperature rise width of the MG2 temperature sensor 48, and the normal temperature estimation map is used from the calculated temperature rise width, using the normal temperature estimation map. A maximum temperature of 56 is estimated. However, in this case, since the temperature rise is calculated, it takes longer to estimate the maximum temperature of the stator 56 than when the stator initial temperature estimating means 72 is used.

  Further, when it is determined in S14 that the temperature difference Tva is less than Tb ° C. (Tva <Tb ° C.), the process proceeds to S18, and in S18, the MG1 temperature sensor 50 is detected from the on-time detection temperature Tα2 of the MG2 temperature sensor 48. It is determined whether or not the first second temperature difference Tw (= Tα2−Tγ2) obtained by subtracting the second on-time detected temperature Tγ2 is equal to or less than the third temperature difference Tc ° C. (Tw ≦ Tc ° C.). That is, it is determined whether or not the temperature of the second motor generator 24 is close to the temperature of the first motor generator 22 that is mainly used as a generator and is considered to have a low temperature rise during use. When it is determined that the first second temperature difference Tw is equal to or less than Tc ° C. (Tw ≦ Tc ° C.), the process proceeds to S20, where it is determined that the first temperature difference is left for a long period of time. The maximum temperature of the stator 56 is estimated by the temperature estimating means 70.

On the other hand, when it is determined in S18 that the first second temperature difference Tw exceeds Tc ° C. (Tw> Tc ° C.), the process proceeds to S22, where the second condition is satisfied, and the vehicle is operated by the start switch 46. It is judged that it has not been left for a long time in the off state. Then, similarly to S 12, the stator initial temperature estimation means 72 estimates the on-time temperature deviation Dα 2, which is the initial deviation, from the calculated on-off temperature difference Tv and the off-time temperature deviation Dα 1 stored in the storage means 68. The initial maximum temperature T _M2 when the stator 56 of the second motor generator 24 is turned on is estimated from the ON temperature deviation Dα2.

According to such a stator temperature estimation device 44, the storage means 68 stores the off-time detected temperature Tα1 of the MG2 temperature sensor 48 when the start switch 46 is turned off, and the stator initial temperature estimation means 72 is started. When the switch 46 is turned on again, the on-time detection temperature Tα2 of the MG2 temperature sensor 48 is acquired, and when the stator 56 of the second motor generator 24 is on based on the off-time detection temperature Tα1 and the on-time detection temperature Tα2. Estimate the initial maximum temperature T _M2 . In this case, from the on / off temperature difference Tv (= Tα2−Tα1), a change in actual temperature deviation between the maximum temperature of the stator 56 and the temperature at the mounting position of the MG2 temperature sensor 48 while the start switch 46 is off is accurately estimated. Therefore, the initial temperature deviation when the start switch 46 is turned on again can be accurately estimated. Therefore, it is possible to accurately estimate the maximum temperature T _M2 of the stator 56 when the start switch 46 is turned on again.

  In the flowchart shown in FIG. 7, the first temperature Ta ° C., the second temperature difference Tb ° C., and the third temperature difference Tc ° C., which are set to determine whether or not to leave for a long period of time, are various appropriate temperatures. Can be set to

  Further, in the present embodiment, in order to obtain the initial temperature deviation of the second motor generator 24, the initial deviation estimation map representing the relationship between the on / off temperature difference Tv and the initial deviation ratio β in FIG. 6 is used. However, instead of the initial deviation ratio β, an initial deviation estimation map representing the relationship between the on / off temperature difference Tv of the MG2 temperature sensor 48 and the magnitude of the decrease from the temperature deviation at the time when the start switch 46 is turned off can be used. . In this case, if a decrease width corresponding to the on / off temperature difference Tv is obtained, this decrease width can be subtracted from the temperature difference when the start switch 46 is turned off to accurately estimate the temperature difference when the start switch 46 is turned on. .

  Further, the estimation of the maximum temperature of the stator 56 in the initial state when the start switch 46 is turned on is performed only when a predetermined condition is set in advance, for example, an estimated stop time value from when the start switch 46 is turned off to when the start switch 46 is turned on. Only when it is within the set time, or when it is performed only when the first condition or the second condition is satisfied, the accuracy of estimating the maximum temperature of the stator 56 at the beginning when the start switch 46 is turned on is more effective. Can be expensive.

  Further, in the method of estimating the maximum temperature of the stator 56 at the initial time when the start switch 46 is turned on in FIG. 7, the detected temperature at the time of turning on the MG1 temperature sensor 50 for the first motor generator 22 mainly used as a generator is left for a long time. Used to determine whether or not. However, the on-time detected temperature of the MG1 temperature sensor 50 is not used, and instead, other temperature with low temperature and small fluctuation, for example, oil for cooling the second motor generator 24 and the first motor generator 22 is used. It is also possible to detect the temperature of the refrigerant such as cooling water and determine whether or not to leave for a long period of time using the temperature and the detected temperature of the MG2 temperature sensor 48. For example, if the refrigerant temperature and the temperature detected by the MG2 temperature sensor 48 are large, it can be determined that the refrigerant is not left for a long time.

  In the present embodiment, as the stator related temperature, the temperature of the stator 56 of the second motor generator 24 is directly detected by the MG2 temperature sensor 48, and this detected temperature is used to start the stator when the start switch 46 is turned on. A maximum temperature of 56 is estimated. However, another temperature related to the temperature of the stator 56 of the second motor generator 24, for example, the temperature of the case 54 (FIG. 3) that supports the stator 56 is detected as the stator related temperature, and the detected temperature is used to start It is also possible to estimate the maximum temperature of the stator 56 when the switch 46 is on.

  In the above description, the case where the maximum temperature of the stator 56 of the second motor generator 24 is estimated in the hybrid vehicle having the first motor generator 22 and the second motor generator 24 has been described. The present invention can also be applied when the first motor generator 22 is a simple generator.

  DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Vehicle control system, 14 Power split mechanism, 16 Drive shaft, 18 wheels, 20 Engine, 22 1st motor generator (MG1), 24 2nd motor generator 24 (MG2), 28 Control part, 30 Output shaft , 32 reducer, 34 battery, 36 first inverter, 38 second inverter, 40 accelerator operation amount sensor, 42 torque command calculation means, 44 stator temperature estimation device, 46 start switch, 48 MG2 temperature sensor, 50 MG1 temperature sensor, 52 ON / OFF determining means, 54 case, 56 stator, 58 rotating shaft, 60 rotor, 62 stator core, 64 coil end, 66 storage means, 70 normal temperature estimating means, 72 stator initial temperature estimating means, 74 temperature difference calculating section, 76 ON Temporal temperature deviation estimation part, 78 Maximum temperature estimator when on.

Claims (6)

A stator temperature estimation device for estimating a maximum temperature of a stator for a rotating electrical machine from a detection temperature of a temperature sensor for detecting a stator related temperature which is a temperature of a stator for a rotating electrical machine or a temperature of a portion related to the temperature of the stator,
A normal stator temperature estimating means for estimating a temperature deviation that is a temperature deviation width or a temperature deviation estimation rate from the detected temperature of the temperature sensor and estimating the stator maximum temperature ;
At start and off the start switch for deactivation of the stator temperature estimating device, together with the off-time of the temperature detected by the temperature sensor, and stores the temperature deviation when off, and stator temperature concerned and on at the time of off of the start switch Storage means for storing a relationship between an on-off temperature difference that is a difference between the stator-related temperature and an off-time temperature deviation change that represents a change in temperature deviation during an off period of the start switch ;
When the start switch is turned on again, the temperature sensor on-time detection temperature is acquired, the on-off temperature difference is calculated, the stored off-time temperature deviation, the calculated on-off temperature difference, the pre-stored on-off temperature difference, and temperature A stator initial temperature estimation device comprising: an initial stator temperature estimation means for estimating an initial maximum temperature when the stator is turned on in accordance with a relation of deviation change. In the stator temperature estimation device according to claim 1 ,
The storage means stores a map representing a relationship between an on-off temperature difference and an off-time temperature deviation change rate as a relationship between an on-off temperature difference and an off-time temperature deviation change. In the stator temperature estimation device according to claim 1 ,
The stator initial temperature estimation means is:
When the start switch is turned on again, a temperature difference calculation unit that obtains an on-detection temperature of the temperature sensor and calculates an on / off temperature difference;
An on-time temperature deviation estimation unit that estimates an on-time temperature deviation from a calculated on-off temperature difference and a stored off-time temperature deviation with reference to a map representing a relationship between the on-off temperature difference and the off-time temperature deviation change rate;
A stator temperature estimation device, comprising: an on-time maximum temperature estimation unit that estimates an initial maximum temperature of the stator when it is on from an estimated on-time temperature deviation and an on-time detected temperature. In the stator temperature estimation device according to any one of claims 1 to 3 ,
The stator initial temperature estimation means estimates the initial maximum temperature when the stator is on only when a preset specific condition is satisfied. In the stator temperature estimation device according to claim 4 ,
The stator initial temperature estimating means estimates the initial maximum temperature when the stator is on only when the estimated stop time from when the start switch is off to when it is on is within a preset time as a specific condition. A stator temperature estimation device. In the stator temperature estimation device according to claim 4 ,
Rotating electrical machines are mainly used as motors,
Furthermore, a second temperature sensor for detecting the temperature of the second rotating electrical machine used mainly as a generator is provided,
The stator initial temperature estimating means acquires the second on-time detected temperature of the second temperature sensor when the start switch is turned on again,
Furthermore, as the specific condition, when the first condition is established, the temperature sensor on-time detection temperature is equal to or higher than the preset first temperature, the temperature sensor on-time detection temperature is less than the preset first temperature, and The temperature difference obtained by subtracting the ON detection temperature from the OFF detection temperature of the temperature sensor is less than a preset second temperature difference, and the second ON of the second temperature sensor is detected from the ON detection temperature of the temperature sensor. The initial maximum temperature when the stator is on is estimated only when the second condition, which is a case where the first second temperature difference obtained by subtracting the hourly detected temperature exceeds a preset third temperature difference, is established. A stator temperature estimating device.

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